JPS5855487B2 - liquid crystal display device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a liquid crystal display device.

Conventionally, liquid crystal display devices used in watches, calculators, etc. have a pair of substrates made of glass.

For this reason, when a thin liquid crystal panel is manufactured, the strength of the glass is weakened, making it vulnerable to drop impact and prone to breakage.

In addition, when manufacturing a curved liquid crystal panel for the sake of design development, it is extremely difficult to make the thickness of the liquid crystal layer uniform when two pieces of glass are placed facing each other.

The present invention has been made to improve the above-mentioned drawbacks.

That is, in the present invention, inorganic glass is used as one of the substrates constituting the liquid crystal panel, and this inorganic glass is etched to a desired shape and depth using a common aqueous solution containing hydrofluoric acid.

At this time, portions that are not to be etched are masked with resist or the like.

Furthermore, as another substrate, a plastic substrate such as methacrylic resin, polycarbonate, polyacrylate, polyolefin, etc. having excellent optical and chemical properties is used.

Transparent or opaque patterned electrodes for applying voltage to the liquid crystal are formed on each of the pair of substrates, and electrodes can be formed relatively easily on plastic by a method such as low-temperature sputtering.

A liquid crystal panel that combines a glass substrate and a plastic substrate as described above has the following advantages.

In other words, when a liquid crystal display is applied to a watch or the like, it is desirable to form it thinly due to design issues and its viewing angle characteristics, but when the thickness of the glass is made thinner, the strength becomes weaker and the display becomes particularly susceptible to drop impact.

Therefore, by making one of the substrates plastic, mechanical shock can be absorbed and the strength can be increased.

Furthermore, if both of the pair of substrates are made of plastic substrates, the plastic substrates become easily deformed, especially when the substrates become thin, so it is difficult to form a thin and uniform liquid crystal layer required for liquid crystal displays. becomes difficult.

On the other hand, when the pair of substrates are made of plastic, one of the glass substrates is smooth and not easily deformed, so the gap can be made uniform, and furthermore, as in the present invention, a gap of uniform depth can be formed on the glass substrate. This is especially easy if you are

Further, the present invention is particularly effective when the liquid crystal display has a curved surface.

In other words, when manufacturing a digital watch or the like with an excellent design, if the liquid crystal panel can be formed into a curved shape, it will be very elegant.

In order to manufacture a liquid crystal display panel having a certain curvature, conventional methods include polishing the glass to make it have a certain curvature, or thermally deforming the glass to make it have a certain curvature.

However, with this method, the glass has minute irregularities, and it is extremely difficult to form a uniform gap of about 10μ, which is required for a liquid crystal display, when a pair of substrates are assembled, so manufacturing is difficult. The drawback was that the yield was very low.

In the present invention, glass having a certain curvature has a desired depth,
For example, when glass and plastic substrates with a uniformly etched area of about 10 μm are placed facing each other, the plastic substrate is flexible, so the processing accuracy of each glass is as high as when a pair of inorganic glasses are combined. It is possible to easily manufacture a liquid crystal panel with a curved surface without the need for one.

Next, the present invention will be explained using examples.

Example 1 Borosilicate glass with a thickness of about 0.3 mm was etched with a hydrofluoric acid aqueous solution to a thickness of about 10 μm as shown in the cross-sectional view in Fig. 1, and then a conductive oxide film was formed by CVD. Furthermore, this conductive film was formed into a pattern necessary for a display, and its surface was subjected to a rubbing treatment so that the liquid crystal was homogeneously aligned.

Next, a conductive film of indium oxide was attached to a polyester film with a thickness of about 150 μm by low-temperature sputtering, and after etching the conductive film into a desired shape, the surface was rubbed so that the liquid crystal was homogeneously aligned.

The pair of substrates described above were stacked one on top of the other as schematically shown in cross-section in FIG. 2, and a liquid crystal panel having a thickness of about 10 μm was sandwiched therebetween to form a liquid crystal panel.

By arranging a pair of polarizing plates on both sides of this liquid crystal cell to form a TN type liquid crystal display, it was possible to manufacture a display with good impact resistance despite its thinness.

At this time, as shown in the cross-sectional view in Fig. 3, the thickness of the liquid crystal layer can be made even more uniform by providing minute columnar parts 7 for supporting the plastic substrate in areas that do not affect the display when etching the substrate glass. can do.

Example 2 Borosilicate glass having a thickness of approximately 0.5 mm was deformed by hot pressing to a curvature of 5 cfrLO, and then etched to a thickness of approximately 10 μm with an aqueous hydrofluoric acid solution.

After that, it was treated in the same manner as in Example 1, and combined with a polyester film that was treated in the same manner as in Example 1 and had a thickness of about 200μ.
By bonding with epoxy adhesive, a display device as shown in the cross-sectional view in FIG. 4 was manufactured.

By arranging a pair of polarizing plates on both sides of this liquid crystal cell to form a TN type liquid crystal display, it was possible to manufacture a liquid crystal display with a curved surface and an elegant design with good mass productivity.

At this time, since the plastic substrate 2 is deformed according to the curvature of the glass substrate 10 and is made integrally, the processing accuracy of the glass substrate 1 does not need to be so high, making manufacturing easy.

As described above, the present invention uses a plastic substrate and an etched inorganic glass substrate as the pair of substrates constituting the liquid crystal display, which provides excellent impact resistance and is extremely easy to produce for panels with curved surfaces. This has advantages such as being able to manufacture a display device with a uniform liquid crystal layer thickness.

[Brief explanation of the drawing]

FIGS. 1 and 3 are schematic cross-sectional views showing the shape of etched inorganic glass. FIG. 2 is a schematic cross-sectional view showing an example of the liquid crystal display of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a liquid crystal display having a curved surface according to the present invention. 1...Etched inorganic glass substrate, 2.
...Plastic substrate, 3, 4...Transparent electrode, 5...Seal/adhesive, 6...
liquid crystal.

Claims (1)

[Claims] 1. Using inorganic glass having a recessed portion of a desired depth as one of a pair of substrates constituting a liquid crystal display,
A liquid crystal display device characterized by using a plastic substrate as the other substrate. 2. The liquid crystal display device according to claim 1, wherein the glass has a curved surface.