JPH06265720A - Color filter substrate and production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To improve the adhesive power of a conductive film and to obtain excellent curing to improve the fine working characteristic of the conductive film by irradiating a substrate formed with a resin protective layer with UV light, then forming an intermediate film and further, forming the conductive film. CONSTITUTION:The substrate formed with the resin protective layer 3 is irradiated with the UV light and thereafter, the intermediate film 5 is formed and further, the conductive film is formed in the process for production of the color filter substrate consisting of a laminated structure composed of a transparent base body 1, a color filter layer 2, the resin protective layer 3 and the conductive film 4. Namely, either of a pair of the substrates is formed as the color filter substrate and the other as the substrate with the properly patterned electrodes. Liquid crystal oriented films are formed on the substrates at need and thereafter, a pair of the substrates are so disposed that both sides of the electrodes face each other. The peripheral part is then sealed and a liquid crystal is sealed therein. As a result, the liquid crystal display body having high brightness is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color filter substrate for use in a color display device, and a method of manufacturing a liquid crystal display device using the same.

[0002]

2. Description of the Related Art The basic structure of a color filter substrate with a transparent conductive film used in a conventional color liquid crystal display device comprises a transparent substrate / color filter layer / resin protective layer / conductive film.

The conductive film is mainly used as a transparent electrode of a liquid crystal display element. For the conductive film, a transparent conductive metal compound thin film typified by a tin-doped indium oxide (ITO) thin film is formed on the color filter by a PVD method such as a sputtering method or a vacuum deposition method. Fine processing (patterning) is generally performed through a wet etching process. In this case, a resin protective layer is often provided between the color filter and the conductive film to protect the color filter from heat and chemicals such as acid used in the transparent electrode processing step.

However, depending on the composition of the resin protective layer and the film forming conditions of the conductive film, sufficient adhesion of the resin protective layer / conductive film cannot be obtained, and peeling occurs or undercutting occurs during patterning of the conductive film. However, there was a problem that the stability of patterning was affected by the side etching.

[0005]

The present invention has been made to solve the above problems, and is a method for manufacturing a color filter substrate having a laminated structure of a transparent substrate, a color filter layer, a resin protective layer, and a conductive film. In, a method for manufacturing a color filter substrate and a method for manufacturing a liquid crystal display element, which comprises irradiating a substrate having a resin protective layer with UV, then forming an intermediate film, and further forming a conductive film To do.

FIG. 1 is a cross section of a color filter substrate of the present invention. 1 is a transparent substrate, 2 is a color filter layer,
3 is a resin protective layer, 4 is a conductive film to be patterned,
Reference numeral 5 is an intermediate film containing a metal oxide as a main component.

In the present invention, the conductive film 4 and the resin protective layer 3
The intermediate film 5 provided to improve the adhesion of
A film containing at least one of O ₂ , ZrO ₂ , Al ₂ O ₃ , and SiO ₂ as a main component is given as a typical preferable example, but other metal oxides may be used.

The thickness of the intermediate film is 2 nm to 80 nm, preferably 10 nm to 50 nm. If the thickness is less than 2 nm, a sufficient effect of improving the adhesive force cannot be obtained.
If it is thicker than this, the internal stress of the interlayer film becomes large, and the effect of improving the adhesive strength is also lowered, and cracks may occur.

If the surface of the resin protective layer 3 is subjected to UV cleaning before the application of the intermediate film 5, the adhesive force can be further improved. A low-pressure mercury lamp is used as the ultraviolet ray generation source, and the irradiation amount is preferably 300 to 1500 mJ / cm ² .

The intermediate film is composed of a metal oxide film obtained by dehydration condensation of a raw material composed of an organometallic compound. Two
This is because an intermediate film having excellent characteristics can be obtained at a relatively low temperature of about 50 ° C. or less, which is advantageous in terms of cost. In this case, spin coat method, roll coat method, printing method, dip method, spray method and the like are applied to the color filter with a liquid containing an organometallic compound, and then dried by heating at about 150 ° C. to 250 ° C. for dehydration. It may be condensed to form a metal oxide film. Further, the reaction may be accelerated by ultraviolet rays.

The organometallic compound in the coating solution is T
Examples thereof include metal alkoxides of at least one of i, Si, Zr, and Al, metal isocyanates and hydrolysates thereof, and mixtures thereof. Also, Ti, Z
For r and Al, the acetyl acetate can be used as well.

For example, as the titanium alkoxide, titanium octylene glycol (TOG), tetrabutyl titanate (TBT), tetraethyl titanate, tetraisopropyl titanate, tetraalkyl titanate such as dimethyldipentyl titanate, and oligomers thereof are typical. Can be mentioned. Further, it is also possible to use a compound in which the alkoxy group of the above compound is substituted with an alkyl group, such as alkyltrialkoxytitanium.

Typical examples of zirconium alkoxides include tetraalkyl zirconates, especially tetrabutyl zirconate, and oligomers thereof. Besides, alkyltrialkoxyzirconium and the like can be used.

Typical examples of silicon alkoxides include tetraalkoxysilanes such as tetraethyl silicate and tetrabutyl silicate, and oligomers thereof. Also, an alkyltrialkoxysilane in which the alkoxy group of the above compound is substituted with an alkyl group can be used.

The above-mentioned metal alkoxide and the like are hydrolyzed by water in a solvent, dehydrated and condensed by drying and baking, and gelled.

In the present invention, a catalyst necessary for further promoting such a reaction can be added to the coating liquid. Specifically, hydrochloric acid, nitric acid, acetic acid, sulfonic acid or the like can be used.

The type and mixing ratio of at least one alkoxide of Ti, Si, Zr, and Al may be determined in consideration of optical characteristics (refractive index, etc.), mechanical / chemical durability, etc. .

The color filter layer 2 of the present invention is not particularly limited, and may be one made of gelatin by a dyeing method, one made by an electrodeposition method, and one having a pigment dispersed in a resin such as a polyimide resin or an acrylic resin.

The pattern of the color filter is not particularly limited and may be, for example, a stripe pattern, a mosaic pattern, a delta pattern or the like. Further, in order to improve the contrast, a light-shielding pattern such as a black matrix may be formed between the patterns, and the black matrix may be formed by depositing a metal film of chromium or the like by a vapor deposition method, a sputtering method, or the like, or a black The photosensitive resist may be patterned by photolithography.

Examples of the material of the resin protective layer 3 of the present invention include various resins such as acrylic resins, epoxy resins, polyimide resins, and silicone resins, but are not particularly limited.

The resin protective layer 3 is applied onto the color filter layer 2 by a spin coating method, a roll coating method, a dipping method, or a spraying method, and its film thickness is generally 1 to 10 μm, but it is not particularly limited. Not a thing.

The method for producing the color filter substrate according to the present invention will be described below by taking as an example the case where a color filter layer using a colored resist in which a pigment is dispersed in a resin and an acrylic resin protective layer are adopted.

First, a light shielding layer called a black matrix is formed on a transparent substrate such as glass or plastic.
This light-shielding layer is provided in the liquid crystal element of the TFT system to maintain the characteristics of the transistor or prevent the deterioration of contrast, and is usually formed of a chromium thin film having excellent light-shielding properties.

In the simple matrix drive represented by the STN (Super Twisted Nematic) system, the contrast of the device is originally lower than that of the TFT system, and the black matrix is required because of the demand for cost reduction. It is often omitted, formed by superimposing three primary colors, or formed of a single color resist.

Next, a colored resist containing a dye such as a pigment and a photosensitive resin is applied on the substrate, and a PVA (polyvinyl alcohol) layer or the like as an oxygen barrier film is applied on the colored resist, and then the predetermined resist is applied. Exposure is performed through the photomask having the pattern shape, and then the unexposed portion is removed by development to form a color pattern. This operation is repeated twice with another color to form a color filter of three primary colors.

On top of this, an acrylic resin is added to the resin protective layer 3
To form. As a forming method, it is general to apply by a spin coating method, a roll coating method, a dipping method, and then cure in a clean oven or a hot plate, but another method may be used.

Next, a liquid containing the organometallic compound is applied onto the resin protective layer 3. The coating liquid layer may be cured by heating with an oven, a hot plate, a far infrared heater, or the like. Also, UV irradiation may be used together. Further, the film may be formed by patterning at the time of application.

Next, a conductive film (electrode layer) is formed on the protective layer.
4 is formed. The transmissive display needs to be light transmissive, and in particular, tin-doped indium oxide (IT
A typical example is a thin film of O) or tin oxide, zinc oxide doped with F, Al, and Sb, but other metal compound thin films may be used.

When not used as a transmission type display,
It does not necessarily have to be transparent, and aluminum or chrome may be used in some cases. Further, as a means for improving the adhesive force between the intermediate film 5 and the conductive film 4, UV cleaning of the surface of the intermediate film 5 before forming the conductive film 4 can be mentioned.

Although it is desirable that the conductive film 4 be patterned according to the display, it may be a solid electrode when it is used as a common electrode. As a method of forming the conductive film 4, a vacuum deposition method, a magnetron sputtering method, or the like is preferably used from the viewpoint of making the film thickness uniform, but is not particularly limited thereto.

In the present invention, TFTs, MIMs, active elements such as thin film diodes, retardation films, polarizing films, reflection films, photoconductive films, etc. are formed above or below the electrodes as required. Good.

Further, in the case of a liquid crystal display, an alignment film is formed on the electrode-attached substrate as needed. This may be obtained by rubbing an organic resin film of polyimide, polyamide, polyvinyl alcohol or the like, obliquely vapor-deposited SiO _x or the like, or applied with a vertical alignment agent.

Further, as a method for producing a liquid crystal display, a method usually used can be adopted. That is, one of the pair of substrates is the color filter substrate, the other is an appropriately patterned substrate with electrodes,
A liquid crystal alignment film is formed on the substrates as needed, and then the pair of substrates are opposed to each other on the electrode surface sides and the peripheral portions are sealed to enclose the liquid crystal therein. This makes it possible to obtain a liquid crystal display having high definition.

Applications of the color filter substrate of the present invention include a liquid crystal display surface, a cathode ray tube display surface, a light receiving surface of an image pickup tube, and the like. In particular, since a color filter having a relatively small thickness unevenness can be obtained, it is preferable as a liquid crystal element in which the accuracy of the space between substrates is strictly required.

[0035]

In the present invention, the mechanism of action for improving the adhesive force of the intermediate film containing a metal oxide as a main component is not always clear, but the intermediate film 5 containing a metal compound as a main component is electrically conductive to the resin protective layer 3 and the conductive film. It is considered that the above-mentioned effects are produced by acting as a binding hand with the membrane 4.

[0036]

Example A color filter made of a resin in which a pigment is dispersed is applied to a transparent substrate made of a transparent glass substrate to a thickness of 5 μm by a printing method, and further, an acrylic resin is coated to a thickness of 3 μm as a resin protective layer 4 by a roll coater method. The contact angle of water on the substrate at this time was 31 degrees.

On top of that, a low-pressure mercury vapor lamp (Oak Seisakusho, trade name "HMW-667": wavelength 254 nm) is used.
When irradiated with an intensity of 600 mJ / cm ² , the contact angle of water was 4.5 degrees, and it was confirmed that the surface was cleaned.

Again, a transparent substrate made of a transparent glass substrate is coated with a color filter made of a resin in which a pigment is dispersed to a thickness of 5 μm by a printing method, and further, an acrylic resin is coated as a resin protective layer 4 to a thickness of 3 μm by a roll coater method. . On top of that, 1
Irradiation with an intensity of 200 mJ / cm ² and then coating with a solvent-diluted organometallic compound shown in Table 1 with a spin coater, heating at 200 ° C. to promote the hydrolysis reaction,
An intermediate film made of a metal oxide having a thickness shown in Table 1 was formed. Furthermore, a transparent conductive film made of ITO having a thickness of 250 nm was formed thereon by magnetron sputtering.

After a line-shaped resist (masking agent) is formed on the ITO film, it is immersed in a hydrochloric acid / ferric chloride-based etching solution (etchant) to perform fine processing (patterning) of the ITO film. It was As a result, the side etching amount of the ITO film on the intermediate film (SE amount: the amount by which the etching progressed and became thinner than the width of the resist) was as shown in Table 1. Examples 1, 2, and 7 are comparative examples.

In the examples, the amount of side etching of the ITO film when the ITO film was patterned was very small and good. Further, the sheet resistance value of the ITO film of the example was 9 to 10 Ω / □, which was almost the same as the value of the ITO film formed on the glass substrate, and almost no increase in the specific resistance value of the ITO film due to the intermediate film was observed. It was

The electrode substrate with a color filter obtained in Examples 4 and 5 was used as one substrate, and an alignment film obtained by rubbing a polyimide film on the surface was formed together with the other substrate with an electrode. As the liquid crystal, a liquid crystal ZLI2293 (trade name, manufactured by Merck Ltd.) added with a chiral compound
It is sandwiched between these substrates using a 240 degree twist of 1
A / 240 duty liquid crystal display device was produced. When this liquid crystal display device was driven, it was confirmed that there was little in-plane color difference, good contrast and color reproducibility, and high-quality full-color display was possible.

[0042]

[Table 1]

[0043]

INDUSTRIAL APPLICABILITY The present invention has an excellent effect that the adhesive force of the conductive film is improved and the fine processing property (patterning property) of the conductive film is improved in the color filter substrate with the transparent electrode, and especially the side etching is performed. It has the effect of solving various problems such as undercut.

Further, by using the wet method and forming the intermediate film from an inexpensive liquid raw material, there is an economical advantage that the manufacturing cost is low and a high quality color filter substrate can be obtained.

Further, the adoption of the protective layer has an advantage that the specific resistance value of the conductive film typified by ITO can be made as low as that of the transparent conductive film when it is formed on the glass substrate.

[Brief description of drawings]

FIG. 1 is a sectional view of a color filter substrate according to the present invention.

[Explanation of symbols]

 1: transparent substrate 2: color filter layer 3: resin protective layer 4: conductive film 5: intermediate film

Claims (3)

[Claims] 1. A method of manufacturing a color filter substrate having a laminated structure of a transparent substrate, a color filter layer, a resin protective layer, and a conductive film, wherein the substrate having the resin protective layer is irradiated with UV and then an intermediate film is formed. A method of manufacturing a color filter substrate, further comprising forming a conductive film. 2. The intermediate film is made of TiO ₂ , ZrO ₂ , Al ₂ O.
_{3. The} method for manufacturing a color filter substrate according to claim 1, wherein the film is a film containing at least one selected from SiO ₃ and SiO ₂ as a main component. 3. The color filter substrate manufactured by the method for manufacturing a color filter substrate according to claim 1, as at least one of a pair of substrates,
A method of manufacturing a liquid crystal display element, comprising sandwiching a liquid crystal layer between the pair of substrates.