Discharge lamp lighting device and lighting system
First Claim
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1. A discharge lamp lighting device, comprising:
- a high-frequency generating circuit which outputs high-frequency voltage;
a discharge lamp having a pair of filament electrodes, the discharge lamp being lighted by the high-frequency voltage applied across the filament electrodes;
a current detector detecting preheat current which flows through the filament electrodes of the discharge lamp;
a voltage detector which detects voltage generated in either one filament electrode of the pair of filament electrodes; and
a controller which computes impedance of either one of the filament electrodes from the preheat current detected by the current detector and the detecting voltage of the voltage detector, and controls to preheat and light the discharge lamp in accordance with the computed impedance.
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Abstract
When a discharge lamp is preheated, impedance of a filament electrode of the discharge lamp is computed. In accordance with the computed impedance, preheating and lighting of the discharge lamp are controlled.
12 Citations
16 Claims
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1. A discharge lamp lighting device, comprising:
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a high-frequency generating circuit which outputs high-frequency voltage; a discharge lamp having a pair of filament electrodes, the discharge lamp being lighted by the high-frequency voltage applied across the filament electrodes; a current detector detecting preheat current which flows through the filament electrodes of the discharge lamp; a voltage detector which detects voltage generated in either one filament electrode of the pair of filament electrodes; and a controller which computes impedance of either one of the filament electrodes from the preheat current detected by the current detector and the detecting voltage of the voltage detector, and controls to preheat and light the discharge lamp in accordance with the computed impedance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification