Patents by Inventor Takashi Tsubota

Takashi Tsubota 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: 4975752
    Abstract: An LED includes a semiconductor substrate, a first blocking layer formed on this semiconductor substrate, a second blocking layer formed on this first blocking layer, a first V-channel extending from the second blocking layer to the semiconductor substrate, and a stripe-geometry light-emitting region formed in the first V-channel. Light is emitted from the LED from one edge of the light-emitting region due to a flow of current in the light-emitting region, to which the current is confined by the blocking layers. The LED also comprises a second V-channel disposed at a certain distance from the other edge of the light-emitting region, on the optical path of the light emitted from this other edge, and an absorbing region is formed in the second V-channel. This absorbing region absorbs the light emitted from the other edge of the light-emitting region. The LED has excellent characteristics in which a stable output of spontaneously-emitted light can be obtained under a wide variety of operating conditions.
    Type: Grant
    Filed: September 28, 1988
    Date of Patent: December 4, 1990
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Yasumasa Kashima, Masao Kobayashi, Takashi Tsubota