Method to operate an incoherently emitting radiation source having at least one dielectrically impeded electrode

A method to operate an incoherently emitting radiation source, in particular a discharge lamp (1), from an electrical energy supply (10, 11, 12), by means of an electrically impeded discharge,

• wherein said radiation source comprises
• an at least partially transparent discharge vessel (2) of electrically nonconductive material;
• a gas filling (5) inside the vessel;
• at least two electrodes (3, 4) mounted in the vicinity of the gas filling (5);
• supply lines connecting said electrodes (3, 4) to the electrical energy supply (10-12);
• and
• a dielectric layer disposed between at least one electrode (4) and the gas filling (5),
• said method, in accordance with the invention, comprising
• causing the electrical energy supply (10-12) to furnish energy between the electrodes (3, 4) in the form of a train of voltage pulses having characteristic parameters,
• wherein any individual pulse (n) of the train has a voltage parameter U.sub.Pn (t) and a pulse duration parameter T.sub.Pn, which pulse duration parameter is of the order of magnitude of approximately 1 ns to 5 .mu.s;
• wherein each pulse (n) is separated from its successor pulse (n+1) by an idle time parameter of duration T.sub.0n, which idle time is in the order of magnitude of approximately 500 ns to 1 ms and with an idle time voltage parameter of U.sub.0n (t);
• introducing, during the pulse duration T.sub.Pn, predominantly electrical effective power into the gas filling (5) by controlling the voltage U.sub.Pn (t) of said voltage pulse during said pulse duration;
• causing, during the idle time T.sub.0n duration, the voltage U.sub.0n (t) to be at a level to permit the gas filling (5) to revert to a state which is similar to the state of said gas filling prior to the particular preceding voltage pulse U.sub.Pn (t);
• and
• controlling the parameters of the variables
• pulse voltage level U.sub.Pn (t),
• pulse time duration T.sub.Pn,
• voltage during idle time U.sub.0n (t),
• idle time duration T.sub.0n,
• mutually relative to one another such that, between the electrodes (3, 4), discharge structures of comparatively low current densities are created.