Protective film called "rainbow pattern" because when the substrate during the hardening process requires high temperatures once, and in high-temperature treatment, the molecular structure of the substrate surface is scattered unevenly situation. The higher the intensity of hardened, rainbow pattern difficult control. Rainbow pattern affects the presence of light transmission and visual effects. High-quality film after the protective film is hard to see with the naked eye rainbow pattern. So rainbow pattern is actually hardened product, the higher the intensity of hardened, it means that the protective film rainbow pattern more powerful, without affecting the visual effects of the premise, to achieve the best effect of hardening treatment generally only to 3.5H to 3.8H between....