Browse Prior Art Database

Dark Trace Storage Tube System

IP.com Disclosure Number: IPCOM000077498D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Kazan, B: AUTHOR

Abstract

The dark trace cathode-ray tube (CRT) is provided with a conventional electron gun 10 comprising anelectron-emitting cathode 11, a control grid 12 for controlling beam intensity, a focussing electrode 13 and an accelerating anode 14. Deflection coils 15 are connected to a source of conventional x, y deflection signals. The face of the CRT contains a cathodochromic viewing screen 16 with a thin phosphor layer 17 on its back surface. Voltage is applied to accelerating anode 14 to allow the electron beam, modulated by an input signal, to penetrate phosphor layer 17 and darken viewing screen 16 in the region determined by the input signal and, therefore, produced a pattern on the screen.

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Dark Trace Storage Tube System

The dark trace cathode-ray tube (CRT) is provided with a conventional electron gun 10 comprising anelectron-emitting cathode 11, a control grid 12 for controlling beam intensity, a focussing electrode 13 and an accelerating anode
14. Deflection coils 15 are connected to a source of conventional x, y deflection signals. The face of the CRT contains a cathodochromic viewing screen 16 with a thin phosphor layer 17 on its back surface. Voltage is applied to accelerating anode 14 to allow the electron beam, modulated by an input signal, to penetrate phosphor layer 17 and darken viewing screen 16 in the region determined by the input signal and, therefore, produced a pattern on the screen.

During the initial writing mode, switch 18 is open and the screen is scanned with a relatively low-beam current and a high-writing speed, thereby producing a dark-trace pattern having minimal contrast, for example, 5% or less. After the dark-trace pattern is written, the input signal is cut off and the accelerating voltage on anode 14 is reduced, for example, from 20 to 10 kilovolts. By scanning the screen in raster fashion, the electron beam generates a flying light spot on phosphor layer 17 which is partially penetrated, causing limited darkening of cathodochromic screen 18.

During the scanning operation, also referred to as the signal intensification sequence, switch 18 is closed. The light from the phosphor screen which passes through the cathodochr...