Title:
【発明の名称】光ディスク装置および光ディスク
Document Type and Number:
Japanese Patent JP2569005
Kind Code:
B2
Abstract:
An optical memory apparatus employs an optical disc having a plurality of guide-grooves in spiral and concentrical form and a plurality of flat tracks each arranged between adjacent two of the guide-grooves for recording information thereon, and the depth of the guide-grooves is suitably selected to increase the degree of modulation of a track cross signal, thereby performing a stable cross track counting by the use of the track cross signal and a tracking signal. One feature of the invention relies in that the modulation degree of the track cross signal is in the range between 30 and 60%. A second feature of the invention is that the guide-grooves are formed into a V shape and have an optical depth of lambda /6 to lambda /5 ( lambda is the wavelength of the light used). In accordance with the invention, not ony a stable cross track counting is realized, but also the tracking signal is not practically varied with variations in the depth of the guide-grooves, thereby ensuring a highly accurate and stable tracking control.
Inventors:
Toshimitsu Kaku
Takeshi Maeda
Shigeru Nakamura
Itoh
Kazuo Shigematsu
Yoshito Tsunoda
Takeshi Maeda
Shigeru Nakamura
Itoh
Kazuo Shigematsu
Yoshito Tsunoda
Application Number:
JP7097186A
Publication Date:
January 08, 1997
Filing Date:
March 31, 1986
Export Citation:
Assignee:
株式会社日立製作所
International Classes:
G11B7/00; G11B7/005; G11B7/007; G11B7/085; G11B7/09; G11B7/24073; G11B7/24076; G11B7/24079; G11B7/24085; G11B7/24091; G11B7/24097; (IPC1-7): G11B7/00; G11B7/085; G11B7/24
Domestic Patent References:
| JPS61178743A | ||||
| JPS5788536A |
Attorney, Agent or Firm:
Katsuo Ogawa (1 person outside)