In this video demonstration I explained about Single Layer, and Dual Layer (DL) DVD’s storage capacities, logic behind DL DVD’s less storage data, data storage basics on DVD’s.
A DVD is composed of several layers of plastic, totaling about 1.2 millimeters thick. Each layer is created by injection molding polycarbonate plastic. This process forms a disc that has microscopic bumps arranged as a single, continuous and extremely long spiral track of data. More on the bumps later.
Once the clear pieces of polycarbonate are formed, a thin reflective layer is sputtered onto the disc, covering the bumps. Aluminum is used behind the inner layers, but a semi-reflective gold layer is used for the outer layers, allowing the laser to focus through the outer and onto the inner layers. After all of the layers are made, each one is coated with lacquer, squeezed together and cured under infrared light. For single-sided discs, the label is silk-screened onto the nonreadable side. Double-sided discs are printed only on the nonreadable area near the hole in the middle.