Infrared neutral density filters are usually used in gas thermal detection for industrial purposes.
Thermal cameras manufacturers usually need to attenuate the intensity of the incoming light that saturates their photodetector or to increase the operating range of the cameras.
Optical Density (OD) is the key factor in neutral density filters. It specifies the attenuation degree.
The physical resistance to scratching is also an important parameter.
The higher it is, the more lifetime of the filter. Mapsi’s filters are extremely robust to scratching, since silicon it is.
Neutral Density Filters in the MWIR and LWIR ranges are mainly used to partially and uniformly block the light that arrives a thermal camera.
In that way the same percentage of light is transmitted in all wavelength in the desired range.
This is usually used in industrial application to span the detection range of the thermal cameras and, thus, monitor processes at higher temperatures than allowed by the thermal camera without ND filter.
For instance, a ND filter with a transmission of 10% (Optical Density, OD, of 2.0) can expand the temperature range of [-25, 150] ºC to [50, 1000] ºC.
Our filters have proven to maintain their optical response when heated up to 200°C or immersed in water.
They also do not scratch if cleaned with paper or dry wipes or alcohol.
They are highly resistant to hostile or unclean environments. In addition, they avoid the Narcissus effect, so the filter should not have an inclination with respect to the detector, facilitating the design of the thermal imaging camera.