A STUDY ON THE RESPONSIVITY OF FOUR-LAYER PYROELECTRIC SENSORS

초록

The temperature distribution under periodic thermal excitation and the pyroelectric response of a four-layer system consisting of front and back semi-infinite media, a pyroelectric element, and an intermediate layer are found. Numerical results and approximate expressions are obtained for special cases, such as a detector with an air gap between the pyroelectric layer and the bulk substrate and a detector on a substrate of finite thickness an air environment. The responsivities of detectors with a lead-lanthanum-titanate (PLT) sensing element on either a Si and a SiO2 substrate are calculated as functions of the pyroelectric layer and the underlying layer thicknesses. It is found that the detector with an air gap has a frequency-independent responsivity over a wide frequency range. A correlation is found between the type of frequency response in each frequency region and the corresponding dominant mechanism for heat loss.