Piezoelectric dynamic quantity sensor

Abstract

Abstract PURPOSE:To obtain a high-accuracy detection output from which the influence of pyroelectricity is removed by moving a dynamic quantity detection body for acceleration, etc., periodically and varying the detection output. CONSTITUTION:Piezoelectric elements 2 and 3 send out mutually opposite-phase detection signals S1 and S2 in response to the same stress variation. A subtracting circuit 32 subtracts a detection signal S4 from S3 after impedance conversion 31 and 30 and supplies the subtraction output S5 to a by-pass filter 33. Here, the cutoff frequency of a filter 33 is so selected as to pass a frequency component accompanying the rotation of a detection body A, and then an output S6 is free from the influence of pyroelectricity. This output S6 is supplied to a sample holding circuit 34. The circuit 34 is supplied with detection signals phi1 and phi2 as sampling signals from photodetecting elements 29a and 29b. Sample holding outputs S7 and S8 by the signals phi1 and phi2 are passed through LPFs 35 and 36 to remove noise components.

Inventors

• 👤 Akira Asaoka
• 👤 昭 浅岡

Bibliographic Details