EP2483913B1 - High pressure discharge lamp having a starting aid - Google Patents

Description

Technical area

The invention relates to a high-pressure discharge lamp according to the preamble of claim 1. Such lamps are in particular high-pressure discharge lamps for general lighting or for photo-optical purposes.

State of the art

From the US 6,268,698 is a high-pressure discharge lamp with discharge vessel is known, in which a starting aid emanating from a long frame wire. The ignition aid is a separate component which extends in the direction of the discharge vessel at the level of a capillary.
A disadvantage of such an arrangement is that the ignition must be installed consuming and costly. From the US2004 / 227445 is a high-pressure discharge lamp is known in which a film wraps around the capillary. In this case, one end of the film is connected to a hanger wire by welding. Similar things can be found in the US 2004/036416 , US 4 053 809 discloses a high pressure discharge lamp having the features of the preamble of claim 1.

Presentation of the invention

The object of the present invention is to provide a high-pressure discharge lamp whose ignition is ensured by simple inexpensive means. This applies according to the invention for metal halide lamps, wherein the material of the discharge vessel is ceramic.
This object is achieved by the characterizing features of claim 1.
Particularly advantageous embodiments can be found in the dependent claims.

According to the invention, a separate component is now used on the frame, which extends in the direction of a capillary. The component is connected to the long power supply, the so-called. Stirrup wire of the frame, and preferably in an area in the vicinity of the capillary, in particular where the electrode is seated in the capillary, but is spaced from the wall of the capillary.

As the service life increases, the voltage required to ignite high pressure discharge lamps increases. This can result in old lamps not starting on conventional ignitors. However, the ignitability must be guaranteed over the entire lifetime, which is ensured by the arrangement according to the invention, without significant additional costs.

• a) Dem Brennerfüllgas wird ein radioaktives Gas, beispielsweise Kr85, beigemischt. Die Radioaktivität bewirkt eine Ionisierung des Füllgases, welche die Durchschlagsspannung herabsetzt und so die Zündfähigkeit sicherstellt. Jedoch wird der Gebrauch von Radioaktivität gesetzestechnisch zunehmend eingeschränkt.
• b) Im Außenkolben wird ein sog. UV-Enhancer eingebaut. Dieser besteht aus einer miniaturisierten Entladungsröhre, die beim Anlegen der Zündspannung UV-Strahlung emittiert. Diese UV-Strahlung bewirkt ebenfalls eine Ionisierung des Brennerfüllgases und stellt so die Zündfähigkeit sicher, siehe EP-A 922296 .
• c) Vom Bügeldraht wird ein Draht um die Kapillare mit der gegenpoligen Elektrode gewickelt. Beim Anlegen der Zündspannung entsteht so im Bereich dieser Elektrode eine dielektrisch behinderte Entladung, welche das Brennerfüllgas ionisiert und die Zündspannung herabsetzt, siehe z.B. EP-A 967631 .

So far, there have been various approaches to this.

• a) The radioactive gas is a radioactive gas, such as Kr85, admixed. The radioactivity causes an ionization of the filling gas, which reduces the breakdown voltage and thus ensures the ignitability. However, the use of radioactivity is increasingly limited by law.
• b) A so-called UV enhancer is installed in the outer bulb. This consists of a miniaturized discharge tube, which emits UV radiation when the ignition voltage is applied. This UV radiation also causes ionization of the Brennerfüllgases and thus ensures the ignitability, see EP-A 922296 ,
• c) From the hanger wire, a wire is wound around the capillary with the opposite pole electrode. When applying the ignition voltage Thus arises in the range of this electrode a dielectrically impeded discharge, which ionizes the Brennerfüllgas and reduces the ignition voltage, see, for example EP-A 967631 ,

The current arrangement takes up the principle of dielectrically impeded discharge, but improves it decisively.

The hanger wire is designed so that an ignition aid from there as close as possible to the capillary with the opposite pole electrode or touches them. There arises, similar to the wire windings mentioned under c), a dielectric barrier discharge, which ionizes the filling gas in the burner and allows a breakdown. Characteristic of the approach is that in contrast to previous solutions, the ignition aid is a plate-like metal part. The metal part is a pre-bent spring part, in particular a film or a sheet metal part. A typical size for foil or sheet metal part is a rectangle with a dimension of 1 mm x 10 mm.

According to the invention, a metal part, e.g. a metal foil, preferably made of molybdenum or tungsten, mechanically attached, which contacts the capillary with the electrode with the opposite potential. There arises, similar to the wire windings mentioned under c), a dielectric barrier discharge, which ionizes the filling gas in the burner and allows a breakdown.

Characteristic of this approach is the use of a flexible film, which always contact due to their compliance with the capillary of the discharge vessel Has. For this purpose, the film must be very thin, in any case thinner than 200 microns, preferably between 20 microns and 40 microns. The film has no mechanical support. It covers the capillary over a large area.

The film can partially or completely cover the capillary or loop around the capillary. Preferred is a simple geometry that does not affect the production.

The foil is attached to the stirrup wire either by a material fit (eg by welding) or by a force fit (eg by clamping or crimping).

The ignition aid preferably has a minimum distance to the opposite pole current-carrying electrode, wherein the location of the smallest distance should be as close as possible to the actual discharge vessel.

There are according to the invention no more radioactive admixtures needed. A guided on the capillary film is manufacturing technology very easy to implement in one-capped lamps and much easier than a wire wrapping the capillary. In addition, unlike UV enhancers, the film requires little additional space in outer bulbs. The risk that the ignition aid loses its functionality or position during the service life due to a poor joint connection to the hanger wire, is practically not given, since a film can be attached over a relatively large area.

A film attached to the capillary is very easy to realize in terms of manufacturing technology in single-ended lamps; much easier than a wire wrap the capillary. In addition, unlike UV enhancers, this film does not require extra space in outer bulbs.

The film may also be coated or doped.

A film can be kinked well and still remains dimensionally stable thereafter. However, it can also be obtained dimensionally stable by skillful suitable arrangement.

The hanger wire and the capillary with the opposite pole electrode are in particular connected by a metal clip. This clip causes, as explained above, a dielectrically impeded discharge, which reduces the ignition voltage. The clip preferably consists of a pre-bent metal foil. The shape is chosen so that the clip rests tightly by prestressing tightly on the capillary and / or the hanger wire.

• Erstes Ausführungsbeispiel: Der Clip wird auf die Kapillare aufgesteckt (Fig 1b-c), wo er durch seine Vorspannung stabil aufliegt. Dabei muss das vorgebogene Metallteil einen Durchmesser aufweisen, der kleiner ist als der Außendurchmesser der Kapillare. Der Durchmesser sollte 70% - 90% des Kapillardurchmessers betragen. Die Verbindung mit dem Bügeldraht muss auf andere Weise erfolgen, z.B. durch Schweißen oder Crimpen.

There are several ways to attach the clip:

• First embodiment: The clip is attached to the capillary ( Fig 1b-c ), where it rests stable by its bias. In this case, the pre-bent metal part must have a diameter which is smaller than the outer diameter of the capillary. The diameter should be 70% - 90% of the capillary diameter. The connection with the stirrup wire must be made in other ways, eg by welding or crimping.

Second embodiment: The clip is attached to the hanger wire. Again, the preforming must have a smaller diameter than the hanger wire, ideally between 70% and 90%. The clip must be attached to the capillary. This can be done by joining the metal foils on the opposite side of the hanger wire, e.g. by welding or crimping.

The clip can be made from any heat resistant and electrically conductive material. Tried and tested is the production of molybdenum, and other materials such as various steels are conceivable.

Special advantages are: No more radioactive admixtures are needed. In contrast to UV enhancers, the clip does not require any additional space in outer bulbs. The realization of the production is very simple, since in the case of one-sided clips only one more connection, eg welding point, with two-sided clips no further connection technology is needed. The mechanical contact is always given by the bias of the clip.

Instead of the clip being welded to the hanger wire, basically any other form of permanent fixation is possible.

Brief description of the drawings

Fig. 1

eine Hochdruckentladungslampe mit Zündhilfe, erstes Ausführungsbeispiel in drei Details, siehe Figur 1a bis 1d;

Fig. 2

eine Hochdruckentladungslampe mit Zündhilfe, zweites Ausführungsbeispiel in drei Details, siehe Figur 2a bis 2c;

Fig. 3

eine Hochdruckentladungslampe mit Zündhilfe, in zwei Details, siehe Figur 3a bis 3b;

Fig. 4

eine Hochdruckentladungslampe mit Zündhilfe, in zwei Details, siehe Figur 4a bis 4b.

In the following, the invention will be explained in more detail with reference to several embodiments. The figures show:

Fig. 1

a high-pressure discharge lamp with starting aid, first embodiment in three details, see Figure 1a to 1d;

Fig. 2

a high-pressure discharge lamp with starting aid, second exemplary embodiment in three details, see FIGS. 2a to 2c;

Fig. 3

a high-pressure discharge lamp with ignition aid, in two details, see Figures 3a to 3b;

Fig. 4

a high-pressure discharge lamp with ignition aid, in two details, see Figure 4a to 4b.

Preferred embodiment of the invention

FIG. 1 shows the structure of a high pressure discharge lamp 1 highly schematic. According to Figure 1d it has a discharge vessel 2, which are housed in an outer bulb 3. The outer feeds 4 of the discharge vessel, contacting the electrodes inside are connected to two frame wires 5 and 6. A short frame wire 5 leads to a first foil 7 in a pinch 8 of the outer bulb. A long frame wire 6, often called a stirrup wire, leads to a second film 7 in the pinch 8. The discharge vessel 2 has at its ends in each case a capillary 10, as known per se, and a filling containing metal halides, as also known per se , It can contain Hg, as well as noble gas. Two electrodes are located in the interior of the discharge vessel, as also known per se, but not shown here.

The hanger wire 6 is guided substantially parallel to the axis A of the discharge vessel at this to the second capillary 10 remote from the pinch seal 8 where it is connected to the feed 4.

In the region of the first capillary 10, a film 11 is fastened in the direction of the stirrup wire, which is cut out approximately rectangularly. The end 12 of the film extends to the hanger wire 6 and can survive something there.

In detail shows FIG. 1a the pre-bent foil 69 prior to attachment to the discharge vessel. It has a shape similar to a letter clip with a central pitch arc 70, which encloses a circumference of more than 270 °. At the bow portion 70, two initially free legs 71 follow, which are slightly spread apart from each other. These legs are so long that they bridge the distance between capillary and hanger wire.

FIG. 1b shows a detail of the frame with the capillary 10. The film 69 is pushed onto the capillary 10, so that the arch part 70 includes the capillary 10. The free legs point roughly in the direction of the hanger wire, which sits in the middle between the thighs.

Figure 1c shows that the free legs 71 are then fixed to the hanger wire 6. They are pressed together and welded to the hanger wire 6, so that the finished fixed ignition aid 11 is formed.

In FIG. 2 an embodiment is shown which is similar to FIG. 1 is constructed. However, here the film 69 is not bent symmetrically in the manner of a letter clip, but bent asymmetrically on one side in the manner of a German "ß". The film 69 thus has a straight leg portion 74, from which tangentially an arch portion 75 is bent. The bow part is returned in a circular shape and then bent in the direction of a leg 76. This is compared to the straight leg portion 74 slightly spread outwards, but almost parallel to this. Similar to in FIG. 1 the film 69 is placed on the capillary, so that the hanger wire 6 comes to rest between the two legs 74 and 76, see FIG. 2b , Then, the two legs 74 and 76 are compressed so that both touch the hanger wire 6 from two sides. Then they are welded to the hanger wire 6, so that the finished ignition aid 11 is formed.

FIG. 3 shows a further example of a pre-bent film 80 not belonging to the claimed invention. This has a flat main body 79, which is rolled up at both ends. At a first end 81 is a first pitch arc with a large radius pre-bent. This radius is adapted to the outer diameter of the capillary. At a second end 82, a second partial arc with a smaller radius is pre-bent. This radius is adapted to the hanger wire diameter suitable. This film 80 can be hooked simultaneously to the capillary 10 and the hanger wire 6, see FIG. 3b and then subsequently welded to the hanger wire 6. Possibly. The purely mechanical fixation is already sufficient, so that welding is not necessary.

FIG. 4 shows another example of a pre-bent film 80 not belonging to the claimed invention. Here is the basic structure of the film, see FIG. 4a , similar to in FIG. 3 , However, the actual film body is not exclusively a flat surface 85 as in FIG. 3 but a considerable part 86, preferably 20 to 80% of the length of the main body 79, is corrugated like a concertina. The main body 79 is rolled again at both ends. At a first end 81, a first arc of a large radius is pre-bent. This radius is adapted to the outer diameter of the capillary. At a second end 82, a second partial arc with a smaller radius is pre-bent. This radius is adapted to the hanger wire diameter suitable. This film 80 can be hooked simultaneously to the capillary 10 and the hanger wire 6, see FIG. 4b , and then, if necessary, then welded to the hanger wire.

Claims (5)

1. High-pressure discharge lamp (1) comprising a starting aid and a longitudinal axis (A), comprising a discharge vessel (2) and an outer bulb (3), in which the discharge vessel (2) is accommodated, wherein the discharge vessel has two ends with capillaries (10), in which electrodes are fastened, wherein a frame with bow-shaped wire (6) holds the discharge vessel in the outer bulb, wherein the bow-shaped wire (6) has a starting aid (69) towards the capillary of the opposite-pole electrode, which is not connected thereto, said starting aid being in the form of a plate-like metal part, wherein the plate-like metal part is fastened purely mechanically at least on the capillary, wherein the plane of the plate-like metal part is arranged axially parallel, wherein the metal part is a pre-bent spring part and has a partial circular arc (70; 75) as central part, with the result that the spring part is pushed onto the capillary and surrounds the capillary, characterized in that two limbs (71; 74, 76) of the metal part with free ends (12) extend from the central part at least as far as the opposite sides of the bow-shaped wire and are connected there to the bow-shaped wire (6), and in that the discharge vessel (2) is ceramic.
2. High-pressure discharge lamp according to Claim 1, further characterized in that at least one end of the starting aid is connected to the bow-shaped wire by means of welding.
3. High-pressure discharge lamp according to Claim 1, further characterized in that the starting aid (69) is configured to be symmetrical in the manner of a letter clip.
4. High-pressure discharge lamp according to Claim 1, further characterized in that the starting aid (69) is configured to be asymmetrical and has a partial circular arc (75) as central part, which rests tangentially on a straight first limb (74), while the second limb (76) is bent back.
5. High-pressure discharge lamp according to Claim 1, further characterized in that the discharge vessel has a metal halide fill.

Images