JP2003217824A - Organic light emitting element, light emitting element array using the organic light emitting element, projector, optical write device, display element and electrophotographic printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic light emitting element, capable of attaining high integration at a low cost, and controlling the efficiency of taking light emitted from a light emitting layer to the outside and light emission characteristics. <P>SOLUTION: In this organic light emitting element, at least one or more light emitting parts formed by stacking an organic layer containing a light emitting layer formed of organic light emitting material between a pair of electrodes 2, 4 are provided on a base plate 1, the base plate 1 is provided with a tapered light passing hole 5 in a position corresponding to the light emitting part 6. Light emitted from the light emitting layer is emitted through the light passing hole 5 from a second face 1b side on the opposite side to the first face 1a of the base plate to the outside. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated organic light emitting device having an organic layer including a light emitting layer made of an organic light emitting material between electrodes. In particular, the present invention relates to a structure of an organic light emitting device that improves a light emission state. Further, the present invention relates to a display element, a light emitting element array, and a floodlight using the organic light emitting element. Further, the present invention relates to an optical writing device using the light emitting element array for an electrophotographic process and the like, and an electrophotographic printer using the organic light emitting element, the light emitting element array, the optical writing device, and the display device.

[0002]

2. Description of the Related Art Recently, Tang et al. (Appl. Phy
s. Lett. 51 (1987) p913) produced an organic light emitting device (organic electroluminescence device) by stacking two organic thin films between two electrodes by a vacuum evaporation method, and realized high brightness with a low driving voltage. With this as a starting point, research on stacked organic light emitting devices has been actively conducted.

For example, as shown in FIG. 9, a general structure of an organic light emitting device for emitting dot matrix light is that a transparent ITO film is formed on one surface of a glass substrate 111, and the ITO film is formed into a stripe shape. Is etched to form a transparent electrode 112, a hole transport material layer such as a triphenylamine derivative (TPD) is provided on the surface thereof, and an electron transport material layer such as an aluminum chelate complex (Alq ₃ ) which is a light emitting material is provided thereon. The organic layer 113 is formed by stacking a light emitting layer that also serves as the above, and then a back electrode 114 of Al, Li, Ag, Mg, In or the like is vacuum-deposited in a stripe shape in a direction orthogonal to the pattern of the transparent electrode 112. It is a structure formed by the above. A predetermined current is applied to the intersection of the transparent electrode 112 and the back electrode 114 to cause the light emitting layer to emit light, and the light is emitted to the glass substrate 111 side.

The organic light emitting device has such a simple device structure and has a possibility of cost reduction, and is expected as a large area display or a line light source for an electrophotographic copying machine which requires a long length. And other self-luminous display (O. Hosokawa, et. Al., SID 98
DIGEST, p7) and an image forming apparatus such as an electrophotographic copying machine using a light emitting element array (Japanese Patent Laid-Open No. 11-196).
Application development such as Japanese Patent No. 248) is active.

It is important to increase the light emission brightness of the organic light emitting device when the product is commercialized, and it is necessary to add the electron transport layer to the above-mentioned two-layer laminated structure to separate the functions of carrier transport and light emission so that holes and electrons are separated. (Or exciton) is effectively confined and a three-layer structure (Jpn. J. App
l. Phys. 27 (1988) L269. L713)
Have been proposed.

Apart from the research and development of organic materials having high luminous efficiency, optimization of the light emitting mechanism of the organic light emitting element has also been studied. Light emitted by the organic light emitting element has no directivity and is reflected and absorbed at the interface between the glass substrate and layers that form the element, so it is difficult to effectively extract light. N.
Takada et al. (Appl. Phys. Lett. 6).
3, p2032.1993) proposes to improve the light extraction efficiency and increase the emission brightness by a resonator structure. According to this, by using a resonator (microcavity) in which an Ag anode, an organic light emitting layer, and a cathode are stacked on a glass substrate, it becomes possible to give directivity to light emission, and to effectively emit light from the light emitting layer. It can be taken out to the transparent substrate side.

By changing the structure of the substrate in this manner, a high-brightness organic light emitting device can be formed, and the feasibility of the product is further increasing.

[0008]

However, considering the application of the organic light emitting device to a display device such as a display and a line light source of an electrophotographic printer, a light emitting device using the current organic light emitting device is considered. Since the array has a large unit light emitting element (pixel) size, the number of elements per unit length is smaller than that of a liquid crystal display, a compound semiconductor LED array, etc., and the degree of integration is low. Further, if the degree of integration is increased, the size per element is reduced, and the light emitting area is reduced, so that the light emission luminance is reduced. Therefore, it cannot be said that the number of devices (or integration degree) per unit length is still sufficient, and even if the integration degree is increased, a proposal of an element structure for efficiently extracting light emitted from the organic light emitting layer to the outside Is desired.

In Japanese Unexamined Patent Publication No. 7-37688, an organic light emitting element is provided on a substrate having a high refractive index portion formed in a columnar shape in the thickness direction of the substrate and having a refractive index larger than that of the surroundings, and emitted light of each pixel is crossed. We propose a technology to reduce talk and improve light extraction efficiency to achieve high brightness.
According to this method, it is considered possible to reduce the columnar dimension of the high refractive index portion depending on the pixel, regardless of the substrate thickness.

However, when the device is highly integrated, the following problems can be considered.

First, when a substrate having a large number of columnar structures having different refractive indexes formed in the thickness direction of the substrate is to be formed from fibers, it is necessary to process the bundled fibers into a substrate shape, and further in the case of high integration. It is necessary to use a fiber having a diameter smaller than that of a ready-made fiber, which increases the substrate cost.

Further, not all the light is reflected at the boundary between the high refractive index portion and the low refractive index portion, and it is necessary to provide another member for absorbing the leaked light that is not reflected at the boundary portion, so that the degree of integration of the device is improved. This hinders the cost and increases costs.

Further, when a columnar structure having a different refractive index is formed on a substrate by an ion exchange method utilizing diffusion, ions are isotropically diffused into the substrate. Therefore, if adjacent light emitting elements are brought close to or less than the substrate thickness. The high refractive index portion of the light emitting element cannot be separated for each element. Therefore, the substrate needs to have a thickness equal to or larger than the element pitch. In the ion exchange method,
Since the ion-exchanged part expands, the substrate warps. If the integration of light-emitting elements is increased and the substrate is made thinner, the organic light-emitting element warps greatly with the substrate due to the film stress of each layer of the electrode and the organic light-emitting layer in the laminated type element, and it cannot be used as a line light source for displays or copying machines. Alternatively, the stress may cause mechanical damage during the manufacturing of the element.

The present invention was conceived in view of the above problems, and an object thereof is to achieve high integration at a low cost, and further to take out the light emitted from the light emitting layer to the outside. It is an object of the present invention to provide an organic light emitting device that can also control the light emission characteristics.

Furthermore, the present invention provides a light emitting device array comprising the above organic light emitting device, provides a projector and a display device comprising the above organic light emitting device or the above light emitting device array, and above the light emitting device array. It is an object of the present invention to provide an optical writing device provided with.

It is another object of the present invention to provide an electrophotographic printer equipped with at least one of the organic light emitting device, the light emitting device array, the projector, the display device and the optical writing device. It is what

[0017]

A first invention for solving the above problems includes a transparent first electrode and a light emitting layer made of an organic light emitting material on a first surface which is one surface of a substrate. The substrate has at least one light emitting portion formed by stacking an organic layer and a second electrode, and a light passage hole having a taper is formed in the substrate at a position corresponding to the light emitting portion. The organic light emitting element is characterized in that light emitted from the substrate is emitted to the outside from the second surface side, which is the surface opposite to the first surface of the substrate, through the light passage hole.

In the first aspect of the present invention, "the light passage hole is formed so that the diameter of the second surface side is larger than the diameter of the first surface side". "The light passage hole is formed so that the diameter of the first surface side is larger than the diameter of the second surface side", "A light-reflecting mirror layer on the side wall of the light passage hole" Is formed "," the area of the end portion of the light passage hole on the first surface side is
Larger than the area of the light emitting portion "," providing an optical resonator structure on the first surface side of the light passage hole ",
"An optical resonator structure is provided on the second surface side of the light passage hole", "An optical lens is provided on the second surface side of the light passage hole", "The optical lens is a spherical surface" “Being a lens” and “the optical lens is a cylindrical lens” are included as preferable embodiments.

A second invention for solving the above-mentioned problems is as follows.
A light emitting device array comprising the organic light emitting device of the first invention.

A third invention for solving the above-mentioned problems is as follows.
A projector comprising the organic light-emitting device according to the first aspect of the invention.

The present invention also includes a floodlight in the above-mentioned third invention, which is characterized by including the light-emitting element array of the above-mentioned second invention.

A fourth invention for solving the above problems is as follows.
A display device comprising the organic light emitting device of the first invention.

The present invention also includes a display device according to the fourth invention, which is characterized by including the light emitting device array of the second invention.

A fifth invention for solving the above problems is as follows.
An optical writing device comprising the light emitting element array of the second invention.

A sixth invention for solving the above problems is as follows.
An electrophotographic printer comprising the organic light emitting device of the first invention.

The present invention according to the sixth invention, "provided with the light emitting element array according to the second invention".
It also includes an electrophotographic printer characterized by "having the display element of the fourth invention" and "having the optical writing device of the fifth invention".

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The organic light emitting device of the present invention comprises a transparent first electrode on one side of a substrate, an organic layer including a light emitting layer made of an organic light emitting material, and a second electrode. And at least one light emitting portion formed by laminating the light emitting portion, and a light passage hole having a taper at a position corresponding to the light emitting portion is formed in the substrate, and the light emitted from the light emitting layer is It is characterized in that the light is emitted to the outside from the second surface side, which is the surface opposite to the first surface of the substrate, through the light passage hole.

In the organic light emitting device having the above structure,
Light generated from the light emitting layer by applying a voltage equal to or higher than a predetermined threshold value to the organic layer arranged between the two electrodes passes through the light passage hole of the substrate and is emitted to the outside from the second surface side of the substrate. To do. At this time, a part of the emitted light is reflected by the side wall of the tapered light passage hole (hereinafter, abbreviated as a tapered portion), the spread angle of the emitted light is suppressed, and the light traveling in the horizontal direction of the substrate is reduced. With such a function, it is possible to efficiently take out light emission, and it is possible to obtain the effect of improving the luminance in the substrate vertical direction. In addition, a part of the light generated from the light emitting layer is reflected at the tapered portion, and the reflected light and the light emitted directly from the light emitting portion without being reflected at the tapered portion intersect again, the light amount, the output, and the intensity. It is also possible to enhance the light emission characteristics such as.

In the present invention, the term "on the first surface," which is one surface of the substrate, includes not only the meaning of "on the substrate directly" but also the meaning of "on the portion where the light passage hole is provided".

By setting the taper angle of the light passage hole to an appropriate angle according to the design, the light reflection state changes,
The spread angle of the emitted light and the light traveling in the horizontal direction of the substrate can be adjusted. As a result, it becomes possible to control the extraction efficiency of the light emitted from the substrate. Furthermore, by setting this taper angle, the distribution of the light that reaches the tapered portion and is reflected, and the light that is directly emitted without reaching the tapered portion, is adjusted among the light emitted from the light emitting layer, depending on the directivity angle of light emission. can do. At this time, at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion, the light amount, output, and intensity thereof become high.
And the position where the directly emitted light and the reflected light intersect is
It can be adjusted by the taper angle. Therefore, by setting the taper angle appropriately and adjusting the degree of intersection between the light emitted directly and the light reflected by the taper portion, the desired distance from the substrate and
It is possible to control the light emission characteristics such as the amount of light, the output, and the intensity in the area.

Further, by setting the thickness of the substrate to an appropriate thickness in accordance with the design, it becomes possible to adjust the amount of light reflected by the tapered portion and control the spread angle of the light emission. Further, by setting the thickness of the substrate, it is possible to adjust the distribution of the light that reaches the tapered portion and is reflected, and the light that is directly emitted without reaching the tapered portion, among the light generated from the light emitting layer. . At this time, at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion, the light amount, output, and intensity thereof become high. Therefore, it is possible to control the desired distance from the substrate and the light emission characteristics such as the amount of light, the output, and the intensity in the area by adjusting the degree of intersection between the light emitted directly and the light reflected by the tapered portion. Become.

Further, by setting the processing depth of the light passage hole provided in the substrate to an appropriate depth according to the design, the light generated from the light emitting layer reaches the taper portion due to the directional angle of light emission. Thus, the distribution of the light that causes reflection and the light that does not pass through the tapered light passage hole and proceeds in the horizontal direction of the substrate and is not emitted in the vertical direction of the substrate can be adjusted. As a result, it is possible to control the extraction efficiency of the light emitted from the substrate. Furthermore, by setting this processing depth, in the light generated from the light emitting layer, the light that reaches the taper portion and causes reflection due to the directional angle of the light emission, and the substrate horizontal without passing through the hole having the taper portion. It is possible to adjust the distribution of the light that travels in the direction and is not emitted in the substrate vertical direction and the light that is emitted directly without reaching the tapered portion. At this time, at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion, the light amount, output, and intensity thereof become high. Therefore, since the amount of light reflected by the tapered portion can be adjusted by this, it is possible to control the light emission characteristics such as the amount of light, the output, and the intensity at the position where the directly emitted light and the reflected and emitted light intersect. Becomes

Further, by setting the diameter of the light passage hole provided on the substrate to an appropriate diameter according to the design, the light generated from the light emitting layer reaches the taper portion and is reflected by the directivity angle of the light emission. It is possible to adjust the distribution of the light that causes the light, the light that does not pass through the hole having the taper, travels in the horizontal direction of the substrate and is not emitted in the vertical direction of the substrate, and the light that directly emits without reaching the tapered portion. At this time, at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion, the amount of light, the output, and the intensity are high. Therefore, since the amount of light reflected by the tapered portion can be adjusted by this, it is possible to control the light emission characteristics such as the amount of light, the output, and the intensity at the position where the directly emitted light and the reflected and emitted light intersect. Becomes

If the light passage hole is formed so that the diameter on the second surface side is larger than the diameter on the first surface side, the light from the light emitting layer generated in the direction oblique to the light extraction direction of the substrate. Can be guided in the vertical direction of the substrate by the reflection of the taper portion, and when combined with light traveling in the light extraction direction of a part of the substrate, the light generated from the light emitting layer can be efficiently extracted, The brightness in the vertical direction of the substrate is improved.

If the light passage hole is formed so that the diameter on the first surface side is larger than the diameter on the second surface side, the luminous flux from the light emitting layer generated in various directions can be generated on the second surface of the substrate. The light generated from the light emitting layer can be efficiently extracted by focusing the light on the opening of the light passage hole on the side, and the brightness in the vertical direction of the substrate is improved.

Preferably, a light-reflecting mirror layer is formed on the side wall of the light passage hole. According to such a configuration, the reflectance at the tapered portion is improved, the extraction efficiency of the emitted light can be further improved, and the light directly emitted and the light reflected and emitted at the tapered portion are It is possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at the intersecting position.

Further, the area of the end portion of the light passage hole on the first surface side is preferably larger than the area of the light emitting portion.
With this structure, the light emitted from the light emitting layer is efficiently guided to the light passage hole, and the luminance in the vertical direction of the substrate can be improved without reducing the original light emission output. . The area of the end portion of the light passage hole on the first surface side is the opening area on the first surface side when the light passage hole penetrates the substrate, and the area of the light passage hole on the first surface side is When not penetrating, it is the area of the bottom of the light passage hole.

Further, it is preferable to provide an optical resonator structure on the first surface side or the second surface side of the light passage hole. By providing the emitted light with directivity by providing such an optical resonator structure, the light emission extraction efficiency and the light emission reflected at the tapered portion and the light emitted directly without being reflected at the tapered portion intersect each other. It is possible to improve the light emission characteristics such as the amount of light, the output and the intensity.

Further, it is preferable to provide an optical lens on the second surface side of the light passage hole.
Examples of the optical lens include a lens that collects, collimates, or diverges the light generated from the light emitting layer. By providing such an optical lens, the light emission extraction efficiency in the vertical direction of the substrate and the light emission reflected by the tapered portion,
It is possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at the intersecting position of the light emitted directly without being reflected by the tapered portion.

The above-mentioned optical lens is preferably a spherical lens. The spherical lens can be easily formed by the method described later, and the design of the degree of light emission convergence, collimation, and divergence is also easy.

In addition, it is preferable that the optical lens is a cylindrical lens. This allows the components of light in one direction to be converged. For example, when a plurality of organic light emitting elements are linearly arranged and used as a light source of an electrophotographic printer, it is possible to collect a light emitting component in a direction orthogonal to the arrangement direction of the organic light emitting elements. , Which is useful for sharpening the formed image.

Preferred embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

(Embodiment 1) Here, in addition to the description of this embodiment, a more specific description of the organic light emitting device of the present invention will be given.

FIG. 1 is a schematic view showing a first embodiment of the organic light emitting device of the present invention. (A) is a sectional view.
(B) is a plan view of the second surface side.

In FIG. 1, reference numeral 1 is a substrate, and 1a is a surface on both sides of the substrate 1 on which electrodes and organic layers are laminated.
A surface 1b is a second surface which is a surface opposite to the first surface of the substrate 1, 2 is a transparent first electrode, 3 is an organic layer including a light emitting layer made of an organic light emitting material, and 4 is a second electrode. 5 is a light passage hole, 6
Is a light emitting part.

In the organic light emitting device of this embodiment, the first electrode 2, the organic layer 3 and the second electrode 4 are laminated on the first surface 1a of the substrate 1, and the light emitting portions 6 are formed on the line at a constant pitch. ing. The first electrode 2 is a transparent electrode realized by, for example, ITO or ZnO: Al.

The organic layer 3 is composed of, for example, a triphenylamine derivative (TPD) and an aluminum chelate complex (Alq ₃ ) and is formed by continuously vacuum-depositing the first electrode 2 on the substrate 1. The second electrode 4 is, for example, Al, M
It is a metal electrode realized with gAg.

The first electrode 2 and the second electrode on the first surface of the substrate 1
Each of the electrodes 4 is formed in a strip shape, and the light emitting portion 6 is formed at the intersection thereof. The first electrode 2 is divided for each light emitting portion, and the current flowing through the light emitting portion 6 can be individually controlled. The second electrode 4 is formed commonly to all the light emitting units 6.

Then, a light passage hole 5 having a predetermined taper angle in the thickness direction of the substrate is provided at a position corresponding to the light emitting portion 6 of the substrate 1.
Is formed.

The substrate 1 may be a transparent substrate made of glass, resin, or the like, or may be a colored resin, glass, or a light-impermeable material such as silicon, metal, or ceramics. Note that the present invention can be preferably used as a color display element among display elements by taking advantage of the characteristics of the organic light emitting element. In this case, adjacent light emitting portions emit light of different colors. The configuration of is effective. In that case, it is more preferable that the substrate is impermeable to light.

Examples of the method of forming the light passage hole 5 in the substrate 1 include micromachining, fine processing such as laser ablation, and etching.

When the substrate is provided with the light passage hole 5 penetrating therethrough, first, the material forming the first electrode 2 is provided on the first surface 1a of the substrate by a method such as sputtering or CVD. After that, the first electrode 2 is formed by patterning by a method such as etching, and then the light passage hole 5 is provided from the side of the second surface of the substrate 1b by a method such as micromachining or laser ablation. It can be manufactured.

The light generated from the light emitting layer passes from the first electrode 2 through the light passage hole 5 of the substrate 1 and is emitted from the second surface 1b side. In FIG. 1, only five light emitting units are shown for convenience.

A voltage was applied between the first electrode 2 and the second electrode 4 of the organic light emitting device according to the present embodiment, and the light emission intensity of the light emitted from the light emitting layer on the second surface 1b side was measured. Then, as a comparison, the emission intensity of the organic light emitting device manufactured on a normal glass substrate having no light passage hole was measured. As a result, the organic light emitting device of the present invention had higher emission intensity than the organic light emitting device on the ordinary glass substrate.

Usually, the light emitted from the light emitting layer is emitted while spreading without directivity. In the present invention, the light emission is reflected by the tapered portion of the light passage hole 5 and is emitted to the second surface 1b side.
Therefore, as compared with the case where the organic light emitting element is formed using a normal glass substrate having no light passage hole, by the action of suppressing the spread angle of light emission and reducing the light traveling in the substrate horizontal direction, It has become possible to improve the light extraction efficiency in the direction perpendicular to the substrate 1.

When the organic light-emitting device is manufactured by changing the taper angle of the light passage hole 5, the reflection state of light in the taper portion changes, and the divergence angle of the emitted light emitted or the light propagates in the horizontal direction of the substrate. It was possible to adjust the amount of light not emitted in the vertical direction. As a result, it becomes possible to control the light emission extraction efficiency of the substrate 1 in the vertical direction.

Here, a method for controlling the light emission characteristics such as the light amount, output, and intensity of the organic light emitting element at a position separated by an arbitrary distance from the substrate will be described by exemplifying concrete numerical values.

FIG. 2 is a diagram for explaining a method of controlling the amount of emitted light, the output, and the intensity by utilizing the reflected light on the side wall of the tapered light transmitting hole. In FIG. 2, only one light emitting portion is shown for convenience. 2, the same reference numerals as those in FIG. 1 indicate the same parts. Reference numeral 7 denotes reflected light which is generated from the light emitting portion in a direction forming an angle α with respect to the normal to the substrate surface and is reflected at the tapered portion, and 8 is light emitted directly without being reflected by the side wall of the light passage hole 5. , Θ is the side wall taper angle of the light passage hole, D2 is the distance from the second surface side of the substrate where the direct emission light 8 and the reflected light 7 reflected by the side wall of the light passage hole 5 intersect, A is the substrate thickness, B Indicates the radius of the light passing hole on the first surface side.

At a position away from the substrate by a distance D2, the reflected light 7 generated from the light emitting layer and reflected by the side wall of the light passage hole 5
The light 8 emitted directly from the light emitting layer intersects, and therefore
The light amount, output, and intensity at this position can be increased as compared with the case of the direct emission light 8 alone.

This distance D2 is α, from the geometrical calculation.
It can be expressed as in Expression (1) using θ, A, and B.

[0061]

[Equation 1]

As can be seen from the equation (1), when the angle α changes, the distance D2 from the substrate surface where the reflected light 7 and the direct emitted light 8 intersect also changes. FIG. 3A shows, for example, the angle α and the distance D2 when the taper angle θ is 4 °, the substrate thickness A is 0.2 mm, and the radius B on the first surface side of the light passage hole is 0.02 mm. It is the result of calculating the relationship using the formula (1). As described above, the distance D2 from the substrate surface where the reflected light 7 and the directly emitted light 8 intersect differs depending on the angle α of the light emission incident on the light passage hole.

The intensity of light emitted from the light emitting layer changes depending on the directivity angle. Generally, the emission intensity decreases as the angle α in FIG. 2 increases. Therefore, based on the equation (1), the relationship between the emission intensity and the directivity angle in the emission from the light emitting layer is Lambertian.
When the relationship between the distance D2 from the substrate surface and the relative emission intensity is estimated assuming that the rules are followed, the result shown in FIG. 3B is obtained.

As described above, it is estimated that the relative light emission intensity is improved to about double with respect to the change of the distance D2, and the reflected light reflected on the side wall of the light passage hole that allows the light emitted from the light emitting layer to pass therethrough. By directly intersecting the emitted light 8 with 7, it is possible to increase the light amount, output, and intensity of the organic light emitting element at a position apart from the substrate surface by a certain distance.

When the taper angle of the light passage hole 5 is changed, the reflection angle of the light emission on the side wall of the light passage hole is changed, so that the position where the reflected light 7 and the directly emitted light 8 intersect is changed. In FIG. 4, the substrate thickness A is 0.2 mm, the first of the light passage holes is
Assuming that the radius B on the surface side is 0.02 mm and the relationship between the emission intensity and the directivity angle in the emission from the light emitting layer follows the Lambertian law, the taper angle of the light passage hole provided in the substrate is ± 4 to 12 °. The relationship between the distance D2 from the substrate surface and the relative emission intensity when the range is changed is shown.

As can be seen in FIG. 4, the taper angle (θ>
Not only in the case of 0) but also in the case where the light passage hole has a taper angle (θ <0) that narrows as it goes in the emission direction, by changing the taper angle of the light passage hole, it is possible to obtain a constant value from the substrate surface. It is possible to control the amount of light, the output, and the intensity of the organic light emitting element at a position separated by a distance of.

Thus, the substrate 1 of the organic light emitting device of the present invention
As a result of measuring the intensity of the light emission generated from the light emitting layer by changing the taper angle of the light passage hole provided in the, it was confirmed that the position where the intensity of the light emission is strengthened changes in response to the change in the taper angle. did it. The emission intensity of an organic light emitting device using a normal glass substrate shows a uniform decreasing tendency with respect to a change in distance from the substrate. That is, in the organic light emitting device of the present invention,
By changing the taper angle of the light passage hole 5 provided in the substrate 1, the distance from the substrate at the position where the emitted light reflected and emitted by the tapered portion and the emitted light that is directly emitted without being reflected by the tapered portion intersect is arbitrarily set. Adjustable, light intensity, power at this position,
It is possible to enhance the light emission characteristics such as and intensity.

Further, when the taper angle of the light passage hole provided in the substrate is made constant and the thickness of the substrate is changed, the amount of light reflected from the light emitting layer on the side wall of the light passage hole changes, The spread angle of emitted light and the amount of light propagating in the horizontal direction of the substrate and not emitted in the vertical direction of the substrate could be adjusted. As a result, it becomes possible to control the light emission extraction efficiency of the substrate 1 in the vertical direction. Furthermore, by changing the thickness of the substrate in this way, the distribution of the light that reaches and is reflected by the tapered portion and the light that is directly emitted without reaching the tapered portion in the light emitted from the light emitting layer is changed. To do. Therefore, even by the method of changing the thickness of the substrate in this way, the amount of light at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion,
It is possible to change the light emission characteristics such as output and intensity.

(Embodiment 2) FIG. 5 is a schematic sectional view showing a second embodiment of the organic light emitting device of the present invention. In this embodiment, the light passage hole is formed without penetrating the substrate. 5, the same reference numerals as those in FIG. 1 indicate the same parts. D1 indicates a processing depth of the light passage hole from the second surface side of the substrate.

In the present embodiment, by setting the processing depth D1, it is possible to adjust the distribution of the light passing through the light passage hole 5 and the light not passing through the light emitted from the light emitting layer. Therefore, also by this method, it is possible to control the light emission efficiency in the vertical direction of the substrate 1, and at the same time, at the position where the light reflected by the tapered portion intersects with the light emitted directly without reaching the tapered portion. It is also possible to change the light emission characteristics such as the light amount, the output, and the intensity.

It should be noted that the taper angle of the light passage hole and the substrate used in Embodiments 1 and 2 to control the light emission characteristics such as the amount of light, the output, and the intensity in a desired distance and region from the substrate. The same effect was obtained when any of the thicknesses and the working depths were combined or all of them were combined.

(Embodiment 3) This embodiment is one of the preferable embodiments in which a light-reflecting mirror layer is formed on the side wall of the light transmitting hole. That is, in the present invention, a mirror layer may be formed on the tapered portion in order to improve the reflectance. For the mirror layer, a metal such as Al having a high reflectance can be used. As a method of forming the mirror layer, for example,
Examples of the film forming method include vacuum deposition method, sputtering method, chemical vapor deposition method, and plating.

Further, a treatment with an additive or the like may be performed for mirror-finishing the taper portion or the mirror layer before forming the mirror layer.

As a result of measuring the light emission characteristics of the organic light emitting device of the present embodiment provided with the mirror layer, the organic light emitting device of the present embodiment has a wider spread angle of light emission than the organic light emitting device using the ordinary glass substrate. It was suppressed narrowly, and the light extraction efficiency in the vertical direction could be improved. Further, it was possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at the intersecting position of the emitted light reflected and emitted by the tapered portion and the emitted light directly emitted without being reflected by the tapered portion.

(Embodiment 4) This embodiment is the first embodiment of the light passage hole.
Focusing on the diameter on the surface side, the opening area is made larger than the area of the light emitting portion 6 so that the light generated from the light emitting layer can be efficiently introduced into the light passage hole 5.

As a result of measuring the light emitting characteristics of the organic light emitting device of the present embodiment, it is possible to efficiently introduce the light emitted from the light emitting layer into the light passing hole 5, so that the opening area of the light passing hole 5 on the first surface side is large. Is smaller than the area of the light emitting portion 6, it is possible to improve the light extraction efficiency in the substrate vertical direction,
Further, it was possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at the position where the reflected light at the tapered portion and the light emitted directly without being reflected at the tapered portion intersect.

(Embodiment 5) This embodiment is the first embodiment of the light passage hole.
This is one of the preferable forms having an optical resonator structure on the surface side.

FIG. 6 is a schematic view showing the organic light emitting device of this embodiment. (A) is a sectional view. (B) is a plan view of the second surface side. Although the configuration is almost the same as that of the first embodiment shown in FIG. 1, in the present embodiment, the substrate 1 and the first
An optical resonator 9 was produced between the electrode 2 and the emitted light to have directivity, thereby improving the emission efficiency to the outside.

The optical resonator 9 can be composed of, for example, a dielectric multilayer film, and SiO ₂ films and TiO ₂ films having different refractive indexes are alternately formed by magnetron sputtering to form 10 layers (5 layers for each film). A manufacturing method and the like in which they are laminated to form a multilayer film mirror may be mentioned. At this time, the respective film thicknesses of SiO ₂ and TiO ₂ are determined so that the resonator length becomes a wavelength at which the intensity of light emitted from the light emitting layer is the strongest.

In the organic light emitting device according to the present embodiment, by providing the resonator structure, the light extraction efficiency in the vertical direction of the substrate 1 can be improved as compared with the first, second and third embodiments, and the reflection at the taper portion can be achieved. It is possible to improve the light emission characteristics such as the light amount, output, and intensity at the position where the emitted light and the emitted light that is emitted directly without being reflected by the tapered portion intersect.

(Embodiment 6) This embodiment is the second embodiment of the light passage hole.
Equipped with an optical lens on the surface side, it collects the light emitted from the light passage hole,
It is one of the preferable forms of collimating or diverging.

FIG. 7 is a schematic view showing the organic light emitting device of this embodiment. (A) is a sectional view. (B) is a plan view of the second surface side. In FIG. 7, the same reference numerals as those in FIG. 1 denote the same members, and 10 denotes a spherical lens. The configuration is almost the same as that of the first embodiment shown in FIG. 1, but in the present embodiment, the spherical lens 10 is bonded to the second surface side of the further light passage hole 5. The spherical lens can be formed by molding an acrylic resin using a stamper that serves as a mold and bonding it to the back surface of the substrate.

In the organic light emitting device of this embodiment, by providing the spherical lens 10, the emission extraction efficiency in the vertical direction of the substrate 1 can be improved as compared with the first, second and third embodiments, and the reflection at the tapered portion can be improved. It was possible to improve the light emission characteristics such as the amount of light, the output and the intensity at the position where the emitted light and the emitted light which is emitted directly without being reflected by the tapered portion intersect.

(Embodiment 7) This embodiment is the second embodiment of the light passage hole.
Equipped with an optical lens on the surface side, it collects the light emitted from the light passage hole,
It is one of the preferable forms of collimating or diverging. The difference from the sixth embodiment is that a cylindrical lens is used as an optical lens.

FIG. 8 is a schematic view showing the organic light emitting device of this embodiment. (A) is a sectional view. (B) is a plan view of the second surface side. 8, the same reference numerals as those in FIG. 1 denote the same members, and 11 denotes a cylindrical lens.

In the present embodiment, it becomes possible to collect the component of the light emitted from the light passage hole 5 in the direction orthogonal to the arrangement direction.

(Embodiment 8) When the organic light emitting device according to the present invention is applied as a light emitting device array, as compared with a light emitting device array using a normal glass substrate, the light emission efficiency in the vertical direction of the substrate 1 and It was possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at any distance.

(Embodiment 9) A light projector to which the light emitting element array according to the present invention is applied has a higher light emission efficiency and a higher light emitting efficiency than the light projector using the light emitting element array using a normal glass substrate. It was possible to improve the light emission characteristics such as the amount of light, the output, and the intensity at any distance.

(Embodiment 10) A display device to which the organic light emitting device according to the present invention is applied has a light emission extraction efficiency and an arbitrary distance from the substrate as compared with a display device using an organic light emitting device using a normal substrate. It was possible to improve the light emission characteristics such as the amount of light, the output, and the intensity, and to improve the visibility and reliability.

(Embodiment 11) When the light emitting element array according to the present invention is applied to an optical writing device, as compared with a conventional optical writing device, the emission extraction efficiency in the vertical direction of the substrate 1 and at an arbitrary distance from the substrate are improved. Since the light emitting characteristics such as the light quantity, the output, and the intensity can be improved, the throughput and the reliability can be improved.

(Embodiment 12) The electrophotographic printer to which the optical writing device according to the present invention is applied has a light emission extraction of the writing device as compared with the electrophotographic printer using the optical writing device using a normal substrate. Since it is possible to improve the efficiency and the light emission characteristics such as the amount of light, the output, and the intensity at an arbitrary distance from the substrate, the throughput, the reliability, and the compactness can be realized.

[0092]

As described above, according to the present invention, it is possible to provide at low cost an organic light emitting device having high luminance in the direction perpendicular to the substrate and capable of high integration.

Further, by utilizing the reflected light at the side wall taper portion of the light passage hole provided on the substrate, it is possible to control the light amount, output and intensity of the organic light emitting element at a position apart from the substrate surface by a certain distance. it can.

Further, by introducing the optical resonator structure, it is possible to efficiently emit light to the outside with less waste.

In addition, by incorporating an optical lens in the organic light emitting device according to the present invention, it becomes possible to improve the light emitting efficiency and the light collecting efficiency.

Furthermore, the light emitting element array, the light projector, and the optical writing device to which the organic light emitting element according to the present invention is applied have high brightness and efficiency, and can control the light quantity, output, and intensity.

Further, in the display device to which the organic light emitting device and the light emitting device array according to the present invention are applied, the visibility and the reliability can be improved.

Further, in the electrophotographic printer to which the optical writing device according to the present invention is applied, throughput, reliability, and downsizing of the device can be realized.

[Brief description of drawings]

FIG. 1 is a schematic view showing a first embodiment of an organic light emitting device of the present invention. (A) is a sectional view. (B) is a plan view of the second surface side.

FIG. 2 is a diagram for explaining a method of controlling the amount of emitted light, the output, and the intensity by utilizing the reflected light on the side wall of the tapered light transmitting hole.

FIG. 3 is a graph showing a relationship between each parameter calculated by Expression (1) under a predetermined condition. (A) is a graph showing the relationship between the angle α and the distance D2. (B) is a graph showing the relationship between the distance D2 and the relative emission intensity.

FIG. 4 is a graph showing the results of calculating the relationship between the distance D2 and the relative light emission intensity at various taper angles.

FIG. 5 is a schematic sectional view showing a second embodiment of the organic light emitting device of the present invention.

FIG. 6 is a schematic view showing a fifth embodiment of the organic light emitting device of the present invention. (A) is a sectional view. (B) is a plan view of the second surface side.

FIG. 7 is a schematic view showing a sixth embodiment of the organic light emitting device of the present invention. (A) is a sectional view. (B) is a plan view of the second surface side.

FIG. 8 is a schematic view showing a seventh embodiment of the organic light emitting device of the present invention. (A) is a sectional view. (B) is a plan view of the second surface side.

FIG. 9 is a schematic cross-sectional view showing an example of a conventional organic light emitting device.

[Simple explanation of symbols]

1 substrate 1a First side 1b second side 2 First electrode 3 organic layers 4 Second electrode 5 Light passing hole 6 light emitting part 7 reflected light 8 Direct output light 9 Optical resonator 10 Spherical lens 11 Cylindrical lens 111 substrate 112 transparent electrode 113 organic layer 114 back electrode

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/14 33/24 F term (reference) 2C162 AE28 AE47 AG01 AH45 AH47 AH65 AH68 FA04 FA16 FA23 FA46 3K007 AB02 AB03 BB06 DB03

Claims (20)

[Claims] 1. A light emitting portion, which is formed by laminating a transparent first electrode, an organic layer including a light emitting layer made of an organic light emitting material, and a second electrode on at least one surface of a substrate. There is one or more, and a light passage hole having a taper is formed in the substrate at a position corresponding to the light emitting portion, and the light emitted from the light emitting layer is passed through the light passage hole to the first surface of the substrate. An organic light emitting device characterized in that the light is emitted to the outside from the side of the second surface which is the opposite side. 2. The organic light emitting device according to claim 1, wherein the light passage hole is formed so that a diameter of the second surface side is larger than a diameter of the first surface side. element. 3. The organic light emitting device according to claim 1, wherein the light passage hole is formed so that a diameter of the first surface side is larger than a diameter of the second surface side. element. 4. The organic light emitting device according to claim 1, further comprising a light-reflecting mirror layer formed on a side wall of the light passage hole. 5. The area of the end portion of the light passage hole on the first surface side is larger than the area of the light emitting portion, according to any one of claims 1 to 4. Organic light emitting device. 6. The organic light emitting device according to claim 1, further comprising an optical resonator structure on the first surface side of the light passage hole. 7. The organic light emitting device according to claim 1, further comprising an optical resonator structure on the second surface side of the light passage hole. 8. The organic light emitting device according to claim 1, further comprising an optical lens on the second surface side of the light passage hole. 9. The organic light emitting device according to claim 8, wherein the optical lens is a spherical lens. 10. The organic light emitting device according to claim 8, wherein the optical lens is a cylindrical lens. 11. One of claims 1 to 10.
A light-emitting element array comprising the organic light-emitting element according to the item. 12. The method according to any one of claims 1 to 10.
A floodlight comprising the organic light-emitting device according to the item 1. 13. A floodlight comprising the light emitting element array according to claim 11. 14. One of claims 1 to 10.
A display device comprising the organic light emitting device according to the item 1. 15. A display device comprising the light emitting device array according to claim 11. 16. An optical writing device comprising the light emitting element array according to claim 11. Description: 17. The method according to any one of claims 1 to 10.
An electrophotographic printer comprising the organic light-emitting device according to the item. 18. An electrophotographic printer comprising the light emitting element array according to claim 11. 19. An electrophotographic printer, comprising the display device according to claim 14 or 15. 20. An electrophotographic printer, comprising the optical writing device according to claim 16.