Patents by Inventor Kazutaka Takeda

Kazutaka Takeda 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: 20130234167
    Abstract: Disclosed is a light-emitting element including a semiconductor substrate, an island structure formed on the semiconductor substrate and including at least a current confining layer and p-type and n-type semiconductor layers, a light-emitting thyristor formed in the island structure and having a pnpn structure, and a shift thyristor formed in the island structure and having a pnpn structure, wherein a groove portion having a depth such that the groove portion reaches at least the current confining layer is formed between a formation region of the shift thyristor of the island structure and a formation region of the light-emitting thyristor, and an oxidized region that is selectively oxidized from a side surface of the island structure and a side surface of the groove portion is formed in the current confining layer.
    Type: Application
    Filed: July 31, 2012
    Publication date: September 12, 2013
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Taku KINOSHITA, Kazutaka TAKEDA, Takashi KONDO, Hideo NAKAYAMA
  • Publication number: 20130234168
    Abstract: Provided is a light-emitting element including a semiconductor substrate, an island structure formed on the semiconductor substrate and including at least a current confining layer and p-type and n-type semiconductor layers, a light-emitting thyristor formed in the island structure and having a pnpn structure, and a shift thyristor formed in the island structure and having a pnpn structure, wherein the island structure includes a first side surface having a first depth such that the first side surface does not reach the current confining layer in a formation region of the shift thyristor and a second side surface having a second depth such that the second side surface reaches at least the current confining layer in a formation region of the light-emitting thyristor, and an oxidized region selectively oxidized from the second side surface is formed in the current confining layer in the formation region of the light-emitting thyristor.
    Type: Application
    Filed: August 1, 2012
    Publication date: September 12, 2013
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Taku KINOSHITA, Michiaki MURATA, Takashi KONDO, Kazutaka TAKEDA, Hideo NAKAYAMA
  • Publication number: 20130188993
    Abstract: A surface-emitting semiconductor laser includes a substrate, a first n-type semiconductor multi-layer reflecting mirror formed on the substrate including a pair of a high refractive index layer with a relatively high refractive index and a low refractive index layer with a low refractive index which are laminated, an n-type semiconductor layer formed on the first semiconductor multi-layer reflecting mirror, having an optical film thickness greater than an oscillation wavelength, and including Al and Ga, an active region formed on the semiconductor layer, and a second p-type semiconductor multi-layer reflecting mirror formed on the active region and including a pair of a high refractive index layer with a relatively high refractive index and a low refractive index layer with a low refractive index which are laminated, wherein an n-type impurity dopant injected into the semiconductor layer is a group VI material or Sn.
    Type: Application
    Filed: July 18, 2012
    Publication date: July 25, 2013
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Kazutaka TAKEDA, Hideo NAKAYAMA
  • Patent number: 8465993
    Abstract: A vertical cavity surface emitting laser that includes: a substrate; a first semiconductor multilayer reflector; an active region; a second semiconductor multilayer reflector; a columnar structure formed from the second semiconductor multilayer reflector to the first semiconductor multilayer reflector; a current narrowing layer formed inside of the columnar structure and having a conductive region surrounded by an oxidization region; a first electrode formed at a top of the columnar structure, electrically connected to the second semiconductor multilayer reflector and defining a beam window; a first insulating film comprised of a material with a first refractive index and formed on the first electrode to cover the beam window; and a second insulating film comprised of a material with a second refractive index and formed on the first insulating film, of which a radius is smaller than a radius of the conductive region.
    Type: Grant
    Filed: October 12, 2012
    Date of Patent: June 18, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazutaka Takeda, Masahiro Yoshikawa, Kazuyuki Matsushita
  • Publication number: 20130083304
    Abstract: A vertical cavity surface emitting laser includes a first semiconductor multilayer reflector, a resonator, and a second semiconductor multilayer reflector. The first semiconductor multilayer reflector is formed on a substrate and is configured by stacking a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively low refractive index. The resonator includes an active layer formed on the first semiconductor multilayer reflector. The second semiconductor multilayer reflector is configured by stacking the high refractive index layer and the low refractive index layer. The resonator includes a pair of spacer layers disposed vertically on the active layer and a resonator extension area formed at one side of the pair of spacer layers. The resonator extension area contains a material in which an energy level with a crystal defect is higher than a general energy level without the crystal defect.
    Type: Application
    Filed: April 26, 2012
    Publication date: April 4, 2013
    Applicants: TOKYO INSTITUTE OF TECHNOLOGY, FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Hideo NAKAYAMA, Kazutaka TAKEDA, Fumio KOYAMA
  • Publication number: 20130049027
    Abstract: A light emitting element includes a semiconductor substrate, and an island structure formed on the semiconductor substrate. The island structure includes a light-emitting-unit thyristor and a current confinement structure. The light-emitting-unit thyristor includes stacked semiconductor layers having a pnpn structure. The current confinement structure includes a high-resistance region and a conductive region, and confines carriers in the conductive region.
    Type: Application
    Filed: February 23, 2012
    Publication date: February 28, 2013
    Applicant: FUJI XEROX CO. LTD.
    Inventors: Taku KINOSHITA, Takashi KONDO, Kazutaka TAKEDA, Hideo NAKAYAMA
  • Publication number: 20130034922
    Abstract: A vertical cavity surface emitting laser that includes: a substrate; a first semiconductor multilayer reflector; an active region; a second semiconductor multilayer reflector; a columnar structure formed from the second semiconductor multilayer reflector to the first semiconductor multilayer reflector; a current narrowing layer formed inside of the columnar structure and having a conductive region surrounded by an oxidization region; a first electrode formed at a top of the columnar structure, electrically connected to the second semiconductor multilayer reflector and defining a beam window; a first insulating film comprised of a material with a first refractive index and formed on the first electrode to cover the beam window; and a second insulating film comprised of a material with a second refractive index and formed on the first insulating film, of which a radius is smaller than a radius of the conductive region.
    Type: Application
    Filed: October 12, 2012
    Publication date: February 7, 2013
    Inventors: Kazutaka Takeda, Masahiro Yoshikawa, Kazuyuki Matsushita
  • Patent number: 8368972
    Abstract: A surface-emitting semiconductor laser includes a substrate, a first semiconductor multi-layered reflector of a first conductivity type, an active region, a second semiconductor multi-layered reflector of a second conductivity type, a columnar structure, a current-confining layer including a conductive area surrounded with an oxidized area, a first electrode defining a light-emitting window, a first dielectric film covering the light-emitting window, and a second dielectric film formed on the first dielectric film. The second dielectric film has an asymmetrical shape having a long axis and a short axis, the second dielectric film is located at a position overlapping with the conductive area, the second refractive index n2 is greater than the first refractive index n1, the thickness of the first dielectric film is an odd multiple of ?/4·n1 (?: oscillation wavelength), and the thickness of the second dielectric film is an odd multiple of ?/4·n2.
    Type: Grant
    Filed: July 25, 2011
    Date of Patent: February 5, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazutaka Takeda, Hideo Nakayama
  • Publication number: 20130020592
    Abstract: Provided is a light-emitting device including a semiconductor substrate of a first conductivity type, a semiconductor multilayer reflection mirror of the first conductivity type, formed on the semiconductor substrate, a first semiconductor layer of the first conductivity type, formed on the semiconductor multilayer reflection mirror, a second semiconductor layer of a second conductivity type, formed on the first semiconductor layer, a third semiconductor layer of the first conductivity type, formed on the second semiconductor layer, a fourth semiconductor layer of the second conductivity type, formed on the third semiconductor layer, a first electrode formed on a rear surface of the semiconductor substrate, and a second electrode formed on the fourth semiconductor layer, wherein the semiconductor multilayer reflection mirror includes a first selectively oxidized region and a first conductive region adjacent to the first oxidized region, and the first conductive region electrically connects the semiconductor s
    Type: Application
    Filed: May 21, 2012
    Publication date: January 24, 2013
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Taku KINOSHITA, Kazutaka TAKEDA
  • Patent number: 8311073
    Abstract: A semiconductor laser that includes: a substrate; a first semiconductor multilayer reflector of a first conductive type formed on the substrate; an active region formed on the first semiconductor multilayer reflector; a second semiconductor multilayer reflector of a second conductive type formed on the active region; and an intermediate semiconductor layer of a first conductive type or a second conductive type formed under the first semiconductor multilayer reflector or above the second semiconductor multilayer reflector.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: November 13, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazutaka Takeda, Takashi Kondo, Hideaki Ozawa
  • Patent number: 8295318
    Abstract: A vertical cavity surface emitting laser including a substrate, a first semiconductor multilayer film reflector formed on the substrate, an active region formed on the first semiconductor multilayer film reflector, a second semiconductor multilayer film reflector formed on the active region, an electrode formed on the second semiconductor multilayer film reflector, a light absorption layer, and a light transmission layer. In the electrode, a light emitting aperture is formed. The light absorption layer is formed in a peripheral region of the light emitting aperture, and absorbs emitted light. The light transmission layer is composed of a material which the emitted light can pass through, and formed in a central region of the light emitting aperture. Thicknesses of the light absorption layer and the light transmission layer are selected so that phases of light from the light absorption layer and from the light transmission layer are adjusted.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: October 23, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazuyuki Matsushita, Takashi Kondo, Kazutaka Takeda
  • Patent number: 8270448
    Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector of a first conduction type that is formed on the substrate and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers; a cavity region that is formed on the first semiconductor multilayer reflector and includes an active region; and a second semiconductor multilayer reflector of a second conduction type that is formed on the cavity region and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers. A cavity length of a cavity that includes the cavity region and the active region between the first semiconductor multilayer reflector and the second semiconductor multilayer reflector is greater than an oscillation wavelength.
    Type: Grant
    Filed: July 26, 2010
    Date of Patent: September 18, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takashi Kondo, Kazutaka Takeda
  • Publication number: 20120170084
    Abstract: A surface-emitting semiconductor laser includes a substrate, a first semiconductor multi-layered reflector of a first conductivity type, an active region, a second semiconductor multi-layered reflector of a second conductivity type, a columnar structure, a current-confining layer including a conductive area surrounded with an oxidized area, a first electrode defining a light-emitting window, a first dielectric film covering the light-emitting window, and a second dielectric film formed on the first dielectric film. The second dielectric film has an asymmetrical shape having a long axis and a short axis, the second dielectric film is located at a position overlapping with the conductive area, the second refractive index n2 is greater than the first refractive index n1, the thickness of the first dielectric film is an odd multiple of ?/4·n1 (?: oscillation wavelength), and the thickness of the second dielectric film is an odd multiple of ?/4·n2.
    Type: Application
    Filed: July 25, 2011
    Publication date: July 5, 2012
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka TAKEDA, Hideo NAKAYAMA
  • Publication number: 20110317540
    Abstract: A vertical cavity surface emitting laser including a substrate, a first semiconductor multilayer film reflector formed on the substrate, an active region formed on the first semiconductor multilayer film reflector, a second semiconductor multilayer film reflector formed on the active region, an electrode formed on the second semiconductor multilayer film reflector, a light absorption layer, and a light transmission layer. In the electrode, a light emitting aperture is formed. The light absorption layer is formed in a peripheral region of the light emitting aperture, and absorbs emitted light. The light transmission layer is composed of a material which the emitted light can pass through, and formed in a central region of the light emitting aperture. Thicknesses of the light absorption layer and the light transmission layer are selected so that phases of light from the light absorption layer and from the light transmission layer are adjusted.
    Type: Application
    Filed: October 18, 2010
    Publication date: December 29, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazuyuki MATSUSHITA, Takashi KONDO, Kazutaka TAKEDA
  • Publication number: 20110318020
    Abstract: A vertical cavity surface emitting laser includes a substrate, a first semiconductor multilayer film reflector formed on the substrate, an active region formed on the first semiconductor multilayer film reflector, a second semiconductor multilayer film reflector formed on the active region, an electrode which is formed on the second semiconductor multilayer film reflector and in which a light emitting aperture is formed, a first substance that is composed of a material and that is formed in the light emitting aperture, and a second substance that is composed of a dielectric and that is formed on the first substance to cover one portion of the first substance. Light having an emission wavelength can pass through the material and dielectric. A reflectivity of a portion covered with the second substance is higher than a reflectivity of a portion that is not covered with the second substance.
    Type: Application
    Filed: November 5, 2010
    Publication date: December 29, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Kazutaka TAKEDA, Kazuyuki MATSUSHITA
  • Publication number: 20110222569
    Abstract: A semiconductor laser that includes: a substrate; a first semiconductor multilayer reflector of a first conductive type formed on the substrate; an active region formed on the first semiconductor multilayer reflector; a second semiconductor multilayer reflector of a second conductive type formed on the active region; and an intermediate semiconductor layer of a first conductive type or a second conductive type formed under the first semiconductor multilayer reflector or above the second semiconductor multilayer reflector.
    Type: Application
    Filed: September 10, 2010
    Publication date: September 15, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka TAKEDA, Takashi KONDO, Hideaki OZAWA
  • Publication number: 20110182316
    Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector of a first conduction type that is formed on the substrate and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers; a cavity region that is formed on the first semiconductor multilayer reflector and includes an active region; and a second semiconductor multilayer reflector of a second conduction type that is formed on the cavity region and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers. A cavity length of a cavity that includes the cavity region and the active region between the first semiconductor multilayer reflector and the second semiconductor multilayer reflector is greater than an oscillation wavelength.
    Type: Application
    Filed: July 26, 2010
    Publication date: July 28, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takashi KONDO, Kazutaka Takeda
  • Publication number: 20110150500
    Abstract: A vertical cavity surface emitting laser that includes: a substrate; a first semiconductor multilayer reflector; an active region; a second semiconductor multilayer reflector; a columnar structure formed on the substrate; a current narrowing layer that is formed inside of the columnar structure, and has a conductive region surrounded by an oxidization region selectively oxidized; a first electrode that is formed at a top of the columnar structure, and defines a beam window; a first insulating film that covers the beam window; and a second insulating film of which a second refractive index is larger than the first refractive index. A reflection ratio in a second region where the second insulating film is formed is lower than a reflection ratio in a first region where only the first insulating film is formed.
    Type: Application
    Filed: May 7, 2010
    Publication date: June 23, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazuyuki Matsushita, Hideo Nakayama, Masahiro Yoshikawa, Kazutaka Takeda
  • Publication number: 20110135318
    Abstract: A vertical cavity surface emitting laser that includes: a substrate; a first semiconductor multilayer reflector; an active region; a second semiconductor multilayer reflector; a columnar structure formed from the second semiconductor multilayer reflector to the first semiconductor multilayer reflector; a current narrowing layer formed inside of the columnar structure and having a conductive region surrounded by an oxidization region; a first electrode formed at a top of the columnar structure, electrically connected to the second semiconductor multilayer reflector and defining a beam window; a first insulating film comprised of a material with a first refractive index and formed on the first electrode to cover the beam window; and a second insulating film comprised of a material with a second refractive index and formed on the first insulating film, of which a radius is smaller than a radius of the conductive region.
    Type: Application
    Filed: May 17, 2010
    Publication date: June 9, 2011
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Kazutaka Takeda, Masahiro Yoshikawa, Kazuyuki Matsushita