OPTICAL INFORMATION RECORDING MEDIUM

摘要

PURPOSE:To enable tracking servocontrol, by providing at least one concentrically circular reference track on each or either of the inside and outside circumferences of a disc substrate. CONSTITUTION:At least one concentrically circular reference track 2' on each or either of the inside and outside circumference of a disc substrate 1. A silver salt emulsion layer 6 is formed on the substrate 1 as a laser beam recording layer. A desirable width of the reference track 2' is 1-10mum. During laser beam recording, laser beam scanning is carried out while measuring the position of laser beams from the track 2'.