Method of driving discharge lamp, driving device, and projector
AssigneeSeiko Epson Corporation
InventorsKentaro Yamauchi, Takeshi Takezawa
Life of this patent
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Abstract
A method for driving a discharge lamp having a first electrode and a second electrode includes the steps of, in a situation where a tip portion of the first electrode becomes higher than a tip portion of the second electrode in temperature when power of the same amount is fed to the first and second electrodes during a steady operation, changing a difference between the absolute values of average current values for two polarities during one cycle of the AC current in accordance with a predetermined pattern, and setting an operation time ratio of the first electrode as an anode during one cycle so as to be smaller than an operation time ratio of the second electrode as an anode during one cycle.
Claims14
A method for driving a discharge lamp that supplies an AC current to a discharge lamp having a first electrode and a second electrode so as to produce discharge and to cause the discharge lamp to emit light, comprising the steps of:
- changing a difference between the absolute values of average current values for two polarities during one cycle of the AC current in accordance with a predetermined pattern, and
- setting an operation time ratio of the first electrode as an anode during one cycle so as to be smaller than an operation time ratio of the second electrode as an anode during one cycle when a tip portion of the first electrode becomes higher than a tip portion of the second electrode in temperature when power of the same amount is fed to the first and second electrodes during a steady operation in which the AC current is supplied to the discharge lamp.
A driving device that supplies an AC current to a discharge lamp having a first electrode and a second electrode so as to produce discharge and to cause the discharge lamp to emit light, the driving device comprising:
- a current driving circuit that changes a difference between the absolute values of average current values for two polarities during one cycle of the AC current in accordance with a predetermined pattern, and sets an operation time ratio of the first electrode as an anode during one cycle so as to be smaller than an operation time ratio of the second electrode as an anode during one cycle when a tip portion of the first electrode becomes higher than a tip portion of the second electrode in temperature when power of the same amount is fed to the first and second electrodes during a steady operation in which the AC current is supplied to the discharge lamp.
Dependencies are inferred from the claim text.