Patents by Inventor Kei-Hsiung Yang

Kei-Hsiung Yang 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: 20030234901
    Abstract: A liquid crystal display has a pair of transparent substrates disposed opposite to each other sandwiching a liquid crystal layer therebetween, and the liquid crystal layer comprises a plurality of liquid crystal molecules and chiral components. A plurality of scanning electrodes and signal electrodes are patterned on the first substrate to define a plurality of pixel areas, wherein each pixel area has a first area and a second area. A plurality of switching devices are formed on the plurality of pixel areas and connected to the scanning electrodes, the signal electrodes and the pixel electrodes. A protrusive structure with a plurality of protrusions formed in each pixel area to generate a pretilt angle for liquid crystal molecules.
    Type: Application
    Filed: August 29, 2002
    Publication date: December 25, 2003
    Applicant: HannStar Display Corp.
    Inventors: Seok Lyul Lee, Ming-Tien Lin, Kei-Hsiung Yang, Ching-Chao Chang
  • Patent number: 6665033
    Abstract: A method for preparing an alignment layer surface provides a surface on the alignment layer. The surface is bombarded with ions, and reactive gas is introduced to the ion beam to saturate dangling bonds on the surface. Another method for preparing an alignment layer surface provides a surface on the alignment layer. The surface is bombarded with ions and quenched with a reactive component to saturate dangling bonds on the surface.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: December 16, 2003
    Assignee: International Business Machines Corporation
    Inventors: Alessandro C. Callegari, Praveen Chaudhari, Fuad E. Doany, James P. Doyle, Eileen A. Galligan, James H. Glownia, Gareth G. Hougham, James A. Lacey, Shui-Chih Lien, Minhua Lu, Alan E. Rosenbluth, Kei-Hsiung Yang
  • Patent number: 6650383
    Abstract: A reflective liquid crystal lightvalve for modulating the polarization of incident light within a specified band of wavelengths into on and off states, comprises: (i) a pixelated reflective backplane; (ii) a first liquid crystal layer, positioned proximate the pixelated reflective backplane, the first liquid crystal layer being tuned in the off state to switch incident light at the center of the specified band of wavelengths into a state that is not fully off; and (iii) a second liquid crystal layer, positioned proximate the first liquid crystal layer wherein the first liquid crystal layer is positioned between the second liquid crystal layer and the pixelated reflective backplane, the second liquid crystal layer having a birefringence which, at a given depth within its thickness, is substantially equal and opposite to a birefringence of a layer within the first liquid crystal layer that is located at a matching distance from a midplane separating the first and second liquid crystal layers.
    Type: Grant
    Filed: May 25, 2000
    Date of Patent: November 18, 2003
    Assignee: International Business Machines Corporation
    Inventors: Minhua Lu, Alan Edward Rosenbluth, Kei-Hsiung Yang
  • Publication number: 20030142257
    Abstract: Multi-domain liquid crystal cells having twist angles less than 90 degrees, and LCDs containing such liquid crystal cells, are provided. Such liquid crystal cells are stable, particularly at zero and high fields, and provide wide viewing angles. Also provided are methods of using an adjustable particle beam in combination with a mask to generate multi-domains alignments. Such methods are useful for producing liquid crystal cells in general, and for producing the novel multi-domain low twist angle liquid crystal cells of the present invention in particular.
    Type: Application
    Filed: January 28, 2002
    Publication date: July 31, 2003
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Praveen Chaudhari, James P. Doyle, Eileen A. Galligan, James A. Lacey, Shui-Chih Lien, Minhua Lu, Hiroki Nakano, Kei-Hsiung Yang
  • Patent number: 6426786
    Abstract: A single-domain, two-domain or four-domain homeotropic- or tilted homeotropic-alignment liquid crystal display device of either the transmissive-type or reflective-type having a high contrast ratio, a good display quality, and a high photo-stability (and a method of producing the same), includes a homeotropic- or tilted homeotropic-alignment layer which includes an oxide layer prepared by a single oblique evaporation of an activated oxide source. The angle between the evaporation direction and the substrate plane forms an angle from about ±20° to about ±90°, and the thickness of the oxide layer is from about 10 nm to about 200 nm. A method of homeotropic-alignment or tilted homeotropic-alignment of liquid crystals by a single oblique evaporation process is also provided.
    Type: Grant
    Filed: June 1, 1999
    Date of Patent: July 30, 2002
    Assignee: International Business Machines Corporation
    Inventors: Minhua Lu, Kei-Hsiung Yang
  • Publication number: 20020085133
    Abstract: A liquid crystal (LC) lightvalve comprising a twisted nematic LC layer whose molecules are aligned with pixel edges at the mirror backplane, thereby providing improved contrast and efficiency, and reduced visibility of post spacers in black state. The present invention is directed to an LC structure wherein the backplane is rubbed in a direction rectilinear with pixel edges. The LC layer is given the same twist rotation and birefringence as in the conventional TN lightvalve. Polarization control is maintained by illuminating the lightvalve with light whose polarization is rotated by the twist angle relative to the x,y, pixel axes, and by collecting the orthogonally polarized component of the reflected light. The lightvalve top glass is thus rubbed in a direction which is rotated by the twist angle from the horizontal or vertical direction at which the backplane is rubbed.
    Type: Application
    Filed: March 2, 1999
    Publication date: July 4, 2002
    Inventors: KENNETH C. HO, MINHUA LU, ALLAN E. ROSENBLUTH, KEI-HSIUNG YANG
  • Publication number: 20020063830
    Abstract: A method for preparing an alignment layer surface provides a surface on the alignment layer. The surface is bombarded with ions, and reactive gas is introduced to the ion beam to saturate dangling bonds on the surface. Another method for preparing an alignment layer surface provides a surface on the alignment layer. The surface is bombarded with ions and quenched with a reactive component to saturate dangling bonds on the surface.
    Type: Application
    Filed: November 30, 2000
    Publication date: May 30, 2002
    Inventors: Alessandro C. Callegari, Praveen Chaudhari, Fuad E. Doany, James P. Doyle, Eileen A. Galligan, James H. Glownia, Gareth G. Hougham, James A. Lacey, Shui-Chih Lien, Minhua Lu, Alan E. Rosenbluth, Kei-Hsiung Yang
  • Patent number: 6333728
    Abstract: An apparatus provides optimal on-off contrast ratio in a liquid crystal display panel. The apparatus includes a capacitive temperature sensing device for sensing the temperature of liquid crystal display pixels and having an output voltage according to an applied input voltage and a sensed temperature; a monitoring device including differentiator and sample and hold circuit for obtaining a peak voltage corresponding to a maximum change of the voltage output from the temperature sensing device; and a device for measuring a difference between the peak voltage with a predetermined reference voltage and outputting a signal representing the difference. Heat is consequently applied to the liquid crystal display panel in accordance with a measured temperature difference. Advantageously, the capacitive temperature sensing device is formed as part of the liquid crystal display element.
    Type: Grant
    Filed: September 3, 1998
    Date of Patent: December 25, 2001
    Assignee: International Business Machines Corporation
    Inventors: Frank R. Libsch, Kei-Hsiung Yang
  • Patent number: 6332693
    Abstract: An illumination apparatus including: at least two light sources, in which each of the light sources produce independent light beams; a controller for sequentially driving each of the light sources at a high power above their respective maximum rated power, to produce a respective light beam for each light source, and for leaving the remaining light sources at a low power below their respective maximum rated power, such that the time-average of the high and low power levels are set to a predetermined value for each of the light sources; and a combiner and director for sequentially combining each of the light beams from their respective light sources while being driven at high power into a common output beam with a fixed direction. Various combiner and directors are disclosed including tiltable mirrors under the control of the controller as well as optical systems.
    Type: Grant
    Filed: September 7, 2000
    Date of Patent: December 25, 2001
    Assignee: International Business Machines Corporation
    Inventors: Derek Brian Dove, Alan Edward Rosenbluth, Kei-Hsiung Yang
  • Patent number: 6290793
    Abstract: A method of assembling a liquid crystal display device including a pair of substrates combined together with a sealing member and a liquid crystal interposed between the substrates, includes the steps of disposing a plurality of spacers in the area of the sealing member between the substrates, positioning a frame on an outside surface of each substrate, the frame being aligned with the sealing member, and applying pressure to each frame so that a region corresponding to a display area is substantially pressure-free and a uniform cell gap is obtained.
    Type: Grant
    Filed: June 16, 1998
    Date of Patent: September 18, 2001
    Assignee: International Business Machines Corporation
    Inventors: Istvan Lovas, Minhua Lu, Kei-Hsiung Yang
  • Patent number: 6193393
    Abstract: An illumination apparatus including: at least two light sources, in which each of the light sources produce independent light beams; a controller for sequentially driving each of the light sources at a high power above their respective maximum rated power, to produce a respective light beam for each light source, and for leaving the remaining light sources at a low power below their respective maximum rated power, such that the time-average of the high and low power levels are set to a predetermined value for each of the light sources; and a combiner and director for sequentially combining each of the light beams from their respective light sources while being driven at high power into a common output beam with a fixed direction. Various combiner and directors are disclosed including tiltable mirrors under the control of the controller as well as optical systems.
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: February 27, 2001
    Assignee: International Business Machines Corporation
    Inventors: Derek Brian Dove, Alan Edward Rosenbluth, Kei-Hsiung Yang
  • Patent number: 6181400
    Abstract: A twist discotic-type liquid-crystal or liquid-crystalline film with negative birefringence is as a compensation film for either single-domain or two-domain liquid crystal display cells to achieve better view-angle characteristics, less color-shift as a function of applied voltage, and faster response times than uncompensated 90°-twist single-domain or two-domain cells.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: January 30, 2001
    Assignee: International Business Machines Corporation
    Inventors: Kei-Hsiung Yang, Minhua Lu
  • Patent number: 6181398
    Abstract: An LCD reflection display array implementing two or more layers of reflecting front surface mirrors with an upper layer mirror(s) having absorbing back surface(s). The mirror surfaces associated with each pixel are electrically connected to the pixel output electrode. The lower mirrors are appropriately positioned in the three dimensions to achieve nearly 100% aperture fill.
    Type: Grant
    Filed: September 3, 1998
    Date of Patent: January 30, 2001
    Assignee: International Business Machines Corporation
    Inventors: Frank R. Libsch, Kei-Hsiung Yang, James Lawrence Sanford
  • Patent number: 6126768
    Abstract: A method of assembling a liquid crystal display device including a pair of substrates combined together with a sealing member and a liquid crystal interposed between the substrates, includes the steps of disposing a plurality of spacers in the area of the sealing member between the substrates, positioning a frame on an outside surface of each substrate, the frame being aligned with the sealing member, and applying pressure to each frame so that a region corresponding to a display area is substantially pressure-free and a uniform cell gap is obtained.
    Type: Grant
    Filed: June 16, 1998
    Date of Patent: October 3, 2000
    Assignee: International Business Machines Corporation
    Inventors: Istvan Lovas, Minhua Lu, Kei-Hsiung Yang
  • Patent number: 5940155
    Abstract: An optical compensation arrangement using tilted-optical-axis compensation films with negative birefringence for low-twist-angle nematic liquid crystal cells to achieve better viewing angle characteristics than a regular 90.degree.-twist TN cell, with similar high contrast ratio and brightness as the regular TN cell near normal incidence at a comparable operating voltage.
    Type: Grant
    Filed: September 4, 1997
    Date of Patent: August 17, 1999
    Assignee: International Business Machines Corporation
    Inventors: Kei-Hsiung Yang, Kun-Wei Lin, Han-Ping David Shieh
  • Patent number: 5936697
    Abstract: We invent a self-compensated twist nematic (SCTN) mode for reflective light valves with high optical efficiency nearly 100% and it has a saturation voltage below about 3 V and a relatively large tolerance in cell-gap non-uniformity compared to other prior arts. The invented SCTN mode is especially suitable for reflective light valves driven by active matrices fabricated on Si-wafers.
    Type: Grant
    Filed: June 7, 1996
    Date of Patent: August 10, 1999
    Assignee: International Business Machines Corporation
    Inventor: Kei-Hsiung Yang
  • Patent number: 5883687
    Abstract: A liquid crystal (LC) cell having LC phase gratings is disclosed. The LC cell includes alternating strips of a first single domain LC material having a twist angle with a magnitude and a positive sign, and a second single domain LC material having a twist angle with the same magnitude and a negative sign. The magnitude of the twist angle is approximately from 45 to 70 degrees. The first and second LC materials are twisted nematic LC materials or ferro-electric LC materials. The liquid crystal phase gratings operate preferably in a normally-black condition with low operating voltages of below 3 V and high optical diffraction efficiencies. The LC cell is used in reflective or transmissive spatial light modulators of displays.
    Type: Grant
    Filed: April 2, 1997
    Date of Patent: March 16, 1999
    Assignee: International Business Machines Corporation
    Inventors: Minhua Lu, Kei-Hsiung Yang
  • Patent number: 5870164
    Abstract: A twisted nematic liquid crystal (TNLC) cell used in reflective spatial light modulators (SLMs) of displays is disclosed. The TNLC cell includes front and rear substrates, and a TNLC material having a thickness d and a left-handed or right-handed twist angle .phi.. The TNLC material is sandwiched between the front and rear substrates, and the twist angle .phi. is approximately from 46.degree. to 62.degree.. A direction of directors of the TNLC material located nearest the front substrate forms an initial angle .beta. with a direction of linearly polarized light incident thereon. The initial angle .beta. is approximately from -6.degree. to 60.degree.. A birefringence .DELTA.n of the TNLC material times the thickness d is between approximately 0.7.lambda. to 1.25.lambda., where .lambda. is a wavelength of light incident on the front substrate.
    Type: Grant
    Filed: June 20, 1997
    Date of Patent: February 9, 1999
    Assignee: International Business Machines Corporation
    Inventors: Minhua Lu, Robert Lee Melcher, James Lawrence Sanford, Kei-Hsiung Yang
  • Patent number: 5831710
    Abstract: A structural principle is described for control of the gap and the area around the periphery of a liquid crystal display by the formation of an insulating layer out of which, gap dimension maintaining posts and contaminant diffusion inhibiting segmented walls, remain after the display area is etched back out of the layer.
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: November 3, 1998
    Assignee: International Business Machines Corporation
    Inventors: Evan G. Colgan, Minhua Lu, Robert Lee Melcher, James Lawrence Sanford, Kei-Hsiung Yang
  • Patent number: 5818563
    Abstract: A spatial light modulator designed to use a minimum area on the surface of a silicon substrate. This invention comprises a silicon substrate on a back plate with a glass cover that is used to seal liquid crystal between the glass cover and the silicon substrate. Most importantly, the glue seal formed to contain the liquid crystal material is between the cover glass plate and the Si substrate on only one side and the back plate on the remaining three sides. This structure allows a smaller semiconductor substrate to be used.
    Type: Grant
    Filed: September 9, 1997
    Date of Patent: October 6, 1998
    Assignee: IBM Corporation
    Inventors: Evan George Colgan, Robert Lee Melcher, Teruhiro Nakasogi, Chandrasekhar Narayan, James Lawrence Sanford, Kei-Hsiung Yang