Patent EP0219954A1 successfully refreshed from Google Patents.
EP0219954A1
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An infra-red detector system
Assignee: MAXIMAL ELECTRICAL ENGINEERS Ltd
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Filing: 1986-09-03
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Granted: —
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Expires: 2006-09-03
Abstract
Abstract An infra-red intruder detection apparatus has an optical system comprising a Fresnel plate (7) and an infra-red sensor (5) positioned at the focus of the Fresnel plate. An optical path extending from the Fresnel plate to the infra-red sensor is bounded on either side by first and second mirrors (2, 3) diverging from the sensor towards the Fresnel plate to thereby provide a first fan of field of view for the sensor. A third mirror (4) is preferably disposed above the optical path to thereby provide a second fan of field of view for the sensor below the first said fan.
Inventors
- 👤 John T. Grant
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 01:08
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19; G08B13/193
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
83 words
An infra-red detector system comprising an infra-red sensor connected in a detector circuit and an optical system including reflectors arranged to provide fields of view for the sensor diverging in a fan-like manner, characterised in that the optical system includes a pair of upright plane mirrors (2,3) positioned in front of the sensor (5) and diverging at a small angle so as to produce a plurality of virtual images of the sensor (5), and a focussing lens (1) in front of the mirrors.
Claim 2
Dependent Claim
83 words
An infra-red detector system comprising an infra-red sensor connected in a detector circuit and an optical system including reflectors arranged to provide fields of view for the sensor diverging in a fan-like manner, characterised in that the optical system includes a pair of upright plane mirrors (2,3) positioned in front of the sensor (5) and diverging at a small angle so as to produce a plurality of virtual images of the sensor (5), and a focussing lens (1) in front of the mirrors.
Claim 3
Dependent Claim
42 words
An infra-red detector system according to claim 1 including a further plane mirror (4) positioned in front of an above the sensor (5) and inclined at an angle to the horizontal so as to produce a lower fan of fields of view.
Claim 4
Dependent Claim
25 words
An infra-red detector system according to claim 1 or claim 2 in which the lens is a Fresnel plate bearing a plurality of lens segments.
Claim 5
Dependent Claim
23 words
An infra-red detector system according to claim 3 in which the optic axis of at least one lens segment lies outside the segment.
Claim 6
Dependent Claim
45 words
6 . An infra-red intruder detection apparatus comprising an infrared sensor for connection in a detector circuit characterised by a lens and first and second plane reflectors arranged so as to provide the sensor with a plurality of fields of view focussed by said lens.
Claim 7
Dependent Claim
45 words
6 . An infra-red intruder detection apparatus comprising an infrared sensor for connection in a detector circuit characterised by a lens and first and second plane reflectors arranged so as to provide the sensor with a plurality of fields of view focussed by said lens.
Claim 8
Dependent Claim
71 words
An infra-red intruder detection apparatus according to claim 5 characterised in that the lens is a Fresnel lens defining an optical path extending from the Fresnel lens to the sensor, and said first and second reflectors are disposed on either side of the optical path diverging from the sensor towards the Fresnel lens so as to provide fields of view focussed direct.from the lens and via the first and second reflectors.
Claim 9
Dependent Claim
30 words
An infra-red intruder detection apparatus according to claim 6 characterised by a third plane reflector discposed above the optical path to provide further fields of view via the third reflector.
References Cited (Backward Citations)
US3703718A
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US3703718B1
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US4087688A
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