Patents by Inventor Hatsumi Matsuura

Hatsumi Matsuura 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: 5495493
    Abstract: According to a semiconductor laser device of the present invention, the thickness and carrier concentration of a current blocking layer are set so as to cause a punch through on the current blocking layer when the semiconductor laser device is driven at a current which is one to ten times as large as a maximum rated value of a DC driving current. Both a light absorbing layer and a photocurrent blocking layer are formed between the current blocking layer and a second clad layer in order to prevent a light turn-on phenomenon from occurring. The light absorbing layer contacts the second clad layer and is constituted of a semiconductor crystal of a p-type conductivity type, which is undoped or has a low concentration. The photocurrent blocking layer contacts the current blocking layer and is constituted of a semiconductor crystal of the p-type conductivity type. If the band gaps of the light absorbing layer, photocurrent blocking layer, and active layer are represented by E.sub.ab, E.sub.ocb, and E.sub.
    Type: Grant
    Filed: October 18, 1994
    Date of Patent: February 27, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Haruki Kurihara, Hatsumi Matsuura