Optical disk drive for scanning an optical disk carrying a groove with a wobble
AssigneeLite-On It Corporation
InventorJan Bakx
Life of this patent
Estimating the term…
Abstract
An optical disk drive for scanning an optical disk having a wobbled groove and a land portion separating adjacent parts of the groove. The optical disk drive has a beam generator for generating a read beam and directing the read beam to the optical disk, a sensor for sensing a reflected beam produced by the optical disk upon receiving the read beam and for producing a sensor output signal with a sensor output signal amplitude, and an envelope analyzer to receive the sensor output signal from the sensor, to analyze an envelope (WS1e, WS2e) of the sensor output signal amplitude, and to derive from a variation of the envelope (WS1e, WS2e) as a function of time an indicator indicating whether the read beam is directed to the groove or to the land portion.
Claims26
An optical disk drive for scanning an optical disk comprising a substantially circular groove and a land portion separating adjacent parts of said groove, the groove being wobbled, comprising:
- a beam generator for generating a read beam and directing said read beam to said optical disk,
- a sensor for sensing a reflected beam produced by said optical disk upon receiving said read beam, and for producing a sensor output signal with a sensor output signal amplitude,
- an envelope analyzer arranged to:
- receive said sensor output signal from said sensor,
- analyze a first envelope of said sensor output signal amplitude,
- derive a modulation depth M of said first envelope as a variation of said first envelope as a function of time,
- an indicator for indicating whether said read beam is directed to said groove or to said land portion according to the modulation depth,
- wherein the modulation depth M is defined as:
- M=(Emax-Emin)/Emax
- wherein Emax is the maximum value of the envelope and Emin is the minimum value of the envelope.
An optical disk drive for scanning an optical disk comprising a substantially circular groove and a land portion separating adjacent parts of said groove, the groove being wobbled, comprising:
- a beam generator for generating a read beam and directing said read beam to said optical disk,
- a sensor for sensing a reflected beam produced by said optical disk upon receiving said read beam, and for producing a sensor output signal with a sensor output signal amplitude,
- an envelope analyzer arranged to:
- receive said sensor output signal from said sensor,
- analyze a first envelope of said sensor output signal amplitude,
- derive a standard deviation of said first envelope as a variation of said first envelope as a function of time,
- an indicator indicating whether said read beam is directed to said groove or to said land portion according to the standard deviation.
A method for determining an indicator for use with an optical disk drive, the optical disk drive arranged for scanning an optical disk comprising a substantially circular groove and a land portion separating adjacent parts of said groove, the groove being wobbled, and the optical disk drive comprising:
- a beam generator for generating a read beam and directing said read beam to said optical disk,
- a sensor for sensing a reflected beam produced by said optical disk upon receiving said read beam, and for producing a sensor output signal with a sensor output signal amplitude,
- wherein the method comprises:
- receiving said sensor output signal from said sensor,
- analyzing a first envelope of said sensor output signal amplitude,
- measuring a modulation depth M of said first envelope as a variation of said first envelope as a function of time, wherein the modulation depth M is defined as:
- M=(Emax-Emin)/Emax
- wherein Emax is the maximum value of the envelope and Emin is the minimum value of the envelope,
- indicating whether said read beam is directed to said groove or to said land portion according to the modulation depth by the indicator.
Dependencies are inferred from the claim text.