Array detectors, such as front-illuminated CCDs and CMOS, have a thick layer of silicon dioxide, silicon nitride, metal, etc., above the effective silicon absorption layer, which strongly reflects, refracts, and absorbs ultraviolet light. Consumer-grade back-illuminated CCD and CMOS detectors have a surface coated with a high K film that strongly absorbs ultraviolet light. At the same time, there is a visible light anti-reflective film, which has a strong interference reduction effect on ultraviolet light. These factors all result in poor response of the array detectors to ultraviolet light.
Specialized semiconductor processing techniques are utilized to enhance the response of array detectors to ultraviolet or soft X-rays. However, this method significantly escalates the overall cost.
Based on many years of coating experience, Pumo Spectrum has launched a chip coating service that can coat a fluorescent film (such as Lumogen, GdO2S) on the surface of CCD and CMOS detectors to convert ultraviolet or soft X-rays into visible light, which is then received by the detector.
Through the optimization of different materials and processes, the ultraviolet enhancement coating of Spectrum Technology can respond to ultraviolet incident light as low as 50nm.