# US 12,222,491 B2 · Electrostatic actuation for diffractive optical devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,491 B2 - Document ID: US12222491B2 - Status: Granted - Kind: B2 - Application number: 17/581,928 - Filed: 2022-01-23 - Published: 2022-12-01 - Granted: 2025-02-11 - Earliest claimed: 2021-05-27 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Sebastien Bolis; Arnaud Pouydebasque - Web page: https://patentgrep.com/patent/US12222491B2 ## CPC - G02B 26/0808: {by means of one or more diffracting elements} - G02B 5/1857: {using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams} - G03F 7/0005: {Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor} - G02B 5/1852: {using mechanical means, e.g. ruling with diamond tool, moulding} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract An optical device includes first and second planar substrates having respective first and second faces and including first and second diffractive structure disposed respectively on the first and second faces. First and second planar electrodes are disposed respectively on the first and second faces. A mount holds the second planar substrate parallel to the first planar substrate, with the second face adjacent to the first face and with the first and second planar electrodes in mutual proximity, while permitting the second planar substrate to move transversely relative to the first planar substrate. A control circuit is coupled to apply an electrical potential between the first and second planar electrodes with a voltage sufficient to shift the second diffractive structure transversely relative to the first diffractive structure. ## Claims ### Claim 1 An optical device, comprising: a first planar substrate having a first face and comprising a first diffractive structure disposed on the first face; a second planar substrate having a second face and comprising a second diffractive structure disposed on the second face; a first planar electrode disposed on the first face; a second planar electrode disposed on the second face; a mount holding the second planar substrate parallel to the first planar substrate, with the second face adjacent to the first face and with the first and second planar electrodes in mutual proximity, while permitting the second planar substrate to move transversely relative to the first planar substrate; and a control circuit, which is coupled to apply an electrical potential between the first and second planar electrodes with a voltage sufficient to shift the second diffractive structure transversely relative to the first diffractive structure. ### Claim 2 (depends on 1) The device according to claim 1, wherein the mount comprises a set of flexible beams connecting the second planar substrate to a frame to which the first planar substrate is fixed. ### Claim 3 (depends on 2) The device according to claim 2, wherein the flexible beams comprise silicon. ### Claim 4 (depends on 1) The device according to claim 1, and comprising third and fourth planar electrodes disposed in mutual proximity on the first and second faces, respectively, wherein the control circuit is configured to apply a first electrical potential between the first and second planar electrodes in order to shift the second diffractive structure relative to the first diffractive structure in a first transverse direction and to apply a second electrical potential between the third and fourth planar electrodes in order to shift the second diffractive structure relative to the first diffractive structure in a second transverse direction, different from the first transverse direction. ### Claim 5 (depends on 1) The device according to claim 1, wherein the first and second planar electrodes are interleaved respectively in the first and second diffractive structures. ### Claim 6 (depends on 5) The device according to claim 5, wherein the first and second planar electrodes are disposed in respective serpentine patterns within the first and second diffractive structures. ### Claim 7 (depends on 1) The device according to claim 1, wherein the second planar substrate has a third face opposite the second face, and wherein the device comprises; a planar cover, which has a fourth face and is mounted with the fourth face parallel to and in proximity to the third face; and third and fourth planar electrodes disposed in mutual proximity on the third and fourth faces, respectively, and wherein the control circuit is configured to apply simultaneously a first electrical potential between the first and second planar electrodes and a second electrical potential between the third and fourth planar electrodes in order to shift the second diffractive structure relative to the first diffractive structure. ### Claim 8 (depends on 1) The device according to claim 1, and comprising an actuator, which is controllable by the control circuit to apply a first transverse shift to the second diffractive structure relative to the first diffractive structure, wherein application of the electrical potential between the first and second planar electrodes applies a second transverse shift to the second diffractive structure in addition to the first transverse shift. ### Claim 9 (depends on 1) The device according to claim 1, and comprising a spacer, which is disposed between the first and second faces and is configured to maintain a predefined distance between the first and second faces while permitting the second planar substrate to move transversely relative to the first planar substrate. ### Claim 10 (depends on 9) The device according to claim 9, wherein the spacer comprises a liquid enclosed between the first and second faces. ### Claim 11 (depends on 9) The device according to claim 9, wherein the spacer comprises one or more spherical particles, which roll between the first and second faces as the second planar substrate moves transversely relative to the first planar substrate. ### Claim 12 (depends on 1) An optical system, comprising: the device according to claim 1; and a radiation source, which is configured to direct a beam of optical radiation toward the device, wherein shifting the second diffractive structure transversely relative to the first diffractive structure modifies an optical property of the beam. ### Claim 13 (depends on 12) The system according to claim 12, wherein the first and second planar substrates are transparent to the optical radiation, and the device is configured to modify the optical property as the beam is transmitted through the device. ### Claim 14 (depends on 12) The system according to claim 12, wherein the device is configured to modify the optical property as the beam is reflected from the device. ### Claim 15 A method for controlling a beam of optical radiation, the method comprising: directing the beam of optical radiation toward a device comprising: a first planar substrate having a first face and comprising a first diffractive structure disposed on the first face; a second planar substrate having a second face and comprising a second diffractive structure disposed on the second face; a first planar electrode disposed on the first face; a second planar electrode disposed on the second face; and a mount holding the second planar substrate parallel to the first planar substrate, with the second face adjacent to the first face and with the first and second planar electrodes in mutual proximity, while permitting the second planar substrate to move transversely relative to the first planar substrate; and applying an electrical potential between the first and second planar electrodes with a voltage sufficient to shift the second diffractive structure transversely relative to the first diffractive structure, thereby modifying an optical property of the beam. ### Claim 16 (depends on 15) The method according to claim 15, wherein the first and second planar substrates are transparent to the optical radiation, and wherein modifying the optical property comprises modifying the beam as the beam is transmitted through the device. ### Claim 17 A method for fabricating an optical device, comprising: forming a first diffractive structure on a first face of a first planar substrate; forming a second diffractive structure on a second face of a second planar substrate; depositing a first planar electrode on the first face; depositing a second planar electrode on the second face; mounting the second planar substrate parallel to the first planar substrate, with the second face adjacent to the first face and with the first and second planar electrodes in mutual proximity, while permitting the second planar substrate to move transversely relative to the first planar substrate; and coupling a control circuit to apply an electrical potential so as to shift the second diffractive structure transversely relative to the first diffractive structure. ### Claim 18 (depends on 17) The method according to claim 17, wherein forming the first diffractive structure and the second diffractive structure comprises applying at least one of an etching process and a nano-imprint process to the first face and the second face to create diffractive elements. ### Claim 19 (depends on 17) The method according to claim 17, wherein depositing the first planar electrode and the second planar electrode comprises interleaving at least one of the first and second planar electrodes with at least one of the first and second diffractive structures. ### Claim 20 (depends on 17) The method according to claim 17, wherein depositing the first planar electrode and the second planar electrode comprises depositing at least one of the first and second planar electrodes on at least one of the first face and the second face before forming the diffractive structure on the at least one of the first face and the second face.