JPS6374031A - Liquid crystal display body - Google Patents

Abstract

PURPOSE:To obtain the titled device capable of preventing decrease of transparency of a transparent plastic plate by integrating a polarizing film and the transparent plastic plate with a saturated co-polyester film in between, thereby preventing whitening of the transparent plastic plate. CONSTITUTION:The upper polarizing plate 1 is overlaid on a liquid crystal cell 2, and the transparent plastic plate 3 is overlaid on the upper polarizing plate 1. And, the lower polarizing plate 1' is overlaid on the lower part of the liquid crystal cell 2. The polarizing film 10 for the upper polarizing plate 1 is integrated with the transparent plastic plate 3 by interposing the saturated co-polyester film 11 between-them. The polarizing film 10 and the liquid crystal cell 2 are sticked with each other by a pressure sensitive adhesive layer 12. The liquid crystal cell 2 is constituted by a glass plates 20 for the liquid crystal cell and the liquid crystal 21 contained between the glass plates 20. Thus, the decrease of transparency of the transparent plastic plate 3 due to whitening is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal display with excellent dual display performance and high strength.

(Prior Art) Liquid crystal displays are generally manufactured by providing a pressure-sensitive adhesive layer on a polarizing film and press-bonding this to a liquid crystal cell. For example, the polarizing film is 9.

It is formed by laminating both sides of a polyvinyl alcohol film, etc., which has been imparted with polarizing properties with iodine, dichroic dye, etc., with a protective film, such as a cellulose triacetate film.

In recent years, as liquid crystal displays have become larger, protective glass with anti-reflection treatment (AI? glass) and transparent plastic plates (such as acrylic) have been used to protect polarizing films and improve visibility during use. A protective plate such as a polycarbonate plate is provided on the polarizing film. However, there is a gap between the protective plate and the polarizing film, which makes the liquid crystal display easily damaged. Moreover, these voids are the cause of making the layer 7 of the liquid crystal display thick.

Because of this, we have created a resin film J4 between the polarizing film and the protective plate while eliminating gaps and making the liquid crystal display thinner.
Attempts are being made to establish a As a result, the liquid crystal display can be made thinner, and damage to the liquid crystal display caused by voids can be avoided. As the resin film, adhesive thermoplastic resin films such as plasticized polyvinyl butyral have been proposed. This improves the strength of the liquid crystal display.

However, when a transparent plastic temporary protective plate is used to reduce the weight of a liquid crystal display, the transparent plastic plate deteriorates due to bleeding of the plasticizer contained in the polyvinyl butyral film.

The surface has turned white due to the deterioration of the transparent plastic plate.

Transparency decreases, and the display performance of the liquid crystal display is impaired.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to provide a liquid crystal display with excellent display performance without reducing the transparency of the transparent plastic. It's about offering your body. Another object of the invention is.

An object of the present invention is to provide a lightweight and strong liquid crystal display.

(Means for Solving the Problems) The present invention aims to eliminate the gap between the polarizing film and the protective plate of a liquid crystal display (using saturated copolymer polyester instead of polyvinyl butyral, which was conventionally used). By doing so, even if a transparent plastic plate is used as a protective plate, there is no risk that the transparency of the transparent plastic plate will decrease.

Therefore, a liquid crystal display with excellent dual display performance can be obtained.

It was completed based on the inventor's knowledge.

The liquid crystal display of the present invention is a liquid crystal display in which a liquid crystal cell, a polarizing film, and a transparent plastic temporary layer are laminated, and the polarizing film and the transparent plastic plate are integrated with a saturated copolymerized polyester film. Thus, the above objective is achieved.

The saturated copolymerized polyester used in the present invention is a linear saturated copolymerized polyester consisting of at least one type of polycarboxylic acid and at least one type of polyhydric alcohol. As a polyhydric carboxylic acid.

Examples include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and diphenyldicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid, sepathic acid, and dodecanedicarboxylic acid. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,4. - Glycols such as butanediol and triethylene glycol can be mentioned. By appropriately selecting these seven units and randomly copolymerizing them by a conventional method, the thermal properties and physical and mechanical properties of the polyester resin can be adjusted as desired. As the saturated copolymerized polyester, a resin having a softening point (ring and ball method, JISL2531) of 140°C or lower, preferably 120°C or lower is used. When the softening point exceeds 140°C.

When integrating the polarizing film and the transparent plastic plate, it is necessary to heat the film to a high temperature.

Polarizing film deteriorates due to heat. Adhesion between the saturated copolymerized polyester film and the polarizing film and transparent plastic plate is also difficult to obtain.

The saturated copolymerized polyester film contains UV absorbers,
Antioxidants, colorants, adhesion modifiers such as metal salts of carboxylic acids, and the like may also be contained.

In particular, when an ultraviolet absorber is blended, harmful ultraviolet rays are blocked for polarizing films and liquid crystals, thereby improving weather resistance.

For example, acrylic board for transparent plastic board.

There is a polycarbonate board.

The polarizing film is not particularly limited, and any conventionally known film can be used. This is applied to one or both sides of a polarizing film that has been given polarizing properties.

Three sides. Cellulose-based films such as acid cellulose.

It is obtained by laminating protective films such as polycarbonate films and polyethersulfone films. The polarizing film is made of a polyvinyl alcohol resin such as polyvinyl alcohol, polyvinyl polymer, polyvinyl acecool, or a genated product of ethylene-vinyl acetate copolymer.

It is produced by impregnating it with a polarizing element such as iodine or dichroic dye and stretching it.

The liquid crystal display of the present invention is formed, for example, in a linear manner.

A polarizing film is laminated onto the liquid crystal cell using, for example, a pressure-sensitive adhesive. A saturated copolymerized polyester film is placed on this polarizing film, and a transparent plastic plate is further placed on top of it. This structure is placed in an airtight body such as a rubber bag, and degassed under reduced pressure to 650 m m tl g or less at a temperature of 50° C. or lower, preferably 30° C. or lower.

The degassing time is preferably 5 minutes or more. Next, the rubber bag containing the structure is placed in a heating furnace such as a gear oven, and heated for 6 hours.
Heat to 0-140°C, preferably 65-85°C. It is preferable to continue degassing during heating. The rubber bag is taken out of the heating furnace, and after cooling to below 50°C, the construction is taken out. This construct weighs 3 kg in an autoclave.
The temperature is generally 60 to 140°C, preferably 65 to 85°C, at a pressure of /ad or higher. In this case, the structure may be pressurized and heated without being removed from the rubber bag.

In this way, a transparent plastic plate is further laminated on the laminate of the liquid crystal cell and the polarizing film with the saturated copolymerized polyester film interposed therebetween.

Note: 1. When manufacturing the liquid crystal display of the present invention.

It is preferable to form a large number of irregularities on one side of the saturated copolymerized polyester film in advance so that the film can be sufficiently coated when laminated onto a temporary transparent plastic.

The unevenness may be provided on both sides of the film, but in that case, the dimensional accuracy of the liquid crystal display decreases. It is preferable that the average spacing between adjacent recesses or adjacent protrusions be approximately twice or more than the 10-point average roughness in order to improve deaeration performance, and approximately 10 times or less is preferable. This is preferable in that the adhesiveness can be reduced when a highly adhesive resin is used. The average interval between the two irregularities is usually 100 to 500 μm, preferably 200 to 300 μm. The 10-point average roughness is usually 20 to 100 μm.

Preferably it is 25 to 70 μm. At 25 μm or less.

When a transparent plastic plate is laminated on a polarizing film, the sealing at the periphery occurs first, resulting in insufficient degassing at the center. Therefore, the transparent plastic plate 5 becomes opaque. Since there is a large amount of residual air even with a diameter of 70 μm or more, foaming occurs during heat and moisture resistance tests. Here, the 10-point average roughness means Rz measured in accordance with 15O-R468. To form irregularities on a saturated copolymerized polyester film, for example, an embossing roll method or a calender roll method is used.

Methods include profile extrusion, mechanical etching, and a method using male and female press plates, with the embossing roll method being particularly preferred. The embossing roll method uses an embossing roll that has concavities and convexities that correspond to the concavities and convexities to be imparted to the surface of the saturated copolyester film.

This method is used as a forming press roll in the production of resin films.

Further, the polarizing film may be provided with a saturated copolymerized polyester film on one side in advance.

Furthermore, a pressure-sensitive adhesive layer may be provided on the opposite surface. For example, this pressure-sensitive adhesive layer has one.

Acrylic resin such as acrylic acid (2-ethylhexyl)-methacrylic acid copolymer is used.

The outer surface of the pressure sensitive adhesive layer is smooth. By doing so, distortion of the liquid crystal cell is reduced. Furthermore, in the lamination of the pressure-sensitive adhesive layer and the liquid crystal cell, sufficient deaeration can be achieved even if the outer surface of the pressure-sensitive adhesive layer is smooth.

The liquid crystal display of the present invention has a structure such as, for example, as shown in FIG.
An upper polarizing plate 1 is laminated on a liquid crystal cell 2, a transparent plastic plate 3 is further provided on the upper polarizing plate 1, and a lower polarizing plate l° is laminated below the liquid crystal cell 2. The polarizing film 10 of the upper polarizing plate 1 is integrated with the transparent plastic plate 3 through a saturated copolymerized polyester film 11.

The polarizing film 10 and the liquid crystal cell 2 have a pressure-sensitive adhesive layer 12
It is glued with. The liquid crystal cell 2 is glass 2 for liquid crystal cells.
0 and a liquid crystal 21 housed within a glass 20.

(Example) The present invention will be described below with reference to examples.

sword punishment soup Plate-shaped saturated copolymer polyester (softening point 105°C.

Byron 560. (manufactured by Toyobo Co., Ltd.), 70'c, 5
0, press was performed using a male and female press plate under the conditions of X/c++1.

A saturated copolymer polyester film 1 with a thickness of 380 μm and having a mirror surface on one side and unevenness on the other side was prepared. The unevenness is I
SO・Rz was 45 μm.

The lower polarizing plate, liquid crystal cell, and polarizing film were laminated using a pressure-sensitive adhesive made of acrylic acid (2-ethylhexyl)-methacrylic acid copolymer containing polyisocyanate (triepoxypropyl isocyanate) as a crosslinking agent. The above saturated copolymerized polyester film was placed on this laminate. Furthermore, an acrylic plate (2mm thick, 1
00mm x 250mm.

Mitsubishi Acrylite (manufactured by Mitsubishi Rayon Co., Ltd.) was placed thereon to form a structure. As a polarizing film.

Cellulose triacetate/polyvinyl alcohol/cellulose triacetate (H 180 μm
) was used. An aluminum foil was provided below the lower polarizing plate as a reflective plate.

The thus obtained construct was placed in a rubber bag at room temperature (20°C), T: 700 mm, 1 g or less, or 710
Degassed under reduced pressure for a minute. The rubber bag was then heated in a gear oven for 30 minutes with degassing to a surface temperature of 70"C (pre-pressing). The rubber bag was then placed in a pneumatic autoclave and heated at a pressure of 5 kg/cnl for 7 min.
The saturated copolymerized polyester film was adhered to the acrylic plate by heating to 0°C (main press). The maximum temperature was held for 20 minutes. The saturated copolymerized polyester film and the acrylic plate were sufficiently degassed, and no air bubbles remained in the resulting liquid crystal display.

The liquid crystal display thus obtained had excellent transparency, and no phenomena such as whitening of the acrylic plate were observed. Using this liquid crystal display as a sample, a moisture resistance test (6
0°C, 90% R011, 500 hours) heat resistance test (8
0°C for 500 hours). As a result, the polarizing plate did not peel off not only at the center of the sample but also at the periphery, and no abnormalities such as bubbles or wrinkles were observed.

Implementation ±1 A saturated copolymerized polyester film with unevenness formed on both sides was used, and a polycarbonate plate (2ua thickness, 100++n x 250mm, 2ua thickness, 100++n x 250mm,
A liquid crystal display was obtained in the same manner as in Example 1, except that L-Pironcy-1., manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used.

The obtained liquid crystal display had excellent transparency, and no phenomenon such as whitening of the polycarbonate plate was observed. When this liquid crystal display was subjected to a moisture resistance test and a heat resistance test in the same manner as in Example 1, no abnormalities such as peeling of the polarizing plate, bubbles, or wrinkles were observed.

Polyvinyl butyral resin (average degree of polymerization 1700°, degree of butyralization 65 mol%, residual vinyl alcohol 34.5
A polyvinyl butyral composition was prepared by mixing 40 parts by weight of triethylene glycol di-2-ethyl butyrate with 100 parts by weight (mol%).

After kneading this composition with a roll at 70°C.

150℃, 50kg/cn! Male R1 under the conditions of
Pressing was performed using a 1L type press plate to obtain a plasticized polyvinyl butyral film having a thickness of 380 μm and having unevenness formed on two surfaces. The unevenness had a 10-point average roughness of 35 μm.

This plasticized polyvinyl butyral film was used instead of the saturated copolymerized polyester film.

A structure was formed by the same method as in Example 1.

This structure was subjected to preliminary pressing and main pressing in the same manner as in Example 1 to obtain a liquid crystal display. but.

The acrylic plate of the obtained liquid crystal display had turned white.

It lacked transparency.

Kitasamekan I Polycarbonate of Example 2 instead of acrylic plate, -h +
A liquid crystal display was obtained in the same manner as in Comparative Example 1 except that H was used. However, the obtained liquid crystal display had a whitened polycarbonate plate and lacked transparency.

As is clear from the Examples and Comparative Examples, the liquid crystal display of the present invention has a saturated copolymer polyester film disposed between the polarizing film and the transparent plastic plate, so that the transparent plastic plate becomes white and becomes transparent. There is no decline in sexuality. In conventional liquid crystal displays, the transparent plastic plate becomes white due to bleeding of the plasticizer in the plasticized polyvinyl butyral film disposed between the polarizing film and the transparent plastic plate. Therefore, the transparency of the transparent plastic plate is reduced, and the display performance of the liquid crystal display is impaired.

(Effects of the Invention) The liquid crystal display of the present invention is thus formed by integrating a polarizing film and a transparent plastic plate with a saturated copolymerized polyester film, so that the transparent plastic plate does not whiten as in the conventional case. Therefore, there is no risk of reducing its transparency. Therefore, a liquid crystal display with excellent display performance can be provided.

FIG. 1 is a sectional front view showing one embodiment of the liquid crystal display of the present invention.

1... Upper polarizing plate, 1''... Lower polarizing plate, 2... Liquid crystal cell.

3...Transparent plastic IX, 10...Polarizing film.

11... Saturated copolymerized polyester film, 12...
・Pressure sensitive adhesive layer, 20... Glass for liquid crystal cell, 21.
··liquid crystal.

that's all

Claims (1)

[Claims] 1. A liquid crystal display in which a liquid crystal cell, a polarizing film, and a transparent plastic plate are laminated, wherein the polarizing film and the transparent plastic plate are integrated with a saturated copolymerized polyester film. LCD display. 2. The liquid crystal display according to claim 1, wherein the transparent plastic plate is an acrylic plate. 3. The liquid crystal display according to claim 1, wherein the transparent plastic plate is a polycarbonate plate. 4. The liquid crystal display according to claim 1, wherein the saturated copolymerized polyester has a softening point of 140° C. or lower.