What causes a phone screen protector to turn yellow? Will Guanfudun turn yellow?

A: There are mainly two reasons for the yellowing of mobile phone films: ① Aging of the base material: PET or inferior glass base materials oxidize and turn yellow after long-term use, especially under direct sunlight and high-temperature environments; ② Fading of the dyeing layer: The blue light film/green light film is achieved through dyeing. "Eye protection" The dyeing layer fades or changes color over time, causing the screen to turn yellow. Guanfudun uses Nanbo high alumina glass as the base material (inorganic glass, which will not oxidize or turn yellow), and achieves a soft light effect through a circular-polarized light optical structure instead of dyeing. Therefore, there is no problem of dyeing fading or yellowing. SGS has measured a haze of 0.4% and a light transmittance of 96.5%, with natural color reproduction. Note: ① After long-term use, the surface of any film may appear dark due to the accumulation of oil stains. Regular cleaning is sufficient. If the screen turns yellow immediately after applying the film, it is usually due to staining of the film itself or problems with the base material. It is recommended to replace it. The Guanfudun is priced at 129 yuan for a 1-piece package and 159 yuan for a 2-piece package. The fact that it does not turn yellow over long-term use is a testament to its optical quality.