1. Optics must be selected to balance intensity against beam profile
By reviewing the illustration, it is apparent that there is a design trade-off involved. Wide-angle beams provide smooth and even profiles, but narrow-beams provide the intensity needed for fluorescent inspection. A well-designed LED inspection lamp needs both for the best results.
2. Common LED optics are made from PMMA
UV-A LEDs present an extra challenge for optics. Common LED optics are made from PMMA (acrylic) – it’s cheap, easily molded into the required shape, and transparent for visible light. However, PMMA absorbs UV and will solarize (yellow and cloud over). The same phenomenon can be seen in older automotive headlights - with exposure to the UV from the sun the clear plastic becomes cloudy.