Erasable optical read/write data storage system

Abstract

An erasable optical read/write data storage system is disclosed. The data storage system utilizes a temperature sensitive data storage disk which includes an optical tuning film and a film of thermochromic phase change material which will change from a first phase to a second phase at temperatures in excess of an upper temperature and back to the first phase at temperatures below a lower temperature. An environmentally controlled chamber is provided to maintain the data storage disk at a selected bias temperature between the lower and upper temperatures to ensure that no unintentional phase change will occur. A thermally controlled support member is utilized to temporarily lower the temperature of the disk to a point below the lower temperature, thereby initializing the disk. A modulated laser beam is then focused on the disk to temporarily heat particular portions of the disk to a temperature in excess of the upper temperature, causing a phase change. The same laser beam at lower power levels may be utilized to optically discern the phase of a particular portion of the disk by means of the variations in reflectivity between the two phases. In a preferred mode of the present invention, a plurality of storage disks are utilized and transfer means are provided to maintain each disk at the bias temperature during storage and transfer. In still another mode of the invention, individually controllable groups of thermoelectric elements embedded near the surface of an integrated disk and support member may be utilized to selectively heat and cool particular sections of the data storage disk, thereby permitting selective erasure of portions of the data encoded thereon.