Medium and method for erasably recording data by viscoelastic shear deformation

摘要

An erasable optical data storage medium has a polymer dual recording layer (10) including an expansion layer (14) bonded to a retention layer (16), each of the layers dyed to selectively absorb light in respective narrow wavelength bands. The retention layer (16) has a glass transition temperature substantially above the glass transition temperature of the expansion layer (14), and is capable of undergoing substantial viscoelastic shear deformation (22) while below its glass transition temperature. A first laser beam B1 heats the expansion layer (14) causing it to expand and cause viscoelastic deformation in the retention layer (16) while the retention layer (16) is below its glass transition temperature. A second laser beam B2 is used to heat the retention layer (16) above its glass transition temperature and relax the deformation (22), erasing the medium.