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:
Nov. 16, 1993
Filed:
May. 04, 1992
John L Rink, San Francisco, CA (US);
Diolase Corporation, Berkeley, CA (US);
Abstract
A proximity sensor apparatus for use with a laser diode device utilizes the photodiode mounted in the housing of the laser diode, and includes an electronic circuit coupled to the photodiode to monitor the output of the photodiode. When an object is closely adjacent to the output window of the laser diode, reflected light from the laser diode is transmitted retrograde through the output window and is received by the photodiode within the housing. The circuit of the invention establishes a threshold level for the photodiode current, determines the proximity of the reflecting object and permits (or prevents) operation of the laser diode. The circuit also includes a sampling timer to operate the laser diode for a very brief period (on the order of microseconds) each second, to ascertain if a target object is proximate to the laser diode output. The circuit is set to prevent laser operation, and operates the laser diode to emit a brief test pulse and determine the level of reflected laser light. If the reflected light level indicates that a target object is proximate, the circuit will switch on the laser diode, while continuing to monitor the photodiode current. If the reflected light level indicates that no target object is proximate, the laser diode will switch off, and the circuit will emit another brief test pulse after a delay of approximately one second. This process is reiterated.