Patent · US Expired

Optical memory with injection laser as light source and detector

US4241423A · kind A · utility

26Cited by

6References

7Claims

0Family size

Assignee

RCA Corporation · US

Inventors

William J. Burke · Princeton Junction, US
Henry Kressel · Elizabeth, US
Michael Ettenberg · Freehold, US

Key dates

Filing date	Dec 22, 1978
Grant date	Dec 23, 1980
Priority date	—
Expiry date	Dec 22, 1998

Classification

Technology area (CPC G)Physics
CPC primaryG11C13/048
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

In an optical memory device, such as an optical video disk, an injection laser is used as the source of the light, as the detector of the light reflected from the memory element and as the detector for controlling the proper focus of the light on the memory element. The light reflected from the memory element is fed back into the injection laser and variations in certain characteristics of the injection laser, such as the optical output at constant current, the electrical current through the laser at constant voltage and the voltage drop across the laser at constant current, are used to read the memory device and to maintain the focus.

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