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:
Jan. 21, 1992
Filed:
Jul. 11, 1990
George W Rhyne, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An index of refraction sensor having a photo detector array with variable sized elements is provided. The photo diode array comprises a plurality of diodes with varying area. The diodes farthest from a light emitting diode having a larger area than those closer to the light emitting diode. Preferably the diode area is designed so that each of the diodes produces approximately the same current output when exposed to light from the LED. Each diode in the photo diode array is sequentially powered and the photo diode outputs are summed together. A power input from a first diode in the array is coupled to a start input of a time measurement circuit. The summed output of the photo diode array is coupled to a stop input of the time measurement circuit. Elapsed time measured by the time measurement circuit is thus a function of reflected light edge location, and therefore a function of index of refraction of the fuel mixture.