Ferroelectric Liquid Crystal Elements Patents (Class 345/97)
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Publication number: 20030174114Abstract: A liquid crystal display device afflicted with no image persistence is disclosed. The liquid crystal display device according to the present invention comprises a pixel portion in which a plurality of pixel TFTs are matrix-wise disposed, a source driver and a gate driver which feed a plurality of the TFTs with picture signals, and a liquid crystal material which has substantially no threshold value, characterized in that one frame is formed of a plurality of sub-frames, and, during at least one of a plurality of the sub-frames, the display by a reset signal is performed.Type: ApplicationFiled: March 10, 2003Publication date: September 18, 2003Applicant: Semiconductor Energy Laboratory Co., Ltd.Inventor: Shunpei Yamazaki
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Patent number: 6615163Abstract: A method for developing testing configurations and a computer system operable to implement the same. The method includes the steps of identifying factors to be tested and levels for each factor; selecting a Hadamard matrix of an appropriate size such that for any integer 1, 2 . . . n, the Hadamard matrix has a size 2n and at least (2n−1) columns, and maintains orthogonality of at least strength n when columns are selected sequentially; and creating a configuration matrix from the selected Hadamard matrix. The configuration matrix is created by first creating an integer matrix from the Hadamard matrix by combining columns of the Hadamard matrix where necessary, and replacing unassigned variables in the integer matrix in a manner that improves coverages. In one embodiment, a frequency matrix and a proportionality matrix are used to improve coverage when replacing unassigned variables.Type: GrantFiled: December 13, 1999Date of Patent: September 2, 2003Assignee: Dell USA, L.P.Inventors: Hamid Rasoulian, Stephen A. Osella
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Patent number: 6614491Abstract: There is provided a liquid crystal display which is capable of preventing light from leaking out from the peripheral portion of pixels and which has a high display performance.Type: GrantFiled: March 9, 2001Date of Patent: September 2, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Rei Hasegawa, Rieko Fukushima, Tatsuo Saishu, Hajime Yamaguchi, Kohki Takatoh
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Publication number: 20030156090Abstract: A method and apparatus for displaying information by a liquid crystal display is provided. A bistable liquid crystal display is coupled to a signal input to provide a display device. A user device is provided remote from the display device for controlling the bistable liquid crystal display. The user device has a signal output coupled to a driver control. The driver control is responsive to a user input controlled by a user to display the information by the liquid crystal display. The display device is electrically interconnected with the user device by coupling the signal output to the signal input through a signal interface.Type: ApplicationFiled: June 13, 2002Publication date: August 21, 2003Inventors: Jason Drury Munn, Scott Wayne Ferguson, James Spencer Wolff
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Publication number: 20030146894Abstract: This invention concerns a process for addressing a bistable liquid crystal material screen, characterised in that it comprises at least the step consisting of applying, to the screen column electrodes, an electrical signal whose characteristics are adapted to reduce the mean quadratic voltage of the parasite pixel pulses, in order to reduce the parasitic addressing optical effects.Type: ApplicationFiled: January 27, 2003Publication date: August 7, 2003Inventors: Jacques Angele, Romain Vercelletto, Thierry Elbhar
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Publication number: 20030146895Abstract: A pixel driving device for a liquid crystal display. The pixel driving device includes a thin film transistor (TFT), a pixel capacitor, a storage capacitor, a first common line, and a second common line. The TFT includes a gate electrode coupled to a scan line and a source coupled to the data line. The pixel capacitor is coupled to the TFT drain electrode and the first common line, while the storage capacitor is coupled to the TFT drain electrode and the second common line. The first common line and the second common line possess different common voltages. When a pixel voltage is applied to the pixel, the pixel capacitor and the storage capacitor possess different capacitor voltage values by being coupled to different common lines, respectively.Type: ApplicationFiled: February 3, 2003Publication date: August 7, 2003Inventor: Chao-Chun Chung
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Patent number: 6603444Abstract: A display element has a plurality of pixels and is constructed to display image information by modulating light passing through each pixel. The display element has the following for each of the pixels: a mask having a shield portion in part; and a first fluid and an electroconductive or polar, second fluid being immiscible with each other. An amount of the light passing through the mask is regulated in such a way that a voltage applied to the second fluid of each pixel is varied to alter the shape of an interface between the first fluid and the second fluid, so as to increase or decrease light incident to the shield portion of the mask.Type: GrantFiled: June 14, 2000Date of Patent: August 5, 2003Assignee: Canon Kabushiki KaishaInventors: Eriko Kawanami, Ichiro Onuki, Shigeo Ogura
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Patent number: 6603454Abstract: A matrix-display panel such as a liquid crystal display panel is composed of row and column electrodes and liquid crystal interposed between both row and column electrodes. Pixels formed at each intersection of the electrodes are driven by imposing composite voltages consisting of scanning voltages supplied to the row electrodes and image data voltages supplied to the column electrodes. Pixels aligned along one row electrode are alternately connected to two or three neighboring row electrodes in a zigzag manner, and an interlaced scanning is performed by jumping one or two row electrodes at a time, thereby reducing a flicker frequency to an invisible level and making a line-scroll invisible. The pixels may be driven by switching a transistor connected to each pixel.Type: GrantFiled: February 23, 2000Date of Patent: August 5, 2003Assignee: Denso CorporationInventors: Koji Nakamura, Yoshihiro Tsubaki
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Publication number: 20030142057Abstract: An information display comprises a planar electrical optical element including a plurality of pixels, each of the pixels having an optical state controlled by an electrical signal; the optical element having at least two optical states of a light scattering state and a light transmissive state, each of the pixels having the optical state reversibly changed between the scattering state and the light transmissive state; information being displayed in a planar fashion by combining the optical states of pixels; and the information being capable to be held with no electrical signal applied, and visible light having a transmittance of 60% or higher when the visible light passes from one of surfaces of the electrical optical element to the other surface through a pixel in the light transmissive state.Type: ApplicationFiled: December 4, 2002Publication date: July 31, 2003Applicant: OPTREX CorporationInventors: Satoshi Niiyama, Noriko Suehiro, Shinya Tahara, Hitoshi Tsushima
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Patent number: 6600473Abstract: The invention provides a photoconductive switching element used for light switching of a functional element driven by an AC electric field or AC current which are highly functional and inexpensive and provides a device in which such a photoconductive switching element and a functional element such as a liquid display element are combined and incorporated, and an apparatus, a recording apparatus, and a recording method which are provided with the above-mentioned device. The photoconductive switching element has at least a light transmissible electrode layer, a charge generation layer, a charge transfer layer, and a charge generation layer laminated in this order on a light transmissible substrate. The photoconductive switching element is combined with a functional element to form a device of the present invention, and the device is incorporated in an apparatus or a recording apparatus to fabricate an apparatus or a recording apparatus respectively of the present invention.Type: GrantFiled: December 28, 1999Date of Patent: July 29, 2003Assignee: Fuji Xerox Co., Ltd.Inventors: Hideo Kobayashi, Takeo Kakinuma, Minoru Koshimizu, Haruo Harada, Hiroshi Arisawa
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Patent number: 6590558Abstract: An electro optic display (10) provides an electrode configuration adjacent each pixel which allows a non-uniform electrical field to be applied across the pixel (22) so that the optical output varies in the direction transverse to the pixel thickness. This allows only part of the pixel to be turned ON, or for shading within the pixel, depending on the characteristics of the electro-optic material. In a preferred embodiment the row and column electrodes (14, 17) are each made up of a group of conductive tracks (12, 18) connected into groups by impedance elements (13, 19). Voltage ramps are applied across the electrodes via input electrodes 15 and 20. A multiphase drive scheme is described for ferro-electric and similar materials in which a number of different voltage ramps are applied to a row in succession, and at each phase the appropriate ramps are applied simultaneously to the column electrodes to build up the required pixel shape over a number of phases.Type: GrantFiled: June 19, 2001Date of Patent: July 8, 2003Assignee: Hewlett-Packard CompanyInventors: Adrian Derek Geisow, John Christopher Rudin
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Publication number: 20030122764Abstract: A method of driving a cholesteric liquid crystal display (LCD) panel by applying at least first, second, and third voltages to cholesteric liquid crystal cells of the cholesteric LCD panel is provided. The method includes alternately applying the first and second voltages to apply the third voltage, which is given by the root-mean-square value of the first and second voltages, to the cholesteric liquid crystal cells.Type: ApplicationFiled: October 18, 2002Publication date: July 3, 2003Inventors: Nam-Seok Lee, Woon-Seop Choi, Yeon-Gon Mo, Ki-Suk Seong, Seok-Hong Jeong
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Patent number: 6587100Abstract: A display device driver circuit including a first switching circuit for switching connection and disconnection between an output terminal and a first source line; a second switching circuit for switching connection and disconnection between the output terminal and a second source line; and a selecting circuit for switching a voltage output from the output terminal by controlling the first and second switching circuits. The selecting circuit controls the first and second switching circuits so that the timing for opening one of the switching circuits is faster than the timing for closing the other of the switching circuits. Consequently, a time when both switches are open occurs regularly when the voltage output is switched, so that no current will pass between the switching circuits.Type: GrantFiled: March 24, 2000Date of Patent: July 1, 2003Assignee: Oki Electric Industry Co., Ltd.Inventor: Hijiri Shirasaki
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Patent number: 6577289Abstract: A liquid crystal device comprises chiral smectic liquid crystal, two substrates and electrodes for applying a voltage to the liquid crystal to form pixels, each provided with an active element connected to an associated electrode on at least one substrate. The liquid crystal alignment forms domains D1 and D2, wherein the liquid crystal is aligned to provide an average molecular axis in a monostable alignment state under no voltage application, is tilted from such state in one direction when supplied with a voltage of a first polarity at a tilting angle which varies with the magnitude of the supplied voltage, and is tilted in the other direction when supplied with a voltage of a second and opposite polarity. Maximum tilting angles &bgr;1 and &bgr;2, formed under application of the voltages of the first and second polarities, respectively, satisfy: &bgr;1>&bgr;2>0 in domain D1 and 0<&bgr;1<&bgr;2 in domain D2.Type: GrantFiled: March 24, 2000Date of Patent: June 10, 2003Assignee: Canon Kabushiki KaishaInventors: Yasufumi Asao, Masahiro Terada, Takeshi Togano
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Patent number: 6573888Abstract: In an air traffic control system for controlling aircraft a three-dimensional position is provided to monitor a position of an air traffic controller. An image is displayed on a display portion with reference to the position of the controller. The image displayed on the display portion always appears in a front image regardless of the position of the controller or may be selected to be displayed on a selected area of the display portion determined by the position of the controller.Type: GrantFiled: December 7, 2000Date of Patent: June 3, 2003Assignees: NEC Corporation, Electronic Navigation Research Institute, Independent Administrative InstitutionInventors: Keiko Hayashi, Kakuichi Shiomi
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Patent number: 6573879Abstract: A plasma-addressed liquid crystal display device capable of high-speed drive and improved viewing characteristic is composed of a liquid crystal cell structure and plasma cell structure stacked with each other. The liquid crystal cell structure is formed by sandwiching a liquid crystal having a spontaneous polarization between a first transparent substrate having therein transparent electrode stripes and an alignment film covering the electrode stripes, and a dielectric sheet having thereon an alignment film. The plasma cell structure is formed of a second transparent substrate having thereon cathode stripes and anode stripes disposed alternately with a spacing therebetween, stacked via stripe-shaped partitions disposed along the anode stripes onto the dielectric sheet so as to form plasma channels between the partitions filled with an ionizable gas sealed up therein.Type: GrantFiled: August 17, 2001Date of Patent: June 3, 2003Assignee: Canon Kabushiki KaishaInventors: Osamu Taniguchi, Akira Tsuboyama
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Patent number: 6570550Abstract: A system for producing spatially modulated monochrome or color light having gray scale includes an active matrix liquid crystal spatial light modulator having light modulating means including (i) a layer of ferroelectric liquid crystal material which is designed to switch between ON and OFF states and (ii) active matrix means including VLSI circuitry for dividing the layer of liquid crystal material into an array of individual liquid crystal pixels and for causing each of the pixels of liquid crystal material to modulate light individually by switching between the ON and OFF states in a way that depends upon the data which the VLSI circuitry is written. The system also includes illumination means having a light source for directing light from the source into the pixel-divided layer of ferroelectric liquid crystal material in a specific way.Type: GrantFiled: March 20, 1998Date of Patent: May 27, 2003Assignee: Displaytech, Inc.Inventors: Mark A. Handschy, Michael R. Meadows
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Patent number: 6567065Abstract: A ferroelectric liquid crystal display comprises: a ferroelectric liquid crystal display element which includes a ferroelectric liquid crystal that is sandwiched between a pair of substrates having a plurality of scanning electrodes and signal electrodes deposited respectively on the opposing surfaces thereof; and a light source which successively emits a plurality of different colors of light.Type: GrantFiled: September 20, 1999Date of Patent: May 20, 2003Assignee: Citizen Watch Co., Ltd.Inventors: Shinya Kondoh, Shigekazu Takahashi
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Patent number: 6563480Abstract: A LED display panel has a plurality of pixel elements arranged in a matrix along a row direction and a column direction, wherein each of the pixel elements includes a LED and an associated memory cell for storing image data for the pixel. The memory cell functions for a video RAM generally disposed separately from the LED display panel in a conventional LED display panel. A higher-speed operation and reduction of occupied area can be obtained in the LED display panel of the present invention.Type: GrantFiled: October 20, 1998Date of Patent: May 13, 2003Assignee: NEC CorporationInventor: Akira Nakamura
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Publication number: 20030085864Abstract: Disclosed are a ferroelectric liquid crystal apparatus using a swing power supply, and a driving method for the ferroelectric liquid crystal apparatus, wherein the pulse duration of a scanning electrode driving waveform is made shorter than the pulse duration of the swing power supply, and the time from the beginning of a pulse trailing edge of the scanning electrode driving waveform to the beginning of a pulse leading edge of the swing power supply is set equal to or shorter than the period during which the pulse trailing edge of the scanning electrode driving waveform rises or falls while describing a time constant curve.Type: ApplicationFiled: September 24, 2002Publication date: May 8, 2003Applicant: CITIZEN WATCH CO., LTD.Inventor: Rintarou Takahashi
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Publication number: 20030085863Abstract: A low power consumption and fast speed driving means for cholesteric liquid crystal displays (ChLCDs). The novelty of the driving means is based upon the dynamic relaxation process of ChLCD from field induced nematic phase to the stable cholesteric phases, during which both the planar state or focal conic state can be formed simultaneously and the information can also be erased and addressed simultaneously. The driving means only consists of one erasing pulse that is higher than the phase change voltage and one addressing pulse that is lower than the phase change voltage.Type: ApplicationFiled: November 3, 2001Publication date: May 8, 2003Inventor: Yao-Dong Ma
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Patent number: 6559821Abstract: A liquid crystal display comprising one or more than one shift registers is characterized in that the timing of turning off the input gate of the inverter connected to the gate of the pMOS transistor of the CMOS transistor is earlier than that of the input gate of the inverter connected to the gate of the nMOS transistor of the CMOS transistor by the difference between the two MOS transistors in the time required for getting to a threshold level after turning off the input gate.Type: GrantFiled: October 21, 1998Date of Patent: May 6, 2003Assignee: Canon Kabushiki KaishaInventors: Takeshi Ichikawa, Katsumi Kurematsu, Osamu Koyama
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Patent number: 6549188Abstract: Ferroelectric liquid-crystal display having a broad operating temperature range. A ferroelectric liquid-crystal display containing a ferroelectric liquid-crystal mixture which is addressed with voltage pulses≧0.9 ms. The display according to the invention is particularly suitable for applications in which the length of the response time is not critical. Such displays can be operated with the same voltage over a broad temperature range; adjustment of the voltage as a function of temperature is not necessary. Examples of preferred applications are displays in chip cards, electronic price and display signs (shelf labels), PDAs (personal digital assistants) and pagers.Type: GrantFiled: June 15, 2000Date of Patent: April 15, 2003Assignee: Aventis Research & Technology Deutschland GmbH & Co.KGInventors: Ayako Takeichi, Barbara Hornung, Hans-Rolf Dübal
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Patent number: 6549185Abstract: A display apparatus includes a liquid crystal display which has a pair of plates each provided with an electrode and a liquid crystal layer retained between the plates, and a driver which is connected to said liquid crystal display for applying a voltage pulse to the electrodes. The driver applies a first voltage pulse for changing the state of the liquid crystal layer, and further, after elapsing of a predetermined time, applies a second voltage pulse for setting the liquid crystal layer to a stable state.Type: GrantFiled: September 13, 1996Date of Patent: April 15, 2003Assignee: Minola Co., Ltd.Inventor: Takuji Hatano
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Patent number: 6545656Abstract: A liquid crystal display device afflicted with no image persistence is disclosed. The liquid crystal display device according to the present invention comprises a pixel portion in which a plurality of pixel TFTs are matrix-wise disposed, a source driver and a gate driver which feed a plurality of the TFTs with picture signals, and a liquid crystal material which has substantially no threshold value, characterized in that one frame is formed of a plurality of sub-frames, and, during at least one of a plurality of the sub-frames, the display by a reset signal is performed.Type: GrantFiled: May 12, 2000Date of Patent: April 8, 2003Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Shunpei Yamazaki
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Publication number: 20030063060Abstract: A method of driving an anti-ferroelectric liquid crystal display (LCD) panel is provided that provides uniform transmittance display characteristics. In the anti-ferroelectric LCD panel, signal electrode lines are arranged in parallel above anti-ferroelectric liquid crystal cells, and at least first and second scan electrode lines are arranged below the anti-ferroelectric liquid crystal cells perpendicular to the signal electrode lines. The method includes a first driving step and a second driving step, which are repeated. Each of the first and second driving steps includes a scanning step, an inversion step, and an iteration step. In the scanning step, a scan selection voltage is applied to the first scan electrode line, and simultaneously, display data signals are applied to the signal electrode lines.Type: ApplicationFiled: July 12, 2002Publication date: April 3, 2003Applicant: Samsung SDI Co., Ltd.Inventors: Jeong-guen Yoo, Sung-chon Park
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Patent number: 6535191Abstract: A liquid crystal display device of the present invention includes: a main substrate having a main electrode; a counter substrate having a counter electrode; a liquid crystal material interposed between the main substrate and the counter substrate; and a control section for controlling a response start time of the liquid crystal material by a potential difference between a main electrode voltage that is applied to the main electrode during one frame and a counter electrode voltage that changes in a substantially continuous manner during the one frame, and for changing a transmissivity of the liquid crystal display device based on a magnitude of the main electrode voltage.Type: GrantFiled: March 13, 2000Date of Patent: March 18, 2003Assignee: Sharp Kabushiki KaishaInventor: Koichi Miyachi
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Patent number: 6531997Abstract: 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: GrantFiled: April 28, 2000Date of Patent: March 11, 2003Assignee: E Ink CorporationInventors: Holly G Gates, Barrett Comiskey, Peter T. Kazlas, Jonathan D. Albert, Paul S Drzaic
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Patent number: 6522315Abstract: A display apparatus, that includes current driving type luminescent elements, has a driving system that takes the conduction types of TFTs to control the emission of the luminescent elements into consideration. In order to reduce driving voltage and improve display quality simultaneously, the arrangement is provided such that if the second TFT which performs the “on-off” function of the current for the luminescent element is of an N channel type, the potential of the common power supply line (“com”) is lowered below the potential of the opposite electrode (“op”) of the luminescent element to obtain a higher gate voltage (“Vgcur”).Type: GrantFiled: October 16, 1998Date of Patent: February 18, 2003Assignee: Seiko Epson CorporationInventors: Tokuroh Ozawa, Mutsumi Kimura
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Patent number: 6519012Abstract: A ferroelectric liquid crystal-based light valve system with contrast control and a method for controlling contrast in a ferroelectric liquid crystal-based light valve system. The light valve system includes a light input, a ferroelectric liquid crystal-based spatial light modulator, an analyzer, and a voltage controller. The ferroelectric liquid crystal-based spatial light modulator includes signal processing electronics and an array of pixels. The array of pixels is configured to receive light from the light input and includes an array of pixel electrodes, a transparent electrode, and a layer of ferroelectric liquid crystal material. Each pixel electrode is independently switchable between a first voltage level and a second voltage level by the signal processing electronics. One of these levels may be a variable input voltage level. The analyzer has orthogonal directions of maximum transmissivity and minimum transmissivity.Type: GrantFiled: October 28, 1999Date of Patent: February 11, 2003Assignee: Hewlett-Packard CompanyInventors: Rene P. Helbing, Akinobu Kuramoto, Geraint Owen
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Patent number: 6509887Abstract: An antiferroelectric liquid crystal display comprises: an antiferroelectric liquid crystal display element which includes an antiferroelectric liquid crystal that is sandwiched between a pair of substrates having a plurality of scanning electrodes and signal electrodes deposited respectively on the opposing surfaces thereof; and a light source which successively emits a plurality of different colors of light.Type: GrantFiled: February 19, 1999Date of Patent: January 21, 2003Assignee: Citizen Watch Co., Ltd.Inventors: Shinya Kondoh, Shigekazu Takahashi
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Patent number: 6507331Abstract: A display device having a first substrate with row electrodes and a second substrate with column electrodes define pixels of a light-modulating cell. An electro-optical layer is capable of assuming a plurality of states with at least two states of which are stable in the absence of an electric field. The display device further has drive means for driving the row electrodes with selection signals and for driving the column electrodes with data signals in conformity with an image to be displayed. The first and second substrates are spaced such that the light-modulating cell has a thickness at least two times the pitch P of the electro-optical material. In the operating state, the drive means sequentially provide groups of p row electrodes (p>1) with mutually orthogonal signals during a selection period.Type: GrantFiled: May 24, 2000Date of Patent: January 14, 2003Assignee: Koninklijke Philips Electronics N.V.Inventors: Lucas J. M. Schlangen, Karel E. Kuijk
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Publication number: 20020190977Abstract: A data processing apparatus has a first processing unit for processing an input data, a second processing unit responsive to the data processed by the first processing unit for executing a processing dependent on the data and producing a display data, and a display unit having a display drive unit and a display device for displaying the display data. The second processing unit is selectively inactivated and activated under control of the first processing unit to reduce power consumption in the second processing unit. The display drive unit is also selectively inactivated and activated under control of the first processing unit to reduce power consumption in the display unit.Type: ApplicationFiled: July 24, 2002Publication date: December 19, 2002Inventors: Mitsuaki Oshima, Yoshihiro Gohara, Yoshinori Kobayashi, Shozo Fujiwara, Tsuyoshi Uemura
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Publication number: 20020190976Abstract: A data processing apparatus has a first processing unit for processing an input data, a second processing unit responsive to the data processed by the first processing unit for executing a processing dependent on the data and producing a display data, and a display unit having a display drive unit and a display device for displaying the display data. The second processing unit is selectively inactivated and activated under control of the first processing unit to reduce power consumption in the second processing unit. The display drive unit is also selectively inactivated and activated under control of the first processing unit to reduce power consumption in the display unit.Type: ApplicationFiled: July 24, 2002Publication date: December 19, 2002Inventors: Mitsuaki Oshima, Yoshihiro Gohara, Yoshinori Kobayashi, Shozo Fujiwara, Tsuyoshi Uemura
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Patent number: 6496170Abstract: A liquid crystal apparatus comprises: a liquid crystal device including a liquid crystal having a spontaneous polarization and causing a state change accompanied with a polarity inversion thereof within a response time. Drive means sequentially selects scanning signal lines each in a scanning selection period and applies data signal voltages to the pixels along an associated scanning signal line, wherein the scanning selection period for a scanning signal line is shorter than the response time for the liquid crystal at a pixel on the scanning signal line thus being liable to leave a remaining portion of polarity inversion to reach a desired state change, and the data signal voltage applied to the pixel is set to include a compensation voltage for compensating for a voltage decrease caused by the remaining portion of polarity inversion.Type: GrantFiled: April 29, 1999Date of Patent: December 17, 2002Assignee: Canon Kabushiki KaishaInventors: Akio Yoshida, Katsumi Komiyama, Takashi Enomoto
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Patent number: 6489941Abstract: A liquid crystal display apparatus with a driving circuit to make full use of an inherently high response speed of TL-AFLC. In addition to a source driver and a gate driver of conventional structures, the apparatus comprises a resetting source driver and a resetting gate driver for applying, upon writing of video signals to all pixels on a given scanning line in one horizontal period, a reset voltage for resetting beforehand any voltages remaining in all pixels on a plurality of scanning lines following that given scanning line. Application of the reset voltage takes place prior to the one horizontal period in which to write the video signals to all pixels on the scanning line in question and over a plurality of horizontal periods preceding that one horizontal period.Type: GrantFiled: March 15, 2000Date of Patent: December 3, 2002Assignee: Alps Electric Co., Ltd.Inventors: Fumiaki Inage, Naoki Ito, Chen Guo Ping
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Patent number: 6489942Abstract: A liquid crystal display device includes visual display elements, a data electrode driver circuit, a power supply circuit, and a correction pulse generator circuit for generation of correction-for-compensation pulses. The data electrode driver circuit includes a voltage application circuit and a voltage selector circuit for selecting a correction voltage when more than one display element is turned on and a non-select voltage when a display element is turned off. The voltage application circuit applies the correction voltage as output from the voltage selector circuit to a data electrode with display data changing from “0” to “1” or alternatively from “1” to “0” when the display element is turned on, which permits inputting from the correction pulse generator circuit, and the voltage application circuit applies the non-select voltage as output from the voltage selector circuit when the display element is turned off.Type: GrantFiled: July 11, 2000Date of Patent: December 3, 2002Assignee: Hitachi, Ltd.Inventor: Shinsaku Chiba
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Publication number: 20020158831Abstract: An antiferroelectric liquid crystal display, which is equipped with an antiferroelectric liquid crystal panel having an antiferroelectric liquid crystal sandwiched between a pair of substrates, performs at least one scanning period when carrying out a display based on one set of display data, wherein the scanning period comprises a selection period for determining the state of the antiferroelectric liquid crystal, a non-selection period for holding the state determined in the selection period, and a reset period for resetting pixels to a black display state before initiating the selection period. The length of the reset period is adjusted according to the speed of change in the display data. Alternatively, the pixels are reset to a white display state in the reset period and, during that period, the backlight is turned off.Type: ApplicationFiled: April 25, 2001Publication date: October 31, 2002Applicant: CITIZEN WATCH CO., LTD.Inventor: Shinya Kondoh
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Publication number: 20020149555Abstract: In a pixel circuit constituting one pixel of the two-dimensional matrix light modulation device consisting of a plurality of pixels, a drive circuit (DR) for driving a light modulating layer (PM) is constituted by a ferroelectric gate PET (Tr). The pixel electrode (1) in each pixel circuit is connected to the drain of the ferroelectric gate PET (Tr), and voltage (Vcom) is applied to a counter electrode (2). The source electrodes and substrate electrodes of the matrix light modulation device of the same column are connected together, and a data signal (Vb) is input in a column unit. Likewise, the gate electrodes of the same row are connected together, and a row selecting signal (Vg) is input in a row unit.Type: ApplicationFiled: September 29, 1998Publication date: October 17, 2002Inventor: KOICHI KIMURA
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Patent number: 6456266Abstract: The motion picture quality of liquid crystal display apparatus is improved by placing a non-display period depending on the responsiveness of the liquid crystal and a backlight source. For this purpose, a sub-period is set, within one frame period, for displaying a luminance corresponding to prescribed picture data so as to provide a time integral of luminance corresponding to a maximum luminance not exceeding a certain threshold, and another sub-period for displaying a lower luminance is placed in the same one frame period.Type: GrantFiled: June 30, 1999Date of Patent: September 24, 2002Assignee: Canon Kabushiki KaishaInventors: Jun Iba, Katsumi Komiyama, Shigeyuki Matsumoto
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Patent number: 6452581Abstract: A liquid crystal device of the type comprising a pair of substrates and a chiral smectic liquid crystal disposed between the substrates so as to form at least one pixel, is driven by a driving method including applying a signal waveform to a selected pixel. The driving method includes the step of applying the signal waveform which includes a clear pulse for placing the liquid crystal in a first state and a writing pulse subsequent to the clear pulse for selectively placing the liquid crystal in a second state depending on input data. The writing pulse includes a higher voltage portion and a pair of lower voltage portions sandwiching the higher voltage portion. The writing pulse is effective in reducing power consumption while ensuring a wider drive margin.Type: GrantFiled: April 10, 1998Date of Patent: September 17, 2002Assignee: Canon Kabushiki KaishaInventors: Kazunori Katakura, Shinjiro Okada, Akira Tsuboyama, Jun Iba
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Patent number: 6448952Abstract: A device for displaying a stereoscopic image in which cross-talk is suppressed. A left eye image and a right eye image alternately displayed on a liquid crystal display panel are viewed through an eye shutter having a left eye and a right eye shutter which are alternately switched. The image is displayed on the panel by sequentially supplying scanning voltages on a scanning electrode array and supplying image data voltages on a data electrode array in synchronism with the scanning voltages. The display panel is divided into an upper part and a lower part which are scanned separately in opposite directions. The left eye image is displayed in the first field during which all scanning electrodes in both parts are scanned, and the right eye image is similarly displayed in the second field following the first field. A certain time interval is provided between the first and second fields, while properly setting the eye shutter switching timing.Type: GrantFiled: January 24, 2000Date of Patent: September 10, 2002Assignee: Denso CorporationInventors: Akito Toyoda, Kenji Yamamoto, Masaaki Ozaki, Naoki Matsumoto
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Publication number: 20020109661Abstract: A method of addressing a bistable liquid crystal material having incremental reflectance properties disposed between opposed substrates is disclosed. One substrate has a first plurality of electrodes deposited thereon facing a second substrate which has a second plurality of electrodes disposed thereon. The intersection of the first and second plurality of electrodes forms a plurality of pixels. The addressing method includes applying a predetermined number of pulses to the first plurality of electrodes, and applying a like number of the predetermined number of pulses to the second plurality of electrodes. Each of the predetermined number of pulses has a different frequency, wherein the predetermined number of pulses are applied in a set time period.Type: ApplicationFiled: February 9, 2001Publication date: August 15, 2002Applicant: Kent Displays IncorporatedInventors: Chris Blackson, Todd Ernst, Xiao-Yang Huang
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Patent number: 6424329Abstract: A system for driving a nematic liquid crystal is used to display high definition color images at a high speed in a liquid crystal display device in which the nematic liquid crystal is confined between a common electrode and a segment electrode that are placed between two polarizing plates. The common electrode is supplied with a sequence of selection pulses, and the segment electrode is supplied with a voltage corresponding to image data to be displayed in response to the selection pulses. the segment electrode is further supplied with a voltage different from the voltage corresponding to the image data in intervals where the selection pulses are not applied to the common electrode.Type: GrantFiled: September 12, 2000Date of Patent: July 23, 2002Assignees: Fad Inc.Inventor: Masaya Okita
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Patent number: 6421037Abstract: A Silicon-Chip-Display (SCD) cell structure operable in a field sequential mode for use in liquid crystal display (LCD) devices and a method for operating the same provided. The SCD cell structure is formed of first through third write-enable transistors, first through third storage capacitors, and first through third display-enable transistors. In one preferred embodiment, each of the write-enable transistors is sequentially turned on so to pre-load video data into the corresponding storage capacitors during one color-field time prior to when each of the corresponding display-enable transistors is sequentially turned on for displaying an associated color-field. As a consequence, there is rendered a higher quality video image by allowing the LC response time and/or the light strobing time to be increased.Type: GrantFiled: April 5, 1999Date of Patent: July 16, 2002Assignee: MicroPixel, Inc.Inventor: Chih-Liang Chen
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Patent number: 6417826Abstract: A method of addressing a liquid crystal device having a plurality of scanning electrodes and a plurality of data electrodes defining a plurality of pixels at the intersections between at least one of the plurality of scanning electrodes and at least one of the plurality of data electrodes, the method comprising applying one frame of a scanning signal to one of the plurality of scanning electrodes, applying a data signal to at least one of the plurality of data electrodes, one frame of the scanning signal comprising n strobe portions, where n is an integer greater than 1, for co-operation with the at least one data signal to address one of the plurality of pixels, and at least one blanking portion, the number of blanking portions not exceeding (n−1).Type: GrantFiled: February 5, 1999Date of Patent: July 9, 2002Assignees: Sharp Kabushiki Kaisha, The Secretary of State for Defence in Her Brittanic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventors: Paul Bonnett, Michael John Towler, Diana Cynthia Ulrich
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Patent number: 6417828Abstract: An active matrix-type liquid crystal device is constituted by a pair of substrates, a chiral smectic liquid crystal composition disposed between the pair of substrates so as to form a plurality of pixels, and a plurality of active elements provided to the pixels, respectively, for driving the liquid crystal device in a matrix driving scheme. The chiral smectic liquid crystal composition may preferably comprise at least two specific fluorine-containing mesomorphic compounds and assume two stable states between which a threshold voltage for switching from one of the two stable states to the other stable state is different from a threshold voltage for switching from the other stable state to said one of the two stable states and liquid crystal molecules of the liquid crystal composition change their alignment states so as to provide a halftone state depending on a voltage applied to the chiral smectic liquid crystal.Type: GrantFiled: February 17, 2000Date of Patent: July 9, 2002Assignee: Canon Kabushiki KaishaInventors: Koichi Sato, Mineto Yagyu, Yukio Hanyu, Masahiro Terada, Koji Noguchi, Kouki Nukanobu
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Patent number: 6414667Abstract: A liquid crystal device is addressed in a multiplexed manner by a scanning signal applied in turn to a first set of electrodes together with data signals applied to a second set of electrodes. The first and second sets of electrodes define a plurality of pixels. The pattern to be exhibited by the device determines the waveform applied to the second set of electrodes which can vary between extremes of frequency. This has adverse effects on device performance, particularly with regard to contrast. To ameliorate the problem a low frequency signal is added to the scanning signal which incorporates a known strobe pulse. This low frequency signal reduces the effect on the pixels of the extremes of data signal frequency.Type: GrantFiled: January 18, 1999Date of Patent: July 2, 2002Assignees: Sharp Kabushiki Kaisha, The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventors: Paul Bonnett, Michael John Towler
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Publication number: 20020063673Abstract: An electrophoretic device is composed of a pair of electrodes that are arranged opposite to each other with a prescribed space therebetween, which contains an electrophoretic dispersion liquid containing electrophoretic particles which are dispersed in a liquid phase dispersion medium. At least one ferroelectric substance layer is arranged at a prescribed position within the space between the electrodes, and at least one of the electrodes is made of a transparent material. Applying a drive voltage between the electrodes, the electrophoretic particles are deposited on one electrode while ions of reverse polarity move towards another electrode, thus establishing the polarized state of the electrophoretic dispersion liquid, which is maintained for a long time due to the residual polarization characteristics of the ferroelectric substance layer.Type: ApplicationFiled: October 3, 2001Publication date: May 30, 2002Inventor: Hideyuki Kawai
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Patent number: 6388649Abstract: The disclosed spatial light modulator includes a pair of facing transparent electrodes, and a light-modulating layer and a photoconductive layer provided between the transparent electrodes In the spatial light modulator, the light-modulating layer has different optical states depending on an applied charge amount. Specifically, the light-modulating layer has: a first optical state when the applied charge amount is a first threshold charge amount or more; a second optical state when the applied charge amount is a second threshold charge amount or less; and a spatially uniform intermediate state between the first optical state and the second optical state depending on the applied charge amount. Also, a driving method for such a spatial light modulator is disclosed.Type: GrantFiled: March 24, 1994Date of Patent: May 14, 2002Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Yukio Tanaka, Akio Takimoto, Koji Akiyama, Yasunori Kuratomi, Junko Asayama, Hisahito Ogawa