Patent Application
20070287788
In this description, the term “light” includes all visible or invisible light which may initiate photoreaction of a photoreactive functional group, mainly including ultraviolet, infrared, electron beam etc.
The repair ink of this invention is applicable for repairing a micro defect of a fine colored pattern. The repair ink comprises a pigment, a monomer having a reactive functional group, an additive, and a solvent. In this embodiment, the viscosity of the repair ink is about 40˜350 mPa·sec. In addition, the weight percentage of the solvent in the repair ink is about 20˜60. Each component will be described in detail hereinafter.
In this embodiment, the pigment is produced by Taiwan Nano Technology Corp. Preferably, various organic and inorganic pigments is selected depending on the color of the picture element to be corrected. Specific examples of these organic pigments may be listed in the Color Index(C.I., Issued by the Society of Dyers and Colourists Corp.) and be classified as compound of pigment, for example, the following color index (C.I.)numbers: yellow pigments, such as C.I. Pigment Yellow 1, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 83, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 150, C.I. Pigment Yellow 180, and C.I. Pigment Yellow 185 and the like; red pigments, such as C.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 177, and C.I. Pigment Red 254, and the like; blue pigments, such as C.I. Pigment Blue 15, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, and C.I. Pigment Blue 15:6, and the like; green pigments, such as C.I. Pigment Green 7, and C.I. Pigment Green 36, and the like; purple pigments, such as C.I. Pigment Purple 23, and C.I. Pigment Purple 23:19 and the like.
Also, the a forementioned inorganic pigments comprises titanium oxide, barium sulfate, calcium carbonate, zinc white, lead sulfate, yellow lead, red oxide(red ferric iron), cadmium red, ultramarine blue, Prussian blue, chrome oxide green, cobalt green, ocher, titanium black, synthetic iron black, and carbon black and the like. In the invention, the pigments may be used alone or in a mixture of two or more pigments and are not limited to those as mentioned above.
The weight percentage of the pigment in repair ink is about 1˜45, especially preferably 5˜30, and most preferably 9˜25.
In the invention, carbon black may be used in the black repair ink for correcting a defect of a black matrix to achieve higher masking ability. The weight percentage of the carbon black in the repair ink is about 5˜45, especially preferably 5˜30, still most preferably 9˜25. In addition, when the pigment is carbon black, the repair ink further comprises a photoreaction initiator.
The monomer having a reactive functional group in the repair ink plays multiple roles therein:
I. The monomer having a reactive functional group can act as a adhesive. Through adjustment of types and proportion of the monomer having a reactive functional group and the solvent, physical properties such as viscosity and coating property can be properly adjusted to an applicable range.
II. Various types and proportions of the monomer having a reactive functional group can improve the solvent resistance or the heat resistance of the repaired part as well as hardenable film-forming property after coating.
III. Appropriate color saturation and adhesion to a substrate may be achieved by adequately adjusting components and proportion of the pigment and the monomer having a reactive functional group.
IV. The monomer having a reactive functional group is the composing unit for the polymerization reaction.
In the invention, the monomer structure has more than two reactive functional groups or can be an oligomer and possesses good fluidity under normal temperature. Moreover, in addition to adjusting viscosity, coating film-forming property and the like, more importantly, the monomer structure may participate in polymerization cross-link-hardened film forming.
Preferably, when a multifunctional reactive monomer with more than two reactive functional groups in one molecule is used alone or in a mixture of more than two monomers, a sufficient hardening property will be displayed due to higher cross linking density.
The reaction form of the reactive functional groups should be a hardening reaction, such as free radical polymerization, cation polymerization, and anion polymerization. Specifically, a monomer having an ethylene unsaturated bond is preferred for the reactive monomer, which may be excited by the initiator to cause thermal free radical polymerization or directly initiate photo-radical polymerization after being exposed to light. When the reactive functional group of the monomer contains epoxy group, heat hardening and photo cationic polymerization can be applied.
Monomers having an ethylene unsaturated bond are, for example, acrylate monomers having a multifunctional group, such as dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol methacrylate, diallyl phthalate, tripropylene glycol dimethacrylate, neopentyl glycol dimethacrylate-epoxypropane adduct, ethylene glycol methacrylate, diethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, hexyl dimethacrylate, neopentyl glycol dimethacrylate, glyceryl dimethacrylate, glyceryl trimethacrylate, glyceryl tetramethacrylate, butanetrimethylolpropane trimethacrylate,1,4-butanediol diacrylate, and the like. Among these, dipentaerythritol hexaacrylate, dipentaerythritol pentamethacrylate, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate are preferred due to higher cross linking density and sufficient hardening property, thus are preferred embodiments.
In the invention, there is no special limit on the type of the solvent to be used. Those solvents in which a pigment is well dispersed and a monomer having a reactive functional group is well dissolved are preferred. In addition, more than two solvents may also be applied at the same time.
Examples of solvents are alcoholic solvents such as methanol, ethanol, n-propanol, and isopropanol etc; cellosolve solvents such as methoxyethanol and ethoxyethanol etc; carbitol solvents such as methoxyethoxyethanol and ethoxyethoxyethanol etc; ester solvents such as ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, and ethyl lactate etc; ketone solvents such as acetone, methyl isopropyl acetone, and cyclohexanone etc; cellosolve acetate solvents such as methoxyethyl-acetate, ethoxyethyl acetate and, ethyl cellosolve acetate etc; acetate solvents such as methoxyethoxyethyl acetate, and ethoxyethoxyethyl acetate etc; ether solvents such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetrahydrofuran, etc; amide solvents such as N,N-dimethylformnamide, N,N-dimethylacetamide and N-methylpyrrolidone, etc; lactone solvents such as γ-butyrolactone, etc; unsaturated hydrocarbon solvents such as benzene, toluene, xylene and naphthalene, etc; non-aqueous organic solvents such as n-pentane, n-hexane, n-octane, etc. Among others, the preferred solvents are cellosolve acetate solvents such as methoxyethyl acetate, ethyoxyethyl acetate and ethyl cellosolve acetate, etc; carbitol acetate solvents such as methoxyethoxyethyl acetate and ethoxyethoxyethyl acetate, etc; ether solvents such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and propylene glycol diethyl ether, etc; ester solvents such as methyl methoxypropionate and ethyl ethoxypropionate, etc. Especially preferred are: PGMEA(propylene glycol monomethyl ether acetate, Ch3OCH2Ch(Ch3)OCOCH3), MBA(acetic acid-3-methoxybutyl ester CH3CH(OCH3)CH2CH2OCOCH3), DMDG(diethylene glycol dimethyl ether, H3COC2H4OCH3), or mixtures thereof.
The weight percentage of the solvent in the repair ink is about 20˜60, especially preferably 25˜55, and more preferably 27˜45.
In this embodiment, the repair ink further comprises a pigment dispersant. Also, the use of the pigment dispersant is to improve the dispersion stability of the pigment. The weight percentage of the pigment in the repair ink is about 0.01˜25, especially preferably 0.05˜15, and most preferably 0.1˜10. Specific examples of the pigment dispersant include alkyl amide compounds such as nonanamide, decyl amide, lauryl amide, n-dodecyl cetanyl amide, n-heptadecyl propionamide, N,N-dimethyl lauryl amide, N,N-dihexylacetamide etc; amine compounds such as diethylamine, diheptyl amine, dibutyl cetanyl amine, N,N,N′,N′-tetramethyl methylamine, triethylamine, tributyl amine and trioctylamine etc; amino compounds having hydroxy group such as monoethanolamine, ethanolamine, triethanolamine, N,N,N′,N′-(tetrahydroxyethyl)-1,2-diaminoethane, N,N,N′-tri(hydroxyethyl)-1,2-diaminoethane, N,N,N′,N′-tetra(hydroxyethyl polyhydroxyethylene)- 1,2-diaminoethane, 1,4-bis(2-hydroxyethyl)piperazine and 1-(2-hydroxyethyl)piperazine etc; hexahydronipecotamide, hexahydroisonipecotamide, nicotinamide etc; and others, for example, polycarboxylates such as polyurethane and polyacrylate etc; polyester pigment dispersants with high molecular weight such as unsaturated polyamide, polycarboxylic acid(part)amine salt, ammonium salt of polycarboxylic acid, polycarboxylic acid alkylamine salt, polysiloxane, long-chain polyaminoamide phosphate, modified polycarboxylate containing hydroxy group, amide, and salt formed from reaction of poly(lower alkylene imine) and polyester with free carboxyl. In terms of superior dispersibility at higher colored concentration, polyester pigment dispersants with high molecular weight are preferred.
In this embodiment, the repair ink may further comprise a polymerization initiator. Also, the purpose of adding the polymerization initiator is to improve the reactivity and film-forming hardening rate of a monomer having a reactive functional group. When a monomer having an ethylene functional group is applied, a free radical initiator is usually added. The free radical polymerization initiator may include, for example, acetophenones, diphenylketones, ketals, anthraquinones, 9-thioxanthones, azocompounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoroamine compounds, etc. Specific examples include 1-hydroxy-cyclohexyl-phenyl-one, 2-methyl-1-(4-(thiomethyl)phenyl)-2-morpholinopropan-1-one, benzyl dimethyl ketone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-penylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, diphenylketone, etc. Among the above, acetophenones, and 9-thioxanthone compound initiator, specifically, 2-benzyl-2-dimethylamino-1-(4-morhpolinophenyl)-butan-1,2-methyl-1-(4-thiomethylphenyl)2-morpholino-propan- 1-one and diethyl-9-oxodibenzthiopyrane are preferred. The initiators can be used alone or in a combination of more than one initiator.
In this embodiment, the additive is a surfactant, which is used to decrease the surface tension of solution while increase the surface smoothness and evenness. Surfactants usually are polysiloxane, modified polysiloxane, polyether-modified polysiloxane and polyester-modified polysiloxane etc; polyacrylate, polyacrylate copolymer, fluorine-modified polyacrylate copolymer etc; or solvents with high boiling point containing surfactant etc.
In this embodiment, the viscosity of the repair ink is about 40˜350 mPa·Sec, preferably 50˜250 mPa·Sec, and most preferably 60˜100 mPa·Sec. If the viscosity of the repair ink is too low, the coated spot is easy to infiltrate and spread after coating, resulting in a defect of color mixture. On the contrary, if the viscosity of the repair ink is too high, the film of the coated spot will be thicker and the color will be deeper, and it's difficult to obtain a smooth surface for the coated spot and a relatively high protrusion will be formed. Thus, if the viscosity of the repair ink is set within the above range, the coated spot will be smooth and no infiltration will be caused, and further, the height of the protrusion will fall within an allowable range.
In addition, when a black repair ink is applied and the film thickness of the hardened black repair ink is 1.9 μm, the optical density is above 3.0, preferably 3.2, and especially preferably 3.4. The defect part corrected by using this black repair ink will not be too obvious, and a good masking effect will be obtained. The manufacturing method of the repair ink according to the invention is described below.
The manufacturing method of the repair ink according to the invention includes the following steps: firstly, providing a pigment, a monomer having a reactive functional group, an additive, and a solvent; then, the pigment, the monomer having a reactive functional group, the additive, and the solvent are mixed to produce the repair ink. The above materials may be added in any order with mixing to achieve proper dispersion.
In addition, in the manufacturing of a black repair ink, the pigment is carbon black. The pigment, a monomer having a reactive functional group, an additive, a solvent, and a photoreaction initiator are mixed to produce the repair ink.
The main use of the repair ink of this invention is to correct a defect of a color filter. However, if desired, the ink may be optionally varied to perform the same correcting effect on defects of other fine colored patterns. In terms of correcting a color filter substrate, correcting on a black matrix may be carried out once it is formed. Alternatively, after any color in the color filter layer is formed, correcting may be carried out on the corresponding color. The correcting may also be carried out together after the black matrix and the color filter layer are completely formed. However, if the correcting is carried out only after a protection layer or a transparent conductive layer is formed, the protection film and transparent conductive layer on the repaired site will be damaged. Thus it is recommended that corrections be made before the protection film or transparent conductive layer is formed.
After the repair ink is coated on the defect part, high temperature heating may be applied to initiate the cross link-hardened film forming of the monomer, since the monomer having a reactive functional group in the repair ink has an ethylene non-saturated bond. Thus, after the defect part is corrected, if the coated portion is made smooth by using a protection layer and a transparent conductive layer, the color filter will have equivalent performance as that of a non-defect product. Considering the balance with colored concentration, the height difference advantageously is −3 μm-+5 μm, especially preferably −2 μm-+3 μm, and more preferably −1 μm-+2 μm.
The invention is illustrated below with reference to A series and B series embodiments, in which the A series embodiment is intended to demonstrate the advantages of the repair ink of this invention while the B series embodiment is directed to black repair ink.
(1) Pigment dispersions in well-dispersed phase, provided directly by Taiwan Nano Technology Corp., respectively are Manufacturing example A1, Manufacturing example A2 and Manufacturing example A3, as shown in Table A1.
(2) According to the proportions as shown in table A2, the pigments of Manufacturing example A1, Manufacturing example A2 and Manufacturing example A3 etc, provided by Taiwan Nano Technology Corp. are in one portion mixed with a monomer having a reactive functional group, a solvent, and an additive. Viscosity is measured by a viscometer and if necessary, additional portion of the solvent may be used to adjust the viscosity. Components of the resulted repair ink are shown in Table A2.
The assessment of related physical properties is carried out on the above embodiments A1 to A3.
I. Measurement and Assessment of Height Difference at the Repaired Part.
The measurement of height difference at the repaired part is based on the film thickness measured by a stylus measuring apparatus. The so-called height difference refers to the height difference between the repaired part and the surrounding part. If the height difference is above 3 μm, then the correcting on the color filter substrate is not good. Thus, it is determined to be bad.
II. Visual Assessment of the Repaired Part.
The corrected color filter substrate is put on a backlight to observe the repaired part for determining whether it is acceptable. If it is obviously found that as the repair ink flows, an overly large corrected area or too thin color occurs at the repaired part, it is determined to be bad.
III. Reliability Test on the Repaired Part.
A color filter substrate with the repaired part covered with a transparent conductive layer is respectively put into isopropanol(RT 25° C./30 mins), ethanol(RT 25° C./30 mins), and N-methyl pyrrolidinone(RT 45° C./1 min/3 cycles) solution etc.. Microscope observation is carried out after washing and drying. If there is no abnormal status such as peeling off or chapping, it is acceptable.
The results of viscosity, solids concentration, pigment concentration in solids, concentration of adhesive, measurement of protrusion height, visual assessment of the corrected part, and drug tolerance testing for embodiments A1-A3 are shown in Table A4.
As seen from the above results, in relative embodiment A1-A3, the coating property on the repaired part is good and the visual appearance, protrusion height and reliability test after correcting and hardening are all fine.
The following is directed to the black repair ink, i.e., B series embodiment.
(1) Black pigment dispersion in a well-dispersed phase, provided directly by Taiwan Nano Technology Corp. is manufacturing example B1, as shown in Table B1.
(2) According to the proportion in table B2, the pigment of Manufacturing example B1 provided by Taiwan Nano Technology Corp. is in one portion well mixed with a monomer having a reactive functional group, a solvent, an additive and a photoreaction initiator. Viscosity is measured by a viscometer and if necessary, additional portion of the solvent may be added to adjust the viscosity. Components of the resulted repair ink are shown in Table B2.
The assessment of related physical properties is carried out on the above embodiment B1.
I. Measurement and Assessment of Height Difference at the Repaired Part.
The measurement of height difference at the repaired part is based on the film thickness measured by a stylus measuring apparatus. The so-called height difference refers to the height difference between the repaired part and the surrounding part. If the height difference is above 3 μm, then the correcting on the color filter substrate is not good. Thus, it is determined to be bad.
II. Visual Assessment of the Repaired Part.
The corrected color filter substrate is put on a backlight to observe the repaired part for determining whether it is acceptable. If it is obviously found that as the repair ink flows, an overly large corrected area or too thin color occurs at the repaired part, it is determined to be bad.
III. Reliability Test on the Repaired Part.
A color filter substrate with the repaired part covered with a transparent conductive layer is respectively put into isopropanol(RT 25° C./30 mins), ethanol(RT 25° C./30 mins), and N-methyl pyrrolidinone(RT 45° C./1 min/3 cycles) solution etc.. Microscope observation is carried out after washing and drying. If there is no abnormal status such as peeling off or chapping, it is acceptable.
The results of viscosity, solids concentration, pigment concentration in solids, concentration of adhesive, measurement of protrusion height, visual assessment of the corrected part, and drug tolerance testing for the above embodiment B1 are shown in Table B4.
As seen from the above results, in relative embodiment B1, the coating property on the repaired part is good and the visual appearance, protrusion height, and reliability test after correcting and hardening are all fine.
To further illustrate difference between prior art and this invention, the comparisons of components, manufacturing method, and usage of repair ink are carried out below.
To sum up, the repair ink and manufacturing method thereof according to the invention at least has the following advantages.
I. The repair ink of this invention at least contains a pigment, a monomer having a reactive functional group, an additive, and a solvent. When manufacturing, there is no need to prepare various solutions respectively and then mix them together; but directly put the above materials in a single container in order to produce the repair ink with proper properties such as viscosity by adequately stirring them into an even dispersed phase.
II. As compared with black repair ink made of red, yellow, and blue pigments in prior art, carbon black is used as a pigment component of repair ink in this invention. When the film thickness is 1.9 μm, the optical density may be above 3.0 and such a defect part may be substantially masked after repairing.
III. Only heat is needed when the red, green, and blue repair ink of the invention is coated on a defect part, so that a monomer having a reactive functional group may perform a cross-linking reaction to completely harden. If the above black repair ink made of carbon black is applied, light irradiation is still needed after coating so that the surface of the repaired part may instantly harden once. Then, the high temperature curing may be carried out on the repaired part.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.
