Land/groove detecting method and apparatus for an optical disk
US5909416A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1997 |
| Grant date | Jun 1, 1999 |
| Priority date | — |
| Expiry date | Nov 17, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0943
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to a technique to detect lands and grooves formed on an optical disk, and is intended to provide a land/groove detecting apparatus capable of steadily obtaining track detection signals and land/groove detection signals. According to the invention, +1-, 0- and -1-order light beams obtained from a three-beam type optical head are received by a 6-divided optical sensor, and the 0-order beam is detected by optical sensor elements a, b, c and d of a 4-divided optical sensor while the +1- and -1-order beams are detected by two optical sensor elements e and f, respectively, on the two sides of the 4-divided optical sensor. The output signals of the optical sensor elements a, b, c, d, e and f are denoted by A, B, C, D, E and F, respectively. As a tracking error signal and a land/groove detection signal are calculated by equations TE=E-F and LG=(2.times.(A+B+C+D)-(E+F)), the land/groove detection signal LG is held at a zero cross point of the tracking error signal TE, and whether getting on a track has taken place on a land or on a groove is determined according to a polarity of the held land/groove detection signal LG, stable tracking error signals and land/groove det…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.