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:
Jul. 14, 1992
Filed:
Mar. 04, 1991
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
315105 ; 315101 ; 315107 ; 3152 / ; 315D / ;
Abstract
A lighting device for a hot cathode fluorescent lamp used for a back light of a liquid crystal display or the like attempts to prolong the life of a lamp in a lighting device for a low consumption wattage fluorescent lamp. More specifically, the hot cathode fluorescent lamp is started while being pre-heated, and even after starting, a pre-heat current keeps flowing. The pre-heat current value after starting is set to be smaller than that at the time of starting for the purpose of optimizing the hot spot temperature. With employment of the configuration as described above, the lifetime of the hot cathode fluorescent lamp when used as a back light can extend to 10,000 hours or more.