JP2007072031A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of dividing a picture and projecting the divided pictures on a screen. <P>SOLUTION: The projector includes: projection lenses 14 and 16; a lamp 40; a color wheel 50; a light tunnel 60; a condenser lens 70; fold mirrors 80, 82, 84 and 86; a DMD 90; first and second shutters 100 and 102; and a shutter switching device 110. Light in an on-state from the DMD 90 is reflected in a direction R1 and made incident on the projection lens 14 through the first shutter 100, and light in an off-state is reflected in a direction R2 and made incident on the projection lens 16 through the second shutter 102. The first and the second shutters 100 and 102 are controlled according to a normal mode or an enlarging mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector, and more particularly, to a projector using a plurality of projection lenses.

  Front-projection or rear-projection projectors that project images such as televisions and DVDs have been put into practical use. In a projector, a liquid crystal or a DMD (Digital Micro-mirror Device) is used as a modulation element that spatially modulates image data.

  In the DMD, each pixel arranged two-dimensionally is composed of a minute mirror, and the tilt angle of the mirror is controlled by an electrostatic field effect by a memory element arranged immediately below each pixel to change the reflection angle of reflected light. Thus, it is a reflective display element that creates an on / off state.

  When the pixel is off, reflected light from the mirror (hereinafter referred to as off-light) does not enter the projection lens, and when the pixel is on, reflected light from the mirror (hereinafter referred to as on-light) enters the projection lens, and the screen Optical system parts are arranged so as to form an image. The inclination angle of the ON light of each mirror is determined to be about 10 to 12 degrees with respect to the incident surface of the DMD light.

  For example, as disclosed in Patent Document 1, a projector using DMD projects light from a light source onto a rotating color wheel, and R (red), G (green), and B (blue) separated by the color wheel. ) Are sequentially illuminated on the DMD, and the light reflected by the DMD is projected on the screen via the projection lens.

  Projectors are required to project a large screen brighter and clearer. In order to satisfy this, a design has been made to make the projection lens of the projector a short focus. Patent Document 2 discloses that the liquid crystal display element side is telecentric, has a long back focus, has a bright F-number, and has a 100-inch projection distance of 2 on the short focus side while having good aberration characteristics, high contrast, and high resolving power. A wide-angle zoom lens for a three-plate color projector of about 5 m is disclosed.

  Patent Document 3 discloses a zoom lens suitable for a liquid crystal projector that corrects various aberrations associated with zooming and has good optical performance over the entire screen.

JP 2004-294985 A JP 2001-249275 A

  In order to increase the size of an image projected from a projector, a zoom lens for a projector in which aberration is corrected as disclosed in Patent Document 2 and Patent Document 3 is disclosed. For example, it is difficult to project an image having a focal length of 1 meter and 60 inches, and in this case, designing a projection lens is also very difficult.

An object of the present invention is to provide a projector capable of projecting a large screen while facilitating the design of a short focus of a projection lens.
A further object of the present invention is to provide a projector that can divide and project an image on a screen.

  A projector according to the present invention includes a light source, a modulation unit that modulates light from the light source, and a plurality of projection lenses that respectively receive light from the modulation unit and emit projection light. As the light source, a discharge lamp such as a mercury lamp or a xenon lamp may be used, or a semiconductor diode or a semiconductor laser diode may be used.

  The modulation means includes a reflective display element in which a plurality of mirrors arranged in a two-dimensional array are formed, and each mirror is selectively driven to a first tilt angle and a second tilt angle, The projection lens enters the reflected light of the mirror at the first tilt angle, and the second projection lens enters the reflected light of the mirror at the second tilt angle. The reflective display element is preferably a DMD.

  The modulation means modulates each mirror based on the first image data during the first period, causes the reflected light of the mirror at the first tilt angle to enter the first projection lens, and outputs the second period. At this time, each mirror is driven based on the second image data, and the reflected light of the mirror at the second tilt angle is incident on the second projection lens.

  Preferably, the projector includes a shutter that transmits or blocks light between the modulation unit and the plurality of projection lenses, and the shutter blocks light incident on the second projection lens during the first period. In the second period, the incident light to the first projection lens is shielded. The shutters can be arranged on the incident side of the projection lens, and each shutter is controlled according to the operation mode (normal mode, enlargement mode). In the normal mode, incident light to one projection lens selected from the plurality of projection lenses is transmitted, and an image is projected therefrom. As the shutter, for example, an optical liquid crystal shutter or a mechanical shutter can be used.

  Preferably, the projector includes position changing means for changing a position in a two-dimensional direction orthogonal to the optical axis of at least one of the plurality of projection lenses. The position variable means may be either mechanical or electric.

  Preferably, the first and second projection lenses are arranged symmetrically with respect to the optical axis of the reflective display element. This facilitates optical design of the first and second projection lenses.

  More preferably, the projection image is formed by combining the first projection light projected by the first projection lens and the second projection light projected by the second projection lens. The projection image may be one that recognizes one image by combining the first projection light and the second projection light, or may recognize images having different meanings.

  According to the present invention, since projection is performed using a plurality of projection lenses, it is easy to design a short focus projection lens and it is possible to project a bright image on a large screen. For example, when considering a 60-inch projection display with a focal length of 1 meter, it is possible to display 30 inches per projection lens unit, so it is not necessary to use an extremely large curvature lens, and aberration correction is easy. It becomes. Furthermore, when an image is synthesized in a time division manner using projection light from a plurality of projection lenses, the apparent resolution can be improved.

  Hereinafter, a preferred configuration of a projector according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of a front projection type projector according to an embodiment of the present invention. Two projection lenses (or projection lens units) 14 and 16 for projecting an image enlarged by the zoom function are attached to the front surface 12 of the projector 10. An exhaust port 18 including a plurality of slits for exhausting warm air inside to the outside is formed between the projection lenses 14 and 16. On the upper surface 20 of the projector, an operation button 22 for inputting a power switch, a display mode, and the like is attached. As the projection lenses 14 and 16, only one projection lens or both projection lenses can be used depending on the operation mode. In the latter case, it is possible to combine the images projected by the projection lenses 14 and 16 and display one image on the screen.

  FIG. 2 is a schematic diagram illustrating an optical system in the projector. The projector 10 includes a lamp 40 with a condensing mirror, a color wheel 50, a light tunnel 60, a condenser lens 70, a plurality of folding mirrors 80, 82, 84, 86, a DMD 90, first and second shutters in a housing 30. 100 and 102 and two projection lenses 14 and 16 are included.

  The lamp 40 has a spheroid mirror 42 as a condensing mirror and a discharge lamp 44 attached in the optical axis direction. For example, a xenon lamp, a mercury lamp, a metal halide lamp, or the like can be used as the discharge lamp. The arc (light emitting point) of the discharge lamp 44 is condensed by the condensing mirror 42, and the color wheel 50 and the light tunnel 60 are arranged at a position where the condensed light converges.

  As is well known, the color wheel 50 is a rotation in which the annular zone is divided into three primary colors of light (red (R), green (G), blue (B), or red, green, blue, white (W)). Including possible filters, the color wheel is rotated by a motor. Light from the lamp 40 enters the color filter 50 substantially perpendicularly, and R, G, B, or W light is sequentially emitted from the color wheel 50.

  A light tunnel 60 is arranged along the optical axis of the lamp 40 in the vicinity of the color wheel 50. The R, G, and B light emitted from the color wheel 50 is incident on the light tunnel 60, and a light beam with uniform intensity is emitted from the end.

  The light beam from the light tunnel 60 illuminates the mirror area of the DMD 90 array via the condenser lens 70 and the folding mirrors 80 and 82. Each mirror of the DMD 90 is variably controlled in inclination angle independently. When the mirror is at the first tilt angle, the incident light illuminated by the folding mirror 82 is reflected in the R1 direction, and this R1 direction coincides with the optical axis C1 of the projection lens 14. When the mirror is at the second tilt angle, the incident light illuminated by the folding mirror 82 is reflected in the R2 direction. The reflected light is reflected by the folding mirror 84 and is incident on the projection lens 16 by the folding mirror 86. The folding mirrors 80, 82, 84, 86 may be plane mirrors or spherical mirrors.

  A first shutter 100 is disposed between the DMD 90 and the projection lens 14, and a second shutter 102 is disposed between the folding mirror 86 and the projection lens 16. The operations of the first and second shutters 100 and 102 are controlled by drive signals S1 and S2 from the shutter switching device 110. As the first and second shutters 100 and 102, for example, an optical liquid crystal shutter or a mechanical shutter can be used.

  FIG. 3 is a block diagram showing an electrical configuration of the projector. The projector drives an image memory 200 that stores RGB digital image data having a format plane corresponding to the number of pixels of the DMD 90, a control unit 210 that controls the DMD 90 and other circuits based on the image data of the image memory 200, and the lamp 40. A lamp driving circuit 220 for controlling and a color wheel driving unit 230 for controlling the rotation of the motor of the color wheel 50 are included. The control unit 210 stores programs and data necessary for the operation of the projector in a memory, and executes control of each unit according to them.

  Next, the operation of the projector will be described with reference to the flowchart of FIG. The projector according to the present embodiment includes a normal mode in which one projection lens is used for projection and an enlargement mode in which two projection lenses are used for projection. The selection of these modes can be input from the operation panel 22 by the user, for example.

  The control unit 210 confirms the operation mode of the normal mode or the enlargement mode (step S101). When in the normal mode (step S102), the control unit 210 controls the shutter switching device 110 so that the first shutter 100 always transmits light and the second shutter 102 always blocks light. (Step S103). This control is performed by the drive signals S1 and S2.

  After the lamp 40 is turned on, R, G, B, or W light is sequentially emitted from the color wheel 50, and the DMD 90 is illuminated by these lights. The DMD 90 drives each mirror in synchronization with R, G, B, or W. Incident light is reflected in the R1 direction by the mirror driven to the first tilt angle, that is, the mirror in the ON state, and this reflected light is incident on the projection lens 14, where it is magnified and displayed on the screen (step S104). On the other hand, the light reflected in the R2 direction by the mirror driven to the second tilt angle, that is, the mirror in the OFF state, is blocked by the shutter 102 via the folding mirrors 84 and 86. For this reason, an image is not projected from the projection lens 16.

  On the other hand, when in the enlargement mode (step S105), the controller 210 complementarily drives the first shutter 100 and the second shutter 102 via the shutter switching device 110, and one of the shutters transmits light. During this period, the other shutter is controlled to block the light (step S106). The control unit 210 further reads out the image data to be projected by the projection lens 14 and the image data to be projected by the projection lens 16 from the image memory 200 at a timing synchronized with the first and second shutters 100 and 102, and causes the DMD 90 to operate. To drive. Thus, the image is not projected from the projection lens 16 while the image is projected by the projection lens 14, and the image is projected from the projection lens 16 while the image is not projected from the projection lens 14 (step S107).

  FIG. 5 is a timing chart in the enlargement mode. When one frame time of the image projected on the screen by the DMD is Tf, the one frame time Tf is divided into j periods t1, t2, t3, t4,... Tj (t1 = t2 = t3 = ... = tj). The periods t1, t2,... Tj are determined, for example, by counting a predetermined number of clocks of the internal clock signal. In addition, R, G, B, and W are emitted every time the color wheel 50 makes one rotation, and each of the periods t1, t2,..., Tj corresponds to K sets of R, G, and K corresponding to K rotation of the color wheel 50. B, W.

  In the period t1, the controller 210 reads the image data D1 from the image memory 200 and drives the DMD 90 based on the image data D1. In addition, the shutter switching device 110 outputs the drive signals S1 and S2 to the first and second shutters 100 and 102, and in the period t1, the first shutter 100 is set to the transmission state and the second shutter 102 is set to the light shielding state. To.

  Of the mirrors of the DMD 90, the reflected light of the mirror at the first tilt angle is incident on the projection lens 14 via the first shutter 100, and an image corresponding to the image data D1 is projected on the screen. On the other hand, the reflected light of the mirror at the second tilt angle is shielded by the second shutter 102 and no image is projected from the projection lens 16.

  Next, in the period t2, the control unit 210 reads the image data D2 from the image memory 200, and drives the DMD 90 based on the image data D2. Further, the shutter switching device 110 outputs drive signals S1 and S2 so that the first shutter 100 is in a light shielding state and the second shutter 102 is in a light transmitting state. Thereby, the reflected light of the mirror at the first tilt angle among the mirrors of the DMD 90 is shielded by the first shutter 100, and no image is projected from the projection lens 14. The reflected light of the mirror at the second tilt angle is incident on the projection lens 16 via the folding mirrors 84 and 86 and the second shutter 102, and an image corresponding to the image data D2 is projected. In the next period t3, as in the period t1, an image is projected from the projection lens 14, and no image is projected from the projection lens 16. In the period t4, as in the period 2, the image is not projected from the projection lens 14 and the image is projected from the projection lens 16. In this way, images corresponding to the image data D1 and D2 are alternately projected from the projection lenses 14 and 16 in one frame period.

  FIG. 6 is a diagram for explaining an example of reading data from the image memory. The image memory 200 is configured using, for example, a frame memory such as a FIFO or a synchronous dynamic memory. Preferably, the image memory includes a plurality of banks, and each bank stores image data corresponding to the number of pixels of DMD 90, that is, frame data. When the DMD is composed of M rows × N columns of mirrors (pixels), if the projector is in the normal mode, the control unit 210, as shown in FIG. 6, the image data P1, P2 corresponding to M × N for each frame, as shown in FIG. Is read. In the enlargement mode, for example, the control unit 210 alternately reads odd frames that store the image data D1 and even frames that store the image data D2.

  FIG. 7 is a diagram illustrating a display example of the screen in the enlargement mode. FIG. 7A shows an example in which an image 242 produced by projection light from the projection lens 14 and an image 244 produced by projection light from the projection lens 16 are combined on the screen 240. The example in the figure is an example in which alphabets “A” are combined and displayed. By configuring one screen size using the two projection lenses 14 and 16, the image size of one projection lens can be halved. As a result, a large image can be displayed with a short focal point, and the design of the projection lens can be facilitated.

  Further, as an application example of the display image of the projector, as shown in FIG. 7B, images 246 and 248 projected by the projection lenses 14 and 16 may have different contents. In the illustrated example, the projection lens 14 displays “B”, and the projection lens 16 displays “C”. For example, when a plurality of pages are projected in a presentation, two pages may be displayed on the images 246 and 248 simultaneously. Alternatively, an image may be displayed on the image 246 and text may be displayed on the image 248. In this case, two image memories are prepared, image data corresponding to the image 246 is stored in one image memory, image data corresponding to the image 248 is stored in the other image memory, and image data from each image memory is stored. You may make it read alternately.

  FIG. 8 is a diagram illustrating a configuration example of the shutter. As shown in FIG. 8, the shutter 104 includes a disk having a transmission region 250 and a light-shielding region (non-transmission region) 252, and a motor that rotates the disk. In the normal mode, the shutter switching device 110 fixes the shutter 104 so that the transmission region 250 is positioned on the incident optical axis C1 of the projection lens 14 and the light shielding region 252 is positioned on the incident optical axis C2 of the projection lens 16. To do. In the enlargement mode, the shutter switching device 110 rotates the motor at a timing synchronized with the periods t1, t2,... Tj shown in FIG. 5, and alternately projects the transmissive region 250 and the light shielding region 252 with the projection lens 14. The lens 16 is positioned on the incident optical axes C1 and C2.

  FIG. 9 is a diagram showing an optical system of the projector according to the second embodiment of the present invention. In the second embodiment, the projection lens 14 and the projection lens 16 are close to each other. As a result, the number of folding mirrors is one less than that in the first embodiment.

  FIG. 10 is a diagram showing an optical system of a projector according to the third embodiment of the present invention. In the third embodiment, a moving mechanism 300 for moving the projection lens 16 in a two-dimensional direction orthogonal to the optical axis C2 is provided. The moving mechanism 300 unitizes the projection lens 16, the second shutter 102, and the folding mirror 84, and enables them to move in the horizontal direction and the vertical direction. The moving mechanism 300 is configured using known means. For example, a moving mechanism that moves in the horizontal and vertical directions using a screw mechanism, a moving mechanism that uses a motor, a moving mechanism that uses a slide mechanism, and the like can be used. .

  When the projection position of the projection lens 16 in the two-dimensional direction can be adjusted, as shown in FIGS. 7A and 7B, when the image by the projection lens 14 and the projection lens 16 is displayed on the screen, the image The boundary between 242 and 244 and the boundary between image 246 and image 148 can be aligned. The projection lens 14 together with the projection lens 16 may be movable in a two-dimensional direction. Furthermore, in the third embodiment, the light converged by the lamp 40 enters the light tunnel 60 and then enters the color wheel 50.

  FIG. 11 is a diagram showing an optical system of a projector according to the fourth and third embodiments of the present invention. In the fourth embodiment, the projection lens 14 and the projection lens 16 are arranged symmetrically with respect to the central axis C3 of the DMD 90 in order to facilitate the design of the projection lens and the optical system. The light from the color wheel 50 illuminates the DMD 90 by the folding mirrors 80 and 82. In each mirror of the DMD 90, the reflected light of the mirror at the first tilt angle is reflected in the R1 direction, and the optical axis C1 is reflected by the folding mirror 84. And is incident on the projection lens 14. On the other hand, the reflected light of the mirror at the second tilt angle is reflected in the R2 direction, reflected by the folding mirror 86 in the direction parallel to the optical axis C2, and incident on the projection lens 16. The operations of the first and second shutters 100 and 102 in the normal mode and the enlargement mode are the same as in the above embodiment.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Modifications and changes are possible.

  In the above embodiment, the light tunnel is used to make the intensity of light from the lamp uniform, but an optical integrator may be used. Moreover, although the several folding mirrors 80-86 were used for the illumination optical system and the projection optical system, you may comprise using a lens or a prism in addition to this. Further, the lamp 40 may use a light source such as a semiconductor laser diode other than the discharge lamp. Furthermore, although the first and second shutters are arranged on the incident side of the projection lens, they may be arranged in other optical paths.

  The projector according to the present invention is used as an image display device for projecting a video such as a television or a DVD.

1 is a perspective view showing an external configuration of a projector according to an embodiment of the invention. It is a figure which shows the optical system of the projector of a present Example. It is a block diagram which shows the electric constitution of the projector of a present Example. It is a flowchart explaining operation | movement of the projector of a present Example. It is an operation | movement timing chart of each part of a projector. It is a figure explaining the example of reading of an image memory. It is a figure explaining the example of a display by a projector. It is a figure which shows the structural example of a 1st, 2nd shutter. It is a figure which shows the optical system of the projector which concerns on the 2nd Example of this invention. It is a figure which shows the optical system of the projector which concerns on the 3rd Example of this invention. FIG. 6 is a diagram illustrating an optical system of a projector according to a fourth embodiment of the invention.

Explanation of symbols

10: Projector 12: Front surface 14, 16: Projection lens 20: Upper surface 22: Operation button 30: Housing 40: Lamp 50: Color wheel 60: Light tunnel 70: Condenser lenses 80-86: Folding mirror 90: DMD
100: first shutter 102: second shutter 110: shutter switching device 300: moving mechanism

Claims (14)

A projector having a light source, a modulation unit that modulates light from the light source, and a plurality of projection lenses that respectively receive light from the modulation unit and emit projection light. The modulation means includes a reflective display element in which a plurality of mirrors arranged in a two-dimensional array are constrained, and each mirror is selectively driven to a first tilt angle and a second tilt angle, 2. The projector according to claim 1, wherein the first projection lens receives the reflected light of the mirror at the first tilt angle, and the second projection lens receives the reflected light of the mirror at the second tilt angle. . The modulation means drives each mirror based on the first image data during the first period, causes the reflected light of the mirror at the first tilt angle to enter the first projection lens, and the modulation means 3. The projector according to claim 1, wherein, during the period of 2, each mirror is driven based on the second image data, and the reflected light of the mirror at the second inclination angle is incident on the second projection lens. The projector further includes a shutter that transmits or blocks light between the modulation unit and the plurality of projection lenses, and the shutter blocks light incident on the second projection lens during the first period, The projector according to any one of claims 1 to 3, wherein light incident on the first projection lens is shielded during the second period. 5. The projector according to claim 1, further comprising: an operation mode determination unit that determines an operation mode; and a shutter control unit that controls a shutter according to a determination result of the operation mode determination unit. When the operation mode determination unit determines that the normal mode is selected, the shutter control unit transmits the incident light to one of the plurality of projection lenses, and blocks the incident light to the other projection lens. A projector according to any one of claims 1 to 5. When it is determined by the operation mode determination means that the mode is not the normal mode, the shutter control means shields the incident light to the second projection lens when the incident light is transmitted to the first projection lens, and the first projection lens The projector according to claim 1, wherein when the incident light is shielded, the incident light of the second projection lens is transmitted. The projector according to any one of claims 1 to 7, further comprising input means for inputting selection of an operation mode. The projector according to any one of claims 1 to 8, wherein a plurality of shutters are respectively disposed on the incident sides of the plurality of projection lenses. 10. The projector according to claim 1, further comprising a position varying unit configured to vary a position in a two-dimensional direction orthogonal to the optical axis of at least one projection lens of the plurality of projection lenses. The projector according to claim 1, wherein the first and second projection lenses are arranged symmetrically with respect to the central axis of the reflective display element. The projector according to claim 1, wherein the projection image is configured by combining the projection light projected by the first projection lens and the projection light projected by the second projection lens. The projector further includes a color wheel between the light source and the modulation unit, and the color wheel selects light of red, green, and blue wavelengths from the light of the light source, and sequentially selects the light of each selected wavelength as the modulation unit. The projector according to claim 1, which outputs the projector. The first and second projection lenses are arranged such that their optical axes are parallel to each other, and the first and second projection lenses are attached to one surface of the projector main body. The projector according to one

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