# US 12,217,721 B2 · Mura inspection device for compressing mura data through dimensionality reduction, operating method, and display system including the same

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- Number: US 12,217,721 B2
- Document ID: US12217721B2
- Status: Granted
- Kind: B2
- Application number: 17/953,624
- Filed: 2022-09-27
- Published: 2023-05-11
- Granted: 2025-02-04
- Earliest claimed: 2021-11-11
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Pil-Seung Heo; Se Whan Na
- Web page: https://patentgrep.com/patent/US12217721B2

## CPC

- G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters}
- G09G 5/003: {Details of a display terminal, the details relating to the control arrangement of the display terminal and to the interfaces thereto (specific for a CRT G09G1/165; for a flat panel G09G3/2092)}
- G09G 2300/0465: Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/029: by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
- G09G 2330/10: Dealing with defective pixels
- G09G 2360/141: the light conveying information used for selecting or modulating the light emitting or modulating element
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

A mura inspection device may include; an optical meter configured to measure luminance of a display region and generate a first luminance matrix, a luminance preprocessor configured to detect a distortion region of the display region in relation to the first luminance matrix, and generate a second luminance matrix by adjusting luminance of the distortion region, a mura generator configured to generate a mura matrix in relation to a difference between the second luminance matrix and a reference value, and an encoder configured to generate encoding data by applying dimensionality reduction to the mura matrix.

## Claims

### Claim 1

A mura inspection device comprising:
an optical meter configured to measure luminance of a display region and generate a first luminance matrix;
a luminance preprocessor configured to detect a distortion region of the display region in relation to the first luminance matrix, and generate a second luminance matrix by adjusting luminance of the distortion region;
a mura generator configured to generate a mura matrix in relation to a difference between the second luminance matrix and a reference value; and
an encoder configured to generate encoding data by applying dimensionality reduction to the mura matrix,
wherein the first luminance matrix includes a plurality of first elements respectively having a plurality of raw luminance values, and the luminance preprocessor is further configured to identify a first element among the plurality of first elements as a distorted element of the first luminance matrix corresponding to the distortion region, the identified first element having a raw luminance value less than a first luminance value,
wherein when the raw luminance value of the distorted element is greater than or equal to a second luminance value less than the first luminance value, the luminance preprocessor is further configured to
calculate an average luminance value of a column including the distorted element,
calculate a convergence luminance value of the plurality of first elements, and
determine a pre-processed luminance value corresponding to a distorted element in the second luminance matrix in relation to a difference between the average luminance value and the convergence luminance value, and
wherein the distorted element in the second luminance matrix corresponds to the distorted element of the first luminance matrix.

### Claim 2 (depends on 1)

The mura inspection device of claim 1, wherein when the raw luminance value of the distorted element is less than the second luminance value, the luminance preprocessor is further configured to:
determine a luminance tendency for the first elements adjacent to the distorted element; and
determine a pre-processed luminance value corresponding to a distorted element in the second luminance matrix in relation to the luminance tendency,
wherein the distorted element of the second luminance matrix corresponds to the distorted element of the first luminance matrix.

### Claim 3 (depends on 1)

The mura inspection device of claim 1, wherein the luminance preprocessor is further configured to:
identify another first element among the first elements as a normal element of the first luminance matrix, the other first element having a raw luminance value greater than or equal to the first luminance value; and
determine a pre-processed luminance value corresponding to a normal element of the second luminance matrix as the raw luminance value of the normal element of the first luminance matrix,
wherein the normal element in the second luminance matrix corresponds to the normal element of the first luminance matrix.

### Claim 4 (depends on 1)

The mura inspection device of claim 1, wherein a first luminance similarity between the distortion region and a normal region in the second luminance matrix is greater than a second luminance similarity between the distortion region and a normal region in the first luminance matrix.

### Claim 5 (depends on 1)

The mura inspection device of claim 1, wherein a size of the encoding data is less than a size of data generated by applying a lossy compression to the mura matrix.

### Claim 6 (depends on 1)

The mura inspection device of claim 1, wherein the encoder is further configured to communicate the encoding data to a display driving integrated circuit controlling the display region.

### Claim 7 (depends on 1)

The mura inspection device of claim 1, wherein applying dimensionality reduction to mura data of the mura matrix comprises determining a principal component vector in relation to vectors corresponding to the mura data, and determining at least one sub-vector in relation to the principal component vector and the vectors, and wherein the encoding data includes the principal component vector and the at least one sub-vector.

### Claim 8

A display system comprising:
a display device including a display region; and
a mura inspection device,
wherein the mura inspection device is configured to:
measure luminance of the display region to generate a first luminance matrix including a plurality of first elements respectively having a plurality of raw luminance values;
detect a distortion region of the display region in relation to the first luminance matrix;
adjust luminance of the distortion region to generate a second luminance matrix;
generate a mura matrix in relation to a difference between the second luminance matrix and a reference value;
generate encoding data by applying dimensionality reduction to the mura matrix; and
communicate the encoding data to the display device,
wherein the mura inspection device is further configured to identify a first element among the plurality of first elements as a distorted element of the first luminance matrix corresponding to the distortion region, the identified first element having a raw luminance value less than a first luminance value,
wherein, when the raw luminance value of the distorted element of the first luminance matrix is greater than or equal to a second luminance value less than the first luminance value, the mura inspection device is further configured to
calculate an average luminance value of a column including the distorted element of the first luminance matrix,
calculate a convergence luminance value for the plurality of first elements, and
determine a pre-processed luminance value corresponding to a distorted element of the second luminance matrix in relation to a difference between the average luminance value and the convergence luminance value, and
wherein the distorted element of the second luminance matrix corresponds to the distorted element of the first luminance matrix.

### Claim 9 (depends on 8)

The display system of claim 8, wherein, when the raw luminance value of the distorted element of the first luminance matrix is less than the second luminance value, the mura inspection device is further configured to:
determine a luminance tendency of a first element adjacent to the distorted element of the first luminance matrix; and
determine a pre-processed luminance value corresponding to a distorted element of the second luminance matrix in relation to the luminance tendency,
wherein the distorted element of the second luminance matrix corresponds to the distorted element of the first luminance matrix.

### Claim 10 (depends on 8)

The display system of claim 8, wherein the display device is configured to:
recover a dimension of the encoding data to generate a plurality of decoding mura values;
determine one decoding mura value among the plurality of decoding mura values corresponding to the distorted element of the second luminance matrix in relation to location information of the distorted element of the second luminance matrix; and
perform a correlation operation on the one decoding mura value to generate a correlation mura value,
wherein the correlation mura value corresponds to a mura value generated in relation to a raw luminance value corresponding to the distorted element of the first luminance matrix corresponding to the distorted element of the second luminance matrix.

### Claim 11 (depends on 8)

The display system of claim 8, wherein a first luminance similarity between the distortion region and a normal region of the second luminance matrix is greater than a second luminance similarity between the distortion region and a normal region of the first luminance matrix.

### Claim 12 (depends on 8)

The display system of claim 8, wherein the display device is configured to:
recover a dimension of the encoding data to generate a decoding mura matrix including decoding mura values; and
compensate for luminance of the display region in relation to the decoding mura matrix.

### Claim 13 (depends on 8)

The display system of claim 8, wherein applying dimensionality reduction to mura data of the mura matrix comprises determining a principal component vector in relation to vectors corresponding to the mura data, and determining at least one sub-vector in relation to the principal component vector and the vectors, and wherein the encoding data includes the principal component vector and the at least one sub-vector.

### Claim 14

A method of operating a mura inspection device measuring luminance of a display region, the method comprising:
generating a first luminance matrix of the display region, wherein the first luminance matrix includes a plurality of first elements respectively having, a plurality of raw luminance values;
detecting a distortion region of the display region in relation to the first luminance matrix;
adjusting a luminance of the distortion region to generate a second luminance matrix;
generating a mura matrix in relation to a difference between the second luminance matrix and a reference value;
generating encoding data by applying dimensionality reduction to the mura matrix;
wherein the detecting comprises identifying a first element among the plurality of first elements as a distorted element of the first luminance matrix corresponding to the distortion region, the identified first element having a raw luminance value less than a first luminance value,
wherein, when the raw luminance value of the distorted element of the first luminance matrix is greater than or equal to a second luminance value less than the first luminance value, the method further comprises
calculating an average luminance value of a column including the distorted element of the first luminance matrix,
calculating a convergence luminance value for the plurality of first elements, and
determining a pre-processed luminance value corresponding to a distorted element of the second luminance matrix in relation to a difference between the average luminance value and the convergence luminance value, and
wherein the distorted element of the second luminance matrix corresponds to the distorted element of the first luminance matrix.

### Claim 15 (depends on 14)

The method of claim 14, wherein a first luminance similarity between the distortion region and a normal region of the second luminance matrix is greater than a second luminance similarity between the distortion region and a normal region of the first luminance matrix.

### Claim 16 (depends on 14)

The method of claim 14, further comprising:
communicating the encoding data to a display driving integrated circuit controlling the display region.

### Claim 17 (depends on 14)

The method of claim 14, wherein applying dimensionality reduction to mura data of the mura matrix comprises determining a principal component vector in relation to vectors corresponding to the mura data, and determining at least one sub-vector in relation to the principal component vector and the vectors, and wherein the encoding data includes the principal component vector and the at least one sub-vector.