Optical system for ceiling mounted passive infrared sensor
First Claim
1. A ceiling mountable passive infrared intrusion system having a combination mirror assembly for detecting an intruder both when present on the floor of an area to be protected and when present between the ceiling and the floor of the area to be protected, comprising:
- a first mirror having an optical axis for focusing radiation incident thereon at a point focus along its optical axis;
a mirror sub-assembly including a second mirror for providing a curtain-like first field of view that has a nominal range, a comparatively narrow azimuthal extent, and a comparatively wide elevational extent, and cooperative with the first mirror for directing the radiation present in the first field of view onto the point focus;
said mirror sub-assembly including a third mirror for providing a disc-like second field of view that is generally transverse the first field of view that has a nominal range, a comparatively narrow elevational extent, and a comparatively wide azimuthal extent, and cooperative with the first mirror for directing the radiation present in the second field of view onto the point focus; and
an infrared detector positioned at the point focus of the first mirror along the optical axis thereof and operative in response to the radiation focused thereat to provide an electrical signal representative of intruder presence.
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Accused Products
Abstract
A ceiling mountable passive infrared intrusion detection system is disclosed having a mirror assembly providing a first protective curtain which is relatively narrow in the horizontal plane and which substantially encompasses the vertical space of a protected facility, and providing a second protective curtain which is relatively narrow in the vertical plane and which substantially encompasses 360° of horizontal space of a protected facility. A temperature stabilized and shock insensitive infrared detector is disposed along the optical axis and at the focal point of the system to provide electrical signals in response to received radiation from the field of view of the protective curtains. The electrical signals are electronically processed to provide an output indication of intruder presence when in motion about both the floor area and the space between the floor area and the ceiling of a protected facility.
32 Citations
15 Claims
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1. A ceiling mountable passive infrared intrusion system having a combination mirror assembly for detecting an intruder both when present on the floor of an area to be protected and when present between the ceiling and the floor of the area to be protected, comprising:
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a first mirror having an optical axis for focusing radiation incident thereon at a point focus along its optical axis; a mirror sub-assembly including a second mirror for providing a curtain-like first field of view that has a nominal range, a comparatively narrow azimuthal extent, and a comparatively wide elevational extent, and cooperative with the first mirror for directing the radiation present in the first field of view onto the point focus; said mirror sub-assembly including a third mirror for providing a disc-like second field of view that is generally transverse the first field of view that has a nominal range, a comparatively narrow elevational extent, and a comparatively wide azimuthal extent, and cooperative with the first mirror for directing the radiation present in the second field of view onto the point focus; and an infrared detector positioned at the point focus of the first mirror along the optical axis thereof and operative in response to the radiation focused thereat to provide an electrical signal representative of intruder presence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification