Attempts to make a disc that doubles as a CD and a DVD have so far foundered. The idea of a “flipper” disc – made by gluing a DVD and CD back-to-back – has been rejected because it was so thick it jams in some players. But now German inventor Dieter Dierks is patenting a new approach (WO 03/034418).
The new double act is the usual 1.2 millimetres thick, with CD data pits on one surface and a DVD data layer 0.6 mm below. The CD pits are transparent to the red laser light used by the DVD system. And the…
