Multi-color infrared imaging device

摘要

A multi-color IR imaging device includes optics that direct mid-wave infrared (MWIR) and long-wave infrared (LWIR) radiation onto a focal plane array having LWIR and MWIR detection layers. Pixel groups that include at least one first pixel and one second pixel are defined on the focal plane array, and a first filter and a second filter which form part of an inhomogeneous filter is placed over the respective first and second pixels in a checkerboard pattern, in close proximity to the detection layers. This allows MWIR radiation in M band, and LWIR radiation in an L₁ band to pass therethrough and illuminate the first pixels, and M, L₁, and a separate LWIR band designated L₂ to pass therethrough and illuminate the second pixels. To simultaneously image both MWIR and LWIR, the focal plane array is placed at a predetermined distance from the optics so that the MWIR spot size covers a single pixel and the LWIR spot size is about the same area as the area of a group of two first pixels and two second pixels. Since all pixels receive the M band, half of the pixels in the group receive the L₁ band, and the other half receives the L₂ band, three bands can be generated. This allows simultaneous imaging of MWIR and two sub-bands of the LWIR from the same point in space.