The AF coating should know
Mar 02, 2026
AF means anti-fingerprint. It's the reason for why a new phone screen feel smooth and doesn't show every smudge. If no, glass would feel stricky and look dirty minutes after touch it.
The working principle
The coating is a fluoropolymer layer, typically from 5 to 20 nanometers thickness which is about 100,000 times thinner than human hair. It bonds in glass surface and lower the surface energy. Oils and water can't spread out-they bead up instead.
The manufacturers measure performance of using contact angles, water should bead at 115° or higher. Oil around 100°. Higher numbers mean better repellency.
Application methods
2 ways to apply to dominate the industry.
Vacuum deposition uses plasma to vaporize the coating material and bond it to glass . Stronger adhesion, longer life, but costs more. Used for premium phones.
Spray coating costs less but doesn't last as long. The coating sits on top rather than bonding molecularly . Still fine for mid-range devices.
Some newer equipment now combines AR, DLC, and AF coatings in one vacuum chamber . Cuts handling steps and contamination risk.
Durability problem
AF coatings wear off. That's for why old screens feel rough and smudge constantly.
The standard test use steel wool rubbing under 500g load. Good coatings survive 3000~5000 cycles. After the test, contact angles drop down and the screen will feel different.
Sweat speeds up wear. Phones in pockets, watches on wrists. The combination of friction and chemistry breaks down the layer.
