# US 2026/0287799 A1 · Transparent optical structure and manufacturing method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0287799 A1 - Document ID: US20260287799A1 - Status: Published application - Kind: A1 - Application number: 19/558,129 - Filed: 2026-03-05 - Published: 2026-09-24 - Earliest claimed: 2025-03-19 - Assignees: STMicroelectronics International N.V. - Applicants: STMicroelectronics International N.V. - Inventors: Maxime ARGOUD; Francois GUYADER; Pierre TISSIER - Web page: https://patentgrep.com/patent/US20260287799A1 ## CPC - G02B 5/0236: {the diffusion taking place within the volume of the element} - G02B 1/14: Protective coatings, e.g. hard coatings - G02B 5/0268: {characterized by the fabrication or manufacturing method} - G02B 5/0278: {used in transmission} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract The present description concerns a method for manufacturing a transparent optical structure 10, including a step of making a protective layer covering a conductive layer 21, by CVD deposition under vacuum, with thermally exposing to a first temperature T1 greater than, or equal to within 10%, to a second temperature T2 at least equal to 300°C for a first duration Δt1 greater than, or equal to within 10%, a second duration Δt2 at least equal to 60min; and then a subsequent step of thermally exposing to the temperature T2 for the duration Δt2. ## Claims ### Claim 1 A method for manufacturing a transparent optical structure, the method comprising: forming a transparent layer; forming a conductive layer, which is made of a transparent and electrically conductive material, on a face of the transparent layer; forming a protective layer, which is made of a transparent and electrically insulating material, on the conductive layer by chemical vapor deposition; forming a conductive track, covered with a protective track, by lithography and etching the protective layer and the conductive layer; forming an encapsulation layer, which is made of a transparent and electrically insulating material, on the transparent layer, the protective track, and the conductive track. ### Claim 2 (depends on 1) The method according to claim 1, wherein forming the protective layer is performed by chemical vapor deposition under vacuum. ### Claim 3 (depends on 1) The method according to claim 1, wherein forming the protective layer includes thermally exposing the conductive layer to a first temperature greater than, or equal to within 10%, to a second temperature at least equal to 300°C for a first duration greater than, or equal to within 10%, to a second duration at least equal to 60 minutes. ### Claim 4 (depends on 3) The method according to claim 3, further comprising: subsequent to forming the encapsulation layer, thermally exposing to the second temperature for the second duration. ### Claim 5 (depends on 3) The method according to claim 3, wherein forming the protective layer includes: thermally exposing to the first temperature T1 for the first duration, performed in an enclosure of a chemical vapor deposition reactor, formation precursors of the protective layer not being present in the enclosure; and forming the protective layer in the enclosure by injecting the precursors. ### Claim 6 (depends on 1) The method according to claim 1, wherein, after the transparent optical structure leaves a layer deposition reactor used during forming the conductive layer, until introducing the transparent optical structure into a Chemical Vapor Deposition (CVD) reactor used during forming the protective layer, the protective layer remains at a temperature less than or equal to 100°C in an environment at atmospheric pressure. ### Claim 7 (depends on 1) The method according to claim 1, wherein the conductive layer is made of an oxide. ### Claim 8 (depends on 1) The method according to claim 1, wherein the protective layer is made of a silicon oxide or nitride. ### Claim 9 (depends on 3) The method according to claim 3, wherein the first temperature T1 and the second temperature T2 are between 300°C and 400°C. ### Claim 10 (depends on 1) The method according to claim 1, wherein, when forming the protective layer, the pressure is between 1 and 10 Torr. ### Claim 11 (depends on 4) The method according to claim 4, further comprising: assembling a transparent substrate on the encapsulation layer, by direct bonding, during which the thermally exposing to the second temperature T2 is performed for the second duration. ### Claim 12 (depends on 4) The method according to claim 4, further comprising: forming an additional layer, during which the thermally exposing to the second temperature is performed for the second duration. ### Claim 13 A transparent optical structure, comprising: a transparent layer; a conductive track, extending on a face of the transparent layer, made of a transparent and electrically conductive material; a protective track, covering a face of the conductive track opposite to the transparent layer, made of a transparent and electrically insulating material; and an encapsulation layer, made of a transparent and electrically insulating material, covering the transparent layer, the protective track, and the conductive track. ### Claim 14 (depends on 13) The transparent optical structure according to claim 13, wherein the transparent layer, the protective track, and the encapsulation layer are made of silicon-based materials, and the conductive track is made of a transparent conductive oxide. ### Claim 15 (depends on 13) The transparent optical structure according to claim 13, further comprising: a transparent substrate assembled by direct bonding to the encapsulation layer, or an additional layer covering the encapsulation layer. ### Claim 16 (depends on 13) The transparent optical structure according to claim 13, wherein the conductive track has a thickness between 5nm and 200nm, and the protective track has a thickness between 5nm and 200nm. ### Claim 17 An optical diffuser, comprising: a transparent layer; a conductive track, extending on a face of the transparent layer, made of a transparent and electrically conductive material; a protective track, covering a face of the conductive track opposite to the transparent layer, made of a transparent and electrically insulating material; and an encapsulation layer, made of a transparent and electrically insulating material, covering the transparent layer, the protective track, and the conductive track, wherein the transparent layer is a diffusing layer including diffusing structures arranged in a main plane of the transparent layer and located in an encapsulating material having a refractive index different from that of the diffusing structures. ### Claim 18 (depends on 17) The optical diffuser according to claim 17, wherein the transparent layer, the protective track, and the encapsulation layer are made of silicon-based materials, and the conductive track is made of a transparent conductive oxide. ### Claim 19 (depends on 17) The optical diffuser according to claim 17, further comprising: a transparent substrate assembled by direct bonding to the encapsulation layer, or an additional layer covering the encapsulation layer. ### Claim 20 (depends on 17) The optical diffuser according to claim 17, wherein the conductive track has a thickness between 5nm and 200nm, and the protective track has a thickness between 5nm and 200nm.