JPS59229526A - Liquid crystal display device provided with semitransmission type reflecting plate - Google Patents

Abstract

PURPOSE:To obtain a superior element by sticking a semitransmission type reflecting plate formed by laminating a foamed resin film and a light transmitting film to the rear of a liq. crystal display element to improve the transmitting and reflecting characteristics and to compensate the scratchability of the foamed resin with the light transmitting film. CONSTITUTION:A urethane modified acrylic resin adhesive 11 soluble in a solvent is coated on a light transmitting film 10 such as a polyester film, and it is dried. A foamed polypropylene film 12 is dry-laminated on the surface of the adhesive 11, and the adhesive 11 is cured to form a semitransmission type reflecting plate 13. This plate 13 is stuck to a polarizing plate 5b by dry-laminating the film 10 on an adhesive 6 coated on the plate 5b and dried. The surface of the plate 13 is hardly scratched, and high work efficiency is attained. The reflecting plate 13 having the stuck polarizing plate 5b is stuck to a substrate 2b of a liq. crystal display element by means of a roll 14. The plate 13 having superior optical properties acts as a reflecting plate in a light place and acts as a light transmitting plate in a dark place, so a clear display is obtd.

Description

Detailed Description of the Invention This relates to the configuration of a hyper-reflective plate, in which polarizing plates are arranged on the outer surface of the element with their polarization axes perpendicular to each other at 90 degrees, and the polarizing plates are arranged on the outer surface of the element with their polarizing axes perpendicular to each other at 90 degrees, and the reflective plate is placed on the opposite surface corresponding to the pattern display surface. A semi-transparent spiral reflector having both transparency and transparency functions is disposed, and a light source is disposed on the back side of the semi-transparent spiral reflector.

The semi-transparent spiral reflector used in such a configuration is
A thin layer of A/ is deposited on a polyester film.

A method of pasting this onto a polarizing plate, a method of applying an adhesive mixed with aluminum powder onto a polyester film, and a method of pasting this onto a polarizing plate, a method of applying an adhesive or a pressure-sensitive adhesive mixed with mica powder, etc. If the device is attached to the back of a liquid crystal display element, it can be used as a reflective liquid crystal display device during the daytime, and as a transmissive liquid crystal display device at night when the light source is turned on. Therefore, the semi-transparent spiral reflector is required to have excellent reflection characteristics and excellent transparency. On the other hand, reflection characteristics and transmission characteristics are contradictory phenomena, and in conventional semi-transparent spiral reflectors, hI! is coated on a polyester film in order to achieve both.
Both were achieved by changing the amount of ladle powder and the thickness of the deposited film.

On the other hand, the foamed resin 9 is, for example, foamed polypropylene.

Expanded styrene or urethane foam, etc., have gas inside, so when comparing the same film thickness.

Excellent light transmittance. Another advantage is that by reducing the diameter of the bubbles in this foamed resin, the reflectance can be improved.

However, although such foamed resin has excellent optical properties, it has not been put into practical use due to problems such as its structure being easily damaged and difficult to link. The current situation is that this is not the case.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its objectives are as follows.

It is an object of the present invention to provide a liquid crystal display device equipped with an optically excellent semi-transparent spiral reflector that has improved both reflection characteristics and transmission characteristics.

[Summary of the invention]

In order to achieve such an object, the present invention comprises a semi-transparent spiral reflector made of foamed resin and a transparent film.

[Embodiments of the invention]

Next, the present invention will be explained in detail using the drawings.

The basic configuration of a transflector type liquid crystal display device is generally
As shown in the figure, predetermined segment electrodes 1a are made of tin oxide or tin oxide and indium oxide on a transparent substrate such as glass.
, a pair of upper and lower electrode substrates 2* on which the common electrode 1b is formed.
+2b are arranged facing each other at a predetermined interval, the periphery is sealed with a sealing material 3, a liquid crystal material 4 is sealed in the space between them, and furthermore, polarizing plates 5 are placed on the front and back surfaces of the lower electrode substrates 2a and 2b.
a, 5b, a semi-transparent spiral reflector T is disposed on the back surface of the lower electrode substrate 2b via an adhesive 6, and a light source 8 is further disposed on the back of the semi-transparent spiral reflector T. As shown in Fig. 2, the polarizing plates 5m and 5b shown in Fig. 1 are omitted, and a system in which a dichroic dye is added to the liquid crystal material 4 is used, and a third
As shown in the figure, a polarizing plate 5 is provided only on the back side of the lower electrode substrate 2b.
There is one using b. In such a configuration, above,
By applying a predetermined voltage between the segment electrode 1a and the common electrode 1b formed on the opposing surfaces of the lower electrode substrates 2m and 2b.

The liquid crystal molecules of the liquid crystal material 4 or the dichroic dye attached thereto cause an electro-optical change, and a desired pattern is displayed.

The stone semi-transmissive reflector T used in such a configuration is formed by lining a foamed resin film with a particle size of approximately 2 μm with a resin film with excellent translucency, such as polyester, acrylic, acetate, or polycarbonate film. It can be made of foamed resin. As a method for manufacturing this semi-transparent spiral reflector 1, for example, when integrating it with the lower polarizing plate 5b, a foamed resin 7a is fixed to the polarizing plate 5b with adhesive 6 as shown in FIG. Then, it may be formed by lining with a translucent resin film 7b, or the foamed resin 7a may be fixed on the translucent resin film Tb with an adhesive 6, and then adhered to the polarizing plate 5b. Fixing with agent 6 is more advantageous in terms of work. In this way, the transparent resin film 7
If a method of adhesively fixing the foamed resin 7a to the substrate 7a is used, it becomes extremely easy to attach the liquid crystal display element to the lower electrode substrate 2b as shown in FIG.

This will be explained below using a specific example.

Specific Example First, as shown in FIG. 5, a urethane-modified acrylic resin solvent-based adhesive 11 is applied onto a polyester film 10 having a thickness of approximately 25 μm, and the solvent is dried. Next, a foamed polypropylene film 12 having a thickness of about 20 μm S degree is laminated onto the upper surface of the adhesive 11 through a dry laminator, and the adhesive 11 is cured to complete the semi-transparent elbow board 13. In this case, the reflective performance of the foamed polypropylene film 120 deteriorates when the temperature at the time of adhesion is about 80°C or higher, so
The sides are pasted together using adhesive 6 using a dry laminator to complete the process. The semi-transparent spiral reflector 13 manufactured in this manner is resistant to surface scratches.

It was easy to work with and had excellent optical properties. Next, when attaching the semi-transparent spiral reflector 13 to which the polarizing plate 5b is attached to the back surface of the liquid crystal display element, roller attachment is performed using a roller 14 as shown in FIG. 6, which is conventionally done. It was found that the adhesive could be pasted without any scratches, cracks, etc., even after this process. It has been found that the semi-transparent reflector without the polyester film 12 described above is easily damaged during handling. In addition, in a system in which an eye protection film was used as a substitute for the transparent resin to protect the foamed resin, it could not be used because it was easily scratched after the protective film was peeled off.

FIG. 7 shows data showing the relationship between the transmittance and reflectance of semi-transparent spiral reflectors with polarizing plates according to the prior art and the present invention. In the same figure, a combination of a semi-transparent reflector plate made of a conventional polyethylene terephthalate film coated with aluminum powder or an aluminum vapor-deposited film and a polarizing plate with a light polarization rate of about 48% is marked with a dot AOO. As shown in the figure, a transmittance of only about 0.15% and a reflectance of about 14'1 were obtained. On the other hand, in the combination of the semi-transparent reflector according to the embodiment of the present invention and the conventional polarizing plate,
When combined with a polarizing plate having a polarization rate of about 40%, the transmittance is about 0.3g6., as shown by the Q mark at point B in the figure. In combination with a polarizing plate with a reflectance of about 12% and a polarization factor of about 45 degrees, the transmittance is about 0.5% and the reflectance is about 12.8, as shown by the Q mark at point C in the same figure. %, and in combination with a polarizing plate having a polarization factor of about 48 inches, the transmittance is about 0.7% and the reflectance is about 14.3%, as shown by the dots in the same figure. As shown, the distribution was possible within region E (transmittance: 0.5±3%, reflectance: 13±2%), which was excellent in both transmission and reflection characteristics.

〔Effect of the invention〕

As explained above, according to the present invention, by configuring the semi-transparent reflector with a foamed resin material and a translucent film, it is possible to improve both the transmission characteristics and the reflection characteristics. This has an extremely excellent effect in that a transmissive-reflector type liquid crystal display device can be obtained.

[Brief explanation of the drawing]

1 to 3 are cross-sectional configuration diagrams of main parts showing a transflective plate type liquid crystal display device according to the present invention, and Fig. 4 is an enlarged cross-sectional view of main parts showing an example of a semi-transparent reflector plate according to the present invention. FIG. 5 is a sectional view of a main part showing a specific example of a semi-transparent reflector according to the present invention;
FIG. 6 is a cross-sectional view of essential parts showing a method of bonding an assembly of a semi-transparent reflector and a polarizing plate according to the present invention to a liquid crystal display element, and FIG. FIG. 3 is a data diagram showing the relationship between transmittance and reflectance of a shaped reflector. 1a...Segment'! Pole, lb...Common electrode, 2a...Upper electrode substrate, 2b...Lower electrode substrate, 3...Seal removal, 4...Liquid crystal material, 5a,
5b...Polarizing plate, 6...Adhesive, 7...Anti-transmission reflector, 8...Optical i, io...Polyester film, 11e...Adhesive, 12... Foamed polypropylene film, 13... Semi-transparent reflector, 14... Roller. Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claim] A liquid crystal display device comprising a semi-transparent spiral reflector on the back surface of a liquid crystal display element, the semi-transparent spiral reflector. A transflective plate-type liquid crystal display device comprising a foamed resin and a translucent film.