JP2002311225A - Color filter and method for manufacturing the same, liquid crystal element using the color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a bright defect and chrominance non-uniformity caused by concentration distribution inside each pixel in a color filter manufactured with an inkjet method. SOLUTION: Ink quantity discharged from an inkjet head is adjusted by controlling a landing dot diameter of the ink. Therefore, in each of the pixel an area of a region with ink concentration thinner than an average concentration value inside the pixel by >=15% is kept <=20% of the area of the pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter applicable to a color liquid crystal display used for a color television, a personal computer, an automobile navigation system, a small television, and the like.
The present invention relates to a method for manufacturing a color filter for forming a colored portion by applying ink by an ink jet method. Further, the present invention relates to a color filter manufactured by the manufacturing method and a liquid crystal device using the color filter.

[0002]

2. Description of the Related Art In recent years, the development of personal computers,
In particular, with the development of portable personal computers, the demand for liquid crystal displays, especially color liquid crystal displays, tends to increase. However, cost reduction is required for further widespread use, and in particular, there is an increasing demand for cost reduction of color filters having a high specific gravity in terms of cost.

Conventionally, various methods have been tried to satisfy the above requirements while satisfying the required characteristics of the color filter, but no method has yet been established which satisfies all the required characteristics. Hereinafter, each method will be described.

[0004] The first method most frequently used is a dyeing method. In the dyeing method, first, a layer of a water-soluble polymer material, which is a material for dyeing, is formed on a glass substrate, and this is patterned into a desired shape by a photolithography process, and the obtained pattern is immersed in a dyeing bath. To obtain a colored pattern. By repeating this three times, R
(Red), G (green), and B (blue) color filter layers are formed.

[0005] A second method is a pigment dispersion method, which has recently been replaced by a dyeing method. In this method, first, a photosensitive resin layer in which a pigment is dispersed is formed on a substrate, and a monochromatic pattern is obtained by patterning the photosensitive resin layer. This process is further repeated three times to form R, G, and B color filter layers.

A third method is an electrodeposition method. In this method, a transparent electrode is first patterned on a substrate, and a pigment,
The first color is electrodeposited by dipping in an electrodeposition coating solution containing a resin, an electrolytic solution or the like. This process is repeated three times to form R, G, and B color filter layers, and finally baked.

As a fourth method, a pigment is dispersed in a thermosetting resin, and printing is repeated three times so that R, G,
After separately applying B, the resin is thermally cured to form a colored layer. In any method, a protective layer is generally formed on the colored layer.

What is common to the above-mentioned conventional manufacturing methods is that
The same process needs to be repeated three times in order to color the three colors of R, G, and B, which increases the cost. Also,
There is a problem that the yield decreases as the number of processes increases. Further, in the electrodeposition method, since the pattern shape that can be formed is limited, it is difficult to apply the current technology to an active matrix type using a TFT (thin film transistor), that is, a so-called TFT type. Further, the printing method is not suitable for forming a fine pitch pattern because of poor resolution.

[0009]

In order to compensate for the drawbacks of the above-mentioned conventional production methods, Japanese Patent Application Laid-Open Nos. 59-75205 and 63-235901 disclose a method for producing a color filter using an ink jet method. JP-A 1-21
No. 7320, Japanese Patent Application Laid-Open No. 4-123005, and the like have been proposed. These are different from the above-mentioned conventional method, in which inks of each color of R, G, B are applied to a predetermined position on a transparent substrate from an inkjet head, and the ink is dried on the substrate to form a colored portion. It is. According to this method, the colored portions of R, G, and B can be formed at once, and the amount of ink used is not wasted. The effect can be obtained.

[0010] However, when the colored portion is formed by the ink jet method, it is difficult for the ink dots discharged from the ink jet head and landed on the substrate to spread uniformly in the pixel. For this reason, color unevenness occurs in a portion where the density distribution is not uniform in the pixel, and a white spot phenomenon occurs particularly in a portion where the density distribution is biased, thereby deteriorating the display quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal element which is excellent in color display characteristics by using a color filter manufactured by an ink-jet method, in which color unevenness and white spots are reduced.

[0012]

According to the present invention, there is provided a color filter having, as pixels, a light-shielding portion and a colored portion located at an opening of the light-shielding portion on a transparent substrate. An object of the present invention is to provide a color filter wherein a region having a density of 15% or more with respect to a density average value is 20% or less of the area of the pixel.

According to the present invention, as a method of manufacturing the color filter of the present invention, first, a light-shielding portion having an opening corresponding to a pixel is formed on a transparent substrate, and light irradiation or light irradiation and heat treatment are performed. Forming a resin composition layer that reduces or increases the ink absorbency by applying light irradiation or light irradiation and heat treatment to a predetermined region of the resin composition layer to form at least the light-absorbing colored portion having a high ink absorbency. In the opening, a non-colored portion having a lower ink absorbency than the colored portion is formed on at least a part of the light-shielding portion, and the ink is applied to the colored portion while controlling the dot diameter by an ink jet method. Secondly, a method for producing a color filter, characterized in that it is applied and colored, and the entire resin composition layer is cured by light irradiation or heat treatment. Forming a light-shielding portion having an ink that is cured by applying energy to the opening of the light-shielding portion while controlling the landing dot diameter by an inkjet method, and curing the ink by applying energy. It is intended to provide a manufacturing method.

Further, the present invention provides a liquid crystal element in which liquid crystal is sandwiched between a pair of substrates, wherein one of the substrates is formed using the color filter of the present invention. Things.

[0015]

FIG. 1 shows a first method of manufacturing a color filter according to the present invention, which is a so-called negative resin composition in which the ink absorbency is reduced (or eliminated) by light irradiation or light irradiation and heat treatment. FIG. 4 is a process chart in the case of using an object.
Hereinafter, each step will be described. In addition, (a) of FIG.
(F) is a schematic cross-sectional view corresponding to each of the following steps (a) to (f).

Step (a) A black matrix 2 is formed on a substrate 1 as a light shielding portion. Although a glass substrate is generally used as the substrate 1,
It is not limited to a glass substrate as long as it has necessary characteristics such as transparency and mechanical strength as a color filter.

The black matrix 2 is formed by forming a metal thin film of chromium or the like on the substrate 1 by a film forming method such as sputtering or vacuum evaporation and patterning an opening or the like by a photolithography process. And the like formed by the above method can be used.

Step (b) On the substrate 1, a resin composition which is cured by light irradiation or light irradiation and heat treatment to reduce the ink absorbability of the light irradiated portion is applied, and if necessary, prebaked to obtain a resin. A composition layer 3 is formed. As a base resin of such a resin composition, an acrylic resin, an epoxy resin, an amide resin, or the like is used, but the resin is not particularly limited thereto.
In these resins, a photoinitiator (crosslinking agent) can be used to promote a crosslinking reaction by light or a combination of light and heat. As the photoinitiator, a dichromate, a bis azide compound, a radical initiator, a cationic initiator, an anionic initiator and the like can be used. Further, these photoinitiators can be used as a mixture or in combination with another sensitizer. Furthermore, a photoacid generator such as an onium salt can be used in combination with a crosslinking agent. still,
Heat treatment may be performed after light irradiation in order to further promote the crosslinking reaction.

The resin composition layer 3 is formed by spin coating, roll coating, bar coating, spray coating,
A coating method such as dip coating can be used, and is not particularly limited.

Step (c) Using the photomask 4, pattern exposure is performed on the resin composition layer in a region shielded by the black matrix 2, whereby the resin composition layer is cured to reduce the ink absorbency, and the uncolored portion 5 is formed.
To form The area that has not been exposed has high ink absorbency and becomes the colored portion 6. Since the non-colored portion 5 having low ink absorption is interposed between the adjacent colored portions 6, the non-colored portion 5
This prevents color mixing between adjacent colored portions. The photomask 4 used here has an opening for curing the light-shielding portion of the black matrix 2, but a large amount of ink is applied to prevent color omission at a portion in contact with the black matrix 2. Considering that it is necessary to use a mask, it is preferable to use a mask having an opening narrower than the light blocking width of the black matrix 2.

Step (d) R, G, B are applied to the portion 6 to be colored by the ink jet head 7.
Are applied according to a predetermined coloring pattern. At this time, as will be described later, the dot diameter of the ink landing is controlled.

The ink 8 used for coloring includes a pigment-based ink,
It is possible to use both a pigment system and a liquid ink or a solid ink. However, when using an aqueous ink, the resin composition layer 3 is formed of a highly water-absorbing resin composition. Is preferred. In addition, the ink is not limited to a liquid at room temperature, but is an ink that solidifies at room temperature or lower, and softens at room temperature, or is a liquid, or the ink itself is heated to 30 ° C. to 70 ° C. in a normal inkjet method. Since the viscosity of the ink is controlled within a stable range by adjusting the temperature within the range, a liquid in which the ink is in a liquid state when the ink is ejected is suitably used.

Further, as an ink jet system, a bubble jet (registered trademark) type using an electrothermal converter or a piezo jet type using a piezoelectric element can be used as an energy generating element. Can be set arbitrarily.

Step (e) After the ink is dried as required, the entire surface of the substrate is irradiated with light to cure the colored portion 6 to which the ink has been applied, thereby forming a colored portion 9. Heat treatment may be performed instead of light irradiation.

Step (f) If necessary, a protective layer 10 is formed. As the protective layer 10, a resin layer of a photo-curing type, a thermo-setting type or a combination of light and heat, or an inorganic film formed by vapor deposition, sputtering, or the like can be used, and has transparency when used as a color filter. Any material can be used as long as it can withstand the subsequent ITO film forming process, alignment film forming process, and the like.

Further, as the resin composition forming the resin composition layer 3, a positive resin composition whose ink absorbency increases (or develops) by light irradiation or light irradiation and heat treatment can be used. As such a resin composition,
Specifically, a system utilizing a reaction by chemical amplification is preferable. As the base resin, those obtained by esterifying hydroxyl groups of cellulose derivatives such as hydroxypropylcellulose and hydroxyethylcellulose, or blocking them with acetyl groups (eg, acetic acid) Cellulose-based compounds, etc.); High-molecular-weight alcohols such as polyvinyl alcohol, and derivatives thereof, in which hydroxyl groups are esterified or blocked with acetyl groups (eg, polyvinyl acetate-based compounds, etc.); Novolaks, such as cresol novolak Resins, polyparahydroxystyrene and derivatives thereof in which hydroxyl groups are blocked with, for example, a trimethylsilyl group are used, but the present invention is not limited thereto.

In the present invention, in order to cause a substantial difference in ink absorptivity due to exposure, the conversion ratio of a functional group that can be converted to a hydrophilic group into a hydrophilic group is generally 30% or more. Is preferred. As a method for quantifying the hydrophilic group in this case, spectrum analysis such as IR and NMR is effective.

As the photoinitiator, an onium salt such as triphenylsulfoniumhexanefluoroantimonate, a halogenated organic compound such as trichloromethyltriazine, or naphthoquinonediazide or a derivative thereof is preferably used, but is not limited thereto. Instead, any material may be used as long as it has a composition that results in an increase in the ink absorbency of the light-irradiated portion due to light irradiation or light irradiation and heat treatment.

When such a resin composition is used, a region other than a region shielded by the black matrix is exposed by using the black matrix formed on the transparent substrate as a mask and exposing from the back surface. Can also.

FIG. 2 schematically shows details of one pixel of the color filter obtained by the above process. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. The light transmitting portion inside the opening of the black matrix 2 is the pixel 20.

The ink applied to the colored portion gradually penetrates into the colored portion, but the ink spreads from the central portion to the peripheral portion of the pixel and penetrates, so that as shown in FIG. A region 21 having almost no density difference is formed near the center of the pixel 20, and a region 22 having a lower density than the region 21 is formed outside the region 21. When a pixel having such a density distribution is observed with a microscope, a region having a low density looks whitish as compared with other regions. However, even when a color filter having such pixels is visually observed, white spots and color unevenness may not be observed.

The present inventors have examined the relationship between white spots and color unevenness and the above-mentioned density distribution. As a result, when the density of the area 22 is very low compared to 21, the density of the area 22 is low and the density is low. It was found that when the area was large, white spots and color unevenness were observed.

FIGS. 3A and 3B are schematic diagrams when pixels are formed by reducing the amount of ink to be applied to the portion to be colored as compared with FIG. 2, wherein FIG. 3A is a plan view, and FIG. It is sectional drawing. As described above, when the area occupied by the low-density region 22 in the pixel 20 increases, color unevenness and white spots are observed when the color filter including such a pixel is visually observed.

The present inventors have optimized the density distribution by specifying the ratio of the density distribution to the area of the low-density region, thereby providing a color filter free from color unevenness and white spots. That is, in each pixel, by setting a region that is 15% or more thinner than the average density value in the pixel to 20% or less of the area of the pixel, a color filter without color unevenness or white spots can be obtained. Such density distribution is more likely to be affected by the B pixel than by the R and G pixels. Therefore, for the R and G pixels, the area that is 20% or more thinner than the average density value within the pixel may be set to 20% or less of the pixel area.

As a specific method for optimizing the density in the pixel as described above, in the present invention, in the ink applying step by the ink jet method, the size (diameter) of the ink dot at the time of impact is changed. Means for changing the size of the ink dots include a method of changing the amount of ink ejected and a method of changing the surface tension by changing the ink composition. Therefore, it is relatively easy to change the ink discharge amount. In order to change the ink ejection amount, the driving voltage or the driving pulse of the inkjet head may be changed.

Next, a method of manufacturing the second color filter of the present invention will be described. FIG. 4 is a process diagram thereof.
(A) to (e) are cross-sectional schematic views respectively corresponding to the following steps (a) to (e). The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

Step (a) First, a black resin layer 41 and a photosensitive silicon compound layer 42 are laminated on the substrate 1.

Step (b) The black resin layer 41 and the photosensitive silicon compound layer 42 are patterned. The patterned black resin layer 41 functions as a black matrix 43, and the photosensitive silicon compound layer 42 thereon functions as an ink-repellent layer. Note that the black matrix 43 also functions as a partition portion for avoiding color mixture with adjacent different colors of ink when ink described later is applied. The black matrix 43
Is preferably performed using a black pigment-containing resist and patterning by a general photolithography method.
In addition, the photosensitive silicon compound layer 42 does not need to be particularly provided, but in that case, it is preferable that the black resin layer 41 has ink repellency. In the present invention, the total thickness of the black matrix 43 and the photosensitive silicon compound layer 42 is preferably 0.5 μm or more in consideration of the above-mentioned partition effect.

Step (c) R, G, and B inks 44 are applied from the inkjet head 7 according to a predetermined coloring pattern so as to fill the openings of the black matrix 43. The ink is cured by applying energy, and a resin composition containing a colorant is preferably used. As the coloring agent, a general dye or pigment can be used. For example, as the dye, an anthraquinone dye, an azo dye, a triphenylmethane dye, a polymethine dye, or the like can be used.

As the resin used for the ink, a resin that is cured by energy application such as heat treatment or light irradiation is used. Specifically, a combination of a known resin and a crosslinking agent can be used as the thermosetting resin. For example, acrylic resin, melamine resin, hydroxyl or carboxyl group-containing polymer and melamine, hydroxyl or carboxyl group-containing polymer and polyfunctional epoxy compound, hydroxyl or carboxyl group-containing polymer and cellulose reaction type compound, epoxy resin and resol type resin, epoxy Examples include resins and amines, epoxy resins and carboxylic acids or acid anhydrides, and epoxy compounds. As the photocurable resin, a known resin, for example, a commercially available negative resist is preferably used.

Various solvents can be added to the ink. In particular, a mixed solvent of water and a water-soluble organic solvent is preferably used from the viewpoint of dischargeability in an inkjet method.

Further, in addition to the above-mentioned components, a surfactant, an antifoaming agent, a preservative, and the like can be added in order to give desired properties if necessary. Can be added.

Further, among the above-mentioned light or thermosetting resins, a solvent other than water or a water-soluble organic solvent may be used as long as it can be stably ejected even if it is not soluble in water or a water-soluble organic solvent. I do not care. In particular, when a monomer that polymerizes by light is used, a solventless type in which a dye is dissolved in the monomer may be used.

Step (d) Ink 44 applied to the opening of the black matrix 43
Is cured by heat treatment or light irradiation, or both, to form a colored portion 45.

Step (e) If necessary, a protective layer 10 is formed.

In the color filter obtained by the above process, since the colored portion is formed by curing the ink, if the ink is biased in the black matrix, a distribution occurs in the thickness of the colored portion in the pixel, The thickness distribution appears as it is as a concentration distribution. The above-mentioned thickness distribution is the thickest at the center of the pixel and becomes thinner toward the periphery in many cases. Therefore, the density at the periphery of the pixel is easily reduced.

With respect to the density distribution as described above, similarly to the color filter obtained by the process of FIG.
By specifying the ratio of the density distribution and the area ratio of the low-density region, the density distribution can be optimized and a color filter free from color unevenness and white spots can be obtained. That is, in each pixel, a region having a density of 15% or more with respect to the average density value in the pixel is set to 20% or less of the pixel area.

As a specific method for optimizing the density in a pixel as described above, the size (diameter) of the ink dot at the time of landing in the ink application step by the ink jet method is the same as in the step of FIG. Can be implemented by changing

Next, a liquid crystal device constituted by using the color filter of the present invention will be described. 5 is a schematic cross-sectional view of an embodiment of an active matrix type liquid crystal device incorporating the color filters formed in the process of FIG. 4 and FIG. 6, respectively. In FIGS. 5 and 6, 52 is a common electrode, 53 is an alignment film, 55 is a substrate, 56 is a pixel electrode, 57 is an alignment film, and 58 is a liquid crystal compound. Is attached.

A liquid crystal element for color display is generally formed by fitting a color filter side substrate (1) and a TFT substrate (55) and enclosing a liquid crystal compound 58. A TFT (not shown) is provided inside one substrate of the liquid crystal element.
And transparent pixel electrodes 56 are formed in a matrix. A color filter layer is provided inside the other substrate 1 so that the R, G, and B colored portions 9 and 45 are arranged at positions facing the pixel electrodes 56, and a transparent common layer is formed thereon. An electrode 52 is formed on one surface. Further, alignment films 53 and 57 are formed in the planes of both substrates, and by subjecting them to rubbing treatment, liquid crystal molecules can be aligned in a certain direction.

A polarizing plate (not shown) is bonded to the outside of each of the substrates 1 and 55, and a combination of a fluorescent lamp (not shown) and a scattering plate (not shown) is generally used as a backlight to back the liquid crystal compound. Display is performed by functioning as an optical shutter that changes the transmittance of the write light.

The liquid crystal element of the present invention may be configured using the color filter of the present invention, and the other components may be formed by applying the conventional liquid crystal element technology such as the material and manufacturing method. It is possible.

[0053]

EXAMPLE (Example 1) A color filter was manufactured according to the process shown in FIG. First, N was placed on a glass substrate on which a black matrix made of Cr having a predetermined opening was formed.
-Consisting of 10 parts by weight of a terpolymer of methylol acrylamide, methyl methacrylate and hydroxyethyl methacrylate and 0.4 parts by weight of triphenylsulfonium triflate, having an aqueous ink absorbency, and being irradiated with light or with irradiation with light and heat treatment. A resin composition having a reduced water-absorbing property at the light-irradiated portion and exhibiting water repellency to the ink is applied so as to have a film thickness of 1.0 μm, and prebaked at 60 ° C. for 10 minutes to form a resin composition layer. Formed.

Next, the pattern shape smaller than the black matrix was exposed with a high-pressure mercury lamp through a photomask, and heated on a hot plate at 110 ° C. for 90 seconds to form a colored portion and a non-colored portion, respectively.

Next, R, G, and B color inks were applied from the ink jet head to the colored portion along a predetermined coloring pattern. At this time, the size of the opening of the black matrix is 280 μm × 100 μm, and the dot diameter (diameter) of each ink when the ink lands is 8 for R, G and B.
It was adjusted to be 0 μm, and 10 dots of ink were applied per pixel.

Thereafter, the ink was dried at 90 ° C. for 30 minutes, and further heated at 230 ° C. for 60 minutes to completely cure the resin composition layer, thereby obtaining a color filter.

The density distribution (transmittance distribution) of each pixel of the obtained color filter was measured. The measurement was performed using a microspectrophotometer (“OSP-SP-200” manufactured by OLYNPUS) under the following conditions.

Wavelength: 610 nm (R), 545 nm
(G), 460 nm (B) Measurement spot diameter: 5 μm Pixel longitudinal direction: 280 μm Pixel lateral direction: 100 μm Step moving distance: 5 μm

FIG. 7 shows the measurement results of the transmittance of the cross section in the short direction of the R pixel. As is clear from FIG. 7, the transmittance gradually increases from the center of the colored portion toward the periphery of the pixel, and particularly the transmittance near the boundary with the black matrix increases. When the density distribution inside one pixel colored with R is measured, the density difference is 10% in the portion having the lowest density with respect to the average density value in the pixel, and the area of the region having a density lower than 15% is 0% of the pixel area.

Next, FIG. 8 shows the transmittance measurement results of the cross section of the G pixel in the lateral direction. As is clear from FIG. 8, the transmittance increases near the pixel periphery, but the difference between the center and the periphery of the pixel is smaller than R in FIG. 7, and the density is uniformly distributed as a whole. are doing. Therefore, phenomena such as color unevenness and white spots are difficult to visually confirm. The density distribution inside one pixel colored with G is such that the density difference is 20% in the portion where the density is the lightest with respect to the average density value in the pixel, and the area of the region where the density is 15% or more is the area of the pixel area. 5%.

FIG. 9 shows the results of measuring the transmittance of the cross section of the B pixel in the lateral direction. As is clear from FIG.
As in the case of R, the transmittance increases from the center of the colored portion toward the periphery of the pixel, but the degree is larger than that of R. For this reason, when the transmittance near the boundary with the black matrix becomes extremely large or when the portion having a large transmittance increases, phenomena such as color unevenness and white spots are more likely to occur than R and G. . The density distribution inside one pixel colored with B is such that the density difference is 15% in the portion where the density is the lightest with respect to the average density value in the pixel, and the area of the region where the density is 15% or more is 6% of the pixel area. %Met.

When the color filter of this example was visually observed, neither a white spot nor color unevenness was observed.

(Comparative Example 1) In the step of applying ink to the colored portion, the color was formed in the same manner as in Example 1 except that the drive voltage of the ink jet head was set small and the amount of ink discharged was adjusted to be small. A filter was made. The dot diameter (diameter) at the time of ink landing is R, G, B
Both were 60 μm, and 10 dots of ink were applied per pixel.

The density distribution of each pixel of the obtained color filter was measured under the same conditions as in Example 1. As a result, with respect to the density distribution in one pixel, for the R pixel, the density difference is 20% in the portion which is the lightest with respect to the average density value in the pixel, and the area of the region having a density of 20% or more is the area of the pixel area. 16
%, The area of a region having a density of 15% or more is 22% of the pixel area.
%, And for the G pixel, the density difference is 20% in the portion having the lowest density with respect to the average density value in the pixel, and 20%.
The area of a region having a low concentration of 20% or more is 15% or 20% of the pixel area.
The area of a region having a low density of 21% or more is 21% of the pixel area, and for the B pixel, the density difference is 25% in a portion having the lowest density with respect to the average density value in the pixel, and the density of 155 or more is low. The area of the region was 20% of the pixel area. Therefore, the area that is 15% or more thin for the R pixel and the G pixel exceeds 20%.

As a result of visually observing the color filter, slight white spots and color unevenness were observed.

Example 2 A color filter was formed in the same manner as in Example 1 except that the amount of ink to be applied to the portion to be colored was changed. The drive voltage of the inkjet head was set between Example 1 and Comparative Example 1, and the ejection amount of the ink was adjusted. The dot diameter (diameter) when the ink lands at this time is
Each of R, G, and B is 75 μm, and 10 dots per pixel.

The pixel density distribution of each of the obtained color filters was measured under the same conditions as in Example 1. As a result, with respect to the density distribution in one pixel, for the R pixel, the density difference is 15% in the portion having the lowest density with respect to the average density value in the pixel, and the area of the region in which the density is 20% or more is smaller than the pixel. 0 of area
%, The area of a region with a density of 15% or more is 6% of the pixel area
For the G pixel, the density difference is 20% in the portion which is the lightest with respect to the density average value in the pixel, and the area of the light density region of 20% or more is 7% of the pixel area, The area of the thin region is 9% of the pixel area. For the B pixel, the density difference is 20% for the portion having the lowest density with respect to the average density value in the pixel, and the area of the thin region having a density of 15% or more is small. Was 10% of the pixel area.

When the above color filter was visually observed, neither a white spot nor color unevenness was found.

Further, the dot diameter (diameter) at the time of impact is
50 μm, 65 μm, 70 μm, 90 for R, G and B
A color filter was manufactured by adjusting the driving voltage of the ink jet head so as to be μm, and the density distribution of each pixel was measured under the same conditions as in Example 1. The results are shown in FIGS.
It is shown in FIG.

FIGS. 10 to 12 show the dot diameter of each ink and the average value of the density in each pixel based on the density distribution measurement results of each pixel in Example 1, Comparative Example 1, and this example. FIG. 6 is a diagram showing the ratio of the area of a region having a density lower than 15% to the pixel area with respect to the pixel area. FIG. 13 and FIG. 14 are diagrams showing the dot diameter of ink landing for each pixel of R and G, and the ratio of the area of the area where the density is 20% or more smaller than the average density value in the pixel to the pixel area. It is.

As shown in FIGS. 13 and 14, R and G
When the area of a region where the density is 20% or less with respect to the density average value is 20% or less of the pixel area,
Although slight white spots and color unevenness are of a degree that does not affect the color filter, as shown in FIGS. 11 and 12, when the area of the region where the density is 15% or more and light is 20% or less of the pixel area, No white spots or color unevenness are visually observed. As for the B pixel, as shown in FIG. 10, when the area of a region whose density is 15% or more smaller than the average density value is 20% or less of the pixel area, the influence of white spots and color unevenness is reduced. It can be reduced and provided as a color filter.

As described above, it is possible to manufacture a color filter free from white spots and color unevenness by controlling the landing dot diameter of the ink from the ink jet head.

Example 3 A color filter was manufactured according to the process shown in FIG. First, a light-shielding resin composition obtained by dispersing a black pigment in a cresol novolak resin was formed on a glass substrate so as to have a thickness of 1.0 μm. further,
A photosensitive silicon compound comprising an alkali-soluble polysilsesquioxane and a naphthoquinonediazide ester is spin-coated so as to have a thickness of 0.3 μm.
Prebaking for 0 minutes was performed.

Next, pattern exposure is performed using a photomask that shields a region to be a colored portion from light, and the resin composition layer and the photosensitive silicon compound layer are developed by immersion in an alkaline aqueous solution to form a silicon compound layer on the surface. The obtained black matrix substrate was obtained.

Next, a thermosetting R, comprising water, an organic solvent, a melamine resin and a pigment, is supplied from an ink jet head.
G and B inks were applied to the openings of the black matrix along a predetermined coloring pattern. The size of the opening of the black matrix is 280 μm × 100 μm, and the dot diameter (diameter) when each ink lands is R,
G and B were both 80 μm, and 10 dots of ink were applied per pixel.

Thereafter, at 90 ° C. for 5 minutes, and further at 230 ° C.
The ink was completely cured by a heat treatment for 30 minutes, and a protective layer was formed to form a color filter.

The density distribution in each pixel of the obtained color filter was measured in the same manner as in Example 1. As a result, as for the R pixel, the density difference was 15% in the portion having the lowest density with respect to the average density value in the pixel, and the area of the region having the density lower than 15% was 3% of the pixel area. As for the G pixel, the density difference was 15% in a portion where the density was the lowest with respect to the average density value in the pixel, and the area of a region having a density of 15% or more was 5% of the pixel area. As for the B pixel, the density difference was 15% in the portion where the density was the lowest with respect to the average density value in the pixel, and the area of the region where the density was 15% or more was 5% of the pixel area.

When the obtained color filter was visually observed, white spots and color unevenness were not observed.

(Embodiment 4) In the step of applying ink to the openings of the black matrix, the process is performed in the same manner as in Embodiment 3 except that the drive voltage of the ink jet head is set small so as to reduce the amount of ejected ink. To produce a color filter. The dot diameter (diameter) at the time of ink landing was 60 μm for each of R, G and B, and 10 dots of ink were applied per pixel.

The density distribution of each pixel of the obtained color filter was measured under the same conditions as in Example 1. As a result, with respect to the density distribution within one pixel, for the R pixel, the density difference is 20% at the portion having the lowest density with respect to the average density value within the pixel.
Where the area of a region having a light density of 15% or more is 20% of the pixel area, and for the G pixel, the density difference is 20% in a portion having the lightest density with respect to the density average value in the pixel;
The area of a region having a light density of 15% or more is 20% of the pixel area. For the B pixel, the density difference is 20% in a portion having the lightest density with respect to the density average value in the pixel, and the density difference is 15% or more. Area was 20% of the pixel area.
Therefore, in any pixel, the region thinner by 15% or more did not exceed 20% of the pixel area.

When the color filter was observed with an optical microscope, a slight deviation in thickness was observed within the pixel, but no white spots or color unevenness were observed as a result of visual observation.

[0082]

As described above, according to the present invention,
A highly reliable color filter free from white spots and color unevenness is reliably provided, and a liquid crystal element excellent in color display can be formed using the color filter.

[Brief description of the drawings]

FIG. 1 is a process chart of a first method for manufacturing a color filter of the present invention.

FIG. 2 is a view showing a colored portion in the step of FIG. 1;

FIG. 3 is a diagram illustrating a colored portion when the ink ejection amount is reduced in the process of FIG. 1;

FIG. 4 is a process chart of a second method for manufacturing a color filter of the present invention.

FIG. 5 is a schematic cross-sectional view of an example of the liquid crystal element of the present invention.

FIG. 6 is a schematic sectional view of another example of the liquid crystal element of the present invention.

FIG. 7 is a diagram illustrating transmittance of a cross section in the short direction of an R pixel according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating the transmittance of a G pixel in a lateral cross section according to the first embodiment of the present invention.

FIG. 9 is a diagram illustrating a transmittance of a cross section in a lateral direction of a B pixel according to the first embodiment of the present invention.

FIG. 10 shows R in Examples 1 and 2 of the present invention and Comparative Example 1.
FIG. 7 is a diagram showing the ratio of the area of a region where the density is 15% or more thinner to the pixel area with respect to the landed dot diameter of a pixel and the average density value within the pixel.

FIG. 11 shows G in Examples 1 and 2 of the present invention and Comparative Example 1.
FIG. 7 is a diagram showing the ratio of the area of a region where the density is 15% or more thinner to the pixel area with respect to the landed dot diameter of a pixel and the average density value within the pixel.

FIG. 12 shows B in Examples 1 and 2 and Comparative Example 1 of the present invention.
FIG. 7 is a diagram showing the ratio of the area of a region where the density is 15% or more thinner to the pixel area with respect to the landed dot diameter of a pixel and the average density value within the pixel.

FIG. 13 shows R in Examples 1 and 2 of the present invention and Comparative Example 1.
FIG. 5 is a diagram showing the ratio of the area of a region where the density is 20% or more smaller than the pixel area to the landed dot diameter of the pixel and the average density value within the pixel.

FIG. 14 shows G in Examples 1 and 2 of the present invention and Comparative Example 1.
FIG. 5 is a diagram showing the ratio of the area of a region where the density is 20% or more smaller than the pixel area to the landed dot diameter of the pixel and the average density value within the pixel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Black matrix 3 Resin composition layer 4 Photomask 5 Non-colored part 6 Colored part 7 Ink-jet head 8 Ink 9 Colored part 10 Protective layer 20 Pixel 21 Area with uniform concentration 22 Area with low concentration 41 Black resin layer 42 Photosensitive silicon compound layer 43 Black matrix 44 Ink 45 Colored part 52 Common electrode 53 Alignment film 55 Substrate 56 Pixel electrode 57 Alignment film 58 Liquid crystal compound

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Akadaira 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Satoshi Wada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated F term (reference) 2C056 EA24 FB01 2H042 AA09 AA26 2H048 BA02 BA64 BB02 BB14 BB15 BB22 BB37 BB44 2H091 FA02Y FC01 FD24 2H096 AA28 FA10 JA03

Claims (7)

[Claims] 1. A color filter comprising, as pixels, a light-shielding portion and a colored portion located at an opening of the light-shielding portion on a transparent substrate, wherein each pixel has a density of 15% with respect to an average density value in the pixel. The region having a low density is 2% of the area of the pixel.
A color filter characterized by being 0% or less. 2. The color filter according to claim 1, wherein the low-density region exists in a peripheral portion of each pixel. 3. A pixel having at least three color pixels of red, green, and blue, and in the red and green pixels, a region whose density is 20% or more of the density average value in the pixel is the area of the pixel. The color filter according to claim 1, which is 20% or less of the following. 4. The color filter according to claim 3, wherein the low-density region exists in a peripheral portion of each pixel. 5. The method for manufacturing a color filter according to claim 1, wherein a light-shielding portion having an opening corresponding to the pixel is formed on the transparent substrate, and light irradiation or light irradiation is performed. Forming a resin composition layer that reduces or increases the ink absorbency by heat treatment, and performing light irradiation or light irradiation and heat treatment on a predetermined region of the resin composition layer to at least light-shield the colored portion having high ink absorbency. In the opening of the portion, a non-colored portion having a lower ink absorption than the colored portion is formed on at least a part of the light-shielding portion. A method for producing a color filter, characterized in that the resin composition layer is colored by applying light and heat treatment is performed on the entire resin composition layer. 6. The method for manufacturing a color filter according to claim 1, wherein a light-shielding portion having an opening corresponding to the pixel is formed on the transparent substrate, and the opening of the light-shielding portion is formed. Ink that is cured by applying energy to the ink while controlling the dot diameter by the inkjet method,
A method for producing a color filter, comprising curing the ink by applying energy. 7. A liquid crystal element having a liquid crystal sandwiched between a pair of substrates, wherein one of the substrates is formed using the color filter according to claim 1. Liquid crystal element.