AbstractDespite successful commercialization of uncooled microbolometers suitable for imaging, the community is still searching for a platform for imagers that combine affordability, convenience of operation, and excellent performance. More recently, a new type of uncooled detectors based on expansion phenomena in micromechanical structures has been introduced. These detectors are essentially free of intrinsic electronic noise and can be combined with a number of different readout techniques including: capacitive, piezoresistive, electron tunnelling, and optical. In this paper, their design structures and performance are discussed in more detail.