Optical film
An optical film comprises a transparent substrate including a top surface and a bottom surface; a micro-hemisphere layer disposed on the top surface of the transparent substrate and having a plurality of hemispheric projections, and an unsmooth diffusion layer disposed on the bottom layer of the transparent substrate. The micro-hemisphere layer condenses a light. The unsmooth diffusion surface diffuses a light.
1. An optical film adapted for use in a backlight module, comprising:
a transparent substrate including a top surface and a bottom surface;
a micro-hemisphere layer disposed on the top surface of the transparent substrate and being formed from acrylate resin and having a plurality of micro hemispheric projections; and
an unsmooth diffusion layer disposed on the bottom surface of the transparent substrate, wherein
the transparent substrate is free of diffusion particles,
the bottom surface is a light incident surface,
the unsmooth diffusion layer diffuses light, and
the micro-hemisphere layer condenses light and has a refractive index in the range between 1.3 and 2.0.
2. The optical film as claimed in claim 1 , wherein the transparent substrate is glass or plastic.
3. The optical film as claimed in claim 1 , wherein the thickness of the micro-hemisphere layer varies between 1 and 100 microns.
4. The optical film as claimed in claim 1 , wherein the micro-hemisphere layer comprises micro-hemispheres of various thicknesses.