Optical arrangement for a passive infrared motion detector

US4271359A · kind A · utility

Assignee

• Heimann GmbH · DE

Inventors

• Thomas Herwig · Eltville am Rhein, DE
• Gerhard Doenges · Nastätten, DE

Key dates

• Filing date: Apr 7, 1980
• Grant date: Jun 2, 1981
• Expiry date: Apr 7, 2000

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S250/01
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical arrangement for use with an infrared detector characterized by a concave mirror surrounding the infrared detector, a body having a plane reflecting surface extending perpendicular to the axis of the detector, which surface faces the detector and the conical concave mirror, and having a conical reflecting surface extending from the plane surface, and at least one planar directional mirror pivotably mounted for reflecting infrared radiation at the conical reflecting surface. The arrangement can be used to monitor a space and if used with a second arrangement, whose directional mirrors are arranged to provide new sensing curtains adjacent the curtains of the first detector, the arrangement can determine the direction of movement of the object passing through the space.