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. 24, 1989
Filed:
Sep. 01, 1987
George R Wisner, Deep River, CT (US);
Otis Elevator Company, Farmington, CT (US);
Abstract
An arrangement for detecting the passage of living beings into and out of a surveillance region includes optics which concentrate thermal radiation energy from the surveillance region into a detection zone where an active area of a pyroelectric detector is situated and converts the thermal radiation energy received thereby into an electrical signal. An evaluating device evaluates the electrical signal of the detector to provide an indication of either the entry of a living being from the outside into, or the exit of a person from, the surveillance region from a change in the total thermal radiation energy received by the active area from the surveillance region. The optics may incorporate a mask which prevents thermal radiation from the outside of the surveillance region from reaching the active area of the detector. The mask includes a marginal portion which peripherally bounds an opening for the passage of the thermal radiation energy from the surveillance region to the detection zone and which may include at least one serration at the opening for controlling the timing of the electrical signal caused by entry of a living being into an area of the surveillance region corresponding to the serration relative to those caused by entry of a living being into the remainder of the surveillance region.