Far infrared thermal imaging system

摘要

A far-infrared image is directed onto a transducer having a planar array of absorbing discs on one side. The discs are supported by a thin membrane which expands and bulges as the discs heat up. The discs thus change their spacing with respect to a partially reflective mirror. The nominal spacing between the discs and mirror is about 1/4 wavelength of the infrared radiation, such that absorption is enhanced. The mirror is supported on a transparent substrate through which visible or near-infrared light is shown, and carries a perforated mask atop an insulating layer and in registration with the discs. The mirror/discs thus establish a Fabry-Perot cavity for the visible or near-infrared light, whereby a visible or near-infrared image may be observed or detected as the various discs establish various spacings in accordance with incremental variations in the infrared image. An electrostatic field is established between the mirror and the shield by a voltage source. This field induces an electrostatic field in the discs to pre-bias the discs toward the mirror and thus to tune or adjust the sensitivity of the transducer.