JP2548987B2 - Liquid crystal display element manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a liquid crystal display device, and more specifically, to a gap between electrode substrates of a liquid crystal display unit without scattering glass fibers or the like between the electrode substrates. The present invention relates to a method for producing a liquid crystal display element having a uniform thickness, and can be used very effectively, particularly for a magnified projection liquid crystal display element.

(Prior Art) As a method of manufacturing a liquid crystal display element, a pattern is printed on each of two electrode substrates made of a transparent material such as glass using an adhesive agent by a screen printing method or the like. There is a method of forming a space between both electrode substrates while maintaining a gap (hereinafter referred to as a gap), and then injecting a liquid crystal into the space by using a pressure difference from the atmosphere using a vacuum device.

FIG. 2 shows a schematic view of a liquid crystal cell used in this method. In FIG. 2, 1 is a liquid crystal cell, 3 is an electrode substrate, 5 is an adhesive layer, and 7 is a space.

A glass fiber 9 or the like is used as a gap holding material for holding the gap, and these are used as the space 7 and the adhesive layer 5.
They are studded inside and hold the gap between the electrode substrates 3 facing each other.

On the other hand, when injecting the liquid crystal material, as shown in FIG.
The liquid crystal L to be injected and the liquid crystal cell 1 are placed in the vacuum container 11, the interior of the vacuum container 11 is depressurized, and the liquid crystal injection port previously formed in the liquid crystal cell 1 is dipped in the liquid crystal L to make the vacuum container 11 The inside is returned to atmospheric pressure. At this time, the pressure may be returned to normal pressure using an inert gas such as nitrogen.

When the inside of the vacuum container 11 returns to atmospheric pressure, the liquid crystal L is injected into the space 7 through the injection port, the liquid crystal L is filled in the space 7, and then the injection port is sealed with an adhesive or the like.

In the above injection process, when the inside of the vacuum container 11 returns from the reduced pressure state to the atmospheric pressure state, that is, when the space 7 is about to be filled with the liquid crystal material, a great pressure is applied to the electrode substrate 3 forming the space 7. It takes.

This is due to the pressure difference between the inside and the outside of the space 7, and this pressure acts to narrow the gap of the liquid crystal cell 1 as shown in FIG. 4, and secures a uniform gap over the entire liquid crystal cell 1. It is one of the factors that prevent

Therefore, as shown in FIG. 2, a gap retaining material having the same diameter such as glass fiber 9 is scattered in the space 7 to prevent the electrode substrate 3 from warping and obtain a uniform gap. .

(Problems to be Solved by the Invention) On the other hand, when a gap maintaining material such as glass fiber 9 is studded in the liquid crystal display portion, its diameter is about 10 μm.
Since it is so small, it is hardly noticeable in a display device intended for direct viewing with the naked eye.

However, since the liquid crystal display element used for a projector is characterized in that the whole is enlarged to a large screen, even a minute defect is enlarged and conspicuous.

That is, the liquid crystal display device having the above-described structure cannot be used for the liquid crystal display device for the purpose of magnifying projection.

However, here, the gap maintaining material such as the glass fiber 9 is removed from the liquid crystal display section and only the peripheral adhesive layer 5 is used.
When the gap is to be secured, the liquid crystal filling method described above reduces the gap around the middle portion of the display portion, which is the most flexible, as shown in FIG. This non-uniformity of the gap appears as non-uniformity of display contrast, and has a great influence on the displayed image quality.

Under these circumstances, it is necessary for liquid crystal display elements used for magnifying and projecting purposes to secure a uniform gap throughout the display section without using a gap retaining material inside the display section. It is preferable that the gap error be within ± 0.2 μm. This has an extremely important meaning in the application of the liquid crystal display device to the projector.

An object of the present invention is to provide a method for manufacturing a liquid crystal display element in which the gaps between the electrode substrates are kept uniform without scattering the gap maintaining material such as glass fiber in the display section.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention abuts a flat surface portion processed with high surface accuracy on an electrode substrate, and fills a space with liquid crystal while adsorbing the electrode substrate on the flat surface portion side. It is characterized by doing so.

(Function) Since the electrode substrate is fixed by the flat portion when the liquid crystal is filled, the pressure resulting from the pressure difference between the inside and the outside is not applied to the electrode substrate, and a liquid crystal display element in which a uniform gap is secured can be obtained.

Further, the liquid crystal display element can be manufactured without using the gap retaining material in the display portion, and can be used for magnifying projection.

(Example) Hereinafter, the Example of this invention is described according to drawing.

 FIG. 1 shows a schematic view of an apparatus for adsorbing an electrode substrate.

21 is a liquid crystal cell, 31 is an adsorption device, the two electrode substrates 23, 23 of the liquid crystal cell 21 have sufficient planarity, and both electrode substrates 2
3,23 is an adhesive layer with a gap retaining material provided around it
A space 27 is formed between both electrode substrates 23, 23 by being bonded via 25. In the figure, 27A and 27B respectively indicate a liquid crystal injection port and an exhaust port which communicate with the space 27.

The adsorption device 31 includes bases 33A, 33 corresponding to the two electrode substrates 23.
B is provided, and flat portions 35 processed with high surface accuracy are respectively formed in portions of the bases 33A and 33B facing the electrode substrate 23.

A plurality of intake passages 37 are formed in each of the bases 33A and 33B,
One end of the intake passage 37 of each of the bases 33A and 33B is opened to the flat surface portion 35,
The other end is connected to a vacuum source side such as a vacuum pump via a suction port 39.

Next, a case of filling the liquid crystal cell 21 with liquid crystal will be described.

When filling the liquid crystal, the liquid crystal cell 21 is mounted on each of the bases 33A and 33B.
Each flat surface portion 35 is brought into contact with the electrode substrate 23 so as to sandwich.

Next, the suction passage 37 and the suction port 39 are driven by driving a vacuum pump or the like.
The electrode substrate 23 is adsorbed on the flat surface portion 35 side via the
Then, the two electrode substrates 23 are fixed respectively.

Next, liquid crystal is injected into the space 27 from the liquid crystal injection port 27A.
The liquid crystal may be injected while suctioning the internal air from the exhaust port 27B, or the liquid crystal may be pressed while being pressed, or both may be used in combination.

Since the electrode substrate 23 is adsorbed and fixed to the flat surface portion 35 when the liquid crystal is injected, the flatness is maintained without being deformed by the pressure reduction or the pressure application at the time of the injection.

After the injection, if the pressure in the space 27 becomes equal to the external pressure, the electrode substrate 23 will not be deformed even if the adsorption by the adsorption device 31 is released.

After the injection, the liquid crystal cell 21 was sealed and the gap was measured. As a result, the gap error between the electrode substrates 23 was within ± 0.2 μm.

It is to be noted that the flatness of the two electrode substrates 23 is processed in advance with high precision, and that the electrode substrates 23 of the liquid crystal cell 21 before injection are
It is necessary that the gap between them is kept uniform over the entire surface.

(Effects of the Invention) As is apparent from the above description, according to the present invention, it is possible to manufacture a liquid crystal display element in which the gap between the electrode substrates is uniform over the entire display portion without using a gap retaining material. Since the liquid crystal display device manufactured by the present invention has no display defect due to the gap maintaining material, it is optimal as a liquid crystal display device for magnifying projection.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for adsorbing an electrode substrate, FIG. 2 is a schematic cross-sectional view of a liquid crystal cell, FIG. 3 is an explanatory view when injecting liquid crystal, and FIG. 4 acts on an electrode substrate when injecting liquid crystal. It is explanatory drawing of pressure. In the figure, 1 and 21 are liquid crystal cells, 3 and 23 are electrode substrates, 7 and 27 are spaces, 9 is glass fiber, 31 is an adsorption device, and 35 is a flat surface portion.

Claims (1)

(57) [Claims] 1. A method for manufacturing a liquid crystal display device by reducing the pressure of a space formed between two electrode substrates facing each other, and filling the space with a liquid crystal by utilizing a pressure difference. A method of manufacturing a liquid crystal display element, wherein a flat surface processed with high accuracy is brought into contact with the electrode substrate, and the space is filled with liquid crystal while adsorbing the electrode substrate.