JPH05210074A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To improve display grade by providing a light shielding means in the region corresponding to a defective picture element on an optical path for incident light and exit light. CONSTITUTION:The regions where a full-surface electrode 4 and picture element electrodes 6 overlap are formed as the picture element regions in this liquid crystal display device 1. The picture element electrode 6a cannot impress a normal driving voltage to a corresponding liquid crystal layer 8 by a disconnection of wirings of the characteristic defect of a TFT, etc. The region A1 including the picture element electrode 6a is thus a defective picture element region. This defective picture element region A1 can make only the display to allow the transmission of the light regardless of the impression/non-impression of the voltage to the picture element electrode 6 and, therefore, the surrounding picture element regions shut off the light but the light transmits in the defective picture element region A1 and forms a bright spot in this region when the voltage is impressed to the surrounding picture element electrodes 6. The degraded display grade is then resulted. The light shielding means 9 is, thereupon, provided in the defective picture element region A1. Then, there is no more transmission of the light in the defective picture element region A1 and the formation of the bright spot is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device for correcting defects such as bright spots of defective pixels and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, a liquid crystal display panel has been used in a projection device for enlarging and projecting an image on a screen. In this projection device, display illumination light is emitted from one surface of a transmissive liquid crystal panel in which display pixels are arranged in a matrix, and output light emitted from the other surface is enlarged and projected on a screen to display an image. ..

As an example of the liquid crystal panel used in the above-mentioned projection device, there is an active matrix drive type liquid crystal panel. In this liquid crystal panel, TFTs (thin film transistors) are connected to pixel electrodes arranged in a matrix on one of a pair of translucent substrates such as glass to be bonded, and switching operation of the TFTs is performed. A display operation is performed by selecting and deselecting each pixel electrode. For this reason, crosstalk during non-selection, which is a drawback of the simple matrix driving method, does not occur, and a high-quality display screen can be realized.

Since the TFT has a multi-layer structure in which a gate electrode, a source electrode, a drain electrode, etc. are laminated on a substrate, a step of laminating these metal thin films on the substrate,
The step of patterning the metal thin film is repeated. Therefore, in order to manufacture a complete TFT without defects, great effort is required to maintain and manage various setting conditions in each manufacturing process.

Therefore, in some cases, a normal TFT
A defective TFT whose characteristics are not obtained may occur, and a defect that can be repaired can be repaired by using each repairing technique depending on the content of the defect. Such T
As an example of an FT defect, a pixel corresponding to a pixel electrode connected to a TFT becomes a bright point and is recognized as a bright spot on a display screen when the circuit formation pattern cannot be repaired and the display is driven. There is a point defect.

In order to prevent the occurrence of defective pixels as described above, conventionally, for example, two wirings are connected to each pixel electrode, and even if one wiring is damaged, the display is not affected. I am trying. Further, each pixel is divided into two and one pixel is displayed by a plurality of electrodes, and when it is not possible to apply a voltage to one electrode, the remaining electrode is used to display the pixel.

[0007]

In a liquid crystal display device in which two wirings are connected to each pixel or one pixel is divided into two and one pixel is displayed by a plurality of electrodes, the driving circuit is complicated. Therefore, there is a problem that it is difficult to design and manufacture a circuit. Further, since the circuit becomes complicated and the number of wirings increases, the area for forming the wirings must be increased, the area of each electrode is reduced, and the display brightness is reduced.

Further, when one pixel is displayed by a plurality of electrodes, there is a problem that a driving circuit for displaying is burdened.

Further, even when the conventional technique as described above is used, if any of the two wirings connected to each pixel is damaged, it is connected to each of the plurality of electrodes for displaying one pixel. If each wiring is damaged,
The occurrence of bright spots cannot be prevented.

It is an object of the present invention to provide a liquid crystal display device which prevents light from leaking from a region corresponding to a defective pixel and improves display quality, and a method of manufacturing the same.

[0011]

The present invention provides a liquid crystal display device in which a plurality of pixels are formed in a matrix with a liquid crystal layer interposed between a pair of translucent substrates, and on the optical paths of incident light and emitted light. The liquid crystal display device is characterized in that a light shielding unit is provided in a region corresponding to a defective pixel.

Further, according to the present invention, in a method of manufacturing a liquid crystal display device in which a liquid crystal layer is interposed between a pair of transparent substrates, and a plurality of pixels are formed in a matrix, at least one of the pair of transparent substrates is provided. On the other hand, a coating means is formed on the surface of the substrate opposite to the liquid crystal layer, and is on the optical path of the incident light and the emitted light
Further, the method is characterized in that a recess is formed in a region corresponding to a defective pixel on a side of the one substrate on which the coating means is formed, the recess is filled with a light-shielding resin, and the coating means is peeled off. A method for manufacturing a liquid crystal display device.

[0013]

According to the present invention, the light leaking from the region corresponding to the defective pixel is blocked by the light shielding means provided in the region corresponding to the defective pixel on the optical paths of the incident light and the outgoing light. Therefore, it is possible to prevent light from leaking from the region corresponding to the defective pixel, and it is possible to significantly improve the display quality.

Further, according to the invention, a coating means is formed on a surface of at least one of the pair of translucent substrates constituting the liquid crystal display element, the surface being opposite to the liquid crystal layer. Form a recess in the area corresponding to the defective pixel,
A liquid crystal display device is formed by filling the recess with light-shielding resin and finally peeling off the covering means. As a result, the light leaking from the area corresponding to the defective pixel is blocked by the light shielding resin filled in the recess provided in the area corresponding to the defective pixel. Therefore, it is possible to prevent light from leaking from the region corresponding to the defective pixel and improve the display quality of the liquid crystal display device.

Further, when the recess is filled with the light-shielding resin, the resin overflows around the recess, and when the overflowing resin is removed, the resin is excessively filled by the thickness of the covering means. Therefore, by adjusting the thickness of the coating means,
The thickness of the resin filled in the recess can be removed so that the central portion does not become thin, and the thickness of the light-shielding resin can be adjusted in a state of being raised from the substrate surface.

[0016]

1 is a sectional view showing the structure of a liquid crystal display device 1 according to an embodiment of the present invention. In the liquid crystal display device 1, transparent substrates 2 and 3 having a light-transmitting property made of glass or the like are arranged so as to face each other. A single full-scale electrode 4 is formed, and an alignment film 5 made of a resin such as polyimide is further formed on the surface thereof. A plurality of solid pixel electrodes 6 are arranged in a matrix on the surface of the transparent substrate 3 facing the transparent substrate 2, and an alignment film 7 is formed on the surface of the pixel electrodes 6.

The transparent substrates 2 and 3 are arranged such that the surfaces on which the electrodes 4 and 6 are formed face each other, and a liquid crystal layer 8 is interposed between the substrates. A TFT (not shown) is connected to each of the pixel electrodes 6.

In the liquid crystal display device 1, a region where the entire surface electrode 4 and the pixel electrode 6 overlap each other is a pixel region. In the present embodiment, the pixel electrode 6a has a wiring disconnection or T
A normal drive voltage cannot be applied to the corresponding liquid crystal layer 8 due to defective FT characteristics or the like, and the area A1 including the pixel electrode 6a becomes a defective pixel area. The defective pixel area A1
Can display only light, regardless of whether or not a voltage is applied to the pixel electrode 6a. Therefore, when a voltage is applied to the surrounding pixel electrode 6, the surrounding pixel region blocks light, but the defective pixel region A1
Since it transmits light, it becomes a bright spot and the display quality is degraded. In the present invention, as shown in FIG.
By providing the light blocking means 9 to the defective pixel area A
The light does not pass through 1 and is prevented from becoming a bright spot.

The light shielding means 9 may be formed on the substrate 3 or may be formed on both the substrates 2 and 3.

FIG. 2 is a diagram for explaining an example of use of the liquid crystal display device 1. Here, the liquid crystal display device 1 is used as a display panel of a so-called projection display device. Light from a light source 11 (not shown) is emitted from the condenser lens 1
Light incident from the transparent substrate 2 side of the liquid crystal display device 1 which is a display panel via 2 and emitted from the transparent substrate 3 side is applied to a screen (not shown) via the projection lens 13. As a result, the image displayed on the liquid crystal display device 1 is enlarged and projected on the screen.

At this time, a light shielding means 9 is provided on the optical path of the incident light to the defective pixel area A1 as shown in FIG. 1, and the incident light is shielded. Therefore, the emitted light 14 from the defective pixel area A1 is not irradiated on the screen and is not displayed as a bright spot in the enlarged and projected image.

As described above, in the liquid crystal display device 1 of the projection type display device, even if the bright spot is small, the image is enlarged, so that the bright spot is also enlarged and displayed on the screen. Therefore, by providing the light blocking means 9 in the area corresponding to the defective pixel area A1 and blocking the incident light as in the present invention, it is possible to prevent the bright display from being enlarged. As a result, the display quality of the image is significantly improved.

FIG. 3 is a plan view of the liquid crystal display device 1.
As shown in FIG. 3A, the light shielding means 9 is a square that covers the pixel electrode 6a. The light-shielding means 9 has a length of 150 μm.
m, width 150 μm, depth 100 μm. Also,
As shown in FIG. 3B, it may be circular, or may have any other shape as long as it includes the pixel electrode 6a.

FIG. 4 is a process drawing for explaining the manufacturing process of the liquid crystal display device 1, and FIG. 5 is a sectional view for explaining the manufacturing method of the liquid crystal display device 1. In this embodiment, FIG.
As shown in (1), the case where the light shielding means 9 is formed on the transparent substrate 2 side will be described.

In step a1, as shown in FIG. 5 (2),
The covering member 16 is formed on almost the entire surface of the transparent substrate 2. In this embodiment, the covering member 16 has a thickness of 50 μm.
A cellophane tape of about m is attached to the surface of the transparent substrate 2 with an adhesive or the like.

In step a2, as shown in FIG.
By irradiating an excimer laser or the like, the recess 17
To form. The recess 17 has, for example, a length of 150 μm and a width of 1
50 μm and a depth of 100 μm are selected.

In step a3, as shown in FIG.
For example, the ink 18 containing the ultraviolet curable resin is applied to the recess 17
Fill inside. Then, in step a4, as shown in FIG. 5 (5), the ink 18 overflowing on the covering member 16 is wiped off. In step a5, the covering member 16 is peeled off, and then the ultraviolet rays are irradiated to solidify the ink 18, thereby forming the light shielding means 9.

As the material of the covering member 16, various adhesive tapes, photoresist materials, glass, metals and the like can be used, but it is necessary to select a material corresponding to the energy of the excimer laser with respect to the object to be processed.

FIG. 6 is a diagram for explaining another embodiment of the present invention. By adjusting the thickness of the covering member 16, it is possible to adjust the thickness of the ink 18 when the ink is wiped off. Therefore, as shown in FIG.
It is also possible to make the thickness uniform with the surface of the transparent substrate 2, and by selecting a relatively large thickness of the covering member 16, as shown in FIG.
It is also possible to form a raised shape from the surface of the.

7 and 8 are diagrams for explaining a comparative example in the present invention. In FIG. 7, the ink 18 containing the ultraviolet curable resin is directly applied onto the defective pixel area A1 of the transparent substrate 2. In the comparative example shown in FIG. 7, the light-shielding means 9 is easily peeled off due to an external factor such as wiping off the dirt on the surface of the transparent substrate 2, and the film thickness is determined by the surface tension of the ink 18, so it can be adjusted. It is also difficult to make the thickness of the entire film uniform.

In FIG. 8, a recess is directly formed on the transparent substrate 2 without forming the covering member 16, and the recess is filled with the ink 18 containing the ultraviolet curable resin. In the comparative example shown in FIG. 8, if the amount of ink to be filled is too small, the result shown in FIG.
As shown in (3), it is not possible to sufficiently fill the recesses with the ink 18, so it is necessary to fill the recesses with a relatively large amount of ink. In this case, the ink 18 overflows from the recess as shown in FIG. At this time, as shown in FIG. 8C, the ink 18 in the central portion of the recess is also wiped off at the same time. Therefore, as shown in FIG. It is very difficult to form the means 9, and a sufficient film thickness cannot be secured.

Since the size of the recess is determined corresponding to the pixel of the liquid crystal display device, it is usually several tens of μm to one hundred and several tens μm.
Chosen by the corner.

FIG. 9 is a side view of the recess forming device 30 used for forming the recess 17. The laser beam 32 emitted from the laser oscillator 31 passes through the slit pattern 33 in which the pattern of the outer shape of the recess 17 formed on the defective pixel region A1 is formed, and is reflected by the ultraviolet reflection mirror 34. After that, the light is focused and irradiated onto the defective pixel region A1 of the liquid crystal display device 1 mounted on the mounting table 36 through the lens 35.

The laser beam 32 is used for the slit pattern 3
Since the reduction slit exposure is performed via 3, the defective pixel area A
The position 1 is accurately irradiated. Further, although it is difficult to form the blocking piece 6 in a shape corresponding to the rectangular defective pixel area A1, it is possible to form the recess 17 in a rectangular shape by using the slit pattern 33, and to reduce the formation area. be able to. The mounting table 36 is movable in, for example, two XY orthogonal directions in a horizontal plane, and the laser beam 32 can be irradiated onto a desired defective pixel area A1 by the movement of the mounting table 36.

FIG. 10 is a view showing a light-shielding means installation device 20 used in the present invention, and FIG.
11 is a diagram showing a step b1 of FIG. 1, and FIG. 10 (2) is a diagram showing a step b5 of FIG.

A sliding member 41 that slides along the rail 40 is installed on the lower surface side of the rail 40 that is horizontally installed by the frame 49. The sliding range of the sliding member 41 on the rail 40 is defined by the two stoppers 42a and 42b installed on the rail 40.

A supporting member 43 is installed on the sliding member 41 toward the lower side in FIG.
A sliding piece 44 is installed slidably in the vertical direction of 0. A needle 45 is installed on the sliding piece 44 downward in FIG.

One end of the spring 46 is connected to the sliding member 41, and the other end of the spring 46 is connected to the sliding piece 44. The sliding piece 44 is biased by a spring 46 toward the sliding member 41.

A table 48 is installed below the above-mentioned structure in FIG. On the table 48, a container 47 containing the ink 18 that serves as the light shielding unit 9 and the liquid crystal display device 1 having the defective pixel area A1 are installed. The ink 18 contains an ultraviolet curable resin and is a liquid before the ultraviolet irradiation treatment.

The container 47 is installed at a position where the sliding member 41 is brought into contact with the stopper 42a and the sliding piece 44 is lowered so that the ink 18 adheres to the needle 45. Further, the liquid crystal display element 1 is installed so that the sliding member 41 is brought into contact with the stopper 42b, the sliding piece 44 is lowered, and the defective pixel area A1 is located at a position P where the needle 45 comes into contact.

FIG. 11 is a process chart for explaining the process of installing the light shielding means 9 using the blocking piece installation device 20 shown in FIG. In step b1, as shown in FIG. 10 (1), the sliding member 41 is slid to a position in contact with the stopper 42a. At this position, the needle 45 is located on the ink 18. In step b2, the sliding piece 44 is lowered to attach the ink 18 to the tip of the needle 45.

In step b3, when the sliding member 41 is brought into contact with the stopper 42b and the sliding piece 44 is lowered, the needle 45
The defective pixel area A of the liquid crystal display device 1 at the position P where
The liquid crystal display device 1 is positioned so that 1 comes.

In step b4, the sliding member 41 is attached to the stopper 4
2b until it comes into contact, and in step b5, as shown in FIG.
As shown in (2), the sliding piece 44 is lowered to bring the tip of the needle 45 into contact with the defective pixel area A1 to attach the ink 18.

Then, the ink 18 is irradiated with ultraviolet rays to be cured. The ink 18 is hardened and fixed on the liquid crystal display device 1.

The size of the light-shielding means 9 formed is the same as that of the needle 45.
Is arbitrarily selected depending on the tip shape and thickness of the ink, the film thickness of the ink 18 in the container 47, and the like.

As described above, according to this embodiment, by blocking the optical path of the light passing through the defective pixel area A1,
It is possible to prevent light from leaking from the defective pixel and improve the display quality.

[0047]

As described above, according to the present invention, the light leaking from the region corresponding to the defective pixel is shielded by the light shielding means provided in the region corresponding to the defective pixel on the optical paths of the incident light and the outgoing light. To be done. Therefore, it is possible to prevent light from leaking from the region corresponding to the defective pixel, and it is possible to significantly improve the display quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a liquid crystal display device 1 which is an embodiment of the present invention.

FIG. 2 is a diagram for explaining an example of use of the liquid crystal display device 1.

3 is a plan view of the liquid crystal display device 1. FIG.

FIG. 4 is a process drawing for explaining the manufacturing method of the liquid crystal display device 1.

FIG. 5 is a cross-sectional view for explaining the method of manufacturing the liquid crystal display device 1.

FIG. 6 is a diagram for explaining another embodiment of the present invention.

FIG. 7 is a diagram for explaining a comparative example in the present invention.

FIG. 8 is a diagram for explaining a comparative example in the present invention.

9 is a side view of the recess forming device 30. FIG.

FIG. 10 is a side view of the shading device installation device 20.

FIG. 11 is a process diagram illustrating a method of forming a light shielding unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2,3 Transparent electrode 4 Full surface electrode 5,7 Alignment film 6 Pixel electrode 8 Liquid crystal layer 9 Light-shielding means 16 Covering member 17 Recess A1 Defective pixel area

Claims (2)

[Claims] 1. A liquid crystal layer is interposed between a pair of transparent substrates,
A liquid crystal display device in which a plurality of pixels are formed in a matrix, wherein a light shielding unit is provided in a region corresponding to a defective pixel on an optical path of incident light and emitted light. 2. A liquid crystal layer is interposed between a pair of transparent substrates,
In a method of manufacturing a liquid crystal display device in which a plurality of pixels are formed in a matrix, a coating means is formed on a surface of at least one of the pair of translucent substrates opposite to a liquid crystal layer, and incident light and emitted light are provided. On the optical path of the one substrate, and on the side of the coating means forming surface of the one substrate, a recess is formed in a region corresponding to the defective pixel, the recess is filled with a light-shielding resin, and the coating means is peeled off. A method of manufacturing a liquid crystal display device, comprising: