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. 07, 1999
Filed:
Feb. 13, 1998
Eitaro Nishigaki, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A piezoelectric transformer drives a cold cathode tube under the control of a light controller; when the cold cathode tube is radiating in a small luminous intensity range, the light controller changes the duty factor of a driving signal supplied to the piezoelectric transformer so as to adjust the cold cathode tube at a target luminous intensity, and prevents the cold cathode tube from undesirable luminous gradient; when the cold cathode tube is radiating in a large luminous intensity range, the light controller changes the frequency of the driving signal so as to adjust the cold cathode tube to a target luminous intensity, and prevents a power supply unit from undesirable frequent load variation.