JPH05113571A - Production of display element - Google Patents

Abstract

PURPOSE:To form the spacing between substrates with good accuracy by forming electrodes on the bottom surfaces of substrates constituting a cell and sticking the substrates to each other by using a pressure reduction method. CONSTITUTION:The ruggedness on the surface (bottom surface) in contact with a metallic roll tends to be removed of itself at the time of producing a plate glass sheet (glass substrate). An oriented film is formed on the surface of the glass substrate 2 formed with the transparent electrodes 1 on the bottom surface having the lesser rugged surface. An adhesive 4 for sealing is printed in the position corresponding to the periphery of the display area of the liquid crystal display panel. The electrode surface of the glass substrate 2' formed with the electrode patterns 1' is disposed to face the transparent electrodes 1 of the substrate 2 and glass fiber pieces having a prescribed diameter are scattered as spacers 3 therebetween. The substrates are then superposed on each other. A reduced pressure state is generated in the gap formed between the substrates 2 and 2' and the adhesive 4 is allowed to cure while the reduced pressure state is maintained. A liquid crystal 5 as a display material is thereafter into the gap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a display device in which a display material is filled between two substrates having electrodes.

[0002]

2. Description of the Related Art Among display elements, such as a liquid crystal, electrochromic, or electrophoretic method, in which cells having counter electrodes are formed and the voids thereof are filled with a liquid display material, the space between the counter electrodes is reduced. It is a major factor to determine the quality of the characteristics how to form the gaps evenly, accurately and reproducibly. Further, as the contents of display and the amount of information increase and the power consumption needs to be reduced, the pattern becomes more complicated, larger, and the gap is reduced and evened.

A conventional method for uniformly forming these gaps will be described by taking a liquid crystal display element as an example. First, as shown in FIG. 1, a glass substrate 2 having a transparent electrode 1 formed in a display pattern on its surface is fixed by an adhesive layer 4 formed in a peripheral portion via a spacer 3 having a size corresponding to a required gap, Liquid crystal 5 is injected into the gap as a display material to form a liquid crystal display element.

In this case, the glass substrates 2 and 2'on which the sealant layer (4) made of an adhesive is formed by printing or the like along the periphery of the shape where the liquid crystal 5 is to be injected, the transparent electrodes are provided via the spacers 3. After stacking with the 1 side facing each other,
A display element cell is manufactured by heating the entire surface with pressure applied by a load of about several tens of kg / cm ² to cure the adhesive 4.

[0005]

In such a conventional method, when mass-producing, for example, several dozen cells that have been bonded are stacked, and the adhesive is heated and cured in a thermostatic chamber while applying a weight to the stacked cells. To do. However, in this case, the weight is applied significantly differently on the lower side and the upper side of the stacked cells, the heat is not uniformly applied to each part of the adhesive, and the thickness of the glass substrate of the cells is varied, and so on. Since the pressure is not uniformly applied to the two glass substrates 2 and 2 ', a variation of about ± 1 μm occurs with respect to the gap of 7 to 8 μm between the two glass substrates 2 and 2'. This makes it difficult to obtain a high yield when mass-producing,
If the accuracy of gap variation is required to be about ± 0.5 μm, the yield will be further reduced. In particular, the larger the panel (display element cell) and the higher the gap accuracy required, the greater the tendency for mass production to become difficult.

An object of the present invention is to solve the above-mentioned problems and to provide a method for accurately forming a gap between substrates constituting a cell.

[0007]

A method of manufacturing a display element of the present invention is a method of stacking cells adhered by an adhesive and manufacturing them without applying pressure. It is characterized in that an electrode is formed.

[0008]

According to such a method, the gap is determined by the size (height) of the spacer itself without being influenced by the variation in the thickness of the substrate and the unevenness of the weight applied at the time of pressing.
That is, if the precision of the size of the spacer is selected and used to a sufficient extent, a sufficiently high yield can be obtained even if the gap precision between the substrates is about ± 0.5 μm without causing manufacturing variations in the manufacturing method. ..

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As the spacer used in the practice of the present invention, glass fiber having a constant outer diameter is cut, or a spherical resin material having a carefully selected particle diameter is effective. Further, the method of reducing the pressure is not limited to one, and various methods can be applied. For example, any equipment may be used as long as it has a sealing jig designed so that the peripheral portions of two glass substrates are pressure-bonded via a spacer and the voids thereof are heated and hardened while maintaining a reduced pressure. However, when using a simple device, a cell in which the adhesive is uncured is inserted into a bag in which two heat-resistant resin films (plastic films) are sealed on three sides, and this is depressurized. The heat-resistant resin film in which cells are inserted after the remaining one is sealed by a method such as heat sealing and then the heat corresponding to the curing condition of the adhesive is applied to completely cure the sealing agent layer made of the adhesive 4. Is effective.

When the gap itself is made smaller and the accuracy thereof is increased in view of performance requirements, the surface smoothness of the substrate to be used becomes a problem and it is necessary to select and use it. The smoothness may be increased by polishing or the like, but the manufacturing cost is increased in practical use. Therefore, it is effective to use the glass in consideration of the general tendency of the smoothness caused by the general glass manufacturing method. That is, a soda glass plate having a thickness of about 1.1 mm, which is often used for display elements such as liquid crystal, pulls up the molten soda glass 6 as shown in FIG.
It is manufactured as a flat glass sheet 8 having a constant thickness by pulling the top in the direction of the arrow and cooling. Here, generally, the surface that does not touch the metal roll 7 is called the top surface (T), and the surface that touches it is called the bottom surface (B), and the top surface is likely to have surface irregularities in the pulling direction. However, the bottom surface is metal roll 7
Because of touching, the unevenness in this direction tends to be naturally removed. However, since the gap accuracy has not been required so strictly in the past, a transparent electrode such as In ₂ O ₃ is formed on the top surface of the plate glass sheet 8 (glass substrate) that does not touch the metal roll 7.

In one embodiment of the present invention, contrary to such a conventional method, a transparent electrode is formed on the bottom surface of a glass substrate having a small number of irregularities, and the surface of the two glass substrates is interposed by a spacer. By configuring the cells so that they face each other, it is possible to form a cell gap with higher accuracy.

Next, the present invention will be described with reference to more specific examples, and the effects thereof will be shown in FIG. A transparent electrode 1 having a desired shape made of In ₂ O ₃ is formed on one surface of the substrate, 1.1 mm thick, 300
An alignment film is formed on the surface of the × 300 mm glass substrate 2, and the sealing adhesive 4 left in the injection portion is formed by screen printing at a position corresponding to the periphery of the display area of the liquid crystal display panel. The electrode surfaces of the glass substrate 2'on which the opposing electrode patterns 1'are formed are made to face each other, and glass fiber pieces having a diameter of 8 .mu.m are interspersed as spacers 3 between them so that their positions are aligned and superposed. (See Figure 1).

At this time, the two glass substrates 2 and 2'are bonded by the uncured epoxy adhesive 4 for sealing.

Next, this is first heat-cured using a conventional simple pressing method. After stacking 20 to 30 uncured cells on a smooth plate (not shown),
A weight (not shown) of 00 kg is placed and the product is left standing in a dryer (not shown) at a heating temperature of 120 ° C. for 90 minutes to cure the epoxy adhesive layer (4). As a result of measuring variations in the gap accuracy of the cells obtained by such a conventional simple pressurizing method for 10 lots, the yield of 8 μm ± 1.0 μm is 58.5%, and at ± 0.5 μm, 33. 0%,
At ± 0.3 μm, it was further reduced to 11.2% (see FIG. 3).

Next, the cells, which are aligned and superposed in the same manner, are heated and cured by the method of the present invention. First, each cell was inserted into a bag-shaped heat-resistant film (plastic film bag) in which three sides were sealed, and the pressure was reduced to 10 ^-2 mmHg using a vacuum packaging machine (not shown). The remaining one is sealed by heat sealing to make a vacuum sealed state.
Next, the cells are taken out from the vacuum packaging machine together with the plastic film bags, and 20 to 30 sheets are stacked in a dryer. Then, depending on the curing condition of the epoxy seal adhesive, 12
After curing by heating at 0 ° C., the bag is cut and each cell is taken out. The variation in the gap accuracy of the cells thus obtained is 8 μm ± 1.0 μm, and the yield is 99.4%.
89.5% at ± 0.5 μm and 49.% at ± 0.3 μm.
This is 9%, and the effect is remarkable as compared with the conventional pressurizing method (see FIG. 3).

In these examples, general products in which a transparent electrode is provided on the top surface of the above-mentioned glass substrate are used. However, the yield at ± 0.3 μm is still insufficient. Therefore, in order to improve this point, conversely, when a transparent electrode is formed on the bottom surface of the glass substrate and the decompression method of the present invention is used, ± 0.
Yield of 5 μm is 95.3%, 85% even at ± 0.3 μm.
It improved to 5% (see FIG. 3).

The results of the embodiment are summarized in FIG. 3 in order to clarify these effects. That is, the effect becomes more remarkable as the requirement of the gap precision becomes stricter to ± 1.0 μm and ± 0.5 μm by the decompression method of the present invention. Further ± 0.3μ
When the demand becomes more severe like m, the sledge of the glass itself,
Alternatively, the effect of unevenness becomes large, and the effect of the mere construction method is still insufficient, and further effects can be obtained by combining this with selective use of glass.

[0018]

As described above, in order to improve the display performance of the display element cell in which the display material is enclosed in the gap between the two glass substrates with transparent electrodes facing each other represented by the liquid crystal, the gap accuracy is improved. When it is required even more remarkably, the present invention can be mass-produced at low cost by a simple construction method in which an electrode is formed on the bottom surface of the substrate, and the practical effect is great. Then, by selectively combining and applying the conditions of the present invention in accordance with the accuracy required in relation to the display characteristics, a great effect is brought about in improving the accuracy of the display cell and improving the manufacturing yield.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a display panel for explaining a conventional method of manufacturing a display element.

FIG. 2 is a diagram showing a manufacturing process of a glass plate used in the manufacturing method of the present invention.

FIG. 3 is a diagram for demonstrating the effect of the manufacturing method of the present invention.

[Explanation of symbols]

 6 Molten glass 7 Feed roll 8 Flat glass sheet

Claims (1)

[Claims] 1. An adhesive layer is provided on the periphery of two substrates having electrodes, the substrates are stacked via a spacer having a certain size so that the electrode surfaces face each other, and the adhesive layers are formed between the substrates. A method of manufacturing a display element, characterized in that the internal voids are depressurized, the adhesive is cured while the depressurized state is maintained, and then a display material is injected into the internal voids. A method of manufacturing a display element, comprising forming electrodes on a bottom surface, press-bonding the two substrates via the spacers so that the electrode sides face each other, and injecting a display material into the internal voids.