# US 10,768,517 B2 · 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 10,768,517 B2 - Document ID: US10768517B2 - Status: Granted - Kind: B2 - Application number: 15/556,239 - Filed: 2016-02-18 - Published: 2018-08-23 - Granted: 2020-09-08 - Earliest claimed: 2015-03-09 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Koichi Akiyama; Akihiro Kashiwagi; Chigusa Takagi - Web page: https://patentgrep.com/patent/US10768517B2 ## CPC - 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 21/006: {using LCD's} - G03B 21/2066: {Reflectors in illumination beam (in projection beam G03B21/28)} - G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)} - G03B 21/208: {Homogenising, shaping of the illumination light} - G03B 21/28: Reflectors in projection beam {(in illumination beam G03B21/2066)} - H04N 9/3105: {for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators (simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10)} - H04N 9/3158: {for controlling the spectrum} - H04N 9/3161: {using laser light sources (using laser beams scanning the display screen H04N9/3129)} - H04N 9/3164: {using multiple light sources} - G03B 21/2013: {Plural light sources} - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A light source device includes: a light emission element; a condensing optical system on which a first component of light emitted from the light emission element is incident; an optical element on which the first component transmitted through the condensing optical system is incident; and a pickup optical system on which the first component having travelled via the optical element is incident. At least one of the condensing optical system and the pickup optical system includes a first lens formed of quartz. ## Claims ### Claim 1 A light source device comprising: a light emission element; a polarization separation element on which a light emitted from the light emission element is incident, and that separates the light into a first component of light polarized in a first direction and a second component of light polarized in a second direction perpendicular to the first direction; a phase difference element on which the first component of light is incident, and that converts the first component of light to a circularly polarized light; a condensing optical system on which the circularly polarized light is incident; an optical element on which the circularly polarized light transmitted through the condensing optical system is incident, wherein the polarization separation element is provided on a light path between the light emission element and the condensing optical system, the phase difference element is provided on a light path between the polarization separation element and the condensing optical system, the optical element includes a reflection surface from which the circularly polarized light is reflected, the circularly polarized light reflected from the reflection surface is incident on the condensing optical system, the circularly polarized light transmitted through the condensing optical system is incident on the phase difference element, and that is converted to a third component of light polarized in the second direction, the third component of light is incident on the polarization separation element, the condensing optical system includes a first lens and a second lens, the first lens being formed of quartz, the first lens is disposed at a position closest to the phase difference element in the condensing optical system, the first lens has an aspheric surface with a negative conic constant on a side of the phase difference element, the first lens has a curve surface with a radius of curvature of 1000 mm or more or a planar surface on a side facing away from the phase difference element, and an absolute value of a curvature of the aspheric surface is greater than an absolute value of a curvature of the curve surface or the planar surface. ### Claim 2 (depends on 1) The light source device according to claim 1, wherein the condensing optical system further includes a fourth lens, the fourth lens is disposed between the first lens and the second lens, and the fourth lens is formed of quartz. ### Claim 3 (depends on 1) A projector comprising: the light source device according to claim 1; a light modulation device that modulates light emitted from the light source device, in accordance with image information, to form image light; and a projection optical system that projects the image light. ### Claim 4 A light source device comprising: a light emission element; a polarization separation element on which a light emitted from the light emission element is incident, and that separates the light into a first component of light polarized in a first direction and a second component of light polarized in a second direction perpendicular to the first direction; a phase difference element on which the first component of light is incident, and that converts the first component of light to a circularly polarized light; a condensing optical system on which the circularly polarized light is incident; an optical element on which the circularly polarized light transmitted through the condensing optical system is incident, wherein the polarization separation element is provided on a light path between the light emission element and the condensing optical system, the phase difference element is provided on a light path between the polarization separation element and the condensing optical system, the optical element includes a reflection surface from which the circularly polarized light is reflected, the circularly polarized light reflected from the reflection surface is incident on the condensing optical system, the circularly polarized light transmitted through the condensing optical system is incident on the phase difference element, and that is converted to a third component of light polarized in the second direction, the third component of light is incident on the polarization separation element, the condensing optical system includes a first lens and a third lens, the first lens being formed of quartz, the first lens is disposed at a position closest to the optical element in the condensing optical system, the third lens is disposed at a position closest to the base difference element in the condensing optical system, and a photoelastic constant of the third lens is less than a photoelastic, constant of the first lens. ### Claim 5 (depends on 4) The light source device according to claim 4, wherein the third lens has an aspheric surface with a negative conic constant on a side of the phase difference element. ### Claim 6 (depends on 4) The light source device according to claim 4, wherein the condensing optical system further includes a fifth lens, the fifth lens is disposed between the first lens and the third lens, and the fifth lens is formed of quartz. ### Claim 7 (depends on 4) A projector comprising: the light source device according to claim 4; a light modulation device that modulates light emitted from the light source device, in accordance with image information, to form image light; and a projection optical system that projects the image light. ### Claim 8 A light source device comprising: a light emission element; a polarization separation element on which a light emitted from the light emission element is incident, and that separates the light into a first component of light polarized in a first direction and a second component of light polarized in a second direction perpendicular to the first direction; a phase difference element on which the first component of light is incident, and that converts the first component of light to a circularly polarized light; a condensing optical system on which the circularly polarized light is incident; an optical element on which the circularly polarized light transmitted through the condensing optical system is incident, wherein the polarization separation element is provided on a light path between the light emission element and the condensing optical system, the phase difference element is provided on a light path between the polarization separation element and the condensing optical system, the optical element includes a reflection surface from which the circularly polarized light is reflected, the circularly polarized light reflected from the reflection surface is incident on the condensing optical system, the circularly polarized light transmitted through the condensing optical system is incident on the phase difference element, and that is converted to a third component of light polarized in the second direction, the third component of light is incident on the polarization separation element, the condensing optical system includes a first lens and a second lens, the first lens being formed of quartz, the first lens is disposed at a position closest to the phase difference element in the condensing optical system, the second lens is disposed at a position closest to the optical element in the condensing optical system, the second lens is formed of quartz, the second lens has a curve surface with a radius of curvature of 1000 mm or more or a planar surface on a side of the optical element, the second lens has a spherical surface on a side facing away from the optical element, and an absolute value of a curvature of the spherical surface is greater than an absolute value of a curvature of the curve surface or the planar surface. ### Claim 9 (depends on 8) The light source device according to claim 8, wherein the condensing optical system further includes a fourth lens, the fourth lens is disposed between the first lens and the second lens, and the fourth lens is formed of quartz. ### Claim 10 A light source device comprising: a light emission element; a polarization separation element on which a light emitted from the light emission element is incident, and that separates the light into a first component of light polarized in a first direction and a second component of light polarized in a second direction perpendicular to the first direction; a phase difference element on which the first component of light is incident, and that converts the first component of light to a circularly polarized light; a condensing optical system on which the circularly polarized light is incident; an optical element on which the circularly polarized light transmitted through the condensing optical system is incident, wherein the polarization separation element is provided on a light path between the light emission element and the condensing optical system, the phase difference element is provided on a light path between the polarization separation element and the condensing optical system, the optical element includes a reflection surface from which the circularly polarized light is reflected, the circularly polarized light reflected from the reflection surface is incident on the condensing optical system, the circularly polarized light transmitted through the condensing optical system is incident on the phase difference element, and that is converted to a third component of light polarized in the second direction, the third component of light is incident on the polarization separation element, the condensing optical system includes a first lens and a third lens, the first lens being formed of quartz, the first lens is disposed at a position closest to the optical element in the condensing optical system, the first lens has a curve surface with a radius of curvature of 1000 mm or more or a planar surface on a side of the optical element, the first lens has a spherical surface on a side facing away from the optical element, and an absolute value of a curvature of the spherical surface is greater than an absolute value of a curvature of the curve surface or the planar surface. ### Claim 11 (depends on 10) The light source device according to claim 10, wherein the condensing optical system further includes a fifth lens, the fifth lens is disposed between the first lens and the third lens, and the fifth lens is formed of quartz. ### Claim 12 (depends on 8) A projector comprising: the light source device according to claim 8; a light modulation device that modulates light emitted from the light source device, in accordance with image information, to form image light; and a projection optical system that projects the image light. ### Claim 13 (depends on 10) A projector comprising: the light source device according to claim 10; a light modulation device that modulates light emitted from the light source device, in accordance with image information, to form image light; and a projection optical system that projects the image light.