When it comes to the effective sterilization range, it is also based on the concept of dose. Unfortunately, for a point light source, the intensity distribution of the illuminated surface of the plane is similar to the Gaussian distribution, and there can be several times the intensity difference at the center and the edge. If the customer is rigorous in asking this question, we should carry out more accurate optical simulation to calculate the intensity distribution in different parts of the plane. The simulation may not be accurate enough, but it provides a qualitative reference for our scheme design. The radiation surface is not uniform, and the simulation tool can calculate it clearly.

In defining the luminous angle of a lamp bead, the angle between half of the peak intensity is used. It is suggested that we should also define the position of half peak intensity on the plane as the effective range in the scheme design, and the dose calculation should also be based on the half height position.

Because LED light pattern is spherical like, the uniformity of intensity distribution is very different between near and far places. At 20 cm, the ratio of the effective irradiation area to the whole irradiated surface is larger.