APPARATUS AND METHODS FOR FORMING AND USE WITH VARIABLE PIT DEPTH OPTICAL RECORDING MEDIA

摘要

An apparatus (figure 2) and method for forming a digital optical disc master from a disc having a substrate (300) coated with a photoresist coating (320) . The method includes irradiating the surface of the photoresist material (320 ) with a laser beam (310) at a multiplicity of pit locations over the substrat e (300) causing the photoresist material (320) to react to the laser radiation (310) to form at least three different discrete levels at the multiplicity o f pit locations relative to the surface of the substrate (300) due to the dose of radiation applied being calculated to react with the photoresist to a dep th equivalent to the discrete levels. The exposed photoresist is then developed to achieve the pits having the different discrete levels. A further method i s disclosed for equalization and compensation for intersymbol interference between adjacent pits.