JPS61193124A - Manufacture of liquid crystal cell - Google Patents

Abstract

PURPOSE:To prevent irregularity in display and local variance in responsibility by sandwiching a thin plate coated with a material which can fuse or sublimate between a couple of light-transmissive resin films provided with a transparent electrode, and then adhering the couple of substrates mutually and charging liquid crystal in a space formed after the thin plate materials are drawn out. CONSTITUTION:Two light-transmissive resin films 14 are used and a transparent electrode 16 is formed of indium oxide in a plane state on their one-surface sides. The stainless steel plate 10 coated with a film 12 is sandwiched with transparent electrodes 16 out and peripheral edge parts of the light-transmissive resin films 14 are heat-sealed to attain vacuum packing. The stainless steel plate 10 is sandwiched between glass plates 18 and 18 so that one side part projects, and the glass plates 18 and light-transmissive resin films 14, and peripheral edge parts of the glass plates 18 and 18 are adhered airtightly with a poly(vinyl butyral) 20. The stainless steel plate 10 are drawn out from between the light-transmissive resin films 14 and 14 after the film 12 is removed, and liquid crystal 24 which has a dynamic scatter mode is injected into the formed space under a vacuum.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for manufacturing a liquid crystal cell, and particularly to a method suitable for manufacturing a liquid crystal cell having a large area and a curved surface.

(Prior Art and its Problems) A liquid crystal cell is generally manufactured by bonding a pair of substrates provided with transparent electrodes at their peripheral edges, and then filling a space between the substrates with liquid crystal. However, in liquid crystal cells manufactured by such a method, when the area of the substrate is large, there is a problem in that errors occur in the thickness of the liquid crystal filling space and the distance between the transparent electrodes due to the warpage of the substrate.

Particularly, in the case of a substrate having a curved surface, it is difficult to process the substrate surface into a desired shape, and the same problems as described above occur significantly due to processing errors.

For example, in recent years, in vehicles such as automobiles, it has been considered to use liquid crystal cells in moonroofs, sun visors, or windshields so that the light entering the vehicle interior can be electrically adjusted. Since liquid crystal cells used for such purposes have a large area and a curved surface, it has been difficult to employ those manufactured by the above-mentioned conventional methods. In the liquid crystal cell manufactured according to the conventional method,
As mentioned above, errors in the thickness of the space in which the liquid crystal is enclosed and the distance between the transparent electrodes occur due to processing errors on the substrate surface or warping of the substrate, which may cause display unevenness or localized changes in response. This is because variations may occur.

(Means for Solving the Problems) The present invention was made based on the above-mentioned circumstances, and its gist is to cover a thin plate material with a material that can be melted or sublimated and to cover it with a transparent electrode. After being sandwiched between a pair of light-transmitting resin films provided, the pair of substrates are bonded to each other with the pair of light-transmitting resin films in between, and then the material covering the i-plate material is melted or sublimated. The thin plate material is pulled out from between the pair of translucent resin films, and the liquid crystal is sealed in the space formed after the thin plate material is pulled out.

(Effects of the Invention) According to such a method, warpage of the substrate and processing errors on the substrate surface can be reduced by changing the thickness of the adhesive layer interposed between the translucent resin film and the substrate when bonding the substrates together. The thickness of the liquid crystal enclosing space is maintained at the thickness of the thin plate coated with a meltable or sublimable material. Therefore, the thickness of the liquid crystal enclosed space can be controlled with high precision by controlling the thickness of the thin plate material and the thickness of the material covering the surface thereof. In addition, when the transparent electrodes are provided on the sides facing each other of a pair of translucent resin films, the distance between the transparent electrodes can be controlled by controlling the thickness of the thin plate material and the material covered thereon, as described above. By doing so,
In addition, when one or both are provided on the side that does not face each other, high precision can be achieved by controlling the thickness of the thin plate material and the material coated on it as well as the thickness of the translucent resin film. It can be controlled with.

In other words, according to the method of the present invention, the thickness of the liquid crystal enclosed space can be controlled with high precision, and the distance between the transparent electrodes can be controlled with high precision. It is possible to manufacture a liquid crystal cell that is free from defects such as display unevenness and local variations in response, unlike liquid crystal cells.

Moreover, according to the present invention, even if the substrate of the liquid crystal cell is flat or curved, transparent electrodes can be formed while keeping the light-transmitting resin film surface flat. Therefore, there is an advantage that the transparent electrode can be formed uniformly with substantially constant strength. Incidentally, it was extremely difficult to form a transparent electrode uniformly and with substantially constant strength on a curved surface.

As mentioned above, the present invention was made for manufacturing a large liquid crystal cell having a curved surface, which is used particularly for vehicle moon roofs, sun visors, windshields, etc.; It can also be used to manufacture liquid crystal cells and liquid crystal cells with a relatively small area.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. In this example, a case will be described in which a liquid crystal cell that can be used in a side window of an automobile is manufactured.

First, as shown in FIG.
0 was manufactured, and the entire surface of the stainless steel plate 10 was coated with a soluble substance that can be dissolved in water (in this case, pullulan; trade name; manufactured by Taisho Biological Research Institute) to form a film 12 with a uniform thickness of 100 μm. did. On the other hand, as shown in FIG. 1(b), two transparent resin films 14 made of PET (polyethylene terephthalate) with a thickness of 100 μm are prepared, and each is placed on one surface of the film and maintained in a flat state. In this state, a transparent electrode 16 made of indium oxide (in203) was formed. Then, as shown in FIG. 1(C), the stainless steel plate 10 covered with the film 12 is sandwiched between the transparent resin films 14, with the transparent electrodes 16 located on the outside. The peripheral edges of the film 14 were thermally welded and vacuum banked.

After that, the vacuum-backed stainless steel plate lO was
As shown in Figure +d), a pair of glass plates 18 and 18 as substrates prepared in advance are sandwiched with one side protruding, and polyvinyl butyral 20 is placed between each glass plate 18 and 14 translucent resin films and The peripheral edges of the glass plates 18 and 18 were airtightly bonded. Note that soda lime glass was used for the glass plates 18 and 18. Also, in the figure, glass+i18.18 is shown as a flat plate, but in reality,
It has a quadric surface shape with a slight curvature.

Next, as shown in FIG. 1(G), the glass plate 18
．． The portion of the translucent resin film 14 protruding from 18 was removed to expose the coating 2, and the coating 12 was removed by immersing it in a tank filled with warm water.

After removing the film 12, the stainless steel plate 10 is extracted from between the translucent resin films 14 and 14, and a dynamic scattering mode is exhibited in the space formed after the extraction, as shown in FIG. 1 (fl). The liquid crystal 24 was injected under vacuum, and after the injection, the injection port of the liquid crystal 24 was sealed with an epoxy resin adhesive 22.

Transparent electrode 1 of the liquid crystal cell manufactured in this way
A voltage was applied for 6.16 hours to make the liquid crystal cell cloudy, and its response state and display state were observed.

As a result, a cloudy state was obtained almost simultaneously over the entire surface of the liquid crystal cell, and it was found that there were no local variations in response. Further, a substantially uniform cloudy state was obtained over the entire surface of the liquid crystal cell, and it was observed that no display unevenness occurred. "In this way, since there is no display unevenness over the entire surface of the liquid crystal cell and uniform responsiveness is obtained, it is possible to avoid distance errors between the glass plates 18 and 18 due to processing errors and warping of the glass plates 18 and 18. is absorbed as a change in the thickness of the polyvinyl butyral layer 20 during adhesion of the glass plate 18.
The thickness of the liquid crystal enclosed space formed after drawing out the liquid crystal cell is uniformly determined over the entire surface of the liquid crystal cell by the thickness of the stainless steel plate 10 covered with the film 12. It is recognized that the thickness is uniformly determined by the thickness of the stainless steel plate 10 covered with the film 12 and the thickness of the pair of translucent resin films 14.

Although one embodiment of the present invention has been described above, this is literally an illustration, and the present invention should not be interpreted as being limited to this specific example.

For example, in the above embodiment, a 10 μm stainless steel plate 10 was used as the thin plate material, but it is also possible to use other gold plate plates such as spring steel, which have relatively high rigidity, as the thin plate material. The thickness can also be changed as appropriate within the range of about 5 to 20 pm depending on the situation.

Furthermore, the material to be coated on the thin plate material is not limited to the pullulan used in the above embodiments, but may be other water-soluble substances, or may be soluble substances that can be removed with an organic solvent. Furthermore, naphthalene and camphor can be removed by heating.

Alternatively, a sublimable substance such as ammonium bicarbonate (NH48C03) may be used. In addition, there is no problem with the thickness of the coating made of these materials as long as the thin plate material can be pulled out from between the translucent resin films after their removal and the thickness can be precisely controlled. teeth,
It will be set appropriately from a range of about 50 to 200 pm depending on the situation.

In addition, in the above embodiment, the translucent resin film 16 has a
Although 0 μm PET was used, it is also possible to use other resin films such as PE5 (polyether sulfone), and the thickness can be changed as necessary within the range of about 10 to 300 μm. Can be done.

Furthermore, in the above embodiment, indium oxide was used as the material for the transparent electrode 16, but tin oxide (Sn○2)
It is also possible to employ other transparent electrode materials such as ITO (In203 5n02).

Furthermore, the transparent electrodes do not necessarily have to be located on the surfaces of the translucent resin film that are separated from each other as in the above embodiments, but one or both of them can be used as shown in FIGS. 2 and 3. It may be provided on the surfaces of the translucent resin films that face each other.

Note that if the transparent electrodes are provided on the surfaces of the translucent resin films that face each other, the distance between the transparent electrodes will be correspondingly shortened, so that the driving voltage can be reduced. There is also the advantage that the control of the thickness of the transparent resin film can be relaxed.

Further, in the above embodiment, the glass plate 18.18 made of soda lime glass was used as the substrate, but the substrate is not limited to this, and other components such as glass or resin may be used depending on the purpose of use. It can also be used as a substrate, and adhesives other than polyvinyl butyral can also be used to bond the substrate and the transparent resin film, such as ultraviolet curing resin or Duramin film (trade name: Takeda Pharmaceutical Company Limited). It is possible to use the following products:

Furthermore, the liquid crystal that can be sealed between the transparent resin films is not limited to one that exhibits a dynamic scattering mode when a voltage is applied between the transparent electrodes, and any type of liquid crystal that can be sealed depending on the purpose can be sealed. It is also possible to use other adhesives such as acrylic resin as the adhesive for sealing the liquid crystal injection port. In addition, if alignment treatment of the liquid crystal is required, a self-aligning agent may be mixed into the liquid crystal, or the translucent resin film may be subjected to rubbing or the like in advance.

Further, in the above embodiment, a case was described in which a liquid crystal cell that can be applied to a side window of an automobile is manufactured. However, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to the production of large-area, curved liquid crystal cells that can be applied to window glasses, etc., and comparatively large-area, curved or planar liquid crystal cells that are used for ordinary displays.

Although not listed here, it goes without saying that the present invention can be practiced with various modifications and improvements within the scope of not forming a film.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a step in one embodiment of the method of the present invention, and FIGS. 2 and 3 are diagrams for explaining a step in another embodiment of the method of the present invention ( It is a figure corresponding to C). 10. Stainless steel plate (thin plate material) 12: Film 14: Transparent resin film 16: Transparent electrode 18. Glass plate (substrate) 20: Polyvinyl butyral Applicant 1 - Yota Automobile Co., Ltd. Figure 1

Claims (1)

[Claims] A thin plate material coated with a material that can be melted or sublimated is sandwiched between a pair of transparent resin films provided with transparent electrodes, and then a pair of substrates is bonded to each other with the pair of transparent resin films sandwiched between them. Thereafter, the material covering the thin plate material is removed by melting or sublimation, the thin plate material is pulled out from between the pair of translucent resin films, and a liquid crystal is sealed in the space formed after the thin plate material is pulled out. A method for manufacturing a liquid crystal cell, characterized in that: