Patent Number: 6,294,866

Title: Color cathode ray tube having a low-distortion electrostatic quadrupole lens with a plurality of first and second electrodes having specified spacing relationships

Abstract: A color cathode ray tube includes a phosphor screen, an electron beam generating section for generating three in-line electron beams, a focus electrode and an anode. The focus electrode includes a first focus and second focus sub-electrodes on this order from the cathode structure. The first focus sub-electrode has plural vertical parallel plate-like electrodes arranged to sandwich respective beam apertures in an end thereof facing the second focus sub-electrode in a direction of a beam arrangement, and the second focus sub-electrode has plural horizontal parallel plate-like electrodes arranged to sandwich beam apertures in an end thereof facing the first focus sub-electrode in a direction perpendicular to the beam arrangement, one of the first and second focus sub-electrodes is adapted to be supplied with a voltage varying in synchronism with beam deflection. The vertical parallel plate-like electrodes extend into a space defined by the horizontal parallel plate-like electrodes, and a vertical spacing V between the horizontal parallel plate-like electrodes and a gap L between the horizontal parallel plate-like electrodes and the edges of the vertical parallel plate-like electrodes satisfy 0.38.ltoreq.L/(V/2).ltoreq.0.58.

Inventors: Uchida; Go (Mobara, JP), Shirai; Shoji (Mobara, JP), Kato; Shinichi (Mobara, JP), Nagaoka; Masafumi (Sakura, JP)

Assignee: Hitachi, Ltd.

International Classification: H01J 29/48 (20060101); H01J 029/50 (); H01J 029/70 (); H01J 029/46 ()

Expiration Date: 09/25/2018