| 摘要 |
PURPOSE:To enable stable heat sensing by combination of both functions of a constant temp. type and a differential type without mulfunction by detecting both of temp. and temp. rising rate with a pyroelectric element provided with an impedance conversion circuit. CONSTITUTION:An FET2 of an impedance conversion circuit connecting to an output resistance 4 is connected to a pyroelectric element 1 which is an insulator connected with an input resistor 3 and detects the IR corresponding to a temp. of high resistance. The DC bias voltage of the FET2 changes according to the change rate of ambient temp. and the AC signal superposed on a DC bias by the radiation IR energy of an object to be measured of temp. chopped through an IR transmission window is taken out from said FET. Both of the temp. rising rate and the temp. are detected by such DC bias signal and AC signal. The stable heat detection is thus accomplished by the combination of both functions of a constnat temp. type and a differential type without malfunction. |
