Cathode ray tube having a tubular electron gun structure
AssigneeU.S. Philips Corporation
InventorsGerardus A. H. M. Vrijssen, Tjerk G. Spanjer
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Abstract
The invention relates to a cathode ray tube having an envelope 1 comprising a screen 2 and an electron gun 3 which is situated inside the envelope 1 opposite to the screen and which has three electrodes 4, 5 and 6, which electrodes are provided coaxially on the inner wall of a glass tube 7 in adjoining places having diameters differing for each electrode. In order to obtain, for example, smaller dimensions and a better alignment of the electron gun and a higher resolution, a focusing lens associated with the electron gun 3 is a high-ohmic resistance layer 8 having a spiral shape 9.
Claims11
A cathode ray tube comprising an envelope containing a screen and an electron gun for producing an electron beam directed at said screen, said electron gun comprising:
- a. an insulating tube having a longitudinal axis and including a portion having a stepped inner surface defined by a plurality of inner wall sections situated at different positions along said axis and having differing perimeters;
- b. a plurality of electrodes disposed in respective ones of the inner wall sections of the insulating tube, said electrodes including means for supporting an electron-emitting cathode and for forming the emitted electrons into the electron beam;
- and
- c. a high-resistance layer disposed on an inner surface of the insulating tube and forming a spiral focusing lens at a position along the axis which will effect focusing of the electron beam at the screen.
Dependencies are inferred from the claim text.