Patents by Inventor Sunny K. Ksu

Sunny K. Ksu 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: 4816665
    Abstract: Method and apparatus for astigmatic focusing control which is independent of intensity distribution and is implemented with a combined data/focus error sensor array is described. An objective lens is utilized to focus a laser beam for use in reading and/or writing in an optical disk storage system. An astigmatic focus control system is utilized in which a cylindrical lens is disposed in the path of light reflected from the optical disk. The light from the cylindrical lens forms an astigmatic image on a sensor array. The image shifts between a circle at the focal point and one of two ellipses disposed orthoganally to each other depending on whether the focal point of the objective lens is above or below the plane of the optical disk. In the preferred embodiment, a circular bi-cell sensor is disposed so as to receive and encompass a reflected beam through the cylindrical lens when the objective lens is "in focus". An outer array of four sensors is disposed symetrically about the central bi-cell.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: March 28, 1989
    Assignee: Maxtor Corporation
    Inventor: Sunny K. Ksu