Double layer DVD surface - silver underside Science Image

Ref: 80017452



DVD surface. Coloured scanning electron micrograph (SEM) of the pits that encode information on a DVD (digital versatile disc). These pits are read by a focused laser as the disc rotates. This is a double-layer DVD, which can hold up to 8.5 gigabytes (GB) of information. The upper layer (not seen) is semi-transparent and gold in colour. This silver-coloured layer is bonded to the underside of the gold layer with a clear adhesive. After the laser has read the information on the gold layer (from the centre of the disc outwards), the laser refocuses itself to read from the silver layer, from the outer edge inwards. Magnification: x5850 at 6x7cm size.