For Driving Grandjean To Focal Conic Or Dynamic Scattering Type Liquid Crystal Patents (Class 349/35)
  • Patent number: 10310349
    Abstract: A non-polarizer based variable light attenuating device includes a guest-host solution having a liquid crystal host and a guest dichroic dye disposed between first and second conducting layers provided on first and second transparent substrates. The guest-host solution has a low-haze while the guest dye orientation alters between a low light transmitting orientation and a high light transmitting orientation in response to a first voltage supplied to the first and second conducting layers. In response to a second voltage supplied to the first and second conducting layers, the guest-host solution changes to a focal conic light scattering orientation to achieve a high-haze translucent state.
    Type: Grant
    Filed: July 21, 2015
    Date of Patent: June 4, 2019
    Assignee: ALPHAMICRON INCORPORATED
    Inventors: Bahman Taheri, Tamas Kosa, Christine Baker, Volodymyr Bodnar
  • Patent number: 9915825
    Abstract: An apparatus for use in replicating an image associated with an input-pupil to an output-pupil includes a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler. The input-coupler couples light corresponding to the image into the bulk-substrate and towards the intermediate-component. The intermediate-component performs horizontal or vertical pupil expansion and directs the light corresponding to the image towards the output-coupler. The output-coupler performs the other one of horizontal or vertical pupil expansion and couples light corresponding to the image, which travels from the input-coupler to the output-coupler, out of the waveguide. The apparatus further includes a volume layer, embedded between first and second major planar surfaces of the bulk-substrate, configured to cause light that is output by the output-coupler to have a more uniform intensity distribution compared to if the volume layer were absent.
    Type: Grant
    Filed: November 10, 2015
    Date of Patent: March 13, 2018
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Steven John Robbins, Scott Woltman, R. Andrew Wall, Yarn Chee Poon
  • Patent number: 9130097
    Abstract: A solar powered variable light attenuating device includes a liquid crystal cell, a photovoltaic cell in electrical communication with the liquid crystal cell, and a light concentrator having a light absorbing surface and a light emitting surface optically coupled to the photovoltaic cell. At least a portion of light impinging on the light absorbing surface of the light concentrator is concentrated and directed through the light emitting surface to a photon-absorbing portion of the photovoltaic cell to generate a voltage. The generated voltage is used to change the liquid crystal cell from a de-energized state to an energized state in response to sunlight directed toward the photovoltaic cell.
    Type: Grant
    Filed: April 26, 2010
    Date of Patent: September 8, 2015
    Assignee: ALPHAMICRON INCORPORATED
    Inventors: Bahman Taheri, Tamas Kosa, Christine Martincic, Volodymyr Bodnar
  • Patent number: 8913215
    Abstract: A bistable switchable liquid crystal device is provided in which the device can be switched between a transparent and an opaque state by a predetermined voltage pulse. The device is based on polymer stabilized cholesteric materials. No additional amount of voltage has to be applied to the device in order to sustain the optical states. Therefore, the device is energy-saving.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: December 16, 2014
    Assignee: Kent State University
    Inventors: Deng-Ke Yang, Lei Shi, Rui Bao
  • Publication number: 20130342775
    Abstract: The present invention relates to a high scattering smectic liquid crystal material and display device using the same. In the present invention, a series of smectic A phase liquid crystals having compact arrangement of crystal domains or a series of smectic liquid crystal mixed materials having a degree of order higher than that of the smectic A phase and an optical texture different from that of the smectic A phase are obtained by mixing a smectic liquid crystal with an organic compound having a high optical anisotropy (?n) or mixing different types of smectic phases. When used in a smectic stable state liquid crystal display pattern, these materials have high scattering properties and can effectively improve the contrast of a smectic liquid crystal display device. The present invention also improves contrast when it used in a reflective smectic liquid crystal display device.
    Type: Application
    Filed: December 30, 2011
    Publication date: December 26, 2013
    Inventors: Gang Sun, Wenlei Li, Huan Yin
  • Publication number: 20130286309
    Abstract: A variable focal length achromatic lens includes a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping points. The refractive lens includes a fluid chamber with a flat glass surface and an opposing elastic polydimethylsiloxane (PDMS) membrane surface. Inserting fluid volume through a pump system into the clear aperture region alters the membrane curvature and adjusts the refractive lens' focal position. Primary chromatic aberration is remarkably reduced through the coupling of the fluidic and diffractive lenses at a number of selected focal lengths.
    Type: Application
    Filed: April 4, 2013
    Publication date: October 31, 2013
    Inventor: The Arizona Board of Regents on Behalf of the University of Arizona
  • Patent number: 8411006
    Abstract: In a display device having a plurality of scan signal line driving circuits, its display quality is improved. The display device comprises a plurality of scan signal lines, a plurality of image signal lines, and a plurality of scan signal line driving circuits for generating scan signals for driving the scan signal lines. Each of the scan signal line driving circuit internally generates a driving signal having the waveform of such potential variation that the potential decreases with a slope from a high potential to an intermediate potential between the high potential and a low potential. Each of the scan signal line driving circuits further includes a signal wiring for connecting the scan signal line driving circuits to one another and applying the driving signal.
    Type: Grant
    Filed: September 5, 2006
    Date of Patent: April 2, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Toshihiro Yanagi, Kazuhiro Tani
  • Patent number: 8325283
    Abstract: A recording device includes: a voltage application unit that applies a voltage exceeding a first threshold value to a display medium; a photosensitive layer in which an impedance changes depending on an irradiated light; and a light irradiation unit that irradiates light of a first intensity that changes the impedance of the display medium at the approximately same time as when the voltage is applied by the voltage application unit and, and when the voltage is no longer applied by the voltage application unit, irradiates light that has a second intensity lower than the first intensity and that damps the residual voltage to the second threshold value or below within a length of time equal to or less than the third threshold value.
    Type: Grant
    Filed: November 2, 2009
    Date of Patent: December 4, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Atsushi Hirano, Taijyu Gan, Haruo Harada, Takashi Morikawa, Chisato Urano, Yasunori Okano, Hiroshi Arisawa
  • Publication number: 20100194728
    Abstract: A cholesteric liquid crystal display device in which a first step for applying a high voltage pulse to initialize a pixel and a second step for applying a low voltage pulse to increase a coexistence ratio of a focal conic state to the planar state in the initialized pixel are performed and a gradation value is determined by a cumulative time during which the low voltage pulse is applied, the device includes: a voltage generation circuit; and a driver circuit, wherein: the voltage generation circuit includes: a step-up part that generates a step-up voltage from a power source voltage; a voltage switching part; and a voltage stabilization part that generates the predetermined voltage in accordance with the voltage control signal from the step-up voltage, wherein the voltage stabilization part suppresses variations in output voltage; and the step-up part switches step-up ratios between the first step and the second step.
    Type: Application
    Filed: April 5, 2010
    Publication date: August 5, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Tomohisa Shingai
  • Publication number: 20090316060
    Abstract: A conducting film or device electrode includes a substrate and two transparent or semitransparent conductive layers separated by a transparent or semitransparent intervening layer. The intervening layer includes electrically conductive pathways between the first and second conductive layers to help reduce interfacial reflections occurring between particular layers in devices incorporating the conducting film or electrode.
    Type: Application
    Filed: June 18, 2008
    Publication date: December 24, 2009
    Inventors: Manoj Nirmal, Stephen P. Maki, Jason C. Radel, Robert L. Brott, Donald J. McClure, Bright I Clark
  • Patent number: 7629953
    Abstract: An OCB-mode liquid crystal device includes a plurality of pixel electrodes arranged in a matrix on one substrate of a pair of substrates, and transferring an aligned state of liquid crystal sandwiched between the pair of substrates from spray alignment in an initial state to bend alignment to perform display. During the transfer, a voltage application operation of applying an equal voltage to a plurality of pixel electrodes corresponding to an arbitrary first row, and of applying, to two pixel electrodes adjacent to both sides of one arbitrary pixel electrode among a plurality of pixel electrodes in a second row adjacent to the first row in a column direction, both voltages which are higher than or lower than an applied voltage to the one pixel electrode is performed on at least some of the plurality of pixel electrodes arrayed in a matrix.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: December 8, 2009
    Assignee: Seiko Epson Corporation
    Inventor: Kosuke Fukui
  • Publication number: 20090290078
    Abstract: A bistable switchable liquid crystal device is provided in which the device can be switched between a transparent and an opaque state by a predetermined voltage pulse. The device is based on polymer stabilized cholesteric materials. No additional amount of voltage has to be applied to the device in order to sustain the optical states. Therefore, the device is energy-saving.
    Type: Application
    Filed: March 24, 2009
    Publication date: November 26, 2009
    Applicant: KENT STATE UNIVERSITY
    Inventors: Deng-Ke YANG, Lei SHI, Rui BAO
  • Publication number: 20090244413
    Abstract: A semitransparent display (100), suitable for use with an electronic device (700), is provided. The semitransparent display (100), in one embodiment, includes a cholesteric liquid crystal display layer (101) and a translucent electroluminescent layer (102), such as an organic light emitting diode device. Control circuitry (109) is coupled to each layer, and is configured to selectively actuate each layer. The cholesteric liquid crystal display layer (101) can be operated in any of a planar mode (201), a focal conic mode (202), or a homeotropic mode (203). Segments of the cholesteric liquid crystal display layer (101) can be selectively actuated so as to hide and reveal user actuation targets. Capacitive sensors (621,622) can be included so that the semitransparent display (100) works as a touch sensitive user interface. A user can see an object, such as a hand (105) or stylus, from above the semitransparent display (100) when the hand (105) or stylus is placed beneath the semitransparent display (100).
    Type: Application
    Filed: March 28, 2008
    Publication date: October 1, 2009
    Inventors: Tomohiro Ishikawa, Thomas Gitzinger
  • Publication number: 20090225244
    Abstract: An image display device comprises a display panel, a backlight module, a light path modifying device, and a switchable diffuser. The backlight module is to emit light as the display light source of the display panel. The light path modifying device is disposed between the display panel and the backlight module for changing the light path of the light to generate the first display mode in coordination with the display panel. The switchable diffuser is disposed between the light path modifying device and the display panel, and is capable of switching between a transparent mode and a scattering mode. The display device displays the first display mode in the transparent mode and displays the second display mode in the scattering mode.
    Type: Application
    Filed: March 6, 2009
    Publication date: September 10, 2009
    Inventors: Wen-Chun Wang, Chun-Chia Liu
  • Publication number: 20090161034
    Abstract: In a cholesteric liquid crystal display device (24), to drive a surface-stabilized layer of cholesteric liquid crystal material into the focal conic state, there is applied drive signal comprising a series of pulses (30, 34, 35, 36, 37, 38, 41). At least one initial pulse has sufficient energy to drive the layer of cholesteric liquid crystal material into the homeotropic state and the subsequent pulses have time-averaged energies which reduce to a minimum level at which the layer of cholesteric liquid crystal material is driven into the focal conic state. This produces a focal conic state of particularly low reflectance, which allows a high contrast ratio to be achieved.
    Type: Application
    Filed: June 14, 2005
    Publication date: June 25, 2009
    Inventors: David Coates, Amir Ben Shalom, Shlomit Angel-Devir, Christopher John Hughes
  • Publication number: 20090153757
    Abstract: The invention relates to a liquid crystal display element for displaying an image by driving a liquid crystal and provides a liquid crystal display element capable of multi-level display of high display quality using general-purpose drivers, a method of driving the element, and electronic paper having the element. To display gray level “4”, a pulse voltage of ±32 V is applied at a first step to put a cholesteric liquid crystal in a planar state (level “7”)). Then, a pulse voltage of ±24 V is applied for 2.0 ms at a sub-step to the cholesteric liquid crystal to change the gray level to level “5” that is two steps lower. A pulse voltage of ±24 V is applied for 1.0 ms at another sub-step to cause a further transition of the cholesteric liquid crystal toward a focal conic state, thereby obtaining gray level “4” that is one step lower than level “5”.
    Type: Application
    Filed: February 20, 2009
    Publication date: June 18, 2009
    Applicant: FUJITSU LIMITED
    Inventor: Masaki NOSE
  • Publication number: 20090153756
    Abstract: A liquid crystal display is disclosed, including first and second opposing substrates separated by a cell gap. The cell gap has an inner liquid crystal region including a liquid crystal composition, an outer sealant region including a sealant that bonds the first and second opposing substrates together, and a void region between the inner liquid crystal region and the outer sealant region. The sealant may be a pressure sensitive adhesive. Also disclosed is a method of manufacturing the liquid crystal display. A liquid crystal display assembly including at least two light reflecting liquid crystal displays is also disclosed, wherein at least one of the displays comprises the liquid crystal display disclosed herein.
    Type: Application
    Filed: December 13, 2007
    Publication date: June 18, 2009
    Inventors: Ralph R. Roberts, Amy J. Hite, Jane K. Wardhana, Audrey A. Sherman
  • Publication number: 20090135320
    Abstract: A display device including: a pair of substrates 10 and 12 placed so as to oppose each other; a plurality of pixel electrodes 16 formed on one 12 of the pair of substrates; a counter electrode 18 formed on the other 10 of the pair of substrates; and a modulation layer 1 provided between the plurality of pixel electrodes 16 and the counter electrode 18, the modulation layer 1 being capable of switching states between a transmitting state in which light is transmitted and a scattering state in which light is scattered. The display device further includes: a plurality of switching elements 13 formed on the one substrate 12 and electrically connected respectively to corresponding pixel electrodes 16; a plurality of wiring lines 14 disposed on the one substrate 12 and at intervals 22 from the plurality of pixel electrodes 16; and a diffraction preventing layer 30 disposed in the intervals 22 between the wiring lines 14 and the pixel electrodes 16.
    Type: Application
    Filed: March 14, 2007
    Publication date: May 28, 2009
    Inventors: Kiyoshi Minoura, Sayuri Fujiwara
  • Publication number: 20090033814
    Abstract: According to one embodiment, a method for reducing speckle in an image produced from a coherent light source includes directing a beam of coherent light at an electrically controlled diffuser. An electrical signal is applied to the electrically controlled diffuser to produce an electrical field across the electrically controlled diffuser layer. At least one of an amplitude and a frequency of the electrical signal are varied to transition the controlled diffuser between a first state and a second state. The varied application of the electrical signal operates to reduce spatial coherence in an image projected through the electrically controlled diffuser.
    Type: Application
    Filed: August 1, 2007
    Publication date: February 5, 2009
    Inventor: Sajjad Ali Khan
  • Patent number: 7382430
    Abstract: On substrates 2a, 2b of a chiral nematic liquid crystal optical element 1, transparent electrodes 3a, 3b and electrical insulation layers 4a, 4b are formed, and further resin layers 5a, 5b having a pencil hardness of “B” or less are formed on the electrical insulation layers by a spin coating method so as to be in contact with a liquid crystal layer 7. When the surface hardness of the resin layers is to be measured, a glass substrate on which a resin layer is formed by screen-printing is prepared as a test piece, and the test piece is fitted to a pencil-scratching tester. The surface hardness is measured by scratching the test piece with two kinds of testing pencil selected from testing pencils having 17 grades of density.
    Type: Grant
    Filed: March 2, 2007
    Date of Patent: June 3, 2008
    Assignee: Asahi Glass Company, Limited
    Inventors: Satoshi Niiyama, Noriko Suehiro
  • Publication number: 20080122998
    Abstract: Cholesteric liquid crystal display devices and driving methods thereof are provided. A cholesteric liquid crystal display includes a first substrate, a second substrate and a cholesteric liquid crystal layer interposed therebetween, wherein the cholesteric liquid crystal includes at least a first displaying state and a second displaying state. A capacitance detector measures the displaying state of the cholesteric liquid crystal layer and stores the measured display state as a first output signal or second output signal in a memory device.
    Type: Application
    Filed: November 19, 2007
    Publication date: May 29, 2008
    Applicant: INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE
    Inventors: Da-Wei Lee, Yi-An Sha, Jyh-Wen Shiu
  • Patent number: 7253861
    Abstract: On substrates 2a, 2b of a chiral nematic liquid crystal optical element 1, transparent electrodes 3a, 3b and electrical insulation layers 4a, 4b are formed, and further, resin layers 5a, 5b hating a pencil hardness of “B” or less are formed on the electrical insulation layers by a spin coating method so as to be in contact with a liquid crystal layer 7. When the surface hardness of the resin layers is to be measured, a glass substrate on which a resin layer is formed by screen-printing is prepared as a test piece, and the test piece is fitted to a pencil-scratching tester. The surface hardness is measured by scratching the test piece with two kinds of testing pencil selected from testing pencils having 17 grades of density.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: August 7, 2007
    Assignee: Asahi Glass Company
    Inventors: Satoshi Niiyama, Noriko Suehiro
  • Patent number: 6950086
    Abstract: A driving method for a liquid crystal display device with a cholesteric liquid crystal having a memory mode of operation including a first stage of applying a first voltage to change the state of the cholesteric liquid crystal to a homeotropic state, a second stage of applying a second voltage to change the state of the cholesteric liquid crystal to a homogeneous state or a homogeneous/planar-mixed state, and a third stage of applying a third voltage to change the state of the cholesteric liquid crystal from the homogeneous state or the homogeneous/planar-mixed state to a focalconic state.
    Type: Grant
    Filed: April 2, 2001
    Date of Patent: September 27, 2005
    Assignee: OPTREX Corporation
    Inventors: Makoto Nagai, Shinya Tahara, Tomohiro Takano, Noriko Suehiro, Satoshi Niiyama
  • Patent number: 6950171
    Abstract: This invention involves one kind of liquid crystal color light switch, made especially from cholesteric liquid crystals. By changing the voltage applied, the reflection wavelength of the color light switch can be controlled, leading to a rapid change of the reflected light from red to green to blue in rapid succession, thus creating a color display. The core technology of this invention is making the voltage applied to the cholesteric liquid crystal less than the untwisted voltage and still in good focal conic state, that is the symmetric axis are in the same direction, and the pitch is varied according to the voltage applied.
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: September 27, 2005
    Assignee: Inshon INC
    Inventor: Jing Wu Wen
  • Patent number: 6894733
    Abstract: A liquid crystal display apparatus which has: a liquid crystal display which has chiral nematic liquid crystal between a pair of substrates with electrodes thereon and which makes a display by use of selective reflection of the liquid crystal; and a driving circuit for driving the liquid crystal by applying voltages to the electrodes. When an electric field of a specified strength is applied to the chiral nematic liquid crystal, the liquid crystal changes the direction of the helical axis without untwisting. By using this characteristic, the direction of the helical axis of the liquid crystal is changed by changing the direction of the electric field applied thereto, and thereby, the liquid crystal is set to a planar state or a focal-conic state. In this way, writing on the liquid crystal is carried out.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: May 17, 2005
    Assignee: Minolta Co., Ltd.
    Inventors: Tomoo Izumi, Mitsuyoshi Miyai
  • Patent number: 6888583
    Abstract: Methods and apparatus for adjusting or reducing intrinsic DC offset potential in a Liquid Crystal Display (LCD) are taught. The methods allow the upper and lower assemblies of the LCD device to be manufactured with selected materials while achieving adjusted or reduced intrinsic DC offset potential in the finished LCD device. The methods are especially useful for reflective LCD designs where it is not possible to build the LCD with symmetric assemblies.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: May 3, 2005
    Assignee: Brillian Corporation
    Inventors: Kevin J. Ilcisin, Douglas J. McKnight
  • Patent number: 6885357
    Abstract: A method for writing pixels in a cholesteric liquid crystal display having opposing rows and columns of electrodes and cholesteric liquid crystal material disposed between the rows and columns of electrodes to define an array of pixels, the cholesteric liquid crystals having a plurality of reflective states stable in the absence of an electrical field, one state having a minimum reflection, and another state with maximum reflection includes the steps of: applying voltages to the row an column electrodes to establish a pre-selection pixel voltage having a magnitude and duration effective to change at least one possible reflective state, but ineffective to drive the liquid crystal material to a common state; applying voltages to the row and column electrodes to establish a selection pixel voltage for selecting a final reflective state for the pixel; and applying voltages to the row and column electrodes to establish a post selection pixel voltage for achieving a final desired reflective state.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: April 26, 2005
    Assignee: Eastman Kodak Company
    Inventor: Xiang-Dong Mi
  • 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: 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: 6674494
    Abstract: On substrates 2a, 2b of a chiral nematic liquid crystal optical element 1, transparent electrodes 3a, 3b and electrical insulation layers 4a, 4b are formed, and further, resin layers 5a, 5b having a pencil hardness of “B” or less are formed on the electrical insulation layers by a spin coating method so as to be in contact with a liquid crystal layer 7. When the surface hardness of the resin layers is to be measured, a glass substrate on which a resin layer is formed by screen-printing is prepared as a test piece, and the test piece is fitted to a pencil-scratching tester. The surface hardness is measured by scratching the test piece with two kinds of testing pencil selected from testing pencils having 17 grades of density.
    Type: Grant
    Filed: May 3, 2001
    Date of Patent: January 6, 2004
    Assignee: OPTREX Corporation
    Inventors: Satoshi Niiyama, Noriko Suehiro
  • Patent number: 6602563
    Abstract: A liquid crystal display which carries out matrix driving of a chiral nematic liquid crystal composition, which is capable of displaying an image theron continuously after an electric field applied thereto is turned off, by applying an electric field to the liquid crystal composition through a plurality of scan electrodes and a plurality of data electrodes which face and cross each other with the liquid crystal composition in-between. The nematic liquid crystal which is the main element of the liquid crystal composition mainly contains a liquid crystalline ester compound, a liquid crystalline stilbene compound, a liquid crystalline terphenyl compound or a liquid crystalline tolane compound.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: August 5, 2003
    Assignee: Minolta Co., Ltd.
    Inventors: Nobuyuki Kobayashi, Takeshi Kitahora, Fumie Motoori, Hideaki Ueda
  • Publication number: 20030128305
    Abstract: A liquid crystal display apparatus which has: a liquid crystal display which has chiral nematic liquid crystal between a pair of substrates with electrodes thereon and which makes a display by use of selective reflection of the liquid crystal; and a driving circuit for driving the liquid crystal by applying voltages to the electrodes. When an electric field of a specified strength is applied to the chiral nematic liquid crystal, the liquid crystal changes the direction of the helical axis without untwisting. By using this characteristic, the direction of the helical axis of the liquid crystal is changed by changing the direction of the electric field applied thereto, and thereby, the liquid crystal is set to a planar state or a focal-conic state. In this way, writing on the liquid crystal is carried out.
    Type: Application
    Filed: October 31, 2002
    Publication date: July 10, 2003
    Inventors: Tomoo Izumi, Mitsuyoshi Miyai
  • Patent number: 6590411
    Abstract: A method for measuring an image sticking defect in a liquid crystal display device includes the steps of grounding a liquid crystal cell, the liquid crystal cell includes an alignment layer, applying a first alternating current voltage to the liquid crystal cell, measuring a first capacitance of the liquid crystal cell, applying an electrical stress to the liquid crystal cell, measuring a second capacitance of the liquid crystal cell, and calculating a capacitance difference between the first capacitance and the second capacitance.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: July 8, 2003
    Assignee: LG. Philips LCD Co., Ltd.
    Inventor: Man-Hoan Lee
  • Patent number: 6531997
    Abstract: Novel addressing schemes for controlling bistable electronically addressable displays include the use of addressing signals with additional signals having opposite polarity and equal integrated signal strength, and addressing schemes that minimize the number of state changes that a display element undergoes. In one embodiment, pre-pulses are employed to apply a pre-stress to an display element that is equal and opposite to the electrical stress applied in addressing the element. In another embodiment, the addressing signal is followed by a post-stressing pulse. Methods for minimizing the number of display elements that must change state to change the image displayed include the determination of a set of elements that must be deactivated and a set of elements that must be activated to change the image depicted by a display. Alternatively, only the elements forming one image are deactivated before the elements forming a different image are activated.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: March 11, 2003
    Assignee: E Ink Corporation
    Inventors: Holly G Gates, Barrett Comiskey, Peter T. Kazlas, Jonathan D. Albert, Paul S Drzaic
  • Publication number: 20020126229
    Abstract: On substrates 2a, 2b of a chiral nematic liquid crystal optical element 1, transparent electrodes 3a, 3b and electrical insulation layers 4a, 4b are formed, and further, resin layers 5a, 5b hating a pencil hardness of “B” or less are formed on the electrical insulation layers by a spin coating method so as to be in contact with a liquid crystal layer 7. When the surface hardness of the resin layers is to be measured, a glass substrate on which a resin layer is formed by screen-printing is prepared as a test piece, and the test piece is fitted to a pencil-scratching tester. The surface hardness is measured by scratching the test piece with two kinds of testing pencil selected from testing pencils having 17 grades of density.
    Type: Application
    Filed: December 28, 2001
    Publication date: September 12, 2002
    Applicant: OPTREX Corporation
    Inventors: Satoshi Niiyama, Noriko Suehiro
  • Patent number: 6377321
    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: June 10, 1999
    Date of Patent: April 23, 2002
    Assignee: Kent Displays, Inc.
    Inventors: Asad A. Khan, Xiao-Yang Huang, Haiji Yuan, Minhua Lu, Ellison C. Urban
  • Patent number: 6366330
    Abstract: A liquid crystal material for a display device includes a liquid crystal material comprising first chiral nematic liquid crystal component and a second component that exhibits no liquid crystalline phase. The second component is present in an amount not greater than 5% by weight based upon the total weight of the liquid crystal display material and is effective to avoid image sticking of the display device when in use. The liquid crystal material has positive dielectric anisotropy. The second component may have a molecular weight not exceeding 205 grams/mole.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: April 2, 2002
    Assignee: Kent Displays Incorporated
    Inventors: Asad Aziz Khan, Xiao-Yang Huang
  • Patent number: 6274208
    Abstract: A liquid crystal composition which contains a liquid crystal tolan compound, a liquid crystal ester compound, a liquid crystal phenylcyclohexane compound and at least one chiral agent. A reflective type liquid crystal display has the liquid crystal composition and a columnar structure between substrates with ITO electrodes thereon.
    Type: Grant
    Filed: August 9, 1999
    Date of Patent: August 14, 2001
    Assignee: Minolta Co., Ltd.
    Inventors: Masako Iwamatsu, Nobuyuki Kobayashi, Hideaki Ueda
  • Patent number: 6198466
    Abstract: A nonmechanical fully electronic multifunctional digital indicator useful for providing elapsed time indications or as event counters is disclosed. The event counter uses a ChLCD-type matrix array and requires unique steps to properly erase and place new information on the display without inadvertently changing the status of individual array elements.
    Type: Grant
    Filed: September 24, 1999
    Date of Patent: March 6, 2001
    Assignee: L3 Communications Electrodynamics, Inc.
    Inventors: Robert S. Morich, Victor J. Szeplaki
  • Patent number: 6172720
    Abstract: A liquid crystal material for a display device includes a first chiral nematic liquid crystal component and a second component that exhibits no liquid crystalline phase at any temperature. The second component is present in an amount effective to reduce the bulk viscosity of the liquid crystal material by at least about 26% at room temperature or is present in an amount of at least about 5% by weight based upon the total weight of the liquid crystal material. The liquid crystal material may have a positive dielectric anisotropy. The second component may have a molecular weight not exceeding 205 grams/mole. Embodiments relate to a display device comprising the present material. Another aspect includes a method of increasing the switching speed in a display that employs the present material.
    Type: Grant
    Filed: May 23, 1997
    Date of Patent: January 9, 2001
    Assignee: Kent Displays Incorporated
    Inventors: Asad Aziz Khan, Stanley Joseph Laskos, Jr., Michael E. Stefanov
  • Patent number: 6061107
    Abstract: Polymer/cholesteric liquid crystal dispersions are provided in which the liquid crystal phase separated from the polymer matrix to form droplets. The cholesteric liquid crystals were positive dielectric anisotropic. At a zero field condition, the liquid crystal in the droplets was bistable, that is, the liquid crystal can be in either the reflecting planar state or the scattering focal conic state. When the liquid crystal 101 was in the planar texture, the helical axis of the liquid crystal was more or less perpendicular to the cell surface; colored light 105 was Bragg reflected. When the liquid crystal 101 was in the focal conic texture, the helical axis was more or less parallel to the cell surface, incident light was scattering 106 in the forward direction.
    Type: Grant
    Filed: May 7, 1997
    Date of Patent: May 9, 2000
    Assignee: Kent State University
    Inventors: Deng-Ke Yang, Zhijian Lu, J. William Doane
  • Patent number: 6005651
    Abstract: In a display panel, a first substrate is opposed to a second substrate and interposing a liquid crystal/resin composite layer. If the display panel is a transmission type display, a film for absorbing light is formed on a black matrix and between pixel electrodes. If the display panel is a reflection type display, a film for absorbing light is formed between reflection electrodes. Further, a counterelectrode is made from a multi-layer film of dielectric films and a transparent electrically conductive film for preventing reflection. The film for absorbing light includes pigments which can absorb light modulated by the liquid crystal/resin composite layer. By using the display panel, a projection display system of high contrast and high brightness can be constructed.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: December 21, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Takahara, Hideki Ohmae, Hideaki Mochizuki
  • Patent number: 5933203
    Abstract: Driver apparatus and methods of driving at least a portion of a cholesteric liquid crystal ("CLC") panel to a state having a given reflectivity. One of the methods includes the steps of: (1) initially driving the portion to a nematic phase, (2) subsequently driving the portion to a cholesteric phase focal-conic state, the cholesteric phase focal-conic state providing a known reference state for subsequent driving of the portion and (3) thereafter driving the portion to the state having the given reflectivity.
    Type: Grant
    Filed: January 8, 1997
    Date of Patent: August 3, 1999
    Assignee: Advanced Display Systems, Inc.
    Inventors: Bao-Gang Wu, Jianmi Gao, Meng Zhao
  • Patent number: 5889566
    Abstract: A light modulating apparatus containing cholesteric liquid crystals capable of indefinite zero field retention of optical images, including full color and complete gray scale capability, is described. This invention is predicated on establishment of zero field multistable liquid crystal domains representing a continuous distribution of states ranging from the highly reflective planar to the light-scattering focal-conic structures. The zero field multistable domain structure stability is achieved by controlling solid surface-liquid crystal boundary interactions to provide essential equalization of the total system energy of each of the domain structures. This is the first time this equalization, and thus zero field multistability, has been achieved without the use of a polymer gel addition to create rigid polydomains in the liquid crystal mix.
    Type: Grant
    Filed: April 17, 1997
    Date of Patent: March 30, 1999
    Assignee: Advanced Display Systems, Inc.
    Inventors: Bao-Gang Wu, Jianmi Gao, Hongxi Zhou, Yao-Dong Ma
  • Patent number: 5778625
    Abstract: A recessed lighting fixture includes a back housing which is secured to a form board for receiving poured concrete such that the concrete sets around the housing to form a recessed area in a concrete structure. The form board is joined to a stiffener plate to support the housing under the force of the concrete. The form board and stiffener plate are removed from the back housing and the internal components of the lighting fixture are disposed in and secured to the interior of the back housing to form a recessed lighting fixture which is flush with the surface of the structure, for example a concrete wall. The internal components of the fixture may subsequently be removed and replaced should the need arise as only the back housing is fixed to the concrete wall.
    Type: Grant
    Filed: October 11, 1996
    Date of Patent: July 14, 1998
    Assignee: Bega/US, Inc.
    Inventors: James B. Druffel, Larry L. Routh
  • Patent number: 5625477
    Abstract: A light modulating apparatus containing cholesteric liquid crystals capable of indefinite zero field retention of optical images, including full color and complete gray scale capability, is described. This invention is predicated on establishment of zero field multistable liquid crystal domains representing a continuous distribution of states ranging from the highly reflective planar to the light-scattering focal-conic structures. The zero field multistable domain structure stability is achieved by controlling solid surface-liquid crystal boundary interactions to provide essential equalization of the total system energy of each of the domain structures. This is the first time this equalization, and thus zero field multistability, has been achieved without the use of a polymer gel addition to create rigid polydomains in the liquid crystal mix.
    Type: Grant
    Filed: April 11, 1994
    Date of Patent: April 29, 1997
    Assignee: Advanced Display Systems, Inc.
    Inventors: Bao-Gang Wu, Jianmi Gao, Hongxi Zhou, Yao-Dong Ma