JPS634216A - Manufacture of liquid crystal element - Google Patents

Abstract

PURPOSE:To shorten an injection time and to manufacture a liquid crystal element effectively by injecting liquid crystal into a cell while applying pressure. CONSTITUTION:A hole 13 is formed in the nondisplay part of a glass substrate 11 by an ultrasonic working machine 12 and a transparent electrode 14, an oriented film 15 are formed on the internal surface of the substrate 11, and a transparent electrode 17 and an oriented film 18 are formed on the internal surface of a glass substrate 16; and the substrates 11 and 16 are set opposite each other and a seal agent 19 is arranged at the peripheral edge part and stuck to constitute a cell. Here, the air in the cell is discharged in a vacuum tank and a pipe 20 is dipped in the ferroelectric liquid crystal in a tank 22 and put back to the atmospheric pressure to inject liquid crystal in the cell. Then while the cell is heated by a plate type heater 23, a cylinder 24 which contains liquid crystal is fitted to the tip of the pipe 20 and the liquid crystal is further injected by pressure application. Then, the pipe 20 is caulked and cut and the cut part is sealed with an epoxy resin 21'.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a liquid crystal element suitable for, for example, a ferroelectric liquid crystal element having a matrix pixel structure, and particularly relates to a method of manufacturing a ferroelectric liquid crystal element into a cell. I'm curious about improvements.

"Prior art and its problems" When a ferroelectric liquid crystal exhibiting a chiral smectic C phase is sealed in the gap between two glass substrates with transparent electrodes formed inside, the spiral unravels and the optical axis is oriented in one direction. Line up. In this liquid crystal cell, the angle of the optical axis of the liquid crystal molecules changes due to the applied electric field, and by operating the liquid crystal molecules by sandwiching them between two polarizing plates, the Enoki refraction changes and light modulation occurs.

By the way, as a method for injecting liquid crystal into the inside of a cell, a so-called vacuum injection method is generally employed. That is, a liquid crystal cell is constructed by bonding the peripheral parts of the pair of substrates with a sealant, a part of the sealant is opened to form a liquid crystal injection port, and the liquid crystal cell is placed in a reduced pressure atmosphere to form a liquid crystal cell from the injection port. In this method, the air inside the cell is extracted, the injection port is immersed in a liquid crystal bath, the pressure is returned to atmospheric pressure, and the liquid crystal is injected from the injection port into the inside of the cell.

However, the above liquid crystal injection operation has the problem that as the area of the liquid crystal cell increases with the expansion of the display area, the liquid crystal injection time becomes longer and air bubbles tend to remain inside the cell. As described above, when air bubbles remain inside the cell, the air bubbles tend to disturb the alignment of the liquid crystal around the bubbles, resulting in poor display quality.

In particular, ferroelectric liquid crystals exhibiting a chiral smectic C phase have a higher viscosity than conventional nematic liquid crystals, and the gap between the upper and lower substrates is significantly smaller than that of TN type liquid crystal elements, so the above problems are brought into closer focus. I was able to do it.

In addition, ferroelectric liquid crystals exhibiting a chiral smectic C phase are heated to an isotropic liquid phase for the purpose of lowering the viscosity during injection, but as soon as they are cooled to room temperature, the viscosity increases and Since the fluidity of the liquid crystal is lost, the volume contraction of the liquid crystal due to thermal expansion is not alleviated, and bubbles may be generated when the cell is cooled.

``Object of the Invention'' The present invention was made in order to solve the problems of the prior art described above, and its purpose is to provide a method for manufacturing a liquid crystal element that allows ferroelectric liquid crystal to be reliably injected into the inside of a cell. It is about providing.

"Structure of the Invention" The present invention involves bonding two glass substrates with transparent electrodes formed inside to form a cell, and injecting a ferroelectric liquid crystal exhibiting a chiral smectic C phase into the cell to seal it. The method for manufacturing a liquid crystal device is characterized in that when liquid crystal is injected into a cell, the liquid crystal is injected while being pressurized by a liquid feeding means.

In this way, by injecting the liquid crystal into the cell while pressurizing it, even the highly viscous ferroelectric liquid crystal is injected into every corner of the cell, thereby preventing the generation of bubbles. Also, even if the liquid crystal is injected in a heated state and cooled to room temperature,
Since it is injected under pressure, the generation of bubbles due to contraction of the liquid crystal is also prevented. Furthermore, since the liquid crystal is injected while being pressurized, there is also the advantage that the injection time is shortened.

According to a preferred embodiment of the present invention, liquid crystal is injected into the cell in advance by a vacuum injection method, and the liquid crystal is injected while being pressurized by a liquid feeding means. In this way, when there is only one injection port, there is no possibility that the air existing inside the cell will interfere with the injection, and the liquid crystal can be smoothly injected.

According to another preferred embodiment of the present invention, two injection ports are formed in the cell, and when the liquid crystal is injected from one injection port and the inside of the cell is almost filled with the liquid crystal, the other injection port is closed. Inject while applying pressure. If you do this,
Liquid crystal P8 can be injected into the cell without requiring special equipment such as a vacuum injection method.

According to a particularly preferred embodiment of the present invention, a liquid feeding pump or a syringe is used as the liquid feeding means. When a liquid pump is used, there is an advantage that liquid crystal can be continuously injected into a large number of cells in a short period of time. In addition, when using a syringe,
It has the advantage of being able to inject liquid crystal with a simple operation using a simple device.

"Embodiment of the Invention" FIGS. 1(a) to (f) show an embodiment of the method for manufacturing a liquid crystal element according to the present invention.

As shown in FIG. 1(a), using an ultrasonic processing machine 12 or the like, a diameter of 0.5 nm is formed on the non-display part of one glass substrate 11.
A hole 13 of about +m is formed.

As shown in FIG. 1(b), a transparent electrode 14 and an alignment film 15 are formed on the inner surface of the glass substrate 11, and a transparent electrode 17 and an alignment film 18 are also formed on the inner surface of the other glass substrate 16. The glass substrates 11 and 16 are made to face each other, and a sealant 19 is placed on their peripheral edges, and the glass substrates 11 and 16 are bonded together to form a cell.

As shown in FIG. 1(C), a stainless steel vibrator 20@ is inserted into the hole 13 and fixed with an adhesive 21.

As shown in FIG. 1(d), after removing the air inside the cell in a vacuum chamber, the stainless steel vibrator 20 is immersed in a ferroelectric liquid crystal bath 22, and in that state is returned to atmospheric pressure, and the liquid crystal is injected into the cell.

As shown in FIG. 1(e), while heating the cell to about 100° C. with a plate heater 23, a syringe 24 containing liquid crystal is attached to the tip of the stainless steel pipe 20, and liquid crystal is further injected under pressure.

As shown in FIG. 1(f), the stainless steel pipe 20 is caulked, cut, and sealed with an epoxy adhesive 21. In this way, the liquid crystal 25 is sealed inside the cell, and a liquid crystal element is manufactured.

In this liquid crystal element, the ferroelectric liquid crystal 25 was injected into the cell under pressure, so even when the liquid crystal 25 was cooled to room temperature, no bubbles were observed due to volume contraction.

FIGS. 2(a) and 2(b) show another embodiment of the method for manufacturing a liquid crystal element according to the present invention.

As shown in FIG. 2(a), two holes 13.13 are formed in the non-display portion of one glass substrate 11, and when a cell is constructed in the same manner as in the above embodiment, these holes 13.13 are formed.
A stereoscopic vibrator 20.20' is inserted into each,
The wire is fixed with adhesive 21.

As shown in Fig. 2(b), one stainless steel pipe 2
0 to the liquid feed pump 261Fr, and inject ferroelectric liquid crystal into the cell from the stainless steel pipe 20.

Air inside the cell flows out from the other stainless steel pipe 20°. When the inside of the cell is almost filled with liquid crystal in this way, the other stainless steel pipe 20' is closed by caulking or other means, and liquid crystal is roughly injected from one stainless steel pipe 20 under pressure. After the liquid crystal is injected under pressure, the stainless steel pipes 20 and 20'' are caulked and cut, and sealed with adhesive. The liquid crystal is injected while being heated by the plate heater 23.

In this liquid crystal element as well, the generation of bubbles was prevented by injecting the ferroelectric liquid crystal while pressurizing it with a liquid pump.

In each of the above embodiments, the hole 1 is formed in one glass substrate 11.
3 is opened and a Stealth Vibe 20 is inserted into it to form an injection port for the liquid crystal.
It is also possible to adopt a method such as providing an opening in 9 to use it as an injection port.

"Effects of the Invention" As explained above, according to the present invention, by injecting liquid crystal into the cell while pressurizing, even highly viscous ferroelectric liquid crystal can be injected into every corner of the cell. This prevents the formation of bubbles. Furthermore, even if the liquid crystal is injected in a heated state and then cooled to room temperature, since it is injected under pressure, the generation of bubbles due to shrinkage of the liquid crystal is also prevented. Furthermore, since the liquid crystal is injected while being pressurized, there is an advantage that the injection time is shortened.

[Brief explanation of the drawing]

Figure 1 (a), (b), (c), (d), (e
), (f) are cross-sectional views showing one embodiment of the method for manufacturing a liquid crystal element according to the present invention according to the steps;
) are cross-sectional views showing step-by-step another embodiment of the method for manufacturing a liquid crystal device according to the present invention. In the figure, 11 is a glass substrate, 13 is a hole, 14 is a transparent electrode,
15 is an alignment film, 16 is a glass substrate, 17 is a transparent electrode, 1
8 is an alignment film, 19 is a sealant, 20.20° is a stainless steel pipe, 21.21 is an adhesive, 22 is a liquid crystal tank, 2
3 is a plate heater, 24 is a syringe, 25 is a liquid crystal, and 26 is a liquid pump. Patent applicant: Alps Electric Co., Ltd. Figure 1 (a) Figure 1 (C) Figure 1 (e)

Claims (4)

[Claims] (1) A method for manufacturing a liquid crystal element, in which two glass substrates with transparent electrodes formed inside are bonded together to form a cell, and a ferroelectric liquid crystal exhibiting a chiral smectic C phase is injected into the cell for sealing. A method for manufacturing a liquid crystal element, characterized in that when liquid crystal is injected into a cell, the liquid crystal is injected while being pressurized by a liquid feeding means. (2) The method for manufacturing a liquid crystal element according to claim 1, in which the liquid crystal is injected into the cell in advance by a vacuum injection method, and then injected while being pressurized by a liquid feeding means. (3) In claim 1, two injection ports are formed in the cell, and when liquid crystal is injected from one injection port and the inside of the cell is almost filled with liquid crystal, the other injection port is closed. A method for manufacturing liquid crystal elements in which injection is performed while applying additional pressure. (4) A method for manufacturing a liquid crystal element according to any one of claims 1 to 3, in which a liquid-feeding pump or a syringe is used as the liquid-feeding means.