Title:
TEMPERATURE DETECTING CIRCUIT AND ELEMENT
Document Type and Number:
Japanese Patent JPH03255924
Kind Code:
A
Abstract:
PURPOSE:To handle a wide temperature range and to enable high-accuracy, high- stability temperature control by providing a temperature detecting element which uses a piezoelectric body, a temperature detecting circuit, and a temperature variation detecting circuit. CONSTITUTION:The temperature detecting element 10 has electrodes 12 and 13 formed on the surface of a crystal piece 11 which is so cut that the temperature dependency of frequency characteristics is large and the pyroelectric performance is large. The object 6 of temperature control is coupled thermally with the element 10 and the oscillation frequency (f) of an oscillation circuit 2 is determined depending upon the temperature of the object 6. Further, pyroelectric effect is obtained by the temperature variation of the object 6, a pyroelectric current is detected by a pyroelectric current detecting circuit 7, and an LPF 8 removes its high frequency component to generate an output voltage V indicating the temperature variation of the object 6. An MPU 3 calculates a controlled variable from the oscillation frequency and output voltage V and a temperature varying means 5 controls the temperature of the object 6 according to the controlled variable. Thus, the oscillation frequency (f) indicating the temperature itself and the output voltage V indicating the temperature variation are obtained directly, so the wide temperature range can be handled and the high-accuracy, high- stability temperature control is attained.
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Inventors:
KUMADA AKIRA
MURATA MITSUHIRO
OCHIAI KAZUKI
MURATA MITSUHIRO
OCHIAI KAZUKI
Application Number:
JP5466690A
Publication Date:
November 14, 1991
Filing Date:
March 06, 1990
Export Citation:
Assignee:
MURATA MANUFACTURING CO
International Classes:
G01K7/00; G01K7/32; (IPC1-7): G01K7/00; G01K7/32
Attorney, Agent or Firm:
Arisa Shinshiro