WO2008029911A1

WO2008029911A1 - Planar light source element, light control member using the same, and image display device using the same

Info

Publication number: WO2008029911A1
Application number: PCT/JP2007/067490
Authority: WO
Inventors: Yoshimi Ohta; Ikuo Onishi
Original assignee: Kuraray Co., Ltd.
Priority date: 2006-09-08
Filing date: 2007-09-07
Publication date: 2008-03-13
Also published as: TW200834003A; JPWO2008029911A1

Abstract

A planar light source element includes a light control member having a first light control unit formed by a plurality of ribbed convex portions (1) and a second light control unit formed by a plurality of ribbed convex portions (2). It is assumed that the length of one cycle of point-shaped light sources in the X-axis direction is D1, the length of one cycle of the point-shaped light source in the Y-axis direction is D2, the distance between the point-shaped light sources and the first light control unit is H1, the distance between the point-shaped light sources and the second light control unit is H2, the center position of an arbitrarily selected point-shaped light source is an origin, the position coordinate in the X-axis direction is X, and the position coordinate in the Y-axis direction is Y. The ratio of the maximum value against the minimum value of the light emission intensity of the light incident into the first light control unit in the direction toward the front surface at X and the light emission intensity of the light incident into the second light control unit in the direction toward the front surface at Y in three cycles is not smaller than 0.8. The cross section of the ribbed convex portions (1) in the X direction has a shape formed having different inclinations expressed by D1, H1, X and the cross section of the ribbed convex portions (2) in the Y direction has a shape formed having different inclinations expressed by D2, H2, Y.

Description

Specification

Surface light source element, light control member used therefor, and image display device using the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a surface light source element having a plurality of point light sources, a sheet-like light control member provided in the surface light source element, and an image display device using the same. The present invention relates to a direct-type surface light source element used in lighting signage devices, liquid crystal display devices, and the like that are required to have high performance, a light control member included in the surface light source element, and an image display device using the light control member.

Background art

[0002] For example, surface light source elements used in image display devices include an edge light method and a direct method. The edge light method is a method in which light from a light source arranged on the end face of the light guide plate is taken out from the main surface perpendicular to the end face by the light guide plate in the front direction. This is a system in which light is incident on the diffuser plate, light is made uniform by the diffuser plate, and light is extracted to the exit surface opposite to the incident surface.

[0003] Since image display devices used for mobile phones and mopile personal computers are required to be thin, an edge light system that is advantageous for thinness is mainly used by providing a light source at the side end of the device. . On the other hand, for television and personal computer monitors, there are increasing demands for larger, higher brightness, and lower power consumption image display devices. In a large screen, the ratio of the length of the periphery to the screen area decreases, and sufficient brightness cannot be obtained. In addition, the light guide plate becomes thick and the weight increases. Therefore, the direct type is the mainstream for large surface light source elements.

[0004] In the direct-type surface light source element, improvement in luminance uniformity, improvement in front luminance, reduction in thickness, and reduction in power consumption, that is, energy saving are required. Luminance uniformity is particularly important for eliminating the light / dark difference in the screen due to the light source image, and is important for applications such as image display devices and illuminated signboards.

[0005] A direct-type surface light source element includes a light source, a reflection plate, a diffusion plate, a diffusion sheet, and the like! Anti The projecting plate reflects the light emitted from the light source to the back side in the front direction, and the diffusion plate has a function of reducing the image of the light source in which fine particles that diffuse the light are dispersed.

[0006] Fluorescent lamps, which are linear light sources, have been used as the light source, but there are problems such as poor color reproducibility and the burden on the environment due to the use of mercury. . Therefore, it has been proposed that a point light source such as a light emitting diode (LED) or the like is arranged in a plane and used as a planar light source (for example, a non-light source) that has good color reproducibility and does not use mercury. (See Patent Document 1).

However, when the point light source is arranged in a plane, a light / dark difference due to the light source image is generated two-dimensionally. In addition, it is more difficult to obtain high luminance uniformity with strong directivity than LED linear light sources. Also, when using LEDs of each color such as red, blue, and green in order to widen the color coordinates, it is difficult to obtain color uniformity. Increasing the number of fine particles on the diffuser can increase brightness uniformity and color uniformity. Light absorption and light emitted in unnecessary directions increase, reducing the light utilization efficiency. From the viewpoint of energy saving, it is not preferable.

[0008] On the other hand, a method of erasing a light source image by dispersing the light from the LED by giving the LED package a unique shape has also been proposed (for example, see Patent Document 1). However, it is not preferable because the package prevents the surface light source element from being thinned and the productivity is lowered.

[0009] Further, a method of providing a light guide unit that makes the light of the LED uniform is also proposed (see, for example, Patent Document 2), but the productivity decreases and the weight of the surface light source element increases. This is not desirable.

[0010] In addition, a method has been proposed in which a pattern is provided on a diffusion plate in which fine particles for diffusing light are dispersed in accordance with the arrangement of point light sources (see, for example, Patent Document 3). However, because it requires strict alignment with the point light source, productivity is reduced, and by changing the size of the surface light source element, luminance uniformity and color uniformity are greatly reduced. I don't like it.

Patent Document 1: Japanese Patent Laid-Open No. 2005-340750

Patent Document 2: Japanese Patent Laid-Open No. 2005-327682

Patent Document 3: Japanese Patent Laid-Open No. 2005-38643 Non-Patent Document 1: flat-panel display2004 Business Edition pl 70 Nikkei BP Publishing Invention Disclosure

Problems to be solved by the invention

Therefore, in the present invention, for example, a direct-type surface light source element used in an image display device or the like, which enables high color reproducibility using a point light source such as an LED, and has high light use efficiency. Therefore, there is no change in the optical design of the light control component, brightness reduction, brightness uniformity, and color uniformity deterioration due to the increase in size, which is high brightness and high brightness uniformity and color uniformity. Therefore, it is easy to respond to the increase in size, and it is possible to obtain high brightness and color uniformity in the front direction without strict alignment between the light source and other members. An object of the present invention is to provide a sheet-like light control member and an image display device using the same.

Means for solving the problem

That is, the present invention provides the following means for solving the above problems.

According to a first aspect of the present invention, there is provided at least an exit surface parallel to the XY plane, with one of the normals of the XY plane parallel to the X axis and the Y axis orthogonal to the X axis as the front direction. A plurality of point light sources and two sheet-like light control members,

The plurality of point light sources are periodically arranged in the X-axis and Y-axis directions in a virtual plane parallel to the XY plane, and include a light emitting surface parallel to the XY plane,

The light control member is arranged in parallel to the XY plane and in the front direction of the plurality of point light sources, and the emission surface is arranged on the front direction side of the light control member. An element,

Of the two sheets, a first light control unit comprising a plurality of hook-shaped convex portions 1 orthogonal to the X-axis direction and parallel to the Y-axis direction is provided on the exit surface side of one light control member,

And,

Of the two light control members, a second light control unit comprising a plurality of hook-shaped convex portions 2 parallel to the X-axis direction and perpendicular to the Y-axis direction is provided on the other exit surface side. And

The center position of the point light sources arbitrarily selected, where D is the length of one cycle along the X axis and D is the length of one cycle along the Y axis. The origin, X-axis direction The light emitting surface of the selected point light source and the first light in a plane parallel to the X-axis direction and perpendicular to the Y-axis direction, where X is the position coordinate and Y is the position coordinate in the Y-axis direction. The distance from the control unit is H, and the function of the light incident on the first light control unit from the selected point light source in the direction of the front surface of the exit surface at X is f (X),

g (X) = f (X-D) + f (X) + f (X + D)

And

The ratio of g (X), the minimum value of g (X), to g (X), the maximum value, g (X) / g (X)

1 1 mm 1 max 1 mm 1 ma¾ is 0.8 or more,

The minimum value X of X is — 3. OD ≤X 0.5.

min 1 min 1

The maximum value of X is in the range of 0.5D ≤X ≤3.0D

max 1 max 1

(X and X are centered around an arbitrarily selected point light source with f (X) value x = o mm max 1

, The coordinates of both ends to become 0)

The cross-sectional shape in the X-axis direction of any bowl-shaped convex part 1 is composed of (2N + 1) differently inclined areas N to N represented by the following formula:

δ = (X --X) / (2N +1)

1 max mm 1

X = iX δ

a = tan ^_1 (X / H)

Φ = tan— ((n -sin / 3) / (n -cos β 1))

li 1 li 1 li

N: Natural number

i: -N force, etc. Integer of N

n: Refractive index of hook-shaped convex part 1 of the first light control part

n: Refractive index of the base material of the first light control unit

Is

a: The width of area i in the X-axis direction Φ: Slope inclination with respect to the exit surface of region i

li

τ: thickness from the incident surface of the first light control unit to the bottom of the bowl-shaped convex part 1

I (α): arbitrarily selected point light source power Unit angle in the direction of α along the X-axis direction

1 li li

Intensity of light emitted per degree

And,

In a plane perpendicular to the X-axis direction and parallel to the Y-axis direction!

The distance between the light emitting surface of the selected point light source and the second light control unit is H,

2

A function that expresses the intensity of light incident on the second light control unit from the selected point light source in the direction of the front surface of the exit surface in the position coordinate Y in the Y-axis direction is represented by f (Y),

2

g (Y) = f (YD) + f (Y) + f (Y + D)

The ratio of g (Y) which is the minimum value of g (Y) and g (Y) which is the maximum value, g (Y) ^x g (Y)

2 ma is 0.8 or more,

The minimum value of Y is Y 3. OD ≤ Y ≤-0.

min 2 min 2

The maximum direct value of Y is in the range 0.5D ≤Y ≤3.0D

max 2 max 2

(Y and Υ are centered around an arbitrarily selected point light source with f (Υ) value Υ = 0 mm max 2

, The coordinates of both ends to become 0)

The cross-sectional shape in the Y-axis direction of any bowl-shaped convex part 2 is (2N + 1) tilts represented by the following formula:

2

_C is a surface light source element characterized by consisting of regions N to N

twenty two

6 = (Y)) / (2 Ν +1)

2 max min 2

γ shout

J x δ 2

= tan ^_1 (Y / H)

2j j 2

β = sin ((1 / n) sin)

2j 2 2j

γ = sin (1 / n) sin)

2j 2s 2j

a ccf (Y + T -tany) -cosO -cos β ί () cos (a) / cos (Φ — β

2j 2 j 2 2j 2j 2j 2j 2j 2j

Φ = tan ~ ((n -sin / 3) / (n -cos β 1))

2j 2 2j 2 2j N: Natural number

2

j:-an integer from N to N

twenty two

n: Refractive index of the ridge-shaped convex part 2 of the second light control part

2

n: Refractive index of the base material of the second light control unit

2s

a: Width of area j in the Y-axis direction

Φ: slope of the slope with respect to the exit surface of region j

T: Thickness from the incident surface of the second light control unit to the bottom of the bowl-shaped convex part 2

2

I (a): Passes through the first light control unit from the arbitrarily selected point light source and moves in the Y-axis direction.

2 2j

Intensity of light emitted per unit angle in the direction of α along

[0014] Further, the second invention is the surface light source element of the first invention,

The area representing the cross-sectional shape in the X-axis direction of the ridge-shaped convex part 1 is arranged in the order of the 座標 to Ν force Χ axis position coordinates,

And,

Region representing the cross-sectional shape in the Y-axis direction of the ridge-shaped convex part 2 N to N force Y-axis position coordinate

twenty two

The surface light source elements are arranged in order.

[0015] Further, a third invention is the surface light source element of the first or second invention,

The cross-sectional shape in the X-axis direction of the hook-shaped convex part 1 is

A shape approximating the shape of at least one pair of two adjacent regions out of (2N + 1) different regions forming the convex portion with a curve,

And,

The cross-sectional shape in the Y-axis direction of the hook-shaped convex part 2 is

At least one pair of adjacent 2 out of (2N + 1) different regions forming the convex portion

2

The surface light source element is characterized in that the shape of one region is approximated by a curve.

[0016] Further, a fourth invention is the surface light source element according to any one of the first ;! to 3, wherein in the first light control unit,

In the cross-section parallel to the X-axis direction and perpendicular to the Y-axis direction, angle 3 with respect to the front direction

The proportion of light emitted within 0 degrees is 50% or more of the total emitted light,

And, In the second light control unit,

In the cross section perpendicular to the X-axis direction and parallel to the Y-axis direction, the ratio of the light emitted within an angle of 30 degrees with respect to the front direction is 50% or more of the total emitted light. It is a surface light source element.

[0017] Further, the fifth invention is a sheet-like light control member having light control means for controlling a light beam direction along the X axis or the Y axis, which is included in the surface light source element of the present invention.

[0018] Further, a sixth invention is an image display device characterized in that a transmissive display device is arranged in the front direction of the surface light source element of the present invention.

The invention's effect

Hereinafter, the effects of the present invention will be described in detail.

In the present invention, high luminance uniformity and high color uniformity are obtained by replacing the diffusion plate in which fine particles for diffusing light are dispersed with two sheet-like light control members. In the present invention, by providing a hook-shaped convex portion having a suitable shape on the exit surface of the light control member, the use of fine particles that diffuse light is avoided or greatly reduced, and the light use efficiency is improved. Therefore, high brightness can be achieved. In addition, all points on the incident surface of the light control member have a uniform property that controls the direction in which the incident light is emitted in the same way, so that the alignment with the light source is not only advantageous for size change. Is also unnecessary. Further, by making the intensity distribution of the emitted light in the front direction constant, the luminance uniformity in the front direction can be obtained. In addition, the combined functions of the light control member, such as brightness uniformity and brightness enhancement, make it possible to eliminate or reduce the use of other functional optical films, which is advantageous for productivity and thinning. In addition, by arranging a transmissive display device on the exit surface side of these surface light source elements, image display with high color reproducibility, high brightness, brightness uniformity, and color uniformity is achieved. A device is obtained.

[0021] A surface light source element provided by the present invention is a surface light source element having an emission surface parallel to an XY plane parallel to an X axis and a Y axis perpendicular to the X axis. The element includes a plurality of point light sources having a light emitting surface parallel to the XY plane, and two sheet-like light control members. It is possible to obtain brightness uniformity and color uniformity. If the distribution of the position of the intensity of the emitted light in a certain direction is constant on the emission surface of the surface light source element, high luminance uniformity in that direction is achieved. In addition, when many types of point light sources that emit specific colors are used, high uniformity and color uniformity can be achieved by making the above distribution constant for each color.

[0023] The light control member provided in the surface light source element of the present invention obtains luminance uniformity in the front direction by making the intensity of the emitted light in the front direction substantially constant. In addition, with respect to a point light source that emits light of each color, high color uniformity is obtained by obtaining luminance uniformity in the front direction.

[0024] A first invention of the present invention comprises a plurality of point light sources, an exit surface parallel to the XY plane, and two light control members, wherein the plurality of point light sources are X— The surface light source element is periodically arranged in the X-axis and Y-axis directions in a virtual plane parallel to the Y plane, and the light control member is arranged in parallel to the XY plane.

[0025] When the main surface of the light control member and a plurality of point light sources are arranged! /, The virtual plane and the light emission surface of the point light source are parallel to each other. The distribution of the intensity of light incident on the light control member from each point light source is uniform, and the arrangement force of the point light sources is periodic along the axial direction and the Y-axis direction. As a result, the intensity distribution of the incident light as a whole becomes a periodic distribution along the X-axis and Ύ-axis directions, which are the arrangement directions of the point light sources, so that the luminance uniformity is improved. Is easy.

[0026] Of the two light control members, one of the surfaces from which light is mainly emitted is the first light composed of a plurality of hook-shaped convex portions 1 that are orthogonal to the X-axis direction and parallel to the Y-axis direction. The other one of the two light control members that emits light mainly has a surface that is parallel to the X-axis direction and orthogonal to the Y-axis direction. The second light control unit is configured to control the light from the point light source by the first light control unit and the second light control unit, and the distribution of the emitted light in the front direction is made uniform. It becomes possible to do. The first light control unit is composed of a plurality of ridge-shaped convex portions 1 that are orthogonal to the X-axis direction and parallel to the Y-axis direction, and controls light rays along the X-axis direction to transmit light from the point light source X Uniform along the axial direction. On the other hand, the second light control unit is composed of a plurality of ridge-shaped convex portions 2 that are parallel to the X-axis direction and orthogonal to the Y-axis direction, control the light beam along the Y-axis direction, and direct the light from the point light source to Y Uniform along the axial direction. The first light control unit Further, by combining the second light control unit, it is possible to obtain two-dimensional luminance uniformity and color uniformity. Also, by providing two light control members, it is possible to provide the first light control unit and the second light control unit in different light control members, which facilitates the manufacturing process and increases the brightness. This is advantageous in improving color uniformity and achieving improved brightness. The light control member used for the surface light source element of the present invention is suitable for the cross-sectional shape of the hook-shaped convex part 1 and the hook-shaped convex part 2 to achieve uniformity of luminance in the front direction and uniformity of color. It is possible to increase.

[0027] In addition, by arranging the hook-shaped convex portions having the same shape in parallel, the optical properties of the light control member become uniform, so that no precise alignment is required, and a surface light source element or a point light source The surface light source elements can be manufactured with high productivity.

[0028] Light from a point light source is incident on a surface of the light control member on which light is mainly incident. The light control member has a length of one period along the X axis of the plurality of point light sources as D, a center position of the arbitrarily selected point light source as an origin, and a position coordinate in the X axis direction. The position coordinates in the X and Y axis directions are set to Y, and the distance between the light emitting surface of the selected point light source and the first light control unit is represented as H and the light output intensity in the front direction of the exit surface at X. Let f (X) be a function, g (X) = f (X— D) + f (X) + f _i (X + D) (1)

And

In the range of -D / 2≤X≤D / 2,

The ratio of g (X), which is the minimum value of g (X), to g (X), which is the maximum value g (X) / g (X) force s

1 1 mm 1 max 1 mm 1 max

0. 8 or more.

[0029] Further, the light control member has a length D of one period along the Y axis of the plurality of point light sources as D, the light emitting surface of the selected point light source, and the second light control. H, Y

The function that expresses the light intensity in the front direction of the exit surface in 2 2 is defined as f (X).

2

g (X) = f (Y-D) + f (Y) + f (Y + D) (2)

And

The ratio g (Y) / g (Y) of g (Y) which is the minimum value of g (Y) and g (Y) which is the maximum value is

2 2 mm 2 max 2 mm 2 max

0. 8 or more. [0030] In the plurality of point light sources, one period along the X axis or the Y axis refers to a unit of arrangement of light sources arranged repeatedly in the X axis direction or the Y axis direction. The array of point light sources is reproduced by repeating this unit, including all elements related to the uniformity of color and brightness, such as the intensity, relative position, and color of each light source along the direction or Y-axis direction. . Here, however, the arrangement in the X-axis direction and the arrangement in the Y-axis direction are independent. For example, when the point light sources are arranged in an orthorhombic lattice, the period is as shown in FIG.

[0031] The functions g (X) and g (Y) are respectively the same kind of point light sources adjacent to each other in the X-axis direction, Υ

I 2

This is a function that represents the sum of the intensity of light emitted in the front direction for three axial periods.In the configuration where only the same type of point light sources are arranged at equal intervals, three adjacent point light sources are connected to each other! /, It is the sum of all. — The range of D / 2≤X≤D / 2, the range of D / 2≤Y≤D / 2 is the origin.

I I 2 2

It represents one cycle in the X-axis direction and Y-axis direction, respectively, with the point light source selected as the center, and by realizing high brightness and color uniformity in the range of one cycle of the array of point light sources In addition, high luminance and color uniformity can be obtained over the entire emission surface of the surface light source element. In addition, since the light control member uniformly controls the direction of the emitted light at an arbitrary point on the incident surface, the light control member can be controlled within a period of one cycle! /, High! /, By obtaining brightness and color uniformity, the power S can be obtained to obtain high brightness and color uniformity over the entire emission surface of the surface light source element.

[0032] Since the light intensity of the point light source is inversely proportional to the distance, the influence of the light from a remote light source is small. Therefore, by setting the functions g (X) and g (Y) that take into consideration only the light output intensity of the adjacent three-point point light source power into a suitable distribution, the intensity of the emitted light in the front direction can be controlled and corrected.

2

Luminance uniformity in the surface direction and color uniformity can be obtained. Ratio of g (X), which is the minimum value of g (X), to g (X), which is the maximum value, g (X) / g (X) is greater than or equal to 0 ・ 8 and g (Y) mm 1 max 1 mm 1 max 2 Ratio of minimum value g (Y) to maximum value g (Y) g (Y) / g (Y) is more than 0 · 8

2 mm 2 max 2 mm 2 max

By doing so, the intensity of the emitted light in the front direction at an arbitrary position on the exit surface of the surface light source element becomes substantially constant, and it is possible to obtain luminance and color uniformity.

FIG. 10 is a diagram showing f (X) and g (X) of the surface light source element of the present invention in which a point light source is arranged in the X-axis direction as 30 mm, which is shown for (X) in FIG. is there. Arbitrarily selected point light source The center position of the light source is the origin, and the distance [mm] in the X-axis direction is the X coordinate. Figure 10 and Figure 8 shows a similar distribution for f (Y) and g (Y), where Y is the position coordinate.

twenty two

Is possible. Here, f (Y) need not have the same distribution as f (Y).

twenty one

Furthermore, the present inventors have found out the cross-sectional shapes of the hook-like convex part 1 and the hook-like convex part 2 for making the intensity distribution of the emitted light in the front direction substantially uniform. That is, in the present invention, the minimum value X of X is in the range of-3. OD ≤ X ≤-0. 5D, and the maximum value X force S, 0.5D min 1 min 1 max 1

≤X ≤3. The range of OD, and the cross-sectional shape of the saddle-shaped convex part 1 is max 1 according to the following formulas (3) to (9)

(2N +1) regions with different slopes N to N and the minimum Y value Y

1 1 1 min

-3. OD ≤Y 0. 5D range, maximum direct force 0.5D ≤Y ≤3.0D

2 min 2 max 2 max 2, and the cross-sectional shape of the ridge-shaped convex part 2 is expressed by the following formulas (10) to (; 16) (2N +

2

1) A region having different inclinations N to N forces. Of these, hook-shaped convex part 1

twenty two

For the ridge-shaped convex part 2, the area 0 is inclined at 0, that is, parallel to the inclination of the light incident surface of the light control member, and the light incident from directly below can be efficiently emitted in the front direction.

^ o

[0035] δ = (X —X) / (2N +1) (3)

1 max mm 1

X = iX δ (4)

= tan ^_1 (X / H) (5)

li i 1

β = sin ((1 / n) sin a) (6)

li 1 i

γ = sin (1 / n) sin a) (7)

li Is i

a ccf (X + T -tan y) -cosO ^e cos β / \ (a) / cos (a) / cos (0 — β li 1 i 1 li li li 1 li li li li

) (8)

Φ = tan ^_1 ((n -sin / 3) / (n .cos / 3 — 1)) (9)

li 1 li 1 li

N: Natural number

i: -N force, etc. Integer of N

n: Refractive index of the base material of the first light control unit

Is

a: The width of area i in the X-axis direction

li

Φ: Slope inclination with respect to the exit surface of region i

li

τ: thickness from the incident surface of the first light control unit to the bottom of the bowl-shaped convex part 1 I (a): Arbitrarily selected point light source force Unit angle in the direction of α along the X-axis direction

Intensity of light emitted per 1 li li degree

[0036] δ = (Υ-Υ) / (2Ν +1) (10)

2

Screaming δ (11)

2

= tan "(Υ / Η) (12)

2j j 2

^: sin) a) (13)

2j 丄 / n sin

2 2j

γ = sin (1 / n) sin a) (14)

2j 2s 2j

a ccf (Y + T -tany) -cosO -cos β cos

2j 2 j 2 2j 2j 2j (— β

2j 2j

(15)

Φ = tan ^_1 ((n -sin / 3) / (nn --ccooss β / 3 --1)) (16)

2j 2 2j 2 2j

N: Natural number

2

j: integer from -N to N

twenty two

2

n: Refractive index of the base material of the second light control unit

2s

a: Width of area j in the Y-axis direction

Φ: slope of the slope with respect to the exit surface of region j

2

I (α): Passes from the arbitrarily selected point light source through the first light control unit, in the axial direction

2 2j

Intensity of light emitted per unit angle along the direction of

Where α, / 3, γ, Φ, α, / 3, γ, Φ, etc. all have an absolute value of 90 °

1 1 1 1 2 2 2 2

The angle formed clockwise is positive and the angle formed counterclockwise is negative with respect to the reference line.

[0037] Here, the equations (10) to (; 16) for the cross-sectional shape of the ridge-shaped convex portion 2 indicate that I (a) is the first light

2 2j

Except that it is affected by the control unit, it is derived in the same way as equations (3) to (9) of the cross-sectional shape of the hook-shaped convex part 1, and therefore in the explanation of derivation below, the cross-sectional shape of the hook-shaped convex part 1 Describe the description.

First, equation (8) will be described with reference to FIG.

X and X are reduced around an arbitrarily selected point light source whose value of f (X) is X = 0 mm max 1

It is the coordinates of both ends when it fades and becomes virtually zero. Evenly between X and X (2N + 1) minutes When divided, the width δe of each divided element is expressed by equation (3). At this time, the center coordinate X of any element is given by equation (4). The incident angle of the point light source power coordinate X at the position of Χ = 0 with respect to the incident surface of the first light control unit is an angle represented by the equation (5) with respect to the normal direction of the incident surface.

li

[0039] Here, the light is refracted, and the first light control is performed at an angle γ expressed by Equation (7) with respect to the normal direction.

li

Proceed to the inside of the department. When it reaches the bottom of the hook-shaped convex part 1, it is refracted again and travels in the hook-shaped convex part 1 at an angle β shown in Equation (6). Here, the hook-like convex part 1 of the first light control unit and the hook-like convex part li

In this case, light does not refract at the bottom of the hook-shaped convex portion, and γ = β. Of the light traveling through the ridge-shaped convex part 1, it is shown by equation (9)

li li

Only the light that reaches the slope Φ with respect to the outgoing plane is directed in the front direction.

li

[0040] Here, the length of the slope of region i occupied by the slope of angle Φ is b, and the first li li from the slope of region i

Let e be the length of projection in the direction perpendicular to the ray direction in the ridge-shaped convex part 1 of the light control unit

li and the angle of the slope of region i in the cross section parallel to the X-axis direction and the normal direction of the main surface of the first light control unit is The angle formed by (

li

Φ ~ β)

li li

e = b-cos (0 β) (17)

li li li li

It becomes.

[0041] Also, here, the length of the projection onto the plane parallel to the incident plane of the region i occupied by the slope of the angle Φ,

li

If the width of region i in the X-axis direction is a,

It is.

[0042] From Equation (17) and Equation (18),

e = a / οοβ Φ · οο8 (Φ — β) (19)

li li li li li

It becomes.

Here, as shown in FIG. 16, when the width in the X-axis direction of the ridge-shaped convex part 1, that is, the total sum of a is P,

li 1 Enters the base part 31 of the first light control unit at an angle α, passes through the base part, and the hook-shaped convex part 32 li

The proportion of the light 8 directed to the region i out of the light 8 directed to is e / (P−cos / 3).

li 1 li

[0043] On the other hand, the intensity of light per unit area incident on the first light control unit at an angle α, ie, illumination. The degree is proportional to I (a) -cos ² a as described later.

1 li li

In addition, as shown in FIG.

It is proportional to i li li. Therefore, the light intensity per unit area and unit angle incident on the coordinate is itf column in c os ² a / a, and this force, et al., I (α) -cos ² a / cos α, that is, I ( α) · li li 1 li li li 1 li cos is proportional to α. In other words, the light from the point light source is incident on the unit protrusion at the point X = 0.

The ratio of the intensity per unit angle of light incident on the unit convex part at the point of coordinates x = x with respect to the intensity per unit angle of light is I (a) -cosa. Therefore, the light emitted in the front direction

1 li li

± (a) -cos a -e / (P -cos / 3) From equation (19), a / cos -cos (0

1 li li li 1 li li li li

—— β) · Ι (a) ^e cos a / (P ^e cos β).

li 1 li li 1 li

[0044] The light incident on the coordinate is coordinated when the thickness of the substrate of the first light control unit

T-tany), the intensity distribution of the emitted light in the front direction at that time is f (X + Tli 1 i tan γ).

li

[0045] Furthermore, the intensity of the emitted light in the front direction is proportional to the emission intensity of the point light source and the emission ratio in the front direction.

f (X + T-tany) cc _a / αοβΦ · <θ3 (Φ —— β) · Ι () -cos / (Ρ -cos (i

1 i li li li li li 1 li li 1

(20)

li

It is. Therefore,

a · ί (X + T * tany) -cosO ^e cos β / \ (a) / cos a / cos (0 1 β li 1 1 i li li li 1 li li li li

) (twenty one)

It becomes.

[0046] Here, the sum of a can be set such that the width of the ridge-shaped convex portion 1 is P,

li 1

[Number 1]

(twenty three)

[0047] In equation (23), P is a constant, so

a ccf (X + T-tany) -οοβΦ -cos β cos / cos (Φ ― β) li 1 i li li

(8) Is established. The cross section of saddle-shaped convex part 1 starts from region i of width a that satisfies the relationship of equation (8).

li

This is the shape. As already known, since the proportional reduction optical system exhibits almost the same directivity characteristics, the width of the ridge-shaped convex portion can be freely selected.

Here, the relationship between the incident angle to the light control unit 1 and the incident intensity will be described with reference to FIG. Considering a small angle ΔΘ centered on the incident angle Θ from the linear light source to the light control unit 1, if ΔΘ is sufficiently small, the following equations (24), (25), and (26) To establish.

[0049] U = H '. Δ Θ (24)

H '= H / cos θ (25)

V = U / cos θ (26)

Therefore,

Υ = Η · Δ Θ / cos ² d (27)

That is, V is proportional to cos ² Θ. If the intensity of the emitted light from the linear light source within Δ Θ is Ι (Θ), the intensity of the incident light per unit area to the light control unit 1, that is, the illuminance is Ι (Θ) -cos ² Θ Proportional.

Next, equation (9) will be described.

Fig. 7 shows the principle of directing light to the front by the first light controller used in the surface light source element of the present invention. The incident light 7 entering the first light control unit 2 having a refractive index n from the point light source with α is the light control unit 2

1 li

The light 8 is refracted by the incident surface 6 and passes through the inside of the light control unit 2, and the light 8 is refracted by the hook-shaped convex portion 1 on the emission surface side and is emitted to the emission surface side. At this time, the emitted light 9 is emitted in the front direction when the inclination is a desirable angle Φ in the bowl-shaped convex portion 1. The present invention is based on the arrangement.

li

Taking into account the distribution of α and the intensity of incident light 7, the front direction can be adjusted by adjusting the ratio of angle Φ.

It is possible to adjust the distribution of the intensity of the emitted light.

[0051] The inclination Φ of the exit surface for deflecting the incident light 7 in the front direction is equal to the refractive index of the bowl-shaped convex portion 1.

li

, Determined by the incident angle of light to the first light control unit. The angle at which light is incident on the incident surface 6 with respect to the normal of the incident surface 6 is α, and the light is refracted at the incident surface 6 and passes through the inside of the bowl-shaped convex portion 1.

li

The angle formed by the incident light with respect to the normal of the incident surface 6 is / 3, and the light traveling inside the ridge-shaped convex portion 1

li

The angle formed with respect to the normal of the exit slope of the hook-shaped convex part is ε, and the light is refracted at the exit slope,

li

The directional force on the exit surface and the angle formed with respect to the normal to the slope of the light is ω, and Let the ratio be. At this time, let Φ be the angle of the slope of the ridge-shaped convex portion so that the light emitted from the ridge-shaped convex portion travels in the front direction.

li

[0052] At this time, the following relationship is established.

Φ = β-ε (28)

li li li

— N ^e sin ε = — sin o = sinO (ω = — Φ) (29)

1 li li li li li

From Equation (28) and Equation (29),

— N -sin (/ 3 Φ) = sinO (30)

1 li li li

n · (sinO ^e cos β — cosO ^e sin β) = sinO (30),

1 li li li li li

Dividing both sides of equation (30) by cos (sin / cosO) = tanO)

li li li li

n · (tanO -cos β sin β) = tanO (30),

1 li li li li

Therefore, Φ is expressed by the following equation.

li

Φ = tan ^_1 (n / sin / 3) / (n -cos β --1) (9)

li 1 li li li

From Equation (6) 'and Equation (9),

Φ = tan {sin /, n -cos (sin ((1 / n) sin)) 1)}

li li 1 1 li

(30), ...

[0053] a, n, and Φ have such a relationship that the refractive index n of the bowl-shaped convex part 1 and the slope of the bowl-shaped convex part 1

li 1 li 1

By the inclination Φ, light having a desired incident angle α can be emitted in the front direction.畝

li li

For each region i of the convex-shaped convex part 1, by satisfying equation (9), it is incident on the light control part 1 at an angle α

li

The emitted light can be emitted from the region i of the bowl-shaped convex portion 1 in the front direction.

As described above, since the same theory can be applied to the light control unit 1 and the light control unit 2, a similar expression can be derived for the light control unit.

[0055] However, the intensity of light emitted per unit angle in the direction of α along the Y-axis direction from an arbitrarily selected point light source is affected by the first light control unit. This effect is explained below.

[0056] As an example, the point light source force is incident on the first light control unit with an inclination α = 0 along the X-axis direction.

li

Think of the light. Of the light incident on the first light control unit, the light beam incident on the region i of the bowl-shaped convex portion 1 is shown in FIG. The angle between the normal of the area i slope and the incident light direction is If it is not tilted in the front direction along the Y-axis direction (α = 0), η

2j li

An angle ε with respect to the normal of the slope of region i in a plane parallel to the Y axis

When li shigu ε is smaller than the total reflection angle, it refracts and exits from region 1. On the other hand, Υ axis li

When the frontal force is tilted along the direction ( _α ≠ 0), 7]> ε and the incident light

2j li li

If the line direction is greatly tilted in the Y-axis direction, total reflection will not occur even if ε is smaller than the total reflection angle.

li

May occur.

[0057] Therefore, when the tilt is greatly tilted along the Y-axis direction, the probability that the first light control means reflects to the point light source increases, and the point light source moves along the Y-axis direction. The intensity of light radiated per unit angle in the direction of α through the first light control means

2)

Attenuates as α increases. In the second light control means, the first light control hand

2)

In order to control the ray direction after being affected by the step along the axis, I (a) is

2 2j

It is necessary to make the distribution in the angular direction after passing through the light control means.

[0058] From the above description, I (a) is obtained from the arbitrarily selected point light source by α along the Y-axis direction.

2 2j A decays at a large angle with respect to the intensity of light emitted per unit angle in the 2j direction.

2)

Distribution. This attenuation can be approximated by an appropriate function, for example (cos a) ^m and I (

2j 2 a) from a point light source arbitrarily selected along the Y-axis direction in the direction of α around the unit angle

twenty two)

It can be the product of the intensity of the emitted light and (cos a) ^m . Where m is 0 · 5 to 1

2)

2 is appropriate.

[0059] As described above, in the intensity distributions f (X) and f (Y) of the emitted light in the desired front direction, which is an important factor for determining the ridge-shaped protrusion 1 and the ridge-shaped protrusion 2 In light control unit 1

1 2

The slope Φ of area i and the width a in the X axis direction occupied by this, the slope of area j in the light control unit 2 Φ li li 2j and the width a in the Y axis direction occupied by this, the arrangement of the point light sources and the refractive index of the light control unit Configuration such as

2)

Selected based on

[0060] A second invention of the present invention is the surface light source element of the first invention, wherein a region N to N force axis position coordinates representing a cross-sectional shape of the hook-shaped convex portion 1 in the X-axis direction are provided. The regions N to N that are arranged in order and that represent the cross-sectional shape in the Y-axis direction of the bowl-shaped convex part 2 are the Y-axis.

twenty two

It is a surface light source element characterized by being arranged in the order of position coordinates! /. At this time, inflection points are present in the cross-sectional shape in the X-axis direction of the unit bowl-shaped protrusion 1 and the cross-sectional shape in the Y-axis direction of the unit bowl-shaped protrusion 2. The entire convex part is substantially convex. When there are many inflection points, the light reaches the region on another convex part before it reaches the region on the desired convex part, and the direction of the light beam is changed by reflection or refraction, and the light emission direction is controlled. May be difficult. In addition, a shape that does not have an inflection point has a simpler shape than a shape that has an inflection point.

[0061] A third invention of the present invention is the surface light source element of the first or second invention, wherein the cross-sectional shape in the X-axis direction of the bowl-shaped convex portion 1 forms the convex portion (2N + 1) A shape obtained by approximating the shape of at least one pair of two adjacent regions out of a plurality of regions with different inclinations by a curve, and the cross-sectional shape in the Y-axis direction of the bowl-shaped convex portion 2 is the convex shape (2N + 1) slopes forming part

2

The surface light source element is characterized in that the shape of at least one pair of two adjacent regions among the different regions is approximated by a curve. In the first invention, the hook-shaped convex portion 1 is a force composed of (2N + 1) slopes of angle Φ.

li

It shows a shape that approximates the shape of at least one pair of two adjacent areas by a curve, and the hook-like convex part 2 of the first invention is composed of (2N + 1) slopes of angle Φ. The hook-shaped convex part of the third invention

2 2j

Figure 2 shows a shape that approximates the shape of at least one of the two adjacent regions with a curve. By approximating with a curve, the intensity distribution of outgoing light and the angular distribution of outgoing light in the front direction become smoother, which is desirable. In addition, because it is easier to shape, it is advantageous in production and desirable. Further, since the joint portion in the region is not sharp and has a shape, it is difficult to cause damage, so it is preferable that the light emission direction change due to the breakage of the joint portion in the region and unnecessary scattering hardly occur.

[0062] A fourth invention of the present invention is the surface light source element of any of the first to third inventions, wherein the first light control unit is parallel to the X-axis direction and orthogonal to the Y-axis direction. In the cross section, the ratio of the light emitted within an angle of 30 degrees with respect to the front direction is 50% or more of the total emitted light, and the second light control unit is orthogonal to the X-axis direction and Y In the cross section parallel to the axial direction, the surface light source element is characterized in that the proportion of light emitted within an angle of 30 degrees with respect to the front direction is 50% or more of the total emitted light. Since the surface light source element emits a relatively large proportion of light emitted in the front direction, bright illumination can be efficiently obtained in applications such as a television or a personal computer monitor that mainly observe the light exit surface in the front direction. In the first light control unit, in a cross section parallel to the X-axis direction and perpendicular to the Y-axis direction. In this case, the ratio of the light emitted within a range of an angle of 30 degrees or less with respect to the front direction can be adjusted by adjusting the angle of the inclined surface of the hook-shaped convex part 1 of the first light control part, In the second light control unit, the ratio of light emitted within a range of an angle of 30 degrees or less with respect to the front direction in the cross section orthogonal to the X-axis direction and parallel to the Y-axis direction is It can be adjusted by adjusting the angle of the slope of the hook-like convex part 2 of the second light control part. The angle of the slope of the bowl-shaped convex part 1 can be adjusted by adjusting the width of X to X, and the front max mm

The angle of the slope of the recording-like convex portion 2 can be adjusted by adjusting the width of Y to Υ.

max mm

[0063] A fifth invention of the present invention is a sheet-like shape having a light control means for controlling the direction of the light beam along the X-axis or Y-axis, which is included in the surface light source element of any of the first to fourth inventions. This is a light control member. The light control member includes a first light control unit and a second light control unit that control a light beam direction, and light incident mainly from a light incident surface of the light control member is a first light control unit. Part of the light is reflected by the means or the second light control means, and part of the light is transmitted. This function improves the brightness uniformity and color uniformity of the emitted light. The light passing through the light incident surface of the light control member mainly refracts at the incident surface, passes through the light control member, and reaches the hook-shaped protrusion 1 and / or the hook-shaped protrusion 2. The light incident on the hook-shaped convex part 1 is refracted along the X-axis direction according to the slope of the slope of each region in the hook-shaped convex part 1, and the light reaching the hook-shaped convex part 2 Refracts along the Y-axis according to the slope of the slope in each region in 2. The light that reaches the region of an appropriate angle is emitted in the front direction. Therefore, by appropriately selecting the ratio of the areas of the ridge-like convex part 1 and the ridge-like convex part 2 having different inclinations, the luminance distribution of the emitted light in the front direction at a point on an arbitrary emission surface is made constant. It is possible to do.

[0064] A sixth invention of the present invention is an image display device configured by disposing a transmissive display device in the front direction of the surface light source element of any one of the inventions !! The surface light source element is a uniform surface light source element having a uniform intensity distribution of emitted light in the front direction, and the ratio of the intensity of emitted light in the front direction can be increased. By disposing a transmissive display device, it is possible to display high-quality images because of high brightness and color uniformity with good color reproducibility. Here, the image display device of the present invention is a display module in which a surface light source element and a display element are combined, and further, this display module is used. It is a device having at least an image display function, and includes a television, a personal computer monitor, and the like.

[0065] The intensity distribution of outgoing light in the front direction can be evaluated by measuring the distribution of front luminance. The distribution of front luminance is the same as the luminance meter is moved at regular intervals in the X-axis direction and Y-axis direction while keeping the distance between the luminance meter and the measurement point on the exit surface of the surface light source element constant. ¾ Measure. In addition, the ratio of the outgoing light in the front direction is first measured along the cross section parallel to the X axis direction and perpendicular to the Y axis direction, and along the cross section perpendicular to the X axis direction and parallel to the Y axis direction. Measure the point by changing the angle while keeping the distance between the luminance meter and the measurement point constant. The brightness value obtained for each angle is converted into energy, and the ratio of light emitted within an angle of 30 degrees with respect to the front direction in the cross section parallel to the X axis direction and perpendicular to the Y axis direction, and the X axis direction Calculate the proportion of light emitted within an angle of 30 degrees with respect to the normal direction in a cross section orthogonal to the Y-axis direction.

[0066] In the present invention, in the direct-type surface light source element, the intensity distribution of the emitted light in the front direction where the light use efficiency is high is made constant, thereby eliminating the light / dark difference due to the image of the point light source. Provided is a surface light source element with improved brightness uniformity and color uniformity in the front direction. Also provided is a surface light source element capable of obtaining high front luminance with a large proportion of outgoing light in the front direction. In addition, by approximating the ridge-like convex part 1 and the ridge-like convex part 2 of the light control member with curves, it is possible to obtain a smooth intensity distribution of outgoing light in the front direction and a desired smooth outgoing light angle distribution. . In addition, the use of other functional optical films can be eliminated or reduced, which is advantageous for productivity and thinning. Furthermore, since the light control member provided in the surface light source element of the present invention performs the same optical control on the incident light at all locations, the strict alignment between the point light source and the light control member is achieved. It is unnecessary and can respond immediately to changes in the display size and the number and arrangement of point light sources, making it possible to manufacture surface light source elements with high productivity. The present invention also provides an image display apparatus using the surface light source element.

Brief Description of Drawings

[0067] FIG. 1 is a diagram showing a preferred example of a surface light source element of the present invention.

2 is a diagram showing the relationship between the position of a point light source in a plane parallel to the X axis and perpendicular to the Y axis and the intensity distribution of emitted light in the front direction of the surface light source element of FIG.

[Figure 3] A flat plane parallel to the X axis and perpendicular to the Y axis when three adjacent point light sources are arranged It is a figure which shows the intensity distribution of the emitted light to the position of the point light source in a surface, and each front direction.

Fig. 4 is a diagram showing an example of an array of a plurality of point light sources in the surface light source element of the present invention. Fig. 5] An incident angle of light from the point light source on a plane parallel to the X axis and perpendicular to the Y axis. FIG. 7 is a diagram showing a relation between a, the slope Φ of the slope of the region i in the bowl-shaped convex portion 1, and the width a of the region i in the X-axis direction.

6] A diagram showing the relationship between the incident angle of light and the incident intensity on the light control member.

FIG. 7 is a diagram showing the principle of deflecting light in the front direction with the surface light source element of the present invention.

FIG. 8 is a diagram showing an example of an intensity distribution in the X-axis direction of light emitted from a single point light source in a plane direction in a cross section parallel to the X-axis and perpendicular to the Y-axis. .

[Fig. 9] The intensity distribution in the X-axis direction of the light emitted from one point light source in the front direction in a cross section parallel to the X-axis and perpendicular to the Y-axis is different from that in Fig. 8. It is a figure which shows an example

FIG. 10 is a diagram showing f (X) of the surface light source element shown in FIG. 8 and g (X) corresponding thereto. 11] FIG. 10 is a diagram showing f (X) of the surface light source element shown in FIG. 9 and g (X) corresponding thereto.

FIG. 12 is a diagram showing the traveling direction of light when light from a point light source is incident on the incident surface of the light control member of Comparative Example 2 vertically.

13] A diagram showing the traveling direction of light when light from a point light source is incident on the incident surface of the light control member of Comparative Example 2 from an oblique direction.

14] A diagram showing a configuration of a surface light source element of Comparative Example 1 using a diffusion plate in which normal fine particles are dispersed.

15] This is a diagram showing the intensity distribution of the emitted light from the point light source in the front direction in a cross section parallel to the X axis and perpendicular to the Y axis.

FIG. 16 is a graph showing the ratio of directional force and luminous intensity to region i out of the light traveling toward bowl-shaped convex part 1 at an angle of 0.

li-Sen 17] It is a diagram showing an angle Δα at which a point light source is viewed at a point of coordinate X in a cross section parallel to the X axis and perpendicular to the Y axis. [Fig.18] Relationship between the position of a point light source on a plane parallel to the X axis and perpendicular to the Y axis, and the intensity distribution of the emitted light in the front direction, for a surface light source element using three types of point light sources FIG.

FIG. 19 is a diagram showing the influence of the first light control unit on the intensity of light emitted per unit angle in the direction of α along the axial direction.

FIG. 20 is a table showing configurations and results of examples and comparative examples.

Explanation of symbols

1: Point light source

11: Red LED

12: Blue LED

13: Green LED

2: Light control member

3: First light controller

31: Base material part in the first light control unit

32: ridge-shaped convex part 1

32a: Slope of area i of bowl-shaped convex part 1

4: Second light control unit

5: Reflector

6: Main light incident surface of the first light control unit

7: Light traveling through the base material of the light control member

8: Light traveling inside hook-shaped convex part 1 or hook-shaped convex part 2

9: Light emitted from the light control member

10: Prism sheet

11: Light incident on region i of bowl-shaped convex part 1 with α = 0 and α = 0

li 2j

12: Light that is refracted and emitted from region i of bowl-shaped convex part 1

13: Light incident on area i of bowl-shaped convex part 1 with α = 0 and α ≠ 0

li 2j

14: All of the light incident on region i of α-shaped convex part 1 with α = 0 and α ≠ 0 on the slope of region i

li 2j

Reflected light D _i: Period of array of point light sources in the X-axis direction

D: Period of array of point light sources in the Y-axis direction

2

H: Distance from the light emitting surface of the point light source to the incident surface of the first light control member

H: Distance from the light emitting surface of the point light source to the incident surface of the second light control member

2

f (X): Intensity distribution of light emitted from any point light source in the front direction from the first light controller on a plane parallel to the X axis and perpendicular to the Y axis

f (Y): of light from any point light source in a plane perpendicular to the x axis and parallel to the Y axis

2

Intensity distribution of light emitted from the second light control unit in the front direction

N, N: natural number

1 2

n: Refractive index of bowl-shaped convex part 1

n: Refractive index of the base material of the first light control unit

Is

n: Refractive index of bowl-shaped convex part 2

2

n s: refractive index of the base material of the second light control unit

2

X: X coordinate in the positive direction when f (X) is 0

max 1

X: X coordinate in the negative direction when f (X) is 0

mm 1

Y: Y coordinate in the positive direction when f (Y) is 0

max 2

Y: Y coordinate in the negative direction when f (Y) is 0

mm 2

g (X): f (XD) + f (X) + f (X + D); Any point light source and adjacent point light sources on a plane parallel to the X axis and perpendicular to the Y axis Intensity distribution of light emitted from the first light control unit in the front direction

g (Y): f (Y-D) + f (Y) + f (Y + D); in a plane perpendicular to the X axis and parallel to the Y axis

2 2 2 2 2 2

Intensity distribution of light emitted from the first light control unit in the front direction from light from an arbitrary point light source and adjacent point light sources on both sides

g (X): Minimum value of g (X) between X and X

1 min mm max 1

g (X): Maximum value of g (X) between X and X

1 max min max 1

g (Y): Minimum value of g (Y) between Y and Y

mm mm max

g (Y): Maximum value of g (Y) between Y and Y

2 max min max 2

δ: Small interval in the X-axis direction that satisfies δ = (X -X) / 2N + 1 6: δ = (Υ -Υ) / 2Ν + 1 Small interval in the Υ axis direction

2 2 max min 2

Φ: slope of the ridge-shaped convex part 1 with respect to the exit surface of the region i

li

Φ: slope of the ridge-shaped convex part 2 with respect to the exit surface of the region j

2j

X: X coordinate center value of each element when X to X are equally divided by (2N + 1)

1 mm max 1

Y: Center value of Υ coordinate for each element when Υ ~ Υ is equally divided by (2Ν + 1)

j min max 2

a: width in the X-axis direction of the region i in the ridge-shaped convex portion 1 of the first light control unit

li

a: Width in the Y-axis direction of the region j in the ridge-shaped convex part 2 of the second light control part

T: Thickness from the incident surface of the first light control unit to the bottom of the bowl-shaped convex part 1

2

I (a): Arbitrarily selected point light source force Unit angle in the direction of α along the X-axis direction

1 li li

Intensity of light emitted

I (α): arbitrarily selected point light source force A unit angle in the direction of α along the Υ axis direction

2 2j 2j

Intensity of light emitted

a: From the point light source to the first light controller in a plane parallel to the X axis and orthogonal to the Y axis

The angle that the light from the point light source enters and exits from area i with respect to the front.

a: From a point light source to the second light control unit in a plane perpendicular to the X axis and parallel to the Y axis

2j

The angle that the light from the point light source enters and exits from area j with respect to the front.

β: li from the point light source to the first light controller in a plane parallel to the χ axis and perpendicular to the Υ axis

The angle formed by the direction of the light beam incident on and exiting from region i with respect to the front direction in the ridge-shaped convex part 1

β: From a point light source to the second light control unit in a plane perpendicular to the axis and parallel to the axis

2j

The angle formed by the direction of the light beam incident on and exiting from area j inside the ridge-shaped convex part 2 with respect to the front direction.

7: li from the point light source to the first light controller in the plane parallel to the x-axis and perpendicular to the Y-axis

The angle formed by the direction of the light incident on the substrate of the first light control unit with respect to the front direction. 7: From a point light source to the second light control unit on a plane perpendicular to the X axis and parallel to the Y axis

2j

The angle formed by the direction of the light incident on the substrate of the second light control unit with respect to the front direction.

b: Length of the slope of region i in a plane parallel to the X axis and perpendicular to the Y axis

li

b: Length of slope of region j in a plane perpendicular to X axis and parallel to Y axis

e: li from the point light source to the first light control unit in a plane parallel to the X axis and perpendicular to the Y axis

The length of the projection of the slope of region i in the direction perpendicular to the direction of the light beam inside the first light control unit for the light that enters and exits from region i.

: The angle of the slope of region i in the plane parallel to the χ axis and perpendicular to the Υ axis is

Angle formed with respect to the angle perpendicular to the ray direction in part 1

: The normal of the slope of region i in the ridge-shaped convex part 1 and the direction of light incident on the slope of region i and li

Angle

Θ: The light direction from the point light source that is incident on the first light control unit from the point light source and exits from the exit surface on the plane parallel to the X axis and perpendicular to the Y axis is relative to the front direction. Angle

Δ θ: Angle formed by a small area centered on the light with the incident angle Θ on the plane parallel to the X axis and perpendicular to the Y axis.

H ′: a point on the incident surface of the first light control unit through which light emitted from the point light source at an angle (θ−ΔΘ) passes in a plane parallel to the X axis and perpendicular to the Y axis, and the point light source The length of the line segment connecting to the center of the projection onto the straight line through which the light emitted from the point light source and the angle Θ passes (incident at the first light control unit through which the light emitted from the point light source at the angle Θ passes. Approximately equal to the distance between a point on the surface and the center of the point light source)

V: In the plane parallel to the X axis and perpendicular to the Y axis, the incident light from the point light source is centered on the incident angle Θ. length

U: In the plane parallel to the X-axis and perpendicular to the Y-axis, the incident light from the point light source is centered on the incident angle Θ. Projection to an angle perpendicular to the incident angle Θ ε: Light in the ridge-shaped convex portion 1 of light incident on the first light control unit from the point light source on the plane parallel to the X-axis and perpendicular to the Y-axis toward the region i of the ridge-shaped convex portion 1 The angle formed by the ray direction with respect to the normal of the slope of area i

ω: Light incident on the first light control unit from the point light source on the plane parallel to the Χ axis and orthogonal to the Υ axis, and emitted from the ridge projection 1 to the region i of the ridge projection 1 Angle formed by ray direction with respect to normal of slope in area i

P: Width of bowl-shaped convex part 1 in a plane parallel to the x axis and perpendicular to the Y axis

Δ a: Angle at which the point light source is viewed from the coordinate X on a plane parallel to the X axis and perpendicular to the Y axis

L (X): Minimum luminance value in front of the surface light source element in one period along the X axis

L (X): Maximum luminance in the front direction of the surface light source element in one period along the X axis

L (Y): Minimum luminance value in front of the surface light source element in one period along the Y axis

L (Y): Maximum value of luminance in the front direction of the surface light source element in one cycle along the Y axis z: The cross-sectional shape of the hook-shaped convex part 1 or the hook-shaped convex part 2 when the vertex is the origin, Height coordinate

P: Position coordinate in the X-axis direction or Y-axis direction of the cross-sectional shape of hook-shaped convex part 1 or hook-shaped convex part 2 when the top is the origin

BEST MODE FOR CARRYING OUT THE INVENTION

An example of the best mode for carrying out the present invention is shown in FIG. One of the normals of the X—Y plane parallel to the X axis and the Y axis perpendicular to the X axis is the front direction, and at least an emission surface parallel to the X—Y plane, a plurality of point light sources, 2 A plurality of sheet-like light control members, wherein the plurality of point light sources are periodically arranged in the X-axis and Y-axis directions in a virtual plane parallel to the XY plane, and are arranged on the XY plane. A light emitting surface that is parallel to the light control member, the light control member is disposed in parallel to the XY plane and in front of the plurality of point light sources, and is disposed on the front direction side of the light control member. A first light control unit comprising a plurality of convex protrusions 1 orthogonal to the X-axis direction and parallel to the Y-axis direction on the emission surface side of the two light control members Second light consisting of a plurality of hook-shaped convex portions 2 parallel to the X-axis direction and orthogonal to the Y-axis direction on the emission surface side of the two light control members System It is a surface light source element with a control unit!

[0070] The point light source of the present invention is not particularly limited, but an LED or the like can be used. There are white LED, red, blue, green, and other color LEDs, but only white is used, and each color LED is arranged periodically. In addition, a plurality of light sources having the same color may be arranged within one period depending on the color required on the emission surface.

The shorter the period D and D of the point light source in the X-axis and Y-axis directions, the brightness uniformity and color

1 2

This is desirable because it provides a high brightness that is not too uniform. However, if the period is too short, the number of point light sources increases, resulting in an increase in power consumption and a problem of heat generation. The period in the X-axis direction and Y-axis direction is preferably 7mm to 70mm. More desirably, it is 15 mm to 50 mm.

FIG. 15 is a diagram showing the intensity of emitted light in the front direction and the position of the point light source in a cross section parallel to the X axis direction and perpendicular to the Y axis direction when the point light sources are arranged. As shown here, in a surface light source element having an array of a plurality of point light sources 1, the intensity of emitted light in the front direction (up in the figure) is the portion directly above each point light source 1. And the point light source adjacent to the directly above portion and the intermediate position portion of the point light source (portion going diagonally upward from the point light source) are greatly different. This indicates that in the surface light source element of the present invention, the intensity of the incident light on the surface on which the light is mainly incident on the light control member is greatly different between the portion directly above the respective point light sources 1 and the obliquely upper portion. ing. The difference in strength is the same in the cross section orthogonal to the X-axis direction and parallel to the Y-axis direction.

FIG. 2 is a diagram showing the relationship between the position of the point light source and the intensity of the emitted light in the front direction in a cross section parallel to the X axis direction and orthogonal to the Y axis direction of the surface light source element of FIG. . A similar intensity distribution is shown even in a cross section orthogonal to the X-axis direction and parallel to the Y-axis direction. Thus, in the surface light source element of the present invention, the intensity distribution of the emitted light in the front direction is almost constant. Uniformity of luminance in the surface direction and uniformity of color can be obtained.

[0073] FIG. 18 shows the position of the point light source when three different types of point light sources in the cross section parallel to the X axis direction and perpendicular to the Y axis direction are arranged for three periods in the Y axis direction. FIG. 6 is a diagram showing the intensity distribution of outgoing light in the respective frontal directions. For each type of point light source, if the sum of the three periods is almost constant, the brightness and color in the high front direction Uniformity is obtained. As shown in FIG. 2, the surface light source element of the present invention has a substantially uniform intensity distribution of the emitted light in the front direction, as shown in FIG. Is obtained.

[0074] In FIG. 8, the light emitted in the front direction by light from any one point light source of the surface light source element of the present invention in which point light sources are arranged in the X-axis direction with D = 30 mm, An example of the distribution in a cross section parallel to the X axis direction and perpendicular to the Y axis direction is shown. The light emitted in the front direction from the light from one point light source is in the range of X to X. Gently as shown in Figure 8.

mm max

In the case of showing attenuation, for example, the value of X when the value of f (X) is 1/100 of the maximum value can be substituted. The values of f (X) for determining X and x must be the same.

mm max 1

If it is less than 1/20 of the desired maximum value, it is more desirable that it is 1/100 of the problem. In Fig. 8, X = — 3D, X = 3D, and f (X) = f (X) and the maximum of ()

mm 1 max 1 1 mm 1 max 1

1/100 or less of the value. Since the intensity of the emitted light in the front direction of the surface light source element obtained from such a distribution is not strictly determined only by the sum of the point light sources for three adjacent periods, g (X) is constant. It is desirable that g (X) near the center where X = 0 is slightly higher than the surroundings. Similarly, g (Y) near the center where Y = 0 is compared with the surroundings.

2

It is desirable to be a little expensive.

[0075] The ratio of g (X), which is the minimum value of g (X), to g (X), which is the maximum value, g (X) / g

1 1 mm 1 max 1 mm

When (X) is greater than or equal to 0.8, the brightness is uniform along the X-axis direction, and g (Y)

The ratio of g (Y) which is the minimum value of 1 max 2 and g (Y) which is the maximum value is g (Y) / g (Y)

2 min 2 max 2 mm 2 max ο

Since the luminance is uniform along the Y-axis direction when it is 8 or more, a surface light source element with high luminance uniformity can be obtained. g (X) / g (X) and g (Y) / g (Y) values are 0

1 mm 1 max 2 mm 2 max

More than 85 is more suitable, and in this case, a surface light source element with higher luminance uniformity and color uniformity can be obtained, and a transmissive liquid crystal panel or the like can be provided in front of the exit surface of the surface light source element. When the image display device is arranged in the direction, a high screen quality can be obtained. In order to obtain higher screen quality, 0.90 or higher is desirable.

In FIG. 9, as in the case of FIG. 8, D = 30 mm and point light sources are arranged in the X-axis direction, and the emitted light in the front direction in the surface light source element of the present invention using another light control member Shows an example of the distribution in a cross section perpendicular to the X-axis direction and parallel to the Y-axis direction. X in this example = — DX = D. Depending on the shape of the ridge-shaped convex part 1, light above a certain incident angle mm 1 max 1

Since the light does not travel in the front direction, the distribution of the intensity of the emitted light suddenly decreases at a portion away from the point light source to some extent. In such a distribution, the intensity distribution of the emitted light in the front direction is determined by the sum of the three adjacent periods, so it is most desirable that g (X) be constant. At this time, light is emitted in the front direction in the range of X X, and its distribution is f (X).

mm max

The Figure 8 shows X = — 3D X = 3D and Figure 9 shows X = —D X

x 1 mm 1 ma The slope of the ramp is limited because the width of the ridge-shaped projection is limited.

The distribution of the outgoing light in the front direction is determined by the distribution of the degree Φ. X-axis direction of hook-shaped convex part 1

The cross-sectional shape in the direction has a slope angle that directs light with low energy incident from an oblique direction to the front as shown in Fig. 8. Only the light incident in the range of D <X <D without the angle Φ

li 1 1

Frontal brightness is improved by the hook-shaped convex part 1 formed by the angle Φ to be directed. X x like this

Reducing the width of li mm m effectively reduces the front ax by deflecting stronger light to the front effectively.

This has the effect of increasing the ratio of outgoing light in the direction.

[0077] On the other hand, increasing the width of X X directs light from a distant point light source to the front.

min max

This has the effect of increasing the ratio of outgoing light in the front direction. Therefore, in order to increase the front brightness, it is desirable that the width of XX is in an appropriate range. Desirable X

mm max max

The width of X varies depending on f (X) .For example, the intensity of the emitted light is more than half of the maximum value mm 1

The X range can be used as a guide. If this range is large, the width of X x

max mm If it is desirable to take a relatively large value, it is desirable to take a smaller value. Thus, the front brightness can be increased by suitably determining the width of X x.

max mm

FIG. 11 shows g (X) of the surface light source element shown for f (X) in FIG. As already shown, g (X) is one period of the point light source—if it is constant in the range D / 2≤X≤D / 2, high brightness and color uniformity are obtained in the front direction. And XX is optimal

mm max

Since the high energy light near the point light source is deflected to the front, the brightness in the front direction becomes higher.

[0079] Similarly, in the saddle-shaped convex part 2, g / 2 (X) is one period of the point light source D / 2≤

twenty two

If it is constant within the range of Y≤D / 2, high brightness and color uniformity can be obtained in the front direction.

2 When Y and Υ are optimal, light with high energy near the point light source is

Since it is deflected, the luminance in the front direction can be increased. Υ ~ の appropriate

The mm max range is the same as that of the ridge-shaped convex part 1, for example, the range of Y where the intensity of the emitted light is 1/2 or more of the maximum value, and the range of Υ to を can be set according to this range. Want to take

min max

Yes.

[0080] In the bowl-shaped convex portion 1, the arrangement order of the regions N to N does not necessarily have to be along the X axis. However, in this case, there is an inflection point in the convex portion having a cross-sectional shape in the X-axis direction of the bowl-shaped convex portion 1 depending on the arrangement order of the regions, and the angle that deflects the light incident at an angle α to the front.

li

Before reaching the saddle-shaped convex part 1 of degree Φ, it reaches a slope of another angle, and refraction or reflection is li

Therefore, the direction of the light beam changes and does not reach the slope of angle Φ, or at an undesirable angle.

li

Reaching the slope with an angle Φ makes it difficult to control the direction of light emission.

Performance may be insufficient. -When the area force axes of N to N are arranged in the order of the position coordinates, the shape of the convex part usually has no inflection point, and the entire convex part is substantially convex. Such a convex portion is advantageous in that it is easy to control the direction of the light beam, in which light does not normally reach the region on the desired convex portion and the direction of the light beam changes due to reflection or refraction.

[0081] Also in the hook-shaped convex portion 2, the arrangement order of the regions N to N is not necessarily along the X axis.

twenty two

There is no need. However, in this case, there is an inflection point in the convex part that is a cross-sectional shape in the X-axis direction of the bowl-shaped convex part 2 due to the arrangement order of the regions, and the angle that deflects the incident light at an angle α to the front angle. Before reaching the ridge-shaped convex part 2 of Φ, it reaches a slope of another angle and is refracted or reflected

2j

Changes the beam direction and does not reach the slope of angle Φ, or is an undesirable angle

2j

And reaching the slope of angle Φ, it becomes difficult to control the light emission direction,

2j

Performance may be insufficient. -N to N area force lines are arranged in order of position coordinates

twenty two

In general, the shape of the convex portion does not have an inflection point, and the entire convex portion is substantially convex. In the case of such a convex part, it is easy to control the direction of the light beam, which is usually advantageous because the light reaches the region on the desired convex part and the direction of the light beam does not change due to reflection or refraction.

[0082] Also, the width a force (X + T. Tan / 3)-οοβ Φ-cos / 3 in the X-axis direction of each region of the bowl-shaped convex part 1

li 1 i 1 li li

It is a feature of the surface light source element of the present invention that it is proportional to / cos a / αο ₈ (Φ-β).

The preferred width may deviate slightly due to the height from the bottom to the surface of the protrusion. There is no significant impact. The effect of the height of the surface from the bottom of the convex part is not significant for the hook-shaped convex part 2 as well.

[0083] Although it is desirable that the thicknesses T and T of the light control member are thin,

1 2

In the surface light source element, since a space is provided between the light source and the light control member, it is desirable that the light control member arranged closest to the light source has a thickness that does not bend or deform. . The light control member arranged on the most light source side varies depending on the size of the surface light source element, and the thickness is preferably 0.5 mm to 5 mm. If it is thinner than this, the light control member will bend or deform, the point light source will come into contact with the light control member, and the appearance quality will deteriorate. If it is thicker, the surface light source element becomes thicker and the weight increases. More desirably, the thickness is 1 mm to 4 mm, and more preferably 1.5 mm to 2.5 mm. In this range, the strength is maintained, and it is possible to suppress an increase in manufacturing cost due to an increase in the amount of base material used per main surface area.

[0084] Also, N and N determine the number of regions into which the ridge-shaped protrusion 1 and the ridge-shaped protrusion 2 are divided.

1 2 is preferably 2 or more. When N and / or N is large,

1 2

The convex portion in the cross-sectional shape in the X-axis direction and / or the cross-sectional shape in the Y-axis direction of the bowl-shaped convex portion 2 has a complicated shape having many inclinations. When the number of inclinations is large, the outgoing light in the front direction can be accurately controlled, and the intensity distribution of the outgoing light in the front direction is highly uniform. From the aspect of accuracy, N and N are better, but if it is too large, the shape becomes complicated.

1 2

Making it difficult. In terms of ease of fabrication, N and N force must be less than

1 2

Desirably, 10 or less is more desirable.

[0085] At least one pair of regions forming the protrusions is adjacent to the cross-sectional shape in the X-axis direction of the hook-shaped convex portion 1 and / or the cross-sectional shape in the Y-axis direction of the hook-shaped convex portion 2. The shape of the area may be approximated by a curve. Furthermore, the shape of three or more adjacent regions may be approximated by a curve. The shape of the entire convex portion may be approximated by a curve. Approximating the shape of many areas with a curve, curves the shape of adjacent areas such as smoothing the intensity distribution of outgoing light in the front direction and the angular distribution of outgoing light, shaping shading, and preventing damage. The effect of approximating with is more desirable and desirable. As an approximation method to a curve, there are no particular limitations, and the well-known least square method, spline interpolation method, Lagrange interpolation method and the like can be used. Approximation Select at least one point from the approximated area and use it more than the number of approximated areas. For example, it is possible to select both ends of a plurality of continuous regions and contact points of each region. Further, the midpoint of each region can also be used for approximation.

[0086] In a cross section perpendicular to the X-axis direction and parallel to the Y-axis direction, an angle with respect to the front direction

The ratio of the light emitted within 30 degrees is 50% or more, and the ratio of the light emitted within 30 degrees with respect to the front direction in the cross section parallel to the X axis direction and perpendicular to the Y axis direction is When it is 50% or more, a surface light source element having high luminance in the front direction can be obtained. For display devices such as personal computer monitors that require high front brightness, this value is more desirable if it is 60% or more, and more desirably 80% or more. On the other hand, for a display device that requires a wide viewing angle, such as a lighting signboard, if the ratio of emission in the front direction is too high, light is directed only in the front direction and the viewing angle becomes narrow. Therefore, when used for lighting signs, etc., this value is preferably 60% to 80%.

[0087] The longer the distance H between the light emitting surface of the point light source and the first light control unit and the distance H between the light emitting surface of the point light source and the second light control unit, the longer the luminance uniformity and color uniformity. Desirable because of high nature

2

That's right. However, if the length is too long, the thickness of the entire apparatus increases, which is not preferable. The distance between the point light source and the light control member is preferably 5 to 50 mm. More desirably, it is 10 mm to 30 mm. In addition, the ratio of the period of the point light source, D / H, D / H is expected to be 0.5-3.

1 1 2 2

More preferably, it is! ~ 2.

[0088] Desirably, the width P of the ridge-shaped protrusions and the width P of the ridge-shaped protrusions are 10 111 and 500 111, respectively. 500〃 m

1 2

If it is larger, the pattern itself is visually recognized from the emission surface, and the appearance quality is lowered. On the other hand, if it is smaller than 1Οπι, it will be colored by the diffraction phenomenon and the appearance quality will be lowered. More preferably, it is 20 mm 111, 400 mm 111, and more preferably 40 mm force, 300 mm. Within this range, the visibility of the pattern itself is difficult to observe, and the production becomes easier and the productivity is improved. Further, in the image display device in which the transmission type display device is provided on the exit surface side of the surface light source element of the present invention, P and P are in the range of 1/100 to 1 / 1.5 of the pixel pitch of the transmission type display device.

1 2

I want it! / Larger than this! /, And interference fringes between the pixel pitch occur, and the appearance quality deteriorates.

Yes

[0089] The method for producing the light control member of the present invention is not particularly limited, but may be extrusion molding or injection molding. 2P (Photo Polymerization) molding using mold and UV curable resin. However, when providing convex parts, it is necessary to select an appropriate molding method in consideration of the size of the convex parts, the shape of the convex parts, mass productivity, and the like. If the main surface is large, extrusion molding is suitable!

[0090] In addition, the normal hook-shaped convex part 1 and the hook-shaped convex part 2 may each be provided with a flat portion between the force S and the hook-shaped convex part 1 and / or the hook-shaped convex part 2 that are continuously arranged. . By providing the flat portion, the convex portion of the mold becomes difficult to be deformed, which is advantageous in forming the convex portion. In addition, since the light directly above the point light source is emitted in the front direction, it is effective in improving only the luminance directly above the point light source. On the other hand, when the flat portion is not provided, the light beam direction can be controlled on the entire emission surface of the first light control unit and / or the second light control unit. It is easy to make the intensity distribution uniform.

[0091] Further, the cross-sectional shape in the X-axis direction of the hook-shaped convex part 1 in the first light control unit is the same shape, and the Y-axis direction of the hook-shaped convex part 2 in the second light control unit The cross-sectional shape is desirably the same shape. Because the optical properties of the light control member are uniform, exact alignment is not necessary, and it is possible to immediately respond to changes in the display size and the number and arrangement of point light sources, which improves productivity. A light source element can be manufactured.

As the material for the light control member, any optically transparent material can be used.

Examples thereof include methacrylic resin, polystyrene resin, polycarbonate resin, cycloolefin resin, methacryl styrene copolymer resin, and cycloolefin alkene copolymer resin.

In order to use more light, a reflector or the like may be used on the back surface of the light source. By using the reflector, the light emitted from the light source in the back direction and the light emitted from the light control member in the back direction can be directed to the front direction, so that more light can be used and high luminance can be obtained. Is possible.

The reflecting plate has a function of reflecting light emitted from the light source to the back side in the front direction. A reflectance of 95% or higher is desirable because of high light utilization efficiency. Examples of the material of the reflector include metal foils such as aluminum, silver, and stainless steel, white coating, and foamed PET resin. In order to increase the light utilization efficiency, it is desirable that the material has a high reflectance. This includes power S such as silver and foamed PET. In order to improve brightness uniformity, the material should be diffusely reflected. Good. This includes foamed PET.

[0095] Further, in order to further improve luminance uniformity and color uniformity, the light control member of the present invention may be provided with a light diffusion means. As the light diffusing means, a method of providing random irregularities such as embossing on the main surface of the light control member, a method of providing fine particles that diffuse a small amount of light inside the structure, and a diffusion sheet as the incident surface of the light control member And a method of providing them on the side and / or the exit surface side, or a combination thereof.

[0096] Random irregularities can be realized by applying a solution in which fine particles are dispersed to the main surface by spraying, molding by extruding a resin in which fine particles are dispersed, and transferring from a mold having irregularities. is there. As for the degree of unevenness, the arithmetic average roughness Ra is desirably 3 m or less. If it is larger than this, the front luminance is lowered because the diffusion effect becomes too large.

[0097] When fine particles for diffusing light are provided inside the structure, the concentration of the fine particles can be kept very low compared to a normal diffusion plate. Any light diffusing material used in a fine particle diffusion plate or the like can be suitably used. A suitable concentration of fine particles varies depending on the material. For example, 0.4% by weight of siloxane polymer particles is dispersed in a methyl styrene / methacrylate copolymer.

[0098] In the case where the light control member is arranged on the most light source side! /, N! /, The thickness of the light control member may be set in consideration of the strength, productivity, etc. of the light control member itself! /. When used as a normal surface light source element, the vicinity of the end surface is fixed together with the light control member arranged closest to the light source, so that even a thin sheet is unlikely to stagnate. Therefore, the light control member that is not closest to the light source can be made thinner than the light control member that is closest to the light source. The light control member that is not closest to the light source is preferably thinner in order to reduce the thickness of the entire apparatus. The force thickness varies depending on the size of the surface light source element. The thickness is preferably 0.05 mm to lmm. If it is thinner than this, the strength of the light control member itself is lowered, and the quality is lowered due to deformation or the like. If it is thicker than this, the surface light source element becomes thick and the weight also increases. Furthermore, in order to prevent deformation of the light control member due to heat, etc., and to obtain high productivity by extrusion molding, etc., 0.1 mm to 0.7 mm is more desirable, and 0.2 mm force, 0.5 mm is more desirable. desirable.

[0099] Further, a transparent support substrate made of resin, glass or the like is stacked on the light source side of the light control member. It may be provided. By disposing the support substrate, it is possible to support the light control member even if the light control member is made as thin as 0.1 mm to 1 mm, for example. By making the light control member thinner, molding by extrusion molding or the like becomes easier and productivity is improved. In addition, it becomes easier to support a light control member that becomes increasingly difficult as the surface light source element becomes larger. The thickness of the support substrate is not particularly limited, but is usually from 1 mm to 5 mm, and more preferably from 2 mm to 4 mm from the viewpoint of weight reduction and strength. The supporting substrate may be improved in diffusibility by dispersing fine particles for diffusing light therein, embossing on the surface, or applying fine particles. In the case of dispersing fine particles inside or embossing on the surface, a suitable material that is preferable in production that the base material is a thermoplastic resin is equivalent to the light control member. In addition, the support substrate may be bonded to the light control member, for example, it can be bonded with a transparent adhesive or the like, thereby simplifying the process of assembling the surface light source elements and further shifting the light control member. And generation of wrinkles can be prevented.

[0100] There is no problem even if the support substrate is made of several kinds of plates having different refractive indexes, for example, when the support substrate is used and when the support substrate and the light control member are joined. In this case, a can be obtained by deriving an equation corresponding to equation (8), in accordance with the idea presented so far.

li

is there. However, when the refractive index variation is within 90%, the refractive indices n and n are

Equation (8) can be derived by approximating according to the thickness ratio. For example, if the part of the support substrate consists of three plates with refractive indices n ', n' ', n' '' and plate thicknesses T ', Τ' ', Τ' '', η is (η 'Τ' + η "· Τ" + η "'· Τ"') / Τ

12 1 1 1 1

[0101] When fine particles that diffuse light having different refractive indexes are dispersed, the amount of the fine particles used is small in the present invention, and thus the influence of the refractive index need not be considered.

[0102] Further, a diffusion sheet may be used in order to obtain more uniform brightness and color uniformity, and a prism sheet, a deflection separation film, or the like may be used in order to obtain high frontal brightness.

[0103] The light control member of the present invention can also be used for light sources other than a plurality of point light sources. For example, uniform and high brightness can be obtained in a wider range by using a single point light source. In addition, the light control unit included in the light control member of the present invention includes a plurality of linear light sources arranged in a virtual plane parallel to the X plane and parallel to the X axis direction and along the vertical axis, or the axial direction Linear light sources arranged along the X axis parallel to the X axis It is possible to control the direction of light rays from the light source, and high luminance uniformity can be realized. As these linear light sources, it is also possible to use a linear light source configured by linearly arranging fluorescent light sources or point light sources such as LEDs at narrow intervals.

[0104] Further, the image display device of the present invention is realized by providing a transmissive display device on a surface light source element, and a transmissive liquid crystal panel or the like is raised as the display device. As a result, it is possible to obtain an image display device that has high luminance uniformity and color uniformity with high luminance on the display surface and good color reproducibility.

Example

[0105] Examples of the present invention will be described below, but the present invention is not limited thereto.

The configuration of the surface light source element of this example is as shown in the schematic diagram of FIG.

In order to obtain a plurality of point light sources of the present invention, as shown in FIG. 4, red, blue, and green chip-type LEDs are used as examples;! To 3, D = 10 mm D = 25 mm, examples 4 = 6 D = 10mm D

1 2 1 2

= 33 mm, in Example 79, D = 20 mm, D = 25 mm, and arranged periodically. here

1 2

The period is the distance from the position where the red LED is placed in the X-axis direction to the position where the red LED is placed, and D is the place where the red LED is placed in the Y-axis direction.

2

This is the distance from the position to where the red LED is located.

[0107] In carrying out the present invention, the light control member is disposed in the order of the first light control member and the second light control member in the front direction at a position 20 mm from the light emitting surface of the light source in the front direction. The The distance H from the light emitting surface of the light source to the incident surface of the first light control unit is 20 mm, and the distance H from the light emitting surface of the light source to the incident surface of the second light control unit is 23 mm. Also, the light source

2

A 95% reflective plate made of foamed PET resin is installed on the back side.

As the light control member of the present invention, a light control member 1 1 6 having a first light control unit, a light control member 2— ;! 2-7 having a second light control unit, and Produced by the method

[0109] In order to obtain the ridge-shaped convex portion 1 in the light control member of the present invention, an ultraviolet curable resin (refractive index 1.) was obtained from a mold in which groove-shaped concave portions having a width of 60 in were continuously formed by cutting. 55) A 2 mm thick polystyrene resin (refractive index 1.60) substrate is formed with a ridge-shaped convex part. 1 light control unit is produced. Similarly, in order to obtain the ridge-shaped convex part 2, from a mold in which groove-shaped concave parts having a width of 60 11 m are continuously formed in parallel by cutting, the thickness is increased with an ultraviolet curable resin (refractive index 1.55). the ridge-shaped protrusions formed 0. 5 mm of styrene-butadiene rubbery copolymer of about 10 weight ^_0/0 methyl methacrylate is dispersed-styrene copolymer resin (refractive index 1.54) substrate, the second A light control unit is produced.

[0110] The shape of the groove-shaped concave portion of the mold in the bowl-shaped convex portion 1 is N = 50, and the inclination Φ determined by f (X), X, and X shown in Table 1 and the width a in the X-axis direction a Each region with N ~ N min max li li 1 1

Similarly, they are prepared in the order of the regions shown in Table 1. Similarly, the shape of the groove-shaped concave portion of the mold in the ridge-shaped convex portion 2 is N = 50, and f (Y), Y, Υ shown in Table 1

mm max

Each region N to N with a defined slope Φ and width a in the radial direction is defined as the region shown in Table 1.

2j 2j 2 2

Prepare according to the order.

[0111] Regarding the light control members 1 2 to 16 and the light control members 2 2 to 2-7 in Examples 2 to 9, in the hook-shaped protrusions 1 and the hook-shaped protrusions 2, The entire region is approximated to a curve by the least square method. The points used for approximation are the two points on both ends of the convex part and all the contacts (2N or 2N points) in each region.

1 2

[0112] Regarding the implemented configuration, the intensity distribution of the emitted light in the front direction is evaluated by measuring the distribution of the front luminance. The front brightness is measured by using a luminance meter (Topcon Co., Ltd., BM-7) with a measurement angle range of 0.2 degrees, moving the measurement distance constant, and moving by lmm along the X axis where the point light sources are arranged. Measure for one cycle. Also, measure for one cycle while moving by lmm in the Y-axis direction. Luminance uniformity in the X-axis direction is the ratio of L (X), which is the minimum value of luminance in one cycle measured in the X-axis direction, to L (X), which is the maximum value.

1 mm 1 max 丄 mm

Calculated as L (X). Similarly, the brightness uniformity in the Y-axis direction

1 max

The ratio of L (Y), which is the minimum value of luminance in one cycle, to L (Y), which is the maximum value,

2 min 2 max 2

Calculate as (Y) / L (Y). The closer the value of L (X) / L (X) is to 1, the more the X axis is mm 2 max 1 mm 1 max

Uniform brightness uniformity The closer the L (Y) / L (Y) value is to 1, the more the brightness in the radial direction

2 min 2 max

Therefore, these values serve as indicators of the luminance uniformity of the surface light source element.

[0113] The ratio of the light emitted in the front direction is determined by measuring the luminance distribution for each angle, converting the obtained luminance into energy, Calculate the percentage of total energy. The luminance distribution for each angle is obtained by measuring the same luminance with a luminance meter (BM-9 manufactured by Topcon Co., Ltd.) attached to the rotating table, with a measurement angle range of 0.2 degrees, and a constant measurement distance. taking measurement.

Next, a transmissive liquid crystal panel is arranged in the front direction of the exit surface of the surface light source element of this embodiment, and the screen quality and the brightness of the screen are observed.

[0115] The configurations and evaluation results of Examples and Comparative Examples are shown in FIG.

[0116] By using the light control member having the hook-like convex part 1 and the hook-like convex part 2 from Example 1, the image of the point light source is reduced on the emission surface, and the luminance in the front direction is reduced. The uniformity of color and the uniformity of color are improved. Furthermore, since the ratio of light emitted in the front direction where the light use efficiency is high is increased, the luminance in the front direction is high.

Next, when a transmissive liquid crystal panel is arranged in the front direction of the exit surface of the surface light source element of Example 1, the use of a plurality of point light sources improves the color reproducibility and further improves the brightness and color. Highly uniform, good screen quality! /, Brightness! /, Images can be obtained.

[0117] From Examples 2 to 9, in the hook-like convex portion 1 and / or the hook-like convex portion 2, a smooth angular distribution can be obtained by approximating the entire area of each convex portion with a curve. In addition, since the joints in each area of the convex part have a smooth shape, breakage is caused << because the change in the light emission direction due to the breakage of the joint part in each area and unnecessary scattering are difficult to occur. In addition, brightness and color uniformity are high, and front brightness is high.

[0118] As Comparative Example 1, an evaluation was performed in the case of using a normal fine particle-containing diffusion plate.

The diffusion plate was produced by extruding a methyl methacrylate-styrene copolymer resin in which 1.9% by weight of cyclohexane-based polymer particles were dispersed as fine particles for diffusing light. Evaluation was carried out when a diffusion sheet was arranged in the front direction of the diffusion plate containing fine particles. In this case, the luminance uniformity is low because the light source image is not sufficiently reduced. Further, since the light utilization efficiency is low, high front luminance is not obtained. In addition, when a transmissive liquid crystal panel is placed in the front direction of the emission surface of the surface light source element and observed, the light source image is remarkably observed and the screen quality is poor. In addition, the screen is dark because there is little light going to the front.

[0119] As Comparative Example 2, hook-shaped convex part 1 and hook-shaped convex part 2 are hook-shaped prisms having an apex angle of 90 degrees. Was evaluated on the light exit side of the light control member. When the emission surface of the surface light source element is observed from the front, the luminance is greatly reduced in the portion directly above the light source, and the luminance uniformity is poor. In addition, the brightness is uniform for different color light sources! Further, when a transmissive liquid crystal panel is placed in front of the exit surface of the surface light source element and observed, the image quality is poor because the light source image is not reduced.

[0120] Figs. 12 and 13 show the principle of light control performed by the prism having a vertex angle of 90 degrees, which is mentioned as Comparative Example 2. As shown in FIG. 12, since all the light 7 incident on the prism 10 from the front direction is totally reflected and returns to the light source side, the amount of transmitted light at the position of the light source is zero. On the other hand, as shown in FIG. 13, since the light 7 incident on the prism 10 from an oblique direction is refracted by the prism and deflected near the front direction, the amount of transmitted light is large. Therefore, the brightness uniformity cannot be obtained with the prism mentioned as Comparative Example 2.

[0121] As Comparative Examples 3 to 5, as at least two light control members, light control members 17 and 18 having a first light control unit and light control member 2 having a second light control unit 2- Evaluations were performed using 8-2-10. For light control members 1—7 and 1 8 _§ (X) / g (X) is 0.8

When viewed from the front direction because it is smaller than 1 mm 1 max, the luminance is high directly above the light source in the X-axis direction, and the luminance uniformity is poor. For light control members 2-8 to 2-10, g (Y) / g (Y)

When the frontal force is observed because 2 mm 2 max is smaller than 0.8, the luminance is high and the luminance uniformity is poor just above the light source in the Y-axis direction. Furthermore, the luminance is not uniform for the light sources of different colors, and the color is emphasized at the location of the light source of each color, and the color uniformity is poor. In addition, when a transmissive liquid crystal panel is placed in the front direction of the exit surface of this surface light source element, the luminance and color uniformity are low, so the screen quality is poor!

[0122] As Comparative Example 6, a lenticular lens made up of a part of an arc whose cross-sectional shape is expressed by the formula (31) as the ridge-shaped convex portion 1 and the ridge-shaped convex portion 2 is disposed on the light exit surface side of the light control member. An evaluation was conducted when the wrench sheet 1 was used. In this case, since the direction of the light emitted from the light control member and the amount of light are not controlled, the luminance and color uniformity are not sufficient to reduce the light source image sufficiently. Further, when a transmissive liquid crystal panel is placed in front of the exit surface of the surface light source element and observed, the light source image is recognized remarkably, and the screen quality is poor due to low luminance and color uniformity.

z: Coordinates in the height direction of the cross-sectional shape of hook-shaped convex part 1 or hook-shaped convex part 2 when the top is the origin

P: Position coordinate in the X-axis direction or Y-axis direction of the cross-sectional shape of bowl-shaped convex part 1 or bowl-shaped convex part 2 when the top is the origin

As Comparative Example 7, a lens in which a lenticular lens composed of a part of a parabola, the cross-sectional shape of which is represented by the expression (32), as the bowl-shaped convex part 1 and the bowl-shaped convex part 2 is arranged on the light exit surface side of the light control member Evaluation was performed when Sheet 2 was used. In this case, since the direction of the light emitted from the light control member and the amount of light are not controlled, the luminance and color uniformity are not sufficient to reduce the light source image sufficiently. Further, when a transmissive liquid crystal panel is placed in front of the exit surface of the surface light source element and observed, the light source image is recognized remarkably, and the luminance and color uniformity are low, resulting in poor screen quality.

ζ: Coordinates in the height direction of the cross-sectional shape of hook-like convex part 1 or hook-like convex part 2 when the vertex is the origin

Ρ: Position coordinate in the X-axis direction or Υ-axis direction of the cross-sectional shape of the ridge-shaped convex part 1 or ridge-shaped convex part 2 when the top is the origin

Claims

The scope of the claims

One of the normals of the X—Y plane parallel to the X axis and the Y axis perpendicular to the X axis as the front direction, at least an emission surface parallel to the X—Υ plane, a plurality of point light sources, 2 Sheet-shaped light control member,

The plurality of point light sources are periodically arranged in the X-axis and Υ-axis directions in a virtual plane parallel to the X-Υ plane, and include a light emitting surface parallel to the X-Υ plane,

The light control member is disposed parallel to the X-— plane and in front of the plurality of point light sources;

The exit surface is a surface light source element disposed on the front direction side of the light control member,

Of the two light control members, a first light control unit including a plurality of hook-shaped protrusions 1 orthogonal to the X-axis direction and parallel to the X-axis direction is provided on one emission surface side,

And,

Of the two light control members, a second light control unit comprising a plurality of ridge-shaped convex portions 2 parallel to the X-axis direction and perpendicular to the Υ-axis direction is provided on the other emission surface side. And

The center position of the point light sources arbitrarily selected, where D is the length of one cycle along the X axis and D is the length of one cycle along the Υ axis of the plurality of point light sources. The origin, X-axis direction

2

The position coordinate of X is X and the position coordinate in the Υ axis direction is Υ.

In a plane parallel to the X-axis direction and perpendicular to the X-axis direction!

The distance between the light emitting surface of the selected point light source and the first light control unit is set, and the light incident on the first light control unit from the selected point light source is output on the exit surface at X. Let f (X) be a function that expresses the intensity of light emitted in the front direction.

g (X) = f (X-D) + f (X) + f (X + D)

And

Di / Z

1 1 mm 1 max 1 mm 1 max is 0.8 or more,

The minimum value of X is — 3. OD≤X 0.5. The maximum value of X is in the range of 0.5D ≤X ≤3.0D

max 1 max 1

, The coordinates of both ends to become 0)

δ = (X -X) / (2N +1)

1 max mm 1

X = iX δ

a = tan ^_1 (X / H)

li i 1

β = sin ((1 / n) sin)

li 1 i

γ = sin (1 / n) sin)

li Is i

a ccf (X + T -tan y) -cosO ^e cos β / \ (a) / cos (a) / cos (0 ― β li 1 i 1 li li li 1 li li li li

)

Φ = tan ^_1 ((n -sin / 3) / (n 'cos / 3 —1))

li 1 li 1 li

(However, N _i: Natural number

i: -N force, etc. Integer of N

n _i : Refractive index of hook-shaped convex part 1 of the first light control part

n: Refractive index of the base material of the first light control unit

Is

a: The width of area i in the X-axis direction

li

Φ: Slope inclination with respect to the exit surface of region i

li

I (α): arbitrarily selected point light source unit along the X-axis in the direction of α

1 li li

Intensity of light emitted per angle)

And,

2

A function that expresses the intensity of light incident on the second light control unit from the selected point light source to the front direction of the exit surface at the position coordinate Y in the Y-axis direction is represented by f (Y),

2

g (Y) = f (Y-D) + f (Y) + f (Y + D)

2 2 2 2 2 2 In a range,

The ratio of g (Y) that is the minimum value of g (Y) to g (Y) that is the maximum value, g (Y) / g (Y) is 0.8 or more,

The minimum value of Y is Y 3. OD ≤ Y ≤-0.

The maximum direct value of Y is in the range 0.5D ≤Y ≤3.0D

(Y and Υ are the coordinates of both ends where the value of f (Υ) is attenuated around the arbitrarily selected point light source with Υ = 0 and becomes substantially 0),

A surface light source element _{c in which} the cross-sectional shape in the Y-axis direction of an arbitrary ridge-shaped convex part 2 is (2N + 1) differently inclined regions N to N forces represented by the following formula:

6 = (Y)) / (2 Ν +1)

γ shout x δ

a = tan ^_1 (Y / H)

β = sin ((1 / n) sin)

γ = sin (1 / n) sin)

a ccf (Y + T -tany) -cosO -cos β cos (a) / cos (Φ ― β

)

Φ = tan— ((n -sin / 3) / (n 'cos / 3 1))

(Where N is a natural number

j: integer from -N to N

n: Refractive index of the base material of the second light control unit

a: Width of area j in the Y-axis direction

Φ: slope of the slope with respect to the exit surface of region j

I (a): The intensity of light that passes through the first light control unit from an arbitrarily selected point light source and radiates per unit angle in the direction of α along the Y-axis direction)

[2] The surface light source element according to claim 1, Regions Ni representing the cross-sectional shape in the X-axis direction of the hook-shaped convex portion 1 are arranged in the order of the position coordinates of the X-axis,

And,

twenty two

A surface light source element characterized by being arranged in order! /.

[3] The surface light source element according to claim 1 or 2,

The cross-sectional shape in the X-axis direction of the ridge-shaped convex portion 1 approximates the shape of at least one pair of two adjacent regions among the (2N + 1) differently inclined regions forming the convex portion by a curve. Shape

And,

The cross-sectional shape in the Y-axis direction of the hook-shaped convex portion 2 has (2N + 1) inclinations forming the convex portion.

2

A surface light source element having a shape obtained by approximating the shape of at least one pair of two adjacent regions of different regions by a curve.

[4] Claim: A surface light source element according to any one of! To 3,

In the cross section parallel to the X-axis direction and perpendicular to the Y-axis direction in the first light control unit, the proportion of light emitted within an angle of 30 degrees with respect to the front direction is 50% or more of the total emitted light. And

And,

In the cross section perpendicular to the X-axis direction and parallel to the Y-axis direction in the second light control unit, the proportion of light emitted within an angle of 30 degrees with respect to the front direction is 50% or more of the total emitted light A surface light source element.

[5] A sheet-like light control member having light control means for controlling a light beam direction along the X-axis or the Y-axis, which is provided in the surface light source element according to any one of Claims! To 4.

[6] An image display device comprising: a transmissive display device disposed in the front direction of the surface light source element according to any one of [1] to [4].