JP2014202818A - Method for repairing defect of liquid crystal display panel, and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device relieving a defect and improving a yield by facilitating light shielding of a black matrix missing part at a panel-periphery frame part detected during manufacture of a liquid crystal display panel, and retaining the high definition by making the missing part invisible even after completion of the product.SOLUTION: The defect repair method for a liquid crystal display panel 50 includes, when a missing part 12 is formed in a black matrix 3 of a panel-periphery frame part, forming a repair light-shielding area 13 on the surface of a polarizer 7 stuck to a TFT array substrate 52 in such a manner as to include an area on which the missing part 12 is projected on the polarizer 7.

Description

  The present invention relates to a defect repair method for a liquid crystal display panel according to a liquid crystal display device, and a liquid crystal display device using the same.

The display unit of the conventional liquid crystal display device has a polarizing plate pasted on the surface of the lower transparent glass substrate and the surface of the upper transparent glass substrate on a liquid crystal display panel in which the liquid crystal is sandwiched between the lower and upper transparent glass substrates superimposed. (Refer to Patent Document 1 and FIG. 1).
In the liquid crystal display panel, a TFT array pattern for driving liquid crystal is formed on the liquid crystal sealing surface of the lower transparent glass substrate, and a black matrix (hereinafter referred to as BM) is formed on the liquid crystal sealing surface of the upper transparent glass substrate. It is formed as a light shielding film that blocks light leaking between adjacent pixels of the substrate and from the peripheral frame portion.

By the way, there is a defect of the BM as one factor for decreasing the yield of the liquid crystal display panel. In particular, in order to block the light from the backlight behind the panel, pinholes of more than several μm, color loss, peeling, etc. occur in the BM provided in the frame portion of the display unit, and light leakage occurs. This is a very noticeable defect for liquid crystal display device viewers. Therefore, defect inspection and repair are performed as part of improving the yield of liquid crystal display panels.
As an example of repair, a method of forming a pseudo-light-shielding film with a negative photosensitive resin with a size that matches the size of a defective portion on the surface of a transparent glass substrate having BM and covering the defective portion with a pinpoint is well known (Patent Literature). 1, see FIG.
However, in this repair method, the light is shielded when viewed from the front direction. However, when viewed from an oblique direction, there is a problem that the light leaked from the defective portion is visually recognized without being shielded.
In addition, when a pseudo-light-shielding film is formed on the surface of the transparent glass substrate, it is sandwiched as a foreign object between the polarizing plate attached from above. There is a problem that it is visually recognized as unevenness, or a convex portion is formed on the surface of the polarizing plate, and it becomes visible even after the product is completed, and the quality is lowered.

Furthermore, it is said that a pseudo light-shielding film is formed on the surface of the TFT array substrate with a negative photosensitive resin to cover the defective portion with a pinpoint. However, in the conventional TFT array substrate, the TFT portion facing the BM is a metal. Therefore, sufficient exposure cannot be performed. Therefore, when a pseudo light-shielding film is formed on the surface of the TFT array substrate, a film (liquid) that easily changes in state is formed, resulting in an insufficient light-shielding state.
In addition, the formation of a pseudo light-shielding film on the surface of a transparent glass substrate by light exposure requires a specific apparatus configuration because it is necessary to immerse in a developing solution in order to remove the resin other than the cured portion. There is a problem that the defect cannot be repaired.

  As another example of the BM repair method, Patent Document 2 is well known. This repair method is a method in which a black ink composition is applied to a portion corresponding to a defect portion on the surface side of a transparent glass substrate (upper transparent glass substrate) having BM (see Patent Document 2, FIG. 2, and FIG. 3). .

JP 10-48616 PR (Fig. 1) JP2011-12205 PR (FIGS. 2 and 3)

As in the above Patent Document 2, when a pseudo light-shielding film is formed on the surface of a transparent glass substrate having BM, it is sandwiched as a foreign substance between the polarizing plate attached from above as described above. There is a problem in that an abnormal region of the polarization axis is partially generated and visually recognized as unevenness, or a convex portion is formed on the surface of the polarizing plate, and becomes visible even after the product is completed and the quality is lowered.
Moreover, when a defective part is detected after polarizing plate attachment in the manufacturing process of the liquid crystal display panel, it is necessary to peel off the attached polarizing plate and apply a black ink composition, which causes a loss cost. There is a point.

  The present invention has been made to solve the above-described problems, and can easily shield BM defects in the frame peripheral portion of the panel detected during the manufacturing process, and perform defect relief and yield improvement. An object of the present invention is to provide a display device that maintains its quality by making it invisible after completion.

  In the defect repair method for a liquid crystal display panel according to the present invention, a first substrate in which a light shielding film is formed in a frame portion around a display region of a transparent glass substrate, and a plurality of pixels are arranged in a matrix in the display region of the transparent glass substrate. A liquid crystal is sandwiched between the first substrate and the second substrate so as to circulate the display region, and the liquid crystal is not in contact with the liquid crystal on the first substrate. In the liquid crystal display panel in which the first polarizing plate is attached to the surface side and the second polarizing plate is attached to the surface side of the second substrate that is not in contact with the liquid crystal, a missing portion is generated in the light shielding film. In this case, the defect repairing method is characterized in that a light-shielding region for repair is formed on the surface of the second polarizing plate so as to include the region where the missing portion is projected on the second polarizing plate. And

  According to the present invention, it is possible to easily shield BM missing from the peripheral frame portion of the panel detected during the manufacturing process of the image display panel, to perform defect repair and yield improvement, and to be invisible even after the product is completed. By doing so, a display device with high quality can be provided.

It is a top view which shows the outline of the liquid crystal display panel in Embodiment 1 which concerns on this invention. It is a schematic sectional drawing of the liquid crystal display panel in Embodiment 1 which concerns on this invention. It is a schematic sectional drawing of the liquid crystal display panel which shows the example of a change in Embodiment 1 which concerns on this invention. It is a schematic sectional drawing of the liquid crystal display panel in Embodiment 2 which concerns on this invention. It is a schematic sectional drawing of the liquid crystal display panel in Embodiment 3 which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In order to avoid redundant descriptions, the same reference numerals are given to elements having the same or corresponding functions in each drawing.

Embodiment 1 FIG.
FIG. 1 is a top view schematically showing a liquid crystal display panel 50 which is a main constituent member of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a III-III direction along the one-dot chain line shown in FIG. It is the figure which extracted a part of cross section seen from. In the liquid crystal display panel 50 shown in FIGS. 1 and 2, a first substrate 51 (hereinafter referred to as a counter substrate) includes a polarizing plate (first polarizing plate) 1, a transparent glass substrate 2, a peripheral frame portion black matrix. (Hereinafter referred to as a peripheral frame portion BM) 3, an in-plane black matrix (hereinafter referred to as an in-plane BM) 4, a color material 5, and a counter electrode (not shown). The second substrate (hereinafter referred to as a TFT array substrate) 52 includes a polarizing plate (second polarizing plate) 7, a transparent glass substrate 8, an array routing wiring 9, a pixel electrode 10, and a TFT 11. The TFT array substrate 52 and the counter substrate 51 sandwich the liquid crystal 6 with an appropriate gap by the sealing material 14 that goes around the display region 53 in which the pixel electrodes 10 are arranged in a matrix. Here, the counter electrode, the pixel electrode 10 and the TFT 11 for driving the counter electrode constitute one pixel, and are the minimum unit for controlling the display together with the liquid crystal 6 between the counter electrode and the pixel electrode 10. Further, in each of the counter substrate 51 and the TFT array substrate 52, polarizing plates 1 and 7 are attached to the surface side that does not contact the liquid crystal 6.

  In the present embodiment, a case where a missing portion 12 in which a light shielding film is partially missing occurs at a specific location of the peripheral frame portion BM3 is illustrated. The peripheral frame portion BM3 shown in FIG. 2 is formed of a film using a metal (for example, chromium: Cr) as a material or a film using a light-shielding resin as a material. When these light-shielding films are partially missing due to variations in the formation process during the film-formation exposure process (for example, when the film is not partially deposited by a foreign substance), a state like a missing part 12 is formed, resulting in a defect.

  In the liquid crystal display panel 50 exemplified in the present embodiment, a backlight (not shown) is arranged at a predetermined position on the polarizing plate 7 side (not shown), and is visually observed from the polarizing plate 1 side when lit and displayed. In addition, since the most common normally white mode (eg TN liquid crystal) is adopted as the liquid crystal display panel, the peripheral frame portion BM3 blocks the light generated during the lighting display in the frame region of the display region. Has a role to play. Accordingly, when the missing portion 12 occurs, white light (the missing portion 12) is visually recognized in the black background (light-shielding region), and this becomes a high-contrast region having a large contrast. Depending on the size and shape of the missing portion 12, a display defect (point defect) that is clearly visually recognized in various shapes such as a dot shape and a line shape.

  Therefore, in FIG. 2, 23 to 33% of an acrylic resin blended with black paint and propylene glycol monomethyl meter at a position directly opposite to the missing portion 12 on the surface of the polarizing plate 7 attached to the TFT array substrate 52. 10-20%, isobutyl alcohol 45-55%, isopropyl alcohol 10-20%, ethanol 1-10% as a component (for example, Tuffy: TF-8147K-2, manufactured by Hitachi Chemical Co., Ltd.) It is dripped to form a light-shielding region 13 for repair having a larger area than the missing portion 12 and is naturally cured. Here, as shown in FIG. 2, it is important that the outer shape of the light-shielding region 13 for repair sufficiently includes a region (projection state indicated by a broken line in FIG. 2) where the missing portion 12 is projected onto the polarizing plate 7. It is.

  That is, the light-shielding region 13 for repair formed as described above does not leak light even if the viewer visually recognizes the missing portion 12 from not only the front but also from a predetermined oblique direction (for example, 45 degrees oblique). A sufficient area can be easily secured so that it cannot be visually recognized. Thus, the liquid crystal display device using the liquid crystal display panel in which the light-shielding region for repair 13 is formed turns on or reduces the leaked light caused by the missing portion 12 when it is turned on and is not visually recognized as a defect. .

  Furthermore, the method for forming the light-shielding region 13 for repair according to the present embodiment is a method in which a light-shielding resin is dropped and applied to the surface of the polarizing plate 7, and a film can be easily formed without using a special device. Further, there is no partial polarization axis abnormality (visible as unevenness) due to the rising of the polarizing plate, and no deterioration in quality due to the convex portion of the polarizing plate surface. Further, it is not necessary to peel off the polarizing plate 7, and loss cost can be reduced.

  As described above, by forming the light-shielding region 13 for repair on the surface of the polarizing plate 7 on the TFT array substrate 52 side, it is possible to easily shield the BM missing from the peripheral frame portion of the panel and complete the product as a liquid crystal display device. Since it is not visually recognized later, a display device with high quality can be provided, and defect relief and yield improvement can be performed.

[Example of change]
FIG. 3 shows a modification example when the light-shielding region 13 for repair is formed on the surface of the polarizing plate 7 with a metal component (for example, silver: Ag).

  As in the first embodiment, a light-shielding film is applied to the surface of the polarizing plate 7 to form the repairing light-shielding region 13. In this embodiment mode, silver paste is used as the light-shielding film. The silver paste is a conductive adhesive obtained by mixing silver powder as a conductive filler in an epoxy resin, and has a sufficient light shielding property. As a result, it is possible to easily shield the BM missing at the peripheral frame portion of the panel and not to be visually recognized after the assembly of the liquid crystal display device. Therefore, it is possible to provide a display device with high quality, and to improve defect repair and yield. Yes.

Embodiment 2. FIG.
FIG. 4 shows an example in which a light-shielding film is formed on the polarizing plate 1 side on the counter substrate 51 side as the repairing light-shielding region 13 on the surface of the polarizing plate 1 according to the present embodiment. FIG. 4 is a diagram in which a part of the cross section is extracted as in the first embodiment.
The method for forming the light-shielding region 13 for repair is application to the polarizing plate 1 by dripping a resin having light-shielding properties as in the first embodiment, and the leakage light from the missing portion 12 is blocked and is not visually recognized as a defect. . A special apparatus is not required and can be easily formed. The polarizing plate 1 does not need to be peeled off, and the loss cost can be reduced.

  The light-shielding region 13 for repair in the present embodiment is a light-shielding film applied to the polarizing plate 1 on the side where the viewer visually recognizes the liquid crystal display device, and the applied light-shielding film is easily visually recognized, but is shown in FIG. As described above, it is possible to employ the light-shielding region 13 for repair in the missing portion 12 generated in the region that is not visually recognized due to the arrangement of the front bezel 54 of the liquid crystal display device. As shown in FIG. 4, the front bezel 54 is usually made of metal, and due to its light shielding property, leakage light from the missing portion 12 cannot be visually recognized from the front of the liquid crystal display device. This is particularly effective when the leaked light is visually recognized when a gap with the liquid crystal display panel 50 is visually recognized, resulting in a defect.

Embodiment 3 FIG.
FIG. 5 shows an example applied to an IPS liquid crystal display device. As in the first embodiment described above, by forming the light-shielding region 13 for repair on the surface of the polarizing plate 7, it is possible to easily shield the BM missing from the frame peripheral portion of the panel, and it is not visually recognized even after the product is completed. Accordingly, a display device with high quality can be provided, and defect relief and yield improvement can be performed.
In addition, FIG. 5 is a diagram in which a part of the cross section is extracted as in the first embodiment.

  The IPS liquid crystal display device generally adopts a normally black mode. However, even in the peripheral frame region, the frame region is affected by the leakage electric field from the pixel portion and the potential applied to the array routing wiring 9. In some cases, the liquid crystal does not exhibit a completely light-shielded state but a so-called black floating state. In this case, the light from the black floating is blocked by the light shielding by the peripheral frame portion BM3, and the separation between the display area and the peripheral frame area becomes clear, and a high-quality liquid crystal display device is obtained. However, when the missing portion 12 occurs in the peripheral frame portion BM3, the light in the black floating state (the missing portion 12) is visually recognized in the peripheral frame region, and the visual quality is deteriorated. On the other hand, as in the first embodiment, the formation of the light-shielding region 13 for repair on the surface of the polarizing plate 7 makes it possible to easily shield the BM missing from the peripheral frame portion of the panel, even after the liquid crystal display device is completed. The defect of the black floating state is not visually recognized.

  As described above, the present invention exemplified in the first and second embodiments can be easily applied to various liquid crystal modes including the IPS method, the FFS method, the VA method and the ECB method which are normally white modes. Applicable.

1, 7 Polarizing plate 2, 8 Transparent glass substrate 6 Liquid crystal 3 Peripheral frame portion black matrix (peripheral frame portion BM)
12 missing portion 13 light-shielding region for repair 14 sealing material 50 liquid crystal display panel 51 first substrate (counter substrate)
52 Second substrate (TFT array substrate)
53 display area

Claims (6)

A first substrate having a light shielding film formed on a frame portion around the display area of the transparent glass substrate;
A second substrate having a plurality of pixels arranged in a matrix in a display area of a transparent glass substrate,
A sealing material is disposed between the first substrate and the second substrate so as to circulate the display region, and the liquid crystal is sandwiched between the first substrate and the first polarizing plate on the surface side not contacting the liquid crystal of the first substrate. In the liquid crystal display panel in which the second polarizing plate is attached to the surface of the second substrate that is not in contact with the liquid crystal, a defect repairing method when a missing portion occurs in the light shielding film. ,
A defect repairing method for a liquid crystal display panel, characterized in that a light-shielding region for repair is formed on the surface of the second polarizing plate so as to include the region where the missing portion is projected on the second polarizing plate. .   A backlight is disposed at a predetermined position with respect to the liquid crystal display panel, and the light-shielding area for repair having a sufficient area so that leakage light is not visible even when viewed from a predetermined oblique direction is formed. The defect repairing method for a liquid crystal display panel according to claim 1.   3. The defect repairing method for a liquid crystal display panel according to claim 1, wherein the light-shielding region for repair is formed by dripping a light-shielding resin onto the second polarizing plate.   3. The method for repairing a defect in a liquid crystal display panel according to claim 1, wherein the repairing light-shielding region is formed by dropping silver paste onto the second polarizing plate.   5. The method for repairing a defect in a liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is a liquid crystal display panel adopting a normally black mode.   The liquid crystal display device using the defect repair method of the liquid crystal display panel as described in any one of Claims 1-5 with respect to a liquid crystal display panel.

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