Method and device for driving a metal halide lamp
AssigneeKoninklijke Philips Electronics N.V.
InventorsJohannes Jacobus Geijtenbeek, Johan Leopold Hendrix, Fransiscus Vermeulen
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Abstract
A method for driving a metal halide lamp (1) is described, the method comprising the step of generating a light controlling DC electric field E with a desired direction and a desired strength inside the lamp such as to obtain a desirable ion distribution inside the lamp. The lamp is supplied with a commutating current with a DC component, preferably having a constant current intensity and a duty cycle differing from 50%. By setting the duty cycle, it is possible to set a certain average value of the lamp current, allowing the efficacy and/or color temperature of the lamp to be influenced.
Claims33
Method for driving a gas discharge lamp, specifically a HID lamp, more specifically a metal halide lamp, most specifically a metal halide lamp with an aspect ratio larger than 3 or even 4, wherein the lamp is supplied with a commutating DC current;
- the method comprising the step of generating a light-controlling electric field E with a desired direction and a desired strength inside the lamp to obtain a desirable particle distribution inside the lamp.
Driving apparatus for driving a gas discharge lamp, specifically a HID lamp, more specifically a metal halide lamp, most specifically a metal halide lamp with an aspect ratio larger than 3 or even 4, the apparatus comprising:
- current generating means for generating a current with a substantially constant current intensity;
- commutating means for receiving said current, and having an output for connecting to a lamp, the commutating means being arranged for commutating said current with a duty cycle differing from 50%.
Position detector capable of being associated with a gas discharge lamp or with a lamp holder, and further capable of detecting the actual orientation of the lamp or the lamp holder, respectively, and for generating an output control signal indicative of such orientation.
Gas discharge lamp, specifically a HID lamp, more specifically a metal halide lamp, most specifically a metal halide lamp with an aspect ratio larger than 3 or even 4, the lamp being associated with an orientation detector having at least one output coupled to the control input of the driver;
- the position detector being arranged for detecting the actual orientation of the lamp, and for generating at its output a control signal indicative of such orientation.
Lamp holder for receiving a lamp cap of a lamp assembly, the holder being associated with an orientation detector having at least one output for coupling to a control input of a driver;
- the position detector being arranged for detecting the actual orientation of the lamp, and for generating at its output a control signal indicative of such orientation.
Dependencies are inferred from the claim text.