JPH10206633A - Polarizing plate and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate in such a form that the polarizing layer is not exposed to the outside. SOLUTION: In a polarizing plate having a polarizing layer 1 held by a pair of protective layers 2 and 3 between them, the end parts of the protective layers 2, 3 laminated on both sides of the polarizing layer 1 are formed and joined so as to cover the polarizing layer 1 in its outside peripheries. The polarizing layer 1 is covered by the protective layers 2, 3 by the joining at the end parts of the protective layers 2, 3. The polarizing plate is manufactured in such a way that a polarizing sheet material larger than a desired size is cut by a heated cutting tool after it has been suited to a desired size and to a desired direction of the transmitting axis of light, and the end parts 2a of the protective layer 2 are deformed by a load and heat, so that the peripheral part of the polarizing layer 1 is covered and joined with the protective layer 3, and the polarizing layer 1 is covered by the pair of protective layers 2, 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polarizing plate,
In particular, the present invention relates to a polarizing plate used for a liquid crystal element and a method for manufacturing the same.

[0002]

2. Description of the Related Art A polarizing plate is formed by adsorbing iodine or a dye after orienting a resin such as polyvinyl alcohol, and transmitting one of orthogonal polarization components of light.
It is composed of a polarizing layer that absorbs the other, and a protective layer made of a resin such as cellulose acetate laminated so as to sandwich the polarizing layer.

The polarizing plate is used for a liquid crystal element. In this case, an adhesive layer is formed by laminating an adhesive layer on one of the protective layers on the side opposite to the polarizing layer. It is used by being bonded to a substrate of a liquid crystal element by an agent layer.

Heretofore, the above-mentioned polarizing plate has been manufactured by using a polarizing sheet material having a size larger than a desired shape having a polarizing layer and a pair of protective layers sandwiching the polarizing layer to a size required for a liquid crystal element to be used. Of the components (hereinafter referred to as a transmission axis).

[0005]

In order to obtain a polarizing plate having a desired shape and a transmission axis from a large-sized polarizing sheet material, the polarizing sheet material is cut by a cutting tool having a sharp blade. Therefore, a state in which the polarizing layer is exposed to the outside on the cut surface occurs.

[0006] From the exposed portion of the polarizing layer, a change with time occurs due to the influence of moisture absorption, light and heat, which causes separation of the interface between the polarizing layer and the protective layer, generation of bubbles and cracks, and the like.
This causes deterioration of the performance as a polarizing plate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polarizing plate having improved reliability of the polarizing plate by preventing separation at the interface between the protective layer and the polarizing layer, a change with time such as moisture absorption and photothermal change.

[0008]

According to the present invention, in order to achieve the above object, a polarizing layer which transmits one of orthogonal polarization components of light and absorbs the other is sandwiched between the polarizing layer and the polarizing layer. In a polarizing plate having a pair of protective layers disposed at positions and protecting the polarizing layer, the pair of protective layers are bonded to each other at an edge of the polarizing layer.

Further, the polarizing plate is manufactured by a method of cutting a polarizing sheet material having a shape larger than a desired shape, in which a polarizing layer and a pair of protective layers sandwiching the polarizing layer are laminated, with a heated cutting tool. Manufactured.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polarizing plate of the present invention does not expose a polarizing layer sandwiched between a pair of protective layers around the polarizing plate.
It is formed by joining a pair of protective layers at the edge of the polarizing layer. In addition, the polarizing plate of the present invention is obtained by heating a polarizing sheet material having a desired size and a transmission axis larger than a desired shape having a polarizing layer and a pair of protective layers sandwiching the polarizing layer. Cut with the cutting tool
It is manufactured by a method of joining the pair of protective layers to each other at the edge of the polarizing layer by the pressure and heat at the time of cutting.

In the polarizing plate thus constructed, since the periphery of the polarizing layer is not exposed, the polarizing plate is unlikely to change with time due to the influence of moisture, heat or light entering from outside. Therefore, the reliability of the liquid crystal display device can be enhanced by using the polarizing plate in a liquid crystal display device product or the like.

[0012]

Embodiments will be described with reference to the drawings.
As shown in FIG. 1, the polarizing plate has a polarizing layer 1 having a thickness of several μm to several tens μm formed by orienting a resin such as polyvinyl alcohol and adsorbing iodine and the like. It comprises a pair of protective layers 2 and 3 each having a thickness of several hundred μm and made of a thermoplastic resin such as cellulose acetate and arranged on the surface with the polarizing layer 1 interposed therebetween.

The outer periphery of the polarizing plate is formed such that the end 2a of the protective layer 2 laminated on both surfaces of the above-mentioned polarizing layer 1 covers the polarizing layer 1 and is joined to the protective layer 3. By joining the protective layers 2 and 3 around the outer periphery of the polarizing plate, the polarizing layer 1 is formed.
Has a structure that is not exposed to the outside.

On one surface of the protective layer 3 on the side opposite to the polarizing layer 1, there is provided an adhesive layer 4 for bonding to the substrate, and on the opposite side of the protective layer 2 from the polarizing layer 1. A surface protective film 5 for protecting the polarizing plate is adhered to the surface so as to be peelable.

The polarizing plate of this embodiment is manufactured by the manufacturing method shown in FIG. FIG. 2A shows that the cutting tool 7 has come into contact with the polarizing sheet material 6 having a polarizing layer 1 and a pair of protective layers 2 and 3 sandwiching the polarizing layer 1 and having a shape larger than a desired shape. FIG. 2B shows a state in which the cutting has been completed.

The polarizing plate is cut by the cutting tool 7 such as a metal or ceramic wheel at a position indicated by a dashed line in the drawing. The cutting tool 7 is heated in advance to a temperature higher than the thermal deformation temperature (preferably, melting temperature) of the pair of protective layers 2 and 3 used for the polarizing sheet material 6 and moves while applying a load to the polarizing sheet material 6 surface. Then, the polarizing sheet material 6 is cut.

At this time, the protective layer 2 is easily deformed by the heat of the cutting tool 7, and is subjected to a force by the cutting tool 7, so that the protective layer 2 is cut and thermally deformed, and the end 2a of the polarizing layer 1 is removed. The cut edge 1a is covered and reaches the protective layer 3, and the thermally deformed protective layer 2 is joined to the protective layer 3. Therefore, the edge 1 a of the polarizing layer 1 is covered with the protective layer 2 and the protective layer 3.

[0018]

According to the present invention as described above, since the protective layer which narrows the polarizing layer covers the edge of the polarizing layer, it is possible to provide a polarizing plate in which the polarizing layer is not exposed to the outside. .

In the polarizing plate of the present invention, since the entire periphery of the polarizing layer is covered with the protective layer, peeling at the interface between the polarizing layer and the protective layer, bubbles, Cracking can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a polarizing plate according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a method of manufacturing a polarizing plate according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polarization layer 2 Protective layer 3 Protective layer 4 Adhesive layer 5 Surface protective film 6 Polarizing sheet material 7 Cutting tool

Claims (2)

[Claims] 1. A polarizing layer that transmits one component of orthogonal polarization components of light and absorbs the other component, and a pair of protective layers disposed at positions sandwiching the polarizing layer and protecting the polarizing layer. A polarizing plate, comprising: a pair of protective layers joined to each other at an edge of the polarizing layer. 2. The polarizing plate is formed by cutting a polarizing sheet material having a shape larger than a desired shape having a polarizing layer and a pair of protective layers sandwiching the polarizing layer with a heated cutting tool. The method for manufacturing a polarizing plate according to claim 1, wherein: