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:
Jun. 10, 2008
Filed:
May. 12, 2004
Toshiyuki Noguchi, Nishinomiya, JP;
Yasuhiro Kakimoto, Takatsuki, JP;
Toshiyuki Noguchi, Nishinomiya, JP;
Yasuhiro Kakimoto, Takatsuki, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An operating device control section () controls an output current of a DC-DC converter (), and also controls a commutation frequency of a commutator () that converts a direct current output from the DC-DC converter into an alternating current. The operating device control section operates a discharge lamp, at the start of lamp operation, with a predetermined voltage value lower than a rated voltage and a first target current value higher than a rated current, then, at an end of a predetermined high frequency start period (T) elapsed from the start of lamp operation, controls the commutator to switch from a commutation frequency higher than that during a steady lamp operation to a commutation frequency during the steady lamp operation, and then, after a voltage applied to the discharge lamp increases and reaches a voltage not lower than a predetermined threshold voltage (Vth) which is not higher than the rated voltage, controls the DC-DC converter to switch from the first target current value to a second target current value which is not higher than the rated current to operate the discharge lamp. A temperature of a lamp electrode can be increased quickly and sufficiently to reduce a time required to increase the lamp illuminance, thereby reducing a time required to cause video to be viewable.