Optical members, method for producing the same and display devices comprising the same

A method of manufacturing an optical member, the method comprising:

• preparing a transparent substrate;
• depositing an alumina-based ceramic material on the transparent substrate, the alumina-based ceramic material having a silica-free composition;
• and
• heat-treating and washing the alumina-based ceramic material after the depositing.

An optical member, comprising:

• a transparent substrate;
• an alumina-based first transparent ceramic layer on the transparent substrate;
• and
• an alumina-based second transparent ceramic layer on the alumina-based first transparent ceramic layer such that the alumina-based first transparent ceramic layer is between the transparent substrate and the alumina-based second transparent ceramic layer,
• wherein the alumina-based first transparent ceramic layer has a non-porous structure and the alumina-based second transparent ceramic layer has a porous structure,
• wherein a refractive index of the alumina-based second transparent ceramic layer is smaller than a refractive index of the alumina-based first transparent ceramic layer.