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Storage CRT With Selective Erasure Capability

IP.com Disclosure Number: IPCOM000076520D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Chang, IF: AUTHOR

Abstract

This storage cathode-ray tube (CRT) has a selective-erase capability, whereby information can be selectively removed from discrete portions of the storage screen. In contrast with normal CRT's where a transparent backplate or a front mesh is used as a collector covering the entire screen, two sets of collector wires are employed, as shown in the drawing. Either the transparent back set 1 or the front set 2 performs as a normal collector in a conventional manner. That is, a high-voltage pulse is applied to either collector to perform the erase function. As the high-voltage pulse drops, the entire screen falls to an "off" state which is maintained steadily by a flood-electron beam until a higher energy writing beam changes a selected target to an "on" state.

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Storage CRT With Selective Erasure Capability

This storage cathode-ray tube (CRT) has a selective-erase capability, whereby information can be selectively removed from discrete portions of the storage screen. In contrast with normal CRT's where a transparent backplate or a front mesh is used as a collector covering the entire screen, two sets of collector wires are employed, as shown in the drawing. Either the transparent back set 1 or the front set 2 performs as a normal collector in a conventional manner. That is, a high-voltage pulse is applied to either collector to perform the erase function. As the high-voltage pulse drops, the entire screen falls to an "off" state which is maintained steadily by a flood-electron beam until a higher energy writing beam changes a selected target to an "on" state.

In the CRT shown, the two sets of collector wires are orthogonal to one another. Although these are shown as being directed in the x and y directions, various other orthogonal arrangements can be used. In order to erase an "on" element at any location (x, y), erasure pulses are applied to the orthogonal pair of collector wires which intersect in the area o the selected target. This causes erasure of the information at that selected target.

In the case of alphanumeric display, sections of the target screen can be erased by applying erasure pulses to groups of collector wires in each collector set. For instance, erasure pulses are applied to the front set of collector...