Patents by Inventor Tetsu Ohishi

Tetsu Ohishi 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: 20070273969
    Abstract: Image disturbance called speckle noise occurs when an image generator has a small effective screen size and a projection lens has a small effective diameter. The present invention is intended to reduce speckle noise. In an optical projector, a viewing angle enlarging ember (60) for enlarging viewing angle or a scattering member (28) for scattering image light is disposed near an image display device (18), such as a liquid crystal panel. Speckle noise can be reduced, suppressing the deterioration of resolution and contrast.
    Type: Application
    Filed: August 3, 2007
    Publication date: November 29, 2007
    Applicant: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Patent number: 7298080
    Abstract: A flat type display device is provided which is capable of accurately and easily assembling a spacer when arranging the spacer while reducing the danger of damaging the metal back. In the display device, a plurality of fine holes each having a fluorescent materials are formed on a light transparency substrate and a metal sheet is arranged by a black oxide film formed on the surface of the light transparency substrate side so as to obtain a light absorbing layer. A plurality of concave portions are provided on a surface of the metal sheet of the rear substrate side. A metal back having an openings corresponding to predetermined areas containing each of the concave portions is superimposed on the metal sheet, thereby constituting an acceleration electrode of two-layer structure. The spacer is inserted into the concave portion on the metal sheet exposed in the opening of the metal back.
    Type: Grant
    Filed: August 31, 2004
    Date of Patent: November 20, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Yoshie Kodera, Masakazu Sagawa, Toshiaki Kusunoki, Tetsu Ohishi, Yuichi Sawai
  • Publication number: 20070216670
    Abstract: The present invention ensures the efficient radiation of heat of a flat display panel without increasing a space outside a display screen of the flat display panel. A periphery of a reinforcing member adhered to a back surface of the flat display panel is folded in an L-shape and a driver IC is brought into contact with the folded portion.
    Type: Application
    Filed: March 14, 2007
    Publication date: September 20, 2007
    Inventors: Yasuharu Yatsu, Atsuo Osawa, Mikio Shiraishi, Yoshie Kodera, Tetsu Ohishi
  • Patent number: 7271783
    Abstract: A back substrate has a plurality of electron emission elements. A display substrate comprises an optically transparent substrate disposed opposite to the back substrate; an accelerating electrode formed on the inner face of the optically transparent substrate for accelerating electron beams emitted from the electron emission elements; and luminescent materials excited by the electron beams to emit light toward the outer face of the optically transparent substrate. A frame member supports the back substrate and display substrate on their peripheries. A vacuum chamber is defined by the back substrate, display substrate, and frame member. A conductor electrically connected to the accelerating electrode is drawn out to the outside of the vacuum chamber. A high voltage connector for supplying an accelerating voltage to the conductor is removably connected to the conductor.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: September 18, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Yoshie Kodera, Tetsu Ohishi, Nobuo Masuoka, Akinori Maeda, Junichi Ikoma, Hidenao Kubota
  • Patent number: 7261421
    Abstract: Image disturbance called speckle noise occurs when an image generator has a small effective screen size and a projection lens has a small effective diameter. The present invention is intended to reduce speckle noise. In an optical projector, a viewing angle enlarging ember (60) for enlarging viewing angle or a scattering member (28) for scattering image light is disposed near an image display device (18), such as a liquid crystal panel. Speckle noise can be reduced, suppressing the deterioration of resolution and contrast.
    Type: Grant
    Filed: August 20, 2004
    Date of Patent: August 28, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Patent number: 7245429
    Abstract: A total reflecting prism portion is formed on an image generation source side of a Fresnel lens sheet which constitutes a rear projection type screen. The total reflecting prism portion is formed in an area in which the angle of incidence of a projection image projected from an optical part on the Fresnel lens sheet is at least about 40°. The total reflecting prism portion causes incident light to be outputted as output light at a predetermined output angle by a total reflection phenomenon after a first refraction phenomenon. Further, a refracting prism portion is formed on an image monitoring side of the Fresnel lens sheet. The refracting prism portion is formed in an area opposed to the portion where the total reflecting prism portion is not formed. The refracting prism portion causes incident light to be outputted as output light at a predetermined output angle by a second refraction phenomenon.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: July 17, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Publication number: 20070146877
    Abstract: In a Fresnel screen for displaying an image, comprising, a screen surface, and a reverse surface opposite to the screen surface in a thickness direction of the screen to be prevented from facing to the viewer, the Fresnel screen has first prism surfaces extending to have respective longitudinal arc-shapes juxtaposed with each other as seen in the thickness direction to deflect light beams for forming the image in at least one of directions perpendicular to each other as seen in the thickness direction, and second prism surfaces extending to have respective longitudinal shapes juxtaposed with each other as seen in the thickness direction to deflect at least a part of the light beams in at least one of the directions perpendicular to each other as seen in the thickness direction.
    Type: Application
    Filed: August 30, 2006
    Publication date: June 28, 2007
    Applicant: Hitachi, Ltd.
    Inventors: Daisuke Imafuku, Hiroki Yoshikawa, Tetsu Ohishi
  • Publication number: 20070139623
    Abstract: A projection display is capable of suppressing both the trapezoidal distortion of an enlarged image projected on a screen by oblique projection and aberrations resulting from oblique projection and includes a projection optical system provided with lenses that can be easily manufactured and assembled. The projection optical system for obliquely projecting an image formed by a display device on the screen includes a free curved lens having a rotationally asymmetric free curved surface. The free curved lens has fringing parts having outlines of a shape coinciding with an arc of a circle having the center on the optical axis of the free curved lens.
    Type: Application
    Filed: June 23, 2006
    Publication date: June 21, 2007
    Inventors: Takanori Hisada, Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Naoyuki Ogura
  • Publication number: 20070103604
    Abstract: An image that has been displayed on the display screen of an image generator 1 is first passed through a projection lens section 2 consisting of a front group and a rear group. Next after being reflected on the reflecting surface of a free-form surface mirror 5, the image is further reflected by a planar reflecting mirror 4 and then obliquely projected from the lower section of a projection screen 3 onto the screen 3. The front group of the projection lens section 2 is provided for enlarging the image. In order to correct aberration due to oblique projection onto the projection screen, the rear group uses a free-form surface lens that forms a concave shape with respect to the exit side of light from the lens. The free-form surface mirror 5 corrects trapezoidal distortion due to oblique projection onto the projection screen.
    Type: Application
    Filed: November 3, 2006
    Publication date: May 10, 2007
    Inventors: Hiroki Yoshikawa, Takanori Hisada, Tetsu Ohishi, Koji Hirata, Naoyuki Ogura
  • Publication number: 20070069629
    Abstract: An image display device and its manufacture method are provided which are excellent in mass production at low cost and in reliability with a good quality of an assembled panel main body. In a thin type image display device having electrodes and an envelope accommodating components including the electrodes for displaying an image by electrons emitted from the electrodes, conductive adhesive of a low surface resistance is coated on the inner surface of the envelope or on the surfaces of the components accommodated in the envelope. The conductive adhesive has a surface resistance of 1×1010 ?/? or lower.
    Type: Application
    Filed: August 29, 2006
    Publication date: March 29, 2007
    Applicant: Hitachi, Ltd.
    Inventors: Tetsu Ohishi, Yoshie Kodera, Atsuo Ohsawa, Akinori Maeda
  • Publication number: 20070069630
    Abstract: In an image display device which includes a frame body which is arranged between a back substrate and a face substrate, a phosphor screen which is arranged on the face substrate, and an anode lead line for introducing a high voltage which is arranged between the phosphor screen and a voltage source, the anode lead line is covered with at least a portion of the frame body. According to the present invention, it is possible to obtain an image display device having a prolonged lifetime and capable of performing a high quality display while ensuring the conduction of a high voltage which is applied to a phosphor screen side.
    Type: Application
    Filed: September 27, 2006
    Publication date: March 29, 2007
    Inventors: Yuuichi Kijima, Shigemi Hirasawa, Yoshie Kodera, Tetsu Ohishi
  • Publication number: 20070052341
    Abstract: The invention provides a technology suited to suppress decrease in the brightness of an image while preventing reduction in the contrast of the image caused by external light coming from the outside (from the viewer side of the image) of a screen. An image display surface (screen) of a projection type display device is provided with a front protective sheet including an optical filter member for absorbing specific wavelengths in the external light, especially among peak wavelengths of a three-wavelength fluorescent lamp. Moreover, LED's of three colors are used as a light source for forming an image. At least one of these LED's emits a light of a different wavelength from a peak wavelength that the front protective sheet absorbs. By this configuration, it is possible to prevent reduction in the contrast of an image caused by external light without decreasing the brightness of the image display device.
    Type: Application
    Filed: June 14, 2006
    Publication date: March 8, 2007
    Inventors: Daisuke Imafuku, Hiroki Yoshikawa, Tetsu Ohishi
  • Patent number: 7176876
    Abstract: The present invention provides a bright and high-resolution display apparatus having a dynamic range exceeding the number of gray-scale voltage (or current) outputs, which a signal driver is capable of generating. In accordance with the present invention, a select period, in which a group of pixels on each row is driven, is divided into a plurality of sub-periods. The signal driver supplies a voltage output varying from sub-period to sub-period to selected pixels through a signal electrode. The pixel is capable of expressing various values of a gray scale, the size of which is at least approximately equal to (the number of gray-scale voltage outputs, which the signal driver is capable of generating)×(the number of sub-periods). By changing the ratio of the length of a sub-period to the length of another sub-period or the range of the driving voltage (or current), the dynamic range of the display can be further increased.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: February 13, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Nobuaki Kabuto, Toshimitsu Watanabe, Yoshie Kodera, Mutsumi Suzuki, Tetsu Ohishi
  • Publication number: 20070002281
    Abstract: A fresnel lens sheet has a fresnel center in the vicinity of a lower end, and includes first and second fresnel lens portions respectively formed into concentrically circular shapes. The first fresnel lens portion exists inside a reference circumference, and the second fresnel lens portion exists outside the reference circumference. A conjugate point distance of the second fresnel lens portion is shorter than a conjugate point distance of the first fresnel lens portion. The reference circumference passes through vicinities of cross points between a horizontal centerline, which halves the fresnel lens sheet into upper and lower portions, and left and right ends of the fresnel lens sheet.
    Type: Application
    Filed: June 9, 2006
    Publication date: January 4, 2007
    Applicant: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Takanori Hisada, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Publication number: 20060256433
    Abstract: A total reflecting prism portion is formed on an image generation source side of a Fresnel lens sheet which constitutes a rear projection type screen. The total reflecting prism portion is formed in an area in which the angle of incidence of a projection image projected from an optical part on the Fresnel lens sheet is at least about 40°. The total reflecting prism portion causes incident light to be outputted as output light at a predetermined output angle by a total reflection phenomenon after a first refraction phenomenon. Further, a refracting prism portion is formed on an image monitoring side of the Fresnel lens sheet. The refracting prism portion is formed in an area opposed to the portion where the total reflecting prism portion is not formed. The refracting prism portion causes incident light to be outputted as output light at a predetermined output angle by a second refraction phenomenon.
    Type: Application
    Filed: July 14, 2006
    Publication date: November 16, 2006
    Applicant: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Publication number: 20060227432
    Abstract: The invention provides a projection image display device in which a trapezoidal distortion and/or aberration are restrained when an image is enlarged and projected obliquely onto a screen and an assembling and adjusting are easily done, and a projection optical unit usable for the device. An image generator is connected to an optical system base in such a manner that at least an inclination thereof (on an axis parallel to X axis) with respect to a vertical line and a distance thereof in forward and backward direction (Z axis direction) can be adjusted by an adjusting mechanism. Further, a projecting lens 2 as a first optical system and a free-form curved surface mirror as a second optical system are fixed to the optical system base. The free-form curved surface mirror is rotatable (on an rotary axis parallel to X axis) with respect to the vertical line at a substantial center of the free-form curved surface mirror.
    Type: Application
    Filed: November 17, 2005
    Publication date: October 12, 2006
    Inventors: Hiroki Yoshikawa, Takanori Hisada, Tetsu Ohishi, Koji Hirata, Naoyuki Ogura
  • Publication number: 20060227299
    Abstract: In the image display device, a projection lens including a plurality of lenses for enlarging an image from an image display element is constituted of a front group and a rear group. The rear group includes at least one free-shaped-surface lens including a surface having a rotationally asymmetrical shape. Furthermore, the device includes at least one free-shaped-surface mirror having a rotationally asymmetrical reflection surface. Accordingly, a set can be formed to be compact while correcting trapezoidal distortion and aberration.
    Type: Application
    Filed: October 26, 2005
    Publication date: October 12, 2006
    Inventors: Takanori Hisada, Hiroki Yoshikawa, Tetsu Ohishi, Masahiko Yatsu, Koji Hirata
  • Patent number: 7095169
    Abstract: A flat panel display device capable of reducing charging of phosphors and disposing spacers easily and accurately. The flat panel display device has a rear substrate including an insulating substrate provided with many cold cathode elements for emitting electrons, a display substrate including a light-transmissive substrate disposed to face the rear substrate, and phosphors disposed on the light-transmissive substrate for generating light when excited by electron beams from the cold cathode elements, and a peripheral frame member. Provided on the light-transmissive substrate is a metal sheet perforated with plural fine holes arranged in a matrix configuration and having the phosphors disposed therewithin to form a light-emissive region.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: August 22, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Tetsu Ohishi, Masakazu Sagawa, Yoshie Kodera, Motoyuki Miyata, Akinori Maeda
  • Patent number: 7095558
    Abstract: A total reflecting prism portion is formed on an image generation source side of a Fresnel lens sheet which constitutes a rear projection type screen. The total reflecting prism portion is formed in an area in which the angle of incidence of a projection image projected from an optical part on the Fresnel lens sheet is at least about 40·. The total reflecting prism portion causes incident light to be outputted as output light at a predetermined output angle by a total reflection phenomenon after a first refraction phenomenon. A refracting prism portion is formed on an image monitoring side of the Fresnel lens sheet. The refracting prism portion is formed in an area opposed to the portion where the total reflecting prism portion is not formed. The refracting prism portion causes incident light to be outputted as output light at a predetermined output angle by a second refraction phenomenon.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: August 22, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Koji Hirata, Daisuke Imafuku
  • Publication number: 20060132913
    Abstract: The present invention provides a technology suitable for shortening a depth of a image display apparatus while obtaining a picture of high quality. According to the invention, a total reflection prism portion is provided on a side of a Fresnel lens sheet toward a picture source. The total reflection prism portion reflects an incident light to a direction toward an optic axial center of the Fresnel lens sheet to have the same outgoing. On the other hand, a first refractive prism portion, by which light of a predetermined incident angle or less is refracted to outgo to a direction along an optical axis of the Fresnel lens sheet, and a second refractive prism portion, by which light reflected to the direction toward the optic axial center of the Fresnel lens sheet is changed to the direction along the optical axis.
    Type: Application
    Filed: November 18, 2005
    Publication date: June 22, 2006
    Inventors: Hiroki Yoshikawa, Tetsu Ohishi, Daisuke Imafuku, Koji Hirata