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Optical Content Addressable Retrieval System

IP.com Disclosure Number: IPCOM000094593D
Original Publication Date: 1965-Mar-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 51K

Publishing Venue

IBM

Related People

Zwieg, HJ: AUTHOR

Abstract

The optical associative memory has four information storage planes 1...4. Each plane is divided into nine bit positions. A digit is stored by the presence or absence of a hole in a bit position of the particular plane. For example, position 21 contains a punched hole to represent a 1. A word in the memory consists of the corresponding bits in each plane. For example, position one stores the word 0110. Position two has the word 1100.

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Optical Content Addressable Retrieval System

The optical associative memory has four information storage planes 1...4. Each plane is divided into nine bit positions.

A digit is stored by the presence or absence of a hole in a bit position of the particular plane. For example, position 21 contains a punched hole to represent a 1. A word in the memory consists of the corresponding bits in each plane. For example, position one stores the word 0110. Position two has the word 1100.

Each plane consists of a sheet of material which absorbs light in a particular band of frequencies. The absorption band of the sheets in each of the four planes is different. A matrix of photoreceptors is positioned below the four planes. There is one photoreceptor for each bit position.

The memory is interrogated to find whether or not it contains a particular desired word by sequentially illuminating it with two different colors of light. First, the memory is illuminated with light which contains the color associated with the planes in which the desired word has 0's. If the desired word is in any position of the memory, the associated photoreceptor receives no light. This is because the planes associated with the 0's in the word absorb their particular colors and no light reaches the photoreceptor. Next, the memory is illuminated with light containing frequencies corresponding to the absorption bands for the positions of the desired words which have 1's. If the desired word is stored in the memory, the planes that have the 1's have punched holes. Hence, at any position of the memory which contains the desired word this second illumination is not absorbed and it reaches the photoreceptor.

In another arrangement, for example, each plane can consist of a layer of diazo material....