Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
  • G02F1/13378—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation
  • G02F1/133784—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation by rubbing
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D15/00—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used
  • D03D15/20—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads
  • D03D15/208—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads cellulose-based
  • D03D15/225—Woven fabrics characterised by the material, structure or properties of the fibres, filaments, yarns, threads or other warp or weft elements used characterised by the material of the fibres or filaments constituting the yarns or threads cellulose-based artificial, e.g. viscose
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D27/00—Woven pile fabrics
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2201/00—Cellulose-based fibres, e.g. vegetable fibres
  • D10B2201/20—Cellulose-derived artificial fibres
  • D10B2201/28—Cellulose esters or ethers, e.g. cellulose acetate

Definitions

• the present invention relates to a rubbing cloth for a liquid crystal dsplay device on which finely aligned grooves may be formed to align liquid crystals on the glass substrate of a liqid crystal dsplay device, thereby being capable of solving such problems as scratch, non-uniform rubbing, etc., and a manufacturing method thereof.
• a substrate on which an alignment film has been formed passes through a rubbing process to obtain uniform liquid crystal molecules.
• the rubbing process is performed by rolling a rubbing cloth made of rayon or nylon around a roller and contacting the roller with an alignment film, so that the alignment film is rubbed to form alignment grooves offering a certain degree of uni- drectional alignment and a pretilt angle within a certain range.
• the alignment film is formed b rrality of lift pins are located on the stage to load or unload the substrate.
• the rubbing roller moves to contact the top o f the substrate while rotating. And, alignment grooves are formed on the alignment film of the substrate due to rubbing by the rubbing roller. Disclosure of Invention Technical Problem
• the success of the rubbing process is determined by rubbing time, rubbing depth, rotation number of the roller, radus of the roller, moving speed of the stage, etc. These process conditions are set by the liquid crystal dsplay device manufacturers and cannot be easily changed. Therefore, important changeable factors in the rubbing process are length, strength, thickness, density, etc. of the rubbing cloth pile.
• the conventional pile yarn of a rubbing cloth is mostly made of rayon, the strength is so high that scratches tend to occur if the rubbing strength is non-uniform.
• a change of the thickness of the rayon yarn is limited and improvement of the pile density is also limited, it is dfficult to form finely aligned grooves.
• rayon is unstable when contacted with water, the manufacturing process tends to be complex and costly.
• the present invention provides a rubbing cloth for a liquid crystal dsplay device comprising a textile of wa ⁇ and weft and a pile yarn aligned with an inclination along the drection of the warp or weft, wherein the pile yarn is a modfied cellulose acetate filament fiber in which 10 to 50% of all acetyl groups are substituted by hydroxy groups.
• the present invention also provides a manufacturing method of a rubbing cloth for a liqid crystal dsplay device comprising the steps of:
• the present invention fiirther comprises a liqid crystal dsplay device man- ufactured using the rubbing cloth.
• a fiber may have rayon characteristics at the outer layer and acetate characteristics at the inner layer
• the present inventors found that finely aligned grooves can be formed in the rubbing process and that such problems as scratch, non-uniform rubbing, etc. may be solved if a plurality of cellulose acetate filaments are woven using a pile yarn of a rubbing cloth for a liqid crystal dsplay device and modfying the surface of the cellulose acetate filaments with an alkali.
• the rubbing cloth of the present invention is manufactured by weaving a plurality of cellulose acetate filaments in between two textiles of warp and weft along the warp drection as pile yarn, modfying the surface of the cellulose acetate filaments with an alkali and aligning the pile yarn along the drection of the warp or weft with an inclination in parallel, so that a uniform dstribution is obtained.
• the rubbing cloth of the present invention is woven along a drection increasing the pile density, so that fine alignment grooves may be formed.
• a viscous rayon filament or a cupraammonium rayon filament in the range of 50 to 200 deniers is preferably used for the textile (ground textile).
• a cellulose acetate filament in the range of 50 to 240 deniers is used for the pile yarn.
• the cellulose acetate filament fiber has a degree of substitution of 2.0 to 2.75. 2
• the pile yarn has a filament density of at least 24,000 per 1 cm .
• the pile yarn woven in between the two textiles is cut so that the pile length becomes 1.4 to 2.1 mm.
• the alkali is used at 5 to 20 wt% per 100 wt% of the acetate fiber after the pile has been cut. If the content of the alkali is below 5 wt%, the outer layer of the fiber cbes not have rayon characteristics, so that formation of alignment grooves for a liqid crystal dsplay device becomes dfficult due to static electricity, low fiber strength, etc. Otherwise, if it exceeds 20 wt%, even the inner layer has rayon characteristics, and thus there is no problem of static electricity, low fiber strength, etc., but stability in water worsens so it is dfficult to obtain a uniform pile. Ibr the alkali, it is preferable to use an aqieous alkali solution alone or a reaction solution obtained by mixing an aqieous alkali solution with a reaction aid.
• the cellulose acetate filament fiber has a degree of saponification ranging from 10 to 50%. That is, an acetate fiber having a degree of substitution ranging from 2.0 to 2.75 is modfied with an alkali, so that 10 to 50%, preferably 20 to 40%, of all acetyl groups of the acetate are saponified by hydroxy groups. Resultantly, the acetate fiber has a degree of substitution ranging from 1.27 to 1.91.
• the degree of saponification of the acetate fiber is below 10%, the outer layer of the fiber cbes not have rayon characteristics, so that formation of alignment grooves of a liqid crystal dsplay device becomes dfficult due to static electricity, low fiber strength, etc. Otherwise, if it exceeds 50%, even the inner layer has rayon characteristics. Therefore, there are no problems of static electricity, low fiber strength, etc., but stability in water is reduced so that it is dfficult to obtain a uniform pile.
• alkali metal hydroxides such as sodum hydroxide, alkaline earth metal hydroxides such as calcium hydroxide, alkali metal carbonates such as sodum carbonate, etc. may be used.
• the aqieous alkali solution may comprise a reaction aide compatible with the alkali and capable of controlling the reaction rate.
• the reaction aide is comprised at 0.001 to 2.0 wt%.
• Commercially available examples of the reaction aide are Neorate NCB (Hankook Hne Chemicals), which is a phosphonium based compound, and KF Neorate NA-40 (Hankook Hne Chemicals) and Snogen PDS (Dae Young Chemical), which are quaternary ammonium compounds.
• the alkali-modfied pile yarn is napped, brushed, sanded, and resin-processed to align the textile along the drection of the warp or weft with an inclination.
• the saponified pile textile is brushed while being transferred along the wa ⁇ drection of the textile on a tenter eqipped with rotational brushes with dfferent shapes and types.
• the brushes are rotated along the wa ⁇ or weft drection dependng on the size and pu ⁇ ose of the rubbing cloth to be used.
• the pile is inclined with an angle of 5 to 40 degrees from a reference vertical line on the textile. If the pile is inclined with an angle of less than 5 degrees, scratches may occur on the alignment film. Otherwise, if it exceeds 40 degrees, alignment grooves are not formed adequately.
• a shrink-proofing agent such as a silicone-based elasticizer, etc. may be impregnated into the pile fabric to improve the mechanical stability of the pile yarn.
• kind and concentration of the added agents may be varied dependng on the pu ⁇ ose.
• the agents are not specially limited as long as they improve the mechanical stability of the pile yam.
• the inside textile of the pile fabric is coated or laminated using a coating agent, in order to prevent the pile yam from being released out of the textile and adhering to the alignment film during the aligning process.
• a coating agent at least one resin selected from the group consisting of polyurethane, polyvinyl acetate, polyacryl, polyamide, polyimide, polyester, and polyurea can be used. If the coating layer on the inside textile is too thick, the rubbing cloth is not tightly adhered to the rubbing roller, so that the rubbing becomes non-uniform. Otherwise, if the coating layer is too thin, the pile may be released from the textile and adhere to the alignment film during the aligning process, causing insufficient rubbing. Therefore, a preferable coating amount is 10 to 100 g/m 2 .
• the rubbing cloth of the present invention is capable of forming fine alignment grooves during the rubbing process of a liqid crystal dsplay device, and solving scratch and non-uniform rubbing problems with a simple modfication of an acetate pile yarn. Therefore, the present invention is capable of providng a liqid crystal dsplay device with significantly improved optical characteristics.
• a cupraammonium rayon filament 120 d 70f (Asahi, Japan) and a cupraammonium rayon filament 75 d 50f (Asahi, Japan) were used as wa ⁇ and weft, respectively, to weave a textile having a wa ⁇ density of 60/inch and a weft density of 117/inch.
• the obtained pile fabric was immersed in a Snotex SF-800 3% ows solution, a silicone based elasticizer of Dae Young Chemical.
• the fabric was napped 10 times each along the drection of the wa ⁇ and weft on a tenter eq ⁇ pped with brushes, so that the pile was inclined by 26° along the wa ⁇ drection.
• a polyvinyl acetate based coating agent was used to fix the aligned pile.
• the coating agent was impregnated in the inside ground textile and fixed by heat at 140 to 160 °C.
• the resultant pile fabric was cut, so that the overall thickness of the pile became 1.8 mm.
• Example 3 The same textile as in Example 1 was saponified with a reaction solution obtained by addng 1 g/L of Snogen PDS of Dae Young Chemical, a quaternary ammonium salt based reaction aide, to 20 wt% of a caustic soda solution to obtain a pile fabric having a weight reduction ratio of 19.8%. Then, it was immersed in a Snotex GR 6% ows solution, a glyoxal based shrink proofing agent of Dae Young Chemical, and brushing, coating, thermal fixing, and cutting were performed as in Example 1.
• a cupraammonium rayon filament 120 d 70f (Asahi, Japan) and a cupraammonium rayon filament 75 d 50f (Asahi, Japan) were used as wa ⁇ and weft, respectively, to weave a textile having a wa ⁇ density of 60/inch and a weft density of 129/inch.
• the resultant pile fabric was cut and pre-treated as in Example 1.
• Example 1 it was saponified with 5 wt% of a sodum carbonate solution per 100 wt% of the acetate fiber. Then, the pile fabric was immersed in a Snotex SF-800 3% ows solution, a silicone based elasticizer, of Dae Young Chemical. Brushing, coating, thermal fixing, and cutting were performed as in Example 1.
• Example 4 The same textile as in Example 3 was saponified with a reaction solution obtained by addng 1 g/L of Snogen PDS of Dae Young Chemical, a quaternary ammonium salt based reaction aide, to 20 wt% of a sodum carbonate solution to obtain a pile fabric having a weight reduction ratio of 19.5%. Then, it was immersed in a Snotex GR 6% ows solution, a glyoxal based shrink proofing agent of Dae Young Chemical, and brushing, coating, thermal fixing, and cutting were performed as in Example 1.
• a cupraammonium rayon filament 120 d 70f (Asahi, Japan) and a cupraammonium rayon filament 75 d 50f (Asahi, Japan) were used as wa ⁇ and weft, respectively, to weave a textile having a wa ⁇ density of 60/inch and a weft density of 98/inch.
• a viscous rayon filament 120 d 40f (Enka, Germany) was used as a pile yarn to weave a textile having a pile density eqial to that of Example 1.
• the resultant pile fabric was refined as in Example 1. Then, it was immersed in a Snotex GR 6% ows solution, a silicone based elasticizer of Dae Young Chemical. Brushing, coating, thermal fixing, and cutting were performed as in Example 1.
• a cupraammonium rayon filament 120d 70f (Asahi, Japan) and a cupraammonium rayon filament 75 d 50f (Asahi, Japan) were used as wa ⁇ and weft, respectively, to weave a textile having a wa ⁇ density of 60/inch and a weft density of 11 /inch.
• a viscous rayon filament 120d 40f (Enka, Germany) was used as pile yarn to weave a 2 textile having a pile density of 32,000/cm in a W shape using a conventional pile weaving machine.
• the resultant pile fabric was refined as in Example 1. Then, it was immersed in a Snotex GR 6% ows solution, a silicone based elasticizer of Dae Young Chemical. Brushing, coating, thermal fixing, and cutting were performed as in Example 1.
• Cutting strength of fiber A 50 mm-long sample was tested at a rate of 200 m min using a universal testing machine (ZWICK 1425, Germany). The sample was prepared from the fiber used to manufacture the pile.
• ® Frictional voltage of fiber Frictional voltage and half life were measured under the condtion of KS K 0555, 20 °C, 40% RH. Cotton was used as a counter-cloth.
• a rubbing cloth for a liqid crystal dsplay device may be simply manufactured by modfying a cellulose acetate pile fabric accordng to the present invention.
• the resultant rubbing cloth is capable of forming fine alignment grooves during the aligning process and solving the problems of scratch and non- uniform rubbing.

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• 2003
  • 2003-11-20 KR KR1020030082696A patent/KR100600792B1/ko active IP Right Grant
• 2004
  • 2004-11-04 CN CN2004800330928A patent/CN1879053B/zh active Active
  • 2004-11-04 WO PCT/KR2004/002836 patent/WO2005050303A1/en active Application Filing
  • 2004-11-04 JP JP2006541024A patent/JP4719157B2/ja active Active
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