Browse Prior Art Database

Advanced ROM Optical Disks

IP.com Disclosure Number: IPCOM000049958D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Durbeck, RC: AUTHOR [+3]

Abstract

A Lithographically patterned Optical Read-Only Memory (LOROM) comprises a substrate 10 upon which a pattern of thin metal islands 12 is formed and covered by a suitable overcoat 14 so that a suitable laser beam 16 can READ the pattern of data due to the reflectivity difference from the uncovered substrate to the metal islands.

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Advanced ROM Optical Disks

A Lithographically patterned Optical Read-Only Memory (LOROM) comprises a substrate 10 upon which a pattern of thin metal islands 12 is formed and covered by a suitable overcoat 14 so that a suitable laser beam 16 can READ the pattern of data due to the reflectivity difference from the uncovered substrate to the metal islands.

One LOROM structure, shown in the top figure, comprises a silicon substrate which has a selected pattern of metal islands produced by well-established lithographic techniques such as chemical etching, lift off or RIE, and covered by a suitable overcoat. A glass overcoat, for example, can be bonded to the substrate, while a polymer overcoat can be applied by a spin-coating technique. The overcoat is thick enough to keep dust particles on its surface out of the plane of focus of the reading laser beam.

A second LOR0M structure is shown in the second figure as one-half of a double-sided disk. The centerline of the structure is shown with a selected pattern of metal islands on each surface of the substrate (only one shown).

A third LOR0M structure (bottom figure) is a hybrid structure with an inorganic, transparent layer 18 (SiO2, for example) first deposited on a polymeric substrate 10' (PMMA, for example). Patterning is then done after depositing metal on the inorganic layer.

The LOROM structures can be fabricated by the use of readily available equipment and methods. The resulting LOROM structures have superior mec...