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US 7,253,568 B2Granted
High pressure discharge lamp lighting apparatus
AssigneeUshio Denki Kabushiki Kaisha
InventorsKatumi Sugaya, Tsuyoshi Sugihara, Yoshikazu Suzuki
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AssigneeUshio Denki Kabushiki Kaisha
InventorsKatumi Sugaya, Tsuyoshi Sugihara, Yoshikazu Suzuki
Estimating the term…
It is an object of the present invention to provide a high pressure discharge lamp lighting apparatus, has a structure to control decrease of illuminance on a screen which is thought to be a cause of wear of an anode in an early stage of the life span. The high pressure discharge lamp lighting apparatus has a high pressure discharge lamp in which a pair of electrodes is arranged so as to face each other at an interval of 2 mm or less in an arc tube which is made of quartz glass, and mercury of 0.16 mg/mm3 or more, rare gas, and halogen of 1×10−6 to 1×10−2 μmol/mm3 is enclosed, and a power supply apparatus supplying direct current to the discharge lamp, wherein the power supply apparatus superimposes an alternating component on the direct current and impress the superimposed current to the discharge lamp.
A high pressure discharge lamp lighting apparatus having a high pressure discharge lamp in which a pair of electrodes is arranged so as to face each other at an interval of 2 mm or less in an arc tube which is made of quartz glass, and mercury of 0.16 mg/mm3 or more, rare gas, and halogen of 1×10−6 to 1×10−2μmol/mm3 is enclosed, and a power supply apparatus supplying direct current to the discharge lamp, wherein the power supply apparatus superimposes an alternating current component on the direct current and impress the superimposed current to the discharge lamp, wherein a frequency of the alternating current component is 40 to 5000 Hz. and 0.05≦(Imax−Imin)/IDC≦2 wherein Imax represents a maximum current value of the alternating current component, Imin represents a minimum current value of the alternating current component and IDC represents direct current value.
A method of forming a projection at a tip of an anode of a high pressure discharge lamp in which a pair of electrodes is arranged so as to face each other in an arc tube, and mercury of 0.16 mg/mm3 or more, rare gas, and halogen of 1×10−6 to b 1×10−2 μmol/mm3 is enclosed, comprising the following steps of:
Dependencies are inferred from the claim text.