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. 07, 1989
Filed:
Jun. 24, 1988
Korry Electronics Company, Seattle, WA (US);
Abstract
A switch mechanism (11) comprising a red LED light source (13), a filter assembly (15) and a photodetector assembly (17) is disclosed. The photodetector assembly (17) includes two filtered photodetectors (33 and 35) that are aligned with the light source (13) either directly or via a light canal (19). The filtered photodetectors (33 and 35) are designed to detect light in different narrow wavelength bands lying within the band of energy produced by the light source (13). The filter assembly (15) includes a two-position movable element (23) located between the light source (13) and the photodetector assembly (17). The movable element (23) includes two sections (25 and 27) having different light-passing abilities. In one of the movable element positions one section (25) is located between the light source and both filtered photodetectors and in the other movable element position the other section (27) is located therebetween. Preferably, one section (25) is a thin slab of transparent material and the other section (27) is a thin slab of filter material. The transmittance of the filter dye slab (27) is such that the ratio of the energy detected by the filtered photodetectors (33 and 35) when the filter dye slab (27) is located between the light source (13) and the filtered photodetectors (33 and 35) is different than the ratio of the energy detected when the transparent slab (25) is located between the light source (13) and the filtered photodetectors (33 and 35). Thus, the difference in ratios determines the position of the movable element (23).