Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Patent
1984-04-12
1987-01-13
Cardillo, Raymond F.
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
369284, 369286, 369111, 365113, G11B 700, G11B 722
Patent
active
046370080
ABSTRACT:
An optical erasable disk memory system which utilizes duration modulated laser switching is disclosed. The disk storage system utilizes a disk-shaped storage medium which includes a planar substrate and a thin film of phase change material. A substantially transparent optical tuning layer and protective layer are also utilized in the preferred embodiment of the present invention. The phase change material utilized is sensitive to both stress and temperature variations and will change from a first optically discernible phase to a second optically discernible phase at any portion thereof subjected to a temperature in excess of a selected threshold temperature at a particular stress and will change from the second phase back to the first phase at any portion thereof subjected to a stress in excess of a selected threshold stress at a particular temperature. A duration modulated laser is selectively utilized to heat particular portions of both the planar substrate and the thin film of phase change material to increase the temperature of the phase change material above the threshold temperature at those portions. A shorter duration laser pulse is utilized to heat selected portions of the phase change material without permitting the heat to dissipate into the substrate. The heated phase change material expands at a greater rate than the non-heated planar substrate and thereby increases the stress at those selected portions to a stress above the selected threshold stress.
REFERENCES:
patent: 3778785 (1973-12-01), Von Gutfeld
patent: 3789420 (1974-01-01), Claytor et al.
patent: 3789421 (1974-01-01), Chivian et al.
patent: 4125860 (1978-11-01), Ishii et al.
patent: 4314262 (1982-02-01), Reilly
patent: 4322839 (1982-03-01), Yamashita et al.
patent: 4371954 (1983-02-01), Cornet
patent: 4385376 (1983-05-01), Takaoka et al.
Chaudhari, "Optical Memory", vol. 16, No. 2 Jul. 1973, IBM Tech. Dis. Bulletin.
D. W. Pohl et al., "Laser-Induced Phase Transition in the Surface of SmS Crystal", Applied Optics, vol. 13, No. 1, Jan./1974, pp. 95-97.
Von Gutfeld "Structures for Reversible SmS Optical Memories", IBM Tech. Dis. Bulletin, vol. 16, No. 1, 6/73, pp. 108-109.
Cardillo Raymond F.
Cate J. M.
LTV Aerospace and Defense
Nguyen Hoa T.
Sadacca S. S.
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