JP2001183514A - Color filter and its manufacturing method, liquid crystal element using color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a color irregularity due to distribution of discharged quantities among individual nozzles, in a manufacturing method of a color filter using an inkjet head provided with plural nozzles. SOLUTION: In the manufacturing method, the number of ink drops discharged to the one part to be colored is controlled by adjusting the pitch of the discharge so as to maintain the discharged quantity per nozzle at a time in the range corresponding to <=10% of the ink quantity discharged to the one part to be colored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device for color display used in a color television, a personal computer, a pachinko game machine, and the like, a color filter as a constituent member of the liquid crystal device, and a method of manufacturing the same.

[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, for further widespread use, it is necessary to reduce the cost of the liquid crystal display. In particular, there is an increasing demand for reducing the cost of a color filter having a high specific gravity. 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 that satisfies all the required characteristics. The respective methods will be described below.

The first method is a pigment dispersion method. In this method, a photosensitive resin layer in which a pigment is dispersed is formed on a transparent substrate, and a monochromatic pattern is obtained by patterning the photosensitive resin layer. By repeating this step three more times, R
(Red), G (green), and B (blue) colored layers are formed.

[0004] The second method is a dyeing method. In the dyeing method, a water-soluble polymer material, which is a material for dyeing, is applied on a transparent substrate, and is patterned into a desired shape by a photolithography process. Get a pattern. By repeating this three times, three colored layers of R, G and B are formed.

A third method is an electrodeposition method. In this method, a transparent electrode is patterned on a transparent substrate, immersed in an electrodeposition coating solution containing a pigment, a resin, an electrolytic solution, etc., to form a first electrode.
Electrodeposit the color. This process is repeated three times and finally baked to form R, G, and B colored layers.

As a fourth method, there is a printing method. This method is a method in which a pigment is dispersed in a thermosetting resin, R, G, and B are separately applied by repeating printing three times, and then the resin is thermoset to form a colored layer.

In any of the above methods, a protective layer is generally formed on the colored layer. Also, these methods have in common that the same process needs to be repeated three times to color the three colors R, G, and B, which increases the cost. There is also a problem that the yield decreases as the number of steps 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 liquid crystal element using a TFT (thin film transistor). Further, the printing method has poor resolution and smoothness, so that it is difficult to form a fine pitch pattern.

In order to make up for these drawbacks, Japanese Patent Laid-Open Publication No.
JP-A-5205, JP-A-63-235901 and JP-A-1-217320 disclose a method of manufacturing a color filter using an ink jet method. In this method, ink containing three colorants of R, G, and B is ejected onto a transparent substrate by an inkjet method, and each ink is dried to form a colored portion. According to this method, it is possible to form each of the R, G, and B colored portions at one time, and it is possible to greatly simplify the manufacturing process and achieve a significant cost reduction effect.

FIG. 1 schematically shows a coloring process of a color filter by an ink-jet method. In the figure, 1 is a transparent substrate, 2 is a portion to be colored, 3R, 3G, and 3B are inkjet heads for discharging R, G, and B inks, and 4 is a nozzle.

As shown in FIG. 1, ink-jet heads 3R to 3B having a plurality of nozzles 4 are used, and the ink-jet heads 3R to 3B are arranged at an angle such that the pitch of the nozzles 4 corresponds to the pitch of the portion 2 to be colored. Then, ink of each color is ejected onto the colored portion 2 while scanning the transparent substrate 1.

[0011]

SUMMARY OF THE INVENTION As shown in FIG.
When a colored portion is formed by discharging ink onto the portion to be colored 2 while scanning an inkjet head having a plurality of nozzles, and when the amount of ink discharged between the nozzles varies, a direction perpendicular to the scanning direction is used. However, there is a problem that density unevenness occurs between colored portions arranged in a row.

[0012] Such variation in the discharge amount between nozzles.
Is called shading correction.
There is. In this method, as shown in FIG.
Of the nozzles 4a to 4c of the printhead 3 (the
(Expressed in size) are different, as shown in FIG.
Adjust the discharge pitch according to the discharge amount of each nozzle.
With this, the amount of ink ejected to each colored portion 2 is made constant.
You. That is, when the discharge amount of the nozzle 4c is used as a reference, the discharge
The nozzle 4b having a large amount has a discharge pitch_bFrom the nozzle 4c
Outgoing pitch t_cNozzle 4a which is wider than the above and has a small discharge amount
Is the ejection pitch t_aTo t _cMake it narrower.

However, even when the above-described shading correction is performed, when the color filters of the delta arrangement as shown in FIG. 4 are colored, color unevenness is likely to occur.

An object of the present invention is to solve the above problems, to produce a color filter with a high yield by preventing the occurrence of color unevenness by a simple method, and to use the color filter to produce a liquid crystal element excellent in color display. It is to provide at low cost.

[0015]

A method of manufacturing a color filter according to the present invention is a method of manufacturing a color filter having a plurality of colored portions on a transparent substrate, wherein the ink jet head is provided with a plurality of nozzles on the transparent substrate. Forming a colored portion by simultaneously ejecting ink droplets to a plurality of portions to be colored on the transparent substrate while scanning with the nozzle. In the range of 10% or less of the amount of ink ejected to the colored portion, the number of ink droplets ejected to one colored portion is adjusted for each nozzle, thereby compensating for the difference in the ejected amount between the nozzles.

In the present invention, the discharge amount of each nozzle at one time is preferably 2% or less of the ink amount discharged to one color-receiving portion. In particular, the transparent substrate has a diagonal size of 200 mm or more. Is preferably applied.

Further, according to the present invention, an ink receiving layer comprising a photosensitive resin composition is formed on a transparent substrate, and the ink receiving layer is subjected to pattern exposure to obtain a color-receiving portion having an ink receiving ability; Forming a non-colored portion having a lower ink receiving capacity than the portion, and coloring the portion to be colored by discharging ink from an inkjet head, or forming a colored portion, or a resin layer having an opening on a transparent substrate And forming a colored portion by discharging an ink made of a curable coloring resin composition from an ink jet head using an opening of the resin layer as a portion to be colored and curing the ink.

Further, according to the present invention, there is provided a color filter having a plurality of colored portions on a transparent substrate and manufactured by the method for manufacturing a color filter of the present invention, and a liquid crystal between a pair of substrates. And a liquid crystal element characterized in that one of the substrates is formed using the color filter of the present invention.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a color filter according to the present invention basically performs the above-described shading correction. That is, in accordance with the discharge amount of each nozzle, the discharge pitch is increased for a nozzle having a large discharge amount with respect to the discharge amount of the reference nozzle (for example, based on the average value of the discharge amounts of all nozzles). Reduces the number of ink droplets ejected from the nozzle to one colored portion, and increases the number of ink droplets ejected from the nozzle to one colored portion by reducing the ejection pitch for nozzles with a small amount of ejection. In addition, the amount of ink ejected to each colored portion is made constant. Note that one colored portion refers to a colored region surrounded by non-colored portions that are not colored with ink from the inkjet head.

At this time, in the present invention, one of the nozzles
The ejection amount per time (one drop) is set so as to be 10% or less of the ink amount ejected to one colored portion. In particular,
The setting can be easily made by changing the ink jet head to be used or adjusting the ink amount by adjusting the ink density.

As a result, the fluctuation range per one ink droplet becomes 10% or less of the ink amount of one colored portion, and the density distribution within the same substrate is at most 10% or less, and substantially The occurrence of color unevenness is prevented. Further, it is desirable that the amount of one discharge of each nozzle is 2% or less of the amount of ink discharged to one coloring target portion, and it is particularly effective in the case of a color filter having a substrate size of 200 mm or more diagonally. It is.

In the present invention, as shown in FIG.
Either a color filter in which the long colored portions 2 are arranged in a stripe pattern in parallel, or a color filter in a delta arrangement in which a plurality of rows and columns are formed two-dimensionally as shown in FIG. This is also preferably applied, and is particularly effective in the case of the delta arrangement shown in FIG. 4 in which the number of ejected ink droplets is small.

Hereinafter, the present invention will be described with reference to embodiments. More specifically, in the method of manufacturing a color filter of the present invention, an ink receiving layer made of a photosensitive resin composition is formed on a transparent substrate, The ink receiving layer is subjected to pattern exposure to form a colored portion having ink receiving capability and a non-colored portion having lower ink receiving capability than the colored portion, and ink is ejected from the inkjet head to the colored portion. Coloring, a method of forming a colored portion, or forming a resin layer having an opening on a transparent substrate, using the opening of the resin layer as a portion to be colored, an ink comprising a curable coloring resin composition from an inkjet head. A method of discharging and curing to form a colored portion is preferably used.

FIG. 5 schematically shows the steps of one embodiment of the method for manufacturing a color filter of the present invention. In this embodiment,
In this embodiment, the ink receiving layer is colored to form a colored portion. In the figure, 11 is a transparent substrate, 12 is a black matrix, 13 is an ink receiving layer, 14 is a photomask, 15
Is a non-colored portion, 16 is a portion to be colored, 17 is an inkjet head, 18 is ink, 19 is a colored portion, and 20 is a protective layer. 5A to 5F are schematic sectional views respectively corresponding to the following steps (a) to (f).

Step (a) On the transparent substrate 11, a black matrix 1
Form 2 As the transparent substrate 11, glass is generally used, but plastics or the like can also be used as long as they do not impair the transparency of the color filter and have necessary characteristics such as strength. In addition, the black matrix 12
May be a black stripe, and its film thickness is usually 0.1 mm.
It is about 1 to 0.5 μm, and is obtained by forming a metal such as chromium on the transparent substrate 11 by sputtering or vapor deposition and patterning.

Step (b) An ink receiving layer 13 made of a photosensitive resin composition is formed on the entire surface of the transparent substrate 11. The ink receiving layer 13 is a coloring medium for forming a colored portion 19 by coloring in a step described later, and is formed of a photosensitive resin composition whose ink receiving ability changes by light irradiation or light irradiation and heat treatment. In the process, a non-colored portion 15 for preventing color mixture is formed by pattern exposure. As the photosensitivity, any of a negative type and a positive type may be used, and specifically, an acrylic resin, an epoxy resin, a silicone resin, hydroxypropylcellulose, hydroxyethylcellulose, methylcellulose,
A cellulose derivative such as carboxymethyl cellulose or a modified product thereof, an amide resin, a phenol resin, a polystyrene resin, and the like are used in combination with a photoinitiator (crosslinking agent) as necessary. As the photoinitiator, a dichromate, a bis azide compound, a radical initiator, a cationic initiator, an anionic initiator and the like can be used, and further, these photoinitiators can be mixed or used. Can be used in combination with a sensitizer. Furthermore, a photoacid generator such as an onium salt can be used as a crosslinking agent. This embodiment shows an example in which a negative resin composition that loses (or reduces) ink receptivity by light irradiation is used.

The photosensitive resin composition may be spin-coated,
The ink receiving layer 13 is formed by coating the transparent substrate 11 by a method such as roll coating, bar coating, spray coating, or dip coating, and prebaking as necessary. The thickness of the ink receiving layer 13 is usually about 0.3 to 3.0 μm.

Step (c) Using the photomask 14, the ink receiving layer 13 is subjected to pattern exposure to eliminate (or reduce) the ink receptivity of the exposed portion to form the non-colored portion 15. The non-colored portion 15 is formed at a position overlapping the black matrix 12. In particular, the non-colored portion 15 is formed to be narrower than the width of the black matrix 12 from the viewpoint of preventing white spots at the boundaries of the openings of the black matrix 12. Is preferred. In order to enhance the effect of preventing color mixing, the non-colored portion 15
Is a component which exhibits ink repellency.
Is preferably applied.

The area not exposed in this step becomes the portion to be colored 16. When a positive-type resin composition that develops (or increases) ink receptivity upon exposure is used, exposure may be performed in the reverse pattern.

Step (d) Ink 18 of a predetermined color is discharged from the ink jet head 17 to the portion 16 to be colored along a predetermined coloring pattern to be colored. In the present invention, in the step,
As described above, the number of ink droplets to be ejected to one coloring portion 16 is adjusted by adjusting the number of ink droplets to be ejected to one coloring portion 16 in a range where the amount of one ejection of the nozzle is 10% or less of the amount of ink ejected to one coloring portion 16. Compensate for the difference in the discharge amount between nozzles.

As the ink jet system used in the present invention, a bubble jet type using an electrothermal transducer as an energy generating element, a piezo jet type using a piezoelectric element, or the like can be used. Can be set arbitrarily.

The ink 18 used for coloring the ink receiving layer 13 in the present invention is preferably used as long as it contains a coloring agent such as a dye or a pigment and is liquid at the time of ejection.

Step (e) A necessary treatment such as heat treatment or light irradiation is performed to cure the entire ink receiving layer, thereby forming a colored layer including a non-colored portion 15 and a colored portion 19.

Step (f) If necessary, a protective layer 20 is formed on the colored layer to obtain the color filter of the present invention. As the protective layer 20, a resin composition layer of a photo-curing type, a thermosetting type, or a combination of heat and light, or an inorganic film formed by vapor deposition, sputtering, or the like can be used. In any case, any material can be used as long as it has transparency as a color filter and can withstand the subsequent ITO forming step, alignment film forming step, and the like.

Next, FIG. 6 schematically shows the steps of another embodiment of the method for manufacturing a color filter of the present invention. The present embodiment is an embodiment in which a colored portion is formed using a curable colored resin composition as the ink. In the figure, reference numeral 22 denotes a black matrix, 28 denotes ink, and 29 denotes a colored portion, and the same members as those in FIG. 6A to 6D are cross-sectional views corresponding to the following steps (a) to (d), respectively.

Step (a) A resin layer having an opening is formed on the transparent substrate 11.
The resin layer is a member that functions as a partition for containing ink. In the present embodiment, the resin layer is formed of a black resin, and the black matrix 22 that also functions as a light-shielding layer that shields between adjacent colored portions 29 is formed. Here is an example. Such a black matrix 22 can be formed by using a black pigment resist and patterning by general photolithography. Further, it is preferable that the black matrix 22 be provided with ink repellency in order to prevent color mixture when ink to be described later is ejected. The thickness of the black matrix 22 is preferably 0.5 μm or more in consideration of the partition wall function and the light shielding function.

Step (b) The ink 28 of a predetermined color is ejected from the ink jet head 17 along a predetermined coloring pattern using the opening of the black matrix 22 as a portion to be colored. In the present invention, in the step, as described above, one of the nozzles is used.
The discharge amount per time is 10 times the amount of ink discharged to one colored portion.
In the range of% or less, the number of ink droplets ejected to one colored portion is adjusted to compensate for the difference in the ejection amount between the nozzles.

The ink 28 used in the present invention is
It is a curable colored resin composition and contains at least a colorant such as a dye or a pigment, and a resin that is cured by heat treatment or application of energy such as light irradiation. For example, as the thermosetting resin composition, a combination of a known resin and a crosslinking agent can be used, and specifically, a melamine resin, a hydroxyl- or carboxyl-containing polymer and melamine, a hydroxyl- or carboxyl-containing polymer and a polyfunctional epoxy Examples include compounds, hydroxyl- or carboxyl-containing polymers and cellulose-reactive compounds, epoxy resins and resole resins, epoxy resins and amines, epoxy resins and carboxylic acids or acid anhydrides, and epoxy compounds. As the photocurable resin composition, a commercially available negative resist is preferably used.

Various solvents can be used for the curable ink. In particular, a mixed solvent of water and a water-soluble organic solvent is preferably used from the viewpoint of ejection properties when used in an inkjet method.

Further, in addition to the above components, a surfactant, an antifoaming agent, a preservative, and the like can be used in order to give desired characteristics as required. Further, a commercially available water-soluble dye or the like can be added. You can also.

In addition, 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 insoluble in water or a water-soluble organic solvent. I don't care. In particular, when a curable compound of a type polymerizable by light is used, a solventless type in which a dye is dissolved in a monomer may be used.

Step (c) The ink 28 is cured by performing necessary processing such as heat treatment or light irradiation, and a colored portion 29 is formed.

Step (d) If necessary, the protective layer 20 is formed on the colored portion 29 to obtain the color filter of the present invention.

Next, FIG. 7 is a schematic sectional view of one embodiment of the liquid crystal element of the present invention. The present embodiment is an example in which a TFT type color liquid crystal element is formed using the color filter of the present invention obtained by the process of FIG. In the figure, 31 is a counter substrate, 32 is a pixel electrode, 33 and 35 are alignment films, 34 is a common electrode, and 36 is a liquid crystal. The same members as those in FIG.

In general, the color liquid crystal element is formed by combining the substrate 11 on the color filter side and the opposing substrate 31 to form a liquid crystal 3.
6 is formed. TFTs (not shown) and pixel electrodes 32 are formed in a matrix inside one substrate 31 of the liquid crystal element. Further, inside the substrate 11 on the color filter side, a colored portion 19 of a color filter is formed at a position facing the pixel electrode 32 so that R, G, and B are arranged, and a transparent common electrode is formed thereon. 34 are formed. The black matrix 12 is usually formed on the color filter side, but may be formed on the counter substrate 31 side such as a BM-on-array type liquid crystal element. further,
Alignment films 33 and 35 are formed in the planes of both substrates.
Liquid crystal molecules are arranged in a certain direction. These substrates are opposed to each other via a spacer (not shown), are bonded by a sealing material (not shown), and a gap is filled with a liquid crystal 36.

In the case of the transmission type liquid crystal element, the substrate 31 and the pixel electrode 32 are formed of a transparent material, a polarizing plate is adhered to the outside of each substrate, and a fluorescent lamp and a scattering plate are generally combined. The display is performed by using the backlight and using the liquid crystal compound as an optical shutter for changing the transmittance of the backlight. In the case of the reflection type, the substrate 31 or the pixel electrode 32 is formed of a material having a reflection function, or a reflection layer is provided on the substrate 31, a polarizing plate is provided outside the transparent substrate 11, and a color plate is provided. Display is performed by reflecting light incident from the filter side.

In the liquid crystal device of the present invention, as long as it is constituted by using the color filter of the present invention, it is needless to say that the conventional technology can be used as it is for the other members.

[0048]

EXAMPLE A color filter was manufactured according to the steps shown in FIG.

A Cr film having a thickness of 0.5 μm was formed on a glass substrate and patterned to form a black matrix having an opening of 88 μm × 265 μm. Further, an ink-receiving layer made of a mixture of an acrylamide-based resin and an acrylate-based resin is formed on the entire surface, and pattern exposure is performed through a photomask narrower than the black matrix to expose the exposed area to a non-ink-receiving area. The colored portion was used. An aqueous ink in which a dye for a color filter was dissolved was ejected to the colored portion to be colored, and a heat treatment was performed at 230 ° C. for 30 minutes to form a colored portion.

In the above-mentioned coloring step, the amount of one ejection from the nozzle is intentionally changed to adjust the number of ink drops to be injected into one colored portion, and it is determined whether unevenness is recognized at that time. Examined.

As a result, in the case of a substrate having a diagonal length of 200 mm or more, no color unevenness was recognized when the discharge amount per discharge was 10% or less. Further, in the case of a substrate having a diagonal of 200 mm or more, color unevenness is recognized when it exceeds 10%, and there is substantially no hindrance when it exceeds 2% and 10% or less.
Below, no color unevenness was recognized.

Next, in the same process as described above, a color filter (pixel size: 102.5 μm × 307.5 μm) for a 12.1 inch SVGA class liquid crystal element is applied to the ink jet recording apparatus at a discharge amount of 5 to 10 pl. It was produced by mounting an ink jet head. When the ink ejection amount of the nozzle of the used inkjet head was measured in advance, the average ejection amount was 7.0 pl, and the ejection amount unevenness between nozzles was up to 20%. Therefore, the dye in the ink is set to about 5% by mass so that the amount of ink required for one colored portion is 400 pl, and for each nozzle, 400 pl is divided by the ejection amount and rounded to obtain the necessary ink droplet. The number was determined.
The number of ink drops required for one colored portion is 5
The ratio of one ejection amount to the amount of ink ejected to one colored portion is 1.9 for the nozzle having the maximum ejection amount.
%Met. The color filter obtained in this step had no color unevenness and was very good.

[0053]

As described above, according to the present invention,
A color filter without color unevenness can be easily manufactured with good yield without fine control of the discharge amount for each nozzle, and a liquid crystal element having excellent color display characteristics can be provided at a lower cost using the color filter. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a schematic plan view illustrating a coloring process of a color filter using an inkjet head.

FIG. 2 is a schematic plan view showing a discharge amount distribution of nozzles of an inkjet head.

FIG. 3 is a schematic plan view showing a method for correcting the ejection amount distribution of the nozzles of the inkjet head.

FIG. 4 is a schematic plan view of a color filter in a delta arrangement.

FIG. 5 is a view schematically showing steps of one embodiment of a method for manufacturing a color filter of the present invention.

FIG. 6 is a view schematically showing steps of another embodiment of the method for manufacturing a color filter of the present invention.

FIG. 7 is a schematic cross-sectional view of one embodiment of the liquid crystal element of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 colored portion 3, 3R, 3G, 3B inkjet head 4, 4a-4c nozzle 5 ink droplet 11 transparent substrate 12 black matrix 13 ink receiving layer 14 photomask 15 non-colored portion 16 colored portion 17 inkjet head 18 ink Reference Signs List 19 colored portion 20 protective layer 22 black matrix 28 ink 29 colored portion 31 counter substrate 32 pixel electrode 33, 35 alignment film 34 common electrode 36 liquid crystal

Claims (7)

[Claims] 1. A method of manufacturing a color filter having a plurality of colored portions on a transparent substrate, the method comprising: scanning a transparent substrate with an inkjet head having a plurality of nozzles while scanning a plurality of colored portions on the transparent substrate. And forming a colored portion by simultaneously ejecting ink droplets to the portion, in which the amount of one discharge of each nozzle is 10% or less of the amount of ink ejected to one portion to be colored. A method of manufacturing a color filter, comprising: adjusting the number of ink droplets ejected to one coloring portion for each nozzle to compensate for a difference in the ejection amount between the nozzles. 2. The method for manufacturing a color filter according to claim 1, wherein the amount of one ejection of each nozzle is 2% or less of the amount of ink ejected to one colored portion. 3. The method for manufacturing a color filter according to claim 2, wherein the transparent substrate has a diagonal dimension of 200 mm or more. 4. An ink receiving layer made of a photosensitive resin composition is formed on a transparent substrate, and the ink receiving layer is subjected to pattern exposure to form a portion to be colored having an ink receiving ability, and a portion to receive ink more than the portion to be colored. The method for producing a color filter according to claim 1, wherein a non-colored portion having low performance is formed, and the colored portion is formed by discharging ink from the inkjet head to the colored portion to form a colored portion. 5. A resin layer having an opening is formed on a transparent substrate, and the opening of the resin layer is used as a portion to be colored, and an ink composed of a curable coloring resin composition is discharged from an inkjet head to be cured and colored. The method for producing a color filter according to claim 1, wherein the portion is formed. 6. A color filter having a plurality of colored portions on a transparent substrate and manufactured by the method for manufacturing a color filter according to claim 1. 7. A liquid crystal element comprising liquid crystal sandwiched between a pair of substrates, wherein one of the substrates is formed using the color filter according to claim 6.