Optical disk and optical disk apparatus

• US 6,909,681 B2
• Filed: 04/26/2002
• Issued: 06/21/2005
• Est. Priority Date: 04/27/2001
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nagata, Masayoshi, Hideta, Ikuhiro, Tone, Yasuo
• Primary Examiner(s): HINDI, NABIL Z
• Application Number:
  US10/132,948
• Publication Number:
  US 20020191520A1
• Time in Patent Office: 1,152 Days
• Field of Search: 369/59.1, 369/59.11, 369/59.22, 369/59.23
• US Class Current: 369/59.1
• CPC Class Codes: G11B 20/12 Formatting, e.g. arrangement of data block or words on the record carriers within interface between computers and data recorders G06F3/06
• CPC Class Codes: G11B 20/14 using self-clocking codes
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 27/19 by using information detectable on the record carrier
• 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 7/00718 Groove and land recording, i.e. user data recorded both in the grooves and on the lands
• CPC Class Codes: G11B 7/00745 Sectoring or header formats within a track formats in general G11B20/12

Abstract

In an optical disk, address information, including an address information start mark, is recorded in a header region primarily based on variable-length codes such that, between each pair of nearest bits having a first logic value, at least two and at most seven bits having a second logic value are disposed. The address information start mark is detected based on a first criterion that a combination of pulse widths each defined in association with a nearest pair of bits having the first logic value is present in a pulse sequence, and also based on a second criterion that, when the logic level of the pulse sequence alternates between a first logic level and a second logic level in association with occurrence of bits having the first logic value intermittently disposed among bits having the second logic value, the logic levels of pulses in the pulse sequence coincide with their respective counterparts in the combination of pulse widths.

Claims

1. An optical disk having a plurality of sectors constituting tracks arranged spirally or concentrically, each of the plurality of sectors including:

a recording region for recording user data; and

a header region for recording address information including at least one address information start mark for synchronizing with a beginning of address information regarding the position of the sector, the address information start mark being represented by a sequence of pulses having a first logic level and pulses having a second logic level which is an inverse of the first logic level;

wherein the address information is recorded in the header region primarily based on variable-length codes such that, between each pair of nearest bits having a first logic value, at least two and at most seven bits having a second logic value are disposed, the address information start mark being recorded based on either a code permitted for the rest of the address information or a code not permitted for the rest of the address information,

and the address information start mark is detected based on a first detection criterion that a combination of pulse widths each defined in association with a nearest pair of bits having the first logic value is present in a pulse sequence, and also based on a second detection criterion that, when the logic level of the pulse sequence alternates between the first logic level and the second logic level in association with occurrence of each of a plurality of bits having the first logic value intermittently disposed among a plurality of bits having the second logic value, the logic levels of a number of pulses in the pulse sequence respectively coincide with the logic levels of the corresponding pulses constituting the combination of pulse widths.

2. An optical disk according to claim 1, wherein a pulse width of contiguous pulses having the first logic level is in a range of five to nine units of the pulse width of a single pulse having the first logic level, and a pulse width of contiguous pulses having the second logic level is nine units of the pulse width of a single pulse having the second logic level.

3. An optical disk according to claim 1, wherein whether the combination of pulse widths is present is determined with consideration also given to the logic levels of pulses associated with a region preceding the address information start mark.

4. An optical disk according to claim 3, wherein a pulse having the first logic level, associated with the preceding region and nearest to pulses associated with the address information start mark, and a pulse having the first logic level, associated with the address information start mark and nearest to pulses associated with the preceding region, are separated by five units of the pulse width of a single pulse having the second logic level,

and the address information start mark consists of one byte in total.

5. An optical disk apparatus for playing back data from an optical disk having a plurality of sectors constituting tracks formed spirally or concentrically, each of the plurality of sectors including:

a recording region for recording user data; and

a header region for recording address information including at least one address information start mark for synchronizing with a beginning of address information regarding the position of the sector, the address information start mark being represented by a sequence of pulses having a first logic level and pulses having a second logic level which is an inverse of the first logic level;

the optical disk detecting the address information start mark from the header region of the optical disk, and playing back the user data recorded in the recording region based on the address information obtained by synchronizing with the detected address information start mark,

wherein the address information start mark is detected based on a first detection criterion that a combination of pulse widths each defined in association with a nearest pair of bits having the first logic value is present in a pulse sequence, and also based on a second detection criterion that, when the logic level of the pulse sequence alternates between the first logic level and the second logic level in association with occurrence of each of a plurality of bits having the first logic value intermittently disposed among a plurality of bits having the second logic value, the logic levels of a number of pulses in the pulse sequence respectively coincide with the logic levels of the corresponding pulses constituting the combination of pulse widths.

6. An optical disk apparatus according to claim 5, wherein a pulse width of contiguous pulses having the first logic level is in a range of five to nine units of the pulse width of a single pulse having the first logic level, and a pulse width of contiguous pulses having the second logic level is nine units of the pulse width of a single pulse having the second logic level.

7. An optical disk apparatus according to claim 5, wherein whether the combination of pulse widths is present is determined with consideration also given to the logic levels of pulses associated with a region preceding the address information start mark.

8. An optical disk apparatus according to claim 6, wherein a pulse having the first logic level, associated with the preceding region and nearest to pulses associated with the address information start mark, and a pulse having the first logic level, associated with the address information start mark and nearest to pulses associated with the preceding region, are separated by five units of the pulse width of a single pulse having the second logic level,

and the address information start mark consists of one byte in total.