Patents by Inventor Katsuharu Satoh

Katsuharu Satoh 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: 5084850
    Abstract: An apparatus for detecting a focus error signal in which reflected laser light is split into two optical paths by a polarized light beam splitter while astigmatisms are produced in the laser light by at least one astigmatism generating element, and the two split beams are led so as to be incident upon two quadrant photodetectors, respectively. A focus error signal is obtained as an electrical signal by subtracting the sum of the quantities of light received by one of the diagonal pairs of regions among the quadrant regions of the two photodetectors from the sum of the quantities of light received by the other diagonal pair. An offset component in a focus error signal is removed by, for example, a variable resistor. This arrangement enables cancelling of influence of double refraction in a magnetooptic disk or the like, thereby making the optical head free of the problem of such influence.
    Type: Grant
    Filed: March 1, 1990
    Date of Patent: January 28, 1992
    Assignee: Pioneer Electronic Corporation
    Inventors: Naoharu Yanagawa, Katsuharu Satoh