Patents Represented by Law Firm Olieff & Berridge, PLC
  • Information recording and reproduction device
    Patent number: 5936924
    Abstract: An information recording and reproduction device records, erases or reproduces information by projecting a laser beam to a recording medium that has a first group of information tracks and a second group of information tracks, both of which are in a concentric or spiral state, there being a difference in a height of the information tracks of the first group relative to the second group, the tracks of the first group alternating with the tracks of the second group in a radial direction of the recording medium.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: August 10, 1999
    Assignee: Nikon Corporation
    Inventor: Toshihisa Tanaka