DE10030175A1 - Cell substrate, liquid crystal cell, liquid crystal display and method for producing an electrode - Google Patents

Abstract

The invention relates to a cell substrate comprising a resin substrate having a volatile component content reduced to 0.1% by weight or less, and a deposition film comprising a transparent electrode material, for example an ITO deposition film, applied to at least one Side of the resin substrate is applied. The adverse effects of the volatile components of the resin substrate evaporated during the deposition are excluded, so that the resulting cell substrate has good adhesion between the resin substrate and the deposition film and a low surface resistivity with little scatter.

Description

Field of application of the invention

The present invention relates to a resin cell substrate having a transparent film electrode with a low specific surface wi such as an ITO deposition film attached to the substrate firmly adheres. The resin cell substrate is suitable for the production of a liquid crystal cell or a liquid crystal display (a liquid crystal Visual display).

Background of the Invention

To account for the increasing display area of liquid crystal displays wear has been suggested instead of heavy and voluminous Glass substrates, a resin-based cell substrate comprising an epoxy resin, and The like. To use ver thereby the cell thickness and the cell weight wrestle. If a transparent film electrode, for example an ITO Deposition film is formed on such a resin-based cell substrate, however, there is a risk that the surface resistivity will drop below  Scattering increases and there arises a problem that the electrode film peels off as a result of poor adhesion to the substrate.

Summary of the invention

An object of the present invention is therefore to provide a resin cell substrate To provide a transparent film electrode with a low specific surface resistance, for example an ITO deposition film, which adheres well to the substrate, the substrate being a thin Can form liquid crystal cell with a light weight.

Another object of the present invention is to provide a liquid crystal To provide the cell using the resin cell substrate.

Yet another object of the present invention is to use Ver application of the liquid crystal cell, a liquid crystal display (a liquid crystal Visual display). It is also the aim of the present invention to specify a method for producing an electrode.

The cell substrate according to the invention comprises a resin substrate with a 0.1% by weight or less reduced volatile component content and a deposition film surrounding a transparent electrode material summarizes which is applied to at least one side of the resin substrate.

The inventive method for producing an electrode comprises Arrangement of a resin substrate which ver to 0.1 wt .-% or less has reduced volatile component content in a deposition chamber under reduced pressure and the formation of a deposition film (Coating film) comprising a transparent electrode material to minde least one side of the resin substrate using a deposition method driving.  

According to the invention, a resin cell substrate which has a transparent elec electrode film, for example an ITO film, which is deposited on the resin substrate traces and has a low specific surface resistance has little scatter, can be obtained, and using the Resin cell substrates can be a thin and light liquid crystal cell and Liquid crystal display (liquid crystal display) are manufactured. This Effects are due to the specific content of volatile compo component in the resin substrate of 0.1% by weight or less in the deposition of the transparent electrode film on the substrate.

As a result of extensive research aimed at the above To solve the problem described, it was found that in the event that a Resin substrate in a deposition chamber under reduced pressure is arranged to form an ITO deposition film and the like, the volatile Component evaporates in the substrate and diffuses into the chamber, whereby adverse effects arise and there is a dispersion of the specific Surface resistance and a decrease in adhesion between the Substrate and the deposition film. It has now succeeded in following Avoid partial influences of the gas by pretreating the resin substrate, to its volatile component content to 0.1% by weight or decrease less.

Brief description of the drawing

Fig. 1 shows a schematic cross-sectional view of the inventive SEN cell substrate.

Detailed description of the invention

The cell substrate of the present invention comprises a resin substrate having a volatile component content reduced to 0.1% by weight or less and a coating film comprising a transparent electrode material applied to at least one side of the resin substrate. An example of the cell substrate according to the invention is shown in FIG. 1, in which the number 1 represents a resin substrate, the number 3 a deposition film which comprises a transparent electrode material, and the number 2 represents an adhesive layer (intermediate layer) which is between the resin substrate 1 and the deposition film 3 is provided if necessary and if necessary.

The cell substrate is produced, for example, by a process in which the resin substrate, whose volatile component content is 0.1% by weight % or less has been reduced in a deposition chamber below is arranged under reduced pressure and a deposition film containing a trans parent electrode material comprises on at least one side of the resin substrate is formed using a deposition process. The volatile component in the resin substrate can be evaporated to ge be removed in a suitable manner, for example by heat degassing treatment, if desired under reduced pressure. To the formation separation film with good quality and good adhesion ensure the content of volatile component in the resin substrate preferably 0.09% by weight or less, particularly preferably 0.08% by weight or less, and most preferably 0.07% by weight or less.

The resin substrate used can be any of the suitable resins, for example from thermoplastic resins and thermosetting resins, be made. From the standpoint of heat resistance in manufacturing of the transparent, electrically conductive film are preferred wise resin substrates used, a resin with a glass conversion temperature of 130 ° C or higher, preferably 150 ° C or higher, esp ders preferably of 160 ° C or higher. Preferably that Resin substrate excellent transparency and high impact resistance on. It is particularly preferred to use a resin substrate which has a Light transmission of 80% or more, preferably 85% or more, having.  

In addition, from the standpoint of preventing denaturation of the liquid crystal and durability of the resulting liquid crystal cell, it is preferable that the resin substrate have chemical resistance, optical isotropy, low water absorption, low moisture permeability and gas barrier properties against oxygen and Like. Has. In addition, a resin substrate having a modulus of elasticity of 300 kgf / mm ² or more when a tensile stress of 0.2% is applied at 30 ° C, for example, from the viewpoint of suppressing the occurrence of deformation of the optical elements due to the resistance to dimensional changes under the Influence of temperature or humidity considered, preferably used in the manufacture of a liquid crystal display.

Examples of the resin for producing the resin substrate include thermoplastic resins such as polycarbonate, polyarylate, polyether sulfone, poly ester, polysulfone, polymethyl methacrylate, polyetherimide and polyamide; and thermosetting resins such as epoxy resins, unsaturated polyesters, polydiallyl phtha lat and polyisobornyl methacrylate. These resins can be either individually or in the form of a mixture of two or more of them. The Resins can also form in combination with other components copolymer or a mixture.

Resin substrates, taking into account the egg described above Properties that are used with particular preference are hardened products of epoxy resin compositions containing an epoxy resin, in particular a alicyclic epoxy resin, an acid anhydride hardener and a phosphorus Hardening catalyst included. Different types of alicy Clical epoxy resin are used and it is not subject to any special Restrictions.

Examples of the acid anhydride hardener include phthalic anhydride, 3.6- Endomethylene tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride,  Hexahydrophthalic anhydride, tetrahydrophthalic anhydride drid, methylhexahydrophthalic anhydride and methyltetrahydrophthalic acid reanhydride. Among these, colorless to pale yellow are preferred Acid anhydrides such as hexahydrophthalic anhydride, tetrahydrophthalic acid reanhydride, methylhexahydrophthalic anhydride and methyltetrahydrophthal acid anhydride used. The acid anhydride hardener is preferably used in one Amount of 0.5 to 1.3 equivalents per epoxy equivalent of the epoxy resin used.

Examples of the phosphorus curing catalyst include alkylphosphines, Phosphine oxides and phosphonium salts. The amount of phosphorus used Curing catalyst is 0.2 to 10 parts by weight, preferably 0.5 to 4 parts by weight, per 100 parts by weight of the acid anhydride hardener.

The resin substrate can be produced by a suitable method, which is selected, for example, from a casting mold process, a Flow casting process, an injection molding process, a roll coating tion molding process, an extrusion molding process, a transfer press process, a reaction injection molding process (RIM process) and the like. Ge if desired and if necessary, the molding material can be suitable additives kits such as dyes, modifiers, discoloration inhibitors, antioxidants onsmittel, Ultraviolettabsorber, release agents, reactive diluents and contain non-reactive diluents in such an amount that the Transparency is not affected.

The thickness of the resin substrate is, from the standpoint of a small thickness, low weight, high strength and resistance to Deformation considered, preferably 1 mm or less, especially be preferably 0.8 mm or less, most preferably 0.1 to 0.5 mm. The Resin substrate can be a single layer or a laminate with two or more Layers of the same or different types. In the case of a lami The thickness of the resin substrate is the total thickness of the laminate.  

The formation of a deposition film, which is a transparent electrode material on the resin substrate is not particularly limited, except that a resin substrate having the above limited volatile component content is used. The resin Substrate is reduced, for example, in a deposition chamber Pressure is arranged and an electrode material is applied using a conventional suitable method, for example by sputtering or Vacuum separation, separated. The deposition conditions like that reduced pressure and temperature can be conventional conditions gen correspond. In this case it is possible to directly use a transparent one electrically conductive film (deposition film) in a prescribed elec tread pattern condition.

The transparent electrode material that can be used in the present invention is not particularly limited, and conventional materials, e.g. As indium oxide, tin oxide, ITO (indium tin oxide), gold, platinum, palladium and mixtures thereof can be used. When forming the deposition film, an adhesive layer (intermediate layer) 2 having one or more layers of SiO ₂ , a hydrolysis and polycondensation product of a metal alkylate and the like may be provided on the resin substrate, if desired and necessary, to improve the adhesion and the like improve, as shown in Fig. 1.

A preferred cell substrate from the viewpoint of preventing deformation (warpage) is one in which the transparent electroconductive film comprising an ITO deposition film is on the resin substrate on an adhesive layer (intermediate layer) which is an SiO ₂ layer includes, is applied. The SiO ₂ layer can be manufactured in the same manner as described for the method of forming the deposition film.

To further improve the adhesion of the transparent electrically conductive Films, for example, as a result of an anchoring effect based on an un flat surface structure, the intermediate layer (adhesive layer), which comprises a hydrolysis and polycondensation product of a metal alkylate, contain inorganic oxide particles dispersed therein. The inorganic Oxide particles that can be used are suitable particles that are found in the inorganic oxide layer are transparent, and are examples of this Ren silicon dioxide, aluminum oxide, titanium oxide, antimony oxide and zirconium oxide. Among them, alumina particles are preferably used. That invented Cell substrate according to the invention can preferably be used for the manufacture position of liquid crystal displays, in particular liquid crystal cells. Rivers sig crystal cells are produced by a conventional process, at for example, so that a pair of cell substrates that have a transparent elec have electrode film in the form of an electrode pattern applied thereon, be arranged so that the surfaces of the transparent electrically lei tend to face each other, and in the space there is a Liquid crystal layer used. If desired, an Orientie Rungsfilm for the liquid crystal arrangement, which on the transparent elek trically conductive film has been formed, if necessary, after a con tional process. The type of liquid crystal cells that is to be produced is arbitrary and it includes a TN type, an STN Type, a TFT type and a ferroelectric liquid crystal type.

When manufacturing a liquid crystal cell, it is preferred for one cell to use a resin substrate whose light transmission is 60% or more, in particular 80% or more, at a wavelength of 600 nm, determined with a spectrophotometer when the resin substrate has a thickness of Has 0.4 mm. A liquid crystal display can be manufactured by Merging the liquid crystal cell described above and the optical elements described above, on one or both Sides of the cell are arranged to form a conventional structure.  

When manufacturing a liquid crystal cell or a liquid crystal display can, if desired, be a gas on the cell substrate or the resin substrate barrier layer may be provided to prevent moisture or sow material deforms (warps) the substrate or denatures of the liquid crystal. The gas barrier layer is usually produced represents from a polymer film, which serves the durability and the durability improve resistance to deformation.

Examples of suitable polymers for the production of the gas barrier layer belong to those who have a small oxygen permeability coefficient have, such as polyvinyl alcohol or a partial saponification product thereof, an ethylene / vinyl alcohol copolymer, polyacrylonitrile and polyvinylidene chloride. Vinyl alcohol-based polymers are because of their gas barrier properties and their moisture diffusion or absorption balancing properties prefers.

The gas barrier layer can be made by spreading a solution the polymer using a suitable coating process, for example a casting process or a spin coating process driving. The gas barrier layer has from the standpoint of transparency, ver prevents discoloration and gas shut-off properties Oxygen, water vapor and the like are preferably considered to have a thickness of 15 µm or less, particularly preferably from 1 to 10 µm.

If necessary, a protective coating can be provided on the resin substrate and the like be seen to improve surface scratch resistance. If that Resin substrate and the like. Has the gas barrier layer described above, a protective coating can be provided on the gas barrier layer. The Protective cover can be made from a suitable cross-linkable Resin that can form a transparent hard film, preferably of egg nem under the action of ultraviolet light curing resin, the comprises polyfunctional monomer which is crosslinked under the action of  ultraviolet radiation in the presence of a photocatalyst and the like under Formation of a three-dimensional network, for example a uretha acrylic resin or an epoxy resin.

The protective coating is made by spreading a resin solution on the Resin substrate, the gas barrier layer and the like using an appropriate one Coating process, for example a casting process, a sluice the coating process or a dip coating process, what crosslinking of the resin follows. The thickness of the protective cover can be determined in a suitable manner and is usually 200 microns or less, preferably 100 μm or less, particularly preferably 1 up to 50 µm.

The optical elements used in the manufacture of liquid crystal Displays used include a polarizing plate, a retardati onsfilm, a reflective plate, an elliptically polarizing plate, best consisting of a laminate of a polarizing plate and a retarda tion film, a reflective polarizing plate, an elliptically polarizing Plate using the reflective polarizing plate and the like The optical elements used are not subject to any particular restrictions and such can be used as in conventional Liquid crystal displays are used.

An optical element or more than one optical element can be used. Two or more optical elements can be previously connected to each other by means of an adhesive layer and the like and used as a laminate. The adhesive layer can consist of a suitable self-adhesive (pressure-sensitive) adhesive. In order to prevent the detachment (separation) of the optical element or a deformation of the cell substrate, it is preferred that the self-adhesive (pressure-sensitive) adhesive layer has a 1000% modulus of elasticity at 90 ° C. of 3 to 10 g / mm ² , preferably of 4 up to 8 g / mm ² .

The self-adhesive layer of adhesive has, but is not limited to, preferably an adhesive strength of 400 to 1000 g / 25 mm, expressed as 90 ° peel strength (room temperature up to 70 ° C; peeling speed 300 mm / min) on the cell substrate, with the reusability of the rivers sig crystal cell is taken into account in the event of incorrect bonding.

The adhesive layer is not subject to any special conditions with regard to the material restrictions and can be made from sticky substances or self-adhesive (pressure-sensitive) adhesives that act as a base polymer suitable polymer such as acrylic resins, silicone resins, polyester, polyurethane, Po lyether or synthetic rubber. Preferably used those that have excellent optical transparency, medium adhesion or Tackiness properties (i.e. wettability, cohesive strength and adhesive strength) and excellent resistance to weathering and heat such as self-adhesive acrylic adhesives. For the self-adhesive glue layer, it is preferred that they have low moisture absorption and has high heat resistance, which is desirable to foam phenomenon or a separation phenomenon as a result of the absorption of Prevent moisture to deteriorate the optical properties as a result of a difference in the coefficient of thermal expansion prevent efficient and the like. And to high quality and durable Get liquid crystal displays.

This self-adhesive layer of adhesive can contain suitable additives, such as usually in self-adhesive (pressure-sensitive) adhesive layers are used, e.g. B. natural or synthetic resins, in particular tackifying resins, fillers such as glass fibers, glass beads, metal powder and other inorganic powders, pigments, colorants and antioxidants tel. Fine particles can also be incorporated to make them self-adhesive to give the adhesive layer light scattering properties.  

The self-adhesive layer of adhesive can be made using a suitable method for distributing a self-adhesive adhesive solution or dispersion using a casting process or a Be stratification process or using an educational process a self-adhesive adhesive film on a separator to the above way described and for the transmission of the film. The self-adhesive Adhesive layer can be in the form of a laminate of two or more layers with different compositions or different types be brought. The thickness of the self-adhesive layer can be appropriate Neter be determined depending on, for example, the type of Substrate, however, it is usually 1 to 500 microns.

The liquid crystal display can be made using a suitable method be produced, for example a method for producing a Liquid crystal cell using the cell substrate that was previously attached to it attached required optical elements, or a method in which the required optical elements on the cell substrate provided liquid crystal cell can be attached. When making the liquid crystal displays become a polarizing plate, a retardation film and Arranged in predetermined positions and the treated positions can be of a conventional type.

The resin-based cell substrate according to the invention has flexibility, so that of easily on a curved surface or an extensive area can be applied. For example, the cell substrate can be of various types NEN types of liquid crystal cells, for example active matrix types for example with a TFT mode, and simple matrix types, for example se with a TN mode and an STN mode, for producing different Liquid crystal displays are used.

The present invention will hereinafter be described with reference to the fol ing examples explained, but it is clear that the invention is by no means  is limited to this. All parts and percentages specified therein are by weight unless otherwise stated.

example

A mixture of 100 parts of an alicyclic epoxy resin of the following formula:

125 parts of methylhexahydrophthalic anhydride and 1 part of tri-n- Butyloctylphosphonium bromide was poured into a mold and stirred for 2 hours Cured 120 ° C to obtain a 0.4 mm thick resin substrate.

The resin substrate was subjected to a heat degassing treatment at 150 ° C for 1 hour to reduce the volatile component to 0.06%. The resulting resin substrate was placed in a deposition chamber. First, using a sputtering process under the conditions RF: 500 W; Ar gas: 30 cm ³ ; and pressure: 3 mTorr an SiO ₂ layer with a thickness of 200 Å was formed. To produce a cell substrate, ITO with a thickness of 2000 Å was used using a sputtering process under the conditions DC: 0.3 A; Ar gas: 40 cm ³ ; O ₂ gas: 0.5 cm ³ ; and pressure: 4 mTorr formed. The main component that evaporated from the resin substrate during the sputtering process was water.

Comparative example

A cell substrate was obtained in the same manner as in Example 1, wherein however, this time the resin substrate is not subjected to a heat degassing treatment  has been. The volatile component content in the resin substrate was 1.49%.

Assessment test

The surface resistivity of the ITO transparent electroconductive film in the cell substrates obtained in the above example and the comparative example was determined. In addition, each cell substrate was 150 s long immersed in a 2.5% strength aqueous sodium hydroxide solution of 40 ° C turned and the surface was observed under a Miokroskop to the adhesion of the transparent electroconductive ITO film to be tested. The results obtained are shown in the table below.

table

While the invention has been described above by specific examples thereof described in detail, however, it will be apparent to those skilled in the art that various Changes and modifications can be made without there is left by the scope of the present invention.

Claims (5)

1. Cell substrate, which comprises a resin substrate, which has a 0.1% by weight or less reduced volatile component content, and ei A deposition film comprising a transparent electrode material which is applied to at least one side of the resin substrate. 2. A cell substrate according to claim 1, wherein said resin substrate is one Epoxy resin. 3. A liquid crystal cell comprising the cell substrate according to claim 1. 4. A liquid crystal display comprising the liquid crystal cell according to claim 3 sums up. 5. A method of manufacturing a film electrode comprising the assembly a resin substrate which reduced one to 0.1% by weight or less Contains volatile component in a deposition chamber un ter reduced pressure and the formation of a deposition film which a comprises transparent electrode material, on at least one side of the Resin substrates using a deposition process.