pyroelectricdetektorer

Pyroelectric detectors, or pyroelectric infrared detectors, are devices that generate an electrical signal from infrared radiation by exploiting the pyroelectric effect in suitable crystalline or ceramic materials. They are typically uncooled and operate at or near room temperature, offering a compact and cost-effective option for infrared sensing.

The operating principle relies on a temperature change in the detector’s pyroelectric material when it absorbs infrared energy. A rapid temperature change induces a change in the material’s electric polarization, producing a charge that can be measured by a high‑impedance readout circuit. Because the signal is proportional to the rate of temperature change, pyroelectric detectors respond to modulated or changing infrared flux rather than a steady level of radiation. In practice, the detected signal is often enhanced by modulating the incoming IR with a chopper or by using differential element configurations, and it is amplified by a low-noise preamplifier.

Materials commonly used in pyroelectric detectors include lithium tantalate (LiTaO3), lithium niobate (LiNbO3), and various pyroelectric ceramics, as well as polymer ferroelectrics such as PVDF. Detectors are frequently packaged with infrared windows and coatings to tailor spectral response and protect the sensing element. Two-element configurations are popular in motion sensing (PIR) devices, while single-element or arrays are employed in thermal imaging and spectroscopy.

Key performance parameters include responsivity, detectivity, noise, response time, and the need for signal modulation. Advantages include room-temperature operation and simplicity, while limitations involve sensitivity to ambient temperature drift and relatively slower response compared with cooled detectors for some high‑end applications.