# US 2020/0401032 A1 · Light source device and projector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0401032 A1 - Document ID: US20200401032A1 - Status: Published application - Kind: A1 - Application number: 16/903,761 - Filed: 2020-06-17 - Published: 2020-12-24 - Earliest claimed: 2019-06-18 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Koichi AKIYAMA - Web page: https://patentgrep.com/patent/US20200401032A1 ## CPC - G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)} - G03B 21/2013: {Plural light sources} - G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)} - G03B 21/208: {Homogenising, shaping of the illumination light} - G03B 21/006: {using LCD's} - G03B 21/204: {using secondary light emission, e.g. luminescence or fluorescence (using different colours G03B33/00; if related to video signals H04N9/3197)} - 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) ## Abstract A light source device of the present disclosure includes a light emitting device that outputs a first light having a first wavelength in a first polarization direction, a first optical element having a first area and a second area, a second optical element into which the first light reflected by the first area is entered, converting the first light into a circularly-polarized second light having the first wavelength, and a diffuser element into which the second light is entered. The second light entering the second optical element is converted into a third light having the first wavelength in a second polarization direction, the third light is transmitted through the first area, the second light is transmitted through the second area, and a fourth light output from the diffuser element and entered into the first area and the second area is transmitted through the first area and the second area. ## Claims ### Claim 1 A light source device comprising: a light emitting device that outputs a first light having a first wavelength in a first polarization direction; a first optical element having a first area that reflects the first light and a second area different from the first area; a second optical element into which the first light reflected by the first area of the first optical element is entered, converting the first light into a circularly-polarized second light having the first wavelength; and a diffuser element into which the second light output from the second optical element is entered, wherein the second light reflected by the diffuser element and entered into the second optical element is converted into a third light having the first wavelength in a second polarization direction by the second optical element, the third light output from the second optical element and entering the first area of the first optical element is transmitted in the first area of the first optical element, the second light reflected by the diffuser element and entered into the second area of the first optical element is transmitted in the second area of the first optical element, and a fourth light output from the diffuser element and entered into the first area and the second area of the first optical element and having a second wavelength is transmitted in the first area and the second area of the first optical element. ### Claim 2 (depends on 1) The light source device according to claim 1, wherein in the first optical element, the first area is provided at a center of the first optical element and the second area is provided around the first area. ### Claim 3 (depends on 1) The light source device according to claim 1, wherein the second optical element is placed to face the first area at one side of the first optical element. ### Claim 4 (depends on 1) The light source device according to claim 1, wherein the second optical element is formed using quartz crystal. ### Claim 5 (depends on 1) The light source device according to claim 1, further comprising a third optical element into which the third light output from the first area of the first optical element is entered, wherein the third optical element converts the third light into a circularly-polarized fifth light having the first wavelength. ### Claim 6 (depends on 5) The light source device according to claim 5, wherein the third optical element is placed to face the first area at another side of the first optical element. ### Claim 7 (depends on 5) The light source device according to claim 5, wherein the third optical element is formed using quartz crystal. ### Claim 8 (depends on 1) The light source device according to claim 1, wherein a diffuse reflection portion that diffusely reflects a part of the second light is provided at a light incident side of the diffuser element. ### Claim 9 (depends on 8) The light source device according to claim 8, wherein the diffuse reflection portion has an optical film that reflects the part of the second light and transmits the rest of the second light. ### Claim 10 (depends on 1) The light source device according to claim 1, further comprising a luminous flux width compression unit provided between the light emitting device and the first optical element and compressing a luminous flux width of the first light output from the light emitting device. ### Claim 11 (depends on 1) A projector comprising: the light source device according to claim 1; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 12 (depends on 2) A projector comprising: the light source device according to claim 2; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 13 (depends on 3) A projector comprising: the light source device according to claim 3; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 14 (depends on 4) A projector comprising: the light source device according to claim 4; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 15 (depends on 5) A projector comprising: the light source device according to claim 5; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 16 (depends on 6) A projector comprising: the light source device according to claim 6; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 17 (depends on 7) A projector comprising: the light source device according to claim 7; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 18 (depends on 8) A projector comprising: the light source device according to claim 8; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 19 (depends on 9) A projector comprising: the light source device according to claim 9; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light. ### Claim 20 (depends on 10) A projector comprising: the light source device according to claim 10; a light modulation device that modulates the light output from the light source device according to image information and forms an image light; and a projection optical device that projects the image light.