MULTI-STACK OPTICAL STORAGE MEDIU

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. An optical storage medium, which has the DVD format, comprising an entrance face;
below the entrance face, a higher recording stack comprising a higher recording layer, the higher recording layer comprising an organic dye material and having a thickness greater than 28 nm and less than 116 nm and a refractive index, below the higher recording stack, at least a lower recording stack, the lower recording stack being recorded or read back by a radiation beam entering the optical storage medium through the entrance face with a wavelength, focused on the lower recording stack and transmitted through the higher recording stack, a recording of the higher recording layer causing a difference in optical thickness between recorded and unrecorded areas of the higher recording layer, which lies within the range of 0.03λ to 0.125λ, wherein λ is the wavelength of the radiation beam which is approximately equal to 655 nm.