“…When the light passes through the surface with microstructure, a refraction event occurs between the interface of the film and the air, and the incident light is deflected from its course, resulting in light diffusion. There are various methods for fabricating surface-relief type such as replica molding method [14,15], embossing process [7,16,17], lithography [8,18,19], electrospray method [20,21], etching [22,23], holographic technology [24], etc. According to the different preparation methods, the micro-structure can be a hemisphere [14,15,20,21], paraboloidal shape [8], polygonal shape [3,26], pyramid [27,28], cylindrical lens [16], V-shaped mirror [17], or irregular type [4,19,22,23], etc.…”