JPH0922016A - Cell gap controller and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which embodies uniformly displayed images by controlling the cell gap of a liquid crystal display panel and its control method. SOLUTION: The cell gap controller 10 is composed of a base plate 6, a compression coil spring 7, a first holding means 8 having a first pressure section 11, a second holding means 9 having a second pressure section 12, a conduit 13, a control valve 14, a pressurizing means 15, a pressure reducing means 16, a transparent window 17, a light source 18 generating monochromatic light, etc. Interference fringes A as shown in Fig. (b) are generated in the liquid crystal display panel 1 at the point of time. A user controls and adjusts the cell gap of the liquid crystal display panel in accordance with these interference fringes. Accordingly, the variations in the cell gap of the liquid crystal display panel are decreased and the high-grade displayed images free from unequal luminance are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell gap control device for a liquid crystal display panel used in a device with a liquid crystal monitor and a method for controlling the same, and more specifically, it applies a monochromatic light to the liquid crystal display panel. The present invention relates to a cell gap control device and a control method for controlling the cell gap of a liquid crystal display panel by utilizing interference fringes generated in the cell.

[0002]

2. Description of the Related Art In recent years, with the spread of equipment with a liquid crystal display panel represented by a liquid crystal monitor and a liquid crystal projector, the demand for higher performance of the liquid crystal display panel has increased, and high definition and high image quality of the liquid crystal display panel have been achieved. Is in progress. With respect to this liquid crystal display panel, performance has been advanced mainly in a large-sized liquid crystal panel and a liquid crystal panel for a liquid crystal projector that displays an image enlarged several tens of times, and there is an increasing demand for a more uniform display image. The present invention relates to a cell gap control device and a control method therefor, which are related to high image quality of a liquid crystal display panel, and will be described below with reference to specific examples thereof.

First, the structure of the main part of a conventional liquid crystal display panel will be described with reference to FIG. FIG. 4 is a sectional view showing a main part of the liquid crystal display panel.

In FIG. 4, reference numeral 1 indicates a liquid crystal display panel. The liquid crystal display panel 1 is a counter substrate (upper glass substrate)
2 and a drive substrate (lower glass substrate) 3 in general. Although not shown on the counter substrate 2, in the case of a color liquid crystal panel, R, G and B color filters and a transparent electrode 2 are provided.
A and an alignment film 2b such as a polyimide film are formed. A scan line and a signal line, which are insulated from each other, are formed on the driving substrate 3, and a thin film transistor TFT (Thin Film) is formed at the intersection of the scan line and the signal line by thin film formation and photolithography technology.
Transistor: neither is shown)
The transparent electrode 3a and the alignment film 3b are formed.

Such two glass substrates are arranged so as to face each other with a predetermined gap therebetween, and glass beads (true yarn balls: diameter 0.3 to 0.8 μm) corresponding to the target gap length are sandwiched as spacers 4. And seal material (not shown)
It is composed by joining. Depending on the size of the glass substrate, the spacer 4 has a small area, and in the case of a small area, the gap between the glass substrates is controlled by dispersing about 0.3 wt% in a sealing material (UV curing type adhesive material) that adheres the periphery. ing.

When the area of the glass substrate is large, the glass beads have an average density of 100 beads / mm ² on the glass substrate.
After spraying with, the cell gap is maintained, then a liquid crystal injection hole is secured in the liquid crystal cell, and the periphery of the liquid crystal cell is adhered with a sealant. After that, by injecting the liquid crystal 5 from the injection hole and closing the injection hole with the sealing material, the sealing material is exposed to UV to be sealed,
The liquid crystal display panel 1 is completed. Conventionally, control of the cell gap of such a liquid crystal display panel has been performed by a dedicated device such as a gap material spreader.

To explain the operation of the liquid crystal display panel having such a structure, the alignment films 2b and 3b formed on the counter substrate 2 and the drive substrate 3 are subjected to a rubbing treatment by a predetermined means and then injected. The liquid crystal 5 thus twisted is aligned by being twisted 90 degrees by the action of this rubbing. The liquid crystal 5 has optical rotatory power, and when no voltage is applied, the light emitted by the backlight (not shown) propagates along the liquid crystal molecule axis in the liquid crystal cell and the plane of polarization rotates by 90 degrees. Two polarizing plates are arranged along this optical rotation direction (when normally white),
The incident light is transmitted through the liquid crystal cell as it is, and color is generated according to R, G, and B of the color filters formed on the counter substrate 2.

On the other hand, when a voltage higher than the threshold value is applied to the liquid crystal 5, the liquid crystal 5 stands up in the voltage direction (direction of both glass substrates), the optical activity is lost, the light is blocked, and black display is performed. That is, the incident light is transmitted at a voltage below the threshold, and the light is blocked when a voltage above the threshold is applied to the liquid crystal 5. As described above, the liquid crystal display panel 1 is configured to perform gradation control in image display by a so-called shutter operation that controls transmitted light according to the applied voltage level.

[0009]

The cell gap in the conventional liquid crystal display panel is controlled according to the area of the glass substrate. That is, when the area of the glass substrates is relatively small, the gap between the glass substrates is controlled by dispersing the gap material in the sealing material that adheres the periphery. However, there is a problem that unevenness occurs in the cell gap due to the warp of the glass substrate and the like, which changes the transmitted light of the backlight, resulting in deterioration of the image quality of the liquid crystal display panel. When the area of the glass substrate is large, the gap material is dispersed over the glass substrate to control the gap.However, it takes time and effort to evenly disperse the gap material, and the dispersed gap material causes unevenness. There is a problem that becomes an obstacle to obtaining a uniform display image.

The present invention has been made in consideration of the above points. Even when the area of the glass substrate is relatively small, the cell gap unevenness due to the warp of the glass substrate or the like is uniformly distributed when the area of the glass substrate is large. It is an object of the present invention to provide a cell gap control device and a control method thereof that solve the problem that it is difficult to achieve and realize a uniform display image.

[0011]

In order to solve the above-mentioned problems, in the cell gap control method of the present invention, the first and second holding means for holding the liquid crystal display panel, and the first holding means have the first and second holding means. One pressure section is provided, and the second holding means is provided with a second pressure section. A conduit is connected to the first and second pressure sections, a regulating valve is connected to the conduit, and a pressurizing means and a depressurizing means are connected to the regulating valve. Further, the first holding means is provided with a biasing means for biasing the holding means, the second holding means is provided with a transparent window, and a light source for generating monochromatic light in the vicinity of the transparent window. Then, monochromatic light is incident on the liquid crystal display panel from the light source, and based on the interference fringes generated by the monochromatic light, the first and second
The problem is solved by a method of controlling the cell gap of the liquid crystal display panel by controlling the pressure part of.

According to the second aspect of the present invention, the number of interference fringes is measured by further imaging means for picking up an image of the interference fringes displayed on the liquid crystal display panel and image processing of the image displayed on the liquid crystal display panel. And an automatic adjusting valve for adjusting the pressurizing means and the depressurizing means according to the adjusting signal. And the said subject was solved by automatically controlling the cell gap of a liquid crystal display panel by the automatic adjustment valve.

Further, in the cell gap control device of the present invention, the first holding means is provided with the first pressure section, the second holding means is provided with the second pressure section, and the first and second pressure sections are provided. A conduit connected to the conduit, a regulating valve connected to the conduit, a pressurizing means and a depressurizing means connected to the regulating valve, and a biasing means for biasing the holding means to the first holding means, The second holding means was provided with a transparent window and a light source for making monochromatic light incident on the liquid crystal display panel to generate interference fringes.

According to another aspect of the present invention, the number of interference fringes is measured by further image pickup means for picking up an image of the interference fringes displayed on the liquid crystal display panel and image processing of the image displayed on the liquid crystal display panel. And an automatic adjusting valve for adjusting the pressurizing means and the depressurizing means by the adjusting signal.

[0015]

According to the cell gap control method of the present invention having such a configuration, the first and second light sources emit monochromatic light from the light source to the liquid crystal display panel and the interference fringes are generated on the liquid crystal display panel by the monochromatic light. Since the pressure gap is controlled to control the cell gap of the liquid crystal display panel, the user can directly visually see the variation in the cell gap of the liquid crystal display panel, and Control and adjustment can be performed easily.

According to the second aspect of the present invention, which is intended to be automated, an image of interference fringes is picked up by a CCD camera, the image is image-processed to measure the number of interference fringes, and the number of interference fringes is reduced. Since the automatic adjustment valve is adjusted, the cell gap of the liquid crystal display panel can be automatically controlled and adjusted.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the cell gap control device and the control method thereof according to the present invention will be described below with reference to FIGS. The same parts as those of the conventional liquid crystal display panel are designated by the same reference numerals, and the description thereof will be partially omitted.

Embodiment 1 With reference to FIGS. 1 and 2, a first embodiment of the cell gap control apparatus and the control method thereof according to the present invention will be described. First, the configuration of the cell gap control device of the present invention will be described with reference to FIG. 1A is a configuration diagram showing a first embodiment of a cell gap control device of the present invention, and FIG. 1B is a front view showing a liquid crystal display panel to be controlled.

In FIG. 1A, reference numeral 10 indicates a cell gap control device of the present invention. The cell gap control device 10 of the present invention includes a base 6, a compression coil spring 7 serving as an urging means disposed on the base 6, and a first holding device that is provided with the compression coil spring 7 and holds the liquid crystal display panel 1. Means 8 and second
The holding means 9 of FIG.

The first holding means 8 has a first pressure portion 11
However, the second holding means 9 is provided with the second pressure portion 12, and the first pressure portion 11 and the second pressure portion 12 are provided.
A conduit 13 extends from which a control valve 14 is connected. Further, a pressurizing means 15 and a depressurizing means 16 are connected to the control valve 14. A transparent window 17 is formed in the second holding means 9, and a light source 18 for generating monochromatic light is arranged in the vicinity of the transparent window 17 by a predetermined means.

In FIG. 1B, the liquid crystal display panel 1
Is composed of a counter substrate and a drive substrate as described above, and these two glass substrates are gap-controlled by spacers according to the target gap length. The liquid crystal display panel 1 of the present embodiment has a relatively small area, and the gap between the glass substrates is controlled by dispersing the gap material in the sealing material 19 that adheres the periphery. To do. The liquid crystal display panel 1 is provided with an injection hole 20, and the liquid crystal 5 is injected from the injection hole 20.

The operation of the cell gap control device of the present invention having such a configuration will be described. The user holds the liquid crystal display panel 1 by the first holding means 8 and the second holding means 9 of the cell gap control device 10 of the present invention and operates the operating device (not shown) to operate the cell gap control device of the present invention. The control device 10 is activated to cause the light source 18 to generate monochromatic light.

At this point, the first holding means 8 and the second holding means 8
On the liquid crystal display panel 1 held by the holding means 9, the interference fringes A as shown in FIG. The user visually recognizes the interference fringe A with the eyeball B through the transparent window 17 provided in the second holding means 9 to detect the in-plane variation of the cell gap.

The user detects the in-plane variation of the cell gap of the liquid crystal display panel 1 on the basis of the interference fringes A and operates the operating means to control the adjusting valve 14 to control the first pressure unit. The cell pressure is controlled and adjusted by controlling the air pressures of 11 and the second pressure section 12. That is, the control valve 14 is controlled so that the interference fringes A of the liquid crystal display panel 1 have a desired number of interference fringes, and the first pressure unit 11 and the second pressure unit 11
By controlling the air pressure of the pressure unit 12, the cell gap of the liquid crystal display panel 1 is optimally controlled. Here, the interference fringes are commonly called Newton's rings, and are a series of bright and dark ring zones that appear around the contact points of two glass plates when monochromatic light is applied to them. There are interference fringes caused by interference of light reflected from glass surfaces that are close to each other.

Next, the control method of the cell gap control device of the present invention will be described in detail with reference to FIG. FIG. 2A is an enlarged cross-sectional view showing a cell gap control method in a concave liquid crystal display panel, and FIG. 2B is an enlarged cross-sectional view showing a cell gap control method in a convex liquid crystal display panel.

When a concave liquid crystal display panel is installed in the cell gap control device of the present invention shown in FIG. 2 (a), the pressure regulating valve for controlling the pressure of the first pressure portion 11 and the second pressure portion 12 is adjusted. The suction force C is generated by reducing the pressure by the pressure reducing means through the suction force C, and the liquid crystal display panel 1 is sucked by the suction force C. Then, the liquid crystal 5 attached to the injection hole 20 is drawn into the inside, and the cell gap of the liquid crystal display panel 1 is uniformly controlled. Then, when the desired number of interference fringes is reached, the liquid crystal 5 is wiped, the sealing material 21 is applied by a sealing material applying machine, and the sealing material 21 is UV-cured by the UV exposure device 22. The liquid crystal display panel 1 sealed and controlled to the optimum cell gap is completed.

When a convex liquid crystal display panel is installed in the cell gap control device of the present invention shown in FIG. 2 (b), the control valve for adjusting the pressures of the first pressure portion 11 and the second pressure portion 12 described above. A compressing force D is generated by pressurizing the liquid crystal display panel 1 via the pressurizing means, and the liquid crystal display panel 1 is compressed by the compressing force D. Then, the liquid crystal 5 is ejected from the injection hole 20 and the cell gap of the liquid crystal display panel 1 is uniformly controlled. Then, when the desired number of interference fringes is reached, the liquid crystal 5 is wiped, the sealing material 21 is applied by a sealing material applying machine, and the sealing material 21 is UV-cured by the UV exposure device 22. The liquid crystal display panel 1 that is sealed and controlled to have an optimum cell gap is completed.

Since it is difficult to determine whether the liquid crystal display panel is concave or convex simply by measuring the number of interference fringes, it is necessary to actually determine the shape of the interference fringes first. That is, when the number of interference fringes is measured while performing minute pressurization or depressurization processing by the first pressure unit 11 and the second pressure unit 12, the number of interference fringes changes. Therefore, if the number of interference fringes increases due to pressurization, it is determined to be concave, and if the number of interference fringes decreases due to pressure, it is determined to be convex. Based on the result of this determination, in the case of the concave shape, the processing as shown in FIG. 2A is performed, and in the case of the convex shape, the operation as shown in FIG. 2B is performed.

Embodiment 2 This embodiment is an example of automation instead of the manual control method of the cell gap control device in the first embodiment, which will be described with reference to FIG. Note that the same parts as those of the first embodiment, especially the common parts of the cell gap control device, are duplicated and the description thereof is omitted. FIG. 3 is a block diagram showing a second embodiment of the cell gap control device of the present invention.

In FIG. 3, reference numeral 30 indicates a cell gap control device of the present invention. The cell gap control device 30 of the present invention includes a base 6, a compression coil spring 7 disposed on the base 6, a first holding unit 8 that is attached to the compression coil spring 7, and holds the liquid crystal display panel 1 and a first holding unit 8. 2 holding means 9 and the like. The first pressure means 11 is provided in the first holding means 8,
The second holding means 9 is provided with a second pressure section 12, and an automatic control valve 31 is connected from the first and second pressure sections via a conduit 13 to the automatic control valve 31. The pressurizing means 15 and the depressurizing means 16 are connected. A transparent window 17 is formed on the side surface of the second holding means 9, and a light source 18 for generating monochromatic light is provided outside the transparent window 17.

The cell gap control device 30 of the present invention performs image processing on the CCD camera 32, which is a new image pickup means, and the image picked up by the CCD camera 32, in addition to the components substantially common to those of the first embodiment. The control means 33 is provided to adjust the automatic control valve 31 so that the number of interference fringes is predetermined. The CCD camera 32 and the adjusting means 33 are connected by a cable 32a, and the adjusting means 33 and the automatic adjusting valve 31 are connected by a cable 33a.

The operation of the cell gap control device of the present invention having such a configuration will be described. The user is the first holding means 8 and the second holding means 9 of the cell gap control device 30 of the present invention.
The cell gap control device 30 of the present invention is obtained by holding the liquid crystal display panel 1 and operating an operating device (not shown).
Is activated to generate monochromatic light from the light source 18.

At this point, the first holding means 8 and the second holding means 8
The above-mentioned interference fringes are generated on the liquid crystal display panel 1 held by the holding means 9. The CCD camera 32 images this interference fringe and inputs the video signal to the adjusting means 33 via the cable 32a. The adjusting means 33 digitally processes this video signal and measures the number of interference fringes to generate an adjusting signal, which is output to the automatic adjusting valve 31 via the cable 33a. The automatic adjustment valve 31 receives an adjustment signal to adjust the pressure of the pressurizing means 15 and the pressure reducing means 16, and controls the first pressure part 11 and the second pressure part 12 of the cell gap control device 30 of this embodiment. Control and adjust the cell gap by controlling the air pressure.

Then, when the desired number of interference fringes is reached,
The liquid crystal is wiped, the sealing material is applied by a sealing material applicator or the like in the same manner as in Example 1, and the sealing material is UV-cured and sealed by a UV exposure device to control the optimum cell gap. The display panel 1 is completed. In this way, the cell gap control device 30 of the present embodiment can automatically control and adjust the cell gap of the liquid crystal display panel 1. The description of the subsequent operations will be omitted because they overlap.

The present invention is not limited to the above embodiments, and various embodiments can be adopted. For example, although the TFT active matrix type liquid crystal display panel is illustrated as an example in the above embodiment, the present invention can be applied to a simple matrix type liquid crystal display panel and other display devices using a transparent substrate. Further, in the present embodiment, the example in which the air pressure is used as the pressurizing / depressurizing means is shown, but it may be realized by mechanical means such as a compressor or an expander. Further, it goes without saying that the present invention can be developed into various forms without being limited to the embodiment described above.

[0036]

As described above, according to the cell gap control device and the control method thereof of the present invention, the cell gap of the liquid crystal display device is controlled by the interference fringes. It is possible to reduce the defective cell gap and contribute to the cost reduction of the liquid crystal display device, and to obtain a uniform and high-quality display image. Further, since the method for controlling the cell gap of the present invention is performed after the liquid crystal is injected, it is possible to simplify the management of the cell gap in the process before that, and there is an effect that the manufacturing cost of the liquid crystal display device is reduced.

[Brief description of drawings]

FIG. 1A is a configuration diagram showing a first embodiment of a cell gap control device of the present invention, and FIG. 1B is a front view showing a liquid crystal display panel to be controlled.

FIG. 2A is an enlarged cross-sectional view showing a method of controlling a cell gap in a concave liquid crystal display panel, and FIG.
FIG. 6 is an enlarged cross-sectional view showing a method of controlling a cell gap in a convex liquid crystal display panel.

FIG. 3 is a configuration diagram showing a second embodiment of the cell gap control device of the present invention.

FIG. 4 is a cross-sectional view showing a main part of a liquid crystal display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 2 Counter substrate 3 Drive substrate 4 Spacer 5 Liquid crystal 6 Base 7 Compression coil spring 8 First holding means 9 Second holding means 10, 30 Cell gap control device 11 of the present invention 11 First pressure portion 12 Second pressure part 13 Conduit 14 Control valve 15 Pressurizing means 16 Depressurizing means 17 Transparent window 18 Light source 19 Sealing material 20 Injection hole 21 Sealing material 22 UV exposure device 31 Automatic control valve 32 CCD camera 33 Controlling means A Interference fringe

Claims (4)

[Claims] 1. A method for controlling a cell gap of a liquid crystal display panel filled with liquid crystal, comprising: first and second holding means for holding the liquid crystal display panel; and a first holding means provided in the first holding means. A pressure part, a second pressure part provided in the second holding means, and the first pressure part.
And a conduit connected to the second pressure section, a control valve connected to the conduit, pressurizing means and depressurizing means connected to the control valve, and holding means attached to the first holding means. A biasing means for biasing, a transparent window in the second holding means, and a light source for generating monochromatic light in the vicinity of the transparent window are provided, and the monochromatic light is emitted from the light source to the liquid crystal display panel. Incident,
An interference fringe is generated in the liquid crystal display panel by the monochromatic light, and the cell gap of the liquid crystal display panel is controlled by controlling the first and second pressure portions based on the interference fringe. Cell gap control method. 2. An image pickup unit for picking up an image of the interference fringes displayed on the liquid crystal display panel, and measuring and adjusting the number of the interference fringes by image-processing the image displayed on the liquid crystal display panel. Adjusting means for generating a signal, an automatic adjusting valve for adjusting the pressurizing means and the depressurizing means according to the adjusting signal, and a cell gap of the liquid crystal display panel is automatically controlled by the automatic adjusting valve. The cell gap control method according to claim 1. 3. A cell gap control device for a liquid crystal display panel filled with liquid crystal, comprising first and second holding means for holding the liquid crystal display panel, and a first holding means provided in the first holding means. A pressure part, a second pressure part provided in the second holding means, and the first pressure part.
And a conduit connected to the second pressure section, a control valve connected to the conduit, pressurizing means and depressurizing means connected to the control valve, and the first holding means includes the first The second holding means includes a biasing means for biasing the holding means, a transparent window, and a light source for causing interference fringes by making monochromatic light incident on the liquid crystal display panel. Cell gap control device. 4. An image pickup means for picking up an image of the interference fringes displayed on the liquid crystal display panel, and measuring and adjusting the number of the interference fringes by image-processing the image displayed on the liquid crystal display panel. The cell gap control device according to claim 3, further comprising: an adjusting unit that generates a signal; and an automatic adjusting valve that adjusts the pressurizing unit and the depressurizing unit according to the adjusting signal.