JP5979481B2 - Illumination device, projection device, and projection-type image display device - Google Patents

Description

  The present invention provides an illumination device using a plurality of coherent lights having different wavelength ranges, a projection device that projects a plurality of coherent lights having different wavelength ranges, and displaying an image using a plurality of coherent lights having different wavelength ranges. The present invention relates to a projection-type image display device, and more particularly to an illumination device, a projection device, and a projection-type image display device capable of making speckles inconspicuous.

  Projection-type image display devices having a screen and a projection device that projects image light on the screen are widely used. In a typical projection-type image display device, an original two-dimensional image is generated by using a spatial light modulator such as a liquid crystal micro display or a DMD (Digital Micromirror Device), and the two-dimensional image is projected into an optical system. An image is displayed on the screen by enlarging and projecting on the screen using the system.

  Various types of projectors have been proposed, including commercially available products called “optical projectors”. In general optical projectors, a spatial light modulator such as a liquid crystal display is illuminated using a lighting device consisting of a white light source such as a high-pressure mercury lamp, and the resulting modulated image is projected onto a screen using a lens. Adopted. For example, in JP2004-264512A, white light generated by an ultra-high pressure mercury lamp is divided into three primary color components of R, G, and B by a dichroic mirror, and these lights are guided to a spatial light modulator for each primary color. A technique is disclosed in which a modulated image for each primary color is synthesized by a cross dichroic prism and projected onto a screen.

  However, high-intensity discharge lamps such as high-pressure mercury lamps have a relatively short life, and when used in optical projectors or the like, it is necessary to frequently replace the lamps.

  In order to cope with such a problem, a method using a coherent light source such as a laser has been proposed. For example, a semiconductor laser widely used in the industry has a very long life compared to a high-intensity discharge lamp such as a high-pressure mercury lamp. Further, since the light source can generate light of a single wavelength, there is an advantage that the entire apparatus can be reduced in size.

  On the other hand, a method using a coherent light source such as a laser beam has a new problem such as generation of speckle. Speckle is a speckled pattern that appears when a scattering surface is irradiated with coherent light such as laser light. When speckle is generated on a screen, it is observed as speckled brightness unevenness, that is, brightness unevenness. It becomes a factor having a physiological adverse effect on the person. The reason why speckles occur when coherent light is used is that coherent light reflected by each part of a scattering reflection surface such as a screen interferes with each other because of its extremely high coherence. . For example, the document “Speckle Phenomena in Optics, Joseph W. Goodman, Roberts & Co., 2006” provides a detailed theoretical discussion of speckle generation.

  As described above, in the system using the coherent light source, a problem inherent to the generation of speckles occurs, and thus a technique for suppressing the generation of speckles has been proposed. For example, JP6-208089A has a technology for reducing speckles by irradiating a scattering plate with laser light, guiding scattered light obtained therefrom to a spatial light modulator, and rotating the scattering plate by a motor. It is disclosed.

  However, in the method disclosed in the above-mentioned JP6-208089A, the laser beam is irradiated to the scattering plate to be scattered, so that part of the laser beam is wasted without contributing to the video display at all. Moreover, although it is necessary to rotate a scattering plate for speckle reduction, such a mechanical rotation mechanism becomes a comparatively large apparatus, and also power consumption becomes large. Furthermore, even if the scattering plate is rotated, the position of the optical axis of the illumination light does not change, so that speckles generated due to diffusion on the screen cannot be sufficiently suppressed.

JP 2004-264512 A Japanese Patent Laid-Open No. 6-208089

Speckle Phenomena in Optics, Joseph W. Goodman, Roberts & Co., 2006

  Incidentally, coherent light generated from a single light source is typically monochromatic light, as represented by laser light. Further, coherent light generated from a practical light source is limited to light of a specific wavelength (range). On the other hand, in many cases today, it is desirable to illuminate the illuminated area or display an image in a desired color that cannot be displayed with a single light source, or in multiple colors, typically full color. It is rare. Therefore, the illumination device, the projection device, and the projection-type image display device that are actually developed use a plurality of coherent lights having different wavelength ranges in order to cope with various applications today.

  In addition, in many conventional projection devices and projection-type image display devices, typically conventional large-scale projection devices and projection-type image display devices, more specifically, for the purpose of uniform light intensity distribution, For the purpose of uniformly illuminating the entire surface of the spatial light modulator, an integrator rod is provided upstream of the spatial light modulator. Therefore, it would be very convenient if the above-described solution for making speckles inconspicuous could be used in combination with an integrator rod.

  The present invention has been made in consideration of the above points, and is an illumination device that illuminates using a plurality of coherent lights having different wavelength ranges and incorporates an integrator rod, and makes speckles inconspicuous. It is an object of the present invention to provide an illumination device that can perform the above-described operation, and to provide a projection device and a projection-type image display device that include the illumination device.

The lighting device according to the present invention comprises:
An optical element including a first light diffusing element and a second light diffusing element;
First coherent light in a first wavelength region scans on the first light diffusing element, and second coherent light in a second wavelength region different from the first wavelength region scans on the second light diffusing element. And an irradiation device that irradiates the optical element with a plurality of coherent lights having different wavelength ranges,
A synthesis device that synthesizes the first coherent light from the first light diffusing element and the second coherent light from the second light diffusing element;
An integrator rod on which the first coherent light and the second coherent light synthesized by the synthesizing apparatus are incident.

In the lighting device according to the present invention,
The first coherent light incident on each position of the first light diffusing element from the irradiation device illuminates a region overlapping at least in part after exiting from the integrator rod,
The second coherent light incident on each position of the second light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
The at least part illuminated so as to overlap with the first coherent light and the at least part illuminated so as to overlap with the second coherent light may be at least partially overlapped.

In the lighting device according to the present invention,
A region on the incident surface of the integrator rod on which the first coherent light incident on each position of the first light diffusing element is incident overlaps at least in part.
The region on the incident surface of the integrator rod on which the second coherent light incident on each position of the second light diffusing element is incident may overlap at least partially.
In such an illuminating device according to the present invention, the at least part of the incident surface of the integrator rod on which the first coherent light is incident so as to overlap with the incident of the integrator rod on which the second coherent light is incident so as to overlap. The at least part of the surface may overlap at least partially.

  In the illumination device according to the present invention, the first coherent light incident on each position of the first light diffusing element is incident on the same region on the incident surface of the integrator rod, and the second light diffusing element The second coherent light incident on each position may be incident on the same region on the incident surface of the integrator rod. In the illumination device according to the present invention, the same region on the entrance surface of the integrator rod on which the first coherent light is incident and the same region on the entrance surface of the integrator rod on which the second coherent light is incident are: , May at least partially overlap or be identical.

In the lighting device according to the present invention,
The optical element further includes a third light diffusing element different from the first light diffusing element and the second light diffusing element,
The plurality of coherent lights with different wavelength ranges emitted from the irradiation device further include third coherent light in a third wavelength range different from the first wavelength range and the second wavelength range, Irradiating the third coherent light so that the third coherent light scans on the third light diffusing element;
The third coherent light from the third light diffusing element is combined with the first coherent light from the first light diffusing element and the second coherent light from the second light diffusing element by the combining device. You may be made to do.

  In the lighting device according to the present invention, the first wavelength range corresponds to a first primary color component, the second wavelength range corresponds to a second primary color component, and the third wavelength range corresponds to a third primary color component. You may do it.

In the lighting device according to the present invention,
The first coherent light incident on each position of the first light diffusing element from the irradiation device illuminates a region overlapping at least in part after exiting from the integrator rod,
The second coherent light incident on each position of the second light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
The third coherent light incident on each position of the third light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
The at least a portion illuminated to overlap by the first coherent light, the at least a portion illuminated to overlap by the second coherent light, and the at least a portion illuminated to overlap by the third coherent light are: Or at least partially overlap.

In the lighting device according to the present invention,
A region on the incident surface of the integrator rod on which the first coherent light incident on each position of the first light diffusing element is incident overlaps at least in part.
A region on the incident surface of the integrator rod on which the second coherent light incident on each position of the second light diffusing element is incident overlaps at least in part,
The region on the incident surface of the integrator rod on which the third coherent light incident on each position of the third light diffusing element is incident may overlap at least partially.
In such an illuminating device according to the present invention, the at least part of the incident surface of the integrator rod on which the first coherent light is incident so as to overlap with the incident of the integrator rod on which the second coherent light is incident so as to overlap. The at least part on the surface and the at least part on the incident surface of the integrator rod on which the third coherent light is incident so as to overlap may be at least partially overlapped.

In the lighting device according to the present invention,
The first coherent light incident on each position of the first light diffusing element is incident on the same region on the incident surface of the integrator rod,
The second coherent light incident on each position of the second light diffusing element is incident on the same region on the incident surface of the integrator rod,
The third coherent light incident on each position of the third light diffusing element may be incident on the same region on the incident surface of the integrator rod.
In the illumination device according to the present invention, the same region on the entrance surface of the integrator rod on which the first coherent light is incident and the same region on the entrance surface of the integrator rod on which the second coherent light is incident. And the same region on the entrance surface of the integrator rod on which the third coherent light is incident may overlap at least partially or be the same.

  In the illumination device according to the present invention, the light diffusing elements included in the optical element may be arranged on one plane.

  In the illumination device according to the present invention, each light diffusing element may be a hologram.

  In the illumination device according to the present invention, each light diffusing element may be a computer-generated hologram.

  In the illumination device according to the present invention, each light diffusing element may be a Fourier transform hologram.

  In the illumination device according to the present invention, each light diffusing element may be a lens array.

  In the illumination device according to the present invention, each light diffusing element may be a transmissive light diffusing element.

  In the illumination device according to the present invention, an entrance surface of the integrator rod may be connected to the synthesis device.

In the illuminating device according to the present invention, the irradiating device includes a light source mechanism that generates a combined light obtained by combining a plurality of coherent lights having different wavelength ranges, and a scanning that changes a traveling direction of the combined light from the light source mechanism. You may make it have a device and the separation apparatus which isolate | separates the said synthesized light from the said scanning device into the several coherent light from which the said wavelength range differs.
In such an illumination apparatus according to the present invention, the light source mechanism includes a plurality of light sources that respectively generate coherent light in each wavelength region, and a combining device that combines the coherent lights from the plurality of light sources. Also good.

  In the illumination device according to the present invention, the irradiation device is provided corresponding to each of a plurality of light sources that respectively generate a plurality of coherent lights having different wavelength ranges, and a coherent light from each light source, and a coherent light from the corresponding light source. A plurality of scanning devices that change the traveling direction of light so that the coherent light scans the corresponding light diffusing element may be included.

  In the illumination device according to the present invention, the irradiation device changes a traveling direction of the coherent light from the plurality of light sources that respectively generate the plurality of coherent lights having different wavelength ranges, and the coherent light is generated. A plurality of coherent lights having different wavelength ranges incident on the same scanning device from different directions and changing their traveling directions in different directions. May be allowed.

The projection apparatus according to the present invention
Any of the lighting devices according to the invention described above;
A spatial light modulator illuminated by light emitted from the integrator rod.

A projection-type image display device according to the present invention includes:
Any of the projection devices according to the invention described above;
And a screen on which the modulated image obtained by the spatial light modulator is projected.

  ADVANTAGE OF THE INVENTION According to this invention, when a several coherent light from which a wavelength range mutually differs is projected with the illuminating device incorporating the integrator rod, a speckle can be made effectively inconspicuous.

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a diagram showing a schematic configuration of an illumination device, a projection device, and a projection type video display device. FIG. 2 is a diagram showing a light diffusing element included in the illumination device shown in FIG. 1 and a portion of an incident surface that receives coherent light from the light diffusing element of the synthesizer. It is a figure for demonstrating an example of the optical characteristic of an element. FIG. 3 is a diagram corresponding to FIG. 2 for explaining another example of the optical characteristics of the light diffusing element. FIG. 4 is a diagram corresponding to FIG. 2 for explaining still another example of the optical characteristics of the light diffusing element. FIG. 5 is a view for explaining an exposure method for producing a light diffusing element composed of a transmission volume hologram exhibiting the optical characteristics of FIG. FIG. 6 is a perspective view for explaining the operation of the lighting device shown in FIG. FIG. 7 is a diagram corresponding to FIG. 1 and is a diagram for explaining a modification of the illumination device, the projection device, and the projection type video display device. FIG. 8 is a diagram corresponding to FIG. 1 and is a diagram for explaining another modified example of the illumination device, the projection device, and the projection type video display device. FIG. 9 is a diagram showing still another modification of the lighting device. FIG. 10 is a view corresponding to FIG. 6, and is a perspective view for explaining still another modified example of the lighting device and its operation.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 10 are diagrams for explaining an embodiment of the present invention and a modification thereof, and are diagrams for explaining an illumination device, a projection device, and a projection type video display device. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

[Device configuration]
First, the configuration of a projection-type image display device that includes an illumination device that projects coherent light and a projection device and can make speckles inconspicuous will be described.

  A projection video display device 10 shown in FIG. 1 includes a screen 15 and a projection device 20 that projects video light including coherent light. The projection device 20 includes an illuminating device 40 that illuminates the illuminated region LZ located on the virtual plane with coherent light, and a spatial light modulator that is disposed at a position overlapping the illuminated region LZ and that is illuminated with the coherent light by the illuminating device 40. 30 and a projection optical system 25 that projects the coherent light from the spatial light modulator 30 onto the screen 15.

  As the spatial light modulator 30, for example, a transmissive liquid crystal microdisplay can be used. In this case, the spatial light modulator 30 illuminated in a planar shape by the illumination device 40 selects and transmits coherent light for each pixel, thereby forming a modulated image on the screen of the display that forms the spatial light modulator 30. Will come to be. The image light forming the modulated image thus obtained is projected onto the screen 15 by the projection optical system 25 at the same magnification or scaled. As a result, the modulated image is displayed on the screen 15 at the same magnification or variable magnification, that is, usually enlarged and displayed, and the observer can observe the image.

  As the spatial light modulator 30, a reflective micro display can be used. In this case, a modulated image is formed by the reflected light from the spatial light modulator 30, the surface on which the spatial light modulator 30 is irradiated with coherent light from the illumination device 40, and the image light that forms the modulated image from the spatial light modulator 30. The surface where the lead is the same surface. When such reflected light is used, a MEMS element such as a DMD (Digital Micromirror Device) can be used as the spatial light modulator 30. In the apparatus disclosed in JP6-208089A described above, DMD is used as a spatial light modulator.

  Moreover, it is preferable that the incident surface of the spatial light modulator 30 has the same shape and size as the illuminated region LZ irradiated with the coherent light by the illumination device 40. In this case, it is because the coherent light from the illuminating device 40 can be used with high utilization efficiency for displaying the image on the screen 15.

  The screen 15 may be configured as a transmissive screen or may be configured as a reflective screen. In the case where the screen 15 is configured as a reflective screen, the observer observes an image displayed by coherent light reflected by the screen 15 from the same side as the projection device 20 with respect to the screen 15. On the other hand, when the screen 15 is configured as a transmissive screen, the observer observes an image displayed by coherent light transmitted through the screen 15 from the side opposite to the projection device 20 with respect to the screen 15. .

  By the way, the coherent light projected on the screen 15 via the spatial light modulator 30 is diffused and recognized as an image by the observer. At this time, the coherent light projected on the screen interferes by diffusion and causes speckle. In addition, speckles can also be caused by factors such as diffusion in the spatial light modulator 30 and diffusion in the space, and these speckles can be visually recognized by being projected on the screen 15. become. However, in the projection display apparatus 10 described here, the illumination apparatus 40 described below illuminates the illuminated area LZ on which the spatial light modulator 30 is superimposed with coherent light that changes in angle with time. It is like that. More specifically, the illumination device 40 described below illuminates the illuminated area LZ with coherent light. At this time, the incident angle of light incident on each position of the illuminated area LZ changes with time. To go. As a result, the diffusion pattern of the coherent light on the screen 15 also changes with time, and speckles generated by the diffusion of the coherent light are temporally superimposed and become inconspicuous. Hereinafter, such an illuminating device 40 will be described in more detail.

  The illuminating device 40 shown in FIG. 1 optically transmits an optical element 50 including a plurality of light diffusing elements 55a, 55b, and 55c arranged at different positions and a plurality of coherent lights La, Lb, and Lc having different wavelength ranges. It has the irradiation apparatus 60 which irradiates the element 50, the synthesizing | combining apparatus 70 which synthesize | combines the light from each light-diffusion element 55, and the integrator rod 80 connected to the synthesizing | combining apparatus. The coherent lights La, Lb, and Lc synthesized by the synthesizer 70 and then uniformized by the integrator rod 80 proceed from the exit surface 80b of the integrator rod 80 as illumination light that illuminates the illuminated region LZ.

  In the illustrated example, the irradiation device 60 includes the first coherent light La in the first wavelength range, the second coherent light Lb in the second wavelength range different from the first wavelength range, the first wavelength range, and the second wavelength. The third coherent light Lc in the third wavelength region different from any of the regions is projected. On the other hand, the optical element 50 includes first to third light diffusing elements 55a, 55b, and 55c corresponding to the first to third coherents La, Lb, and Lc, respectively. The irradiation device 60 scans the first coherent light La in the first wavelength region on the first light diffusing element 55a, scans the second coherent light Lb in the second wavelength region on the second light diffusing element 55b, and The optical elements 50 are irradiated with coherent light La, Lb, and Lc having different wavelength regions so that the third coherent light Lc in the third wavelength region scans on the third light diffusing element 55c. The combining device 70 includes a first coherent light La from the first light diffusing element 55a, a second coherent light Lb from the second light diffusing element 55b, a third coherent light Lc from the third light diffusing element 55c, Is synthesized.

  That is, the first coherent light La projected from the irradiation device 60 is diffused by the first light diffusing element 55a of the optical element 50, and enters the synthesis device 70 through the first incident surface 70a1. The second coherent light Lb in the second wavelength region projected from the irradiation device 60 is diffused by the second light diffusing element 55b of the optical element 50 and is incident on the synthesizing device 70 via the second incident surface 70a2. Further, the third coherent light Lc in the third wavelength region projected from the irradiation device 60 is diffused by the third light diffusing element 55c of the optical element 50, and enters the synthesizing device 70 via the third incident surface 70a3.

  The exit surface 70 b of the synthesizer 70 is connected to the entrance surface 80 a of the integrator rod 80. Therefore, the first coherent light La, the second coherent light Lb, and the third coherent light Lc synthesized by the synthesizing device 70 enter the integrator rod 80. Then, the first coherent light La, the second coherent light Lb, and the third coherent light Lc emitted from the emission surface 80b of the integrator rod 80 illuminate the illuminated region LZ. In the illustrated example, the first to third coherent lights La, Lb, and Lc from the illumination device 40 illuminate the spatial light modulator 30 that is disposed so as to overlap the illuminated area LZ.

  The light diffusing elements 55a, 55b, and 55c of the optical element 50 are elements having a function of diffusing or expanding coherent light from the irradiation device 60. For example, the light diffusing elements 55a, 55b, and 55c may be formed of a hologram recording medium. Various known holographic optical elements can be used as the hologram recording medium used for the light diffusing elements 55a, 55b, and 55c. As a specific example, the light diffusing elements 55a, 55b, and 55c can be formed of a transmission type volume hologram or a relief type computer-generated hologram.

  A transmission type volume hologram or a relief type computer-generated hologram has a feature that its wavelength selectivity is lower than that of a reflection type volume hologram. Therefore, a plurality of transmission-type volume holograms and relief-type computer-generated holograms intended to exert a predetermined diffraction action on light in different wavelength ranges are generally not used in a stacked manner. As in the embodiment described here, they are arranged so as to be spatially shifted so that only light in the design wavelength region can enter. That is, the form described here, specifically, the form in which light in a plurality of wavelength regions is diffused by a light diffusing element that is a separate hologram recording medium and then combined to form illumination light is a transmission type. It can be said that the volume hologram and the relief-type computer-generated hologram are suitable for use as a light diffusing element.

  In the following, the light diffusing elements 55a, 55b, and 55c are configured as a holographic recording medium that can reproduce the transmission type volume hologram that diffuses or spreads the coherent light La, Lb, and Lc, in particular, the image 5 of the scattering plate 6. Take examples as appropriate. However, as can be understood from the above description, the light diffusing elements 55a, 55b, and 55c are not limited to transmission type volume holograms, and relief-type computer-generated holograms are used as the light diffusing elements 55a, 55b, and 55c. Further, various optical elements such as a reflection type volume hologram and a lens array may be used as the light diffusing elements 55a, 55b, and 55c.

  In the illustrated example, the light diffusing elements 55a, 55b, and 55c included in the optical element 50 receive the coherent light La, Lb, and Lc irradiated from the irradiation device 60 and incident on the respective positions as reproduction illumination light, and the coherent light. The light La, Lb, and Lc can be diffracted with high efficiency. That is, the light diffusing elements 55a, 55b, and 55c diffract and spread the coherent light incident on each position, in other words, each minute region that should be called each point, and corresponding incident surfaces 70a1, 70a2 of the synthesizer 70. , 70a3. In particular, in the example shown in FIGS. 2 to 4, the light diffusing elements 55 a, 55 b, and 55 c diffract coherent light incident on each position, in other words, each minute region that should be called each point, The image 5 of the scattering plate 6 can be reproduced.

  On the other hand, as described above, the irradiation device 60 irradiates the optical element 50 with coherent light so that the coherent light La, Lb, and Lc scans the light diffusion elements 55a, 55b, and 55c of the optical element 50. Accordingly, the regions on the light diffusion elements 55a, 55b, and 55c irradiated with the coherent light La, Lb, and Lc by the irradiation device 60 at a certain moment are part of the surface of the light diffusion elements 55a, 55b, and 55c. In particular, in the illustrated example, the region is a minute region to be called a point. That is, at a certain moment, the light diffusing elements 55a, 55b, and 55c diffuse the coherent light La, Lb, and Lc incident on a part of the surface thereof, thereby corresponding incident surfaces 70a1, 70a2, and the corresponding incident surfaces 70a1, 70a2, and the like of the synthesizer 70. Irradiate to 70a3. In other words, at a certain moment, the light diffusing elements 55a, 55b, and 55c diffuse the coherent light La, Lb, and Lc incident on a part of the surface of the light diffusing elements in a certain angle range rather than having a constant traveling direction. The light or divergent light beam is shaped and made incident on the incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70.

  Then, the coherent light La, Lb, Lc irradiated from the irradiation device 60 and scanned on the light diffusing elements 55a, 55b, 55c is positioned on the light diffusing elements 55a, 55b, 55c. , The same)) is incident at an incident angle that satisfies the diffraction conditions of the light diffusing elements 55a, 55b, and 55c. As shown in FIGS. 2 to 4, the coherent lights La, Lb, and Lc that have entered the light diffusing elements 55 a, 55 b, and 55 c from the irradiation device 60 are light diffusing elements 55 a, 55 b, and 55 c, respectively. Diffracted to illuminate at least a portion of the corresponding entrance surfaces 70a1, 70a2, 70a3 of the synthesizer 70. That is, the coherent light La, Lb, Lc incident on each position of the light diffusion elements 55a, 55b, 55c from the irradiation device 60 is enlarged and irradiated to at least a part of the corresponding incident surfaces 70a1, 70a2, 70a3 of the synthesis device 70. Is done.

  In the example shown in FIGS. 2 to 4, the coherent lights La, Lb, and Lc incident on the light diffusion elements 55 a, 55 b, and 55 c from the irradiation device 60 are diffracted by the light diffusion elements 55 a, 55 b, and 55 c. The regions IAa, IAb, and IAc on the incident surfaces 70a1, 70a2, and 70a3 of the synthesizing device 70 that are incident after being overlapped at least partially. As described above, when the light diffusing elements 55a, 55b, and 55c are formed as transmission-type volume holograms that can reproduce the image 5 of the scattering plate 6, the light diffusing elements 55a, 55b, and 55c are irradiated from the irradiation device 60. The coherent light La, Lb, Lc incident on each position can reproduce the image 5 of the scattering plate 6 so as to overlap at least partially on the corresponding incident surfaces 70a1, 70a2, 70a3 of the synthesizer 70. Become.

  In particular, in the example shown in FIGS. 2 and 4, the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55a, 55b, 55c travels by the light diffusing elements 55a, 55b, 55c, respectively. The direction is changed and the light is incident on the same region on the incident surfaces 70a1, 70a2 and 70a3 of the synthesizer 70. That is, the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55a, 55b, 55c from the irradiation device 60 is expanded to specific areas in the corresponding incident surfaces 70a1, 70a2, 70a3 of the synthesizer 70. Is irradiated. As described above, when the light diffusing elements 55a, 55b, and 55c are formed as transmission-type volume holograms that can reproduce the image 5 of the scattering plate 6, the light diffusing elements 55a, 55b, and 55c are irradiated from the irradiation device 60. The coherent light La, Lb, Lc incident on each position can be superimposed on the same area on the corresponding incident surfaces 70a1, 70a2, 70a3 of the synthesizer 70 to reproduce the image 5 of the scattering plate 6.

  In addition, in FIG. 2, the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55 a, 55 b, 55 c is changed in traveling direction by the light diffusing elements 55 a, 55 b, 55 c, respectively. Thus, the light is incident on the entire area of the combining device 70 which becomes the incident surfaces 70a1, 70a2, and 70a3. As described above, when the light diffusing elements 55a, 55b, and 55c are formed as transmission-type volume holograms that can reproduce the image 5 of the scattering plate 6, the light diffusing elements 55a, 55b, and 55c are irradiated from the irradiation device 60. The coherent light La, Lb, and Lc incident on each position can be superimposed on the regions that become the corresponding incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70 to reproduce the image 5 of the scattering plate 6.

  Each of the coherent lights La, Lb, and Lc is incident on the incident surface 80a of the integrator rod 80 via the synthesizer 70. Then, the light diffusing elements 55a, 55b, and 55c shape the coherent light La, Lb, and Lc incident on the respective positions of the light diffusing elements 55a, 55b, and 55c into diffused light or divergent light that spreads in an angular range. If so, the diffused light or divergent light effectively exhibits the uniformizing function of the integrator rod 80. Therefore, even if the coherent lights La, Lb, and Lc from the light diffusion elements 55a, 55b, and 55c are incident on only a part of the regions on the corresponding incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70, this is also possible. Accordingly, even if only a part of the region on the incident surface 80a of the integrator rod 80 is incident, the distribution of coherent light La, Lb, effectively uniformized from the entire region of the output surface 80b of the integrator rod 80 is achieved. Lc can be emitted. Therefore, the present invention is not limited to the examples shown in FIGS. 2 to 4, and for example, there may be no region where all of the incident regions IAa, IAb, and IAc in FIGS. 2 to 4 overlap.

  As the light diffusing elements 55a, 55b, and 55c capable of exhibiting the above diffraction function with respect to the coherent light La, Lb, and Lc, a transmission type volume hologram using a photopolymer can be used. For example, the light diffusing elements 55a, 55b, and 55c shown in FIG. 2 can be manufactured using the scattered light from the actual scattering plate 6 as the object light Lo as shown in FIG. In FIG. 5, reference light Lr and object light Lo made of coherent light having coherence with each other are exposed to the photosensitive hologram photosensitive material 58 that forms the light diffusion elements 55a, 55b, and 55c. The state is shown.

  For example, laser light from a laser light source that oscillates laser light in a specific wavelength region is used as the reference light Lr, and the reference light Lr travels along a certain direction as a parallel light flux and enters the hologram photosensitive material 58. As a specific example, laser light as a straight beam emitted from a laser light source is first diverged (spread) by a spatial filter or the like to be converted into a divergent light beam, and then a predetermined beam using a collimator. The light is converted into a parallel light beam having a cross-sectional area and then incident on the hologram photosensitive material 58.

  Next, the object light Lo is incident on the hologram photosensitive material 58 as scattered light from a scattering plate 6 made of, for example, opal glass. Here, since the light diffusing elements 55a, 55b, and 55c to be manufactured are transmissive types, the object light Lo enters the hologram photosensitive material 58 from the same side as the reference light Lr. The object light Lo needs to have coherency with the reference light Lr. Therefore, for example, laser light oscillated from the same laser light source can be divided, and one of the divided lights can be used as the reference light Lr and the other can be used as the object light Lo.

  In the example shown in FIG. 5, a parallel light beam parallel to the normal direction to the plate surface of the scattering plate 6 is incident on the scattering plate 6 and scattered, and the scattered light transmitted through the scattering plate 6 is the object light Lo. The light enters the hologram photosensitive material 58. According to this method, when an isotropic scattering plate that is usually available at a low cost is used as the scattering plate 6, the object light Lo from the scattering plate 6 is incident on the entire area of the hologram photosensitive material 58 with a substantially uniform light amount distribution. It becomes possible to do. Further, according to this method, although depending on the degree of scattering by the scattering plate 6, the reference light Lr is incident on each position of the hologram photosensitive material 58 with a substantially uniform light amount from the entire area of the exit surface 6 a of the scattering plate 6. It becomes easy. In such a case, the light incident on each position of the obtained light diffusing elements 55a, 55b, and 55c reproduces the image 5 of the scattering plate 6 with the same brightness. It can be realized that the image 5 of the scattering plate 6 is observed with substantially uniform brightness.

  As described above, when the hologram recording material 58 is exposed to the reference light Lr and the object light Lo, an interference fringe formed by the interference of the reference light Lr and the object light Lo is generated. In the case of a pattern, that is, a volume hologram, for example, it is recorded on the hologram recording material 58 as a refractive index modulation pattern. Thereafter, appropriate post-processing corresponding to the type of the hologram recording material 58 is performed, and the light diffusion elements 55a, 55b, and 55c are obtained.

  The light diffusing elements 55a, 55b, and 55c obtained through the exposure process of FIG. 5 can exhibit the reproducing function that is the diffraction function shown in FIG. As shown in FIG. 2, the light diffusing elements 55a, 55b, and 55c formed from the hologram photosensitive material 58 of FIG. 5 are light having the same wavelength as the laser light used in the exposure process, and are reference light in the exposure process. The Bragg condition is satisfied by the light traveling in the opposite direction on the optical path of Lr. That is, as shown in FIG. 2, the parallel light beam traveling in the opposite direction along the same direction as the traveling direction of the reference light Lr as the parallel light beam with respect to the light diffusing elements 55a, 55b, 55c The light is diffracted with high efficiency by the light diffusing elements 55a, 55b, and 55c arranged at the same position as the photosensitive material 58. The reproduction light diffracted by the light diffusing elements 55a, 55b, and 55c has the same positional relationship as the relative position of the scattering plate 6 with respect to the hologram photosensitive material 58 (see FIG. 5) in the exposure process. , 55b, 55c, the reproduced image 5 of the scattering plate 6 is generated at specific positions.

  At this time, the reproduction light for generating the reproduced image 5 of the scattering plate 6, that is, the diffracted light obtained by diffracting the reproduction illumination light by the light diffusing elements 55a, 55b, and 55c is transferred from the scattering plate 6 to the hologram photosensitive material 58 during the exposure process. Each point of the image 5 of the scattering plate 6 is reproduced as light traveling in the opposite direction along the optical path of the object light Lo that has traveled toward. As described above and as shown in FIG. 5, the scattered light Lo emitted from each position on the exit surface 6 a of the scattering plate 6 in the exposure process is incident on almost the entire region of the hologram photosensitive material 58. Is spreading (spreading). That is, the object light Lo from the entire region of the exit surface 6a of the scattering plate 6 enters each position on the hologram photosensitive material 58. As a result, information on the entire exit surface 6a is converted into the light diffusion elements 55a, 55b, and 55c. Is recorded at each position. For this reason, each light that forms a parallel light beam functioning as reproduction illumination light shown in FIG. 2 is incident on each position of the light diffusion elements 55a, 55b, and 55c and has the same contour. Images 5 of the scattering plate 6 can be reproduced at the same position.

  On the other hand, the irradiation device 60 that irradiates the optical element 50 including the light diffusing elements 55a, 55b, and 55c that satisfies the Bragg condition by the parallel light flux illustrated in FIG. 2 with the coherent light La, Lb, and Lc, Coherent light La, Lb, Lc traveling in a certain direction is irradiated to each position of the light diffusion elements 55a, 55b, 55c of the optical element 50. In other words, the irradiation device 60 irradiates each position of the light diffusing elements 55a, 55b, and 55c of the optical element 50 with coherent light along the optical path of one light beam forming a virtual parallel light beam.

  As a specific configuration, in the example illustrated in FIG. 1, the irradiation device 60 includes a light source mechanism 61 that generates a combined light SL formed by combining a plurality of coherent lights La, Lb, and Lc having different wavelength ranges, and a light source. A scanning device 65 that periodically changes the traveling direction of the combined light SL from the mechanism 61; and a separation device 69 that separates the combined light SL from the scanning device 65 into a plurality of coherent lights having different wavelength ranges. Yes.

  The light source mechanism 61 includes a plurality of light sources 61a, 61b, and 61c that respectively oscillate coherent light in a wavelength region corresponding to each of the coherent wavelength regions, and a combining unit 62 that combines the coherent light from the plurality of light sources 61a, 61b, and 61c. And a synthesis device. The light source mechanism 61 includes, as a plurality of light sources, a first light source 61a that oscillates the first coherent light La in the first wavelength region, a second light source 61b that oscillates the second coherent light Lb in the second wavelength region, And a third light source 61c that oscillates the third coherent light Lc in the three wavelength regions. For example, the first wavelength region corresponds to a first primary color component (for example, a red component), the second wavelength region corresponds to a second primary color component (for example, a green component), and the third wavelength region corresponds to a first wavelength region. You may make it respond | correspond to three primary color components (for example, blue component). According to this example, the irradiation device 60 can irradiate white light by additive color mixing of the first to third primary color components. On the other hand, as the synthesizing means 62, various members, parts, devices, etc. that synthesize two or more lights can be used. In the illustrated example, a half mirror having the advantage of being relatively inexpensive and small is used.

  The scanning device 65 changes the optical path of the coherent light La, Lb, Lc with time, and as a result, the coherent light La, Lb, Lc scans the corresponding light diffusion elements 55a, 55b, 55c. Thus, the light enters the optical element 50. In the example shown in FIGS. 1 and 6, the irradiation device 60 includes a reflection device 66 that has a reflection surface 66 a that reflects coherent light and is rotatable about at least one axis RA. A deflecting element 67 that deflects the optical path of the light reflected by the reflecting device 66 in a direction parallel to a certain direction ds.

  In the illustrated embodiment, the reflecting device 66 is configured as a mirror device having a mirror as a reflecting surface 66a that can be rotated about one axis RA1. As shown in FIG. 1 and FIG. 6, this mirror device 66 changes the orientation of the mirror 66a, and the combined light SL formed by synthesizing the coherent light La, Lb, Lc from the light source mechanism 61 is advanced. The direction is changed. At this time, as shown in FIG. 1, the mirror device 66 receives the coherent light La, Lb, and Lc from the light source mechanism 61 at a certain position (reference position) SP. For this reason, the coherent light La, Lb, and Lc is changed in the traveling direction by the mirror device 66 that periodically rotates within a predetermined angle range, and then enters the optical path of a light beam that forms a divergent light beam that diverges from the reference position SP. Along the way.

  On the other hand, the deflecting element 67 is configured to collimate the divergent light beam that diverges from the reference position SP and convert it into a parallel light beam, corresponding to the configuration of the reflection device 66 described above. Specifically, the deflection element 67 is configured as a lens and is disposed at a position where a divergent light beam diverging from the reference position SP can be collimated. For this reason, the coherent lights La, Lb, and Lc whose optical paths are adjusted by the deflecting element 67 are incident on the separating device 69 as light beams forming one light beam of parallel light beams.

  As the separation device 69, various members, components, devices, and the like that can separate light in two or more wavelength ranges can be used. In the illustrated example, a first separation mirror device 69a, a second separation mirror device 69b, and a third separation mirror device 69c, each of which is composed of a mirror device having wavelength selectivity, which have the advantages of being relatively inexpensive and small in size. Is used. In the example of FIG. 1, the separation mirror devices 69 a, 69 b, and 69 c are arranged along the traveling direction ds of the coherent light La, Lb, and Lc deflected by the scanning device 65 and the light deflected by the scanning device 65. It is arranged on the optical path.

  The third separation mirror device 69c is disposed at a position closest to the scanning device 65, and reflects the third coherent light Lc in the third wavelength region and transmits light in the other wavelength regions. The second separation mirror device 69b is disposed on the back surface of the third separation mirror device 69c, and reflects the second coherent light Lb in the second wavelength region and transmits light in the other wavelength regions. The first separation mirror device 69a is disposed on the back surface of the second separation mirror device 69b. The first separation mirror device 69a may be configured to reflect the first coherent light La in the first wavelength region and transmit light in other wavelength regions, or in the form described here. The mirror device may be configured as a normal mirror device that reflects light in all wavelength regions.

  The respective coherent lights La, Lb, and Lc reflected by the corresponding separation mirror devices 69a, 69b, and 69c enter the corresponding light diffusion elements 55a, 55b, and 55c. Since the reflection surfaces of the separation mirror devices 69a, 69b, and 69c are formed as flat surfaces, the coherent lights La, Lb, and Lc whose optical paths are finally adjusted by the separation mirror devices 69a, 69b, and 69c are one of the parallel light beams. It can be incident on the corresponding light diffusing elements 55a, 55b, and 55c of the optical element 50 as reproduced illumination light that forms a light beam. As a result, the coherent light from the irradiation device 60 scans on the light diffusing elements 55a, 55b, and 55c, and according to the light diffusing elements 55a, 55b, and 55c shown in FIG. The coherent lights La, Lb, and Lc incident on the light beam are superimposed on the same position, for example, the incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70, or each incident surface It can be reproduced by being superimposed on a position inside the synthesizing apparatus 70 via 70a1, 70a2 and 70a3. In these examples, the coherent lights La, Lb, and Lc from the light diffusing elements 55a, 55b, and 55c can all enter the synthesizer 70, and the utilization efficiency of the coherent lights La, Lb, and Lc is considered. To preferred.

  FIG. 6 shows a perspective view of the configuration of the irradiation device 60 and the optical element 50 shown in FIG. However, the separation mirror devices 69a, 69b, and 69c of the separation device 69 included in the irradiation device 60 are different from each other in the wavelength range to be reflected and can be configured identically to each other. Only the device is shown. Similarly, the light diffusing elements 55a, 55b, and 55c of the optical element 50 are different from each other in the wavelength range of the coherent light La, Lb, and Lc intended to be diffracted, and can be configured to be the same as each other. FIG. 6 shows only one light diffusing element.

  The reflection device 66 shown in FIG. 6 is configured to rotate the mirror 66a along one axis RA1. For this reason, the incident point IP1 of the coherent light whose traveling direction is continuously changed by the reflection device 66 to the deflection element 67 reciprocates along the linear scanning path PW1 on the incident surface of the lens forming the reflection device 66. become. In particular, in the example shown in FIG. 6, the rotation axis RA1 of the reflection device 66 has an XY coordinate system defined on the plate surfaces of the light diffusion elements 55a, 55b, and 55c, that is, the XY plane is the light diffusion element 55a, It extends parallel to the Y axis of the XY coordinate system which is parallel to the plate surfaces 55b and 55c. Then, the reflecting surface 66a periodically rotates about an axis line RA1 parallel to the Y axis of the XY coordinate system defined on the plate surfaces of the light diffusing elements 55a, 55b, and 55c. The incident point IP2 of the coherent light La, Lb, Lc to the optical element 50 reciprocates in a direction parallel to the X axis of the XY coordinate system defined on the plate surfaces of the light diffusion elements 55a, 55b, 55c. become. That is, in the example shown in FIG. 6, the irradiation device 60 irradiates the optical element 50 with the coherent light so that the coherent light scans the light diffusion elements 55a, 55b, and 55c along the straight path PW2.

  In the example shown in FIG. 1, the separation mirror devices 69 a, 69 b, and 69 c are arranged along the direction ds deflected by the scanning device 65 and arranged on the optical path of the light deflected by the scanning device 65. Has been. On the other hand, the light diffusion elements 55a, 55b, and 55c of the optical element 50 are arranged side by side along the arrangement direction ds of the separation mirror devices 69a, 69b, and 69c corresponding to the separation mirror devices 69a, 69b, and 69c. Yes. As shown in FIG. 1, the light diffusing elements 55a, 55b, and 55c are arranged on one plane. According to such a form, the light diffusing elements 55a, 55b, and 55c can be formed, arranged, or bonded on the same base material, the configuration is simplified, and the apparatus can be downsized. It becomes.

  The wavelengths of the coherent lights La, Lb, and Lc incident on the light diffusing elements 55a, 55b, and 55c of the optical element 50 need to be exactly matched to the wavelengths of light used in the recording process, which is the exposure process in FIG. No, the image 5 can be substantially reproduced in a predetermined region even if it is slightly deviated from the wavelength of light used in the exposure process. In the first place, as a practical problem, when the light diffusing elements 55a, 55b, and 55c are formed, the hologram recording material 58 may shrink. In such a case, the shrinkage of the hologram recording material 58 is considered. Thus, it is preferable that the wavelengths of the coherent light La, Lb, and Lc irradiated from the irradiation device 60 to the optical element 50 are adjusted. From such a point, the wavelength of the coherent light generated by the coherent light sources 61a, 61b, and 61c of the light source mechanism 61 does not need to exactly match the wavelength of the light used in the recording process, which is the exposure process in FIG. It is sufficient that they are almost the same.

  For the same reason, the traveling direction of the light incident on each position of the light diffusing elements 55a, 55b, and 55c of the optical element 50 is not limited to the path along the same direction. 5 can be substantially reproduced. Actually, in the example shown in FIGS. 1 and 6, the mirror (reflective surface) 66a of the reflective device 66 is inevitably deviated from the rotation axis RA1. Therefore, when the mirror 66a is rotated about the rotation axis RA1 that does not pass through the reference position SP, the coherent light traveling from the reflection device 66 to the deflecting element 67 is divergent from the reference position SP in a strict sense. As a result, the coherent light traveling from the scanning device 65 toward the optical element 50 may not always travel in the same constant direction ds in a strict sense. In practice, however, the coherent light La, Lb, and Lc incident on the light diffusion elements 55a, 55b, and 55c constituting the optical element 50 from the irradiation device 60 having the illustrated configuration are substantially scheduled. The image 5 can be reproduced overlaid on the area.

  From these points, terms that specify the geometric conditions such as “same direction”, “constant direction”, “parallel” and the like used in this specification are not limited to strict meanings, but have similar optical functions. Is to be interpreted including an error that can be expected.

  The synthesizing device 70 can be configured using various members, parts, devices, and the like that synthesize two or more lights. In the example shown in FIG. 1, the synthesizing device 70 has synthesizing means 71 that can be constituted by, for example, a dichroic prism. In the example shown in FIG. 1, the synthesizing means 71 is disposed so as to face the second light diffusing element 55b. The portion of the combining means 71 that faces the second light diffusing element 55b forms a second incident surface 70a2 that receives the second coherent light Lb from the second light diffusing element 55b. The synthesizing device 70 is arranged opposite to the first light diffusing element 55a and is arranged opposite to the first guiding means 72a connected to the synthesizing means 71 and the third light diffusing element 55c. Second guiding means 72b connected to the means 71.

  A portion of the first guiding means 72a facing the first light diffusing element 55a forms a first incident surface 70a1 that receives the first coherent light La from the first light diffusing element 55a. The first guiding unit 72 a includes a prism, a mirror, and the like, and guides the first coherent light La from the first light diffusing element 55 a to the combining unit 71. The portion of the second guiding means 72b facing the third light diffusing element 55c forms a third incident surface 70a3 that receives the third coherent light Lc from the third light diffusing element 55c. The second guiding unit 72 b includes a prism, a mirror, and the like, and guides the third coherent light Lc from the third light diffusing element 55 c to the combining unit 71.

  The combining unit 71 then includes the first coherent light La from the first light diffusing element 55a, the second coherent light Lb from the second light diffusing element 55b, and the third coherent light Lc from the third light diffusing element 55c. And are guided to the integrator rod 80 via the emission surface 70b.

  In the example of FIG. 1, in response to the light diffusing elements 55a, 55b, and 55c being arranged side by side on one plane, the combining apparatus 70 has its incident surfaces 70a1, 70a2, and 70a3 positioned on one plane. So that they are arranged. In particular, the virtual surface on which the incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70 are arranged is parallel to the virtual surface on which the light diffusion elements 55a, 55b, and 55c are arranged, and an integrator rod 80 described later. It is orthogonal to the longitudinal direction.

  Note that the synthesizer 70 exemplified here adjusts the optical path without shaping the overall distribution of the coherent light La, Lb, and Lc from the light diffusing elements 55a, 55b, and 55c, or performs regular reflection or the like. The optical path is adjusted and merged while restricting the spread to the side, and guided to the integrator rod 80. Therefore, the coherent lights La, Lb, and Lc emitted from the light diffusing elements 55a, 55b, and 55c are synthesized by proceeding with predetermined optical path lengths determined depending on the configuration of the synthesizer 70, and then the synthesizer It goes to the integrator rod 80 through the 70 exit surface 70b.

  Next, the integrator rod 80 will be described. The incident surface 80 a of the integrator rod 80 is connected to the emission surface 70 b of the synthesizer 70 and receives the first to third coherent lights La, Lb, and Lc from the synthesizer 70. The coherent lights La, Lb, and Lc incident on the integrator rod 80 are emitted from the illumination device 40 via the emission surface 80b of the integrator rod 80, and are directed to the illuminated region LZ as illumination light.

  The integrator rod 80 has a function of making the light distribution uniform by repeatedly causing total reflection of incident light. Therefore, the in-plane variation of the illuminance distribution on the exit surface 80 b of the integrator rod 80 is smaller than the in-plane variation of the light amount distribution on the incident surface 80 a of the integrator rod 80. Further, as already mentioned, if the integrator rod 80 exhibits a sufficiently uniform function, the coherent light La, Lb, Lc is only incident on a part of the incident surface 80a of the integrator rod 80. In addition, the coherent light La, Lb, and Lc is emitted from the entire emission surface 80 b of the integrator rod 80.

  By the way, in order to illuminate the illuminated area LZ with a plurality of coherent lights La, Lb, and Lc having different wavelength ranges, the coherent lights La, Lb, and Lc illuminates a region on the illuminated region LZ that overlaps at least in part, and the at least a portion on the illuminated region LZ that is illuminated so as to overlap by each coherent light La, Lb, Lc has a different wavelength. What is necessary is just to make it overlap at least partially between the coherent light La, Lb, and Lc of the area. In this case, a region where the coherent light La, Lb, Lc in each wavelength region is always illuminated is present on the illuminated region LZ regardless of the state of the scanning device 65, and the coherent light La, Lb in each wavelength region is present. , Lc are illuminated at least partially on the illuminated area LZ between the coherent lights La, Lb, Lc in different wavelength ranges. That is, there is a region in the illuminated region LZ where the coherent light La, Lb, and Lc in all wavelength regions is continuously illuminated, and as an example, a region in which white light synthesized from the three primary color components of light is continuously illuminated. It will be different. Such illumination includes the optical path length from each of the entrance surfaces 70a1, 70a2, 70a to the exit surface 70b of the synthesizer 70, the uniformizing function by the integrator rod 80, and the exit surfaces 81b, 82b, 83b of the integrator rod 80. In consideration of the optical path length to the irradiation surface LZ, by adjusting the distribution of diffracted light from the light diffusion elements 55a, 55b, 55c, for example, the incident angles on the respective incident surfaces 70a1, 70a2, 70a3 of the synthesizer 70. Can be realized.

  On the other hand, considering the projection device 20, as shown in FIG. 1, the spatial light modulator 30 is disposed so as to face the emission surface 80 b of the integrator rod 80. Then, the light from the integrator rod 80 illuminates the spatial light modulator 30 as illumination light by the illumination device 40.

In the projection device 20, in order to form an image by illuminating the spatial light modulator 30 with the three types of coherent light La, Lb, and Lc, a plurality of coherent lights La, Lb, and Lc having different wavelength ranges are used. What is necessary is just to satisfy | fill the conditions similar to the case where the illumination area | region LZ is illuminated. More specifically, it is preferable that the illumination device 40 is configured so that the following conditions (a) to (d) are satisfied.
(A) The first coherent light La incident on each position of the first light diffusing element 55a from the irradiation device 60 illuminates a region on the spatial light modulator 30 that overlaps at least partially after passing through the integrator rod 80. .
(B) The second coherent light Lb incident on each position of the second light diffusing element 55b from the irradiation device 60 passes through the integrator rod 80, and then illuminates a region on the spatial light modulator 30 that overlaps at least partially. .
(C) The third coherent light Lc incident on each position of the third light diffusing element 55c from the irradiation device 60 passes through the integrator rod 80 and then illuminates a region on the spatial light modulator 30 that overlaps at least partially. .
(D) the at least part on the spatial light modulator 30 illuminated so as to overlap with the first coherent light La, and the at least part on the spatial light modulator 30 illuminated so as to overlap with the second coherent light Lb. The at least part of the spatial light modulator 30 illuminated so as to overlap with the third coherent light Lc is at least partially overlapped.

  When the conditions (a) to (c) for the first to third coherent lights La, Lb, and Lc are satisfied, the coherent light is applied to at least some areas regardless of scanning with the irradiation device 60. La, Lb, and Lc continue to be illuminated. When the condition (d) is further satisfied, there is a region where the first to third coherent lights La, Lb, and Lc are constantly illuminated regardless of scanning with the irradiation device 60. Then, the spatial light modulator 30 is placed in a region where the first to third coherent lights La, Lb, and Lc are constantly illuminated, so that the spatial light modulator 30 is overlapped with the first to third coherent lights La. , Lb, Lc can be continuously illuminated. For example, it is possible to generate a full-color image using the spatial light modulator 30.

  As already mentioned, if the integrator rod 80 exhibits a sufficiently uniform function, even if the coherent light La, Lb, Lc is incident only on a part of the incident surface 80a of the integrator rod 80, Coherent light La, Lb, and Lc are emitted from the entire emission surface 80b of the integrator rod 80. In this case, the spatial light modulator 30 is arranged in the vicinity of the emission surface 70b of the synthesis device 70, so that the spatial light modulator 30 is independent of the emission direction of the coherent light La, Lb, Lc from the synthesis device 70. Can be illuminated with the first to third coherent lights La, Lb, and Lc.

[Effects of the device]
Next, the operation of the illumination device 40, the projection device 20, and the projection display device 10 having the above-described configuration will be described.

  First, the irradiation device 60 irradiates the optical element 50 with the coherent lights La, Lb, and Lc so that the coherent lights La, Lb, and Lc scan the light diffusion elements 55a, 55b, and 55c of the optical element 50. Specifically, the first to third coherent lights La, Lb, and Lc emitted from the first to third light sources 61a, 61b, and 61c are scanned as combined light SL that is combined by the combining unit 62. The light enters the reference point SP of the device 65. The traveling direction of the synthesized light SL is spatially changed by the scanning device 65. More specifically, the combined light SL periodically translates the optical path so as to follow the optical path of one ray of the virtual parallel light beam. Thereafter, the synthesized light SL is separated for each wavelength range by the separating means 69 and the traveling direction is changed toward the corresponding light diffusion elements 55a, 55b, and 55c. Each of the coherent lights La, Lb, and Lc is incident on the corresponding light diffusion elements 55a, 55b, and 55c while the traveling directions thereof are periodically translated. In this way, the coherent lights La, Lb, and Lc are incident on the light diffusing elements 55a, 55b, and 55c so as to scan the corresponding light diffusing elements 55a, 55b, and 55c.

  Further, when the coherent lights La, Lb, and Lc are incident on the corresponding positions of the light diffusing elements 55a, 55b, and 55c, the incident angles satisfying the Bragg condition at the corresponding positions of the corresponding light diffusing elements 55a, 55b, and 55c. Incident at. As a result, the coherent light incident on each position is diffracted by the light diffusing elements 55a, 55b, and 55c and shaped into diffused light that spreads over a certain angular range. Then, the coherent lights La, Lb, and Lc are incident on the synthesizer 70 through the corresponding incident surfaces 70a1, 70a2, and 70a3 as diffused light that spreads over a certain angle range.

  When the light diffusing elements 55a, 55b, and 55c produced by the method shown in FIG. 5 and exhibiting the diffraction characteristics shown in FIG. 2 are used, the light diffusing elements 55a, 55b, and 55c are incident on the respective positions. By diffracting the coherent light La, Lb, and Lc to be reproduced, the image 5 of the scattering plate 6 is reproduced on the corresponding incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70, respectively. That is, the coherent light La, Lb, and Lc incident on each position of the light diffusing elements 55a, 55b, and 55c from the irradiation device 60 is diffused or expanded by the optical element 50, respectively, and the corresponding incident surface 70a1 of the synthesizer 70 , 70a2 and 70a3. According to such a form, not only the utilization efficiency of the coherent light La, Lb, Lc can be improved without generating the coherent light La, Lb, Lc that cannot be used, but also the coherent light La, Lb, The angular range of the traveling direction of Lc can be changed to a wider range, and the in-plane distribution of the coherent light La, Lb, and Lc can be made more uniform. It can be made inconspicuous.

  Coherent light La, Lb, Lc from each of the light diffusing elements 55a, 55b, 55c is synthesized by the synthesizer 70 and guided to the integrator rod 80 connected to the emission surface 70b of the synthesizer 70.

  The illumination device 40 irradiates the optical element 50 with the coherent light La, Lb, and Lc so that the coherent light La, Lb, and Lc scans the light diffusion elements 55a, 55b, and 55c. That is, the incident positions of the coherent lights La, Lb, and Lc on the light diffusing elements 55a, 55b, and 55c always change. For this reason, the incident angles of the coherent lights La, Lb, and Lc incident on the respective positions of the incident surfaces 70a1, 70a2, and 70a3 of the combining device 70 continue to change. The synthesizing device 70 described here adjusts the optical path without shaping the overall distribution of the first to third coherent lights La, Lb, and Lc, or spreads to the side by regular reflection or the like. The light paths are adjusted and merged while being regulated, and guided to the incident surface 80 a of the integrator rod 80. Therefore, at each position of the incident surface 80a of the integrator rod 80, the incident angle of the coherent light La, Lb, Lc incident on the position, that is, the angle formed by the incident direction with respect to the longitudinal direction of the integrator rod 80 continues to change. .

  In particular, when the light diffusing elements 55a, 55b, and 55c exhibiting the diffusion characteristics shown in FIG. 2 are used, the coherent light La, Lb, Lc is incident. For this reason, the coherent light La, Lb, and Lc can be constantly incident on the entire incident surface 80a of the integrator rod 80. In this case, at each position of the incident surface 80a of the integrator rod 80, the incident angle of the coherent light La, Lb, Lc incident on the position continues to change continuously and periodically within a larger angle range.

  The integrator rod 80 has a function of making the in-plane distribution of the light quantity uniform by repeatedly causing total reflection of incident light. And the diffused light which spreads with the angle range projected from the light diffusing elements 55a, 55b and 55c is effectively exerted on the uniformizing action of the integrator rod 80. Therefore, the amount of emitted light at each position on the exit surface 80b of the integrator rod 80 is effectively equalized.

  The uniformizing function by the integrator rod 80 is caused by total reflection inside the integrator rod 80. Therefore, the traveling direction of the light beam emitted from the integrator rod 80 at a certain moment is determined depending on the traveling direction when the light beam is incident on the integrator rod 80. Assuming that the homogenization function by the integrator rod 80 is sufficiently exhibited, the maximum incident angle when the light beam is incident on the incident surface 80a of the integrator rod 80 is determined by the output of the integrator rod 80 from the integrator rod 80. The size of the maximum emission angle at the time of emission from the surface 80b is the same, and similarly, the size of the minimum incident angle at the time of incidence of the luminous flux on the incidence surface 80a of the integrator rod 80 is the emission surface of the integrator rod 80 of the luminous flux. This is the minimum emission angle at the time of emission from 80b.

  That is, the angle range in the emission direction of the coherent light La, Lb, and Lc emitted from the emission surface 80b of the integrator rod 80 depends on the angle range of the incident angle when the light enters the incidence surface 80a of the integrator rod 80. . Since the incident angles of the coherent light La, Lb, and Lc to the integrator rod 80 change with time, the angular range in the emission direction of the coherent light La, Lb, and Lc emitted from the output surface 80b of the integrator rod 80 is also determined. Will change. On the other hand, the angular range in the emission direction of the coherent light La, Lb, and Lc emitted from the emission surface 80b of the integrator rod 80 at an arbitrary moment is made uniform at each position in the emission surface 80b.

  Here, “incident angle at the time of incidence on the incident surface of the integrator rod” means that the traveling direction of incident light on the incident surface 80a of the integrator rod 80 is the longitudinal direction of the integrator rod 80, in other words, the integrator rod 80. It is an angle made with respect to the light guide direction. Similarly, “the exit angle at the time of exit from the exit surface of the integrator rod” means that the traveling direction of the exit light from the exit surface 80 b of the integrator rod 80 is the longitudinal direction of the integrator rod 80, in other words, the integrator rod 80. It is the angle made with respect to the light guide direction.

  As described above, the coherent light La, Lb, and Lc emitted from the emission surface 80 b of each integrator rod 80 illuminates the spatial light modulator 30 as illumination light from the illumination device 40. It should be noted that the coherent light La, Lb, Lc in each wavelength region is directed toward the spatial light modulator 30 with the light amount effectively uniformed from the entire area of the exit surface 80b of the integrator rod 80 by the homogenizing function of the integrator rod 80. Will be projected. As a result, the spatial light modulator 30 is illuminated over the entire area by the first coherent light La, the second coherent light Lb, and the third coherent light Lc that exhibit an effectively uniformed in-plane light quantity distribution. .

  The spatial light modulator 30 is illuminated on the surface by the illumination device 40 to form a modulated image. The modulated image formed by the spatial light modulator 30 is projected onto the screen 15 by the projection optical system 25. The coherent lights La, Lb, and Lc forming the modulated image projected on the screen 15 are diffused and recognized as an image by the observer.

  The illumination device 40 illuminates the spatial light modulator 30 with coherent light La, Lb, and Lc in a plurality of wavelength regions. When the spatial light modulator 30 includes, for example, a color filter and can form a modulated image for each coherent light in each wavelength band, it is possible to display an image in a plurality of colors. Alternatively, even if the spatial light modulator 30 does not include a color filter, the irradiation device 60 irradiates the coherent light of each wavelength region in a time-sharing manner, and the spatial light modulator 30 is irradiated with the wavelength region. Even when operating in a time-sharing manner so as to form a modulated image corresponding to the coherent light, it is possible to display an image in a plurality of colors. In particular, in the projection device 20 or the projection type image display device 10, the irradiation device 60 includes a coherent light in a wavelength region corresponding to red light, a coherent light in a wavelength region corresponding to green light, and a wavelength region corresponding to blue light. The coherent light can be displayed in full color.

  By the way, conventionally, when the coherent light La, Lb, and Lc forming an image is projected onto the screen 15, the coherent light La, Lb, and Lc is scattered on the screen 15, and this scattering causes interference, and speckles are generated. It has occurred.

  However, according to the lighting device 40 described here, speckles can be made extremely inconspicuous as described below.

  According to the above-mentioned document “Speckle Phenomena in Optics, Joseph W. Goodman, Roberts & Co., 2006”, in order to make speckles inconspicuous, parameters such as polarization, phase, angle, and time are multiplexed to increase the mode. It is said that it is effective. The mode here refers to speckle patterns that are uncorrelated with each other. For example, when coherent light is projected from different directions onto the same screen from a plurality of laser light sources, there are as many modes as the number of laser light sources. In addition, when coherent light from the same laser light source is projected onto the screen from different directions by dividing the time, the mode is the same as the number of times the incident direction of the coherent light has changed during the time that cannot be resolved by the human eye. Will exist. When there are a large number of these modes, the interference patterns of light are uncorrelated and averaged, and as a result, speckles observed by the observer's eyes are considered inconspicuous.

  In the irradiation device 60 described above, each of the coherent lights La, Lb, and Lc is irradiated onto the optical element 50 so as to scan the light diffusion elements 55a, 55b, and 55c. In addition, the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55a, 55b, 55c from the irradiation device 60 is diffracted and diffused as a diffused light spreading in a certain angle range. The light enters the corresponding incident surfaces 70 a 1, 70 a 2, 70 a 3 and is guided to the integrator rod 80. Incident angles of the coherent light La, Lb, and Lc to the integrator rod 80 change with time. For this reason, the emission directions of the coherent lights La, Lb, and Lc emitted from the integrator rod 80 with the light quantity distribution made uniform also change over time. As a result, the incident direction of the illumination light incident on the illuminated area LZ where the spatial light modulator 30 is disposed from the illumination device 40 also changes over time.

  Considering this point with respect to the illuminated area LZ, the coherent lights La, Lb, and Lc are constantly incident on the respective positions in the illuminated area LZ, but the incident direction is constantly changing. It will be. As a result, the light forming each pixel of the modulated image formed by the light transmitted through the spatial light modulator 30 changes its optical path over time as indicated by an arrow A in FIG. Projected.

  Each coherent light La, Lb, Lc continuously scans on the light diffusing elements 55a, 55b, 55c. Accordingly, the incident direction of coherent light from the illumination device 40 to the illuminated region LZ also changes continuously, and the incident direction of coherent light from the projection device 20 to the screen 15 also changes continuously. Here, the incident direction of the coherent light from the projection device 20 to the screen 15 is slightly, for example, 0. If it changes by a few degrees, the speckle pattern generated on the screen 15 also changes greatly, and an uncorrelated speckle pattern is sufficiently superimposed. In addition, the frequency of scanning devices 65 such as MEMS mirrors and polygon mirrors that are commercially available is usually several hundred Hz or higher, and scanning devices 65 that reach tens of thousands of Hz are not uncommon.

  From the above, according to the illumination device 40 described above, the incident direction of the coherent light changes temporally at each position on the screen 15 displaying the image, and this change is It is a speed that cannot be resolved by the eyes, and as a result, a non-correlated coherent light scattering pattern is multiplexed and observed by the human eye. Therefore, speckles generated corresponding to each scattering pattern are overlapped and averaged and observed by an observer. Thereby, speckles can be made very inconspicuous for an observer who observes the image displayed on the screen 15.

  Note that conventional speckles observed by humans include only speckles outside the apparatus due to factors outside the apparatus such as the illumination apparatus 40 and the projection apparatus 20 such as the scattering of coherent light on the screen 15. In addition, speckles on the apparatus side due to scattering of coherent light before being projected onto a screen or the like may also occur. The speckle pattern generated on the apparatus side is projected onto the screen 15 via the spatial light modulator 30 so that it can be recognized by the observer. However, according to the embodiment described above, coherent light continuously scans on the light diffusing elements 55a, 55b, and 55c, and the coherent light incident on each position of the light diffusing elements 55a, 55b, and 55c is It is incident on the synthesizer 70 and the integrator rod 80 as diffused light that spreads over a certain angular range. That is, the light diffusing elements 55a, 55b, and 55c form a new wavefront that is separate from the wavefront that had been used to form the speckle pattern. The screen 15 is illuminated via the modulator 30. The speckle pattern generated on the apparatus side is invisible due to the formation of a new wavefront in the light diffusing elements 55a, 55b, and 55c.

  By the way, in the above-mentioned document “Speckle Phenomena in Optics, Joseph W. Goodman, Roberts & Co., 2006”, a numerical value called speckle contrast (unit%) is used as a parameter indicating the degree of speckle generated on the screen. A method of using it has been proposed. This speckle contrast is defined as a value obtained by dividing the standard deviation of the actual luminance variation on the screen divided by the average luminance value when displaying a test pattern image that should have a uniform luminance distribution. Amount. The larger the speckle contrast value is, the larger the speckle occurrence level on the screen is, which indicates that the spot-like luminance unevenness pattern is more prominently presented to the observer.

  The speckle contrast was investigated for the projection-type image display device 10 of the basic form described with reference to FIG. 1 (Condition 1). Further, as the above-described optical element 50, an uneven shape designed by using a computer so that the image 5 of the scattering plate 6 can be reproduced when receiving specific reproduction illumination light instead of the transmission type volume hologram. Speckle contrast was also investigated for the case where a relief hologram as a computer-generated hologram (CGH) having the above was used (Condition 2). In HDTV (high-definition television) video display applications, a speckle contrast of 6.0% or less is a standard (for example, WO / 2001/081996) as a level at which an uneven brightness pattern is hardly recognized when an observer observes with the naked eye. However, the measured speckle contrast was significantly lower than 6.0% under both conditions 1 and 2. When conditions 1 and 2 were actually observed with the naked eye, luminance unevenness (brightness unevenness) that could be visually recognized was not generated.

  On the other hand, when the laser light from the laser light source is shaped into a parallel light beam and incident on the spatial light modulator 30, that is, the spatial light modulator 30 of the projection display apparatus 10 shown in FIG. 65, when the coherent light from the light source mechanism 61 was incident as a parallel light beam without passing through the optical element 50 and the integrator rod 80, the speckle contrast was 20.7% (Condition 3). Under these conditions, a spot-like luminance unevenness pattern was observed quite noticeably by visual observation.

  Further, when the illumination device 40 is replaced with an LED (non-coherent light source) and light from the LED light source is incident on the spatial light modulator 30, that is, the space of the projection type video display device 10 shown in FIG. When non-coherent light from the LED light source is incident as a parallel light beam on the optical modulator 30 without passing through the scanning device 65, the optical element 50, and the integrator rod 80, the speckle contrast is 4.0% (conditions) 4). Under these conditions, brightness unevenness (brightness unevenness) that could be visually recognized by naked eye observation did not occur.

  The results of Condition 1 and Condition 2 were much better than the results of Condition 3, and were also better than the measurement results of Condition 4. As already mentioned, the problem of speckle generation is a problem inherent in the case of using a coherent light source such as a laser beam in practice, and it is necessary to consider in an apparatus using a non-coherent light source such as an LED. There is no problem. In addition, in condition 1 and condition 2, as compared with condition 4, an optical element 50 that can cause speckles is added. From these points, it can be said that Condition 1 and Condition 2 were sufficient to cope with speckle defects.

  In addition, according to the basic mode described above, the following advantages can be obtained.

  In the embodiment described above, the coherent light La, Lb, and Lc shaped into diffused light that spreads with a certain angle range by the light diffusing elements 55a, 55b, and 55c at any moment is converted into the integrator rod. 80 is incident. Due to the homogenizing function of the integrator rod 80, the coherent light La, Lb, and Lc is emitted from each position on the emission surface 80b of the integrator rod 80 at an arbitrary moment. Further, due to the homogenization function in the integrator rod 80, the coherent light La, Lb, Lc depends on the incident angle to the integrator rod 80 from each position on the exit surface 80b of the integrator rod 80 at an arbitrary moment. The light is emitted in a direction within a range having a certain range of angles.

  That is, due to the homogenizing function of the integrator rod 80, the coherent light La, Lb, Lc is incident on each position of the illuminated region LZ from various directions within a certain angle range at an arbitrary moment. In other words, at an arbitrary moment, the light diffracted by the hologram recording medium 55 and incident on each position of the illuminated area LZ is multiplexed in angle. Due to this angle multiplexing, the speckle pattern at each moment becomes complex or fine, and furthermore, the speckle pattern complicated or miniaturized by the time change of the angle becomes an uncorrelated spec as described above. As a pattern, it is superposed in time. As a result, by using the light diffusing elements 55a, 55b, and 55c in combination with the integrator rod 80, speckles are not very effectively noticeable to an observer who observes the image displayed on the screen 15. Can be made.

  Further, according to the homogenizing function of the integrator rod 80, the angular range in the emission direction of the coherent light La, Lb, and Lc emitted from the emission surface 80b of the integrator rod 80 is set at each position in the emission surface 80b for each moment. Can be made uniform. That is, by using the light diffusing elements 55a, 55b, and 55c in combination with the integrator rod 80, the speckle invisibility function at each position on the screen 15 can be achieved regardless of the diffraction characteristics of the light diffusing elements 55a, 55b, and 55c. It can be made uniform.

  Furthermore, according to the homogenizing function of the integrator rod 80, the amount of emitted light at each position on the exit surface 80b of the integrator rod 80 is effectively equalized. As a result, it is possible to illuminate the spatial light modulator 30 with the illumination light having a uniform light amount distribution, and thereby, the in-plane distribution of the brightness of the image projected on the screen 15 can be made uniform.

  In addition, according to the homogenizing function of the integrator rod 80, the diffused light from the light diffusing elements 55a, 55b, and 55c is incident on the entire area of the incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70, and further on the integrator rod 80. Even if the light does not enter the entire area of the surface 80a, the coherent lights La, Lb, and Lc are emitted from the entire area of the emission surface 80b of the integrator rod 80, and the entire area of the spatial light modulator 30 can be illuminated. That is, the integrator rod 80 also functions as an optical member for shaping and adjusting the beam form of the coherent light La, Lb, and Lc without relying only on the light diffusing elements 55a, 55b, and 55c. For this reason, it is not necessary to manufacture and arrange the light diffusion elements 55a, 55b, and 55c with high accuracy.

  Specifically, the image 6 reproduced by the coherent light La, Lb, and Lc incident on each position of the light diffusing elements 55a, 55b, and 55c is incident on the incident surfaces 70a1 and 70a1 of the synthesizer 70 with respect to the size and reproduction position. There is no need to precisely match 70a2 and 70a3. The image 6 reproduced by the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55a, 55b, 55c may be positioned so as to be positioned in the incident surfaces 70a1, 70a2, 70a3 of the synthesizer 70. That's fine. Accordingly, it is possible to design the diffusion angle of the light diffusion elements 55a, 55b, and 55c, that is, the setting of the diffraction angle with specifications that provide high diffraction efficiency.

  Further, as a practical problem, for example, coherent light La, Lb, and Lc incident on light diffusing elements 55a, 55b, and 55c including a hologram recording medium, a lens array that will be described later, and the like have scattering components instead of completely parallel light. Sometimes. When such coherent light La, Lb, Lc is used, the periphery of the region illuminated by the coherent light incident on each position of the light diffusing element, for example, the image 5 of the scattering plate 6 reproduced by the light diffusing element The surrounding area may be blurred. In this case, if the integrator rod is not used, a light amount loss corresponding to the degree of blur around the area illuminated by the coherent light occurs, or the periphery of the spatial light modulator 30 becomes dark. Therefore, even in such a case, a light amount loss occurs or the periphery of the spatial light modulator 30 becomes dark.

  In the embodiment described above, the image 6 reproduced by the coherent light La, Lb, Lc incident on each position of the light diffusing elements 55a, 55b, 55c is converted into the incident surfaces 81a, 82a, 82a of the integrator rods 81, 82, 83. As long as it is located within 83a, these problems can be addressed. From the above, the configuration of the illumination device 40, the projection device 20, and the projection type video display device 10 is simplified, and the manufacturing cost of the illumination device 40, the projection device 20, and the projection type video display device 10 is accordingly accompanied. Can also be reduced.

  However, the coherent light La, Lb, Lc incident on each position of the light diffusion elements 55a, 55b, 55c is incident after the traveling direction is changed by the light diffusion elements 55a, 55b, 55c. When the regions on the incident surfaces 70a1, 70a2, and 70a3 of the synthesizer 70 are partially overlapped with each other, are the same, or are the entire areas of the incident surfaces 70a1, 70a2, and 70a3. It is preferable in that the distribution of brightness irradiated on the screen 15 is made more uniform. In particular, if the incident areas on the incident surfaces 70a1, 70a2, and 70a3 of the synthesizing device 70 for the coherent light La, Lb, and Lc incident on the respective positions of the light diffusing elements 55a, 55b, and 55c are increased, the integrator is accordingly increased. The incident angle on the rod 80 changes over time in a larger angle region, and the emission angle region from each position on the emission surface 80b of the integrator rod 80 at an arbitrary moment is expanded. In this case, the incident angle area A of the modulated image incident on each position of the screen 15 is also expanded, and the speckle pattern is complicated or refined due to the multiplexing of the angles at each moment, and the speckle is reduced. It can be made invisible more effectively.

  Moreover, according to embodiment mentioned above, it projects from an illuminating device by adjusting a diffraction characteristic, especially a diffusion angle area, between the 1st-3rd light-diffusion elements 55a, 55b, 55c. The areas illuminated by the coherent lights La, Lb, and Lc can be made to overlap each other. In this case, it is possible to use the coherent light La, Lb, and Lc from the irradiation device 60 for image formation with high efficiency by arranging the spatial light modulator 30 in this overlapping region. Also, the use efficiency of light from the first to third light sources 61a, 61b, 61c is excellent.

  Further, in the above-described embodiment, the light diffusing elements 55a, 55b, 55c included in the optical element 50 are arranged on one plane, and the coherent light La, Lb, 55c from each of the light diffusing elements 55a, 55b, 55c is arranged. Lc is incident on one integrator rod 80. Therefore, the illumination device 40 can be configured in a compact size.

[Modification]
Various modifications can be made to the embodiment described based on the specific example illustrated in FIGS. Hereinafter, an example of modification will be described with reference to the drawings. In the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment are used, and redundant descriptions are omitted.

(Lighting device)
According to the embodiment described above, speckle can be effectively made inconspicuous. However, this effect is mainly due to the lighting device 40. Therefore, the lighting device 40 can be usefully used in various aspects. For example, the illumination device 40 can be used as simple illumination, and in this case, uneven brightness, uneven brightness, and flicker can be made inconspicuous.

(Spatial light modulator, projection optical system, screen)
According to the embodiment described above, speckle can be effectively made inconspicuous. However, this effect is mainly due to the lighting device 40. Even if this lighting device 40 is combined with various known spatial light modulators, projection optical systems, screens, etc., speckles can be effectively made inconspicuous. From this point, the spatial light modulator, the projection optical system, and the screen are not limited to those illustrated, and various known members, components, devices, and the like can be used. As an example, a relay optical system may be provided between the integrator rod 80 and the spatial light modulator 30 that can transmit cross-sectional information of light at the exit surface 80 b of the integrator rod 80 to the spatial light modulator 30. .

(Synthesizer)
In the embodiment described above, the synthesizing device 70 includes one synthesizing means 71 that can be constituted by a dichroic prism or the like, and first guiding means 72a and second guiding means 72b that can be constituted by a prism or the like. However, the present invention is not limited to this example. As an example, as shown in FIG. 7, the synthesizing device 70 may include two synthesizing units 71a and 71b. The synthesizing apparatus 70 in the example shown in FIG. 7 includes, for example, a first synthesizing unit 71a and a second synthesizing unit 71b that can include a dichroic prism, the first guiding unit 72a and the second guiding unit 72b described above, have. A portion of the first combining unit 71a facing the second light diffusing element 55b forms a second incident surface 70a2 that receives the second coherent light Lb from the second light diffusing element 55b. The first combining unit 71a is connected to the first guiding unit 72a and combines the first coherent light La and the second coherent light Lb. The portion of the second synthesizing unit 71b that faces the first synthesizing unit 71a forms an incident surface that receives the synthesized first coherent light La and second coherent light Lb. The second combining unit 71b is connected to the second guiding unit 72b, and the first coherent light La and the second coherent light Lb combined by the first combining unit 71a and the third coherent light from the second guiding unit 72b. The light Lc is synthesized.

(Irradiation device)
In the embodiment described above, the irradiation device 60 generates the combined light SL formed by combining a plurality of coherent lights La, Lb, and Lc having different wavelength ranges, and the traveling direction of the combined light SL from the light source mechanism 61. In the above example, the scanning device 65 and the separating unit 69 for separating the combined light SL from the scanning device 65 into a plurality of coherent lights La, Lb, and Lc having different wavelength ranges are shown. As shown in FIG. 8, coherent lights La, Lb, and Lc having different wavelength ranges from different light sources 61a, 61b, and 61c follow different optical paths without being combined, and corresponding light diffusion elements 55a, 55b, and 55c. You may make it inject into. Further, as shown in FIG. 9, the irradiation device 60 includes a plurality of light sources 61a, 61b, and 61c that respectively generate a plurality of coherent lights having different wavelength ranges, and a coherent light La, that is generated from the plurality of light sources 61a, 61b, and 61c. A scanning device 65 that changes the traveling direction of Lb and Lc so that the coherent light La, Lb, and Lc scans the light diffusing elements 55a, 55b, and 55c, and has a plurality of coherent wavelengths different from each other. The light La, Lb, and Lc may enter the same scanning device 65 from different directions, and the traveling directions may be changed in different directions. According to these modified examples, means for synthesizing and separating coherent light in a plurality of wavelength regions is not required.

  Further, a relay optical system that can transmit cross-sectional information of light from the scanning device 65 to the optical element 50 may be provided between the scanning device 65 and the optical element 50.

  Further, in the above-described embodiment, an example in which the incident angles of the coherent lights La, Lb, and Lc incident on the light diffusing elements 55a, 55b, and 55c so as to scan on the light diffusing elements 55a, 55b, and 55c are constant. However, the present invention is not limited to this. As shown in FIGS. 8 and 9, when the coherent light La, Lb, and Lc is incident on the light diffusing elements 55a, 55b, and 55c so as to scan the light diffusing elements 55a, 55b, and 55c, The incident angles of La, Lb, and Lc on the light diffusing elements 55a, 55b, and 55c may be changed with time.

  The scanning device 65 deflects the traveling direction of the coherent light traveling in various traveling directions from the reflecting device 66 to the same direction ds, and the uniaxial rotation type reflecting device 66 that changes the traveling direction of the coherent light by reflection. Although the example which has the deflection | deviation element 67 to be shown was shown, it is not restricted to this. As shown in FIG. 10, in the reflection device 66 of the scanning device 65, the mirror (reflection surface 66a) of the reflection device 66 intersects not only the first rotation axis RA1 but also the first rotation axis RA1. It may be rotatable about the second rotation axis RA2. In the example shown in FIG. 10, the second rotation axis RA2 of the mirror 66a is the first time extending parallel to the Y axis of the XY coordinate system defined on the plate surfaces of the light diffusing elements 55a, 55b, and 55c. It is orthogonal to the movement axis RA1. Since the mirror 66a is rotatable about both the first axis RA1 and the second axis RA2, the incident point IP1 of the coherent light from the reflection device 66 on the surface of the deflecting element 67 is in a two-dimensional direction. It becomes possible to move. As a result, the incident point IP2 of the coherent light from the irradiation device 60 to the optical element 50 can move in a two-dimensional direction on the plate surfaces of the light diffusing elements 55a, 55b, and 55c. As an example, as shown in FIG. 10, the incident point IP1 of the coherent light to the deflecting element 67 may be moved on the circumferential scanning path PW1, and the coherent light to the optical element 50 may be moved. The incident point IP2 may be moved on the circumferential scanning path PW2.

  The scanning device 65 may include two or more reflection devices (mirror devices) 66. In this case, even if the reflecting surface (mirror) 66a of each reflecting device 66 is rotatable only about a single axis, the incident point IP2 of the coherent light from the irradiation device 60 to the optical element 50 is The light diffusion elements 55a, 55b, and 55c can be moved in a two-dimensional direction on the plate surfaces.

  Specific examples of the reflection device 66 included in the scanning device 65 include a MEMS mirror and a polygon mirror.

  The scanning device 65 may be configured to include a reflection device that changes the traveling direction of coherent light by reflection, for example, a device other than the mirror device 66 described above. For example, the scanning device 65 may include a refractive prism, a lens, and the like.

  On the other hand, specific examples of the deflection element 67 included in the scanning device 65 include a Fresnel lens, a hologram lens, a diffractive optical element (DOE), and the like in addition to the above-described resin and glass lenses. Can do.

  However, in the first place, the scanning device 65 is not essential, and the light source mechanism 61 and the first to third light sources 61a, 61b, 61c of the irradiation device 60 can be displaced with respect to the optical element 50, that is, move, swing, and rotate. Coherent light La, Lb emitted from the light source mechanism 61 and the first to third light sources 61a, 61b, 61c due to the displacement of the light source mechanism 61 and the first to third light sources 61a, 61b, 61c with respect to the optical element 50. , Lc may scan the light diffusion elements 55a, 55b, 55c. That is, in addition to continuously changing the optical path of the coherent light La, Lb, and Lc emitted from the light source mechanism 61 and the first to third light sources 61a, 61b, and 61c, or Instead of continuously changing the optical path of the coherent light La, Lb, Lc emitted from the third light sources 61a, 61b, 61c, the orientation of the light source mechanism 61 and the first to third light sources 61a, 61b, 61c, For example, the emission direction of the coherent light La, Lb, and Lc may be changed from the light source mechanism 61 or the first to third light sources 61a, 61b, and 61c by changing the arrangement, orientation, and the like.

  In the above-described embodiment, an example in which the irradiation device 60 emits three types of coherent light having different wavelength ranges has been described, but the present invention is not limited thereto. The irradiation device 60 may emit two types of coherent light having different wavelength ranges, or may emit four or more types of coherent light having different wavelength ranges.

(Optical element)
In the above-described embodiment, the example in which the plurality of light diffusion elements 55a, 55b, and 55c included in the optical element 50 are arranged on the same plane has been described, but the present invention is not limited to this. For example, as shown in FIG. 8, the light diffusing elements 55a, 55b, and 55c may not be arranged on the same plane. In the example shown in FIG. 8, the optical element 50 is composed of three light diffusing elements 55a, 55b, and 55c arranged separately.

  In the above-described embodiment, the optical element 50 includes the transmission type volume hologram 55 using the photopolymer. However, as described above, the present invention is not limited thereto. The optical element 50 may include a volume hologram that is recorded using a photosensitive medium including a silver salt material. Further, the optical element 50 may include a relief type (emboss type) hologram recording medium, or may include a transmission type volume hologram recording medium.

  Further, in the exposure process shown in FIG. 5, a so-called Fresnel type hologram recording medium, that is, the light diffusion elements 55a, 55b, and 55c shown in FIGS. A Fourier transform type hologram recording medium obtained by recording, that is, the light diffusion elements 55a, 55b, and 55c shown in FIG. 4 may be created. As shown in FIG. 4, when a Fourier transform type hologram recording medium is used, the Fourier transform lens 53 may be used also during image reproduction.

  The striped pattern to be formed on the light diffusing elements 55a, 55b, and 55c, for example, the refractive index modulation pattern and the concave / convex pattern, does not use the actual object light Lo and the reference light Lr, but the planned reproduction illumination light La. May be designed using a computer based on the wavelength and the incident direction of the image, the shape and position of the image to be reproduced, and the like. The light diffusing elements 55a, 55b and 55c thus obtained are called computer-generated holograms.

  Furthermore, the light diffusing elements 55a, 55b, and 55c are not limited to holographic optical elements, but have a lens array that changes and diffuses the traveling direction of coherent light irradiated to each position, and also has a light diffusing function. You may make it comprise the diffused plate which was made. Specific examples of the lens array that functions as a light diffusing element include a total reflection type or a refractive type Fresnel lens or a fly-eye lens provided with a diffusion function. The element lenses of the lens array may be arranged periodically or irregularly. Also in such an illuminating device 40, the irradiating device 60 scans the light diffusing element formed of the lens array so that the coherent light scans the optical element 50, and the irradiating device 60 emits the coherent light. If the coherent light incident on each position of the optical element 50 is diffused and incident on the synthesizing device 70, the speckle can be effectively made inconspicuous. Further, in the aspect in which the optical element 50 includes a lens array or a diffusion plate, other configurations such as the irradiation device 60, the spatial light modulator 30, and the projection optical system 25 are similar to the aspect in which the optical element 50 includes a hologram recording medium. The screen 15 can be variously modified, for example, modified or changed.

  In the above-described embodiment, the example in which the light diffusing elements 55a, 55b, and 55c are arranged apart from the incident surfaces 70a1, 70a2, and 70a3 of the synthesizing device 70 has been described. The light diffusing elements 55 a, 55 b, and 55 c may be provided on the whole area or a part of the incident surface 80 a of the integrator rod 80. According to such a form, all the coherent light La, Lb, and Lc that passes through the light diffusing elements 55a, 55b, and 55c can be incident on the integrator rod 80, and the utilization efficiency of the coherent light La, Lb, and Lc From the viewpoint of

(Lighting method)
In the above-described embodiment, the light diffusing element is configured such that the irradiation device 60 can scan the coherent light on the optical element 50 in a one-dimensional direction, and includes the hologram recording medium, the lens array, or the like of the optical element 50. An example is shown in which 55a, 55b, and 55c are configured to diffuse (spread and diverge) the coherent light irradiated to each position in a two-dimensional direction. However, as described above, the present invention is not limited to such an example. For example, the irradiation device 60 is configured to be able to scan the coherent light on the optical element 50 in a two-dimensional direction, and The light diffusing elements 55a, 55b, and 55c including the hologram recording medium, the lens array, and the like of the optical element 50 diffuse the coherent light irradiated to each position in a two-dimensional direction (spread and diverge). Thereby, the illuminating device 40 may illuminate the two-dimensional illuminated area LZ (the aspect already described with reference to FIG. 10).

  Further, as already mentioned, the irradiation device 60 is configured to be able to scan the coherent light in the one-dimensional direction on the optical element 50, and is configured from a hologram recording medium, a lens array, or the like of the optical element 50. The light diffusing elements 55a, 55b, and 55c may be configured to diffuse (spread and diverge) the coherent light irradiated to each position in a one-dimensional direction. In this aspect, the scanning direction of the coherent light by the irradiation device 60 may be parallel to the diffusion direction (expansion direction) of 55 configured by the hologram recording medium, the lens array, or the like of the optical element 50.

  Furthermore, the light diffusing device 60 is configured so that the irradiation device 60 can scan the coherent light in the one-dimensional direction or the two-dimensional direction on the optical element 50, and is configured by a hologram recording medium, a lens array, or the like of the optical element 50. The elements 55a, 55b, and 55c may be configured to diffuse (spread and diverge) the coherent light irradiated to each position in a one-dimensional direction.

(Combination of modified examples)
In addition, although the some modification with respect to embodiment mentioned above was demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

5 Image 6 Scattering plate 10 Projection image display device 15 Screen 20 Projection device 25 Projection optical system 30 Spatial light modulator 40 Illumination device 50 Optical element 53 Lens 55a First light diffusion element 55b Second light diffusion element 55c Third light diffusion Element 58 Hologram photosensitive material 60 Irradiation device 61 Light source mechanism 61a Light source (first light source)
61b Light source (second light source)
61c Light source (third light source)
62 Combining means 65 Scanning device 66 Mirror device (reflection device)
66a Mirror (reflective surface)
67 Deflector 69 Separating device 69a First separating mirror device 69b Second separating mirror device 69c Third separating mirror device 70 Combining device 70a1 First incident surface 70a2 Second incident surface 70a3 Third incident surface 70b Outgoing surface 71 Synthetic prism 72a First 1 guidance means 72b 2nd guidance means 80 Integrator rod 80a Incident surface 80b Outgoing surface

Claims (11)

An optical element including a first light diffusing element and a second light diffusing element;
First coherent light in a first wavelength region scans on the first light diffusing element, and second coherent light in a second wavelength region different from the first wavelength region scans on the second light diffusing element. And an irradiation device that irradiates the optical element with a plurality of coherent lights having different wavelength ranges,
A synthesis device that synthesizes the first coherent light from the first light diffusing element and the second coherent light from the second light diffusing element;
An integrator rod on which the first coherent light and the second coherent light synthesized by the synthesizing device are incident ;
The illuminating device , wherein the light diffusing elements included in the optical element are arranged on one plane .   An optical element including a first light diffusing element and a second light diffusing element;
  First coherent light in a first wavelength region scans on the first light diffusing element, and second coherent light in a second wavelength region different from the first wavelength region scans on the second light diffusing element. And an irradiation device that irradiates the optical element with a plurality of coherent lights having different wavelength ranges,
  A synthesis device that synthesizes the first coherent light from the first light diffusing element and the second coherent light from the second light diffusing element;
  An integrator rod on which the first coherent light and the second coherent light synthesized by the synthesizing device are incident;
  The irradiation apparatus includes: a light source mechanism that generates combined light obtained by combining a plurality of coherent lights having different wavelength ranges; a scanning device that changes a traveling direction of the combined light from the light source mechanism; and the scanning device. A separating device that separates the combined light into a plurality of coherent lights having different wavelength ranges. The first coherent light incident on each position of the first light diffusing element from the irradiation device illuminates a region overlapping at least in part after exiting from the integrator rod,
The second coherent light incident on each position of the second light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
Wherein at least a portion is illuminated to overlap with the first coherent light, wherein at least a portion is illuminated to overlap by said second coherent light, at least partially overlap, according to claim 1 or 2 Lighting device. The first coherent light incident on each position of the first light diffusing element is incident on an overlapping region in at least part of the incident surface of the integrator rod, and is incident on each position of the second light diffusing element. 4. The illumination device according to claim 1, wherein each of the second coherent lights is incident on an overlapping region in at least a part on an incident surface of the integrator rod. 5. The optical element further includes a third light diffusing element different from the first light diffusing element and the second light diffusing element,
The plurality of coherent lights with different wavelength ranges emitted from the irradiation device further include third coherent light in a third wavelength range different from the first wavelength range and the second wavelength range, Irradiating the third coherent light so that the third coherent light scans on the third light diffusing element;
The third coherent light from the third light diffusing element is combined with the first coherent light from the first light diffusing element and the second coherent light from the second light diffusing element by the combining device. The lighting device according to claim 1 or 2 , wherein The first coherent light incident on each position of the first light diffusing element from the irradiation device illuminates a region overlapping at least in part after exiting from the integrator rod,
The second coherent light incident on each position of the second light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
The third coherent light incident on each position of the third light diffusing element from the irradiation device illuminates a region overlapping at least partly after exiting from the integrator rod,
The at least a portion illuminated to overlap by the first coherent light, the at least a portion illuminated to overlap by the second coherent light, and the at least a portion illuminated to overlap by the third coherent light are: The lighting device of claim 5 , wherein the lighting device overlaps at least partially. The first coherent light incident on each position of the first light diffusing element is incident on an overlapping region in at least part of the incident surface of the integrator rod, and is incident on each position of the second light diffusing element. The second coherent light is incident on an overlapping region in at least part of the incident surface of the integrator rod, and the third coherent light is incident on each position of the third light diffusing element, respectively. The illuminating device according to claim 5 , wherein the illuminating device is incident on an overlapping region in at least a part on an incident surface of the illuminating device.   The lighting device according to claim 1, wherein each light diffusing element is a transmissive light diffusing element.   The illumination device according to claim 1, wherein an incident surface of the integrator rod is connected to the synthesis device. The lighting device according to any one of claims 1 to 9 ,
A spatial light modulator that is illuminated by the illumination device, Ru includes a projection device. The lighting device according to any one of claims 1 to 9 ,
A spatial light modulator illuminated by the illumination device;
A screen projected modulated image obtained by the spatial light modulator, Ru with a projection type image display apparatus.

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