Patent ID: 7362692

Claim:
A method of mass producing double-sided optical discs, said discs having one or more data layers on each side, comprising: providing data from a controller to a master producing process; producing with the process master discs, including a set of master discs for the layer or layers of one side and second set of master discs for the layer or layers of the other side, the first set of master discs having data arranged along a first spiral, and the second set of master discs having data arranged along a second spiral, said first and second spirals being mirror images of each other; and using said master discs to form said double-sided optical discs, said first set of master discs includes an inner and an outer master disc for the first side and the second set of master discs includes an inner and an outer master disc for the second side; wherein the step of producing said master discs includes forming on said discs at least one special area defining rotation direction indicia for the discs to be mass produced, said special area including data disposed in a third spiral opposite the direction of the first spiral.