Patents by Inventor Yoshiaki Hasegawa

Yoshiaki Hasegawa 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: 7738525
    Abstract: A semiconductor laser (101) includes a first cladding layer (103), an active layer (105) and a second cladding layer (108). A window region (115) including fluorine, that is, an impurity element with higher electronegativity than nitrogen, is formed in the vicinity of a front end face (113) and a rear end face (114) of a laser resonator. The window region (115) is formed by exposing the front end face (113) and the rear end face (114) to carbon fluoride (CF4) plasma. The effective band gap of a portion of the active layer (105) disposed in the window region (115) is larger than the effective band gap of another portion of the active layer, and hence, it functions as an end face window structure for suppressing COD.
    Type: Grant
    Filed: July 9, 2007
    Date of Patent: June 15, 2010
    Assignee: Panasonic Corporation
    Inventors: Daisuke Ueda, Masaaki Yuri, Yoshiaki Hasegawa, Kenichi Matsuda
  • Publication number: 20100144339
    Abstract: The normality verification and radio characteristics test of a radio communication system are executed. RF-SWs (radio-frequency coaxial switches) change-over the paths of signals which are transmitted to and received from an access terminal function portion included in an access point. RF-SWs connect the access terminal function portion 122 with a desired one of radio analog portions. A test function controller controls the changeover operations of the RF-SWs in accordance with information designated by a maintenance apparatus (OMC). An access point controller controls in accordance with received test sort information, one or more of (1) an antenna failure test, (2) a receiver failure test, and (3) a transmitter failure.
    Type: Application
    Filed: February 16, 2010
    Publication date: June 10, 2010
    Inventors: Yoshiaki HASEGAWA, Shinya OOTA, Yoshihiro KANOMATA, Arata NAKAGOSHI
  • Patent number: 7704860
    Abstract: A nitride-based semiconductor device according to the present invention includes a semiconductor multilayer structure supported on a substrate structure 101 with electrical conductivity. The principal surface of the substrate structure 101 has at least one vertical growth region, which functions as a seed crystal for growing a nitride-based semiconductor vertically, and a plurality of lateral growth regions for allowing the nitride-based semiconductor that has grown on the vertical growth region to grow laterally. The sum ?X of the respective sizes of the vertical growth regions as measured in the direction pointed by the arrow A and the sum ?Y of the respective sizes of the lateral growth regions as measured in the same direction satisfy the inequality ?X/?Y>1.0.
    Type: Grant
    Filed: November 15, 2005
    Date of Patent: April 27, 2010
    Assignee: Panasonic Corporation
    Inventors: Toshitaka Shimamoto, Yasutoshi Kawaguchi, Yoshiaki Hasegawa, Akihiko Ishibashi, Isao Kidoguchi, Toshiya Yokogawa
  • Patent number: 7653099
    Abstract: A semiconductor laser device according to the present invention includes: a semiconductor laser chip 1 for emitting laser light; a stem 3, 4 for supporting the semiconductor laser chip; a plurality of terminal electrodes, inserted in throughholes provided in the stem 3, 4, for supplying power to the semiconductor laser chip; and a cap 5 having an optical window 6 which transmits laser light and being affixed to the stem 3, 4 so as to cover the semiconductor laser chip 1. Between the stem 3, 4 and the terminal electrodes 7, this device includes insulation glass 8, which does not release silicon fluoride gas when heated to a temperature of no less than 700° C. and no more than 850° C.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: January 26, 2010
    Assignee: Panasonic Corporation
    Inventors: Yoshiaki Hasegawa, Toshiya Yokogawa, Hiroyoshi Yajima
  • Publication number: 20100014550
    Abstract: A nitride semiconductor laser device includes a multilayer structure including a plurality of nitride semiconductor layers including a light emitting layer, the multilayer structure having cavity facets facing each other, and a plurality of protective films made of a dielectric material provided on one of the cavity facets. The protective films include a first protective film, a second protective film and a third protective film. The first protective film contacts the cavity facet and is made of aluminum nitride. The second protective film is provided on a surface opposite to the cavity facet of the first protective film and is made of a material different from that of the first protective film. The third protective film is provided on a surface opposite to the first protective film of the second protective film and is made of the same material as that of the first protective film.
    Type: Application
    Filed: May 22, 2009
    Publication date: January 21, 2010
    Inventors: Yoshiaki HASEGAWA, Atsunori MOCHIDA
  • Publication number: 20090294797
    Abstract: A semiconductor light-emitting device according to the present invention includes: a GaN substrate 1 containing an n-type impurity and being made of silicon carbide or a nitride semiconductor; a multilayer structure 10 provided on a main surface of the GaN substrate 1; a p-electrode 17 formed on the multilayer structure 10; a first n-electrode 18 substantially covering the entire rear surface of the GaN substrate 1; and a second n-electrode 20 provided on the first n-electrode 18 so as to expose at least a portion of the periphery of the first n-electrode 18.
    Type: Application
    Filed: July 13, 2007
    Publication date: December 3, 2009
    Inventors: Naomi Anzue, Gaku Sugahara, Yoshiaki Hasegawa, Akihiko Ishibashi, Toshiya Yokogawa
  • Patent number: 7622749
    Abstract: A method for fabricating a semiconductor light-emitting element according to the present invention includes the steps of (A) providing a striped masking layer on a first Group III-V compound semiconductor, (B) selectively growing a second Group III-V compound semiconductor over the entire surface of the first Group III-V compound semiconductor except a portion covered with the masking layer, thereby forming a current confining layer that has a striped opening defined by the masking layer, (C) selectively removing the masking layer, and (D) growing a third Group III-V compound semiconductor to cover the surface of the first Group III-V compound semiconductor, which is exposed through the striped opening, and the surface of the current confining layer.
    Type: Grant
    Filed: January 11, 2008
    Date of Patent: November 24, 2009
    Assignee: Panasonic Corporation
    Inventors: Yoshiaki Hasegawa, Toshiya Yokogawa, Atsushi Yamada
  • Patent number: 7606276
    Abstract: A nitride semiconductor device 100 according to the present invention includes: an n-GaN substrate 1; a semiconductor multilayer structure, which has been formed on the principal surface of the n-GaN substrate 1 and which includes a p-type region and an n-type region; a p-electrode 32, which makes contact with a portion of the p-type region included in the semiconductor multilayer structure; and an n-electrode 34, which is arranged on the bottom surface of the substrate 1. The bottom surface of the substrate 1 includes a roughened region 40a and a flattened region 40b. And the n-electrode 34 covers the roughened region 40a at least partially.
    Type: Grant
    Filed: May 12, 2006
    Date of Patent: October 20, 2009
    Assignee: Panasonic Corporation
    Inventors: Yoshiaki Hasegawa, Akihiko Ishibashi, Toshiya Yokogawa
  • Publication number: 20090236630
    Abstract: A nitride semiconductor light emitting device includes a nitride semiconductor multilayer film. The nitride semiconductor multilayer film is formed on a substrate and made of nitride semiconductor crystals, and includes a light emitting layer. In the nitride semiconductor multilayer film, facets of a cavity are formed, and a protective film made of aluminum nitride crystals is formed on at least one of the facets. The protective film has a crystal plane whose crystal axes form an angle of 90 degrees with crystal axes of a crystal plane of the nitride semiconductor crystals constituting the facet of the cavity having the protective film formed thereon.
    Type: Application
    Filed: March 11, 2009
    Publication date: September 24, 2009
    Inventors: Atsunori MOCHIDA, Yoshiaki Hasegawa
  • Publication number: 20090170560
    Abstract: A receiver of a wireless base station that uses a simple mode to detect a failure is provided, and an SW 201 switches whether an input port of the receiver 133 is to be connected with an antenna 114 or to be terminated. An LNA (a low noise amplifier) 205 amplifies an input signal with a low distortion. SWs 202 and 203 switch between a first path which runs through the LNA 205 and a second path 204 which does not run through the LNA 205. An AGC AMP, the gain of which is controlled such that the output thereof is constant, amplifies the signal with the controlled gain. A base station control section uses the SW 201 to terminate the input port of the receiver so that thermal noise is input to the LNA 205.
    Type: Application
    Filed: December 19, 2005
    Publication date: July 2, 2009
    Inventors: Yoshiaki Hasegawa, Akihiro Saito, Tomoya Uchiike, Yoshihiro Kanomata
  • Publication number: 20090159921
    Abstract: A nitride semiconductor device according to the present invention includes a n-GaN substrate 10 and a semiconductor multilayer structure arranged on the principal surface of the n-GaN substrate 10 and including a p-type region, an n-type region and an active layer between them. An SiO2 layer 30 with an opening and a p-side electrode, which makes contact with a portion of the p-type region of the semiconductor multilayer structure, are arranged on the upper surface of the semiconductor multilayer structure. An n-side electrode 36 is arranged on the back surface of the substrate 10. The p-side electrode includes a p-side contact electrode 2 that contacts with the portion of the p-type region and a p-side interconnect electrode 34 that covers the p-side contact electrode 2 and the SiO2 layer 30. Part of the p-side contact electrode 32 is exposed under the p-side interconnect electrode 34.
    Type: Application
    Filed: December 27, 2006
    Publication date: June 25, 2009
    Inventors: Yoshiaki Hasegawa, Gaku Sugahara, Toshiya Yokogawa
  • Publication number: 20090135875
    Abstract: A semiconductor laser (101) includes a first cladding layer (103), an active layer (105) and a second cladding layer (108). A window region (115) including fluorine, that is, an impurity element with higher electronegativity than nitrogen, is formed in the vicinity of a front end face (113) and a rear end face (114) of a laser resonator. The window region (115) is formed by exposing the front end face (113) and the rear end face (114) to carbon fluoride (CF4) plasma. The effective band gap of a portion of the active layer (105) disposed in the window region (115) is larger than the effective band gap of another portion of the active layer, and hence, it functions as an end face window structure for suppressing COD.
    Type: Application
    Filed: July 9, 2007
    Publication date: May 28, 2009
    Inventors: Daisuke Ueda, Masaaki Yuri, Yoshiaki Hasegawa, Kenichi Matsuda
  • Patent number: 7501667
    Abstract: A nitride semiconductor light-emitting device is provided including: a substrate made of a nitride semiconductor; a semiconductor layer made of a nitride semiconductor containing a p-type impurity, the semiconductor layer being formed as contacting an upper surface of the substrate; a first cladding layer made of a nitride semiconductor containing an impurity of a first conductivity type, the first cladding layer being formed on the semiconductor layer; an active layer formed on the first cladding layer; and a second cladding layer made of a nitride semiconductor containing an impurity of a second conductivity type, the second cladding layer being formed on the active layer.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: March 10, 2009
    Assignee: Panasonic Corporation
    Inventors: Yoshiaki Hasegawa, Toshiya Yokogawa, Akihiko Ishibashi
  • Publication number: 20090059983
    Abstract: A nitride semiconductor light-emitting device is provided including: a substrate made of a nitride semiconductor; a semiconductor layer made of a nitride semiconductor containing a p-type impurity, the semiconductor layer being formed as contacting an upper surface of the substrate; a first cladding layer made of a nitride semiconductor containing an impurity of a first conductivity type, the first cladding layer being formed on the semiconductor layer; an active layer formed on the first cladding layer; and a second cladding layer made of a nitride semiconductor containing an impurity of a second conductivity type, the second cladding layer being formed on the active layer.
    Type: Application
    Filed: October 27, 2008
    Publication date: March 5, 2009
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
    Inventors: Yoshiaki Hasegawa, Toshiya Yokogawa, Akihiko Ishibashi
  • Publication number: 20090022193
    Abstract: An nitride semiconductor device according to the present invention is a nitride semiconductor device including: an n-GaN substrate 10; a semiconductor multilayer structure 100 formed on a principal face of the n-GaN substrate 10, the semiconductor multilayer structure 100 including a p-type region and an n-type region; a p-side electrode 32 which is in contact with a portion of the p-type region included in the semiconductor multilayer structure 100; and an n-side electrode 34 provided on the rear face of the n-GaN substrate 10. The rear face of the n-GaN substrate includes a nitrogen surface, such that a carbon concentration at an interface between the rear face and the n-side electrode 34 is adjusted to 5 atom % or less.
    Type: Application
    Filed: March 9, 2006
    Publication date: January 22, 2009
    Inventors: Yoshiaki Hasegawa, Gaku Sugahara, Naomi Anzue, Akihiko Ishibashi, Toshiya Yokogawa
  • Publication number: 20080315231
    Abstract: A light source of the present invention includes: a semiconductor light emitting device which has a light emitting face and emits light from part of the light emitting face; a container which has a light transmitting window for transmitting the light and accommodates the semiconductor light emitting device; and a gettering portion for performing gettering of a material containing at least one of carbon and silicon. The gettering portion is positioned, in the container, in a region other than the part of the light emitting face of the semiconductor light emitting device.
    Type: Application
    Filed: June 12, 2008
    Publication date: December 25, 2008
    Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO. LTD.
    Inventors: Isao Kidoguchi, Yasuo Kitaoka, Hiroyoshi Yajima, Keiji Ito, Akihiko Ishibashi, Yoshiaki Hasegawa, Kiminori Mizuuchi
  • Publication number: 20080272462
    Abstract: A nitride-based semiconductor device according to the present invention includes a semiconductor multilayer structure supported on a substrate structure 101 with electrical conductivity. The principal surface of the substrate structure 101 has at least one vertical growth region, which functions as a seed crystal for growing a nitride-based semiconductor vertically, and a plurality of lateral growth regions for allowing the nitride-based semiconductor that has grown on the vertical growth region to grow laterally. The sum ?X of the respective sizes of the vertical growth regions as measured in the direction pointed by the arrow A and the sum ?Y of the respective sizes of the lateral growth regions as measured in the same direction satisfy the inequality ?X/?Y>1.0.
    Type: Application
    Filed: November 15, 2005
    Publication date: November 6, 2008
    Inventors: Toshitaka Shimamoto, Yasutoshi Kawaguchi, Yoshiaki Hasegawa, Akihiko Ishibashi, Isao Kidoguchi, Toshiya Yokogawa
  • Publication number: 20080273562
    Abstract: A nitride semiconductor device 100 according to the present invention includes: an n-GaN substrate 1; a semiconductor multilayer structure, which has been formed on the principal surface of the n-GaN substrate 1 and which includes a p-type region and an n-type region; a p-electrode 32, which makes contact with a portion of the p-type region included in the semiconductor multilayer structure; and an n-electrode 34, which is arranged on the bottom surface of the substrate 1. The bottom surface of the substrate 1 includes a roughened region 40a and a flattened region 40b. And the n-electrode 34 covers the roughened region 40a at least partially.
    Type: Application
    Filed: May 12, 2006
    Publication date: November 6, 2008
    Inventors: Yoshiaki Hasegawa, Akihiko Ishibashi, Toshiya Yokogawa
  • Patent number: 7407421
    Abstract: A light source of the present invention includes: a semiconductor light emitting device which has a light emitting face and emits light from part of the light emitting face; a container which has a light transmitting window for transmitting the light and accommodates the semiconductor light emitting device; and a gettering portion for performing gettering of a material containing at least one of carbon and silicon. The gettering portion is positioned, in the container, in a region other than the part of the light emitting face of the semiconductor light emitting device.
    Type: Grant
    Filed: November 19, 2004
    Date of Patent: August 5, 2008
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Isao Kidoguchi, Yasuo Kitaoka, Hiroyoshi Yajima, Keiji Ito, Akihiko Ishibashi, Yoshiaki Hasegawa, Kiminori Mizuuchi
  • Patent number: 7396697
    Abstract: A method for fabricating a semiconductor light-emitting element according to the present invention includes the steps of (A) providing a striped masking layer on a first Group III-V compound semiconductor, (B) selectively growing a second Group III-V compound semiconductor over the entire surface of the first Group III-V compound semiconductor except a portion covered with the masking layer, thereby forming a current confining layer that has a striped opening defined by the masking layer, (C) selectively removing the masking layer, and (D) growing a third Group III-V compound semiconductor to cover the surface of the first Group III-V compound semiconductor, which is exposed through the striped opening, and the surface of the current confining layer.
    Type: Grant
    Filed: April 6, 2004
    Date of Patent: July 8, 2008
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoshiaki Hasegawa, Toshiya Yokogawa, Atsushi Yamada