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. 28, 1999
Filed:
Sep. 12, 1996
Noboru Yamamoto, Kariya, JP;
Kenji Yoneima, Oobu, JP;
Masamichi Ishikawa, Hekinan, JP;
Hiroaki Okuchi, Anjo, JP;
Hiromi Hiramatsu, Kariya, JP;
Denso Corporation, Kariya, JP;
Abstract
In a discharge lamp device, the electric power supplied to a discharge lamp is controlled in order of first to fourth control regions from the start of lighting of the discharge lamp. In the first control region, the lamp current is held constant until the lamp voltage reaches a first voltage value. In the second control region, the lamp current is reduced so as to have a correlation with a first time constant curve for a constant time after the lamp voltage reaches the first voltage value. In the third control region, the lamp current is reduced so as to have a correlation with a second time constant curve after a lapse of the constant time. The second time constant curve differs from the first time constant curve. In the fourth control region, a control value of the electric power supplied to the discharge lamp is free of a function of a lapse of time from the start of lighting of the discharge lamp, but is a function of at least the lamp voltage and the lamp current, and the electric power supplied to the discharge lamp is controlled by that control value. Through such a control, luminous flux is built up in a short time from the start of the lighting and an occurrence of overshoot or undershoot is minimized to a possible extent.