JP2003005361A - Red resist composition using high transmittance red dye and color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a color filter having a higher luminance (white-Y value) than a conventional color filter by using a dye, to provide a red colored resist for a color filter having a higher solvent resistance and durability than a color filter using a conventional water-soluble dye and to provide a color filter using the colored resist. SOLUTION: When the red resist composition is formed as a coating film, a measured value in the CIE standard color system shows a luminance of a Y value of >=28 at 0.5950 of the x-coordinate axis in F10 light source colorimetry. The red resist composition contains a solvent-soluble red dye of formula (1), a binder resin, a photopolymerizable monomer, a photopolymerization initiator and a solvent. A color filter is produced using the red resist composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coloring composition for producing a color filter (hereinafter simply referred to as a coloring resist) used in the fields of electronic displays, image sensors for color display, etc., which uses a red dye as a coloring material. The present invention relates to a highly transparent colored resist used and a color filter using the colored resist. In particular, the present invention is a colored resist for producing a high-brightness type color filter most suitable for a portable liquid crystal display, which has a high transmittance of a colored resist using a red dye as a coloring material, and a color filter using the colored resist. Regarding

[0002]

2. Description of the Related Art In a liquid crystal driven display, a color filter is arranged in a liquid crystal cell structure in order to display a color image. The color filter is generally composed of (1) a light-shielding black portion (Bk), (2) a color display Red (R), and G on the glass surface.
It is composed of four member layers of a reen (G) and a blue (B) color matrix, (3) a transparent film holding the color matrix, and a transparent electrode film for driving a liquid crystal. In order to form a color matrix layer of these layers in a color filter, various methods, for example, a dyeing method using a dye and various pigment dispersion methods using a pigment have been conventionally proposed.

Conventionally, the production of a color filter for a liquid crystal display device by a dyeing method using a dye has been carried out as follows, for example, as shown in JP-A-1-198721. Water-soluble photosensitive dyeing base material such as gelatin and casein is coated on the entire surface of a substrate (glass) on which a light non-transmissive part (black matrix) having regular openings is formed, and then for exposure of a predetermined pattern The mask is used to irradiate ultraviolet rays to cause a cross-linking polymerization reaction of the photosensitive dyeing base material having a predetermined opening. Then, after developing with a developing solution to obtain an island pattern, for example, the island pattern at a predetermined location is dyed with a dyeing solution in which a green (G) dye is dissolved, and a green (G) color filter is obtained. obtain. Then, for the other colors, the island-shaped patterns at predetermined locations are sequentially dyed by the same procedure as above to form a pattern of three primary colors of light of green (G), red (R), and blue (B) To obtain a color filter for liquid crystal display. The color filter obtained by the dyeing method has a drawback that it is inferior in solvent resistance and durability because the water-soluble photosensitive dyeing base material on the substrate is dyed with an aqueous dye solution.

On the other hand, a method for producing a color filter for liquid crystal display by a pigment dispersion method using a colored resist composed of a pigment, a photosensitive resin and a solvent is performed, for example, as follows. That is, a photosensitive liquid in which a colorant such as an organic pigment or an inorganic pigment is dispersed in a transparent photosensitive resin is applied on a transparent glass substrate to form a photosensitive resin layer. Next, a mask having an opening pattern of a predetermined shape is placed on this photosensitive resin layer, and exposure and development are performed to form a first colored layer. Similarly, the second colored layer and the third colored layer are formed to obtain a color filter including the R, G, and B colored layers. Since the color filter obtained by the pigment dispersion method is superior in solvent resistance and durability as compared with that obtained by the dyeing method, the pigment dispersion method is currently the mainstream in the production of color filters.

[0005]

In recent years, mobile devices such as mobile phones and portable terminals have been remarkably developed, and there is a demand for an energy-saving type that is compact, has high brightness and good visibility, and does not require long-time charging. There is.

Currently, color filters for liquid crystal displays provided in these mobile devices are mainly
It is obtained by the pigment dispersion method. However,
Even if a pigment having a particle size as small as possible is used in order to increase the permeation of the color filter using the pigment, aggregation easily occurs, and thus it is difficult to perform stable fine particle dispersion that exhibits sufficient permeation. Therefore, in order to improve the visibility of a liquid crystal display using a color filter obtained by the pigment dispersion method, it is generally used in combination with a high-brightness backlight. It requires a large amount of power and does not save energy.

On the other hand, a color filter obtained by a conventional dyeing method has high permeability in a solution state in which a dye is dissolved, but when a colored coating film is formed, crystals are formed on the surface of the film and the same as in the solution state. It is difficult to reproduce the transmission. Therefore, also in a liquid crystal display using a color filter by a dyeing method, it is being combined with a backlight having a similar high brightness.

Therefore, the present invention realizes a color filter having a higher brightness (White-Y value) than a conventional color filter by using a dye, and is more resistant to solvent than a color filter using a conventional water-soluble dye. It is an object of the present invention to provide a red colored resist for a color filter having excellent properties and durability, and to provide a color filter using the colored resist.

[0009]

When the red resist composition of the present invention for solving the above-mentioned problems is formed into a coating film, the measured value in the color system standardized by the CIE committee is F10. A red resist composition exhibiting a luminance of Y value 28 or more at an x coordinate of 0.5950 measured by a light source, and having the following formula (1):

[0010]

[Chemical 2]

A red resist composition for a color filter containing a solvent-soluble red dye, a binder resin, a photopolymerizable monomer, a photopolymerization initiator and a solvent represented by:

In the color system standardized by the CIE committee, trichromatic stimulus values (X, Y, Z) and trichromatic coefficients (x, y,
It is generally used to represent the color with a colorimetric value represented by (Y, x, y) selected from z). According to the JIS standard in Japan, it is defined as z-8701,
It is represented by (X, Y, Z) and is called an "XYZ color system", which has exactly the same content as the colorimetric value (Y, x, y). Y (large wai) is basically a parameter representing brightness, and x and y are parameters representing the color quality (hue and saturation) of the color, that is, chromaticity coordinates.

The solvent contained in the red resist composition of the present invention contains the solvent-soluble red dye represented by the above formula (1), and the solvent-soluble red dye is contained in the solvent, for example, cyclohexanone or propylene glycol. The solubility in monomethyl ether acetate or the like is 2% by weight or more.

The red resist composition of the present invention has a Y value of 28 or more at an x coordinate of 0.5950 by F10 light source colorimetry when formed into a coating film, so that a highly transparent red coating film can be formed. A color filter formed by combining a red pattern formed by the red resist composition of the present invention with a green pattern containing a dye or pigment of other three primary colors and a blue pattern is the center of gravity of those colors (Y, x, y). The white brightness of the white-point (White-Y) is high.

Red Resist Composition The solvent (eg, cyclohexanone solvent) used in the red resist composition of the present invention is a solvent capable of dissolving 2% by weight or more of the solvent-soluble red dye represented by the above formula (1). Is preferred. When the solubility of the dye represented by the formula (1) in a solvent is less than 2% by weight, F when the coating film is formed,
With 10 light source colorimetry, the Y value at the x-coordinate of 0.5950 does not reach a luminance of 28 or more, and there is a possibility that a highly transmissive red may not be obtained, which is not preferable.

The above solvent-soluble red dye has a transmittance of 91% or more for light of 610 nm, 95% or more for light of 620 nm, and transmittance of 500 nm for light of F10 light source color when formed into a coating film. It is desirable that the rate is 10% or less. The compound represented by the formula (1) is, for example, a compound obtained by diazotizing 4-amino-N-benzoyl-N-ethyl-m-benzotoluidide and coupling with NW (neville windsor) acid, After neutralization, it can be obtained by a method of salting out with sodium chloride, further membrane treatment, and purification.

The red resist composition of the present invention contains a solvent-soluble red dye, a binder resin, a photopolymerizable monomer, a photopolymerization initiator and a solvent.

The binder resin that can be used in the red resist composition of the present invention is a linear organic polymer which is compatible with photopolymerizable monomers and which is soluble in a solvent and can be developed. Can be preferably used. Specifically, use methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, partially esterified maleic acid copolymer, polyimide resin, etc. However, it is preferable to use an acrylic resin because of its transparency, processability, and heat resistance.

The photopolymerizable monomer usable in the red resist composition of the present invention has at least one addition-polymerizable ethylenically unsaturated group and has a boiling point of 10 at room temperature.
It is preferably 0 ° C. or higher. Specifically, a monofunctional acrylate or methacrylic acid, a polyfunctional alcohol to which ethylene oxide or propylene oxide is added and then methacrylic acid, and the like can be used.
Furthermore, polyester acrylates, polyfunctional acrylates such as epoxy acrylates which are a reaction product of epoxy resin and methacrylic acid and methacrylates, photocurable monomers and oligomers, butyral resins, styrene-maleic acid copolymers, Polyvinyl acetate, phenol resin, etc. can be used, but because of their reactivity,
Preference is given to using polyfunctional acrylate monomers.

The photopolymerization initiator that can be used in the red resist composition of the present invention includes vicinal polyketoaldonyl compounds, α-carbonyl compounds, asioin ethers, divergent quinone compounds, triallyl imidazole dimers / p-.
A combination of aminophenyl ketones, trioxadiazole compounds and the like can be mentioned, preferably 2-benzyl-2-
Examples thereof include dimethylamino-1- (4-morpholinophenyl) butanone (Irgacure 369: trade name, manufactured by Ciba Specialty Chemicals). Among them, the bisimidazole photopolymerization initiator is preferable because of its high sensitivity.

Solvents that can be used in the red resist composition of the present invention include glycol ether type, its acetate type,
Acetate-based and ketone-based solvents can be used as appropriate. In particular, cyclohexanone and propylene glycol monomethyl ether acetate can be preferably used.

Dye-based red resist of the present invention and conventional pigment
Comparison of Coating Films Using Red-Based Resists FIG. 1 shows F1 of coating films prepared in the following production examples using the red resist composition of the present invention containing a solvent-soluble red dye.
Spectral distribution curve (solid line) of transmittance (%) at 0 light source color measurement
And a spectral distribution curve (dotted line) of a coating film prepared in the following production example using a conventional red pigment dispersion. Further, FIG. 2 shows a spectral distribution curve of the F10 light source. The peak in the red portion of the spectral distribution curve of the F10 light source in FIG. 2 exists at 610 nm. Here, the transmittance of the red coating film using the red dye-containing red resist composition in FIG. 1 for light of 610 nm is 94.5%, and the transmittance for light of 620 nm is 96.5%. On the other hand, in FIG. 1, the transmittance of the red coating film using the conventional red pigment dispersion liquid for light of 610 nm is 90.0%, and the transmittance for light of 620 nm is 93.0%. .

As can be seen from FIG. 1, at the peak wavelength 610 nm of the transmittance of the red portion of the F10 light source,
The red coating film of the red dye-containing red resist composition of the present invention has a higher transmittance than the coating film of the conventional red pigment dispersion liquid, and the shoulder peak at the foot of the red portion of the spectral distribution curve of the F10 light source. Even at the wavelength of 620 nm, the red coating film of the red dye-containing red resist composition of the present invention has a higher transmittance than the coating film of the conventional red pigment dispersion liquid. Further, in both spectral distribution curves in FIG. 1, the red coating film of the red dye-containing red resist of the present invention is steeper than the coating film of the conventional red pigment dispersion liquid at the rising edge of the curve near red. In addition, since the transmittance is high in the entire red wavelength range, vivid and bright color reproduction is possible.

The coating film used for the data of the red dye-containing red coating film shown by the solid line in the graph of FIG. 1 was manufactured as follows. That is, 6.7 parts by weight of an acrylic copolymer composition, 1.3 parts by weight of dipentaerythritol pentaacrylate, 0.4 parts by weight of a morpholinophenyl photopolymerization initiator, 116.0 parts by weight of cyclohexanone, and the above formula (1).
2.0 parts by weight of the compound represented by are thoroughly stirred, and the liquid is filtered through a 1.5 μm filter to remove dust.
The filtrate was spin-coated on a non-alkali glass having a thickness of 0.7 mm by a spin coater, and then dried on a hot plate heated to 90 ° C. for 3 minutes, and then exposed on the front surface at an exposure amount of 100 mJ / cm ² . Then, it was post-cured in an oven heated to 180 ° C. for 30 minutes to form a red coating film having a film thickness of about 1.5 μm.

The coating used for the data of the coating containing red pigment shown by the dotted line in the graph of FIG. 1 was manufactured as follows. That is, instead of the solvent cyclohexanone described above, propylene glycol monomethyl ether acetate,
Instead of the compound represented by the formula (1) of the coloring component,
The content (CI Pigment Red 254)
Dispersant with a pigment weight ratio of 0.4 (Azisper PB-82
1, manufactured by Ajinomoto Co., Inc.) and propylene glycol monomethyl ether acetate were used to form a red coating film having a thickness of about 1.5 μm using a pigment dispersion liquid dispersed in a bead mill or the like.

Manufacturing Example of Color Filter For example, a manufacturing example of the color filter of the present invention having a black matrix will be described with reference to FIG. In FIG. 3, (1) to (7) show the order of steps. A black matrix-forming resist composition 2 is coated on the entire surface of a glass substrate 1 (1), exposed through a photomask (not shown) for forming a black matrix (2), and developed to develop black. A matrix pattern 3 is formed (3). Then, a red resist composition 4 of the present invention, which is one of the three primary colors of light, is applied to the entire surface to form a coating film (4), and a photomask for a red pattern having openings at predetermined positions (not shown). The red pattern 5 is exposed by exposing the pattern through (5) and developing it.
(R) is formed (6). Then, one of the other three primary colors, for example, a green resist composition is applied to the entire surface to form a coating film, and the pattern is exposed through a photomask for a green pattern having openings at predetermined positions, The green pattern 6 (G) is formed by developing this. Finally, in the same manner, a blue color pattern 7 (B) is formed using the remaining one of the three primary colors, for example, a blue resist composition, thereby obtaining a color filter having a pattern of red, green, and blue (7). ). The blue resist composition may be either a blue pigment or one containing a blue dye, and the green resist composition may be any one containing a green pigment or a green dye. Then, if necessary, a transparent topcoat layer may be provided on the surface and an ITO film for a transparent electrode may be formed thereon in order to protect and flatten the pixel portion.

[0027]

EXAMPLES Preparation of Red Resist Composition A compound having a high solubility in a solvent and represented by the above formula (1) is used as a highly transparent dye, and the red dye described above with reference to the graph of FIG. 1 is contained. A red resist solution was prepared by exactly the same method as the method for producing a film prepared using the red resist composition.

Formation of Red Coating Film The obtained red resist solution was applied by spin coating, dried and exposed with a light amount of 100 mJ / cm ² , and then the coating film was completely cured and the remaining solvent was volatilized to 180. Post-cure at 30 ° C for 30 minutes to obtain a thickness of about 1.
A 5 μm red coating film was formed.

For comparison, a general-purpose red pigment (C.I.
gment Red 254) dispersion was prepared, and a red coating film having a film thickness of about 1.5 μm was prepared under the same conditions.

Spectral transmittance of each coating film was measured, and in order to compare the two coating films, the chromaticity x was kept constant (that is, red was kept constant) and color correction was performed by simulation. The chromaticity (x, y) and the luminance (Y) are shown in Table 1 below.

[0031]

[Table 1]

According to Table 1, the red coating film prepared by using the red resist composition prepared by dissolving the solvent-soluble red dye has a brightness of 2. than the one prepared by using the pigment-dispersed red resist composition. 468 also rises, showing much higher brightness than that of the pigment dispersion system, that is, it can be seen that the red coating film of the present invention has high transmission.

Measurement of White Brightness (White-Y) Using a red coating film containing the highly transparent red dye obtained in the above step, a green coating film formed by using a general-purpose green pigment, and a general-purpose blue pigment. The R, G, and B color reproduction areas (three primary color triangles) are obtained for the blue coating film formed by the above method, and the white luminance (White-point) of the center of gravity (White-point) is obtained.
Y) was calculated. The results are shown in Table 2 below. Also,
The red pigment (C.I.P.
Pigment Red 254), a blue pigment (CI Pigment Blue 15), a toning green pigment (CI Pigment Green 36 +)
C. I. Pigment Yellow 138) was similarly used to form a blue coating film and a green coating film, respectively. The three primary color triangles are obtained for the red coating film, the green coating film, and the blue coating film, and their center of gravity (White-poi) is calculated.
nt) white brightness (White-Y) was calculated, and the value is shown in Table 2 below.

[0034]

[Table 2]

As shown in Table 2, the use of a highly transparent solvent-soluble red dye is more advantageous than the use of a general-purpose red pigment.
It can be seen that the white brightness is high. The NTSC ratio is 4
Unified to 5%. By the way, what is the NTSC ratio?
R, G, B set by Television System Cmmmittee
Is the area ratio to the color reproduction area formed from the chromaticity points of the three primary colors.

[0036]

EFFECTS OF THE INVENTION By using a red resist composition containing a highly transparent solvent-soluble red dye, a bright (high Y
Value), so that when this red coating is applied to the red pattern of the color filter and combined with the green and blue patterns, their color (Y,
White point, which is the center of gravity of (x, y) -white brightness of point (W
It is possible to realize a color filter having a high value of hite-Y). Moreover, it is possible to obtain a color filter which is more excellent in solvent resistance and durability than a color filter using a conventional water-soluble dye.

[Brief description of drawings]

FIG. 1 is a spectral distribution curve (solid line) of transmittance (%) in F10 light source color measurement of a coating film prepared using a red resist composition of the present invention containing a highly transparent solvent-soluble red dye, and And a spectral distribution curve (dotted line) of a coating film prepared by using the red pigment dispersion liquid.

FIG. 2 shows a spectral distribution curve of an F10 light source.

FIG. 3 shows an example of manufacturing the color filter of the present invention.

[Explanation of symbols]

1 glass substrate 2 Black matrix forming resist composition 3 black matrix pattern 4 Red resist composition 5 red pattern 6 green pattern 7 blue pattern

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayoshi Kojima             3-43-19 Shimo, Kita-ku, Tokyo Nippon Kayaku             Within the corporation (72) Inventor Noriko Kajiura             3-43-19 Shimo, Kita-ku, Tokyo Nippon Kayaku             Within the corporation F-term (reference) 2H025 AA00 AA06 AB13 AC01 AD01                       BC13 BC42 CC13                 2H042 AA09 AA15 AA26                 2H048 BA11 BA45 BA47 BA48 BB01                       BB02 BB44

Claims (5)

[Claims] 1. A red resist composition which, when formed into a coating film, has a measured value in a color system standardized by the CIE committee and has a Y value of 28 or more at an x-coordinate of 0.5950 in an F10 light source colorimetry. And the following formula (1) A red resist composition for a color filter containing a solvent-soluble red dye, a binder resin, a photopolymerizable monomer, a photopolymerization initiator and a solvent represented by: 2. The red resist composition for a color filter according to claim 1, wherein the solvent is a solvent capable of dissolving 2% by weight or more of the solvent-soluble red dye represented by formula (1) according to claim 1. 3. A coating film having a F10 light source colorimetry of 61
The red resist composition for a color filter according to claim 1 or 2, wherein the transmittance for light of 0 nm is 91% or more, the transmittance for light of 620 nm is 95% or more, and the transmittance for light of 500 nm is 10% or less. 4. A color filter formed using the red resist composition according to claim 1. 5. A color filter formed by combining a red pattern formed by using the red resist composition according to claim 1, 2 or 3 with a green pattern and a blue pattern.