English to Italian Law/Patents Engineering: Industrial Microfluidics

The text is about the manufacturing of a valve element in a mold. Here, it explains that the presence of a protrusion in the mold causes the formation of a draft angle and a resulting "step difference". The sentence is as follows:

"The injection product has a step difference such that when the valve is operated by applying energy, such as electromagnetic waves, the step difference of the injection hole may cause diffusion of light".

Any ideas about the meaning of this term?
Thank you very much for the help.