Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Osram Sylvania Inc.

Patent-treuhand-gesellschaft Fuer Elektrische Gluehlampen Mbh

Erolf Weinhardt

Roland Hoffmann

Horst Wittmann

Dieter Hofmann

Christian Harzig

Michael Dietrich

Low-pressure discharge lamp having an angularly oriented support member

Method for producing a cap band for discharge lamps

The invention relates to electrode coils for discharge lamps having a coiled wire (1) which is wound around by a braiding wire (2). The coiled wire (1) has both turns (II) with an essentially circular cross-section and turns (I, III) with an oval cross-section. In order to produce the bar-shaped coil according to the invention, the unit comprising the coiled wire (1), the first core wire (3) and the braiding wire (2) is wound around a second core wire (4) which is flattened in places. Unrolling of the braiding wire (2) is prevented thereby. Production of the coil is cost-effective, since only two core wires are required and the coil ends are not fused.

Electrode coil for discharge lamps and method for producing such an

The lifetime of cold-start fluorescent lamps is increased, and the ability to withstand repeated ON-OFF switching cycles enhanced by coating the electrodes with an emitter which consists of barium oxide and a small portion of metallic barium and, optionally, up to 20 mol-% of strontium oxide and a small portion of metallic strontium, preferably only up to about 5 mol-% of strontium oxide--metallic strontium. To make the emitter, barium carbonate, optionally mixed with strontium carbonate, is applied in paste form to the electrodes which, when coated, are introduced into an envelope and sealed therein. The envelope is then evacuated, and the electrodes are heated, thus converting the barium carbonate to barium oxide and metallic barium, and the strontium carbonate, if present, to strontium oxide and metallic strontium, so that the electrodes will be coated with barium oxide, optionally strontium oxide, and metallic barium and optionally metallic strontium. The evacuation and activating step can be carried out essentially simultaneously, by evacuating the envelope through a pump tube and heating the electrodes to above about 800.degree. C. by passing a current pulse therethrough.

Discharge lamp, particularly cold-start fluorescent lamp, and method of

To improve mass production of fluorescent lamps, and introduction of merc within the interior thereof, the lamp mount includes an electrically conductive strip, band or wire secured within the vessel, to which a heater wire (11, 31, 40) is connected, the heater wire being melt-connected to extend into the glass capsule, forming therein a narrow V, or U-shaped structure. Upon application of a high frequency field, the heater wire will heat and open the glass capsule in the region of the melt-through connection thereof, thus liberating mercury previously introduced into the glass capsule, for example in the form of a drop, a pellet of porous substance with mercury dispersed therein, or the like.

Mercury discharge lamp with mercury containing capsule

The amount of emitter paste which can be applied to the filament used in orescent tubes can be increased by winding the filament, as previously proposed, about an iron or molybdenum mandrel which can be dissolved; in contrast to the prior art, however, the wound filament is not annealed at a temperature which removes winding stresses but, rather, at a lower temperature of about for example 900.degree. C. for tungsten wire, thus retaining some of the winding stresses. Upon dissolving-out of the iron core or mandrel, the remaining stresses will cause adjacent windings of the filament to slightly relieve their stresses by springing back to some extent, resulting in relatively offset end portions of the wires with respect to each other, when the wires have been wound on a mandrel which has an essentially rectangular cross section in which the ratio of length to width--in cross section--is greater than 2. The resulting surface roughness of an envelope of the filament permits retention of a larger amount of emitter material with better retention capabilities, and thus increases the lifetime of lamps by about 30% with respect to lamps having filaments in which adjacent windings are congruent.

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Diedorf, Germany

Erolf Weinhardt