A high directivity TIR (total internal reflection) lens in the UV-A region was designed using a silicone resin, and a UV light source module with a maximum irradiation density of 150 mW/cm2 was fabricated. The beam angle of the TIR lens was designed to be 8.04° and the maximum diameter of the TIR lens was ø13.5. A silicone resin having a UV transmittance of 93% and a refractive index of 1.4 at a wavelength of 365 nm was used, and the lens was manufactured using an aluminum mold, from which silicone could be easily released. The module was fabricated in a metal printed circuit board of COB (chip on board) type using a 0.75×0.75 mm2 UV chip. A jig was used to adjust the focal length between lens and chip and to fix the position of the lens. The optical characteristics such as illumination distributions of the lens and module were designed using ‘LightTools’ optical simulation software. The heat dissipation system was designed to use a forced-air cooling method using a heat-sink and fan.
