| 摘要 |
<p>A method for ignition of a ceramic high intensity discharge (HID) lamp (Fig. 2, 14). The ceramic HID lamp (14) includes an arc chamber (26) and two capillaries (25) each connected to the arc chamber (26) at respective proximal ends of the capillaries (25). Two electrodes (20) are each sealed within the capillaries (25) by respective seals (22) near the distal ends of the capillaries (25). The electrodes (20) extend from the seals (22) through respective bores (24) in the capillaries (25) and protrude into the arc chamber (26) at the proximal ends of the capillaries (25). The method includes applying to the electrodes (20) multiple pre-ignition voltage pulses PIP of sufficiently short duration to avoid igniting the HID lamp (14). The pre-ignition voltage pulses PIP heat the electrodes (20) prior to ignition to avoid arcing in the bores (24) of the capillaries (25) surrounding the electrodes (20). The ignition circuit (Fig. 1, 18) is configured subsequent to application of the pre-ignition voltage pulses PIP to apply an ignition pulse IP to ignite the HID lamp. Subsequent to the ignition, the HID lamp (14) is operated with an operating voltage (Fig. 4a, 40) which alternates between high frequency and low frequency waveforms. Using high and low frequency waveforms helps avoid acoustic resonance and flickering in the lamp.</p> |
