| 摘要 |
PURPOSE:To electronize and downsize a whole lighting apparatus by a method wherein one of switching elements is chopper-operated at the time of lighting a lamp after start-up to have a high voltage pulse generating circuit inactivated while the lamp is lit with a direct current supplied to a discharge lamp. CONSTITUTION:This apparatus comprises a high voltage pulse generating circuit 4 comprising a DC power source VDC, two switching elements S1, S2, a voltage raising circuit 7 and an oscillating circuit 8, a capacitor C8 for cutting direct current, capacitors C9, C10, etc. At the time of start-up, the switching elements S1, S2 alternatively perform on/off inverter operation to operate the high voltage pulse generating circuit 4 to apply high voltage pulses to a discharge lamp, while at the time of lighting the lamp one of the switching elements S1, S2 is chopper-operated to have the high voltage pulse generating circuit inactivated so that high voltage pulses can be stopped without an exclusive switch. Since lighting of the discharge lamp is thus performed by chopper-operation, the whole lighting apparatus can be electronized and compacted. |
