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:
Oct. 02, 1990
Filed:
Jun. 24, 1988
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J / ; H01J / ;
U.S. Cl.
CPC ...
313493 ; 313611 ; 313612 ; 313634 ; 220 / ;
Abstract
A circular fluorescent lamp has a fluorescent tube of a generally circular shape having electrodes fixed gastight in both of its ends respectively to enclose inert gas and mercury therein. A cap is mounted to bridge between the tube ends. The fluorescent tube has an oval section taken along a line perpendicular with respect to its axis. The rate of ovalness y/x, representing the ratio between the larger tube diameter y and the smaller tube diameter x of the tube sectional shape, preferably lies within the range of 1.10 to 1.30.