# US 2024/0201045 A1 · Display device inspecting apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0201045 A1 - Document ID: US20240201045A1 - Status: Published application - Kind: A1 - Application number: 18/363,931 - Filed: 2023-08-02 - Published: 2024-06-20 - Earliest claimed: 2022-12-19 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: Junsu Park; Namhyuk Kim; Sangjun Seok - Web page: https://patentgrep.com/patent/US20240201045A1 ## CPC - G01M 11/081: {by using a contact-less detection method, i.e. with a camera} - G01B 11/2408: {for measuring roundness} - G01B 11/2513: {with several lines being projected in more than one direction, e.g. grids, patterns} - G01B 11/2527: {with phase change by in-plane movement of the patern} - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A method of inspecting a flexural strength of a glass including a folding area of a display apparatus includes a sample glass surface measurement operation of measuring a three-dimensional shape of a surface of each of a plurality of sample glasses, a sample glass curvature variable calculation operation of calculating a plurality of curvature variables of each of the plurality of sample glasses based on an information measured in the sample glass surface measurement operation, a sample glass flexural strength measurement operation of measuring a flexural strength of each of the plurality of sample glasses, a data analysis operation including a relational expression generation operation of generating a relational expression between the plurality of curvature variables and the flexural strength, and a flexural strength prediction operation of predicting a flexural strength of a target glass based on the relational expression. ## Claims ### Claim 1 A method of inspecting a flexural strength of a glass including a folding area of a display apparatus, the method comprising: a sample glass surface measurement operation of measuring a three-dimensional shape of a surface of each of a plurality of sample glasses; a sample glass curvature variable calculation operation of calculating a plurality of curvature variables of the each of the plurality of sample glasses based on an information measured in the sample glass surface measurement operation; a sample glass flexural strength measurement operation of measuring a flexural strength of the each of the plurality of sample glasses; a data analysis operation comprising a relational expression generation operation of generating a relational expression between the plurality of curvature variables and the flexural strength; and a flexural strength prediction operation of predicting a flexural strength of a target glass based on the relational expression, wherein the flexural strength prediction operation comprises: a target glass surface measurement operation of measuring a three-dimensional shape of a surface of the target glass; a target glass curvature variable calculation operation of calculating a plurality of curvature variables of the target glass based on an information measured in the target glass surface measurement operation; and a target glass flexural strength calculation operation of calculating the flexural strength of the target glass by inputting the plurality of curvature variables calculated in the target glass curvature variable calculation operation in the relational expression. ### Claim 2 (depends on 1) The method of claim 1, wherein the data analysis operation further comprises a curvature variable selection operation of selecting a plurality of correlative curvature variables correlated to the flexural strength among the plurality of curvature variables, and the relational expression generation operation is an operation of generating a relational expression between the plurality of correlative curvature variables and the flexural strength. ### Claim 3 (depends on 2) The method of claim 2, wherein the target glass curvature variable calculation operation is an operation of calculating the plurality of correlative curvature variables of the target glass. ### Claim 4 (depends on 3) The method of claim 3, wherein the target glass flexural strength calculation operation is an operation of calculating the flexural strength of the target glass by inputting the plurality of correlative curvature variables in the relational expression. ### Claim 5 (depends on 2) The method of claim 2, wherein the plurality of curvature variables comprise at least two of a curvature average of an entire surface, a curvature standard deviation of the entire surface, a curvature absolute value average of the entire surface, a curvature absolute value standard deviation of the entire surface, a curvature average of the folding area, a curvature standard deviation of the folding area, a curvature absolute value average of the folding area, and a curvature absolute value standard deviation of the folding area. ### Claim 6 (depends on 5) The method of claim 5, wherein the plurality of correlative curvature variables comprise the curvature average of the folding area and the curvature standard deviation of the folding area. ### Claim 7 (depends on 1) The method of claim 1, further comprising: a data storing operation of storing data about the plurality of curvature variables calculated in the sample glass curvature variable calculation operation and the flexural strength measured in the sample glass flexural strength measurement operation. ### Claim 8 (depends on 1) The method of claim 1, wherein the data analysis operation follows a multiple regression analysis method. ### Claim 9 (depends on 1) The method of claim 1, wherein the sample glass surface measurement operation is an operation of measuring the three-dimensional shape of the surface of the each of the plurality of sample glasses by using a phase measuring deflectometry. ### Claim 10 (depends on 1) The method of claim 1, wherein the target glass surface measurement operation is an operation of measuring the three-dimensional shape of the surface of the target glass by using a phase measuring deflectometry. ### Claim 11 An apparatus for inspecting a flexural strength of a glass including a folding area of a display apparatus, the apparatus comprising: a surface measurement part that measures a three-dimensional shape of a surface of each of a plurality of sample glasses and a target glass; a flexural strength measurement part that measures a flexural strength of the each of the plurality of sample glasses; and an operation part that calculates a flexural strength of the target glass, wherein the operation part comprises: a sample glass curvature variable calculation part that calculates a plurality of curvature variables of the each of the plurality of sample glasses based on the three-dimensional shape of the surface of the each of the plurality of sample glasses; a data analysis part comprising a relational expression generation part that generates a relational expression between the plurality of curvature variables and the flexural strength; and a flexural strength prediction part that predicts the flexural strength of the target glass based on the relational expression, and the flexural strength prediction part comprises: a target glass curvature variable calculation part that calculates the plurality of curvature variables of the target glass based on the three-dimensional shape of the surface of the target glass; and a target glass flexural strength calculation part that calculates the flexural strength of the target glass by inputting the plurality of curvature variables calculated in the target glass curvature variable calculation part in the relational expression. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the data analysis part further comprises a curvature variable selection part that selects a plurality of correlative curvature variables correlated to the flexural strength among the plurality of curvature variables, and the relational expression generation part generates a relational expression between the plurality of correlative curvature variables and the flexural strength. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the target glass curvature variable calculation part calculates the plurality of correlative curvature variables of the target glass. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the target glass flexural strength calculation part calculates the flexural strength of the target glass by inputting the plurality of correlative curvature variables in the relational expression. ### Claim 15 (depends on 12) The apparatus of claim 12, wherein the surface of the each of the plurality of sample glasses includes a folding area that is foldable, and the plurality of curvature variables comprise at least two of a curvature average of an entire surface, a curvature standard deviation of the entire surface, a curvature absolute value average of the entire surface, a curvature absolute value standard deviation of the entire surface, a curvature average of the folding area, a curvature standard deviation of the folding area, a curvature absolute value average of the folding area, and a curvature absolute value standard deviation of the folding area. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the plurality of correlative curvature variables comprise the curvature average of the folding area and the curvature standard deviation of the folding area. ### Claim 17 (depends on 11) The apparatus of claim 11, wherein the operation part further comprises a database storing data about the plurality of curvature variables calculated by the sample glass curvature variable calculation part and the flexural strength of the each of the plurality of sample glasses measured by the flexural strength measurement part. ### Claim 18 (depends on 11) The apparatus of claim 11, wherein the data analysis part follows a multiple regression analysis method. ### Claim 19 (depends on 11) The apparatus of claim 11, wherein the surface measurement part measures the three-dimensional shape of the surface of the each of the plurality of sample glasses and the target glass by using a phase measuring deflectometry. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the surface measurement part comprises: a screen part that outputs pattern light to be irradiated onto the surface of the each of the plurality of sample glasses and the target glass; and a camera part that measures the pattern light reflected from the surface of the each of the plurality of sample glasses and the target glass.