# US 9,039,906 B2 · Method for producing an antireflection coating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,906 B2 - Document ID: US9039906B2 - Status: Granted - Kind: B2 - Application number: 14/309,582 - Filed: 2014-06-19 - Published: 2014-12-25 - Granted: 2015-05-26 - Earliest claimed: 2013-06-19 - Assignees: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. - Applicants: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. - Inventors: Ulrike Schulz; Peter Munzert; Friedrich Rickelt; Norbert Kaiser - Web page: https://patentgrep.com/patent/US9039906B2 ## CPC - G02B 1/111: using layers comprising organic materials - B29C 59/14: by plasma treatment {(plasma tubes per se H01J)} - B29D 11/00865: {Applying coatings; tinting; colouring (printing, marking or copying processes B41M; identification in general G09F3/00; producing decorative effects in general B44C; positioning or marking of lenses B24B13/0055)} - C08J 7/123: {Treatment by wave energy or particle radiation (C08J7/18 takes precedence)} - G02B 1/118: having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures - G02B 1/12: by surface treatment, e.g. by irradiation - B29C 2059/147: {Low pressure plasma; Glow discharge plasma} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) ## Abstract A method for producing an antireflection coating on a substrate is specified. A first nanostructure in a first material is formed using by means of a first plasma etching process. The first material is the material of the substrate or the material of a layer made of a first organic material applied onto the substrate. A layer made of a second material is applied onto the first nanostructure, the second material is an organic material. A second nanostructure is formed in the layer made of the second material using a second plasma etching process. The second material has a higher etching rate than the first material when carrying out the second plasma etching process. ## Claims ### Claim 1 A method for producing an antireflection coating on a substrate, the method comprising: forming a first nanostructure in a first material using a first plasma etching process, wherein the first material is a material of the substrate or a material of a layer made of a first organic material applied onto the substrate; applying a layer made of a second material onto the first nanostructure, wherein the second material is an organic material; and forming a second nanostructure in the layer made of the second material using a second plasma etching process, wherein the second material has a higher etching rate than the first material when carrying out the second plasma etching process. ### Claim 2 (depends on 1) The method according to claim 1, wherein the first nanostructure has a depth of between 100 nm and 200 nm. ### Claim 3 (depends on 1) The method according to claim 1, wherein a refractive index gradient is generated in the first material by means of the first nanostructure such that the refractive index decreases with increasing distance from the substrate. ### Claim 4 (depends on 1) The method according to claim 1, wherein the first nanostructure has a mean effective refractive index n1 of between 1.25 and 1.4. ### Claim 5 (depends on 1) The method according to claim 1, wherein the layer made of the second material is applied with a layer thickness of between 200 nm and 400 nm onto the first nanostructure. ### Claim 6 (depends on 1) The method according to claim 1, wherein the second nanostructure has a depth of between 100 nm and 200 nm. ### Claim 7 (depends on 1) The method according to claim 1, wherein a refractive index gradient is generated in the layer made of the second material by means of the second nanostructure such that the refractive index decreases with increasing distance from the substrate. ### Claim 8 (depends on 1) The method according to claim 1, wherein the second nanostructure has a mean effective refractive index n2 of between 1.08 and 1.25. ### Claim 9 (depends on 1) The method according to claim 1, wherein the first nanostructure and/or the second nanostructure each have structure elements in the form of elevations, recesses and/or pores, the width of which on average is less than 150 nm. ### Claim 10 (depends on 1) The method according to claim 1, further comprising applying an etch stop layer onto the first nanostructure before applying the layer made of the second material, wherein the etch stop layer has a thickness of no more than 30 nm. ### Claim 11 (depends on 1) The method according to claim 1, further comprising applying a protection layer onto the second nanostructure after generating the second nanostructure, wherein the protection layer has a thickness of no more than 30 nm. ### Claim 12 (depends on 1) The method according to claim 1, wherein the first material is the material of the substrate and the substrate comprises PMMA, polycarbonate, a cycloolefin, polyamide or PTFE. ### Claim 13 (depends on 1) The method according to claim 1, wherein the first material is the material of a layer made of a first organic material applied onto the substrate. ### Claim 14 (depends on 1) The method according to claim 1, wherein the substrate is a curved substrate. ### Claim 15 (depends on 1) The method according to claim 1, wherein the substrate has a refractive index ns<1.7.