Patent · US Expired

Laser-optical writing and reading process using a thermally alterable reading layer containing liquid-crystalline compound

US5097463A · kind A · utility

9Cited by

10References

17Claims

0Family size

Assignee

BASF SE

Inventors

Gerhard Wagenblast · Wachenheim, DE
Karl-Heinz Etzbach · Bischofswerda, DE
Bernd Hisgen · Schifferstadt, DE

Key dates

Filing date	Feb 10, 1988
Grant date	Mar 17, 1992
Priority date	—
Expiry date	Feb 10, 2008

Classification

Technology area (CPC G)Physics
CPC primaryG11B7/24
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A laser-optical write and read process whereby a thermally alterable recording layer which contains liquid-crystalline compounds in homogeneous planar orientation and forms part of a multilayer, sheet-like recording material is written by means of a write laser beam with analogue or digital data in the form of thermally altered areas, whereafter the written data are read by means of a read laser beam, including: analyzing the light transmitted or reflected by the recording material, and reading the data by determining the polarization-optical contrast between the thermally altered and the unaltered areas and/or utilizing for this purpose the interference of the light rays which form from the laser lightwaves in a Gaussian intensity distribution owing to the different phase velocities of the light in the center of thermally altered areas on the one hand and their thermally unaltered surroundings on the other.

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