What is FOCAL PLANE ARRAY?

2020-12-03

Normally we call focal plane array in the short name FPA.It is a special type of bolometer and is used as a thermal detector in infrared cameras.In photonics, a focal plane array (FPA) is essentially an array of light detectors, which is placed in the focal plane of an imaging system (a simple lens or an objective, possibly a telescope). It would actually be more accurate to talk about an image plane instead of a focal plane, which is not exactly the same.
FPA is based on a series of small thin-film bolometers arranged in a matrix in the focal plane of the detector. This results in a planar pixel sensor, allowing an improved price-performance ratio in various applications.

There are two types of material for the thin-film bolometers, one is vanadium oxide, the other is amorphous silicon,typical detector sizes today are 384x288 and 640x480 pixels.Whilst in the past pixels were generally 35x35 µm in size, now pixel sizes of 25x25 µm, 17x17 µm or even 12x12µm,MH-6100B uses 640x512,12µm. Among other things, the resulting reduction of the detector surface size also results in smaller and lower cost optical systems. 

Thermal detector with 12µm is better than 17µm .