Multi-stack optical storage medium

摘要

The invention relates to an optical storage medium comprising below an entrance face (EF) a higher recording stack (ST0) comprising a higher recording layer (L0) and at least a lower recording stack (ST1), said lower recording stack (ST1) being recorded or read back by a radiation beam (4) entering into the optical storage medium through the entrance face (EF) with a wavelength (λ), focused on said lower recording stack (ST1) and transmitted through the higher recording stack (ST0), a recording of the higher recording layer (L0) causing an optical thickness variation between recorded and unrecorded areas of said first recording layer (L0), which is included into the range [0.03λ, 0.125λ].

主权项

1. A multi-stack optical storage medium in a disk format with at least one stack receiving a radiation beam through another stack, comprising:
a semi-transparent first substrate, with an entrance face and pre-grooved face on the opposite side from the entrance face, and a thickness within a range of 0.56 mm and 0.60 mm; a higher stack and a lower stack, separated by a spacer having a thickness within a range of 0.03 mm and 0.07 mm extending between the pre-grooved face of the semi-transparent first substrate and a second substrate, and including respective recording layers, the recording layer of the higher stack having a thickness on groove and a variation of thickness on groove between recorded and unrecorded areas equal to a first range of 0.06λ to 0.08λ; and the entrance face is configured for receiving the radiation beam having a wavelength (λ) less than or approximately equal to 655 nm and a wave front phase variation of within the first range for recording data on the recording layers, wherein data is recorded on the recording layer of the higher stack by the beam passing through the entrance face alone and on the recording layer of the lower stack by the beam passing through the entrance face and through the recording layer of the higher stack, wherein the recording layer of the higher stack comprises an organic dye material having: the thickness on groove greater than 28 nm and less than 115 nm.