LINEAR DEFECT INSPECTION DEVICE

Abstract

The present disclosure relates to a defect inspection device including: an imaging part that captures an image of a first frame having a predetermined width and a predetermined length along a width direction and a length direction of a test object, respectively; an image division part that divides the image of the first frame of the test object captured by the imaging part into a plurality of second frames smaller than the first frame along the width direction of the test object; a brightness calculation part that measures a brightness value of each of the plurality of the second frames, and calculates a defect determination value of the first frame based on the brightness values of the plurality of the second frames; and a control part that determines a line defect existing along the length direction of the test object based on the calculated defect determination value of the first frame.

Claims

1. A defect inspection device comprising: an imaging part that captures an image of a first frame having a predetermined width and a predetermined length along a width direction and a length directions of a test object, respectively; an image division part that divides the image of the first frame of the test object captured by the imaging part into a plurality of second frames smaller than the first frame along the width direction of the test object; a brightness calculation part that measures a brightness value of each of the plurality of the second frames, and calculates a defect determination value of the first frame based on the brightness values of the plurality of the second frames; and a control part that determines a line defect existing along the length direction of the test object based on the calculated defect determination value of the first frame.

2. The defect inspection device according to claim 1, wherein the brightness calculation part calculates a sum of brightness values of a plurality of pixels along the length direction of one of the plurality of the second frames at a predetermined position along the width direction of the test object, and calculates the defect determination value of the first frame based on the sum of the brightness values.

3. The defect inspection device according to claim 2, wherein the image division part divides the first frame into N second frames along the width direction of the test object, wherein N is a natural number greater than 1, wherein the brightness calculation part calculates the defect determination value of the first frame based on the brightness value of each of the N second frames and the sum of the brightness values of the plurality of pixels along the length direction of the second frames in a predetermined K column along the width direction of the test object, and wherein K is a natural number less than or equal to N.

4. The defect inspection device according to claim 3, wherein the brightness calculation part calculates the defect determination value of the first frame based on a difference between a maximum value and an average value of the sum of brightness values of the plurality of pixels along the length direction of the second frames in a predetermined column along the width direction of the test object.

5. The defect inspection device according to claim 3, wherein the imaging part captures a plurality of the first frames along the length direction of the test object, and wherein the defect inspection device further comprises an image merging part that sequentially positions, in the brightness calculation part, the plurality of the first frames, in which the defect determination values are set, along the length direction of the test object to generate at least a partial image of the entire image of the test object.

6. The defect inspection device according to claim 5, wherein the control part determines line stains based on each of the defect determination values of the plurality of the first frames arranged along the width direction of the test object, and a sum of the defect determination values of the plurality of the first frames along the length direction in a predetermined column along the width direction of the test object.

7. The defect inspection device according to claim 6, wherein the control part calculates a brightness reference value of the first frame for determining the line stain based on the difference between a maximum value and an average value of the sum of the defect determination values for the plurality of the first frames along the length direction in the predetermined column along the width direction of the test object.

8. The defect inspection device according to claim 7, wherein the control part calculates the brightness reference value of the first frame for determining the line stain based on a value obtained by dividing the difference between the maximum value and the average value of the sum of the defect determination values for the plurality of the first frames along the length direction in the predetermined column along the width direction of the test object by the number of the plurality of first frames arranged along the length direction in the predetermined column.

9. The defect inspection device according to claim 8, wherein the control part determines that the line stain is included in the first frame of the test object when the defect determination value is greater than the brightness reference value of the first frame.

10. The optical member defect inspection device according to claim 9, further comprising: a display part for displaying the line stain determined by the control part on the test object.

11. The defect inspection device according to claim 1, wherein the imaging part comprises a plurality of cameras arranged along the length direction of the test object and arranged to capture a plurality of the first frames at different positions, respectively.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a schematic diagram for explaining a conventional line stain determination method.

[0027] FIG. 2 is a schematic diagram illustrating a defect inspection device related to one example of the present invention.

[0028] FIG. 3 is a configuration diagram illustrating a defect inspection device related to one example of the present invention.

[0029] FIGS. 4 to 7 are schematic diagrams for explaining an inspection method of a defect inspection device of an optical member related to one example of the present invention.

DETAILED DESCRIPTION

[0030] Hereinafter, a defect inspection device according to one example of the present invention will be described in detail with reference to the accompanying drawings.

[0031] In addition, regardless of the reference numerals, the same or corresponding components are given the same or similar reference numbers, and duplicate descriptions thereof will be omitted, and the size and shape of each component shown for convenience of description can be exaggerated or reduced.

[0032] In this document, the test object of the bonding inspection device may comprise a web or a base material on a roll-to-roll process, and in particular, the defect inspection device related to one example of the present invention may be a defect inspection device of an optical member for detecting a line stain existing along the length direction in an optical member such as a polarization plate.

[0033] In this document, the test object may be referred to as an optical member or a polarization plate.

[0034] FIG. 2 is a schematic diagram illustrating a defect inspection device (100) of an optical member related to one example of the present invention, and FIG. 3 is a configuration diagram illustrating a defect inspection device of an optical member related to one example of the present invention.

[0035] In addition, FIGS. 4 to 7 are schematic diagrams for explaining an inspection method of a defect inspection device of an optical member related to one example of the present invention.

[0036] In this document, the optical member (or also referred to as a fabric) may be, for example, a polarization plate, including an optical film, and in FIGS. 4 to 7, a polarization plate will be described as an example. In addition, the line defect (LD) means a defect that occurs above a predetermined length along the traveling direction (y-axis direction) when the optical member (200) is inspected. That is, in this document, it is possible to detect the length (length along the traveling direction of the optical member) that a linear defect occurring along the traveling direction exceeds one frame. That is, when defects are each determined from two or more frames successively along the traveling direction, the relevant defects are determined as a linear defect. In this document, the traveling direction (y-axis direction) of the optical member (or ‘test object’ or ‘fabric’) is referred to as the length direction, and the direction orthogonal to the traveling direction is referred to as the width direction (x-axis direction) of the fabric.

[0037] Referring to FIGS. 2 and 3, the optical member defect inspection device (100) (hereinafter abbreviated as inspection device) comprises an imaging part (101), an image division part (130), a brightness calculation part (120), and a control part (150).

[0038] The inspection device (100) comprises an imaging part (101) disposed to photograph a first frame (201) having a first size determined by a predetermined width and a predetermined length along the width direction (x-axis direction) and the length direction (y-axis direction) of the optical member (200). The first frame (201) may comprise a plurality of pixels, and for example, the first frame (201) may comprise A pixels in the width direction and B pixels in the length direction (total: A*B pixels). For example, A may be 4096 and B may be 2048. For example, the first frame (201) may have a length of 198 mm in the length direction.

[0039] Referring to FIGS. 2 and 3, the imaging part (101) may comprise a plurality of cameras (110) arranged along the width direction of the optical member, and arranged to photograph the first frame at different positions, respectively. In FIG. 2, an unexplained reference numeral 111 denotes encoders connected to the respective cameras (110).

[0040] Referring to FIGS. 3 and 5, the inspection device (100) comprises an image division part (130) that divides the image of the first frame (201) of the optical member (200) photographed by the imaging part (101) into images of a plurality of second frames smaller than the first frame along the width direction (x-axis direction) of the optical member.

[0041] Also, the inspection device (100) comprises a brightness calculation part (120) provided to measure brightness values of the respective second frames (202), thereby calculating a defect determination value of the first frame (201).

[0042] In addition, the inspection device (100) comprises a control part (150) provided to determine a line defect existing along the length direction (y-axis direction) of the optical member based on the calculated defect determination value of the first frame (201).

[0043] Referring to FIGS. 4 to 7, the brightness calculation part (120) may be provided to calculate a sum of brightness values of a plurality (e.g., B) of pixels along the length direction of the second frame (202) at a predetermined position along the width direction (x-axis direction) of the optical member, thereby calculating the defect determination value of the first frame (201) based on the calculated sum of the brightness values.

[0044] Specifically, the image division part (130) may divide the first frame (201) into N (N is a natural number greater than 1, for example, 128) second frames (202) along the width direction of the optical member.

[0045] At this time, the brightness calculation part (120) may calculate, based on the respective brightness values for the N second frames, the defect determination value of the first frame on the basis of the sum of brightness values of a plurality of pixels along the length direction of the second frames in a predetermined K column (K is a natural number less than or equal to N) along the width direction of the optical member.

[0046] Also, the brightness calculation part (120) may calculate, based on the difference between the maximum value and the average value of sums of brightness values of a plurality of pixels along the length direction of the second frames (202) in a predetermined column along the width direction of the optical member, the defect determination value of the first frame.

[0047] Furthermore, the imaging part (101) is provided to photograph a plurality of first frames (201), respectively, along the length direction of the optical member.

[0048] In addition, the inspection device (100) may comprise an image merging part (140) that sequentially positions and merges, in the brightness calculation part (120), the first frames (201), in which the defect determination values are set, along the length direction of the optical member to generate at least a partial image of the entire image of the optical member.

[0049] Also, the control part may determine, based on the respective defect determination values for a plurality of first frames arranged along the width direction of the optical member, line stains on the basis of the sum of the defect determination values of the plurality of the first frames along the length direction in a predetermined column along the width direction of the optical member.

[0050] Furthermore, the control part may calculate, based on the difference between the maximum value and the average value of sums of defect determination values for a plurality of first frames along the length direction in a predetermined column along the width direction of the optical member, the brightness reference value of the first frame for determining the line stain.

[0051] In addition, the control part may calculate, based on the value obtained by dividing the difference between the maximum value and the average value of sums of defect determination values for a plurality of first frames along the length direction in a predetermined column along the width direction of the optical member by the number (for example, 70) of the plurality of first frames arranged along the length direction in the predetermined column, the brightness reference value of the first frame for determining the line stain.

[0052] In addition, the control part (150) may determine the first frame of the optical member having a defect determination value greater than the brightness reference value of the first frame as a line stain.

[0053] Also, the inspection device (100) may further comprise a display part (160) for displaying the line stain determined by the control part on the optical member.

[0054] Referring to FIG. 4, the first frame (201) may comprise 4096 pixels (A) in the width direction and 2048 pixels (B) in the length direction. At this time, the first frame (201) may be divided into 128 (N) second frames (202) along the width direction (x-axis direction) of the optical member. At this time, the second frame may have A/N, that is, 32 lines (vertical lines, y-axis direction).

[0055] At this time, the brightness calculation part (120) may calculate, based on the respective brightness values for the 128 second frames, the defect determination value of the first frame on the basis of the sum of brightness values of a plurality of pixels along the length direction of the second frames in a predetermined K column (K is a natural number less than or equal to N) along the width direction of the optical member, and may also calculate, based on the difference between the maximum value and the average value of sums of brightness values of a plurality (2048) of pixels along the length direction of the second frames (202) in a predetermined column along the width direction of the optical member, the defect determination value of the first frame (201).

[0056] The imaging part is provided to photograph the first frame for a plurality of regions (not overlapping) of the optical member, respectively, that are continuous along the traveling direction of the optical member. At this time, the respective regions do not overlap, and no space is generated between two adjacent regions. That is, the imaging part photographs the entire region of the optical member in units of the first frame along the traveling direction of the optical member.

[0057] In addition, referring to FIGS. 6 and 7, a plurality of first frames (201) are each photographed along the length direction of the optical member, where the inspection device (100) may sequentially position and merge, in the brightness calculation part (120), the first frames (201) (divided images), in which the defect determination values are set, by a predetermined number (e.g., C=70, 70 frames) along the length direction of the optical member to generate at least some merged images of the entire image of the optical member.

[0058] Also, the control part may determine, based on the respective defect determination values for a plurality of first frames (202) arranged along the width direction of the optical member, line stains on the basis of the sum of the defect determination values of the plurality of the first frames along the length direction in a predetermined column along the width direction of the optical member.

[0059] Furthermore, the control part may calculate, based on the difference between the maximum value and the average value of sums of defect determination values for a plurality of first frames along the length direction in a predetermined column along the width direction of the optical member, the brightness reference value of the first frame for determining the line stain.

[0060] In addition, the control part may calculate, based on the value obtained by dividing the difference between the maximum value and the average value of sums of defect determination values for a plurality of first frames along the length direction in a predetermined column along the width direction of the optical member by the number of the plurality of first frames arranged along the length direction in the predetermined column, the brightness reference value of the first frame for determining the line stain.

[0061] In addition, it may determine the first frame of the optical member having a defect determination value greater than the brightness reference value of the first frame as a line stain.

[0062] The preferred examples of the present invention as described above are disclosed for the purpose of illustration, and various modifications, changes and additions can be made by those skilled in the art having ordinary knowledge of the present invention within the spirit and scope of the present invention, and such modifications, changes and additions shall be deemed to fall within the scope of the following claims.

INDUSTRIAL APPLICABILITY

[0063] According to the defect inspection device related to at least one example of the present invention, defect images can be stored for a long time with a low capacity, and line stain property defects can be determined by comparing the entire image of the test object.