JP2005165097A - Polarizing plate sticking position inspecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automate an inspection step of a polarizing plate sticking position. <P>SOLUTION: An L-shaped bar illumination 9 and an infrared transmission illumination 10 are arranged. The corner part C1 of a liquid crystal panel 100 is illuminated with red light of the L-shaped bar illumination 9 from just beside. The corner part C1 of the liquid crystal panel 100 is illuminated with infrared light of the infrared transmission illumination 10 from just beneath. The corner part C1 of the liquid crystal panel 100 is picked up by a camera 11 from just above, and it is judged whether or not the polarizing plate 6 is stuck on a normal position based on the position of the edge of the polarizing plate 6 appearing in the picked up image with the illumination by the L-shaped bar illumination 9 and the position of a BM pattern appearing in the picked up image with the illumination by the infrared transmission illumination 10. Besides, a 1st system for obtaining a 1st image and a 2nd image by alternatively lighting the L-shaped bar illumination 9 and the infrared transmission illuminating 10, and a 2nd system for obtaining the images by simultaneously lighting the L-shaped bar illumination 9 and the infrared transmission illumination 10 are introduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polarizing plate attachment position inspection apparatus that inspects whether or not a polarizing plate attached on a substrate facing a light shielding film covering the periphery of a pixel is attached at a normal position.

  Conventionally, in a liquid crystal display device or the like, a polarizing plate is pasted on a substrate so as to face a light shielding film called a black matrix covering the periphery of a pixel. FIG. 14A is a cross-sectional view showing a main part of a liquid crystal panel used in the liquid crystal display device. FIG. 14B is a plan view of FIG. 14A viewed from the A direction.

  In the figure, reference numeral 1 denotes an upper substrate, 2 denotes a lower substrate, 3 denotes a liquid crystal layer sandwiched between the substrates 1 and 2, and 4 denotes a seal layer for bonding the substrates 1 and 2 around. The liquid crystal layer 3 is sealed between the substrates 1 and 2 by a sealing layer 4. Substrates 1 and 2 are thin transparent glass plates. A common electrode (not shown) is formed on the upper substrate 1, and a pixel electrode (not shown) is formed for each pixel on the lower substrate 2. Has been. The common electrode and pixel electrode formed on the substrates 1 and 2 are transparent.

  A black matrix 5 is formed on the surface of the substrate 2 on the liquid crystal layer 3 side (the inner surface of the substrate 2). The black matrix 5 is a light-shielding film that covers the periphery of the pixels, and has a mesh-like pattern (hereinafter referred to as a BM pattern) 5-1 that transmits light to each pixel electrode formed on the substrate 2. doing. In the black matrix 5, a light shielding film is left in a frame shape around the BM pattern 5-1. Hereinafter, the region 5-2 where the light shielding film is left in the frame shape is referred to as a frame region.

  A polarizing plate 6 is attached to the outer surface (upper surface) of the substrate 1 so as to cover the BM pattern 5-1 of the black matrix 5 provided on the substrate 2 side. A polarizing plate 7 is attached to the outer surface of the substrate 2 so as to cover the BM pattern 5-1 of the black matrix 5. Reference numeral 8 denotes a lead electrode portion formed on the substrate 1.

[Inspection of polarizing plate attachment position]
In the manufacturing process of the liquid crystal display device, the polarizing plates 6 and 7 must be attached to normal positions on the substrates 1 and 2. For this reason, for example, in Patent Document 1, as shown in FIG. 14B, openings H1 are provided at the corners of the frame region 5-2 of the black matrix 5, and marks M1 are printed at the corners of the polarizing plate 6, The inspector visually confirms the overlapping state of the opening H1 and the mark M1.

  That is, the inspector determines that the polarizing plate 6 is attached to a normal position on the substrate 1 if all the openings H1 are hidden by the mark M1. On the other hand, if the opening H1 protrudes from the mark M1 (see FIG. 15), it is determined that the polarizing plate 6 is not attached to a normal position on the substrate 1. The mark M1 is printed on the polarizing plate 7 in the same manner as the polarizing plate 6, and the attachment position is inspected in the same manner as the polarizing plate 6.

Japanese Patent Laid-Open No. 10-282464

However, in the inspection method for the polarizing plate attachment position described in Patent Document 1 described above, since it is visually inspected by an inspector, efficiency is poor and a human inspection error may occur.
In addition, it is necessary to provide openings at the corners of the black matrix or to print marks at the corners of the polarizing plate, which increases the man-hours.

  The present invention has been made in order to solve such problems. The object of the present invention is to automate the inspection process of the attaching position of the polarizing plate to increase the efficiency of the inspection and to make an artificial inspection error. To provide a polarizing plate attachment position inspection device capable of automatically inspecting the attachment position of the polarizing plate without extra processing of the light shielding film and the polarizing plate. is there.

  In order to achieve such an object, the present invention provides a first illuminating means for illuminating at least one corner portion of a substrate on which a polarizing plate is attached, and a polarizing plate on the substrate. The second illuminating means for illuminating from the side opposite to the surface being illuminated, the imaging means for imaging the corner portion from the surface side where the polarizing plate of the substrate is affixed, and imaging by illumination by the first illuminating means Based on the position of the edge of the polarizing plate that appears in the image and the position of the pattern of the light shielding film that appears in the captured image due to illumination by the second illumination means, it is determined whether or not the polarizing plate is attached to the normal position Pass / fail judgment means is provided.

  According to this invention, the corner portion of the substrate on which the polarizing plate is attached is illuminated from the side (straight side) by the first illumination means, and the corner portion of the substrate on which the polarizing plate is attached is provided by the second illumination means, Illuminated from the side opposite to the side where the polarizing plate is attached (directly below), and the corner portion of the substrate where the polarizing plate is attached is imaged from the side where the polarizing plate is attached by the imaging means (directly above) Is done. Here, when the illumination light of the first illumination means is, for example, red light, and the illumination light of the second illumination means is, for example, infrared light, the captured image has an edge of the polarizing plate by illumination by the first illumination means. And a pattern of a light shielding film appears by illumination by the second illumination means.

  That is, when the corner portion is illuminated from the side by the first illuminating means, light is irregularly reflected at the edge surface of the polarizing plate attached on the substrate, and the edge of the polarizing plate appears in the captured image by the light. Further, when the corner portion is illuminated from directly below by the second illumination means, the illumination light is transmitted through the substrate and the polarizing plate, but is blocked by the light shielding film, and the light and darkness of the light appears in the captured image. Let For example, when the inspection target is a liquid crystal panel, a BM pattern appears as the pattern of the light shielding film.

  The pass / fail determination means determines whether or not the polarizing plate is attached to a normal position from the position of the edge of the polarizing plate appearing in the captured image and the position of the pattern of the light shielding film. For example, the coordinates (X1, Y1) of the edge of the polarizing plate appearing in the picked-up image are obtained, and the coordinates (X2, Y2) of the vertex of the pattern of the light shielding film appearing in the picked-up image are obtained. Whether or not the polarizing plate is attached to a normal position is determined based on the positional deviation between the coordinates (X1, Y1) of the light and the coordinates (X2, Y2) of the vertex of the light shielding film pattern.

In the present invention, the first illuminating means and the second illuminating means may be switched and lit or may be lit simultaneously.
When switching between the first illumination means and the second illumination means (method 1), the image captured by the imaging means when the first illumination means is lit is captured as the first image. The image taken by the imaging means when the second illumination means is turned on is taken as the second image, and the position of the edge of the polarizing plate appearing in the first image and the position of the pattern of the light shielding film appearing in the second image Based on the above, it is determined whether or not the polarizing plate is attached to a normal position.
When the first illumination means and the second illumination means are turned on simultaneously (method 2), the image is taken by the imaging means when the first illumination means and the second illumination means are turned on simultaneously. An image is captured, and it is determined whether or not the polarizing plate is attached to a normal position based on the position of the edge of the polarizing plate appearing in this image and the position of the pattern of the light shielding film.

  In the method 2 in which the first illumination unit and the second illumination unit are turned on simultaneously, an algorithm capable of simultaneously recognizing and measuring the edge position of the polarizing plate and the pattern position of the light shielding film is required. It is necessary to assemble a more complicated algorithm than the method 1 that switches between the second illumination means and the second illumination means. However, if method 2 is used, the pass / fail judgment speed is faster than method 1. In addition, since the position of the edge of the polarizing plate and the pattern of the light shielding film can be obtained from one captured image, the accuracy of quality determination is improved. As described above, method 1 has an advantage that a simple algorithm may be used, and method 2 has an advantage that the accuracy of pass / fail judgment is increased at the same time, and the pass / fail judgment accuracy is improved. It is good to use properly.

In the present invention, the illumination light of the first illumination means is not limited to red light. Further, the illumination light of the second illumination means is not limited to infrared light as long as it is light that passes through the substrate and the polarizing plate but does not pass through the light shielding film.
In addition, when the first illumination unit and the second illumination unit are switched on and turned on, a member that absorbs illumination light from the first illumination unit is provided on the light emitting surface of the second illumination unit. Thus, it is possible to eliminate the possibility that the light shielding pattern is reflected in the first image.

  According to the present invention, from the position of the edge of the polarizing plate appearing in the captured image and the position of the pattern of the light shielding film, it is automatically determined whether or not the polarizing plate is attached to a normal position. It is possible to automate the inspection process for the position where the polarizing plate is attached to increase the efficiency of inspection and to eliminate human inspection errors. Further, the attaching position of the polarizing plate can be automatically inspected without extra processing such as printing an opening or a mark on the light shielding film or the polarizing plate.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a main part of an embodiment of a polarizing plate attachment position inspection apparatus according to the present invention.
The polarizing plate pasting position inspection device 200 includes an L-shaped bar illumination 9, an infrared transmission illumination 10, an imaging device (camera) 11, a main control unit 12, an image processing unit 13, and an illumination control unit. 14 and an illumination power source 15.

  FIG. 1 shows a state in which the liquid crystal panel 100 to be inspected is set in the polarizing plate pasting position inspection apparatus 200, and the structure of the liquid crystal panel 100 is the same as that shown in FIG. However, in the liquid crystal panel 100, the mark M <b> 1 is not printed on the polarizing plates 6 and 7, and the opening H <b> 1 is not provided in the black matrix 5. The liquid crystal layer 3 is normally white that allows light to pass therethrough without applying an electric field. FIG. 2 shows a configuration diagram of the apparatus when the liquid crystal panel 100 in FIG. 1 is viewed from the lateral direction.

  In a state where the liquid crystal panel 100 is set, the L-shaped bar illumination 9 is located on the side of a corner portion (in this example, the lower left corner of the liquid crystal panel 100) C1 of the liquid crystal panel 100. 100 corner portions C1 are illuminated with red light from the side. That is, the corner portion C1 is irradiated with red light directly from both the front side and the left side. This L-shaped bar illumination 9 corresponds to the first illumination means in the present invention. The L-shaped bar illumination 9 has, for example, a configuration in which red LEDs are arranged in a horizontal direction, and is opposed to the first bar illumination 9-1 facing the front side of the corner portion C1 and the left side of the corner portion C1. It comprises a second bar illumination 9-2.

  In a state where the liquid crystal panel 100 is set, the infrared transmissive illumination 10 is positioned below the corner portion C1 of the liquid crystal panel 100, and the corner portion C1 is illuminated with infrared light from directly below. That is, as shown in FIG. 1, when the liquid crystal panel 100 is set with the polarizing plate 6 as the upper side, infrared light is applied to the corner portion C <b> 1 from the lower surface side of the substrate 1. This infrared transmission illumination 10 corresponds to the second illumination means in the present invention. Infrared light from the infrared transmission illumination 10 is transmitted through the substrates 1 and 2, the liquid crystal layer 3, and the polarizing plates 6 and 7, but not transmitted through the black matrix (light-shielding film) 5 due to the properties of the light.

  In a state where the liquid crystal panel 100 is set, the camera 11 is positioned above the corner portion C1 of the liquid crystal panel 100, and images the corner portion C1 from directly above. That is, as shown in FIG. 1, when the liquid crystal panel 100 is set with the polarizing plate 6 on the upper side, the corner portion C <b> 1 is imaged from the upper surface side of the substrate 1.

  The main control unit 12 sends a command to the illumination control unit 14 to control turning on / off of the L-shaped bar illumination 9 and the infrared transmission illumination 10. The illumination control unit 14 controls the illumination power supply 15 according to a command from the main control unit 12, and controls on / off of the power supply to the L-shaped bar illumination 9 and the infrared transmission illumination 10.

  Further, the main control unit 12 sends a command to the image processing unit 13 to control the imaging timing of the camera 11. The image processing unit 13 captures and processes an image captured by the camera 11 and sends the processed image to the main control unit 12. The main control unit 12 obtains the position information of the black matrix and the polarizing plate from the processed image sent from the image processing unit 13, and determines whether or not the polarizing plate is pasted at a normal position.

  In the present embodiment, the main control unit 12, the image processing unit 13, and the illumination control unit 14 are hardware including a processor and a storage device, and a program that realizes various functions in cooperation with these hardware. It is realized by.

[Embodiment 1: Method 1 (alternate illumination)]
FIG. 3 shows an example (first embodiment) of a flowchart of the polarizing plate pasting position inspection process executed by the main controller 12. In the first embodiment, the main control unit 12 switches the L-shaped bar illumination 9 and the infrared transmission illumination 10 alternately to light up, and the camera is turned on when the L-shaped bar lighting 9 is on. 11 is attached to the normal position based on the image captured by the camera 11 (first image) and the image captured by the camera 11 when the infrared transmission illumination 10 is lit (second image). It is judged whether or not it is good. The specific processing operation will be described below according to this flowchart.

  The main control unit 12 sends a lighting command for the L-shaped bar illumination (first illumination) 9 to the illumination control unit 14 (step 301). Upon receiving this command, the illumination control unit 14 starts supplying power from the illumination power supply 15 to the L-shaped bar illumination 9. As a result, the L-shaped bar illumination 9 is turned on, and the corner portion C1 of the liquid crystal panel 100 set as the inspection target is illuminated with red light from the side.

  Further, the main control unit 12 sends a command to the image processing unit 13 and causes the camera 11 to capture an image of the corner portion C1 when the L-shaped bar illumination 9 is lit (step 302). The image of the corner portion C1 picked up by the camera 11 is taken into the image processing portion 13 as a first image.

  FIG. 4A illustrates a first image captured by the camera 11. When the corner C1 of the liquid crystal panel 100 is illuminated from the side with red light by the L-shaped bar illumination 9, light is irregularly reflected on the edge surface of the polarizing plate 6 stuck on the substrate 1, and the light is reflected in the captured image. The edge of the polarizing plate 6 appears. In addition, light is irregularly reflected on the edge surface of the substrate 1, and the edge of the substrate 1 also appears in the captured image. In FIG. 4A, a white line L <b> 1 that is white is the edge of the polarizing plate 6. The edge of the substrate 1 also appears as a line L2 outside the line L1.

  By illuminating the corner portion C1 from the side with the L-shaped bar illumination 9, scratches, dirt, circuit patterns, etc. on the surface of the polarizing plate 6 and the substrate 1 become difficult to be visualized. Edges can stand out.

  FIG. 6 is an image example when ring-shaped illumination is provided above the corner portion C1. In the ring-type illumination, the corner portion C1 is illuminated from all directions, so that even the surface of the polarizing plate 6 and the substrate 1, such as scratches, dirt, and circuit patterns, are visualized and distinguished from the edge of the polarizing plate 6. There is a risk that it will not stick. On the other hand, when the L-shaped bar illumination 9 is used, the illumination direction is two directions, that is, the front side and the left side, and scratches, dirt, circuit patterns, etc. on the surface of the polarizing plate 6 and the substrate 1 are visualized. It becomes difficult to be done.

  Next, the main control unit 12 sends a lighting command for the infrared transmission illumination (second illumination) 10 to the illumination control unit 14 (step 303). Upon receiving this instruction, the illumination control unit 14 interrupts the supply of power from the illumination power supply 15 to the L-shaped bar illumination 9 and starts supplying power to the infrared transmission illumination 10. Thereby, the L-shaped bar illumination 9 is turned off, the infrared transmission illumination 10 is turned on, and the corner portion C1 of the liquid crystal panel 100 is illuminated with infrared light from directly below.

  Further, the main control unit 12 sends a command to the image processing unit 13 to cause the camera 11 to take an image of the corner portion C1 when the infrared transmission illumination 10 is turned on (step 304). The image of the corner portion C1 picked up by the camera 11 is taken into the image processing portion 13 as a second image.

  FIG. 5A illustrates a second image captured by the camera 11. When the corner C1 of the liquid crystal panel 100 is illuminated with infrared light from directly below by the infrared transmission illumination 10, the illumination light is transmitted through the substrates 1, 2, the liquid crystal layer 3, and the polarizing plates 6 and 7, while the black matrix (light shielding) The light and darkness of the light is blocked by the (film) 5, and the BM pattern 5-1 of the black matrix 5 appears in the captured image. In FIG. 5A, the BM pattern 5-1 of the black matrix 5 appears as a mesh-like shadow S1. S2 is a shadow indicating the frame region 5-2 of the black matrix 5, and S3 is a shadow indicating the lead electrode portion 8 formed on the substrate 1.

  The image processing unit 13 captures the first image captured in step 302, captures the second image captured in step 304, performs noise removal processing, and the like, and performs the processed first and second images. Is sent to the main control unit 12.

  From the first image sent from the image processing unit 13, the main control unit 12 uses a horizontal line (horizontal line) L1a (see FIG. 4B) of the line L1 indicating the edge of the polarizing plate 6 and a vertical line ( The vertical line L1b is extracted by scanning in the vertical and horizontal directions, and the coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 are obtained as the intersection of the extracted vertical and horizontal lines (step 305). Further, the inclination of the horizontal line L1a extracted when obtaining the coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 and the inclination of the vertical line L1b with respect to the Y axis are obtained (step 306).

  Further, the main control unit 12 determines, from the second image sent from the image processing unit 13, a boundary line between the shadow S1 indicating the BM pattern 5-1 of the black matrix 5 and the shadow S2 indicating the frame region 5-2 ( The contour line of the BM pattern) L3 (see FIG. 5B), the horizontal line (horizontal line) L3a and the vertical line (vertical line) L3b are extracted by scanning in the vertical and horizontal directions. As an intersection, the coordinates (X2, Y2) of the vertex T2 of the BM pattern 5-1 are obtained (step 307). Further, the inclination of the horizontal line L3a extracted when obtaining the coordinates (X2, Y2) of the vertex T2 of the BM pattern 5-1 and the inclination of the vertical line L3b with respect to the Y axis are obtained (step 308).

  The main control unit 12 then displays the horizontal line L1a and vertical line L1b of the line L1 indicating the edge of the polarizing plate 6 obtained in step 306 and the horizontal line L3a and vertical line of the contour line L3 obtained in step 308. The relative inclination with L3b is checked, and it is confirmed whether or not the relative inclination is within an allowable range (step 309). Here, if the relative inclination of the vertical and horizontal lines is not within the allowable range (NO in step 309), it is determined that the polarizing plate 6 is not attached to a normal position, and the determination result is sent to the host device. .

  If the relative inclination of the vertical and horizontal lines is within the allowable range (YES in step 309), the main control unit 12 obtains the coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 obtained in step 305 and in step 307. A difference from the coordinates (X2, Y2) of the vertex T2 of the BM pattern 5-1 is obtained, and it is confirmed whether or not the difference is within an allowable range (step 310). That is, the difference (X1-X2) in the X coordinate is obtained, and it is confirmed whether or not the difference is within a predetermined allowable range α. Further, a difference between Y coordinates (Y1−Y2) is obtained, and it is confirmed whether or not the difference is within a predetermined allowable range β.

  If the X coordinate difference (X1−X2) is within the allowable range α and the Y coordinate difference (Y1−Y2) is within the allowable range β, the polarizing plate 6 is attached to a normal position. (YES in step 310), the determination result is sent to the host device, and the process returns to step 301 to repeat the same operation for the next inspection object. On the other hand, if either the X coordinate difference (X1-X2) or the Y coordinate difference (Y1-Y2) is not within the allowable range, the main control unit 12 attaches the polarizing plate 6 to a normal position. It is determined that it is not attached (NO in step 310), and the determination result is sent to the host device.

  FIG. 7 is a diagram illustrating a second image when a red LED transmissive illumination is used instead of the infrared transmissive illumination 10. That is, it is a diagram illustrating a second image when red light is irradiated instead of infrared light from directly below the corner portion C1 of the liquid crystal panel 100. FIG. If the transmittance of the polarizing plates 6 and 7 is high, a second image in which the shadow S1 of the BM pattern 5-1 appears as shown in FIG. . However, if the transmittance of the polarizing plates 6 and 7 is low, the red light from the red LED transmission illumination is blocked by the polarizing plates 6 and 7, and the second image has a BM pattern 5-1 as shown in FIG. Shadow S1 no longer appears. On the other hand, since infrared light is transmitted through the polarizing plates 6 and 7 even if the transmittance is low, the BM pattern 5 is displayed on the second image without being affected by the transmittance of the polarizing plates 6 and 7. -1 shadow S1 can appear.

  In the case of the configuration shown in FIG. 1, when the infrared transmission illumination 10 is turned off and the L-shaped bar illumination 9 is lit, the light from the L-shaped bar illumination 9 is shown in FIG. May be reflected by the light emitting surface of the infrared transmissive illumination 10, and the shadow S1 of the BM pattern 5-1 may appear in the first image (see FIG. 9). When the shadow S1 of the BM pattern 5-1 appears in the first image, the line L1 indicating the edge of the polarizing plate 6 cannot be well extracted by scanning the first image in the vertical and horizontal directions.

  For example, as shown in FIG. 10, the problem is that a member that transmits infrared light from the infrared transmission illumination 10 but absorbs light from the L-shaped bar illumination 9 to the light emitting surface of the infrared transmission illumination 10. This can be solved by providing the (reflected light noise filter) 16. That is, by providing the reflected light noise filter 16, light from the L-shaped bar illumination 9 is not reflected toward the corner portion C1 of the liquid crystal panel 100, and the shadow S1 of the BM pattern 5-1 is added to the first image. It will not appear (see FIG. 11). In the example of FIG. 10, the reflected light noise filter 16 is provided on the light emitting surface of the infrared transmissive illumination 10, but a light shielding plate is provided between the L-shaped bar illumination 9 and the light emitting surface of the infrared transmissive illumination 10. It may be provided.

[Embodiment 2: Method 2 (simultaneous illumination)]
FIG. 12 shows another example (Embodiment 2) of the flowchart of the polarizing plate attachment position inspection process executed by the main control unit 12. In the second embodiment, the main control unit 12 turns on the L-shaped bar illumination 9 and the infrared transmission illumination 10 at the same time, and turns on the L-shaped bar illumination 9 and the infrared transmission illumination 10 at the same time. Whether or not the polarizing plate is attached to a normal position is determined based on the image captured by the camera 11. The specific processing operation will be described below according to this flowchart.

  The main control unit 12 sends to the illumination control unit 14 a simultaneous lighting command for the L-shaped bar illumination (first illumination) 9 and the infrared transmission illumination (second illumination) 10 (step 121). Upon receiving this command, the illumination control unit 14 starts supplying power from the illumination power supply 15 to the L-shaped bar illumination 9 and the infrared transmission illumination 10. Thereby, the L-shaped bar illumination 9 is turned on, and the corner portion C1 of the liquid crystal panel 100 is illuminated from the side with red light. Further, the infrared transmission illumination 10 is turned on, and the corner portion C1 of the liquid crystal panel 100 is illuminated with infrared light from directly below.

  Further, the main control unit 12 sends a command to the image processing unit 13, and causes the camera 11 to capture an image of the corner portion C1 when the L-shaped bar illumination 9 and the infrared transmission illumination 10 are lit simultaneously (step S1). 122). An image of the corner portion C <b> 1 captured by the camera 11 is captured by the image processing unit 13.

  FIG. 13A illustrates an image captured by the camera 11. When the corner C1 of the liquid crystal panel 100 is illuminated with infrared light from directly below by the infrared transmission illumination 10, the illumination light is transmitted through the substrates 1, 2, the liquid crystal layer 3, and the polarizing plates 6 and 7, while the black matrix (light shielding) The light and darkness of the light is blocked by the (film) 5, and the BM pattern 5-1 of the black matrix 5 appears in the captured image. In FIG. 13A, the BM pattern 5-1 of the black matrix 5 appears as a mesh-like shadow S1. S2 is a shadow indicating the frame region 5-2 of the black matrix 5, and S3 is a shadow indicating the lead electrode portion 8 formed on the substrate 1.

  When the corner portion C1 of the liquid crystal panel 100 is illuminated with red light from the side by the L-shaped bar illumination 9, the light is irregularly reflected on the edge surface of the polarizing plate 6 stuck on the substrate 1, and the light is reflected in the captured image. The edge of the polarizing plate 6 appears. In FIG. 13A, a white line L <b> 1 that floats white is the edge of the polarizing plate 6, and floats white by contrast with the shadow S <b> 2 indicating the frame region 5-2 of the black matrix 5. In this case, although light is irregularly reflected also at the edge surface of the substrate 1, the edge of the substrate 1 does not appear in the captured image because the infrared light from the infrared transmission illumination 10 is applied from directly below.

  The image processing unit 13 captures the image captured in step 122, performs noise removal processing, and the like, and sends the processed image to the main control unit 12.

  Based on the image sent from the image processing unit 13, the main control unit 12 determines the boundary line between the shadow S1 indicating the BM pattern 5-1 of the black matrix 5 and the shadow S2 indicating the frame region 5-2 (the contour of the BM pattern). Line) L3 (see FIG. 13B), a horizontal line (horizontal line) L3a and a vertical line (vertical line) L3b are extracted by scanning in the vertical and horizontal directions, and a BM pattern is used as an intersection of the extracted vertical and horizontal lines. The coordinates (X2, Y2) of the vertex T2 of 5-1 are obtained (step 123). Further, the inclination of the horizontal line L3a extracted when obtaining the coordinates (X2, Y2) of the vertex T2 of the BM pattern 5-1 and the inclination of the vertical line L3b with respect to the Y axis are obtained (step 124).

  The main controller 12 scans the horizontal line (horizontal line) L1a and the vertical line (vertical line) L1b of the line L1 (see FIG. 13B) indicating the edge of the polarizing plate 6 in the vertical and horizontal directions. The coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 are obtained as intersections of the extracted vertical and horizontal lines (step 125). Further, the inclination of the horizontal line L1a extracted when obtaining the coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 and the inclination of the vertical line L1b with respect to the Y axis are obtained (step 126). The horizontal line L1a and the vertical line L1b of the line L1 indicating the edge of the polarizing plate 6 can be extracted as lines found after exceeding the horizontal line L3a and the vertical line L3b of the boundary line L3 of the BM pattern.

  Then, the main control unit 12 compares the horizontal line L3a and vertical line L3b of the contour line L3 of the BM pattern obtained in step 124 and the horizontal line L1a and vertical line L1b of the line L1 indicating the edge of the polarizing plate 6 obtained in step 126. The relative inclination is checked, and it is confirmed whether or not the relative inclination is within an allowable range (step 127). Here, if the relative inclination of the vertical and horizontal lines is not within the allowable range (NO in step 127), it is determined that the polarizing plate 6 is not attached to a normal position, and the determination result is sent to the host device. .

  If the relative inclination of the vertical and horizontal lines is within the allowable range (YES in step 127), the main control unit 12 obtains the coordinates (X1, Y1) of the vertex T1 of the polarizing plate 6 obtained in step 125 and in step 123. The difference from the coordinates (X2, Y2) of the vertex T2 of the BM pattern 5-1 is obtained, and it is confirmed whether or not the difference is within the allowable range in the same manner as in step 310 shown in FIG. 3 (step 128). ).

  Here, the main control unit 12 determines that the polarizing plate 6 is normal if the X coordinate difference (X1−X2) is within the allowable range α and the Y coordinate difference (Y1−Y2) is within the allowable range β. It is determined that the position is pasted (YES in step 128), and the determination result is sent to the host device, and the process returns to step 121 to repeat the same operation for the next inspection target. On the other hand, if either one of the X coordinate difference (X1-X2) and the Y coordinate difference (Y1-Y2) is not within the allowable range, it is determined that the polarizing plate 6 is not attached to a normal position. (NO in step 128), and the determination result is sent to the host device.

  In the second embodiment, an algorithm capable of simultaneously recognizing and measuring the line L1 indicating the edge of the polarizing plate 6 and the line L3 indicating the outline of the BM pattern 5-1 is required, and a more complicated algorithm than that in the first embodiment is required. It is necessary to assemble. However, the pass / fail judgment speed is faster than in the first embodiment. Moreover, since the line L1 which shows the edge of the polarizing plate 6 and the line L3 which shows the outline of the BM pattern 5-1 are obtained from one picked-up image, the determination accuracy of quality is improved. That is, in the first embodiment, since the imaging timing of the first image and the imaging timing of the second image are different, the difference in the captured environment may affect the accuracy of the quality determination. On the other hand, in Embodiment 2, there is no difference in the imaged environment, and the accuracy of the pass / fail determination is improved.

  As described above, the first embodiment (method 1) has an advantage that a simple algorithm may be used, and the second embodiment (method 2) has an advantage that the pass / fail judgment speed is increased and the pass / fail judgment accuracy is improved. Yes, which method should be used may be used depending on the case. In the second embodiment, since the L-shaped bar illumination 9 and the infrared transmissive illumination 10 are turned on simultaneously, the light from the L-shaped bar illumination 9 is reflected by the light emitting surface of the infrared transmissive illumination 10. There is no problem, and it is not necessary to provide the reflected light noise filter 16 as shown in FIG.

  In the first and second embodiments described above, the case where it is inspected whether or not the polarizing plate 6 attached to the upper substrate 1 is attached to a normal position has been described as an example. It is also possible to inspect whether or not the polarizing plate 7 attached to 2 is attached at a normal position. In this case, the liquid crystal panel 100 may be turned upside down and set with the polarizing plate 7 on the upper side, and on the substrate 2 facing the black matrix 5 by exactly the same processing operation as described in the first and second embodiments. It can be inspected whether or not the polarizing plate 7 attached to is attached to a normal position.

  In Embodiments 1 and 2 described above, only one set of L-shaped bar illumination 9 and infrared transmission illumination 10 is provided, but a plurality of sets may be provided. That is, not only the lower left corner of the liquid crystal panel 100 to be inspected but also another corner portion such as the upper right corner is provided with the L-shaped bar illumination 9 and the infrared transmission illumination 10, and at a plurality of locations. You may make it test | inspect whether the polarizing plate 6 is affixed on the normal position based on the result. Further, the L-shaped bar illumination 9 may be integrated, or the bar illumination 9-1 and the bar illumination 9-2 may be slidably separated so that their positions can be adjusted.

In the first and second embodiments described above, the first illumination is red light, but is not limited to red light. In addition, although the second illumination is infrared light, it is sufficient that the light is transmitted through the substrates 1 and 2 and the polarizing plates 6 and 7 but not transmitted through the black matrix (light-shielding film) 5. Also good. At present, infrared light is the most promising light that passes through the polarizing plates 6 and 7 even if the transmittance is low.
In the first and second embodiments described above, the liquid crystal panel is taken as an example of the inspection target. However, any panel can be used as long as the polarizing plate is pasted on the substrate facing the light shielding film. It is good also as inspection object.

  As described above, according to the present embodiment, the inspection process of the attaching position of the polarizing plates 6 and 7 is automated, the inspection efficiency is increased, and human inspection errors are eliminated. In addition, the attaching position of the polarizing plates 6 and 7 can be automatically inspected without extra processing such as printing openings and marks on the black matrix 5 and the polarizing plates 6 and 7.

It is a block diagram which shows the principal part of one Embodiment of the polarizing plate sticking position inspection apparatus which concerns on this invention. It is the block diagram of the apparatus which looked at the liquid crystal panel in FIG. 1 from the horizontal direction. It is a flowchart which shows an example (Embodiment 1) of the polarizing plate sticking position inspection process which the main control part performs in this polarizing plate sticking position inspection apparatus. It is a figure which shows the coordinate (X1, Y1) of the vertex of the polarizing plate calculated | required from the 1st image imaged with the camera, and this 1st image. It is a figure which shows the coordinate (X2, Y2) of the vertex of the BM pattern calculated | required from the 2nd image imaged with the camera, and this 2nd image. It is the photograph on a display which shows an image at the time of providing ring type illumination above the corner part of a liquid crystal panel. It is a figure which illustrates the 2nd picture at the time of using red LED transmission illumination instead of infrared transmission illumination. It is a figure which shows the condition where the light from L-shaped bar illumination reflects on the light emission surface of infrared transmission illumination. It is a figure which illustrates the 1st image at the time of the light from L-shaped bar illumination reflecting on the light emission surface of infrared transmission illumination. It is a figure which shows the example which provided the reflected light noise filter in the light emission surface of infrared transmission illumination, and prevented reflection of the light from L-shaped bar illumination. It is a figure which illustrates the 1st image obtained when a reflected light noise filter is provided in the light emission surface of infrared transmission illumination. It is a flowchart which shows the other example (Embodiment 2) of the polarizing plate sticking position inspection process which a main control part performs. It is a figure which shows the coordinate (X1, Y1) of the vertex of the polarizing plate calculated | required from the image imaged with the camera, and this image, and the coordinate (X2, Y2) of the vertex of BM pattern. It is sectional drawing and a top view which show the principal part of the liquid crystal panel used for a liquid crystal display device. It is a figure which shows the state which the opening H1 protruded from the mark M1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate (upper substrate), 2 ... Substrate (lower substrate), 3 ... Liquid crystal layer, 4 ... Seal layer, 5 ... Black matrix, 5-1 ... BM pattern, 5-2 ... Frame region, 6 ... Polarizing plate (upper polarizing plate), 7 ... polarizing plate (lower polarizing plate), 8 ... lead electrode portion, C1 ... corner portion, 100 ... liquid crystal panel, 9 ... L-shaped bar illumination, 9-1, 9-2 ... Bar illumination, 10 ... Infrared transmission illumination, 11 ... Imaging device (camera), 12 ... Main control unit, 13 ... Image processing unit, 14 ... Illumination control unit, 15 ... Power supply for illumination, 16 ... Reflected light Noise filter, 200: polarizing plate attachment position inspection device, T1: vertex of polarizing plate, T2: vertex of BM pattern, L1: line indicating edge of polarizing plate, L2: line indicating edge of substrate, L3: BM pattern A line indicating the outline of S1, a mesh-like shadow indicating a BM pattern, S2, a frame Shadow indicating the frequency, S3 shadow showing a lead electrode portion.

Claims (3)

A polarizing plate attachment position inspection device that inspects whether or not the polarizing plate attached on the substrate facing the light shielding film covering the periphery of the pixel is attached to a normal position,
A first illuminating means for illuminating at least one corner portion of the substrate on which the polarizing plate is attached from the side;
A second illuminating means for illuminating the corner portion from the surface opposite to the surface on which the polarizing plate of the substrate is attached;
Imaging means for imaging the corner portion from the surface side where the polarizing plate of the substrate is attached,
The position of the edge of the polarizing plate that appears in the captured image of the imaging means by illumination by the first illumination means, and the position of the pattern of the light shielding film that appears in the captured image of the imaging means by illumination by the second illumination means And a pass / fail judgment means for judging whether or not the polarizing plate is pasted at a normal position. A polarizing plate attachment position inspection device that inspects whether or not the polarizing plate attached on the substrate facing the light shielding film covering the periphery of the pixel is attached to a normal position,
A first illuminating means for illuminating at least one corner portion of the substrate on which the polarizing plate is attached from the side;
A second illuminating means for illuminating the corner portion from the surface opposite to the surface on which the polarizing plate of the substrate is attached;
Imaging means for imaging the corner portion from the surface side where the polarizing plate of the substrate is attached,
Illumination control means for switching on and lighting the first illumination means and the second illumination means;
An image captured by the imaging unit when the first illumination unit is turned on is captured as a first image, and an image captured by the imaging unit when the second illumination unit is turned on. Based on the position of the edge of the polarizing plate that appears in the first image and the position of the pattern of the light shielding film that appears in the second image, the polarizing plate is attached to a normal position. A polarizing plate pasting position inspection device comprising: a quality determining unit that determines whether or not there is a polarizing plate. A polarizing plate attachment position inspection device that inspects whether or not the polarizing plate attached on the substrate facing the light shielding film covering the periphery of the pixel is attached to a normal position,
A first illuminating means for illuminating at least one corner portion of the substrate on which the polarizing plate is attached from the side;
A second illuminating means for illuminating the corner portion from the surface opposite to the surface on which the polarizing plate of the substrate is attached;
Imaging means for imaging the corner portion from the surface side where the polarizing plate of the substrate is attached,
Illumination control means for simultaneously lighting the first illumination means and the second illumination means;
The image taken by the imaging means is captured when the first illumination means and the second illumination means are turned on at the same time, and the position of the edge of the polarizing plate appearing in this image and the pattern of the light shielding film And a pass / fail judgment means for judging whether or not the polarizing plate is stuck at a normal position based on the position of the polarizing plate.

Images