JP2003207770A - Color filter for liquid crystal display and liquid crystal display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter for liquid crystal display which enables a liquid crystal display to have a color reproduction region equal to or more than a color reproduction region of standard values of the NTSC (national TV system commities) system of a color CRT on a CIE chromaticity diagram, and the liquid crystal display. <P>SOLUTION: The color liquid crystal display which uses light emitting diodes of blue, green, and red as color light sources of a back light and also uses color filters of blue, green, and red. Disclosed are the color filter, characterized in that peak wavelengths of the light emitting diodes are 430 to 480 nm for blue, 520 to 570 nm for green, and 620 to 660 nm for red and the spectral transmissivity of the color filter at the peak wavelengths of blue, green, and red of the light emitting diodes is ≥80% for blue, red, and green, and the liquid crystal display which uses such color filters. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter for a liquid crystal display device, and more particularly to a color filter for a liquid crystal display device having a color reproduction range equivalent to that of a color cathode ray tube (CRT) and a color liquid crystal using the same. Regarding display device.

[0002]

2. Description of the Related Art Color liquid crystal display devices are expected to generate great demand for personal computers, particularly notebook personal computers, and further develop into desktop personal computers, monitors and television receivers for broadcasting. . A demand for a display color of a color liquid crystal display device used for a notebook personal computer, a mobile terminal, etc. is that, from the viewpoint of power consumption, the saturation, that is, the transmittance (lightness) is high even if the color reproduction range is slightly inferior. Therefore, as the color filter, a color filter having a high transmittance corresponding to this demand has been demanded.

In order to meet such demands, the color filters have been improved by developing pigments, dispersants, and dispersion techniques used for the color filters, but the color reproduction range is inferior, so that the color reproduction is sufficient. For example, if you try to express deep red, it will be orange,
Even if I tried to express dark blue, it remained light blue and could not reproduce colors well. On the other hand, as for the display color of a color liquid crystal display device used for a television receiver for broadcasting, a monitor, etc., there is a demand for a wide color reproduction range with improved saturation even if the brightness (transmittance) is slightly inferior. , C
The color gamut on the IE chromaticity diagram is made to be the same as that of the color CRT.

In the color CRT for broadcasting, the shape of the object is changed through the process of image reception (color camera), transmission and image reception.
The movement and hue are reproduced on the screen. Therefore, the transmission method of the image signal including the hue is standardized. A typical example of this method is NTSC (Nation
al Television System Comm
Itte) system, and the United States, Canada, and Japan are the major countries broadcasting television by this system. On the other hand, in Europe, the EBU defines the system and standard.

The color gamut of the color CRT is determined by
It is the chromaticity of the three primary colors of the receiver, and this also determines the spectral characteristics that the color camera should have. The three image-receiving primary colors of the NTSC system are defined as follows with respect to chromaticity coordinates x and y in the XYZ color system. Red: x = 0.67; y = 0.33 Green: x = 0.21; y = 0.71 Blue: x = 0.14: y = 0.08 Note that x = X / (X + Y + Z). , Y = Y / (X +
Y + Z), and X, Y, Z are 3 in the XYZ color system.
It is a stimulus value.

The color CRT is a system in which electrons accelerated by an electron gun collide with a fluorescent substance to emit fluorescent light, and by appropriately selecting the fluorescent substance, a highly vivid color display can be obtained. Will be realized.

However, in the current color liquid crystal display device, especially in the transmissive liquid crystal display device using a color filter, first, the spectral transmittance characteristic of the color filter is restricted. However, the spectral transmittance characteristics of the current color filter have not reached the ideal one.
Further, in a transmissive liquid crystal display device using a backlight, a three-wavelength fluorescent tube is used as the backlight.
There is no choice but to be limited by the emission characteristics of this three-wavelength fluorescent tube.

Recently, it has been proposed that the emission spectral characteristic of the three-wavelength fluorescent tube is considerably good. However, as shown in FIG. 3, a gentle mountain-shaped spectrum is obtained for each of the three colors (blue, green, and red). However, the ideal steep mountain-shaped waveform or rectangular spectrum is not obtained. As described above, the reality of the color filter and the backlight makes the color screen display of the color liquid crystal display device dull.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to meet the demand for display colors of color liquid crystal display devices used in such televisions and monitors, and has a color reproduction range of CIE chromaticity. In the figure, the color CRT N
TSC (National Television Sy)
An object of the present invention is to provide a color filter for a liquid crystal display device, which enables a liquid crystal display device having a color reproduction area equal to or larger than a color reproduction area of a standard value defined by the system committee system. It is another object of the present invention to provide a liquid crystal display device having the above-mentioned color reproduction range, which uses the color filter for the liquid crystal display device.

[0010]

That is, the present invention provides a color filter for a color liquid crystal display device using a blue-green-red light-emitting diode as a color light source of a backlight, wherein the light-emitting diode has a blue-green-red color filter. 430-48 with blue peak wavelength
It is in the range of 0 nm, in the range of 520 to 570 nm for green, and in the range of 620 to 660 nm for red, and the half-value wavelength width is blue and plus or minus 1 from the peak wavelength.
A backlight having a light emission characteristic of a width of 5 nm, a width of plus or minus 20 nm for green, and a width of plus or minus 15 nm for red, and the spectral transmittance of a color filter at a peak wavelength of blue green red of the light emitting diode is blue red. It is a color filter for a liquid crystal display device, characterized in that it is 80% or more in green.

The present invention is also a color liquid crystal display device using a blue-green-red light emitting diode as a color light source of a backlight and a blue-green-red color filter, wherein the light-emitting diode has a peak wavelength of blue-green-red. Is in the range of 430 to 480 nm for blue, 520 to 570 nm for green, and 620 to 660 nm for red, and the half-value wavelength width of each is blue and the width of plus or minus 15 nm from the peak wavelength is green. It is a backlight having a light emission characteristic of a plus or minus 20 nm width and a red plus or minus 15 nm width, and the spectral transmittance of a color filter at a peak wavelength of blue green red of the light emitting diode is 80% or more for blue red green. A color liquid crystal display device characterized by the above.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. 1 and 2 are explanatory views showing an embodiment of a color liquid crystal display device 1 of the present invention. In the figure,
The light emitting diode light source 2 has a concave reflecting mirror 3 arranged behind it,
A large number of red, green, and blue are repeatedly arranged in order, and the colored light is emitted from the transparent light guide plate 5 provided on the back surface of the liquid crystal display panel 4.
Are led to the display screen of the liquid crystal display panel 4 on average. A reflection plate 6 is provided on the back surface of the light guide plate 5. Figure 1
In the embodiment, the light emitting diode light source 2 is arranged only on one side of the liquid crystal display panel 4. However, when sufficient illuminance cannot be obtained with the backlight on only one side, the light emitting diode light sources 2 may be arranged on the left and right sides of the liquid crystal display panel 4.

The liquid crystal display panel 4 is, of course, a transmissive liquid crystal display device, and although it is not clear in the figure, a transparent substrate is provided at the front and rear, and two transparent electrodes for driving the liquid crystal are provided on the inner surface thereof.
It has one color filter layer and two alignment films in contact with the liquid crystal layer. One of the transparent electrodes is divided into pixels, and each of the transparent electrodes is a thin film transistor (TF).
On / off control is generally performed by a switching element such as T). This is a so-called TFT type color liquid crystal display device.

First, FIG. 4 shows an example of emission spectral characteristics of the backlight of the light emitting diode used in the present invention. According to FIG. 4, the emission spectral characteristics of the emission die auto are sharper in a mountain shape than that of the conventional three-wavelength fluorescent tube. This enhances the color characteristics, especially the saturation, of the liquid crystal display device of the present invention.

As the light emitting diode which can be used in the present invention, three types of blue, green and red are used. To explain in color order,
For blue light emitting diodes, gallium nitride (GaN) is the main material, and specifically, sapphire substrate / n-GaN / n-Al 0.
15Ga 0.85N / MQW or SQW layer / p-Al 0.15Ga 0.85N / p-GaN
/ Electrode is an example. Here, the MQW or SQW layer means a multi quantum well structure (MQW) and a single quantum well structure (SQW). As a material, InxGa1-xN can be exemplified. When x = 0.2, a blue color is formed, and when x = 0.4, a green color is formed.

With this material, green light emission can be obtained when the In (indium) composition is increased, but the crystallinity deteriorates with the increase of the In composition, so that the light emission efficiency decreases. Use GaInN green LED as another material to ensure sufficient emission brightness, or GaInN
It is also possible to suggest using a combination of N blue LED + green phosphor. This allows the green LED to have a peak wavelength at an appropriate wavelength in the range of 520 to 570 nm.

The red LED is an AlInGaP type LED, and can obtain a satisfactory emission characteristic. In addition, there are GaAlAs red LEDs. The structure is GaAs substrate / n-GaAs / n-InGaAlP / und
oped InGaAlP / p-InGaAlP / p-GaAs / electrode. In
Of the three elements of GaAl, In is 0.5 and the lattice constant is matched with GaAs, and the emission wavelength can be changed by changing the ratio of Ga and Al. Al
If the ratio of is increased, the wavelength shifts to shorter wavelengths. Ga to 0.25, Al
Is about 0.25, red light with a wavelength of about 600 nm is emitted.

Since these LEDs are manufactured by a chemical vapor deposition method (MOCVD method) using an organic metal, the composition can be controlled relatively easily by controlling the ratio of the organic metal raw material introduced into the reaction chamber. it can. , Therefore with blue LED 430
It is relatively easy to bring the peak wavelength to an appropriate wavelength in the range of ~ 480 nm, or to bring the peak wavelength to an appropriate point in the range of 600 to 6060 nm for a red LED. That is, light emission of a desired wavelength can be obtained.

As described above, the emission spectral characteristics of the light emitting diode are steep, and the half-value wavelength width of the blue LED is plus or minus 15 nm from the peak wavelength, the green LED is plus or minus 20 nm, and the red LED is It is possible to realize light emission characteristics within a width of plus or minus 15 nm, and the characteristics of this backlight contribute to the vividness of color display of the liquid crystal display device.

On the other hand, the color filter has a spectral transmittance of 80% or more with respect to the peak wavelength of the light emitting diode in view of the physical properties of the current color filter, so that a bright screen display can be realized. If the spectral transmittance is increased to more than 80%, it is possible to easily achieve color characteristics higher than those of the NTSC system.

In order to form a filter layer of each color constituting a color filter used in the liquid crystal display device of the present invention, a photosensitive coloring composition is used and a fine matrix or mosaic is formed on a transparent substrate such as glass by photolithography. It is often formed as a thin film. In the preparation of this photosensitive coloring composition, the basic idea for each of the red, green and blue filter layers is to first select a pigment having an appropriate spectral distribution and then determine the content of the pigment contained in each color pattern. However, the content should be such that the saturation and the light transmittance are balanced so that the transmittance of each color filter layer does not drop too much. Then, by increasing the content of the pigment contained in the filter layer of each color, it is possible to reduce the film thickness of the pattern of each color at the same time, whereby the filter layer of each color formed by the photolithography method. Make sure the shape is good.

That is, according to the above concept, the saturation,
Transmittance (brightness), and to obtain a pattern of each color with a good shape, in a color filter using a light emitting diode as a backlight, near the peak wavelength of each color of the light emitting diode, high transmittance, Other hues,
That is, for the blue filter, one having good light absorption should be used in the wavelength regions of green and red. This means that for the green filter, choose one that has good light absorption in the blue and red wavelength regions, and for the red filter, choose one that has good light absorption in the blue and green wavelength regions. .

On the other hand, regarding the photosensitive coloring composition as the raw material of the color filter, the photosensitive coloring composition is constituted,
For example, of the main components such as resin, pigment, photopolymerizable monomer, and solvent, the ratio (solid content ratio) of the solid content other than the solvent to the photosensitive coloring composition is maintained at a certain value or less to obtain good coatability. I am supposed to. This is because when the solid content ratio exceeds a certain value, problems such as coating unevenness and film thickness unevenness occur in the coating film on the substrate, and these are avoided. As described above, the photosensitive coloring composition is prepared in consideration of the saturation, transmittance (brightness), and shape of the pattern of each color to be obtained, and also in consideration of coatability, dispersibility, and stability over time. It is something.

The range of colors that can be reproduced by the color CRT of the color television receiver is three chromaticities on the chromaticity diagram of the three primary colors emitted by the red (R), green (G) and blue (B) phosphors. It is inside a triangle surrounded by dots. For example, the area of a triangle on the chromaticity diagram surrounded by three chromaticity points according to the standard value of the NTSC system is the color reproduction area in the NTSC system.

The present invention is a CIE using light emitting diodes of three primary colors of red (R), green (G) and blue (B) of color filters.
It is possible to form a triangle whose chromaticity point on the chromaticity diagram includes a triangle in the NTSC color gamut and is wider than that. The color reproduction range is the standard color reproduction range of the NTSC system 1
It is possible to have a color reproduction area having an area ratio of 100% to 130% with respect to 00%.

The color filter having the above-mentioned color reproduction range according to the present invention can be obtained by forming a pattern of each color in a film thickness range of 0.8 μm to 3.0 μm using the photosensitive coloring composition described below. The photosensitive coloring composition of the present invention is prepared, for example, by kneading into a chip by using a two-roll in order to mix the acrylic resin and the pigment well, and then the chip is dissolved using a dispersant and a solvent. To produce a colored resin (paste). Next, a photopolymerizable monomer and a photopolymerizable initiator are added to this colored resin (paste) to prepare a photosensitive colored composition.

The acrylic resin used at this time is an alkyl acrylate or alkyl methacrylate such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate or butyl methacrylate, cyclic cyclohexyl acrylate or methacrylate, A resin synthesized to have a molecular weight of about 5,000 to 100,000 using about 3 to 5 types of monomers such as hydroxyethyl acrylate or methacrylate is used. In addition, by reacting a compound obtained by adding an unsaturated double bond to a part of an acrylic resin, the above acrylic resin, an isocyanate ethyl acrylate having an isocyanate group and at least one or more vinyl groups, a methacryloyl isocyanate, etc. Obtained acid value 50-1
Fifty photosensitive copolymers can be used.

As the pigment, C.I. I. N
o. 9, 97, 122, 123, 149, 168, 17
7, 180, 192, 215, 254, 264 and the like are preferable. As green (G), C.I. I. No. 7, 36 can be given. As blue (B), C.I. I. No. 15, 22, 6
0 and 64 are commonly used. Pigment No. is yellow. 13, 83, 138, 139, 150 and the like, among which isoindoline type, monoazo Ni complex type, and azo type are preferable. Green is a copper phthalocyanine halide, blue is a copper phthalocyanine-based,
The crystal structure is preferably α, β or ε type. As purple, C.I. I.
No. 23 is used. Further, especially in the case of red pigments, anthraquinone type (A2B, A3B manufactured by Ciba-Geigy) is used.
Etc.), diketopyrrolopyrrole (Ciba-Geigy, B-
(CF, orange TR, rubin TR, etc.) and perylene are preferably used, but not limited thereto.

Further, in order to disperse the pigment particles uniformly in the photosensitive coloring composition, it is preferable to use a dispersant. As the dispersant, a wide range of dispersants such as surfactants, intermediates of pigments, intermediates of dyes and sol-spars are used. Preferably, it is a derivative of an organic dye, and as a base organic dye, an azo type, a phthalocyanine type, a quinacridone type, an anthraquinone type, a perylene type, a thioindico type,
Gioxane-based and pyrrole-based metal complex salts. The amount of such a dispersant added is small, and is about 1 to 5% by weight based on the pigment.

The photopolymerizable monomer includes bifunctional, trifunctional and polyfunctional monomers, and as the bifunctional monomer,
There are 1,6-hexanediol diacrylate, ethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, etc., and as trifunctional monomers, trimethylolpropane triacrylate, pentaerythritol triacrylate, tris (2-hydroxy). Ethyl) isocyanate and the like, and polyfunctional monomers include ditrimethylolpropane tetraacrylate, dipentaerythritol penta and hexaacrylate. These monomers include commercial products such as Showa High Polymer Co., Ltd., Toagosei Co., Ltd., Nippon Kayaku Co., Ltd., and the like. The addition amount of the photopolymerizable monomer is not particularly limited,
It is about 20 to 150 parts by weight of the acrylic resin for dispersion.

As the solvent, methanol, ethanol,
Toluene, xylene, ethyl cellosolve, ethyl cellosolve acetate, diglyme, cyclohexanone, ethylbenzene, isomil acetate, mamyl acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol, Resins such as triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, ethyl lactate are used. Monomer composition, photopolymerizable monomer, Since solubility or the like polymerization initiator differs appropriately selecting the solvent for single or multiple solvent composition.

As the photopolymerization initiator, conventional triazine compounds, 2,4,6-tris (trichloromethyl) -S-triazine and 2- (p-methoxystyryl) are used.
-4,6-Pis (trichloromethyl) -S-triazine, 2-phenyl-4,6-bis (trichloromethyl)
-S-triazine, 2- (p-methoxyphenyl)-
4,6-bis (trichloromethyl) -S-triazine,
2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (4'-methoxy-1'-naphthyl) -4,6-his (trichloromethyl)
A mixed system such as -S-triazine may be used.

Further, as the acetophenone compound, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, diethoxyacetophenone, 2-hydroxy-2-methyl-1-enyl (4-dodecyl) propane- 1-on, etc. Examples of the benzophenone compound include benzophenone, 4,4-diethylaminobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, and 0-benzophenone methyl benzoate. As thioxanthone compounds,
2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone and the like.

As the imidazole compound, 2
-(2,3-Dichlorophenyl) -4,5-diphenyl-imidazole dimer, 2- (2,3-dichlorophenyl) -4,5-bis (3-methoxyphenyl) -imidazole dimer, 2 -(2,3-dichlorophenyl)-
4,5-bis (4-methoxyphenyl) -imidazole dimer, 2- (2,3-dichlorophenyl) -4,5-
Bis (4-chlorophenyl) -imidazole dimer, 2
-(2,3-Dichlorophenyl) -4,5-di (2-furyl) -imidazole, 2,2'-bis (2-chlorophenyl) -4,5,4 ', 5'-tetraphenyl-1-
2'-biimidazole, HB22 (Hodogaya Chemical Co., Ltd.) and the like.

The addition amount of the photopolymerization initiator is not particularly limited, but the addition amount when one type or two types of the triazine compound is used is 5 to 5 of the photopolymerizable monomer.
50 parts by weight, preferably 10 to 30 parts by weight are used by adding one or two kinds. When the triazine compound is mixed with another photopolymerization initiator, the triazine compound is added in an amount of 1 to 50 parts by weight, preferably 5 to 30 parts by weight of the photopolymerizable monomer, a benzophenone compound, Regarding the thioxanthone compound and the imidazole compound, 1 to 40 parts by weight, preferably 5 parts by weight of the photopolymerizable monomer is used.
~ 20 parts by weight.

[0036]

EXAMPLES Example 1 (Preparation of Photosensitive Coloring Composition) Acrylic resin (20 parts of methacrylic acid, 30 parts of butyl acrylate, 50 parts of butyl methacrylate) was dissolved in 300 parts of ethyl cellosolve, and azobis was added under a nitrogen atmosphere. 0.75 parts of isobutyl nitrile was added and the acrylic resin obtained by the reaction at 70 ° C. for 5 hours was diluted with ethyl cellosolve so that the resin concentration became 20%. 12.3 g of pigment to 50 g of this diluted resin,
1.3 g dispersant, 36.4 cyclohexanone as solvent
g was added and sufficiently kneaded with a three-roll mill to prepare a red colored resin (paste). Similarly, 15 g of the pigment, 1.1 g of the dispersant, and 38.9 g of cyclohexanone as a solvent were added to 45 g of the diluted resin, and the mixture was sufficiently kneaded with a three-roll mill to produce a green colored resin (paste). And, to 50 g of the diluted resin, 9.5 g of pigment and 1.0 of dispersant
g, and 39.5 g of cyclohexanone as a solvent were added and sufficiently kneaded with a three-roll to prepare a blue colored resin (paste).

The pigments are shown below. [For Red] 12 g of pigment B-CF (DPP pigment CI Pigment Red 254 manufactured by Ciba-Geigi) and A2B (C. Pigment-made C.I.
I. Pigment Red 177) A mixture with 0.3 g.

[For green] 10.4 g of pigments Lionol Green 6YK (CI Pigment Green 36 manufactured by Toyo Ink Mfg. Co., Ltd.) and 5GN
(Bayer CI Pigment Yellow 150)
4.6 g of the mixture. Copper phthalocyanine derivative CuPC [SO2N (C18H37) 2] 2 as a dispersant

[For blue] Pigment lionol blue ES (C.I. manufactured by Toyo Ink Mfg. Co., Ltd.)
I. Pigment Blue 15: 6) 9.0 g and 5 g of Rionogen Violet HR (CI Pigment Violet 23 manufactured by Toyo Ink Mfg. Co., Ltd.).

To 50 g of each colored resin (paste), 5 g of dipentaerythritol pentaacrylate, 0.8 g of 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, methoxystyryltriazine. 0.2 g, diluted resin 3 synthesized earlier
g, and propylene glycol dimethyl acetate 4
1 g was added and well stirred to prepare a photosensitive coloring composition of each color.

(Production of Color Filter) First, a red photosensitive coloring composition was spin-coated on a substrate having a black matrix formed thereon and dried. After prebaking at 70 ° C. for 20 minutes, 400 mJ / cm 2 exposure was performed using a mask having the same pixel size as one pixel of the liquid crystal display element. It was developed with an aqueous solution of 2.5% sodium carbonate, washed with water, further washed with water, dried and then dried at 230 ° C. for 30 minutes to solidify the pattern. The film thickness after baking was 1.2 μm. Next, the green photosensitive coloring composition was spin-coated and dried. Thereafter, a green pattern having a film thickness of 1.2 μm was obtained by the same process as for red.
Furthermore, the blue photosensitive coloring composition was spin-coated and dried. Thereafter, a blue pattern having a film thickness of 1.2 μm was obtained by the same process as the previous color.

Using this color filter, ITO having a thickness of 140 nm was formed on the color filter and dried at 220 ° C. for 1 hour, and then an alignment film was applied to 50 nm and dried. A part of the TFT device panel prepared in advance was bonded, liquid crystal was injected from the remaining part, and then an injection port was bonded and sealed to obtain a liquid crystal display device.

On the back side of this liquid crystal display device, as a blue light emitting diode, a sapphire substrate mainly made of gallium nitride / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.2) is used, and as a green light emitting diode, sapphire substrate / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.4) is used, and the red light emitting diode is GaAs substrate / n-GaAs
/ N-InGaAlP / undoped InGaAlP / p-InGaAlP / p-GaAs /
A large number of electrodes were repeatedly arranged in this order, and emitted light was guided to the display surface of the liquid crystal display element by the light guide plate. The obtained liquid crystal display device achieved 101% of NTSC color characteristics.

<Example 2> Using the same photosensitive coloring resin as in Example 1, a color filter was prepared under the following conditions.
First, a red photosensitive coloring composition was spin-coated on a substrate having a black matrix formed thereon and dried. 7
After prebaking at 0 ° C. for 20 minutes, 400 mJ / cm 2 exposure was performed using a mask having the same pixel size as one pixel of the liquid crystal display element. Develop with an aqueous solution of 2.5% sodium carbonate, wash with water,
Further, after washing with water and drying, the pattern was solidified by drying at 230 ° C. for 30 minutes. The film thickness after baking was 2.5 μm. Next, the green photosensitive coloring composition was spin-coated and dried. Thereafter, a green pattern having a film thickness of 2.5 μm was obtained by the same process as for red. Furthermore, the blue photosensitive coloring composition was spin-coated and dried. Then, a blue pattern having a film thickness of 2.5 μm was obtained by the same process as the previous color.

Using this color filter, ITO having a thickness of 140 nm was formed on the color filter and dried at 220 ° C. for 1 hour, and then an alignment film was applied to 50 nm and dried. A part of the TFT device panel prepared in advance was bonded, liquid crystal was injected from the remaining part, and then the injection port was bonded and sealed to obtain a liquid crystal display device.

On the back side of this liquid crystal display device, as a blue light emitting diode, a sapphire substrate mainly made of gallium nitride / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.2) is used, and as a green light emitting diode, sapphire substrate / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.4) is used, and the red light emitting diode is GaAs substrate / n-GaAs
/ N-InGaAlP / undoped InGaAlP / p-InGaAlP / p-GaAs /
A large number of electrodes were repeatedly arranged in this order, and emitted light was guided to the display surface of the liquid crystal display element by the light guide plate. The obtained liquid crystal display device achieved 107% of NTSC color characteristics.

<Example 3> (Preparation of photosensitive coloring composition) Acrylic resin (20 parts of methacrylic acid, 30 parts of butyl acrylate, 50 parts of butyl methacrylate) was dissolved in 300 parts of ethyl cellosolve and azobisisobutyl was added under a nitrogen atmosphere. 0.75 parts of nitrile was added and the acrylic resin obtained by the reaction at 70 ° C. for 5 hours was diluted with ethyl cellosolve so that the resin concentration became 20%. To 50 g of this diluted resin, 13 g of pigment, 0.6 g of a dispersant, and 36.4 g of cyclohexanone as a solvent were added and sufficiently kneaded with a three-roll to prepare a red colored resin (paste). Similarly, 11 g of the pigment, 1.0 g of the dispersant, and 38.0 g of cyclohexanone as a solvent were added to 50 g of the diluted resin, and the mixture was sufficiently kneaded with a three-roll mill to prepare a green colored resin (paste). Then, 9.5 g of a pigment, 1.0 g of a dispersant, and 39.5 g of cyclohexanone as a solvent were added to 50 g of the diluted resin, and the mixture was sufficiently kneaded with a three-roll to prepare a blue colored resin (paste).

The pigments and dispersants are shown below. [For red] 13 g of pigment Rubin TR (CI Pigment Red 264 manufactured by Ciba-Geigy).

[For green] A mixture of 6.5 g of pigment (CI Pigment Green 7 manufactured by Toyo Ink Mfg. Co., Ltd.) and 3.5 g of LY2311 (CI Pigment Yellow 13 manufactured by Toyo Ink Mfg. Co., Ltd.) Copper phthalocyanine derivative of dispersant CuPC [SO2 N (C18H3
7) 2] 2

[For blue] Pigment lionol blue ES (CI Pigment Blue 15: 6 manufactured by Toyo Ink) 10.0 g and Lionogen Violet HR (CI Pigment Violet 23 manufactured by Toyo Ink) 0.5 g Mixture with.

50 g of each colored resin, 4 g of dipentaerythritol acrylate and 2-methyl-1- (4-
(Methylthio) phenyl) -2-morpholinopropan-1-one 0.8 g, methoxystyryltriazine 0.
2 g, 3 g of the diluted resin previously synthesized, and 41 g of propylene glycol dimethyl acetate were added and well stirred to obtain a photosensitive coloring composition of each color.

(Production of Color Filter) First, a red photosensitive coloring composition was spin-coated on a substrate having a black matrix formed thereon and dried. After prebaking at 70 ° C. for 20 minutes, 400 mJ / cm 2 exposure was performed using a mask having the same pixel size as one pixel of the liquid crystal display element. It was developed with an aqueous solution of 2.5% sodium carbonate, washed with water, further washed with water, dried and then dried at 230 ° C. for 30 minutes to solidify the pattern. The film thickness after baking was 2.4 μm. Next, the green photosensitive coloring composition was spin-coated and dried. Thereafter, a green pattern having a film thickness of 2.4 μm was obtained by the same process as that for red. Furthermore, the blue photosensitive coloring composition was spin-coated and dried. Thereafter, a blue pattern having a film thickness of 2.4 μm was obtained by the same process as the previous color. The spectrum of the obtained color filter was measured.

Using this color filter, ITO having a thickness of 140 nm was formed on the color filter and dried at 220 ° C. for 1 hour, and then an alignment film was applied by 50 nm and dried. A display element was completed by partially adhering a TFT element prepared in advance, injecting liquid crystal from the remaining portion, and finally adhering injection. Then, the injection port was stuck and sealed to obtain a liquid crystal display device. On the back side of this liquid crystal display device, as a blue light emitting diode, a sapphire substrate mainly made of gallium nitride / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.2) is used, and as a green light emitting diode, sapphire substrate / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.4) is used, and the red light emitting diode is GaAs substrate / n-GaAs
/ N-InGaAlP / undoped InGaAlP / p-InGaAlP / p-GaAs /
A large number of electrodes were repeatedly arranged in this order, and emitted light was guided to the display surface of the liquid crystal display element by the light guide plate. The obtained liquid crystal display device achieved 104% of NTSC color characteristics.

<Example 4> Using the same photosensitive coloring resin as in Example 1, a color filter was prepared under the following conditions.
First, a red photosensitive coloring composition was spin-coated on a substrate having a black matrix formed thereon and dried. 7
After prebaking at 0 ° C. for 20 minutes, 400 mJ / cm 2 exposure was performed using a mask having the same pixel size as one pixel of the liquid crystal display element. Develop with an aqueous solution of 2.5% sodium carbonate, wash with water,
Further, after washing with water and drying, it was dried at 230 ° C. for 30 minutes to harden the pattern. The film thickness after baking was 2.5 μm. Next, the green photosensitive coloring composition was spin-coated and dried. Thereafter, a green pattern having a film thickness of 2.5 μm was obtained by the same process as for red. Furthermore, the blue photosensitive coloring composition was spin-coated and dried. Then, a blue pattern having a film thickness of 2.5 μm was obtained by the same process as the previous color. The spectrum of the obtained color filter was measured.

Using this color filter, ITO having a thickness of 140 nm was formed on the color filter and dried at 220 ° C. for 1 hour, and then an alignment film was applied at 50 nm and dried. A part of the TFT device panel prepared in advance was bonded, liquid crystal was injected from the remaining part, and then the injection port was bonded and sealed to obtain a liquid crystal display device. On the back side of this liquid crystal display device, as a blue light emitting diode, a sapphire substrate mainly made of gallium nitride / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.2) is used, and as a green light emitting diode, sapphire substrate / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.4) is used, and the red light emitting diode is GaAs substrate / n-GaAs
/ N-InGaAlP / undoped InGaAlP / p-InGaAlP / p-GaAs /
A large number of electrodes were repeatedly arranged in this order, and emitted light was guided to the display surface of the liquid crystal display element by the light guide plate. The obtained liquid crystal display device achieved 103% of NTSC color characteristics.

Example 5 (Preparation of Photosensitive Coloring Composition) Acrylic resin (20 parts of methacrylic acid, 30 parts of butyl acrylate, 50 parts of butyl methacrylate) was dissolved in 300 parts of eryl cellosolve, and azobisiso was prepared under a nitrogen atmosphere. 0.75 parts of butyl nitrile was added, and the acrylic resin obtained by the reaction at 70 ° C. for 5 hours was diluted with ethyl cellosolve so that the resin concentration became 20%. To 50 g of this diluted resin, 13 g of pigment, 0.6 g of a dispersant, and 36.4 g of cyclohexanone as a solvent were added and sufficiently kneaded with a three-roll to prepare a red colored resin (paste). Similarly, 11 g of the pigment, 1.0 g of the dispersant, and 38.0 g of cyclohexanone as a solvent were added to 50 g of the diluted resin, and the mixture was sufficiently kneaded with a three-roll mill to prepare a green colored resin (paste). Then, 9.5 g of a pigment, 1.0 g of a dispersant, and 39.5 g of cyclohexanone as a solvent were added to 50 g of the diluted resin, and the mixture was sufficiently kneaded with a three-roll to prepare a blue colored resin (paste).

The pigments and dispersants are shown below. [For red] 13 g of pigment Rubin TR (CI Pigment Red 264 manufactured by Ciba-Geigy).

[For green] Pigment (CI Pigment Green 7 manufactured by Toyo Ink)
A mixture of 6.5 g and 3.5 g of LY2311 (CI Pigment Yellow 13 manufactured by Toyo Ink). Copper phthalocyanine derivative of dispersant CuPC [SO2 N (C18H3
7) 2] 2

[For blue] Pigment lionol blue ES (CI Pigment Blue 15: 6 manufactured by Toyo Ink) 10.0 g and Lionogen violet HR (CI Pigment Violet 23 manufactured by Toyo Ink) 0.5 g Mixture with.

50 g of each colored resin, 4 g of dipentaerythritol acrylate and 2-methyl-1- (4-
(Methylthio) phenyl) -2-morpholinopropan-1-one 0.8 g, methoxystyryltriazine 0.
2 g, 3 g of the diluted resin previously synthesized, and 41 g of propylene glycol dimethyl acetate were added and well stirred to obtain a photosensitive coloring composition of each color.

(Production of Color Filter) First, a red photosensitive coloring composition was spin-coated on a substrate having a black matrix formed thereon and dried. After prebaking at 70 ° C. for 20 minutes, 400 mJ / cm 2 exposure was performed using a mask having the same pixel size as one pixel of the liquid crystal display element. It was developed with an aqueous solution of 2.5% sodium carbonate, washed with water, further washed with water, dried and then dried at 230 ° C. for 30 minutes to solidify the pattern. The film thickness after baking was 3.0 μm. Next, the green photosensitive coloring composition was spin-coated and dried. Thereafter, a green pattern having a film thickness of 3.0 μm was obtained by the same process as for red. Furthermore, the blue photosensitive coloring composition was spin-coated and dried. Then, a blue pattern having a film thickness of 3.0 μm was obtained by the same process as the previous color. The spectrum of the obtained color filter was measured.

Using this color filter, 140 nm ITO was formed on the color filter and dried at 220 ° C. for 1 hour, and then an alignment film was applied by 50 nm and dried. A part of the TFT device prepared in advance was bonded, liquid crystal was injected from the remaining part, and then the injection port was bonded and sealed to obtain a liquid crystal display device. On the back side of this liquid crystal display device, as a blue light emitting diode, a sapphire substrate mainly made of gallium nitride / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.2) is used, and as a green light emitting diode, sapphire substrate / n-GaN / n-Al 0.15Ga 0.85N / InxGa1-x
N / p-Al 0.15Ga 0.85N / p-GaN / electrode, (x = 0.4) is used, and the red light emitting diode is GaAs substrate / n-GaAs
/ N-InGaAlP / undoped InGaAlP / p-InGaAlP / p-GaAs /
A large number of electrodes were repeatedly arranged in this order, and emitted light was guided to the display surface of the liquid crystal display element by the light guide plate. The obtained liquid crystal display device achieved 108% of NTSC color characteristics.

[0063]

According to the present invention, the color filter red (R),
By increasing the saturation and transmittance of the three primary colors of green (G) and blue (B) and using a light emitting diode having a sharp emission spectrum characteristic of red, green, and blue as a backlight for a liquid crystal display device, It is possible to obtain a color filter and a liquid crystal display device having a color characteristic equal to or higher than that of the color CRT. By using a three-color backlight of such a light emitting diode,
It is possible to enjoy a liquid crystal display of a color display that is more vivid and has a wider color reproduction range, and it is possible to give the liquid crystal display device a wider range of applications such as a color television receiver for broadcasting and a monitor.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an explanatory cross-sectional view of a main part showing an embodiment of the liquid crystal display device of the present invention.

FIG. 3 is an explanatory diagram showing an example of emission spectral characteristics of a three-wavelength fluorescent tube.

FIG. 4 is an explanatory diagram showing an example of red, green, and blue emission spectral characteristics of a light emitting diode.

[Explanation of symbols] 1 Liquid crystal display 2 Light emitting diode light source 3 concave reflector 4 LCD display panel 5 Light guide plate 6 reflector

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H048 BA02 BA45 BA47 BB02 BB10                       BB42                 2H091 FA02Y FA23X FA23Z FA35Y                       FA45X FA45Z FB01 FB04                       FB11 FC01 FC10 FC21 FC22                       FC24 GA01 GA02 GA03 GA06                       GA13 KA10 LA15 LA16 LA18                       LA30

Claims (2)

[Claims] 1. A color filter for a color liquid crystal display device using a blue-green-red light-emitting diode as a color light source of a backlight, wherein the peak wavelength of the blue-green-red light-emitting diode is:
It is in the range of 430 to 480 nm for blue and 520 to 5 for green.
It is in the range of 70 nm, in the range of 620 to 660 nm for red, the half-value wavelength width of which is ± 15 nm from the peak wavelength for blue and ± 20 for green.
It is a backlight having a light emission characteristic of a width of nm and a width of plus or minus 15 nm in red, and the spectral transmittance of the color filter at the peak wavelength of blue-green-red of the light emitting diode is 80% or more for blue-red-green. A color filter for a liquid crystal display device characterized by: 2. A color liquid crystal display device using a blue-green-red light-emitting diode as a color light source of a backlight and a blue-green-red color filter, wherein the light-emitting diode has a blue-green-red peak wavelength of 430. ~ 480 nm, green 520-570 nm, red 620-660
and a half-value wavelength width of blue is ± 15 nm from the peak wavelength, green is within ± 20 nm, and red is within ± 15 nm. A liquid crystal display device characterized in that the spectral transmittance of a color filter at a peak wavelength of blue-green-red of a light emitting diode is 80% or more for blue-red-green.