Patents by Inventor Hoi-Sing Kwok

Hoi-Sing Kwok has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20150029453
    Abstract: A liquid-crystal photo-alignment layer that is composed of polymer stabilized azo dyes is provided, where a polymer network is introduced in the photo-alignment layer for stabilization. The photo-alignment layer is realized based on a two-step irradiation to first achieve molecule alignment to form the photo-alignment layer and then stabilize this layer. To realize the photo-alignment layer, a pre-determined surface of the substrate is first coated with a film of mixture. The mixture comprises an azo dye and a monomer preferably mixed in an optimal concentration of 0.67 wt/wt. The azo dye and the monomer have light-absorption peaks at different wavelengths such that photo-alignment of the azo-dye molecules and stabilization of the photo-alignment layer by polymerization of the monomer are achievable by two separate exposures of light to the film.
    Type: Application
    Filed: June 25, 2014
    Publication date: January 29, 2015
    Inventors: Qi GUO, Abhishek Kumar SRIVASTAVA, Vladimir Grigorievich CHIGRINOV, Hoi Sing KWOK
  • Patent number: 8878176
    Abstract: A thin-film transistor with a fluorinated channel and fluorinated source and drain regions and methods of fabrication are provided. The thin-film transistor includes: a substrate; a semiconductor active layer of fluorine-doped metal-oxide formed on the substrate; fluorine-doped source and drain regions disposed adjacent to the semiconductor active layer; a gate electrode disposed over the semiconductor active layer, configured to induce a continuous conduction channel between the source and drain regions; and a gate dielectric material separating the gate electrode and the channel.
    Type: Grant
    Filed: August 10, 2012
    Date of Patent: November 4, 2014
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Man Wong, Hoi Sing Kwok, Zhi Ye
  • Patent number: 8854580
    Abstract: A method of producing spatially varying pretilt angles across a liquid crystal cell coats a substrate with a polyimide alignment layer and a layer of photoalignment material on top of the polyimide layer. An applied beam with variable light dosage spatial or temporal profiles is then used to achieve a corresponding pretilt angle distribution.
    Type: Grant
    Filed: March 2, 2012
    Date of Patent: October 7, 2014
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Hoi Sing Kwok, Yuet Wing Li, Man Chun Tseng
  • Publication number: 20140221574
    Abstract: Provided is a liquid crystal alignment layer of which a constituent member is a polymer represented by the general formula (I).
    Type: Application
    Filed: June 27, 2012
    Publication date: August 7, 2014
    Applicant: DIC CORPORATION
    Inventors: Martin Schadt, Vladimir Grigorievich Chigrinov, Hoi-Sing Kwok, Sayaka Nose, Masayuki Iwakubo, Masanao Hayashi, Yutaka Nagashima, Isa Nishiyama, Haruyoshi Takatsu
  • Patent number: 8754416
    Abstract: The present invention provides a method of an active-matrix thin film transistor array, comprising of two levels of metallic interconnections formed from one layer of metallic conductor; and thin-film transistors with source, drain and gate electrodes either fully or partially replaced with metal, and wherein the pixel electrodes are polycrystalline silicon.
    Type: Grant
    Filed: November 24, 2006
    Date of Patent: June 17, 2014
    Assignee: The Hong Hong University of Science and Technology
    Inventors: Hoi-Sing Kwok, Man Wong, Zhiguo Meng, Dongli Zhang, Jiaxin Sun, Xiuling Zhu
  • Patent number: 8755022
    Abstract: The invention relates to liquid crystal display cells with fast response and continuous gray scale. The liquid crystal cell is based on a field-sequential color system (“FSC”) and comprises a chiral smectic liquid crystal whose helix pitch is less than thickness of liquid crystal layer placed between two polarizers, as well as a source of voltage applied to electrodes of the cell, wherein the amplitude of the applied voltage is less than the critical voltage amplitude of the helix unwinding. The liquid crystal has one steady state corresponding to twisted helix without applied voltage.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: June 17, 2014
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Vladimir Grigorievich Chigrinov, Evgeny Pavlovich Pozhidaev, Anatoli Alexandrovich Murauski, Hoi Sing Kwok
  • Publication number: 20140159039
    Abstract: A thin film transistor includes: a source region; a drain region; and a polycrystalline thin film active channel region connected to the source region and the drain region, the active channel region comprising grains and being doped with a two-dimensional pattern comprising a plurality of doped regions, the plurality of doped regions each comprising at least portions of a plurality of the grains and at least one grain boundary.
    Type: Application
    Filed: December 12, 2013
    Publication date: June 12, 2014
    Inventors: Hoi Sing KWOK, Meng ZHANG, Shuming CHEN, Wei ZHOU, Man WONG
  • Publication number: 20140118650
    Abstract: A field sequential color (FSC) ferroelectric liquid crystal (FLC) display cell, part of an FSC display, is provided. The FSC FLC display cell includes: two polarizers; an FLC layer, positioned between the two polarizers, the FLC layer comprising FLCs with helix pitch less than the thickness of the FLC layer; and a voltage source, configured to apply an electrical driving voltage to the FLC layer, the electrical driving voltage applied to the FLC layer having an amplitude greater than a threshold voltage for helix unwinding, and wherein the voltage source is further configured to apply electrical driving voltages to light emitting diodes (LEDs) of the FSC display to illuminate pixels of the FSC display. The pixels are illuminated in an FSC manner The FLC layer is configured to provide a defect-free layer of FLC under the electrical driving voltage applied to the FLC layer.
    Type: Application
    Filed: November 1, 2013
    Publication date: May 1, 2014
    Inventors: Abhishek Kumar SRIVASTAVA, Ying MA, Vladimir Grigorievich CHIGRINOV, Hoi Sing KWOK
  • Publication number: 20130314631
    Abstract: A liquid crystal (LC) pixel, a method for providing an output thereof and a liquid crystal display device are provided. The LC pixel includes: a first electrode (5) having comb-like structures; an alignment layer (6) adjacent to the first electrode (5), wherein the alignment layer (6) is patterned with local areas that are different from the remaining area of the alignment layer (6) and wherein the local areas are configured to produce local defects in initial orientation in an LC layer (1) upon application of a control voltage; and the LC layer (1), configured to asymmetrically diffract light passing through the LC layer (1) based on configuration of the comb-like structures and the alignment layer (6).
    Type: Application
    Filed: February 10, 2012
    Publication date: November 28, 2013
    Applicant: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Valentin Tsvetkov, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Publication number: 20130301126
    Abstract: A polarization converter and polarization conversion systems are provided. The polarization converter and polarization conversion systems include a patterned polarization grating with left hand and right hand polarization grating domains. The polarization grating domains are configured to diffract incident non-polarized light into beams having left and right circular polarization states.
    Type: Application
    Filed: May 6, 2013
    Publication date: November 14, 2013
    Applicant: The Hong Kong University of Science and Technology
    Inventors: Tao DU, Fan FAN, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Patent number: 8576485
    Abstract: A method of forming a polarizing material is provided including exposing a layer of dichroic material to activating light illumination to provide an ordered structure with a distinguished absorption axis and thus photo-induce polarization, and fixing the induced polarization by polymerization of the dichroic layer. Novel polarizing materials formed thereby are also provided. By selectively exposing regions of the dichroic material to differing activating radiation, different regions with different polarization axes can be created. The polarizing material can also be provided with a coating or coatings to alter the spectral responses, and a stack formed of a plurality if dichroic layers can be provided.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: November 5, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Vladimir Markovich Kozenkov, Wing Chiu Yip, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Patent number: 8508448
    Abstract: This invention provides a method and apparatus for driving bistable cholesteric liquid crystal displays. The method and apparatus provided a display in which all the pixels are initially driven to the P state. Selected pixels for the display are then driven to the FC state to provide the desired message. The state of the pixels is then maintained for a viewing period prior to any resetting of the display to the P state. The switching from the P state to the FC state allows fast addressing times and lower voltages to be used in driving the display.
    Type: Grant
    Filed: November 7, 2005
    Date of Patent: August 13, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Hoi-Sing Kwok, Fei-Hong Yu, Qing-Cheng Li, Wing-Chiu Yip
  • Patent number: 8482506
    Abstract: Methods and systems for displaying videos with high contrast using fast transient response of liquid crystal materials are disclosed. The system comprises a liquid crystal material treated with a chiral dopant, which is aligned between two substrates with conductive layer on each substrate. The system can be operated in an active or passive matrix mode display. The active matrix display can be a thin film transistor (TFT) or MOS transistor, whereas no transistors are used for the passive matrix mode display. A full color display, with high contrast, can be achieved by illuminating the transient liquid crystal material with a pulsed backlight.
    Type: Grant
    Filed: December 31, 2007
    Date of Patent: July 9, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Hoi Sing Kwok, Yuet Wing Li
  • Patent number: 8471999
    Abstract: Disclosed herein is a liquid crystal lens with a variable focal length. The gradient profile of the liquid crystals molecules that causes the gradient profile of the refractive index is achieved by inducing non-uniformly distributed anchoring energy and an external electric or magnetic field applied to the liquid crystal layer. Unlike existing electrically controlled liquid crystal lens, the external electric or magnetic field has a uniform spatial distribution within the liquid crystal layer. The focal length of the liquid crystal lens is controlled via the non-uniformly distributed anchoring energy and by varying the uniformly distributed electric or magnetic field.
    Type: Grant
    Filed: April 20, 2009
    Date of Patent: June 25, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Sergiy Valyukh, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Publication number: 20130116396
    Abstract: The present invention relates to materials used for aligning liquid crystals of liquid crystal display elements and to a polymer for use in liquid crystal vertical alignment layer used in producing a liquid crystal vertical alignment layer. The polymer for use in a liquid crystal vertical alignment layer includes (a) a moiety that is photochemically isomerizable but not photochemically crosslinked, (b) a moiety that is photochemically crosslinkable, and (c) a moiety that stabilizes a vertical alignment. The polymer can be used to produce a vertical alignment layer that has a liquid crystal alignment property enabling control of alignment at a low UV dose and that offers a large pretilt angle and superior optical stability.
    Type: Application
    Filed: March 29, 2011
    Publication date: May 9, 2013
    Applicant: DIC CORPORATION
    Inventors: Sayaka Nose, Yutaka Nagashima, Isa Nishiyama, Haruyoshi Takatsu, Martin Schadt, Vladimir Chigrinov, Hoi Sing Kwok
  • Patent number: 8426865
    Abstract: A low temperature polycrystalline silicon device and techniques to manufacture thereof with excellent performance. Employing doped poly-Si lines which we called a bridged-grain structure (BG), the intrinsic or lightly doped channel is separated into multiple regions. A single gate covering the entire active channel including the doped lines is still used to control the current flow. Using this BG poly-Si as an active layer and making sure the TFT is designed so that the current flows perpendicularly to the parallel lines of grains, grain boundary effects can be reduced.
    Type: Grant
    Filed: February 4, 2008
    Date of Patent: April 23, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Hoi Sing Kwok, Man Wong, Zhiguo Meng, Shuyun Zhao
  • Patent number: 8415473
    Abstract: A class of luminescent gold(III) compounds containing a tridentate ligand with one strong ?-donating group having the chemical structure depicted by generic formula (I): wherein: (a) X is selected from nitrogen; (b) Y and Z selected from carbon; (c) A is cyclic structure derivative of pyridine group; (d) B and C are cyclic structure derivative of phenyl groups; (e) R1 is an optionally substituted carbon donor ligand attached to the gold atom; (f) n is zero, a positive integer or a negative integer.
    Type: Grant
    Filed: June 30, 2009
    Date of Patent: April 9, 2013
    Assignee: Versitech Limited
    Inventors: Vivian Wing-Wah Yam, Vonika Ka-Man Au, Mei-Yee Chan, Keith Man-Chung Wong, Hoi-Sing Kwok
  • Publication number: 20130037798
    Abstract: A thin-film transistor with a fluorinated channel and fluorinated source and drain regions and methods of fabrication are provided. The thin-film transistor includes: a substrate; a semiconductor active layer of fluorine-doped metal-oxide formed on the substrate; fluorine-doped source and drain regions disposed adjacent to the semiconductor active layer; a gate electrode disposed over the semiconductor active layer, configured to induce a continuous conduction channel between the source and drain regions; and a gate dielectric material separating the gate electrode and the channel.
    Type: Application
    Filed: August 10, 2012
    Publication date: February 14, 2013
    Applicant: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Man WONG, Hoi Sing KWOK, Zhi YE
  • Patent number: 8358391
    Abstract: We disclose a new method of preparing liquid crystal alignment layers that can produce controllable pretilt angles from near 0 to near 90°. It is based on the stacking of two alignment materials sequentially, with the first one being continuous and the second one being discontinuous leaving part of the first layer exposed.
    Type: Grant
    Filed: May 6, 2009
    Date of Patent: January 22, 2013
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Hoi Sing Kwok, Yuet Wing Li, Chung Yung Lee
  • Patent number: 8338237
    Abstract: The invention provides a method for forming thin film transistors including a polycrystalline semiconducting film. The method comprises depositing a first layer of amorphous semiconducting thin film on to a substrate; depositing a second layer of thin film on to the first layer of amorphous semiconducting thin film; patterning the second layer of thin film so that the first layer of amorphous semiconducting thin film is exposed at selected locations; exposing the first and second layers of thin film to a nickel containing compound in either a solution or a vapor phase ; removing the second layer of thin film; and annealing the first layer of amorphous semiconducting thin film at an elevated temperature so the first layer of amorphous semiconducting thin film converts into a polycrystalline semiconducting thin film.
    Type: Grant
    Filed: July 22, 2010
    Date of Patent: December 25, 2012
    Assignee: Hong Kong University of Science and Technology
    Inventors: Hoi Sing Kwok, Man Wong, Zhiguo Meng, Shuyun Zhao, Chunya Wu