JP2606687B2 - Liquid crystal device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device including a liquid crystal display device which is modularized, and relates to a lead terminal of an electric circuit connected to a display panel or a printed electric circuit. The terminal is also integrated to be manufactured. The present invention relates to a liquid crystal material having a high viscosity such as a smectic liquid crystal (hereinafter, referred to as Sm liquid crystal), particularly a ferroelectric liquid crystal (hereinafter, referred to as a Sm liquid crystal).
FLC) is effective. By using this liquid crystal and providing a guest-host type or birefringence type display panel, the present invention relates to a liquid crystal display device of a display unit such as a microcomputer, a word processor or a television, or a module thereof.

[Prior Art] In a solid-state display panel, a method of controlling each picture element independently is effective for a large area. Conventionally, such a panel uses a dual frequency liquid crystal, for example, a twisted nematic liquid crystal (hereinafter referred to as a TN liquid crystal), and uses a multiplex driving method in an A4 size simple matrix configuration with 400 elements in the horizontal direction or 200 elements in the vertical direction. 2. Description of the Related Art There is known a display device using the same.

When preparing such a TN liquid crystal, utilizing the low viscosity of the TN liquid crystal, a pair of glass substrates are opposed to each other with a gap of 5 to 10 μ, and after dispersing a spacer between the glass substrates, the pair of glass substrates is dispersed. A sealant for sealing is applied to a peripheral portion of the glass substrate, and they are brought into close contact with each other. At this time, a part of the peripheral seal portion is not sealed, and the injection port is left and provided. Thereafter, the pair of substrates whose periphery is sealed is held in a vacuum container, and the whole is evacuated. Then, the hole is immersed in a TN liquid crystal solution, and the inside of the vacuum vessel is brought to the atmospheric pressure.
The gap between 充填 10 μm was filled with liquid crystal. The peripheral portion is sealed by bringing the substrates into close contact with each other “inside” the substrate. For this reason, it has never been possible to use the sealing material for reinforcing the leads connected to the panel at the same time.

"Problems to be Solved by the Invention" Such a method is excellent when a liquid crystal having a low viscosity at room temperature such as a TN liquid crystal is filled between substrates. However, (1) the connection between the IC circuit board connected to the liquid crystal display panel and the lead terminals of the electric circuit or the printed electric circuit has a low mechanical mounting strength and is likely to cause low reliability.

(2) It takes a long time to manufacture the connection terminals of the electric circuit and the sealing work around the display panel.

(3) When a high-viscosity liquid crystal material is used on the premise that a narrow gap of 4 μm or less, preferably 0.5 to 3 μm is used between the electrodes of the cell, it takes a very long time to fill.

(3) When the liquid crystal material is filled into a large area, for example, an A4 size plate, a filling operation at a high temperature, for example, 120 ° C. for a long time of 8 to 10 hours is required. Therefore, the sealing material in the peripheral portion is deteriorated, and this sealing material is likely to be mixed as impurities into the liquid crystal.

(4) 90% of the liquid crystal material that is not used effectively during filling
% And is wasteful.

And so on.

 The present invention solves such a problem.

"Means for Solving the Problems" In order to solve such a problem, the present invention provides a pair of substrates having electrodes and leads mutually facing a surface having the electrodes and leads inward, and a liquid crystal between the electrodes. In a liquid crystal device filled with, a lead terminal of an electric circuit or a terminal of a printed electric wiring connected to the electrode / lead is provided so as to be connected to each other at a connection portion, and covers peripheral ends of the pair of substrates. A liquid crystal device, wherein the liquid crystal is sealed, and an organic resin film covering the connection portion is provided.

In order to fabricate the device of the present invention, the liquid crystal is placed on the filling surface of the pair of substrates instead of sealing the peripheral portions of the pair of substrates before filling the pair of substrates with the liquid crystal. And a pair of substrates are brought into close contact with each other via a liquid crystal. Furthermore, after this step, the outer periphery (around the end) of the pair of substrates is sealed with a curable resin. Furthermore, when sealing the outer periphery, the lead terminals (1040 in the case of a 640 × 400 pixel panel) attached to this panel were covered with this organic resin to achieve high reliability.

That is, a liquid crystal is provided on one of the surfaces to be filled which is separated from each other, a vacuum is maintained between the pair of substrates, and the liquid crystal material is liquefied by heating. Further, a lamination method is used in which the surfaces to be filled of the other substrate are brought into close contact with each other on the liquid crystal, and a pair of substrates is pressed from outside to a predetermined mutual position. Then, the liquid crystal material is spread over the entire surface to be filled. The liquid crystal material is thus spread over the entire filling surface. After that, the peripheral portions of the pair of substrates that are in close contact with each other via the liquid crystal and the lead terminals connected to the already-provided substrate (glass substrate) at the connection portion are again covered with the curable resin (thermosetting or thermosetting resin). Light curing), and the whole of them is evacuated again. Further, the organic resin of at least the peripheral portion and the connection portion is cured, and the peripheral portions of the pair of substrates are sealed with the resin, so that a second laminating step is provided.

In the present invention, a highly sticky liquid crystal such as a smectic liquid crystal, particularly preferably a ferroelectric liquid crystal exhibiting a smectic C phase (SmC ^* ) is used as a liquid crystal material. That is, a state in which the helical structure has disappeared can be obtained by setting the cell interval to 4 μm or less, generally 0.5 to 3 μm.

[Operation] By doing so, (1) fixation of each substrate with a sealing material around the cell, and the adhesion area is larger than in the conventional example in which only the substrate "inside" side periphery is used. It is possible to obtain a strong fixing strength against strain stress such as twisting a pair of substrates with each other.

(2) At the same time as the sealing of the peripheral portion of the display panel, the connection portion with the lead terminal or the printed electric circuit terminal of another electric circuit simultaneously formed on the peripheral portion of the substrate is covered. Further, mechanical connection / integration can be performed with higher reliability.

(3) The operation can be completed in a short time by simultaneously performing the sealing step of the first laminating step of the liquid crystal and the subsequent second laminating step of the peripheral part.

(4) The liquid crystal is spread over the entire surface to be filled by the first laminating step, and thereafter, the pair of substrates is precisely aligned with each other at a micro level. Further, after that, since the outer periphery is sealed in the second laminating step, the positions of the pair of substrates can be precisely arranged at a completed level.

(5) Since the liquid crystal is filled between the pair of substrates by the laminating operation, a large area (corresponding to A4 size) can be obtained even with a cell having a small gap (cell thickness) of 4 μm or less.

(6) 100% of the liquid crystal material provided on the substrate can be effectively used.

(7) Even when a liquid crystal material having a high viscosity is used, the lamination and sealing operations do not require 2 hours or more.

(8) A liquid crystal material can be laminated in the same process regardless of the active structure in which an active element and an electrode connected to the active element are provided on one substrate side or the passive structure in which no active element is used.

 Hereinafter, the present invention will be described with reference to Examples.

Example 1 FIG. 1 shows a process for manufacturing a liquid crystal display device of the present invention.

FIG. 1A has two substrates (1) and (1 '). Electrodes are provided on the opposing surfaces to be filled ((8) and (8 ')), and for color display, between one electrode and the substrate or between the electrode and the electrode. A color filter is provided between the liquid crystal to be formed.
Further, a known orientation treatment is performed on the upper surface of the electrode.

In these drawings, for simplicity, illustration is omitted and is simply represented as a substrate. However, these electrodes, filters, alignment treatment,
It is effective to form a shadowing process (mask) for forming a black matrix, manufacture active elements, and the like as necessary.

The substrate is generally a glass substrate, for example, Corning 70.
Use 59. However, it is effective to use a bendable substrate for one or both of the substrates. As the flexible substrate, it is effective to use a chemically strengthened glass substrate having a thickness of 0.3 to 0.6 mm or a light-transmitting heat-resistant organic resin substrate such as polyimide, PAN, or PET.

An alignment treatment layer (for example, an asymmetric alignment treatment layer) was provided on the electrode on this substrate, and the upper surface thereof was used as a filling surface. Then, on this surface, FLC such as S8 (P-octyloxybenzylidene-P'-amino-methylgatylbenzoate and B-9 (9-octyloxy-4'-biphenylcarboxylic acid-2-methylbutyl ester) Brand liquid crystal with Brent LCD etc. Other than this, BO
FLCs such as BAMBC or FLCs with multiple blends may be filled. Regarding these FLCs, for example, JP-A-56-107216, JP-A-59-118744, JP-A-59-118745,
A liquid crystal material disclosed in JP-A-59-98051 may be used.

Liquid crystal (2) was dropped on one of the surfaces (8) of the pair of substrates (1) and (1 ') to be filled.

A pair of substrates provided with the liquid crystal was sealed in a vacuum container (100) as shown in FIG. 1 (B). The vacuum vessel (100) has a first space (4) on the vessel side (10) and a second space (5) on the lid side (10 '). A heater (3) is provided below the first space (4), and a sink (heat sink) is formed between the heater and the substrate to allow slow cooling and gradual temperature rise and fall. . This heater (3)
One substrate (1) is disposed on the substrate, and the substrate is kept at room temperature to 17 ° C.
The heating was controlled to a predetermined temperature within 0 ° C., for example, 80 ° C. Then, the liquid crystal (3) already provided on the filling surface on the substrate (1) is heated and spreads on the filling surface. Before or after the liquid crystal was dropped, a spacer particle diameter of 2 μ was disposed on the substrate at a predetermined interval. The spacer may not be used at all.

Further, the other substrate (1 ') opposing above is placed in 0.1
They were placed 1010 mm, for example, 3 mm apart or slightly abutting each other.

Thereafter, the lid-side container (1) having the second space (5)
0 ′) was fitted to the container (10) by an O-ring.
Under the second space, the first space and the second space are shielded from each other by a layer having elasticity (hereinafter referred to as a syringe rubber (6) for simplicity). In the pressures of the second space and the first space, when the pressure in the first space is a positive pressure, the pressure expands downward, and when the pressure in the opposite space is a negative pressure, the pressure is pulled upward. This rubber is not limited to silicon rubber as long as it can withstand a temperature of 170 ° C.

These are joined together by an O-ring, and (11),
Vacuum was simultaneously drawn from (11 '). That is, these two outlets are connected to the vacuum pump (1) through valves (12) and (12 ').
4) Connected. And this valve (12), (1
2 ') was opened, valves (13) and (13') were both closed, and the first and second spaces (4) and (5) were both vacuum spaces.

Further, as shown in FIG. 1 (C), the other substrate separated from the upper surface was disposed at a predetermined position.

That is, the upper and lower substrates were aligned with each other so that the positions of the upper and lower electrodes did not shift. Then, the other second space (5) is changed from the vacuum state to the first space (4).
The valve (12 ') was closed and the valve (13') was gradually opened so that the pressure became a positive pressure, and the atmosphere or nitrogen was leaked to atmospheric pressure.

Then, as shown in FIG. 1C, the silicon rubber (6) expands downward and presses the other opposing substrate (1 ') against the one substrate (1). At atmospheric pressure, a pressure of 1 kg / cm ² can be applied. When nitrogen is supplied from (13 ') and further pressurized, the pressure may be 1 atm or more and 2 to 5 kg / cm ² .

Thus, pressure can be uniformly applied to the entire surfaces of the pair of substrates, and the liquid crystal was initially provided at one point or a plurality of points in a dot or plane by the pressure.
It spreads laterally along the surface of and is laminated.

Thereafter, the first space is also set to the atmospheric pressure, and the lid side container (10) of the container (100) is opened to complete the first laminating step.

Further, precise alignment of the pair of substrates is performed in a high temperature state where the viscosity of the liquid crystal is low. This precise alignment may be performed in the container (100) or on a hot plate at another position.

Next, a lead terminal of an electric circuit or a terminal of a printed electric circuit, particularly, for example, an FPC (flexible printed circuit, hereinafter referred to as FPC for simplicity) is connected to the peripheral portions of the pair of substrates by soldering. This connection was made using P-1000 or CP-2000 sold by Sony Chemical Corporation. This connection is disclosed, for example, in Electronic Technology (June 1984). The outer periphery of the pair of substrates to which the lead terminals were connected as described above was fixed with an organic resin.

That is, a pair of substrates in which an electric circuit (21) such as an FPC is connected in the container (100) of FIG. 1 (B), and curable resins (18), (18 ') and The protective organic resin (19) and (19 ') are provided. That is, the structure shown in FIG. 1D is disposed in the container shown in FIG. 1B, and the lid (10 ') is closed. Further, as in the first laminating step, the whole container is evacuated. Further, if a thermosetting resin is used as the curable resin, it is heated to a predetermined temperature, for example, 120 ° C.
Then, the thermosetting resin is softened temporarily and reaches the side surfaces of the pair of substrates. In order to improve the adhesion between the wraparound and the outer periphery and the outer periphery of the substrate, a vacuum evacuation step and a valve (13 ') are opened, and as shown in FIG. Curable resin (1
8), the step of pressing (18 ') is important. Then, the thermosetting reaction is completed.

Thus, the outer periphery including the outer periphery of the pair of substrates (cells) that are in close contact with each other via the liquid crystal (2) to which the FPC is connected is, as shown in FIG.
It is fixed with. For example, EVA (Ethylene Vinyl Alcohol) is used as the curable resin, and PES (Poly Ethylene) is used as a protective resin on the upper surface so that the EVA can withstand future actual use.
(Ether / sulfone) Thus, as shown in FIG. 1E, the pair of substrates and the terminals of the FPC can be fixed to each other and integrated.

Thus, if one of the pair of electrodes / leads (for example, the lower side) has a simple matrix electrode / lead structure in the X direction and the other in the Y direction only, this alignment accuracy can accept an accuracy of 1 to 3 mm. However, in the case of a rectangular electrode having a width of, for example, 400 μ ^□ and a stripe electrode having a width of 400 μ in the Y direction, the accuracy error is required to be ± 30 μm or less. In this case, as described above, in the step of FIG. 1D, precise positioning is performed. This positioning accuracy is determined by its use.

120 ° C (30 minutes), pressurization (5 minutes), 160 ° C (10 minutes)
The step (c) is performed, and the resin is thermally cured to crosslink and stabilize the curable resin to obtain FIG. 1 (E).

Thus, the liquid crystal is filled in the central part of the pair of substrates by the two independent laminating steps, and the sealing of the liquid crystal and the integration of the FPC with the glass substrate can be performed by fixing the organic resin in the outer peripheral part. Was. This seal is 2-10mm, for example 5m
A width of m was provided to enhance the adhesion between the substrates. F
It is preferable that the connection portion of the PC be covered and covered with the organic resin (18). However, covering only a part of the material is effective for mechanical security.

FIG. 2 shows (A-1) and (A) corresponding to (A) in FIG.
-2) and (A-3), which correspond to FIG.
-1) and (B-2). That is, FIG. 2 (A-3) is shown corresponding to FIG. 1 (A). The plan view of the upper substrate is (A-1), and the plan view of the lower substrate is (A-
See 2). FIG. 2 (B-2) corresponding to FIG. 1 (E).
Shown in This plan view is shown in (B-1). As is clear from these, each has an external connection area (17), (17 ') of the electrode provided on one side of the substrate. The external connection area is electrically connected to other external devices by FPC (flexible printed electronic circuit). Therefore, in FIG. 2 (B-1), the organic resin for sealing is FPC.
And connected to each other. It is effective to cover the external connection region and to increase the fixing strength in the connection region.

In this embodiment, in the state of FIG.
The FPC may be continuously provided for each substrate. In this case, since the FPC is also held in the laminating container during the steps shown in FIGS. 1B and 1C, there is a disadvantage that the container becomes unnecessarily large.

Embodiment 2 This embodiment is the same as Embodiment 1 except for the following steps. That is, a curable resin is previously applied to the upper substrate (1 ') in FIG.
It is arranged as shown in This pair of substrates (1),
In (1 '), the FPC has already been connected at the connection portion.

Further, the printed circuit is connected to a pair of substrates (1) and (1 ′) connected by a connecting portion and sealing resins (18) and (1).
8 ') is placed in a container (100) as shown in FIG. 1 (B), and a liquid crystal (2) is laminated as shown in FIG. 1 (C). That is, the first laminating step and the second laminating step are performed simultaneously.

 Thus, FIG. 1E can be obtained.

 Other than the above, it is the same as the first embodiment.

In this process, all operations can be performed at the same time, so that the operation time can be reduced. However, there is a disadvantage that the alignment accuracy of the pair of substrates is poor.

"Effect" By creating an A4 plate (20cm x 30cm area), the connection, which is the most problematic in reliability, was covered with organic resin, and high reliability was achieved. In addition, it has another feature that this step does not require any extra steps. 0.3cc is enough for one liquid crystal, 3000
Liquid crystals more expensive than gold / g and gold can be used very effectively.

The feature is that the working time does not increase even if the area is large.

 The entire area of the substrate can be used as a display.

That is, in the filling operation of the conventionally known TN liquid crystal,
It is characterized in that no stress is applied to the liquid crystal. Therefore, the effect of the sealant in the peripheral portion is to support each other's forces so that the pressure that can be applied to each substrate from the outside is not applied to the liquid crystal itself.

However, on the other hand, the present inventor has found that in the filling operation of the smectic liquid crystal having a large viscosity used in the present invention, even if this stress is applied to the liquid crystal itself, there is no problem in the orientation and reliability. By utilizing the property of withstanding the pressure, a manufacturing method according to the present invention, which is completely different from the conventional method, can be realized.

In the liquid crystal filling method of the present invention described above, the alignment treatment layer constituting the surface to be filled is subjected to an asymmetric alignment treatment, one is subjected to a rubbing treatment, and the other is a non-rubbing treatment. At this time,
After lamination as in the present invention, the substrate is slightly moved along a rubbed surface in a high temperature state or the like (1 μm or more to 1 to 10).
It is effective to shift by ⁴ μm) and apply stress to the liquid crystal to orient it.

In the above-described liquid crystal display device of the present invention, a polarizing plate can be provided outside one or both of the substrates to be a guest-host type or a birefringent type. When this liquid crystal display device is used as a reflection type, one polarizer is used, the electrode on the incident light side is made translucent, and the other is a reflection type electrode. This can be achieved by making the liquid crystal material a guest-host type, for example, by adding an anthraquinone dichroic dye to FLC, for example, 3% by weight. 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, in the case of a birefringent type which is a transmission type or a reflection type using two polarizing systems, the two polarizers are oriented to the outside of each substrate, and the FLC tilt angle is about 22.5 degrees. Can be achieved by doing so. In a light-transmitting type, a display can be formed by irradiating a backlight with an EL (electro-luminescence) fluorescent lamp or natural light and controlling the amount of transmitted light. In the case of the reflection type, display can be performed by disposing a reflection plate outside the polarizer on the back surface and reflecting the incident light toward the incident surface again.

In the present invention, if the polarizing plate withstands heat resistance, it can be fixed to the surface of the glass substrate simultaneously with sealing the outer periphery. Also, if the photo-curing method is used,
The polarizing plate can also be fixed together with the sealing of the liquid crystal.

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 is provided on a substrate, and an electrode provided thereon is treated as a substrate,
It can be an active element type. In such a case, it is possible to use an SCLAD (space charge limited current type amorphous semiconductor device) or an insulated gate type field effect semiconductor device having a composite diode structure such as NIN type as the non-linear element.

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

The liquid crystal device of the present invention is effective not only for a liquid crystal display device but also for other applied products using liquid crystal. Examples of the applied products include a disk memory device, a speaker, and an infrared sensor printer.

[Brief description of the drawings]

FIG. 1 shows a method for manufacturing a liquid crystal device of the present invention. FIG. 2 shows a plan view and a longitudinal sectional view of the liquid crystal device of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kaoru Koyanagi 7-21-21 Kitakarasuyama, Setagaya-ku, Tokyo Inside the Semiconductor Energy Laboratory Co., Ltd. (72) Inventor Shinji 7-21 Kitakarayama, Setagaya-ku, Tokyo No. 21 Inside Semiconductor Energy Laboratory Co., Ltd. (72) Inventor Toshiharu Yamaguchi 7-21-21 Kitakarasuyama, Setagaya-ku, Tokyo Inside (72) Inventor Mitsunori Sakuma 7-21 Kitakarayama, Setagaya-ku, Tokyo No. 21 Inside the Semiconductor Energy Laboratory Co., Ltd. (72) Inventor Takashi Inujima 7-21-21 Kita-karasuyama, Setagaya-ku, Tokyo Referee, Atsushi Mitsuda, Judge, Semiconductor Energy Laboratory Co., Ltd.Judge Shoji Ishikawa References JP-A-59-195222 (JP, A) JP-A-59-57221 (JP, A) JP-A-60-21028 (JP, A) JP-A-60-111221 (JP, A) JP-A-61-190313 (JP, A) JP-A-51-65656 (JP, A) JP-A-60-75817 (JP) , A) JP-A-59-171925 (JP, A)

Claims (2)

(57) [Claims] 1. A liquid crystal device in which a pair of substrates having electrodes and leads are opposed to each other with the surface having the electrodes and leads inside, and a liquid crystal is filled between the electrodes, and the substrates are connected to the electrodes and leads. The lead terminals of the electric circuit or the terminals of the printed electric wiring are connected to each other at the connection portion, and the organic resin covering the peripheral edges of the pair of substrates, sealing the liquid crystal, and covering the connection portion A liquid crystal device comprising a film. 2. The liquid crystal device according to claim 1, wherein the organic resin film presses the outer peripheries of the pair of substrates from the upper and lower surfaces to be in close contact with each other.