Passive infra-red detectors
First Claim
1. A radiation detector comprising:
- a housing defining a radiation receiving slit aperture; and
an optical system disposed within said housing defining a field-of view and including;
at least one radiation reflecting surface arranged to receive radiation passing through said radiation receiving slit aperture and to focus said radiation on a radiation sensor disposed in said housing, said at least one radiation reflecting surface being defined by a collection of curves disposed along an ellipse, said ellipse having a first focus and a second focus along a principal axis thereof, said at least one radiation reflecting surface defining a slit axis which passes through said second focus and said slit aperture, each of said curves being defined by the intersection at a point on the ellipse, of a slit axis plane which includes the slit axis and a focusing surface whose focus is at said first focus and which has an axis of symmetry which is parallel to said slit axis plane.
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0 Petitions
Accused Products
Abstract
A passive infra-red detector including at least three sub-detectors, each sub-detector being operative to receive infra-red radiation from a corresponding one of at least three sub fields-of-view, each sub field-of-view being exclusively defined by an optical element which does not define any other sub field of view, the sub fields-of-view being angled with respect to each other, adjacent ones of the sub fields-of-view being separated by a gap of no more than 30 degrees and at least one of the sub fields-of-view having at least one of the following characteristics: extending over no more then 45 degrees in azimuth; and including not more than three azimuthally distributed detection zones, and signal processing circuitry, operative to receive output signals from the sub detectors and to provide a motion detection output.
72 Citations
73 Claims
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1. A radiation detector comprising:
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a housing defining a radiation receiving slit aperture; and an optical system disposed within said housing defining a field-of view and including; at least one radiation reflecting surface arranged to receive radiation passing through said radiation receiving slit aperture and to focus said radiation on a radiation sensor disposed in said housing, said at least one radiation reflecting surface being defined by a collection of curves disposed along an ellipse, said ellipse having a first focus and a second focus along a principal axis thereof, said at least one radiation reflecting surface defining a slit axis which passes through said second focus and said slit aperture, each of said curves being defined by the intersection at a point on the ellipse, of a slit axis plane which includes the slit axis and a focusing surface whose focus is at said first focus and which has an axis of symmetry which is parallel to said slit axis plane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A radiation detector comprising:
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a housing defining a radiation receiving slit aperture; and an optical system disposed within said housing defining a field-of-view and including; at least one radiation reflecting surface arranged to receive radiation passing through said radiation receiving slit aperture and to focus said radiation on a radiation sensor disposed in said housing, said at least one radiation reflecting surface being defined by a collection of curves disposed along at least one ellipse, said at least one ellipse lying in the same plane and having a common first focus and a common second focus along a principal common axis thereof, said at least one radiation reflecting surface defining a slit axis which passes through said second focus and said slit aperture, each of said curves being defined by the intersection at a point on the at least one ellipse, of a slit axis plane which includes the slit axis and a focusing surface whose focus is at said first common focus and which has an axis of symmetry which is parallel to said slit axis plane. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A radiation detector comprising:
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a housing defining a radiation receiving slit aperture; and an optical system disposed within said housing defining a field-of-view and including; at least one radiation reflecting surface arranged to receive radiation passing through said radiation receiving slit aperture and to focus said radiation on a radiation sensor disposed in said housing, said at least one radiation reflecting surface comprising at least one radiation reflecting surface segment curved in at least two mutually orthogonal planes, each of said at least one radiation reflection surface segment being defined by an array of curves which intersect an ellipse having a first focus at a first focus at a first common focus point and a second focus in the vicinity of said slit aperture, each of said array of curves being focused at said first focus of said ellipse. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A radiation detector comprising:
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a housing defining an elongate radiation receiving slit aperture through which extend a first plurality of slit axes, each of said plurality of slit axes passing through a common first focus of a second plurality of ellipses having a common second focus, said common first focus and said common second focus lying along a common primary axis of symmetry; a radiation sensor disposed within said housing; and a radiation reflecting surface arranged to receive radiation passing through said elongate radiation receiving slit aperture and to focus said radiation on said radiation sensor, said radiation reflecting surface comprising a first plurality of radiation reflecting surface segments, each of said first plurality of radiation reflecting surface segments including a segment surface curved in at least two mutually orthogonal planes, each said segment surface including a portion of at least one of said second plurality of ellipses and being defined by a continuous array of curves which join said portion of said at least one of said second plurality of ellipses, said continuous array of curves being focused at said common second focus of said second plurality of ellipses. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
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Specification