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. 23, 1984
Filed:
May. 17, 1982
Hermann Zierhut, Munich, DE;
Richard Hirschmann Radiotechnisches Werk, Esslingen am Neckar, DE;
Abstract
A motion detector responsive for infrared radiation, e.g. to use in burglar-alarm installations, comprises an elongate frustopyramidal box with an entrance opening at one end, a concave mirror at the opposite end and four flat, internally reflecting longitudinal walls, two of them converging toward the entrance end on opposite sides of a plane of symmetry with which they include an angle between about 8.degree. and 15.degree.. A pyroelectric radiation sensor near the entrance end, lying in the vicinity of the focal point of the concave mirror, is disposed for illumination by beams of parallel rays in a limited number of fields of view; these beams approach the entrance end at different azimuthal angles, included with the preferably vertical plane of symmetry, but occupy closely adjoining regions inside the box. A planar deflector at the entrance end, bisected by the plane of symmetry, also establishes a limited number of elevational angles for the beams focused upon the radiation sensor.