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.
Patent No.:
Date of Patent:
Dec. 11, 1979
Filed:
Oct. 19, 1977
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
313414 ; 313449 ; 313460 ; 315 15 ;
Abstract
In a unipotential type electron gun including a main lens constituted by three coaxial and spaced apart electrodes for focusing an electron beams, the length of the intermediate electrode is made to be larger than 1.1D, where D represents the inner diameter of the electrodes on both sides, and the sum of the length of one electrode located on the side of a cathode electrode, the length of the intermediate electrode, the gap length therebetween, and the gap length between the intermediate electrode and the electrode on the opposite side is set to be in a range of from 4.0D to 5.4D.