Within Nematic Phase Patents (Class 349/177)
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Publication number: 20030011740Abstract: A liquid crystal device has inorganic alignment layers (36, 42) disposed on a surface of a liquid crystal layer side of a pair of the substrates, when the range of the average pre-tilt angle &thgr; of liquid crystal molecules 50a of the liquid crystal layer is 5 degrees≦&thgr;≦20 degrees, twist angle &phgr; of the liquid crystal molecules (50a) of the liquid crystal layer, cell gap d, and helical pitch P of the liquid crystal molecules of the liquid crystal layer satisfy the relationship of (0.6/360)&phgr;<d/P<(1.4/360)&phgr;, and when the range of the average pre-tilt angle &thgr; of liquid crystal molecules 50a of the liquid crystal layer is &thgr;>20 degrees, twist angle &phgr; of the liquid crystal molecules (50a) of the liquid crystal layer, cell gap d, and helical pitch P of the liquid crystal molecules of the liquid crystal layer satisfy the relationship of (0.8/360)&phgr;<d/P<(1.6/360)&phgr;.Type: ApplicationFiled: February 19, 2002Publication date: January 16, 2003Applicant: SEIKO EPSON CORPORATIONInventors: Takaaki Tanaka, Yasushi Yamazaki
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Publication number: 20020196404Abstract: A chiral nematic liquid crystal composition which contains a nematic liquid crystal mixture and a chiral agent, which exhibits a cholesteric phase at room temperature and which selectively reflects light of a specified wavelength, wherein the chiral agent has an anisotropy of dielectric constant within a range from 12 to 60. Such a chiral nematic liquid crystal composition may have a larger anisotropy of dielectric constant than the nematic liquid crystal mixture before being mixed with the chiral agent. Alternatively, in such a chiral nematic liquid crystal composition, the anisotropy of dielectric constant of the chiral agent may be larger than that of the nematic liquid crystal mixture. By filling such a chiral nematic liquid crystal composition between transparent substrates, a liquid crystal cell is fabricated, and by stacking such liquid crystal cells in three layers, a reflective type full-color liquid crystal display can be produced.Type: ApplicationFiled: May 23, 2002Publication date: December 26, 2002Applicant: MINOLTA CO., LTD.Inventors: Hideaki Ueda, Takeshi Kitahora, Fumie Motoori
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Publication number: 20020196403Abstract: A bistable nematic liquid crystal device includes an array of holes (8) in an alignment layer (6) on at least one cell wall (2). The alignment layer (6) induces a substantially planar local alignment of liquid crystal molecules. The holes (8) have a shape and/or orientation to induce the liquid crystal director adjacent the holes (8) to adopt two different tilt angles in substantially the same azimuthal direction. The arrangement is such that two stable liquid crystal molecular configurations can exist after suitable electrical signals have been applied to the electrodes.Type: ApplicationFiled: May 21, 2002Publication date: December 26, 2002Inventors: Stephen Christopher Kitson, Adrian Derek Geisow, John Christopher Rudin
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Patent number: 6469768Abstract: A liquid crystal display includes front and rear insulating substrates, each having inner and outer surfaces. The inner surface of the rear substrate faces the inner surface of the front substrate. A transparent electrode is formed on the inner surface of the front substrate, and a mirror electrode made with a reflective material is formed on the inner surface of the rear substrate. A polarizer is attached on the outer surface of the front substrate, and homogeneously aligning films are coated on the transparent and the mirror electrodes, followed by rubbing unidirectionally. A liquid crystal layer is interposed between the homogeneously aligning films on the two substrates. The liquid crystal layer is composed of a nematic liquid crystal material which has positive dielectric anisotropy and a chiral dopant to have a twisted structure. The molecular director in the liquid crystal layer is initially in the &pgr;-twisted state.Type: GrantFiled: April 15, 1999Date of Patent: October 22, 2002Assignee: Samsung Display Devices Co., Ltd.Inventor: Sin-Doo Lee
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Publication number: 20020130995Abstract: An optical diffusing plate that gives a anisotropic scattering of a linearly polarized light and has an excellent diffusion property in a scattering direction, and that is suitable for improving visibility, brightness of a liquid crystal display,Type: ApplicationFiled: January 7, 2002Publication date: September 19, 2002Inventors: Sadahiro Nakanishi, Minoru Miyatake, Shusaku Nakano, Amane Mochizuki
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Publication number: 20020067458Abstract: A polarized light reflecting element includes a plurality of stacked cholesteric liquid crystal layers. Each cholesteric liquid crystal layer is polymerized and has a helical liquid crystal molecule array and a helical axis that extends substantially in the normal direction. The in-plane mean value &agr; of the respective helix angles of liquid crystal molecules is nearly n&pgr; (n=1, 2, 3, . . . ). The cholesteric liquid crystal layers have their liquid crystal molecules continuously oriented on the interfaces between them, and form one smooth helical structure as a whole.Type: ApplicationFiled: November 14, 2001Publication date: June 6, 2002Inventors: Toshiya Ohtake, Yuzo Hisatake
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Patent number: 6384892Abstract: In a liquid crystal display device, the dielectric constants (∈) and resistivities (&rgr;) of the liquid crystal material and the layers of orienting material have such values that the liquid crystal display device can be driven by means of a DC voltage.Type: GrantFiled: January 13, 2000Date of Patent: May 7, 2002Assignee: U.S. Philips CorporationInventors: Mark T. Johnson, Adrianus A. Van Der Put
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Publication number: 20020047982Abstract: Creation of display image burn-in phenomena otherwise occurring due to the presence of an internal residual voltage(s) is suppressed. The polarization relaxation time constant &tgr; of a dielectric film layer existing between a liquid crystal drive electrode and a liquid crystal layer is specifically set to fall within a range of five minutes.Type: ApplicationFiled: September 12, 2001Publication date: April 25, 2002Applicant: Hitachi, Ltd.Inventors: Hidehiro Sonoda, Noboru Kunimatsu, Setsuo Kobayashi, Katsuhiko Ishii
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Patent number: 6348961Abstract: A reflective type liquid crystal display which has a liquid crystal composition exhibiting a cholesteric phase in a room temperature and a columnar structure between substrates with ITO electrodes thereon. The liquid crystal composition is a chiral nematic liquid crystal composition which is produced by adding a chiral agent at a ratio within a range from 10 wt % to 45 wt % to nematic liquid crystal which contains a nematic liquid crystal component with a polar group at not less than 25 wt % and of which transition temperature to isotropic phase is within a range from 70° C. to 150° C. The anisotropy of refractive index of the liquid crystal composition is 0.10 to 0.22, and the anisotropy of dielectric constant is 5 to 30.Type: GrantFiled: August 9, 1999Date of Patent: February 19, 2002Assignee: Minolta Co., Ltd.Inventors: Masako Iwamatsu, Nobuyuki Kobayashi, Hideaki Ueda
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Publication number: 20020015131Abstract: A liquid crystal device showing performances, such as good viewing angle characteristic, high contrast, high-speed responsiveness, high resolution and high productivity is given by forming a layer of discotic liquid crystal placed in an edge-on and uniaxial alignment state. In the liquid crystal layer, the discotic liquid crystal may preferably assume a nematic discotic layer and co-present with a rod-shaped liquid crystal in mutually separated phases.Type: ApplicationFiled: April 6, 2001Publication date: February 7, 2002Inventor: Koichi Sato
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Publication number: 20010052961Abstract: A liquid crystal display device comprises: a layer of a chiral liquid crystal material disposed between first and second substrates; and means for applying a voltage across the liquid crystal layer. A first region of the liquid crystal layer is an active region for display and a second region of the liquid crystal layer is a nucleation region for generating a desired liquid crystal state in the first region when a voltage is applied across the liquid crystal layer. The ratio of the thickness d of the liquid crystal layer to the pitch p of the liquid crystal material has a first value (d/p)A in the first region of the liquid crystal layer and has a second value (d/p)N different from the first value in the second region of the liquid crystal layer.Type: ApplicationFiled: February 6, 2001Publication date: December 20, 2001Inventors: Michael John Towler, Elizabeth Jane Acosta, Harry Garth Walton, Craig Tombling, Martin David Tillin, Brian Henley, Emma Jayne Walton, Tadashi Kawamura, Akiyoshi Fujii, Yuichiro Yamada
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Patent number: 6327017Abstract: A display device including two parallel transparent plates (10, 12) having transparent electrodes on the inner surfaces thereof and containing a liquid crystal material (20). The device includes means defining a monostable anchoring for each plate (10, 12), means (40) controllable to break at least one of the anchorings, and means for thereafter inducing volume bistability.Type: GrantFiled: September 14, 1998Date of Patent: December 4, 2001Assignee: Nemoptic S.A.Inventors: Ricardo Barberi, Ivan Dozov, Georges Durand, Philippe Martinot-Lagarde, Maurizio Nobili, Eric Polossat, Ioannis Lelidis, Michele Giocondo
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Patent number: 6281956Abstract: A liquid crystal display device includes a first substrate and a second substrate sandwiching a liquid crystal layer therebetween, a first polarizer disposed adjacent to the first substrate at a side opposite to a side of the first polarizer facing the liquid crystal layer, with a first gap between the first polarizer and the first substrate, a second polarizer disposed adjacent to the second substrate at a side opposite to a side of the second polarizer facing the liquid crystal layer, with a second gap between the second polarizer and the second substrate, wherein at least one of the first and second gaps includes therein a first retardation film having a positive optical anisotropy and a second retardation film having a negative optical anisotropy, such that the first retardation film is disposed closer to the liquid crystal layer with respect to the second retardation film.Type: GrantFiled: December 29, 1997Date of Patent: August 28, 2001Assignee: Fujitsu LimitedInventors: Katsufumi Ohmuro, Yoshio Koike, Takahiro Sasaki, Hideaki Tsuda, Hideo Chida
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Patent number: 6268839Abstract: A series of drive schemes are used to apply a single phase of at least one voltage pulse to drive a display with a bistable cholesteric liquid crystal material to a gray scale reflectance. Each drive scheme takes into consideration the initial texture of the cholesteric material and the range of voltages that may be applied between maximum and minimum reflectance of the material. Application of the single phase can be implemented by either time modulation or amplitude modulation.Type: GrantFiled: May 12, 1998Date of Patent: July 31, 2001Assignee: Kent State UniversityInventors: Deng-Ke Yang, Xiao-Yang Huang, Nick M. Miller
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Patent number: 6249332Abstract: A bistable nematic liquid crystal device cell (1) is provided with a surface alignment grating on at least one cell wall (3) and a surface treatment on the other wall (4). Such treatment may be a homeotropic alignment or a planar alignment with or without an alignment direction, and zero or a non zero pretilt. The surface profile on the monograting is asymmetric with its grove height to width selected to give approximately equal energy within nematic material (2) in its two allowed alignment arrangements. The monograting may be formed by a photolithographic process or by embossing of a plastics material. The cell (1) is switched by dc pulses coupling to a flexoelectric coefficient in the material (2), or by use of a two frequency addressing scheme and a suitable two frequency material. Polarizers (13,13′) either side of the cell (1) distinguish between the two switched states. The cell walls (3,4) may be rigid or flexible, and are coated with electrode structures (6,7), e.g.Type: GrantFiled: March 30, 1998Date of Patent: June 19, 2001Assignee: The Secretary of State for Defense in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventors: Guy Peter Bryan-Brown, Carl Vernon Brown, John Clifford Jones
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Patent number: 6233028Abstract: A plasma-addressed liquid crystal color display device comprising a layer of liquid crystal material, data electrodes coupled to the liquid crystal layer and adapted to receive data voltages for activating pixels of the liquid crystal layer, and a plurality of ionizable-gas-filled plasma channels extending generally transverse to the data electrodes for selectively switching on said liquid crystal pixels. The plasma channels are sealed off by a thin dielectric sheet. To reduce the magnitude of the data voltages needed to activate the device, the LC layers are given compositions such that a much higher fraction of the applied data voltages appears across the liquid crystal layer thereby allowing a smaller data voltage to be used to obtain the same effect on the liquid crystal pixels.Type: GrantFiled: October 22, 1997Date of Patent: May 15, 2001Assignee: U.S. Philips CorporationInventors: Jacob Bruinink, Frans Leenhouts
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Patent number: 6222605Abstract: A surface mode liquid crystal device is made by forming a cell containing a mixture of a liquid crystal and a pre-polymer. An electric field is applied across the cell to arrange the liquid crystal in a predetermined surface mode state, such as the V state in the case of a pi-cell configuration. The liquid crystal is held in this state by the field while the pre-polymer is polymerized or cross-linked, for instance by ultraviolet irradiation. The electric field is then removed. The polymer stabilizes the predetermined surface mode state, for instance preventing relaxation of the V state to twist or splay state in the pi-cell configuration.Type: GrantFiled: October 9, 1996Date of Patent: April 24, 2001Assignee: Sharp Kabushiki KaishaInventors: Martin David Tillin, Edward Peter Raynes, Michael John Towler
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Patent number: 6208403Abstract: An antiferroelectric liquid crystal display device includes: an active matrix type LC cell and an antiferroelectric liquid crystal sealed in the cell. Liquid crystal molecules aligned to one of a first aligning direction and a second aligning direction are aligned in the other aligning direction in accordance with an applied voltage, thus forming a plurality of regions of different alignment states in a range shorter than a wavelength of light in a visible light band, and directions of said directors are changed in accordance with a ratio of regions in a first alignment state to regions in a second alignment state. The liquid crystal molecules may behave along a predetermined cone by a phase transition precursor in accordance with an applied voltage. The liquid crystal molecules may behave so as to be inclined in a direction perpendicular to an electric field, in accordance with an applied voltage.Type: GrantFiled: April 24, 2000Date of Patent: March 27, 2001Assignee: Casio Computer Co., Ltd.Inventors: Tomio Tanaka, Tetsushi Yoshida, Jun Ogura, Satoru Shimoda
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Patent number: 6181403Abstract: A liquid-crystal electro-optical device is offered which can operate at high speeds and easily oriented. The value of the surface tension of liquid crystal-orienting layers is 40 dynes/cm or more, and these layers are rubbed in antiparallel directions to each other. This reduces the pretilt angle of the molecules of a nematic liquid crystal sandwiched between two substrates. The anisotropy of the dielectric constant of the nematic liquid crystal is positive.Type: GrantFiled: July 23, 1999Date of Patent: January 30, 2001Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Toshimitsu Konuma
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Patent number: 6115099Abstract: In order to provide a liquid crystal display device which uses a liquid crystal material having physical quantities set so as to contribute to high image quality by reducing crosstalk, flicker, and direct-current component shift, the liquid crystal material used in a liquid crystal display device according to the present invention has an effective dielectric constant .epsilon..sub.P in the direction of the long axis and an effective dielectric constant .epsilon..sub.V in the direction of the short axis which, if X=.epsilon..sub.P +.epsilon..sub.V and Y=.epsilon..sub.P .multidot..epsilon..sub.V, satisfy Y=A.multidot.X-B at a certain point in the ranges 9.5.ltoreq.X.ltoreq.15.5, 5.43.ltoreq.A.ltoreq.5.75, and 27.ltoreq.B.ltoreq.36.2.Type: GrantFiled: June 11, 1999Date of Patent: September 5, 2000Assignee: Sharp Kabushiki KaishaInventors: Tomohiko Yamamoto, Keiichi Tanaka, Naoto Inoue, Yutaka Ishii
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Patent number: 6061042Abstract: A liquid crystal display device includes a liquid crystal display cell having a layer of a twisted-nematic liquid crystal material with a positive dielectric anisotropy constant and constructed such that a plurality of voltage potentials applied to the liquid crystal cell may firstly induce a Freedricksz transition of the liquid crystal material and then select either one of first and second metastable states caused by relaxation of the liquid crystal material succeeding the Freedricksz transition. A first voltage potential is adjusted higher than a threshold voltage necessary to cause changes from an initial state to the metastable states, a second voltage potential to select one of the metastable states is adjusted in comparison with a voltage potential necessary to switch between the metastable states, and a third voltage potential is applied as a modulation voltage during or succeeding the application of the second voltage potential.Type: GrantFiled: February 6, 1998Date of Patent: May 9, 2000Assignee: Ricoh Company, Ltd.Inventors: Hiroyuki Takahashi, Kenji Kameyama, Yasuyuki Takiguchi, Akihiko Kanemoto, Fuminao Matsumoto, Kazuya Miyagaki
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Patent number: 6052168Abstract: Disclosed is an active matrix liquid-crystal display, which has: two transparent insulative substrates, either one of which having a plurality of scanning lines, a plurality of signal lines formed in the direction of intersecting with the plurality of scanning lines, a plurality of switching elements disposed on the intersection points of the plurality of scanning lines and the plurality of signal lines, and pixel electrodes connected to the plurality of switching elements; a liquid crystal sandwiched between the two transparent insulative substrates; polarizing plates disposed outside the two transparent insulative substrates; and linear opposing electrodes formed, through insulating film, under the pixel electrodes with a width greater than that of the pixel electrode; wherein the liquid crystal has positive permittivity anisotropy and is oriented nearly perpendicularly to the transparent insulative substrates, the pixel electrode is composed of single or a plurality of linear electrodes, and the directionType: GrantFiled: November 19, 1998Date of Patent: April 18, 2000Assignee: NEC CorporationInventors: Shinichi Nishida, Hiroaki Matsuyama
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Patent number: 6038001Abstract: A liquid crystal display device comprises a pair of substrates opposing each other, each having an electrode and an aligning film on an inner surface, a layer of bistable nematic liquid crystal sealed in a space between substrate, and two polarizing plates. A reset pulse voltage high enough to align the molecules almost vertically to the substrates is applied to the layer of liquid crystal. Then, a first state-selecting pulse voltage lower than the reset pulse voltage is applied between the electrodes, whereby the molecules of the liquid crystal assume a first metastable aligned state. Alternatively, a second state-selecting pulse voltage lower than the reset pulse voltage is applied between the electrodes, whereby the molecules of the liquid crystal assume a second metastable aligned state.Type: GrantFiled: August 12, 1997Date of Patent: March 14, 2000Assignee: Casio Computer Co., Ltd.Inventors: Toshiomi Ono, Tetsushi Yoshida, Toshihiro Mannoji
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Patent number: 6034755Abstract: A liquid crystal display comprises a liquid crystal cell of a bend alignment mode or a hybrid aligned nematic (HAN) mode, one or two optical compensatory sheets and one or two polarizing elements. The liquid crystal cell comprises liquid crystal molecules provided between two electrode substrates. The optical compensatory sheet comprises a transparent substrate and an optically anisotropic layer. The transparent substrate is optically anisotropic. The optically anisotropic layer contains a discotic compound. The liquid crystal cell, the optical compensatory sheet and the transparent substrate have optical characteristics satisfying the following formulas..vertline.(nx1-ny1).times.d1.vertline.-20.ltoreq..SIGMA..vertline.(nx2-ny2) .times.d2.vertline..ltoreq..vertline.(nx1-ny1).times.d1.vertline.+2050.ltoreq.{(n12+n22)/2-n32).times.d2.ltoreq.10000.ltoreq..vertline.(nx3-ny3).times.d3.vertline..ltoreq.200100.ltoreq.{(n13+n23)/2-n33).times.d3.ltoreq.1000The formulas are defined in the specification.Type: GrantFiled: January 22, 1999Date of Patent: March 7, 2000Assignee: Fuji Photo Film Co., Ltd.Inventor: Hidetoshi Watanabe
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Patent number: 6018378Abstract: A composition for use in a liquid crystal optical element, such as a liquid crystal display or laser shutter device, comprised of a liquid crystal material and a solidified polymer material. The liquid crystal is such that its refractive index is changed depending on states of applying a voltage. In one state, the refractive index of the liquid crystal substantially coincides with the refractive index of the solidified matrix to thereby pass light. While in the other state, the refractive index of the liquid crystal does not coincide with the refractive index of the solidified matrix to thereby cause the scattering of light. Specifically, the liquid crystal material used in the composition has a refractive index anisotropy (.DELTA.n) is greater than 0.18 and the dielectric anisotropy (.DELTA..epsilon.) satisfies the relation of 5<.DELTA..epsilon.<11.6.Type: GrantFiled: December 18, 1997Date of Patent: January 25, 2000Assignee: Asahi Glass Company, Ltd.Inventors: Yoshinori Hirai, Satoshi Niiyama, Tomoki Gunjima, Masanori Yuki, Masaya Kunigita, Yukio Yoshikawa, Eiji Shidoji
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Patent number: 6005646Abstract: A voltage application driving method is provided for quickly changing the alignment of a liquid crystal layer in thin film transistor liquid crystal displays (TFT/LCD) to a bend alignment. In this driving method, a potential difference larger than 10 V is continuously or intermittently provided between the signal electrode of the liquid crystal cells, and the counter electrode of the display while maintaining the potential difference between the gate electrode and the signal electrode of the cells larger than 10 V.Type: GrantFiled: December 22, 1997Date of Patent: December 21, 1999Assignee: International Business Machines CorporationInventors: Hajime Nakamura, Michikazu Noguchi
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Patent number: 5995173Abstract: The present invention relates to a display device based on liquid crystals, comprising a nematic liquid-crystal material (10) with positive dielectric anisotropy sandwiched between two transparent confinement plates (20, 30) each provided with transparent electrodes (22, 32), characterized in that at least one of the plates, (30), defines a quasi-bistable anchoring and in that it is provided with main electrical supply means (40) suitable for applying a temporary electric field to the liquid-crystal material (10) capable of breaking the anchoring on the aforementioned plate (30) and subsequently allowing, due to the effect of hydrodynamic instabilities, various localized orientations of the liquid-crystal molecules (10) corresponding to the preferred orientations of the quasi-bistable anchoring.Type: GrantFiled: November 8, 1996Date of Patent: November 30, 1999Assignee: Instituto Nationale per La Fisica Della MateriaInventors: Riccardo Barberi, Roberto Bartolino, Ivan Dozov, Georges Durand, Michele Giocondo, Jun Li
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Patent number: 5933203Abstract: Driver apparatus and methods of driving at least a portion of a cholesteric liquid crystal ("CLC") panel to a state having a given reflectivity. One of the methods includes the steps of: (1) initially driving the portion to a nematic phase, (2) subsequently driving the portion to a cholesteric phase focal-conic state, the cholesteric phase focal-conic state providing a known reference state for subsequent driving of the portion and (3) thereafter driving the portion to the state having the given reflectivity.Type: GrantFiled: January 8, 1997Date of Patent: August 3, 1999Assignee: Advanced Display Systems, Inc.Inventors: Bao-Gang Wu, Jianmi Gao, Meng Zhao
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Patent number: 5883686Abstract: The invention provides active-matrix display devices with non-linear two-pole switching elements such as MIMs or three-pole switching elements such as TFTs having a smaller difference in charge current at a different image content by using a suitable. ##EQU1## This leads to less burn-in of the image to be displayed. Moreover, a satisfactory transmission characteristic is obtained at a higher value of .epsilon..sub..perp.. For TFTs it is then possible to use smaller auxiliary capacitances due to the higher values of (.epsilon..sub..perp.). The latter aspect may in turn be utilized to realise a larger aperture.Type: GrantFiled: December 21, 1995Date of Patent: March 16, 1999Assignee: Flat Panel Display Co. (FDP) B. V.Inventors: Frans Leenhouts, Peter B.A. Wolfs
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Patent number: 5841489Abstract: In a spatial light modulator of the present invention, a photoconductive layer formed of photoconductive material receives write light having a spatial distribution in its intensity and changes resistivity of the photoconductive material dependently on the spatial distribution in the intensity of the received write light. A liquid crystal layer formed of liquid crystal molecules of nematic phase receives read light and presents birefringence with respect to the received read light. An electric voltage is applied through the photoconductive layer and the liquid crystal layer to thereby produce an electric field in the liquid crystal layer. The photoconductive layer changes the electric field produced in the liquid crystal layer in accordance with the resistivity of the photoconductive material so as to electrically control the birefringence of the liquid crystal molecules.Type: GrantFiled: July 30, 1993Date of Patent: November 24, 1998Assignee: Hamamatsu Photonics K.K.Inventors: Narihiro Yoshida, Naohisa Mukohzaka, Haruyoshi Toyoda, Terushige Hori, Yuji Kobayashi, Tsutomu Hara
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Patent number: 5805253Abstract: A liquid crystal display has a bend orientation cell or HAN mode cell and further is provided with an optical compensatory sheet. The optical compensatory sheet shows the minimum of absolute values of retardation values in a direction inclined from the normal of the sheet.Type: GrantFiled: November 18, 1996Date of Patent: September 8, 1998Assignee: Fuji Photo Film Co., Ltd.Inventors: Hiroyuki Mori, Yoji Ito
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Patent number: 5796459Abstract: A nematic liquid crystal device with two bistable switched states, having two cell walls treated which provide a bigrating on one or both cell walls. The bigrating enables the liquid crystal molecules at a surface to lie in two different angular directions, 45 or 90 degrees apart. The bigrating may be symmetric or asymmetric, with the surface energy of each of the gratings of the bigratings being nearly equal.Type: GrantFiled: September 20, 1996Date of Patent: August 18, 1998Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventors: Guy P. Bryan-Brown, Damien G. McDonnell, Michael J. Towler, Martin S. Bancroft
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Patent number: 5778625Abstract: A recessed lighting fixture includes a back housing which is secured to a form board for receiving poured concrete such that the concrete sets around the housing to form a recessed area in a concrete structure. The form board is joined to a stiffener plate to support the housing under the force of the concrete. The form board and stiffener plate are removed from the back housing and the internal components of the lighting fixture are disposed in and secured to the interior of the back housing to form a recessed lighting fixture which is flush with the surface of the structure, for example a concrete wall. The internal components of the fixture may subsequently be removed and replaced should the need arise as only the back housing is fixed to the concrete wall.Type: GrantFiled: October 11, 1996Date of Patent: July 14, 1998Assignee: Bega/US, Inc.Inventors: James B. Druffel, Larry L. Routh
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Patent number: 5745203Abstract: A liquid crystal display device (10) for forming a display includes a liquid crystal panel (12), a switchable holographic optical element (14), and a reflective holographic optical element (16). Ambient light illuminates a front polarizer (18), which polarizes the ambient light and transmits the polarized light to the liquid crystal cell (20). The liquid crystal cell (20) receives the polarized light and transmits polarized light derived from the incident polarized light to a back polarizer (22). The back polarizer (22) polarizes the light and transmits the light to the switchable holographic optical element (14). While in a first mode, the switchable holographic optical element (14) redirects the light back toward the liquid crystal panel (12) within a first viewing cone (34) to form the display. In a second mode, the switchable holographic optical element (14) is transparent and transmits the light to the reflective holographic optical element (16).Type: GrantFiled: March 28, 1996Date of Patent: April 28, 1998Assignee: Motorola, Inc.Inventors: George T. Valliath, Kevin W. Jelley, Alan G. Chen, Mark J. Johnson
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Patent number: 5707543Abstract: A reversible display medium capable of repeatedly exhibiting a transparent state and a light-scattering state by an action of at least one of heat, electric field, and magnetic field, the medium comprising a substrate having thereon a recording layer comprising a side-chain high molecular weight liquid crystal, which is a copolymer comprising at least a liquid-crystal monomer component and a non-liquid-crystal monomer component having a substituent capable of making a hydrogen bond.Type: GrantFiled: March 27, 1995Date of Patent: January 13, 1998Assignee: Fuji Xerox Co., Ltd.Inventors: Ryojiro Akashi, Takashi Morikawa, Masanobu Ninomiya, Takashi Uematsu
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Patent number: 5640259Abstract: A liquid crystal device includes a pair of substrates, a liquid crystal layer interposed between the pair of substrates, at least one polarizing element, and a plurality of pixels. A retardation (d.times..DELTA.n) of the liquid crystal layer satisfies the relation:d.times..DELTA.n>.lambda./2when incident light is output after passing through the liquid crystal layer once. The retardation satisfies the relation:2d.times..DELTA.n>.lambda./2when the incident light is output after passing through the liquid crystal layer twice. In these relations, d a thickness of the liquid crystal layer, .DELTA.n is a birefringence, and .lambda. is a wavelength of the light incident on the liquid crystal layer. A driving voltage supplier applies a driving voltage including a voltage higher than a maximum voltage providing an extremum of the output light intensity in a voltage-output light intensity characteristic of the pixels to the plurality of pixels.Type: GrantFiled: December 19, 1994Date of Patent: June 17, 1997Assignee: Sharp Kabushiki KaishaInventors: Yutaka Sawayama, Naofumi Kimura, Yoshitaka Yamamoto, Yutaka Ishii
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Patent number: 5619352Abstract: A twisted/splayed O-plate compensation device, in accordance with the invention, is comprised of an organic liquid crystal polymer thin film and possibly one or more other birefringent layers. The O-plate thin film is a birefringent medium with its optical symmetry axis, on average, oriented obliquely with the surface of the film. Within this constraint, the direction of the material's optical symmetry axis is allowed to vary continuously along the axis normal to the film surface. Such films may be fabricated by applying thin layers of chiral doped nematic or semectic liquid crystal monomer solutions in inert solvents to transparent substrates. The carrier solvents are then evaporated and the monomers polymerized by UV irradiation. Compensation devices may also be comprised of multiple layers of twisted/splayed O-plate material in conjunction with A-plates, C-plates, and simple O-plates. Fabrication techniques for twisted/splayed O-plates are described.Type: GrantFiled: July 31, 1996Date of Patent: April 8, 1997Assignee: Rockwell International CorporationInventors: Gene C. Koch, Bruce K. Winker, William J. Gunning, III
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Patent number: 5583679Abstract: Disclosed is an optical compensatory sheet which comprises a transparent support and an optically anisotropic layer provided thereon, wherein the optically anisotropic layer comprises a compound having a discotic structure unit in its molecule and has negative birefringence, and the discotic structure unit has a plane inclined from a plane of the transparent support at an angle varying along a direction of depth of the anisotropic layer. A liquid crystal display and a color liquid crystal display provided with the optical compensatory sheet are also disclosed.Type: GrantFiled: May 31, 1995Date of Patent: December 10, 1996Assignee: Fuji Photo Film Co., Ltd.Inventors: Yoji Ito, Yosuke Nishiura, Koh Kamada, Hiroyuki Mori, Taku Nakamura