# US 2023/0410286 A1 · Apparatus for inspecting display panel and method for inspecting surface of display panel

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- Number: US 2023/0410286 A1
- Document ID: US20230410286A1
- Status: Published application
- Kind: A1
- Application number: 18/119,369
- Filed: 2023-03-09
- Published: 2023-12-21
- Earliest claimed: 2022-06-21
- Assignees: Samsung Display Co., Ltd.
- Applicants: Samsung Display Co., LTD.
- Inventors: Ja Eun LEE; Jin SEO
- Web page: https://patentgrep.com/patent/US20230410286A1

## CPC

- G06T 7/001: {using an image reference approach}
- G01B 11/24: for measuring contours or curvatures
- G01B 11/2408: {for measuring roundness}
- G01N 21/95: characterised by the material or shape of the object to be examined (G01N21/89 - G01N21/91, G01N21/94 take precedence)
- G06T 7/70: Determining position or orientation of objects or cameras (camera calibration G06T7/80)
- H04N 23/56: provided with illuminating means
- G01N 2021/9513: {Liquid crystal panels}
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An apparatus for inspecting a display panel includes a light source irradiating light toward a surface of the display panel; a light detector detecting light reflected from a region of interest on the surface of the display panel to generate a captured image; a lens system including at least one lens receiving the reflected light and providing reflected light to the light detector; and an analyzer quantifying a degree of curvature of the region of interest based on a result of comparing modeling data including distribution of reference light intensity for the region of interest with detection data corresponding to the captured image, and determining whether the display panel is defective based on a quantified result.

## Claims

### Claim 1

An apparatus for inspecting a display panel comprising:
a light source irradiating light toward a surface of the display panel;
a light detector detecting light reflected from a region of interest on the surface of the display panel to generate a captured image;
a lens system including at least one lens receiving reflected light and providing the reflected light to the light detector; and
an analyzer quantifying a degree of curvature of the region of interest based on a result of comparing modeling data including distribution of reference light intensity for the region of interest with detection data corresponding to the captured image, and determining whether the display panel is defective based on a quantified result.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising:
an optical system adjusting the light emitted from the light source into parallel light, providing the parallel light to the region of interest, and adjusting a diameter of the parallel light according to a size of the region of interest.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the analyzer includes:
a storage storing the modeling data according to the region of interest;
a first calculator calculating differences in magnitudes of data values for each coordinate between the modeling data and the detection data;
a second calculator calculating a total sum of the differences in magnitudes as a representative value corresponding to the degree of curvature; and
a determiner comparing the representative value with a threshold value to determine whether the display panel is defective.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein
the determiner determines that the display panel is defective in case that the representative value exceeds the threshold value, and
the determiner determines that the display panel is normal in case that the representative value is equal to or less than the threshold value.

### Claim 5 (depends on 3)

The apparatus of claim 3, wherein the analyzer further includes:
a reference position extractor extracting, as reference coordinates, coordinates of a position corresponding to a maximum value of light intensity included in the detection data; and
a modeling data corrector generating corrected modeling data by shifting the modeling data so that coordinates of a position corresponding to a maximum value of the reference light intensity included in the modeling data coincide with the reference coordinates.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the first calculator calculates differences in magnitudes of data values for each coordinate between the corrected modeling data and the detection data.

### Claim 7 (depends on 5)

The apparatus of claim 5, wherein the first calculator normalizes data values of the corrected modeling data based on a maximum value included in the corrected modeling data.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the first calculator normalizes data values of the detection data based on a maximum value included in the detection data.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the first calculator calculates differences in magnitudes of normalized values for each coordinate of the detection data and the corrected modeling data.

### Claim 10 (depends on 3)

The apparatus of claim 3, wherein the detection data of the display panel determined to be normal is stored in the storage as the modeling data.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein the light detector includes a CCD image sensor.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein the light detector includes a CMOS image sensor.

### Claim 13

A method for inspecting a surface of a display panel comprising:
generating detection data including distribution of light intensity from reflected light of incident light irradiated to a region of interest on a surface of the display panel;
determining a degree of curvature of the region of interest based on differences in magnitudes of data values for each coordinate between the detection data and modeling data for the region of interest; and
determining whether the display panel is defective based on the degree of curvature.

### Claim 14 (depends on 13)

The method of claim 13, wherein the modeling data includes distribution of reference light intensity for the region of interest.

### Claim 15 (depends on 14)

The method of claim 14, wherein the determining of the degree of curvature includes:
extracting, as reference coordinates, coordinates of a position corresponding to a maximum value of the light intensity included in the detection data; and
generating corrected modeling data by shifting the modeling data so that coordinates of a position corresponding to a maximum value of the reference light intensity of the modeling data coincide with the reference coordinates.

### Claim 16 (depends on 15)

The method of claim 15, wherein the determining of the degree of curvature further includes calculating differences of data values for each coordinate between the corrected modeling data and the detection data.

### Claim 17 (depends on 16)

The method of claim 16, wherein the determining of the degree of curvature further includes calculating a total sum of the differences as a representative value corresponding to the degree of curvature

### Claim 18 (depends on 17)

The method of claim 17, wherein the determining of whether the display panel is defective includes:
comparing the representative value with a threshold value;
determining that the display panel is defective in case that the representative value exceeds the threshold value; and
determining that the display panel is normal in case that the representative value is equal to or less than the threshold value.

### Claim 19 (depends on 17)

The method of claim 17, wherein the incident light is adjusted to correspond to a size of the region of interest.

### Claim 20 (depends on 17)

The method of claim 17, wherein each of the differences of data values is an absolute value of a difference between data values of corresponding coordinates between the detection data and the corrected modeling data.