JPH0616137B2 - Display element manufacturing method - Google Patents

Description

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.

Structure of conventional example and its problems Among the display elements, such as liquid crystal, electrochromic, and electrophoretic method, a cell having a counter electrode is formed, and its void is filled with a liquid display material. How to uniformly and accurately and reproducibly form the gap for increasing the counter electrode is a major factor in determining the quality of the characteristic. Furthermore, the more the display content and the amount of information increase, and the more power saving is required, the more complicated the pattern becomes.
Larger size, reduction of gap and equalization are required more severely.

A conventional method of 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. Then, a liquid crystal 5 is injected into the gap as a display material to form a liquid crystal display element.

In this case, the glass substrate 2, 2 ′ on which the sealant layer (4) made of an adhesive is formed by printing or the like along the periphery of the shape in which the liquid crystal 5 should be injected, the transparent electrode 1 through the spacer 3.
After stacking with the sides facing each other, dozens of kg /
A display element cell is manufactured by heating the adhesive 4 while applying pressure with a load of about cm ² to cure the adhesive 4.

In such a conventional method, for mass production, several tens of bonded cells are stacked, and the adhesive is heated and cured in a thermostatic chamber while applying a weight to the stacked cells. However, in this way, the way the weight is applied is significantly different on the lower side and the upper side of the stacked cells, and the heat is not uniformly applied to each part of the adhesive,
Further, the cells are not uniformly pressed due to variations in the thickness of the glass substrate of the cell, and the two glass substrates 2,
A variation of about ± 1 μm occurs for a cap of 7 to 8 μm between 2 ′. In this case, it is difficult to obtain a high yield in mass production, and the gap variation accuracy is ± 0.
If the required amount is about 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.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a method for accurately forming a gap between substrates constituting a cell.

Configuration of the invention The method for producing the display element of the present invention is a method for producing the laminated layers laminated with an adhesive without applying pressure, and two substrates crimped via a spacer in a plastic film bag. It is inserted and the pressure is reduced including the outer peripheral part of the plastic film bag, and the inside of the plastic film bag is hermetically sealed while the pressure is reduced, and then the substrate is inserted into the plastic film bag and heated and cured under the curing conditions of the adhesive. . According to such a method, the gap is determined by the size (height) of the spacer itself without being affected by variations in the thickness of the substrate and unevenness in weighting during pressurization. That is, if the size accuracy of the spacer is sufficiently selected and used, the gap accuracy between the substrates can be kept within ±
It is possible to request about 0.5 μm and obtain a sufficiently high yield.

Description of 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 such that the peripheral portions of two glass substrates are pressure-bonded via a spacer and the voids are kept under reduced pressure so that they can be heat-cured. However, when using a simple device,
3 of 2 heat-resistant resin film (plastic film)
The uncured cell is inserted into the bag that seals the other side, and one that remains in a depressurized state is sealed with a method such as heat sealing and then corresponds to the curing condition of the adhesive. A method is effective in which heat is applied to completely cure the sealant layer made of the adhesive 4 and then the heat-resistant resin film in which the cells are inserted is removed.

When the gap itself is made smaller and the accuracy thereof is increased due to 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, 1.1 mm that is often used for display devices such as liquid crystals.
A soda glass plate having a certain thickness is manufactured as a plate glass sheet 8 having a certain thickness by pulling up the molten soda glass 6 as shown in FIG. 2 and sequentially pulling it on the metal roll 7 in the direction of the arrow to cool it. Is. Here, generally, the surface not touching the metal roll 7 is called the top surface (T), and the surface touching it is called the bottom surface (B), and the top surface is likely to have surface irregularities in the pulling direction. However, since the bottom surface touches the metal roll 7, the unevenness in this direction tends to be removed naturally.
However, since the gap precision 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 an 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 uneven surfaces, and the surfaces of two glass substrates are opposed to each other by using a spacer. By at least configuring the cell, it is possible to form the cell gap with higher accuracy.

Next, the present invention will be described more specifically by way of examples, and the effects thereof will be shown in FIG.

An alignment film is formed on the surface of a glass substrate 2 having a thickness of 1.1 mm and a size of 300 × 300 mm, and a transparent electrode 1 of In ₂ O _{3 having} a desired shape is formed on one surface of the glass substrate 2. The sealing adhesive 4 left on the part is formed by screen printing. Opposing electrode pattern 1 '
By making the electrode surfaces of the glass substrate 2'formed with
In the meantime, glass fiber pieces having a diameter of 8 μm are interspersed with each other in a state of being scattered as spacers 3 (see FIG. 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 by using a conventional simple pressing method. After stacking 20 to 30 uncured cells on a smooth plate (not shown), a 1500 kg weight (not shown) is placed on it and a dryer (not shown) at a heating temperature of 120 ° C. Then, the epoxy adhesive layer (4) is allowed to stand for 90 minutes to cure. As a result of measuring variations in the gap accuracy of the cell obtained by such a conventional simple pressurizing method for 10 lots, the step count of 8 μm ± 1.0 μm is 58.5.
%, 33.0% at ± 0.5 μm, ± 0.3 μm
Then, it further decreased to 11.2% (see FIG. 3).

This time, the cells, which have been aligned and superposed in the same manner, are heated and cured by the method of the present invention. First, insert cells one by one into a bag-shaped heat-resistant film (plastic film bag) with three sides sealed, and reduce the pressure to 10 ^-2 / mmHg using a vacuum packaging machine (not shown). Then, seal the remaining one by heat sealing and put it in a vacuum sealed state.Next, take out the cell together with the plastic film bag from the vacuum packaging machine,
20 to 30 sheets are stacked in a dryer. Then, after heating and curing at 120 ° C. according to the curing condition of the epoxy sealing adhesive, the bag is cut and the cells are taken out. The variation of the cell gap accuracy thus obtained is 8 μm.
The step count becomes ± 1.0 μm, 99.4%, ± 0.5 μm
Is 89.5%, and ± 0.3 μm is 49.9%, which is more remarkable than the conventional pressing method (see FIG. 3).

These examples use general products in which a transparent electrode is provided on the top surface of the glass substrate. But ± 0.3
Since the grading at the time of μm is still insufficient, 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, it is ± 0.5 μm. The yield was improved to 95.3% and to 85.5% at ± 0.3 μm (see FIG. 3).

In order to clarify these effects, the results of the third embodiment will be described below.
Summarized in the figure. That is, the effect becomes more remarkable as the demand for the gap accuracy becomes ± 1.0 μm and ± 0.5 μm by the decompression method in the present invention. Furthermore, if the requirement becomes even more rigorous, such as ± 0.3 μm, the effect of warpage or unevenness of the glass itself becomes large, and the effect of the mere construction method is still insufficient. By combining this with selective use of glass, The effect is obtained. Further, not only the inside of the plastic film bag as in the present embodiment, but also by depressurizing the outer peripheral portion thereof, no pressure difference occurs inside and outside the bag,
Therefore, the bag does not wrinkle and can be mass-produced more uniformly.

Although the thermosetting resin is used as the adhesive in the present embodiment, it is obvious that the same effect can be obtained by using, for example, an ultraviolet curable resin.

EFFECTS OF THE INVENTION As described above, in order to improve the display performance of a display element cell in which a display material is sealed in a gap between two glass substrates with transparent electrodes facing each other, which is represented by a liquid crystal, the gap precision is more remarkable. When required, the present invention can be mass-produced at a low cost by an extremely simple construction method and has a large practical effect. 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.

Further, the present invention does not require a special jig, a large-scale facility, a device, and a complicated work, and simply uses a plastic film bag and a vacuum packaging machine to vacuum-pack two electrode substrates and use them as a dryer. It only needs to be put in and the resin to be cured, and the work is easy and inexpensive, and it is possible to apply a uniform force to the substrate when the adhesive is cured.

[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 substrate used in the manufacturing method of the present invention, and FIG. 3 is a manufacturing method of the present invention. It is a figure for demonstrating the effect of a method. 6 ... Molten glass, 7 ... Feed roll, 8 ... Flat glass sheet.

Claims (3)

[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 adhesive layers face each other, and the adhesive layers are formed between the substrates. A method of manufacturing a display element in which the internal voids are depressurized, the adhesive is cured while maintaining the depressurized state, and then a display material is injected into the internal voids, which is pressure-bonded through the spacers. Two substrates are inserted into a plastic film bag, and the plastic film bag is placed in a decompression container together with the outer peripheral portion of the plastic film bag to decompress, and the plastic film bag is completely sealed under decompression, and then the decompression container. And then heat-curing under the curing conditions of the adhesive, then take out the substrate from the plastic film bag and inject the display material into the internal voids. A method of manufacturing a display element, comprising: 2. The method of manufacturing a display element according to claim 1, wherein a glass substrate with a transparent electrode is used as the substrate and the electrode, and a liquid crystal material is used as the display material. 3. An adhesive layer is provided on the periphery of two glass substrates having electrodes, and the glass substrates are superposed on each other via a spacer having a certain size so that the adhesive layers face each other.
A method of manufacturing a display element, wherein an internal void formed between the glass substrates is in a reduced pressure state, the adhesive is cured while maintaining the reduced pressure state, and then a display material is injected into the internal void. An electrode is formed on the bottom surface of the glass substrate, the two glass substrates are pressure-bonded via the spacer so that the electrode sides face each other, the glass substrate is inserted into a plastic film bag, and the plastic film bag is decompressed together. Put in a container, decompress including the outer peripheral portion of this plastic film bag, completely seal the plastic film bag under reduced pressure, then take out from the decompression container, and further heat cure under the curing conditions of the adhesive, then the plastic A method for manufacturing a display device, characterized in that the glass substrate is taken out from a film bag and a display material is injected into an internal void thereof. .