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:
Jun. 04, 2002

Filed:

Apr. 27, 1998
Applicant:
Inventors:

Go Uchida, Mobara, JP;

Syoji Shirai, Mobara, JP;

Shinichi Kato, Mobara, JP;

Masafumi Nagaoka, Mobara, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G09G 1/04 ;
U.S. Cl.
CPC ...
G09G 1/04 ;
Abstract

A focus electrode is constituted by a first type of focus electrode group to which a first focus voltage is applied, and a second type of focus electrode group to which a second focus voltage is applied. Between the first type of focus electrode group and the second type of focus electrode group are formed a lens at least having a lens action for correcting the field curvature and an electrostatic quadrupole lens. The center axes of the outer electron beam passage holes in the first type of focus electrode forming the lens at least having a lens action for correcting the field curvature are deviated on a horizontal plane from the center axes of the outer electron beam passage holes in the second type of focus electrode. The electrostatic quadrupole lens produces dissimilar intensities for the outer electron beams and for the center electron beam. Therefore, the outer electron beam passage holes work to deflect the outer electron beams toward the center electron beam with an increase in the deflecting amount of the electron beams, and a favorable resolution is obtained on the whole screen of the cathode-ray tube.


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