KR101357333B1 - Photosensitive resin composition and black matrix thereof - Google Patents

Abstract

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition used for light shielding in a liquid crystal display device and a black matrix using the same. It provides a photosensitive resin composition comprising a high refractive index inorganic material nano-dispersion as described above, can reduce the light transmittance and increase the optical density after the pattern development, even if the high refractive index inorganic material dispersion suitable adhesive strength In addition, the storage stability of the liquid solution is also excellent, it is possible to implement the ultra-thin device of the liquid crystal display panel and to accelerate the implementation of light, small and thin functional display device, such as a flexible display (Flexible display).

Description

Photosensitive resin composition and black matrix using the same

1 illustrates an example of a state in which the photosensitive resin composition of the present invention is applied to a substrate and irradiated with active rays to cure the same.

* Explanation of the main symbols in the drawings

10 glass substrate 20 photosensitive film

30: highly refractive inorganic material 40: black pigment

 The present invention relates to a photosensitive resin composition used for light shielding in a liquid crystal display device and a black matrix using the same.

 Liquid crystal displays are devices that display text or images by transmitting or blocking light by controlling an electric field applied to a liquid crystal material having dielectric anisotropy. An electroluminescent (EL) device, a cathode ray tube (CRT), and a light emission Unlike a display device that generates light internally, such as a diode (LED), the LCD uses an external light source.

Such liquid crystal displays have advantages such as light weight, thinness, low cost, low power consumption, and excellent integrated circuit bonding, and are widely used for display panels of laptop computers and pocket computers and color TV images for vehicle loading. have. Such a liquid crystal display device includes a lower substrate on which a black matrix, a color filter, and an indium tin oxide (ITO) pixel electrode are formed, an active circuit unit consisting of a liquid crystal layer, a thin film transistor, and a capacitor capacitor layer, and an upper substrate on which an ITO pixel electrode is formed. It is configured by.

The color filter used in the conventional liquid crystal display device has a black matrix and red, green, and blue color layers repeated on a plastic or glass substrate, and a poly filter is used to maintain the color filter protection and surface smoothness. An overcoat layer having a thickness of 1 to 3 μm and a layer of an ITO transparent conductive layer to which a voltage for driving a liquid crystal is applied are formed on the overcoat layer.

Here, the black matrix serves to improve contrast by blocking uncontrolled light transmitted through the transparent pixel electrode of the substrate, and the red, green, and blue colored layers transmit light of a specific wavelength among white light to express colors. The transparent conductive film layer serves as a common electrode for applying an electric field to the liquid crystal.

Among them, the black matrix may be made of chromium or made of resin. However, when chromium is used, it has excellent shading performance, environmental resistance, and chemical resistance, but has a problem of requiring a separate treatment process for total reflection due to its complicated process and high equipment cost, and high reflectance. Black Matrix is being actively researched.

In general, the substrate of the color filter can be manufactured by a method such as dyeing, printing, pigment dispersion, electrodeposition, etc., the black matrix is mainly produced by the pigment dispersion method. The pigment dispersion method is a color filter by coating a photosensitive resin composition containing a colorant on a transparent substrate provided with a black matrix, exposing the pattern of the form to be formed, and then removing a non-exposed portion with a solvent and thermally curing the color filter by repeating a series of steps. It is a method of manufacturing. This pigment dispersion method is used in the manufacture of the black matrix has the advantage of improving the heat resistance and durability, which is the most important property of the color filter and maintaining the thickness of the film uniformly.

The black matrix produced by the pigment dispersion method is largely composed of two components: a polymer compound, ie, a binder resin, and a photopolymerizable monomer that reacts with light during exposure to form a photoresist to maintain a constant thickness and support role. And a photosensitive resin composition containing a pigment, a photoinitiator, a solvent and other additives in addition to the above components. The binder resin used in the pigment dispersion method is a polyimide resin, a photosensitive resin composed of an acrylic polymer and an azide compound, a phenol resin, and the like, and a resin obtained by reacting a bisphenol fluorene type epoxy acrylate resin with an acid anhydride. Also disclosed are a method of manufacturing a color filter using a binder resin.

Recently, research on lighter and thinner display materials has been actively conducted at the request of light and small display devices of LCD and color filter manufacturers. Therefore, researches to improve the properties of resistance, conductivity, optical density, etc. by changing the surface structure and material properties of carbon black and titanium black millbase, which are the basis of photosensitive resin materials, have been conducted. In order to improve the material properties by using the structure and additives of the binder added during the formulation process, much research is being actively conducted.

However, such an attempt may cause a problem that the degree of cure of the pattern after the post bake process, which is performed in the unit process by changing the structural change of the material, may be a cause of poor reliability in the harsh conditions of the post process.

The present invention is to solve the above problems, further comprising an inorganic material with a high effective refractive index during the liquid-liquid process in the photosensitive resin composition comprising a binder resin for the formation of a black matrix, thereby improving the optical density of the cured black matrix It has been found that the present invention can be completed.

Therefore, an object of the present invention is to disperse the inorganic material having a high refractive index during the liquid-liquid process of the photosensitive resin to improve the light shielding characteristics of the LCD that has undergone the color filter process, showing the desirable adhesive strength and excellent storage stability, such as thin displays, such as next-generation displays. It is providing the photosensitive resin composition useful for formation of a black matrix.

Another object of the present invention is to provide a black matrix using the composition.

The present invention for achieving the above object is a black matrix photosensitive resin composition for a liquid crystal display comprising a binder resin, a photopolymerization initiator, a black pigment, a solvent, characterized in that it comprises a highly refractive inorganic nano dispersion having a refractive index of 1.5 or more. It provides the photosensitive resin composition.

The high refractive inorganic material is characterized in that it comprises 0.5 to 10% by weight.

The high refractive inorganic material is TiO ₂ sol, SrTiO ₃ sol, ZnS, ZnSe, potassium bromide, AgCl, MgO, cesium iodide, cesium bromide, CaCO ₃ , phosphorus tribromide, phenyltrichloride, trichroman-4 Trionroman-4-one, thionyl bromide, ZnO ₂ , CeO ₂ , ITO sol, Ta ₂ O ₅ , Ti ₂ O ₅ , Ti ₂ O ₃ , ZrO ₂ , Br ₂ , CS ₂ , ZrO _2- It is characterized in that at least one selected from TiO ₂ sol and SiO ₂ -Fe ₂ O _{3 type} compound.

The binder resin is characterized in that the resin selected from acrylic resin, polyimide resin, phenol resin and cardo resin.

The present invention also provides a black matrix for liquid crystal display comprising the photosensitive resin composition.

The black matrix has an optical density of 4.5 or more per unit thickness (1 μm).

Hereinafter, the present invention will be described in more detail.

<Binder Resin>

In the photosensitive resin composition of this invention, resin selected from acrylic resin, polyimide resin, phenol resin, and cardo resin is used as binder resin.

In general, when the molecular weight is low, the development speed is increased by the swelling phenomenon of the pattern after UV curing, whereas when the molecular weight is increased, the development time may be delayed. The molecular weight of the binder resin is about 3000 to 15000, which has a suitable starting point (breaking point) and is good in that a stable process condition can be obtained by maintaining a constant process window during the developing process. , And the content thereof is preferably 5 to 25% by weight in the total photosensitive resin composition in consideration of the dispersibility of the inorganic substance, the developability of the pattern, the sensitivity stability, and the like.

<Polyfunctional monomer>

The polyfunctional monomer which can be used in the photosensitive resin composition of this invention is a polyfunctional acrylate type monomer normally used, Specifically, ethylene glycol diacrylate, triethylene glycol diacrylate, 1, 3- butanediol diacryl Rate, tetramethylene glycol diacrylate, propylene glycol diacrylate, 1,4-cyclohexanediol diacrylate, trimethylol triacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, tetraethylene glycol di Acrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, sorbitol triacrylate, sorbitol tetra acrylate, sorbitol pentacrylate, sorbitol hexaacrylate, tetramethylene glycol dimethacrylate, triethylene glycol Dimethacryl , Trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, trimethylolethane trimethacrylate, 1,3-butanedioldimethacrylate, pentaerythritol dimethacrylate, dipentaerythritol dimethacrylate Latex, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxy-propoxy) phenyl] dimethylmethane, bis [p- (methacryloxy-epoxy) phenyl] dimethylmethane, Sorbitol trimethacrylate, Sorbitol tetramethacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, isobonyl Acrylate, n-vinylpyrrolidone, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate , Tripropylene glycol diacrylate, polyethylene glycol diacrylate, pentaerythritol diacrylate, dipentaerythritol hexaacrylate, tetrahydrofurfuryl methacrylate, glycidyl acrylate, pentaerythritol tetraacrylate , Vinyl acetate, triallyl cyanurate, and the like can be used. In addition to these monomers, prepolymers such as dimers and trimers can also be used effectively.

As for the content of such a polyfunctional monomer, 0.5-5 weight% is preferable in all the photosensitive resin compositions. If the content is less than 0.5% by weight, there is a disadvantage in that the thermal decomposition temperature of the photosensitive material is low, and when the content is more than 5% by weight, there is a problem of poor storage.

<Photopolymerization initiator>

In the photosensitive resin composition of this invention, a photoinitiator is used normally, For example, 2,2'- diethoxy acetophenone, 2,2'- diethoxy acetophenone, 2-hydroxy-2-methylpropy Ophenone, pt-butyltrichloroacetophenone, pt-butyldichloroacetophenone, benzophenone, 4-chloroacetophenone, 4,4'-dimethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3 ' -Dimethyl-2-methoxybenzophenone, 2,2'-dichloro-4-phenoxyacetophenone, 2-methyl-1- (4-methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1one, etc. are mentioned.

Usually, a photoinitiator is contained in 0.5 to 7 weight% of the whole photosensitive resin composition.

<Black Pigment>

In the photosensitive resin composition of the present invention, the black pigment is not particularly limited, and for example, aniline black, perylene black, titanium black, carbon black, and the like can be used, and anthraquinone pigments, phenylene pigments, etc. can be used as color correction agents. Organic pigments, such as a condensed polycyclic pigment, a phthalocyanine pigment, and an azo pigment, can be used. Such black pigment is included in 5 to 30% by weight of the total photosensitive resin composition.

<High refractive inorganic material>

The photosensitive resin composition of this invention contains the highly refractive inorganic material.

High refractive inorganic materials can enhance the total reflectance of incident light sources and ultimately increase the optical density of the black matrix.

The high refractive index inorganic material has a refractive index of 1.5 or more, TiO ₂ sol (n = 2.616), SrTiO ₃ sol (n = 2.445), ZnS (n = 2.25), ZnSe (n = 2.44), potassium bromide (n = 1.6 ), AgCl (n = 2.09), MgO (n = 1.726), Cesium Iodide (n = 1.75), Cesium Bromide (n = 1.708), CaCO ₃ (n = 1.658), Phosphorus Tribromide ( n = 1.697), phenyltrichloride (n = 1.586), trichroman-4-one (Thiochroman-4-one, n = 1.6395), thionyl bromide (n = 1.675), ZnO ₂ , CeO ₂ , ITO sol, Ta ₂ O ₅ , Ti ₂ O ₅ , Ti ₂ O ₃ , ZrO ₂ , Br ₂ (n = 1.66), CS ₂ (n = 1.63), ZrO ₂ -TiO ₂ based sol, SiO ₂ -Fe ₂ O ₃ -based compounds and the like, and nano dispersions or nano particles thereof are included.

The nano-dispersion refers to a dispersion of nanoparticles having a particle size of 3 to 200 nm in various media, and means that the nanoparticles have a particle size of 3 to 200 nm.

It is preferable that the said high refractive inorganic material is 0.5 to 10 weight% of all the photosensitive resin compositions. If the content is less than 0.5% by weight in the total photosensitive resin composition, the deviation from the refractive index when not used is small, and the total reflection characteristic of the optical density improvement does not appear, and there is no change in the optical density. On the contrary, if the content exceeds 10% by weight, it may act as a reaction impurity together with the carbon particles of the carbon black mill base in the final prepared composition, which may cause a problem of deterioration of adhesion and storage stability, and after development, residues and protrusions on the black matrix pattern This can cause problems such as problems such as pattern straightness and developability.

<Solvent>

In the present invention, as the solvent, those commonly used may include, for example, ethylene glycol acetate, ethyl cellosolve, propylene glycol methyl ether acetate, ethyl lactate, polyethylene glycol, cyclohexanone, propylene glycol methyl ether, and the like. It can select from a solvent and can use individually or in mixture. Since the proportion of the solvent used in the present invention may vary depending on the photosensitive resin composition, the content thereof cannot be specifically defined, but it is preferable to select the proportion of the solvent so that the resin solution has a viscosity that can be applied to the substrate. Typically the content is from 50 to 88% by weight of the total resin composition.

<Others>

In the present invention, an adhesion promoter may be further added in consideration of adhesion. For example, Shinetsu Co., Ltd., KBM-403 (GPTMS, 3-glycidoxy propyl trimethoxy silane), KBE-603 (N-2 (aminoethyl) 3-amino propyl triethoxy silane), and the like. In the case of including such an adhesion promoter, it is preferable to add 0.1 to 0.5% by weight of the entire photosensitive resin composition.

In addition, a dispersant may be used in consideration of the desired dispersion in dispersing the pigment in the mixture, it may be used by adding the inside of the pigment in the form of surface treatment in advance, or may be used by the method of external addition to the pigment. Such dispersants may include nonionic, anionic or cationic dispersants, specific examples of which are polyalkylene glycols and esters thereof, polyoxyalkylene polyalcohol ester alkylene oxide adducts, alcohol alkylene oxide adducts, Phonic acid ester, sulfonate, carboxylic acid ester, carboxylate, alkylamide alkylene oxide adduct, alkylamine, etc. are mentioned. These may be added alone or in combination of two or more.

In addition, other additives such as surfactants, antioxidants, stabilizers and the like can be added to the composition of the present invention within a range that does not impair the physical properties of the composition.

The photosensitive resin composition thus obtained can be used for producing the black matrix for color filters of the liquid crystal display device. When manufacturing a black matrix using the photosensitive resin composition of this invention, the photosensitive resin composition is apply | coated to 0.5-10 micrometer thickness on the glass substrate for color filters using a suitable method, such as spin coating, roller coating, and spray coating. And soft bake at 90 to 120 ° C. Then, the active line is irradiated to form a pattern required for the color filter. As the light source used for the irradiation, UV of 190 to 450 nm, preferably 200 to 400 nm is used, and electron beam and X-ray irradiation are also suitable. After the irradiation, when the coating layer is treated with a developing solution, the unexposed portions of the coating layer are dissolved and a pattern necessary for the color filter is formed. This process can then be repeated according to the number of colors required to obtain a color filter with the desired pattern.

1 illustrates an example of a state in which the photosensitive resin composition of the present invention is applied to a substrate and irradiated with active rays to cure the same.

After curing, the photosensitive resin composition in which the highly refractive inorganic material 30 is dispersed increases, thereby increasing the refractive index of the entire photosensitive resin composition. When light is incident, the total reflection frequency is increased by the highly refractive inorganic material 30. As the frequency of total reflection increases, the light blocking effect of the photosensitive resin composition increases, resulting in a decrease in the light transmittance.

The relationship between the light transmittance and the optical density is expressed as in Equation 1 below, and it can be seen that it is inversely proportional.

<Formula 1>

Accordingly, in the case of the photosensitive resin composition of the present invention, the absorption and the reflection coefficient of incident light are increased to enable the production of the photosensitive resin composition for a high-functional display having a high optical density.

This enables the manufacture of ultra-thin display devices having high optical properties and at the same time accelerates the implementation of lighter, smaller and thinner functional devices such as flexible displays. In particular, it is useful as a resin composition for black matrix formation, such as a flexible display which requires mild hardening conditions.

It is also useful as a photosensitive resin composition of PDP, passivation, dry film photoresist and other organic semiconductors.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

&Lt; Example 1 >

25 weight% of binder resin copolymerized with 9.9-bis- (4-hydroxyphenyl) fluorene and an epoxy resin to react with acid anhydride, 32 weight% of carbon black, 30 weight% of PGMEA as a solvent, 5 weight% of polyfunctional monomers, photopolymerization 3% by weight of initiator, 2% by weight of Shin-Etsu Co., Ltd. KBM-403, and 3% by weight of TiO ₂ (n = 2.616) nanodispersion were dispersed as a highly refractive inorganic material to prepare a photosensitive resin composition.

<Example 2>

As a highly refractive inorganic material, AgCl (n = 2.09) nanodispersions were dispersed and used, and the others were carried out in the same manner as in Example 1.

<Example 3>

Thiochroman-4-one (n = 1.6395) was added as a highly refractive inorganic material, and the others were carried out in the same manner as in Example 1.

<Example 4>

Thionyl Bromide (n = 1.675) was added as a highly refractive inorganic material, and the others were carried out in the same manner as in Example 1.

&Lt; Example 5 >

Potassium Bromide (n = 1.6) nanoparticles were dispersed as a highly refractive inorganic material, and the others were carried out in the same manner as in Example 1.

 <Example 6>

25% by weight of acrylic copolymer binder resin, 32% by weight of carbon black, 30% by weight of PGMEA as solvent, 5% by weight of polyfunctional monomer, 3% by weight of photopolymerization initiator, KBM-403, 2% by weight of Shinetsu as adhesion promoter, high refractive index dispersing TiO ₂ (n = 2.616) 3% by weight of a nano-dispersion as the inorganic material and to the crude liquid photosensitive resin composition.

 &Lt; Example 7 >

25% by weight of acrylic copolymer binder resin, 32% by weight of carbon black, 30% by weight of PGMEA as solvent, 5% by weight of polyfunctional monomer, 3% by weight of photopolymerization initiator, KBM-403, 2% by weight of Shinetsu as adhesion promoter, high refractive index AgCl (n = 2.09) nanodispersion is dispersed by 3% by weight as an inorganic material to prepare a photosensitive resin composition.

&Lt; Example 8 >

0.2 wt% of TiO ₂ (n = 2.616) nanodispersant was added as the highly refractive inorganic material, and other conditions were carried out in the same manner as in Example 1.

&Lt; Example 9 >

12 wt% of AgCl (n = 2.09) nanodispersion was added as the highly refractive inorganic material, and other conditions were performed in the same manner as in Example 1.

&Lt; Comparative Example 1 &

Evaluation was performed using BK-4707SL manufactured by TOK. This material does not use high refractive inorganic material.

Comparative Example 2

Evaluation was performed using BK-4700 as a general photosensitive resin composition manufactured by TOK. This material does not use high refractive inorganic material.

&Lt; Comparative Example 3 &

25 weight% of binder resin copolymerized with 9.9-bis- (4-hydroxyphenyl) fluorene and an epoxy resin to react with acid anhydride, 32 weight% of carbon black, 30 weight% of PGMEA as a solvent, 5 weight% of polyfunctional monomers, photopolymerization 3% by weight of initiator, 2% by weight of Shin-Etsu Co., Ltd. KBM-403 as an adhesion promoter, and 3% by weight of Lithium Fluoride (n = 1.35) nanodispersant as a highly refractive inorganic material were prepared to prepare a photosensitive resin composition.

&Lt; Comparative Example 4 &

Pottasium Chloride (n = 1.49) nanodispersion was added as a highly refractive inorganic material, and other conditions were performed in the same manner as in Comparative Example 4.

<Experimental Example>

The photosensitive resin composition prepared according to the above Examples and Comparative Examples was prepared through the following photolithography process and evaluated.

In the photolithography process, first, each of the photosensitive resin compositions was spin-coated on a glass substrate for color filters to apply a thickness of 1.2 μm. In order to form the pattern required for the color filter thus obtained, ultraviolet rays were used as the light source and irradiated with active rays. The irradiation dose at this time was 75mJ. Then, the coating layer was developed by alkaline developer (KOH) to dissolve the unexposed portions of the coating layer and to form a pattern required for the color filter.

1) Optical Density

The optical density is 30 minutes post-baked photosensitive resin composition on the glass substrate developed at 25 ℃ in a 200 ℃ convection oven, using MCPD 3000 colorimeter and PMT (Photo Multiplier Tube, Otsuka Electronics) The transmittance was measured at a wavelength of 550 nm, and the optical density was measured by the formula of Formula 1.

2) adhesive strength

Cross-cutting Tape Test was conducted using ASTM D3359 method and the elcometer was used.

3) Storage stability

Storage stability was calculated by measuring the viscosity and particle size every 10 hours in the image storage state of 5 ℃ to calculate the date when the range of ± 2% of the initial value.

Optical density, adhesive strength and storage stability measurement results are shown in Table 1 below.

division Optical Density (/ ㎛) Adhesive strength Storage stability (days) Example 1 5.22 5B (100%) 100 Example 2 5.12 5B (100%) 95 Example 3 4.92 5B (100%) 91 Example 4 4.99 5B (100%) 102 Example 5 4.91 5B (100%) 92 Example 6 5.03 5B (100%) 99 Example 7 4.99 5B (100%) 97 Example 8 4.01 5B (100%) 106 Example 9 5.27 4B (90%) 80 Comparative Example 1 3.90 5B (100%) 95 Comparative Example 2 3.50 5B (100%) 93 Comparative Example 3 3.71 5B (100%) 95 Comparative Example 4 3.82 5B (100%) 100

From the results of Table 1 above, when the photoresist composition containing the binder resin according to the present invention further comprises a high refractive index inorganic material, the optical density after the photoresist pattern obtained is 4.5 or more per unit thickness (μm), It can be seen that the optical density is significantly increased. In addition, even in mild curing conditions, good adhesion strength can be obtained, and additional monomers have been added, but it can be seen that the storage stability of the photosensitive resin composition is also appropriate.

As described in detail above, as a result of dispersing a highly refractive inorganic material in a photosensitive resin composition comprising a binder resin according to the present invention, it is possible to increase the optical density by lowering the light transmittance after pattern development, such a highly refractive inorganic material Even though it has been dispersed, it has suitable adhesive strength and storage stability of liquid solution is also excellent, so that it is possible to realize ultra-thin device of liquid crystal display panel and to accelerate the implementation of light, small and thin functional display device such as flexible display. Invention.

Claims (6)

In the black matrix photosensitive resin composition for liquid crystal displays containing a binder resin, a photopolymerization initiator, a black pigment, and a solvent, TiO ₂ sol, SrTiO ₃ sol, ZnS, ZnSe, potassium bromide, AgCl, MgO, cesium iodide, cesium bromide, CaCO ₃ , phosphorus tribromide, phenyltrichloride, trichroman-4-one (Triochroman-4 -one), thionyl bromide, ZnO ₂ , CeO ₂ , Ta ₂ O ₅ , Ti ₂ O ₅ , Ti ₂ O ₃ , ZrO ₂ , Br ₂ , CS ₂ , ZrO ₂ -TiO ₂ based sol and SiO ₂ -Fe _It contains at least one high refractive inorganic material selected from ₂ O _{3 type} compound, The photosensitive resin composition characterized by the optical density after obtaining a photoresist pattern 4.5 or more per unit thickness (micrometer). The method of claim 1, The highly refractive inorganic material is 0.5 to 10% by weight of the photosensitive resin composition characterized in that it comprises. delete The method of claim 1, The binder resin is a photosensitive resin composition, characterized in that the resin selected from acrylic resin, polyimide resin, phenol resin and cardo resin. The black matrix for liquid crystal display containing the photosensitive resin composition of any one of Claims 1, 2, and 4. delete

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