Within Cholesteric Phase Patents (Class 349/175)
  • Publication number: 20110019132
    Abstract: A cholesteric liquid crystal display device includes: a plurality of pixel units arranged two-dimensionally between two transparent substrates. Each of the plurality of pixel units includes a cholesteric liquid crystal layer having a single-layer structure. The cholesteric liquid crystal layer includes: a liquid crystal molecule; a chiral dopant; and an optically polymerizable polymer. The chiral dopant is mixed with the liquid crystal molecule to form a cholesteric phase and has a solubility that varies with respect to the liquid crystal molecule according to temperature. The optically polymerizable polymer is cured to fix a helix pitch of the cholesteric phase.
    Type: Application
    Filed: March 12, 2010
    Publication date: January 27, 2011
    Inventors: Jae-eun Jang, Jae-eun Jung, Kyu-young Hwang, Jae-hoon Kim, Kwang-soo Bae
  • Patent number: 7859622
    Abstract: The present invention provides a retardation layer capable of effectively restraining the display quality deterioration without generating a bright and dark pattern in the display image even when a retardation layer is disposed in between a liquid crystal cell and a polarizing plate. The retardation layer comprises a plurality of minute units (domains) having molecular structure of cholesteric structure. Moreover, in the retardation layer, the helical pitch of the molecular structure is adjusted such that the selective reflected wavelength of the selected reflected light deriving from the molecular structure is shorter than the wavelength of the incident light on the retardation layer.
    Type: Grant
    Filed: March 30, 2010
    Date of Patent: December 28, 2010
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Keiji Kashima, Takashi Kuroda
  • Patent number: 7830479
    Abstract: The liquid crystal display includes a first display unit, a second display unit, a light absorbing layer disposed on a bottom surface of the first display unit so as to absorb light which has entered the first display unit through a top surface thereof and which has been transmitted by the first liquid crystal, and a control circuit section for effecting a switch between a two-surface display mode in which the second display unit is lapped over the first display unit so as to face the bottom surface thereof with the light absorbing layer interposed between them to display images independent of each other on the first display unit and the second display unit and a high image quality mode in which the second display unit is lapped over the first display unit so as to face the top surface thereof to display the same image on the first and second display units.
    Type: Grant
    Filed: September 1, 2009
    Date of Patent: November 9, 2010
    Assignee: Fujitsu Limited
    Inventor: Masaki Nose
  • Patent number: 7749575
    Abstract: The invention relates to a liquid crystal display utilizing a vertically aligned state of liquid crystal molecules when no voltage is applied and to a method of manufacturing the same. The invention is aimed at providing a liquid crystal display and a method of manufacturing the same in which the existing step for forming vertical alignment films can be omitted to achieve a cost reduction. The liquid crystal display includes a monofunctional monomer having a structure expressed by X-R (where X represents an acrylate group or a methacrylate group, and R represents an organic group having a steroid skeleton). A liquid crystal material is sandwiched between substrates which is then irradiated with ultraviolet rays to cure the monofunctional monomer, thereby forming a polymer film at an interface of a substrate. The monofunctional monomer has a hydrophobic skeleton such as an alkyl chain and a photoreactive group on one side of the skeleton.
    Type: Grant
    Filed: March 25, 2004
    Date of Patent: July 6, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shingo Kataoka, Hideaki Tsuda, Katsufumi Ohmuro, Jin Hirosawa, Seiji Tanuma, Yoshio Koike
  • Patent number: 7742136
    Abstract: A sheet with anti-counterfeit functions for making counterfeiting highly difficult in the case where authentication information is recorded using the properties of cholesteric liquid crystal is provided. A cholesteric liquid crystal layer 110 having a selective reflected wavelength band in at least the visible light region is provided in such a manner that this cholesteric liquid crystal layer 110 is a single layer of which thickness is approximately uniform, and an authentication region 112 of which selective reflected wavelength band is different is provided in at least one place. Preferably, an adhesive layer 130 is provided on one side of the cholesteric liquid crystal layer 110. Preferably, a base 120 is provided between the cholesteric liquid crystal layer 110 and the adhesive layer 130. Preferably, a light absorbing layer 140 is provided on adhesive layer 130 of the cholesteric liquid crystal layer 110.
    Type: Grant
    Filed: November 17, 2005
    Date of Patent: June 22, 2010
    Assignee: Nitto Denko Corporation
    Inventors: Seiji Umemoto, Miki Shiraogawa, Takahiro Fukuoka, Naoki Takahashi, Kentarou Takeda
  • Patent number: 7728949
    Abstract: Embodiments of the present invention relate to a cholesteric liquid crystalline material which may be usable in an electro-active element for providing fail safe operation, polarization insensitivity, low electrical power consumption requirements, and a small number of electrical connections. The cholesteric liquid crystalline material may be usable in an electro-active element for providing a diffractive efficiency or focusing efficiency above 90% in an activated state of the electro-active element and a diffractive efficiency or focusing efficiency below 10% in a deactivated state of the electro-active element.
    Type: Grant
    Filed: January 22, 2008
    Date of Patent: June 1, 2010
    Assignee: PixelOptics, Inc.
    Inventors: Roger Clarke, Allan Carmichael, Joshua N. Haddock, William Kokonaski
  • Publication number: 20100026450
    Abstract: An identification medium is to be observed via a linearly polarizing filter and includes a first liquid crystal layer that changes the wavelength of light according to the rotational angle of the linearly polarizing filter, a cholesteric liquid crystal layer, and a light absorbing layer that is provided below the cholesteric liquid crystal layer.
    Type: Application
    Filed: October 18, 2007
    Publication date: February 4, 2010
    Applicants: NHK SPRING CO., LTD., NIPPON OIL CORPORATION
    Inventors: Hidekazu Hoshino, Itsuo Takeuchi, Tokio Sakauchi, Suzushi Nishimura, Gorou Suzaki
  • Patent number: 7652736
    Abstract: An infrared light reflecting article is disclosed and includes a visible light transparent substrate including a polymer and an infrared light reflecting cholesteric liquid crystal layer disposed on the substrate. The substrate and infrared light reflecting cholesteric liquid crystal layer have a combined haze value of less than 3%.
    Type: Grant
    Filed: October 25, 2005
    Date of Patent: January 26, 2010
    Assignee: 3M Innovative Properties Company
    Inventors: Raghunath Padiyath, Marc D. Radcliffe, Cristina U. Thomas, Charles A. Marttila, Manish Jain, Michael F. Weber, Feng Bai
  • Publication number: 20090279023
    Abstract: A liquid crystal cell (5) comprises a layer (4) of cholesteric liquid crystal material; and a retarder (3) disposed in an optical path through the layer (4) of cholesteric liquid crystal material. The cholesteric liquid crystal material is switchable between a first state in which it cooperates with the retarder (3) to provide a first viewing angle range and a second state in which it cooperates with the retarder (3) to provide a second viewing angle range which is smaller than the first viewing angle range. The pitch of the cholesteric liquid crystal material is greater than an intended wavelength of operation of the liquid crystal cell divided by the average refractive index of the liquid crystal material. The liquid crystal cell may be used as a Viewing Angle Restriction (VAR) element, to enable another component, such as a display panel (6), to be operated in either a wide viewing mode or a narrow viewing mode.
    Type: Application
    Filed: July 3, 2007
    Publication date: November 12, 2009
    Inventors: Nathan J. Smith, Paul A. Gass, James M. Ball, Martin D. Tillin, Michel Sagardoyburu
  • Patent number: 7616287
    Abstract: A liquid crystal display element according to the present invention includes one or more sets of combinations of a pair of substrates, a liquid crystal layer composed of a liquid crystal composition indicating a cholesteric phase and disposed between the pair of substrates, and at least one layer of insulating thin film to insulate the liquid crystal layer from an electrode, wherein: the insulating thin film has an electrostatic capacity of not more than 10 ?F; the liquid crystal layer has a layer thickness in the range of 2 to 5 ?m; and the liquid crystal composition has a dielectric anisotropy in the range of 20 to 50. The present invention can realize at least one of lowered driving voltage, enlarged operating temperature range, decrease in electric power consumption and wide display maintaining temperature range, in a liquid crystal display element having a semi-permanent display maintaining function (memory function).
    Type: Grant
    Filed: August 21, 2007
    Date of Patent: November 10, 2009
    Assignee: Fujitsu Limited
    Inventors: Masaki Nose, Junji Tomita
  • Patent number: 7595856
    Abstract: 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: Grant
    Filed: April 11, 2005
    Date of Patent: September 29, 2009
    Assignee: Intel Corporation
    Inventors: David B. Chung, Daniel J. Lenehan
  • Patent number: 7593079
    Abstract: An optical element of the invention comprises at least three laminated circular-polarization-type-reflection polarizers (a) whose wavelength bands for selective reflection of polarized light overlap one another; a layer (b1) which is placed between at least a pair of the circular-polarization-type-reflection polarizers (a) and has a front retardation of substantially zero (in the normal direction) and a retardation of at least ?/8 with respect to incident light inclined by at least 30° relative to the normal direction; and a layer (b2) which is placed between at least another pair of the circular-polarization-type-reflection polarizers (a) and has a front retardation of substantially zero (in the normal direction) and a retardation of at most ?/2 with respect to incident light inclined by 60° relative to the normal direction.
    Type: Grant
    Filed: April 15, 2004
    Date of Patent: September 22, 2009
    Assignee: Nitto Denko Corporation
    Inventors: Kentarou Takeda, Naoki Takahashi, Kazutaka Hara, Takahiro Fukuoka
  • Patent number: 7575787
    Abstract: The invention has an object to provide a liquid crystal composite capable of sufficiently reducing the scattering of light in a focal conic state, a liquid crystal display element excellent in improvements of a color balance and a contrast, and electronic paper using the same. The content of a chiral material is higher in a cholesteric liquid crystal LCg for G than in a cholesteric liquid crystal LCb for B, and is higher in a cholesteric liquid crystal LCr for R than in the cholesteric liquid crystal LCg for G. The cholesteric liquid crystal LCr for R is prepared by mixing about 5 wt % of a chiral material CHl1 of an L-form with a base liquid crystal of an R-form, which contains 27 wt % of CHr1 of the R-form exhibiting a liquid crystallizability for a nematic liquid crystal LCn, and 3 wt % of a chiral material CHr2 of the R-form exhibiting no crystallizability.
    Type: Grant
    Filed: December 31, 2007
    Date of Patent: August 18, 2009
    Assignee: Fujitsu Limited
    Inventors: Masaki Nose, Junji Tomita, Yoshihisa Kurosaki
  • Patent number: 7576829
    Abstract: Presents a liquid crystal display device that does not require a surface orientation treatment, dramatically improves the response rate of dynamic image displays and does not experience light leaks when the display is black, which means to yield a dark field of vision. The liquid crystal display device comprises polymer-stabilized blue phase liquid crystals sandwiched between a pair of clear substrates. The liquid crystal display device obtained using polymer-stabilized blue phase liquid crystals exhibits large double refraction changes when an electrical field is applied in an in-plane direction to the cell substrates. The polymer-stabilized blue phases liquid crystals comprises a low molecular weight liquid crystal that allows a blue phase to appear between cholesteric and isotropic phases and polymer network formed in the low molecular weight liquid crystals.
    Type: Grant
    Filed: March 15, 2005
    Date of Patent: August 18, 2009
    Assignee: Japan Science and Technology Agency
    Inventors: Hirotsugu Kikuchi, Tisato Kajiyama, Toshihiko Nagamura, Yoshiaki Hisakado
  • Patent number: 7564518
    Abstract: This invention relates to a high brightness and high contrast ratio reflective cholesteric displays employing circular polarizers. The front circular polarizer has a predetermined polarity that is opposite both to the Bragg reflection of the display and to the back reflective circular polarizer. An absorptive weak polarizer with high transmittance is adopted in the display system. In the black-and-white display mode, the white state is achieved in the cholesteric focal conic texture area; and the black state is obtained in the cholesteric planar texture area. In the full color mode, the full color state is created by the micro-color filter in the cholesteric focal conic texture area; and the black state is realized in the cholesteric planar texture area.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: July 21, 2009
    Inventor: Yao-Dong Ma
  • Patent number: 7511776
    Abstract: 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 [?m] of the light modulating layer, the cell thickness d [?m], the twist angle n of liquid crystal molecules, and the interelectrode interval L [?m] are set in ranges of 1?p?15, 1?d?10, n?300°, and L<25.
    Type: Grant
    Filed: December 16, 2003
    Date of Patent: March 31, 2009
    Inventors: Takeshi Nishi, Rumo Satake, Yoshiharu Hirakata
  • Patent number: 7499125
    Abstract: In a preparation method, a chiral or cholesteric liquid crystal, a photoreactive monomer, and a photoinitiator are disposed in a liquid crystal cell. A principal surface of the liquid crystal cell is illuminated with ultraviolet light selected to have a non-uniform ultraviolet light intensity profile in the liquid crystal cell. The illuminating cooperates with the photoinitiator to polymerize at least a portion of the photoreactive monomer near the principal surface to generate a polymer network having a density corresponding to the non-uniform ultraviolet light intensity profile. The polymer network biases the liquid crystal toward a selected helical alignment direction. In some embodiments, the illuminating includes illuminating with first and second ultraviolet light intensity profiles to produce surface and volume polymer network components.
    Type: Grant
    Filed: March 1, 2006
    Date of Patent: March 3, 2009
    Assignees: Kent State University, Lachezar Komitov
    Inventors: Lachezar Komitov, Liang-Chy Chien, Sang Hwa Kim
  • Patent number: 7391546
    Abstract: A discrimination medium 10a includes a first double layered body 101 having a right-handed circular polarization polymer cholesteric liquid crystal layer 11 and a left-handed circular polarization polymer cholesteric liquid crystal layer 12 which are stacked. The right-handed circular polarization polymer cholesteric liquid crystal layer 11 reflects a specific right-handed circular polarization light, and the left-handed circular polarization polymer cholesteric liquid crystal layer 12 reflects a specific left-handed circular polarization light. The discrimination medium 10a is applied to the article 30, and is viewed via a simple determination tool 20 having a filter 21 allowing only right-handed circular polarization light to pass therethough and a filter 22 allowing only left-handed circular polarization light to pass therethough.
    Type: Grant
    Filed: May 14, 2004
    Date of Patent: June 24, 2008
    Assignee: NHK Spring Co., Ltd.
    Inventors: Hidekazu Hoshino, Itsuo Takeuchi
  • Patent number: 7382424
    Abstract: A display sheet comprising a substrate carrying layers of material; including a polymer-dispersed chiral-nematic liquid-crystal layer having a first high reflection state within the visible light spectrum and a second less-reflective state in said spectrum, said states being changeable by an electric field, which states can be maintained in the absence of an electric field; a first transparent conductor disposed over said polymer-dispersed chiral-nematic liquid-crystal layer; and a second conductor, wherein said imaging layer is substantially a monolayer of said domains comprises a mixture of at least two differently reflecting liquid crystal materials, in which the ? maximums of the two materials are separated by 100 to 250 nm.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: June 3, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Krishnan Chari, Charles M. Rankin, Jr.
  • Patent number: 7352422
    Abstract: Provided herein is a retardation optical element 10 that produces no bright and dark fringes on a displayed image even when placed between a liquid crystal cell 104 and a polarizer 102B and thus can effectively prevent lowering of display quality. The retardation optical element 10 includes a retardation layer 12 having a cholesteric-regular molecular structure with liquid crystalline molecules in planar orientation. The helical pitch in the molecular structure of the retardation layer 12 is so adjusted that the retardation layer 12 can, owing to its molecular structure, selectively reflect light whose wavelength falls in a range different from the wave range of light incident on the retardation layer 12 (the selective reflection wave range of the retardation layer is either shorter or longer than the wave range of the incident light).
    Type: Grant
    Filed: March 5, 2007
    Date of Patent: April 1, 2008
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventor: Keiji Kashima
  • Patent number: 7333166
    Abstract: The present invention relates to a display comprising a substrate, a patterned conductor, and a liquid crystal material having cleared areas and electrically writeable areas. The invention also relates to a method for making a display comprising providing a substrate having a patterned conductor thereon, applying a non-cleared liquid crystal material to the substrate, clearing the non-cleared liquid crystal material to produce a cleared liquid crystal material, applying a field to the patterned conductor to produce an image comprised of areas of cleared liquid crystal material and electrically writeable areas of crystal material.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: February 19, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Stanley W. Stephenson, III, Terry J. Martin
  • Patent number: 7298442
    Abstract: An optical body includes a) first particles comprising a first cholesteric liquid crystal material and b) a second cholesteric liquid crystal material. The first particles and the second cholesteric liquid crystal material form a structure where the first cholesteric liquid crystal material has a pitch that is different than the second cholesteric liquid crystal material. In one example, the second cholesteric liquid crystal material is in the form of second particles. In another example, the first particles are dispersed in a matrix of the second cholesteric liquid crystal material. In other examples, the optical body has more than one layer. In addition, one or more additional cholesteric liquid crystal materials can be used in the optical body. These optical bodies can be used as a reflective polarizer and can be used in a display.
    Type: Grant
    Filed: February 24, 2005
    Date of Patent: November 20, 2007
    Assignee: 3M Innovative Properties Company
    Inventors: Christopher C. Bowley, Ikuko Ebihara, Gregory Edward Gilligan, Richard John Pokorny, Marc Dudley Radcliffe, Prabhakara Satyauolu Rao, Philip Edwin Watson
  • Patent number: 7295278
    Abstract: 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: Grant
    Filed: March 15, 2002
    Date of Patent: November 13, 2007
    Assignee: Intel Corporation
    Inventor: David B. Chung
  • Patent number: 7286111
    Abstract: A display writer for writing on a light writable display of the type having a layer of cholesteric liquid crystal material disposed between two conductors, the cholesteric liquid crystal material having multiple stable optical states at zero electrical field; and a light absorber for forming an image wise thermal pattern in the cholesteric liquid crystal sufficient to change the optical state of the cholesteric liquid crystal in response to an image wise pattern of light, the display writer including a flash lamp; a reflective light modulator for modulating light from the flash lamp an image wise pattern; optics for directing the image wise modulated light onto the light writable display; and means for applying an electrical field to the conductors of the display in conjunction with activation of the flash lamp.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: October 23, 2007
    Assignee: Eastman Kodak Company
    Inventor: Stanley W. Stephenson, III
  • Patent number: 7277141
    Abstract: An optical body includes a substrate and a cholesteric liquid crystal layer disposed on the substrate. The cholesteric liquid crystal layer has a non-uniform pitch along a thickness direction of the layer and comprises a crosslinked polymer material that substantially fixes the cholesteric liquid crystal layer. The crosslinking hinders diffusion of cholesteric liquid crystal material within the cholesteric liquid crystal layer. In other methods of making an optical body, a reservoir of chiral material is provided during the process over a first cholesteric liquid crystal layer to diffuse into the layer and provide a non-uniform pitch. Alternatively, two coating compositions can be disposed on a substrate where the material of the first coating composition is not substantially soluble in the second coating composition.
    Type: Grant
    Filed: May 31, 2005
    Date of Patent: October 2, 2007
    Assignee: 3M Innovative Properties Company
    Inventors: Richard J. Pokorny, Marc D. Radcliffe, Philip E. Watson, Christopher C. Bowley, Ikuko Ebihara
  • Patent number: 7265810
    Abstract: The present invention provides a liquid crystal display device having uniform alignment of monostable ferroelectric liquid crystal, and a manufacturing method of the liquid crystal display device. The temperature range of a cholesteric phase or a chiral nematic phase of the phase sequence of the liquid crystal has a temperature width of not less than 3° C. After heating the liquid crystal to an isotropic phase once, the liquid crystal is cooled to room temperature (25° C.) at a cooling rate of 3, 5, 10° C./minute. An alignment treatment is performed by application of a DC voltage of not lower than 3 V, which is a sufficient voltage to obtain the effects of the alignment treatment, within a temperature range of ±3° C. from transition temperature at which the liquid crystal changes from the cholesteric phase to the chiral smectic C phase.
    Type: Grant
    Filed: July 17, 2003
    Date of Patent: September 4, 2007
    Assignee: Fujitsu Limited
    Inventor: Toshiaki Yoshihara
  • Patent number: 7202926
    Abstract: Provided herein is a retardation optical element 10 that produces no bright and dark fringes on a displayed image even when placed between a liquid crystal cell 104 and a polarizer 102B and thus can effectively prevent lowering of display quality. The retardation optical element 10 includes a retardation layer 12 having a cholesteric-regular molecular structure with liquid crystalline molecules in planar orientation. The helical pitch in the molecular structure of the retardation layer 12 is so adjusted that the retardation layer 12 can, owing to its molecular structure, selectively reflect light whose wavelength falls in a range different from the wave range of light incident on the retardation layer 12 (the selective reflection wave range of the retardation layer is either shorter or longer than the wave range of the incident light).
    Type: Grant
    Filed: June 26, 2003
    Date of Patent: April 10, 2007
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventor: Keiji Kashima
  • Patent number: 7148946
    Abstract: An optical device including a laminate of cholesteric liquid-crystal layers in which the wavelength ranges of selective reflection of circularly polarized light beams are out of visible light region and which are combined so that circularly polarized light beams transmitted through the cholesteric liquid-crystal layers to be left-handed and right-handed are inverted to each other. A liquid-crystal display apparatus including a vertically aligned liquid-crystal cell, polarizers disposed on opposite surfaces of the liquid-crystal cell, and one or two optical devices defined above and interposed between the liquid-crystal cell and either or each of the polarizers.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: December 12, 2006
    Assignee: Nitto Denko Corporation
    Inventors: Shuuji Yano, Yuuichi Nishikouji
  • Patent number: 7068344
    Abstract: The method of making an optical body includes coating a mixture that includes a plurality of cholesteric liquid crystal compositions, and a solvent on a substrate. Each cholesteric liquid crystal composition is different. A plurality of layers is formed on the substrate. Each layer includes a majority of one of the cholesteric liquid crystal compositions.
    Type: Grant
    Filed: February 24, 2003
    Date of Patent: June 27, 2006
    Assignee: 3M Innovative Properties Company
    Inventors: Richard J. Pokorny, Marc D. Radcliffe, Steven D. Solomonson, Terence D. Spawn
  • Patent number: 7061559
    Abstract: 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: Grant
    Filed: September 22, 2003
    Date of Patent: June 13, 2006
    Assignee: Kent Displays, Inc.
    Inventors: Asad A. Khan, Xiao-Yang Huang, Haiji Yuan, Minhua Lu
  • Patent number: 7038743
    Abstract: An electro-optic device includes a liquid crystal cell (10, 10?) and at least one electrode (40, 42, 40?, 42?) arranged to selectively electrically bias the liquid crystal cell (10, 10?). A chiral or cholesteric liquid crystal (30, 30?) is disposed in the liquid crystal cell (10, 10?). The liquid crystal (10, 10?) has an optic axis substantially along a selected optic axis direction in the absence of an electrical bias. A polymeric network (32, 32?, 72) is disposed at an inside surface of the liquid crystal cell (10, 10?). The polymeric network (32, 32?, 72) extends partway into the liquid crystal cell (10, 10?) leaving at least a portion of the liquid crystal cell (10, 10?) substantially free of the polymeric network (32, 32?, 72).
    Type: Grant
    Filed: January 28, 2004
    Date of Patent: May 2, 2006
    Assignees: Kent State University, Ecsibeo AB
    Inventors: Lachezar Komitov, Liang-Chy Chien, Sang Hwa Kim
  • Patent number: 7033653
    Abstract: The invention relates to a birefringent marking comprising a liquid crystal material. The invention further relates to method of providing such a birefringent marking and to the use of the birefringent marking for decorative or security applications.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: April 25, 2006
    Assignee: Merck Patent GmbH
    Inventors: Matthias Kuntz, Robert Hammond-Smith, Rodney Riddle, John Patrick, Donald Graham
  • Patent number: 7030949
    Abstract: A wavelength-selecting optical element includes a cholesteric layer that reflects or transmits either of a right-handed circularly polarized light component and a left-handed circularly polarized light component in a selected wavelength band of an incident light; and a diffusing layer disposed on the exit side of the cholesteric layer to diffuse the circularly polarized light component reflected or transmitted by the cholesteric layer. The cholesteric layer may be a color filter having a red, a green and a blue pixel region for each of pixels. Each of the pixel regions reflects or transmits either of a right-handed circularly polarized light component and a left-handed circularly polarized light component in a selected wavelength band of an incident light.
    Type: Grant
    Filed: May 29, 2002
    Date of Patent: April 18, 2006
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventor: Keiji Kashima
  • Patent number: 6989875
    Abstract: A liquid crystal display device includes a liquid crystal cell having a cholesteric liquid crystal color filter; an integrated collimating polarizer under the liquid crystal cell, the integrated collimating polarizer having a collimating layer and a circular polarizer on the collimating layer; a backlight under the integrated collimating polarizer; a diffusing layer over the liquid crystal cell; a retardation layer over the diffusing layer; and a linear polarizer over the retardation layer.
    Type: Grant
    Filed: May 6, 2004
    Date of Patent: January 24, 2006
    Assignee: LG.Philips LCD Co., Ltd.
    Inventor: Sunghoe Yoon
  • Patent number: 6947114
    Abstract: A liquid crystal light modulation element is provided that includes a liquid crystal layer held between a pair of substrates. The liquid crystal layer includes a liquid crystal material that exhibits a cholesteric phase and has a plurality of domains. The liquid crystal layer includes regions where the helical axes of the liquid crystal molecules in a focal conic state extend in regular directions within a plane that is substantially parallel to the surface substrate.
    Type: Grant
    Filed: July 29, 2004
    Date of Patent: September 20, 2005
    Assignee: Minolta Co., Ltd.
    Inventors: Jun Yamada, Masakazu Okada, Kiyofumi Hashimoto, Mitsuyoshi Miyai
  • Patent number: 6937305
    Abstract: A cholesteric liquid crystal (CLC) color filter layer for reflective LCD device includes an additional blue CLC color filter in the red and/or green CLC color filter to increase a color temperature. Since the additional blue CLC color filter is formed using ultraviolet light when forming the blue CLC color filter, additional manufacturing processes for the additional blue CLC color filter are not required. Furthermore, since the color temperature of output light increases according to the CLC color filter layer of the present invention, the high resolution is obtained in image display. Alternatively, the color temperature can be adjustable by way of forming an additional red and/or green CLC color filter in the blue CLC color filter.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: August 30, 2005
    Assignee: LG.Philips LCD Co., Ltd.
    Inventor: Joun-Ho Lee
  • Patent number: 6924873
    Abstract: The objective of the present invention is to provide a liquid crystal display device for displaying colors by transmission and reflection modes and a method for producing such devices, whereby the additive color mixing can be used, the structure is simplified, the driving-voltage is lower, the contrast is higher, the response speed is higher, and the screen can be larger. This objective can be achieved by a method including the following steps: mixing 0.001 to 20 wt % of dichromatic melanotic pigment into chiral nematic liquid crystal mixed with chiral dopant; preparing a mixture of the liquid crystal and prepolymer to be polymerized into transparent polymeric solid; inserting the mixture into the space between two conductive substrates, wherein at least one of which is transparent; and irradiating ultra-violet light or neighboring short-wavelength light onto the mixture.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: August 2, 2005
    Inventor: Tadahiro Asada
  • Patent number: 6917399
    Abstract: An optical body includes a substrate and a cholesteric liquid crystal layer disposed on the substrate. The cholesteric liquid crystal layer has a non-uniform pitch along a thickness direction of the layer and comprises a crosslinked polymer material that substantially fixes the cholesteric liquid crystal layer. The crosslinking hinders diffusion of cholesteric liquid crystal material within the cholesteric liquid crystal layer. In other methods of making an optical body, a reservoir of chiral material is provided during the process over a first cholesteric liquid crystal layer to diffuse into the layer and provide a non-uniform pitch. Alternatively, two coating compositions can be disposed on a substrate where the material of the first coating composition is not substantially soluble in the second coating composition.
    Type: Grant
    Filed: February 22, 2001
    Date of Patent: July 12, 2005
    Assignee: 3M Innovative Properties Company
    Inventors: Richard John Pokorny, Marc Dudley Radcliffe, Philip Edwin Watson, Christopher Chadwick Bowley, Ikuko Ebihara
  • Patent number: 6900469
    Abstract: Disclosed is a liquid crystal display apparatus comprising a pair of substrates and a liquid crystal layer provided between the substrates, the liquid crystal layer containing a liquid crystal composition that exhibits a cholesteric phase. The liquid crystal composition contains a mixture of a chiral material and nematic liquid crystal. The liquid crystal display layer is configured to satisfies the following conditions: a viscosity a [cP] of the liquid crystal composition is in a range from 30 to 150; a dielectric anisotropy b of the liquid crystal composition is in a range from 5 to 50; a thickness c [?m] of the liquid crystal layer is in a range from 3 to 8; and a product of a, b, and c is not less than 3500.
    Type: Grant
    Filed: September 19, 2001
    Date of Patent: May 31, 2005
    Assignee: Minolta Co., Ltd.
    Inventors: Takeshi Kitahora, Akihito Hisamitsu, Hideaki Ueda, Mitsuyo Matsumoto
  • Patent number: 6897906
    Abstract: A method of recording rewritable time related information on a label, includes the steps of providing an electrically rewritable label associated with an article which includes a plurality of rewritable segments, each such segment having a layer including a material which is effective in at least first and second optical states so that the time related information can be written, rewritten and viewed, wherein such time related information relates to usage or potential usage of the article or a device associated with the article and such time related information can be electrically changed by providing appropriate electrical fields to the material, and electrically addressing selected segments to write or rewrite appropriate time related information.
    Type: Grant
    Filed: March 26, 2002
    Date of Patent: May 24, 2005
    Assignee: Eastman Kodak Company
    Inventor: Stanley W. Stephenson
  • Patent number: 6888607
    Abstract: Rewritable signs (100, 1300) that include bistable cholesteric liquid crystal layers (102, 1402, 1404, 1406) are provided. According to one embodiment a rewritable sign (100) is devoid of circuitry for establishing electric fields in localize regions for writing information to the rewritable sign (100), and is consequently inexpensive. In the latter embodiment, a separate information writer (400) that includes an array of pixel electrodes (404) that is driven by an active matrix (602) is used to write information on the rewritable sign. According to another embodiment a rewritable sign (1300) includes three cholesteric liquid layers (1402, 1404, 1406) each of which reflects a different primary color. The three cholesteric liquid crystal layers (1402, 1404, 1406) are interleaved with sets of conductive lines (1316, 1320, 1322, 1324) that are used to apply signals to the cholesteric liquid crystal layers (1402, 1404, 1406) for the purpose of writing information.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: May 3, 2005
    Assignee: Motorola, Inc.
    Inventors: Bobby Dean Landreth, Steven D. Pratt, Robert W. Pennisi, Ronald J. Kelley, Sivakumar Muthuswamy, David S. Fredley
  • Patent number: 6885409
    Abstract: A display system includes a display arranged to receive an image wise pattern of light to form an image, including, a pair of conductors, at least one conductor being transparent, a layer of cholesteric liquid crystal material disposed between the conductors, the liquid crystal material having multiple stable optical states at zero electrical field, and a light absorber for forming an image wise thermal pattern in the liquid crystal sufficient to change the optical state of the cholesteric liquid crystal in response to an image wise pattern of light; a display writer, including, a light source for producing a flash of light of sufficient intensity to generate sufficient heat in the light absorber to change the optical state of the cholesteric liquid crystal, a mask located between the light source and the display for defining the image wise pattern of light, a display drive connectable to the conductors for generating an electric field between the conductors for changing the optical state of the cholesteric l
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: April 26, 2005
    Assignee: Eastman Kodak Company
    Inventors: Stanley W. Stephenson, Xiang-Dong Mi, David M. Johnson
  • Patent number: 6882401
    Abstract: A light modulation medium comprises a light modulation element having a pair of substrates and plural light modulation layers arranged between the substrates to form a multilayer structure and made of cholesteric liquid crystal adapted to change the liquid crystal orientation in response to application of a predetermined electric field, in which the ratio of the threshold electric field at which the liquid crystal orientation is moved from a planar state to a focal conic state of a first light modulation layer of the light modulation element to that of a second light modulation layer is not less than 0.3 and the ratio of the dielectric constant in a planar state of liquid crystal orientation of the first light modulation layer to that of the second light modulation layer is not less than 4.
    Type: Grant
    Filed: July 8, 2003
    Date of Patent: April 19, 2005
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Haruo Harada, Hiroshi Arisawa
  • Patent number: 6879362
    Abstract: The present invention provides a cholesteric liquid crystal color filter including partition walls that are formed at pixel boundaries, produced by: forming a liquid crystal layer comprising a cholesteric liquid crystal composition including at least a liquid crystal compound, a photoreactive chiral agent and a polymerization initiator; and irradiating the liquid crystal layer with UV light having wavelengths to which the polymerization initiator is photosensitive through a photomask to form the partition walls at areas corresponding to the pixel boundaries while the liquid crystal layer is in an isotropic liquid state or in a cholesteric state not exhibiting selective reflection of light in the visible range. The invention also provides a process for producing a cholesteric liquid crystal color filter including openings that are formed at positions corresponding to at least contact holes and/or electrode lead-out portions.
    Type: Grant
    Filed: August 21, 2002
    Date of Patent: April 12, 2005
    Assignee: Fuji Photo Film Co., Ltd.
    Inventor: Kouya Kawabata
  • Patent number: 6856086
    Abstract: A display includes a front panel and a back panel with a light control material in between. One of the panels includes a rigid substrate, for example made of glass or rigid plastic. The other of the panels includes a flexible substrate, for example made of a flexible plastic film. The panel with the flexible substrate may be made by a roll-to-roll process, with various fabrication operations formed while the flexible substrate is still part of a web of material. The panel with the rigid substrate may be separately fabricated, then combined with the other panel on the web through a pick and place operation that accurately locates the front panel relative to the back panel. The display may be any of a variety of displays, such as liquid crystal displays (LCDs), and electroluminescent displays, such as polymer light emitting devices (PLEDs) and organic light emitting devices (OLEDs).
    Type: Grant
    Filed: September 24, 2001
    Date of Patent: February 15, 2005
    Assignee: Avery Dennison Corporation
    Inventors: Anthony J. Grace, Kieran F. Drain, Yukihiko Sasaki
  • Patent number: 6853412
    Abstract: A transaction card having machine readable information and a visible display comprising: a card body; machine readable information on the card body; and a flexible display affixed to the card body for displaying information related to the machine readable information, the display including a pressure-insensitive polymer-dispersed cholesteric liquid crystal material having a first planar reflective state and a second transparent focal conic state, which is responsive to an applied voltage to display information wherein said information persists when the voltage is removed, and an array of conductors connected to the display for applying selected voltages from an external display driver to the display to change the state of the display.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: February 8, 2005
    Assignee: Eastman Kodak Company
    Inventor: Stanley W. Stephenson
  • Patent number: 6852375
    Abstract: The present invention is based on a chiral nematic liquid crystal composition which shows cholesteric liquid crystal phase and be able to reflect light in visible region selectively, comprising: a nematic liquid crystal material; a first chiral material with shift direction of selective reflection wavelength toward long wavelength direction depending on temperature; and a second chiral material with shift direction of selective reflection wavelength toward short wavelength direction depending on temperature; wherein at least one chiral material between the first chiral material and the second chiral material comprises two or more chiral compounds, and relates to a preparation method of the above chiral nematic liquid crystal composition and a (layered-type) liquid crystal display using the same.
    Type: Grant
    Filed: March 21, 2003
    Date of Patent: February 8, 2005
    Assignee: Minolta Co., Ltd.
    Inventors: Nobuyuki Kobayashi, Noboru Ueda, Hideaki Ueda
  • Publication number: 20040201816
    Abstract: A method and structure for broadening cholesteric liquid crystals spectrum are described. An electrode structure is added on a side of cholesteric liquid crystals, for producing a fringe field which is perpendicular to a screw axis of the cholesteric liquid crystal. Hence, the thread pitches of cholesteric liquid crystals near the electrode structure are lengthened, but the other thread pitches of cholesteric liquid crystals far from the electrode structure remain the same. Besides, light having appropriate wavelength is used to congeal the cholesteric liquid crystals having a polymeric characteristic, so that the cholesteric liquid crystals have varied thread pitches while no voltage is applied to the electrode structure. Therefore, the spectrum of cholesteric liquid crystals and applications thereof are widened.
    Type: Application
    Filed: April 8, 2004
    Publication date: October 14, 2004
    Inventors: Yu-Wen Chen, Chuen-Ru Lee, Szu-Fen Chen, Sheng-Shiung Hou
  • Patent number: 6801263
    Abstract: A liquid crystal display apparatus is provided that includes a liquid crystal display device having two polarizing filter arranged on opposite sides of a light modulating unit. The liquid crystal display apparatus also includes a back light on the back side of the liquid crystal display device, two eye polarizing filters fixedly mounted on the back light, an infrared LED arranged on the front side of the liquid crystal display device for illuminating the light on the head of a viewer, and light receiving devices deposed at a present spacing from the front sides of the two eye polarizing filter unit. Moreover, the liquid crystal display apparatus includes a position control unit for processing and comparing the volumes of the light by the light receiving devices to control the position of the back light in the left-and-right direction.
    Type: Grant
    Filed: December 7, 2001
    Date of Patent: October 5, 2004
    Assignee: Sony Corporation
    Inventors: Seiji Sato, Hidehiko Sekizawa
  • Patent number: 6781666
    Abstract: 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: Grant
    Filed: June 2, 2003
    Date of Patent: August 24, 2004
    Assignee: Minolta Co., Ltd.
    Inventors: Nobuyuki Kobayashi, Masako Iwamatsu, Hideaki Ueda