Optical thin film and edge-type backlight module containing the same

An edge-type backlight module comprising:

• a light source;
• a light guide plate disposed on one side of said light source;
• and
• an optical thin film disposed on said light guide plate and including a transparent substrate and first and second light-condensing layers, said transparent substrate having a first surface and a second surface which is opposite to said first surface, said first light-condensing layer being formed on said first surface of said transparent substrate, said second light-condensing layer being formed on said second surface of said transparent substrate, said first light-condensing layer having a haze value ranging from 5% to 30% and a surface roughness ranging from 0.1 RMS to 1 RMS, and said second light-condensing layer having a haze value ranging from 70% to 100% and a surface roughness ranging from 1 RMS to 10 RMS.