# US 2025/0093554 A1 · Burnish-resistant glass laminate with buried interference layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0093554 A1 - Document ID: US20250093554A1 - Status: Published application - Kind: A1 - Application number: 18/885,380 - Filed: 2024-09-13 - Published: 2025-03-20 - Earliest claimed: 2023-09-20 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Lijie Bao; Tyler R. Roschuk; Matthew S. Rogers - Web page: https://patentgrep.com/patent/US20250093554A1 ## CPC - G02B 1/14: Protective coatings, e.g. hard coatings - G02B 1/115: Multilayers - G02B 5/285: {comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361)} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An electronic device can include a housing, a display positioned within the housing; and a cover glass disposed over the display and attached to the housing. The cover glass can include a glass sheet; an intermediate hard-coat layer disposed on the glass sheet, having a hardness greater than a hardness of the glass sheet; an interference layer deposited on the intermediate hard-coat layer and having at least two layers with different optical constants and/or thicknesses; and an exterior hard-coat layer deposited on the interference layer. The optical constants and/or thicknesses of the interference layer can be selected based on an optical constant and/or thickness of the exterior hard-coat layer do minimize reflection of the cover glass. ## Claims ### Claim 1 An electronic device comprising: a housing; a display positioned within the housing; and a cover glass disposed over the display and attached to the housing, the cover glass comprising: a glass sheet; an interference layer disposed on the glass sheet, the interference layer having a first layer with a first optical constant and a second layer with a second optical constant, wherein the first optical constant is different than the second optical constant; and a hard-coat layer disposed on the interference layer and having a hardness that is greater than the glass sheet. ### Claim 2 (depends on 1) The electronic device of claim 1, wherein the interference layer includes three or more layers. ### Claim 3 (depends on 1) The electronic device of claim 1, wherein the first and the second optical constants are selected based at least in part on an optical constant of the hard-coat layer. ### Claim 4 (depends on 1) The electronic device of claim 1, wherein the hard-coat layer is predominantly SiON. ### Claim 5 (depends on 1) The electronic device of claim 1, wherein the interference layer comprises a third layer disposed on the second layer, and wherein the first layer is SiON, the second layer is SiO2 and the third layer is SiON. ### Claim 6 (depends on 1) The electronic device of claim 1, wherein the interference layer comprises a third layer disposed on the second layer, and wherein the first layer is SiN, the second layer is SiO2 and the third layer is SiN. ### Claim 7 (depends on 1) The electronic device of claim 1, further comprising a gradient layer disposed on the glass sheet and an intermediate hard-coat layer disposed on the gradient layer, wherein the interference layer is disposed on the intermediate hard-coat layer. ### Claim 8 (depends on 1) The electronic device of claim 1, wherein each of the first and the second layers have a thickness between 10 and 100 nanometers. ### Claim 9 (depends on 1) The electronic device of claim 1, wherein the interference layer interacts via destructive interference with the hard-coat layer to reduce a reflectance of the cover glass as compared to a reflectance of the cover glass without the interference layer. ### Claim 10 A cover glass comprising: a glass sheet; an interference layer disposed on the glass sheet, the interference layer having a first layer with a first optical constant and a second layer with a second optical constant, wherein the first optical constant is different than the second optical constant; and a hard-coat layer disposed on the interference layer and having a hardness that is greater than the glass sheet. ### Claim 11 (depends on 10) The cover glass of claim 10, wherein the interference layer includes three or more layers. ### Claim 12 (depends on 10) The cover glass of claim 10, wherein the first and second optical constants are selected based at least in part on an optical constant of the hard-coat layer. ### Claim 13 (depends on 10) The cover glass of claim 10, wherein the hard-coat layer is predominantly SiON. ### Claim 14 (depends on 10) The cover glass of claim 10, wherein the interference layer comprises a third layer disposed on the second layer, and wherein the first layer is SiON, the second layer is SiO2 and the third layer is SiON. ### Claim 15 (depends on 10) The cover glass of claim 10, wherein the interference layer comprises a third layer disposed on the second layer, and wherein the first layer is SiN, the second layer is SiO2 and the third layer is SiN. ### Claim 16 (depends on 10) The cover glass of claim 10, further comprising a gradient layer disposed on the glass sheet and an intermediate hard-coat layer disposed on the gradient layer, wherein the interference layer is disposed on the intermediate hard-coat layer. ### Claim 17 (depends on 10) The cover glass of claim 10, wherein each of the first and the second layers have a thickness between 10 and 100 nanometers. ### Claim 18 (depends on 10) The cover glass of claim 10, wherein the interference layer interacts with the hard-coat layer to reduce a reflectance of the cover glass as compared to a cover glass without the interference layer. ### Claim 19 A method of forming a transparent substrate, the method comprising: providing a glass sheet; depositing a gradient layer on the glass sheet; depositing an intermediate hard-coat layer on the gradient layer, wherein the gradient layer transitions from a composition of the glass sheet to a composition of the intermediate hard-coat layer; depositing an interference layer on the intermediate hard-coat layer, the interference layer having a first layer with a first optical constant and a second layer with a second optical constant, wherein the first optical constant is different than the second optical constant; and depositing a hard-coat layer on the interference layer, wherein a hardness of the hard-coat layer is greater than a hardness of the glass sheet. ### Claim 20 (depends on 19) The method of claim 19 wherein the interference layer comprises three or more layers.