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US 5,517,012 AGranted
Optical scanner
AssigneeAT&T Corp.
InventorsRobert A. Boie, Gabriel L. Miller
Life of this patent
Estimating the term…
Abstract
A circuit that prevents optical screening systems from being pinned in an inoperative state under certain light conditions. The invention accomplishes this by using a circuit comprising a photodetector for converting scattered light from a visual code (e.g., universal product code) into current and a current limiting circuit coupled to the photodetector for limiting the current capable of passing through the photodetector.
Claims15
An optical scanning circuit for generating a current representing a scattered light pattern, the optical scanning circuit comprising:
- (a) a photodetector for converting the scattered light pattern into current;
- and
- (b) a current limiting circuit coupled to the photodetector for enhancing the optical scanning circuit's ability to recover from an optical overload.
An optical scanning system comprising:
- (a) a light source;
- (b) means for directing the light source;
- (c) means for processing a scattered light pattern, the means for processing comprising:
- (1) a photodetector for generating a current representing the scattered light pattern;
- (2) means for biasing the photodetector;
- (3) an amplifier coupled to the photodetector;
- and
- (4) a current limiting circuit coupled to the photodetector for enhancing the optical scanning circuit's ability to recover from an optical overload;
- and
- (d) means for outputting a signal representing the scattered light pattern.
7 more elements
Dependencies are inferred from the claim text.