Precise mid-field modeling for UVC LEDs by using a fluorescent film

This paper presents the mid-field model for an ultraviolet C light emitting diode (UVC LED) of wavelength around 275 +/- 5 nm by comparison of the 2-dimension (2-D) gray-level image captured from a mono-CMOS sensor and simulated irradiance pattern. Because of UVC light, we propose using a fluorescent film to absorb UVC light and re-emit visible light so that the 2-D image could be captured. The analysis and calibration to obtain accurate gray level of image are performed. Finally, we achieve the mid-field model with high accuracy. Furthermore, this model is also applied for dome lens design and then compares the performance with fabricated samples in measurement to expertise its validity. (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement