The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Oct. 16, 2001

Filed:

Mar. 02, 1999
Applicant:
Inventors:

Tomoki Nakamura, Mobara, JP;

Shoji Shirai, Mobara, JP;

Yasuharu Yatsu, Mobara, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 2/950 ;
U.S. Cl.
CPC ...
H01J 2/950 ;
Abstract

A color cathode ray tube includes a phosphor screen, an in-line type electron gun having an electron beam generating section for projecting three electron beams arranged in parallel with each other in a horizontal plane toward the phosphor screen, a focus electrode, and an anode adjacent to the focus electrode and forming a main lens in cooperation with the focus electrode for focusing the electron beams on the phosphor screen. The focus electrode includes at least a first focus sub-electrode and a second focus sub-electrode on the order named from the cathode, the first focus sub-electrode and the second focus sub-electrode forming an electrostatic quadrupole lens therebetween. An axial distance Lgf (mm) from an end of the first focus sub-electrode on a cathode side thereof to an end of the second focus sub-electrode on an anode side thereof, an axial distance Ls (mm) from the end of the second focus sub-electrode to the phosphor screen, and a useful diagonal dimension D (mm) of the phosphor screen satisfies a following relationship: 0.06×Ls (mm)≦Lgf≦26 (mm), and 1.50≦D/Ls≦1.70.


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