Patent · US Active

Compatible optical recording medium

US8213289B2 · kind B2 · utility

0Cited by

14References

5Claims

0Family size

Assignee

Thomson Licensing · FR

Inventors

Joachim Knittel · Tuttlingen, DE
Hartmut Richter · Villingen-Schwenningen, DE
Alan Bruce Hamersley · Orange, US

Key dates

Filing date	Sep 24, 2007
Grant date	Jul 3, 2012
Priority date	—
Expiry date	Jul 17, 2028

Classification

Technology area (CPC G)Physics
CPC primaryG11B2007/24314
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

The optical recording medium has a recording layer sensitive for recording at a first wavelength and sensitive for reading at a second wavelength, the recording layer having a groove structure, wherein at the first wavelength the groove structure has a diffraction efficiency into a first diffraction order sufficiently large to generate a push-pull signal, and at the second wavelength it has a diffraction efficiency into a first diffraction order close to zero. The optical pickup for recording on an optical recording medium intended to be read with a second wavelength and a second numerical aperture is characterized in that it has a light source for generating a light beam at a first wavelength and a numerical aperture given by the second numerical aperture multiplied with a ration of the first wavelength and the second wavelength.

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