JPS60100171A - Liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a liquid crystal display device, and particularly to a plastic liquid crystal display device in which an electrode substrate and a q-polarizing plate are made of the same material.

[Background of the invention]

2. Description of the Related Art In recent years, a plastic liquid crystal display element has been proposed in a liquid crystal display device in which an envelope in which liquid crystal is sealed is formed of a translucent plastic film substrate instead of a conventional glass substrate. The plastic liquid crystal display element is constructed by interposing a liquid crystal between two plastic film substrates with electrodes formed on opposing surfaces, and sealing the periphery with a sealing material. In particular, in the case of twisted nematic type display (hereinafter referred to as TN display) liquid crystal display devices, by pasting a polarizing plate on the outer surface of the film substrate, a transmission type display device can be used. A reflective display device is constructed by laminating a polarizing plate on the upper plate side and a polarizing plate and a reflecting plate on the lower plate side.

The liquid crystal display device configured in this way is shown in FIG.
) As shown in (b), transparent upper and lower electrodes 3 and 4 are formed on the opposing surfaces of upper and lower substrates 1 and 20 made of transparent plastic films, respectively, and the upper and lower electrodes 3 and 4 are respectively adhered thereto.

The liquid crystal 1 is sealed in an envelope 6 formed by arranging the lower substrates 1 and 2 to face each other with a sealing material 5 containing a spacer interposed therebetween to form a liquid crystal display element. , upper and lower polarizing plates 8 and 9 are adhesively arranged on the outer surfaces of the lower substrates 1 and 2, respectively, and the optical properties of the liquid crystal between the upper and lower electrodes 3 and 4 are changed, and this change is applied to the outer surface of the lower polarizing plate 9. Light reflecting plate 10
t-position and can be recognized from the upper polarizing plate 8 side.

However, in a plastic liquid crystal display device constructed in this way, the upper and lower polarizing plates 8 and 9 are easy to process into a film shape and have excellent optical properties such as light transmittance. As shown, a polarizer 11 has a three-layer, nine-layer structure sandwiched between an organic film 12 such as an acrylic resin or cellulose triacetate as a support. - The electrode substrates 1 and 2 are required to have chemical resistance against heating conditions during the device manufacturing process, liquid crystal materials, etching liquids, etc., but the organic film 12 described above does not satisfy the heat resistance or chemical resistance. Therefore, an axisless polyether sulfone or a -axially stretched polyester film is used. Therefore, each electrode substrate 1, 2 and each polarizing plate 8 made of the above-mentioned material.
, 9 are bonded and arranged, since their linear expansion coefficients or thermal contraction coefficients are different, stress is generated in the bonded portion of the two when heated, causing warping in the liquid crystal display element, resulting in poor display quality and reliability. There was a problem with the total drop.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a liquid crystal display device in which the expansion coefficients or thermal contraction coefficients of the electrode substrate and the polarizing plate are completely matched, and display quality and reliability are improved.

[Summary of the invention]

In order to achieve such an object, the present invention comprises an electrode substrate and a support film of a polarizing plate made of the same material.

[Embodiments of the invention]

Next, embodiments of the invention will be described in detail with reference to the drawings.

FIG. 3 is a cross-sectional configuration diagram of essential parts showing an example of a liquid crystal display device according to the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

In the same figure, the upper and lower substrates 1' and 2' have a thickness of approximately 100 μm.
Using a non-axially stretched polyether sulfone film of
Upper and lower electrodes 3 and 4 were formed thereon, and polyetheramide resin was used for the alignment film. Furthermore, upper and lower substrates 1 and 2
' is adhered to the polyester sealing material 5' to form an envelope 6, the liquid crystal T is completely enclosed and sealed in this envelope 6, and the outer surfaces of the upper and lower substrates 1 and 2 are further sealed. Upper and lower polarizing plates 8° 9 with polyether sulfone film as a support,
The entire liquid crystal display device was constructed by laminating them together so that the absorption axes were perpendicular to each other at the bottom. - As a comparative example, an envelope 6 was formed with the same configuration as the example, liquid crystal 1 was enclosed and sealed, and a polarizing plate using acrylic resin f as a support was bonded to the polarizing plate. Liquid crystal display devices with different cellulose materials were manufactured. As a result of leaving these two types of liquid crystal display devices in a high temperature environment of about 70°C for about 100 hours, the liquid crystal display devices obtained according to the embodiments of the present invention were less than about 0.5 m in device size of 15 x 40 + m. In the liquid crystal display device obtained in the comparative example, an amount of warpage of about 1 degree occurred compared to the amount of warpage of . Incidentally, the amount of the liquid crystal display device Rf: When placed on a certain plane, the maximum distance that the liquid crystal display device separates from the plane is defined as the total distance. Therefore, by forming the upper and lower substrates 1 and 2 and the upper and lower polarizing plates 8' and 9' from the same material of polyether film, it is possible to significantly suppress the anti-shading of the liquid crystal display device. I can do it.

In addition, as another embodiment of the present invention, when a uniaxially stretched polyethylene terephthalate (hereinafter abbreviated as PET) film made of the same material is used for the substrate and the polarizing plate, the -axis stretched PET film is Since the coefficient of thermal expansion or thermal contraction is different between the two, when the two are bonded together, the display on the liquid crystal display becomes darker as the combination of angles in each stretching direction becomes larger, and the bonded portion becomes darker. Warping will occur due to distortion caused by heat. Therefore, when using a uniaxially stretched PET film for the substrate and the polarizing plate, by bonding them together with the stretching direction of the two aligned, it is possible to carry out the same high-temperature environment test as described above and
In a life test of approximately 1,000 hours in a concave environment at 954 RH and 954°C, the overall warpage of a liquid crystal display device of the same device size was suppressed to 0.3 or less.

In yet another embodiment of the present invention, even if the entire reflector board is made of the same material, the amount of warping is 0.3 mm with the same device size in the high-temperature environment test and life test described above.
I was able to keep it below.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reduce the warpage of a liquid crystal display device, and therefore, the extremely excellent effect of greatly improving display quality and reliability can be obtained.

[Brief explanation of the drawing]

Figures 1(a) and 1(b) are perspective views showing an example of a conventional liquid crystal display device, and a cross-sectional configuration diagram of the main parts thereof. Figure 2 is a perspective view of the main parts showing the structure of a polarizing plate. Figure 3 is an omitted diagram. 1 is a cross-sectional configuration diagram of main parts showing an example of a liquid crystal display device according to the invention. 1'... Upper substrate, 2... Lower substrate, 3... Upper electrode, 4... Lower electrode, 5... Seal material, 6'...
...Envelope, 7...Liquid crystal, 8'...Upper polarizing plate, 9'...Lower polarizing plate, 10...Reflecting plate.

Claims (1)

[Scope of Claims] 1. A liquid crystal display element formed by sandwiching a liquid crystal between plastic substrates with transparent electrodes formed on the inner surface and sealing the periphery with a sealant, and an adhesive bonded to the outer surface of the liquid crystal display element. In a liquid crystal display device comprising a polarizing plate and a reflecting plate adhesively arranged on one outer surface of the polarizing plate, at least one of the polarizing plate and the reflecting plate is the same as the support film of the substrate. A liquid crystal display device characterized by being formed from a material. 2. The liquid crystal display device according to claim 1, characterized in that the substrate and the polarizing plate are formed of uniaxially stretched glass films, and their stretching directions are the same.