JP2004233184A - Polarizing plate application accuracy inspection method of liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting polarizing plate application accuracy capable of preventing generation of a defective product by inspecting automatically the polarizing plate application accuracy to a liquid crystal panel without applying processing to the liquid crystal panel, corresponding easily to the change of a panel size, and also improving inspection efficiency and heightening efficiency of a production process of the liquid crystal panel by inspecting simultaneously the application state of two polarizing plates on both faces of the liquid crystal panel. <P>SOLUTION: In this polarizing plate application accuracy inspection method of the liquid crystal panel performed after applying the polarizing plate 3 onto the liquid crystal panel 1, some of four corners of the liquid crystal panel 1 or the periphery of a plurality of edge parts is photographed by CCD cameras 28, 29 from the direction orthogonal to the liquid crystal panel 1 side face, and the distance from the liquid crystal panel 1 end to the polarizing plate 3 end in the photographed image is measured by image processing, and if the distance is in a specified range, the panel is determined to be a nondefective product. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for inspecting the accuracy of attaching a polarizing plate attached to a liquid crystal panel. More specifically, an accuracy inspection device is incorporated immediately after the attaching device for a polarizing plate, and after attaching the polarizing plate, the attachment is inspected immediately from the cross section of the polarizing plate. And a method for performing the method.
[0002]
[Prior art]
FIGS. 10A and 10B are configuration diagrams of a liquid crystal panel (liquid crystal cell) to which a polarizing plate is attached. FIG. 10A is a plan view, and FIG. 10B is a side sectional view of a part of the liquid crystal panel. The panel 1 is configured by sealing liquid crystal (not shown) at the boundary between the two glass substrates 2, 2, and further includes polarizing plates 3 on both outer surfaces of the bonded glass substrates 2, 2. , 3 are attached to form a liquid crystal cell.
[0003]
In the manufacturing process of the liquid crystal unit, a conventional method of attaching the polarizing plate 3 to the liquid crystal panel 1 is performed by using a polarizing plate 3 having an adhesive layer provided on one surface in advance and using the adhesive layer to form a liquid crystal panel. It is to be attached to 1.
[0004]
The position where the polarizing plate 3 is attached to the liquid crystal panel 1 is required to have high accuracy, and the alignment is performed by using an alignment mark 4 provided on the glass substrate 2 side. Pasting is performed while positioning automatically.
[0005]
However, even if the positioning is automatically performed by the sticking device, the sticking position may be shifted due to a timing shift of the device or the like. If the accuracy of the sticking is not checked after the sticking operation, the sticking position of the polarizing plate 3 may be shifted. The liquid crystal panel 1 may flow to the next process, and if the position where the polarizing plate 3 is stuck is shifted, there is a problem that the liquid crystal panel 1 cannot be incorporated into an outer frame in a later process, or a defective display of pixels. Such a problem had occurred.
[0006]
Therefore, all or sampling is performed after pasting the polarizing plate, and the position of the polarizing plate is measured by observing the peripheral edge of the polarizing plate with a microscope and confirming the positional deviation after pasting. A reading method and the like are performed.
[0007]
Further, there is a method in which a marker for confirming the position of a polarizing plate attached to a substrate is provided to enable visual confirmation of the attached position by checking whether or not the pasted polarizing plate is inside the mark (for example, see Patent Document 1). 1).
[0008]
By the way, the above-mentioned methods are manually performed manually and are costly. In addition, one sheet is used for inspecting the state of each of the two polarizing plates attached to the front and back surfaces of the liquid crystal panel. There is a problem that two inspections are required for the liquid crystal panel, which is troublesome.
[0009]
In addition, in the method of sampling and inspecting, there is a time lag until a defect is found after the polarizing plate is pasted, and when there is a trouble on the pasting device, the discovery thereof is delayed, and a large number of defective products may be generated. .
[0010]
For defective products generated here, the polarizing plate is peeled off and re-attached, but it takes enormous effort and there is a case where it is impossible to reproduce due to peeling mistakes, and these are obstacles to improvement in yield. I was
[0011]
In addition, manual inspection requires time and cost, and with the recent improvement in the performance of liquid crystal panels, the demand for sticking accuracy has been increasing, making it difficult to handle manual inspection.
[0012]
In the method of tracing with a dial gauge, the liquid crystal panel comes into contact with the liquid crystal panel at the time of inspection, so that static electricity may be transmitted to the liquid crystal panel to damage the liquid crystal, or the panel may not be able to cope with an increase in panel size.
[0013]
Therefore, there has been proposed a method in which a slit for checking the accuracy of attachment is provided on a transparent insulating substrate so that automation can be performed, and a polarizing plate attachment position is inspected from above the surface with a CCD or the like through the slit (for example, Patent Document 1). 2).
[0014]
This method performs slit processing at a predetermined position of the glass substrate, and determines whether the polarizing plate is shifted from the slit or not, and determines whether or not the polarizing plate is pasted. The inspection can be performed by automatic inspection using an optical inspection device.
[0015]
[Patent Document 1]
JP-A-5-216021 (FIGS. 1 to 3)
[0016]
[Patent Document 2]
JP-A-10-90673
[0017]
[Problems to be solved by the invention]
However, even the method of providing a slit for confirmation on a transparent insulating substrate and automatically inspecting with a CCD as in Patent Document 2 described above has the following problems.
[0018]
In other words, this method requires processing on the liquid crystal panel substrate side and cannot be applied to all liquid crystal panels, and also has a problem that a liquid crystal display portion becomes narrower than the entire substrate in order to secure a space for slits.
[0019]
Accordingly, an object of the present invention is to automatically inspect the accuracy of attaching a polarizing plate to a liquid crystal panel in the same manufacturing process as before without processing the liquid crystal panel such as providing a slit for confirmation, thereby generating defective products. It is another object of the present invention to provide a method for inspecting the accuracy of attaching a polarizing plate, which can prevent the occurrence of a problem, and can easily cope with a change in panel size, and can improve the efficiency of a liquid crystal panel production process.
[0020]
Another object of the present invention is to provide an inspection method capable of simultaneously inspecting the state of attachment of two polarizing plates attached to both sides of a liquid crystal panel and improving the inspection efficiency.
[0021]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first aspect of the present invention is a method for inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel after attaching the polarizing plate to the liquid crystal panel using an adhesive layer provided on one surface of the polarizing plate. In one or more of the four corners of the liquid crystal panel or the vicinity of a plurality of edges is photographed by a CCD camera from a direction perpendicular to the side surface of the liquid crystal panel, and from the liquid crystal panel end to the polarizing plate end in the photographed image. This is a method of inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel, which measures a distance by image processing and determines that the liquid crystal panel is non-defective if the distance is within a specified range.
[0022]
According to the above configuration, since the CCD camera photographs the edges (corners) of the four corners of the liquid crystal panel in a direction perpendicular to the side surface (cross section) of the panel, an image of the glass substrate constituting the liquid crystal panel is included in the image. The edge and the edge of the polarizing plate are simultaneously imaged, and by analyzing this image, the distance from the edge of the glass substrate to the edge of the polarizing plate in the horizontal direction along the side surface of the liquid crystal panel is obtained.
[0023]
In order to obtain the horizontal distance along the side of the liquid crystal panel from the image, the CCD camera shoots the image from the vertical direction with respect to the side of the liquid crystal panel. You may take pictures from a slightly oblique direction.
[0024]
If the distance between the edge of the two polarizing plates and the edge of the glass substrate at the four corner edges of the liquid crystal panel determined by the image analysis is within a predetermined range, the liquid crystal panel will have a polarizing plate within the specified precision. If the distance is out of the predetermined range, the liquid crystal panel can be determined to be a defective product in which the accuracy of attaching the polarizing plate is out of the specified range.
[0025]
Immediately after attaching the polarizing plate to the liquid crystal panel, it is possible to determine whether the attaching position is within the appropriate range and to flow only good products to the next process, eliminating the need for a process for inspecting the attaching position of the polarizing plate. In addition, if it is determined that a defective product has occurred, the attaching device is stopped and the defective product can be discharged to the discharge area. This can improve yield and reduce costs.
[0026]
In addition, since the present invention takes an image from a direction perpendicular to the side surface of the panel, the two polarizing plates attached to the front and back surfaces of the glass substrate are simultaneously imaged and each polarizing plate is viewed from the end of the glass substrate. Since the distance can be determined at the same time, if the image is taken after attaching two polarizing plates, a quick inspection can be performed without the trouble of turning over the liquid crystal panel during the inspection.
[0027]
The four corners of the liquid crystal panel can be photographed by moving one CCD camera or by changing the position by rotating the liquid crystal panel. If the photographing is performed at the same time, the accuracy test can be performed more quickly.
[0028]
The invention according to claim 2 is a method for inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel after attaching the polarizing plate to the liquid crystal panel using an adhesive layer provided on one surface of the polarizing plate. Or a plurality of edges are photographed by a CCD camera from a direction perpendicular to the side of the liquid crystal panel by a CCD camera, and the position of the end of the polarizing plate in the photographed image is obtained by image processing, and the liquid crystal panel recognized by a separate means. This is a polarizing plate sticking accuracy inspection method in which a distance from the position of the alignment mark for positioning to the end of the polarizing plate is calculated, and if the distance is within a specified range, the polarizing plate is determined to be non-defective.
[0029]
In the first aspect of the present invention, the distance to the edge of the polarizing plate is determined based on the edge of the liquid crystal panel obtained by the CCD camera. Using the position information and the like of the upper alignment mark, the distance from the end of the polarizing plate obtained by the CCD camera is obtained to inspect the polarizing plate sticking accuracy.
[0030]
The separate means for recognizing the position of the alignment mark on the liquid crystal panel includes the above-described position information of the alignment mark recognized by a CCD camera separately prepared at the time of positioning the liquid crystal panel, and a polarizing plate. Whether a CCD camera is provided in the plane direction (upper or lower part of the liquid crystal panel) of the pasting accuracy inspection unit, or whether the CCD camera for photographing the side surface of the liquid crystal panel used for this inspection is moved so that it can be photographed from the plane direction. Then, the position of the alignment mark may be recognized by photographing from the liquid crystal panel plane direction, and this method is not particularly limited.
[0031]
This method is preferably used when the end face accuracy of the glass substrate of the liquid crystal panel is not so good and it is inappropriate to use as a reference for the position of the polarizing plate.
[0032]
According to a third aspect of the present invention, in the first or second aspect of the present invention, a CCD camera is disposed slightly outside the end of the position where the polarizing plate is to be pasted on the liquid crystal panel. This is a method of inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel, which focuses and photographs the vicinity of an edge.
[0033]
According to the above configuration, the CCD camera is slightly outside the edge of the position where the polarizing plate is to be pasted, that is, the edge of the liquid crystal panel is not right beside but slightly oblique (a range where the measurement error due to parallax does not affect). Both edges on one side enter the field of view of the CCD camera, and even when the polarizing plate is attached at an angle, the far edge in the field of view of the CCD camera may be hidden behind the near edge. Instead, a single CCD camera can be used to capture images near two edges.
[0034]
In this case, since it is necessary that the focus of the CCD camera is adjusted to two edges in the near and far directions, it is preferable to apply the present invention to a small liquid crystal panel in which the distance between the two edges seen from the CCD camera is relatively small.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0036]
FIG. 1 is a plan view showing an entire device for attaching a polarizing plate to a liquid crystal panel according to the present invention.
[0037]
As shown in the figure, the polarizing plate sticking apparatus includes a liquid crystal panel 1 made of a glass substrate and a polarizing plate 3 attached to one surface of the liquid crystal panel 1, and a polarizing plate 3 attached to the other surface of the liquid crystal panel 1. The processing line of the polarizing plate 3 for separating the release paper from the adhesive surface of the polarizing plate 3 and the polarizing plate attaching line for attaching the polarizing plate 3 to the liquid crystal panel 1 are respectively divided on the horizontal machine base 11. Are provided in parallel.
[0038]
A polarizing plate supply position a and a release sheet peeling position b are set on the processing lines of the polarizing plates 3 in the first and second stages, and a liquid crystal panel supply position c in the first stage is set on the polarizing plate attaching line. In the subsequent stage, a liquid crystal panel supply position c, a polarizing plate bonding position d, and a liquid crystal cell inspection / discharge position f are set, respectively.
[0039]
A liquid crystal panel supply line 12 faces the liquid crystal panel supply position c of the polarizing plate attaching line in the preceding polarizing plate attaching apparatus, and the liquid crystal panel 1 that has gone through the cullet removing and cleaning steps supplies the liquid crystal panel to the liquid crystal panel supplying line 12. It is sent to position c.
[0040]
Similarly, a polarizing plate storage box 13 for storing the polarizing plates 3 in a stacked state is provided at the polarizing plate supply position a of the processing line of the polarizing plate 3 in the preceding polarizing plate attaching apparatus.
[0041]
Two (not shown) cylindrical brushes 14 facing each other and appropriate positioning means (not shown) are provided between the polarizing plate supply position a and the release paper peeling position b. The surface of the polarizing plate 3 conveyed from the position a to the release sheet peeling position b is removed by passing between the two brushes 14, and is subsequently positioned by a suitable positioning means (not shown). It has become.
[0042]
Further, a release paper peeling device 16 for releasing the release paper from the polarizing plate 3 by the release paper release roller 15 is provided at the release paper release position b.
[0043]
Further, the polarizing plate 3 supplied and positioned from the polarizing plate storage box 13 is attracted and held on the upper surface thereof, and the release paper is peeled off by the release paper peeling device 16 to expose the surface adhesive layer. A polarizing plate suction table 17 for transferring to a polarizing plate sticking position d of the polarizing plate sticking line is arranged.
[0044]
The dust and flaws on the surface of the polarizing plate 3 that are attracted and transferred to the polarizing plate suction table 17 between the release sheet peeling position b of the polarizing plate processing line and the polarizing plate sticking position d of the polarizing plate sticking line. An inspection device 18 for inspecting whether or not there is any information is provided.
[0045]
The liquid crystal panel 1 sent by the liquid crystal panel supply line 12 is sucked and held on its upper surface at the liquid crystal panel supply position c of the preceding polarizing plate sticking line, and the liquid crystal panel supply table 19 that moves up a predetermined stroke after this suction. Is disposed below the polarizing plate sticking position d so that the sticking roller 20 is moved up and down by the elevating means. In the liquid crystal panel discharging position e, the liquid crystal panel 1 on which the polarizing plate is stuck on the upper surface is also placed. A liquid crystal panel discharge table 21 for holding by suction is provided.
[0046]
When the polarizing plate 3 sucked and held by the polarizing plate suction table 17 is transferred from the release sheet peeling position b to the polarizing plate sticking position d, if it is determined by the inspection of the inspection device 18 that it is a non-defective product, the polarizing plate sticking position d The liquid crystal panel 1 on which the polarizing plate 3 is adhered on one side is transferred to the liquid crystal panel discharge table 21 at a liquid crystal panel discharge position e, and the liquid crystal panel discharge table 21 further applies appropriate means from the liquid crystal panel discharge table 21. And supplied to the liquid crystal panel supply table 19 at the subsequent stage.
[0047]
The liquid crystal panel transferred to the liquid crystal panel supply table 19 in the subsequent stage moves from the liquid crystal panel supply position c in the subsequent stage to the polarizing plate sticking position d, and performs the same processing steps as those in the preceding polarizing plate attaching operation again. The polarizing plate 3 is also stuck on the other surface on which the first polarizing plate 3 is not stuck yet.
[0048]
In the release paper peeling position b, the release paper peeling device 16 in the preceding stage is arranged such that the release roller 15 moves in the horizontal direction with respect to the polarizing plate 3 to peel off the release paper 5 in the drawing. In the subsequent release paper peeling device 16, the release roller 15 is fixed and the release paper 5 is peeled off as the polarizing plate 3 moves. However, any of the release paper peeling devices may be used for both the former and latter stages. The same release paper peeling device 16 can be used in the latter stage.
[0049]
The liquid crystal panel 1 (liquid crystal cell) having the polarizers 3 bonded on both sides is sent to the liquid crystal cell inspection / discharge position f by the polarizing plate 3 being bonded at the polarizing plate bonding position d in the subsequent stage. The bonding state of the polarizing plates 3 on both sides is inspected by the plate bonding state inspection device 27, non-defective products are sent to the liquid crystal cell discharge line 36, and defective products are discharged to the defective product discharge section 34.
[0050]
It should be noted that the polarizing plate pasting state inspection device 27 and the defective product discharging unit 34 are also provided at the front stage, and the pasting condition of the polarizing plate 3 is inspected every time one side of the polarizing plate is pasted. It may be configured to discharge to the non-defective product discharge area. However, from the viewpoint of shortening the inspection time and the cost of the inspection apparatus, it is preferable to perform the inspection after attaching the polarizing plates to both surfaces as shown in the figure.
[0051]
FIG. 2 is a front view taken along the arrow II of FIG. 1, and the pressure-sensitive adhesive layer is exposed on the other surface of the liquid crystal panel 1 on which the polarizing plate 3 has been pasted on one surface at the preceding polarizing plate pasting line. 3 shows the entirety of a polarizing plate sticking line at a subsequent stage where the second polarizing plate 3 is stuck.
[0052]
As shown in the drawing, the liquid crystal panel 1 is sucked and held by the lower surface on the upper part of the polarizing plate sticking line, and the liquid crystal cell inspection is performed just above the liquid crystal panel supply table 19 at the liquid crystal panel supply position c and the liquid crystal cell inspection / discharge position f. A liquid crystal panel suction table 22 that horizontally reciprocates directly above a table 26 is disposed. The liquid crystal panel suction table 22 is stopped at the liquid crystal panel supply position c, and the liquid crystal panel supply table 19 is lifted up. When the liquid crystal panel 1 held on the upper surface of the panel supply table 19 is pressed against the lower surface of the liquid crystal panel suction table 22 and the liquid crystal panel suction table 22 sucks the liquid crystal panel 1, the liquid crystal panel supply table 19 releases the suction and moves to the lowered position. I will return.
[0053]
Here, the alignment mark 4 of the liquid crystal panel 1 is recognized by an appropriate photographing means (not shown), and the liquid crystal panel 1 is positioned by appropriately driving the suction table 22 based on the recognition data.
[0054]
Next, the liquid crystal panel suction table 22 on which the liquid crystal panel 1 is sucked on the lower surface moves to the polarizing plate sticking position d and stops, and the above-described polarizing plate suction table 17 moves directly below the liquid crystal panel suction table 22. The liquid crystal panel 1 sucked by the suction table 22 and the newly supplied polarizing plate 3 on the polarizing plate suction table 17 are vertically opposed at the polarizing plate sticking position d.
[0055]
The function of attaching the polarizing plate 3 to the liquid crystal panel 1 will be described. First, as shown by a two-dot chain line in FIG. The tip is made to approach the lower surface of the liquid crystal panel A, and in this state, the sticking roller 20 is raised by operating the cylinder 24, and the end of the polarizing plate 3 protruding from the polarizing plate suction table 17 is attached to the liquid crystal panel 1 by the sticking roller 20. Then, the suction of the polarizing plate 3 by the polarizing plate suction table 17 is set to be weak, and the pressing force of the sticking roller 20 and the movement of the liquid crystal panel suction table 22 are prevented while preventing the polarizing plate 3 from falling off the inclined polarizing plate suction table 17. Due to the horizontal movement of the liquid crystal panel 1 accompanying the above, the polarizing plate 3 is attached to the liquid crystal panel 1 with the surface adhesive layer of the polarizing plate 3.
[0056]
The pressing force of the cylinder 24 that pushes up the sticking roller 20 is controlled by the load sensor 25.
[0057]
The liquid crystal panel 1 (liquid crystal cell) on which the polarizing plates 3 have been pasted on both surfaces is transferred to the liquid crystal cell inspection / discharge position f through the polarizing plate pasting process of the first and second stages.
[0058]
When the liquid crystal panel suction table 20 stops at the liquid crystal cell inspection / discharge position f, the liquid crystal cell inspection table 26 rises, receives the liquid crystal panel 1 with the polarizing plate 3 stuck from the liquid crystal panel suction table 22, and returns to the lowered position. The panel suction table 22 returns to the liquid crystal panel supply position c.
[0059]
At the liquid crystal cell inspection / discharge position f at the subsequent stage, the liquid crystal panel 1 is transferred from the liquid crystal panel suction table 22 to the liquid crystal cell inspection table 26, and the polarization plate adhesion state inspection device 27 inspects the position where the polarizing plate 3 is attached. .
[0060]
The liquid crystal cell inspection table 26 is set to have a slightly smaller area than the liquid crystal panel 1, and the liquid crystal panel 1 is fixed by an appropriate means such as suction while the peripheral portion of the liquid crystal panel 1 projects outward from the liquid crystal cell inspection table 26. I have.
[0061]
As shown in a plan view near the liquid crystal cell inspection / discharge position f in FIG. 3 and a side view in FIG. 4 (along arrow II-II in FIG. 1), the liquid crystal cell inspection device on the front side of the liquid crystal cell inspection table 26. Reference numeral 27 denotes CCD cameras 28 and 29 arranged on both sides near the front edge of the liquid crystal panel 1 after the polarizing plates 3 are attached to both sides. The vicinity of the portion is photographed in a direction perpendicular to the side surface of the liquid crystal panel 1, and the photographed image near the edge portion is sent to an image processing device (FIG. 5) disposed separately. .
[0062]
The CCD cameras 28 and 29 incorporate a half mirror 31 inside a cylindrical body 30 provided in the photographing direction, irradiate light from a fiber illumination 32 or the like to the liquid crystal panel 1 side with the half mirror 31, and an edge portion of the liquid crystal panel 1. (Coaxial epi-illumination) for detecting the state of light, and a halogen lamp, ultraviolet light, xenon lamp, or the like can be used as the light source 33 for irradiating the transmitted light.
[0063]
The light emitted from the light source 33 and turned into the fiber illumination 32 is reflected by the half mirror 31, exits from the cylindrical body 30, is reflected by the edges of the glass substrate 2 and the polarizing plate 3, enters the cylindrical body 30 again, and passes through the half mirror 31. After passing through, they are input to the CCD cameras 28 and 29 and captured as analog signal images.
[0064]
FIG. 5 shows a general block diagram of the inspection processing performed by the inspection device 27. This analog signal is converted into a digital signal by A / D conversion, and is used in real time as a filter for noise removal or the like. After being processed and further image-processed, the image is displayed on a monitor by an image display device, and at the same time, the distance from the edge (end) of the glass substrate 2 to the edge (end) of the polarizing plate 3 is changed by the host computer. Is measured, and the quality of the pasting position is determined based on whether the distance is within a predetermined range.
[0065]
FIG. 6 is a plan view showing an example of a state in which the polarizing plate is attached. FIG. 6A shows a liquid crystal in which the polarizing plate 3 is attached to the liquid crystal panel 1 with an accuracy within a specified range from a reference value, that is, in a normal state. (B) shows a case where the polarizing plate 3 is stuck obliquely shifted from the reference position indicated by the dotted line, and (C) shows a cell shifted in parallel from the reference position indicated by the dotted line. In this case, the position shift amount of the polarizing plate 3 is more emphasized than the actual position in order to facilitate understanding.
[0066]
When inspecting the displacement of the polarizing plate 3, the glass substrate 2 (which constitutes the liquid crystal panel 1) and the polarizing plate 3 are rectangular and have the same shape and the same size. By inspecting the distance dimension between the two sides in the vertical and horizontal directions of the surrounding four sides, it is possible to determine what position the polarizing plate 3 is in the glass substrate 2.
[0067]
That is, the horizontal distance a between the end of the glass substrate 2 and the end of the polarizing plate 3 near the lower right edge of the liquid crystal panel 1 shown in each of FIGS. ₁ A horizontal distance a between the edge of the glass substrate 2 and the edge of the polarizing plate 3 near the upper right edge of the liquid crystal panel 1 ₂ The vertical distance b between the end of the glass substrate 2 and the end of the polarizing plate 3 near the lower left edge of the liquid crystal panel 1 ₁ And the vertical distance b between the edge of the glass substrate 2 and the edge of the polarizing plate 3 near the lower right edge of the liquid crystal panel 1 ₂ If the four dimensions are known, the position of the polarizing plate 3 on the glass substrate 2 can be determined.
[0068]
a ₁ , A ₂ , B ₁ , B ₂ 6A are within a specified range from a reference value determined in the case of FIG. 6A, and in FIG. 6B, one or more dimensions are outside the specified range from the reference value. In the case of (C), a ₁ , A ₂ Is within the specified range from the reference value, but b ₁ , B ₂ Is out of the specified range from the reference value. Therefore, when the four dimensions are within the specified range from the reference value, the polarizing plate 3 is at a normal position and can be determined as a good product.
[0069]
Next, a description will be given of a method of measuring the dimensions in the inspection unit. First, as a first-stage accuracy inspection, a side surface (cross-section) of the liquid crystal panel 1 using coaxial epi-illumination as shown in FIGS. The two CCD cameras 28 and 29 are focused on the edge of the image and an image of the edge is captured.
[0070]
FIG. 7 shows a display of a liquid crystal screen obtained by the CCD camera 28. The monitor displays the ends of the upper and lower glass substrates 2, 2 and the polarizers 3, 3 near the edge of the liquid crystal panel. The edge is projected in a step-like manner, the image is subjected to image processing by A / D conversion, and the dimension a from the edge of the glass substrate 2 of the upper polarizing plate 3 is measured. ₁ , And the dimension a ′ of the lower polarizing plate 3 from the end of the glass substrate 2 ₁ It is measured by detecting
[0071]
In the other CCD camera 29, the dimension a from the edge of the glass substrate 2 of the upper polarizing plate 3 near the other edge of the liquid crystal panel is also determined in the same manner. ₂ And the dimension a ′ from the edge of the lower polarizing plate 3 and the glass substrate 2 ₂ Are detected and measured by performing image processing by A / D conversion from the image.
[0072]
In the position information of the upper polarizing plate 3 measured in the first accuracy inspection stage, the dimension a ₁ , A ₂ , And the dimension a ′ in the position information of the lower polarizing plate 3 ₁ , A ' ₂ Based on this information, the host computer determines the quality of the polarizing plate attachment position, and a ₁ , A ₂ , A ' ₁ , A ' ₂ If any one of them is out of the specified range from the reference value, it is discharged as a defective product from the liquid crystal cell inspection / discharge position f to the defective product discharge unit 34 by appropriate means (not shown), and the next accuracy test is performed. If all the values are within the specified range, the process proceeds to the next second-stage accuracy test.
[0073]
By rotating the liquid crystal cell inspection table 26 to the left by 90 degrees by the driving means 35, the liquid crystal panel 1 in which no defect has been detected is so arranged that the front side surface in FIG. Become. Note that the measurement position may be changed by rotating or moving the CCD camera.
[0074]
In the accuracy test of the second stage, the CCD camera 28 on the near side uses the b in each liquid crystal panel 1 shown in FIG. ₁ , B ' ₁ Is b by the CCD camera 29 on the back side. ₂ , B ' ₂ Will be measured.
[0075]
Dimension b of position information of upper polarizing plate 3 ₁ , B ₂ , And the size b of the position information of the lower polarizing plate 3 ₁ , B ' ₂ Based on the information of the above, the host computer determines the quality of the polarizing plate attachment position, and b ₁ , B ₂ , B ' ₁ , B ' ₂ If any one of them is out of the specified range from the reference value, it is discharged as a defective product from the liquid crystal cell inspection / discharge position f to the defective product discharging unit 34 by appropriate means (not shown), and the next process is performed. If they are not within the specified range from the reference value, non-defective non-defective products are conveyed to the liquid crystal cell discharge line 36 as they are, and then the next step is performed.
[0076]
In the first-stage inspection and the second-stage inspection, when a defective product is discharged, the polarizing plate attaching line is stopped at the same time to inspect the polarizing plate attaching device. It is possible to prevent the occurrence of a failure in attaching the polarizing plate due to the cause, thereby preventing a situation in which a large number of defective products are generated.
[0077]
Subsequently, the liquid crystal panel 1 for which the polarizing plate attachment position is determined to be a non-defective product is transferred to a mounting process such as TCP or FPC by the disposed liquid crystal cell discharge line 36.
[0078]
8A and 8B show another example of the accuracy inspection apparatus, wherein FIG. 8A is a plan view, FIG. 8B is a partially enlarged plan view, and one CCD camera is installed. Is an example of a configuration in which is separated.
[0079]
In the case of this embodiment, the CCD camera 37 is disposed slightly shifted (right side in the figure) from an extension of the edge of the polarizer at the position where the polarizing plate 3 is to be pasted on the right side of the liquid crystal panel 1 in the figure. Also in this figure, the amount of displacement of the polarizing plate 3 and the amount of displacement of the installation position of the CCD camera 37 are exaggerated for ease of understanding.
[0080]
Next, a description will be given of a method of measuring the dimensions in the inspection unit. First, as a first-stage accuracy inspection, the illumination 38 is turned on to illuminate one side of the liquid crystal panel 1 as shown in FIG. The image of the edge portion is photographed by focusing the edge of the CCD camera 37 on the edge portion on the near side.
[0081]
Since the shift amount of the CCD camera does not affect the parallax, an image similar to the display on the liquid crystal screen of FIG. 7 obtained in the above embodiment is taken, and the monitor displays the edge portion of the liquid crystal panel 1. The end portions of the upper and lower two glass substrates 2 and 2 and the end portions of the polarizing plates 3 and 3 in the vicinity are projected in a step shape, and the image is subjected to image processing by A / D conversion. Dimension a from end of glass substrate 2 ₁ , And the dimension a ′ of the lower polarizing plate 3 from the end of the glass substrate 2 ₁ Can be measured by detecting
[0082]
Next, the focus of the CCD camera 37 is re-focused on an edge portion on the back side of the CCD camera 37, an image near the edge portion is photographed, and after image processing by A / D conversion, a ₂ , A ' ₂ Is measured.
[0083]
By the way, assuming that the CCD camera is photographed from the direction perpendicular to the side surface of the liquid crystal panel 1 toward the edge portion as in the previous embodiment, the polarizing plate 3 is inclined as shown in FIG. 8B. In this case, the edge on the front side of the polarizing plate 3 hides the edge on the back side with respect to the CCD camera, and the dimension a ₂ Is measured, the apparent distance a due to the influence of the edge on the near side in the image processing. _x However, if the CCD camera 37 is installed as in this embodiment, both edges of the polarizing plate 3 are not disturbed by the other edges. An image will be obtained.
[0084]
It should be noted that the order of photographing near the two edge portions where the distance from the CCD camera 37 is far in the inspection is not particularly limited.
[0085]
Among the positional information of the upper polarizing plate 3 measured in the first-stage accuracy inspection, the dimension a ₁ , A ₂ , And the dimension a ′ in the position information of the lower polarizing plate 3 ₁ , A ' ₂ Based on this information, the host computer determines the quality of the polarizing plate attachment position, and a ₁ , A ₂ , A ' ₁ , A ' ₂ If any one of them is out of the specified range from the reference value, it is discharged as a defective product from the liquid crystal cell inspection / discharge position f to the defective product discharge unit 34 by appropriate means (not shown), and the next accuracy test is performed. If all the values are within the specified range from the reference value, the process proceeds to the next second-stage accuracy inspection.
[0086]
By rotating the liquid crystal cell inspection table 26 to the left by 90 degrees by the driving means 35, the liquid crystal panel in which no defect is detected is such that the left front edge in FIG. 6 becomes the right front side and faces the CCD camera 37. . The measurement position may be changed by rotating or moving the CCD camera 37.
[0087]
Then, as a second-stage accuracy check, the same CCD camera 37 is used to focus on two far and near edges by the same method as the first-stage accuracy check, and b ₁ , B ' ₁ And b ₂ , B ' ₂ Is measured, and the dimension b of the positional information of the upper polarizing plate 3 is obtained. ₁ , B ₂ , And the size b ′ of the position information of the lower polarizing plate 3 ₁ , B ' ₂ Based on the information of the above, the host computer determines the quality of the polarizing plate attachment position, and b ₁ , B ₂ , B ' ₁ , B ' ₂ If any one of them is out of the specified range from the reference value, it is discharged as a defective product from the liquid crystal cell inspection / discharge position f to the defective product discharging unit 34 by appropriate means (not shown), and the next process is performed. If they are not within the specified range from the reference value, non-defective non-defective products are conveyed to the liquid crystal cell discharge line 36 as they are, and then the next step is performed.
[0088]
The inspection apparatus of this embodiment is a method suitable for a small liquid crystal panel because the CCD camera 37 needs to be focused on two edges of the liquid crystal panel at two distances. In some cases, it is difficult to focus on one edge portion. In this case, the dimension a of the edge portion close to the CCD camera 37 in the first stage inspection ₁ , A ' ₁ Only the dimension b of the edge portion near the CCD camera 37 in the second stage inspection ₁ , B ' ₁ Only the measurements are made, and the pass / fail judgment is made only with these dimensions. ₂ , B ₂ , A ' ₂ , B ' ₂ May be measured.
[0089]
Next, a method for measuring the distance to the edge (edge) of the polarizing plate with reference to the position of the alignment mark provided on the glass substrate of the liquid crystal panel to inspect the accuracy will be described. The inspection apparatus shown in FIGS. 3 to 5 and FIG. 8 described above can be used as it is, and the same parts as those in the above-described embodiment are denoted by the same reference numerals.
[0090]
In the above-described embodiment, the video taken from the vertical direction on the side surface of the liquid crystal panel is analyzed, and the distance to the end of the polarizing plate is measured with reference to the end of the glass substrate. The position information of the end of the polarizing plate obtained by analyzing the image taken from the vertical direction on the side surface of the liquid crystal panel with reference to the position information of the alignment mark provided for positioning on the panel side by separate means and using this position as a reference Is calculated.
[0091]
As a means for obtaining the position information of the alignment mark, for example, the position information of the alignment mark recognized for accurate positioning of the liquid crystal panel when the polarizing plate is attached to the liquid crystal panel can be used.
[0092]
First, at the time of attaching the polarizing plate, the position of the liquid crystal panel 1 is recognized by recognizing the positions of the alignment marks 4 provided near the four edges of the glass substrate 2 constituting the liquid crystal panel 1 before attaching the polarizing plate. Is corrected as necessary, and the position information of the alignment mark 4 used in the accuracy inspection is based on the position information obtained at this time.
[0093]
The alignment mark 4 is, for example, provided by being printed on one surface of the glass substrate 2 by means of printing or the like. The alignment mark 4 can be transmitted through the transparent glass substrate 2 and can be recognized from both front and back sides. When is transferred from the supply table 19 to the suction table 22, it can be recognized by a CCD camera or the like provided on the lower side while being suctioned to the suction table 22.
[0094]
If the position of the liquid crystal panel 1 together with the liquid crystal panel suction table 22 is driven to correct at the polarizing plate sticking position d based on the position information of the alignment mark 4, the position information of the alignment mark 4 is also corrected accordingly. .
[0095]
Alternatively, as described above, the position of the alignment mark 4 may be recognized by means different from the means for recognizing at the time of attaching the polarizing plate to the liquid crystal panel. You may make it recognize by means.
[0096]
Since the alignment mark 4 is provided on one surface of the glass substrate 2, it is preferable that the recognizing means be taken by a CCD camera or the like from the vertical direction on the upper or lower surface of the liquid crystal panel. May be provided separately, or may be used by driving from the position for photographing the side surface of the liquid crystal panel to the position for photographing the plane of the liquid crystal panel using the CCD camera 28, 29 or 37 used in the accuracy inspection. Is also good.
[0097]
In the above description, the position recognition by the CCD camera has been described. However, the means for recognizing the alignment mark 4 is not limited to the CCD camera, and any appropriate recognition means conventionally used can be used.
[0098]
In addition, the position for confirming the position of the alignment mark 4 is not limited to the above-described position, and is not particularly limited as long as the position of the liquid crystal panel can be recognized at the time of accuracy inspection.
[0099]
Further, the alignment mark 4 is not limited to the one printed on the glass substrate shown in this embodiment, but may be a concave portion, a convex portion, or a concave portion provided on the glass substrate as long as the position can be recognized by appropriate means. It may be something like a hole or a slit.
[0100]
Thereafter, similarly to the above-described embodiment, a non-defective product and a defective product are identified through a first-stage accuracy test and a second-stage accuracy test.
[0101]
FIG. 9A is a view showing a monitor screen in the first stage of the accuracy test of this embodiment, and a portion shown in a partially enlarged plan view near the edge portion of the liquid crystal panel in FIG. The image taken from the side of the camera is shown.
[0102]
On the monitor, the edges of the upper and lower two glass substrates 2 and 2 and the edges of the polarizing plates 3 and 3 near the edge of the liquid crystal panel are projected in a stepwise manner, and the image is subjected to A / D conversion. The position information of these parts is obtained by recognizing the position of the upper end of the polarizing plate 3 and the position of the lower end of the polarizing plate 3 on an image.
[0103]
The alignment mark 4 is provided on one upper main surface of the glass substrate 2 near the edge of the liquid crystal panel 1 and cannot be recognized by a monitor displaying an image from the side, but is obtained in advance by the separate means described above. The position information of the alignment mark 4 is input to the host computer (FIG. 5) and converted into the position information of the inspection unit. The position information of the upper and lower polarizing plates 3 obtained by the image processing is used as the upper polarizing plate. A from the alignment mark 4 at the three ends ₁ And the dimension a ′ from the alignment mark 4 at the end of the lower polarizing plate 3 ₁ Is calculated.
[0104]
In the same manner, the dimension a from the alignment mark 4 at the end of the upper polarizing plate 3 near the other edge of the liquid crystal panel ₂ And the dimension a ′ from the alignment mark 4 at the end of the lower polarizing plate 3 ₂ Is calculated.
[0105]
Using the distance between the alignment mark 4 and the end of the polarizing plate 3 in a normal state as a reference value, a ₁ , A ₂ , A ' ₁ , A ' ₂ If at least one of them falls outside the specified range from the reference value, it is determined to be defective. If all of them are within the specified range, the process proceeds to the next second accuracy inspection stage.
[0106]
By rotating the detection table 33 to the left by 90 ° by the driving means 35, the liquid crystal panel 1 in which no defect is detected, the front side surface in FIG. 6 comes to face both the CCD cameras 28 and 29. It is to be noted that the measurement position may be changed by rotation or moving means on the CCD camera side as in the other embodiments.
[0107]
In the second stage of the accuracy inspection, the position information of the alignment mark 4 may be obtained again by appropriate means, or may be obtained by adding the information obtained by rotating the alignment mark 4 by 90 ° to the previously obtained position information of the alignment mark 4. Location information.
[0108]
As described above, the details of the accuracy inspection in the first and second stages and the shift to the next process of the liquid crystal panel 1 after the inspection or the discharge to the defective product discharge unit are the same as those in the above-described embodiment. Description is omitted.
[0109]
The accuracy inspection method of this embodiment described above uses the alignment mark 4 instead of the glass substrate 2 as a reference for the positional accuracy of the polarizing plate 3, and is used when the end surface accuracy of the edge portion of the glass substrate 2 is not good. Is effective.
[0110]
【The invention's effect】
As described above, according to the first aspect of the present invention, the accuracy inspection of the polarizing plate attaching position is automated by the CCD camera and its image processing, so that the productivity of the liquid crystal panel is improved.
[0111]
Further, by performing the inspection from the side (cross-sectional) direction of the liquid crystal panel, it is possible to simultaneously inspect the polarizing plates on both sides at the same time, thereby shortening the inspection time and reducing the number of inspection devices.
[0112]
Furthermore, since the inspection is performed immediately after the process of attaching the polarizing plate to the liquid crystal panel is completed, the machine can be stopped immediately when a defective product is generated, and the generation of a large number of defective products due to a device abnormality is eliminated.
[0113]
Also, since it is only necessary to install a CCD camera near the polarizing plate sticking device, a large space is not required for inspection, and it is possible to easily cope with various panels from small to large.
[0114]
Further, since the inspection can be applied to the same liquid crystal panel as before without processing the liquid crystal panel or the like for the inspection, it is possible to flexibly cope with various panels.
[0115]
According to the invention of claim 2, in addition to the above-described effects, the position of the alignment mark used for positioning the liquid crystal panel when attaching the polarizing plate is used as a reference of the accuracy of the attaching position of the polarizing plate. Even if the accuracy of the end face is not good, an accurate accuracy test can be performed.
[0116]
According to the third aspect of the present invention, in addition to the effects of the first and second aspects, two edges of the liquid crystal panel can be photographed by one CCD camera, which contributes to a reduction in equipment cost. be able to.
[Brief description of the drawings]
FIG. 1 is a plan view of an apparatus for attaching a polarizing plate to a liquid crystal panel used in the present invention.
FIG. 2 is an enlarged front view taken along an arrow II of FIG. 1;
FIG. 3 is a plan view showing the inspection apparatus of the present invention.
FIG. 4 is a side view taken along arrows II-II in FIG.
FIG. 5 is a block diagram illustrating an example of an inspection device.
FIGS. 6A, 6B, and 6C are plan views showing an example of a state in which a polarizing plate is attached.
FIG. 7 is a diagram showing an image on an inspection monitor.
8A is a plan view showing another example of the inspection apparatus, and FIG. 8B is a partially enlarged plan view thereof.
9A is a diagram showing an image of an inspection monitor in another inspection method, and FIG. 9B is a partially enlarged plan view near an edge of the liquid crystal panel.
10A is a plan view showing a configuration of a liquid crystal panel, and FIG. 10B is a side sectional view of a part thereof.
[Explanation of symbols]
1 LCD panel
2 Glass substrate
3 Polarizing plate
4 Alignment mark
11 units
12 LCD panel supply line
13 Polarizer storage box
14 brush
15 Release paper release roller
16 Release paper peeling device
17 Polarizing plate adsorption table
18 Inspection equipment
19 LCD panel supply table
20 Sticking roller
21 LCD panel discharge table
22 LCD panel suction table
23 axes
24 cylinders
25 Load sensor
26 Liquid crystal cell inspection table
27 Polarizing plate pasting condition inspection device
28 CCD camera
29 CCD camera
30 cylinder
31 Half mirror
32 fiber lighting
33 light source
34 Defective product discharge section
35 Driving means
36 Liquid crystal cell discharge line
37 CCD camera
38 Lighting
a Polarizer supply position
b Release paper release position
c LCD panel supply position
d Polarizing plate pasting position
e LCD panel discharge position
f LCD cell inspection / discharge position

Claims (3)

In a method of inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel after attaching the polarizing plate to the liquid crystal panel using an adhesive layer provided on one surface of the polarizing plate, a liquid crystal is formed around one or more edges of the four corners of the liquid crystal panel. Photographed by a CCD camera from a direction perpendicular to the side of the panel, the distance from the edge of the liquid crystal panel to the edge of the polarizing plate in the photographed image is measured by image processing, and if the distance is within the specified range, A method for inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel, wherein the method is determined as non-defective. In a method of inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel after attaching the polarizing plate to the liquid crystal panel using an adhesive layer provided on one surface of the polarizing plate, a liquid crystal is formed around one or more edges of the four corners of the liquid crystal panel. Photographed by a CCD camera from a direction perpendicular to the side of the panel, the position of the edge of the polarizing plate in the photographed image is obtained by image processing, and the position of the alignment mark on the liquid crystal panel recognized by separate means A method for inspecting the accuracy of attaching a polarizing plate to a liquid crystal panel, comprising calculating a distance to an end of the polarizing plate, and determining that the product is non-defective if the distance is within a specified range. A CCD camera is arranged slightly outside the end of the position where the polarizing plate is to be pasted on the liquid crystal panel, and the CCD camera focuses and shoots the vicinity of two edges of the liquid crystal panel. Item 3. The method for testing the accuracy of attaching a polarizing plate to a liquid crystal panel according to Item 1 or 2.

Images