US Patent 7554093 Uniformly responsive ultraviolet sensors

The fluorescent response of a UV radiometer to a UV beam is normalized over an entrance aperture area by using a plurality, preferably two, converting plates. The fluorescent response of at least two and preferably a plurality of crystal converting plates is ascertained. Crystal converting plates having complementary responses are selected and placed adjacently in the entrance aperture area such that an incident UV beam will cause a net complementary fluorescent response from the combined first and second crystal converting plates that is less varying over the entrance aperture area than the respective fluorescent responses of the individual first and second crystal converting plates.