JPS61246719A - Polarizing film united type transparent conductive film - Google Patents

Abstract

PURPOSE:To improve an optical transmittivity of the titled film, and to give a glaze shield effect to the titled element by providing a transparent conductive coating film on a surface of the transparent conductive film which laminately adhered on both surfaces of the polarizing film, and a coating layer having a less refractive index than that of a PES film on an another surface of said film. CONSTITUTION:The PES film or the polysulfone film (PS) film are laminated and pressed under a pressure with an U.V. curing adhesives on both surfaces of the polarizing film which contains a two colored dyestuff and is stretched to a uniaxial direction to remove an air contained in the laminated part, and then is provided the transparent conductive film on one surface of the obtd. polarizing film. And further the transparent coating film of the cured resin which has the less refractive index than that of the PES or PS film, and contains a three dimensional cross-linking structure due to an irradiation of an U.V. ray is provided on the opposite surface of the obtd. polarizing film. By constituting the titled film as mentioned above, the optical transmittivity of he titled film is improved, and the glaze shield effect is given to the titled film.

Description

Detailed Description of the Invention The present invention relates to a polarizing film-integrated transparent conductive film used for liquid crystal display cells, in which a polarizing film containing a dichroic dye and a transparent conductive film are integrated. The film is laminated with a polarizing element film sandwiched between the two films using an ultraviolet curable adhesive, creating a three-layer structure. The present invention relates to a polarizing film-integrated transparent conductive film on which a small transparent cured resin layer that is cured by ultraviolet rays is formed.

Conventionally, substrates in which a conductive thin film is formed on glass have been widely used as conductive substrates to form liquid crystal display cells, but they are easily broken, have poor continuous productivity, and have limitations in thinning. In recent years, transparent conductive films in which a thin film is formed on a transparent film with a low birefringence index have begun to be used. A general method for manufacturing a liquid crystal cell using this film is as follows.

1. A circuit board having a letter Z turn and an electrode circuit is formed by etching a conductive thin film using a transparent conductive film.

2. Next, a polyimide resin is applied and cured on the circuit surface, and an alignment film is formed by rubbing.

3.Next, a sealant is printed on the four circumferences of the six-tipped circuit surface, except for the liquid crystal injection port, and the two circuit boards are pasted together via the sealant and hardened.

4. After liquid crystal is injected into the gap formed by the two substrates, the injection port is sealed with resin.

5. A liquid crystal display cell is assembled by attaching polarizing plates sandwiched between films and coated with adhesive on one side to the upper and lower surfaces of the obtained cell.

However, when using such a method, it is necessary to attach a polarizing plate to each formed liquid crystal cell via an adhesive, which requires a large amount of man-hours, and the presence of an adhesive layer makes it difficult to attach a polarizing plate to the liquid crystal cell. Problems arise such as the reliability of the liquid crystal is poor due to poor airtight sealing between the two, and it is difficult to obtain reliability of the liquid crystal because the excellent oxygen barrier properties of stretched ivar containing a dichroic dye, which is normally used in polarizing elements, cannot be utilized. .

As a method to solve these problems, a polarizing element film is sandwiched between support films with low birefringence via an adhesive layer to form a three-layer structure, and then a transparent conductive thin film is formed on one side of the support film. A conductive film integrated with a polarizing film has been proposed. This method is an excellent method for obtaining a liquid crystal cell with a polarizing plate in the sense that it overcomes the drawbacks of the current film liquid crystal cell.

However, in this method, a cellulose film such as a triacetyl cellulose film is usually used as a support film, but since this film has poor moisture resistance, it is expected that the dimensions will change during the wet process such as etching, and the sealing of the upper and lower electrodes will be difficult. It has not been put into practical use because it is very difficult to bond with adhesives and because of its poor heat resistance, it cannot withstand the high temperatures during alignment film formation and causes deformation. In this regard, +61J ether sulfone and polysulfone films, which have little dimensional change when wet, are heat resistant, and have low birefringence, have been reviewed and extensive research and development has been carried out to put them into practical use. (hereinafter PES fi#A, Akira-4→
= 耘-Sen PS film) However, PES,
As is well known, PS film is a film with a high refractive index, which results in a high surface reflectance and low total light transmittance, so when used as a liquid crystal cell, it may become dark or cause glare due to high reflection. This has not yet been put into practical use due to the problems that occur.

In addition, thermosetting resins such as epoxy resins and urethane resins are usually used as adhesives for the purpose of integrating the base film and the support, but they require a long time to heat, have poor weather resistance, and are not colored. Nothing definitive has been found yet, such as ease of use. The inventors of the present application have clearly grasped this situation, and have conducted intensive studies to commercialize an integrated film, which has not been put to practical use in the past, and have arrived at the present invention. That is, by selecting a PES or PS film obtained by melt extrusion as a support, problems related to moisture resistance and heat resistance can be overcome, and in addition, ultraviolet ray resistance can be ensured by selecting an ultraviolet curing transparent adhesive for lamination bonding. and further PES or PS
By forming one or more W cured resin layers with a smaller refractive index than the film on one side of the film to improve total light transmittance and also impart anti-glare properties, we have discovered an excellent integrated conductive film. Ta.

The details of the present invention will be described below.

The polarizing element film used in the present invention is an element film having polarizing ability, and generally, a t' ribinyl alcohol-iodine type film or an olefin/vinyl alcohol copolymer type-iodine type uniaxially stretched element film is used.

Moreover, a pyrivinyl alcohol-dichroic dye-based polarizing element film is preferably used. In particular, the use of a dichroic dye system that has light absorption characteristics in the ultraviolet wavelength range of 400 nm or less and is heat resistant will result in a decrease in polarization ability during bonding with W light irradiation, and a decrease in polarization ability during heat-resistant treatment. This is particularly desirable in terms of preventing.

The support film to be laminated with the polarizing element film is a PES or PS film obtained by melt extrusion, and is a transparent film with a total light transmittance of 80 inches or more, and its birefringence (retardage value) is It is preferable that the field of view is as small as possible, provided that this does not occur and the appropriate field of view does not become narrow. Further, the film thickness is preferably 50 to 200 μm, and if it is less than 50 μm, it will be difficult to handle in the processing process, and if it is more than 200 μm, the total light transmittance will decrease. Moreover, a purple ray curing transparent adhesive is used as an adhesive between the PES or PS film serving as the support film and the above-mentioned base film.

Adhesion between the previnyl alcohol base film and the PES or PS film is essential for the adhesive.

As such adhesives, adhesives are used in which an acrylate oligomer such as epixyacrylate, urethane acrylate, or ester acrylate is used, an acrylic or methacrylic monomer is used as a diluent, and a sensitizer is further added. In particular, a combination of a urethane acrylate oligomer and a monomer containing a hydroxyl group, a carboxyl group, a phosphoric acid group, etc. is a very preferable combination in that it has good adhesion to both PES and polyvinyl alcohol polarizer films.

Next, the three layers are laminated and pressed together using a laminator, and the air inside is removed. The thickness of the adhesive layer is preferably from 5 to 50 .mu.m.If the thickness is less than this, there will be problems in adhesion reliability, and if it is more than 50 .mu.m, the laminated film will be wavy.

The obtained three-layer laminate is cross-linked and cured by irradiating W light from both sides of the PES film. In addition, thermal annealing is also an appropriately used method to complete the reaction after irradiation.

A three-layer structure sandwiched between supports is thus obtained, which is then provided with a thin conductive layer on one side. In this case, a vacuum evaporation method and a star/ξ stumbling method are used.

The film thickness is 100 to 1000, and the resistance value is 0.1 to 5V.
Jj/mouth. In this case, the total light transmittance is 40-4
It showed 5chi.

Next, a transparent ultraviolet curable resin that provides a cured product having a refractive index lower than that of the PES and PS films is applied to the other side and cured.

Furthermore, since the refractive index of the PES film is as high as 1.65, a wide range of resins can be selected for the ultraviolet curable resin that is applied and cured.
A system in which an acrylic oligomer such as terether acrylate is diluted with various polyfunctional acrylate monomers can be used. Although the effect is remarkable even with a single layer of coating, particularly good results can also be obtained by forming several layers with lower refractive index in sequence from the film surface.

The light transmittance of the conductive film integrated with the polarizing film thus obtained is several orders of magnitude higher than that of a conductive film without a low refractive index layer, and is an industrially significant laminated film exhibiting an anti-glare effect. Met.

Examples are shown below.

Example 1 Urethane diacrylate consisting of polyether diol and aliphatic incyanate 60 parts by weight (2-hydroxyethyl methacrylate) 30 parts by weight trisacryloxyethyl phosphate 10 parts by weight Dimethylbenzyl ketal 2 parts by weight From the above composition A 100 μ thick ether sulfone film (total light transmittance s a O%) is applied to the adhesive consisting of 9.

It was coated on one side of the film with a refractive index of 1.65) by a roll coater method to a thickness of 20 μm. Next, the vinyl alcohol-dichroic dye-based polarizing element film is sandwiched between two films having the adhesive layer, with the adhesive layer facing inward.
It was crimped with air pressure. 80W/m on both sides of this three-layer film
The sample was irradiated twice with a high-pressure mercury lamp at a distance of 15 m/min at a speed of 5 m/min, and then heat-treated at 120° C. for 10 minutes.

On one side of the obtained polarizing plate, indium-tin oxide was splattered to form a transparent conductive layer having a thickness of 300 mm. The optical properties of this polarizing film-integrated transparent conductive film (3) are shown in Table 1.

Next, a coating agent consisting of the following composition 9 was applied to the surface opposite to the transparent conductive layer of the conductive film in a thickness of 5 μm using a roll coater method, and a high-pressure mercury lamp of 80 W/m was applied to this coated surface at a distance of 153 mm. Irradiation was performed once at a speed of 5 m/min.

Urethane diacrylate consisting of Bori ether Boriol and aliphatic isocyanate system 40 parts by weight Pentaerythritol tetraacrylate 40 parts by weight 1.6-hexanediol diacrylate 20 parts by weight Dimethylbenzyl ketal 2 parts by weight Note that the refraction of the cured film of the coating agent The ratio was 1.52.

The optical properties of the obtained polarizing film-integrated transparent conductive film are shown in Table 1.

(B) No dimensional change was observed in either film due to heat treatment.

As described above, the transparent conductive film obtained by laminating and adhering pyriether sulfone on both sides of a polarizing element film based on bolivinyl alcohol-dichroic dye has excellent heat resistance, and also! +) By providing a coating layer having a refractive index smaller than that of the ether sulfone film, it became possible to improve light transmittance and provide an anti-glare effect.

Claims (1)

[Claims] A polyether sulfone or polysulfone film is laminated and bonded with an ultraviolet curing adhesive on both sides of a polarizing element film containing a dichroic dye and stretched in a uniaxial direction, and a transparent conductive coating is applied to one side, and a transparent conductive coating is applied to the opposite side. 1. A transparent conductive film integrated with a polarizing film, comprising a coating layer of a cured resin that is transparent and has a refractive index lower than that of a polyether sulfone or polysulfone film, and is three-dimensionally crosslinked when irradiated with ultraviolet rays.