Method for accurate positioning of data marks and spaces on an optical disc

• US 6,654,331 B1
• Filed: 04/03/2000
• Issued: 11/25/2003
• Est. Priority Date: 04/03/2000
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Wilson, Carol J., Taussig, Carl P.
• Primary Examiner(s): Tran, Thang V.
• Assistant Examiner(s): Le, Kimlien
• Application Number:
  US09/541,812
• Time in Patent Office: 1,331 Days
• Field of Search: 369/47.28, 369/53.34, 369/53.36, 369/59.2, 369/59.11, 369/124.02, 369/47.53, 369/53.12, 369/53.13, 369/53.14, 369/53.15, 369/53.35, 369/59.12, 369/59.23, 369/275.3, 369/275.4
• US Class Current: 369/53.34
• CPC Class Codes: G11B 2220/216 Rewritable discs
• CPC Class Codes: G11B 2220/218 Write-once discs
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
• 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 7/0045 Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/24082 Meandering

Abstract

An optical disc has spatial features (notches, bumps, etc.) that intentionally distort the analog Read Data signal. For a mark or space that is centered on a spatial feature, the distortion does not affect the resulting binary Read Data signal. If an edge of a mark or space is near the spatial feature, the resulting binary Read Data signal is altered. For calibration, marks or spaces are written adjacent to spatial features, with a range of times for initiating the writes. The result is a range of write times that do not alter the binary Read Data signal. From these known times and spatial locations, it is known when a mark or space must be written to ensure accurate spatial placement.

Claims

1. A method of aligning a mark on a data track of an optical disc, comprising:

writing the mark, spatially near a spatial feature on the data track;

reading a signal from light illuminating the mark;

determining whether a time duration of the mark in the signal is correct; and

adjusting a time at which the mark is written, when the time duration of the mark in the signal is determined to be incorrect.

2. The method of claim 1, the step of determining whether the time duration of the mark in the signal is correct further comprising:

determining whether the mark results in a data error.

3. The method of claim 1, further comprising:

adjusting the time at which the mark is written, and repeating the steps of reading the signal and determining whether a time duration of the mark in the signal is correct, until a range of times at which the mark is written results in a correct time duration of the mark in the signal.

4. A method of aligning a space on a data track of an optical disc, comprising:

writing the space, spatially near a spatial feature on the data track;

reading a signal from light illuminating the space;

determining whether a time duration of the space in the signal is correct; and

adjusting a time at which the space is written, when the time duration of the space in the signal is determined to be incorrect.

5. The method of claim 4, the step of determining whether the time duration of the space in the signal is correct further comprising:

determining whether the space results in a data error.

6. The method of claim 4, further comprising:

adjusting the time at which the space is written, and repeating the steps of reading the signal and determining whether a time duration of the space in the signal is correct, until a range of times at which the space is written results in a correct time duration of the space in the signal.

7. A method of aligning marks relative to spatial wobble of a groove on an optical disc, comprising:

writing a test mark, spatially near a spatial feature on the spatial wobble, the spatial feature having a known spatial position relative to a zero-crossing of the spatial wobble;

reading a data signal from light illuminating the test mark;

reading a wobble signal from light illuminating the wobble;

determining whether a time duration of the test mark in the data signal is correct; and

using a time of writing the test mark, relative to a zero-crossing of the wobble signal, to write additional marks, when the time duration of the test mark in the data signal is correct.

8. The method of claim 7, the step of determining whether a time duration of the test mark in the data signal is correct further comprising:

determining whether the test mark results in a data error.

9. The method of claim 7, further comprising:

writing additional test marks, adjusting the time at which each test mark is written, and repeating the steps of reading the data signal and determining whether a time duration of each test mark in the signal is correct, until a range of times at which test marks are written results in a correct time duration of test marks in the signal.

10. A method of aligning spaces relative to spatial wobble of a groove on an optical disc, comprising:

writing a test space, spatially near a spatial feature on the spatial wobble, the spatial feature having a known spatial position relative to a zero-crossing of the spatial wobble;

reading a data signal from light illuminating the test space;

reading a wobble signal from light illuminating the wobble;

determining whether a time duration of the test space in the data signal is correct; and

using a time of writing the test space, relative to a zero-crossing of the wobble signal, to write additional spaces, when the time duration of the test space in the data signal is correct.

11. The method of claim 10, the step of determining whether a time duration of the test space in the data signal is correct further comprising:

determining whether the test space results in a data error.

12. The method of claim 10, further comprising:

writing additional test spaces, adjusting the time at which each test space is written, and repeating the steps of reading the data signal and determining whether a time duration of each test space in the signal is correct, until a range of times at which test spaces are written results in a correct time duration of test spaces in the signal.

13. A method of verifying spatial accuracy of marks relative to spatial wobble of a groove on an optical disc, comprising:

writing a test mark, spatially near a spatial feature on the spatial wobble, the spatial feature having a known spatial position relative to a zero-crossing of the spatial wobble;

reading a data signal from light illuminating the test mark;

determining whether a time duration of the test mark in the data signal is correct; and

determining that the test mark is spatially accurate when the time duration of the test mark in the data signal is correct.

14. The method of claim 13, the step of determining whether a time duration of the test mark in the data signal is correct further comprising:

determining whether the test mark results in a data error.

15. A method of verifying spatial accuracy of marks relative to spatial wobble of a groove on an optical disc, comprising:

writing a test space, spatially near a spatial feature on the spatial wobble, the spatial feature having a known spatial position relative to a zero-crossing of the spatial wobble;

reading a data signal from light illuminating the test space;

determining whether a time duration of the test space in the data signal is correct; and

determining that the test space is spatially accurate when the time duration of the test space in the data signal is correct.

16. The method of claim 15, the step of determining whether a time duration of the test space in the data signal is correct further comprising:

determining whether the test space results in a data error.