This question typically comes up in the context of a customer either wanting to install a different window on the sensor package, or wanting to know if FLIR offers such a service.
FLIR`s microbolometer arrays are fabricated as a `vacuum package assembly`, or VPA. The VPA incorporates a silicon window. FLIR does not offer an option to deliver cameras or sensors without a window. Because the sensor is under vacuum, the window is a necessary component. The window is soldered to a metal housing that holds the focal plane array (FPA). FLIR can provide information as to the temperature at which the solder melts for customers who want to attempt de-soldering the window. Any such window removal / replacement would need to be performed in a clean room environment to avoid contamination of the fragile microbolometer bridge structures which would be exposed by removal of the window. A different window, if used, would need to be soldered onto the sensor housing, and the soldering process itself could potentially damage the microbolometer array. FLIR does not recommend or endorse any process or procedure described in this paragraph, and the camera warranty would be voided by any such modification(s).
In addition, there is no way to perform a system-level test without the FPA being under vacuum (i.e., no window), and FLIR`s test setup parameters are structured for the silicon window characteristics (in the case of a different window). Deviating from FLIR`s established VPA manufacturing process would require having to document and trace any new or different build configuration. There are also specification compliance and warranty concerns that FLIR would not be able to adequately address. More importantly, high-volume production requirements severely limit FLIR`s ability to accept special builds.