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:
Nov. 22, 2005
Filed:
Dec. 17, 2002
Takahisa Hamaguchi, Tokyo, JP;
Hiroyasu Kisaichi, Tokyo, JP;
Takahisa Hamaguchi, Tokyo, JP;
Hiroyasu Kisaichi, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A high pressure discharge lamp lighting apparatus is provided which prevents dying out or instabilities of the discharge arc inside the arc tube due to the acoustic resonance phenomena and enables to light the high pressure discharge lamp in a steady state. In the high pressure discharge lamp lighting apparatus having the high pressure discharge lamp, the lamp voltage detecting device, the high frequency power supplying device, and the control circuit, the apparatus includes an extracting device for extracting an upper limit frequency and a lower limit frequency of the resonance-free frequency band, and the control circuit includes a frequency moving device for changing the frequency of the high frequency power within a range defined by the upper limit frequency and the lower limit frequency extracted by the extracting device and then moving the frequency to a predetermined frequency which is determined based on the upper limit frequency and the lower limit frequency.