Importance

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Abstract

An infrared radiation detector device, for example, for an intruder alarm, comprises two dual detectors. Each dual detector constitutes a separate detection channel and has two pyroelectric detector elements. The detector elements are formed from pyroelectric material with electrodes on opposite surfaces. The detector elements of each dual detector are spaced apart from one another and connected in a circuit differentially to cancel out the effects of temperature changes common to both elements. One detector element of one dual detector is interdigitated with a respective detector element of the other dual detector, thus enabling the two dual detectors to respond to incoming radiation and provide outputs at, or very nearly at, the same time. In this way, when used in an intruder alarm, the risk of false triggering is reduced. The other detector elements of the dual detectors may similarly also be interdigitated.

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First Claim