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Browse Prior Art Database

Photoconductive Matrix Memory

IP.com Disclosure Number: IPCOM000095369D
Original Publication Date: 1965-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Habegger, MA: AUTHOR

Abstract

Storage of binary information is accomplished in a read-only memory formed of a semiconductor slab. The information storage depends on the light sensitivity of the discrete locations of the slab.

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Photoconductive Matrix Memory

Storage of binary information is accomplished in a read-only memory formed of a semiconductor slab. The information storage depends on the light sensitivity of the discrete locations of the slab.

Semiconductor slab 1 is connected at appropriate terminals in a single wire circuit to source of potential 2 and load resistor 3. The voltage across resistor 3 is monitored by meter 4 to determine the information that is stored.

Slab 1 is considered to be formed of a plurality of discrete photoconductive elements 5, 6, and 7 arranged in a two-dimensional matrix. The binary information is storable in the matrical locations by selecting the level of light sensitivity for each element. Readout of the stored information is performed with a light beam provided by source 8. The light beam is deflectable to any location in the matrix with a digital light deflector.

To store information at a particular location in the matrix, the sensitivity of the semiconductive material to incident radiation such as light, is either decreased or left unaffected at that location to provide the binary states of information storage. A decrease in the light sensitivity is accomplished by directing an electron beam at that location. The beam has the effect of reducing the minority carrier lifetime in the semiconductor material thus reducing the light sensitivity at that location. The light sensitivity can also be decreased by locally diffusing a material which forms ad...