U.S. Philips Corporation

John R Mansell

Alan G Knapp

Derek Washington

Willem M Van Alphen

Hewson Nicholas King

Colin D Overall

Pamela May Stubberfield

Henry D Stone

A color display tube which has a channel plate electron multiplier for multiplying a low voltage, low current electron beam and thereby obtaining an amplified output beam for producing an image on a screen 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 into well defined dots and rings to obtain good color purity, the source-to-screen distance of the output beam is varied in a predetermined manner. A means for doing this comprises additional electrodes mounted on the output side of the electron multiplier.

Color display tube with channel electron multiplier means

A channel plate electron multiplier is mounted parallel to, but spaced from, the screen. The electron multiplier comprises a stack of juxtaposed substantially planar apertured dynodes with the apertures therein aligned to form channels. An apertured extractor electrode is mounted on the output side of the electron multiplier. Preferably two or more foraminous deflector electrodes are mounted on the extractor electrode. The apertures in the foraminous deflector electrodes have the same pitch as the channels of the electron multiplier but are offset laterally relative to each other and to the axes of the channels by amounts which allow the emergent electron beam from each channel to pass through to the screen without impinging upon the deflector electrodes. By applying a potential difference between the deflector electrodes an electron beam emerging from its respective channel is deflected laterally onto a respective one of its associated group of phosphor stripes. The apertures in the deflector electrodes may be circular, elliptical or polygonal for example square, rectangular or hexagonal.

Color cathode ray tube including a channel plate electron multiplier

A cathode ray tube comprising a channel plate electron multiplier structure disposed between a source of electrons and an output device such as a cathodeoluminescent screen. The electron multiplier comprises a stack of n apertured dynodes which are separated from each other and are arranged in cascade with the apertures in adjacent dynodes aligned to form channels. In order to improve the resolution of the electron multiplier while enabling the dynodes to be aceptably rigid the axial profile of the apertures in at least the second to the (n-1)th dynodes is such that it comprises a re-entrant portion within the thickness of the dynode with the axially spaced ends of the re-entrant portion being spaced from the respective opposite surfaces of the dynode by a convergent or cylindrical input portion and a divergent or cylindrical output portion. The axial length of the re-entrant portion corresponds substantially to the cross-section of the input (or output) portion at a point where it communicates with the re-entrant portion.

Cathode ray tube and an electron multiplying structure therefor

A deflection color selection system for a single beam channel plate display tube includes, within an envelope 10, a laminated dynode channel plate electron multiplier (16) having channels whose exit apertures are aligned in columns. An apertured extractor electrode (36) is mounted on and electrically insulated from an output face of the electron multiplier (16), the apertures (42) in the extractor electrode (36) being aligned with respective channels. A luminescent screen (14) spaced from the extractor electrode (36) includes patterns of phosphor elements (R, G, B) adapted to luminesce in different colors. A current multiplied electron beam 34 exiting from an aperture in the extractor electrode is deflected onto an associated pattern of phosphor elements by pairs of first (38) and second (40) deflector electrodes insulated electrically from each other and from the extractor electrodes, the first (38) and second (40) deflector electrodes being disposed as pairs between each column of apertures (42) in the extractor electrode (36). All of the first electrodes (38) are interconnected as are all of the second electrodes (40). This electrode arrangement enables good resolution and electrical correction of misalignment errors between the electron multiplier (16) and the screen (14).

Color picture display tube

Channel plate image intensifiers, for use as raster intensifiers in cathode ray tubes for example, comprise a stack of alternately arranged perforate laminar dynodes M and perforate laminar separators D aligned to form electron multiplier channels P. Each of the separators comprise a perforate aluminium plate having an anodized layer some 15 microns thick on the plate surface. Such separators can be manufactured to have the desired electrical characteristics and uniform thickness over their entire area so that the dynodes M are parallel to each other and provide a uniform gain over their entire area. The invention also relates to a method of anodizing perforate and imperforate aluminium foils.

Channel plate electron multipliers

A color cathode ray tube having a screen with concentric phosphor ring patterns and an electron multiplying channel plate between the screen and the electron gun, the channel plate including a focusing control electrode having a constant focusing action.

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East Grinstead, United Kingdom

John R Mansell