Patents Represented by Attorney, Agent or Law Firm Keiji Masak
  • Optical disk having lands and grooves with a reduced track pitch
    Patent number: 6822938
    Abstract: An optical disk has grooves and lands located on the disk. A predetermined distance between the grooves and lands is defined as a predetermined track pitch. The predetermined track pitch is defined in term of a laser wavelength used during an operation. The grooves have a depth “d” in relation to the lands. The depth is related to a parameter variable “a” and a refraction index “n” of a substrate.
    Type: Grant
    Filed: March 24, 2003
    Date of Patent: November 23, 2004
    Assignee: Research Investment Network, Inc.
    Inventors: Hiroyuki Matsumoto, Seiji Morita, Masatoshi Hayashi, Satomi Yoshibe