| 摘要 |
PURPOSE: To attain a high efficiency during rated operation to allow the power control of a gas discharge lamp by setting the operating frequency of a lamp generator larger than the rated frequency in rated operation during preheating stage, and reducing the operating frequency until it reaches a predetermined state at the start of starting stage. CONSTITUTION: A gas discharge lamp can be dimmed by changing the operating frequency fB of a lamp generator, and the operating frequency fB of the lamp generator is set larger than the rated frequency fN in rated operation during a preheating stage (a). At the start of a starting stage (b), the operating frequency fB is reduced until it reaches a predetermined state, the operating frequency fB is reduced to the rated frequency fN at the end of the starting stage (b), whereby a rated operation (c) is started, and the operation frequency fB is changed for dimming during the successive dimming operation (d). Thus, regulation can be performed with a high efficiency in the rated operation, and the power control of the gas discharge lamp can be performed. |
