COLOUR DISPLAY TUBE

摘要

A colour display tube (10) which has a channel plate electron multiplier (22) for multiplying a low voltage, low current electron beam (18) and thereby obtaining an amplified output beam (60) for producing an image on a screen (24) formed of a plurality of different phosphors arranged as dots, each of which is surrounded by at least one ring. In order to form the output beam (60) into well defined dots and rings to obtain good colour purity, the source-to-screen distance of the output beam (60) is varied in a predertermined manner. A means for doing this comprises additional electrodes (50), (52) and (54) mounted on the output side of the electron multiplier (22).