| 摘要 |
<p>PURPOSE:To prevent a malfunction caused by extrinsic noises and intrinsic noises by forming plural infrared absorption electrodes on the surface of a pyroelectric material where polarization processing is wholly performed in the same direction, forming a common electrode on the back surface of the pyroelectric material and connecting it to a grounding point. CONSTITUTION:The infrared absorption electrodes 2a and 2b are formed on the surface of a substrate 1 consisting of the pyroelectric material to which the polarization processing is wholly performed in the same direction. The gate terminals of FETs for converting impedance 4a and 4b are respectively connected to respective pyroelectric elements 3a and 3b which take the electrodes 2a and 2b on the surface of the substrate as output terminals. Output signals S1 and S2 are respectively fetched from the respective source terminals of the FETs 4a and 4b. Only when the two detection signals S1 and S2 have a specified time difference, a microcomputer supplies the signal to an output circuit. Therefore, a popcorn noise which appears only in the output of one of the FETs 4a and 4b is interrupted in the microcomputer 7 and the mulfunction is prevented.</p> |
