Display substrate inspection method

Abstract

A display substrate inspection method includes: a step of photographing a display substrate including a plurality of cells; a step of determining cell edges of the cells based on brightness at respective positions of the display substrate; a step of setting an extended region of interest based on outermost positions in a first direction of the cell edges and outermost positions in a second direction of the cell edges; a step of determining a specific shape portion within the extended region of interest based on brightness at respective positions of the display substrate; a step of performing image processing on the specific shape portion; and a step of performing defect inspection of the display substrate with reference to the extended region of interest.

Description

Technical Field

[0001] The present invention relates to a method for inspecting a display substrate and a display substrate inspection apparatus for performing the method for inspecting a display substrate. More specifically, the present invention relates to a method for inspecting a display substrate that minimizes a non-inspected area by expanding a region of interest to the maximum, and a display substrate inspection apparatus for performing the method for inspecting a display substrate. Background Art

[0002] In the display industry, there is an ongoing struggle with production volume, and an increase in production volume is linked to price competition. Therefore, production volume is a factor that has a great impact on the manufacturing cost of display devices. In order to increase production volume, although the operation reliability of each unit process is also important, one of the most important is the inspection equipment. This is because the first choice for analyzing and improving the reasons for a decrease in production volume is the detection of defective conditions.

[0003] In the inspection of display devices, there are many inspection devices such as optical, metrology, image quality, and electrical inspection devices, and many different inspections are performed in each unit process. Among them, the optical inspection device can use a camera to microscopically inspect short circuits, open circuits, and fine particles in units of several micrometers to several tens of micrometers of pixels, and macroscopically perform inspections of large foreign objects and residual films of more than several hundred micrometers.

[0004] A factor pointed out as a disadvantage of the optical inspection device can be a non-inspected area caused by hardware constraints. If the non-inspected area where inspection is not performed becomes larger, the accuracy and reliability of the inspection may decrease.

[0005] In addition, when performing a separate inspection on a specific shape portion in a display substrate, there is a problem that the inspection time increases. Summary of the Invention

[0006] The technical problem of the present invention has been completed in view of the above-described circumstances, and an object of the present invention is to provide a method for inspecting a display substrate that minimizes a non-inspected area by expanding a region of interest to the maximum.

[0007] Another object of the present invention is to provide a display substrate inspection apparatus for performing the method for inspecting a display substrate.

[0008] An embodiment of a display substrate inspection method for achieving the above object of the present invention includes: a step of photographing a display substrate including a plurality of cells; a step of determining a cell edge of the cell based on the brightness at each position of the display substrate; a step of setting an expanded region of interest based on the outermost position in a first direction of the cell edge and the outermost position in a second direction of the cell edge; a step of determining a specific shape portion within the expanded region of interest based on the brightness at each position of the display substrate; a step of performing image processing on the specific shape portion; and a step of performing a defect inspection of the display substrate based on the expanded region of interest.

[0009] In an embodiment of the present invention, the expanded region of interest may be in a rectangular shape.

[0010] In an embodiment of the present invention, the specific shape portion may include a chamfered portion formed between a corner border of the expanded region of interest and the cell edge.

[0011] In an embodiment of the present invention, the specific shape portion may include: a notch-shaped portion that is recessed in an inner direction of the cell region at a first side of the cell edge extending in the first direction.

[0012] In an embodiment of the present invention, in the step of performing a defect inspection of the display substrate based on the expanded region of interest, a first error threshold may be set for a general inspection region, and a second error threshold larger than the first error threshold may be set for the notch-shaped portion.

[0013] In an embodiment of the present invention, the specific shape portion may include: a hole-shaped portion disposed in an inner region of the cell edge.

[0014] In an embodiment of the present invention, the hole-shaped portion may be formed in a closed curve form in the inner region of the cell edge.

[0015] In an embodiment of the present invention, in the step of performing a defect inspection of the display substrate based on the expanded region of interest, a first error threshold may be set for a general inspection region, and a third error threshold larger than the first error threshold may be set for the hole-shaped portion.

[0016] In an embodiment of the present invention, in the step of performing image processing on the specific shape portion, the brightness information of the peripheral portion adjacent to the specific shape portion may be transformed into the brightness information of the specific shape portion.

[0017] In an embodiment of the present invention, in the step of performing image processing on the specific shape portion, the average brightness of the unit can be transformed into the brightness information of the specific shape portion.

[0018] In an embodiment of the present invention, in the step of performing image processing on the specific shape portion, the predetermined reference brightness information can be transformed into the brightness information of the specific shape portion.

[0019] In an embodiment of the present invention, in the step of performing a defect inspection of the display substrate based on the expanded region of interest, a first error threshold can be set for the general inspection region, and a fourth error threshold larger than the first error threshold can be set for a first edge portion extending in the second direction at one end in the first direction of the expanded region of interest.

[0020] In an embodiment of the present invention, in the step of performing a defect inspection of the display substrate based on the expanded region of interest, a first error threshold can be set for the general inspection region, and a fifth error threshold larger than the first error threshold can be set for a second edge portion extending in the first direction at one end in the second direction of the expanded region of interest.

[0021] A display substrate inspection apparatus according to an embodiment for achieving the object of the present invention described above includes an imaging device, a unit edge determination unit, a region of interest determination unit, an image processing unit, and an inspection unit. The imaging device images a display substrate including a plurality of units. The unit edge determination unit determines the unit edge of the unit based on the brightness at each position of the display substrate. The region of interest determination unit sets an expanded region of interest based on the outermost position in the first direction of the unit edge and the outermost position in the second direction of the unit edge. The image processing unit performs image processing on a specific shape portion within the expanded region of interest determined based on the brightness at each position of the display substrate. The inspection unit performs a defect inspection of the display substrate based on the expanded region of interest.

[0022] In an embodiment of the present invention, the specific shape portion may include: a notch-shaped portion that is recessed in the inner direction of the unit region at a first side of the unit edge extending in the first direction. The inspection unit can set a first error threshold for the general inspection region, and can set a second error threshold larger than the first error threshold for the notch-shaped portion.

[0023] In an embodiment of the present invention, the specific shape portion may include: a hole-shaped portion disposed in an inner region of the edge of the unit. The inspection unit may set a first error threshold for a general inspection area, and may set a third error threshold larger than the first error threshold for the hole-shaped portion.

[0024] In an embodiment of the present invention, the image processing unit may transform the brightness information of a peripheral portion adjacent to the specific shape portion into the brightness information of the specific shape portion.

[0025] In an embodiment of the present invention, the image processing unit may transform the average brightness of the unit into the brightness information of the specific shape portion.

[0026] In an embodiment of the present invention, the inspection unit may set a first error threshold for a general inspection area, and may set a fourth error threshold larger than the first error threshold for a first edge portion extending in the second direction at one end in the first direction of the expanded attention area.

[0027] In an embodiment of the present invention, the inspection unit may set a first error threshold for a general inspection area, and may set a fifth error threshold larger than the first error threshold for a second edge portion extending in the first direction at one end in the second direction of the expanded attention area.

[0028] (Advantages of the Invention)

[0029] According to the display substrate inspection method and the display substrate inspection device as described above, the unit edge can be extracted based on the brightness at each position in the display substrate, and a rectangular-shaped expanded attention area can be set based on the outermost contour lines in the first direction and the second direction of the unit edge, thereby minimizing the non-inspected area.

[0030] In addition, the specific shape portion in the display substrate can be identified based on the brightness at each position in the display substrate, and the general inspection area and the specific shape portion can be inspected simultaneously using hierarchical inspection conditions, thereby shortening the inspection time. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram showing a display substrate inspection device according to an embodiment of the present invention.

[0032] Figure 2 is a schematic diagram showing Figure 1 a plan view of the display substrate and the units in the display substrate.

[0033] Figure 3 is a schematic diagram showing Figure 1Flowchart of a display substrate inspection method of a display substrate inspection apparatus.

[0034] Figure 4 It shows Figure 1 Block diagram of a display substrate inspection apparatus.

[0035] Figure 5 It shows Figure 1 Schematic diagram illustrating an area captured by an imaging device of a display substrate inspection apparatus.

[0036] Figure 6 It shows Figure 4 Schematic diagram of a cell edge determined by a cell edge determination unit.

[0037] Figure 7 It shows Figure 4 Schematic diagram of an expanded region of interest determined by a region of interest determination unit.

[0038] Figure 8 It shows Figure 4 Schematic diagram of the result of processing an image of a special shape portion by an image processing unit.

[0039] Figure 9 It shows Figure 4 Schematic diagram of a first edge portion to which a grading condition is applied by an inspection unit.

[0040] Figure 10 It shows Figure 4 Schematic diagram of a second edge portion to which a grading condition is applied by an inspection unit.

[0041] Figure 11 It shows Figure 4 Schematic diagram of a notch shape portion to which a grading condition is applied by an inspection unit.

[0042] Figure 12 It shows Figure 1 Schematic diagram illustrating an area captured by an imaging device of a display substrate inspection apparatus.

[0043] Figure 13 It shows Figure 4 Schematic diagram of a cell edge determined by a cell edge determination unit.

[0044] Figure 14 It shows Figure 4 Schematic diagram of an expanded region of interest determined by a region of interest determination unit.

[0045] Symbol Explanation

[0046] 100: Unit Edge Judgment Unit; 200: Region of Interest Judgment Unit; 300: Image Processing Unit; 400: Inspection Unit; C1, C2, C3: Imaging Devices; GL: Display Substrate; CL: Cell; CP: Imaging Region; CE: Cell Edge; CR1, CR2, CR3, CR4: Chamfered Portions; NT: Notch Shape Portion; ROI: Region of Interest; EROI: Expanded Region of Interest; VEP: First Edge Portion; HEP: Second Edge Portion; CH: Hole Shape Portion. Detailed Embodiment

[0047] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

[0048] In the present invention, the notch shape portion and the hole shape portion are portions where notches and holes are formed in the final product state, and the notches and the holes may not be fully formed in the mother board inspection step.

[0049] The notch shape portion may be an area where no pixel pattern is configured or an area having a pixel density different from that of a general inspection area. For example, the pixel density of the notch shape portion may be less than the pixel density of the general inspection area. For example, the notch shape portion may also be a display area for displaying an image, or may be a non-display area where no image is displayed.

[0050] The hole shape portion may be an area where no pixel pattern is configured or an area having a pixel density different from that of the general inspection area. For example, the pixel density of the hole shape portion may be less than the pixel density of the general inspection area. For example, the hole shape portion may also be a display area for displaying an image, or may be a non-display area where no image is displayed.

[0051] Figure 1 is a schematic diagram showing a display substrate inspection apparatus according to an embodiment of the present invention. Figure 2 is showing Figure 1 a plan view of the display substrate and cells within the display substrate.

[0052] Referring to Figure 1 and Figure 2 , the display substrate inspection apparatus may include a plurality of imaging devices C1, C2, C3 for imaging the display substrate GL.

[0053] For example, the display substrate GL may be a glass substrate. A plurality of cells CL may be formed in the display substrate GL.

[0054] The relative positions of the photographing devices C1, C2, and C3 and the display substrate GL are variable. For example, the photographing devices C1, C2, and C3 may be fixed, and the display substrate GL may be moved in one direction on the workbench. Differently, it may also be that the display substrate GL is fixed and the photographing devices C1, C2, and C3 are moved in one direction.

[0055] The display substrate GL can be aligned in a hardware manner using a component called a jig. The jig can be configured in a cylindrical shape near the four corners of the display substrate GL, and can guide the display substrate GL to a position corresponding to the photographing devices C1, C2, and C3.

[0056] Near the four corners, when the jig contacts the display substrate GL, the display substrate GL may be broken, so the width defined by the jig can be set to be larger than the width of the display substrate GL.

[0057] For example, in the case of defining a rectangular coordinate system, the width of the jig in the x-axis direction can be about 100 μm larger than the width of the display substrate GL in the x-axis direction. For example, the width of the jig in the y-axis direction can be about 100 μm larger than the width of the display substrate GL in the y-axis direction.

[0058] In the optical inspection of the display substrate GL, due to this interval of the jig, errors in the x-axis direction, errors in the y-axis direction, and errors in the twisted angle may occur. For example, such errors can be about 150 μm.

[0059] In addition, when the display substrate GL or the photographing devices C1, C2, and C3 are moved, errors in straightness may occur. For example, such errors can be about 10 μm.

[0060] In addition, an error of about 30 μm may occur due to the aberration of the lenses of the photographing devices C1, C2, and C3.

[0061] Due to the above-mentioned errors, the setting of the region of interest (ROI) of the optical inspection may be restricted, and the region excluded from the region of interest may become a non-inspection region.

[0062] Figure 3 is a flowchart of the display substrate inspection method of the display substrate inspection device Figure 1 shown. Figure 4 is a block diagram of the display substrate inspection device Figure 1 shown.

[0063] Refer to Figures 1 to 4, the photographing devices C1, C2, and C3 can photograph a display substrate GL including a plurality of cells CL (step S100).

[0064] The cell edge determination unit 100 can ensure the brightness of each position of the display substrate GL (step S200). The cell edge determination unit 100 can determine the cell edge of the cell based on the brightness of each position of the display substrate GL (step S300).

[0065] The region of interest determination unit 200 can set an expanded region of interest based on the outermost position in the first direction D1 of the cell edge and the outermost position in the second direction D2 of the cell edge (step S400). For example, the region of interest determination unit 200 can form a first side and a second side facing each other based on the outermost position in the first direction D1 of the cell edge, and can form a third side and a fourth side facing each other based on the outermost position in the second direction D2 of the cell edge. The expanded region of interest formed by the region of interest determination unit 200 can have a rectangular shape.

[0066] The image processing unit 300 can perform image processing on the specific shape portion in the expanded region of interest determined based on the brightness of each position of the display substrate GL (step S500).

[0067] The inspection unit 400 can perform a defect inspection of the display substrate GL based on the expanded region of interest (step S600).

[0068] Figure 5 is an example showing the region photographed by the photographing devices C1, C2, and C3 of the display substrate inspection device Figure 1 in the figure. Figure 6 is an example showing the cell edge determined by the cell edge determination unit 100 Figure 4 in the figure. Figure 7 is an example showing the expanded region of interest determined by the region of interest determination unit 200 Figure 4 in the figure. Figure 8 is an example showing the result of the image processing unit 300 processing the image of the specific shape portion Figure 4 in the figure.

[0069] In Figures 5 to 8 , a part of the region photographed by the photographing device is defined as a photographing region CP.

[0070] Referring to Figure 5 , the photographing region CP is shown as a rectangle, and the cells formed in the photographing region CP are shown by dotted lines.

[0071] Referring to Figure 6, the cell edge determination unit 100 can determine the cell edge CE of the cell CL based on the brightness at each position of the display substrate GL. The cell edge CE identifies the chamfered portions at the four corners of the cell CL based on the brightness at each position, and also identifies a notch-shaped portion that is recessed in the upward direction of the upper side of the cell CL toward the center of the cell.

[0072] In this embodiment, the internal area of the cell edge CE can be defined as a general inspection area. The notch-shaped portion can be an area where no pixel pattern is configured or an area having a pixel density different from that of the general inspection area. For example, the pixel density of the notch-shaped portion can be less than the pixel density of the general inspection area.

[0073] Refer to Figure 7 , the region of interest determination unit 200 can set an extended region of interest EROI based on the outermost position in the first direction D1 of the cell edge CE and the outermost position in the second direction D2 of the cell edge CE. A rectangle formed by expanding the leftmost side of the cell edge CE vertically, expanding the rightmost side vertically, expanding the uppermost side of the cell edge CE horizontally, and expanding the lowermost side horizontally can be the extended region of interest EROI.

[0074] In the method of the prior art, a conventional region of interest ROI was set based on the innermost position in the first direction D1 of the cell edge CE and the innermost position in the second direction D2 of the cell edge CE. In Figure 7 , the conventional region of interest ROI and the extended region of interest EROI of this embodiment are shown together.

[0075] In Figure 7 , the specific-shaped portion within the extended region of interest EROI can be determined based on the brightness at each position of the display substrate GL.

[0076] The specific-shaped portion can include chamfered portions CR1, CR2, CR3, CR4 formed between the extended region of interest EROI and the corner frame of the cell edge CE.

[0077] In addition, the specific-shaped portion can include a notch-shaped portion NT that is recessed in the inward direction of the cell region at the first side (e.g., the upper side) of the cell edge CE extending in the first direction D1. Hereinafter, for the sake of convenience of explanation, they are sometimes collectively referred to as specific-shaped portions CR1, CR2, CR3, CR4, NT.

[0078] When performing a defect inspection directly with the expanded region of interest EROI as a reference without performing image processing on the specifically shaped portions CR1, CR2, CR3, CR4, NT, since the chamfered portions CR1, CR2, CR3, CR4 and the cutout-shaped portion NT exhibit brightness that is significantly different from that of the general inspection region in terms of their characteristics, there will be a problem that the presence of the chamfered portions CR1, CR2, CR3, CR4 and the cutout-shaped portion NT is misrecognized.

[0079] That is, in the process of expanding the region of interest of the display substrate inspection apparatus to Figure 7 the expanded region of interest EROI, the specifically shaped portions CR1, CR2, CR3, CR4, NT are included in the expanded region of interest EROI, and in order not to misrecognize the presence of the specifically shaped portions CR1, CR2, CR3, CR4, NT within the expanded region of interest EROI, image processing may be required.

[0080] For example, the image processing unit 300 may transform the brightness information of the peripheral portion adjacent to the specifically shaped portions CR1, CR2, CR3, CR4, NT into the brightness information of the specifically shaped portions CR1, CR2, CR3, CR4, NT.

[0081] Differently, the image processing unit 300 may transform the average brightness of the cell CL into the brightness information of the specifically shaped portions CR1, CR2, CR3, CR4, NT.

[0082] Differently, the image processing unit 300 may transform the predetermined reference brightness information into the brightness information of the specifically shaped portions CR1, CR2, CR3, CR4, NT.

[0083] Figure 8 The expanded region of interest EROI in which image processing is performed by the image processing unit 300 is shown, and within the expanded region of interest EROI, the specifically shaped portions CR1, CR2, CR3, CR4, NT are not distinguished.

[0084] Figure 9 is a schematic diagram showing the first edge portion VEP to which the grading condition is applied by the inspection unit 400 of Figure 4 is a schematic diagram showing the second edge portion HEP to which the grading condition is applied by the inspection unit 400 of Figure 10 is a schematic diagram showing the cutout-shaped portion NT to which the grading condition is applied by the inspection unit 400 of Figure 4 is a schematic diagram showing the second edge portion HEP to which the grading condition is applied by the inspection unit 400 of Figure 11 is a schematic diagram showing the cutout-shaped portion NT to which the grading condition is applied by the inspection unit 400 of Figure 4 is a schematic diagram showing the cutout-shaped portion NT to which the grading condition is applied by the inspection unit 400 of

[0085] Refer toFigures 1 to 11 The inspection unit 400 can set classification inspection conditions according to the characteristics of each area within the unit CL, so as to inspect the expanded region of interest (EROI) simultaneously.

[0086] For example, the inspection unit 400 can set a first error threshold for the general inspection area, and can set a second error threshold larger than the first error threshold for the notch shape part NT. That is, since the notch shape part NT has different luminance characteristics from the general inspection area, the notch shape part NT can be inspected using a threshold different from that of the general inspection area. For the notch shape part NT, inspection can be performed using a lower criterion (a larger error range) than the general inspection area.

[0087] Differently, the inspection unit 400 can also exclude the notch shape part NT from the inspection area.

[0088] For example, the inspection unit 400 can set the first error threshold for the general inspection area, and can set a third error threshold larger than the first error threshold for a first edge part VEP extending along the second direction D2 at one end of the first direction D1 in the expanded region of interest (EROI).

[0089] The general inspection area can be an area where pixels of the display panel are arranged, and the first edge part VEP can be an area where a driving circuit or signal wiring is arranged. That is, since the first edge part VEP has different luminance characteristics from the general inspection area, the first edge part VEP can be inspected using a threshold different from that of the general inspection area. For the first edge part VEP, inspection can be performed using a lower criterion (a larger error range) than the general inspection area.

[0090] Differently, the inspection unit 400 can also exclude the first edge part VEP from the inspection area.

[0091] For example, the inspection unit 400 can set the first error threshold for the general inspection area, and can set a fourth error threshold larger than the first error threshold for a second edge part HEP extending along the first direction D1 at one end of the second direction D2 in the expanded region of interest (EROI).

[0092] The general inspection area may be an area where pixels of a display panel are configured, and the second edge portion HEP may be an area where a driving circuit or signal wirings are configured. That is, since the second edge portion HEP has a brightness characteristic different from that of the general inspection area, the second edge portion HEP can be inspected using a threshold different from that of the general inspection area. For the second edge portion HEP, inspection can be performed using a lower criterion (a larger error range) than the general inspection area.

[0093] Differently, the inspection unit 400 may also exclude the second edge portion HEP from the inspection area.

[0094] According to the present embodiment, a cell edge CE can be extracted based on the brightness at each position within the display substrate GL, and a rectangular-shaped expanded region of interest EROI can be set based on the outermost contour line in the first direction D1 and the outermost contour line in the second direction D2 of the cell edge CE, thereby minimizing the non-inspected area.

[0095] In addition, specific-shaped portions CR1, CR2, CR3, CR4, NT within the display substrate GL can be identified based on the brightness at each position within the display substrate GL, and the general inspection area and the specific-shaped portions CR1, CR2, CR3, CR4, NT can be inspected simultaneously using hierarchical inspection conditions to shorten the inspection time.

[0096] Figure 12 is a schematic diagram showing an example of an area photographed by a photographing device of a display substrate inspection device Figure 1 as shown. Figure 13 is a schematic diagram showing a cell edge determined by a cell edge determination unit Figure 4 as shown. Figure 14 is a schematic diagram showing an expanded region of interest determined by a region of interest determination unit Figure 4 as shown.

[0097] The display substrate inspection method and the display substrate inspection device according to the present embodiment are substantially the same as the display substrate inspection method and the display substrate inspection device Figures 1 to 11 except for the shape of cells within the display substrate, and thus, for the same or similar components, the same reference numerals are used and repeated descriptions are omitted.

[0098] Referring to Figures 1 to 4 and Figures 12 to 14 , a part of the area photographed by the photographing device is defined as a photographing area CP.

[0099] Referring to Figure 12 , the photographing area CP is shown as a rectangle, and cells formed within the photographing area CP are shown by dashed lines.

[0100] Referring to Figure 13 , the cell edge determination unit 100 can determine the cell edge CE of the cell CL based on the brightness at each position of the display substrate GL. The cell edge CE can identify the chamfered portions at the four corners of the cell CL based on the brightness at each position, and can also identify the circular hole (Hole) shaped portion CH formed in the upper part within the cell area.

[0101] In this embodiment, the area other than the hole shaped portion CH in the inner area of the cell edge CE can be defined as a general inspection area. The hole shaped portion CH can be an area where the pixel pattern is not configured or an area having a pixel density different from that of the general inspection area. For example, the pixel density of the hole shaped portion CH can be less than the pixel density of the general inspection area.

[0102] Referring to Figure 14 , the region of interest determination unit 200 can set an extended region of interest EROI based on the outermost position in the first direction D1 of the cell edge CE and the outermost position in the second direction D2 of the cell edge CE. A rectangle formed by expanding the leftmost side of the cell edge CE vertically, expanding the rightmost side vertically, expanding the uppermost side of the cell edge CE horizontally, and expanding the lowermost side horizontally can be the extended region of interest EROI.

[0103] In the prior art method, a conventional region of interest ROI was set based on the innermost position in the first direction D1 of the cell edge CE and the innermost position in the second direction D2 of the cell edge CE. The conventional region of interest ROI and the extended region of interest EROI of this embodiment are shown together in Figure 14 .

[0104] In Figure 14 , the special shaped portion within the extended region of interest EROI can be determined based on the brightness at each position of the display substrate GL.

[0105] The special shaped portion can include the chamfered portions CR1, CR2, CR3, CR4 formed between the extended region of interest EROI and the corner frame of the cell edge CE.

[0106] In addition, the special shaped portion can include the hole (Hole) shaped portion CH disposed in the inner area of the cell edge CE. The hole shaped portion CH can be an area where a camera of the display device is configured. Differently, the hole shaped portion CH can be an area where a sensor of the display device is configured.

[0107] For example, the hole-shaped portion CH may be formed in a closed curve shape in the inner region of the cell edge CE.

[0108] The inspection unit 400 may set classification inspection conditions according to the characteristics of each region in the cell CL, and thereby inspect the expanded region of interest EROI simultaneously.

[0109] For example, the inspection unit 400 may set a first error threshold for the general inspection region, and may set a second error threshold larger than the first error threshold for the hole-shaped portion CH. That is, since the hole-shaped portion CH has brightness characteristics different from those of the general inspection region, the hole-shaped portion CH may be inspected using a threshold different from that of the general inspection region. For the hole-shaped portion CH, inspection may be performed using a lower criterion (a larger error range) than the general inspection region.

[0110] Differently, the inspection unit 400 may also exclude the hole-shaped portion CH from the inspection region.

[0111] For example, the inspection unit 400 may set the first error threshold for the general inspection region, and may set a third error threshold larger than the first error threshold for a first edge portion VEP extending in the second direction D2 at one end of the first direction D1 of the expanded region of interest EROI.

[0112] Differently, the inspection unit 400 may also exclude the first edge portion VEP from the inspection region.

[0113] For example, the inspection unit 400 may set the first error threshold for the general inspection region, and may set a fourth error threshold larger than the first error threshold for a second edge portion HEP extending in the first direction D1 at one end of the second direction D2 of the expanded region of interest EROI.

[0114] Differently, the inspection unit 400 may also exclude the second edge portion HEP from the inspection region.

[0115] According to this embodiment, the cell edge CE may be extracted based on the brightness at each position in the display substrate GL, and a rectangular expanded region of interest EROI may be set based on the outermost contour lines in the first direction D1 and the second direction D2 of the cell edge CE, thereby minimizing the non-inspected region.

[0116] In addition, a specific shape portion in the display substrate GL may be identified based on the brightness at each position in the display substrate GL, and the general inspection region and the specific shape portion may be inspected simultaneously using classification inspection conditions, thereby shortening the inspection time.

[0117] (Industrial Applicability)

[0118] According to the display substrate inspection apparatus and the display substrate inspection method of the present invention described above, the non-inspection area can be minimized by expanding the region of interest of the optical inspection to the maximum.

[0119] As described above, the present invention has been described with reference to the respective embodiments. However, those skilled in the art should understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the claims.

Claims

1. A display substrate inspection method, comprising: Step of photographing a display substrate including a plurality of cells; Step of determining cell edges of the cells based on brightness at respective positions of the display substrate; Step of setting an expanded region of interest based on outermost positions in a first direction of the cell edges and outermost positions in a second direction of the cell edges; Step of determining a specific shape portion within the expanded region of interest based on brightness at respective positions of the display substrate; Step of performing image processing on the specific shape portion, wherein brightness of the specific shape portion is transformed; and Step of performing a defect inspection of the display substrate with reference to the expanded region of interest, wherein grading inspection conditions are set according to characteristics of respective regions within the cells, and the regions within the expanded region of interest that are not the specific shape portion and the specific shape portion are inspected simultaneously using the grading inspection conditions.

2. The display substrate inspection method according to claim 1, wherein, The expanded region of interest is rectangular in shape.

3. The display substrate inspection method according to claim 1, wherein, The specific shape portion includes: a chamfered portion formed between a corner frame of the expanded region of interest and the cell edge.

4. The display substrate inspection method according to claim 1, wherein, The specific shape portion includes: a cutout shape portion that is recessed in an inward direction of the cell region at a first side of the cell edge extending in the first direction.

5. The display substrate inspection method according to claim 4, wherein, In the step of performing the defect inspection of the display substrate with reference to the expanded region of interest, a first error threshold is set for a region that is not the cutout shape portion, and a second error threshold larger than the first error threshold is set for the cutout shape portion.

6. The display substrate inspection method according to claim 1, wherein, The specific shape portion includes: a hole shape portion disposed in an inner region of the cell edge.

7. The display substrate inspection method according to claim 6, wherein, The hole shape portion is formed in a closed curve shape in the inner region of the cell edge.

8. The display substrate inspection method according to claim 6, wherein, In the step of performing the defect inspection of the display substrate with reference to the expanded region of interest, a first error threshold is set for a region that is not the hole shape portion, and a third error threshold larger than the first error threshold is set for the hole shape portion.

9. The display substrate inspection method according to claim 1, wherein, In the step of performing image processing on the specific shape portion, brightness information of a peripheral portion adjacent to the specific shape portion is transformed into brightness information of the specific shape portion.

10. The display substrate inspection method according to claim 1, wherein, In the step of performing image processing on the specific shape portion, average brightness of the cell is transformed into brightness information of the specific shape portion.

11. The display substrate inspection method according to claim 1, wherein, In the step of performing image processing on the specific shape portion, predetermined reference brightness information is transformed into brightness information of the specific shape portion.

12. The display substrate inspection method according to claim 1, wherein, In the step of performing the defect inspection of the display substrate with reference to the expanded region of interest, a first error threshold is set for a region that is not a first edge portion, wherein the first edge portion extends in the second direction at one end of the expanded region of interest in the first direction, and a fourth error threshold larger than the first error threshold is set for the first edge portion.

13. The display substrate inspection method according to claim 1, wherein, In the step of performing the defect inspection of the display substrate based on the expanded region of interest, a first error threshold is set for the region other than the second edge portion, where the second edge portion extends along the first direction at one end of the expanded region of interest in the second direction, and a fifth error threshold larger than the first error threshold is set for the second edge portion.

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