Patents by Inventor Tadaaki Hirai

Tadaaki Hirai 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).

  • Patent number: 8415662
    Abstract: An X-ray detector 1 includes: an X-ray conversion layer 17 which is made of amorphous selenium and absorbs incident radiation and generates charges; a common electrode 23 provided on a surface on the side on which radiation is made incident of the X-ray conversion layer 17; and a signal readout substrate 2 on which a plurality of pixel electrodes 7 for collecting charges generated by the X-ray conversion layer 17 are arrayed, and further includes: an electric field relaxation layer 13 provided between the X-ray conversion layer 17 and the signal readout substrate 2 and containing arsenic and lithium fluoride; a crystallization suppressing layer 11 provided between the electric field relaxation layer 13 and the signal readout substrate 2 and containing arsenic; and a first thermal property enhancement layer 15 provided between the electric field relaxation layer 13 and the X-ray conversion layer 17 and containing arsenic.
    Type: Grant
    Filed: July 23, 2009
    Date of Patent: April 9, 2013
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Koichi Ogusu, Osamu Nakane, Yasunori Igasaki, Yoshinori Okamura, Tadaaki Hirai
  • Publication number: 20110163305
    Abstract: An X-ray detector 1 includes: an X-ray conversion layer 17 which is made of amorphous selenium and absorbs incident radiation and generates charges; a common electrode 23 provided on a surface on the side on which radiation is made incident of the X-ray conversion layer 17; and a signal readout substrate 2 on which a plurality of pixel electrodes 7 for collecting charges generated by the X-ray conversion layer 17 are arrayed, and further includes: an electric field relaxation layer 13 provided between the X-ray conversion layer 17 and the signal readout substrate 2 and containing arsenic and lithium fluoride; a crystallization suppressing layer 11 provided between the electric field relaxation layer 13 and the signal readout substrate 2 and containing arsenic; and a first thermal property enhancement layer 15 provided between the electric field relaxation layer 13 and the X-ray conversion layer 17 and containing arsenic.
    Type: Application
    Filed: July 23, 2009
    Publication date: July 7, 2011
    Applicant: Hammamatsu Photonics K.K.
    Inventors: Koichi Ogusu, Osamu Nakane, Yasunori Igasaki, Yoshinori Okamura, Tadaaki Hirai
  • Patent number: 7217929
    Abstract: When the distal end of a radiation detection probe (2) is directed toward a place to be measured, pointer light emitted by a light-emitting device (7) sequentially passes through a transmission window (5C) of a radiation detection element (5) and a projection window (3E) of a probe cover (3) to be emitted onto the place to be measured. This pointer light clearly indicates the place as a bright spot. The radiation from the place passes through the distal end of the probe cover (3) to be collimated by a radiation-introducing window (4A) of a side shield (4), and then enters the radiation detection element (5). The dose of the radiation is detected in this way.
    Type: Grant
    Filed: August 20, 2003
    Date of Patent: May 15, 2007
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Tadaaki Hirai, Yasuhiro Tomita, Masanori Kinpara, Michiatsu Nakada, Yuji Shirayanagi, Shinjiro Matsui
  • Publication number: 20050230628
    Abstract: When the distal end of a radiation detection probe (2) is directed toward a place to be measured, pointer light emitted by a light-emitting device (7) sequentially passes through a transmission window (5C) of a radiation detection element (5) and a projection window (3E) of a probe cover (3) to be emitted onto the place to be measured. This pointer light clearly indicates the place as a bright spot. The radiation from the place passes through the distal end of the probe cover (3) to be collimated by a radiation-introducing window (4A) of a side shield (4), and then enters the radiation detection element (5). The dose of the radiation is detected in this way.
    Type: Application
    Filed: August 20, 2003
    Publication date: October 20, 2005
    Inventors: Tadaaki Hirai, Yasuhiro Tomita, Masanori Kinpara, Michiatsu Nakada, Yuji Shirayanagi, Shinjiro Matsui
  • Patent number: 5818064
    Abstract: A method and apparatus is provided for picking up and displaying a stereoscopic image from an object permeated with radioactive rays. A plurality of radioactive rays which are non-parallel with each other are directed substantially simultaneously onto an object to generate a plurality of superimposed images of the object. The superimposed images of the object are divided into a plurality of discrete partial images formed on a pickup surface, so that each point of the object will be included in a plurality of the partial images, with the partial images showing the same point being spatially separated from one another on the pickup surface. A stereoscopic image of the object is then reconstructed by processing the partial images so that partial images generated by each of the sources of the radioactive rays will be respectively used to generate separate images of the object to form the stereoscopic image of the object.
    Type: Grant
    Filed: June 7, 1996
    Date of Patent: October 6, 1998
    Assignee: Hitachi, Ltd.
    Inventors: Akihiko Kohgami, Tadaaki Hirai, Keiji Umetani
  • Patent number: 5583345
    Abstract: A method and apparatus is provided for picking up and displaying a stereoscopic image from an object permeated with radioactive rays. In accordance with the method, a plurality of radioactive rays which are non-parallel with each other are directed substantially simultaneously onto an object to generate a plurality of superimposed images of the object. The superimposed images of the object are divided into a plurality of discrete partial images formed on a pickup surface, so that each point of the object will be included in a plurality of the partial images, with the partial images showing the same point being spatially separated from one another on the pickup surface, A stereoscopic image of the object is then reconstructed by processing the partial images so that partial images generated by each of the sources of the radioactive rays will be respectively used to generate separate images of the object to form the stereoscopic image of the object.
    Type: Grant
    Filed: September 7, 1994
    Date of Patent: December 10, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Akihiko Kohgami, Tadaaki Hirai, Keiji Umetani
  • Patent number: 5384597
    Abstract: An image pickup tube is provided with the third electrode to control the potential of the region which is not scanned by an electron beam in the image pickup tube target section including a target electrode and a photo-conductive film. A method for operating this image pickup tube is also disclosed. Thus, undesired image phenomena which are generated when the image pickup tube is used with a relatively high target voltage, e.g., image distortion, shading, a waterfall phenomenon and image inversion phenomenon can be suppressed, thereby realizing a high sensitivity image pickup tube.
    Type: Grant
    Filed: May 16, 1991
    Date of Patent: January 24, 1995
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Kenji Sameshima, Tatsuo Makishima, Tadaaki Hirai, Yukio Takasaki, Misao Kubota, Kenkichi Tanioka, Keiichi Shidara
  • Patent number: 5233265
    Abstract: A photoconductive device having a photoconductive layer which includes an amorphous semiconductor layer capable of charge multiplication in at least a part thereof is disclosed. The method of operating such a photoconductive device is also disclosed. By using the avalanche effect of the amorphous semiconductor layer, it is possible to realize a highly sensitive photoconductive device while maintaining low lag property. In one aspect of the present invention, the amorphous semiconductor layer is amorphous Se. In another aspect of the present invention, the amorphous semiconductor layer is composed mainly of tetrahedral elements including at least an element of hydrogen or halogens. When using the amorphous semiconductor layer composed mainly of tetrahedral elements, the charge multiplication effect is produced mainly in the interior of the amorphous semiconductor, and thus it is possible to obtain a thermally stable photoconductive device having a high sensitivity while keeping a good photoresponse.
    Type: Grant
    Filed: August 1, 1990
    Date of Patent: August 3, 1993
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Yukio Takasaki, Kazutaka Tsuji, Tatsuo Makishima, Tadaaki Hirai, Sachio Ishioka, Tatsuro Kawamura, Keiichi Shidara, Eikyu Hiruma, Kenkichi Tanioka, Junichi Yamazaki, Kenji Sameshima, Hirokazu Matsubara, Kazuhisa Taketoshi, Mitsuo Kosugi, Shiro Suzuki, Takashi Yamashita, Masaaki Aiba, Yoshizumi Ikeda, Tsuyoshi Uda, Naohiro Goto, Yasuhiko Nonaka, Eisuke Inoue, Hirofumi Ogawa
  • Patent number: 5218264
    Abstract: An image pick-up apparatus is disclosed which includes a target portion having a photoconductive film on a substrate and a target electrode and reads video information converted into an electric signal in the photoconductive film by an electron beam. An insulating region is provided for the target portion such that carrier generated in an ineffective scanned region (a target region corresponding to an area not scanned by the electron beam) does not appear on a surface of the target portion.
    Type: Grant
    Filed: January 31, 1990
    Date of Patent: June 8, 1993
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Tadaaki Hirai, Hirofumi Ogawa, Kenji Sameshima, Yukio Takasaki, Takaaki Unnai, Junichi Yamazaki, Misao Kubota, Kenkichi Tanioka, Eikyu Hiruma
  • Patent number: 5196702
    Abstract: An optically reading type photo-sensor for reading out an information signal of a signal light with a signal reading light includes a first photoconductor (101) and a second photoconductor (102) interposed between two electrodes (104 and 105); an intermediate region (103) disposed between those two photoconductors for storing and recombining carriers; and an optical source (107) for emitting a signal reading light for uninformalizing the potential in said second photoconductor (102), whereby a successive signal reading can be accomplished without any special preparations for the incidence of the signal light. The photo-sensor can be applied to a variety of imaging devices.
    Type: Grant
    Filed: December 11, 1991
    Date of Patent: March 23, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Kazutaka Tsuji, Tadaaki Hirai, Yukio Takasaki, Haruo Itoh, Tetshuhiko Takahashi, Kenichi Okajima
  • Patent number: 5101255
    Abstract: Disclosed is a photoelectric conversion device which comprises: a photoconductive layer made of amorphous semiconductor material which shows charge multiplication and which converts photo signals into electric signals; and a substrate having electric circuits or the like (for example switching elements) for reading the electric signals. The amorphous semiconductor material used according to the invention shows the charge multiplication action under predetermined intensity of electric field so that a high sensitive photoelectric conversion device having a gain which is not smaller than 1 is realized.
    Type: Grant
    Filed: July 24, 1989
    Date of Patent: March 31, 1992
    Inventors: Sachio Ishioka, Yukio Takasaki, Tadaaki Hirai, Kazutaka Tsuji, Tatsuo Makishima, Yasuhiko Nonaka, Tatsuro Kawamura, Takashi Yamashita, Kazuhisa Taketoshi, Keiichi Shidara, Fumihiko Ando, Kenkichi Tanioka
  • Patent number: 5070272
    Abstract: A photoconductive device having a transparent substrate, a transparent conductive film, a photoconductive film and a layer of an insulator provided on at least part of the substrate and of high thermal conductivity, and a method of operating the photoconductive device. Thus, especially, the temperature of a photoconductive film of an imaging device typical of an image pick-up tube or the photoconductive device which may be a one- or a two-dimensional image sensor or a photocell can be controlled precisely and efficiently.
    Type: Grant
    Filed: July 3, 1990
    Date of Patent: December 3, 1991
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Takeshi Kikawa, Kazutaka Tsuji, Kenji Sameshima, Tadaaki Hirai, Junichi Yamazaki, Misao Kubota, Keiichi Shidara
  • Patent number: 5023896
    Abstract: An X-ray television apparatus applies an X-ray to an object to be inspected, converts the X-ray projection image of the object into an optical image by a fluorescent screen or an X-ray image intensifier, picks up the optical image by a TV camera, displays the video signal obtained by a TV monitor for fluoroscopic monitoring, and records radiograph of the object by using the video signal. Avalanche multiplication is caused on the photoconductive layer of the image pick-up tube of the TV camera so as to enable monitoring or imaging with high sensitivity at a low X-ray dose rate.
    Type: Grant
    Filed: May 25, 1989
    Date of Patent: June 11, 1991
    Assignee: Hitachi-Medical Corporation
    Inventors: Hisatake Yokouchi, Yukio Takasaki, Tadaaki Hirai, Kouichi Koike, Masayuki Tsuneoka, Yoichi Onodera, Takakazu Funo
  • Patent number: 5021705
    Abstract: An image pick-up tube and a method of fabricating an image pick-up tube and a target section used therewith, in which the target includes at least a conductive film and a photoconductive film on a substrate for photo-electric conversion, and a signal from the target section is read by an electron beam scanning system. At least a part of the surface area outside the effective scanning region of the electron beam scanning side of the target section is formed of a secondary electron emission dampening layer.
    Type: Grant
    Filed: May 24, 1989
    Date of Patent: June 4, 1991
    Assignees: Hitachi Ltd., Nippon Hoso Kyokai
    Inventors: Masanao Yamamoto, Takaaki Unnai, Shigeru Ehata, Tadaaki Hirai, Kenji Sameshima, Eikiyu Hiruma, Shirou Suzuki, Kenkichi Tanioka, Junichi Yamazaki, Keiichi Shidara
  • Patent number: 4982095
    Abstract: This invention relates to a multi-element type radiation detector for an X-ray CT scanner system wherein a plurality of scintillator blocks that are isolated either optically or radiation-wise from one another are arranged integrally, and a photo-diode consisting of an amorphous silicon layer for converting the emission of each scintillator is formed on the surface of each scintillator block by thin film technique.
    Type: Grant
    Filed: September 1, 1988
    Date of Patent: January 1, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Tetsuhiko Takahashi, Hirosh Takeuch, Toshikazu Shimada, Haruo Itoh, Tadaaki Hirai, Kenji Maio, Kenichi Okajima, Minoru Yoshida, Hideaki Yamamoto
  • Patent number: 4980736
    Abstract: A photoelectric conversion device using an amorphous material composed mainly of tetrahedral elements including at least an element of hydrogen and halogens as semiconductor material is disclosed. When a strong electric field is applied to a layer formed by using this amorphous semiconductor, a charge multiplication effect is produced mainly in the interior of the amorphous semiconductor and thus it is possible to obtain a thermally stable photoelectric conversion device having a high sensitivity while keeping a good photoresponse.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: December 25, 1990
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Yukio Takasaki, Kazutaka Tsuji, Tatsuo Makishima, Tadaaki Hirai, Sachio Ishioka, Tatsuro Kawamura, Keiichi Shidara, Eikyu Hiruma, Kenkichi Tanioka, Junichi Yamazaki, Kenji Sameshima, Hirokazu Matsubara, Kazuhisa Taketoshi
  • Patent number: 4952839
    Abstract: A photoconductive device having a photoconductive layer which includes an amorphous semiconductor layer capable of charge multiplication in at least a part thereof is disclosed. The method of operating such a photoconductive device is also disclosed. By using the avalanche effect of the amorphous semiconductor layer, it is possible to realize a highly sensitive photoconductive device while maintaining low lag property.
    Type: Grant
    Filed: October 12, 1989
    Date of Patent: August 28, 1990
    Assignees: Hitachi, Ltd, Nippon Hoso Kyokai
    Inventors: Kenkichi Tanioka, Mitsuo Kosugi, Junichi Yamazaki, Keiichi Shidara, Kazuhisa Taketoshi, Tatsuro Kawamura, Eikyuu Hiruma, Shiro Suzuki, Takashi Yamashita, Masaaki Aiba, Yochizumi Ikeda, Tadaaki Hirai, Yukio Takasaki, Sachio Ishioka, Tatsuo Makishima, Kenji Sameshima, Tsuyoshi Uda, Naohiro Goto, Yasuhiko Nonaka, Eisuke Inoue, Kazutaka Tsuji, Hirofumi Ogawa
  • Patent number: 4900975
    Abstract: A target of an image pickup tube is formed by laminating at least a transparent conductive film, an amorphous layer consisting essentially of silicon, and an amorphous layer consisting essentially of selenium in the above order on a light-transmitting substrate.
    Type: Grant
    Filed: June 29, 1987
    Date of Patent: February 13, 1990
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Yasuharu Shimomoto, Sachio Ishioka, Yukio Takasaki, Tadaaki Hirai, Kazutaka Tsuji, Tatsuo Makishima, Hirokazu Matsubara, Kenji Sameshima, Junichi Yamazaki, Kenkichi Tanioka, Mitsuo Kosugi, Keiichi Shidara, Tatsuro Kawamura, Eikyuu Hiruma, Takashi Yamashita
  • Patent number: 4888521
    Abstract: A photoconductive device having a photoconductive layer which includes an amorphous semiconductor layer capable of charge multiplication in at least a part thereof is disclosed. The method of operating such a photoconductive device is also disclosed. By using the avalanche effect of the amorphous semiconductor layer, it is possible to realize a highly sensitive photoconductive device while maintaining low lag property.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: December 19, 1989
    Assignees: Hitachi Ltd., Nippon Hoso Kyokai
    Inventors: Kenkichi Tanioka, Keiichi Shidara, Tatsuro Kawamura, Junichi Yamazaki, Eikyuu Hiruma, Kazuhisa Taketoshi, Shiro Suzuki, Takashi Yamashita, Mitsuo Kosugi, Yochizumi Ikeda, Masaaki Aiba, Tadaaki Hirai, Yukio Takasaki, Sachio Ishioka, Tatsuo Makishima, Kenji Sameshima, Tsuyoshi Uda, Naohiro Goto, Yasuhiko Nonaka, Eisuke Inoue, Kazutaka Tsuji, Hirofumi Ogawa
  • Patent number: 4883562
    Abstract: A method of making an image pickup tube target (FIG. 1A), etc., using an amorphous photoconductive layer. When an electrode, an amorphous semiconductor layer, etc., are provided on a substrate, the steps of ion etching away a surface of the substrate and forming the electrode are performed so that a target (FIG. 1A) is produced in which no defects are substantially caused in a reproduced image even if a high electric field is applied across the target.
    Type: Grant
    Filed: January 26, 1989
    Date of Patent: November 28, 1989
    Assignees: Hitachi, Ltd., Nippon Hoso Kyokai
    Inventors: Hirofumi Ogawa, Kenji Sameshima, Tadaaki Hirai, Takaaki Unnai, Masanao Yamamoto, Keiichi Shidara, Junichi Yamazaki, Eikiyu Hiruma, Shirou Suzuki