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:
Sep. 17, 2002
Filed:
Sep. 20, 2001
Susumu Okura, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention provides a lighting device of a discharge lamp, which lights the discharge lamp by feeding power to the discharge lamp, comprising a voltage detecting section which detects voltage impressed on the discharge lamp, and a lighting stop determining section which determines, on the basis of the voltage detected by the voltage detecting section, whether or not a short-circuit or a ground-fault occurs in a power feed line to the discharge lamp, and stops lighting in response to the result of the determination, wherein determination whether or not a ground-fault or a short-circuit occurs is not made for a prescribed period of time after dielectric breakdown of the discharge lamp or for a prescribed period of time after flow of a prescribed current to the discharge lamp. It is therefore possible to prevent an erroneous detection caused by use of an unstable bulb voltage in the initial stage of lighting.