# US 9,039,188 B2 · Illumination device, projection device, and projection-type image display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,188 B2 - Document ID: US9039188B2 - Status: Granted - Kind: B2 - Application number: 13/821,754 - Filed: 2011-09-08 - Published: 2013-07-04 - Granted: 2015-05-26 - Earliest claimed: 2010-09-08 - Assignees: Dai Nippon Printing Co., Ltd. - Applicants: Tomoe Takanokura; Kazutoshi Ishida; Makio Kurashige; Yasuyuki Ooyagi - Inventors: Tomoe Takanokura; Kazutoshi Ishida; Makio Kurashige; Yasuyuki Ooyagi - Web page: https://patentgrep.com/patent/US9039188B2 ## CPC - G02B 27/0944: {Diffractive optical elements, e.g. gratings, holograms (gratings per se G02B5/18; holograms used as optical elements per se G02B5/32)} - G02B 5/1842: {Gratings for image generation (G02B5/1847 takes precedence)} - G02B 5/32: Holograms used as optical elements - G02B 26/105: {with one or more pivoting mirrors or galvano-mirrors (G02B26/101 takes precedence)} - G02B 27/48: Laser speckle optics - G03B 21/14: Details - G03B 21/2033: {LED or laser light sources} - G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)} - G03B 21/208: {Homogenising, shaping of the illumination light} - G03B 21/28: Reflectors in projection beam {(in illumination beam G03B21/2066)} - G03B 33/06: by additive-colour projection apparatus - G03B 33/12: using beam-splitting or beam-combining systems, e.g. dichroic mirrors - G03H 1/02: Details {of features involved during the holographic process; Replication of holograms without interference recording} - G03H 1/32: Systems for obtaining speckle elimination - H04N 5/89: using holographic recording (H04N5/91 takes precedence) - H04N 9/3111: {for displaying the colours sequentially, e.g. by using sequentially activated light sources (sequential projection in colour photography G03B33/08)} - H04N 9/3129: {scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161)} - H04N 9/3161: {using laser light sources (using laser beams scanning the display screen H04N9/3129)} - G03H 2001/2292: {Using scanning means} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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 (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00}) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Provided is an illumination device which illuminates an illuminated zone with a plurality of coherent light beams having mutually different wavelength ranges, so that it is possible to allow speckles to be inconspicuous. A illumination device is configured to include an optical element including a hologram recording medium and an irradiation device which illuminates the optical element with a plurality of coherent light beams having mutually different wavelength ranges so as to allow a first and second coherent light beams having different wavelength ranges to scan the hologram recording medium of the optical element. The first coherent light beams incident on respective positions of the hologram recording medium are allowed to reproduce an image superimposed on an illuminated zone, and the second coherent light beams incident on the respective positions of the hologram recording medium are allowed to reproduce an image superimposed on the illuminated zone. ## Claims ### Claim 1 An illumination device comprising: an optical element including a hologram recording medium which records an image of a scattering plate and diffracts a first coherent light beam having a first wavelength range and a second coherent light beam having a second wavelength range which is different from the first wavelength range so as to reproduce the image of the scattering plate; and an irradiation device configured to irradiate the optical element with light beams having different wavelength ranges so as to allow the first coherent light beam and the second coherent light beam to scan the hologram recording medium, wherein the irradiation device and the optical element are arranged such that the first coherent light beams incident from the irradiation device on respective positions of the hologram recording medium are diffracted by the hologram recording medium and reproduce the images of the scattering plate superimposed on a zone, and the second coherent light beams incident from the irradiation device on respective positions of the hologram recording medium are diffracted by the hologram recording medium and reproduce the images of the scattering plate superimposed on the zone so as to illuminate the zone with reproduction light beams which reproduce the images of the scattering plate. ### Claim 2 (depends on 1) The illumination device according to claim 1, wherein the hologram recording medium is configured to diffract a third coherent light beam having a third wavelength range different from both of the first wavelength range and the second wavelength range so as to reproduce the image of the scattering plate, wherein the coherent light beams having different wavelength ranges irradiated from the irradiation device further includes the third coherent light beam, wherein the irradiation device and the optical element are arranged such that the third coherent light beams incident from the irradiation device on respective positions of the hologram recording medium are diffracted by the hologram recording medium and reproduce the images of the scattering plate superimposed on the zone, and wherein 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. ### Claim 3 (depends on 1) The illumination device according to claim 1, wherein the hologram recording medium includes a plurality of laminated hologram elements which are provided corresponding to the coherent light beams having the respective wavelength ranges. ### Claim 4 (depends on 1) The illumination device according to claim 1, wherein the coherent light beams having different wavelength ranges are irradiated in a same optical path from the irradiation device on the optical element. ### Claim 5 (depends on 1) The illumination device according to claim 1, wherein the irradiation device includes a light source system which generates a combined light beam formed by combining the coherent light beams having different wavelength ranges and a scan device configured to change a traveling direction of the combined light beam from the light source system to allow the combined light beam to scan the optical element. ### Claim 6 (depends on 5) The illumination device according to claim 5, wherein the light source system includes light sources which generate the coherent light beams having respective wavelength ranges and a combining device which combines the coherent light beams from the light sources. ### Claim 7 (depends on 1) The illumination device according to claim 1, wherein the irradiation device irradiates the optical element with the coherent light beams having different wavelength ranges in a time division manner. ### Claim 8 (depends on 1) The illumination device according to claim 1, wherein the image of the scattering plate was recorded in the hologram recording medium by using a reference light beam which was irradiated along a given path, and the irradiation device is configured to irradiate the hologram recording medium with the coherent light beams having different wavelength ranges such that the incidence directions of the first and second coherent light beams on respective positions of the hologram recording medium are along a traveling direction of the reference light beam. ### Claim 9 (depends on 1) A projection device comprising: the illumination device according to claim 1; and a spatial light modulator positioned at a position which overlaps the zone on which the image of the scattering plate is to be reproduced and superimposed. ### Claim 10 (depends on 9) The projection device according to claim 9, further comprising a projection optical system configured to project a modulation image obtained on the spatial light modulator on a screen. ### Claim 11 (depends on 9) A projection-type image display device comprising: the projection device according to claim 9; and a screen on which a modulation image obtained on the spatial light modulator is projected. ### Claim 12 (depends on 1) A projection-type image display device comprising: the illumination device according to claim 1; a screen positioned at a position which overlaps the zone on which the image of the scattering plate is to be reproduced and superimposed.