EP2116111B1 - High-voltage pulse generator and high-pressure discharge lamp comprising such a generator - Google Patents

Abstract

A compact high-voltage pulse generator based on a spiral pulse generator, the spiral pulse generator being in the form of an LTCC component part or HTCC component part including a ceramic film wound in the form of a spiral and metallic conductive paste applied thereto in strip form, wherein the spiral pulse generator acts as a transformer by virtue of a first metallic conductor being rolled up to form a spiral with n turns, where n is at least 5, while in addition a switch and a charging capacitor are connected to the start of the first metallic conductor.

Description

Technical area

The invention relates to a high-voltage pulse generator according to the preamble of claim 1. Such generators can be used in particular for the ignition of high-pressure discharge lamps for general lighting or for photo-optical purposes or for motor vehicles. The invention further relates to a high-pressure discharge lamp with such a generator.

State of the art

The problem of the ignition of high pressure discharge lamps is currently solved by the fact that the ignitor is integrated into the ballast. The disadvantage of this is that the leads must be designed high voltage resistant.

In the past there have always been attempts to integrate the ignition unit into the lamp. They tried to integrate them into the socket. A particularly effective and high pulse promising ignition succeeds by means of so-called spiral pulse generators, see US-A 3,289,015 , Lately, such devices have been proposed in various high pressure discharge lamps, such as metal halide lamps or high pressure sodium lamps, see for example US-A 4,325,004 . US Pat. No. 4,353,012 , However, they could not prevail, because they are too expensive for one. On the other hand, the advantage of installing them in the socket is not sufficient because the problem of supplying the high voltage to the piston remains. Therefore the likelihood of damage to the lamp, whether insulation problems or a breakthrough in the socket, increases sharply. Previously common igniters could not be heated above 100 ° C in general. The voltage generated then had to be fed to the lamp, which requires leads and lampholders with appropriate high voltage resistance, typically about 5 kV.

To generate particularly high voltages, a double generator can be used, see US Pat. No. 4,608,521 ,

Presentation of the invention

The object of the present invention is to provide a spiral pulse generator which can be used as a high temperature resistant transformer.

This object is achieved by the characterizing features of claims 1 and 2.

A further object is to provide a high-pressure discharge lamp whose ignition behavior is significantly improved compared to previous lamps and in which no damage due to the high voltage is to be feared. This applies in particular to metal halide lamps, wherein the material of the discharge vessel can be either quartz glass or ceramic.

This object is achieved by the characterizing features of claims 9 and 14.

Particularly advantageous embodiments can be found in the dependent claims.

From DE-Az 102005061832.4 and 102005061831.6 a compact high voltage pulse generator is known, which can generate high voltages above 15 kV. The spiral pulse generators generally consist of two conductors of approximately equal length wound up as a spiral, see FIG. 1 , This means that each conductor has approximately the same number of turns. Such a structure is required to use the vector inversion principle.

From DE-Az 102006026750.8 it is known to use a spiral pulse generator, which is surrounded by a ferritic material having a relative permeability of μ _r = 1 to 5000. These three documents are expressly incorporated by reference. In this case, the principle is always exploited that a current flowing as a result of the short circuit in the first turn current induces a high voltage pulse in the remaining turns.

According to the invention, a significantly different length of the two wound conductors is now used. In this case, the second conductor only a few turns, while the first conductor has the usual number of turns, such as 20 to 100. In this case, the spiral pulse generator acts as a high temperature resistant transformer. This transformer works in a similar way to an integrated Saving Transformer in that the second conductor acts as a capacitor and thus acts as a charging capacitor for the transformer. By shortening the second conductor, either the design can be reduced or the transformer can be designed with the same volume with more turns, resulting in a higher high voltage pulse.

When using a separate conventional charging capacitor, the generator can also be designed with only one conductor winding with three contacts as a real economy transformer.

The spiral pulse generator used now is in particular a so-called. LTCC component or HTCC component. This material is a special ceramic that can be made temperature resistant to 600 ° C. Although LTCC has already been used in connection with lamps, see US 2003/00015199 and US Pat. No. 6,853,151 , However, it has been used for quite different purposes in practically barely temperature loaded lamps, with typical temperatures below 100 ° C. The particular value of the high temperature stability of LTCC associated with the ignition of high pressure discharge lamps, especially metal halide lamps with ignition problems.

In its basic version, the spiral pulse generator is a component that combines the properties of a capacitor with those of a waveguide to produce ignition pulses with a voltage of at least 1.5 kV. Two ceramic "green films" with metallic conductive paste are used for the production printed and then added to a spiral wound and finally isostatically pressed into a molding. The following co-sintering of metal paste and ceramic film takes place in air in the temperature range between 800 and 900 ° C. This processing allows a range of application of the spiral pulse generator up to 700 ° C temperature load. As a result, the spiral pulse generator can be accommodated in the immediate vicinity of the discharge vessel in the outer bulb, but also in the base or in the immediate vicinity of the lamp. Regardless, such a spiral pulse generator can also be used for other applications, because it is not only high temperature stable, but also extremely compact. For this it is essential that the spiral pulse generator is designed as an LTCC component, consisting of ceramic foils and metallic conductive paste. To provide sufficient output voltage, the spiral should have at least 5 turns.

In addition, based on this high-voltage pulse generator, an ignition unit can be specified which furthermore comprises at least one charging resistor and a switch. The switch can be a spark gap or a Diac in SiC technology.

In the case of an application for lamps, the accommodation in the outer bulb is preferred. Because this eliminates the need for a high voltage resistant voltage supply.

In addition, a spiral pulse generator can be dimensioned so that the high-voltage pulse even allows a hot re-ignition of the lamp. The ceramic dielectric is characterized by an exceptionally high dielectric constant ε of ε> 10, whereby, depending on the material and construction, an ε of typically 70, up to ε = 100, can be achieved. This creates a very high capacity of the spiral pulse generator and allows a comparatively large time width of the generated pulses. As a result, a very compact design of the spiral pulse generator is possible, so that an installation in commercial outer bulb of high-pressure discharge lamps succeed. Furthermore, the generated high voltage pulse represents a comparatively large energy available, which facilitates the transition to self-discharge after successful breakdown.

The large pulse width also facilitates the breakdown in the discharge volume.

As the material of the outer bulb of a lamp, any conventional glass can be used, ie in particular tempered glass, Vycor or quartz glass. The choice of filling is subject to no particular restriction.

Brief description of the drawings

Fig. 1

den prinzipiellen Aufbau eines Spiral-Puls- Generators wie bereits bekannt;

Fig. 2

den prinzipiellen Aufbau eines Spiral-Puls- Generators mit ferritischer Umfüllung;

Fig. 3

den prinzipiellen Aufbau eines Spiral-Puls- Generators mit verkürztem zweiten Leiter ;

Fig. 4

den prinzipiellen Aufbau eines Spiral-Puls- Generators mit nur einem metallischen Leiter;

Fig.

5 den Prinzipaufbau einer Metallhalogenidlampe mit Spiral-Puls-Generator im Außenkolben.

Fig. 6

eine Metallhalogenidlampe mit Spiral-Puls- Generator im Außenkolben;

Fig. 7

eine Metallhalogenidlampe mit Spiral-Puls- Generator im Sockel.

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

Fig. 1

the basic structure of a spiral pulse generator as already known;

Fig. 2

the basic structure of a spiral pulse generator with ferritic transfer;

Fig. 3

the basic structure of a spiral pulse generator with shortened second conductor;

Fig. 4

the basic structure of a spiral pulse generator with only one metallic conductor;

FIG.

5 shows the basic structure of a metal halide lamp with spiral pulse generator in the outer bulb.

Fig. 6

a metal halide lamp with spiral pulse generator in the outer bulb;

Fig. 7

a metal halide lamp with spiral pulse generator in the base.

Preferred embodiment of the invention

FIG. 1 shows the basic structure of a spiral pulse generator 1 in plan view. It consists of a ceramic cylinder 2, in which two different metallic conductors 3 and 4 are spirally wrapped as a film strip. The cylinder 2 is hollow inside and has a given inner diameter ID. The two inner contacts 6 and 7 of the two conductors 3 and 4 are as close to each other as possible and are connected to each other via a spark gap 5.

Only the outer of the two conductors has on the outer edge of the cylinder another contact 8. The other conductor ends open. The two conductors together thereby form a waveguide in a dielectric medium, the ceramic.

The spiral pulse generator is either wound from two ceramic paste-coated ceramic foils or built up from two metal foils and two ceramic foils. An important parameter is the number n of turns, which should preferably be in the order of 5 to 100. This winding assembly is then laminated and then sintered, creating an LTCC component. The thus created spiral pulse generators with capacitor property are then connected with a spark gap and a charging resistor.

The spark gap can be at the inner or the outer terminals or even within the winding of the generator are located. As a high-voltage switch, which initiates the pulse, a spark gap can preferably be used, which is temperature-stable. It is also possible to use a semiconductor switching element, preferably in SiC technology. This is suitable for temperatures above 350 ° C.

In a concrete embodiment, a ceramic material with ε = 60 to 70 is used. In this case, a ceramic film, in particular a ceramic tape such as Heratape CT 707 or preferably CT 765 or a mixture of both, respectively from Heraeus, is preferably used as the dielectric. It has a thickness of the green film of typically 50 to 150 microns. In particular, Ag conductive paste such as "Cofirable Silver", also from Heraeus, is used as the conductor. A concrete example is TC 7303 from Heraeus. Good results are also provided by the metal paste 6145 from DuPont. These parts are easy to laminate and then heat out ("binder burnout") and sinter together ("co-firing").

In one embodiment, the inner diameter ID of the spiral pulse generator is 10 mm. The width of the individual strips is also 10 mm. The film thickness is 50 μm and also the thickness of the two conductors is 50 μm in each case. The charging voltage is 300 V. Under these conditions, the spiral pulse generator achieves its optimum properties with a number of turns of n = 20 to 70.

The generator is comprised of a ferritic EI core with a permeability of μ = 50 ... 5000, as shown in Fig. As a result, it is operated as a transformer and not according to the principle of vector inversion. Advantageously, the generator 1 is wholly or partially surrounded by a ferritic material 50 having a permeability of μ = 50 to 5000. In FIG. 2 a ferrite 50 is shown in E-core shape, the center bar 51 passes through the inner cavity of the generator 1.

• Figur 4 zeigt einen Spiralpulsgenerator 20, der überhaupt nur einen einzigen metallischen Leiter 3 besitzt. Er weist jetzt einen separaten handelsüblichen Ladekondensator 10 auf, der mit der Funkenstrecke 5 in Serie geschaltet ist. Diese Schaltung wirkt als Spar-Transformator, indem ein Mittenabgriff 40 des metallischen Leiters über den Ladekondensator 10 und die Funkenstrecke 5 mit dem inneren Ende 41 des metallischen Leiters verbunden ist.
• Figur 5 zeigt den prinzipiellen Aufbau einer Metallhalogenidlampe 25 mit integriertem Spiral-Puls-Generator 21, wobei keine Zünd-Elektrode außen am Entladungsgefäß 22, das aus Quarzglas oder Keramik gefertigt sein kann, angebracht ist. Der Spiral-Puls-Generator 21 ist mit der Funkenstrecke 23 und dem Ladewiderstand 24 im Außenkolben 36 untergebracht.
• Figur 6 zeigt eine Metallhalogenidlampe 25 mit einem Entladungsgefäß 22, das von zwei Zuleitungen 26, 27 in einem Außenkolben gehaltert wird. Die erste Zuleitung 26 ist ein kurz abgewinkelter Draht. Die zweite 27 ist im wesentlichen ein Stab, der zur sockelfernen Durchführung 28 führt. Zwischen der Zuleitung 29 aus dem Sockel 30 und dem Stab 27 ist eine Zündeinheit 31 angeordnet, die den Spiral-Puls-Generator, die Funkenstrecke und den Ladewiderstand enthält, wie in Figur 5 angedeutet.
• Figur 7 zeigt eine Metallhalogenidlampe 25 ähnlich wie Figur 5 mit einem Entladungsgefäß 22, das von zwei Zuleitungen 26, 27 in einem Außenkolben 36 gehaltert wird. Die erste Zuleitung 26 ist ein kurz abgewinkelter Draht. Die zweite 27 ist im wesentlichen ein Stab, der zur sockelfernen Durchführung 28 führt. Hier ist die Zündeinheit im Sockel 30 angeordnet, und zwar sowohl der Spiral-Puls-Generator 21, als auch die Funkenstrecke 23 und der Ladewiderstand 24.

In FIG. 3 an inventive Spiralpulsgenerator 10 is shown, in which the second metallic conductor 14 is significantly shorter than the first conductor 3. The second conductor 14 should be at least 5 turns or at least 10% of the number of turns shorter than the first conductor 3, the Winding number is preferably of the order of n = 20 to 100. The contacts of the spark gap 5 may be opposite each other or as close as possible to each other.

• FIG. 4 shows a spiral pulse generator 20 having only a single metallic conductor 3 at all. He now has a separate commercially available charging capacitor 10, which is connected in series with the spark gap 5. This circuit acts as a spar transformer by connecting a center tap 40 of the metallic conductor via the charging capacitor 10 and the spark gap 5 to the inner end 41 of the metallic conductor.
• FIG. 5 shows the basic structure of a metal halide lamp 25 with integrated spiral pulse generator 21, wherein no ignition electrode on the outside of the discharge vessel 22, which may be made of quartz glass or ceramic, is attached. The spiral pulse generator 21 is housed with the spark gap 23 and the charging resistor 24 in the outer bulb 36.
• FIG. 6 shows a metal halide lamp 25 with a discharge vessel 22 which is supported by two supply lines 26, 27 in an outer bulb. The first lead 26 is a short-angled wire. The second 27 is essentially a rod that leads to the socket remote 28 implementation. Between the supply line 29 from the base 30 and the rod 27, an ignition unit 31 is arranged, which contains the spiral pulse generator, the spark gap and the charging resistor, as in FIG. 5 indicated.
• FIG. 7 shows a metal halide lamp 25 similar to FIG. 5 with a discharge vessel 22, which is supported by two supply lines 26, 27 in an outer bulb 36. The first lead 26 is a short-angled wire. The second 27 is essentially a rod that leads to the socket remote 28 implementation. Here, the ignition unit is arranged in the base 30, both the spiral pulse generator 21, as well as the spark gap 23 and the charging resistor 24th

This technique can also be used for electrodeless lamps, where the spiral pulse generator can serve as a starting aid.

Other applications of this compact high-voltage pulse generator are in the ignition of other devices. The application is particularly advantageous in so-called magic spheres, in the generation of X-ray pulses and in the generation of electron beam pulses. A use in a car as a replacement for the usual ignition coils is possible.

In this case, winding numbers of n to 500 are used, so that the output voltage reaches up to the order of 100 kV. Because the output voltage U _A is as Function of the charging voltage U _L given by U _A = 2 xnx U _L x η, where the efficiency η is given by η = (AD-ID) / AD.

The invention develops particular advantages in cooperation with high-pressure discharge lamps for car headlights, which are filled with xenon under high pressure of preferably at least 3 bar and metal halides. These are particularly difficult to ignite because of the high xenon pressure, the ignition voltage is more than 10 kV. Currently trying to accommodate the components of the ignition unit in the base. A spiral pulse generator with integrated charging resistor can be accommodated in the base of the vehicle lamp.

The invention develops very special advantages in combination with high-pressure discharge lamps which contain no mercury. Such lamps are particularly desirable for environmental reasons. It contains a suitable metal halide fill and, in particular, a noble gas such as xenon under high pressure. Because of the lack of mercury, the ignition voltage is particularly high. It is more than 20 kV. Currently trying to accommodate the components of the ignition unit in the base. A spiral pulse generator with built-in charging resistor can either be housed in the base of the mercury-free lamp or in an outer bulb of the lamp.

Claims (18)

1. Compact high-voltage pulse generator based on a spiral pulse generator, the spiral pulse generator being in the form of an LTCC component part or HTCC component part comprising a ceramic film wound in the form of a spiral and metallic conductive paste applied thereto in strip form, characterized in that the spiral pulse generator acts as a transformer by virtue of a first ceramic film with a first metallic conductor being rolled up to form a spiral with 5 turns, a second metallic conductor being wound on a second ceramic film, which is wound in the form of a spiral, together with the first ceramic film and acting as charging capacitor therewith, but the wound length of the second ceramic film being at least two windings shorter than the wound length of the first ceramic film, while in addition a switch is connected to the inner end of the first and the second conductor.
2. Compact high-voltage pulse generator based on a spiral pulse generator, the spiral pulse generator being in the form of an LTCC component part or HTCC component part comprising a ceramic film wound in the form of a spiral and metallic conductive paste applied thereto in strip form, characterized in that the spiral pulse generator acts as a transformer by virtue of the ceramic film, with the metallic conductor applied thereto, being rolled up to form a spiral with at least 5 turns, the transformer being connected in the form of an autotransformer by virtue of a center tap (40) of the metallic conductor being connected via a charging capacitor (10) and a spark gap (5) to the inner end (41) of the metallic conductor.
3. High-voltage pulse generator according to Claim 1 or 2, characterized in that the spiral comprises at least n = 5 turns and preferably at most n = 500 turns.
4. High-voltage pulse generator according to Claim 1 or 2, characterized in that the generator is entirely or partially surrounded by a ferritic material with a permeability of µ=50...5000.
5. High-voltage pulse generator according to Claim 1 or 2, characterized in that the switch is a spark gap.
6. High-voltage pulse generator according to Claim 2, characterized in that the charging capacitor is a conventional capacitor.
7. High-voltage pulse generator according to Claim 1, characterized in that the number of windings of the second metallic conductor is at least one winding and at most 20% of the number of windings of the first metallic conductor.
8. Starting device based on a spiral pulse generator according to Claim 1, characterized in that the starting device furthermore comprises at least one charging resistor and a switch.
9. High-pressure discharge lamp with a discharge vessel which is accommodated in an outer bulb, a starting device being integrated in the lamp which produces high-voltage pulses in the lamp of at least 15 kV, characterized in that the starting device is accommodated in the outer bulb and comprises a high-voltage pulse generator according to one of the preceding Claims 1 to 7.
10. High-pressure discharge lamp according to Claim 9, characterized in that the starting device is held in the outer bulb by a frame.
11. High-pressure discharge lamp according to Claim 9, characterized in that the high voltage produced by the spiral pulse generator acts directly on two electrodes in the discharge vessel.
12. High-pressure discharge lamp according to Claim 9, characterized in that the voltage produced by the spiral pulse generator acts on an auxiliary starting electrode fitted on the outside of the discharge vessel.
13. High-pressure discharge lamp according to Claim 9, characterized in that, in addition, a series resistor is accommodated in the outer bulb, which series resistor limits the charging current of the spiral pulse generator.
14. High-pressure discharge lamp with a discharge vessel and a base, a starting device being integrated in the lamp which produces high-voltage pulses in the lamp of at least 15 kV, characterized in that the starting device is accommodated in the base of the lamp and comprises a high-voltage pulse generator according to one of the preceding Claims 1 to 7.
15. High-pressure discharge lamp according to Claim 9 or 14, characterized in that the spiral pulse generator comprises a plurality of layers, the number n of layers being at least n = 5.
16. High-pressure discharge lamp according to Claim 15, characterized in that the number n of layers is at most n = 500, preferably at most n = 100.
17. High-pressure discharge lamp according to Claim 9 or 14, characterized in that the spiral pulse generator has an approximately hollow-cylindrical design, with an inner diameter of at least 10 mm.
18. High-pressure discharge lamp according to Claim 9 or 14, characterized in that the dielectric constant ε of the spiral pulse generator is at least ε = 10.

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