Twisted (or Chiral) Nematic Or Supertwisted Nematic Patents (Class 349/179)
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Patent number: 6603521Abstract: A normally white reflection type liquid crystal display includes a polarization plate; a quarter wavelength plate; a transparent substrate; a transparent electrode; and a twisted nematic liquid crystal layer. The polarization plate, the quarter wavelength plate, the transparent substrate, the transparent electrode, and the twisted nematic liquid crystal layer are layered in sequence from a light inputting side, and the angle between the optical axis of the quarter wavelength plate and the transmission axis of the polarization plate is below 65 degrees and above 45 degrees, or below 45 degrees and above 25 degrees.Type: GrantFiled: June 20, 2002Date of Patent: August 5, 2003Assignee: NEC CorporationInventors: Teruaki Suzuki, Koichi Yanai
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Patent number: 6600537Abstract: A pi-cell liquid crystal device comprises a nematic liquid crystal layer (17) disposed between alignment layers (14,15) which provide a pretilt such that, at a zero applied field, the energy of the H-state is less than the energy of the V-state, which is less than the energy of the T-state. A drive arrangement (18) switches the pi-cell by applying a first electric field, at which the energy of the V-state is less than the energy of each of the H-state and the T-state, or a second smaller electric field, at which the energy of the H-state is less than the energy of each of the V-state and the T-state. The T-state may thus be avoided while maintaining high switching speeds.Type: GrantFiled: January 11, 2002Date of Patent: July 29, 2003Assignee: Sharp Kabushiki KaishaInventors: Michael John Towler, Elizabeth Jane Acosta, Harry Garth Walton
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Patent number: 6587179Abstract: A high contrast ratio reflective STN LCD structure including an glass substrate panel, a liquid crystal layer and a lower glass substrate panel. The upper glass substrate panel includes only one optical deflector. The phase compensating film disposed under the optical deflector has a quarter of wavelength. The liquid crystal molecules of the liquid crystal layer have torsion angle within 180° to 210°. The retardation value of the liquid crystal molecules is within 580 nm to 650 nm.Type: GrantFiled: June 28, 2001Date of Patent: July 1, 2003Assignee: Wintek CorporationInventors: Yi-Chun Wu, Shin-Tson Wu
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Patent number: 6583832Abstract: An ellipsoidal polarizing plate comprises two optically anisotropic layers, a polarizing membrane and a transparent protective film. Each of the optically anisotropic layers has a direction giving the maximum refractive index and a plane of the layer. The first optically anisotropic layer has an angle of 5° to 85° between the direction giving the maximum refractive index and the plane. The second optically anisotropic layer is optically positive and uniaxial. The second optically anisotropic layer has an angle of 0° to 5° between the direction giving the maximum refractive index and the layer plane.Type: GrantFiled: September 28, 2000Date of Patent: June 24, 2003Assignee: Fuji Photo Film., Ltd.Inventor: Yoji Ito
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Publication number: 20030104143Abstract: The invention relates to TN and STN liquid-crystal displays and to the novel nematic liquid-crystal mixtures used therein, characterized in that they comprise one or more compounds of the formula I 1Type: ApplicationFiled: June 27, 2002Publication date: June 5, 2003Applicant: Merck Patent GmbHInventor: Juliane Suermann
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Patent number: 6562421Abstract: A supertwisted nematic liquid crystal display comprising: a pair of substrates each having a liquid crystal orientation-controlling layer and a transparent electrode; a liquid crystal material held between said substrates; and at least one polarizing sheet provided on at least one of said substrates, wherein said liquid crystal material comprises: (a) a compound represented by formula (I): and (b) at least one compound selected from the group consisting of: compounds represented by formula (II): and compounds represented by formula (III):Type: GrantFiled: August 29, 2001Date of Patent: May 13, 2003Assignee: Dainippon Ink and Chemicals, Inc.Inventors: Go Sudo, Takeshi Kuriyama, Shotaro Kawakami, Hiroyuki Ohnishi, Haruyoshi Takatsu
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Patent number: 6549256Abstract: A liquid crystal device comprises a layer of nematic or long pitch cholesteric liquid crystal material contained between two cell walls. One wall (A) carries a surface treatment giving a first azimuthal alignment direction with or without a surface pretilt to liquid crystal molecules. The other wall (B) carries a surface treatment (17) capable of separately providing both a preferred, substantially homeotropic alignment of the adjacent liquid crystal, and a defined azimuthal second alignment direction to the adjacent liquid crystal dependent upon liquid crystal molecular arrangement. The first and second alignment directions are approximately orthogonal. Polarisers may be arranged on either side of the cell walls with their polarisation axes parallel or perpendicular to the two azimuthal directions. Alternatively an amount of dichroic dye may be incorporated in the liquid crystal material, and the device operated with one or two polarisers.Type: GrantFiled: August 4, 1998Date of Patent: April 15, 2003Assignee: Qinetiq LimitedInventors: Guy P Bryan-Brown, Carl V Brown, Ian C Sage
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Patent number: 6544602Abstract: The invention relates to supertwist liquid-crystal displays (SLCDs) having very short response times and good steepnesses and angle dependencies, and to the novel nematic liquid-crystal mixtures used therein, which are distinguished in that they comprise at least one compound of the formula IA and at least one compound of the formula IB in which Ra, Rb, Rc, Rd, Y1, Y2, n and p have the meaning given.Type: GrantFiled: May 4, 2000Date of Patent: April 8, 2003Assignee: Merck Patent Gesellschaft mit beschränkter HaftungInventors: Harald Hirschmann, Clarissa Weller, Georg Weber, Kazuo Totani, Akihiro Kojima
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Publication number: 20020186342Abstract: The invention provides a liquid crystal device capable of obtaining a bright image with a high display quality by controlling disclination caused by a lateral electric field developed across a space between pixels, or the like.Type: ApplicationFiled: March 28, 2002Publication date: December 12, 2002Applicant: SEIKO EPSON CORPORATIONInventor: Kinya Ozawa
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Patent number: 6466297Abstract: The invention relates to a method of preparing a broadband reflective polarizer comprising the blending a first mixture A comprising at least one achiral polymerizable mesogenic compound with a second mixture B comprising at least one chiral polymerizable mesogenic compound; and coating a layer of the blended mixture onto a first substrate and aligning the chiral mesogenic material in a planar orientation so that the axis of the molecular helix extends transversely to the layer.Type: GrantFiled: July 3, 2000Date of Patent: October 15, 2002Assignee: Merck Patent Geselleschaft mit Beschrankter HaftungInventors: Mark Goulding, David Coates, John Patrick, Mark Verrall, John Argent
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Patent number: 6440506Abstract: The invention relates to supertwist liquid-crystal displays (STN-LCDs) having short switching times and good steepnesses and angle dependencies, and to the novel nematic liquid-crystal mixtures used therein, which comprise compounds having a 3,4,5-trifluorophenyl group together with compounds of formula I wherein R3 is an alkenyl group with 2 to 7 C atoms, R4 is an optionally fluorinated alkyl, alkoxy, alkenyl or alkenyloxy group with 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups can be replaced by —O—, —CH═CH—, —CO—, —OCO— or —COO— in such a manner that O atoms are not directly adjacent to one another, or, in case m=1, R4 can also be Q—Y, Q is CF2, OCF2, CFH, OCFH or a single bond, Y is F or Cl, L1 and L2 are each independently H or F, and m is 0 or 1.Type: GrantFiled: November 19, 1999Date of Patent: August 27, 2002Assignee: Merck Patent Gesellschaft mit beschrankter HaftungInventors: Akihiro Kojima, Fumio Shimano, Yukiko Fujii, Izumi Saito, Kazuo Totani
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Publication number: 20020093620Abstract: The present invention provides a liquid crystal display device comprising a liquid crystal layer sandwiched between an upper substrate and a lower substrate having a twist angle in the range of about 40 to 65 degrees and a light diffusive reflective electrode having recesses and projections provided on the lower substrate wherein a product of the height of the recesses and projections and a birefringence of the liquid crystal layer is in the range of about 10 to 53 nm at the twist angle of about 40 degrees and about 10 to 64 nm at the twist angle of about 65 degrees, respectively.Type: ApplicationFiled: August 16, 2001Publication date: July 18, 2002Inventors: Osamu Itou, Shinichi Komura
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Publication number: 20020044252Abstract: The invention pertains to a single-polarizer, normally black reflective display comprising an STN-LCD cell, a reflector, one polarizer, and a twisted retardation layer, characterized in that the sign of the twist angle of the STN-LCD cell (TSTN) is opposite to the twist angle of the twisted retardation layer (TRL) and that |TSTN-TRL| is 30° to 90°, and |RSTN-RRL| is 10-700 nm, wherein RSTN and RRL stand for the retardation values of the STN-LCD cell and the retardation layer, respectively, and that the difference between the dispersion of the retardation layer and the STN-LCD cell is more than 5%, wherein the dispersion is defined as the ratio of the retardation value at &lgr;=436 nm to the retardation value at &lgr;=668 nm.Type: ApplicationFiled: May 15, 2001Publication date: April 18, 2002Inventor: Martin Bosma
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Publication number: 20020033929Abstract: A supertwisted nematic liquid crystal display having twist angle of 180 to 270° C.Type: ApplicationFiled: July 25, 2001Publication date: March 21, 2002Applicant: Dainippon Ink and Chemicals, Inc.Inventors: Go Sudo, Shotaro Kawakami, Haruyoshi Takatsu, Hiroyuki Ohnishi, Naoe Katoh
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Patent number: 6353467Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0° and 90°, and preferably between 50° and 80° is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than −25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15°.Type: GrantFiled: October 14, 1999Date of Patent: March 5, 2002Assignee: Chorum Technologies Inc.Inventors: Charles Wong, Yen-Chen Chen, Kuang-Yi Wu, Jian-Yu Liu
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Patent number: 6295113Abstract: A twisted nematic color liquid crystal display. The liquid crystal display comprises parallel glass substrates covered by a transparent electrode and an alignment film, a twisted nematic liquid crystal between the glass substrates, a retardation layer and polarizers. Between the glass substrates, a liquid crystal unit which forms the liquid crystal has a twist angle about 70 to about 180 about degree while free of an externally applying voltage. A product of anisotropy of refractive index for the twisted nematic liquid crystal &Dgr;n and the thickness d thereof, that is, &Dgr;n·d, is set in a range between about 1100 Å to about 2000 Å. Without using a passive device such as an external color light source or color filter, a multi-color or full color display is formed by an active controlling method of birefringence of electric field via applying a voltage on the transparent electrode.Type: GrantFiled: May 17, 1999Date of Patent: September 25, 2001Assignee: Picvue Electronics, Ltd.Inventor: Chiu-Lien Yang
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Liquid crystal display panel implementing bistable liquid crystal and method of fabricating the same
Publication number: 20010017685Abstract: A liquid crystal display panel implementing a bistable liquid crystal and fabricating the same is disclosed in the present invention. Specifically, a method of fabricating a liquid crystal display panel having first and second substrates, the method includes forming a first electrode on the first substrate, forming a second electrode on the second substrate, assembling the first and second substrates, forming a bistable twist nematic liquid crystal layer between the first and second substrates, wherein the bistable twist nematic liquid crystal layer having a monomer, aligning the bistable twist nematic liquid crystal layer by applying electric fields, and forming polymer networks by exposing the bistable twist nematic liquid crystal layer to light.Type: ApplicationFiled: January 30, 2001Publication date: August 30, 2001Inventor: Ku-Hyun Park -
Patent number: 6201593Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0° and 90°, and preferably between 50° and 80° is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than −25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15°.Type: GrantFiled: October 14, 1999Date of Patent: March 13, 2001Assignee: Chorum Technologies, Inc.Inventors: Charles Wong, Yen-Chen Chen, Kuang-Yi Wu, Jian-Yu Liu
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Patent number: 6188455Abstract: An ECB mode liquid crystal display device in which birefringence of liquid crystal is controlled by an applied voltage. The liquid crystal display device has: a drive liquid crystal cell having a pair of substrates disposed to face each other through a predetermined gap, each substrate having an electrode on one surface thereof, and a liquid crystal layer disposed between the pair of substrates. The birefringence of the liquid crystal layer of the drive liquid crystal cell is controlled by a voltage applied between electrodes, and an optical compensation unit is disposed between the drive liquid crystal cell and one of the pair of polarizers. The optical compensation unit includes a lamination of a left-twist liquid crystal layer of liquid crystal molecules having a chirality in a left-twist direction and a right-twist liquid crystal layer of liquid crystal molecules having a chirality in a right-twist direction.Type: GrantFiled: May 28, 1998Date of Patent: February 13, 2001Assignee: Stanley Electric Co., Ltd.Inventor: Tsuyoshi Yamamoto
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Patent number: 6141074Abstract: A liquid crystalline light modulating pixel includes first and second cell wall structures and nematic liquid crystal disposed therebetween. The first and second cell wall structures cooperate with the liquid crystal to form four liquid crystal domains within the pixel. The liquid crystal in each of the domains exhibits a twisted nematic liquid crystal structure and the orientation of the liquid crystal director of the liquid crystal adjacent one of the cell wall structures in at least two domains is different.Type: GrantFiled: December 18, 1997Date of Patent: October 31, 2000Assignee: Kent State UniversityInventors: Philip J. Bos, Hemasiri K. Vithana, David L. Johnson, Jianmin Chen
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Patent number: 6122026Abstract: A sufficiently wide viewing angle characteristic is obtained while a sufficient front contrast is ensured. With respect to the light transmitted by a polarizing plate and a phase difference plate before exiting from a liquid crystal display device, the viewing angle in the 12-6 o'clock direction is improved by a phase difference plate. By a light diffusing plate, a sufficient front contrast is ensured by causing the light to exit in the direction of the normal and the light is diffused in the 9-3 o'clock direction where the viewing angle is not improved by the phase difference plate. In the case where the light diffusing plate has a double refractivity, the liquid crystal display apparatus is arranged so that the light is transmitted by the light diffusing plate after transmitted by a polarizing plate.Type: GrantFiled: June 17, 1997Date of Patent: September 19, 2000Assignee: Sharp Kabushiki KaishaInventors: Tomoo Takatani, Takeyuki Ashida
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Patent number: 6108069Abstract: The present invention provides a liquid crystal display panel that can improve alignment stability, display uniformity, and display quality. By facilitating stable alignment of liquid crystal materials and inducing a twisted alignment, a uniform display can be provided and the balance among the optical characteristics can be improved. In particular, a stable alignment margin can be obtained when the cell thickness d is 7 .mu.m or more and when the twist angle for liquid crystal molecules is 240.degree. or less.Type: GrantFiled: June 11, 1998Date of Patent: August 22, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroyuki Okada, Kazuhiro Joten
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Patent number: 6094246Abstract: A twisted nematic liquid crystal-based electro-optic modulator with a twist angle between 0.degree. and 90.degree., and preferably between 50.degree. and 80.degree. is provided. The modulator provides a relatively rapid switching time such as less than about 50 milliseconds, and provides relatively large extinction ratios, such as greater than -25 dB. Preferably the liquid crystal entrance director differs from the polarization direction by a beta angle of about 15.degree..Type: GrantFiled: January 6, 1998Date of Patent: July 25, 2000Assignee: Chorum TechnologiesInventors: Charles Wong, Yen-Chen Chen, Kuang-Yi Wu, Jian-Yu Liu
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Patent number: 6072558Abstract: A display characteristic of a high contrast ratio and a high transmittance through the application of a chiral nematic liquid crystal medium switchable between metastable states via Frederick's transition is utilized as a liquid crystal electrooptical element. The electrooptical element employs a white light source and is switchable between metastable states in which the polarization axes of both polarization plates are set to predetermined angles P and A according to the initial state of the liquid crystal medium and the product, R, of the thickness, d, and the difference, .DELTA.n, in the refractive indices of the liquid crystal medium for extraordinary light, n.sub.e, and ordinary light, n.sub.o (.DELTA.n=n.sub.e -n.sub.o).Type: GrantFiled: June 9, 1997Date of Patent: June 6, 2000Assignee: Seiko Epson CorporationInventors: Takaaki Tanaka, Yuzuru Sato
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Patent number: 6063456Abstract: Supertwist liquid-crystal displays (SLCDs) with outstanding properties are obtained if the nematic liquid-crystal mixtures used therein comprise at least one compound selected from the formulae 1A and 1B ##STR1## and at least one compound of the formula 1C ##STR2## in which R.sup.a is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms,R.sup.b is alkyl or alkoxy having 1 to 5 carbon atoms,Z is --COO--, --CH.sub.2 CH.sub.2 -- or a single bond, andL.sup.a, L.sup.b, L.sup.c, L.sup.d, L.sup.e, L.sup.f, L.sup.g, and L.sup.h in each case independently of one another are H or F,with the proviso that the 1,4-phenylene rings carry not more than 2 fluorine atoms per ring,R.sup.3 is an alkenyl group having 2 to 7 carbon atoms,R.sup.4 is R.sup.a or R.sup.3 andc is 0 or 1.Type: GrantFiled: August 3, 1998Date of Patent: May 16, 2000Assignee: Merck Patent Gesellschaft mit Beschrankter HaftungInventors: Harald Hirschmann, Sven Schupfer, Volker Reiffenrath, Sabine Schoen
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Patent number: 6056894Abstract: TN liquid-crystal displays and supertwist liquid-crystal displays (SLCDs) having very short response times and good steepnesses and angle dependencies are obtained by using nematic liquid-crystal mixtures which comprise at least one compound of formula IA ##STR1## and at least one compound of the formula IB ##STR2## in which R.sup.a, R.sup.b, R.sup.c, L and r are as defined herein.Type: GrantFiled: February 26, 1998Date of Patent: May 2, 2000Assignee: Merck Patent GmbHInventors: Harald Hirschmann, Clarissa Weller, Volker Reiffenrath
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Patent number: 6054193Abstract: Supertwist liquid-crystal displays having excellent properties are obtained if the nematic liquid-crystal mixture comprises at least one compound of the formula I: ##STR1## and at least one compound of the formula I.sup.* : ##STR2## in which R.sup.1 is alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 12 carbon atoms,R.sup.2 is alkyl or alkoxy having 1 to 8 carbon atoms,Z is --COO--, --CH.sub.2 CH.sub.2 or a single bond,one of the radicals L.sup.1 and L.sup.2 is F and the other is H,Alkenyl.sup.* is an alkenyl radical having up to 7 carbon atoms,L.sup.* is H or F, andR.sup.* is F or an alkyl group having 1 to 12 carbon atoms which is unsubstituted or non-substituted.Type: GrantFiled: July 6, 1998Date of Patent: April 25, 2000Assignee: Merck Patent Gesellschaft mit Beschrankter HaftungInventors: Harald Hirschmann, Marcus Reuter, Volker Reiffenrath
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Patent number: 6055028Abstract: An electric field that is parallel with a TFT substrate is formed by a pair of electrodes formed on the TFT substrate. Liquid crystal molecules in a light modulating layer are caused to respond electro-optically to the electric field. The light modulating layer is constituted of a liquid crystal material, an optically active substance, and a dichroic dye. The spiral pitch p [.mu.m] of the light modulating layer, the cell thickness d [.mu.m], the twist angle n of liquid crystal molecules, and the interelectrode interval L [.mu.m] are set in ranges of 1.ltoreq.p.ltoreq.15, 1.ltoreq.d.ltoreq.10, n.ltoreq.300.degree., and L<25.Type: GrantFiled: February 12, 1997Date of Patent: April 25, 2000Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Takeshi Nishi, Rumo Satake, Yoshiharu Hirakata
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Patent number: 6025895Abstract: On the substrate (108) are made reflecting type picture element electrodes (107), of Cr, and on substrate 101 are made transference picture element electrodes (102), of ITO. On both substrates (108, 101) parallel alignment films (106, 103), consisting of polyimide alignment films, are each made, but rubbing treatment is not administered. Between the substrates (108. 101) polymer dispersion liquid crystal, in which liquid crystal (105) and polymer (104) are in a state of mutual orientation dispersion, is placed. Liquid crystal (105) is parallel oriented randomly near the substrate surfaces, and twisted approximately 90.degree. between the substrates (101, 108). Also, the orientation domains from the liquid crystal random orientation are evenly multidomained at the level of approximately 1-3 .mu.m. Because they are randomly oriented in this way, directivity of scatter is improved, and operation voltage is decreased.Type: GrantFiled: August 1, 1996Date of Patent: February 15, 2000Assignee: Seiko Epson CorporationInventors: Masayuki Yazaki, Hidekazu Kobayashi, Shuhei Yamada, Hidehito Iisaka, Yutaka Tsuchiya, Eiji Chino
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Patent number: 6011606Abstract: An active matrix type liquid crystal display apparatus having a pair of substrates sandwiching a liquid crystal layer. A group of electrodes form a matrix of pixels and an active device, each of the group of electrodes being provided between the liquid crystal and one of the substrates. The electrodes are arranged so as to apply an electric field, mainly parallel to the substrates. The resistivity of the liquid crystal layer is lower than or equal to 1.times.10.sup.14 .OMEGA..multidot.cm. The relationship between the elasticity constant K2 and the dielectric anisotropy .DELTA..epsilon. satisfies the equation K.sub.2 /.DELTA..epsilon.<9.0.times.10.sup.-8 [dyn]. Further, a relationship between a gap between a pixel electrode and a common electrode and a gap between the pair of substrates is satisfied.Type: GrantFiled: March 17, 1995Date of Patent: January 4, 2000Assignee: Hitachi, Ltd.Inventors: Masahito Ohe, Katsumi Kondo, Masuyuki Ota
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Patent number: 5949513Abstract: Methods of manufacturing a liquid crystal display ("LCD"); specifically, a multi-color LCD, e.g., a red-green-blue ("RGB") LCD. The methods include the steps of: (1) depositing a twist agent on a first substrate, the twist agent becoming an in situ twist agent, (2) bringing a second substrate into proximity with the first substrate to form at least one interstitial region between the second and first substrates, (3) introducing liquid crystal ("LC") having an initial pitch into the at least one interstitial region proximate the in situ twist agent and (4) stimulating the LC and the in situ twist agent to cause the LC and the in situ twist agent to mix in situ, the in situ twist agent changing the initial pitch of the LC.Type: GrantFiled: October 13, 1998Date of Patent: September 7, 1999Assignee: Advanced Display System, Inc.Inventors: Yao-Dong Ma, Bao-Gang Wu
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Patent number: 5940158Abstract: This invention provides a pointing device which gives a feeling of operation closer to the feel of people without requiring an operation space. While a writing instrument having a pen grip (2) fitted thereto is held by a hand, a gripping force is applied by fingers as if a line were drawn in a moving direction of a cursor (the line need not be drawn in practice). The pressures of the fingers are measured by strain gauges (28a, 28b, and 28c), which send their corresponding voltage values to a CPU (40). The CPU (40) calculates the moving direction and distance of the cursor on the basis of the voltage values. Then, receiving the data, the cursor is moved to a designated position. When a microswitch (110) is pushed, the cursor position is made definite.Type: GrantFiled: December 16, 1996Date of Patent: August 17, 1999Assignee: Japan Nesamac CorporationInventor: Kazuki Kawabata
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Patent number: 5936692Abstract: The invention relates to a multi-domain liquid-crystal display device comprising two substantially parallel substrates which are provided with an electrode layer and an orientation layer. A layer of a nematically ordered liquid-crystalline material comprising a chiral dopant is sandwiched between the substrates. The layer is structured in such a manner that the pixels of the layer are composed of at least two types of sub-pixels in which the twist senses of the liquid-crystalline material are mutually opposite. This construction in accordance with the invention is achieved by differentiating the composition of the chiral dopant in the different types of sub-pixels. This is attained by employing isomerizable chiral dopants and/or diffusion techniques in combination with local exposure of the liquid-crystal layer. The invention also provides methods of manufacturing such multi-domain liquid-crystal display devices.Type: GrantFiled: June 2, 1998Date of Patent: August 10, 1999Assignee: U.S. Philips CorporationInventor: Peter Van De Witte
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Patent number: 5900852Abstract: A high speed multiplex-driven liquid crystal display device is capable of utilizing a bistable nematic liquid crystal medium while maintaining high contrast, fast switching capability and a wide viewing angle. The chiral nematic liquid crystal medium has a twisted structure wherein a first voltage waveform applied in a first time period brings on Frederick's transition followed by a selected second voltage waveform applied in a second time period capable of generating one of two selectable metastable states representing switchable bistable states.Type: GrantFiled: June 14, 1996Date of Patent: May 4, 1999Assignee: Seiko Epson CorporationInventors: Takaaki Tanaka, Yuzuru Sato, Hiroaki Nomura
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Patent number: 5886754Abstract: A projection-type display device using twisted nematic liquid crystal light valves having multi-twist and/or multi-polarization angles. The photoelectric transfer characteristics of three light valves are optimized for reflecting red, green and blue light with high efficiency and similar reflectivity by selecting proper twisted angle and polarization angle for each corresponding liquid crystal light valve. The twisted angle or polarization biasing angle of each light valve may be different.Type: GrantFiled: January 17, 1997Date of Patent: March 23, 1999Assignee: Industrial Technology Research InstituteInventor: Chen-Lung Kuo
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Patent number: 5880798Abstract: A twisted nematic liquid crystal device has a liquid crystal layer between a pair of alignment layers. Glass plates with electrodes are disposed on opposite sides of the layers. The alignment layers have their alignment directions disposed mutually perpendicular and at .+-.45.degree. with respect to adjacent linear polarizers. The pretilt angle of liquid crystal molecules in a surface region of the layer adjacent the alignment layer is different to that of liquid crystal molecules in a surface region of the layer adjacent the alignment layer.Type: GrantFiled: June 24, 1997Date of Patent: March 9, 1999Assignee: Sharp Kabushiki KaishaInventors: Harry Garth Walton, Martin David Tillin, Michael John Towler
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Patent number: 5876626Abstract: Supertwist liquid crystal displays having very short switching times are obtained if the nematic liquid crystal mixture contains at least one component chosen from group A consisting of compounds of the formulae AI to AVI: ##STR1## wherein R.sup.1 and R.sup.2 in each case independently of one another are each R and R is alkyl having 1-12 C atoms, wherein one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, --CH.dbd.CH--, --CO--, --O--CO-- or --CO--O--, and up to four other components.Type: GrantFiled: December 7, 1994Date of Patent: March 2, 1999Assignee: Merck patent Gesellschaft mit Beschrankter HaftungInventors: Georg Weber, Herbert Plach, Takamasa Oyama, Hiroki Yoshitake, Bernhard Scheuble, Reinhard Hittich, Hans Adolf Kurmeier, Eike Poetsch, Klaus Peter Stahl
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Patent number: 5856859Abstract: A reflective liquid crystal display device includes a pair of substrates and a liquid crystal layer interposed therebetween. The liquid crystal layer includes a liquid crystal material and a dichroic dye contained therein, and long axis of liquid crystal molecules near the substrate is substantially parallel to the substrate. A plurality of parameters of the reflective liquid crystal display device are set so that a product K.sub.M cd of a value K.sub.M, a dye concentration c and a thickness d of the liquid crystal layer satisfies the following relationship:3.0S.sup.2 -7.3S+5.7.ltoreq.K.sub.M cd.ltoreq.14.7S.sup.2 -15.1S+6.15wherein, the value K.sub.M is a value defined by absorption coefficients for linearly-polarized light substantially parallel to and perpendicular to the liquid crystal molecules, and an order parameter S of the liquid crystal layer.Type: GrantFiled: July 2, 1997Date of Patent: January 5, 1999Assignee: Sharp Kabushiki KaishaInventors: Yasuhisa Itoh, Naofumi Kimura
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Patent number: 5841498Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including orientation angle .beta..sub.o, and others, of the liquid crystal molecules in the layer.Type: GrantFiled: April 4, 1996Date of Patent: November 24, 1998Assignee: Merck Patent Gesellschaft Mit Beschrankter HaftungInventors: Gunter Baur, Waltraud Fehrenbach, Barbara Weber Ne Staudacher, Friedrich Windscheid, Rudolf Kiefer
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Patent number: 5841499Abstract: An electro-optical display device comprising a liquid crystal layer achieves switching using an electric field component which is predominantly parallel to the surface of the liquid crystal layer. Low dependence of image contrast on viewing angle is achieved by selection of parameters including pretilt angle .alpha..sub.0, orientation angle .beta..sub.0, etc. of the liquid crystal molecules in the layer. Reflection mode devices are described.Type: GrantFiled: April 4, 1996Date of Patent: November 24, 1998Assignee: Merck Patent Gesellschaft Mit Beschrankter HaftungInventors: Gunter Baur, Waltraud Fehrenbach, Barbara W. Ne Staudacher, Friedrich Windscheid, Rudolf Kiefer
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Patent number: 5838408Abstract: This invention refers to a liquid crystal device that provides a color display by utilizing a colorization phenomenon caused by double refraction birefringence of a liquid crystal, wherein the color tone that appears when no voltage or a non-selected voltage is applied is white or a non-color close thereto, and at least two colors are displayed when a voltage is applied, and electronic equipment in which this liquid crystal device is installed.A liquid crystal device which is capable of displaying colors without using color filters and which is also capable of displaying white or a non-color close thereto is implemented by optimizing the value of .DELTA.n.multidot.d of the liquid crystal and the relationship between the value of .DELTA.n.multidot.d of the liquid crystal and the value of retardation (R) of an optically anisotropic substance such as a retardation film.In other words, the liquid crystal cell and the optically anisotropic substance should be such as to satisfy the following relationships:.DELTA.Type: GrantFiled: July 8, 1996Date of Patent: November 17, 1998Assignee: Seiko Epson CorporationInventors: Yasuyuki Inoue, Chiyoaki Iijima, Toshihiko Tsuchihashi
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Patent number: 5825451Abstract: Methods of manufacturing a liquid crystal display ("LCD"); specifically, a multi-color LCD, e.g., a red-green-blue ("RGB") LCD. The methods include the steps of: (1) depositing a twist agent on a first substrate, the twist agent becoming an in situ twist agent, (2) bringing a second substrate into proximity with the first substrate to form at least one interstitial region between the second and first substrates, (3) introducing liquid crystal ("LC") having an initial pitch into the at least one interstitial region proximate the in situ twist agent and (4) stimulating the LC and the in situ twist agent to cause the LC and the in situ twist agent to mix in situ, the in situ twist agent changing the initial pitch of the LC.Type: GrantFiled: October 17, 1997Date of Patent: October 20, 1998Assignee: Advanced Display Systems, Inc.Inventors: Yao-Dong Ma, Bao-Gang Wu
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Patent number: 5812229Abstract: A liquid crystal display device (10) includes a front polarizer (12), a liquid crystal cell (14), a retardation film (16), a back polarizer (18), and a reflective holographic optical element (20). Diffuse ambient light illuminates the front polarizer (12), which polarizes the ambient light and transmits the polarized light to the liquid crystal cell (14). The liquid crystal cell (14) receives the polarized light and transmits polarized light derived from the incident polarized light to the retardation film (16). The retardation film (16) receives the polarized light and transmits polarized light, including light within a selected spectral band. The back polarizer (18) receives the polarized light from the retardation film (16) and selectively transmits polarized light derived from the incident polarized light.Type: GrantFiled: May 1, 1996Date of Patent: September 22, 1998Assignee: Motorola, Inc.Inventors: Alan G. Chen, Kevin W. Jelley, George T. Valliath
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Patent number: 5793451Abstract: In a display device having a TN liquid crystal cell which can be illuminated by transmitted light from a source of light, the nematic liquid crystal substance of which cell contains a coloring substance. The control regions of the TN liquid crystal cell can be acted on by an actuation voltage between an actuation level and a non-actuation level of the electro-optic characteristic curve, in which connection bright signs can be shown on a dark display surface by the liquid crystal cell. The liquid crystal cell can be acted on by an actuation voltage between the actuation level and a non-actuation level in the undershoot region of the characteristic having the least transmission.Type: GrantFiled: January 30, 1997Date of Patent: August 11, 1998Assignee: VDO Adolf Schindling AGInventors: Peter Brandt, Dietmar Tippl
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Patent number: 5781263Abstract: A liquid crystal display device permitting low voltage driving which presents good display quality for a long time and excellent characteristics in low power consumption when voltage is supplied at a high temperature of about 50.degree. C. under a driving condition of a low frequency of 200 or less in terms of the number of polarity inversion per second. The display device includes a liquid crystal composition in which the voltage corresponding to 50% threshold value is 1.5 V or less is selected, and a fluorine-containing polymer material such as a fluorine-containing polyimide is used.Type: GrantFiled: March 13, 1997Date of Patent: July 14, 1998Assignee: Optrex CorporationInventors: Jun Kawagoe, Satoru Ihara, Hitoshi Ooaku
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Patent number: 5748277Abstract: A flat-panel liquid crystal display. The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements at a refresh rate 1000 scan lines per second. The driver circuitry activates the liquid crystal domains into homeotropic states over a relatively long activation period and then, during a short (.about.1 msec.) selection period, either keeps the domains in a homeotropic state or initiate a transition to the transient twisted planar state. The drivers then activate the domains in an evolution phase to provide either focal conic or twisted planar end states across the two-dimensional array of picture elements.Type: GrantFiled: February 17, 1995Date of Patent: May 5, 1998Assignee: Kent State UniversityInventors: Xiao-Yang Huang, Philip J. Bos, Deng-Ke Yang
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Patent number: 5748162Abstract: A liquid crystal device capable of being driven on a time division basis includes a liquid crystal panel sandwiching a liquid crystal layer having a twisted helical structure and preferably being disposed inside a pair of opposing polarizers, and a driving circuit for driving the liquid crystal panel. The liquid crystal layer if formed of a nematic liquid crystal material having a helical structure twisted by at least 180 degrees and the panel is driven on a time division driving basis in which the bias ratio is no less than 1/4 and no greater than 1/2. The driving voltage needed for operation of the liquid crystal device can thereby be substantially decreased.Type: GrantFiled: March 22, 1995Date of Patent: May 5, 1998Assignee: Seiko Instruments Inc.Inventor: Takayoshi Hanami
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Patent number: 5729318Abstract: The present invention provides a liquid crystal display device including a pair of electrode substrates and a display medium sandwiched between the electrode substrates and including a polymeric wall and liquid crystal regions at least partly surrounded by the polymeric wall. In this liquid crystal display device, the polymeric wall is tightly attached to both the electrode substrates. Furthermore, the invention also provides a method for producing a liquid crystal display device including a pair of electrode substrates, at least one of which is transparent, and a display medium including a polymeric wall and liquid crystal regions at least partly surrounded by the polymeric wall and sandwiched between the electrode substrates.Type: GrantFiled: May 25, 1995Date of Patent: March 17, 1998Assignee: Sharp Kabushiki KaishaInventors: Nobuaki Yamada, Masahiko Kondo, Masayuki Okamoto, Shuichi Kozaki
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Patent number: 5606442Abstract: A photocurable polymer precursor added to a liquid crystal material polymerizes to form a mixture that significantly lowers the threshold and saturation voltages of a standard twisted nematic cell. The performance characteristics of the resulting display device resembles those of a device with a very high pretilt, thereby providing an economical method of fabricating liquid crystal cells of a type that require a high pretilt alignment. The presence of the polymer substantially reduces adverse ion-related effects such as optical droop and charge retention in the liquid crystal display device.Type: GrantFiled: March 21, 1995Date of Patent: February 25, 1997Assignee: Tektronix, Inc.Inventors: Philip J. Bos, Jolly A. Rahman