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Browse Prior Art Database

Deformographic Storage Display Tube

IP.com Disclosure Number: IPCOM000084281D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Sansom, A: AUTHOR

Abstract

Electrostatic target display tubes of the kind described in U.S. Patent 3,676,588 establish high potentials on the storage surface, which can deflect the electron beam at both erase energy (approx. 2KV) and write energy (approx. 10KV) as it approaches the target. A difficulty is thus created in correct positioning of the beam, particularly in selective erase and rewrite operations.

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Deformographic Storage Display Tube

Electrostatic target display tubes of the kind described in U.S. Patent 3,676,588 establish high potentials on the storage surface, which can deflect the electron beam at both erase energy (approx. 2KV) and write energy (approx. 10KV) as it approaches the target. A difficulty is thus created in correct positioning of the beam, particularly in selective erase and rewrite operations.

This results from the fact that the beam enters the field of prior written information at a substantial distance from the target, so that even relatively moderate fields deflect the beam substantial distances by the time it reaches the target.

An appropriately mounted mesh screen 10 positioned approximately an eighth of an inch away from the target 12 on the beam approach side serves to isolate the beam from the influence of written information on the target 12, until the beam has passed through the mesh 10. The remaining travel distance is so short that deflection effects are negligible.

An electroformed nickel mesh of, for example, 750 lines per inch and transmission of 50% to 60% has been found to be satisfactory.

In addition, the mesh 10 isolates the target 12 from that positive ion degradation of the previously written information which can occur during continued writing. Only ions generated in the small space between the mesh and target will be attracted to the negative going written areas.

Electrostatic target display tubes have been found to...