Reflective principle vehicle license is usually said retroreflective, traffic markings on the road, Chi warning signs is the same type of product, it is through the built-in glass bubble (also bare type) to achieve. According to the reflection intensity is generally divided into several categories: high-strength grade, license plate grade, engineering grade and advertising level.

Zhao donge, in order to test a glass bubble retroreflector screen divergent angle, high-speed camera glass bubble retroreflector screen reflected laser beam on the imaging screen vellum laser spot, spot image processing, according to certain geometric ratio between the calculated angle of divergence angle to the original reflective screen, which is in the range of 0.907 ° ~ 0.956 °.