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 substrate (300) causing the photoresist material (320) to react to the laser radiation (310) to form at least three different discrete levels at the multiplicity of 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 depth equivalent to the discrete levels. The exposed photoresist is then developed to achieve the pits having the different discrete levels. A further method is disclosed for equalization and compensation for intersymbol interference between adjacent pits.