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. 26, 1999
Filed:
May. 14, 1998
Koito Manufacturing Co., Ltd., Tokyo, JP;
Abstract
A lighting circuit for a discharge lamp is designed in such a way that a detection time for the flicker state of a discharge lamp is not affected by the light-OFF time at the time the discharge lamp flickers without causing a significant increase in cost. This lighting circuit 1 for a discharge lamp comprises detection means 5 for detecting a flicker state of a discharge lamp 3; and abnormality determining means 6 for determining an abnormality in the discharge lamp 3 in accordance with a detection signal from the detection means 5 and implementing display to that effect, or stopping power supply to the discharge lamp 3, whereby when the detection signal from the detection means 5 indicates repetition of a state where a light-OFF time of the discharge lamp 3 is equal to or greater than a first set time and a light-ON time of the discharge lamp 3 is equal to or less than a second set time is repeated a predetermined period or longer, or a predetermined number of times or more, the abnormality determining means 6 determines the state as abnormal lighting of the discharge lamp 3.