System for separating an optical signal from ambient light

Details System for separating an optical signal from ambient light System for separating an optical signal from ambient light

1979-12-06

1981-12-01

Nelms, David C.

Radiant energy

Photocells; circuits and apparatus

Optical or pre-photocell system

455619, C01J 334

Patent

active

043038557

ABSTRACT:
An arrangement for separating disturbing ambient light from an optical data signal, comprising an interference filter (1), the passband of which matches the wavelength of the optical data signal, and further comprising two photodiodes which are so arranged that one photodiode receives the light (I.sub.S, I.sub.AT) transmitted through the interference filter, and that the other receives the reflected light (I.sub.AR). Adjusting means, e.g., in the form of a settable aperture (4) or an additional simple filter (5) are provided for adjusting the transmitted and reflected portions of the ambient light to each other. Output signal (S1, S2) of both photodiodes are subtracted from each other in compensation circuitry (6). This results in compensation of the ambient light components so that at the output a signal (SR) is available which depends only on the actual data signal (I.sub.S).

REFERENCES:
patent: 3456997 (1969-07-01), Stites et al.
patent: 3821550 (1974-06-01), Priest
patent: 4057352 (1977-11-01), Babb
patent: 4127773 (1978-11-01), West
patent: 4228349 (1980-10-01), Ettenberg et al.
"Spectrophotometric Noise Cancellation", by Pillus et al., IBM Tech. Disc. Bull., vol. 19, No. 6, Nov. 1976, pp. 2185-2186.
"Ambient-Light Rejection for Laser Scanners", by Soderstrom, IBM Tech. Disc. Bull., vol. 17, No. 12, May 1975, pp. 3682-3683.
"Wireless Connection Between a Controller and a Plurality of Terminals", by Closs et al., IBM Tech. Disc. Bull., vol. 20, No. 7, Dec. 1977, p. 2843.
"Infrared Detection System", by Boynton et al., IBM Tech. Disc. Bull., vol. 15, No. 5, Oct. 1972, pp. 1483-1484.

Affiliated with

Also associated with

Rating

System for separating an optical signal from ambient light does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with System for separating an optical signal from ambient light, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for separating an optical signal from ambient light will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1298351