# US 11,079,514 B2 · Optical element with high scratch resistance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,514 B2 - Document ID: US11079514B2 - Status: Granted - Kind: B2 - Application number: 16/212,197 - Filed: 2018-12-06 - Published: 2019-04-18 - Granted: 2021-08-03 - Earliest claimed: 2014-06-06 - Assignees: Schott AG - Applicants: Schott AG - Inventors: Dirk Apitz; Marten Walther; Christian Henn - Web page: https://patentgrep.com/patent/US11079514B2 ## CPC - G02B 1/11: Anti-reflection coatings - C23C 14/0036: {Reactive sputtering} - C23C 14/3414: {Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy} - C23C 14/46: by ion beam produced by an external ion source - G02B 1/115: Multilayers - G02B 1/14: Protective coatings, e.g. hard coatings - 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)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) ## Abstract An optical element is provided that includes a substrate that is transparent in the visible spectral region and a multilayer anti-reflection coating on the substrate. The coating has alternating layers of layers having a first refractive index and of layers having a second, higher refractive index. The layers having the higher refractive index contain nitride or oxynitride and the layers having the first refractive index contain oxide of silicon and of at least one other element. The molar fraction of silicon in the layers having the first refractive index is predominant when compared to the molar fraction(s) of the other element or elements. The uppermost layer of the coating is a layer having the first refractive index. A layer of chain-form organofluoro molecules is disposed on the coating, wherein the molecules are bonded at the ends to the surface of the optical element. ## Claims ### Claim 1 An optical element with high scratch resistance, comprising: a substrate that is transparent in the visible spectral region; a multilayer anti-reflection coating on the substrate, the multilayer anti-reflection coating having alternating layers of a first layer type having a first refractive index and a second layer type having a second, higher refractive index, the second layer type comprising nitride or oxynitride, the first layer type comprising oxide of silicon and at least one other element, the first layer type having a ratio of silicon to the at least one other element of at least 5:1, wherein the multilayer anti-reflection coating has an uppermost layer that comprises the first layer type; and a layer of chain-form organofluoro molecules on the multilayer anti-reflection coating, the layer having molecules that are bonded at their ends to the uppermost layer of the multilayer anti-reflection coating wherein the optical element is configured for a use selected from the group consisting of a closing element, a window of optics of a camera, a sensor, and a cover glass for watches, objectives or optical measuring instruments. ### Claim 2 (depends on 1) The optical element according to claim 1, wherein the layer of chain-form organofluoro molecules is a monomolecular layer. ### Claim 3 (depends on 1) The optical element according to claim 1, wherein the layer of chain-form organofluoro molecules comprise molecules with perfluorinated carbon chains. ### Claim 4 (depends on 1) The optical element according to claim 1, wherein the at least one other element of the first layer type is an element selected from the group consisting of aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, barium, strontium, niobium, and boron. ### Claim 5 (depends on 1) The optical element according to claim 1, wherein the substrate comprises a sapphire substrate. ### Claim 6 (depends on 1) The optical element according to claim 1, wherein the substrate comprises a chemically prestressed glass substrate. ### Claim 7 (depends on 1) The optical element according to claim 1, wherein the multilayer anti-reflection coating comprises a stack of four successive layers, the multilayer anti-reflection coating having a lowermost layer that comprises the second layer type, the uppermost layer having a second-greatest layer thickness among the stack, and wherein the lowermost layer and an adjacent layer of the first layer type together have a layer thickness that is thinner than a layer thickness of the uppermost layer. ### Claim 8 (depends on 7) The optical element according to claim 7, wherein the at least one other element of the layers of the first layer type comprises aluminum. ### Claim 9 (depends on 1) The optical element according to claim 1, wherein the multilayer anti-reflection coating has an upper layer of the second layer type that has a greatest layer thickness of the multilayer anti-reflection coating and has a layer thickness in the range of 100 nm to 700 nm. ### Claim 10 (depends on 9) The optical element according to claim 9, wherein the layer thickness is in the range of 400 nm to 500 nm. ### Claim 11 (depends on 1) The optical element according to claim 1, wherein the ratio of silicon to the at least one other element is at least 8:1. ### Claim 12 (depends on 1) The optical element according to claim 1, wherein the optical element has a Knoop hardness of at least 600 kilograms per square millimeter. ### Claim 13 (depends on 1) The optical element according to claim 1, wherein the substrate has a modulus of elasticity of at least 50 GPa. ### Claim 14 (depends on 1) The optical element according to claim 1, wherein the multilayer anti-reflection coating comprises a stack of four successive layers comprising two layers of the first layer type and two layers of the second layer type, an upper of the two layers of the second layer type having a layer thickness that amounts to at least 40% of a thickness of the multilayer anti-reflection coating. ### Claim 15 (depends on 14) The optical element according to claim 14, wherein the upper of the two layers of the second layer type has a layer thickness that amounts to at least 70% of the thickness. ### Claim 16 A method for producing an optical element, comprising: preparing a substrate that is transparent in the visible spectral region; vacuum depositing a multilayer anti-reflection coating onto the substrate by alternating layers of a first layer type having a first refractive index and a second layer type having a second, higher refractive index, wherein the second layer type comprises nitride or oxynitride and the first layer type comprises oxide of silicon and at least one other element, wherein the first layer type has a ratio of silicon to the at least one other element of at least 5:1, and wherein the multilayer anti-reflection coating has an uppermost layer that comprises the first layer type; and applying a layer of chain-form organofluoro molecules on the multilayer anti-reflection coating so that molecules of the layer are bonded at their ends to the uppermost layer, wherein the layer and the multilayer anti-reflection coating reduce, when compared to the multilayer anti-reflection coating without the layer, an increase in haze-value after a modified Bayer test on a plurality of samples according to ASTM F735-11 with 8000 cycles; and wherein the optical element is configured for a use selected from the group consisting of a closing element, a window of optics of a camera, a sensor, and a cover glass for watches, objectives or optical measuring instruments. ### Claim 17 (depends on 16) The method according to claim 16, wherein the step of vacuum depositing comprises reactive magnetron sputtering. ### Claim 18 (depends on 16) The method according to claim 16, wherein the step of applying the layer comprises liquid coating. ### Claim 19 (depends on 16) The method according to claim 16, wherein the step of applying the layer comprises vaporizing in a vacuum deposition method. ### Claim 20 An optical element with high scratch resistance, comprising: a substrate that is transparent in the visible spectral region; a multilayer anti-reflection coating comprising a first, uppermost layer of a first layer type, a second layer of a second layer type, a third layer of the first layer type, and a fourth, bottommost layer of the second layer type on the substrate, wherein the first layer type has a first refractive index and comprises oxide of silicon and at least one other element in a ratio of silicon to the at least one other element of at least 5:1, wherein the second layer type has a second, higher refractive index and comprises nitride or oxynitride, wherein the second layer has a layer thickness that is a greatest layer thickness within the multilayer anti-reflection coating and amounts to at least 40% of a thickness of the multilayer anti-reflection coating; and a layer of chain-form organofluoro molecules on the multilayer anti-reflection coating, the layer having molecules that are bonded at their ends to the uppermost layer, wherein the layer of chain-form organofluoro molecules and the multilayer anti-reflection coating reduce, when compared to the multilayer anti-reflection coating without the layer, an increase in haze-value after a modified Bayer test on a plurality of samples according to ASTM F735-11 with 8000 cycles; and wherein the optical element is configured for a use selected from the group consisting of a closing element, a window of optics of a camera, a sensor, and a cover glass for watches, objectives or optical measuring instruments. ### Claim 21 (depends on 20) The optical element according to claim 20, wherein the at least one other element of the first layer type comprises aluminum. ### Claim 22 (depends on 20) The optical element according to claim 20, wherein the layer thickness of the second layer amounts to at least 70% of the thickness of the multilayer anti-reflection coating. ### Claim 23 An optical element with high scratch resistance, comprising: a substrate that is transparent in the visible spectral region; a multilayer anti-reflection coating comprising a first, uppermost layer of a first layer type, a second layer of a second layer type, a third layer of the first layer type, and a fourth, bottommost layer of the second layer type on the substrate, wherein the first layer type has a first refractive index and comprises oxide of silicon and at least one other element in a ratio of silicon to the at least one other element of at least 5:1, wherein the second layer type has a second, higher refractive index and comprises nitride or oxynitride, wherein the second layer has a layer thickness that is a greatest layer thickness within the multilayer anti-reflection coating and amounts to at least 40% of a thickness of the multilayer anti-reflection coating; and a layer of chain-form organofluoro molecules on the multilayer anti-reflection coating, the layer having molecules that are bonded at their ends to the uppermost layer, wherein the layer of chain-form organofluoro molecules and the multilayer anti-reflection coating reduce by 27% when compared to the multilayer anti-reflection coating without the layer of chain-form organofluoro molecules, an increase in haze-value after a modified Bayer test on a plurality of samples according to ASTM F735-11 with 8000 cycles.