JPH0961626A - Polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate of the constitution to allow the mass production of a so-called non-reflection polarizing plate by a simple method capable of easily forming a transparent thin film layer as an antireflection layer on the surface of a polarizing plate, having a good adhesion degree of this transparent thin film layer and without hindering its polarization function. SOLUTION: This polarizing plate 1 is constituted by holding and laminating substrate base materials 1B for which TAC films are adopted on the front and rear surfaces of a polishing element 1A and is disposed on the front surface side to be visibly admitted of a liquid crystal display. The TAC film is not used for the surface base material 1B laminated on the front surface side to be visibly admitted of the polarizing plate 1 opposite to the liquid crystal display side and the transparent thin film layer 2A having the refractive index lower than the refractive index of the base material for forming is formed on the surface in place of the TAC film. At this time, the tight adhesion property of the transparent thin film layer 2A is better than the tight adhesion of the TAC and a transparent urethane film which does not hinder the polarization function of the polishing element 1a is used as the surface base material 1B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate which prevents surface reflection.

[0002]

2. Description of the Related Art Although a polarizing plate is always used on the surface of a liquid crystal display, a conventional simple polarizing plate has a surface reflection of about 4% on the surface thereof. In the inside outdoors, the surrounding scenery is remarkably reflected,
The display itself becomes difficult to see.

Therefore, conventionally, such surface reflection is suppressed,
In order to soften the apparent glare, it was attempted to mechanically make minute unevenness on the surface of the polarizing plate, or to form a layer with unevenness to deal with it. However, there is an adverse effect that the surface of the core itself is roughened instead of decreasing. Therefore, it is necessary to reduce the absolute reflectance (about 4% in the past) on the surface of the polarizing plate in order to reduce the reflection without the display roughness.

A method of reducing the reflectance of the surface can be realized by forming a thin film layer of a substance having a refractive index lower than that of the surface base material of the polarizing plate on the surface of the surface base material. However, a general polarizing plate uses triacetyl cellulose (TA
C) is widely used, and even if a known antireflection treatment such as forming a fluororesin film having a low refractive index is applied to the surface of the base material, the surface of the base material and the low refractive index thin film layer are sufficiently processed. Since adhesion is not obtained, it is not practical, and under the present circumstances, a hard coat layer is once formed by coating the surface of the surface substrate of the polarizing plate with an acrylic resin with good adhesion to this polarizing plate. Antireflection processing such as forming a low refractive index thin film layer on the hard coat layer formed on the surface of the plate is performed.

Therefore, it is necessary to once form a hard coat layer on an existing polarizing plate, and to apply antireflection processing to this polarizing plate, which is very difficult to manufacture and is not suitable for mass production, resulting in a high cost. Also, when coating this antireflection layer, if continuous coating is performed with heat,
In order to deteriorate the TAC of the surface substrate on the surface of the polarizing plate, it is necessary to use a vapor deposition method, and continuous coating cannot be performed on the polarizing plate. For example, an antireflection layer is continuously formed on the polarizing plate wound on a roll. It cannot be coated, resulting in poor mass productivity and high cost.

The present invention has found out such problems and
In order to solve this problem, trial production research was repeated, and after many years of research on polarizing plates, the surface substrate on the liquid crystal display side of the polarizing plate was T
It was found that AC is the most suitable, but the opposite side visible surface side surface base material does not significantly affect the polarization function even if the optical properties are inferior to the opposite side surface base material,
The present invention having a structure capable of easily performing favorable antireflection processing and providing an epoch-making non-reflective polarizing plate excellent in mass productivity was completed.

[0007]

The gist of the present invention will be described with reference to the accompanying drawings.

In a polarizing plate which is formed by sandwiching and laminating a surface base material 1B such as TAC on the front and back surfaces of the polarizing element 1A, and which is disposed on the visible surface side of the liquid crystal display body, the polarized light opposite to the liquid crystal display body side. The surface base material 1B laminated on the visible surface side of the plate 1 is not TAC, but instead of TAC, a transparent thin film layer 2A having a lower refractive index than the base material formed on the surface of urethane or the like is used as an antireflection layer on the surface. When applied, this transparent thin film layer 2A
And a transparent resin film which has better adhesion than TAC and does not hinder the polarization function of the polarizing element 1A as the surface base material 1B.

Further, a front surface substrate 1B using a TAC film is sandwiched and laminated on the front and back surfaces of the polarizing element 1A,
In the polarizing plate disposed on the visible surface side of the liquid crystal display body, the surface base material 1B laminated on the visible surface side of the polarizing plate 1 opposite to the liquid crystal display body side is not a TAC film, and T
When the transparent thin film layer 2A having a lower refractive index than the base material is applied to the surface instead of the AC film as an antireflection layer, the adhesiveness of the transparent thin film layer 2A is better than that of TAC, and The present invention relates to a polarizing plate characterized in that a transparent urethane film that does not hinder the polarizing function of the polarizing element 1A is used as the surface base material 1B.

Further, a front surface 1B using a TAC film is sandwiched and laminated on the front and back surfaces of the polarizing element 1A,
In the polarizing plate disposed on the visible surface side of the liquid crystal display body, the surface base material 1B laminated on the visible surface side of the polarizing plate 1 opposite to the liquid crystal display body side is not a TAC film, and T
A polarizing plate characterized in that a transparent urethane film having a transparent thin film layer 2A having a refractive index lower than that of a base material previously formed on the surface instead of the AC film as an antireflection layer is used as a surface base material 1B. Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention (how to carry out the invention) will be briefly described with reference to the drawings showing its function and effect.

When the polarizing plate 1 is manufactured, the surface base material 1B laminated on the visible surface side of the polarizing plate 1 opposite to the liquid crystal display side is not TAC but is formed on the surface of urethane or the like instead of TAC. When the transparent thin film layer 2A having a lower refractive index than the material is applied to the surface as an antireflection layer, the adhesiveness of the transparent thin film layer 2A is better than that of TAC, and the polarizing element 1
A transparent resin film that does not hinder the polarization function of A is manufactured as the surface base material 1B.

Therefore, for example, instead of the conventional TAC film, a transparent urethane film having a transparent thin film layer 2A having a lower refractive index than that of the urethane film formed as an antireflection layer on the surface is used in the usual manner. That is, the transparent urethane film (the antireflection substrate 2) on which the transparent thin film layer 2A is formed is replaced by the surface substrate 1B instead of the TAC film.
Then, a polarizing plate is manufactured by laminating it on the polarizing element 1A.

[0014]

Embodiments of the present invention will be described with reference to the drawings.

In this embodiment, the polarizing plate 1 having the most popular structure at the present time, that is, the optical properties such as translucency are good and P
There is no hindrance to the polarization function of the VA polarizing element 1A, and triacetyl cellulose (TAC) is formed on the front and back surfaces of the PVA polarizing element 1A because of its good protective function and shape retaining function.
The present invention is applied to a polarizing plate 1 which holds a film as a surface base material 1B.

Specifically, as shown in FIG. 1, in a polarizing plate disposed on the visible surface side of the liquid crystal display, it is laminated on the visible surface side of the polarizing plate 1 opposite to the liquid crystal display side. When a transparent thin film layer 2A having a lower refractive index than the base material is applied to the surface instead of the TAC film instead of the TAC film as the surface substrate 1B, the adhesion of the transparent thin film layer 2A is improved. Is better than TAC,
A transparent urethane film that does not hinder the polarization function of the polarizing element 1A was used as the surface base material 1B.

In the production, in the present embodiment, a conventional urethane film is used in place of the conventional TAC film by using a transparent urethane film in which a transparent thin film layer 2A having a refractive index lower than that of the urethane film is previously formed as an antireflection layer. Manufacture according to the street. That is, the transparent urethane film (the antireflection substrate 2) having the transparent thin film layer 2A formed thereon is laminated on the polarizing element 1A as the surface substrate 1B instead of the TAC film to manufacture a polarizing plate.

In commercialization, the T on the back side of the polarizing plate 1
A pressure-sensitive adhesive layer 4 for adhesion is formed on the AC film, and a separator film 5 is further releasably laminated on the back surface side of the pressure-sensitive adhesive layer 4.

Therefore, when the polarizing plate 1 is simply manufactured, the one surface substrate 1B on the front surface side is replaced with the TAC film, and the transparent thin film layer 2A (for example, fluorine resin) having a lower refractive index than the urethane film is reflected on the surface in advance. A good antireflection treatment can be applied to the surface of the polarizing plate 1 only by manufacturing using the transparent urethane film applied as the antireflection layer. That is, in the present embodiment, the transparent urethane film serving as the antireflection substrate is subjected to the existing antireflection treatment such as coating the surface thereof with, for example, a fluororesin (transparent thin film layer 2A) having a lower refractive index. The adhesion between the transparent urethane film and the fluororesin layer 2A is very good as compared with the case of coating on the TAC film, the optical properties are hardly affected, and the polarization function itself is not deteriorated. In addition, TAC is most suitable for the surface substrate on the liquid crystal display side of the polarizing plate based on many years of researches on the polarizing plate, but the surface substrate on the opposite side that is visible is compared to the surface substrate on the opposite side. Even if the optical properties are inferior, the polarizing function is not so affected. Therefore, even if the surface base material 1B on the surface side visually recognized instead of the TAC film is a transparent urethane film,
Does not interfere with the polarization function.

This point has been confirmed from the experimental results shown in FIGS.

There is also a method of vapor-depositing an inorganic low-refractive-index thin film layer as an antireflection treatment, but in this embodiment, the transparent thin film layer 2A of urethane film is formed by adopting the simple coating method as described above. It forms continuously on the surface.

When such continuous coating is performed, heat is applied, so that the surface substrate 1B of the polarizing plate 1 is TAC.
In the case of a film, it could not be performed because it deteriorates the optical characteristics of the TAC film and impairs the polarization function, but in this sense as well, in this sense, the surface substrate 1B of the polarizing plate 1 is used.
Is a transparent urethane film, and since this transparent urethane film is coated, continuous coating with heat is also possible.

[0023]

Since the present invention is constructed as described above, conventional antireflection processing can be easily performed, and the adhesion of the transparent thin film layer as the antireflection layer is good and the polarizing function is impaired. In addition, the surface reflectance of the polarizing plate can be reduced without roughening the surface, and it is sufficient to simply replace the conventional one surface base material with TAC, for example, and prepare urethane with a transparent thin film layer on the surface in advance. A polarizing plate with excellent mass productivity.

That is, if the transparent thin film layer is directly formed on the surface of the conventional polarizing plate, it is not practical because it does not adhere to the surface substrate (TAC) of the polarizing plate, and the surface of the polarizing plate is once hard coated. When the transparent thin film layer is formed after the layer is formed, it is not possible to carry out coating coating involving heat and it is necessary to use an evaporation method, so that it is not possible to improve mass productivity by continuous formation, Although it is not possible to adopt a manufacturing method that is inexpensive and is excellent in mass productivity, these problems are solved in the present invention, and it is possible to simply form a transparent thin film layer on the surface of the urethane film by simple coating such as continuous coating. This is an epoch-making polarizing plate that can be mass-produced at a low cost by the method and can be mass-produced at an extremely low cost.

Further, since the TAC film is not required on one side, the conventional hard processing is not required, and continuous processing is possible, resulting in excellent mass productivity and cost reduction.

The invention according to claim 2 is the TAC of the prior art.
The epoch in which the present invention can be easily realized by simply using a transparent urethane film as the surface substrate on the surface side that is visually recognized instead of the film, and the present invention can be reliably realized without affecting the polarization function. Becomes a polarizing plate.

Further, in the invention according to claim 3, the above-mentioned effect is surely exhibited only by laminating the transparent urethane film having the transparent thin film layer formed on the surface in advance in place of the TAC film on one side as the surface substrate. It becomes an extremely excellent polarizing plate.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a laminated state of the present example (also shows a conventional laminated state of a simple polarizing plate).

FIG. 2 is a table showing experimental results showing that the polarization characteristics of this example are not deteriorated as compared with the conventional mere TAC film cladding type polarizing plate.

FIG. 3 shows an experimental result showing that the adhesiveness of the transparent urethane film of the present example formed with a transparent thin film layer is better than that of a transparent thin film layer of a TAC film. table.

[Explanation of symbols]

 1 Polarizing Plate 1A Polarizing Element 1B Surface Substrate 2A Transparent Thin Film Layer

Front Page Continuation (72) Inventor Kazuo Maeda 1-5-5 Minamihonmachi, Joetsu City, Niigata Prefecture Arisawa Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A polarizing plate, which is formed by sandwiching and laminating a surface base material such as TAC on the front and back surfaces of a polarizing element, and is disposed on the visible surface side of a liquid crystal display body, and has a polarization opposite to that of the liquid crystal display body side. TA the surface substrate to be laminated on the visible surface side of the plate
Instead of C, when a transparent thin film layer having a lower refractive index than that of the base material, such as urethane, is applied to the surface instead of TAC as an antireflection layer, the adhesion of this transparent thin film layer is better than that of TAC. A polarizing plate characterized by using a transparent resin film as a surface base material that does not impair the polarizing function of the polarizing element. 2. A polarizing plate arranged on the front surface side of a liquid crystal display body, which is formed by sandwiching and laminating a surface base material using a TAC film on the front and back surfaces of a polarizing element, and is opposite to the liquid crystal display body side. The surface substrate laminated on the visible surface side of the polarizing plate was not a TAC film, but a transparent thin film layer having a lower refractive index than the base material was applied as an antireflection layer on the surface instead of the TAC film. At this time, a polarizing plate characterized by using a transparent urethane film as a surface base material, in which the adhesiveness of the transparent thin film layer is better than that of TAC and which does not hinder the polarizing function of the polarizing element. 3. A polarizing plate arranged on the front surface side of a liquid crystal display body, which is formed by sandwiching and laminating a surface base material using a TAC film on the front and back surfaces of a polarizing element, and is opposite to the liquid crystal display body side. The TAC film is not used as the surface base material laminated on the visible surface side of the polarizing plate of, and a transparent thin film layer having a lower refractive index than the base material is formed as an antireflection layer on the surface instead of the TAC film. A polarizing plate using the transparent urethane film as a surface substrate.