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:
Apr. 18, 2006
Filed:
Sep. 17, 2004
Applicants:
Hirofumi Ueno, Tokyo, JP;
Tsutomu Takekawa, Tokyo, JP;
Inventors:
Hirofumi Ueno, Tokyo, JP;
Tsutomu Takekawa, Tokyo, JP;
Assignee:
Kabushiki Kaisha Toshiba, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 29/50 (2006.01); H01J 29/58 (2006.01);
U.S. Cl.
CPC ...
Abstract
A prefocus lens section is formed by a second grid and a third grid in a substantially rotation-symmetric fashion. A sub-lens section is formed by the third grid and a first segment. A main lens section is formed by a fourth grid and a fifth grid. The third grid is supplied with a voltage that is higher than a focus voltage and lower than an anode voltage. An electron beam, which is prior to entering the main lens section, is shaped to have a greater horizontal dimension than a vertical dimension.