Patents by Inventor Hirokazu Matsubara

Hirokazu Matsubara 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: 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: 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: 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: 4829345
    Abstract: Within an electronic device having a plurality of circuit parts (such as a three-dimensional device), a light transmission system which transfers signals between the circuit parts by the use of light is provided.The light transmission system is formed of a light emitting source which emits light having a desired wavelength, a photoelectric conversion portion which absorbs the light and converts it into an electric signal, and a light traveling path which conveys the light emitted from the light emitting source to the photoelectric conversion portion.Further, each of the light emitting source, the light traveling path and the photoelectric conversion portion is formed of a superlattice structure in which a plurality of materials of unequal energy gaps are layered.
    Type: Grant
    Filed: April 29, 1986
    Date of Patent: May 9, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Sachio Ishioka, Kazutaka Tsuji, Yukio Takasaki, Yasuharu Shimomoto, Hirokazu Matsubara, Tadaaki Hirai
  • Patent number: 4672015
    Abstract: The invention relates to an electrophotographic member which is highly sensitive to the light of long wavelengths. Amorphous silicon is used as a photosensitive base member. A long wavelength sensitizing region has a narrower forbidden band gap width than that of the base member, and consists of at least two semiconductor films that are laminated and that have at least different forbidden band gap widths or different conductivities. An increased number of semiconductor films may, of course, be laminated to constitute the sensitizing region.
    Type: Grant
    Filed: December 16, 1985
    Date of Patent: June 9, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Maruyama, Makoto Fujikura, Hirokazu Matsubara, Toshikazu Shimada
  • Patent number: 4433202
    Abstract: A thin film solar cell formed on a substrate, comprising at least first and second electrodes, at least one of which is capable of passing light, a silicon film interposed between said first and second electrodes, and at least one junction formed in the silicon film for separating electrons and positive holes when the cell is exposed to light, wherein said silicon film comprises a mixed phase consisting of a polycrystalline phase and an amorphous phase, and includes at least about 50% by volume of fibrous crystalline grains, each of said grains having a maximum bottom diameter of about 1 .mu.m and a minimum height of about 50 nm and having its grain boundaries terminated with a monovalent element.The solar cell has a high photoelectric conversion efficiency comparable to that of a single-crystal solar cell, and can be produced at a low cost.
    Type: Grant
    Filed: March 26, 1982
    Date of Patent: February 21, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Maruyama, Toshikazu Shimada, Yasuhiro Shiraki, Yoshifumi Katayama, Hirokazu Matsubara, Akitoshi Ishizaka, Yoshimasa Murayama, Akira Shintani
  • Patent number: 4405879
    Abstract: There is disclosed a photoelectric conversion device comprising a transparent substrate; a transparent conductive film formed on said substrate; a photoconductive layer formed of hydrogenated amorphous silicon as an indispensable component and deposited on said transparent conductive film; and a chalcogen glass film formed on said photoconductive layer, wherein said chalcogen glass film includes at least a chalcogen glass layer formed in an atmosphere of inert gas kept at 1.5.times.10.sup.-2 to 1.5.times.10.sup.-1 Torr. As chalcogen glass is preferably used Sb.sub.2 S.sub.3, As.sub.2 S.sub.3, As.sub.2 Se.sub.3 or Sb.sub.2 Se.sub.3. The chalcogen glass film may be a composite film consisting of plural component layers. This invention is very useful to reduce dark current in an image pickup tube and to prevent image inversion in the image pickup tube.
    Type: Grant
    Filed: March 23, 1981
    Date of Patent: September 20, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Saburo Ataka, Yoshinori Imamura, Yasuo Tanaka, Hirokazu Matsubara, Eiichi Maruyama
  • Patent number: 4380557
    Abstract: In preparing an image pickup device by using hydrogen-containing amorphous silicon for a photoconductive layer, a hydrogen-containing amorphous silicon layer is first formed and is then heat-treated at 100.degree. to 300.degree. C. The image pickup characteristics of the amorphous silicon layer are highly improved by this heat treatment. For example, the lag and dark current are reduced and the signal current-target voltage characteristic is improved. Especially excellent improving effects can be obtained when amorphous silicon characterized in that (1) the hydrogen content is 5 to 30 atomic %, (2) the optical forbidden band gap is 1.30 to 1.95 eV and (3) in the infrared absorption spectrum, the component of a wave number of 2000 cm.sup.-1 is observed larger than the component of a wave number of 2100 cm.sup.-1 is subjected to the above-mentioned heat treatment. The adhesion to the substrate is enhanced, and good image pickup characteristics can be obtained.
    Type: Grant
    Filed: July 28, 1981
    Date of Patent: April 19, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Sachio Ishioka, Yasuharu Shimomoto, Yoshinori Imamura, Saburo Ataka, Yasuo Tanaka, Hirokazu Matsubara, Yukio Takasaki, Eiichi Maruyama
  • Patent number: 4378417
    Abstract: In an electrophotographic member employing an amorphous silicon photoconductive layer, a part which is at least 10 nm thick inwardly of the amorphous silicon layer from the surface (or interface) of the amorphous silicon layer is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..cm. The electrophotographic member exhibits a satisfactory resolution and good dark-decay characteristics. Further, a region which has an optical forbidden band gap narrower than that of the amorphous silicon forming the surface (or interface) region is disposed within the amorphous silicon layer to a thickness of at least 10 nm, whereby the sensitivity of the electrophotographic member to longer wavelengths of light can be enhanced.
    Type: Grant
    Filed: April 15, 1981
    Date of Patent: March 29, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Maruyama, Sachio Ishioka, Yoshinori Imamura, Hirokazu Matsubara, Yasuharu Shimomoto, Shinkichi Horigome, Yoshio Taniguchi
  • Patent number: 4377628
    Abstract: Disclosed is an electrophotographic member having an amorphous-silicon photoconductive layer, wherein the distance between a portion in which light illuminating the photoconductor is absorbed therein until its intensity decreases to 1% of that at incidence and the interface of the photoconductor opposite to the light incidence side thereof is at most 5 .mu.m, whereby the residual potential of the photoconductive layer can be reduced.That part of the photoconductive layer constituting the electrophotographic member which is at least 10 nm thick inwardly of the photoconductive layer from the surface thereof to store charges is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..multidot.cm. Further, within such photoconductive layer, a region of amorphous silicon which has an optical forbidden band gap smaller than that of the amorphous silicon forming the surface part is disposed at a thickness of at least 10 nm.
    Type: Grant
    Filed: April 24, 1981
    Date of Patent: March 22, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Sachio Ishioka, Eiichi Maruyama, Yoshinori Imamura, Hirokazu Matsubara, Shinkichi Horigome
  • Patent number: 4365013
    Abstract: Disclosed is an electrophotographic member having at least a supporter and a photoconductor layer formed mainly of amorphous silicon, characterized in that the amorphous silicon contains at least 50 atomic-% of silicon and at least 1 atomic-% of hydrogen as an average within the layer, and that a part which is at least 10 nm thick from a surface or/and interface of the photoconductor layer toward the interior of the photoconductor layer has a hydrogen content in a range of at least 1 atomic-% to at most 40 atomic-% and an optical forbidden band gap in a range of at least 1.3 eV to at most 2.5 eV and also has the property that an intensity of at least one of peaks having centers at wave numbers of approximately 2,200 cm.sup.-1, approximately 1,140 cm.sup.-1, approximately 1,040 cm.sup.-1, approximately 650 cm.sup.-1, approximately 860 cm.sup.-1 and approximately 800 cm.sup.
    Type: Grant
    Filed: July 28, 1981
    Date of Patent: December 21, 1982
    Assignee: Hitachi, Ltd.
    Inventors: Sachio Ishioka, Eiichi Maruyama, Yoshinori Imamura, Hirokazu Matsubara, Shinkichi Horigome
  • Patent number: RE33094
    Abstract: In an electrophotographic member employing an amorphous silicon photoconductive layer, a part which is at least 10 nm thick inwardly of the amorphous silicon layer from the surface (or interface) of the amorphous silicon layer is made of amorphous silicon which has an optical forbidden band gap of at least 1.6 eV and a resistivity of at least 10.sup.10 .OMEGA..cm. The electrophotographic member exhibits a satisfactory resolution and good dark-decay characteristics. Further, a region which has an optical forbidden band gap narrower than that of the amorphous silicon forming the surface (or interface) region is disposed within the amorphous silicon layer to a thickness of at least 10 nm, whereby the sensitivity of the electrophotographic member to longer wavelengths of light can be enhanced.
    Type: Grant
    Filed: September 11, 1986
    Date of Patent: October 17, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Eiichi Maruyama, Sachio Ishioka, Yoshinori Imamura, Hirokazu Matsubara, Yasuharu Shimomoto, Shinkichi Horigome, Yoshio Taniguchi