JPS6234129A - Manufacture of liquid crystal device - Google Patents

Abstract

PURPOSE:To heat the whole liquid crystal device in a pressure-reduced or vac uum atmosphere and to seal the gap between a couple of substrates completely with a liquid crystal part material by sealing the gap between the substrates except at the peripheral part, charging liquid crystal between the substrates, and providing a paste type liquid crystal member nearby an injection hole. CONSTITUTION:An oriented layer is provided on electrodes of the substrates 1 and 1' of the liquid crystal device on the sides of opposite charged surfaces 8 and 8'. Further, a sealing material 18 of resin is formed at the peripheral part of one of the substrates 1 and 1' and a barrier 18' is formed at the outer peripheral side of the injection hole 19. Further, the solid liquid crystal material 2 is provided on one charged surface 8 or 8' of the substrate 1 or 1' and the substrates 1 and 1' are put in a vacuum container 100 hermetically. A heater 3 is arranged under the space 4 of the container 100 and a heat sink is constitut ed between the heater 3 and substrate 1 to realize gradual cooling and slow heat rising and falling. Then, the liquid material 2 of the liquid crystal device is heated into a liquid state and the pressure reduction in the vacuum atmo sphere is relaxed to inject the liquid crystal into the gap between the substrates 1 and 1' from the injection hole 19.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a liquid crystal device including a liquid crystal display device, and relates to a method for manufacturing a liquid crystal device including a liquid crystal display device. In particular, the present invention relates to a method of filling a gap between a pair of substrates with, for example, ferroelectric liquid crystal (hereinafter referred to as FLC). The present invention also relates to a method for manufacturing a liquid crystal display device for a display unit of a microcomputer, word processor, television, etc., or a liquid crystal disk memory device by using this liquid crystal and providing a guest-host type or birefringence type display panel.

``Prior Art'' For solid-state display panels, a system in which each picture element is controlled independently is effective for large-area displays. Conventionally, such a panel uses a dual-frequency liquid crystal, such as a twisty nematic liquid crystal (hereinafter referred to as TN liquid crystal), and is driven by multiplexing in a simple 71-lithography configuration of 44-format size with 400 elements in the horizontal direction and 200 elements in the vertical direction. A display device using a two-way display is known.

When such a TN liquid crystal is to be filled between a pair of substrates, the low viscosity of this TN liquid crystal is utilized.

That is, a pair of glass substrates are opposed to each other with a gap of 5 to 10 μm, and after spacers are spread between the glass substrates, a sealant for sealing is applied to the periphery of the pair of glass substrates, and the glass substrates are brought into close contact with each other. At this time, a portion of the surrounding seal portion is not sealed, and the injection port remains. Thereafter, the pair of substrates whose peripheries have been sealed are held in a vacuum container, and the whole is evacuated.

Further move the substrate and remove the TN pre-held in the vacuum container.
Immerse the injection port of this hole in the liquid crystal solution.

Furthermore, by bringing the inside of the vacuum container to atmospheric pressure, the TN liquid crystal solution is spread between the pair of substrates by 5 to 10 μm using capillary action.
It was intended to be injected into the gaps between them.

``Problems to be Solved by the Invention'' However, this method is excellent when a liquid crystal, such as TN liquid crystal, which maintains a low viscosity state even at room temperature is filled between the substrates. However, (1) this method cannot be applied at all to highly viscous liquid crystals in the form of paste or solid state liquid crystals, such as smectic liquid crystals exhibiting an SmC'' phase.

(2) The distance between the electrodes of the cell is 4 μ or less, preferably 0.5 to 3
When using a liquid crystal material that requires the use of a narrow gap of μ, it takes an extremely long time to fill the liquid crystal material.

(3) During filling, nearly 90% of the liquid crystal material adheres to the edge of the substrate near the opening and is not effectively used, resulting in much waste.

It has many disadvantages such as.

The present invention solves this problem.

"Means for Solving the Problem" In order to solve this problem, the present invention intentionally leaves some injection ports in the peripheral area of the pair of WANs before filling the pair of substrates with liquid crystal. to seal. Furthermore, a barrier is formed around the injection port for filling the liquid crystal material to prevent the liquid crystal from leaking outside. In particular, a barrier is simultaneously formed using a sealant around the periphery of a pair of substrates. Next, the pair of substrates are pasted together with a certain gap between them, and the periphery is sealed. Next, a solid or pasty liquid crystal material is placed near this injection port. Thereafter, the space between the pair of substrates separated from each other is held in a vacuum container, and the atmosphere in the gap between the pair of substrates is evacuated. The liquid crystal material is further heated to a liquid state, and the injection port is plugged with the liquid crystal material. At this time, this liquid crystal material is stopped by a barrier to prevent it from leaking to the other side. Further, the amount of this liquid is adjusted in advance so that it is sufficient for adhesion within a predetermined gap between the pair of substrates. Furthermore, this vacuum container is brought to atmospheric pressure, and a liquid crystal material is injected from the injection port and spread over the entire surface to be filled. In this way, the liquid crystal material covers the entire surface to be filled, and the outer periphery of the injection port is blocked by the barrier. After this step, the whole is slowly cooled, and the injection port is further sealed with a photocuring agent using a sealing member.

In the present invention, smectic liquid crystal,
Particularly preferably, a ferroelectric liquid crystal exhibiting a smectic C phase (SmC") is used. That is, by setting the cell spacing to 4 μm or less, generally 0.5 to 3 μm, a state in which the helical structure disappears can be obtained. can.

"Function" By doing so, (1) the liquid crystal material can be effectively used without adhering to the edges of the substrate, etc.;

(2) Being solid or pasty at room temperature,
Since the liquid crystal material is placed at or near the injection port at atmospheric pressure and then transformed into a liquid state and injected into the pair of substrates, there is no need to mechanically move the substrates or the like within the vacuum container.

(3) Since a barrier is provided around the outer periphery of the injection port, when the liquid crystal material becomes liquid, it leaks out, allowing effective use.

(4) It is solid or paste-like at room temperature, and turns into a liquid when heated to close the injection port due to surface tension, making it easy to encapsulate and inject into small-area panels.

(5) Since multiple injection ports can be provided instead of one, a large area (equivalent to A4 size) is possible even with a thin cell with a gap between substrates (cell thickness) of 4 μm or less.

(6) Even if a liquid crystal material with high viscosity is used, the time required for the sealing operation is about the same as the time required for injecting TN, since the temperature is raised during sealing to reduce the viscosity.

(7) A liquid crystal material can be laminated in the same process with an active structure in which an active element and an electrode connected to the active element are provided on one substrate side, or a passive structure in which no active element is used at all.

The present invention will be explained below according to examples.

"Example 1" FIG. 1 shows the manufacturing process of the liquid crystal device of the present invention.

The first prong (A) has two substrates (1), (1').

Electrodes are respectively provided on the opposing filling surfaces (8) and (8'). Also, to display in color,
A color filter is provided on one side between the electrode and the substrate or between the electrode and the filled liquid crystal. Further, the upper surface of this electrode is subjected to a known alignment treatment.

In these drawings, for the sake of simplicity, illustration is omitted and it is simply represented as an ice plate. However, it is effective to perform these electrodes, filters, alignment treatment, formation of a black matrix masking treatment (mask), production of active elements, etc. on opposite sides of a pair of substrates, as necessary.

The substrate is generally a glass substrate such as Corning 70
59 is used. However, it is effective to use a flexible substrate for one or both of the substrates. The flexible substrate is a chemically strengthened glass substrate with a thickness of 0.3 to 0.6 mm, or polyimide.

It is effective to use a light-transmitting heat-resistant organic resin substrate such as PAN or PET.

An alignment treatment layer is provided on the electrode on this substrate (1),
The upper surface was the surface to be filled. Furthermore, a sealant (epoxy or polyimide organic resin) is applied around one side of the board.
18) is formed by coating printing or the like. At the same time, a barrier (18') is formed around the outer periphery of the injection port. Next, the other aforementioned substrate (1°) was placed together and heated to harden the resin, thereby fixing the pair of substrates to each other with a constant spacing. The plan view is shown in Fig. 2 (8), and A-A'
, BB' longitudinal cross-sectional view is shown in Figure 2 (A-1), (
It is shown in A-2). FIG. 1 (8) is shown corresponding to FIG. 2 (8-1). Figure 2 shows the injection port (19).

(19") was set at two locations. However, this may be one location or more depending on the size of the panel.

Then, on this surface, apply FLC, for example, 58 (P-octyl.
Blend liquid crystals of oxybenzylidene-P'-amino-methyl butyl benzoate and 8-8 (9-ocluoxy-4'-biphenylcarboxylic acid-2-methylbutyl ester) (2), (2'') are provided. Since this liquid crystal is in the form of a paste at room temperature, it is sufficient to place the required amount on the substrate so that it slightly touches the surface.

The liquid crystal material may be filled with other FLCs or blends of FLCs. Regarding these FLCs, for example, JP-A-59-118744. Japanese Patent Application Publication No. 5
9-118745 and JP-A No. 59-98051 may be used.

Liquid crystal (2) was dropped onto the filling surface of one of the pair of substrates.

A pair of substrates (1) and (1') provided with such a solid liquid crystal material (2) were sealed in a vacuum container (100) as shown in FIG. 1(B). This vacuum container (100) has a space (4) on the container side (10) and has a lid (10°). A heater (3) was provided below the space (4), and a sink (heat sink) was formed between the heater and the substrate to enable slow cooling and gradual temperature rise and fall.

On this heater (3) is a pair of substrates (
1), (1') is arranged, and! (10'), then close the valve (13) as shown in Figure 1 (B).
Open the valve (12) and use the vacuum pump (14) to pump the space (4) inside the vacuum container (100) and the gap (
4゛) was sufficiently reduced or evacuated. Preferably 1
Vacuum was applied to 0-3 to 10-' torr. This gap (4°) is used for degassing from the injection port, but since the liquid crystal material is kept at room temperature and is in a solid or paste state, the injection port is not blocked by the liquid crystal material, and a vacuum is released from the gap. Can be pulled.

Furthermore, after this, this substrate is heated to a predetermined temperature of room temperature to 150°C, for example, a temperature at which the viscosity of the liquid crystal is sufficiently low (70 to 150°C).
Heating was controlled at 20°C, for example 100°C. Then, the liquid crystal (2) already provided in the area surrounded by the barrier (18'') on the substrate (1) becomes liquid crystal rather than paste-like liquid crystal, spreads over the entire area, and closes to the injection port ( 19).

Then, as shown in FIG. 1(C), gradually open the valve (13) to supply air or nitrogen (11').
' into the vacuum container (100).

Then, as shown in FIG. 1(C), the liquid crystal (2) enters the injection port (19) between the pair of substrates (1) and the (1°) gap.
It is injected (encapsulated). This gas (11') can be applied to the liquid crystal material from the injection port (11') at a pressure of 1 kg/cm2 at atmospheric pressure.

In addition, when further pressurizing with nitrogen, 2 to 1 atm or more
A pressure of 5 kg/cm" is also possible.

After this, the heater was gradually lowered to room temperature in FIG. 1(C). Furthermore, the first space (4) is also set to atmospheric pressure and the vacuum container (1
The lid (10') of 00) was removed. The cell in which the liquid crystal was sealed between a pair of substrates was removed from the container to obtain the image shown in FIG. 1(D).

Furthermore, the photocurable organic resin (
20) and seal this part as well. This figure 1 (D
) is shown in FIG. 2(A). In addition, the vertical cross-sectional views of AA' and B-B' in Figure 2 (A) are shown in Figure 2 (B-1).
, shown in (B-2).

Thus, as shown in FIG. 1(D), the two opposing substrates (1), (1') were able to form a sandwich configuration in which the liquid crystals (2) were substantially superimposed on each other.

In this way, it was possible to establish a method for filling and sealing a liquid crystal such as the smectic liquid crystal of the present invention (having a high viscosity at room temperature or in a solid state, especially FLC) between substrates.

"Effect" By doing so, A4 size (20cm x 30cm
0.2 cc of liquid crystal is sufficient for one sheet (area), and liquid crystal, which is more expensive than gold at 3,000 yen/g, can be used very effectively.
: One liquid crystal filling operation can be completed in a short time of about 5 hours.

The feature is that even if the area is large, the work time does not increase by increasing the number of injection ports.

In addition, in the conventionally known filling operation of TN liquid crystal,
Sealing the liquid crystal required moving the substrate and other parts in a vacuum. However, the present invention relates to a method for manufacturing a liquid crystal device that is effective in filling the gap between a pair of substrates with a liquid crystal material that is solid or paste-like at room temperature and liquid-like at high temperatures. be.

In the liquid crystal display device of the present invention described above, a polarizing plate can be provided on the outside of one or both of the substrates to make it a guest-host type or a birefringent type.

That is, when this liquid crystal display device is used as a reflective type, one polarizer is used, and the electrode on the incident light side is made translucent, and the other is made a reflective type electrode.

This can be achieved by using a guest-host type liquid crystal material and adding, for example, 3% of an anthraquinone dichroic dye to chemical compound C. At this time, if an FLC having a tilt angle of about 45 degrees is used, the contrast ratio can be increased.

On the other hand, when using two polarizers to create a transmissive type or a birefringent type with reflective μs, the two polarizers are oriented on the outside of each substrate, and the tilt angle of the FLC is adjusted to approximately 22.5 degrees. This can be achieved by doing this. Regarding the amount of light transmitted, a display can be obtained by irradiating the bank light with an EL (electroluminescence) fluorescent lamp or natural light and controlling the amount of light transmitted. It can be displayed by using a reflective type or by disposing a reflecting plate on the outside of a four-sided polarizer to reflect the incident light back to the incident surface side.

In the case of colorization, a color filter may be provided above or below the electrode on the other opposing substrate side (the side visible to the human eye).

Further, in the present invention, a non-linear element arranged on a substrate and an electrode provided above the substrate can be treated as a substrate, and an active element type can be obtained. In such a case, a 5CLAD (space charge limited current type amorphous semiconductor device) having a composite diode structure such as an NIN type or an insulated gate type field effect semiconductor device can be used as the nonlinear element.

In the liquid crystal display device of the present invention, display and reading can be performed by forming a dot-shaped photosensor using a light pen.

The liquid crystal device of the present invention is effective not only for liquid crystal display devices but also for other applied products using liquid crystals. Examples of applied products include disk memory devices, speakers, infrared sensors, printers, etc.

[Brief explanation of the drawing]

FIG. 1 shows a method for manufacturing a liquid crystal device of the present invention. FIG. 2 shows a liquid crystal device of the present invention.

Claims (1)

[Claims] 1. A method for manufacturing a liquid crystal device in which a pair of substrates are opposed with their surfaces to be filled inside and liquid crystal is filled between the surfaces to be filled, in which a portion of the peripheral portions of the pair of substrates is a step of providing an injection port in the part of the pair of substrates to fill the inside of the pair of substrates with liquid crystal; providing a solid or paste-like liquid crystal material at or near the injection port; and reducing the pressure of the entire structure. a step of holding the liquid crystal material under or under vacuum; a step of heating the liquid crystal material to make it into a liquid state; and a step of reducing the pressure or reducing the degree of pressure reduction of the vacuum atmosphere to transfer the liquid crystal material between the pair of substrates. 1. A method for manufacturing a liquid crystal device, comprising the step of filling a gap in a gap through an injection port. 2. A method for manufacturing a liquid crystal device according to claim 1, characterized in that when the liquid crystal material is liquefied around the injection port, a barrier is formed to prevent it from leaking outside.