Patents by Inventor Hisayoshi Kitajima

Hisayoshi Kitajima 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: 10063027
    Abstract: The present invention provides a semiconductor laser device for improving temperature characteristics of waveguide structures and realizing stable light emitting patterns and high output, and a method for making the same. The semiconductor laser device (1) comprises: an n-type clad layer (5) laminated on a substrate (2); an active layer (6) laminated on the n-type clad layer (5); a p-type clad layer (7) laminated on the active layer (6); and a plurality of waveguide structures (8) formed on the p-type clad layer (7) and having a ridge of a horn shape in top view. In this configuration, a divider (29) is formed between adjacent waveguide structures (8), and the divider (29) comprises: a groove (30) dividing the active layer (6); and a heat dissipation material (34) filled in the groove (30) and having a thermal conductivity higher than a thermal conductivity of a semiconductor layer (4).
    Type: Grant
    Filed: May 15, 2017
    Date of Patent: August 28, 2018
    Assignee: ROHM CO., LTD.
    Inventor: Hisayoshi Kitajima
  • Publication number: 20170338622
    Abstract: The present invention provides a semiconductor laser device for improving temperature characteristics of waveguide structures and realizing stable light emitting patterns and high output, and a method for making the same. The semiconductor laser device (1) comprises: an n-type clad layer (5) laminated on a substrate (2); an active layer (6) laminated on the n-type clad layer (5); a p-type clad layer (7) laminated on the active layer (6); and a plurality of waveguide structures (8) formed on the p-type clad layer (7) and having a ridge of a horn shape in top view. In this configuration, a divider (29) is formed between adjacent waveguide structures (8), and the divider (29) comprises: a groove (30) dividing the active layer (6); and a heat dissipation material (34) filled in the groove (30) and having a thermal conductivity higher than a thermal conductivity of a semiconductor layer (4).
    Type: Application
    Filed: May 15, 2017
    Publication date: November 23, 2017
    Inventor: Hisayoshi KITAJIMA
  • Patent number: 7116692
    Abstract: A semiconductor laser device having a lower cladding layer, an active layer and an upper first cladding layer stacked on a compound semiconductor substrate in this order, a ridge-shaped upper second cladding layer provided on the upper first cladding layer, a current blocking layer provided on both sides of the upper second cladding layer, and a contact layer provided on the upper second cladding layer. A current interrupting layer or layers formed of an insulating material are provided between the upper second cladding layer and the contact layer, in the vicinity of at least one of a laser emission end face and a reflective end face, which are both end faces of the device in the longitudinal direction of the upper second cladding layer.
    Type: Grant
    Filed: December 10, 2002
    Date of Patent: October 3, 2006
    Assignee: Rohm Co., Ltd.
    Inventors: Takashi Kimura, Hisayoshi Kitajima
  • Patent number: 6711198
    Abstract: A light source device for a laser beam printer in which a semiconductor laser is driven with a pulse current having a minimum pulse width at the ON time on the order of milliseconds or less is provided, wherein the semiconductor laser is formed so that either the rate of change at the rise portion of the pulse current becomes ±8% or less or the semiconductor laser is excited in a multiple mode in the vicinity of the threshold value of the oscillation, and the semiconductor laser oscillates in a single mode at a current separated from the threshold value, by adjusting of at least one of the width w of a stripe groove (7a) of the current block layer, the composition of clad layers (5), the distance d between the current block layer (7) and the active layer (4), the composition of the current block layer (7) and the formation of a light absorption layer into the current block layer (7).
    Type: Grant
    Filed: April 14, 2000
    Date of Patent: March 23, 2004
    Assignee: Rohm Co. Ltd.
    Inventors: Jun Ichihara, Hisayoshi Kitajima, Tetsuhiro Tanabe, Ken Nakahara, Haruo Tanaka
  • Publication number: 20030133484
    Abstract: A semiconductor laser device having a lower cladding layer, an active layer and an upper first cladding layer stacked on a compound semiconductor substrate in this order, a ridge-shaped upper second cladding layer provided on the upper first cladding layer, a current blocking layer provided on both sides of the upper second cladding layer, and a contact layer provided on the upper second cladding layer. A current interrupting layer or layers formed of an insulating material are provided between the upper second cladding layer and the contact layer, in the vicinity of at least one of a laser emission end face and a reflective end face, which are both end faces of the device in the longitudinal direction of the upper second cladding layer.
    Type: Application
    Filed: December 10, 2002
    Publication date: July 17, 2003
    Inventors: Takashi Kimura, Hisayoshi Kitajima