Intruder detection system
First Claim
1. An improved Intruder Detection System for optically monitoring an area and producing an alarm signal only in response to motion of an intruder across the monitored area, including:
- (a) A sensor optically responsive to infrared radiation of an intruder, the sensor having at least a pair of discrete sensing areas each producing an electrical output in response to infrared radiation;
(b) Optical means directing infrared radiation from only the monitored area onto the discrete sensing areas of the sensor, radiation from only a portion of the monitored area being directed onto each sensor area, whereby movement of an intruder across the monitored area causes one then the other of the sensor areas of the pair to produce an electrical output;
(c) Means to direct visible light from one sensor area to another sensor area, said means including a V-shaped reflector, a planar member substantially transparent to visible light generally bisecting the V-shaped reflector, the sensor areas including sensor elements positioned on both face surfaces of the planar member located relative to one another such that visible light striking one sensor element passes through the planar member then strikes the other sensor element; and
(d) Electronic means for accepting and analyzing the electrical outputs of the sensor areas and producing an alarm signal only in response to the occurrence of an electrical output of one sensor area then of the other sensor area of a pair within a predetermined period of time.
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Accused Products
Abstract
The improved intruder detection system of the present invention, because of its sensor, optical, and electronic systems, is uniquely capable of responding only to radiation from an intruder to signal an alarm. To achieve this, the sensor and optical systems are designed and cooperate to optically reject and balance-out extraneous, nonintruder-related radiation. In addition, the electronic system detects and rejects nonintruder-related inputs by recognizing certain uniquely intruder-related characteristics of the sensor signals, and to only signal an alarm in response to inputs evidencing such characteristics. Preferably the system is designed to reliably sense the presence of an intruder in multiple zones, to be economical to manufacture, easy to install, to be battery-powered and of a long life.
58 Citations
11 Claims
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1. An improved Intruder Detection System for optically monitoring an area and producing an alarm signal only in response to motion of an intruder across the monitored area, including:
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(a) A sensor optically responsive to infrared radiation of an intruder, the sensor having at least a pair of discrete sensing areas each producing an electrical output in response to infrared radiation; (b) Optical means directing infrared radiation from only the monitored area onto the discrete sensing areas of the sensor, radiation from only a portion of the monitored area being directed onto each sensor area, whereby movement of an intruder across the monitored area causes one then the other of the sensor areas of the pair to produce an electrical output; (c) Means to direct visible light from one sensor area to another sensor area, said means including a V-shaped reflector, a planar member substantially transparent to visible light generally bisecting the V-shaped reflector, the sensor areas including sensor elements positioned on both face surfaces of the planar member located relative to one another such that visible light striking one sensor element passes through the planar member then strikes the other sensor element; and (d) Electronic means for accepting and analyzing the electrical outputs of the sensor areas and producing an alarm signal only in response to the occurrence of an electrical output of one sensor area then of the other sensor area of a pair within a predetermined period of time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electrical system for an improved intruder detection system having at least two sensors electrically responsive to radiation, the electronic system including:
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at least two separate electronic channel means for responding respectively to the electrical outputs of the two sensors, the channel means each being responsive to the presence of the electrical output of the sensor to produce an output only in response to an input above an initial threshold level; means to automatically adjust the sensitivity of at least one channel in response to the output of the other channel to cause said one channel to produce an output in response to an input above a threshold level lower than said initial threshold level; means for analyzing the output of the respective channel means and producing an alarm signal only in response to the occurrence of said channel output within a predetermined period of time; a battery power source connected to power the respective electrical means; means to reset the system following an alarm signal output; and means responsive to a decrease of the battery voltage below a certain level to prevent the system from being reset by said reset means. - View Dependent Claims (10, 11)
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Specification