# US 10,502,880 B2 · Method of fabricating anisotropic optical interference filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,880 B2 - Document ID: US10502880B2 - Status: Granted - Kind: B2 - Application number: 15/797,894 - Filed: 2017-10-30 - Published: 2018-02-22 - Granted: 2019-12-10 - Earliest claimed: 2015-02-17 - Assignees: Materion Corporation - Applicants: Materion Corporation - Inventors: Robert Sprague - Web page: https://patentgrep.com/patent/US10502880B2 ## CPC - C23C 14/044: {using masks to redistribute rather than totally prevent coating, e.g. producing thickness gradient} - G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)} - 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) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract In a method of manufacturing a one-dimensionally varying optical filter, a substrate is coated to form a stack of layers of two or more different types. The coating may, for example, employ sputtering, electron-beam evaporation, or thermal evaporation. During the coating, the time-averaged deposition rate is varied along an optical gradient direction by generating reciprocation between a shadow mask and the substrate in a reciprocation direction that is transverse to the optical gradient direction. In some approaches, the shadow mask is periodic with a mask period defined along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. The substrate and the shadow mask may also be rotated together as a unit during the coating. Also disclosed are one-dimensionally varying optical filters, such as linear variable filters, made by such methods. ## Claims ### Claim 1 A method of manufacturing a one-dimensionally varying optical filter, the method comprising: providing a shadow mask wafer having a plurality of shadow masks disposed thereon, at least one of the plurality of shadow masks having an opening fraction along a direction of reciprocation that varies along a direction transverse to the direction of reciprocation; coating a substrate through the at least one shadow mask to form a stack of layers of two or more different types; and during the coating, generating reciprocation between the shadow mask wafer and the substrate in the direction of reciprocation. ### Claim 2 (depends on 1) The method of claim 1 further comprising: during the coating, rotating the substrate and the shadow mask wafer together as a unit. ### Claim 3 (depends on 1) The method of claim 1 wherein the providing comprises: providing the shadow mask wafer having the plurality of shadow masks disposed thereon, wherein the at least one of the plurality of shadow masks having a one-dimensional array of wedge-shaped openings along the direction of reciprocation with each wedge extending from a narrow end to a wide end along the direction transverse to the direction of reciprocation. ### Claim 4 (depends on 1) The method of claim 1 wherein the providing comprises: providing the shadow mask wafer having the plurality of shadow masks disposed thereon, wherein the at least one of the plurality of shadow masks having a density of openings along the direction of reciprocation that varies along the direction transverse to the direction of reciprocation. ### Claim 5 (depends on 1) The method of claim 1 wherein the variation of the opening fraction along the direction transverse to the direction of reciprocation is effective to deposit the one-dimensionally varying optical filter as a linear variable filter. ### Claim 6 (depends on 1) The method of claim 1 wherein the opening fraction of the at least one shadow mask along the direction of reciprocation varies non-linearly along the direction transverse to the direction of reciprocation. ### Claim 7 (depends on 1) The method of claim 1 wherein the coating comprises one of sputtering, electron-beam evaporation, and thermal evaporation. ### Claim 8 (depends on 1) The method of claim 1 wherein: the providing comprises providing the at least one of the plurality of shadow masks on the shadow mask wafer having a repeating pattern of one or more openings along the direction of reciprocation; and the generated reciprocation has a stroke equal to or greater than the period of the repeating pattern of one or more openings along the direction of reciprocation. ### Claim 9 (depends on 1) The method of claim 1 wherein the operation of generating reciprocation between the shadow mask wafer and the substrate consists of one of: reciprocating the shadow mask wafer in the direction of reciprocation while not reciprocating the substrate; and reciprocating the substrate in the direction of reciprocation while not reciprocating the shadow mask wafer. ### Claim 10 (depends on 1) A one-dimensionally varying optical filter manufactured by a method as set forth in claim 1. ### Claim 11 A method of manufacturing a one-dimensionally varying optical filter, the method comprising: coating a substrate through at least one of a plurality of shadow masks on a shadow mask wafer to form a stack of layers of two or more different types; and during the coating, generating reciprocation between the shadow mask wafer and the substrate wherein the at least one of the plurality of shadow masks has openings configured to, in combination with the generated reciprocation, define a coating duty cycle that varies along a direction transverse to the direction of reciprocation. ### Claim 12 (depends on 11) The method of claim 11 further comprising: during the coating, rotating the substrate and the shadow mask wafer together as a unit. ### Claim 13 (depends on 11) The method of claim 11 wherein the at least one of the plurality of shadow masks has a one-dimensional array of wedge-shaped openings along the direction of reciprocation with each wedge extending from a narrow end to a wide end along the direction transverse to the direction of reciprocation. ### Claim 14 (depends on 11) The method of claim 11 wherein the at least one of the plurality of shadow masks has a density of openings along the direction of reciprocation that varies along the direction transverse to the direction of reciprocation. ### Claim 15 (depends on 11) The method of claim 11 wherein the openings in combination with the generated reciprocation are configured to define a coating duty cycle variation along the direction transverse to the direction of reciprocation that is effective to deposit the one-dimensionally varying optical filter as a linear variable filter. ### Claim 16 (depends on 11) The method of claim 11 wherein the coating comprises one of sputtering, electron-beam evaporation, and thermal evaporation. ### Claim 17 (depends on 11) The method of claim 11 wherein: the at least one of the plurality of shadow masks has a repeating pattern of one or more openings along the direction of reciprocation defining a mask period along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. ### Claim 18 (depends on 11) The method of claim 11 wherein the operation of generating reciprocation between the shadow mask wafer and the substrate consists of one of: reciprocating the shadow mask wafer in the direction of reciprocation while not reciprocating the substrate; and reciprocating the substrate in the direction of reciprocation while not reciprocating the shadow mask wafer. ### Claim 19 (depends on 11) A linear variable filter manufactured by a method as set forth in claim 11. ### Claim 20 A method of manufacturing a one-dimensionally varying optical filter, the method comprising: coating a substrate to form a stack of layers of two or more different types; and during the coating, varying the time-averaged deposition rate along an optical gradient direction by generating reciprocation between a shadow mask wafer having a plurality of shadow masks disposed thereon and the substrate in a reciprocation direction that is transverse to the optical gradient direction. ### Claim 21 (depends on 20) The method of claim 20 further comprising: during the coating, rotating the substrate and the shadow mask wafer together as a unit. ### Claim 22 (depends on 21) A method of claim 21 further comprising rotating the rotating unit of the substrate and the shadow mask wafer about a second axis as a planet in a planetary configuration. ### Claim 23 (depends on 20) The method of claim 20 wherein the coating comprises one of sputtering, electron-beam evaporation, and thermal evaporation. ### Claim 24 (depends on 20) The method of claim 20 wherein: at least one of the plurality of shadow masks is periodic with a mask period defined along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. ### Claim 25 (depends on 20) The method of claim 20 wherein the operation of generating reciprocation between the shadow mask wafer and the substrate consists of one of: reciprocating the shadow mask wafer in the direction of reciprocation while not reciprocating the substrate; and reciprocating the substrate in the direction of reciprocation while not reciprocating the shadow mask wafer. ### Claim 26 A method of manufacturing a one-dimensionally varying optical filter, the method comprising: providing a shadow mask wafer having a plurality of shadow masks disposed therein, wherein at least one of the plurality of shadow masks having openings; coating a substrate through the at least one shadow mask to form a stack of layers of two or more different types; and during the coating, generating reciprocation between the shadow mask wafer and the substrate in the direction of reciprocation; wherein the duty cycle of the reciprocating is varied during the coating in order to produce a multiplicity of filters having similar profiles but differing wavelength characteristics via a single deposition. ### Claim 27 (depends on 26) The method of claim 26 wherein the openings of the at least one of the plurality of shadow masks do not have an opening fraction along a direction of reciprocation that varies along a direction transverse to the direction of reciprocation.