Passive type crime-preventing infrared sensor provided with a mechanism of monitoring an obstruction for the visual field
First Claim
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1. A passive-type, crime-preventing infrared sensor, comprising:
- first detecting means for detecting infrared radiation from an object in a visual field to be monitored;
a first electrical alarm circuit means for providing an alarm in response to detection of a signal output from said first detecting means;
second detecting means for detecting infrared radiation from an object approaching said first detecting means independently of said first detecting means, thereby detecting an obstruction of said first detecting means; and
a second alarm circuit means for providing an alarm response to detection of a signal from said second detecting means, said second alarm circuit being electrically isolated from said first alarm circuit.
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Abstract
The disclosure relates to a crime-preventing infrared sensor of a passive type in which the infrared detecting element 6 detects the energy of infrared rays radiated from an object in a predetermined visual field to be monitored and an alarm is given in response to a detection signal outputted from the infrared detecting element. The crime-preventing infrared sensor comprises an infrared detector 7 for detecting a human body or any other object approaching the sensor itself independently of an object-detecting function in a visual field, whereby the obstruction in the visual field of the object-detecting function is prevented.
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Citations
3 Claims
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1. A passive-type, crime-preventing infrared sensor, comprising:
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first detecting means for detecting infrared radiation from an object in a visual field to be monitored; a first electrical alarm circuit means for providing an alarm in response to detection of a signal output from said first detecting means; second detecting means for detecting infrared radiation from an object approaching said first detecting means independently of said first detecting means, thereby detecting an obstruction of said first detecting means; and a second alarm circuit means for providing an alarm response to detection of a signal from said second detecting means, said second alarm circuit being electrically isolated from said first alarm circuit. - View Dependent Claims (2, 3)
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Specification