Long-Wave Infrared Filters

LWIR Filters

Materion Balzers Optics is the leading manufacturer of LWIR filters used for temperature measurement and thermal imaging. Our windows and filters can have engineered transmission and reflection between 8 and 14 µm. For LWIR cameras, a window can be coated with an antireflective coating on one face and a longpass filter on the other face. Our filters can be metallized to be compatible with hermetic solder assembly. Materion Balzers Optics can also supply LWIR windows soldered into a Kovar frame or conical housing. Materion Balzers Optics can coat Ø 200 mm Si window cavity wafers for bonding onto microbolometer ROIC wafers. Narrow bandpass filters in the LWIR are also available, with a bandwidth to center wavelength ratio down to 1%.

Benefits

High transmittance in the LWIR passband
Blocking of shorter wavelengths
Long-term, shift-free spectral performance
High environmental stability
Metallization to enable hermetic soldering
Solder assembly into Kovar frames or housings
Ø 200 mm wafers for wafer-level packaging

Applications

LWIR windows and filters are used for thermal imaging cameras. Such cameras can be used to measure the temperature of exposed human skin (e.g., foreheads) for the detection of fevers. LWIR cameras are also used to detect heat leaks in building insulation, overheated transformers or circuit breakers. LWIR cameras are used for surveillance, to detect humans and vehicles at night. LWIR cameras can also see through fog and are commonly used as a navigation aid aboard cars, trucks, ships and aircraft.