# US 12,216,294 B2 · Optical element, projection optical apparatus, and projector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,294 B2 - Document ID: US12216294B2 - Status: Granted - Kind: B2 - Application number: 17/708,613 - Filed: 2022-03-30 - Published: 2022-10-06 - Granted: 2025-02-04 - Earliest claimed: 2021-03-31 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Kaho Watanabe - Web page: https://patentgrep.com/patent/US12216294B2 ## CPC - G02B 1/04: made of organic materials, e.g. plastics (G02B1/08 takes precedence) - G02B 3/04: with continuous faces that are rotationally symmetrical but deviate from a true sphere {, e.g. so called "aspheric" lenses} - G02B 1/041: {Lenses} - G02B 7/021: {for more than one lens} - G02B 7/025: {using glue} - G02B 27/149: {using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes} - G03B 21/14: Details - G02B 27/0927: {Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat} - 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) ## Abstract An optical element includes a first light-transmissive member made of a first resin and having a first surface having an aspheric shape and a first joint surface provided on the side opposite from the first surface, a second light-transmissive member made of a material different from the material of the first light-transmissive member and having a second joint surface, and a first joining member and a second joining member that join the first joint surface and the second joint surface to each other. The first joining member is made of a silicone adhesive and disposed in the smaller one of effective diameter regions of the first light-transmissive member and the second light-transmissive member. The second joining member is made of an adhesive having adhesiveness higher than the adhesiveness of the silicone adhesive and is disposed outside the first joining member and outside the smaller effective diameter region. ## Claims ### Claim 1 An optical element comprising: a first light-transmissive member made of a first resin and having a first surface having an aspheric shape and a first joint surface provided on a side opposite from the first surface; a second light-transmissive member made of a material different from the material of the first light-transmissive member and having a second joint surface; and a first joining member and a second joining member that join the first joint surface and the second joint surface to each other, wherein the first joining member is made of a silicone adhesive and disposed in a smaller effective diameter region of the effective diameter region of the first light-transmissive member and the effective diameter region of the second light-transmissive member, and the second joining member is made of an adhesive having adhesiveness higher than the adhesiveness of the silicone adhesive and is disposed outside the first joining member and outside the smaller effective diameter region. ### Claim 2 (depends on 1) The optical element according to claim 1, further comprising a first spacer disposed between the first joint surface and the second joint surface. ### Claim 3 (depends on 2) The optical element according to claim 2, wherein the first spacer is disposed outside the first joining member. ### Claim 4 (depends on 2) The optical element according to claim 2, further comprising a second spacer disposed between the first joint surface and the second joint surface, wherein the first spacer is provided between the first joining member and the second joining member, and the second spacer is provided on a side facing an outer circumferential edge of the first joint surface with respect to the second joining member. ### Claim 5 (depends on 2) The optical element according to claim 2, wherein the first spacer has a cutout that causes a region inside the first spacer to communicate with a region outside the first spacer. ### Claim 6 (depends on 1) The optical element according to claim 1, wherein at least one of the first joint surface and the second joint surface has a groove provided between the first joining member and the second joining member, and the groove surrounds the first joining member. ### Claim 7 (depends on 1) The optical element according to claim 1, wherein at least one of the first joint surface and the second joint surface has a groove provided outside the first joining member, and the groove surrounds the second joining member. ### Claim 8 (depends on 1) The optical element according to claim 1, wherein the second light-transmissive member is made of glass. ### Claim 9 (depends on 8) The optical element according to claim 8, wherein the first surface of the first light-transmissive member focuses light incident thereon in the second light-transmissive member. ### Claim 10 (depends on 1) The optical element according to claim 1, wherein the first resin is a resin material containing a cycloolefin polymer as a primary component. ### Claim 11 (depends on 1) The optical element according to claim 1, wherein the silicone adhesive contains a dimethyl-based silicone adhesive as a primary component. ### Claim 12 (depends on 1) The optical element according to claim 1, further comprising: a third light-transmissive member having a third joint surface, made of a second resin, and disposed on a side opposite from the first light-transmissive member with the second light-transmissive member interposed therebetween; and a third joining member that joins the second light-transmissive member and the third light-transmissive member to each other, wherein The second light-transmissive member has a fourth joint surface disposed on a side opposite from the second joint surface and joined to the third joint surface by the third joining member, and the third joining member is made of the silicone adhesive, disposed in a smaller effective diameter region of the effective diameter region of the second light-transmissive member and the effective diameter region of the third light-transmissive member, and joined the third joint surface and the fourth joint surface to each other. ### Claim 13 (depends on 1) A projection optical apparatus that projects light incident thereon, the apparatus comprising: the optical element according to claim 1. ### Claim 14 (depends on 13) A projector comprising: a light modulator that modulates light outputted from a light source; and the projection optical apparatus according to claim 13, which projects the light modulated by the light modulator.