The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 24, 1995
Filed:
Feb. 14, 1994
David Blau, Cupertino, CA (US);
Scientific Technologies Incorporated, Hayward, CA (US);
Abstract
An optical sensing array and method of operation for controlling the acceptance angle of light beams which are iteratively strobed in side-by-side channels between light transmitters and light receivers. In one embodiment, the light beams in at least a pair of channels are directed along axes which are intentionally mispointed or squinted. A control circuit measures the amplitudes of signals produced responsive to light being received by the light receivers and compares the ratio of those amplitudes to the ratio of predetermined high and low amplitude values which provide a threshold window. When the ratio of the signal amplitudes exceeds the ratio of the window threshold values, an output signal is produced indicative of an unsafe operating condition. The control circuit further maintains the gain of the signals from the light receivers to stay within the range of the predetermined window threshold values. In another embodiment, the light transmitter and receiver in at least one channel are offset in opposite directions from an optical axis of the channel for producing a narrow beam angle.