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Alkali Halide Target for Cathode Ray Tube

IP.com Disclosure Number: IPCOM000094733D
Original Publication Date: 1965-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Arnoult, JE: AUTHOR [+3]

Abstract

A target for dark trace cathode ray tubes exhibits improved strength and resistance to flaking. The target permits faster erasure and greater light transmission when constructed of a metallic screen substrate coated with potassium chloride.

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Alkali Halide Target for Cathode Ray Tube

A target for dark trace cathode ray tubes exhibits improved strength and resistance to flaking. The target permits faster erasure and greater light transmission when constructed of a metallic screen substrate coated with potassium chloride.

The display target for dark trace cathode ray tube 1 is constructed by tautly stretching 500-mesh metallic screen 2 in frame 3. Electrodes 4 are connected to opposite sides of screen 2. An alkali halide salt 5, such as potassium chloride, is evaporated onto both sides of screen 2 to form the target. Evaporation can be accomplished in an atmosphere of inert gas, e.g., argon, at pressures of 10/-3/ mm. of mercury or greater to obtain low density deposition and fill the screen openings. The target is then mounted in evacuated tube 1.

Writing, effected by the electron gun, is viewed by transmitting light through the tube and coated screen from light source 6. A reflective coating is unnecessary. Target erasure is accomplished by resistive heating of screen 2 via electrodes 4. Such erasure permits rapid temperature elevation of the coating and eliminates the need for radiant heater filaments. Targets with 18,000 write-erase cycles reveal no evidence of flaking.

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