JP2010230338A - Device for inspecting lighting of liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems in a device for inspecting lighting of a liquid crystal panel having surface illumination, a back polarizing plate, a panel to be inspected, a surface polarizing plate, a surface polarizing plate holding implement and an image pick-up part including a plurality of area sensors and fixing implements for the area sensors, wherein when a large-sized surface polarizing plate capable of covering the area sensors in a plurality is installed on the surface polarizing plate holding implement, the frequency of work for cleaning at sticking of stains or the work for replacement on the occasion of damage is increased, since the area of the surface polarizing plate is large, and moreover the work for alignment for making the polarization axes of the back polarizing plate and the surface polarizing plate intersect each other at right angles becomes necessary in the replacement work, which results in the increase in the working cost, at replacement. <P>SOLUTION: The device for inspecting lighting of the liquid crystal panel consists of the two or more area sensors, an area sensor frame, a strip-shaped surface polarizing plate, the back polarizing plate, a backlight and an inspection processing part, and the light transmitted through the single strip-shaped surface polarizing plate enters the area sensors in a plurality. The area sensor frame has a polarizing-plate installing implement for installing the strip-shaped surface polarizing plate, and this implement has a positioning implement which is brought into contact with the strip-shaped surface polarizing plate on the long side of the plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lighting inspection device for a liquid crystal panel used in a display device such as a display.

  Flat panel displays (FPD) such as liquid crystal panels are visually inspected for minute point defects, foreign object defects, spots, unevenness, etc. in the display surface in order to ensure quality. However, the size of FPDs has increased, and it takes a lot of time to visually detect minute point defects and foreign matter defects existing on a large screen, and furthermore, the fine defects are overlooked due to fatigue of the visual inspector. The problem has occurred.

  In order to solve such problems, in the inspection of liquid crystal panels, a front polarizing plate and a rear polarizing plate are installed before and after the panel to be inspected so that the polarization axis direction is orthogonal or parallel. In some cases, a drive signal is given to a panel to be inspected to turn it on, an area sensor is used to image a display screen of the panel to be inspected, and inspection is automated by image processing (Patent Document 1). In addition, regarding the installation method of the polarizing plate for inspection before and after the panel to be inspected before attaching the polarizing plate, in order to improve the orthogonality or parallel accuracy of the polarization axis direction of the front polarizing plate and the back polarizing plate, There exists what provided the rotation mechanism (patent document 2). In recent years, liquid crystal panels have increased in size and definition, and a single camera can no longer cover the entire panel to be inspected. Therefore, a plurality of area sensors such as 9 to 16 can be arranged side by side. There are devices that inspect the entire surface of the inspection panel at once and at high speed. As described above, in order to compensate for the lack of resolution of the area sensor, a method of imaging a plurality of area sensors arranged side by side has been practiced for a long time in other fields. For example, there is an example used for inspection of an IC pattern wafer ( Patent Document 3).

Japanese Patent Laid-Open No. 3-61993 JP-A-6-242410 JP 2001-194322 A

  Considering the size and resolution of a liquid crystal panel for TV of recent years, imaging the entire surface of the panel to be inspected with one area sensor leads to a decrease in inspection performance due to insufficient resolution, which is difficult to realize. On the other hand, one area sensor is mounted on the XY stage, the panel to be inspected is divided into a plurality of sections, one section of the panel to be inspected is imaged by one area sensor, and the XY stage is sequentially moved while being moved. By repeating imaging in each section of the inspection panel, the entire surface of the panel to be inspected can be inspected. However, since the XY stage is moved sequentially, a lot of moving time for imaging is required, and as a result, the inspection time becomes long, which is not suitable for mass production. For these reasons, in order to perform inspection at high speed and with high accuracy, a method of arranging a plurality of area sensors and imaging the entire surface of the panel to be inspected at once is essential.

  When the method described in Patent Document 1 is applied to a structure in which a plurality of area sensors are arranged, a polarizing plate having the same size as the panel to be inspected is required. For example, the panel size for a 65-inch TV is 1440 mm in the vertical direction and horizontal. Therefore, the size of the polarizing plate is also 1440 × 810 mm. By the way, in order to maintain the inspection performance, cleaning is performed when the polarizing plate is dirty, replacement is performed when the polarizing plate is scratched, and the polarizing plate is deteriorated with time by ultraviolet rays emitted from the illumination for inspection. Therefore, it is necessary to periodically change the polarizing plate. The frequency and cost of the cleaning work increase with the area of the polarizing plate. Also, the work cost and the polarizing plate price at the time of replacement increase according to the area of the polarizing plate. That is, in the method described in Patent Document 1, an increase in the cleaning cost and replacement cost of the polarizing plate becomes a problem.

  If the method described in Patent Document 2 is applied to a structure in which a plurality of area sensors are arranged, a polarizing plate is installed in front of each area sensor. Cost increases. Furthermore, by providing each area sensor with a surface polarizing plate rotation mechanism for improving the orthogonality or parallel accuracy of the polarization axis directions of the front surface polarizing plate and the back surface polarizing plate, the apparatus cost increases.

  In order to solve the above problems, the present invention is composed of two or more area sensors, an area sensor mount, a strip-shaped surface polarizing plate, a back polarizing plate, a backlight, and an inspection processing unit. A liquid crystal panel lighting inspection apparatus in which light transmitted through a strip-shaped surface polarizing plate enters, wherein the area sensor mount includes a polarizing plate setting jig for setting the strip-shaped surface polarizing plate, and the polarizing plate setting The jig has a positioning jig that abuts on the long side of the strip-shaped surface polarizing plate.

  Further, the arrangement direction of the plurality of area sensors is one direction, and the arrangement direction and the arrangement direction of the polarizing plate installation jig coincide with each other.

  With this configuration, the strip-shaped surface polarizing plate that spans two or more cameras is positioned on the long side, and the strip-shaped surface polarizing plate is used as a camera by a lighting inspection apparatus using a large number of cameras. In this case, it is only necessary to install a smaller number of strip-shaped surface polarizing plates than the number of cameras, and the crossing angle between the polarization axis direction of the strip-shaped surface polarizing plate and the polarization axis direction of the back polarizing plate It becomes possible to easily achieve a predetermined state, and it is possible to reduce both the replacement work cost and the apparatus cost.

It is the figure which looked at the apparatus structure from the side. It is the figure which looked at the camera mount from the front. It is the figure which looked at the line composition which installs this inspection device from the front. In the line which installs this test | inspection apparatus, it is the figure which showed what kind of area | region the panel to be inspected is divided and imaged. It is the figure which outlined the structure of the imaging part. It is the figure which looked at the polarizing plate installation jig from the front. It is the figure which looked at the polarizing plate installation jig from the side. It is the figure which looked at the polarizing plate installation jig of the state which installed the polarizing plate from the front. It is the figure which looked at the camera stand of the state which installed the polarizing plate from the front. It is the figure which looked at the polarizing plate installation jig at the time of installing a polarizing plate for every camera from the front. It is the figure which looked at the camera stand at the time of installing a polarizing plate for every camera from the front. It is the figure which looked at the camera stand at the time of installing a polarizing plate vertically. It is the figure which looked at the polarizing plate installation jig of another form from the front.

An embodiment of the present invention will be described below with reference to FIGS. In addition, this invention is not limited to the lighting test | inspection apparatus of one Embodiment, It is possible to apply to all apparatuses.
(Configuration of lighting inspection device)
FIG. 1 is a schematic diagram illustrating a configuration of a lighting inspection apparatus according to an embodiment. The lighting inspection apparatus includes an inspection unit, an illumination unit, and an inspection processing unit (not shown). The inspection unit is connected to the area sensor gantry 3 via the area sensor attitude adjustment jig 2, and a total of nine area sensors 1 arranged in three rows and three columns, and polarizing plates in the shooting direction of each area sensor 1. A total of nine polarizing plate installation jigs are installed, and each polarizing plate installation jig includes a light shielding cover 4, a surface polarizing plate pressing jig 5, and a surface polarizing plate alignment pin 13. The strip-shaped surface polarizing plate 6 is installed between the light shielding cover 4 and the surface polarizing plate pressing jig 5 so as to cover the three area sensors 1 in the depth direction of FIG. Positioned by the plate alignment pin 13. The illumination unit includes a panel transport device 10, a backlight 9, and a back polarizing plate 8, and the panel transport device 10 carries in / out the panel 7 to be inspected.

  Next, the locus of light at the time of inspection in the lighting inspection apparatus will be described. The light emitted from the backlight 9 passes through the back polarizing plate 8 and the panel to be inspected 7 in this order, and is irradiated from the illumination unit to the inspection unit. Unnecessary light is shielded by the light shielding cover 4 and the remaining measurement light enters the area sensor 1 through the strip-shaped surface polarizing plate 6 supported by the surface polarizing plate pressing jig 5.

FIG. 2 is a schematic view of the area sensor mount 3 in a state where no strip-shaped surface polarizing plate is installed as seen from the front. From the front, the area sensor mount 3, the light shielding cover 4, and the surface polarizing plate pressing jig 5 can be seen.
(Line configuration and inspection method)
FIG. 3 is a schematic view showing a production line in which the lighting inspection apparatus according to the present invention is installed. In the figure, three panel conveying devices 10 are arranged in succession, and the panel 7 to be inspected is sequentially conveyed from the left to the right by the conveying roller 11. In the center of the figure, the area sensor pedestal 3 is installed in front of the panel transfer device 10, which is the area sensor pedestal 3 shown in FIG. Here, FIG. 1 is a cross-sectional view of the central portion of FIG.

  The flow of inspection in this line configuration is as follows. That is, the panel to be inspected 7 is transported from the left panel transport device 10 in FIG. 3 to the central panel transport device 10. The central panel transport apparatus 10 holds the panel 7 to be inspected, and uses an inspection panel drive signal generator (not shown) and a contact jig for transmitting the panel drive signal to send an inspection drive signal to the panel 7 to be inspected. The panel to be inspected 7 is turned on. The area sensor 1 shown in FIG. 1 takes an image of the panel to be inspected 7, inspects it using an image picked up by nine cameras in an inspection processing section (not shown), and outputs the inspection result to an output device (not shown). To do. The area sensor 1 shown in FIG. 1 has nine units, and each area sensor picks up an image of the panel 7 to be inspected at the same time by picking up an image of a region 12 that divides the panel 7 to be inspected, as shown in FIG. Therefore, the entire panel of the panel to be inspected 7 can be imaged collectively. With regard to the inspection content, when the panel 7 to be inspected is lit black, a pixel that shines brightly even though it should be dark is extracted as a defect, and information such as the position and brightness of the defect is output. There are cases where a dark picture element is extracted as a defect even though it should be bright when it is lit. The inspection content is not limited to such items.

  FIG. 5 is a schematic diagram showing the positional relationship between the back polarizing plate 8 and the strip-shaped front polarizing plate 6 that are necessary for inspection with respect to the liquid crystal panel that is assumed as the panel to be inspected 7 and is not yet attached to the polarizing plate. Here, a vertical arrow is described on the back polarizing plate 8, which means that the back polarizing plate 8 has a property of transmitting the polarized light in the vertical direction and has a vertical polarization axis direction. become. Similarly, the strip-shaped surface polarizing plate 6 has a horizontal arrow, which has a property of transmitting polarized light in the horizontal direction and has a horizontal polarization axis direction. As described above, each picture element becomes dark when the panel 7 to be inspected is lit black. This is because when the panel to be inspected 7 is black, the panel 7 to be inspected transmits the polarized light in the vertical direction that has passed through the back polarizing plate 8 from the backlight 9 without changing the polarization direction. The strip-shaped surface polarizing plate 6 transmits only the polarized light in the lateral direction, and therefore becomes dark because there is no transmitted light. Conversely, when the panel to be inspected 7 is lit white, each picture element becomes white. This is because when the panel 7 to be inspected is white, the panel 7 to be inspected is polarized by 90 degrees with respect to the vertically polarized light that has passed through the back polarizing plate 8 from the backlight 9. Since the strip-shaped surface polarizing plate 6 has a property of transmitting the polarized light in the horizontal direction, the light is transmitted through in place of the polarized light in the direction. In other words, the defective picture element operates to change the polarization direction due to defective manufacture of a picture element that should not change the polarization direction, or the polarization direction due to defective manufacture of a picture element that should polarize the polarization direction by 90 degrees. For example, a bright spot on a black-lit screen and a dark spot on a white-lit screen are generated due to a difference in the amount of transmitted polarized light when operating correctly.

That is, in order to perform inspection correctly, it is important to accurately cross the polarization axis direction of the back polarizing plate and the polarization axis direction of the front polarizing plate with high accuracy. Depending on the type of the liquid crystal panel, there is a liquid crystal panel in which the polarization axis direction of the back polarizing plate and the polarization axis direction of the front polarizing plate are made parallel. The positional relationship between the polarization axis direction of the back polarizing plate and the polarization axis direction of the front polarizing plate in the configuration of the present invention is not limited to orthogonal and horizontal, but is determined depending on the type and design of the liquid crystal panel. It is.
(Configuration of surface polarizing plate pressing jig and strip surface polarizing plate replacement method)
FIG. 6 shows a schematic diagram of a polarizing plate installation jig. As shown in FIG. 1, in front of each area sensor, a light shielding cover 4, a surface polarizing plate pressing jig 5, and a strip-shaped surface polarizing plate 6 are installed to constitute a polarizing plate installation jig. FIG. 6 is an enlarged view of the light shielding cover 4 and the surface polarizing plate pressing jig 5, and two surface polarizing plate alignment pins 13 are installed on the light shielding cover 4. The jig 5 is fixed by the stopper 15 so as not to rattle. Further, an opening 14 is provided at the center of the light shielding cover 4 and the surface polarizing plate pressing jig 5, and the panel 7 to be inspected is picked up by the area sensor 1 shown in FIG.

  Next, the installation method of the strip-shaped surface polarizing plate 6 is demonstrated using FIG. FIG. 7 is a view of the polarizing plate installation jig as viewed from the direction A in FIG. In this lighting inspection apparatus, three identical area sensors 1 are arranged in a straight line in the depth direction of the paper, and three polarizing plate installation jigs are also arranged in a straight line in the depth direction of the paper. In order to cover the three area sensors arranged in a straight line with one strip-shaped surface polarizing plate, one strip-shaped surface polarizing plate is set on the three polarizing plate setting jigs arranged in a straight line.

  FIG. 7A shows a state where a strip-shaped surface polarizing plate is not attached. First, as shown in FIG. 7 (b), the surface polarizing plate pressing jig 5 is removed from the stopper 15 installed on the light shielding cover 4.

  Next, as shown in FIG. 7 (c), the strip-shaped surface polarizing plate 6 is positioned and installed using the surface polarizing plate alignment pin 13. At this time, the strip-shaped surface polarizing plate 6 is in contact with a total of six surface polarizing plate alignment pins 13 installed on three surface polarizing plate pressing jigs on the long side. For this reason, the long side direction of the strip-shaped surface polarizing plate 6 is always the direction in which the surface polarizing plate alignment pins 13 are arranged. Here, since the polarizing plate in which the angle between the polarizing axis direction and the long side direction of the polarizing plate is constant is used as the strip-shaped surface polarizing plate 6, the strip-shaped surface polarizing plate installed in the surface polarizing plate pressing jig. The polarization axis direction 6 is positioned on the lighting inspection device with high accuracy. Since the polarization axis direction of the back polarizing plate is positioned in advance in the lighting inspection device, the crossing angle between the polarization axis direction of the strip-shaped front polarizing plate and the polarization axis direction of the back polarizing plate is in a predetermined state.

  Finally, as shown in FIG. 7D, the surface polarizing plate pressing jig 5 is closed and fixed to complete the installation of the surface polarizing plate 6.

  FIG. 8 is a view of the state after the installation is completed as viewed from the light incident side. In FIG. 8, the strip-shaped surface polarizing plate 6 is installed using the strip-shaped surface polarizing plate 6 that is long in the horizontal direction and covers three area sensors.

  FIG. 9 is a schematic view of the area sensor mount 3 as viewed from the light incident side after the installation of the strip-shaped surface polarizing plate 6 is completed. As described above, the surface polarizing plates 6 of all nine area sensors can be replaced only by replacing the three strip-shaped surface polarizing plates 6. Further, by using the surface polarizing plate alignment pin 13 shown in FIG. 6, the front polarizing plate 6 can be fixed with the polarization axis direction aligned with a predetermined direction easily and with high accuracy.

In this embodiment, the area sensors are arranged in 3 rows and 3 columns, but the present invention is not limited to this, and any configuration may be used as long as a plurality of area sensors are arranged in a straight line. Moreover, although the surface polarizing plate alignment pin 13 was installed in two polarizing plate installation jigs, the positioning jig is not limited to this. For example, in a plurality of polarizing plate installation jigs arranged in a straight line, a configuration in which two surface polarizing plate alignment pins are installed as a whole, or across a plurality of polarizing plate installation jigs arranged in a straight line as shown in FIG. Alternatively, a single linear polarizing plate alignment bar 16 may be installed. In this embodiment, the polarizing plate installation jig is composed of a light shielding cover, a surface polarizing plate pressing jig, and a surface polarizing plate alignment pin, but is not limited to this, and holds the strip-shaped surface polarizing plate. Any configuration may be used as long as it has a positioning jig capable of positioning the strip-shaped surface polarizing plate. For example, a strip-shaped surface polarizing plate may be sandwiched and supported by a supporting member that does not have a light shielding function and a surface polarizing plate pressing jig.
(Effects in lighting inspection equipment)
The problem in the case where the surface polarizing plate 20 is installed for each of the nine area sensors will be described with reference to FIGS. 10 and 11. FIG. 10 shows a state in which the surface polarizing plate 6 for one area sensor is installed. FIG. 11 is a schematic view of the area sensor mount 3 as viewed from the light incident side after the installation of the surface polarizing plate 20 is completed. Here, the distance between the two surface polarizing plate alignment pins 13 in FIG. 10 is 200 mm, and the distance between the two surface polarizing plate alignment pins 13 in FIG. 9 is 700 mm. Assuming that the installation accuracy of the surface polarizing plate alignment pin 13 has an error of 1 mm, in the installation method shown in FIG. 11, the deviation from the horizontal direction of the polarization axis direction is arctan (1/200), which is about 0.28 degrees. It becomes. On the other hand, in the method shown in FIG. 9, the deviation of the polarization axis direction from the horizontal direction is arctan (1/700), which is about 0.08 degrees. That is, the method according to the present invention can increase the installation accuracy in the direction of the polarization axis by about three times.

  Further, considering the labor for replacing the polarizing plate, the method shown in FIG. 9 according to the present invention requires only three replacement operations per apparatus, but the method shown in FIG. 11 requires nine replacement operations. In general, when a plurality of lines are operated simultaneously in the process, if 20 lines are operated and two main inspection apparatuses are installed in each line, the method shown in FIG. 9 × 20 × 2 = 360 replacement operations are required. On the other hand, in the method according to the present invention shown in FIG. 9, 3 × 20 × 2 = 120 replacement operations are sufficient at the time of periodic replacement. Assuming that the work time per replacement work is 10 minutes, (360 times-120 times) × 10 minutes leads to a reduction of the total work time of 2400 minutes (40 hours). I can expect.

  In this embodiment, the description has been given using the strip-shaped surface polarizing plate extending in the horizontal direction, but the strip-shaped polarizing plate extending in the vertical direction has a structure as shown in FIG. 12, and the same effect can be expected. In this embodiment, the panel to be inspected is transported in an upright state. However, the transport mode is not limited to this, and for example, horizontal transportation is possible. In this case, the area sensor is placed on the surface of the panel to be inspected. Installed face to face.

4 Shading cover 5 Surface polarizing plate holding jig 6 Strip-shaped surface polarizing plate 7 Panel to be inspected 8 Back polarizing plate 13 Front polarizing plate alignment pin 16 Front polarizing plate alignment bar

Claims (2)

Consists of two or more area sensors, area sensor mounts, strip-shaped surface polarizing plate, back polarizing plate, backlight, and inspection processing unit,
A liquid crystal panel lighting inspection apparatus in which light transmitted through a single strip-shaped surface polarizing plate is incident on a plurality of area sensors,
The area sensor mount has a polarizing plate installation jig for installing the strip-shaped surface polarizing plate,
The said polarizing plate installation jig has a positioning jig which contact | abuts at the long side of the said strip-shaped surface polarizing plate, The liquid crystal panel lighting test | inspection apparatus characterized by the above-mentioned.   The liquid crystal panel lighting inspection apparatus according to claim 1, wherein the arrangement direction of the plurality of area sensors is one direction, and the arrangement direction and the arrangement direction of the polarizing plate installation jig coincide with each other.

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