| abstract |
The record comprises an absorptive layer (22) with a capping layer (24) overlying it to inhibit irreversible recording in the absorptive layer, and possibly a reflective layer (18) and a transparent spacer layer (20). An information track in the absorptive layer (22) comprises a sequence of regions in the absorptive layer whose optical properties have been reversibly changed for instance by a change in their crystallinity, thereby changing the reflectivity of the information record in these regions. Information may be recorded by exposing the information recording medium to a modulated light beam so that its optical properties in exposed regions of the absorptive layer (22) are reversibly switched to a second state. Erasure is effected by exposing the recording medium to a light beam so that the optical properties of the switched regions are reversibly returned to about their original values, permitting further recording. <IMAGE> |