JPH05165041A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To reduce various failures due to electrostatic charge and enhance the yield by specifying the resistance value between adjoining electrodes on base boards. CONSTITUTION:The resistance value between adjoining electrodes 6, 7 on base boards 2, 3 is made over 50 times as great as the resistance value between the two ends of electrodes 6, 7 and ranging between 100kohm and 10Mohm. The electrostatic charge amount of static electricity generated during handling or in the manufacturing process is several kvolts thru several tens of kvolts, and the generated electric charges are released easily as long as the bearing resistant body has no more than several Mohms. If the resistance value between adjoining electrodes is made below 10Mohms, therefore, the electric amounts are put in equilibrium with each other even in the event of generation of static electricity, and there is no risk of deterioration of a liquid crystal compound 10 and orientation films 8, 9. The drive voltage may remain as low as several volts by effective value and several tens of volts by the momentary peak value, and as long as the resistance between adjoining electrodes is over 100kohm and is 50 times or more of the resistance value between the two electrode ends, electric charges do not transfer to other electrode even though drive voltage is impressed, which presents a fine grade of displaying.

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, and more particularly to a simple matrix type or active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements have come into the market as a display for televisions, word processors, personal computers, etc., taking advantage of their advantages such as light weight and low power consumption. The demand for higher display quality is increasing.

A liquid crystal display element which is generally used at present has a structure in which a liquid crystal composition is sandwiched between two glass substrates having electrodes. For example, in a simple matrix drive dot matrix liquid crystal display, a Y substrate having scan line electrodes patterned in the horizontal (Y) direction in a strip shape and an X substrate having signal line electrodes patterned in the vertical (X) direction in a strip shape And the scanning line electrode and the signal line electrode are arranged so as to be substantially orthogonal to each other, and the liquid crystal composition is sandwiched therebetween. A nematic liquid crystal is used as the liquid crystal composition, and if necessary, it is placed between two polarizing plates. In an active matrix drive liquid crystal display element, for example, amorphous silicon (a-
Si) has a thin film transistor (TFT) as a semiconductor layer, a display electrode and a signal electrode connected to the TFT, a TFT array substrate on which a gate electrode is formed, and a counter electrode provided opposite to the TFT array substrate. The liquid crystal composition is sandwiched between the counter substrate and the counter substrate.

When manufacturing a liquid crystal display device having these structures, various display defects often occur due to static electricity. That is, during the substrate cleaning during the manufacturing process, the alignment treatment (for example, rubbing treatment), the assembly, the sticking of the polarizing plate, and during other various processes or during the transfer of the substrate between these processes, or after the liquid crystal display element is completed, the driving is performed. Static electricity is generated due to various factors in the process of making a connection IC into a connection module, which locally deteriorates the liquid crystal composition, the alignment film, and the like in the display portion at a specific location, resulting in dot-like or uneven display on the surface. And an abnormal voltage is applied to the TFT element to cause display unevenness due to deterioration of the characteristics of the TFT element, which is a very serious problem in practical use.

On the other hand, a countermeasure called a short ring method has been proposed in which the electrodes on the substrate are short-circuited in advance, the manufacturing process is performed, and the electrodes are separated later.

FIG. 7 shows an example of a short ring method in a simple matrix driving dot matrix liquid crystal display.
The Y electrode group 61 patterned on the Y substrate 60 in the Y direction in a strip shape is short-circuited by a short ring 62.
Further, the X electrode group 71 patterned in a strip shape in the X direction on the X substrate 70 is short-circuited by the short ring 72. In this way, the liquid crystal display element is manufactured with the electrodes short-circuited, and the short ring portions 62 and 72 are separated later.

FIG. 8 shows an example of the short ring method in the case of a TFT driving active matrix liquid crystal display element. The signal electrode 81 and the gate electrode 82 on the TFT array substrate 80 are short-circuited by the short ring portion 83.
In this way, the liquid crystal display element is manufactured with the electrodes short-circuited, and the short ring portion 83 is later cut off.

[0008]

However, the actual situation is that the display defects due to static electricity cannot be completely solved in practical use only by such countermeasures by the short ring method. That is, after the liquid crystal display element is completed, the driving IC
Since the short ring is cut off until the process of converting the above into a connection module, various defects due to static electricity due to various factors actually occur during this period.

The present invention is intended to solve the above problems, and an object of the present invention is to reduce various defects due to static electricity to the extent that there is no practical problem, and to provide a liquid crystal display device having a good yield and therefore a low cost. ..

[0010]

A liquid crystal display element of the present invention is a liquid crystal display element in which at least one substrate has a liquid crystal composition sandwiched between two substrates having a plurality of electrodes, and the two substrates are adjacent to each other. The resistance value between the electrodes is 50 times or more the resistance value between both ends of the electrode and is 100 kilohms (KΩ).
To 10 megohm (MΩ) range.

The resistance portion between adjacent electrodes may be distributed along the electrode wire or may be connected at a specific position.

[0012]

The amount of static electricity generated during the manufacturing process or handling of the liquid crystal display element is several kilovolts to several tens kilovolts. The generated charges are easily diffused on the resistor of about several mega ohms. Therefore, by setting the resistance value between adjacent electrodes on the substrate of the liquid crystal display element to 10 meg or less, even if static electricity is generated during the manufacturing process or handling, the electrodes on the substrate are electrically charged with each other. Is balanced, and a liquid crystal display device in which the liquid crystal composition, the alignment film, the active device and the like are not deteriorated by static electricity can be obtained.

Further, the driving voltage of the liquid crystal display element is as low as several volts as an effective value and as low as several tens of volts even at an instantaneous peak value. According to the experiments by the inventors, the resistance between adjacent electrodes is 100.
The resistance value between the electrodes is preferably 5 kΩ or more and more preferably 5
It is known that if the driving voltage is 0 times or more, even if a driving voltage is applied to the electrodes, good display quality can be obtained without electric charges being transferred to other electrodes.

Therefore, the resistance value between the adjacent electrodes on the substrate is 50 times or more the resistance value between both ends of the electrodes and 10 or more.
Within the range of 0 kilohm to 10 megohm, the liquid crystal composition, the alignment film, the active element and the like are not deteriorated by static electricity, and a liquid crystal display element with good display quality can be obtained.

It is more effective to use the above-mentioned short ring method together with the present invention.

[0016]

【Example】

(Example 1) FIG. 1 is a schematic sectional view of a liquid crystal display element of an example according to the present invention, and FIG. 2 is a schematic plan view. Two substrates 2 and 3 made of transparent glass are arranged so as to face each other, and underlying films 4 and 5 are formed on the surfaces of the substrates 2 and 3 respectively to prevent the elution of impurities from the glass substrates. Strip-shaped transparent electrodes 6 and 7 are formed on the surfaces of the substrates 2 and 3 on which the base films 4 and 5 are formed, and, for example, electrodes are formed on the surfaces of the substrates 2 and 3 on which the transparent electrodes 6 and 7 are formed. Alignment films 8 and 9 that have been rubbed in a certain direction at an angle A with respect to
And the liquid crystal composition 10 is sandwiched between the substrates 2 and 3 in contact with the alignment films 8 and 9 to form the liquid crystal display element 1. In addition, 11 is a gap material and 12 is an adhesive agent for bonding the substrates 2 and 3.

The liquid crystal display element 1 was manufactured as follows.

First, a high resistance made of a silicon-excessive silicon oxide film having a surface resistance of about 10 GΩ / cm ² after being formed as base films 4 and 5 on the surfaces of glass substrates 2 and 3 having an outer shape of 200 mm × 200 mm. A film is formed, and further, an ITO (indium tin oxide) film having a surface resistance of 30 Ω / cm ² is formed on the high resistance films 4 and 5, and the ITO film is etched to have a width of 0.67 mm in the central portion. Bitch 0.70mm, length 150mm 2
00 strip-shaped transparent electrodes 6 and 7 were formed. Then the electrode 6,
After forming a polyimide thin film on the surfaces of the substrates 2 and 3 on which 7 was formed, rubbing treatment was performed to form alignment films 8 and 9.
At this time, the polyimide thin film is formed in a region of 147 mm × 147 mm excluding 6.5 mm on one end side of the strip electrodes 6 and 7, and the rubbing direction is A = 120 for the strip electrodes 6 and 7 on the substrate 6.
For the substrate 7, A = 30 degrees. After that, plastic beads having a particle size of 7 μm were uniformly dispersed as the gap material 11 on the surface of the alignment film 8 of the substrate 2. Further, along the periphery of the alignment film 9, an epoxy adhesive was printed as the adhesive 12 on the surface of the substrate 3 except for the injection port (not shown). Next, the substrates 2 and 3 were arranged such that the alignment films 8 and 9 faced each other and the rubbing directions were 240 degrees, and the substrates were heated and the adhesive was cured to bond the substrates 2 and 3. Next, the bonded substrate 2,
After scribing and breaking 3 into a predetermined shape, 0.7 wt% of S-811 (both manufactured by E. Merck Co., Ltd.) was added to ZLI-2293 as a nematic liquid crystal composition 10 through an injection port by an ordinary method. After injection, the injection port was sealed with an ultraviolet curable resin after this, and a liquid crystal display element 1 was produced.

The resistance between both electrodes of one electrode of the liquid crystal display element 1 thus manufactured and the resistance between the adjacent electrode terminals were measured, and found to be 6.7 KΩ and 667 KΩ, respectively.
Met. Further, when connected to a drive circuit and turned on, there was no short circuit between adjacent electrode terminals, and there was no deterioration of the alignment film and the liquid crystal composition, resulting in a uniform and high-quality display.

Example 2 In Example 1, ITO was used.
At the time of etching the film, the length of the plurality of strip-shaped transparent electrodes 6 and 7 on each substrate is set to 153 mm, and the transparent electrodes 6 and 7 are connected with the end portion of the portion where the polyimide thin film is not formed with a width of 1 mm. Was formed while leaving the ITO film. Then, after the liquid crystal composition 10 is injected and sealed, the strip-shaped transparent electrodes 6 and 7 are formed.
The liquid crystal display element 1 was produced by cutting off the unetched portion of the ITO film which was connected at the end portion.

The resistance between both electrodes of one electrode of the liquid crystal display element 1 thus manufactured and the resistance between adjacent electrode terminals were measured, and found to be 6.8 KΩ and 667 KΩ, respectively.
Met. Further, when connected to a drive circuit and turned on, there was no short circuit between adjacent electrode terminals, and there was no deterioration of the alignment film and the liquid crystal composition, resulting in a uniform and high-quality display.

(Embodiment 3) In Embodiment 1, the surface resistance of one substrate 3 is set to 1 GΩ / cm ² , the scanning line electrode 25 as shown in FIG. 3 and MIM which is a two-terminal active element.
(Metal-Insulator-Metal) In place of the active element substrate 23 having the pixel electrode 22 connected through the element 21,
A liquid crystal display element 1 was produced.

The resistance between one scanning line electrode terminal and the resistance between adjacent scanning line electrodes of the liquid crystal display element 1 thus manufactured were measured and found to be 4.3 KΩ and 4.4 MΩ, respectively. .. Further, when connected to a drive circuit and turned on, there was no destruction or deterioration of the MIM element due to static electricity, and the display was uniform and of high quality.

(Example 4) In Example 2, as shown in FIG. 4, the base films 4 and 5 were SiO ₂ insulating films, and the films were formed between the band-shaped transparent electrodes 6 and 7 and the alignment films 8 and 9. Solution ELCOM = CT-1 in which a highly resistive film is formed after formation
004 (manufactured by Catalysts & Chemicals Industry Co., Ltd.) was spin-coated and baked in air at 300 ° C. for 30 minutes to form high resistance coatings 41 and 51, and a liquid crystal display element 1 was manufactured.

The resistance between both electrodes of one electrode of the liquid crystal display element 1 thus manufactured and the resistance between adjacent electrode terminals were measured, and found to be 6.8 KΩ and 472 KΩ, respectively.
Met. Also, when connected to the drive circuit and turned on,
It was a uniform and high-quality display without causing a short circuit between adjacent electrode terminals and without deterioration of the alignment film and the liquid crystal composition.

(Example 5) In Example 2, the underlying films 4 and 5 were formed of an insulating film of SiO ₂ , and after the liquid crystal composition 10 was injected and sealed, the exposed outside of the seal portion of the electrode terminal portion, for example, 12a. A high resistance film is formed by applying a stat coat (manufactured by Charles Walter Co., USA) with a width of 2 mm between the electrodes adjacent to the partial electrode 6 (the same applies to the electrode 7), and thereafter, a transparent strip The unetched portion of the ITO film connecting the electrodes 6 and 7 at the terminal end was cut off to prepare a liquid crystal display element 1.

The resistance between both electrodes of one electrode of the liquid crystal display element 1 thus manufactured and the resistance between the adjacent electrode terminals were measured, and found to be 6.8 KΩ and 8.7 MΩ, respectively.
Met. Also, when connected to the drive circuit and turned on,
It was a uniform and high-quality display without causing a short circuit between adjacent electrode terminals and without deterioration of the alignment film and the liquid crystal composition.

(Embodiment 6) Another embodiment of the present invention will be described with reference to FIGS. As shown in the figure, a pixel electrode 31, a thin film transistor (TFT) 32 using amorphous Si on a substrate 30 on which a high resistance film 37 is formed,
The active element substrate 30 having the signal line electrodes 33 and the scanning line electrodes 34 with a total of 10,000 pixels in the vertical and horizontal directions and a total of 10,000 pixels was manufactured by a normal process. Next, after forming a polyimide thin film on the surface of the active element substrate 30, a rubbing process was performed to form an alignment film 8. On the other hand, an ITO film was formed as a transparent electrode 36 on the counter substrate 35, a polyimide thin film was formed thereon, and then a rubbing treatment was performed to form an alignment film 9. Thereafter, the substrates 30 and 35 were bonded together in the same manner as in Example 1 so that the rubbing directions were 90 degrees. Next, as the nematic liquid crystal composition 10, ZLI-1565 (manufactured by E-Merck Co., Ltd.) to which 0.1% by weight of S-811 was added is injected.
A liquid crystal display element 1 was produced by sealing the inlet.

When the liquid crystal display element 1 thus produced was connected to a drive circuit and turned on, TF due to static electricity was detected.
There was no destruction or deterioration of T, and the display was uniform and of high quality as in Example 1.

[0030]

According to the present invention, it is possible to obtain a liquid crystal display element which does not affect the display quality even if static electricity is generated in manufacturing or handling.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal display element of one embodiment according to the present invention.

2 is a schematic plan view of the embodiment shown in FIG.

FIG. 3 is a schematic plan view illustrating an MIM element substrate used in another embodiment of the present invention.

FIG. 4 is a schematic sectional view illustrating another embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a liquid crystal display device of another embodiment according to the present invention.

6 is a schematic plan view of the active element substrate of FIG.

FIG. 7 is a plan view of a substrate for explaining the manufacture of the liquid crystal display element by the conventional short ring method.

FIG. 8 is a plan view of a substrate for explaining the manufacture of another liquid crystal display element by the conventional short ring method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element 2, 3 ... Substrate 4, 5 ... Base film 6, 7 ... Strip transparent electrode 8.9 ... Alignment film 10 ... Liquid crystal composition 11 ... Gap material 12 ... Adhesive agent 21 ... MIM element 22 ... Pixel electrode 23 ... Active element substrate 25 ... Scan line electrode 30 ... Active element substrate 31 ... Pixel electrode 32 ... TFT element 33 ... Signal line electrode 34 ... Scan line electrode 35 ... Counter substrate 36 ... Transparent electrodes 41, 51 ... High resistance coating

Claims (1)

[Claims] 1. A liquid crystal display device comprising a liquid crystal composition sandwiched between two substrates, at least one of which has a plurality of electrodes, wherein the resistance value between adjacent electrodes on the substrate is 50 times more than the resistance between both ends and 10
A liquid crystal display device characterized in that it is in the range of 0 kilo ohms to 10 mega ohms.