Information carrier, reading/writing device and reading device for writing and/or reading information blocks

• US 6,167,012 A
• Filed: 02/08/2000
• Issued: 12/26/2000
• Est. Priority Date: 09/03/1996
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Van Den Enden, Gijsbert J., Spruit, Johannes H. M.
• Primary Examiner(s): HINDI, NABIL Z
• Application Number:
  US09/500,303
• Time in Patent Office: 322 Days
• Field of Search: 369/275.3, 369/48, 369/47, 369/44.26, 369/50, 369/44.13
• US Class Current: 369/47.1
• CPC Class Codes: G11B 2220/218 Write-once discs
• CPC Class Codes: G11B 2220/2525 Magneto-optical [MO] discs
• CPC Class Codes: G11B 2220/2545 CDs
• CPC Class Codes: G11B 27/24 by sensing features on the record carrier other than the transducing track ; sensing signals or marks recorded by another method than the main recording
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: G11B 7/007 Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
• CPC Class Codes: G11B 7/0938 servo format, e.g. guide tracks, pilot signals
• CPC Class Codes: G11B 7/0946 specially adapted for operation during external perturbations not related to the carrier or servo beam, e.g. vibration
• CPC Class Codes: G11B 7/24082 Meandering

Abstract

A disc-shaped information carrier has a track thereon which follows a helical or concentric path forming successive windings. For identifying each winding the information carrier also has a servo pattern thereon which includes position-information as well as synchronization elements. Such elements may be, for example, brief pulses in a continuous track wobble, and are distinguishable in adjacent windings based on a predetermined detectable parameter, such as alternating polarity or shifted relative phase positions. During recording by a read/write head a system control detects the synchronization elements and monitors whether a deviation has occurred signifying that the read/write head has wandered to an adjacent winding. In that event recording is interrupted. Thus, the least possible information in adjacent windings is overwritten in the case of disturbances resulting from shocks or defects of the information carrier. A read device is also described which interrupts reading if the winding identification provided by the synchronization elements signifies erroneous operation.

Claims

1. An information carrier having a recording track which follows a helical or concentric path forming successive windings and which is adapted to have information recorded thereon in the form of successive information blocks, the track path being determined by a servo pattern on the information carrier;

said servo pattern comprising;

(i) a modulation of a predetermined detectable physical parameter of the track path in accordance with coded position information, and

(ii) periodic synchronization pulses, the pulses in adjacent track windings being distinguished from each other based on a predetermined substantially fixed difference in at least one predetermined detectable physical parameter of said pulses.

2. An information carrier as claimed in claim 1, wherein the synchronization pulses in adjacent windings are aligned but differ in phase.

4. An information carrier as claimed in claim 1, having recorded thereon an information pattern in the form of successive information blocks.

3. An information carrier as claimed in 1, wherein the modulation of a predetermined physical parameter of the track path comprises a periodic transverse variation of the radial displacement of a pregroove in the information carrier, which pregroove constitutes the track path, and the synchronization pulses are in the form of a short interruption of the pregroove modulation during each period thereof.