Browse Prior Art Database

Electro Optical Data Storage Mechanism

IP.com Disclosure Number: IPCOM000087333D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Callahan, RW: AUTHOR

Abstract

An electro-optical disk-pack-type data storage mechanism is described which provides recording densities some 10-to-20 times greater than that obtainable for a magnetic disk pack. Also, the access time is several orders of magnitude less than for a magnetic disk pack.

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Electro Optical Data Storage Mechanism

An electro-optical disk-pack-type data storage mechanism is described which provides recording densities some 10-to-20 times greater than that obtainable for a magnetic disk pack. Also, the access time is several orders of magnitude less than for a magnetic disk pack.

As indicated in Fig. 2, the storage or recording medium is a thin layer 10 of high persistence phosphor material coated onto the upper surface of a rotary disk
11. The writing and reading elements are multitrack arrays of light-emitting diodes and light detecting photodiodes mounted on the underside of a stationary array board 12, located just above the phosphor layer 10.

Fig. 1 shows a plan view of the underside of the array board 12. The writing of information or data onto the phosphor layer 10 is accomplished by a radially disposed integrated circuit array 13 of light-emitting diodes (LEDs), there being a separate LED for each recording track on the phosphor layer 10. Reading is accomplished by multiple integrated circuit photodiode arrays 14, each of which is disposed along a radius of the disk and each of which has a separate photodiode for each record track on the phosphor disk. The multiple read arrays 14 are spaced around the disk to enable multiple simultaneous searches and multiple simultaneous reading of data. The photodiodes in the read arrays 14 are+ preferably of the PIN or avalanche type.

The phosphor preferably has a persistency such that the information or data recorded thereon will decay to ten percent of its peak value in approximately two revolutions of the disk. Data is refreshed every revolution of the disk by a refresh head 15, which comprises a photodiode read array 15a and an LED rewrite array 15b. As with the other arrays, the arrays 15a and 15b have a separate photodiode or LED for each record track on the phosphor disk. Data is erased by simply degating the refresh circuitry for the track or tracks in question.

Fig. 3 shows a conceptual representation of the mechanism, the LED 13a representing one of the light emitting diodes in the array 13 and the PIN photodiode 14a representing one of the photodiodes in one of the arrays 1...