Cholesteric Reflector Patents (Class 349/115)
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Patent number: 6735009Abstract: Electrooptic devices (100, 600, 700) include a left handed (102, 708) and right handed (104, 710) cholesteric phase liquid crystal layers. Electrodes (120, 122, 124, 126, 602, 604) or magnetic coils (704, 706) are used to apply electric or magnetic fields perpendicular to helical axes of the cholesteric phase liquid crystal layers. The fields lengthen the helical pitch of the liquid crystal layers thereby shifting the reflectance of the liquid crystal layers to longer wavelengths. Spectral reflectance of both left and right hand polarized light is controlled by the electrooptic devices.Type: GrantFiled: July 16, 2002Date of Patent: May 11, 2004Assignee: Motorola, Inc.Inventor: Zili Li
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Patent number: 6727967Abstract: A phase difference plate and a liquid-crystal layer are provided between a polarizing plate and a selective reflection layer formed of cholesteric liquid crystal. A first color filter layer is provided on the polarizing plate side of the selective reflection layer. On the back side of the selective reflection layer, a second color filter layer is arranged. On the back side of the second color filter layer, a backlight is provided. When a liquid-crystal display device functions as a reflective liquid-crystal display device, light entering through the polarizing plate is reflected totally by the selective reflection layer and passes through the first color filter layer twice. When the liquid-crystal display device functions as a transmission liquid-crystal display device, light from the backlight passes through the selective reflection layer. Then, the light passes through the second and first color filter layers once and is outputted.Type: GrantFiled: July 15, 2002Date of Patent: April 27, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Takashi Nakamura, Yoshinori Higuchi, Yuzo Hisatake
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Publication number: 20040075794Abstract: A cholesteric display may be formed, in some embodiments, using a single display element to produce multi-colors for display. A cholesteric material may be sandwiched between a pair of substrates, each associated with pairs of opposed electrodes that are arranged in general transversely to the optical axis of incident light. The first pair of electrodes produce one of two liquid crystal states and result in the reflection of light of a particular wavelength. Light of other wavelengths may be reflected when a second pair (or set) of opposed electrodes, arranged in general transversely, also to the optical axis of incident light, are biased appropriately. So does a third pair (or set) of electrodes. A black and white color display may be generated from a single display element by modulating the pitch length of the cholesteric material within each pairs (or sets).Type: ApplicationFiled: October 17, 2002Publication date: April 22, 2004Inventors: David B. Chung, Daniel J. Lenehan
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Patent number: 6724459Abstract: A reflective liquid crystal display includes upper and lower substrates that are opposite to and are spaced apart from each other; a liquid crystal layer interposed between the upper and lower substrates; a transparent common electrode on the surface of the upper substrate opposite the lower substrate; a cholesteric liquid crystal (CLC) color filter that selectively reflects and transmits light, the CLC color filter formed over the lower substrate; a transparent pixel electrode on the CLC color filter; and a light absorption layer between the lower substrate and the CLC color filter.Type: GrantFiled: June 29, 2001Date of Patent: April 20, 2004Assignee: LG. Philips LCD Co., Ltd.Inventor: Sunghoe Yoon
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Patent number: 6724446Abstract: There is provided an illuminator having a planar light source unit having reflectance of from 50 to 90% with respect to light in a state in which the light is emitted from a light source provided separately from the planar light source and incident on the planar light source unit, and a reflective type polarizer disposed on a light exit side of the planar light source unit so that a reflected light component and a transmitted light component of polarized light can be obtained from natural light incident on the reflective type polarizer. There is provided a liquid-crystal display device having an illuminator defined above, and a liquid-crystal display panel disposed on an upper side of the reflective type polarizer in the illuminator.Type: GrantFiled: February 8, 2002Date of Patent: April 20, 2004Assignee: Nitto Denko CorporationInventors: Hironori Motomura, Naoki Takahashi
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Patent number: 6717639Abstract: An array substrate for a reflective liquid crystal display can include a substrate, thin film elements formed on the substrate, and color filters formed on the thin film elements. Each of the color filters preferably include a cholesteric liquid crystal. A pixel electrode can be formed on each of the color filters so that the pixel electrode corresponds to a respective color filter.Type: GrantFiled: May 30, 2001Date of Patent: April 6, 2004Assignee: LG. Philips LCD Co. Ltd.Inventor: Jin Hee Jung
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Patent number: 6717640Abstract: The reflection-type liquid crystal display device includes two liquid crystal layers for selectively reflecting light in a specific wavelength range, and a partition wall interposed between the liquid crystal layers so as to separate the liquid crystal layers from each other. The partition wall serves as a scattering layer having a light scattering function.Type: GrantFiled: August 22, 2002Date of Patent: April 6, 2004Assignee: Sharp Kabushiki KaishaInventors: Eiji Sato, Yasuhisa Itoh, Kiyoshi Minoura, Tomoko Teranishi
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Publication number: 20040061819Abstract: Electro-optical glazing structures having total-reflection and semi-transparent and totally-transparent modes of operation which are electrically-switchable for use in dynamically controlling electromagnetic radiation flow in diverse applications.Type: ApplicationFiled: June 23, 2003Publication date: April 1, 2004Inventors: Sadeg M. Faris, Le Li
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Patent number: 6710823Abstract: Electro-optical glazing structures having total-reflection and semi-transparent and totally-transparent modes of operation which are electrically-switchable for use in dynamically controlling electromagnetic radiation flow in diverse applications.Type: GrantFiled: November 6, 2001Date of Patent: March 23, 2004Assignee: Reveo, Inc.Inventors: Sadeg M. Faris, Le Li, Jian-Feng Li
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Patent number: 6710831Abstract: A Liquid Crystal Display (LCD) uses a tunable mirror in place of a partially reflective mirror. The tunable mirror has a controllable reflectivity and transmitance which allows the mirror to primarily reflect light when the LCD is operated in a reflective mode, and to primarily transmit light from a backlight when the LCD is operated in a transmissive mode.Type: GrantFiled: September 29, 2000Date of Patent: March 23, 2004Assignee: Rockwell Scientific Licensing, LLCInventors: Bruce Winker, William J. Gunning
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Publication number: 20040051830Abstract: In view of the above problems of the prior art, the present invention has been made, and an object of the present invention is to provide a board, which is free from coloring, has high color tone quality, can realize a bright display screen, and imposes no significant restriction on the provision of an electric circuit, and a display device comprising the board, and further provides a liquid crystal display board, which is excellent in color contrast between transmission display and reflection display, and a semi-transmission color liquid crystal display device comprising the liquid crystal display board. A board according to the invention comprises a light transparent substrate and a cholesteric layer provided on the substrate and provided with an optical window of a predetermined pattern.Type: ApplicationFiled: July 7, 2003Publication date: March 18, 2004Inventor: Keiji Kashima
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Patent number: 6707519Abstract: A liquid crystal device of the present invention performs transmissive display using light from an illumination devices 111 and 112 in a dark environment, and reflective display using light reflected by a transflective layer 123 provided on the inner side of a liquid crystal cell in a bright environment. A retardation plate is provided adjacent to a polarizer 109 and an illumination device so that the rotational direction of polarization of the light emitted from the illumination device is the same as that of the polarization of the light reflected by the transflective layer in a dark display state.Type: GrantFiled: October 4, 1999Date of Patent: March 16, 2004Assignee: Seiko Epson CorporationInventors: Osamu Okumura, Tsuyoshi Maeda, Eiji Okamoto, Takumi Seki
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Patent number: 6697133Abstract: A light controlling film is described comprising a polymerized polymer network of a crosslinked high molecular weight polymeric material and a low molecular weight cholesteric liquid crystal (CLC) material, wherein the high molecular weight and the low molecular weight form a material having cholesteric liquid crystal (CLC) order such that the film is a reflective circular polarizer whose bandwidth is controllable by an electric field impressed in the film.Type: GrantFiled: April 8, 2002Date of Patent: February 24, 2004Assignee: Reveo, Inc.Inventors: Bunsen Fan, Jian-feng Li, Le Li, Sadeg Faris
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Patent number: 6697144Abstract: Switchable optical components such as switchable mirrors and variable retarders are fabricated using a unique class of materials. These materials are thin film composites comprising of porous inorganic films imbibed with liquid crystal materials.Type: GrantFiled: December 19, 2001Date of Patent: February 24, 2004Assignee: Agilent Technologies, Inc.Inventor: John C. Kralik
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Publication number: 20040032556Abstract: A reflective liquid crystal display device of the present invention includes: first and second substrates spaced apart from each other, the first and second substrates having sub-pixels; a liquid crystal layer interposed between the first and second substrates; a switching element and a pixel electrode on a rear surface of the second substrate, wherein the switching element and the pixel electrode are formed within a sub-pixel and electrically connected to each other; a retardation film and a polarizer formed in series on a front surface of the second substrate; a double-layered CCF on a front surface of the first substrate, the double-layered CCF including red, green and blue CLC color films in the sub-pixels that respectively reflect wavelengths of red, green and blue colored light so that the sub-pixels produce red, green and blue colors, respectively; and a common electrode on the double-layered CCF layer; wherein the double-layered CCF layer includes a first and second CLC layers, a first alignment layerType: ApplicationFiled: August 11, 2003Publication date: February 19, 2004Inventors: Sunghoe Yoon, Hee-Nam Hwang
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Patent number: 6693689Abstract: A reflective liquid crystal display includes a linear polarizer for converting natural light into linearly polarized light; a retardation film for converting the linearly polarized light into circularly polarized light; a liquid crystal layer for varying the phase of the light differently depending on the presence or absence of an electric field; a cholesteric liquid crystal color filter for selectively reflecting light received from the liquid crystal layer; and a black background for absorbing light passing through the color filter.Type: GrantFiled: March 28, 2000Date of Patent: February 17, 2004Assignee: LG Philips LCD Co., Ltd.Inventors: Yong Beom Kim, Soon Bum Kwon, Heume Il Baek
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Patent number: 6690439Abstract: A method of manufacturing cholesteric liquid crystal (CLC) color filters in which an alignment treatment is accomplished simultaneously with a coloring process during a light exposure process using ultraviolet ray. Photochromic CLC is used for the cholesteric liquid crystal (CLC) and a photosensitive alignment material is used for an alignment layer.Type: GrantFiled: December 26, 2001Date of Patent: February 10, 2004Assignee: LG. Philips LCD Co., Ltd.Inventors: Ji-Young Ahn, Jong-Weon Moon
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Patent number: 6680758Abstract: The present invention relates to beam steering and scanning devices which utilize cholesteric liquid crystal (CLC) elements arranged in branches to form a logic tree. Each branch comprises an active and passive CLC element; the former further comprising a half-wave retarder and an electrode and the latter only the CLC element. Each succeeding branch contains twice as many branches as a preceding branch and, by activating active CLC element electrodes under control of a programmable pulsed source, inputs applied to the first stage of a logic tree are delivered as a scanned line of electromagnetic energy or light to the imaging cells of the last stage of the logic tree. By stacking identical logic trees with a laser source for each tree, a flat panel imaging array or display device is formed in which the transmission losses are minimized.Type: GrantFiled: January 16, 1997Date of Patent: January 20, 2004Assignee: Reveo, Inc.Inventor: Sadeg Mustafa Faris
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Publication number: 20040008302Abstract: A liquid crystal display device includes: first and second substrates facing and spaced apart from each other; a retardation layer on an outer surface of the first substrate; a linear polarizing layer on the retardation layer; a cholesteric liquid crystal color filter (CCF) layer on an inner surface of the second substrate; a liquid crystal layer between the first substrate and the CCF layer; a first cholesteric liquid crystal (CLC) polarizing layer on an outer surface of the second substrate, the first CLC polarizing layer having a first helical pitch of a first circular polarization direction; a second cholesteric liquid crystal (CLC) polarizing layer on the first CLC layer, the second CLC polarizing layer having a second helical pitch of a second circular polarization direction opposite to the first circular polarization direction; and a backlight unit outside the second CLC layer.Type: ApplicationFiled: July 8, 2003Publication date: January 15, 2004Inventor: Jong-Weon Moon
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Publication number: 20040008301Abstract: A liquid crystal display device includes first and second substrates facing and spaced apart from each other; a first polarizing film on an outer surface of the first substrate; a liquid crystal layer between the first and second substrates; a backlight unit under the second substrate; and a cholesteric liquid crystal polarizing film between the second substrate and the backlight unit, the cholesteric liquid crystal polarizing film having a first portion adjacent to the backlight unit, a second portion adjacent to an outer surface of the second substrate and a third portion between the first and second portions, the first and second portions respectively having first and second pitches, the third portion having a third pitch having a value between the first and second pitches.Type: ApplicationFiled: June 27, 2003Publication date: January 15, 2004Inventor: Sunghoe Yoon
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Patent number: 6678024Abstract: A liquid crystal display device includes first and second substrates spaced apart from each other with a liquid crystal therebetween. The liquid crystal display device adopts a cholesteric liquid crystal color filter. Each portion of the cholesteric liquid crystal color filter is designed to have an adjusted order parameter according to a wavelength of a corresponding color ray. Therefore, with the variously adjusted order parameters of the cholesteric liquid crystal color filter, an increase of the color shift due to a longer wavelength is prevented.Type: GrantFiled: February 12, 2001Date of Patent: January 13, 2004Assignee: LG.Philips LCD Co. , Ltd.Inventor: Yong-Beom Kim
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Patent number: 6671016Abstract: A transmission-reflection type liquid crystal display device including a first transparent substrate and a second transparent substrate; a liquid crystal layer between the first transparent substrate and the second transparent substrate; a linear polarizer and a resinoid color filter provided on the second transparent substrate; a left-handed cholesteric liquid crystal circular polarizer provided on the first transparent substrate; and a left-handed cholesteric liquid crystal color filter formed on the first transparent substrate in order to be situated between the cholesteric liquid crystal circular polarizer and the liquid crystal layer. The liquid crystal display device having this structure can be driven as a reflection type and a transmission type display. The cholesteric liquid crystal color filter having good color purity is added to the resinoid color filter to improve the overall color properties of the device.Type: GrantFiled: June 2, 2000Date of Patent: December 30, 2003Assignee: LG Philips LCD Co., Ltd.Inventor: Yong Beom Kim
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Patent number: 6667794Abstract: A flat plate collimator and backlight system capable of improving the display characteristics of liquid crystal display devices are obtained. In order to achieve this end, a collimator is provided which comprises a cholesteric liquid crystal layer exhibiting a selective-reflection wavelength band with respect to perpendicularly-incident light in the wavelength range &lgr;1 to &lgr;2 (&lgr;1<&lgr;2), and which satisfies the relation &lgr;0<&lgr;1 with respect to the maximum-emission wavelength &lgr;0 in the emission spectrum of the light source with which the collimator is used in combination, and a backlight system employing this collimator and light source is provided.Type: GrantFiled: September 24, 2001Date of Patent: December 23, 2003Assignee: Fuji Photo Film Co., Ltd.Inventors: Kohei Arakawa, Fumihiko Mochizuki, Kenichi Nakagawa, Mitsuyoshi Ichihashi
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Patent number: 6667788Abstract: A liquid crystal panel has a cholesteric filter and the quarter wave plate inserted between a glass substrate and color filter elements, and each section of the cholesteric filter reflects either right-handed or left-handed circularly polarized light component recognized as one of the three primary colors and the circularly polarized light components recognized as other primary colors toward a light source so as to recycle these circularly polarized light components, thereby enhancing the utilization factor of incident light without increase of power consumption.Type: GrantFiled: June 14, 2000Date of Patent: December 23, 2003Assignee: NEC LCD Technologies, Ltd.Inventors: Muneo Maruyama, Eriko Fujimaki
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Publication number: 20030231266Abstract: This invention relates to paper white cholesteric displays employing a reflective elliptical polarizer. In the reflective mode, the paper white ON state is achieved by a reflective elliptical polarizer in display's planar texture area; and the black OFF state is obtained by cholesteric's depolarization effect and polarizer's filtration effect in display's focal conic texture area. In the transmissive mode, on the other hand, the paper white ON state is created by a back lighting projected onto the focal conic texture area; and the black OFF state is realized in the cholesteric planar texture area. The reflective elliptical polarizer with a broadband reflection and high polarization efficiency delivers a bright neutral white color to both the reflective and transmissive mode cholesteric displays. The reflective elliptical polarizer also provides a solution to the transflective display where the high efficiency front-lit mode and the back-lit mode can be converted automatically.Type: ApplicationFiled: June 17, 2002Publication date: December 18, 2003Inventor: Yao-Dong Ma
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Publication number: 20030231269Abstract: This invention relates to reflective cholesteric displays without using Bragg reflection. The helical pitch of the cholesteric liquid crystals may or may not be tuned in a visible wavelength, but its Bragg reflection will never be displayed. An elliptical polarizer with properly designed retardation and lamination positioned at the front of the display will be able to eliminate the Bragg reflection over a large viewing cone. The function of the display cell structure is merely a light shutter to switch the incident light ON and OFF. In the black-and-white display mode, the white state is achieved from the metal reflection in the cholesteric planar texture area; and the black state is obtained by cholesteric's depolarization effect and polarizer's filtration effect in the cholesteric focal conic texture area.Type: ApplicationFiled: June 15, 2002Publication date: December 18, 2003Inventor: Yao-Dong Ma
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Patent number: 6665031Abstract: A display device (1) comprising a light modulation panel (2), a first polarization layer (5), a first ¼&lgr; layer (6), a semi-transparent reflective layer (7), a lens (8), a second ¼&lgr; layer (11) and a second polarization layer (12). The first ¼&lgr; layer (6) is situated between the first polarization layer (5) and the semi-transparent reflective layer (7). The second polarization layer (12) is a reflective polarization layer. The display device may include a hologram.Type: GrantFiled: June 22, 2001Date of Patent: December 16, 2003Assignee: Koninklijke Philips Electronics N.V.Inventor: Wouter Roest
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Patent number: 6661487Abstract: A method of producing a laminated optical film constituted by a laminate of a plurality of optical films different in area, the method including the steps of: laminating an optical film (B) having a plurality of rectangular holes parallel to one another, on at least one surface of an optical film (A) to thereby form a laminate; and cutting the laminate into a plurality of chips to thereby obtain laminated optical films.Type: GrantFiled: June 5, 2002Date of Patent: December 9, 2003Assignees: Nitto Denko Corporation, Sharp Kabushiki KaishaInventors: Naoki Takahashi, Satoru Kawahara, Shoji Sugiura, Takeyuki Ashida, Takio Imai
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Patent number: 6661486Abstract: A reflector for reflecting a broad bandwidth of electromagnetic (EM) radiation, comprising a sheet comprising a large plurality of pairs of layers of transparent polymer material parallel to a surface of the sheet, each pair of layers having a difference in the index of refraction between the materials in each layer of the pair, the total thickness of each pair of layers in the large plurality of layers varying substantially continuously and non linearly across the thickness of the sheet, is disclosed.Type: GrantFiled: March 14, 1998Date of Patent: December 9, 2003Assignee: Reveo, Inc.Inventors: Sadeg Faris, Le Li
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Publication number: 20030218708Abstract: A wavelength-selective reflection film comprises at least one layer. In the layer, liquid crystal molecules are aligned in a chiral smectic phase. The chiral smectic phase has a helical pitch and an average refractive index. The product of the helical pitch and the average refractive index is in the range of 213 to 450 rm. The layer selectively reflects light in a particular wavelength range, and selectively transmits light in another wavelength range.Type: ApplicationFiled: May 21, 2003Publication date: November 27, 2003Applicant: FUJI PHOTO FILM CO., LTD.Inventor: Mitsuyoshi Ichihashi
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Patent number: 6654080Abstract: A liquid crystal display device includes cell wall structure and a chiral nematic liquid crystal material. The cell wall structure and the liquid crystal cooperate to form focal conic and twisted planar textures that are stable in the absence of a field. A device applies an electric field to the liquid crystal for transforming at least a portion of the material to at least one of the focal conic and twisted planar textures. The liquid crystal material has a pitch length effective to reflect radiation having a wavelength in both the visible and the infrared ranges of the electromagnetic spectrum at intensity that is sufficient for viewing by an observer. One liquid crystal material may be disposed in a single region or two or more liquid crystal materials may be used, each in separate regions even without the infrared reflecting layer. One aspect of the invention is directed to a photolithography method for patterning a substrate of the display.Type: GrantFiled: June 10, 1999Date of Patent: November 25, 2003Assignee: Kent Displays, Inc.Inventors: Asad A. Khan, Xiao-Yang Huang, Haiji Yuan, Minhua Lu
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Patent number: 6654081Abstract: There is provided an optical element having: a laminate including a reflective type polarizer for separating incident light into polarized light components through reflection and transmission, and a dichromatic polarizer, wherein a variation of hue between two points calculated by the expression: {(x2−x1)2+(y2−y1)2} is not larger than 0.06 when x1 and y1 express a hue at a point with a predetermined elevation angle and any azimuth angle, and x2 and y2 express a hue at another point with the same elevation angle and a changed azimuth angle in the case where transmitted light is obliquely viewed in the condition that the laminate is disposed on a planar light source so that the reflective type polarizer is located in an inner side. An illuminator having the above planar light source and laminate and including a reflection layers on its rear surface side, is disposed behind a liquid crystal cell.Type: GrantFiled: February 8, 2002Date of Patent: November 25, 2003Assignee: Nitto Denko CorporationInventors: Ikuo Kawamoto, Hironori Motomura, Naoki Takahashi
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Patent number: 6646710Abstract: A bright, and contrasty reflective display can be performed without using polarizer films, and display switching can be performed fast. A ferroelectric liquid crystal is sandwiched between substrates, and electrodes are formed face to face with each other in a direction parallel to the substrates. The ferroelectric liquid crystal, when no electric field is applied to it, goes into a planer state in which a helical axis becomes perpendicular to or almost perpendicular to the substrates, selectively reflecting light of specific wavelengths in a visible region. A driving circuit applies an electric field between the electrodes in a direction perpendicular to or almost perpendicular to the helical axis of the ferroelectric liquid crystal in the planer state.Type: GrantFiled: April 26, 2001Date of Patent: November 11, 2003Assignee: Fuji Xerox Co., Ltd.Inventors: Teiichi Suzuki, Takehito Hikichi, Shigeru Yamamoto, Naoki Hiji
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Publication number: 20030206259Abstract: To form a brightness enhancement film of cholesteric liquid crystal, a photopolymerizable liquid crystal is first formed on a first substrate. A second substrate then is formed on the liquid crystal substance to form a sandwich structure. The sandwich structure is subsequently submitted to a lamination process that generates shear stress thereon. Finally, an energetic irradiation including UV irradiation is performed to solidify the layer of liquid crystal into a liquid crystal polymer film. The second substrate then is selectively removed. The above steps are repeated until a desired reflected wavelength range of the liquid crystal film is obtained.Type: ApplicationFiled: September 10, 2002Publication date: November 6, 2003Applicant: Industrial Technology Research Inst.Inventors: Pao-Ju Hsieh, Hui-Lung Kuo, Ping-Yao Wu, Wen-Bing Chu
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Publication number: 20030206260Abstract: Disclosed is a liquid crystal display having stacked liquid crystal light modulation layers each containing a liquid crystal compound. At least one of the liquid crystal modulation layers is different from remaining ones in at least one of a dielectric anisotropy, a thickness, a liquid crystal compound contained therein, and a functional layer provided therein so that the drive voltage ranges for the layers are made equal.Type: ApplicationFiled: June 2, 2003Publication date: November 6, 2003Applicant: MINOLTA CO., LTDInventors: Nobuyuki Kobayashi, Masako Iwamatsu, Hideaki Ueda
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Publication number: 20030197820Abstract: A reflective-type multi-color display device is capable of obtaining a vivid and bright multi-color display with less display layers, and therefore, with a state where a parallax is decreased and a cost of the device can be reduced. Specifically, the display device of the present invention includes a cell 51 having a display layer 31 comprising a right-handed cholesteric liquid crystal which selects and reflects blue, a cell 53 having a display layer 33 comprising a left-handed cholesteric liquid crystal which selects and reflects green, a cell 57 having a display layer 37 comprising a right-handed cholesteric liquid crystal which selects and reflects yellow and a cell 55 having a display layer 35 comprising a left-handed cholesteric liquid crystal which selects and reflects red, these layers being laminated in this order from the observation side. A color filter 43 which transmits red and absorbs the other color light is provided between the cell 57 and the cell 55.Type: ApplicationFiled: May 9, 2003Publication date: October 23, 2003Applicant: FUJI XEROX CO., LTD.Inventors: Naoki Hiji, Shigeru Yamamoto, Takehito Hikichi, Teiichi Suzuki
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Patent number: 6636291Abstract: In a method of manufacturing a liquid crystal device including a layer having a fixed cholesteric order, the patterned layer is manufactured by providing a layer comprising polymerizable cholesterically ordered material and a compound convertible by means of radiation from a non-converted to converted state. The pitch of the cholesterically ordered material is influenced by the compound in its converted state to a different extent than in its converted state. The polymerizable layer is then irradiated pattern-wise thus creating regions of different pitch. The irradiated layer is then polymerized and/or cross-linked to fix the cholesteric order thus obtained.Type: GrantFiled: May 18, 2001Date of Patent: October 21, 2003Assignee: Koninklijke Philips Electronics N.V.Inventors: Peter Van De Witte, Michael Geoffrey Pitt
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Patent number: 6633354Abstract: A light controlling film is disclosed, comprising a polymerized polymer network varying spatially in a direction normal to the film surface, where the polymerized polymer network is a crosslinked high molecular weight polymeric material mixed with a low molecular weight nematic material exhibiting cholesteric liquid crystal (CLC) order, wherein an electric field impressed in the film controls the reflection bandwidth of circularly polarized light.Type: GrantFiled: June 7, 1999Date of Patent: October 14, 2003Assignee: Reveo, Inc.Inventors: Le Li, Bunsen Fan, Yingqiu Jiang, Sadeg M. Faris, Jian-Feng Li
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Patent number: 6630974Abstract: Cholesteric liquid crystal films using varying pitch helix structures aligned perpendicular to the surface of the film for broadband reflection and transmission of circularly polarized light distort the light at large viewing angles of incidence due to the elliptical cross section of the CLC helix with the light at large incident angles. By using compensating films of an infrared cholesteric liquid crystal to rotate the major axis of the elliptical light to ±45 degrees and a homeotropic film having elongated molecules with the long axis perpendicular to the surface of the film to convert the elliptically adjusted light from the IR CLC film to circularly polarized light, the distortions at large angles can be eliminated. The compensated light will be circularly polarized for large angles of incidence over a broad band.Type: GrantFiled: May 14, 1999Date of Patent: October 7, 2003Assignee: Reveo, Inc.Inventors: Hristina Galabova, Le Li
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Patent number: 6624858Abstract: A liquid crystal display panel for a timepiece comprises: a polymer dispersed liquid crystal cell (10) which is structured by respectively forming an opposed electrode (2) on a first substrate (1) of a pair of transparent substrates and a signal electrode (4) on a second substrate (3), and sealing a liquid crystal layer (5) containing a liquid crystal and a polymer material between the first substrate (1) and the second substrate (3) to form pixel portions at intersections between the signal electrode (4) and the opposed electrode (2); a reflector (15) which transmits a portion of light, placed on the side of a face, on which the opposed electrode (2) is not formed, of the first substrate (1); and an auxiliary light source placed on the outer side of the reflector (15), so that time information can be displayed with good visibility even when the auxiliary light source is turned off.Type: GrantFiled: January 31, 2000Date of Patent: September 23, 2003Assignee: Citizen Watch Co., Ltd.Inventors: Koji Nakagawa, Kanetaka Sekiguchi
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Publication number: 20030174268Abstract: A cholesteric display may be formed, in some embodiments, using a single display element to produce multi-colors for display. A cholesteric material may be sandwiched between a pair of substrates, each associated with a first pair of opposed electrodes that are arranged generally transversely to the optical axis of incident light. The first pair of electrodes produce one of two liquid crystal states and result in the reflection of light of a particular wavelength. Light of other wavelengths may be reflected when a second pair (or set) of opposed electrodes, arranged generally transversely to the first pair of electrodes, are biased appropriately. A color display may be generated from a single display element by modulating the pitch length of the cholesteric material.Type: ApplicationFiled: March 15, 2002Publication date: September 18, 2003Inventor: David B. Chung
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Patent number: 6621543Abstract: A transflective liquid crystal display device that can selectively be used in the transmissive mode or the reflective mode. The transflective liquid crystal panel includes a reflective electrode having a transparent portion, a CLC color filter and a CLC polarizer. Light from a backlight device can pass through the transparent portion of the reflective electrode and into the liquid crystal. Moreover, light from the backlight device that is reflected by the reflective electrode can also pass through the transparent portion and into the liquid crystal without being absorbed by the CLC polarizer. The brightness of the transflective LCD device is thus improved.Type: GrantFiled: January 8, 2001Date of Patent: September 16, 2003Assignee: LG.Philips LCD Co., Ltd.Inventor: Jong-Weon Moon
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Publication number: 20030164914Abstract: A multiple layer reflective polarizer 12 is described. This element is placed between and optical cavity 24 and an LCD module 16 to form an optical display. The reflective polarizer reflects some light into the optical cavity 24 where it is randomized and may ultimately emerge with the correct polarization to be transmitted out of the display.Type: ApplicationFiled: February 19, 2003Publication date: September 4, 2003Applicant: 3M Innovative Properties CompanyInventors: Michael F. Weber, Olester Benson, Sanford Cobb, James M. Jonza, Andrew J. Ouderkirk, David L. Wortman, Carl A. Stover
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Publication number: 20030160924Abstract: The invention relates to a liquid crystal display constructed such that the efficiency of utilization of light is improved by use of a cholesteric liquid crystal filter thereby ensuring color density enough to enable both the transmission type display and the reflection type display. The liquid crystal display comprises a liquid crystal display device comprising a liquid crystal layer 3 sandwiched between transparent substrates 1 and 2 and a voltage applying electrode and a driving circuit, an illumination light source 9, a circularly polarizing plate 10 and a circularly polarizing plate 11. A cholesteric liquid crystal filter 4 of the type semitransparent to light in all red, green and blue wavelength ranges is located on the illumination light-directing side of the liquid crystal layer 3.Type: ApplicationFiled: November 4, 2002Publication date: August 28, 2003Inventor: Keiji Kashima
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Publication number: 20030160923Abstract: The present invention relates to a liquid crystal display, more specifically, relates to a full color cholesteric display employing circularly polarized micro-color filter which is composed of polymeric cholesteric thin film. The display has a long time memory and excellent characteristics of brightness and contrast. A built-in cholesteric color filter structure provides a full color gamut of circular polarization. A cholesteric liquid crystal cell structure, as a circular polarization modulator, provides optical ON and OFF states respectively with its one texture as a circular polarizer and the other texture as a depolarizer. Both of those two textures are electric field controllable.Type: ApplicationFiled: February 19, 2002Publication date: August 28, 2003Inventor: Yao-Dong Ma
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Patent number: 6603523Abstract: A liquid crystal display device includes a pair of polarizing plates; a liquid crystal panel interposed between the pair of polarizing plates and including a liquid crystal layer having a pair of regions corresponding to each of pixels, alignment directions of liquid crystal molecules in the pair of regions being different by about 180 degrees from each other, the liquid crystal panel having a first slow axis; a first phase plate having a second slow axis which is horizontal to a surface thereof and perpendicular to the first slow axis; and a second phase plate having a third slow axis which is perpendicular to both of the first slow axis and the second slow axis. The liquid crystal material has a dependency of birefringence anisotropy (&Dgr;n) from 20° C. to 60° C. ([&Dgr;n(20° C.)−&Dgr;n(60° C.)]/40) of 0.00026 or less.Type: GrantFiled: August 30, 2001Date of Patent: August 5, 2003Assignee: Sharp Kabushiki KaishaInventors: Masako Nakamura, Makoto Shiomi, Yoshito Hashimoto
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Publication number: 20030142256Abstract: The invention provides a thin reflective plate having cholesteric liquid crystal that can prevent or reduce a decrease of reflection efficiency. A reflective plate includes a cholesteric liquid crystal layer, and the cholesteric liquid crystal layer includes a plurality of regions in which the helical axes of the cholesteric liquid crystal are aligned in different directions in the plane of a substrate, and therefore, the regions can reflect color light components having different wavelengths. Consequently, the cholesteric liquid crystal layer can reflect light formed of light components of different colors (for example, white light) as a whole. When the reflective plate is applied to a reflective liquid crystal display device or the like, it is possible to appropriately reflect white light for display.Type: ApplicationFiled: January 27, 2003Publication date: July 31, 2003Applicant: SEIKO EPSON CORPORATIONInventors: Tsuyoshi Maeda, Kimitaka Kamijo, Kinya Ozawa, Hitoshi Tsuchiya
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Patent number: 6600527Abstract: The invention concerns a display assembly including two superposed, respectively upper (24) and lower (26) display devices, characterised in that the upper display device (24) includes a double structure formed of a display cell (28) arranged above an optical valve (30), said double structure being arranged so that said cell (28) and said valve (30) are transparent in a first state to make the lower display device visible (26), and that the cell (28) displays an item of data and that the valve (30) is opaque and masks at least partially the lower display device (26) in a second state, control means being provided for supplying a control voltage to the cell (28) and the optical valve (30) to cause them to switch from the first state to the second state and vice versa.Type: GrantFiled: June 16, 2000Date of Patent: July 29, 2003Assignee: Asulab S.A.Inventors: Naci Basturk, Joachim Grupp, Beat Gilomen
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Publication number: 20030128319Abstract: To provide a reflector using cholesteric liquid crystals arranged in a structure for reducing thickness, and a transflective liquid crystal display device including the reflector.Type: ApplicationFiled: December 6, 2002Publication date: July 10, 2003Applicant: SEIKO EPSON CORPORATIONInventor: Tsuyoshi Maeda
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Publication number: 20030112392Abstract: A liquid crystal display device having a cholesteric liquid crystal (CLC) color filter comprises a first substrate, a circular polarizer on the first substrate, a cholesteric liquid crystal (CLC) color filter on the circular polarizer, a first electrode on the cholesteric liquid crystal (CLC) color filter, a second substrate spaced apart from the first substrate, a second electrode beneath the second substrate, a liquid crystal layer between the first and second electrodes, a back light under the first substrate, a diffusive film on the second substrate, a retardation layer on the diffusive film, and a linear polarizer on the retardation layer.Type: ApplicationFiled: December 18, 2002Publication date: June 19, 2003Inventors: Jong-Weon Moon, Ji-Yong Kim, Sunghoe Yoon, Hee-Nam Hwang