JP7591391B2 - White photosensitive resin composition, color filter and image display device produced using the same - Google Patents

Description

The present invention relates to a white photosensitive resin composition, a color filter manufactured using the same, and an image display device.

A color filter is a thin-film optical component that can extract the three colors red, green, and blue from white light and create minute pixel units, with each pixel measuring tens to hundreds of micrometers. Such color filters have a structure in which a black matrix layer formed in a predetermined pattern on a transparent substrate is stacked in order to block the boundaries between each pixel, and pixel sections in which the three primary colors (usually red (R), green (G), and blue (B)) are arranged in a predetermined order to form each pixel are stacked in sequence.

Recently, one method for creating color filters has been the pigment dispersion method, which uses pigment-dispersed photosensitive resins. However, as the light emitted from the light source passes through the color filter, some of the light is absorbed by the color filter, reducing the light efficiency. In addition, problems have arisen in that color reproduction is reduced due to the characteristics of the pigments contained in the color filter.

In particular, as color filters are used in a variety of fields, including various image display devices, there is a demand for not only excellent pattern characteristics, but also high color reproduction rate as well as other performance factors such as high brightness and high contrast ratio. In order to solve these problems, a method for manufacturing a color filter using a spontaneous light-emitting photosensitive resin composition containing quantum dots has been proposed.

For example, Korean Patent Registration No. 10-1906279 discloses a photosensitive resin composition containing quantum dots, a binder resin, a photopolymerizable monomer, a photopolymerization initiator, a diffusing agent, a polymerization inhibitor, a thiol-based additive, and a solvent, as well as technology relating to a color filter using the same.

However, as in the above patent document, in the case of a color filter containing quantum dots, the performance of the color conversion panel may be somewhat degraded as the efficiency of the quantum dots, especially the efficiency of blue quantum dots, decreases, and in the case of blue quantum dots, they are expensive, which increases the overall manufacturing cost.

In the case of a display including a color conversion panel using a blue light source, green and red pixels use green and red quantum dots to display colors, respectively. However, as mentioned above, blue is difficult to use due to performance issues with blue quantum dots, so blue light sources are transmitted to display colors. For this reason, green and red result in scattered light by the quantum dots, while blue results in direct light, making it difficult to mix colors clearly when mixing colors. To solve this problem, technology has been developed to introduce a scattering layer for the purpose of scattering into blue pixels.

Therefore, there is a need for the development of a photosensitive resin composition that can prevent a decrease in efficiency of blue pixels, prevent residues, provide excellent reliability, and at the same time reduce manufacturing costs.

Korean Patent No. 10-1906279

One objective of the present invention is to provide a white photosensitive resin composition suitable for manufacturing pixel layers that can provide excellent reliability without causing residue problems while preventing a decrease in efficiency of blue pixels.

The present invention also aims to provide a color filter including a coating film produced using the white photosensitive resin composition, and an image display device including the color filter.

The present invention relates to a light-emitting device comprising: (A) scattering particles; (B) an alkali-soluble resin; (C) a polymerizable compound; (D) a photopolymerization initiator; and (E) a solvent,
The alkali-soluble resin (B) includes a unit represented by the following formula 1 and a unit represented by the following formula (2),

In the above formula 1, R ₁ is a direct bond or a linear or branched divalent organic group having 1 to 6 carbon atoms;
* denotes a bond.

In the formula 2, _R2 is a divalent organic group having a direct bond and 1 to 20 carbon atoms, which may or may not contain a heteroatom;
* denotes a bond.

The present invention also provides a color filter including a coating film produced from the white photosensitive resin composition.

The present invention also provides an image display device that includes the color filter.

The white photosensitive resin composition of the present invention contains a specific alkali-soluble resin, which prevents the generation of residues in non-exposed areas during the production of the coating film and provides excellent heat resistance, as well as preventing a decrease in efficiency of blue pixels and reducing production costs. In addition, when the white photosensitive resin composition of the present invention is used, the transmission intensity can be improved.

Therefore, a color filter including a coating film produced using the above-mentioned white photosensitive resin composition and an image display device including the color filter can provide excellent effects in terms of image quality, viewing angle, durability, reliability, etc.

FIG. 1 is a diagram showing the criteria for evaluating residues in the experimental examples of the present invention. FIG. 2 illustrates a color filter structure according to one implementation of the present invention.

The present invention provides a white photosensitive resin composition comprising (A) scattering particles, (B) an alkali-soluble resin, (C) a polymerizable compound, (D) a photopolymerization initiator, and (E) a solvent, the alkali-soluble resin (B) comprising a structural unit of a specific chemical formula, and a color filter and an image display device including a coating film produced using the same.

In this specification, the term "organic group" refers to a group that essentially contains a carbon atom, and can be used to encompass both saturated and unsaturated groups.

The components constituting the white photosensitive resin composition of the present invention are described in detail below. However, the present invention is not limited to these components.

<White photosensitive resin composition>
The white photosensitive resin composition according to the present invention contains scattering particles, an alkali-soluble resin, a polymerizable compound, a photopolymerization initiator and a solvent, and may further contain optional additives as necessary.

(A) Scattering Particles The white photosensitive resin composition according to the present invention contains scattering particles to provide the effect of light scattering.

The white photosensitive resin composition of the present invention containing the scattering particles can be suitably used to manufacture blue pixels using a blue light source.

In the present invention, the scattering particles include a metal oxide.
The metal oxide may include one or more oxides selected from the group consisting of Li, Be, B, Na, Mg, Al, Si, K, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, Rb, Sr, Y, Mo, Cs, Ba, La, Hf, W, Tl, Pb, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Ti, Sb, Sn, Zr, Nb, Ce, Ta, In, and combinations thereof.

For example, the metal oxide may include _one or more selected from the group consisting _{of Al2O3} , _SiO2 , ZnO, _ZrO2 , _BaTiO3 , _TiO2 , _{Ta2O5 , Ti3O5} , ITO, IZO, ATO, ZnO- _Al , _Nb2O3 , SnO, MgO, and combinations thereof, and if necessary, a material that has been surface-treated with a compound having an unsaturated bond, such as an acrylate, can also be used.

The scattering particles may have a limited average particle size and a limited content in the total composition so as to maximize the luminous intensity of the color filter.

In the present invention, the "average particle size" may be the number-average particle size, which can be determined, for example, from an image observed with a field emission scanning electron microscope (FE-SEM) or a transmission electron microscope (TEM). Specifically, it is obtained by extracting several samples from the FE-SEM or TEM observation images, measuring the diameters of these samples, and taking the arithmetic average value.

For example, the metal oxide contained in the scattering particles of the present invention may have an average particle size of 30 to 500 nm, preferably 30 to 300 nm. When the average particle size of the metal oxide satisfies the above range, the scattering effect is increased, and the white photosensitive resin composition containing the scattering particles can act as a blue pixel by a blue light source, which is preferable. In addition, the phenomenon of sinking in the composition is prevented, and a surface of uniform quality is obtained, so the average particle size can be appropriately adjusted within the above range.

The scattering particles may be included in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, and more preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the total of the photosensitive resin composition. When the scattering particles are included within the above range, there is an advantage that scattering pixels having excellent luminescence intensity can be manufactured. Specifically, when the scattering particles are included within the above range, there is an advantage that the desired luminescence intensity can be easily secured and a decrease in the stability of the composition can be suppressed.

On the other hand, the white photosensitive resin composition of the present invention is used for manufacturing blue pixels through which a blue light source can be transmitted as is, i.e., scattering pixels. The white photosensitive resin composition of the present invention preferably does not substantially contain a colorant in order to improve the transmission efficiency of blue light, but it is also possible to contain a small amount of a colorant in addition to the above-mentioned scattering particles, if necessary, taking into account other properties required of the composition.

When the white photosensitive resin composition of the present invention contains a small amount of a colorant, the colorant may be a blue colorant. Examples of the blue colorant include, but are not limited to, C.I. Pigment 15:6.

(B) Alkali-soluble resin The alkali-soluble resin (B) has reactivity due to the action of light or heat and alkali solubility, and can also act as a dispersion medium for solids such as scattering particles, and can be used selectively to perform the function of a binder resin.

In the present invention, the alkali-soluble resin (B) contains a unit represented by the following chemical formula 1 and a unit represented by the following chemical formula (2).

In the above formula 1, R ₁ may be a direct bond or a straight or branched divalent organic group having 1 to 6 carbon atoms, and * represents a bond.

Examples of the linear or branched divalent organic group having 1 to 6 carbon atoms represented by R ₁ include alkylene groups such as a methylene group, an ethylene group, a propylene group, and a butylene group.

In the above formula 2, R ₂ may be a direct bond or a straight or branched divalent organic group having 1 to 20 carbon atoms with or without a heteroatom, and * is a bond.

Examples of the linear or branched divalent organic group of _R2 containing or not containing a heteroatom having 1 to 20 carbon atoms include alkylene groups such as methylene, ethylene, propylene, and butylene groups, and aromatic hydrocarbon groups such as phenylene and biphenylene groups, in which at least one carbon atom is substituted or not substituted with a heteroatom. In this case, the alkylene group substituted with a heteroatom refers to a group having at least 2 carbon atoms.

The alkali-soluble resin (B) according to the present invention contains the structural unit represented by the chemical formula 1 and the structural unit represented by the chemical formula (2), which is advantageous in reducing residues and has the advantage of ensuring the reliability of light resistance, durability, and heat resistance.

The unit represented by Chemical Formula 1 may be derived from N-benzylmaleimide, but is not limited thereto.

The unit represented by the chemical formula 2 may be derived from cyclohexyl (meth)acrylate, but is not limited thereto.

The alkali-soluble resin (B) of the present invention includes a structure represented by the chemical formula 1 and a structure represented by the chemical formula (2), and may further include other copolymerizable comonomers, if necessary.

Such comonomers include unsaturated carboxyl group-containing monomers and other monomers that can be photopolymerized with them.

Examples of the unsaturated carboxyl group-containing monomer include unsaturated carboxylic acids having one or more carboxyl groups in the molecule, such as unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, and unsaturated tricarboxylic acids.

Examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-chloroacrylic acid, and cinnamic acid. Examples of the unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid.

The unsaturated polycarboxylic acid may be an acid anhydride, and specific examples thereof include maleic anhydride, itaconic anhydride, and citraconic anhydride. The unsaturated polycarboxylic acid may be a mono(2-methacryloyloxyalkyl)ester thereof, such as mono(2-acryloyloxyethyl) succinate, mono(2-methacryloyloxyethyl) succinate, mono(2-acryloyloxyethyl) phthalate, and mono(2-methacryloyloxyethyl) phthalate. The unsaturated polycarboxylic acid may be a mono(meth)acrylate of a polymer having dicarboxylates at both ends, such as ω-carboxypolycaprolactone monoacrylate and ω-carboxypolycaprolactone monomethacrylate.

The carboxyl group-containing monomers can be used alone or in combination of two or more.

Examples of other monomers copolymerizable with the carboxyl group-containing monomer include aromatic vinyl compounds such as styrene, α-methylstyrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, p-chlorostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-vinylbenzyl methyl ether, m-vinylbenzyl methyl ether, p-vinylbenzyl methyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and indene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, i-propyl acrylate, i-propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, 2-hydroxyethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, allyl acrylate, allyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, phenyl acrylate, phenyl methacrylate, 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, methoxydiethylene glycol acrylate, methoxydiethylene glycol methacrylate, methoxytriethylene glycol acrylate, methoxytriethylene glycol methacrylate, methoxypropylene glycol acrylate, methoxypropylene glycol methacrylate unsaturated carboxylic acid esters such as 2-aminoethyl acrylate, 2-aminoethyl methacrylate, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl methacrylate, 2-aminopropyl acrylate, 2-aminopropyl methacrylate, 2-dimethylaminopropyl acrylate, 2-dimethylaminopropyl methacrylate, 2-dimethylaminopropyl acrylate, 2-dimethylaminopropyl methacrylate, 3-aminopropyl acrylate, 3-aminopropyl methacrylate, 3-dimethylaminopropyl acrylate, 3-dimethylaminopropyl methacrylate, 3-dimethylaminopropyl acrylate, 3-dimethylaminopropyl methacrylate, and glycidyl acrylate; unsaturated carboxylic acid glycidyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, etc.; unsaturated ethers such as vinyl methyl ether, vinyl ethyl ether, allyl glycidyl ether, etc.; vinyl cyanide compounds such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, vinylidene cyanide, etc.; acrylamide, methacrylamide, α-chloroacrylamide, N-2-hydroxyethylacrylamide , unsaturated amides such as N-2-hydroxyethyl methacrylamide; unsaturated imides such as maleimide, N-phenylmaleimide, and N-cyclohexylmaleimide; aliphatic conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene; and macromonomers having a monoacryloyl group or monomethacryloyl group at the end of the polymer molecular chain, such as polystyrene, polymethyl acrylate, polymethyl methacrylate, poly-n-butyl acrylate, poly-n-butyl methacrylate, and polysiloxane. These monomers can be used alone or in combination of two or more.

The white photosensitive resin composition according to the present invention may further contain another alkali-soluble resin (B-2) in addition to the above-mentioned alkali-soluble resin (B).

There are no particular limitations on the other alkali-soluble resin (B-2) as long as it does not reduce the intended effect of the present invention when used in combination with the alkali-soluble resin (B).

For example, the other alkali-soluble resin (B-2) may be a copolymer containing one or more monomers selected from vinyl toluene, methoxystyrene, 8-tricyclodecanyl methacrylate, methyl methacrylate, etc., but is not limited thereto.

When the white photosensitive resin composition of the present invention is used together with the alkali-soluble resin (B) and another alkali-soluble resin (B-2), it has the advantage of being easy to form a pattern with the same line width even if the development process in which a pattern is formed using a developer changes. However, it is more preferable that the white photosensitive resin composition of the present invention contains only the alkali-soluble resin (B) alone, in order to provide not only small changes in line width during pattern formation, but also excellent effects in preventing the generation of residues, improving transmission strength, and improving heat resistance.

In the present invention, the alkali-soluble resin (B) may be contained in an amount of 20 to 70 parts by weight, preferably 25 to 65 parts by weight, and more preferably 30 to 60 parts by weight, per 100 parts by weight of the total solid content in the white photosensitive resin composition.

When the alkali-soluble resin (B) is contained within the above range, it has the advantages of sufficient solubility in the developer, easy formation of a cured film, prevention of film reduction in the pixel portion of the exposed area during development, and good chipping resistance in the non-pixel portion.

In addition, when the alkali-soluble resin (B) according to the present invention is contained, there is an advantage in that a pattern of the same line width can be easily formed even when the development process in which a pattern is formed using a developer is changed.

(C) Polymerizable Compound The polymerizable compound contained in the white photosensitive resin composition of the present invention is a compound that can be polymerized by light and heat, and any polymerizable compound known in this field can be selected and used without particular limitation as long as it can be polymerized by light and heat. Specific examples of the polymerizable compound include monofunctional monomers, bifunctional monomers, and other polyfunctional monomers.

The types of the monofunctional monomer, the bifunctional monomer, and the polyfunctional monomer are not particularly limited, and examples of the polyfunctional monomer that can be used include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

Commercially available examples of the double bond monomer include, but are not limited to, Miramer M600 from Miwon Commercial.

The polymerizable compound may be contained in an amount of 5 to 50 parts by weight, preferably 10 to 40 parts by weight, per 100 parts by weight of the total solid content of the white photosensitive resin composition. When contained within the above range, favorable benefits are obtained in terms of the strength and smoothness of the pixel portion.

If the double bond monomer is contained below the range, the strength of the coating film may be somewhat reduced, and if the double bond monomer is contained above the range, the smoothness may be somewhat reduced, so it is preferable that the double bond monomer is contained within the range.

(D) Photopolymerization Initiator The white photosensitive resin composition according to the present invention may contain a photopolymerization initiator.

The photopolymerization initiator may be a photopolymerization initiator generally used in photosensitive resin compositions, or a photopolymerization initiator known in this field may be selected and used without any particular restrictions. For example, acetophenone-based, benzophenone-based, triazine-based, thioxanthone-based, oxime-based, benzoin-based, non-imidazole-based compounds, etc. may be used.

For example, oxime compounds such as o-ethoxycarbonyl-α-oxyamino-1-phenylpropan-1-one may be used, and representative commercially available products include OXE-01 and OXE-02 from Ciba.

The photopolymerization initiators may be used alone or in combination of two or more.
The photopolymerization initiator can be used in an amount of 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the total solid content of the white photosensitive resin composition. The range of content is determined by considering the photopolymerization rate of the polymerizable compound and the physical properties of the coating film finally obtained. If the content is less than the range, the polymerization rate is low and the overall process time is long, and conversely, if the content exceeds the range, the crosslinking reaction due to an excessive reaction may occur, resulting in a deterioration in the physical properties of the coating film. Therefore, it is preferable to use the photopolymerization initiator appropriately within the range.

In addition, a photopolymerization initiator assistant can be used together with the photopolymerization initiator. When a photopolymerization initiator assistant is used together with the photopolymerization initiator, the white photosensitive resin composition becomes even more sensitive, and the productivity is improved, which is preferable.

As the photopolymerization initiator, one or more compounds selected from the group consisting of amines and carboxylic acid compounds can be preferably used.

Such photopolymerization initiator aids are usually used in an amount of 10 moles or less, preferably in the range of 0.01 to 5 moles, per mole of photopolymerization initiator. When the photopolymerization initiator aid is used within the above range, it is expected that the polymerization efficiency will be increased and the productivity will be improved.

(E) Solvent The solvent contained in the white photosensitive resin composition of the present invention is not particularly limited, and various organic solvents known in the field of photosensitive resin compositions can be used.

In terms of coatability and drying property, the solvent may be an organic solvent having a boiling point of 100°C to 200°C, more preferably alkylene glycol alkyl ether acetates, ketones, esters such as ethyl 3-ethoxypropionate and methyl 3-methoxypropionate, more preferably propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, etc. The solvents may be used alone or in combination of two or more kinds.

The content of the solvent may be typically 60 to 90 parts by weight, preferably 70 to 85 parts by weight, per 100 parts by weight of the total white photosensitive resin composition containing the solvent. When the content of the solvent satisfies the above range, the coating properties tend to be good when applied with a coating device such as a roll coater, spin coater, slit and spin coater, slit coater (sometimes called a die coater), or inkjet, which is preferable.

Additives The white photosensitive resin composition according to one embodiment of the present invention may further contain additives, if necessary.

The type of additive is determined according to the needs of the user, and is not particularly limited in the present invention. Examples of the additive include other polymer compounds, heat curing agents, surfactants, adhesion promoters, antioxidants, anti-aggregation agents, dispersants, etc. The additives exemplified above can be used alone or in combination of two or more kinds.

Specific examples of the other polymer compounds include curable resins such as epoxy resins and maleimide resins, and thermoplastic resins such as polyvinyl alcohol, polyacrylic acid, polyethylene glycol monoalkyl ether, polyfluoroalkyl acrylate, polyester, and polyurethane.

The antioxidant may include, for example, one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and phenol-based antioxidants. In this case, discoloration that may occur at high temperatures during the process or yellowing that may be induced by a light source after the display is manufactured can be suppressed. The antioxidant may include one or more selected from the group consisting of phenolic compounds, phosphorus-based compounds, and sulfur-based compounds, and these can be used in combination as phenolic-phosphorus compounds, phenolic-sulfur compounds, phosphorus-sulfur compounds, or phenolic-phosphorus-sulfur compounds.

The antioxidant may be included in an amount of 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the total solid content of the white photosensitive resin composition of the present invention. When the content of the antioxidant satisfies the above range, it is advantageous in terms of solving the problem of reduced luminescence intensity.

The dispersant is added to maintain the dispersion stability of the pigment, and any dispersant commonly used in the field can be used without restriction.

The method for producing the white photosensitive resin composition of the present invention can be a method that is generally known in the art, and is not particularly limited in the present invention. One example of the method for producing the composition is as follows.

The scattering particles are mixed with a solvent in advance and dispersed using a bead mill or the like until the average particle size is 30 to 300 nm. At this time, if necessary, a dispersant may be further used, or part or all of the alkali-soluble resin may be blended. The remaining alkali-soluble resin, polymerizable compound, photopolymerization initiator, other components used as necessary, and additional solvent as necessary may be further added to the obtained dispersion (hereinafter sometimes referred to as mill base) to a predetermined concentration to obtain the desired white photosensitive resin composition.

In addition, after preparing a preliminary composition by mixing the above components except for the scattering particles, a white photosensitive resin composition can be prepared by adding the scattering particles to the preliminary composition.

<Scattered pixels>
The present invention provides a scattering pixel fabricated using the above-mentioned white photosensitive resin composition.

The scattering pixel is a coating film formed by applying the above-mentioned white photosensitive resin composition on a substrate, exposing and developing it in a predetermined pattern. The white photosensitive resin composition of the present invention used to form the coating film does not contain quantum dots, and preferably does not substantially contain other colorants other than the above-mentioned scattering particles in order to improve the transmission efficiency of blue light. However, the white photosensitive resin composition for manufacturing the scattering pixel of the present invention may contain a small amount of colorant depending on the characteristics required for the scattering pixel.

The scattering pixel of the present invention is particularly suitable for use in image display devices, and may refer to a blue pixel layer that transmits blue light emitted by a blue light source and thus displays a blue color.

The scattering pixel of the present invention is more suitable for use in quantum dot displays that use a blue light source. For example, in the red and green pixel layers, the quantum dots located in each pixel are converted to red and green by blue light, respectively, and the image is realized by the scattered light, while the blue pixel layer uses the blue light source as is. In this case, the blue light source transmits direct light, making it difficult to realize the desired color, and scattered light is also required for blue, so the white photosensitive resin composition of the present invention is used to impart a scattering effect to the blue pixel layer.

The scattering pixel of the present invention is manufactured using the white photosensitive resin composition described above, which has the advantages of lowering manufacturing costs, improving transmitted light intensity, and providing an excellent viewing angle.

<Color filter>
The present invention provides a color filter that includes the scattering pixels described above.

When the color filter of the present invention is applied to an image display device, it emits light using the light source of the display device, and therefore can achieve better light efficiency. In addition, since light having a hue is emitted, it has better color reproducibility, and since light is emitted in all directions by photoluminescence, it has an improved viewing angle and excellent brightness characteristics.

Referring to FIG. 2, the color filter according to the present invention includes a substrate and a pixel layer formed on one surface of the substrate. The pixel layer may be formed to include scattering pixels and red and green pattern layers.

In the present invention, by using a light source that emits blue light, the red pattern layer or the green pattern layer can emit red light or green light, respectively, by the light source that emits blue light, and the scattering pixels can show blue color without color conversion because the blue light is transmitted as it is, unlike the conventional scattering pixels that use a white light source.

The substrate may be the substrate of the color filter itself or a portion of a display device where the color filter is located, and is not particularly limited. The substrate may be glass, silicon (Si), silicon oxide (SiOx), or a polymer substrate, and the polymer substrate may be polyethersulfone (PES) or polycarbonate (PC), etc.

In the present invention, the scattering pixels may not contain quantum dots, and the red and green pattern layers may contain quantum dots.

The pattern layer may be a coating film formed by applying a colored photosensitive resin composition known in the technical field of the present invention, exposing it to light in a predetermined pattern, developing it, and thermally curing it, or the pattern layer may be formed by a method commonly known in the art.

A light source that emits blue light can be used as the light source of an image display device including the color filter according to the present invention. In this case, the red pattern layer emits red light, the green pattern layer emits green light, and the scattering pixels transmit the blue light as it is, thereby showing the blue color.

<Image display device>
The present invention provides an image display device including the scattering layer according to the present invention.

Examples of the image display device include liquid crystal displays (liquid crystal display devices; LCDs), organic electroluminescence displays (organic electroluminescence display devices), quantum dot displays, liquid crystal projectors, display devices for game consoles, display devices for mobile terminals such as mobile phones, display devices for digital cameras, and display devices for car navigation systems, and the image display device according to one embodiment of the present invention may be a quantum dot display.

The image display device may include other components that are typically included in an image display device, such as a light-emitting device such as a light source, a light guide plate, and a liquid crystal display unit including a color filter, but the present invention is not limited to these.

In the present invention, the light emitted by the light source applied to the image display device is not particularly limited, but in terms of better color reproducibility, a light source that emits blue light can be preferably used.

The present invention will be described in more detail below based on examples, but the embodiments of the present invention disclosed below are merely illustrative and the scope of the present invention is not limited to these embodiments. The scope of the present invention is set forth in the claims, and further includes all modifications that have the same meaning and scope as those recorded in the claims. In the following examples and comparative examples, the "%" and "parts" indicating the content are by weight unless otherwise specified.

<Synthesis Example>
Synthesis Example 1: Synthesis of alkali-soluble resin (B-1)
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen inlet tube was prepared. On the one hand, 15 parts by weight of N-benzylmaleimide, 30 parts by weight of acrylic acid, 50 parts by weight of cyclohexyl methacrylate, 5 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were charged and then stirred and mixed to prepare a dropping funnel for the monomer, and 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were charged and stirred and mixed to prepare a dropping funnel for the chain transfer agent.

After that, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Next, the dropping of the monomer and chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining the temperature at 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 3 hours, after which a gas inlet tube was introduced and bubbling of a mixed gas of oxygen/nitrogen = 5/95 (v/v) was started.

Next, 20 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were added to the flask, and the reaction was continued at 110°C for 6 hours. After that, the mixture was cooled to room temperature to obtain an alkali-soluble resin (B-1) with a weight average molecular weight of 3,800 and a solids-based acid value of 83 mgKOH/g.

Synthesis Example 2
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was prepared. On the one hand, 5 parts by weight of N-benzylmaleimide, 50 parts by weight of acrylic acid, 40 parts by weight of cyclohexyl methacrylate, 5 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were charged and then stirred and mixed to prepare a dropping funnel for the monomer. 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were charged and stirred and mixed to prepare a dropping funnel for the chain transfer agent.

After that, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Next, the dropping of the monomer and chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining the temperature at 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 3 hours, after which a gas inlet tube was introduced and bubbling of a mixed gas of oxygen/nitrogen = 5/95 (v/v) was started.

Next, 30 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were added to the flask, and the reaction was continued at 110°C for 8 hours. After that, the mixture was cooled to room temperature to obtain an alkali-soluble resin (B-2) with a solid content of 29.1% by weight, a weight average molecular weight of 6,700, and a solid content standard acid value of 130 mgKOH/g.

Synthesis Example 3
20 parts by weight of vinyl toluene, 5 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were added, and then stirred and mixed to prepare a dropping funnel for the monomer. 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were added, and then stirred and mixed to prepare a dropping funnel for the chain transfer agent.

After that, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Next, the dropping of the monomer and chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining the temperature at 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 3 hours, after which a gas inlet tube was introduced and bubbling of a mixed gas of oxygen/nitrogen = 5/95 (v/v) was started.

Next, 50 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were added to the flask, and the reaction was continued at 110°C for 8 hours. After that, the mixture was cooled to room temperature to obtain an alkali-soluble resin (B-3) with a solid content of 33.2% by weight, a weight average molecular weight of 8,000, and a solid content standard acid value of 135 mgKOH/g.

Synthesis Example 4
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was prepared. On the one hand, 10 parts by weight of 8-tricyclodecanyl methacrylate, 40 parts by weight of acrylic acid, 40 parts by weight of cyclohexyl methacrylate, 10 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were charged and then stirred and mixed to prepare a dropping funnel for the monomer, and 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were charged and stirred and mixed to prepare a dropping funnel for the chain transfer agent.

After that, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Next, the dropping of the monomer and chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining the temperature at 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 3 hours, after which a gas inlet tube was introduced and bubbling of a mixed gas of oxygen/nitrogen = 5/95 (v/v) was started.

Next, 30 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were added to the flask, and the reaction was continued at 110°C for 8 hours. After that, the mixture was cooled to room temperature to obtain an alkali-soluble resin (B-4) with a solid content of 30.1% by weight, a weight average molecular weight of 6,900, and a solid content standard acid value of 90 mgKOH/g.

Synthesis Example 5
A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube was prepared. On the one hand, 10 parts by weight of 8-tricyclodecanyl methacrylate, 40 parts by weight of acrylic acid, 30 parts by weight of vinyl toluene, 20 parts by weight of methyl methacrylate, 4 parts by weight of t-butylperoxy-2-ethylhexanoate and 40 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as PGMEA) were charged and then stirred and mixed to prepare a dropping funnel for the monomer. 6 parts by weight of n-dodecanediol and 24 parts by weight of PGMEA were charged and stirred and mixed to prepare a dropping funnel for the chain transfer agent.

After that, 395 parts by weight of PGMEA was introduced into the flask, the atmosphere in the flask was replaced from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Next, the dropping of the monomer and chain transfer agent was started from the dropping funnel. The dropping was carried out for 2 hours each while maintaining the temperature at 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 3 hours, after which a gas inlet tube was introduced and bubbling of a mixed gas of oxygen/nitrogen = 5/95 (v/v) was started.

Next, 30 parts by weight of glycidyl methacrylate, 0.4 parts by weight of 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 0.8 parts by weight of triethylamine were added to the flask, and the reaction was continued at 110°C for 8 hours. After that, the mixture was cooled to room temperature to obtain an alkali-soluble resin (B-5) with a solid content of 29.8% by weight, a weight average molecular weight of 6,200, and a solid content standard acid value of 90 mgKOH/g.

Preparation Examples 1 to 5: Preparation of preliminary compositions Preliminary compositions containing an alkali-soluble resin, a polymerizable compound, a photopolymerization initiator, a dispersant, an antioxidant, and an epoxy resin were prepared in Preparation Examples 1 to 5 according to Table 1 below.

-Alkali-soluble resins B-1 to B-5: Synthesis examples 1 to 5
Polymerizable compound: dipentaerythritol hexaacrylate (Kayarad DPHA, manufactured by Nippon Kagaku Co., Ltd.)
Photopolymerization initiator: Irgacure OXE01 (manufactured by Basf)
Dispersant: DISPERBYK-110 (manufactured by BYK)
- Antioxidant: Sumilizer GP (Sumitomo Chemical)
-Epoxy resin: ESCN 195XL (manufactured by Sumitomo Chemical)
- Solvent: Propylene glycol monomethyl ether acetate (PGMEA)
Examples 1 to 6 and Comparative Examples 1 to 3: Preparation of White Photosensitive Resin Compositions
According to Table 2, the scattering particles and the preliminary compositions of Preparation Examples 1 to 5 were mixed to prepare the white photosensitive resin compositions of Examples 1 to 6 and Comparative Examples 1 to 3.

<Fabrication of Scattering Pixels>
A scattering pixel was manufactured using the white photosensitive resin composition manufactured according to the examples and comparative examples. That is, each of the white photosensitive resin compositions was applied onto a glass substrate by spin coating, and then placed on a heating plate and maintained at 100° C. for 3 minutes to remove the solvent, thereby forming a coating film.

Next, a test photomask with a square transmission pattern of 20 mm x 20 mm and a line pattern of 1 to 100 μm was placed on the coating film, and ultraviolet light was irradiated with a distance of 100 μm from the test photomask.

At this time, the ultraviolet light source was an ultra-high pressure mercury lamp (product name: USH-250D) manufactured by Ushio Inc., and light was irradiated at an exposure dose of 200 mJ/ ^cm2 (based on 365 nm) in an air atmosphere, and no special optical filter was used.

The coating film irradiated with UV rays was developed by immersing it in a pH 10.5 KOH aqueous solution development solution for a predetermined time (80 seconds and 160 seconds, respectively). The glass substrate on which the coating film was formed was washed with distilled water, dried by blowing in nitrogen gas, and heated in a heating oven at 230°C for 20 minutes to produce a hardened film of a scattering pixel pattern. The thickness of the scattering pixel film produced above was 10 μm.

<Experimental Example>
Experimental Example 1: Measurement of Residue
Among the scattering pixels prepared using the white photosensitive resin compositions prepared according to the examples and comparative examples, the line patterned portions were measured using an optical microscope (Eclipse LV100POL, Nikon Corporation). Based on FIG. 1, the residue level was expressed as ◯ (no residue) or × (residue) depending on the presence or absence of the resin composition residue in the non-exposed portion. The criteria for the residue measurement are shown in FIG. 1, and the results are shown in Table 3.

Experimental Example 2: Measurement of transmission intensity A region where light was converted into light was measured using a 365 nm tube-type 4W UV irradiator (VL-4LC, VILBER LOURMAT) in a 20×20 mm square pattern of the scattering pixels prepared using the white photosensitive resin compositions prepared according to Examples 1 to 6 and Comparative Examples 1 to 3, and the emission intensity (i.e., transmission intensity) in the 450 nm region was measured using a Spectrum meter (Ocean Optics). The measurement results are shown in Table 3. At this time, the higher the measured transmission intensity value, the better the blue light transmission efficiency.

Experimental Example 3: Evaluation of heat resistance The scattering pixels prepared using the white photosensitive resin compositions prepared according to Examples 1 to 6 and Comparative Examples 1 to 3 were heated in a heating oven at 230° C. for 2 hours, and the color change before and after heating was measured and calculated according to Equation (1), and the results are shown in Table 3. The larger the value calculated according to Equation (1), the larger the color change before and after heating, meaning that the pixel is unsuitable for use.

Mathematical formula (1) ΔEab*=[(ΔL*) ² + (Δa*) ² + (Δb*) ² ] ^1/2
Experimental Example 4: Measurement of line width change
In the manufacture of the scattering pixels, the line width of a 100 μm line mask pattern was measured using an optical microscope (Eclipse LV100POL, Nikon Corporation) for a substrate that had been developed for 80 seconds and a substrate that had been developed for 160 seconds. The change in the pattern line width of the substrate after 80 seconds and the pattern line width of the substrate after 160 seconds were measured, and the results are shown in Table 3 below.

Referring to Table 3, it was confirmed that the scattering pixels manufactured with the white photosensitive resin compositions of Examples 1 to 6 had no residues overall and exhibited excellent heat resistance. It was also confirmed that they exhibited excellent effects in terms of line width change.

On the other hand, it was confirmed that the scattering pixels manufactured with the white photosensitive resin compositions of Comparative Examples 1 to 3 had a relatively significant decrease in the effects of residue prevention, transmission intensity, and/or heat resistance compared to Examples 1 to 6 of the present application. In addition, it was confirmed that the change in line width was at least twice as large as that of the embodiment of the present invention.

More specifically, the results of the experiment in Experimental Example 1 show that the cured film of the scattering pixel manufactured using the white photosensitive resin composition of Examples 1 to 6 has no residue of the resin composition in the unexposed area after pattern formation, and does not change color even in an additional heat process, and has heat resistance. Therefore, it can be seen that in a display device using a blue light source as a light source using the white photosensitive resin composition of the present invention, the scattering pixel of the present invention can exhibit uniform performance without distorting the light source.

On the other hand, it was confirmed that the cured film of the scattering pixels manufactured using the white photosensitive resin compositions of Comparative Examples 1 to 3 had residual resin composition in the unexposed areas after pattern formation, and the color change due to the additional heat process was large, distorting the light source and causing severe performance degradation due to the additional process.

Claims (2)

A color filter comprising scattering pixels manufactured using a white photosensitive resin composition,
The white photosensitive resin composition comprises: (A) scattering particles; (B) an alkali-soluble resin; (C) a polymerizable compound; (D) a photopolymerization initiator; and (E) a solvent;
The alkali-soluble resin (B) contains a unit represented by the following Chemical Formula 1 and a unit represented by the following Chemical Formula 2:
The scattering pixel is a scattering pixel that exhibits blue color when exposed to a blue light source. A color filter (excluding those containing a colorant (F)).

(In the above Chemical Formula 1,
R ₁ is a direct bond or a linear or branched divalent organic group having 1 to 6 carbon atoms;
* is a bond.)

(In the above Chemical Formula 2,
_R2 is a directly bonded, linear or branched divalent organic group having 1 to 20 carbon atoms and containing or not containing a heteroatom;
* is a bond.) An image display device comprising the color filter according to claim 1.

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