Patents by Inventor Hiromitsu Sakai

Hiromitsu Sakai 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: 8896085
    Abstract: A semiconductor light-emitting element manufacturing method including: a first step in which a first n-type semiconductor layer is laminated onto a substrate in a first organometallic chemical vapor deposition apparatus; and a second step in which a regrowth layer, a second n-type semiconductor layer, an active layer, and a p-type semiconductor layer are sequentially laminated onto the aforementioned first n-type semiconductor layer in a second organometallic chemical vapor deposition apparatus.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: November 25, 2014
    Assignee: Toyoda Gosei Co., Ltd.
    Inventor: Hiromitsu Sakai
  • Patent number: 8867247
    Abstract: A commanded negative-sequence current is added to a commanded current so as to suppress double-frequency pulsation on the DC side. The commanded negative-sequence current is found from three values (i.e., the detected value of positive-sequence voltage vector on the power-supply side, the detected value of negative-sequence voltage vector, and a commanded positive-sequence current). Thus, the pulsations which occur on the DC side of a semiconductor power converter and which have a frequency double the power-supply frequency are suppressed even when the AC power supply is at fault while assuring stability of the current control system, thus permitting stable and continuous operation.
    Type: Grant
    Filed: March 15, 2012
    Date of Patent: October 21, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Akira Bando, Yasuhiro Kiyofuji, Masaya Ichinose, Hiromitsu Sakai, Yasuhiro Imazu
  • Patent number: 8859313
    Abstract: A method for manufacturing a semiconductor light emitting element (1) which includes a first step of forming a first n-type semiconductor layer (12c) on a substrate (11) and a second step of sequentially forming a regrowth layer (12d) of the first n-type semiconductor layer (12c), a second n-type semiconductor layer (12b), a light emitting layer (13), and a p-type semiconductor layer (14) on the first n-type semiconductor layer (12c). In the step of forming the second n-type semiconductor layer (12b), a step (1) of supplying Si less than that forming the regrowth layer (12d) as a dopant to form a first layer of the second n-type semiconductor layer and a step (2) of supplying the Si more than that in the step (1) to form a second layer of the second n-type semiconductor layer are performed in this order.
    Type: Grant
    Filed: February 28, 2011
    Date of Patent: October 14, 2014
    Assignee: Toyoda Gosei Co., Ltd.
    Inventor: Hiromitsu Sakai
  • Patent number: 8785227
    Abstract: Provided is a method of manufacturing a semiconductor light emitting element that is capable of making a light emitting wavelength distribution ? of a semiconductor light emitting layer that is obtained small. The method includes a process of laminating a re-growth layer of a compound semiconductor layer on the compound semiconductor substrate which is obtained by forming at least one compound semiconductor layer on a substrate and in which a warping amount H is within a range of 50 ?m?H?250 ?m. The method adopts a method of manufacturing a semiconductor light emitting element including an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer that are formed from a compound semiconductor.
    Type: Grant
    Filed: June 23, 2011
    Date of Patent: July 22, 2014
    Assignee: Toyoda Gosei Co., Ltd.
    Inventor: Hiromitsu Sakai
  • Patent number: 8772060
    Abstract: The present invention provides a method for manufacturing a group III nitride semiconductor light emitting element, with which warping can be suppressed upon the formation of respective layers on the substrate, a semiconductor layer including a light emitting layer of excellent crystallinity can be formed, and excellent light emission characteristics can be obtained; such a group III nitride semiconductor light emitting element; and a lamp. Specifically disclosed is a method for manufacturing a group III nitride semiconductor light emitting element, in which an intermediate layer, an underlayer, an n-type contact layer, an n-type cladding layer, a light emitting layer, a p-type cladding layer, and a p-type contact layer are laminated in sequence on a principal plane of a substrate, wherein a substrate having a diameter of 4 inches (100 mm) or larger, with having an amount of warping H within a range from 0.
    Type: Grant
    Filed: September 14, 2009
    Date of Patent: July 8, 2014
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Hiromitsu Sakai, Takeshi Harada
  • Patent number: 8754441
    Abstract: The semiconductor light-emitting device (11) of the present invention includes a substrate (1); a laminate semiconductor layer (15) comprised of an n-type semiconductor layer (3) formed on the substrate (1), a light-emitting layer (4) laminated on the n-type semiconductor layer (3) and a p-type semiconductor layer (5) laminated on the light-emitting layer (4); a concavo-convex part (33) for improving a light extraction efficiency, which is formed on all or a part of a top surface (15a) of the laminate semiconductor layer (15); a high-concentration p-type semiconductor layer (8) having a higher dopant concentration than that of the p-type semiconductor layer (5), which is laminated on a convex part (33a) that constitutes the concavo-convex part (33) of the laminate semiconductor layer (15); and a translucent current diffusion layer (20) laminated on at least the high-concentration p-type semiconductor layer (8).
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: June 17, 2014
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Hironao Shinohara, Hiromitsu Sakai
  • Patent number: 8492186
    Abstract: The present invention is a method for producing a group III nitride semiconductor layer in which a single crystal group III nitride semiconductor layer (103) is formed on a substrate (101), the method including: a substrate processing step of forming, on the (0001) C-plane of the substrate (101), a plurality of convex parts (12) of surfaces (12c) not parallel to the C-plane, to thereby form, on the substrate, an upper surface (10) that is composed of the convex parts (12) and a flat surface (11) of the C-plane; and an epitaxial step of epitaxially growing the group III nitride semiconductor layer (103) on the upper surface (10), to thereby embed the convex parts (12) in the group III nitride semiconductor layer (103).
    Type: Grant
    Filed: December 19, 2007
    Date of Patent: July 23, 2013
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Hironao Shinohara, Hiromitsu Sakai
  • Publication number: 20130168691
    Abstract: Provided is a method of manufacturing a semiconductor light emitting element that is capable of making a light emitting wavelength distribution ? of a semiconductor light emitting layer that is obtained small. The method includes a process of laminating a re-growth layer of a compound semiconductor layer on the compound semiconductor substrate which is obtained by forming at least one compound semiconductor layer on a substrate and in which a warping amount H is within a range of 50 ?m?H?250 ?m. The method adopts a method of manufacturing a semiconductor light emitting element including an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer that are formed from a compound semiconductor.
    Type: Application
    Filed: June 23, 2011
    Publication date: July 4, 2013
    Applicant: TOYODA GOSEI CO., LTD.
    Inventor: Hiromitsu Sakai
  • Patent number: 8421107
    Abstract: A group III nitride semiconductor light emitting device including an LED structure formed on top of a single crystal, base layer (103) formed on top of a substrate (101) including a principal plane (10) having a flat surface (11) configured from a (0001) C plane, and a plurality of convex portions (12) including a surface (12c) non-parallel to the C plane having a width (d1) of 0.05 to 1.5 ?m and height (H) of 0.05 to 1 ?m, the base layer is formed by causing a group III nitride semiconductor to grow epitaxially so as to cover the flat surface and convex portions, and the width (d1) of the convex portions and top portion thickness (H2) of the base layer at the positions of the top portions (12e) of the convex portions satisfy: H2=kd1 (wherein 0.5<k<5, and H2=0.5 ?m or more).
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: April 16, 2013
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Hironao Shinohara, Hiromitsu Sakai
  • Publication number: 20120326169
    Abstract: Provided is a method for manufacturing a semiconductor light emitting element (1) in which a defect is less likely to occur in a light emitting layer and a p-type semiconductor layer due to the surface of a second n-type semiconductor layer and which is capable of obtaining a high output. The method for manufacturing a semiconductor light emitting element includes a first step of forming a first n-type semiconductor layer (12c) on a substrate (11) and a second step of sequentially forming a regrowth layer (12d) of the first n-type semiconductor layer (12c), a second n-type semiconductor layer (12b), a light emitting layer (13), and a p-type semiconductor layer (14) on the first n-type semiconductor layer (12c).
    Type: Application
    Filed: February 28, 2011
    Publication date: December 27, 2012
    Applicant: SHOWA DENKO K.K.
    Inventor: Hiromitsu Sakai
  • Patent number: 8309982
    Abstract: Provided is a group-III nitride semiconductor light-emitting device which has a high level of crystallinity and superior internal quantum efficiency and which is capable of enabling acquisition of high level light emission output, and a manufacturing method thereof, and a lamp. An AlN seed layer composed of a group-III nitride based compound is laminated on a substrate 11, and on this AlN seed layer, there are sequentially laminated each layer of an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer respectively composed of a group-III nitride semiconductor, wherein the full width at half-maximum of the X-ray rocking curve of the (0002) plane of the p-type semiconductor layer 16 is 60 arcsec or less, and the full width at half-maximum of the X-ray rocking curve of the (10-10) plane is 250 arcsec or less.
    Type: Grant
    Filed: June 11, 2009
    Date of Patent: November 13, 2012
    Assignee: Showa Denko K.K.
    Inventors: Kenzo Hanawa, Hiromitsu Sakai, Yasumasa Sasaki
  • Patent number: 8299642
    Abstract: A wind power generation system includes an excessive current consumption device, an AC input of which is connected between a generator rotor and an excitation converter on a system failure to detect a DC voltage ascent of the excitation converter and operate a shunt circuit on the system failure.
    Type: Grant
    Filed: February 9, 2010
    Date of Patent: October 30, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masaya Ichinose, Motoo Futami, Hiromitsu Sakai, Kazuhiro Imaie
  • Publication number: 20120170333
    Abstract: A commanded negative-sequence current is added to a commanded current so as to suppress double-frequency pulsation on the DC side. The commanded negative-sequence current is found from three values (i.e., the detected value of positive-sequence voltage vector on the power-supply side, the detected value of negative-sequence voltage vector, and a commanded positive-sequence current). Thus, the pulsations which occur on the DC side of a semiconductor power converter and which have a frequency double the power-supply frequency are suppressed even when the AC power supply is at fault while assuring stability of the current control system, thus permitting stable and continuous operation.
    Type: Application
    Filed: March 15, 2012
    Publication date: July 5, 2012
    Applicant: Hitachi, Ltd.
    Inventors: Akira Bando, Yasuhiro Kiyofuji, Masaya Ichinose, Hiromitsu Sakai, Yasuhiro Imazu
  • Publication number: 20120113658
    Abstract: A semiconductor light-emitting element manufacturing method including: a first step in which a first n-type semiconductor layer is laminated onto a substrate in a first organometallic chemical vapor deposition apparatus; and a second step in which a regrowth layer, a second n-type semiconductor layer, an active layer, and a p-type semiconductor layer are sequentially laminated onto the aforementioned first n-type semiconductor layer in a second organometallic chemical vapor deposition apparatus.
    Type: Application
    Filed: July 9, 2010
    Publication date: May 10, 2012
    Applicant: SHOWA DENKO K.K.
    Inventor: Hiromitsu Sakai
  • Patent number: 8148712
    Abstract: An object of the present invention is to obtain a group III nitride compound semiconductor stacked structure where a group III nitride compound semiconductor layer having good crystallinity is stably stacked on a dissimilar substrate. The group III nitride compound semiconductor stacked structure of the present invention is a group III nitride compound semiconductor stacked structure comprising a substrate having provided thereon a first layer comprising a group III nitride compound semiconductor and a second layer being in contact with the first layer and comprising a group III nitride compound semiconductor, wherein the first layer contains a columnar crystal with a definite crystal interface and the columnar crystal density is from 1×103 to 1×105 crystals/?m2.
    Type: Grant
    Filed: May 8, 2007
    Date of Patent: April 3, 2012
    Assignee: Showa Denko K.K.
    Inventors: Hisayuki Miki, Hiromitsu Sakai, Kenzo Hanawa, Yasunori Yokoyama, Yasumasa Sasaki, Hiroaki Kaji
  • Patent number: 8134168
    Abstract: An object of the present invention is to provide a Group III nitride semiconductor element which comprises a thick AlGaN layer exhibiting high crystallinity and containing no cracks, and which does not include a thick GaN layer (which generally serves as a light-absorbing layer in an ultraviolet LED). The inventive Group III nitride semiconductor element comprises a substrate; a first nitride semiconductor layer composed of AlN which is provided on the substrate; a second nitride semiconductor layer composed of Alx1Ga1-x1N (0?x1?0.1) which is provided on the first nitride semiconductor layer; and a third nitride semiconductor layer composed of Alx2Ga1-x2N (0<x2<1 and x1+0.02?x2) which is provided on the second nitride semiconductor layer.
    Type: Grant
    Filed: October 13, 2004
    Date of Patent: March 13, 2012
    Assignee: Showa Denko K.K.
    Inventors: Hiromitsu Sakai, Mineo Okuyama
  • Patent number: 8129851
    Abstract: In a wind power generation system, an energy consuming unit is connected to a DC part of a generator-side converter. A shunt circuit is connected between the generator-side converter and a rotor of an AC-excited power generator. In the event of system failure, the switching operation of the converter is stopped, the shunt circuit is put into operation, and the energy consuming unit is put into operation so that DC voltage (voltage of the DC part) is maintained within a prescribed range.
    Type: Grant
    Filed: June 2, 2008
    Date of Patent: March 6, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masaya Ichinose, Motoo Futami, Hiromitsu Sakai, Kojiro Yamashita
  • Publication number: 20120049521
    Abstract: To shorten a startup interval to reach a synchronizing condition, a phase difference and an amplitude difference between the grid voltage and the stator voltage of one phase of a winding are obtained. The difference in amplitude is decreased prior to or in parallel to synchronizing the stator voltage with the grid voltage. The calculated compensation phase compensation value is used as an initial value for synchronizing at the next synchronizing operation.
    Type: Application
    Filed: November 7, 2011
    Publication date: March 1, 2012
    Applicant: HITACHI, LTD.
    Inventors: Masaya ICHINOSE, Motoo FUTAMI, Hiromitsu SAKAI
  • Patent number: 8097971
    Abstract: In a wind turbine generator system including an AC exciting converter a grid side converter, and a controller configured to control the AC-exciting converter and the grid side converter, the controller operates a short-circuiting circuit when decrease in the grid voltage and increase in the DC voltage are detected.
    Type: Grant
    Filed: May 6, 2009
    Date of Patent: January 17, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masaya Ichinose, Motoo Futami, Hiromitsu Sakai
  • Patent number: 8076790
    Abstract: To shorten a startup interval to reach a synchronizing condition, a phase difference and an amplitude difference between the grid voltage and the stator voltage of one phase of a winding are obtained. The difference in amplitude is decreased prior to or in parallel to synchronizing the stator voltage with the grid voltage. The calculated compensation phase compensation value is used as an initial value for synchronizing at the next synchronizing operation.
    Type: Grant
    Filed: May 13, 2011
    Date of Patent: December 13, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Masaya Ichinose, Motoo Futami, Hiromitsu Sakai