Patents by Inventor Yohei Wakai

Yohei Wakai 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: 20130285109
    Abstract: A sapphire substrate having a principal surface for growing a nitride semiconductor to form a nitride semiconductor light emitting device comprises a plurality of projections on the principal surface. Each of the projections has a bottom that has a substantially polygonal shape. Each side of the bottom of the projections has a depression in its center. Vertexes of the bottoms of the respective projections extend in a direction that is within a range of ±10 degrees of a direction that is rotated counter-clockwise by 30 degrees from a crystal axis “a” of the sapphire substrate.
    Type: Application
    Filed: March 14, 2013
    Publication date: October 31, 2013
    Inventors: Junya NARITA, Takuya OKADA, Yohei WAKAI, Yoshiki INOUE, Naoya SAKO, Katsuyoshi KADAN
  • Publication number: 20130270593
    Abstract: A sapphire substrate having a principal surface for growing a nitride semiconductor to form a nitride semiconductor light emitting device comprises a plurality of projections on the principal surface. Each of the projections has a bottom that has a substantially polygonal shape. Each side of the bottom of the projections has a depression in its center. Vertexes of the bottoms of the respective projections extend in a direction that is within a range of ±10 degrees of a direction that is rotated clockwise by 30 degrees from a crystal axis “a” of the sapphire substrate.
    Type: Application
    Filed: March 14, 2013
    Publication date: October 17, 2013
    Inventors: Junya NARITA, Takuya OKADA, Yohei WAKAI, Yoshiki INOUE, Naoya SAKO, Katsuyoshi KADAN
  • Patent number: 8552445
    Abstract: A semiconductor light emitting device having high reliability and excellent light distribution characteristics is provided. Specifically, a semiconductor light emitting device 1 is provided with an n-electrode 50, which is arranged on a light extraction surface on the side opposite to the surface whereupon a semiconductor stack 40 is mounted on a substrate 10. A plurality of convexes are arranged on a first convex region 80 and a second convex region 90 on the light extraction surface. The second convex region 90 adjoins to the interface between the n-electrode 50 and the semiconductor stack 40, between the first convex region 80 and the n-electrode 50.
    Type: Grant
    Filed: December 26, 2008
    Date of Patent: October 8, 2013
    Assignee: Nichia Corporation
    Inventors: Yohei Wakai, Hiroaki Matsumura, Kenji Oka
  • Patent number: 8394652
    Abstract: A light emitting element having a recess-protrusion structure on a substrate is provided. A semiconductor light emitting element 100 has a light emitting structure of a semiconductor 20 on a first main surface of a substrate 10. The first main surface of the substrate 10 has substrate protrusion portion 11, the bottom surface 14 of each protrusion is wider than the top surface 13 thereof in a cross-section, or the top surface 13 is included in the bottom surface 14 in a top view of the substrate. The bottom surface 14 has an approximately polygonal shape, and the top surface 13 has an approximately circular or polygonal shape with more sides than that of the bottom surface 14.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: March 12, 2013
    Assignee: Nichia Corporation
    Inventors: Shunsuke Minato, Junya Narita, Yohei Wakai, Yukio Narukawa, Motokazu Yamada
  • Patent number: 8236591
    Abstract: A method for manufacturing a semiconductor light emitting element from a wafer in which a gallium nitride compound semiconductor has been laminated on a sapphire substrate having an orientation flat, comprises of: laminating a semiconductor layer on a first main face of the sapphire substrate having an off angle ? in a direction Xo parallel to the orientation flat; forming a first break groove that extends in a direction Y substantially perpendicular to the direction Xo, on the semiconductor layer side; forming a second break line that is shifted by a predetermined distance in the ±Xo direction from a predicted split line within the first break groove and parallel to the first break groove in the interior of the sapphire substrate and corresponding to the inclination of the off angle ?; and splitting the wafer along the first and/or second break line.
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: August 7, 2012
    Assignee: Nichia Corporation
    Inventors: Takashi Ichihara, Hirofumi Yoshida, Takao Yamada, Yohei Wakai
  • Publication number: 20120074431
    Abstract: The sapphire substrate has a principal surface for growing a nitride semiconductor to form a nitride semiconductor light emitting device and comprising a plurality of projections of the principal surface, wherein an outer periphery of a bottom surface of each of the projections has at least one depression. This depression is in the horizontal direction. The plurality of projections are arranged so that a straight line passes through the inside of at least any one of projections when the straight line is drawn at any position in any direction in a plane including the bottom surfaces of the plurality of projections.
    Type: Application
    Filed: August 5, 2011
    Publication date: March 29, 2012
    Inventors: Junya NARITA, Takuya Okada, Yohei Wakai, Yoshiki Inoue, Naoya Sako, Katsuyoshi Kadan
  • Publication number: 20110316041
    Abstract: A sapphire substrate having one principal surface on which a nitride semiconductor is grown, said one principal surface having a plurality of projections. Each of the projections has a generally pyramidal shape with a not truncated, more sharpened tip and with an inclined surface composed of a crystal growth-suppression surface that lessens or suppresses the growth of the nitride semiconductor and also which has an inclination change line at which an inclination angle discontinuously varies.
    Type: Application
    Filed: June 24, 2011
    Publication date: December 29, 2011
    Inventors: Junya NARITA, Yohei Wakai, Takayoshi Wakaki
  • Publication number: 20100264443
    Abstract: A semiconductor light emitting device having high reliability and excellent light distribution characteristics is provided. Specifically, a semiconductor light emitting device 1 is provided with an n-electrode 50, which is arranged on a light extraction surface on the side opposite to the surface whereupon a semiconductor stack 40 is mounted on a substrate 10. A plurality of convexes are arranged on a first convex region 80 and a second convex region 90 on the light extraction surface. The second convex region 90 adjoins to the interface between the n-electrode 50 and the semiconductor stack 40, between the first convex region 80 and the n-electrode 50.
    Type: Application
    Filed: December 26, 2008
    Publication date: October 21, 2010
    Applicant: NICHIA CORPORATION
    Inventors: Yohei Wakai, Hiroaki Matsumura, Kenji Oka
  • Publication number: 20100255621
    Abstract: A light emitting element having a recess-protrusion structure on a substrate is provided. A semiconductor light emitting element 100 has a light emitting structure of a semiconductor 20 on a first main surface of a substrate 10. The first main surface of the substrate 10 has substrate protrusion portion 11, the bottom surface 14 of each protrusion is wider than the top surface 13 thereof in a cross-section, or the top surface 13 is included in the bottom surface 14 in a top view of the substrate. The bottom surface 14 has an approximately polygonal shape, and the top surface 13 has an approximately circular or polygonal shape with more sides than that of the bottom surface 14.
    Type: Application
    Filed: June 15, 2010
    Publication date: October 7, 2010
    Inventors: Shunsuke MINATO, Junya Narita, Yohei Wakai, Yukio Narukawa, Motokazu Yamada
  • Patent number: 7781790
    Abstract: A semiconductor light emitting element having a semiconductor light emitting structure on a first main surface of a substrate, wherein the first main surface of the substrate has a substrate protrusion portion thereon, wherein a bottom surface of a protrusion is wider than a top surface thereof in a cross section of the substrate and the top surface is included in the bottom surface in a top view of the substrate, the bottom surface has an approximately polygonal shape which has a convex portion on each constituent side of the bottom surface, and the top surface has an approximately circular shape.
    Type: Grant
    Filed: December 20, 2007
    Date of Patent: August 24, 2010
    Assignee: Nichia Corporation
    Inventors: Shunsuke Minato, Junya Narita, Yohei Wakai, Yukio Narukawa, Motokazu Yamada
  • Publication number: 20100187542
    Abstract: A method for manufacturing a semiconductor light emitting element from a wafer in which a gallium nitride compound semiconductor has been laminated on a sapphire substrate having an orientation flat, comprises of: laminating a semiconductor layer on a first main face of the sapphire substrate having an off angle ? in a direction Xo parallel to the orientation flat; forming a first break groove that extends in a direction Y substantially perpendicular to the direction Xo, on the semiconductor layer side; forming a second break line that is shifted by a predetermined distance in the ±Xo direction from a predicted split line within the first break groove and parallel to the first break groove in the interior of the sapphire substrate and corresponding to the inclination of the off angle ?; and splitting the wafer along the first and/or second break line.
    Type: Application
    Filed: July 31, 2008
    Publication date: July 29, 2010
    Applicant: NICHIA CORPORATION
    Inventors: Takashi Ichihara, Hirofumi Yoshida, Takao Yamada, Yohei Wakai
  • Publication number: 20100072501
    Abstract: A semiconductor light emitting device which includes at least one concave on a light extraction surface opposite to a surface on which a semiconductor stack comprising a light emitting layer between a n-type semiconductor layer and a p-type semiconductor layer is mounted. The concave has not less than two slopes each having a different slope angle in a direction that a diameter of the concave becomes narrower toward a bottom of the concave from an opening of the concave and a slope having a gentle slope angle is provided with irregularities and a slope having a steep slope angle is a flat surface.
    Type: Application
    Filed: September 17, 2009
    Publication date: March 25, 2010
    Applicant: NICHIA CORPORATION
    Inventors: Yohei WAKAI, Masahiko ONISHI
  • Publication number: 20080303042
    Abstract: A light emitting element having a recess-protrusion structure on a substrate is provided. A semiconductor light emitting element 100 has a light emitting structure of a semiconductor 20 on a first main surface of a substrate 10. The first main surface of the substrate 10 has substrate protrusion portion 11, the bottom surface 14 of each protrusion is wider than the top surface 13 thereof in a cross-section, or the top surface 13 is included in the bottom surface 14 in a top view of the substrate. The bottom surface 14 has an approximately polygonal shape, and the top surface 13 has an approximately circular or polygonal shape with more sides than that of the bottom surface 14.
    Type: Application
    Filed: December 20, 2007
    Publication date: December 11, 2008
    Applicant: NICHIA CORPORATION
    Inventors: Shunsuke Minato, Junya Narita, Yohei Wakai, Yukio Narukawa, Motokazu Yamada