Mikrombolometer

Mikrombolometer, commonly called a microbolometer, is a type of uncooled infrared detector used to form thermal imaging cameras. Unlike cooled infrared detectors, microbolometers operate at or near room temperature and do not require cryogenic cooling. They sense infrared radiation by converting absorbed energy into heat in a thin-film thermistor, which produces a change in electrical resistance.

A typical microbolometer pixel consists of a thin-film absorber on a thermally isolated micro membrane, often made of silicon nitride. The sensor materials most commonly used are vanadium oxide (VOx) or amorphous silicon, chosen for their strong temperature coefficient of resistance. When infrared radiation is absorbed, the pixel temperature rises slightly, causing a measurable change in resistance. The array of such pixels is fabricated on a common readout integrated circuit (ROIC) to form a focal-plane array (FPA) using MEMS-based microfabrication techniques.

Operation involves biasing the thermistor and reading out resistance changes as voltage signals, which are then processed to create thermal images. Performance is typically described by the noise-equivalent temperature difference (NETD), which for microbolometer cameras ranges from tens to a few hundred millikelvin, depending on design. The thermal response and speed are governed by the thermal time constant of the pixels, and high-volume packaging and calibration are required to maintain image quality.

Applications include security and surveillance, industrial inspection, firefighting, automotive night vision, and medical or building diagnostics. Microbolometers offer compact, cost-effective, uncooled infrared sensing suitable for wide deployment, with ongoing improvements in materials, pixel architecture, and readout electronics.