JPH07301793A - Production of color filter and liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a color filter and a liquid crystal display device in which leaking of light can be prevented and sharp colors and excellent optical characteristics are obtd. CONSTITUTION:A substrate having a transparent conductive layer 2 as a lower layer and a photoresist layer 3 as an upper layer formed into a circuit state is obtd. Then (e) the photoresist layer is formed into fine chips, and if necessary, the photoresist layer is heat treated. (f) A light-shielding resin layer 4 is formed on the substrate. (g) The substrate is exposed through the back surface to develop and to remove the unexposed part of the light-shielding resin layer. (h) During the unexposed part of the resin layer is removed or after removed in the process (g), the surface of the transparent conductive layer in the process (e) is exposed to air. (i) A color layer 5 is formed on the transparent conductive layer exposed to air in fine chip state by electrodeposition method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter and a method for manufacturing a liquid crystal display device. More specifically, the present invention relates to a novel method for producing a color filter having a striped colored layer and a light-shielding coating film in the gap, and a method for producing a liquid crystal display device using the color filter.

[0002]

2. Description of the Related Art Liquid crystal display devices (LCDs) have been used for so-called pocket televisions and the like, but in recent years, their size and screen have been rapidly increased. In terms of image quality, the development of active driving elements represented by STN liquid crystal and TFT from TN liquid crystal has commercialized products that approach CRT. For color filters used for making LCDs multi-colored, various studies have been conventionally conducted to improve image quality and productivity. In particular, in order to prevent light leakage and improve image quality, it is important to study a light-shielding coating film called a black matrix formed in the gaps between the colored layers of red, green and blue. In particular, in a TFT-type color LCD, which is expected to be promising in the future, it is required to improve the light-shielding rate of the light-shielding coating film, and the pattern of the light-shielding coating film is required to have a grid pattern.

As a method for forming a light-shielding coating film which fills the gaps between the colored layers of the color filter, a silk screen method,
A method based on a printing technique such as an offset method is known. Further, a colored layer is formed by an electrodeposition method on a stripe-shaped conductive circuit that is insulated from each other provided on a substrate, and then a photocurable resin composition that gives a light-shielding coating film is applied to the entire surface, There is also known a method of forming a light-shielding coating film in the gap between stripe-shaped colored layers by exposing and developing from the back surface of the substrate using the colored layer as a mask (JP-A-62-247331). . However, in the conventional printing method, the interstitial space is about 100.
Only a rough pattern of about μm can be formed, and it is difficult to accurately form a light-shielding coating film in a grid pattern. Also,
According to the method described in Japanese Patent Application Laid-Open No. 62-247331, it is difficult to form the colored layer into strips and form the light-shielding coating film in the lattice-like gaps.

[0004]

The present inventors have applied a method of electrodeposition coating capable of selectively forming a colored layer only on a conductive circuit with extremely high precision, and skillfully made a positive photoresist. The inventors have found that the above-mentioned conventional problems can be solved by using them, and have completed the present invention.

That is, according to the present invention, (a) a transparent conductive layer is formed on a transparent substrate, and (b) a positive photoresist composition containing a light-shielding material is applied on the transparent conductive layer to apply the light-shielding property. Forming a photoresist layer, and (c) exposing the photoresist layer through a photomask having a predetermined pattern and developing the photoresist layer to form a circuit, (d)
The transparent conductive layer exposed in the gap between the circuit-shaped photoresist layers is removed by etching to obtain a substrate on which a circuit-shaped laminate having the transparent conductive layer as a lower layer and the photoresist layer as an upper layer is formed, (E) The photoresist layer constituting the upper layer of the laminate is formed into strips by exposing the substrate through a photomask having a predetermined pattern and then developing, and if necessary, the formed photoresist layer is formed. The strip-shaped photoresist layer is subjected to heat treatment and / or light irradiation treatment, and (f) a photocurable resin composition containing a light-shielding material is applied onto the substrate to form a light-shielding resin layer, g)
The unexposed portion of the light-shielding resin layer is removed by exposing and developing from the back surface of the substrate, and together with or after the removal of the unexposed portion of the light-shielding resin layer in the steps (h) and (g), ( The photoresist layer formed in strips in step e) is removed to expose the surface of the transparent conductive layer, and (i) strip-shaped transparent exposed by electrodeposition using a thermosetting or photocurable resin material. A method for producing a color filter having a striped colored layer characterized by forming a colored layer on a conductive layer and having a light-shielding coating film in the gap, and using the color filter produced by the method A method for manufacturing a liquid crystal display device is provided.

The present invention will be described in detail below. As the transparent substrate used in the present invention, a conventionally known substrate such as a glass plate or a plastic plate can be exemplified. The step (a) in the present invention is a step of forming a transparent conductive layer on the entire surface or a predetermined range of the substrate. In this step, a transparent conductive layer such as an ITO film (tin-doped indium oxide film) or a Nesa film (antimony-doped tin oxide film) can be formed on the substrate by a known method. The step (b) in the present invention is a step of forming a light-shielding photoresist layer by applying a positive photoresist composition containing a light-shielding material on the transparent conductive layer formed in the step (a). In the positive photoresist composition containing the light-shielding material used in this step, the positive photoresist composition is exposed to light,
Any material can be used as long as it can elute and remove the exposed portion by development, and for example, a composition comprising a novolac type phenol resin and a quinonediazide-based photosensitizer is suitable. In addition, OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), PF-7
It can also be appropriately selected and used from commercially available products such as 400 (manufactured by Sumitomo Chemical Co., Ltd.) and FH-2030 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.).

The light-shielding material is not particularly limited,
Examples thereof include metal oxide black pigments, carbon black, bismuth sulfide, organic or inorganic pigments such as black dyes, and dyes. The positive photoresist composition containing a light-shielding material may further contain a viscosity modifier, an organic solvent, an adhesion improver, and other known auxiliary agents, if desired. In the positive photoresist composition containing the light-shielding material used in this step, the photoresist layer formed by applying the same is eluted by exposure and development in step (c) described below, and the photoresist layer is formed in step (g). When exposed from the back surface of the above, it functions as a photomask for the light-shielding resin layer formed on the upper layer in the step (f).

As a coating method, a screen printing method, an offset printing method, a roll coating method, a bar coating method, a spin coating method or the like can be used. Among these, when forming a coating film by the spin coating method, it is preferable to add a diluent (for example, a non-reactive diluent such as ethyl cellosolve acetate) to the positive photoresist composition to reduce the viscosity. , 5 to 40 parts by weight of the composition
It is particularly preferred to add parts by weight of diluent. In addition, the number of rotations in the spin coating method is two steps, and the first is 1
Spread on substrate at 00-400 rpm, then 800-50
It is recommended to make the film thickness uniform at 00 rpm. The spin coating method can form a coating film on the transparent conductive layer with high precision and fidelity. The light-shielding photoresist layer thus formed may have a temperature of 60 to 100 ° C.
Heat treatment is performed for 60 minutes. By heat treatment, the resin in the photoresist composition is pre-cured, and the adhesion between the coating film and the conductive layer is improved.

The step (c) in the present invention comprises the step (b)
The light-shielding photoresist layer formed in 1. is exposed through a photomask having a predetermined pattern, and then developed to dissolve and remove the exposed portion, leaving the unexposed portion as an insoluble portion, thereby forming a circuit layer of the photoresist layer. Is a step of forming. This step is a step for forming the transparent conductive layer formed on the transparent substrate into a plurality of transparent conductive circuits insulated from each other, together with the step (d) described later, and the pattern of the photomask is It can be appropriately determined according to the arrangement of the strip-shaped colored layers to be formed, for example, the arrangement of parallel, triangle, or mosaic. For the exposure in this step, light of various wavelengths can be used depending on the type of the positive photoresist composition used in step (b), but generally light of wavelength in the ultraviolet region is preferable,
A device using an ultra-high pressure mercury lamp, a metal halide lamp or the like as a light source can be used. The exposure conditions vary depending on the light source used and the type of positive photoresist composition, but the usual exposure amount is 10 to 4000 mJ / cm ^2.
Is. The development for removing the exposed portion is carried out by bringing it into contact with a drug (developing solution) having an appropriate dissolving power.
Such an agent is appropriately selected depending on the type of the positive photoresist composition, but is usually an alkaline aqueous solution obtained by dissolving caustic soda, sodium carbonate, a quaternary ammonium salt, an organic amine, or the like, or an ester, a ketone, It is appropriately selected from alcohols, ethers, organic solvents such as chlorinated hydrocarbons, and the like. The removal can be performed in about 5 seconds to 20 minutes by immersion or shower.
If necessary, rubbing with a brush or a woven cloth is used. After that, it is desirable to thoroughly wash with an organic solvent or water.

In step (d), the exposed portion is dissolved and removed in step (c), and the transparent conductive layer exposed in the gap between the photoresist layers formed in a circuit shape is removed by etching to remove the transparent conductive layer. This is a step of obtaining a substrate on which a circuit-shaped laminate, which is a lower layer and has a light-shielding photoresist layer as an upper layer, is formed on the surface. The transparent conductive layer can be easily removed by etching according to a conventional method. The chemical used for etching is appropriately selected depending on the type of the transparent conductive layer, and can be selected from, for example, mineral acids, organic acids or salts thereof.

In step (e), the substrate formed in step (d) is exposed through a photomask having a predetermined pattern and then developed to develop a light-shielding photoresist layer constituting an upper layer of the laminate. Is formed into a strip shape, and if necessary, the formed strip-shaped photoresist layer is subjected to heat treatment and / or light irradiation treatment. The photomask used in this step is patterned so that a portion corresponding to the strip-shaped photoresist layer to be formed is shielded from light and a portion corresponding to the gap is transmitted. Exposure and development can be performed in the same manner as in step (c). The photoresist layer thus formed into strips is subjected to heat treatment and / or light irradiation treatment, if necessary. The heat treatment is 100 to 300 ° C. for 1 to
The light irradiation treatment for 120 minutes can be performed under the condition of an exposure amount of 50 to 5000 mj / cm ² using light having a wavelength in the ultraviolet to far ultraviolet region. The order of performing both the heat treatment and the light irradiation treatment is not particularly limited. By performing such processing, the next step (f)
It is possible to prevent deformation and damage of the strip-shaped photoresist layer due to application of the photo-curable resin composition containing the light-shielding material and curing of the light-shielding resin layer in the step (h). The removal of the resist layer can be facilitated.

Step (f) is a step of forming a light-shielding resin layer by applying a photocurable resin composition containing a light-shielding material on the entire surface of the substrate obtained in step (e). The photocurable resin composition may be any one as long as it can elute and remove the light-shielding portion by exposure and development. For example, various resins such as acryl-based, urethane-based, epoxy-based, synthetic rubber-based, polyvinyl alcohol-based, or gelatin. And a composition comprising an azo compound as a photopolymerization initiator, a peroxide, a halide and the like. Further, a commercially available product as a negative photoresist composition such as OMR-83 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) or a commercially available product as a photocurable coating or ink can be appropriately selected and used. The light-shielding material mixed with such a photocurable resin composition is not particularly limited, but examples thereof include pigments such as metal oxide-based black pigments, carbon black, bismuth sulfide, and black dyes. In this case, an insulating dye may be preferable depending on the type of LCD used. The photocurable resin composition containing the light-shielding material may further contain a reactive diluent, a reaction initiator, a photosensitizer, an adhesion improver, an organic solvent for adjusting the viscosity, water, etc., if desired. You can The coating can be performed by a method such as a spin coating method, a roll coating method, a screen printing method, an offset printing method, and a dip coating method, and thus a uniform light-shielding resin layer can be formed.

The step (g) is a step of removing the unexposed portion of the light-shielding resin layer by exposing and developing from the back surface of the substrate having the light-shielding resin layer formed on the entire surface in the step (f). is there. Exposure in this step can use light with a wavelength in various ranges depending on the type of the photocurable resin composition, but in general, light with a wavelength in the ultraviolet region is preferable, and an ultrahigh pressure mercury lamp, a metal halide lamp or the like was used as a light source. It can be performed using the device. The exposure conditions vary depending on the light source used and the type of the photocurable resin composition, but the usual exposure amount is 100 to 4000 mJ / cm ² . The exposed portion undergoes a crosslinking reaction to become insoluble and hardens. In order to prevent polymerization inhibition due to oxygen in the air during exposure, the exposure may be performed in a nitrogen gas atmosphere, or the exposure may be performed by providing an oxygen barrier film containing polyvinyl alcohol as a main component. .

In this step, development is carried out to elute and remove the unexposed portion of the light-shielding resin layer. This removal is performed by contacting with a drug (developing solution) having an appropriate dissolving power and eluting. Such an agent is selected depending on the type of the photocurable resin composition, but is usually an alkaline aqueous solution obtained by dissolving caustic soda, sodium carbonate, a quaternary ammonium salt or an organic amine in water, or an ester or ketone.
It is appropriately selected from alcohols, organic solvents such as chlorinated hydrocarbons, and the like. Elution is by immersion or shower, etc. 3
It may be performed for 0 seconds to 5 minutes. After that, it is desirable to thoroughly wash with water, an organic solvent or the like.

Step (h) exposes the surface of the transparent conductive layer by removing the light-shielding photoresist layer which has been formed into strips in step (e) and which has been heated and / or irradiated with light as necessary. It is a process to do. Removal of the photoresist layer
In step (g), it may be performed together with the removal of the light-shielding resin layer, or may be performed after the removal of the light-shielding resin layer. The removal is carried out by contact with a drug having an appropriate dissolving power and peeling force. Such an agent is appropriately selected depending on the type of the positive photoresist composition, but is usually an alkaline aqueous solution obtained by dissolving caustic soda, sodium carbonate, a quaternary ammonium salt, an organic amine and the like in water,
Alternatively, ester, ketone, alcohol, ether,
It is appropriately selected from organic solvents such as chlorinated hydrocarbons.
Removal is 5 seconds to 2 by immersion or shower.
It can be done in about 0 minutes. Brush if necessary,
Rubbing with a woven cloth or a high pressure shower is used. After that, it is desirable to thoroughly wash with an organic solvent or water. In this step, the transparent conductive layer is exposed in strips, and the gap is filled with the light-shielding resin layer (light-shielding coating film) to form a substrate. The light-shielding resin layer forming the gap between the strips is, for example, at a temperature of 100 to 280 ° C. after the development in step (g) or the removal of the light-shielding photoresist layer in step (h). ~ 12
It is desirable to improve the strength of the coating film by heat treatment for 0 minutes.

Step (i) is a step of forming a colored layer on the transparent conductive layer exposed in step (g) by electrodeposition. The electrodeposition method performed in this step is generally known. The electrodeposition method includes an anion type and a cation type, and either method can be used in the present invention, but the anion type electrodeposition method is preferable because it has little influence on the circuit.

The resin material (binder) of the electrodeposition liquid used for electrodeposition is a thermosetting resin such as a maleinized oil type, an acrylic type, a polyester type, a polybutadiene type or a polyolefin type, or a resin thereof, for example. Examples thereof include photocurable resins obtained by half-esterifying a hydroxyl group-containing monomer having a (meth) acryloyl group such as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. These can be used alone or as a mixture. A dye having a desired hue such as a dye or a pigment is added to these binders. The electrodeposition liquid can generally be prepared by dispersing, dissolving and diluting components such as a binder and a dye in water. As the electrodeposition liquid, an electrodeposition liquid using an organic solvent other than water can also be used.

The substrate obtained through the above steps is placed in a bath containing an electrodeposition liquid, and in the case of the anion electrodeposition method, its conductive circuit serves as a positive electrode and a non-corrosive conductive material (stainless steel or the like). Is applied as a counter electrode and a DC voltage is applied, an electrodeposition coating film is selectively formed on the strip-shaped conductive layer located on the conductive circuit.

The thickness of the electrodeposition coating film can be controlled by the electrodeposition conditions. The electrodeposition condition is usually 10 to 300 V and 1
It is about 2 to 3 minutes. It is desirable that the electrodeposition coating film is thoroughly washed after forming the coating film to remove unnecessary substances. To increase the strength of the coating film, if necessary, 100 to 280 ° C, 10 to
The heat treatment can be performed for 120 minutes.

In this step, when electrodeposition is carried out using a photo-curable resin as the resin material, after the electrodeposition, for example, by exposing and developing from the back surface of the substrate in the same manner as in step (g), light shielding is performed. It is possible to remove the colored coating film that may be formed by electrodeposition on the light-shielding resin layer that is a conductive coating film.

Thus, a substrate having a strip-shaped colored layer and a light-shielding coating film in the gap can be prepared. The arrangement of strip-shaped colored layers varies depending on the type of LCD used, but for example, strips of red, green and blue colored layers are arranged in parallel, triangle or mosaic. To be done. According to the present invention, a desired arrangement can be obtained by appropriately selecting the pattern of the photomask used in step (c) and step (e). A color filter is manufactured using the substrate thus manufactured. The color filter can be manufactured according to a conventional method. For example, if necessary, an overcoat film (protective film) may be formed on the colored layer and the light-shielding coating film formed as described above, and if necessary, a transparent conductive film for liquid crystal driving may be formed thereon. According to the above, a color filter can be manufactured by forming a circuit pattern. A liquid crystal display device can be manufactured by a known method using the color filter manufactured by the method of the present invention.

An embodiment of forming a substrate having strip-shaped colored layers arranged in parallel and having a light-shielding coating film in the gap according to the method of the present invention will be described below with reference to the drawings.
1 (1) to 1 (7) are schematic views of a cross section of a substrate formed by the method of the present invention, and FIGS. 2 (1) and 2 (2) are schematic views of the plane thereof.

In step (a), ITO (In ₂ O ₃ + SnO) is formed on a transparent substrate 1 such as a glass substrate having a thickness of 1.1 mm.
₂ ) etc. to form a transparent conductive layer 2. [FIG. 1 (1)] In the step (b), for example, a light-shielding positive photoresist prepared by mixing FH-2030 (a positive photoresist composition manufactured by Fuji Hunt Electronics Technology Co., Ltd.) with a light-shielding material. The composition is applied on the transparent conductive layer 2 to form a light-shielding photoresist layer 3. [Fig. 1
(2)]

In step (c), a photomask having a stripe pattern, for example, a light-shielding portion width of 80 μm and a light-transmitting portion width of 20 μm is overlaid on the photoresist layer 3 and exposed according to a conventional method. The photoresist layer 3 is developed to form stripes (width 80 μm) and the surface of the transparent conductive layer 2 is exposed in the gap (width 20 μm). [Fig. 1 (3)]

In step (d), the portion of the transparent conductive layer 2 whose surface is exposed in step (c) is removed by etching according to a conventional method. In this step, the lower layer is formed on the substrate 1 by the transparent conductive layer 2
Is formed into a stripe-shaped laminated layer having a photoresist layer 3 as an upper layer. [Fig. 1 (4)]

In the step (e), for example, the photomask used in the step (c) in order to form the photoresist layer 3 constituting the upper layer of the stripe-shaped laminated layer formed in the step (d) into a strip shape. Are laminated in the direction perpendicular to the longitudinal direction of the laminate, and post-exposure development is performed according to a conventional method. In this way, the strip-shaped photoresist layer 3 is formed in which the surface of the substrate 1 is exposed in the vertical gap and the surface of the transparent conductive layer 2 is exposed in the horizontal gap, and the entire gap is in a lattice shape. [Fig. 2 (1)]

If necessary, light having a wavelength in the ultraviolet region of 1000 mj / cm ² is applied to the strip-shaped photoresist layer.
Irradiation and then heat treatment at 100 ° C. for 10 minutes. Then, in step (f), a negative photoresist composition containing a light-shielding material is applied to the entire surface of the substrate, and if necessary, heat treatment is performed at 100 ° C. for 10 minutes to pre-cure it.
The light blocking resin layer 4 is formed. [Fig. 1 (5)]

In step (g), the back surface of the substrate 1 is exposed and developed by a conventional method to remove the unexposed portion of the light-shielding resin layer 4, and then heat-treated at, for example, 230 ° C. for 30 minutes to remain after development. The curing of the light shielding resin layer 4 is completed. Subsequently, in step (h), the strip-shaped photoresist layer 3 formed in step (e) is removed by a conventional method.
In this way, a substrate is formed in which the surface of the transparent conductive layer 2 is exposed in the form of strips and the lattice-shaped gaps are filled with the light-shielding resin layer. [Fig. 1 (6)]

Then, in step (i), the transparent conductive layer 2 on the substrate 1 is used as one electrode for electrodeposition according to a conventionally known electrodeposition method to color the transparent conductive layer exposed in strips. Layer 5
To form. In this way, it is possible to industrially form a substrate having a strip-shaped colored layer and precisely filling the lattice-shaped gaps with the light-shielding coating film. [The cross section of the formed substrate is shown in FIG. 1 (7), and the plane is shown in FIG. 2 (2). still,
In the figure, R represents a red colored layer, G represents a green colored layer, and B represents a blue colored layer. ]

[0030]

According to the method of the present invention, a striped colored layer and a light-shielding coating film for filling the gap between the striped colored layer and the gap are accurately formed, light leakage is well prevented, and coloring is clear and excellent in optical characteristics. The filter can be manufactured industrially advantageously, and a high quality liquid crystal display device can be manufactured using the filter.

[Brief description of drawings]

FIG. 1 is a schematic view of a cross section of a substrate having a shape formed in each step of the present invention.

FIG. 2 is a schematic plan view of a substrate having a shape formed in each step of the present invention.

[Explanation of symbols]

 1 Transparent Substrate 2 Transparent Conductive Layer 3 Light-Shielding Photoresist Layer 4 Light-Shielding Resin Layer 5 Coloring Layer R Red Coloring Layer G Green Coloring Layer B Blue Coloring Layer

Claims (4)

[Claims] 1. A light-shielding photoresist layer comprising: (a) forming a transparent conductive layer on a transparent substrate; and (b) coating a positive photoresist composition containing a light-shielding material on the transparent conductive layer. And (c) the photoresist layer is exposed through a photomask having a predetermined pattern and then developed to form a circuit, and (d) the photoresist layer is exposed in a gap between the photoresist layers. The transparent conductive layer is removed by etching to obtain a substrate on which a circuit-like laminate having the transparent conductive layer as a lower layer and the photoresist layer as an upper layer is formed. (E) The substrate having a predetermined pattern After exposure through a mask, development is performed to form the photoresist layer forming the upper layer of the laminate into strips, and if necessary, the striped photoresist layer is subjected to heat treatment. And / or light irradiation treatment, (f) applying a photocurable resin composition containing a light-shielding material onto the substrate to form a light-shielding resin layer, (g) exposing and developing from the back surface of the substrate By removing the unexposed portion of the light-shielding resin layer, and (h) with the removal of the unexposed portion of the light-shielding resin layer in the step (g), or after removing the strip-shaped in the step (e) The surface of the transparent conductive layer is exposed by removing the photoresist layer formed in step (i), and a colored layer is formed on the strip-shaped transparent conductive layer exposed by electrodeposition using a thermosetting or photocurable resin material. A method for producing a color filter having a strip-shaped colored layer having a light-shielding coating film in a gap between the colored layers. 2. The strip-shaped photoresist layer is heat-treated and / or light-irradiated in the step (e).
The method described in. 3. The method according to claim 1, wherein in the step (i), electrodeposition is performed using a photocurable resin material. 4. A method of manufacturing a liquid crystal display device, which comprises using the color filter manufactured by the method according to claim 1.