“Near-infrared” (NIR) is the portion of the electromagnetic spectrum directly adjacent to the visible range; therefore it cannot be perceived with the human eye. NIR-optimized industrial cameras are popular for applications that need to utilize this wavelength range, e.g. applications with poor light conditions, such as traffic monitoring. Until now, these applications were only possible with infrared cameras with expensive CCD sensors.
Now, new CMOS technology can do the job, providing sensors with increased sensitivity in the near-infrared range over 850 nm. It achieves this through the application of a thicker substrate layer (as compared to a monochrome sensor) for the visible spectral range. The new CMOS technology has made NIR optimization affordable, through a line of industrial cameras with excellent sensitivity in the near-infrared, which in turn has boosted their share on the machine vision market.
The NIR-optimized cameras with NIR-optimized 2 MP (CMV2000) and 4 MP (CMV4000) sensors from CMOSIS, or the 1.3 MP sensor (EV76C661) from e2V, still manage quantum efficiencies close to 40% in the 850nm range. Compared to non-NIR-optimized cameras, this represents a doubling of the sensitivity value at this wavelength.