Browse Prior Art Database

Refresh And/Or Storage Mode Operation of Direct-View EL Storage CRT

IP.com Disclosure Number: IPCOM000046554D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Sahni, O: AUTHOR

Abstract

The present publication provides a refreshed write-through capability for an electroluminescent (EL) CRT to allow for cursor, etc., operation by electron-beam charge selection. The EL storage faceplate 1 consists of a ZnS:Mn active layer 2, sandwiched between two insulating films 3 (e.g., BaTi03). The AC coupled structure is driven by an AC voltage applied between a transparent conducting film 4 (viewing side) and a thin Al film 6 (on the E-beam side). The electron beam 8 is used to switch this active face plate 1 between its bistable states. The refreshed write-through mode requires the E-beam to display information without perturbing visibly the bistable off state of the store structure on which it is being traversed. Cathodoluminescence by itself is too weak in the EL faceplate structure to provide sufficient luminosity.

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Refresh And/Or Storage Mode Operation of Direct-View EL Storage CRT

The present publication provides a refreshed write-through capability for an electroluminescent (EL) CRT to allow for cursor, etc., operation by electron-beam charge selection. The EL storage faceplate 1 consists of a ZnS:Mn active layer 2, sandwiched between two insulating films 3 (e.g., BaTi03). The AC coupled structure is driven by an AC voltage applied between a transparent conducting film 4 (viewing side) and a thin Al film 6 (on the E-beam side). The electron beam 8 is used to switch this active face plate 1 between its bistable states. The refreshed write-through mode requires the E-beam to display information without perturbing visibly the bistable off state of the store structure on which it is being traversed. Cathodoluminescence by itself is too weak in the EL faceplate structure to provide sufficient luminosity. The present proposal utilizes repetitive injection of charge by an electron beam pulse at a voltage pause of zero volts, and the temporal decay of this charge leads to a sensitive control of the residual bulk charge in the active film upon reimposition of the EL voltage drive. This technique allows sufficiently small quantities of charge to be injected into the active region to enhance the electroluminescence in the initial drive cycles, thereby acting as a pulsed excitation which decays with time rather than permanently switching the bistable filaments of the ZnS film 2. For example, the waveform shown in Fig. 1 was used to reduce this proposed concept to practice. The present approa...