The invention relates to a discharge lamp arrangement with a lamp tube in which a noble gas is contained, having two internal electrodes arranged in the tube, and having a secondary ignition electrode which is outside of the tube and is disposed outstretched lengthwise close to its surface.
Such arrangements are disclosed, for example, in EP 0 049 466 A2. In the latter the secondary ignition electrodes required for the operation of the discharge lamps are in the form of a conductor disposed along the discharge lamp, which is mounted either by means of clips at opposite ends of the lamp, or the secondary ignition electrode is mounted on the lamp socket and carried as a wire along the lamp tube. Furthermore, secondary ignition electrodes are explained which are wound spirally or mesh-like around the tubes. These arrangements are relatively complicated to manufacture, for example due to the necessary complicated socket configuration, or due to the complicated arrangement of the ignition electrode directly on the tube. The arrangements described tend, on account of the electromagnetic forces developing during the operation of the discharge lamp, to migrate around the tube, so that the deposits forming during operation of the lamp are not restricted to a small area of the lamp, and instead gradually cause more or less severe darkening over the entire circumference, so that the useful life of the discharge lamps is very limited. This makes the operation of these discharge lamps expensive, not to mention the complication created by the arrangement of the secondary ignition electrodes in manufacturing them.
Similar arrangements are disclosed in DE 37 18216 A1. Such arrangements are used with a noble gas charge (e.g., xenon) also as stroboscope lamps. The secondary ignition electrode is applied in the form of a conductor strip directly on the external surface of the tube. Such an arrangement is subjected to severe thermomechanical stresses. Differences in expansion coefficients between the conductor strip and the light tube can result in damage to the ignition electrode.