Apple Inc.
Forming white metal oxide films by oxide structure modification or subsurface cracking

Abstract:

The embodiments described herein relate to forming white appearing metal oxide films by forming cracks within the metal oxide films. In some embodiments, the methods involve directing a laser beam at a metal oxide film causing portions of the metal oxide film to melt, cool, contract, and crack. The cracks have irregular surfaces that can diffusely reflect visible light incident a top surface of the metal oxide film, thereby imparting a white appearance to the metal oxide film. In some embodiments, the cracks are formed beneath a top surface of a metal oxide film, thereby leaving a continuous and uninterrupted metal oxide film top surface.