Patent ID: 9245779
Filing Date: 2016-01-26
CPC Classification: H01L,Y10T

Claim Text:
1. A method of preparing a thin film, comprising: coating a thin film-forming composition on a substrate; and heat-treating the coated thin film-forming composition under a pressure less than 760 Torr to form a hetero-structure thin film, the hetero-structure thin film including a first layer and a second layer on the first layer, wherein the thin film-forming composition includes a solvent, wherein the first layer has a refractive index of less that 1.85 and is more porous than the second layer, and wherein the method increases a thickness of the second layer having a refractive index in the range of about 1.85 to about 2.0 by increasing an evaporation rate of the solvent from the surface of the thin film-forming composition.