Multi-format optical disk and reading device

• US 4,967,403 A
• Filed: 04/20/1988
• Issued: 10/30/1990
• Est. Priority Date: 08/25/1986
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ogawa, Hiroshi, Sako, Yoichiro
• Primary Examiner(s): McElheny, Jr., Donald
• Application Number:
  US07/196,013
• Time in Patent Office: 923 Days
• Field of Search: 369/275, 369/111, 369/43, 369/44, 369/45, 369/46, 369/32, 369/26, 369/275.3, 360/77.03, 360/77.08
• US Class Current: 369/44.26
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 2020/10888 the kind of data being the selection criterion
• CPC Class Codes: G11B 21/106 on disks
• CPC Class Codes: G11B 2220/2525 Magneto-optical [MO] discs
• CPC Class Codes: G11B 2220/2537 Optical discs
• CPC Class Codes: G11B 7/013 for discrete information, i.e. where each information unit is stored in a distinct discrete location , e.g. digital information formats within a data block or sector
• CPC Class Codes: G11B 7/0938 servo format, e.g. guide tracks, pilot signals
• CPC Class Codes: G11B 7/24085 Pits

Abstract

A disk device which reproduces at least a disk (1) in which a servo signal region (3) in which a pit for servo and the like are formed and a data and address signal region (4) on which data and address are written are alternatingly provided along the circumferential direction of the disk (1), and in which signals are recorded depending upon two or more kinds of physical changes on the data and address signal regions (4) among the servo signal regions (3). A signal recorded depending upon one physical change is switched into a signal recorded depending upon another physical change in the servo signal region (3) or in a no-signal recording region (5c). Therefore, margin is provided for the operation of switching the signals of various recording types, and stable operation can be maintained even when the data are transferred at higher speeds.

Claims

1. A disk apparatus for at least reproducing a disk-shaped recording medium wherein servo signal regions in which pits for tracking are recorded at alternately offset positions with respect to the center of the track and pits for clock generation are recorded at the center position of the track, as servo signals, and data address signal regions into which at least data signals and address signals are written are formed alternately in the circumferential direction of the disk, and wherein signals are recorded in either a first signal format or a second signal format in each said data address signal region, such that there are signals in only one of said formats in any one of said data address signal regions, comprising:

a pickup for reading said signals in said data address regions in said first and second formats; and

switching means responsive to said servo signals for switching between said signals recorded in said first change from said format and those recorded in said second format, such that switching takes place while said servo signal region is being read.

2. A disk apparatus according to claim 1 wherein said servo signals and said address signals are previously recorded on said disk-shaped recording medium as projections and recesses in the disk as said first format and said data signals are recorded photo-magnetically as said second format.

3. A disk apparatus according to claim 1 wherein the servo signal region on said disk-like recording medium has a length of 15 to 30 microns.

4. A disk-shaped recording medium for use in an apparatus for reading said medium, comprising a disk having tracks containing alternating servo signal regions and data address signal regions formed circumferentially around said disk, wherein said servo signal regions contain pits for tracking recorded at alternately offset positions with respect to the center of the track and pits for clock generation recorded at the center position of the track, as servo signals, and said data address signal regions contain at least data signals and address signals written in either a first or second signal format, and wherein signals recorded in said first format and signals recorded in said second format are separated by either a recording area sufficient to allow said apparatus for reading said disk to switch between the signals recorded in said first format and the signals recorded in said second format or one of said servo signal regions.

5. The disk recording medium according to claim 4, wherein said servo signals and said address signals are recorded in said first signal format as the change in the shape of projections and recesses and said data signals are recorded photo-magnetically in said second signal format.

6. A disk recording medium according to claim 4 wherein said servo signal region has the length of 15 to 30 microns.