Browse Prior Art Database

Selective Erase Method

IP.com Disclosure Number: IPCOM000078752D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kozol, ET: AUTHOR [+2]

Abstract

This method allows selective erasing of displayed information in a deformographic storage-display tube (DSDT). Such type tubes are described in U. S. Patent Nos. 3,626,084 and 3,676,588.

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Selective Erase Method

This method allows selective erasing of displayed information in a deformographic storage-display tube (DSDT). Such type tubes are described in
U. S. Patent Nos. 3,626,084 and 3,676,588.

Using only the write gun, information is written onto the surface of insulating mica member of the target assembly on the DSDT by a high-velocity electron beam, typically 10 kV. The charges formed are negative with respect to the ultor. To erase or neutralize these charges, a 1.5 kV electron beam is required.

To achieve this selective erase mode, the ultor potential is reduced from what is polarity 10 kV to +1.5 kV. The deflection system and write-gun focus potential are rescaled electronically to match the new ultor value. The write gun now acts as a focused and deflection controlled erase beam, which is selectively positioned onto the desired imagery for erasure. The 1.5 kV electrons removes excess electrons by secondary emission at these locations and returns these locations back to an uncharged state. In rewriting new or corrected information, the ultor is returned to a 10 kV level with the focus and deflection rescaled for writing. Stored imagery is unaffected by these ultor excursions.

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