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. 05, 2004

Filed:

May. 01, 2003
Applicant:
Inventors:

Yasufumi Wada, Takatsuki, JP;

Hiroji Morimoto, Kashihara, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J 2/950 ; H01J 2/952 ;
U.S. Cl.
CPC ...
H01J 2/950 ; H01J 2/952 ;
Abstract

A focusing electrode and a final accelerating electrode accommodate, respectively, a first and a second field forming electrode in positions set back from a first and a second aperture of their end faces opposed to each other. The first and the second field forming electrode have three electron beam passage apertures disposed in an in-line arrangement. When the in-line direction is an X-axis direction, a direction perpendicular to the in-line direction is a Y-axis direction and the center of a central electron beam passage aperture formed in the first field forming electrode is X=0 and Y=0, the central electron beam passage aperture has a shape that passes through the intersection points of the X-axis and the Y-axis with a curve represented by the equation (X/R1) +(Y/R2) =1 (where R1 and R2 are constants) and that has an area smaller than the area encircled by the curve.


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