JP2013080044A - Color filter for white light emitting diode light source and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter capable of reducing the color shift of a display image even when used in combination with a white LED light source, and a display device including the color filter and a white LED light source.SOLUTION: There is provided a color filter for a white light emitting diode light source having at least a red pixel, a green pixel and a blue pixel, wherein the color filter has an average transmittance of 80% or more at a wavelength of 420 to 460 nm of the blue pixel and is used for a white light emitting diode light source having a maximum value of a light-emitting spectrum in the wavelength of 430 to 450 nm and variations (σ) in the maximum value wavelengths of 3 or more. There is provided a display device comprising a white light emitting diode light source having a maximum value of a light-emitting spectrum in the wavelength of 430 to 450 nm and variations (σ) in the maximum value wavelengths of 3 or more and the color filter for a white light emitting diode light source.

Description

  The present invention relates to a color filter used in a liquid crystal display device or an organic EL display device, and a display device including the color filter.

Conventionally, in a liquid crystal display device, a CCFL (cold cathode fluorescent lamp) light source has been used as a light source of a backlight.
In recent years, white light emitting diode light sources (hereinafter sometimes simply referred to as “LED light sources”) have been adopted in liquid crystal display devices in place of CCFL light sources from the viewpoints of low power consumption and expansion of color reproduction regions. (For example, Patent Document 1).

JP 2010-128310 A

As a result of intensive studies by the present inventors, it has been found that the emission spectrum of a blue LED element (blue light-emitting diode element) used in an LED light source varies about 10 nm in production. Further, it was found that the wavelength region of the transmission spectrum is narrow in the conventional LED color filter.
For this reason, in the combination of the LED light source and the conventional LED color filter, the variation in the emission spectrum of the LED light source causes a shift in the wavelength region of the emission spectrum and the transmission spectrum wavelength region of the color filter. It was found that the shift appears as a color shift.
In particular, it has been found that there is a significant individual difference in the color that is reproduced in the case of a display device having a small number of blue LED elements constituting the LED light source such as a mobile terminal.

  The present invention has been made to solve the above problems, and provides a color filter that can reduce color misregistration even when combined with an LED light source, and a display device including the color filter and the LED light source. For the purpose.

  As a result of intensive studies by the present inventors, it has been found that by using a color filter having a blue pixel having a wide wavelength range of the transmission spectrum, even if the emission spectrum of the LED light source varies, color shift can be reduced, and the present invention has been completed. I came to let you.

  That is, the color filter according to the present invention is a white light-emitting diode light source color filter having at least a red pixel, a green pixel, and a blue pixel, and an average transmittance of the blue pixel at a wavelength of 420 to 460 nm is 80% or more, In addition, it is used for a white light emitting diode light source whose emission spectrum has a maximum value at a wavelength of 430 to 450 nm and whose variation (σ) of the maximum value wavelength is 3 or more.

An emission spectrum of a blue LED element (blue light emitting diode element) included as a base LED element in a white LED light source is preferably one having a maximum value in a range of 430 to 450 nm, but for a blue LED element constituting a white LED light source, There are individual differences, and there are many individuals whose wavelength deviation from the standard value is about 10 nm, and the white LED light source as a whole has a maximum value at a wavelength of 430 to 450 nm and constitutes the light source. In many cases, the variation (σ) of the maximum wavelength as a whole of the white LED light source from the standard value of the maximum wavelength is 3 or more.
According to the present invention, the wavelength range in which the transmittance of the blue pixel of the color filter is 80% or more is made wider than the wavelength range in which the maximum wavelength of the white LED light source exists, thereby suppressing the color shift of the display image seen through the color filter. Reduce. That is, according to the present invention, assuming the variation of the emission spectrum of the blue LED element, which is the base LED element included in the white LED light source, by overlapping the emission spectrum of the white LED element and the transmission spectrum of the blue pixel, Reduce color shift in the displayed image.

  In the color filter for LED light source according to the present invention, the difference between the maximum value and the minimum value of the transmittance of the blue pixel at a wavelength of 420 to 460 nm is preferably 10% or less.

  The display device according to the present invention has a maximum value of an emission spectrum at a wavelength of 430 to 450 nm, and has a maximum wavelength variation (σ) of 3 or more, and the white light-emitting diode light source of the present invention described above. And a color filter.

  In the display device according to the present invention, even when the number of light emitting diode elements included in the white light emitting diode light source is 4 to 100, color misregistration hardly occurs and the display quality is excellent.

The color filter for an LED light source according to the present invention is an LED light source in which the variation (σ) of the maximum wavelength from the standard value of the maximum wavelength of the white LED element constituting the light source is 3 or more as a whole. Even in combination, color misregistration can be reduced, so that it is not necessary to select LED light sources, and an inexpensive liquid crystal display device can be provided.
Since the display device according to the present invention includes the color filter, it can be provided at low cost even when combined with an LED light source.

FIG. 1 is a cross-sectional view schematically showing an example of a color filter for an LED light source according to the present invention. FIG. 2 is a cross-sectional view schematically showing another example of the color filter for LED light source according to the present invention. FIG. 3 is a cross-sectional view schematically showing an example of the liquid crystal display device of the present invention. FIG. 4 is a cross-sectional view schematically showing an example of the organic EL display device of the present invention.

In the present invention, chromaticity is a value in CIE chromaticity coordinates.
In the present invention, (meth) acrylate represents acrylate and / or methacrylate.
In the present invention, the resin is a concept including a polymer in addition to a monomer and an oligomer.
In the present invention, the molecular weight means a weight average molecular weight which is a polystyrene equivalent value measured by gel permeation chromatography (GPC) in a THF solvent when having a molecular weight distribution, and when having no molecular weight distribution, It means the molecular weight of the compound itself.

  Hereinafter, the color filter for white light emitting diode light source according to the present invention will be described first, and then the display device will be described.

(Color filter for white light-emitting diode light source)
The color filter according to the present invention is a white light-emitting diode light source color filter having at least a red pixel, a green pixel, and a blue pixel, and an average transmittance at a wavelength of 420 to 460 nm of the blue pixel is 80% or more, and It is used for a white light emitting diode light source having an emission spectrum having a maximum value at a wavelength of 430 to 450 nm and a variation (σ) of the maximum value wavelength being 3 or more.

An emission spectrum of a blue LED element (blue light emitting diode element) included as a base LED element in a white LED light source is preferably one having a maximum value in a range of 430 to 450 nm, but for a blue LED element constituting a white LED light source, There are individual differences, and there are many individuals whose wavelength deviation from the standard value is about 10 nm, and the white LED light source as a whole has a maximum value at a wavelength of 430 to 450 nm and constitutes the light source. In many cases, the variation (σ) of the maximum wavelength as a whole of the white LED light source from the standard value of the maximum wavelength is 3 or more.
According to the present invention, the wavelength range in which the transmittance of the blue pixel of the color filter is 80% or more is made wider than the wavelength range in which the maximum wavelength of the white LED light source exists, thereby suppressing the color shift of the display image seen through the color filter. Reduce. That is, according to the present invention, assuming the variation of the emission spectrum of the blue LED element, which is the base LED element included in the white LED light source, by overlapping the emission spectrum of the white LED element and the transmission spectrum of the blue pixel, Reduce color shift in the displayed image.

FIG. 1 is a cross-sectional view schematically showing an example of a color filter for an LED light source according to the present invention.
As shown in FIG. 1, the color filter usually includes a transparent substrate 10, a red pixel 21, a green pixel 22, a blue pixel 23, and a light shielding unit 30 that are colored pixels formed on the transparent substrate 10.
The color filter for an LED light source according to the present invention includes, for example, a protective film, a transparent electrode film, an alignment film, and a columnar spacer other than the transparent substrate 10, the colored pixels 21 to 23, and the light shielding portion 30. May be.
In FIG. 1 and the subsequent drawings, for convenience of explanation, the vertical and horizontal dimension ratios and the dimension ratios between the layers and the members are exaggerated as appropriate instead of the actual dimensions.

(Transparent substrate)
The transparent substrate 10 in the color filter for an LED light source of the present invention is not particularly limited as long as it is a substrate transparent to visible light, and a transparent substrate used for a general color filter can be used. . Examples thereof include a transparent substrate having no flexibility such as quartz glass, alkali-free glass, and synthetic quartz plate, and a transparent substrate having flexibility such as a transparent resin film and an optical resin plate.
Although the thickness of the transparent substrate 10 is not specifically limited, For example, the thing of about 100 micrometers-1 mm can be used according to the use of the color filter of this invention.

(Colored pixels)
The colored pixels in the color filter for the LED light source of the present invention may include the blue pixels 21, the green pixels 22, and the red pixels 23, as long as the blue pixels 21 have a certain transmittance at a predetermined wavelength as described above. . Therefore, the green pixel 22 and the red pixel 23 can be conventionally known pixels. Further, pixels other than the colored pixels of the three colors may be included.
Normally, the colored pixels are formed by curing the color filter resin composition of each color in the opening between the light shielding portions 30 formed on the transparent substrate 10 as shown in FIG.
Further, the arrangement of the colored pixels is not particularly limited, and for example, a general arrangement such as a stripe type, a mosaic type, a triangle type, or a four pixel arrangement type can be used. Moreover, the width | variety, area, etc. of a coloring pixel can be set arbitrarily.
The thickness of the colored pixel is appropriately controlled by adjusting the coating method, the solid content concentration, the viscosity, and the like of the color filter resin composition, but is usually preferably in the range of 1 to 5 μm.

(Blue pixel)
In the color filter for LED light source according to the present invention, it is preferable that the chromaticity coordinates of the blue pixel measured using the C light source are x = 0.135 to 0.148 and y = 0.070 to 0.150.
In the color filter for LED light source of the present invention, the average transmittance of blue pixels at a wavelength of 430 to 460 nm is 80% or more.
A white LED constituting a light source, in which the emission spectrum of a blue LED element included as a base LED element in a white LED light source is shifted by about 10 nm from the standard value, and the white LED light source as a whole has a maximum value at a wavelength of 430 to 450 nm. Even when the variation (σ) of the maximum wavelength of the entire white LED light source from the standard value of the maximum wavelength of the element (the wavelength at which the maximum value exists) is 3 or more, it corresponds to the maximum wavelength. By expanding the wavelength range of the blue pixel of the color filter to 420 to 460 nm and setting the transmittance in the wavelength range to 80% or more, the color shift of the display image is reduced.
In the present invention, the transmittance refers to a coating film having a thickness of 2 to 3 μm produced by uniformly dispersing a colorant at a concentration of 30% by mass using a microspectroscope OSP-SP2000 manufactured by OLYMPUS Co., Ltd. It means the transmittance in the transmission spectrum when measured.

  In the color filter for an LED light source according to the present invention, it is preferable that the difference between the maximum value and the minimum value of the blue pixel at a wavelength of 430 to 460 nm is 10% or less. As a result, even if the emission spectrum of the LED light source is greatly shifted to the wavelength 430 nm side or the wavelength 460 nm side from the standard value, the deviation between the emission spectrum of the LED light source and the transmission spectrum of the blue pixel is small. Further, the color shift of the display image is difficult to occur.

The blue pixel of the color filter for LED light source of the present invention may have any specific transmittance as described above, and color materials such as pigments and dyes used in conventionally known blue pixels can be used. .
In order to set the transmittance of the blue pixel at a wavelength of 430 to 460 nm to 80% or more, and more preferably to set the difference between the maximum value and the minimum value of the transmittance of the blue pixel at a wavelength of 430 to 460 nm to 10% or less, for example, The reel methane color material may be used in a content ratio of 30 to 100% by mass, more preferably 40 to 100% by mass with respect to the entire color material.
Specific examples of the triarylmethane dye include the following.

(In the formula, each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom, and R ₂ , R ₃ , R ₄ , and R ₅ are each independently A hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, an optionally substituted phenyl group, or an optionally substituted benzyl group)

(In the formula, each R ₁ independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom, and R ₂ , R ₃ , R ₄ , and R ₅ are each independently A hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, an optionally substituted phenyl group, or an optionally substituted benzyl group)

More specifically, as the triarylmethane dye, Basic Blue 7 can be mentioned.
In addition, a lake pigment having an ion of the chemical structural formula shown in the formula (2) can be used as the formula (1). Specific examples of the triarylmethane pigment used in the present invention include C.I. I. Pigment blue 1, C.I. I. Pigment blue 1: 2, C.I. I. Pigment blue 9, C.I. I. Pigment blue 14, C.I. I. Pigment blue 24, C.I. I. Pigment violet 3, C.I. I. Pigment violet 3: 1, C.I. I. Pigment violet 3: 3, C.I. I. Pigment violet 27, C.I. I. Pigment violet 39, C.I. I. Pigment blue 78, C.I. I. Pigment green 1, C.I. I. Pigment green 2, C.I. I. Pigment green 4, C.I. I. Pigment blue 56, C.I. I. Pigment blue 56: 1, C.I. I. Pigment blue 61, C.I. I. Pigment blue 61: 1, C.I. I. And lake pigments such as CI Pigment Blue 62.

(Green pixel and Red pixel)
The color filter for an LED light source according to the present invention includes a green pixel and a red pixel in addition to the blue pixel.
The green pixel and the red pixel can be respectively a green pixel and a red pixel provided in a conventionally known color filter.
In the color filter for LED light source according to the present invention, the chromaticity coordinates of the green pixel measured using the C light source are x = 0.25 to 0.30, y = 0.50 to 0.60, and red. The chromaticity coordinates of the pixels are preferably x = 0.60 to 0.70 and y = 0.30 to 0.35.

  Hereinafter, the resin composition for a color filter that cures to form the blue pixel will be described.

(Resin composition for color filter)
The resin composition for a color filter used in the present invention is a conventionally known color filter resin composition, and the color material depends on the type of each color pixel of blue pixel, green pixel and red pixel, transmittance, color, etc. May be used as appropriate. That is, the color material, the pigment dispersant, the binder, the photoinitiator, the catalyst, the solvent, and other components may be those of a conventionally known color filter resin composition.
The resin composition for a color filter is generally composed of a dispersion containing a colorant, a dispersant, a binder and a solvent, and a clear material containing a photoinitiator, a curing agent, a catalyst, a binder, a solvent and the like. Hereinafter, each of these components will be described without distinguishing between the dispersion and the clear material.

(Color material)
In the present invention, the color material is a concept including a pigment and a dye.
In the resin composition for a color filter for forming a blue pixel, a color material may be appropriately selected and used so that the blue pixel has an average transmittance of 80% or more at a wavelength of 430 to 460 nm. Since the preferable conditions have been described above, description thereof is omitted here.

The red pixel can include, for example, a conventionally known red pigment such as PR177, PR242, PR254, or PR208. In addition to the red pigment, the red pixel may contain conventionally known yellow pigments such as PY139 and PY150 in order to adjust contrast and color.
The green pixel may include, for example, a conventionally known green pigment such as PG1, PG4, PG7, PG36, or PG58. In addition to the green pigment, the green pixel may contain a conventionally known yellow pigment such as PY138 or PY150 in order to adjust contrast and color.

(Pigment particle size)
The average primary particle size of the pigment used in the present invention is not particularly limited as long as it can produce a desired color when used as a colored pixel of a color filter. The average primary particle diameter of the pigment varies depending on the type of pigment used, but is preferably in the range of 10 to 50 nm, and more preferably in the range of 10 to 40 nm from the viewpoint of improving contrast. When the average primary particle size of the pigment is in the above range, the liquid crystal display device and the organic EL display device produced using the resin composition for a color filter of the present invention can be easily made to have high contrast and high quality.
In addition, the average particle diameter of the pigment in the color filter can be obtained by a method of directly measuring the size of primary particles from an electron micrograph. Specifically, the minor axis diameter and major axis diameter of each primary particle are measured, and the average is taken as the particle diameter of the particle. Next, for 100 particles, the volume (weight) of each particle is obtained by approximating the obtained particle size to a rectangular parallelepiped, and the volume average particle size is obtained and used as the average particle size. The same result can be obtained regardless of whether the electron microscope is a transmission type (TEM) or a scanning type (SEM).
The particle size of the pigment in the dispersion can be measured using a Nitraso Co., Ltd. Nanotrac particle size analyzer UPA-EX.

  In the resin composition for a color filter, the mass ratio (P / V) between the color material (P) and the solid content (V) other than the color material is a required optical characteristic such as contrast, brightness, and color. It is preferable that it is 0.1-0.3 from a viewpoint of platemaking property.

(Dispersant)
In the color filter resin composition, a conventionally known dispersant can be used to disperse the pigment as necessary.
As such a dispersant, for example, a cationic, anionic, nonionic, amphoteric, silicone-based or fluorine-based surfactant described in Patent Document 1 can be used.
Further, for example, a polymer dispersant described in JP-A-2007-070342 is also preferably used.

  Examples of commercially available dispersants include trade name Polyflow No. manufactured by Kyoeisha Chemical Co., Ltd. 75, 90, 95, DIC Corporation's trade names MegaFuck F171, F172, F173, Big Chemie Japan Corporation DISPERBYK (registered trademark) 111, 130, 161, 162, 163, 164, 170, 182, 2000, 2001, trade names of Efka Co., Ltd., Efka 46, Efka 47, Zeneca Co., Ltd., trade names Solsperth 3000, 5000, 9000, 12000, 13240. 13940, 17000, 20000, 24000, 26000, 28000, and the like. Of these, DISPERBYK2000 manufactured by Big Chemie Japan Co., Ltd. is preferable.

  When the dispersant is used, the amount thereof may be appropriately adjusted. For example, the amount is preferably 20 to 100 parts by mass with respect to 100 parts by mass of the pigment.

(Binder)
The binder is a component that imparts film-forming properties and adhesion to the coated surface to the color filter resin composition.
As a binder, the alkali-soluble, thermosetting, or thermoplastic binder used for the coloring pixel of a conventionally well-known color filter can be used. As such a binder, for example, a binder described in JP 2010-2746 A is preferable.

Examples of the alkali-soluble binder include ethylene, which is obtained by polymerizing monomers such as acrylic acid, methacrylic acid, dimer of acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof. -Vinyl acetate copolymer, ethylene-vinyl chloride copolymer, ethylene vinyl copolymer, polystyrene, acrylonitrile-styrene copolymer, ABS resin, polymethacrylic acid resin, ethylene methacrylic acid resin, polyvinyl chloride resin, chlorination Vinyl chloride, polyvinyl alcohol, cellulose acetate propionate, cellulose acetate butyrate, nylon 6, nylon 66, nylon 12, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinyl acetal, polyether ether Tons, polyether sulfone, polyphenylene sulfide, polyarylate, polyvinyl butyral, epoxy resins, phenoxy resins, polyimide resins, polyamide-imide resins, polyamic acid resins, polyether imide resins, phenolic resins, urea resins, and the like.
In addition, polymerizable monomers methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) acrylate, tert -Butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, 2-hydroxy Examples include ethyl methacrylate, benzyl methacrylate, styrene, α-methylstyrene, N-vinyl-2-pyrrolidone, glycidyl (meth) acrylate, and the like.
In the present invention, commercially available binders can also be used. For example, Aronix M-5600 (trade names Aronix M-5600, Aronix M-6200, Aronix M-7100 and Aronix M-9050 manufactured by Toagosei Co., Ltd.) preferable.
The molecular weight of the alkali-soluble binder is preferably 5,000 to 50,000.

Examples of the thermosetting binder include a polymer composed of a structural unit represented by formula (1) and a structural unit represented by formula (2) described in JP 2010-2746 A (binder epoxy resin). ) Is preferred.
The molecular weight of the thermosetting binder is preferably 5,000 to 100,000.

  In the present invention, the alkali-soluble binder or the thermosetting binder may be used alone or in combination of two or more.

(Polymerization initiator)
When using an alkali-soluble or thermosetting binder as the binder for the color filter resin composition, it is preferable to use a polymerization initiator from the viewpoint of promoting the curing reaction.
The polymerization initiator may be appropriately selected and used depending on the type of curable group possessed by the binder. For example, a photopolymerization initiator and a thermal polymerization initiator described in Patent Document 1 and Japanese Patent Application Laid-Open No. 2007-70342 can be used.
As the photopolymerization initiator, for example, 2,2′-azobisisobutyronitrile (AIBN), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one and the like are preferable. .

  Examples of commercially available photopolymerization initiators include trade names Irgacure 184, 369, 651, 819, and 907 manufactured by Ciba Specialty Chemicals Co., Ltd., and Darocur series manufactured by Merck. Can be mentioned.

  When a polymerization initiator is used, the amount thereof may be adjusted as appropriate. For example, the amount is preferably 1 to 20% by mass relative to the total mass of the total solid content of the color filter resin composition.

(Curing agent)
The thermosetting binder is usually combined with a curing agent. As a hardening | curing agent, what is used in combination with a conventionally well-known thermosetting binder can be used.
As the curing agent, for example, a curing agent described in JP 2010-2746 A is preferable.
A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type.
When the curing agent is used, the blending amount is usually in the range of about 1 to 100 parts by mass, preferably 5 to 50 parts by mass, per 100 parts by mass of the component having an epoxy group.

(catalyst)
When using a thermosetting binder, in order to improve the hardness and heat resistance of a colored pixel, you may use the catalyst which can accelerate | stimulate the thermosetting reaction between an acid and an epoxy. As such a catalyst, a thermal latent catalyst that exhibits activity during heat curing can be used.
The heat-latent catalyst exhibits catalytic activity when heated, accelerates the curing reaction and gives good properties to the cured product, and is added as necessary. The thermal latent catalyst is preferably one that exhibits acid catalytic activity at a temperature of 60 ° C. or higher. As such, a compound obtained by neutralizing a protonic acid with a Lewis base, a compound obtained by neutralizing a Lewis acid with a Lewis base, Lewis Examples thereof include a mixture of an acid and a trialkyl phosphate, sulfonic acid esters, onium compounds, and the like, and various compounds described in JP-A-4-218561 can be used.
The blending amount in the case of using the heat latent catalyst is usually about 0.01 to 10.0 parts by mass with respect to 100 parts by mass in total of the thermosetting binder and the curing agent.

(solvent)
In order to adjust the viscosity, pigment dispersibility, and dispersion stability over time of the resin composition for a color filter, a solvent can be used as necessary.
Examples of the solvent include alcohols such as isopropanol described in Patent Document 1, ketones such as acetone and methyl ethyl ketone, aromatic hydrocarbons such as toluene and xylene, diethylene glycol dimethyl ether (also known as bis (2-methoxyethyl) ether). Glycol ethers such as propylene glycol monomethyl ether (also known as 1-methoxypropan-2-ol) and ethyl acetate, propylene glycol monomethyl ether acetate (also known as 2-methoxy-1-methylethyl acetate), propylene glycol monoethyl ether acetate ( Also known as 2-ethoxy-1-methylethyl acetate), 3-methoxybutyl acetate (also known as 3-methoxybutyl acetate) and butyl carbitol acetate (also known as 2- (2-butoxyethoxy acetate) Ethyl) acetate esters such as and the like.
Of these, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and 3-methoxybutyl acetate are preferred.

  When the solvent is used, the amount thereof may be adjusted as appropriate. For example, the amount is preferably 10 to 90% by mass with respect to the total mass of the color filter resin composition.

(Other ingredients)
The color filter resin composition may contain various other components as required without departing from the spirit of the present invention.
For example, a pigment derivative may be included as long as the effects of the present invention are not impaired. Such a pigment derivative is a compound having a role of imparting a functional group to the pigment skeleton and adding various functions to the pigment. When a pigment derivative is added to the pigment at the time of pigment dispersion, the pigment-like skeleton of the pigment derivative is adsorbed or bonded to the pigment surface, so that the surface of the pigment has polarity, so that the affinity between the dispersant and the pigment is increased. It is considered that the dispersibility and dispersion stability can be secured. Examples of the pigment derivative include a derivative having a sulfonic acid group, a carboxyl group, a sulfonamide group, a phthalimidomethyl group, or the like in the above blue pigment or yellow pigment.

In addition to the pigment derivative, for example, a polymerization terminator, a chain transfer agent, a leveling agent, a plasticizer, a surfactant, an antifoaming agent, a silane coupling agent, an ultraviolet absorber, an adhesion promoter, and the like can be used.
Among these, surfactants that can be used include, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene Examples include glycol dilaurate, polyethylene glycol distearate, sorbitan fatty acid esters, fatty acid-modified polyesters, and tertiary amine-modified polyurethanes. In addition, a fluorosurfactant can also be used.
Furthermore, examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, and tricresyl. Examples of the antifoaming agent and leveling agent include silicon-based, fluorine-based, and acrylic compounds.

(Preparation of resin composition for color filter)
The color filter resin composition may be prepared by uniformly dissolving or dispersing a coloring material, a binder, and other components such as a pigment dispersant and a polymerization initiator that are used as desired in a solvent. There is no particular limitation, and it can be prepared by mixing using a known mixing means.
As a method for preparing a resin composition for a color filter, for example, as described in JP 2010-243604 A, a method in which the desired component is mixed in a solvent using a dispersing machine such as a ball mill is used. be able to.

(Method for forming colored pixels)
The method for forming the colored pixel is not particularly limited, and may be formed by using the color filter resin composition by, for example, a pixel forming method such as a conventionally known photolithography method described in Patent Document 1.
For example, when the color filter resin composition includes a photocurable binder, the color filter resin composition is applied to the application target surface (region) by an inkjet method or a spin coating method, and then is applied by ultraviolet rays through a photomask. After exposure (pattern exposure), the unexposed portion can be formed by washing (developing) with a solvent, an alkaline aqueous solution such as an aqueous potassium hydroxide solution, or the like. After applying the resin composition, heat treatment (pre-baking) may be performed before exposure. Further, heat treatment may be performed after development.

(Shading part)
The light shielding unit 30 is provided so as to surround the colored pixels 21 to 23 and the outside of the pixel formation region in order to improve the contrast of the display image. What is used for the conventionally well-known color filter can be employ | adopted for a light-shielding part.
The light shielding unit 30 may be a metal thin film such as chromium by sputtering, vacuum deposition, or the like. In addition, the light shielding part 30 may be a resin layer in which light shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments are contained in a binder.
The thickness of the light shielding part is about 100 to 400 nm in the case of a metal thin film, and about 0.5 to 2.5 μm in the case of a resin layer containing light shielding particles.

FIG. 2 is a cross-sectional view schematically showing another example of the color filter for LED light source according to the present invention.
The LED light source color filter of FIG. 2 includes a protective film 40 formed to cover the colored pixels 21 to 23 in addition to the LED light source color filter 1 of FIG. Further, a transparent electrode film 50 for driving liquid crystal is formed on the protective film 40. An alignment film 60 is formed on the transparent electrode film 50.
The columnar spacer 70 has a shape of a convex spacer, and is formed at a plurality of predetermined positions on the transparent electrode film 50 in accordance with a region (non-display region) where the light shielding portion 30 is formed.
Hereinafter, the protective film, the transparent electrode film, the alignment film, and the spacer will be described.

(Protective film)
The protective film 40 is provided to flatten the surface of the color filter and prevent the components contained in the colored pixels 21 to 23 from eluting into other layers. The protective film 40 is formed by coloring a known negative-type photocurable resin composition or thermosetting resin composition having known transparency by a method such as spin coater, roll coater, spray, printing, and the like. It can form by apply | coating so that the light-shielding part 30 may be covered, and hardening with light and / or a heat | fever.
The thickness of the protective film 40 can be set in consideration of the light transmittance of the material used, the surface state of the color filter, and the like, and can be set, for example, in the range of 0.1 to 2.0 μm.

(Transparent electrode film)
The transparent electrode film 50 can be formed using indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof. The thickness of the transparent electrode film can be about 20 to 500 nm, preferably about 80 to 300 nm.

(Alignment film)
The alignment film 60 can be formed by applying a coating solution containing a resin such as a polyimide resin by a known method such as spin coating, drying, curing with heat or light as necessary, and then rubbing. .

(Spacer)
A plurality of spacers are provided in a non-display area on the substrate in order to maintain a cell gap when the color filter is bonded to a liquid crystal driving side substrate such as a TFT array substrate. The shape and dimensions of the spacer are not particularly limited as long as the spacer can be selectively provided in a non-display region on the substrate and a predetermined cell gap can be maintained over the entire substrate.
When the columnar spacer 70 as shown in the figure is formed as the spacer, it has a constant height in the range of about 2 μm to 10 μm, and the protruding height (pattern thickness) is the thickness required for the liquid crystal layer, etc. Can be set as appropriate. The thickness of the columnar spacer 70 can be appropriately set within a range of about 5 to 20 μm. The formation density (density) of the columnar spacers 70 can be appropriately set in consideration of the thickness unevenness of the liquid crystal layer, the aperture ratio, the shape and material of the columnar spacers, for example, red, green and blue Necessary and sufficient spacer functions are expressed at a ratio of one for each set of colored pixels. The shape of such a columnar spacer is not particularly limited, and may be, for example, a columnar shape, a prismatic shape, a truncated cone shape, or a truncated pyramid shape.

  The spacer is applied, for example, directly on the transparent substrate by a method such as a spin coater, roll coater, spray, or printing, or through another layer such as a transparent electrode film, by applying a coating liquid of the curable resin composition, Dry to form a resin layer.

As a white light emitting diode light source (white LED light source) used in combination with the color filter according to the present invention, a blue LED element and a red / green phosphor (hereinafter sometimes referred to as “RG phosphor”) are combined and white. An LED light source that generates light (hereinafter sometimes referred to as “LED (B-RG)”), a blue LED element and an yttrium aluminum garnet phosphor (hereinafter also referred to as “YAG phosphor”). Preferably, an LED light source that generates white light by combining (hereinafter also referred to as “LED (B-YAG)”) is preferably used.
Compared to the case where white light is generated by combining a blue LED element, red LED element, and green LED element, the case where white light is generated by combining the blue LED element and the RG phosphor or YAG phosphor is better. In addition, the white LED light source can be reduced in price and size.
The white LED light source used in the present invention is composed of an arbitrary number of white light emitting diode elements depending on the image display area of the display device and other specifications. In general, the larger the image display area, the greater the number of white LED elements incorporated into one white LED light source, but there may be a case where it consists of only one white LED element.
Usually, the LED element such as a blue LED element that is the base of the white LED element often has a maximum value at a wavelength of 430 to 450 nm as a whole white LED light source because the emission spectrum often deviates from the standard value by about 10 nm. In many cases, the variation (σ) of the maximum wavelength as the whole white LED light source from the standard value of the maximum wavelength of the white LED element constituting the light source is 3 or more.
As described above, in the color filter according to the present invention, the emission spectrum of the blue LED element is shifted by about 10 nm, and the white LED light source as a whole has a maximum value at a wavelength of 430 to 450 nm. Even when the maximum wavelength variation (σ) of the entire white LED light source from the standard value is 3 or more, the average transmittance at a wavelength of 430 to 460 nm of the blue pixel of the color filter corresponding to the maximum value is 80. By setting the ratio to at least%, the color shift of the display image is reduced.

The RG phosphor may be any phosphor that absorbs blue light and emits red fluorescence and green fluorescence. For example, a conventionally known RG phosphor described in Patent Document 1 or Japanese Patent Application Laid-Open No. 2003-141905 is used. Can be used.
The YAG phosphor may be any phosphor that absorbs blue light and emits yellow fluorescence and green fluorescence. For example, a conventionally known YAG phosphor described in Patent Document 1 or Japanese Patent Application Laid-Open No. 2008-218486 is used. Can be used.

A display device according to the present invention includes a white light emitting diode light source and the color filter for the white light emitting diode light source.
Since the display device according to the present invention includes the color filter, even when combined with a white LED light source, the display device has a contrast equal to or higher than that when combined with a CCFL light source, and is excellent in display quality.

Examples of such a display device include a liquid crystal display device and an organic electroluminescent (organic EL) display device.
Hereinafter, a liquid crystal display device and an organic EL display device will be described.

FIG. 3 is a cross-sectional view schematically showing an example of a liquid crystal display device as a display device of the present invention.
In the liquid crystal display device, for example, a gap portion 90 of about 1 to 10 μm is provided by facing the color filter of the present invention and an electrode substrate 80 such as a TFT substrate, and the liquid crystal compound L is filled in the gap portion 90. , And the periphery thereof is sealed with a sealing material 100.
An alignment film 60 is provided on the inner surface side of the electrode substrate 80 facing the color filter 1. Usually, a white LED light source is disposed at a position opposite to the colored pixels 21 to 23 of the color filter 1 through a liquid crystal layer of a liquid crystal compound.

A driving method of the liquid crystal display device is not particularly limited, and a driving method used in a general liquid crystal display device can be employed. Examples of such a drive method include a TN method, an IPS method, an OCB method, and an MVA method. In the present invention, any of these methods can be preferably used.
The electrode substrate 80 facing the color filter 1 can be appropriately selected and used according to the driving method of the liquid crystal display device.
Furthermore, as the liquid crystal compound L filled in the gap portion 90, various liquid crystals having different dielectric anisotropy and mixtures thereof can be used according to the driving method of the liquid crystal display device of the present invention.

  The liquid crystal display device may include other optical members such as a light guide plate, a diffusion plate, and a prism sheet in addition to the above-described members.

(Organic EL display device)
The organic EL display device includes the above-described color filter of the present invention and an organic light emitter that serves as a white LED light source.
FIG. 4 is a cross-sectional view schematically showing an example of an organic EL display device as a display device of the present invention. The organic EL display device 3 includes a color filter 1 and an organic light emitter 120 (LED light source 110).
An organic protective layer 41 and an inorganic oxide film 130 may be provided between the color filter 1 and the organic light emitter 120.

As a method for laminating the organic light emitter 120, for example, the transparent anode 140, the hole injection layer 150, the hole transport layer 160, the light emitting layer 170, the electron injection layer 180, and the cathode 190 are sequentially formed on the upper surface of the color filter. Examples thereof include a method and a method in which the organic light-emitting body 120 formed on another substrate is bonded to the inorganic oxide film 130. As the transparent anode 140, the hole injection layer 150, the hole transport layer 160, the light emitting layer 170, the electron injection layer 180, the cathode 190, and other configurations in the organic light emitting body 120, known configurations can be appropriately used. The organic light emitting display device 3 thus manufactured can be applied to, for example, a passive drive type organic EL display device or an active drive type organic EL display device.
Note that the organic EL display device of the present invention is not limited to the configuration shown in FIG. 4, and can generally have a known configuration as an organic EL display device using a color filter.

  As a method for manufacturing a display device according to the present invention, any method may be used as long as the above-described components are stacked with high accuracy. Depending on the type of the display device, a general liquid crystal display device or an organic EL display device may be used. Manufacturing methods can be used.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and this embodiment has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples. These descriptions do not limit the present invention.

The abbreviations of the compounds used in the synthesis examples are as shown in parentheses.
Methyl methacrylate (MMA)
Acrylic acid (AA)
2-hydroxyethyl methacrylate (HEMA)
Diethylene glycol dimethyl ether (DMDG)
2,2'-azobisisobutyronitrile (AIBN)
Glycidyl methacrylate (GMA)

(Synthesis Example 1)
In a polymerization tank, 63 parts by mass of MMA, 12 parts by mass of AA, 6 parts by mass of HEMA and 88 parts by mass of DMDG were charged, stirred and dissolved, and then 7 parts by mass of AIBN was added and dissolved uniformly. Then, it stirred at 85 degreeC under nitrogen stream for 2 hours, and also was made to react at 100 degreeC for 1 hour. 7 parts by mass of GMA, 0.4 parts by mass of triethylamine and 0.2 parts by mass of hydroquinone were further added to the obtained solution, and the mixture was stirred at 100 ° C. for 5 hours to obtain a copolymer resin solution (solid content 50%). It was.

The following materials were mixed and stirred at room temperature to obtain a curable resin composition as a binder.
The above copolymer resin solution (solid content 50%): 16 parts by mass Dipentaerythritol pentaacrylate (trade name SR399 manufactured by Sartomer): 24 parts by mass Orthocresol novolak type epoxy resin (Product made by Yuka Shell Epoxy Co., Ltd.) Name Epicoat 180S70): 4 parts by mass 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (trade name Irgacure 907 manufactured by Ciba Specialty Chemicals Co., Ltd.): 4 parts by mass Parts DMDG: 52 parts by mass

Example 1
(1) Preparation of Blue Color Filter Resin Composition 1 The following materials were mixed and stirred at room temperature to prepare a blue pixel color filter resin composition 1.
(Composition of resin composition 1 for blue color filter)
PB1: 2.9 parts by mass The curable resin composition (binder): 8.8 parts by mass Polymer dispersant (trade name DISPERBYK2000 manufactured by Big Chemie Japan Co., Ltd.): 14.7 parts by mass 3-methoxybutyl acetate (Solvent): 73.5 parts by mass

(2) Preparation of blue color filter 1 Using the spin coater, the resin composition 1 for blue color filter prepared above is formed on a glass substrate (NH Techno Glass Co., Ltd., "NA35") having a thickness of 0.7 mm. And applied. Then, it heat-dried for 3 minutes on an 80 degreeC hotplate. The blue color filter 1 was obtained by irradiating 60 mJ / cm < ² > of ultraviolet-rays using an ultrahigh pressure mercury lamp, and post-baking for 30 minutes in a 230 degreeC clean oven.
The film thickness of the blue color filter 1 after curing was adjusted so that the target chromaticity x = 0.144 and y = 0.100 (C light source).

(3) Light source used The “unsorted light source” group consisting of 10 randomly selected white light emitting diode element product stocks having a maximum wavelength as a standard value of 440 nm was used as the light source of Example 1. . The standard deviation (σ) of the maximum wavelength variation of this unselected light source was 4.
(4) Irradiation experiment For the same blue color filter 1, individual unselected light sources (that is, individual white light emitting diode elements) belonging to a group of 10 unselected light sources are combined one by one as a backlight light source. A street sample was prepared, and an irradiation experiment was performed on each sample.
Further, for the same blue color filter 1, a white light emitting diode element satisfying a standard value (maximum wavelength is a standard value of 440 nm) is combined as a standard light source, and a standard sample of Example 1 is created. An irradiation experiment was also conducted on the sample.

(Example 2)
(1) Preparation of Blue Color Filter Resin Composition 2 The following materials were mixed and stirred at room temperature to prepare a blue pixel color filter resin composition 2.
(Composition of resin composition 2 for blue color filter)
PB62: 2.9 parts by mass The curable resin composition (binder): 8.8 parts by mass Polymer dispersant (trade name DISPERBYK2000 manufactured by Big Chemie Japan Co., Ltd.): 14.7 parts by mass 3-methoxybutyl acetate (Solvent): 73.5 parts by mass

(2) Preparation of blue color filter 2 In Example 1, a blue color filter was obtained in the same manner as in Example 1 except that the blue color filter resin composition 2 was used instead of the blue color filter resin composition 1. 2 was obtained.
(3) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 unselected light sources (standard deviation (σ) = 4 of maximum wavelength variation) as in Example 1, and the same as in Example 1. An irradiation experiment was performed for each sample.
Further, a reference sample of Example 2 was prepared by combining the blue color filter 2 with the same reference light source as in Example 1, and an irradiation experiment was also performed on this reference sample.

(Example 3)
(1) Preparation of Blue Color Filter Resin Composition 3 The following materials were mixed and stirred at room temperature to prepare a blue pixel color filter resin composition 3.
(Composition of resin composition 3 for blue color filter)
BasicBlue 7: 2.4 parts by mass The above curable resin composition (binder): 9.4 parts by mass Polymer dispersant (trade name DISPERBYK2000 manufactured by Big Chemie Japan Co., Ltd.): 14.7 parts by mass 3-methoxybutyl acetate (Solvent): 73.5 parts by mass

(2) Preparation of blue color filter 3 In Example 1, a blue color filter was prepared in the same manner as in Example 1 except that the blue color filter resin composition 3 was used instead of the blue color filter resin composition 1. 3 was obtained.
(3) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 unselected light sources (standard deviation (σ) = 4 of maximum wavelength variation) as in Example 1, and the same as in Example 1. An irradiation experiment was performed for each sample.
Further, a reference sample of Example 3 was prepared by combining the blue color filter 3 with the same reference light source as in Example 1, and an irradiation experiment was also performed on this reference sample.

(Comparative Example 1)
(1) Preparation of Blue Color Filter Resin Composition 4 The following materials were mixed and stirred at room temperature to prepare a blue pixel color filter resin composition 4.
(Composition of resin composition 4 for blue color filter)
PB15: 6: 2.4 parts by mass PV23: 0.6 parts by mass The above-mentioned curable resin composition (binder): 8.8 parts by mass Polymer dispersant (trade name DISPERBYK2000 manufactured by Big Chemie Japan Co., Ltd.): 14 0.7 part by mass 3-methoxybutyl acetate (solvent): 73.5 parts by mass

(2) Preparation of blue color filter 4 In Example 1, except that the blue color filter resin composition 4 was used instead of the blue color filter resin composition 1, the same procedure as in Example 1 was repeated. A blue color filter 4 was obtained.
(3) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 unselected light sources (standard deviation (σ) = 4 of maximum wavelength variation) as in Example 1, and the same as in Example 1. An irradiation experiment was performed for each sample.
In addition, a reference sample of Comparative Example 1 was prepared by combining the blue color filter 4 with the same reference light source as in Example 1, and an irradiation experiment was also performed on this reference sample.

(Reference Example 1)
(1) Color filter used In the same manner as in Example 1, a blue color filter 1 was prepared using the resin composition 1 for blue color filter and used for evaluation of Reference Example 1.
(2) Light source used From the product stock of white light emitting diode elements (maximum wavelength is 440 nm as a standard value) which is the same standard product as the example, 10 white light emitting diode elements with small individual differences of the maximum wavelength are selected. The configured “sorted light source” group was used as the light source of Reference Example 1. The standard deviation (σ) of the maximum wavelength variation of this selected light source was 2.
(4) Irradiation experiment For the same blue color filter 1, 10 individual light sources (that is, individual white light-emitting diode elements) belonging to a group of 10 light sources are combined as backlight light sources one by one. Samples were prepared and irradiation experiments were performed on each sample.
In addition, the reference sample of Example 1 was used as the reference sample of Reference Example 1, and the result of the irradiation experiment obtained in Example 1 was shared.

(Reference Example 2)
(1) Color filter used In the same manner as in Example 2, a blue color filter 2 was prepared using the resin composition 2 for blue color filter, and used for evaluation of Reference Example 2.
(2) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 selection light sources (standard deviation (σ) = 2 of maximal wavelength variation) as in Example 1, and each was similar to Reference Example 1. An irradiation experiment was performed on the sample.
Further, as the reference sample of Reference Example 2, the reference sample of Example 2 was used, and the result of the irradiation experiment obtained in Example 2 was shared.

(Reference Example 3)
(1) Color filter used In the same manner as in Example 3, a blue color filter 3 was prepared using the resin composition 3 for blue color filter and used for evaluation of Reference Example 3.
(2) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 selection light sources (standard deviation (σ) = 2 of maximal wavelength variation) as in Example 1, and each was similar to Reference Example 1. An irradiation experiment was performed on the sample.
Further, as the reference sample of Reference Example 3, the reference sample of Example 3 was used, and the result of the irradiation experiment obtained in Example 3 was shared.

(Reference Example 4)
(1) Used color filter The blue color filter 4 was created using the resin composition 4 for blue color filters similarly to the comparative example 1, and was used for evaluation of the reference example 2. FIG.
(2) Light source used and irradiation experiment Ten types of samples were prepared using the same 10 selection light sources (standard deviation (σ) = 2 of maximal wavelength variation) as in Example 1, and each was similar to Reference Example 1. An irradiation experiment was performed on the sample.
Further, as the reference sample of Reference Example 4, the reference sample of Comparative Example 1 was used, and the result of the irradiation experiment obtained in Comparative Example 1 was shared.

  Table 1 shows a summary of the compositions of the blue color filter resin compositions 1-4.

  Table 2 shows information on the light source used.

(Evaluation method)
In each experimental example (Examples 1 to 3, Comparative Example 1, Reference Examples 1 to 4), an irradiation experiment was performed on 10 samples and a reference sample, and the x value, y value, Y value and The spectrum was measured using a spectroradiometer (product type number: SR-3) manufactured by Topcon Corporation.
The color difference ΔE * ab (color shift from the reference sample) was calculated for each sample from the measured value of each sample and the measured value of the reference sample using the following mathematical formula (1).
For each experimental example (including 10 samples each), the standard deviation of the color difference (color shift) from the reference sample is calculated using the ΔE * ab value and the following mathematical formula (2), and the calculated standard deviation value is Evaluation was made based on the following evaluation criteria.

(Evaluation criteria)
Good (◯): Standard deviation is less than 3.
Defect (x): Standard deviation is 3 or more.

Table 3 summarizes the evaluation results. In Examples 1 to 3, the standard deviation of color difference was less than 3, whereas in Comparative Example 1, the standard deviation of color difference was 3 or more.
Reference Examples 1 to 4 correspond to Examples 1 to 3 and Comparative Example 1, respectively, but use selective light sources with small variations in light sources. In Comparative Example 1 and Reference Example 4, the same color filter 4 (resin composition 4 for blue color filter) was used, but in Reference Example 4 using a light source with small variation, the standard deviation of the color difference was as small as 2.17. While the evaluation result was good (◯), in Comparative Example 1 using a light source with large variation, the standard deviation of the color difference was as large as 5.21, and the evaluation result was poor (×).

DESCRIPTION OF SYMBOLS 1 Color filter for LED light source 2 Liquid crystal display device 3 Organic EL display device 10 Transparent substrate 21 Red pixel 22 Green pixel 23 Blue pixel 30 Light-shielding part 40 Protective film 41 Organic protective film 50 Transparent electrode film 60 Alignment film 70 Spacer 80 Electrode substrate 90 Gaps (Liquid Crystal Compound L)
DESCRIPTION OF SYMBOLS 100 Sealing material 110 LED light source 120 Organic light-emitting body 130 Inorganic oxide film 140 Transparent anode 150 Hole injection layer 160 Hole transport layer 170 Light emitting layer 180 Electron injection layer 190 Cathode

Claims (4)

A white light emitting diode light source color filter having at least a red pixel, a green pixel and a blue pixel,
A white light emitting diode having an average transmittance of 80% or more at a wavelength of 420 to 460 nm of a blue pixel, an emission spectrum having a maximum value at a wavelength of 430 to 450 nm, and a variation (σ) of the maximum value wavelength being 3 or more A color filter for a white light-emitting diode light source, which is used for a light source.   2. The color filter for a white light emitting diode light source according to claim 1, wherein a difference between a maximum value and a minimum value of transmittance of the blue pixel at a wavelength of 420 to 460 nm is 10% or less. A white light emitting diode light source having a maximum value of an emission spectrum at a wavelength of 430 to 450 nm, and having a maximum wavelength variation (σ) of 3 or more;
A display device comprising: the white light-emitting diode light source color filter according to claim 1.   The display device according to claim 3, wherein the number of light emitting diode elements included in the white light emitting diode light source is 4 to 100.

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