WO2012141254A1 - Dispositif d'éclairage, dispositif de projection, et dispositif d'affichage d'images de type projection - Google Patents

Dispositif d'éclairage, dispositif de projection, et dispositif d'affichage d'images de type projection Download PDF

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Publication number
WO2012141254A1
WO2012141254A1 PCT/JP2012/060042 JP2012060042W WO2012141254A1 WO 2012141254 A1 WO2012141254 A1 WO 2012141254A1 JP 2012060042 W JP2012060042 W JP 2012060042W WO 2012141254 A1 WO2012141254 A1 WO 2012141254A1
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Prior art keywords
coherent light
incident
light
optical element
hologram recording
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PCT/JP2012/060042
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English (en)
Japanese (ja)
Inventor
牧夫 倉重
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大日本印刷株式会社
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Publication of WO2012141254A1 publication Critical patent/WO2012141254A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/32—Systems for obtaining speckle elimination

Definitions

  • the present invention relates to an illumination device that illuminates an illuminated area with coherent light, a projection device that projects coherent light, and a projection-type image display device that displays an image using coherent light, and in particular, generation of speckle is inconspicuous.
  • the present invention relates to a lighting device, a projection device, and a projection type image display device that can be made to operate.
  • Projection-type image display devices having a screen and a projection device that projects image light on the screen are widely used.
  • 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 DMD (Digital Micromirror Device), and this 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.
  • optical projectors Various types of projection devices have been proposed, including commercially available products called “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.
  • a white light source such as a high-pressure mercury lamp
  • a dichroic mirror for example, 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 generated modulated image for each primary color is synthesized by a cross dichroic prism and projected onto a screen.
  • high-intensity discharge lamps such as high-pressure mercury lamps have a relatively short life, and when used for optical projectors or the like, it is necessary to replace the lamps frequently. Furthermore, the use of a high-pressure mercury lamp used mercury from the viewpoint of environmental load can not be said to be preferable. Further, since it is necessary to use a relatively large optical system such as a dichroic mirror in order to extract the light of each primary color component, there is a problem that the entire apparatus becomes large.
  • a coherent light source such as a laser.
  • 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.
  • the light source can generate light having a single wavelength, a spectroscopic device such as a dichroic mirror is not necessary, and the entire device can be reduced in size.
  • speckle is a speckled pattern that appears when a scattering surface is irradiated with laser light or other coherent light. When it appears on a screen, it is observed as speckled brightness irregularities (brightness irregularities). It becomes a factor having a physiological adverse effect on the person.
  • 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. .
  • Non-Patent Document 1 below, a detailed theoretical discussion of the generation of speckles have been made.
  • the speckle is reduced by irradiating a scattering plate with laser light, guiding the scattered light obtained therefrom to a spatial light modulator, and rotating the scattering plate by a motor.
  • Speckle is not a problem specific to a projection device or a projection-type image display device, but is a problem in various devices in which an illumination device that illuminates coherent light in an illuminated area.
  • a scanner that reads image information incorporates an illumination device that illuminates an object to be read.
  • speckle is generated by the light that illuminates the object to be read, the image information cannot be read accurately.
  • a scanner using coherent light needs to perform special processing such as image correction.
  • an object of the present invention is to provide an illuminating device capable of making speckles inconspicuous, a projection device including the illuminating device, and a projection-type image display device.
  • the lighting device comprises: An optical element capable of diffusing coherent light; A plurality of coherent light sources that emit coherent light of the same wavelength, and The optical element has a plurality of incident areas; The coherent light from each coherent light source is incident on a corresponding incident region of the optical element; The coherent light that has entered and diffused into each incident region of the optical element illuminates regions that overlap each other at least in part.
  • An incident-side optical system that guides the coherent light to each incident region of the optical element may be provided between the plurality of coherent light sources and the optical element.
  • the incident side optical system may include an imaging optical system that forms an image of each of the coherent light sources on a corresponding incident region of the optical element.
  • the incident side optical system may be a lens, a diffractive optical element, or a prism.
  • An optical fiber that guides the coherent light to the corresponding incident region of the optical element may be provided between each coherent light source and the corresponding incident region of the optical element.
  • the optical element may be a hologram recording medium.
  • the optical element may be a lens array that changes a traveling direction of incident light.
  • the optical element may be a diffusion plate that changes a traveling direction of incident light.
  • the diffusion plate may be opal glass, frosted glass, or a resin diffusion plate.
  • the plurality of coherent light sources may be built in a laser array.
  • the plurality of coherent light sources may be a plurality of independent laser light sources.
  • the projection apparatus A lighting device according to the invention as described above; A spatial light modulator disposed at a position illuminated by coherent light from the illumination device.
  • a first projection display apparatus is: A projection device according to the invention as described above; And a screen on which a modulated image obtained on the spatial light modulator is projected.
  • a second projection type video display device is: A lighting device according to the invention as described above; And a screen disposed at a position illuminated by coherent light from the illumination device.
  • speckles on an illuminated area or a surface on which an image is projected can be effectively made inconspicuous.
  • FIG. 1 is a diagram for explaining a basic form of an embodiment according to the present invention, and shows a schematic configuration of a lighting device, a projection apparatus, and a projection type video display apparatus as one specific example of the basic form.
  • FIG. FIG. 2 is a diagram illustrating the illumination device illustrated in FIG. 1.
  • FIG. 3 is a diagram for explaining an exposure method for producing a hologram recording medium that forms an optical element of the illumination device of FIG.
  • FIG. 4 is a diagram for explaining the operation of the hologram recording medium manufactured through the exposure method of FIG.
  • FIG. 5 is a perspective view of the lighting device shown in FIG.
  • FIG. 6 is a view showing a modification of the irradiation apparatus.
  • FIG. 7 is a diagram showing another modification of the irradiation apparatus.
  • FIG. 1 is a diagram for explaining a basic form of an embodiment according to the present invention, and shows a schematic configuration of a lighting device, a projection apparatus, and a projection type video display apparatus as one specific example
  • FIG. 8 is a diagram for explaining a modification of the optical element, and is a plan view showing the optical element together with a corresponding illuminated region.
  • FIG. 9 is a diagram for explaining another modified example of the optical element, and is a plan view showing the optical element together with a corresponding illuminated region.
  • FIG. 10 is a view corresponding to FIG. 5, and is a perspective view for explaining another modification of the irradiation apparatus and its operation.
  • FIG. 11 is a diagram for explaining a modification of the incident-side optical system, and is a diagram illustrating a schematic configuration of the illumination device, the projection device, and the projection-type image display device.
  • FIG. 12 is a diagram for explaining another modified example of the incident side optical system, and is a diagram illustrating a schematic configuration of the illumination device, the projection device, and the projection type video display device.
  • the illumination device, projection device, and projection-type image display device have a configuration that enables effective prevention of speckle as a basic configuration.
  • FIG. 1 to FIG. 12 are diagrams for explaining an illumination device, a projection device, a projection type video display device, and a modification thereof according to an embodiment of the present invention.
  • an illumination device, a projection device, and a projection-type image display device according to a basic form of one embodiment will be described. Thereafter, the lighting device according to the basic embodiment, an example of modifications to the projection device and a projection type image display device will be described.
  • 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.
  • the spatial light modulator 30 for example, a transmissive liquid crystal microdisplay can be used.
  • 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 modulated image (video light) thus obtained is projected onto the screen 15 at the same magnification or scaled by the projection optical system 25.
  • the modulated image is displayed on the screen 15 at the same magnification or at a variable magnification, usually enlarged, and the observer can observe the image.
  • a reflection type micro display can be used as the spatial light modulator 30, a reflection type micro display.
  • 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.
  • a MEMS element such as DMD (Digital Micromirror Device) as the spatial light modulator 30.
  • DMD Digital Micromirror Device
  • 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.
  • Screen 15 may be configured as a transmission type screen, it may be configured as a reflective screen.
  • 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.
  • 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. .
  • the coherent light projected on the screen 15 is diffused and recognized as an image by the observer.
  • the coherent light projected on the screen interferes by diffusion and causes speckle.
  • the illumination device 40 described below includes a plurality of coherent light beams having different incident angles and not coherent to each other, and the spatial light modulator 30 is overlaid.
  • the illuminated area LZ is illuminated at the same time. More specifically, the illuminating device 40 described below illuminates the illuminated region LZ simultaneously with a plurality of diffused light composed of coherent light, but the incident angles of these diffused light are different from each other.
  • the coherent lights projected on the screen 15 also have different incident angles, so that speckle patterns are generated on the screen 15 by the number of coherent lights, and these speckle patterns do not interfere with each other and are spatially generated. Is superimposed on. Therefore, speckles generated by the diffusion of coherent light are superimposed and become inconspicuous.
  • an illuminating device 40 will be described in more detail.
  • Lighting apparatus shown in Figures 1 and 2 40 the optical element 50 to direct the traveling direction of the coherent light to the illumination zone LZ diffuse coherent light, an irradiation device 60 for irradiating the coherent light to the optical element 50 ,have.
  • the optical element 50 is capable of diffusing coherent light with respect to at least the entire illuminated area LZ at each point.
  • the optical element 50 includes a hologram recording medium 55 that can reproduce the image 5 of the scattering plate 6.
  • the optical element 50 is formed from a hologram recording medium 55.
  • the hologram recording medium 55 constituting the optical element 50 in the illustrated example can receive the coherent light emitted from the irradiation device 60 as the reproduction illumination light La, and can diffract the coherent light with high efficiency.
  • the hologram recording medium 55 can reproduce the image 5 of the scattering plate 6 by diffracting coherent light incident on each position, in other words, each minute region that should be called each point. ing.
  • the hologram recording medium 55 has three incident areas 55a, 55b, and 55c. However, each of the incident areas 55a, 55b, and 55c represents an area where the corresponding coherent light can enter, and the hologram recording medium 55 may not be actually partitioned.
  • the irradiation device 60 is incident region 55a of the coherent light corresponding on the hologram recording medium 55 of the optical element 50, 55b, to be incident only 55c, the optical element 50, the same wavelength is not interfering with each other
  • a plurality of coherent lights, here, three coherent lights are irradiated.
  • the region on the hologram recording medium 55 irradiated with certain coherent light by the irradiation device 60 is a part of the surface of the hologram recording medium 55, and in particular, in the example shown in the drawing, is a minute region to be called a point.
  • speckles are caused.
  • each coherent light irradiated from the irradiation device 60 onto the hologram recording medium 55 is placed at a corresponding position (corresponding point or corresponding region (hereinafter the same)) on the hologram recording medium 55.
  • a corresponding position corresponding point or corresponding region (hereinafter the same)
  • the coherent light that is diffused by being incident on the incident areas 55a, 55b, and 55c of the hologram recording medium 55 from the irradiation device 60 is diffracted by the hologram recording medium 55 and illuminates areas that overlap each other at least partially.
  • the coherent light incident on the incident areas 55a, 55b, and 55c of the hologram recording medium 55 from the irradiation device 60 is diffracted by the hologram recording medium 55 to illuminate the same illuminated area LZ. It is supposed to be. More specifically, as shown in FIG. 2, the coherent light that has entered the three incident areas 55a, 55b, and 55c of the hologram recording medium 55 from the irradiation device 60 is superimposed on the illuminated area LZ, and the scattering plate 6 The image 5 is reproduced. That is, the coherent light that has entered the three positions of the hologram recording medium 55 from the irradiation device 60 is diffused by the optical element 50 and simultaneously enters the illuminated area LZ.
  • the coherent light incident and diffracted on each of the incident regions 55a, 55b, and 55c of the hologram recording medium 55 is on this virtual surface.
  • the corresponding regions in are at least partially illuminated so as to overlap each other.
  • a transmission type volume hologram using a photopolymer is used as the hologram recording medium 55 enabling the diffraction action of such coherent light.
  • the hologram recording medium 55 is manufactured by using the scattered light from the actual scattering plate 6 as the object light Lo.
  • FIG. 3 shows a state in which the hologram photosensitive material 58 having photosensitivity that forms the hologram recording medium 55 is exposed to the reference light Lr and the object light Lo, which are coherent light beams having coherence with each other. ,It is shown.
  • the reference light Lr for example, laser light from a laser light source that oscillates laser light in a specific wavelength region is used.
  • the laser light that forms the reference light Lr is incident on the condensing element 7 as a parallel light beam parallel to the optical axis of the condensing element 7.
  • the reference light Lr passes through the condensing element 7, so that it is shaped (converted) into a convergent light beam from the parallel light beam so far, and is incident on the hologram photosensitive material 58.
  • the focal point position FP of the convergent light beam Lr is in a position beyond the hologram photosensitive material 58.
  • the hologram photosensitive material 58 is disposed between the condensing element 7 and the focal position FP of the convergent light beam Lr collected by the condensing element 7.
  • the object light Lo is incident on the hologram photosensitive material 58 as scattered light from the scattering plate 6 made of, for example, opal glass.
  • the hologram recording medium 55 to be manufactured is a transmission type
  • the object light Lo is incident on the hologram photosensitive material 58 from the same plane 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.
  • a parallel light beam parallel to the normal direction to the plate surface of the scattering plate 6 is incident on and scattered by the scattering plate 6, and the scattered light transmitted through the scattering plate 6 is the object light Lo.
  • the light enters the hologram photosensitive material 58.
  • the object light Lo from the scattering plate 6 is incident on the hologram photosensitive material 58 with a substantially uniform light amount distribution. Is possible.
  • the object light Lo 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 hologram recording medium 55 reproduces the image 5 of the scattering plate 6 with the same brightness, and the reproduced scattering plate 6 It can be realized that the image 5 is observed with substantially uniform brightness.
  • the hologram recording material 58 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.
  • 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 hologram recording material 55 is obtained.
  • FIG. 4 shows the diffraction action (reproduction action) of the hologram recording medium 55 obtained through the exposure process of FIG.
  • the hologram recording medium 55 formed from the hologram photosensitive material 58 of FIG. 3 is light having the same wavelength as the laser beam used in the exposure process, and the optical path of the reference light Lr in the exposure process. The light traveling in the opposite direction satisfies the diffraction condition. That is, as shown in FIG. 4, the reference point SP positioned with respect to the hologram recording medium 55 in the same positional relationship as the relative position of the focal point FP (see FIG. 3) with respect to the hologram photosensitive material 58 during the exposure process.
  • the reproduction illumination light La is diffracted in the hologram recording medium 55, the relative positions of the scattering plate 6 on the hologram photosensitive material 58 during the exposure process A reproduced image 5 of the scattering plate 6 is generated at a specific position with respect to the hologram recording medium 50 that has the same positional relationship as (see FIG. 3).
  • the reproduction light Lb for generating the reproduction image 5 of the scattering plate 6, that is, the light formed by diffracting the reproduction illumination light La by the hologram recording medium 55 travels from the scattering plate 6 toward 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 been emitted.
  • the object light Lo from the entire area of the exit surface 6 a of the scattering plate 6 is incident on each position on the hologram photosensitive material 58, and as a result, information on the entire exit surface 6 a is placed on each position of the hologram recording medium 55. Each is recorded. For this reason, each light which forms the divergent light beam from the reference point SP functioning as the reproduction illumination light La shown in FIG. 4 is incident on each position of the hologram recording medium 55 independently and has the same contour. an image 5 of the scattering plate 6 having, can be reproduced at the same position to each other (the illumination zone LZ).
  • the irradiation device 60 that irradiates the optical element 50 including the hologram recording medium 55 with the coherent light can be configured as follows.
  • the irradiation device 60 includes a laser array 62 and a concave lens 71 as the incident side optical system 70.
  • the laser array 62 includes three laser light sources (coherent light sources) 61a, 61b, and 61c each generating coherent light having the same wavelength in one chip.
  • the coherent lights from the different solid laser light sources 61a, 61b, 61c are not coherent with each other.
  • this basic mode an example including three laser light sources 61a, 61b, and 61c will be described in order to clarify the explanation, but it is preferable that the number of laser light sources is large. This is because, as will be described later, speckles can be made inconspicuous as the number of laser light sources increases.
  • the concave lens 71 is disposed between the laser light sources 61a, 61b, 61c and the optical element 50.
  • a laser light source 61a of the laser array 62, 61b, 61c emits coherent light in a direction parallel.
  • the concave lens 71 guides each coherent light to the corresponding incident areas 55a, 55b, and 55c of the hologram recording medium 55 so that these parallel coherent lights spread. Thereby, the coherent light from each laser light source 61a, 61b, 61c is incident only on the corresponding incident area of the hologram recording medium 55.
  • the coherent light from the concave lens 71 is coherent light that can form one light beam from the reference point SP in FIG.
  • the incident side optical system 70 may be a diffractive optical element or a prism.
  • the positions of the laser light source 61a and the concave lens 71 are determined so that the coherent light is not incident on a position deviated from the incident region 55a.
  • only coherent light from the laser light source 61b is incident on a predetermined position of the incident area 55b, and the image 5 of the scattering plate 6 is reproduced over the entire illuminated area LZ.
  • only the coherent light from the laser light source 61c is incident on a predetermined position of the incident region 55c, and the image 5 of the scattering plate 6 is reproduced over the entire illuminated region LZ.
  • the illumination zone LZ is no interference with each other, the coherent light from the incident area 55a, will be illuminated simultaneously with coherent light from the coherent light and the incident region 55c from the incident area 55b.
  • each coherent light whose traveling direction is adjusted by the concave lens 71 is reproduced illumination light La (see FIG. 4) that can form one light beam diverging from the reference point SP, and the hologram recording medium 55 of the optical element 50. Can be incident.
  • coherent light beams having no interference from the laser light sources 61a, 61b, and 61c are incident on three positions on the hologram recording medium 55, and are incident on the respective positions on the hologram recording medium 55.
  • the image 5 of the scattering plate 6 having coherent light having the same contour is reproduced simultaneously at the same position (illuminated region LZ).
  • FIG. 5 shows a perspective view of the configuration of the illumination device 40 shown in FIG.
  • the incident points IP1, IP2, and IP3 of the coherent light from the irradiation device 60 to the optical element 50 are XY coordinate systems defined on the plate surface of the hologram recording medium 55, that is, XY.
  • the plane is located on a straight line parallel to the X axis of the XY coordinate system that is parallel to the plate surface of the hologram recording medium 55.
  • the reproducing light Lb from the incident point IP2 is omitted.
  • the hologram recording material 58 may shrink when the hologram recording medium 55 is produced.
  • the traveling direction of the light incident on the hologram recording medium 55 of the optical element 50 does not take exactly the same path as the one light beam included in the divergent light beam from the reference point SP, it is illuminated.
  • the image 5 can be reproduced in the region LZ.
  • the laser light sources 61a, 61b, 61c of the irradiation device 60 generate three coherent lights of the same wavelength that travel in parallel. As described above, these coherent lights are not coherent.
  • the traveling direction of these coherent lights can be changed by the concave lens 71.
  • the concave lens 71 causes the coherent lights to be incident on three positions (incident areas) on the hologram recording medium 55 at an incident angle that satisfies the Bragg condition at the positions so as not to overlap each other.
  • the coherent light incident on the three positions is superimposed on the illuminated region LZ by the diffraction on the hologram recording medium 55, and the image 5 of the scattering plate 6 is simultaneously reproduced.
  • the coherent light that has entered the three positions of the hologram recording medium 55 from the irradiation device 60 is diffused by the optical element 50 and enters the entire illuminated area LZ.
  • the irradiation device 60 simultaneously illuminates the illuminated area LZ with coherent light having no coherence.
  • the spatial light modulator 30 is arranged at a position overlapping the illuminated area LZ of the illumination device 40. For this reason, the spatial light modulator 30 is illuminated in a planar shape by the illumination device 40, and forms an image by selecting and transmitting the coherent light for each pixel.
  • This image is projected onto the screen 15 by the projection optical system 25.
  • Coherent light projected on the screen 15 is diffused, become recognized as image to the observer. However, at this time, the coherent light projected on the screen interferes by diffusion and causes speckle.
  • 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. 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.
  • the irradiation device 60 described above irradiates three coherent lights having no interference with each other on the corresponding positions (incident areas) of the hologram recording medium 55 of the optical element 50. Further, the coherent light incident on the three positions of the hologram recording medium 55 from the irradiation device 60 simultaneously illuminates the entire illuminated area LZ with the coherent light, but the coherent light illuminates the illuminated area LZ. The illumination directions of light are different from each other.
  • uncorrelated coherent light scattering patterns are multiplexed and observed at each position on the screen 15 displaying an image. 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.
  • speckles observed by humans include not only speckles on the screen caused by scattering of coherent light on the screen 15, but also scattering of coherent light before being projected on the screen. Speckle on the projection device side can also occur.
  • the speckle pattern generated on the projection device side is projected onto the screen 15 via the spatial light modulator 30 so that it can be recognized by the observer.
  • coherent light having no coherence incident on three positions of the hologram recording medium 55 illuminates the entire illuminated area LZ on which the spatial light modulator 30 is superimposed. To come.
  • the hologram recording medium 55 forms a new wavefront that is separate from the wavefront used to form the speckle pattern, and the illumination area LZ and further the spatial light modulator 30 are formed in a complex and uniform manner. Through this, the screen 15 is illuminated. Due to the formation of a new wavefront on the hologram recording medium 55, the speckle pattern generated on the projection apparatus side is made invisible.
  • Non-Patent Document 1 proposes a method that uses a numerical value called speckle contrast (unit%) as a parameter indicating the degree of speckle generated on the screen.
  • speckle contrast is defined when displaying a test pattern image to take originally uniform luminance distribution, the standard deviation of the variation in the actually occurs brightness on the screen, as divided by the average value of the brightness Amount. That is, this speckle contrast is an amount proportional to the reciprocal of the square root of the number of modes. In this basic form, the number of modes is the number of laser light sources. Therefore, this speckle contrast is proportional to the reciprocal of the square root of the number of laser light sources.
  • the three laser light sources 61a illustrated, 61b, 61c not only speckle in a state with more of the laser light source
  • it was 5.0% (Condition 1).
  • 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.
  • the speckle contrast in the case of using a relief hologram as a computer-generated hologram (CGH) having a value of 6.2 was 6.2% (Condition 2).
  • 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.
  • the basic form described above satisfies this standard to some extent.
  • brightness unevenness (brightness unevenness) that could be visually recognized did not occur.
  • the laser light from one laser light source is shaped into a parallel light beam and made incident on the spatial light modulator 30 without using a plurality of laser light sources, that is, the projection-type image display device shown in FIG.
  • the speckle contrast was 20.7% (Condition 3). Under these conditions, a spot-like luminance unevenness pattern was observed quite noticeably by visual observation.
  • the light source 61a is replaced with a green LED (non-coherent light source) and light from the LED light source is incident on the spatial light modulator 30, that is, the projection type video display device 10 shown in FIG.
  • the speckle contrast was 4.0% (Condition 4). Under these conditions, brightness unevenness (brightness unevenness) that could be visually recognized by naked eye observation did not occur.
  • condition 1 and condition 2 were much better than the result of condition 3, and were comparable to the measurement result of condition 4.
  • the problem of occurrence of the speckle practically, is an inherent problem that arises when using a coherent light source such as a laser beam, an apparatus using a non-coherent light source such as LED is necessary to consider There is no problem.
  • 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.
  • the optical element 50 in order to obscure the speckles, can also function as an optical member for shaping and adjusting the beam form of coherent light radiated from the irradiation unit 60. Therefore, the optical system can be reduced in size and simplified.
  • coherent light incident on each position of the hologram recording medium 55 generates an image 5 of the scattering plate 6 at the same position, and is superimposed on the image 5 to generate spatial light.
  • a modulator 30 is arranged. Therefore, the light diffracted by the hologram recording medium 55 can be used for image formation with high efficiency, and the use efficiency of light from the laser light sources 61a, 61b, 61c is excellent.
  • the spatial light modulator 30 In the basic mode, an example in which the spatial light modulator 30 is disposed at a position overlapping the illuminated region LZ has been described, but the spatial light modulator 30 may not be disposed at a position strictly overlapping the illuminated region LZ. .
  • the spatial light modulator 30 may be disposed closer to the optical element 50 than the illuminated region LZ, or may be disposed closer to the projection optical system 25 than the illuminated region LZ.
  • the optical element 50 and the spatial light modulator 30 only have to be arranged so that the coherent light that is diffracted by being incident on each incident region of the optical element 50 overlaps and illuminates the spatial light modulator 30.
  • the laser light sources 61a, 61b, 61c of the illumination device 60 may be independent laser light sources.
  • the illuminating device 60 serves as an incident-side optical system 70 that guides coherent light to the incident regions 55a, 55b, and 55c of the hologram recording medium 55 between the laser light sources 61a, 61b, and 61c and the hologram recording medium 55.
  • a convex lens 72 is provided.
  • the convex lens 72 With this convex lens 72, three coherent lights can be converged and irradiated onto the corresponding incident areas 55a, 55b, and 55c of the hologram recording medium 55, respectively. Even with such a configuration, an effect similar to that of the basic mode described above can be obtained.
  • a divergent light beam is used as the reference light Lr in place of the above-described convergent light beam in the exposure process when the hologram recording medium 55 is manufactured.
  • the incident side optical system 70 may be a diffractive optical element or a prism.
  • the illumination device 60 is replaced with the incident optical system 70 between the laser light sources 61 a, 61 b, 61 c and the corresponding incident areas 55 a, 55 b, 55 c of the hologram recording medium 55.
  • optical fibers 64a, 64b, and 64c that guide the coherent light to the corresponding incident regions 55a, 55b, and 55c of the hologram recording medium 55 may be provided.
  • the coherent light from the laser light source 61a is coupled by the optical coupling part CIa at the incident end of the optical fiber 64a and propagates through the optical fiber 64a, and the corresponding incident light of the hologram recording medium 55 from the optical coupling part COa at the outgoing end. The light is emitted to the region 55a.
  • the coherent light from the laser light source 61b is coupled by the optical coupling unit CIb, propagates through the optical fiber 64b, and is emitted from the optical coupling unit COb to the corresponding incident region 55b of the hologram recording medium 55.
  • Coherent light from the laser light source 61c is being coupled by the optical coupling unit CIc propagated through the optical fiber 64c, and is emitted from the light coupling portion COc the corresponding incident region 55c of the hologram recording medium 55.
  • the optical fibers 64a, 64b, and 64c may be physically bundled (bundled) at an intermediate portion.
  • each coherent light can be incident only on the corresponding incident region more reliably.
  • speckle can be made inconspicuous more reliably.
  • the laser light sources 61a, 61b, 61c can be arranged at arbitrary positions, restrictions on the arrangement of the optical system can be reduced, and the illumination device 40 can be downsized.
  • the lighting device 40 can be usefully used in various aspects.
  • the illumination device 40 can be used as simple illumination. In this case, brightness unevenness such as brightness unevenness and flickering can be made inconspicuous.
  • the illumination device 40 described above may be used as a scanner, for example, illumination for an image reading device.
  • the speckle generated on the target object can be made inconspicuous by arranging the target object to be scanned on the illuminated region LZ of the lighting device 40. As a result, it is possible to eliminate image correction means and the like that are conventionally required.
  • the illuminated area LZ by the illuminating device 40 may be a surface in the same manner as described above.
  • the illuminated area LZ by the illumination device 40 may be an elongated area or a linear area extending in one direction.
  • two-dimensional image information can be read by the illuminating device 40 incorporated in the scanner moving relative to the object along a direction orthogonal to the one direction.
  • the optical element 50 may include a plurality of hologram recording media 55-1, 55-2,... Arranged side by side so as not to overlap.
  • Each of the hologram recording media 55-1, 55-2,... Shown in FIG. 8 is formed in a strip shape, and is arranged side by side in the direction orthogonal to the longitudinal direction without any gap.
  • Each holographic recording medium 55-1 and 55-2, ... are positioned on the same virtual plane on each other.
  • Each hologram recording medium 55-1, 55-2,... Has an image 5 of the scattering plate 6 on the illuminated areas LZ-1, LZ-2,. Generate, in other words, illuminate the illuminated areas LZ-1, LZ-2,... With coherent light.
  • Each of the illuminated areas LZ-1, LZ-2,... Is formed as an elongated area or linear area extending in one direction, and is arranged side by side without a gap in a direction perpendicular to the longitudinal direction. Yes. Further, the illuminated areas LZ-1, LZ-2,... Are located on the same virtual plane.
  • the illuminated areas LZ-1, LZ-2,... May be illuminated as follows.
  • the irradiation device 60 optically transmits each coherent light to a corresponding incident point among incident points IP1 to IP3 along the longitudinal direction (the one direction) of the first hologram recording medium 55-1.
  • the first hologram recording medium 55-1 of the element 50 is irradiated with the coherent light.
  • the coherent light incident on each position of the first hologram recording medium 55-1 is superimposed on the first illumination area LZ-1 to reproduce the image 5 of the linear or elongated scattering plate 6, and the first One illumination region LZ-1 is simultaneously illuminated with coherent light.
  • the irradiation device 60 changes the direction of the laser array 62, for example, to change the three incident points on the second hologram recording medium 55-2 adjacent to the first hologram recording medium 55-1. Then, instead of the first illuminated area LZ-1, the second illuminated area LZ-2 adjacent to the first illuminated area LZ-1 is illuminated with the coherent light. Thereafter, three incident points on each hologram recording medium are sequentially irradiated with coherent light, and the illuminated area corresponding to the hologram recording medium is illuminated with the coherent light. According to such a method, it is possible to read two-dimensional image information without moving the illumination device. In FIG. 8, only the reproduction light Lb from the incident point IP2 is shown for clarity of explanation.
  • speckle can be effectively made inconspicuous.
  • this effect is mainly due to the lighting device 40.
  • this lighting device 40 is combined with various known spatial light modulators, projection optical systems, screens, etc., speckles can be effectively made inconspicuous.
  • 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.
  • the hologram recording medium 55 is manufactured by the interference exposure method using the planar scattering plate 6 having a shape corresponding to the incident surface of the spatial light modulator 30 .
  • the hologram recording medium 55 may be manufactured by an interference exposure method using a scattering plate having a certain pattern. In this case, the image of the scattering plate having a certain pattern is reproduced by the hologram recording medium 55. In other words, the optical element 50 (hologram recording medium 55) illuminates the illuminated area LZ having a certain pattern.
  • the spatial light modulator 30 and the projection optical system 25 are also omitted from the basic form described above, and the screen 15 is disposed on the screen 15 by overlapping with the illuminated region LZ. Any pattern recorded on the hologram recording medium 55 can be displayed. Also in this display device, the non-coherent coherent light from each of the laser light sources 61a, 61b, 61c is incident only on the corresponding incident area of the hologram recording medium 55, thereby making speckles on the screen 15 inconspicuous. be able to.
  • FIG. 9 discloses an example of such an example.
  • the optical element 50 includes first to third hologram recording media 55-1, 55-2, and 55-3.
  • the first to third hologram recording media 55-1, 55-2, and 55-3 are arranged on surfaces parallel to the incident surface of the optical element 50 so as not to overlap each other.
  • Each of the hologram recording media 55-1, 55-2, 55-3 can reproduce the image 5 having the outline of the arrow, in other words, the illuminated areas LZ-1, LZ- having the outline of the arrow. 2 and LZ-3 can be illuminated with coherent light.
  • the first to third illuminated areas LZ-1, LZ-2, and LZ-3 corresponding to the hologram recording media 55-1, 55-2, and 55-3 overlap each other on the same virtual plane.
  • each illumination zone LZ-1, LZ-2, LZ-3 in the direction all the same as indicated by the arrows forming each illumination zone LZ-1, LZ-2, LZ-3, the first to third illumination zone LZ-1 along this direction, LZ-2 and LZ-3 are positioned in order.
  • the coherent lights from the irradiation device 60 are simultaneously incident on the corresponding incident points IP1-1 to IP3-1 on the first hologram recording medium 55-1, the first rearmost position is placed.
  • the illuminated area LZ-1 is illuminated.
  • each coherent light from the irradiation device 60 is incident on a corresponding incident point IP ⁇ b> 1-2 on the second hologram recording medium 55-2.
  • IP3-2 are incident on IP3-2 at the same time, and the second illuminated area LZ-2 located in the middle is illuminated.
  • the respective coherent lights from the irradiation device 60 are simultaneously incident on the corresponding incident points IP1-3 to IP3-3 on the third hologram recording medium 55-3, the third illuminated object positioned at the foremost position is provided.
  • Area LZ-3 is illuminated.
  • FIG. 9 only the reproduction light Lb from the incident points IP2-1, IP2-2, and IP2-3 is shown for clarity of explanation.
  • the irradiation apparatus 60 irradiates the coherent light to the three incident points located on the straight line on the plate surface of the hologram recording medium 55 at the same time, but is not limited thereto.
  • the incident points IP 1 to IP 3 of the coherent light from the irradiation device 60 to the hologram recording medium 55 may be at arbitrary positions on the plate surface of the hologram recording medium 55. That is, the incident points IP 1 to IP 3 may be two-dimensionally positioned on the plate surface of the hologram recording medium 55.
  • the description of the reproduction light Lb from the incident point IP2 is omitted for clarity of explanation.
  • FIG. 10 the description of the reproduction light Lb from the incident point IP2 is omitted for clarity of explanation.
  • the laser array 62 preferably has more laser light sources.
  • the laser array 62 may have laser light sources in a matrix, and these laser light sources may emit coherent light to a plurality of incident points positioned in a matrix on the plate surface of the hologram recording medium 55.
  • the laser light sources 61a, 61b, 61c of the irradiation device 60 have been described on the premise that they oscillate laser light shaped as a linear light beam, the present invention is not limited to this.
  • the coherent light irradiated to each position of the optical element 50 is shaped by the optical element 50 into a light beam that enters the entire illuminated area LZ. Therefore, inconvenience does not occur even if the coherent light irradiated to the optical element 50 from the light sources 61a, 61b, 61c of the irradiation device 60 is not accurately shaped. For this reason, the coherent light generated from the light sources 61a, 61b, and 61c may be diverging light.
  • the cross-sectional shape of the coherent light generated from the light sources 61a, 61b, and 61c may be an ellipse or the like instead of a circle.
  • the transverse mode of the coherent light generated from the light sources 61a, 61b, 61c may be a multimode.
  • the coherent light is incident on a region having a certain area instead of a point when entering the hologram recording medium 55 of the optical element 50.
  • the light diffracted by the hologram recording medium 55 and incident on each position of the illuminated region LZ is multiplexed with an angle rather than the basic form. Speckle can be made more inconspicuous by such multiplexing of angles.
  • the irradiation device 60 causes the coherent light to enter the optical element 50 so as to follow the optical path of one light beam included in the divergent light beam, but is not limited thereto.
  • the irradiation device 60 may not include the concave lens 71.
  • coherent light from each of the laser light sources 61a, 61b, 61c is directly incident only on the corresponding incident region of the hologram recording medium 55 of the optical element 50. That is, the irradiation device 60 causes the coherent light to be incident on the optical element 50 so as to follow the optical path of the light beam constituting the parallel light flux.
  • a parallel light beam is used as the reference light Lr instead of the above-described convergent light beam in the exposure process when the hologram recording medium 55 is manufactured.
  • Such a hologram recording medium 55 can be produced and duplicated more easily.
  • the irradiation device 60 may include a plurality of light sources that generate coherent light in different wavelength ranges. Even in this case, the irradiation device 60 needs to include a plurality of light sources each generating coherent light having the same wavelength and no interference with each wavelength region. According to this example, a color that is difficult to display with a single laser beam can be generated by additive color mixing, and the illuminated area LZ can be illuminated with that color. Further, in this case, in the projection device 20 or the transmissive image display device 10, the spatial light modulator 30 includes, for example, a color filter, and a modulated image can be formed for each coherent light in each wavelength region. Makes it possible to display images in a plurality of colors.
  • 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.
  • the irradiation device 60 includes a light source that generates coherent light in a wavelength region corresponding to red light, and a light source that generates coherent light in a wavelength region corresponding to green light. In the case where it includes a light source that generates coherent light in a wavelength range corresponding to blue light, it is possible to display an image in full color.
  • the hologram recording medium 55 included in the optical element 50 has wavelength selectivity. Therefore, when the irradiation device 60 includes light sources having different wavelength ranges, the hologram recording medium 55 includes the hologram elements corresponding to the wavelength ranges of the coherent light generated by the respective light sources in a stacked state. You may make it.
  • the hologram element for coherent light in each wavelength region is obtained by using, for example, the coherent light in the corresponding wavelength region as exposure light (reference light Lr and object light Lo) in the method already described with reference to FIGS. It can be made by using light.
  • a single holographic recording medium 55 may be a plurality of wavelength regions of light to be diffracted, respectively.
  • the optical element 50 may include a plurality of hologram recording media 55.
  • the optical element 50 shown in FIG. 1 may include three hologram recording media corresponding to the incident areas 55a, 55b, and 55c, and each coherent light may enter only the corresponding hologram recording medium.
  • the optical element 50 may include a volume hologram that is recorded using a photosensitive medium including a silver salt material.
  • the optical element 50 may include a reflection type volume hologram recording medium or a relief type (emboss type) hologram recording medium.
  • a relief (embossed) hologram is recorded with hologram interference fringes due to the uneven structure on the surface.
  • the relief type hologram scattering by irregular structure on the surface, in addition to the loss of light quantity, may become an unintended new speckle generating factors, it is preferable for volume hologram in this respect.
  • the volume hologram since hologram interference fringes are recorded as a refractive index modulation pattern (refractive index distribution) inside the medium, it is not affected by scattering due to the uneven structure on the surface.
  • the hologram recording medium 55 is preferably a volume hologram using a photopolymer.
  • a so-called Fresnel type hologram recording medium is produced.
  • a Fourier transform type hologram recording medium obtained by performing recording using a lens may be produced. Absent.
  • a lens may also be used during image reproduction.
  • the striped pattern (refractive index modulation pattern or concave / convex pattern) to be formed on the hologram recording medium 55 does not use the actual object light Lo and reference light Lr, but the planned wavelength and incident direction of the reproduction illumination light La. In addition, it may be designed using a computer based on the shape and position of the image to be reproduced.
  • the hologram recording medium 55 obtained in this way is also called a computer-generated hologram.
  • the hologram recording medium 55 as a computer-generated hologram corresponds to each coherent light in each wavelength range.
  • the coherent light in each wavelength region may be diffracted in the corresponding region to reproduce an image.
  • the optical element 50 includes the hologram recording medium 55 that expands the coherent light irradiated to each position and illuminates the entire illuminated area LZ using the expanded coherent light.
  • the optical element 50 changes or diffuses the traveling direction of the coherent light irradiated to each position instead of the hologram recording medium 55 or in addition to the hologram recording medium 55, and diffuses the entire illuminated area LZ with coherent light.
  • the irradiation device 60 irradiates the lens array or the diffusion plate with coherent light, and the coherent light incident on each position of the lens array or the diffusion plate from the irradiation device 60 respectively.
  • the irradiation device 60 and the optical element 50 By configuring the irradiation device 60 and the optical element 50 so that the traveling direction is changed by the lens array or the diffusion plate to illuminate at least the illuminated area LZ, the speckle can be effectively inconspicuous. .
  • the irradiation device 60 is configured to irradiate the coherent light on each position aligned in the one-dimensional direction on the optical element 50, and the hologram recording medium 55, the lens array, or the diffusion plate of the optical element 50
  • An example in which the coherent light irradiated to each position is configured to diffuse in a two-dimensional direction and the illumination device 40 illuminates the two-dimensional illuminated region LZ by this is shown.
  • the present invention is not limited to such an example.
  • the irradiation device 60 is configured to irradiate each position on the optical element 50 that is two-dimensionally arranged with coherent light.
  • the hologram recording medium 55, the lens array, or the diffusing plate of the optical element 50 is configured to diffuse the coherent light irradiated to each position in a two-dimensional direction.
  • the illumination area LZ may be illuminated (aspect already described with reference to FIG. 10).
  • the irradiation device 60 is configured to irradiate each position on the optical element 50 that is aligned in the one-dimensional direction, and the hologram recording medium 55 and the lens of the optical element 50.
  • the array or the diffusion plate may be configured to diffuse the coherent light irradiated to each position in a one-dimensional direction, and thereby the illumination device 40 may illuminate the one-dimensional illuminated area LZ.
  • the arrangement direction of the positions where the coherent light is irradiated by the irradiation device 60 and the diffusion direction of the hologram recording medium 55, the lens array, or the diffusion plate of the optical element may be parallel.
  • the irradiation device 60 is configured to irradiate the coherent light on each position arranged in the one-dimensional direction on the optical element 50 or each position arranged two-dimensionally, and the hologram recording medium 55 of the optical element 50,
  • the lens array or the diffusion plate may be configured to diffuse the coherent light irradiated to each position in a one-dimensional direction.
  • the optical element 50 has a plurality of hologram recording media 55, lens arrays or diffusion plates, and the illuminated areas LZ corresponding to the hologram recording media 55, lens arrays or diffusion plates are sequentially arranged.
  • the illumination device 40 may illuminate a two-dimensional area by illuminating. At this time, each of the illumination zone LZ is in one of such speeds the human eye is simultaneously illuminated, can be recognized may be going is illuminated sequentially, or the even the human eye are illuminated in sequence It may be illuminated sequentially at such a slow speed.
  • the incident side optical system 70 may include an imaging optical system 80.
  • FIG. 11 is a diagram for explaining a modification of the incident-side optical system 70, and is a diagram illustrating a schematic configuration of an illumination device, a projection device, and a projection type video display device.
  • the incident-side optical system 70 the laser light sources (coherent light source) 61a, 61b, the corresponding incident region 55a of the optical element 50 the image of 61c, 55b, the imaging optical system for focusing the 55c 80. That is, the image of the laser light source 61a is formed on the corresponding incident area 55a, the image of the laser light source 61b is formed on the corresponding incident area 55b, and the image of the laser light source 61c is formed on the corresponding incident area 55c.
  • the image plane 61X of the light source is, for example, a plane parallel to the incident surface of the optical element 50, and is located in the optical element 50.
  • the imaging optical system 80 has a convex lens 81 and a concave lens 82, and the convex lens 81 is disposed on the side close to the laser light sources 61a, 61b, 61c.
  • the coherent light from the laser light sources 61a, 61b, and 61c passes through the convex lens 81 and the concave lens 82 in this order, and enters the optical element 50.
  • the convex lens 81 forms images of the laser light sources 61a, 61b, and 61c on the corresponding incident areas 55a, 55b, and 55c of the optical element 50.
  • the concave lens 82 spreads each coherent light beam from the laser light sources 61a, 61b, 61c of the dense laser array 62, as in the basic form of FIG. That is, the concave lens 82 increases the interval between the coherent light beams in order to reduce speckle.
  • FIG. 12 is a diagram for explaining another modified example of the incident-side optical system 70, and is a diagram showing a schematic configuration of an illumination device, a projection device, and a projection type video display device.
  • the imaging optical system 80 has a concave lens 83 and convex lens 84, the laser light source 61a, 61b, the point that the concave lens 83 on the side are arranged close to 61c, Different from the example of FIG.
  • the imaging optical system 80 forms images of the laser light sources 61 a, 61 b, 61 c on the corresponding incident areas 55 a, 55 b, 55 c of the optical element 50.
  • the coherent light which is parallel light from the laser light sources 61a, 61b, 61c, is diverged by the concave lens 83, and is then made parallel light again by the convex lens 84.
  • the convex lens 84 forms images of the laser light sources 61a, 61b, and 61c on the corresponding incident areas 55a, 55b, and 55c of the optical element 50. That is, according to this configuration, each coherent light can be efficiently separated and incident only on the corresponding incident regions 55a, 55b, and 55c of the optical element 50. As in the example of FIG. 11, different speckle patterns can be generated on the screen 15 more reliably.
  • the image plane 61X of the light source is, for example, a plane parallel to the incident surface of the optical element 50 and is located in the optical element 50.
  • the imaging optical system 80 may be configured using one lens or three or more lenses.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Projection Apparatus (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)

Abstract

L'invention concerne un dispositif d'éclairage qui permet de réduire l'effet de chatoiement. Ledit dispositif d'éclairage (40) comprend un élément optique (50) capable de diffuser une lumière cohérente, et une pluralité de sources de lumière cohérente (61a, 61b, 61c) pour émettre des lumières cohérentes ayant la même longueur d'onde. L'élément optique comporte une pluralité de régions d'incidence (55a, 55b, 55c). La lumière cohérente de chaque source de lumière cohérente est incidente sur la région d'incidence correspondante de l'élément optique. Les lumières cohérentes incidentes sur les régions d'incidence de l'élément optique sont diffusées, et éclairent des régions qui se chevauchent au moins partiellement.
PCT/JP2012/060042 2011-04-15 2012-04-12 Dispositif d'éclairage, dispositif de projection, et dispositif d'affichage d'images de type projection WO2012141254A1 (fr)

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JP2017090816A (ja) * 2015-11-16 2017-05-25 セイコーエプソン株式会社 照明装置及びプロジェクター
EP3421868A4 (fr) * 2016-02-24 2019-08-21 Dai Nippon Printing Co., Ltd. Dispositif d'éclairage
US10690932B2 (en) 2016-02-24 2020-06-23 Dai Nippon Printing Co., Ltd. Lighting device
CN110431482A (zh) * 2017-03-23 2019-11-08 Nec显示器解决方案株式会社 光源装置、投影仪和散斑减少方法
US10928643B2 (en) 2017-03-23 2021-02-23 Nec Display Solutions, Ltd. Light source device including laser light sources, projector, and speckle reduction method for forming light by mixing diffused lights emitted from laser light source groups
CN110431482B (zh) * 2017-03-23 2022-01-04 夏普Nec显示器解决方案株式会社 光源装置、投影仪和散斑减少方法

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