JPS6237765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a liquid crystal display element, and in particular, a method for manufacturing a liquid crystal display element, in which a lead-out electrode of a liquid crystal display element consisting of a pair of front and back electrode plates is concentrated on one of the electrode plates. Electrical transfer (hereinafter referred to as transfer) carried out for placement
It is related to.

Figures 1, 2, and 3 show the transfer structure of a conventional liquid crystal display element. In the figures, 1 is a front electrode plate that constitutes the liquid crystal display element, and 2 is a back electrode plate. , 3 is a front display electrode, 4 is a back display electrode, 5 is a front transfer electrode, 6 is a back transfer lead-out electrode, 7 is a liquid crystal, 8 is a peripheral sealing material, and 9 is a transfer material.

Next, transfer of a liquid crystal display element according to the prior art will be explained. In general, in a liquid crystal display element composed of a pair of front and back electrode plates, transfer is performed inside the liquid crystal display element in order to concentrate the readout electrodes of the display electrodes on one electrode plate. . Driving of liquid crystal display elements is often carried out by dynamic driving or static driving, but the required number of transfers as described above is
For example, dynamic drive requires a number of transfers corresponding to the reciprocal of the duty of the drive pulse waveform, and static drive generally requires a number of transfers corresponding to the number of display functions. Recently, in particular, liquid crystal display elements have become more multi-functional and high-performance.
As reliability becomes higher, the required number of transfers increases, and demands for higher performance and higher reliability of transfer conduction are particularly increasing. The details will be explained below with reference to FIGS. 1 to 3, taking as an example the case where the lead-out on the front electrode plate side is transferred to the opposite back electrode plate side.

Here, the front electrode plate 1 has, for example, a display electrode 3 made of a transparent conductive film, a transfer electrode 5, etc. formed thereon, and after the liquid crystal is aligned, a transfer material 9 is formed on the transfer electrode 5. For example, after printing the conductive silver paste, so that the transfer material 9 is in a predetermined hardened state,
Cure is being carried out. Further, the back electrode plate 2 disposed opposite to this is formed with display electrodes 4 made of a transparent conductive film, transfer lead-out electrodes 6, etc., and after the liquid crystal is aligned, this electrode plate is formed. A peripheral sealing material 8 is printed over the entire circumference of the surface of the electrode plate 2 to maintain a constant gap between the two electrode plates 1 and 2, as well as to isolate the liquid crystal 7 injected inside from the outside air and keep it airtight. , preliminary curing has been performed and the curing state has been adjusted to a predetermined value.

Both the electrode plates 1 and 2 adjusted to the above-described state are stacked so that the display electrodes 3 and 4 and the transfer electrodes 5 and 6 face each other, and then they are heat-pressed and bonded with a predetermined gap. A hollow cell of a liquid crystal display element is formed, a liquid crystal 7 is injected into the hollow cell, and the liquid crystal 7 is sealed, thereby completing a liquid crystal display element.

Since the conventional liquid crystal display element is constructed as described above, in order to obtain good transfer conduction, first, the transfer material 9 penetrates the layer of the peripheral sealing material 8, and the opposing transfer lead-out electrode After contacting (adhering) 6, this contact (adhering)
It is necessary to maintain the stable state mainly by the adhesive force of the peripheral sealing material 8. Therefore, in the conventional liquid crystal display element, due to the transfer conduction mechanism, firstly, the hardening state of the transfer material 9 and the peripheral sealing material 8 are controlled by controlling the hardening state of the transfer material 9 and the peripheral sealing material 8 before the two electrode plates 1 and 2 are overlapped. This method is extremely difficult to manufacture, as it involves not only transfer conduction, but also the aforementioned problems of controlling the appropriate gap between the hollow cells, controlling the gap distribution, and controlling the shape of the peripheral sealing material 8. In addition, conditions such as temperature and time of heat compression bonding performed after stacking,
The correlation with transfer disconnection defects is as shown in Figure 4. In the figure, curves a, b, and c are measured at different frequencies when the heat-pressing time is 10 minutes, 5 minutes, and 10 minutes, respectively. 2KHz, 32Hz and 32
Shows the results evaluated in Hz. As is clear from Figure 4, there are many drawbacks such as the extremely narrow temperature range for proper heat-press bonding, the need for long-time heat-press bonding, and lack of reproducibility. In most cases, poor contact as shown in FIG. 2 or disconnection as shown in FIG. 3 occur frequently. Furthermore, the results of evaluating the conduction performance of the transfer by this method at a relatively high frequency (2 KHz) show that the frequency dependence is large, as shown by curve a in FIG. 4, and the frequency characteristics are extremely poor. This poor frequency characteristic can be easily inferred from the equivalent circuit of a liquid crystal display element showing defective transfer conduction shown in FIG. 5, and is caused by the contact resistance of the transfer portion.

As explained above, according to the conventional technology, it is extremely difficult to control the proper curing state of the transfer material, peripheral sealing material, etc. before the two electrode plates are stacked together.
The correct temperature range of the heat-compression bonding that is carried out after this is extremely narrow, requiring long-time heat-compression bonding, and lacks reproducibility.In addition, liquid crystal display elements using this method are prone to poor contact and disconnection of the transfer wire. There were many drawbacks such as poor manufacturing yield, poor frequency characteristics, and lack of reliability.

This invention was made to eliminate the drawbacks of the conventional devices as described above, and provides a liquid crystal display element that eliminates the drawbacks of the conventional devices by incorporating a material having a spacer effect into the transfer material. The purpose of this invention is to provide a method for manufacturing.

Next, the invention will be explained. FIG. 6 is a sectional view showing a liquid crystal display element according to an embodiment of the present invention. In the figure, 10 indicates a spacer material mixed in the transfer material 9, and other symbols indicate the first
Since it is the same as the conventional device shown in FIGS. 3 to 3, the explanation will be omitted.

Hereinafter, one embodiment of the transfer according to the present invention will be described in detail with reference to FIG. 6, taking as an example the case where the lead-out of the front electrode plate is transferred to the opposite back electrode plate.

The front electrode plate 1 is used, for example, as a transfer material to be printed on the transfer electrode 5 after the display electrode 3, transfer electrode 5, etc. made of a transparent conductive film are formed, and the liquid crystal is aligned. ,
For example, conductive silver paste 9 may be coated with spacer material 10 corresponding to the gap between the hollow cells.
After printing the transfer material 9, which is mixed with about 5% (by weight) of alumina fine powder with a particle size of 10 microns, it is cured to a predetermined state.
Cure is carried out. Further, on the back electrode plate 2 arranged opposite to this, there are, for example, a display electrode 4 made of a transparent conductive film, and a transfer lead-out electrode 6.
etc. are formed and the liquid crystal is aligned,
A peripheral sealing material 8 is provided over the entire circumference of the surface of the electrode plate 2 to maintain a constant gap between the two electrode plates 1 and 2, to isolate the liquid crystal 7 injected inside from the outside air, and to maintain airtightness. It has been printed, pre-cured, and adjusted to a predetermined curing state. Both electrode plates 1 and 2 adjusted to the state explained above,
Each display electrode 3 and 4, transfer electrode 5 and 6
The liquid crystal display elements are placed on top of each other so that they face each other, and then heated and pressed together to form a hollow cell for the liquid crystal display element with a predetermined gap.
is injected and sealed to complete the liquid crystal display element.

The transfer of the liquid crystal display element of the present invention is constructed as described above, and its mechanism is such that the conductive silver paste 9 is applied to the surface of the spacer material 10. When the transfer material 9 penetrates the eight layers of peripheral sealing material, the spacer material 10 exerts a penetrating force,
Sufficient penetration is achieved and this spacer material 10
After the silver paste 9 applied to the surface of the transfer lead-out electrode 6 sufficiently contacts (adheres to) the opposing transfer lead-out electrode 6 and this transfer material 9 exerts a spacer effect, the adhesive force of the peripheral sealing material 8 causes the contact to be levered. Since the state is maintained stably, it is extremely stable against external pressure as shown in the figure, and as a result, ideal transfer conduction is achieved, no transfer conduction defects occur at all, and manufacturing yields are greatly improved. did.

Furthermore, according to the present invention, it is extremely easy to control the hardening state of the transfer material 9 before overlapping the electrode plates 1 and 2, and to control the hardening state of the peripheral sealing material 8. It was possible to set an extremely wide range of appropriate conditions such as temperature and time for heat-press bonding, and sufficient reproducibility was obtained. Furthermore, when the conduction performance of the transfer according to the present invention was evaluated at a relatively high frequency (2.0 KHz), it was found that a liquid crystal display element with no frequency dependence, excellent frequency characteristics, and high reliability could be easily obtained. .

In the above embodiment, alumina fine powder was used as the spacer material 10 corresponding to the gaps between the hollow cells mixed in the transfer material 9, but it is of course not limited to this. Yes, for example, even when using fine powders such as fused silica, quartz glass, soda glass, and other glasses, and powdered fibers, and not only insulators such as the above materials, but also metals. A similar effect can be achieved by using a conductive material or an organic material as a spacer.

Particularly, the maximum particle diameter of these spacer materials 10 is determined mainly by the required thickness of the cell, as is clear from its usage, and is usually in the range of several microns to +microns. Further, the average particle diameter is preferably 5 to 20 microns, but is not necessarily limited to this range. Also,
Although the case in which a silver paste is used has been described, the paste is not limited to an organic resin type, and may be a paste such as a glass type frit seal material.

As explained above, according to the present invention, by mixing the space material in the transfer material, the reliability of the device is improved, and high quality products can be manufactured easily and the yield can be increased. There is also a side effect.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the transfer of a liquid crystal display element, Figs. 2 and 3 are enlarged cross-sectional views of the liquid crystal display element for explaining the structure of a conventional transfer, and Fig. 4 is a diagram for explaining the structure of a conventional transfer. Figure 5 is a diagram illustrating the relationship between poor conduction of a transfer, heat-compression bonding conditions, and evaluation frequency depending on the method. Figure 5 is a diagram showing an equivalent circuit of a liquid crystal display element using a conventional transfer. Figure 6 FIG. 1 is an enlarged cross-sectional view of an embodiment of the present invention. 1 is a front electrode plate constituting a liquid crystal display element, 2 is a back electrode plate, 3 is a front display electrode, 4 is a back display electrode,
5 is a front side transfer electrode, 6 is a back side transfer lead-out electrode, 7 is a liquid crystal, 8 is a peripheral sealing material, 9 is a transfer material, and 10 is a spacer material. The same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A pair of electrode plates each having a display electrode and arranged with a predetermined gap therebetween via a sealing material;
A lead-out electrode provided on one of these electrode plates, a transfer electrode provided on the other electrode plate, a transfer material electrically connecting the transfer electrode and the lead-out electrode,
In the device having a liquid crystal material held in the gap, a conductive paste mixed with a spacer material is used as the transfer material, and the transfer material is applied to either the transfer electrode or the lead-out electrode. After that, it is brought to a predetermined hardening state, and a sealing material is applied around the electrode plate facing the transfer material-coated electrode plate and pre-cured, and then both the electrode plates are connected to the respective display electrodes and transfer electrodes. A method for manufacturing a liquid crystal display element, in which the lead-out electrodes are stacked one on top of the other so that they face each other and the transfer material penetrates through the sealing material, and are bonded under heat and pressure. 2. The method for manufacturing a liquid crystal display element according to claim 1, wherein the spacer material is made of alumina powder.