mikrobolometer

A microbolometer, or mikrobolometer, is a type of uncooled infrared detector used to convert incident infrared radiation into an electrical signal. The sensing element absorbs infrared energy, producing a small rise in temperature that changes its electrical resistance, which is then converted into a measurable signal by a readout circuit.

Most microbolometers use a micromachined, thermally isolated membrane or bridge that supports a temperature-sensitive material, often a thin-film resistor such as vanadium oxide (VOx) or amorphous silicon (a-Si). An absorber coating enhances infrared absorption, while the underlying structural support minimizes heat loss to the substrate, enabling detectable resistance changes at or near room temperature.

Arrays of microbolometers form focal plane arrays (FPAs) in uncooled infrared cameras. Pixel pitches commonly range from about 12 to 25 micrometers, with VOx and a-Si as the common sensing materials. The sensing elements are read out by a dedicated readout integrated circuit (ROIC) that processes the resistance changes into image data.

Key performance metrics include noise-equivalent temperature difference (NETD), responsivity, and thermal time constant. NETD for uncooled microbolometers typically spans tens of millikelvin to several hundred millikelvin, while response times are on the order of a few to several tens of milliseconds.

Applications span security and surveillance, building and electrical inspections, industrial process monitoring, firefighting, and automotive night vision. The main advantages are room-temperature operation, lower cost, and simpler cooling requirements compared with cooled detectors; limitations include lower sensitivity and dynamic range, drift with ambient temperature, and slower frame rates relative to some cooled technologies.