KR20140075042A - Apparatus for inspecting of display panel and method thereof - Google Patents

Abstract

A method of inspecting a display panel capable of obtaining accurate position information on a defective pixel includes: forming a reference pattern on a display panel; capturing the display panel to obtain a display panel image; Obtaining a first center point coordinate of a reference pattern formed on the display panel image; And determining whether there is a defective subpixel in the display panel image and if there is the defective subpixel, obtaining the position information of the defective subpixel using the first center point coordinate of the reference pattern, And the center point coordinates indicate position information in the display panel image.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus for inspecting a display panel,

The present invention relates to a display panel inspection apparatus and a method thereof, and more particularly, to a display panel inspection apparatus and a method thereof for inspecting a pixel defect in a display panel.

2. Description of the Related Art As various portable electronic devices such as a mobile communication terminal and a notebook computer have been developed in recent years, a demand for a flat panel display device that can be applied thereto is increasing.

As such a flat panel display device, a liquid crystal display device, a plasma display panel (PDP), a field emission display device, a light emitting diode display device Research. Of these flat panel display devices, liquid crystal display devices are being applied to a variety of applications because of their advantages of mass production technology, ease of driving means, high image quality and large screen realization.

Such a liquid crystal display device includes a manufacturing process of a top plate and a bottom plate accompanying a cell formation process constituting a pixel unit, an orientation film formation and rubbing process for liquid crystal alignment, a laminating process of a top plate and a bottom plate, And a process of injecting and sealing liquid crystal, etc., may cause defects such as foreign matters, stains, cracks, and the like.

In order to inspect the defects of such a liquid crystal display device, a manufacturing process includes an inspection process of automatically inspecting the cells of the liquid crystal display device for problems such as afterimage, smear, and dim using image processing.

1 is a schematic view showing a conventional inspection apparatus.

Referring to FIG. 1, a conventional inspection apparatus includes a reference pattern generator 110, an image camera 120, an image processor 130, and a backlight unit 140.

First, the reference pattern generator 110 illuminates the liquid crystal display 10 with an inspection reference pattern arbitrarily set by the user for cell inspection of the liquid crystal display 10.

Next, the image camera 120 photographs the liquid crystal display 10 on which the inspection reference pattern is formed, and transfers the image to the image processing unit 130.

Next, the image processing unit 130 acquires an image from the image camera 120, and extracts defect information on the defective pixel through image processing. At this time, the image processing unit 130 includes the location information of the defective pixel in the defective information.

Since the image processing unit 130 does not fix the liquid crystal display device 10 to the inspection apparatus, the pixels of the liquid crystal display device 10 are not located at fixed coordinates in the acquired image. Accordingly, the image processing unit 130 calculates the position information of the pixels in the acquired image. Since the position information of the defective pixel is determined based on the image captured by the image camera 120, , Image distortion and the like, an error may occur with respect to the position information.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a display panel inspection apparatus and method capable of obtaining accurate position information on a defective pixel.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims. In addition, other features and advantages of the present invention may be newly understood through embodiments of the present invention.

According to an aspect of the present invention, there is provided a method of inspecting a display panel, the method comprising: forming a reference pattern on a display panel; capturing the display panel to obtain a display panel image; Obtaining a first center point coordinate of a reference pattern formed on the display panel image; And determining whether there is a defective pixel in the display panel image, and if the defective pixel exists, acquiring positional information of the defective pixel using the first center point coordinate of the reference pattern. The first center point coordinate indicates position information in the display panel image.

According to the present invention, by using a plurality of reference patterns, it is possible to accurately match the position information in the display panel image and the position information in the display panel.

Further, according to the present invention, the center point of the reference pattern displayed on the display panel image can be precisely extracted by using the mask filter emphasizing the center point, thereby obtaining the accurate position information on the defective pixel have.

1 is a schematic view of a conventional display panel inspection apparatus.
2 is a block diagram illustrating a display panel inspection apparatus according to an embodiment of the present invention.
3 is a diagram showing an example of a display panel image
4 is a view schematically showing an ROI area within a display panel image.
5 is a diagram illustrating an example of an ROI image generated by an ROI extraction unit.
FIG. 6 is an enlarged view of FIG. 5C.
7A is a diagram showing an ROI image subjected to image processing by binarization.
7B is a view showing an example of a mask filter.
7C is a view showing an ROI image filtered using a mask filter.
8 is a diagram showing an example in which the first center point coordinate and the second center point coordinate are matched.
9 is a diagram showing an example of a calibrated display panel image.
10 is a flowchart illustrating a method of testing a display panel according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

2 is a block diagram illustrating a display panel inspection apparatus according to an embodiment of the present invention.

The display panel inspection apparatus according to an embodiment of the present invention is an apparatus for inspecting the display panel 20 for defects. The display panel 20 may include a liquid crystal display apparatus (LCD), a plasma display panel (PDP), a field emission display device, a light emitting diode display device ) And the like, and includes all the flat panel display devices formed by the gate lines and the data lines and driven by the matrix method.

Hereinafter, for convenience of explanation, the "display panel" will be described as an example of a "liquid crystal display panel".

Although not shown in Fig. 2, the liquid crystal display panel 20 is composed of a lower substrate and an upper substrate which are adhered to each other with a liquid crystal layer interposed therebetween, and displays a predetermined image using light emitted from the backlight unit.

The pixels of the liquid crystal display panel 20 are defined by a gate line arranged in a first direction and a data line arranged to be spaced apart from each other in a second direction crossing the first direction, A thin film transistor which is a switching element is formed in the arranged region. The gate line and the data line are connected to the gate driver and the data driver, and the gate driver and the data driver are driven to display an image.

On the other hand, the liquid crystal display panel 20 receives and displays a plurality of reference patterns or inspection patterns from a pattern generating unit (not shown). The pattern generating unit (not shown) may be connected to the gate driving unit and the data driving unit, or may function as a gate driving unit and a data driving unit, and may apply a plurality of reference patterns or inspection patterns to the liquid crystal display panel 20. The plurality of reference patterns or inspection patterns displayed on the liquid crystal display panel 20 can represent the position information by (data line, gate line).

2, an apparatus for inspecting a display panel according to an exemplary embodiment of the present invention includes an imaging unit 210, an image collection unit 220, an ROI extraction unit 230, a center point coordinate acquisition unit 240, A coordinate matching unit 250, a subpixel coordinate obtaining unit 260, a defect detecting unit 270, and a display unit 280.

First, the image sensing unit 210 acquires a liquid crystal display panel image by photographing the liquid crystal display panel 20 on which the reference pattern or the inspection pattern is formed, and transmits the obtained liquid crystal display panel image to the image collection unit 220. Here, the image sensing unit 210 may include a CCD (Charge Coupled Device) camera. When the size of the LCD panel 20 is increased, it is difficult to capture an entire image with one CCD camera.

In the case of a black CCD camera, red (R), green (G), blue (B), and blue (B) colors are preferably used as the imaging unit 210. [ It is preferable to provide a color filter.

In addition, the image sensing unit 210 may be fixed, but may move relative to the liquid crystal display panel 20. To this end, the liquid crystal display panel 20 may be mounted on a stage (not shown) for X-Y driving or may be connected to a driving unit (not shown) for driving the imaging unit 210 to drive X-Y.

Next, the image collection unit 220 collects the first liquid crystal display panel image on which the reference pattern is formed, from the image pickup unit 210, and transmits the image to the ROI extraction unit 230. The image collection unit 220 collects the second liquid crystal display panel image on which the inspection pattern is formed from the image pickup unit 210 and transmits the collected image to the defect detection unit 270.

On the other hand, when the image pickup unit 210 is composed of a plurality of CCD cameras, the image collecting unit 220 collects a plurality of first liquid crystal display panel images together with camera identification information from a plurality of CCD cameras.

As shown in FIG. 3, the first liquid crystal display panel image is obtained by photographing a part of the area of the liquid crystal display panel 20, and a plurality of reference patterns are spaced apart by a pattern period.

Next, the ROI extracting unit 230 extracts a region of interest (ROI) image including the reference pattern from the first liquid crystal display panel image provided from the image collecting unit 220.

More specifically, the ROI extracting unit 230 searches a reference pattern in the first liquid crystal display panel image, and determines an area including the searched reference pattern as an ROI area. The ROI extracting unit 230 extracts the determined ROI region to generate an ROI image.

Hereinafter, the ROI image generated by the ROI extracting unit 230 will be described in more detail with reference to FIGS. 4 and 5. FIG.

4 is a view schematically showing an ROI area in the first liquid crystal display panel image. 5 is a diagram illustrating an example of an ROI image generated by an ROI extraction unit.

It is assumed that nine reference patterns are formed in the first liquid crystal display panel image, as shown in FIG.

First, the ROI extracting unit 230 searches the first reference pattern 310 in the first liquid crystal display panel image. At this time, the first reference pattern 310 searched by the ROI extracting unit 230 is used as a pattern for searching another reference pattern.

In one embodiment, the ROI extractor 230 may search the first reference pattern 310 using a pattern matching algorithm or a blob algorithm.

The ROI extractor 230 determines a certain region including the first reference pattern 310 as an ROI region when the first reference pattern 310 is searched. The ROI extracting unit 230 extracts the determined ROI region to generate a first ROI image, and provides the generated first ROI image to the center point coordinate obtaining unit 240. The first ROI image generated as described above includes the first reference pattern 310, as shown in FIG.

Next, the ROI extractor 230 receives the first center point coordinate of the first reference pattern 310 from the center point coordinate obtaining unit 240, and uses the first center point coordinate of the first reference pattern 310 The second reference pattern 320 is searched.

For example, the ROI extractor 230 may search for the second reference pattern 320 by shifting a pattern period from the first center point coordinate of the first reference pattern 310.

When the second reference pattern 320 is searched, the ROI extracting unit 230 determines a certain region including the second reference pattern 320 as an ROI region to generate a second ROI image, To the center-point coordinate acquiring unit 240.

In one embodiment, the ROI extractor 230 can simultaneously search the remaining eight reference patterns using the first center point coordinates and the pattern period of the first reference pattern 310. [

For example, assuming that the first center point coordinate of the first reference pattern 310 is (X ₁ , Y ₁ ) and the pattern period is the first distance A in the X-axis direction and the second distance B). ROI extraction unit 230 first reference eight reference pattern by using the first center point and the pattern period of the pattern (310) to _{(X 1 + A, Y 1} ), (X 1 + 2A, Y 1), _{(X 1, Y 1 + B} ), (X 1 + A, Y 1 + B), (X 1 + 2A, Y 1 + B), (X 1, Y 1 + 2B), (X 1 + A, Y ₁ 2B), (it can be predicted that the location _{X1 + 2A, Y 1 + 2B} ).

Referring again to FIG. 2, the center-point coordinate obtaining unit 240 determines a center point in the reference pattern included in the ROI image, and obtains a first center-point coordinate with respect to the determined center-point.

Here, the first center-point coordinates indicate the position information in the LCD panel image, and may be changed according to the photographing position of the liquid crystal display panel 20. This first center point coordinate can be expressed by (X, Y).

Hereinafter, for convenience of explanation, it is assumed that the center point coordinate obtaining unit 240 determines the center point of the first reference pattern 310 included in the first ROI image and acquires the first center point coordinate with respect to the determined center point Explain it.

5 is received from the ROI extracting unit 230, the center point coordinate obtaining unit 240 obtains a center point coordinate of the first reference pattern 310 included in the first ROI image using the mask filter The center point is extracted.

At this time, the center-point coordinate obtaining unit 240 filters the first ROI image using a mask filter in a predetermined unit. The predetermined unit may be any one of a pixel (Pixel P), a sub-pixel (SP), and a CCD pixel (Chargecoupled Device Pixel) as shown in FIG.

The center point coordinate obtaining unit 240 preferably performs filtering using a mask filter in units of CCD pixels (CP) to obtain more accurate coordinates with respect to the center point.

Hereinafter, for convenience of description, it is assumed that the center-point coordinate obtaining unit 240 obtains coordinates in units of CCD pixels (CP). However, the present invention is not limited thereto. In another embodiment, The coordinates may be obtained in units of subpixels (SP).

FIG. 7A is a schematic view showing a first ROI image subjected to a binarized image process, FIG. 7B is a view showing an example of a mask filter, and FIG. 7C is a view showing a first ROI image filtered using a mask filter.

First, the center-point coordinate obtaining unit 240 performs binarization processing on the first ROI image shown in FIG. 5 to obtain a binarized image as shown in FIG. 7A. The binarized image corresponds to an image in which the brightness of the CCD pixel (CP) is 0 or 1, that is, only in black or white.

Specifically, if the brightness value of the CCD pixel (CP) existing in the first ROI image is lower than the threshold value, the center-point coordinate obtaining unit 240 sets 0 to the corresponding CCD pixel (CP) The first ROI image is converted into a binary image by setting 1 in the corresponding CCD pixel CP.

In FIG. 7A, the first ROI image is converted into a binary image. However, in another embodiment, the first ROI image may be converted into a gray-scale image. The gray scale image corresponds to an image in which the brightness of the CCD pixel (CP) is expressed from 0 to 255.

Next, the center-point coordinate obtaining unit 240 filters the binary image using a mask filter in units of CCD pixels. At this time, the mask filter uses an N * N mask filter and is characterized by weighting the edges.

For example, the mask filter may be composed of a 5 * 5 filter as shown in FIG. 7B, and a weight '1' is set to a filter located at an edge, and '0' is set to a filter excluding edges . At this time, the filter may be equal to the CCD pixel (CP) size of the ROI image.

The center-point coordinate acquiring unit 240 adds the values of the CCD pixels (CP) matched with the edge filter and determines the brightness value of the CCD pixel (CP) matched with the center filter.

On the other hand, the center-point coordinate obtaining unit 240 obtains a filtered image as shown in FIG. 7C by performing filtering on all CCD pixels (CP) included in the image shown in FIG. 7A.

Next, the center-point coordinate obtaining unit 240 determines the center pixel 315 as the CCD pixel CP having the lowest brightness value in the filtered image and obtains the first center-point coordinate with respect to the center point 315.

Referring again to FIG. 2, the coordinate matching unit 250 matches the first center point coordinates obtained by the center point coordinate obtaining unit 240 with the second center point coordinates of the reference pattern displayed on the liquid crystal display panel 20.

Here, the second center point coordinates represent position information in the liquid crystal display panel 20, and have a fixed value according to the data line and gate line position applied by the pattern generating unit (not shown). This second center-point coordinate can be represented by (data line, gate line).

8 is a diagram showing an example in which the first center point coordinate and the second center point coordinate are matched.

8, when the center point coordinate obtaining unit 240 obtains the first center point coordinates of the reference pattern displayed on the first liquid crystal display panel image, the coordinate matching unit 250 reads the obtained first center point coordinates Is matched with the second center point coordinates of the reference pattern displayed on the liquid crystal display panel 20 and is stored.

When a plurality of reference patterns are formed on the first liquid crystal display panel image, the coordinate matching unit 250 stores the first center point coordinates and the second center point coordinates by matching each reference pattern on a one-to-one basis.

2, the sub pixel coordinate obtaining unit 260 obtains the first center point coordinates of the subpixel SP using the first center point coordinates of the reference pattern obtained by the center point coordinate obtaining unit 240 .

Specifically, the subpixel coordinate acquisition unit 260 acquires the first reference pattern 310 and the second reference pattern 310 using the first center point coordinate of the first reference pattern 310 and the first center point coordinate of the second reference pattern 320, The distance and angle between the two reference patterns 320 are calculated. The subpixel coordinate acquisition unit 260 calculates the subpixel coordinates of at least one subpixel SP formed between the first reference pattern 310 and the second reference pattern 320 using the calculated distances and angles. 1 Calculate the center point coordinates.

9 shows an image obtained by calibrating the image of the first liquid crystal display panel using the coordinates of a plurality of subpixels obtained by the subpixel coordinate obtaining unit 260. As shown in FIG. In the calibration image shown in FIG. 9, the coordinates of the first center point of the R subpixels are indicated by white dots.

Next, the defect detection unit 270 determines whether the liquid crystal display panel 20 is defective based on the second liquid crystal display panel image transmitted from the image collection unit 220, and detects a defective pixel. At this time, an inspection pattern is formed on the second liquid crystal display panel image transmitted from the image collection unit 220.

For example, when a black signal is applied to the entire screen of the liquid crystal display panel 20 as an inspection pattern, the defect detector 270 determines whether or not a pixel P or a subpixel SP appearing bright rather than a black signal exists The contrast can be compared to judge whether the defect is defective or not. At this time, the defect detector 270 generates defect information when a defect is detected.

Here, the defect information includes at least one of whether or not a defect has occurred, the kind of defect, the degree of defect, and the position information of the sub-pixel (or pixel) where the defect has occurred.

In order to generate the positional information of the defective sub-pixel, the defect detector 270 identifies the first center-point coordinate of the defective sub-pixel and outputs the first center-point coordinate as the second center-point coordinate through the coordinate-matching unit 250 Conversion. Then, the defect detector 270 generates defect information based on the coordinates of the second center point of the defective subpixel.

Next, the display unit 280 displays the second liquid crystal display panel image photographed by the imaging unit 210 and the defect information.

In FIG. 2, the defect detector 270 acquires the second liquid crystal display panel image separately from the first liquid crystal display panel image to detect defective pixels. However, in another embodiment, It is possible to determine whether or not the liquid crystal display panel is defective and to detect defective pixels.

10 is a flowchart illustrating a method of testing a display panel according to an embodiment of the present invention.

Referring to FIG. 10, first, the display panel inspection apparatus forms a reference pattern on the display panel 20, and then captures the display panel 20 to obtain a first display panel image (S1001). The pattern generating unit (not shown) may be connected to the gate driver and the data driver of the display panel 20 to apply a plurality of reference patterns to the display panel 20.

The display panel inspection apparatus captures the first display panel image by photographing the display panel 20 when a plurality of reference patterns are applied to the display panel 20 by a pattern generating unit (not shown).

Next, the display panel inspection apparatus obtains the first center point coordinates of the reference pattern (S1002). Hereinafter, a method of obtaining the coordinates of the first center point of the reference pattern will be described in more detail with reference to FIG.

11 is a flow chart illustrating one embodiment of a method of obtaining a first center point coordinate of a reference pattern.

Referring to FIG. 11, first, the display panel inspection apparatus searches for a first reference pattern in a display panel image (S1101). At this time, the first reference pattern may be utilized as a pattern for searching another reference pattern.

In one embodiment, the display panel inspection apparatus may search the first reference pattern 310 using a pattern matching algorithm or a blob algorithm.

Next, when the first reference pattern is searched, the display panel inspection apparatus determines a certain region including the first reference pattern as an ROI region, extracts the determined ROI region, and generates a first ROI image (S1102).

Next, the display panel inspection apparatus determines the center point of the first reference pattern included in the first ROI image (S1103).

More specifically, the display panel inspection apparatus filters the first ROI image using a mask filter in units of CCD pixels. At this time, the mask filter uses an N * N mask filter and is characterized by weighting the edges.

For example, the mask filter may be composed of a 5 * 5 filter, and a weight '1' may be set to a filter positioned at the edge, and '0' may be set to the remaining filters except for the edge. At this time, the filter may be equal to the CCD pixel (CP) size of the ROI image.

The display panel inspection apparatus determines the brightness value of the CCD pixel (CP) matched with the center filter by summing the values of the CCD pixels (CP) matched with the edge filter. Then, the display panel inspection apparatus performs filtering on all the CCD pixels included in the first ROI image, and determines the CCD pixel having the lowest brightness value as the center point of the first reference pattern.

Next, the display panel inspection apparatus acquires the first center point coordinates of the determined center point (S1104).

Next, the display panel inspection apparatus moves the ROI region by a pattern period from the first center point coordinate of the first reference pattern, and generates a second ROI image based on the extracted ROI region (S1105 and S1106).

Next, the display panel inspection apparatus determines the center point of the second reference pattern included in the second ROI image, and obtains the first center point coordinate of the determined center point (S1107 and S1108).

The display panel inspection apparatus repeats S1106 to S1108 for all the reference patterns included in the first display panel image.

Next, the display panel inspection apparatus stores the first center point coordinates for each of the plurality of reference patterns with the second center point coordinates (S1110).

Here, the first center point coordinate indicates position information in the display panel image, and may be changed depending on the photographing position of the display panel 20. [ This first center point coordinate can be expressed by (X, Y).

On the other hand, the second center point coordinates indicate position information in the display panel, and have a fixed value according to the data line and gate line position applied by the pattern generating unit (not shown). This second center-point coordinate can be represented by (data line, gate line).

In FIG. 11, the first center point coordinates for a plurality of reference patterns are sequentially obtained. However, in another embodiment, the first center point coordinates of the first reference pattern are used to obtain the first center point coordinates May be acquired at the same time.

More specifically, the display panel inspection apparatus can simultaneously search the remaining reference patterns using the first center point coordinates and the pattern period of the first reference pattern, and simultaneously generate a plurality of ROI images including the reference patterns have.

Referring again to Fig. 10, the display panel inspection apparatus acquires the first center point coordinates of the subpixel (S1003). Specifically, the display panel inspection apparatus obtains the first center-point coordinates of the subpixel using the first center-point coordinates of the plurality of reference patterns.

For example, the display panel inspection apparatus calculates the distance and the angle between the first reference pattern and the second reference pattern using the first center point coordinate of the first reference pattern and the second center point coordinate of the second reference pattern . The display panel inspection apparatus can calculate the first center point coordinates of at least one subpixel formed between the first reference pattern and the second reference pattern by using the calculated distances and angles.

Next, the display panel inspection apparatus forms an inspection pattern on the display panel 20, and then captures the display panel 20 to acquire the second display panel image (S1004). The pattern generator (not shown) may be connected to the gate driver and the data driver of the display panel 20 to apply a test pattern to the display panel 20.

When the inspection pattern is applied to the display panel 20 by the pattern generating unit (not shown), the display panel inspection apparatus captures the display panel 20 to acquire the second display panel image.

Next, the display panel inspection apparatus determines whether or not the display panel is defective based on the second display panel image, and detects a defective pixel (S1005).

For example, when the pattern generating unit (not shown) applies a black signal to the display panel 20 as an inspection pattern, the display panel inspecting apparatus determines whether there is a pixel or subpixel that appears bright instead of a black signal, .

Next, the display panel inspection apparatus confirms the coordinates of the first center point of the defective pixel (S1006), and converts the identified first center point coordinate into the second center point coordinate (S1007).

Next, the display panel inspection apparatus generates position information on the defective pixel based on the coordinates of the second center point of the defective pixel, and displays the defective information (S1008).

In FIG. 10, the display panel inspection apparatus acquires the second display panel image separately from the first display panel image for defective pixel detection. However, in another embodiment, the defective display panel image , And may detect a defective pixel.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

20: display panel 210:
220: image collecting unit 230: ROI extracting unit
240: Center point coordinate acquiring unit 250: Coordinate matching unit
260: Subpixel coordinate acquisition unit 270:
280:

Claims (10)

Forming a reference pattern on a display panel and photographing the display panel to obtain a display panel image;
Obtaining a first center point coordinate of a reference pattern formed on the display panel image; And
Determining whether there is a defective subpixel in the display panel image and obtaining the position information of the defective subpixel using the first center point coordinate of the reference pattern if the defective subpixel is present,
Wherein the first center point coordinate indicates position information in the display panel image. The method according to claim 1,
Wherein the reference pattern includes a first reference pattern and a second reference pattern spaced apart from the first reference pattern by a pattern period,
Wherein the obtaining of the first center-
Obtaining a first center point coordinate of the first reference pattern formed on the display panel image; And
And obtaining the first center point coordinates of the second reference pattern using the first center point coordinates and the pattern period of the obtained first reference pattern. 3. The method of claim 2, wherein obtaining the second center point coordinate of the first reference pattern comprises:
Searching the first reference pattern from the display panel image;
Extracting a region of interest (ROI) region including the searched first reference pattern to generate a first ROI image; And
And obtaining a first center point coordinate of a first reference pattern from the generated first ROI image. 4. The method of claim 3, wherein the searching for the first reference pattern comprises:
Wherein the first reference pattern is searched using a pattern matching algorithm or a blob algorithm. 3. The method of claim 2, wherein obtaining the first center point coordinates of the second reference pattern comprises:
Extracting an ROI region by the pattern period from a first center point coordinate of the first reference pattern, and generating a second ROI image based on the extracted ROI region; And
And obtaining a first center point coordinate of a second reference pattern from the generated second ROI image. 2. The method of claim 1, wherein obtaining the first center-
Filtering the ROI image including the reference pattern using a mask filter in units of CCD pixels; And
Determining a CCD pixel having the smallest brightness value as a center point of the reference pattern and obtaining a first center point coordinate of the determined center point. The method according to claim 6,
Wherein the mask filter is composed of an N * N filter, the filter coefficient of the filter located at the edge is set to 1, and the filter coefficient of the remaining filters excluding the edge is set to zero. The method according to claim 1,
Further comprising the step of matching a first center point coordinate of the reference pattern with a second center point coordinate of the reference pattern,
And the second center point coordinates indicate position information on the display panel. The method according to claim 1,
Wherein the reference pattern includes a first reference pattern and a second reference pattern spaced apart from the first reference pattern by a pattern period,
A first center point coordinate of at least one subpixel formed in the first reference pattern and a second reference pattern using the first center point coordinate of the first reference pattern and the first center point coordinate of the second reference pattern, The method further comprising the step of: 10. The method of claim 9, wherein obtaining the location information of the defective sub-
Determining a first center point coordinate of the defective subpixel and converting a first center point coordinate of the identified defective subpixel to a second center point coordinate,
And the second center point coordinates indicate position information on the display panel.

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