Patent · US Expired

Optical scanning system for a sinusoidal data track

US5247507A · kind A · utility

13Cited by

1References

1Claims

0Family size

Assignee

Deutsche Thomson-Brandt GmbH · DE

Inventors

Yasuaki Morimoto · Villingen-Schwenningen, DE
Friedhelm Zucker · Mönchweiler, DE
Christian Buchler · Villingen-Schwenningen, DE

Key dates

Filing date	Jan 16, 1992
Grant date	Sep 21, 1993
Priority date	—
Expiry date	Jan 16, 2012

Classification

Technology area (CPC G)Physics
CPC primaryG11B7/24082
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

An optical scanning system for a compact disc having a sinusoidal data track radially meandering, at a selected frequency, about the axis of rotation of the disc includes a first laser beam for reading data from the data track. A +1 level laser beam and a -1 level laser beam respectively track the opposite edges of the data track and generate a tracking error signal. The +1 level laser beam and the -1 level laser beam are separated, with respect to the disc, by a distance equal to an odd integer multiple of one half the wavelength corresponding to the selected frequency. The +1 and -1 laser beams are not modulated by the sinusoidal data track and standard tracking circuitry can be used to track the data track.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.