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: 20190129256
    Abstract: Devices and methods relating to a vertical alignment layer with a preferred azimuthal angle for a liquid crystal device are provided. A method of preparation comprises preparing an alignment layer mixture of a polymeric vertical alignment material, an azo compound photo-aligned material, a reactive mesogen or liquid crystal monomer, a polyamic acid, a photo- or thermal-initiator, and an organic solvent, coating the alignment layer mixture onto a substrate, and irradiating the coated substrate with UV or blue light at an oblique angle.
    Type: Application
    Filed: June 21, 2018
    Publication date: May 2, 2019
    Inventors: CHENXIANG ZHAO, MAN CHUN TSENG, CUILING MENG, SHU TUEN TANG, HOI SING KWOK
  • Patent number: 10142602
    Abstract: A fabrication method of a polarization grating is provided. The method includes providing a polarization-sensitive material; and causing two orthogonally polarized lights to scan the polarization-sensitive material and to meet on the polarization-sensitive material.
    Type: Grant
    Filed: May 31, 2017
    Date of Patent: November 27, 2018
    Assignees: The Hong Kong University of Science and Technology, Himax Display, Inc.
    Inventors: Hoi-Sing Kwok, Li Tan, Yuet-Wing Li
  • Publication number: 20180315860
    Abstract: Aspects describe a vertical metal-oxide thin-film transistor with multiple-junction channel and a method to fabricate the same. In one example, the vertical transistor comprises a substrate, an interconnecting electrode and source and drain electrodes separated by a spacer. The vertical transistor also includes a metal oxide active layer formed over the interconnecting electrode and the source and drain electrodes and adjacent to the interconnecting electrode, the spacer, and the source and drain electrodes. Further, the vertical transistor includes a gate stack adjacent to the metal oxide active layer and a multiple-junction channel region provided within the metal oxide active layer adjacent to the gate stack.
    Type: Application
    Filed: April 28, 2017
    Publication date: November 1, 2018
    Inventors: Lei Lu, Zhi He Xia, Jia Peng Li, Man Wong, Hoi Sing Kwok
  • Publication number: 20180259813
    Abstract: Devices and method of fabrication a liquid crystal electro-optic device which is based on light scattering and diffraction from a multiple domain field-effect liquid crystal configuration are provided. The multiple domains include random liquid crystal alignment directions fabricated by photo-alignment and have sizes ranging from sub-micrometer to several micrometers. The random alignment in the plane can be of two or more directions whereas the pretilt angle can vary between zero and 90°. The randomness of the planar directions of the liquid crystal director can be generated by a designed photo mask in combination with uniaxial photo-alignment.
    Type: Application
    Filed: March 1, 2018
    Publication date: September 13, 2018
    Inventors: HOI SING KWOK, MARTIN SCHADT, FAN FAN
  • Publication number: 20180248118
    Abstract: A method of fabricating a hybrid organic-inorganic halide perovskite film includes depositing a precursor layer onto a substrate, the precursor layer comprising metal halide, placing an organic source-material layer onto a boat, the organic source-material layer comprising an organic cation, and annealing the precursor layer and the organic source-material layer in a vacuum chamber enclosed in a constrained volume.
    Type: Application
    Filed: August 17, 2016
    Publication date: August 30, 2018
    Applicant: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Hoi Sing KWOK, Guijun LI, Yeuk Lung Jacob HO, Man WONG
  • Publication number: 20180240821
    Abstract: This disclosure relates generally to the three-dimensional (3D) integrated thin-film transistors (TFTs) with silicon and metal-oxide (MO) semiconductors as the active layers. In one or more embodiments, an apparatus is provided that comprises a first transistor comprising a silicon active layer, and a second transistor comprising a metal oxide active layer. The second transistor is vertically stacked on the first transistor, and the first transistor and the second transistor share a gate electrode formed between the silicon active layer and the metal oxide active layer. With these embodiments, the gate electrode corresponds to a top gate of the first transistor and a bottom gate of the second transistor.
    Type: Application
    Filed: February 20, 2018
    Publication date: August 23, 2018
    Inventors: Lei Lu, Wei Zhou, Man Wong, Hoi Sing Kwok
  • Publication number: 20180216004
    Abstract: A low birefringence ferroelectric liquid crystal (FLC) mixture composed of at least two components shows birefringence in the range 0.05 to 0.14, which is suitable for the modern display and photonic devices. The cell gap can be tuned from 1.5 ?m to 4 ?m to reduces the fabrication complexity and chromatic distortion by electro-optical modulation. The FLC mixtures can be employed in a wide temperature range. The characteristics of the said FLC mixture can be tuned by tuning the concentration of the constituents of the mixture. The helical pitch of the FLC mixtures can be varied from 100 nm to 10 ?m. A smectic tilt angle can be varied between 17° to 45° and the spontaneous polarization can be tuned over a wide range to meet requirements of different electro-optical modes, and the FLC mixture is applicable for a wide variety of electro-optical effects.
    Type: Application
    Filed: January 30, 2018
    Publication date: August 2, 2018
    Inventors: VALERII VLADIMIROVICH VASHCHENKO, EVGENII PAVLOVICH POZHIDAEV, ABHISHEK KUMAR SRIVASTAVA, VLADIMIR GRIGORIEVICH CHIGRINOV, HOI SING KWOK
  • Patent number: 10032924
    Abstract: An apparatus is provided that includes a substrate and source and drain regions within an annealed active layer having resulted from an annealing of an active layer comprising metal-oxide and formed on the substrate, and an impermeable layer over the source and drain regions of the annealed active layer, wherein the annealing resulting in the annealed active layer was performed with the impermeable layer over portions of the active layer corresponding to the source and drain regions, thereby resulting in a reduction of a resistivity of the source and drain regions of the annealed active layer relative to the active layer. In another aspect, a junctionless transistor is provided wherein the entire active area has a low resistivity based on annealing of an active layer including metal oxide while uncovered or at least partially covered with layers of various gas permeability under oxidizing or non-oxidizing conditions.
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: July 24, 2018
    Assignee: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Lei Lu, Man Wong, Hoi Sing Kwok
  • Patent number: 9960281
    Abstract: Thin film transistors are provided that include a metal oxide active layer with source and drain regions having a reduced resistivity relative to the metal oxide based on doping of the source and drain regions at room temperature. In an aspect, a transistor structure is provided, that includes a substrate, and source and drain regions within a doped active layer having resulted from doping of an active layer comprising metal-oxide and formed on the substrate, wherein the doped active layer was doped at room temperature and without thermal annealing, thereby resulting in a reduction of a resistivity of the source and drain regions of the doped active layer relative to the active layer prior to the doping. In an aspect, the source and drain regions have a resistivity of about 10.0 m?·cm after being doped with stable ions and without subsequent activation of the ions via annealing.
    Type: Grant
    Filed: February 9, 2015
    Date of Patent: May 1, 2018
    Assignee: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Lei Lu, Man Wong, Hoi Sing Kwok
  • Patent number: 9946133
    Abstract: An electrically suppressed helix (ESH) ferroelectric liquid crystal (FLC) display cell with fast response includes: a liquid crystal layer, disposed between two transparent substrates, wherein helix pitch of chiral smectic liquid crystals of the liquid crystal layer is less than the thickness of the liquid crystal layer; at least one polarizer; and a voltage source, configured to apply electrical driving voltage pulses to electrodes of the display cell with amplitude greater than a critical voltage for helix unwinding of the chiral smectic liquid crystals.
    Type: Grant
    Filed: March 10, 2016
    Date of Patent: April 17, 2018
    Assignee: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Abhishek Kumar Srivastava, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Patent number: 9933685
    Abstract: A liquid crystal Fresnel lens is provided. The liquid crystal Fresnel lens includes a liquid crystal cell and two polarizers. The liquid crystal cell includes: two transparent substrates having conducting layers disposed thereon with alignment layers, wherein an alignment pattern formed by the alignment layers are configured to provide multiple alignment domains in a Fresnel zones pattern, and wherein an easy axis of adjacent alignment domains are oriented at an angle relative to one another; and a ferroelectric liquid crystal layer disposed between the two transparent substrates, wherein the ferroelectric liquid crystal layer has a planar surface orientation and smectic layers perpendicular to the two transparent substrates. The liquid crystal cell is disposed between the two polarizers.
    Type: Grant
    Filed: August 5, 2014
    Date of Patent: April 3, 2018
    Assignee: The Hong Kong University of Science and Technology
    Inventors: Abhishek Kumar Srivastava, Xiaoqian Wang, Vladimir Grigorievich Chigrinov, Hoi-Sing Kwok
  • Publication number: 20180039141
    Abstract: A composite photoalignment layer for aligning liquid crystal molecules includes: a monomeric material; a photoinitiator or a thermal initiator; and an azo dye material. A method for preparing a composite photoalignment layer for aligning liquid crystal molecules includes: mixing, in solution form, a monomeric material, a photoinitiator or a thermal initiator, and an azo dye material; coating the mixed solution onto a substrate to form a thin film; exposing the thin film to polarized light; and, with a thermal initiator, heating the thin film to polymerize the monomeric material and form a solid thin film.
    Type: Application
    Filed: October 17, 2017
    Publication date: February 8, 2018
    Inventors: Man Chun TSENG, Abhishek Kumar SRIVASTAVA, Cuiling MENG, Vladimir Grigorievich CHIGRINOV, Hoi Sing KWOK, Yue SHI, Yeuk Lung Jacob HO, Chenxiang ZHAO
  • Publication number: 20180017833
    Abstract: A standing helix ferroelectric liquid crystal display cell includes: two transparent substrates (102A, 102B); a ferroelectric liquid crystal layer (104) comprising ferroelectric liquid crystals in a standing helix configuration, the ferroelectric liquid crystal layer (104) being disposed between the two transparent substrates (102A, 102B), the ferroelectric liquid crystals having a helix axis perpendicular to the two substrates (102A, 102B) and chiral smectic liquid crystal helix pitch shorter than a wavelength of a polarized light normally impinging at least one of the two transparent substrates (102A, 102B); and inter-digital electrodes (105), disposed in plane with the two transparent substrates (102A, 102B), configured to apply an electric field to the ferroelectric liquid crystal layer (104) that provides a driving voltage below a critical voltage for helix unwinding.
    Type: Application
    Filed: January 20, 2016
    Publication date: January 18, 2018
    Inventors: Evgenii P. POZHIDAEV, Alexei D. KISELEV, Abhishek K. SRIVASTAVA, Vladimir G. CHIGRINOV, Hoi Sing KWOK
  • Publication number: 20170365228
    Abstract: Systems and methods for driving a pixel of a liquid crystal pixel array with a driving circuit are provided. An exemplary method includes: providing a data signal (Dm) to a storage element via the first transistor (T1); and providing a ramping voltage signal (VRAMP) to a gate of a second transistor (T2) of the driving circuit to control the on-off status of the second transistor (T2); wherein the ramping voltage signal (VRAMP) is based on data stored at the storage element; and wherein a duration of an on-state of the second transistor (T2) corresponds to a transmitting state for the pixel.
    Type: Application
    Filed: November 6, 2015
    Publication date: December 21, 2017
    Inventors: Hoi Sing KWOK, Tsz Kin HO, Vladimir G. CHIGRINOV
  • Patent number: 9818607
    Abstract: Techniques are provided for forming thin film transistors having a polycrystalline silicon active layer formed by metal-induced crystallization (MIC) of amorphous silicon in an oxidizing atmosphere. In an aspect, a transistor device, is provided that includes a source region and a drain region formed on a substrate, and an active channel region formed on the substrate and electrically connecting the source region and the drain region. The active channel region is formed with a polycrystalline silicon layer having resulted from annealing an amorphous silicon layer formed on the substrate and having a metal layer formed thereon, wherein the annealing of the amorphous silicon layer was at least partially performed in an oxidizing ambience, thereby resulting in crystallization of the amorphous silicon layer to form the polycrystalline silicon layer.
    Type: Grant
    Filed: June 22, 2015
    Date of Patent: November 14, 2017
    Assignee: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Hoi Sing Kwok, Man Wong, Rongsheng Chen, Meng Zhang, Wei Zhou
  • Patent number: 9791743
    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: Grant
    Filed: June 25, 2014
    Date of Patent: October 17, 2017
    Assignee: Nano and Advanced Materials Institute Limited
    Inventors: Qi Guo, Abhishek Kumar Srivastava, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Publication number: 20170264869
    Abstract: A fabrication method of a polarization grating is provided. The method includes providing a polarization-sensitive material; and causing two orthogonally polarized lights to scan the polarization-sensitive material and to meet on the polarization-sensitive material.
    Type: Application
    Filed: May 31, 2017
    Publication date: September 14, 2017
    Applicants: The Hong Kong University of Science and Technology, Himax Display, Inc.
    Inventors: Hoi-Sing Kwok, Li Tan, Yuet-Wing Li
  • Patent number: 9743054
    Abstract: A projection device including a light source, a reflective spatial polarization modulator, a polarization grating, and a projection lens is provided. The light source is configured to provide a light beam. The reflective spatial polarization modulator is disposed on a path of the light beam and configured to reflect the light beam and modulate a polarization state of the light beam. The polarization grating is disposed on the path of the light beam between the light source and the reflective spatial polarization modulator, wherein the reflective spatial polarization modulator reflects the light beam from the reflective spatial polarization modulator back to the polarization grating. The projection lens is disposed on the path of the light beam from the reflective spatial polarization modulator, wherein the polarization grating is disposed on the path of the light beam between the reflective spatial polarization modulator and the projection lens.
    Type: Grant
    Filed: March 12, 2014
    Date of Patent: August 22, 2017
    Assignees: The Hong Kong University of Science and Technology, Himax Display, Inc.
    Inventors: Hoi-Sing Kwok, Li Tan, Yuet-Wing Li
  • Patent number: 9739448
    Abstract: A liquid crystal display (LCD) backlight system includes: a light source, configured to generate light; a patterned polarization grating polarization converter (PPG-PC) assembly, configured to convert the generated light from a first polarization state to a second polarization state. The PPG-PC further includes: a patterned polarization grating (PPG) having a plurality of domains, wherein the plurality of domains of the PPG include at least two different types of domains, and wherein each domain of the PPG is configured to diffract incident light into first and second types of light beams corresponding to a first diffraction order; and a patterned retarder (PR), having a plurality of domains, the plurality of domains of the PR including domains corresponding to areas where the first type of light beams output from the PPG and including domains corresponding to areas where the second type of light beams output from the PPG converge.
    Type: Grant
    Filed: April 17, 2015
    Date of Patent: August 22, 2017
    Assignee: THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
    Inventors: Tao Du, Fan Fan, Vladimir Grigorievich Chigrinov, Hoi Sing Kwok
  • Patent number: 9684206
    Abstract: Provided is a liquid crystal alignment layer of which a constituent member is a polymer represented by the general formula (I).
    Type: Grant
    Filed: June 27, 2012
    Date of Patent: June 20, 2017
    Assignee: DIC CORPORATION
    Inventors: Martin Schadt, Vladimir Grigorievich Chigrinov, Hoi-Sing Kwok, Sayaka Nose, Masayuki Iwakubo, Masanao Hayashi, Yutaka Nagashima, Isa Nishiyama, Haruyoshi Takatsu