Patents by Inventor Junichi Hirakata

Junichi Hirakata 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: 20020047970
    Abstract: To improve optical transmission efficiency without reducing optical reflection efficiency.
    Type: Application
    Filed: November 20, 2001
    Publication date: April 25, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Kikuo Ono, Junichi Hirakata, Takahiro Ochiai, Ryuutaro Oke
  • Publication number: 20020036608
    Abstract: A liquid crystal display device includes a liquid crystal display panel and a lighting device. The lighting device is supplied with alternately a first current during a period t1 and a second current during a second period t2 such that electric power E1 is lower than electric power E2. E1 is defined as (t1×ip-p(1)×Vp-p(1))/2+(t2×ip-p(2)×Vp-p(2))/2, where ip-p(1)=a peak-to-peak value of the first current, Vp-p(1)=a peak-to-peak value of a voltage across the light source during the period t1, ip-p(2)=a peak-to-peak value of the second current, and Vp-p(2)=a peak-to-peak value of a voltage across the light source during the period t2. E2 is defined as (t1+t2)×Ieff×Veff, where Ieff and Veff are effective values of the current and voltage of the light source, respectively.
    Type: Application
    Filed: August 23, 2001
    Publication date: March 28, 2002
    Applicant: Hitachi, Ltd. and Hitachi Device Engineering Co., Ltd.
    Inventors: Junichi Hirakata, Kikuo Ono, Akira Shingai
  • Patent number: 6356331
    Abstract: A liquid crystal display device includes a pixel electrode and a counter electrode which are respectively disposed in different layers in a liquid crystal-side pixel area of one of transparent substrates disposed to oppose each other with a liquid crystal interposed therebetween. The counter electrode causes an electric field having a component parallel to the transparent substrates to be generated between the counter electrode and the pixel electrode. One of the pixel electrode and the counter electrode is formed on a side closer to the liquid crystal than the other electrode is to the liquid crystal, and the other electrode is formed of a transparent electrode extended outwardly from at least a periphery of an area on which the one electrode is superposed.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: March 12, 2002
    Assignee: Hitachi Ltd.
    Inventors: Kikuo Ono, Makoto Yoneya, Tsunenori Yamamoto, Junichi Hirakata, Yoshiaki Nakayoshi
  • Patent number: 6275276
    Abstract: A liquid crystal display having a pair of substrates having electrodes on opposing surfaces thereof, at least one of the substrates being transparent. A continuous liquid crystal layer is sandwiched between the pair of substrates and the liquid crystal layer includes first and second liquid crystal gel layers each with polymer enabling alignment. A direction of orientation of the liquid crystal molecules included in the first liquid crystal gel layer is orthogonal to a direction of orientation of the liquid crystal molecules included in the second liquid crystal gel layer.
    Type: Grant
    Filed: May 30, 2000
    Date of Patent: August 14, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Komura, Yuji Mori, Junichi Hirakata, Masahiko Ando, Osamu Itou, Ikuo Hiyama
  • Patent number: 6191833
    Abstract: A liquid crystal display device with a back-light unit excellent in viewing characteristics while improving the use efficiency of rays of light emitted therefrom is provided. The device includes at least a liquid crystal panel including a liquid crystal layer as sandwiched between a pair of spatially opposed substrates at least one of which has electrodes thereon, an upper polarization plate and lower polarization plate laid out to retain the liquid crystal panel therebetween, an illumination light source in the from of a back-light device for use in illuminating the liquid crystal panel from the back side thereof, and a prism sheet provided at an upper surface of the back-light device, wherein a total reflection film is inserted between the liquid crystal panel and the back-light device so as to reflect light from the prism sheet which is reflected in the prism sheet.
    Type: Grant
    Filed: December 16, 1999
    Date of Patent: February 20, 2001
    Assignee: Hitachi, Ltd.
    Inventor: Junichi Hirakata
  • Patent number: 6133970
    Abstract: A liquid crystal display has excellent viewing angle characteristics and prevents any reduction of transmittance.
    Type: Grant
    Filed: April 8, 1999
    Date of Patent: October 17, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Junichi Hirakata, Toru Sasaki, Junichi Ohwada
  • Patent number: 6072552
    Abstract: A liquid crystal layer comprising a liquid crystal display has first and second liquid crystal gel layers orientated so that polymer threads are of fixed directions within a dichroic liquid crystal. The direction of orientation of the polymer threads included in the first liquid crystal gel layer and the direction of orientation of the polymer threads included in the second liquid crystal gel layer are orthogonal with respect to each other.
    Type: Grant
    Filed: April 2, 1998
    Date of Patent: June 6, 2000
    Assignee: Hitachi, Ltd.
    Inventors: Shinichi Komura, Yuji Mori, Junichi Hirakata, Masahiko Ando, Osamu Itou, Ikuo Hiyama
  • Patent number: 5835175
    Abstract: A color STN-LCD having preferable display quality and decreased manufacturing cost uses a liquid crystal display apparatus which includes a liquid crystal layer having a twist angle in a range from 200.degree. and less than 360.degree., a retardation of the liquid crystal layer in a range of 0.80 .mu.m.about.0.90 .mu.m, an azimuth of transmittance axis of the upper polarizer in a range of 30.degree..about.70.degree., an azimuth of the transmittance axis of the lower polarizer in a range of 60.degree..about.90.degree., an azimuth of the slow axis of the upper phase plate in a range of 150.degree..about.190.degree., an azimuth of the slow axis of the lower phase plate in a range of 30.degree..about.80.degree., a retardation of the upper phase plate at a wave length of 550 nm in a range of 200 nm.about.300 nm, and a retardation of the lower phase plate at a wave length of 550 nm in a range of 500 nm.about.620 nm.
    Type: Grant
    Filed: January 5, 1996
    Date of Patent: November 10, 1998
    Assignees: Hitachi, Ltd., Hitachi Device Engineering, Co. Ltd.
    Inventors: Osamu Itoh, Katsumi Kondo, Junichi Hirakata, Yuka Utsumi, Naoki Kikuchi, Yoshiaki Nakamura
  • Patent number: 5519523
    Abstract: A liquid crystal display device comprising: (a) a liquid crystal layer arranged between substrates each having an electrode; (b) a pair of polarizers arranged so as to sandwich the liquid crystal layer; (c) a birefringent medium arranged between the liquid crystal layer and at least one of the polarizers, when a voltage is applied so that liquid crystal molecules at boundary regions facing said substrates have different tilt angles from other molecules, retardation in said birefringent medium being equal or close to remaining retardation due to the liquid crystal molecules at boundary regions, and the slow axis of said birefringent medium being set for an angle to compensate for said remaining retardation; and (d) control means for changing transmission of said liquid crystal layer by applying voltages of two or more values between said electrodes.
    Type: Grant
    Filed: November 6, 1992
    Date of Patent: May 21, 1996
    Assignees: Hitachi, Ltd., Hitachi Device Engineering Co., Ltd.
    Inventors: Hitomi Madokoro, Ikuo Hiyama, Junichi Hirakata, Hidetoshi Abe, Katsumi Kondo, Masaaki Kitajima, Shinichi Komura, Kenkichi Suzuki, Osamu Itoh, Naoki Kikuchi
  • Patent number: 5220447
    Abstract: A liquid crystal display device comprising: a liquid crystal display element formed by holding, between two substrates at least one of which has a light-permeable electrode, a liquid crystal layer in which liquid crystal molecules of a nematic liquid crystal having positive dielectric anisotropy and containing an optically active substance has a helical axis perpendicular to the substrates between the substrates and are helically oriented, and the liquid crystal molecules between the substrates have a twist angle of 180 to 270 degrees, and a phase plate formed by stacking water surface development films of an organic polymer with changing the orientation axes thereof at a constant angle, wherein the contrast ratio, a ratio between brightness in white display and brightness in black display, is remarkably excellent over that of a device obtained by stacking plastic films, and the transmissivity, a quotient of background brightness and light source brightness, is equivalent to that of a conventional double laye
    Type: Grant
    Filed: March 16, 1990
    Date of Patent: June 15, 1993
    Assignees: Hitachi, Ltd., Denko Corporation
    Inventors: Hisao Yokokura, Teruo Kitamura, Akio Mukoh, Junichi Hirakata, Yasuhiko Kando, Isoji Sakai, Yasuo Fujimura, Noboru Masutani
  • Patent number: 5194973
    Abstract: A liquid crystal display device characterized in comprising a set of substrates facing each other at least one of which is transparent, transparent electrodes provided respectively to each facing plane of the substrates, a light absorbing layer held between the transparent electrodes, and an electric power source for applying electric field to the light absorbing layer, and that the light absorbing layer is composed of two layers, each of the layers has dichroism, average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally, and the average light absorbing axis of the each layers changes the axis direction by applying of electric field. In accordance with the present invention, the liquid crystal display device having eye-tireless bright display, long life time, and electric power saving character is realized.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: March 16, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masato Isogai, Teruo Kitamura, Katsumi Kondo, Junichi Hirakata, Shinichi Komura
  • Patent number: 5157526
    Abstract: The polarizer of the present invention is composed of mediums having different refractive indices, by which ordinary light in incidented light is wholly reflected at a boundary between laminated medium I and medium II and extraordinary light is transmitted through the medium II. The medium II is so arranged as to be almost 45.degree. to the light axis, and thickness of the medium II is selected as a value with which the medium II works as a half wave length plate to the transmitting light. The polarizer, which has high transparency by reduction of absorption and is able to make most of incident light be similarly polarized light, is obtained. A polarizer for and apparatus for bright liquid crystal display, which is able to be enlarged to a large size display without light absorption, can be provided.
    Type: Grant
    Filed: July 1, 1991
    Date of Patent: October 20, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Katsumi Kondo, Junichi Hirakata, Osamu Ito, Teruo Kitamura, Shuichi Ohara, Naoki Kikuchi, Masato Shimura