Pyroelectric Effect

The responsive element of pyroelectric infra-red detectors is a thin crystal between two electrodes. A temperature change results in a change of the spontaneous polarisation in the material, which causes charges to build up at the electrodes. These charges are converted to a signal voltage at the detector output by an amplifier. The voltage is proportional to the incident radiation flux.

Detector Properties

Important detector properties are the responsivity, Sv, the noise and the specific detectivity, D*. All these properties depend on frequency and temperature.

Typical Circuit Diagrams

Pyroelectric infra-red detectors work in either voltage or current mode. The voltage mode is mostly used. In order to use the large signal-to-noise ratio of these infra-red detectors, a low-noise design of signal amplifier is important.

Spectral Properties

The spectral properties depend on the infra-red filter and the absorbency of the responsive element. For our customised single and multi element infra-red detectors a wide range of spectral filters is available. An additional black coating applied to the responsive element guarantees a high spectral uniformity of responsivity.