Patents by Inventor Minoru Niigaki

Minoru Niigaki 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: 9368661
    Abstract: A photodetector 1A comprises a multilayer structure 3 having a first layer 4 constituted by first metal or first semiconductor, a semiconductor structure layer 5 mounted on the first layer 4 and adapted to excite an electron by plasmon resonance, and a second layer 6 mounted on the semiconductor structure layer 5 and constituted by second metal or second semiconductor.
    Type: Grant
    Filed: May 22, 2013
    Date of Patent: June 14, 2016
    Assignee: HAMAMATSU PHOTONICS K.K.
    Inventors: Kazutoshi Nakajima, Toru Hirohata, Minoru Niigaki, Wataru Akahori, Kazuue Fujita
  • Publication number: 20150097156
    Abstract: A photodetector 1A comprises an optical element 10, having a structure including first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to a predetermined direction, for generating an electric field component in the predetermined direction when light is incident thereon along the predetermined direction; and a semiconductor multilayer body 4 having a quantum cascade structure, arranged on the other side opposite from one side in the predetermined direction with respect to the optical element, for producing a current according to the electric field component in the predetermined direction generated by the optical element 10; while the quantum cascade structure includes an active region 4b for exciting an electron and an injector region 4c for transporting the electron, the active region 4b being formed on the outermost surface on the one side of the injector region 4c in the quantum cascade structure.
    Type: Application
    Filed: May 10, 2013
    Publication date: April 9, 2015
    Inventors: Kazutoshi Nakajima, Minoru Niigaki, Toru Hirohata, Hiroyuki Yamashita, Wataru Akahori, Kazuue Fujita, Kazunori Tanaka
  • Publication number: 20150053922
    Abstract: A photodetector 1A comprises an optical element 10, having a structure including first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to a predetermined direction, for generating an electric field component in the predetermined direction when light is incident thereon along the predetermined direction; arid a semiconductor multilayer body 4 having a quantum cascade structure, arranged on the other side opposite from one side in the predetermined direction with respect to the optical element, for producing a current according to the electric field component in the predetermined direction generated by the optical element 10; while the quantum cascade structure includes an active region 4b having a first upper quantum level and a second upper quantum level lower than the first upper quantum level, and an injector region 4c for transporting an electron excited by the active region 4b.
    Type: Application
    Filed: May 10, 2013
    Publication date: February 26, 2015
    Inventors: Kazutoshi Nakajima, Masamichi Yamanishi, Kazuue Fujita, Minoru Niigaki, Toru Hirohata, Hiroyuki Yamashita, Wataru Akahori
  • Publication number: 20140319637
    Abstract: A photodetector 1A comprises an optical element 10A for generating an electric field component in a predetermined direction when light is incident thereon along the predetermined direction, the optical element 10A having a structure including first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to the predetermined direction; and a semiconductor layer 40, arranged on the other side opposite from one side in the predetermined direction with respect to the optical element 10A, having a semiconductor multilayer body 42 for generating a current according to the electric field component; each end part on the other side of the second regions being located closer to the other side than is each end part on the other side of the first regions; each first region being made of a dielectric body having a refractive index greater than that of each second region.
    Type: Application
    Filed: April 23, 2014
    Publication date: October 30, 2014
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Kazutoshi NAKAJIMA, Minoru NIIGAKI, Toru HIROHATA, Hiroyuki YAMASHITA, Wataru AKAHORI
  • Publication number: 20130320470
    Abstract: A photodetector 1A comprises a multilayer structure 3 having a first layer 4 constituted by first metal or first semiconductor, a semiconductor structure layer 5 mounted on the first layer 4 and adapted to excite an electron by plasmon resonance, and a second layer 6 mounted on the semiconductor structure layer 5 and constituted by second metal or second semiconductor.
    Type: Application
    Filed: May 22, 2013
    Publication date: December 5, 2013
    Inventors: Kazutoshi NAKAJIMA, Toru HIROHATA, Minoru NIIGAKI, Wataru AKAHORI, Kazuue FUJITA
  • Patent number: 8482197
    Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: July 9, 2013
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, Toru Hirohata, Hiroyasu Fujiwara, Akira Higuchi
  • Patent number: 8446094
    Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: May 21, 2013
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, Toru Hirohata, Hiroyasu Fujiwara, Akira Higuchi
  • Patent number: 8164069
    Abstract: A light-emitting body of rapid speed of response and high light emission intensity, and an electron beam detector, scanning electron microscope and mass spectroscope using this are provided. In the light-emitting body 10 according to the present invention, when fluorescence is emitted by a nitride semiconductor layer 14 formed on one face 12a of a substrate 12 in response to incidence of electrons, at least some of this fluorescence is transmitted through this substrate 12, whereby that fluorescence is emitted from the other face 12b of the substrate. The response speed of this fluorescence is not more than ?sec order. Also, the intensity of emission of this fluorescence is almost identical to that of a conventional P47 phosphor. Specifically, with this light-emitting body 10, a response speed and light emission intensity are obtained that are fully satisfactory for application to a scanning electron microscope or mass spectroscope.
    Type: Grant
    Filed: January 10, 2011
    Date of Patent: April 24, 2012
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Shoichi Uchiyama, Yasufumi Takagi, Minoru Niigaki, Minoru Kondo, Itaru Mizuno
  • Publication number: 20110101219
    Abstract: A light-emitting body of rapid speed of response and high light emission intensity, and an electron beam detector, scanning electron microscope and mass spectroscope using this are provided. In the light-emitting body 10 according to the present invention, when fluorescence is emitted by a nitride semiconductor layer 14 formed on one face 12a of a substrate 12 in response to incidence of electrons, at least some of this fluorescence is transmitted through this substrate 12, whereby that fluorescence is emitted from the other face 12b of the substrate. The response speed of this fluorescence is not more than ?sec order. Also, the intensity of emission of this fluorescence is almost identical to that of a conventional P47 phosphor. Specifically, with this light-emitting body 10, a response speed and light emission intensity are obtained that are fully satisfactory for application to a scanning electron microscope or mass spectroscope.
    Type: Application
    Filed: January 10, 2011
    Publication date: May 5, 2011
    Inventors: Shoichi UCHIYAMA, Yasufumi TAKAGI, Minoru NIIGAKI, Minoru KONDO, Itaru MIZUNO
  • Patent number: 7910895
    Abstract: A light-emitting body of rapid speed of response and high light emission intensity, and an electron beam detector, scanning electron microscope and mass spectroscope using this are provided. In the light-emitting body 10 according to the present invention, when fluorescence is emitted by a nitride semiconductor layer 14 formed on one face 12a of a substrate 12 in response to incidence of electrons, at least some of this fluorescence is transmitted through this substrate 12, whereby that fluorescence is emitted from the other face 12b of the substrate. The response speed of this fluorescence is not more than ?sec order. Also, the intensity of emission of this fluorescence is almost identical to that of a conventional P47 phosphor. Specifically, with this light-emitting body 10, a response speed and light emission intensity are obtained that are fully satisfactory for application to a scanning electron microscope or mass spectroscope.
    Type: Grant
    Filed: April 7, 2005
    Date of Patent: March 22, 2011
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Shoichi Uchiyama, Yasufumi Takagi, Minoru Niigaki, Minoru Kondo, Itaru Mizuno
  • Patent number: 7816866
    Abstract: A semiconductor photocathode 1 includes: a transparent substrate 11; a first electrode 13, formed on the transparent substrate 11 and enabling passage of light that has been transmitted through the transparent substrate 11; a window layer 14, formed on the first electrode 13 and formed of a semiconductor material with a thickness of no less than 10 nm and no more than 200 nm; a light absorbing layer 15, formed on the window layer 14, formed of a semiconductor material that is lattice matched to the window layer 14, is narrower in energy band gap than the window layer 14, and in which photoelectrons are excited in response to the incidence of light; an electron emission layer 16, formed on the light absorbing layer 15, formed of a semiconductor material that is lattice matched to the light absorbing layer 15, and emitting the photoelectrons excited in the light absorbing layer 15 to the exterior from a surface; and a second electrode 18, formed on the electron emission layer.
    Type: Grant
    Filed: October 25, 2006
    Date of Patent: October 19, 2010
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Kazutoshi Nakajima, Minoru Niigaki, Tomoko Mochizuki, Toru Hirohata
  • Patent number: 7795608
    Abstract: When to-be-detected light is made incident from a support substrate 2 side of a photocathode E1, a light absorbing layer 3 absorbs this to-be-detected light and produces photoelectrons. However, depending on the thickness and the like of the light absorbing layer 3, the to-be-detected light can be transmitted through the light absorbing layer 3 without being sufficiently absorbed by the light absorbing layer 3. The to-be-detected light transmitted through the light absorbing layer 3 reaches an electron emitting layer 4. A part of the to-be-detected light that has reached the electron emitting layer 4 proceeds toward a through-hole 5a of a contact layer 5. Since the length d1 of a diagonal line of the through-hole 5a is shorter than the wavelength of the to-be-detected light, the to-be-detected light can be suppressed from passing through the through-hole 5a and being emitted to the exterior.
    Type: Grant
    Filed: July 23, 2008
    Date of Patent: September 14, 2010
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Toru Hirohata, Minoru Niigaki
  • Publication number: 20100148667
    Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.
    Type: Application
    Filed: February 25, 2010
    Publication date: June 17, 2010
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Minoru NIIGAKI, Toru Hirohata, Hiroyasu Fujiwara, Akira Higuchi
  • Patent number: 7652425
    Abstract: A transmission type photocathode includes a light absorption layer 1 formed of diamond or a material containing diamond as a main component, a supporting frame 21 for reinforcing the mechanical strength of the light absorption layer 1, a first electrode 31 provided at the plane of incidence of the light absorption layer 1, and a second electrode 32 provided at the plane of emission of the light absorption layer 1. A voltage is applied between the plane of incidence and plane of emission of the light absorption layer 1 to form an electric field in the light absorption layer 1. When light to be detected is made incident and photoelectrons occur in the light absorption layer 1, the photoelectrons are accelerated to the plane of emission by the electric field formed in the light absorption layer 1, and emitted to the outside of the transmission type photocathode.
    Type: Grant
    Filed: February 24, 2003
    Date of Patent: January 26, 2010
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, Shoichi Uchiyama, Hirofumi Kan
  • Publication number: 20090273281
    Abstract: The photocathode of the present invention is provided with a supporting substrate composed of a single-crystal compound semiconductor, a light absorbing layer which is formed on the supporting substrate and smaller in an energy band gap than the supporting substrate to absorb incident light transmitted through the supporting substrate, thereby generating photoelectrons, and a surface layer which is formed on the light absorbing layer to lower a work function of the light absorbing layer, in which the supporting substrate comprises Al(1?x)GaxN (0?X<1) and the light absorbing layer comprises a compound semiconductor composed of at least one material selected from the group consisting of Al, Ga and In, and N.
    Type: Application
    Filed: April 30, 2009
    Publication date: November 5, 2009
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Minoru Niigaki, Toru Hirohata, Harumasa Yoshida, Hirofumi Kan
  • Patent number: 7586968
    Abstract: An alkali-encapsulated cell internally having an alkali metal vapor G encapsulated is provided with first and second heaters 11, 12. The alkali-encapsulated cell 10 has first and second end faces 10a, 10b opposed to each other, and a side face 10c connecting the two end faces 10a, 10b. Each of the first and second heaters 11, 12 has a covering portion 11B, 12B and an extending portion 11C, 12C. Some portions of the alkali-encapsulated cell 10 are inserted in the covering portions 11B, 12B. On the other hand, the extending portions 11C, 12C extend in directions away from the alkali-encapsulated cell 10. The first and second heaters 11, 12 are separated from each other with a distance d0 between them in an opposing direction of the first and second end faces 10a, 10b.
    Type: Grant
    Filed: July 26, 2007
    Date of Patent: September 8, 2009
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, You Wang, Yujin Zheng, Hirofumi Kan
  • Patent number: 7557336
    Abstract: When light is made incident into antenna layers 11a, 11b, and 11c of a photodetector 1, specific wavelength components of light contained in the incident light combine with surface plasmons of the antenna layers 11a, 11b, and 11c, and surface plasmon resonance occurs. Thereby, near-field lights are outputted from through-holes 13 of the antenna layers 11a, 11b, and 11c. The near-field light outputted from each through-hole 13 reaches a light absorbing layer 4 via light receiving surfaces 4a, 4b, and 4c. The light absorbing layer 4 generates a charge of an amount according to the amount of received light. Since cycle intervals ?a, ?b, and ?c of convex portions 12 in the antenna layers 11a, 11b, and 11c are different from each other, the wavelength component of light that combines with a surface plasmon differs in each of the antenna layers 11a, 11b, and 11c. Consequently, a plurality of wavelength components of light can be detected.
    Type: Grant
    Filed: May 9, 2007
    Date of Patent: July 7, 2009
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Minoru Niigaki, Toru Hirohata, Hiroyasu Fujiwara, Akira Higuchi
  • Publication number: 20090032797
    Abstract: When to-be-detected light is made incident from a support substrate 2 side of a photocathode E1, a light absorbing layer 3 absorbs this to-be-detected light and produces photoelectrons. However, depending on the thickness and the like of the light absorbing layer 3, the to-be-detected light can be transmitted through the light absorbing layer 3 without being sufficiently absorbed by the light absorbing layer 3. The to-be-detected light transmitted through the light absorbing layer 3 reaches an electron emitting layer 4. A part of the to-be-detected light that has reached the electron emitting layer 4 proceeds toward a through-hole 5a of a contact layer 5. Since the length d1 of a diagonal line of the through-hole 5a is shorter than the wavelength of the to-be-detected light, the to-be-detected light can be suppressed from passing through the through-hole 5a and being emitted to the exterior.
    Type: Application
    Filed: July 23, 2008
    Publication date: February 5, 2009
    Applicant: HAMAMATSU PHOTONICS K.K.
    Inventors: Toru Hirohata, Minoru Niigaki
  • Publication number: 20080121928
    Abstract: A semiconductor photocathode has first and second III-V compound semiconductor layers doped with a p-type impurity and joined to each other to make a heterojunction. The second III-V compound semiconductor layer functions as a light absorbing layer, an energy gap of the second III-V compound semiconductor layer is smaller than that of the first III-V compound semiconductor layer, and Be or C is used as the p-type dopant in each semiconductor layer. At this time, the second III-V compound semiconductor layer may be deposited on the first III-V compound semiconductor layer. The first III-V compound semiconductor layer and the second III-V compound semiconductor layer may contain at least one from each group of (In, Ga, Al) and (As, P, N).
    Type: Application
    Filed: November 28, 2007
    Publication date: May 29, 2008
    Inventors: Minoru Niigaki, Kazutoshi Nakajima, Toru Hirohata, Hirofumi Kan
  • Publication number: 20080121909
    Abstract: A semiconductor device has first and second III-V compound semiconductor layers one of which functions as a photosensitive layer or as a light emitting layer, which are doped with a p-type impurity in a low concentration, and which are joined to each other to make a heterojunction. An energy gap of the second III-V compound semiconductor layer is smaller than that of the first III-V compound semiconductor layer and the p-type dopant in each semiconductor layer is Be or C. At this time, the second III-V compound semiconductor layer may be deposited on the first III-V compound semiconductor layer. The first III-V compound semiconductor layer and the second III-V compound semiconductor layer may contain at least one from each group of (In, Ga, Al) and (As, P, N).
    Type: Application
    Filed: November 28, 2007
    Publication date: May 29, 2008
    Inventors: Minoru Niigaki, Toru Hirohata, Kazutoshi Nakajima, Hirofumi Kan