JP4785236B2 - Manufacturing method of liquid crystal element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color liquid crystal element used in a color television, a personal computer, a pachinko game machine, and the like, and in particular, a color filter provided with a color filter on the active matrix substrate side on which a switching element for driving a pixel electrode is formed. The present invention relates to an on-array liquid crystal element and a manufacturing method for manufacturing the liquid crystal element by using an inkjet method.
[0002]
[Prior art]
Currently, a liquid crystal element generally used has a configuration in which liquid crystal is sandwiched between two glass substrates having electrodes, and the periphery of both substrates is fixed with a sealing adhesive. The distance between the two substrates is kept constant by interposing plastic beads having a uniform particle diameter as spacers between the substrates.
[0003]
Further, the liquid crystal element for color display has a color filter composed of colored portions of R (red), G (green), and B (blue) formed on one of the two glass substrates. In an active matrix liquid crystal device, a thin film transistor (TFT) having amorphous silicon (a-Si) or polysilicon (p-Si) as a semiconductor layer, a pixel electrode connected thereto, an information signal line, a scan A TFT array substrate, which is an active matrix substrate on which signal lines are formed, and a counter substrate having a counter electrode disposed opposite to the substrate and having a color filter formed thereon, and polarizing plates are arranged on both sides of the element Thus, a color image can be displayed. As a display method of the liquid crystal element, for example, a TN (twisted nematic) type, an STN (super twisted nematic) type, a GH (guest / host) type, an ECB (birefringence control) type, a ferroelectric liquid crystal, or the like is used. In any case, it is advantageous in manufacturing to provide a color filter layer on the counter substrate side where the electrode configuration is simple. However, in order to take into account misalignment with the active matrix substrate, it is necessary to make the light-shielding layer of the color filter layer smaller than the pixel opening of the active matrix substrate, which causes a decrease in the aperture ratio.
[0004]
Incidentally, in recent years, there has been a demand for a high aperture ratio of pixels in order to realize high brightness of a liquid crystal panel. With the increase in the aperture ratio of pixels, development of further high-precision alignment technology in manufacturing facilities is being performed. However, it is difficult to increase the aperture ratio beyond this point due to the construction method.
[0005]
Therefore, in recent years, a color filter-on-array structure has been developed in which a color filter is formed on an active matrix substrate and alignment is not required during assembly. This color filter-on-array structure eliminates the need for alignment between the active matrix substrate on which the color filter is formed and the counter substrate on which the electrodes are formed on the entire surface, eliminates misalignment when assembling the substrate, and reduces the amount of alignment work. It becomes unnecessary and the process can be simplified. In addition, since there is no problem of alignment accuracy when combining both substrates, it is possible to design a pattern that does not allow for this alignment error, and it is possible to realize the ultimate high aperture ratio by further narrowing the pattern width of the light shielding layer. .
[0006]
Various methods such as a dyeing method, a pigment dispersion method, an electrodeposition method, and a film transfer method have been developed as methods for forming color filters in these color filter-on-arrays.
[0007]
[Problems to be solved by the invention]
However, in the conventional color filter-on-array structure, since each colored portion of the color filter is formed between the switching element and the pixel electrode, a contact hole is formed in each colored portion. It was necessary to make the pixel electrode and the switching element conductive through each other. Therefore, when the color filter manufacturing method is developed in a color filter on array, the formation of this contact hole becomes an important issue.
[0008]
An example of developing a color filter manufacturing method in a color filter on array is disclosed in Japanese Patent Laid-Open No. 2000-29069. In this method, a colored negative photosensitive resin film is formed, and this negative photosensitive resin film is patterned by back exposure and development using the array wiring of the array substrate as a mask, and the pixel electrode and the switching element are formed. A contact hole for conducting is formed. In this method, after the colored portion is formed, a step of removing a part of the colored portion provided on the array wiring by exposure and development later is required.
[0009]
Japanese Patent Laid-Open No. 2000-122072 discloses a method in which a contact hole is formed in a light shielding layer, and a pixel electrode and a switching element are connected through the contact hole. However, it is very difficult to provide a contact hole in the light-shielding layer, which has recently been markedly thinned by this method.
[0010]
In recent years, a method for manufacturing a color filter using an inkjet method has been actively studied. The method using the ink jet method has an advantage that the manufacturing process is simple and the cost is low.
[0011]
However, compared with methods such as the pigment dispersion method, in the ink jet method, the colored portion can be manufactured at a low cost by a simple process. However, in order to provide a contact hole in the colored portion, a separate contact hole is required after forming the colored portion. Is necessary.
[0012]
The object of the present invention is to develop a color filter manufacturing method using an inkjet method in a color filter on array, and to manufacture a liquid crystal element having a high aperture ratio and a bright color display characteristic at a low cost by a simple process. The object is to solve the problem and provide a highly reliable liquid crystal display element with high yield.
[0013]
[Means for Solving the Problems]
  Main departureTomorrow,Having a front side and a back sideSubstrateAnd on the surface side of the substrateScan signal line,Information signal line,Switching element,Pixel electrode to which a signal is applied via the switching element,Colored portion corresponding to the pixel electrodeHaveAn active matrix substrate;A substrate having a front surface and a back surface, and a surface side of the substrateCounter substrate having counter electrodeAnd a liquid crystal layer,
  The surface of the base of the active matrix substrate and the surface of the base of the counter substrateAnd facing each other,And the active matrix substrate and the counter substrate areA method for producing a liquid crystal element having a liquid crystal layer sandwiched therebetween,
  SaidActive matrix substrateHow to manufacture
  SaidSubstrateOn the surface ofMultiple scanning signal lines intersecting each otheras well asInformation signal line and intersection of scanning signal line and information signal lineInConnectiondidForming a switching element;
  A colored portion forming region for forming the colored portion; and a contact hole including a region where the switching element is exposed when viewed from the substrate surface side.OpeningMultiple providedPartition, On the surface of the substrate and the surface of the switching elementForming with a resin composition;
  SaidApertureIn the colored part formation areaInk applied by inkjet methodAnd a process of
  By curing the inkForming a colored portion;
  SaidThrough contact holeSaidSwitching elementAnd electricallyContinuityA pixel electrode to be formedProcess andIn this order,
  The contact hole is connected to the colored portion forming region when viewed from the surface side of the substrate,
  The ink is applied so as not to enter the contact hole by utilizing the surface tension of the ink.
  This is a method for manufacturing a liquid crystal element.
[0014]
  In the said invention, the following structure is included as a preferable aspect.The contact hole has a rectangular shape when viewed from the front surface side of the substrate, and is connected to the colored portion forming region at one side of the rectangle. The colored portion forming region has a rectangular shape when viewed from the front surface side of the substrate, and one side of the rectangular contact hole is connected to one side of the rectangular colored portion forming region. The rectangular connected to one side of the rectangular colored portionContact holeThe length of one side of the rectangleOf colored areasOurmostShort side lengthMust be 1/2 or less.SaidThe surface tension of the ink is 30 mN / m or more.The contact angle of the partition wall surface with pure water is 90 ° or more. SaidBulkheadBetween the step of forming the ink and the step of applying the ink, Increase the ink repellency of the partition wall surfaceforApply ink repellent treatmentHave stepsthing.SaidInk repellent treatment is performed in a gas atmosphere containing at least fluorine atoms.SaidPlasma on partition wallTheIrradiation plasma treatmentProcessBe.SaidThe gas introduced in the plasma treatment process is CF_Four, SF₆, CHF_Three, C₂F₆, C_ThreeF₈, C_FiveF₈At least one halogen gas selected from the group consisting ofSaidThe gas introduced in the plasma treatment process is CF_Four, SF₆, CHF_Three, C₂F₆, C_ThreeF₈, C_FiveF₈At least one halogen gas selected from₂It is a mixed gas with gas and O₂The mixing ratio is 30% or less.Forming the partition and thePlasma processing processBetweenA dry etching process is performed in which the substrate on which the partition walls are formed is irradiated with plasma in at least one gas atmosphere selected from oxygen, argon, and helium.Have stepsthing.SaidBulkheadButResin composition containing light-shielding agentConsist ofthing.SaidThe ink contains at least a colorant, a curing component, water, and an organic solvent.Between the step of forming the colored portion and the step of forming the pixel electrode, the pixel electrode, the planarization layer, and the colored portion are in this order when viewed from the substrate surface side.Form a planarization layerHave stepsthing.SaidThe planarization layerThe forming step is performed on the colored portion and in the contact hole.Photosensitive resinThe planarizing layer comprisingFormingAfterBy photolithographySaidContact holeInsideThe planarization layerBy wearingCreate a new contact holeIs a processthing.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a color filter-on-array liquid crystal device in which a partition wall filled with ink is formed on a substrate on which a switching element and a wiring are formed, and ink is applied to the opening portion of the partition wall by an ink-jet method to be colored. And forming a pixel electrode on the colored portion to form an active matrix substrate, and forming a narrow protrusion at the opening of the partition wall as a contact hole connecting the pixel electrode and the switching element. By providing a portion, when ink is applied to the opening portion, the surface tension of the ink prevents the ink from entering the convex portion, thereby forming a contact hole. The colored portion can be formed by filling the portion. That is, a contact hole is formed simultaneously with the formation of the colored portion, and the pixel electrode and the switching element can be easily conducted without going through a separate contact hole forming step.
[0018]
Hereinafter, the present invention will be described in detail with reference to embodiments.
[0019]
FIG. 1 is a schematic cross-sectional view of an embodiment of the liquid crystal element of the present invention. The liquid crystal element shown in this figure is a TN liquid crystal element using a TFT as a switching element. In the figure, 10 is an active matrix substrate, 20 is a counter substrate, and on the active matrix substrate 10 side, 1 is a base, 2 is a switching element provided on the base 1, and in this example is a TFT, Gate electrode, 12 gate insulating film, 13 semiconductor layers, 14 source electrode, and 15 drain electrode. In addition, 3 is a partition also serving as a light shielding layer, 7 is a colored portion of the color filter, 8 is a planarizing layer, 9 is a pixel electrode, and 16 is an alignment film. On the counter substrate 20 side, 21 is a substrate, 22 is a common electrode, and 23 is an alignment film. Reference numeral 18 denotes a liquid crystal layer sandwiched between the active matrix substrate 10 and the counter substrate 20, and the thickness thereof is held by the spacer 17. The active matrix substrate 10 includes a plurality of information signal lines (not shown) connected to the source electrode 14 of the TFT, which is the switching element 2, and a plurality of scanning signal lines (not shown) connected to the gate electrode 11, The pixels are formed so as to intersect with each other, and pixels are formed at the intersections.
[0020]
The partition wall 3 has a contact hole and a colored portion 7 for conducting the pixel electrode 9 and the switching element 2 in the opening.
[0021]
Hereinafter, the manufacturing process of the active matrix substrate which is characteristic in the manufacturing method of the liquid crystal element of the present invention will be described by taking the manufacturing process of the active matrix substrate 10 of the liquid crystal element shown in FIG. 1 as an example.
[0022]
FIG. 2 is a cross-sectional view schematically showing the process, in which 4 is an opening of the partition wall 3, 6 and 6 ′ are contact holes provided in the opening 4, and are the same members as in FIG. 1. Are given the same reference numerals. Moreover, (a)-(f) of FIG. 2 is a figure corresponding to the following process (a)-(f), respectively.
[0023]
Step (a)
First, the base body 1 is prepared. A glass substrate is generally used as the substrate 1, but for the purpose of constituting a liquid crystal element, a plastic substrate or the like can be used as long as it has necessary characteristics such as desired transparency and mechanical strength.
[0024]
The switching element 2 is formed on the substrate 1 by repeating general semiconductor thin film formation, insulating film formation, and etching by photolithography.
[0025]
Step (b)
A partition wall 3 having an opening 4 is formed on the substrate 1 on which the switching element 2 is formed using a resin composition. In the present invention, photosensitive resin such as epoxy resin, acrylic resin, polyimide resin including polyamideimide, urethane resin, polyester resin, and polyvinyl resin is used as the resin composition used to form the partition 3. However, it is preferable to have a heat resistance of 250 ° C. or higher, and from this point, an epoxy resin, an acrylic resin, and a polyimide resin are preferably used. A photolithography method is preferably used as the patterning method. As an exposure machine used for this photolithography, a proximity exposure apparatus is suitable. However, a mirror projection exposure apparatus may be used to improve the patterning accuracy. When a non-photosensitive material is used, it may be formed by patterning by wet or dry etching or lift-off using a photoresist as a mask.
[0026]
In the present invention, the partition wall 3 is preferably a light shielding layer in order to prevent abnormal operation of the switching element 2 and to improve color display characteristics by shielding light between adjacent colored portions 7. A black resin composition in which a light-shielding agent is dispersed in the composition is used. As a material characteristic after film formation, an electrical resistivity of 10¹²Those having Ω · cm or more, dielectric constant of 4 or less, and OD value of 2.5 or more are suitable.
[0027]
Further, the opening 4 of the partition wall 2 according to the present invention has a shape attached to the colored portion forming region as a projection and a contact hole 6 connecting the switching element 2 and the pixel electrode 9 in a planar shape parallel to the substrate 1. have. The colored portion forming region is a region at least overlapping with the pixel electrode 9 formed in a later step, and may be dot-shaped or striped as long as it can be filled with ink. Is a black matrix that shields the switching element 2 and the wiring from light. More preferably, a region that covers the gap between the adjacent pixel electrodes 9 and the switching element 2 is a light shielding region, and a region other than the region is a colored portion forming region.
[0028]
FIG. 3A shows an example of a planar shape of the opening 4 of the partition wall 3 according to the present invention parallel to the substrate 1. FIG. 3B shows a state where the ink 5 is applied to the opening 4 in the subsequent step (c).
[0029]
In the present invention, when the ink 5 is applied to the opening 4 of the partition wall 2 in a later step, the contact hole 6 is formed as a narrow convex portion attached to the colored portion forming region. Therefore, the colored portion 7 cannot be penetrated into the contact hole 6 and the colored portion 7 is formed only in the colored portion forming region. In the present invention, the width of the boundary portion between the contact hole 6 and the colored portion forming region is preferably as narrow as possible to prevent the ink 5 from entering the contact hole 6. Further, when the width of the narrowest portion of the boundary portion and the colored portion forming region is equal, the ink may enter the contact hole 6 or the ink may not be sufficiently dispersed in the colored portion forming region. is there. Therefore, the width of the boundary portion is narrower than the narrowest portion of the colored portion forming region, and preferably the width of the boundary portion is 1/2 or less of the width of the narrowest portion of the colored portion forming region. FIG. 4 shows an example of the shape of the opening 4 of the partition wall 3 according to the present invention. In the figure, a indicates the width of the narrowest portion of the colored portion forming region, and b indicates the width of the boundary portion between the contact hole 6 and the colored portion forming region.
[0030]
In the present invention, the shapes of the colored portion forming region and the contact hole 6 are not particularly limited. Therefore, the contact hole 6 is not limited to a rectangle, and there is no problem even if it expands outward in a trapezoidal shape as shown in FIGS. The colored portion forming region may be circular, square or striped as shown in FIGS. 4H and 4I.
[0031]
The partition wall 3 is preferably subjected to ink repellent treatment. The ink repellency treatment is not limited as long as the ink repellency on the upper surface of the partition wall 3 can be improved without impairing the ink repellency of the surface of the substrate 1 exposed in the opening 4. A silicone rubber layer is formed on the partition wall 3. Although there are a method and a method of applying an ink repellent treatment agent by a fluorine compound, a method of performing plasma irradiation in a gas atmosphere containing at least fluorine atoms is preferably used. By the plasma treatment, fluorine or a fluorine compound in the introduced gas enters the surface layer of the partition wall 3 and the ink repellency of the surface layer of the partition wall 3 is increased.
[0032]
The gas introduced at this step containing at least fluorine atoms is CF._Four, CHF_Three, C₂F₆, SF₆, C_ThreeF₈, C_FiveF₈It is preferable to use at least one halogen gas selected from In particular, C_FiveF₈(Octafluorocyclopentene) has zero ozone depletion ability and has an atmospheric lifetime (CF less than that of conventional gas)._Four: 50,000 years, C_FourF₈: 3200) 0.98, very short. Therefore, the global warming potential is 90 (CO₂= 100 years integrated value = 2) and (CF) compared with conventional gas_Four: 6500, C_FourF₈: 8700) Very small, extremely effective for protecting the ozone layer and the global environment, and desirable for use in the present invention.
[0033]
Further, as the introduced gas, a gas such as oxygen, argon, or helium may be used in combination as necessary. In the present invention, the CF_Four, CHF_Three, C₂F₆, SF₆, C_ThreeF₈, C_FiveF₈At least one halogen gas selected from₂When the mixed gas is used, the degree of ink repellency in this step can be controlled. However, in the mixed gas, O₂If the mixing ratio exceeds 30%, O₂Oxidation reaction due to becomes dominant and the effect of improving ink repellency is hindered.₂When the mixing ratio exceeds 30%, damage to the resin becomes significant.₂It is necessary to use in a range where the mixing ratio is 30% or less.
[0034]
As a method for generating plasma in this step, methods such as low-frequency discharge, high-frequency discharge, and microwave discharge can be used, and conditions such as pressure, gas flow rate, discharge frequency, and processing time during plasma irradiation are arbitrary. Can be set to
[0035]
The degree of ink repellency after the plasma treatment on the surface of the partition wall 3 according to the present invention is preferably such that the contact angle measured with pure water is 90 ° or more. If the contact angle is less than 90 °, color mixing tends to occur and a large amount of ink cannot be applied. Further, the ink enters the connection portion 6 through the partition wall 3.
[0036]
Further, if necessary, prior to the plasma treatment, dry etching treatment by plasma irradiation using at least one kind of introduced gas of oxygen, argon, and helium may be performed. By performing this dry etching treatment, contaminants attached to the surface of the substrate 3 in the step of forming the partition walls 3 are removed, and the surface is cleaned to improve the wettability (ink affinity) of the ink 5 in the subsequent step. The ink 5 can be diffused well in the opening 4. Furthermore, the dry etching process roughens the surface layer of the partition walls 3 and improves the ink repellency.
[0037]
The surface of the substrate 1 exposed in the opening 4 of the partition wall 3 according to the present invention desirably has ink affinity, and the contact angle measured with pure water is preferably 20 ° or less. By setting the contact angle with respect to pure water to 20 ° or less, the ink 5 can be satisfactorily spread and spread in the colored portion forming region in the opening 4, and even if the ink repellency on the surface of the partition wall 3 is high, white spots do not occur. . In particular, the angle is preferably 10 ° or less.
[0038]
Step (c)
Using an ink jet recording apparatus, R, G, and B inks 5 are applied into the openings 4 of the partition walls 3 from an ink jet head (not shown). In the present invention, as shown in FIG. 3B, the ink 5 applied in the opening 4 cannot enter the narrow contact hole 6 due to surface tension and remains in the colored portion forming region.
[0039]
As the ink jet 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. The ink 5 is a material containing a colorant of each color so as to form a colored portion 7 of R, G, B after curing, and preferably contains at least a colorant, a curing component, water, and a solvent. preferable. Hereinafter, the composition of the ink will be described in more detail.
[0040]
[1] Colorant
As the colorant to be contained in the ink in the present invention, both dyes and pigments can be used. However, when a pigment is used, it is necessary to add a separate dispersant in order to uniformly disperse in the ink. A dye-based colorant is preferably used because the ratio of the colorant in the total solid content becomes low. Moreover, it is preferable that it is the same amount or less as the addition amount of a coloring agent with the hardening component mentioned later.
[0041]
[2] Curing component
In consideration of process resistance, reliability, and the like in the subsequent step, it is preferable to contain a component that is cured by a heat treatment or light irradiation and immobilizes the colorant, that is, a crosslinkable monomer or polymer. In particular, it is preferable to use a curable resin composition in consideration of heat resistance in the subsequent process. Specifically, for example, as a base resin, acrylic resin having a functional group such as hydroxyl group, carboxyl group, alkoxy group, amide group, silicone resin; or cellulose derivatives such as hydroxypropylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, or These modified products; or vinyl polymers such as polyvinyl pyrrolidone, polyvinyl alcohol, and polyvinyl acetal. Furthermore, it is possible to use a crosslinking agent and a photoinitiator for curing these base resins by light irradiation or heat treatment. Specifically, melamine derivatives such as methylolated melamine are used as crosslinking agents, and dichromate, bisazide compounds, radical initiators, cationic initiators, anionic initiators, etc. are used as photoinitiators. Is possible. Moreover, these photoinitiators can also be used by mixing multiple types or combining with another sensitizer.
[0042]
[3] Solvent
As the ink medium used in the present invention, a mixed solvent of water and an organic solvent is preferably used. As water, it is preferable to use ion-exchanged water (deionized water) instead of general water containing various ions.
[0043]
Examples of the organic solvent include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, dimethylacetamide Amides such as acetone, ketones such as acetone and diacetone alcohol, or ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, and triethylene Alkylene glycols containing 2 to 4 carbons such as glycol, thiodiglycol, hexylene glycol, diethylene glycol, etc. Glycerins; Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether, diethylene glycol methyl ether, triethylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 2-pyrrolidone, etc. Is preferred.
[0044]
The surface tension of the ink thus adjusted is 30 mN / m (30 erg / cm²) Or more. If the surface tension of the ink is less than 30 mN / m, the ink 5 applied in the opening 4 of the partition wall 3 spreads over the entire surface of the opening 4 and the contact hole 6 cannot be formed. On the other hand, when the surface tension of the ink 5 is large, the ink 5 is provided as the contact hole 6 in the opening 4 because a force acts to minimize the surface area even if the ink 5 is applied in the opening 4. It does not enter a narrow area. For this reason, the surface tension of the ink 5 is preferably 30 mN / m or more, more preferably 45 mN / m or more.
[0045]
In addition to the above components, two or more kinds of organic solvents having different boiling points may be used in combination to obtain an ink having a desired physical property value, if necessary, or a surfactant, antifoaming agent, preservative. Etc. may be added.
[0046]
Step (d)
The colored portion 7 is formed in the colored portion forming region by performing necessary processing such as heat treatment and light irradiation, removing the solvent component in the ink 5 and curing it.
[0047]
Step (e)
If necessary, a planarizing layer 8 is formed on the colored portion 7. As the planarizing layer 8, a photocuring type, a thermosetting type, or a photothermal combination curing type resin material, or an inorganic film formed by vapor deposition, sputtering, or the like can be used. Any material that can withstand the formation process of the pixel electrode 9 and the formation process of the alignment film 16 can be used. When a resin material is used as the planarizing layer 8, photosensitive or non-photosensitive resin such as epoxy resin, acrylic resin, polyimide resin including polyamideimide, urethane resin, polyester resin, and polyvinyl resin. Although materials can be used, it is preferable to have heat resistance of 250 ° C. or higher, and from this point, epoxy resins, acrylic resins, and polyimide resins are preferably used.
[0048]
When a photosensitive material is used as the planarizing layer 8, a new contact hole 6 'is formed by piercing the planarizing layer embedded in the contact hole 6 by patterning by photolithography or the like. When a non-photosensitive material is used, it may be formed by patterning by wet or dry etching or lift-off using a photoresist as a mask. Alternatively, the contact hole 6 ′ may be formed by condensing light by the optical system using a laser and irradiating the planarizing layer 8.
[0049]
Step (f)
Finally, a transparent conductive film such as ITO is formed on the entire surface by sputtering, and then patterned by photolithography to form a pixel electrode 9 electrically connected to the switching element 2 through the contact hole 6 ′. Can do. Thereby, the active matrix substrate 10 having the color filter on array structure is manufactured.
The pixel electrode 9 may be formed directly on the colored portion 7 without using the planarizing layer 8, and an alignment film 16 made of polyimide or the like is formed on the pixel electrode 9 as necessary.
[0050]
The active matrix substrate 10 obtained in the above process, and the counter substrate 20 in which a common electrode 22 made of a transparent conductive film such as ITO and an alignment film 23 made of polyimide or the like are formed on a transparent base 21 such as a glass substrate, if necessary. Are opposed to each other through a spacer 17, the periphery is closed with a sealing material (not shown), and a liquid crystal layer 18 is formed by filling the gap with liquid crystal, whereby the liquid crystal element shown in FIG. 1 is obtained.
[0051]
In the above description, an example in which a TFT is used as the switching element 2 has been described. However, the present invention is not particularly limited to this. As the liquid crystal, a TN type is usually used, but the present invention is not particularly limited to this.
[0052]
【Example】
Example 1
[Formation of partition pattern]
In the same manner as a normal TFT formation process, film formation and patterning were repeated on a glass substrate having a thickness of 0.7 mm (“# 1737” manufactured by Corning) to form a TFT made of amorphous silicon.
[0053]
A photosensitive, carbon-free insulating black resin (manufactured by Fuji Hunt Technology Co., Ltd.) is applied on the glass substrate to a thickness of 2.0 μm using a spinner, and subjected to predetermined exposure, development, and post-baking treatment. Then, a black matrix pattern (partition) having an opening having a thickness of 2 μm and 75 μm × 225 μm and having the shape shown in FIG. 5A was formed to obtain an array substrate. In FIG. 5A, a = 60 μm, b = 10 μm, c = 75 μm, and e = 225 μm.
[0054]
[Ink adjustment]
Using an acrylic copolymer having the composition shown below as a thermosetting component, R, G, and B inks were prepared with the following compositions.
Curing component
50 parts by weight of methyl methacrylate
30 parts by weight of hydroxyethyl methacrylate
N-methylolacrylamide 20 parts by weight
[0055]
R ink
C. I. Acid Orange 148 3.5 parts by weight
C. I. Acid Red 289 0.5 parts by weight
20 parts by weight of diethylene glycol
20 parts by weight of ethylene glycol
50 parts by weight of ion exchange water
6 parts by weight of the above curing component
[0056]
G ink
C. I. Acid Yellow 23 2 parts by weight
2 parts by weight of zinc phthalocyanine sulfoamide
20 parts by weight of diethylene glycol
20 parts by weight of ethylene glycol
50 parts by weight of ion exchange water
6 parts by weight of the above curing component
[0057]
B ink
C. I. Direct Blue 199 4 parts by weight
20 parts by weight of diethylene glycol
20 parts by weight of ethylene glycol
50 parts by weight of ion exchange water
6 parts by weight of the above curing component
[0058]
The surface tension of the ink was 53.1 mN / m for R ink, 51.7 mN / m for G ink, and 54.1 mN / m for B ink.
[0059]
[Dry etching process]
The array substrate was subjected to plasma treatment under the following conditions using a cathode coupling parallel plate type plasma treatment apparatus.
[0060]
Gas used: O₂
Gas flow rate: 80sccm
Pressure: 8Pa
RF power: 150W
Processing time: 30 sec
[0061]
[Plasma treatment]
After the dry etching process, the array substrate was subjected to a plasma process under the following conditions in the same apparatus.
[0062]
Gas used: CF_Four
Gas flow rate: 80sccm
Pressure: 50Pa
RF power: 150W
Processing time: 30 sec
[0063]
[Evaluation of ink repellency]
Using an automatic liquid crystal glass cleaning / processing inspection device “LCD-400S” manufactured by Kyowa Interface Co., Ltd., the contact angle with respect to pure water was measured for the array substrate after the plasma processing. The black matrix surface was measured on a frame having a width of 5 mm provided around the fine pattern, and the glass substrate surface was measured at a location where no pattern on the outer side of the frame was provided. The contact angle for each pure water is 6 ° on the glass substrate surface.
Black matrix surface: 115 °
Met.
[0064]
(Preparation of colored part)
Using an ink jet recording apparatus equipped with an ink jet head having a discharge amount of 20 pl, 200 pl of the above R, G, B ink was applied to each black matrix opening of the above array substrate subjected to plasma treatment. . Next, heat treatment was performed at 90 ° C. for 10 minutes and subsequently at 230 ° C. for 30 minutes to cure the ink to form a colored portion, and a color filter on array substrate was produced.
[0065]
[Formation of planarization layer and pixel electrode]
After that, an acrylic photosensitive type resin was applied on the color filter on array substrate to form a planarization layer, and then the contact hole formed in the opening of the black matrix was filled by photolithography. A new contact hole was formed in the planarization layer. Finally, a transparent electrode was formed on the entire surface by ITO sputtering, and then a pixel electrode was patterned by photolithography, thereby forming a pixel electrode that was electrically connected to the TFT through the new contact hole. Thus, an active matrix substrate having a color filter on array structure was obtained.
[0066]
[Production of liquid crystal element]
A polyimide alignment film material (“AL-1051” manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied to the entire surface of the active matrix substrate by 50 nm, and a rubbing treatment was performed to form an alignment film.
[0067]
Next, an alignment film material similar to the above is applied on the common electrode of the counter substrate made of a 0.7 mm thick glass substrate ("# 1737" manufactured by Corning) on which a predetermined common electrode (ITO film) is formed. After the formation, rubbing treatment was performed to form an alignment film. Thereafter, an adhesive was printed along the periphery of the alignment film on the substrate except for the liquid crystal injection port, and a silver paste electrode transition material was formed on the electrode transition electrode around the adhesive.
[0068]
The active matrix substrate and the counter substrate were arranged through a spherical spacer so that the alignment films face each other and the respective rubbing directions were 90 °, and the adhesive was cured by heating and bonded.
[0069]
A liquid crystal layer is prepared by injecting 0.1 wt% of a chiral agent “S811” into a liquid crystal composition (“ZLI1565” manufactured by E. Merck) from a liquid crystal injection port by a normal method. Sealed with a cured resin.
[0070]
The color display active matrix drive type liquid crystal element manufactured in this way is a reliable liquid crystal element capable of forming contact holes uniformly in the surface, having a high aperture ratio and high display performance.
[0071]
(Example 2)
The opening of the black matrix is the opening shape shown in FIG. 5B (a = 75 μm, b = 10 μm, d = 10 μm, e = 225 μm), and is the same as in Example 1 except that the dry etching process was not performed. A liquid crystal element was produced.
[0072]
For the array substrate after the plasma treatment, the contact angle with respect to pure water was measured in the same manner as in Example 1.
Glass substrate surface: 10 °
Black matrix surface: 105 °
Met. Although the ink repellency on the surface of the black matrix was lowered, even when ink was applied to the opening, the ink did not spread in the contact hole, and a uniform contact hole could be formed in the surface.
[0073]
(Example 3)
After forming the colored portion in the same manner as in Example 1, a transparent electrode is formed on the entire surface by ITO sputtering without forming a planarizing layer, and the pixel electrode is patterned by photolithography, so that the TFT is electrically connected via the contact hole. Pixel electrodes that are electrically conductive are formed.
[0074]
Next, a negative transparent photosensitive resin (“NN-500” manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the pixel electrode. The film thickness of the photosensitive resin layer is expected to be a shrinkage amount in which the film thickness is shrunk in a baking process for the purpose of increasing the film hardness of the subsequent process in order to make the interval between the liquid crystal cells for display 5 μm thick, for example. Was applied at a film thickness of 5.4 μm. After that, by using a photomask to irradiate the photosensitive resin with ultraviolet rays in advance according to the cross-shaped alignment marks formed outside the effective pixel region on the active matrix substrate, the development process is performed with an alkali developer. The unexposed portions were dissolved to form columnar photolitho spacers at predetermined positions on the black matrix irradiated with ultraviolet rays.
[0075]
The substrate on which the photolitho spacer was formed was baked at a temperature of 200 ° C., so that the columnar photolitho spacer was thermally cured to have a function as a spacer having a thickness of 5 μm. Hereinafter, a liquid crystal element was produced in the same manner as in Example 1 except that a spherical spacer was not used.
[0076]
In this example, a planarizing layer was not used, but a reliable liquid crystal element with high display performance could be obtained.
[0077]
Example 4
A black matrix was formed in the same manner as in Example 1 except that post-baking was not performed. When post-baking is performed, the glass substrate surface exposed at the opening of the black matrix is contaminated with organic substances, and the ink is difficult to spread. Therefore, a colored portion was formed after the development of the black matrix.
[0078]
The contact angles of the black matrix and the glass substrate surface with respect to pure water before forming the colored portion are as follows.
Glass substrate surface: 10 °
Black matrix surface: 70 °
[0079]
Since the contact angle with pure water on the surface of the black matrix was small, the margin for color mixing was small, but after forming the colored portion by ink jet, the ink did not spread in the contact hole, and the contact hole could be formed.
[0080]
(Comparative Example 1)
A color filter-on-array substrate was produced in the same manner as in Example 1 except that the opening of the black matrix was changed to the opening shape shown in FIG. 5C (a = 75 μm, e = 225 μm). However, after forming the colored portion by inkjet, all the openings of the black matrix are filled with ink, and a contact hole cannot be formed.
[0081]
【The invention's effect】
As described above, according to the present invention, by forming a region in which the ink cannot penetrate into the opening due to the surface tension of the ink, a colored portion is formed in the opening of the partition wall using the inkjet method, and at the same time, the contact hole is formed. Thus, the pixel electrode and the switching element can be easily conducted. Therefore, it is possible to easily provide a color filter-on-array structure with contact holes, and simultaneously realize a high aperture ratio and rationalization of the manufacturing process, thereby reducing the cost of an active matrix drive type liquid crystal device with excellent color display characteristics. It becomes possible to provide.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an embodiment of a liquid crystal element of the present invention.
2 is a schematic cross-sectional view showing a manufacturing process of the active matrix substrate of the liquid crystal element shown in FIG. 1. FIG.
FIG. 3 is a schematic plan view showing an example of an opening shape of a partition wall in the manufacturing method of the present invention.
FIG. 4 is a schematic plan view showing another example of the shape of the opening of the partition wall in the manufacturing method of the present invention.
FIG. 5 is a schematic plan view showing an opening shape of a partition wall in an example of the present invention.
[Explanation of symbols]
1,21 Base
2 TFT
3 Bulkhead
4 openings
5 Ink
6, 6 'contact hole
7 Coloring part
8 Planarization layer
9 Pixel electrode
10 Active matrix substrate
11 Gate electrode
12 Gate insulation film
13 Semiconductor layer
14 Source electrode
15 Drain electrode
16, 23 Alignment film
17 Spacer
18 Liquid crystal layer
20 Counter electrode
22 Common electrode

Claims (15)

Front and back and the scanning signal line on the surface side of the substrate and said substrate having the information signal line, an active having a switching element, a pixel electrode to which a signal is applied via the switching element, the colored portion corresponding to the pixel electrode A matrix substrate, a substrate having a front surface and a back surface , a counter substrate having a counter electrode on the surface side of the substrate, and a liquid crystal layer,
A method of manufacturing a liquid crystal element in which the surface of the base of the active matrix substrate and the surface of the base of the counter substrate are arranged to face each other, and the active matrix substrate and the counter substrate sandwich a liquid crystal layer,
Method for producing the active matrix substrate,
Forming a plurality of scanning signal lines and information signal lines which cross each other on the surface of the substrate, and a switching element connected to the intersection between the scanning signal lines and information signal lines,
A partition wall provided with a plurality of openings having a colored portion forming region for forming the colored portion and a contact hole including a region where the switching element is exposed when viewed from the substrate surface side , A step of forming a resin composition on the surface and the surface of the switching element ;
A step of applying an ink by an inkjet method in the colored portion-forming region of the opening,
Forming a colored portion by curing the ink ;
And a step of forming a pixel electrode which conducts the switched elements electrically via the contact hole in this order,
The contact hole is connected to the colored portion forming region when viewed from the surface side of the substrate,
The method of manufacturing a liquid crystal element, wherein the ink is applied so as not to enter the contact hole by utilizing a surface tension of the ink . 2. The liquid crystal device according to claim 1, wherein the contact hole has a rectangular shape when viewed from the front surface side of the substrate, and is connected to the colored portion forming region at one side of the rectangle. Method. The colored portion forming region has a rectangular shape when viewed from the surface side of the substrate, and one side of the rectangular contact hole is connected to one side of the rectangular colored portion forming region. The manufacturing method of the liquid crystal element of 2. The length of one side of the rectangular contact hole connected to one side of the rectangular colored portion is ½ or less of the length of the shortest side of the rectangular colored portion forming region. Item 4. A method for producing a liquid crystal element according to Item 3. The method for producing a liquid crystal element according to claim 1, wherein the ink has a surface tension of 30 mN / m or more. The method for producing a liquid crystal element according to claim 1, wherein a contact angle of the partition wall surface with respect to pure water is 90 ° or more. Between the step of applying the ink and the step of forming the partition wall, according to claim 1 including the step of applying an ink repellent treatment in order to improve the ink repellency of the partition wall surface Liquid crystal element manufacturing method. The ink repellent treatment is a method of manufacturing a liquid crystal device according to claim 7, which is a plasma treatment process of irradiating plasma on the partition wall in a gas atmosphere containing at least fluorine atom. Gas introduced in the plasma processing step, according to the _{CF 4, SF 6, CHF 3} , C 2 F 6, C 3 F 8, C 5 claim 8 is at least one halogen gas selected from F ₈ Liquid crystal element manufacturing method. The gas introduced in the plasma treatment step is a mixture of at least one halogen gas selected from CF ₄ , SF ₆ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , and C ₅ F ₈ and O ₂ gas. The method for producing a liquid crystal element according to claim 8 , wherein the gas is a gas and the mixing ratio of O ₂ is 30% or less. A step of performing a dry etching process of irradiating the substrate on which the partition wall is formed with plasma in at least one gas atmosphere selected from oxygen, argon, and helium between the step of forming the partition wall and the plasma treatment process The manufacturing method of the liquid crystal element of any one of Claims 8-10 which have these . The method for producing a liquid crystal element according to claim 1, wherein the partition wall is made of a resin composition containing a light shielding agent. The method for producing a liquid crystal element according to claim 1, wherein the ink contains at least a colorant, a curing component, water, and an organic solvent. A flattening layer is formed between the step of forming the colored portion and the step of forming the pixel electrode so that the pixel electrode, the flattened layer, and the colored portion are in this order when viewed from the substrate surface side. The manufacturing method of the liquid crystal element of any one of Claims 1-13 which has the process to do . The step of forming the planarizing layer is formed by forming the planarization layer made of a photosensitive resin in the colored portion and on the contact hole, the drilled the planarization layer in the contact hole by photolithography The method for manufacturing a liquid crystal element according to claim 14 , wherein the process is a step of forming a new contact hole.

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