In order to reduce contrast degradation in an electrostatically scanned flat cathode ray tube having a channel plate electron multiplier due to back-scattered electrons entering channels remote from their origin, steps are taken to restrict the acceptance angle of the channel plate electron multiplier. In one arrangement means are provided on the input surface to restrict the angle of entry to a range normally associated with the addressing electron beam. In another arrangement the ready emission of secondary electrons is restricted to a predetermined arcuate portion of the input of each channel of the electron multiplier. In either arrangement stray electrons are unable to impinge upon the secondary emitting material in the channels and in consequence produce many fewer back-scattered electrons. Optionally a material having a low back-scatter coefficient and a microscopically rough surface texture may be applied to the exposed surfaces, apart from the apertures, of the input side of the electron multiplier to reduce the number of back-scattered electrons.
申请公布号
DE3469393(D1)
申请公布日期
1988.03.24
申请号
DE19843469393
申请日期
1984.07.05
申请人
PHILIPS ELECTRONIC AND ASSOCIATED INDUSTRIES LIMITED;N.V. PHILIPS' GLOEILAMPENFABRIEKEN
发明人
WOODHEAD, ALFRED WALTERS;GILL, RONALD WILLIAM ARTHUR;KNAPP, ALAN GEORGE;LAMPORT, DAPHNE LOUISE;WASHINGTON, DEREK