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. 25, 1986
Filed:
Dec. 11, 1984
John K Guscott, Lynnfield, MA (US);
American District Telegraph Company, New York, NY (US);
Abstract
The ceiling mountable passive infrared intrusion detection system of the present invention includes a focusing mirror having an optical axis, and a composite field-forming mirror cooperative with the focusing mirror for providing both a plurality of vertical curtains and a plurality of uniform detection sensitivity finger beams defining fields of view in selected azimuthally spaced relation through which an intruder must pass when in motion about the floor of a protected facility. The composite field-forming mirror includes first and second pluralities of selectively-twisted cylindrical facets defining longitudinal axes that individually intersect the optical axis of the focusing mirror at preselected different non-zero acute angles and provide corresponding ones of the selectively azimuthally spaced fields of view of the vertical curtains. The composite field-forming mirror includes a third plurality of planar facets having normals that are orthogonal to corresponding ones of the longitudinal axes of the selectively-twisted cylindrical facets to provide the fields of view of the finger beams. The composite field-forming mirror defines an effectively continuous optical aperture.