EP2341512B1 - Integrated discharge lamp - Google Patents

Description

description

The present invention relates to a light source with a gas discharge lamp. The light source comprises a control module with a driver circuit, an ignition module for generating a high voltage and a gas-filled burner, in which an arc is ignited and maintained between two electrodes. The invention also relates to a lighting device for a motor vehicle with such a light source.

A light source of the type mentioned is for example from the WO 2004/083900 A1 , of the EP 1 273 848 A1 or the WO 2004/084250 A1 known. In one of the gas discharge lamps described therein, a noble gas or a gas mixture is contained in a burner, which can also be referred to as a discharge vessel or inner bulb. Between two protruding into the interior of the burner electrodes is a voltage is applied so that an arc is formed between the electrodes, which leads to a light emission, and the arc can be maintained during the operation of the light source. In this case, a driver circuit of a control module or a control unit of the gas discharge lamp from the battery voltage of 12 V or 24 V generates an intermediate voltage of a few 100 V to over 1000 V, for example. About 1200 V, between two potentials of -700 V and +500 V. issue. From this intermediate voltage then an ignition module of the gas discharge lamp generates an ignition voltage (high voltage) for the burner, which can be several kilovolts, for example in the range between 10 kV and 25 kV, in particular in the range of 23 kV. To ignite the arc, the ignition voltage is applied to the electrodes. After ignition of the arc, the voltage applied to the electrodes can be reduced to an operating voltage (AC) of only a few volts, for example to a voltage of 43 V or 85 V at 400 Hz. The operating voltage is supplied by a driver circuit of the control module. The ignition voltage is preferably generated by stepping up the operating voltage.

In the light sources known from the prior art, the control module is arranged separately and spatially separated from the burner. The ignition module is integrated in the known light sources either in the control module or arranged directly on the burner and / or a base of the gas discharge lamp. The operating voltage generated by the control module is conducted via a shielded line to the burner or to the ignition module and applied to the electrodes. The decentralized arrangement of the control module has in the known gas discharge lamps especially thermal reasons. Thus, the driver circuit formed in the control module comprises a plurality of electronic components which generate a considerable amount of heat during operation of the light source. This can be better dissipated at a distance to the burner, at lower ambient temperatures. The ignited and maintained in the interior of the burner arc generated very high temperatures, which are in the range of several 100 ° C and can even reach 1,000 ° C or more. These high temperatures would lead to impairment or even damage to the driver circuit or their electronic components, if the control module would be located in close proximity to the burner.

A disadvantage of the known light sources, however, is the relatively large space requirement due to the separate and spatially separated from the rest of the light source control module. In addition, the required shielded connection line between the control module and the remaining light source (burner or ignition module) for additional costs and increased effort during assembly. Due to the transmitted via the connecting line AC signals and the electromagnetic radiation caused thereby, it is necessary that the connecting line is well shielded against electromagnetic radiation. This is done, for example, by a metal mesh or metal-plastic braid surrounding the connecting line. However, this braid must meet a variety of requirements, which leads to relatively high costs for the shielded connection line. If, for example, the light source is part of a movable light module, the mesh must be designed to be flexible so that a relative movement of the burner relative to the light source Control module through the shielded connection line is not or not significantly affected. Otherwise, a reliable movement, in particular a uniform movement, of the light module can not be ensured or it requires particularly strong forces and particularly large and heavy drive units.

Based on the described prior art, the present invention has the object, a light source comprising a gas discharge lamp compact as possible, small-sized, easy to handle and inexpensive to design.

To solve this problem is proposed starting from the light source of the type mentioned that the control module, the ignition module and the burner are mounted on a common carrier system and combined into one unit.

According to the present invention, therefore, contrary to the previous practice, the control module in the vicinity of the burner, namely arranged on a common carrier system of the light source. This is possible because the gas discharge lamp has a lower power and thus also a lower heat development during operation than conventional gas discharge lamps previously used in motor vehicle lighting devices. Preferably, the gas discharge lamp of the light source according to the invention has a reduced by about 20% to 30% compared to conventional gas discharge lamps electrical power. For example, assuming that conventional gas discharge lamps have a power of 35 watts, the gas discharge lamp of the light source according to the invention has a power of about 25 watts, for example. The reduced power results in lower arc temperatures, significantly less waste heat, and the power loss of the control module also decreases.

The reduced luminous flux due to the reduced power does not necessarily lead to a poorer illumination of the road or other areas in front of the motor vehicle. Rather, it is possible to achieve an illumination comparable to more powerful conventional gas discharge lamps by optimizing the other components of the motor vehicle lighting device equipped with the power-reduced gas discharge lamp. The components of the illumination device to be optimized include, for example, a primary optic (for example a reflector), a secondary optic (for example a projection lens), a cover plate of a housing and any other components of the illumination device influencing the light distribution.

Quite decisive for the present invention is the fact that the reduced power of the gas discharge lamp causes the gas discharge lamp to generate significantly less waste heat during operation than conventional gas discharge lamps. Only then is it possible to fasten the control module in the vicinity of the burner to a common carrier system without the control module or its driver circuit or the electronic components being restricted in their function or even being damaged.

An advantage of the light source according to the invention is that no separate, separate from the rest of the gas discharge lamp control module, for example in the form of a Control unit with its own control unit housing, is present, which must be arranged in the vehicle. In addition, by combining the control module, ignition module and burner to form a common unit, the connecting lines between the control module and the burner or ignition module. Finally, it is possible to handle the light source separately as a single unit, thereby substantially facilitating the transportation and installation of the light source in a motor vehicle lighting device according to the invention.

The individual modules of the light source, namely control module, ignition module and burner, can be manufactured as separate modules and tested individually. In the final manufacturing process, all modules are then mounted in or on the common carrier system. In this way, it would also be possible, for example, to combine different modules to different light sources for different applications and customer requirements, without each requiring a complete redevelopment of a light source. Instead, a new light source can be assembled from proven modules that have already been individually tested. This can significantly reduce development time and costs.

According to an advantageous development of the present invention, it is proposed that the carrier system comprises a housing, in particular a metal housing. The housing is preferably made of a metal sheet, in particular an aluminum sheet, bent or as a metal die-cast housing, in particular die-cast aluminum, formed. According to this embodiment of the invention, the control module and the ignition module are in a common housing of the carrier system arranged. The burner would be attached to the housing via the ignition module, with leads or wires connecting the electrodes of the burner to the interior of the housing and the control module or ignition module disposed therein. In addition to the task of fastening the subcomponents of the light source, the housing can also fulfill the functions of protection against moisture, dirt and mechanical stress, heat dissipation (cooling or cooling) and EMC shielding. According to this development, the carrier system thus not only serves to attach the control module, ignition module and burner, but at the same time as a housing, heat sink and EMC shielding.

According to a preferred embodiment of the present invention, it is proposed that the housing has means for increasing a heat release to the environment. For this purpose, the housing may, for example, be equipped with cooling fins or cooling pins or other elements which increase the surface which can be used for heat dissipation. Advantageously, the surface of the housing has a high emissivity of, for example,> 0.7, in particular of> 0.9. The emissivity of a body indicates how much radiation it emits in comparison to an ideal heat radiator, a so-called black body. There are different emissivities, such as a directional spectral emissivity, a hemispherical spectral emissivity, a directional total emissivity, or a hemispherical total emissivity. According to the present invention, emissivity is understood to mean the total hemispheric emissivity. This is according to the present embodiment above 0.7, in particular above 0.9. The emissivity of the housing can by a suitable surface treatment can be improved. To improve the emissivity of the housing, this can be painted with suitable paints, for example. The paints should behave in the infrared wavelength range ideally as a "black spotlight", the paints should therefore absorb the heat radiation as completely as possible and release it to the environment. Decisive in this embodiment is that the emissivity of the surface of the housing by suitable treatment is greater than the corresponding untreated surface (base material). Untreated, aluminum has an emissivity of approx. 0.15. Depending on the design of the housing and the heat-emitting components arranged therein, an emissivity of approximately 0.7 may already be sufficient, but it is preferably above 0.9.

From a thermal point of view, it is particularly advantageous to arrange such modules of the light source in the upper region of the carrier system, which can endure high temperatures without impairment of function or the risk of damage. For example, it would be conceivable to arrange the ignition module or the electrical circuit of the ignition module at the top of the carrier system. Modules that can not be subjected to high thermal loads should be mounted as low as possible on the carrier system. For example, a plug of the control module or ignition module should be arranged as far down as possible on the carrier system. The plug can also be arranged outside the housing.

The present invention also includes automotive lighting devices having at least one light source according to the invention. The lighting device is preferably as a motor vehicle headlight educated.

Figur 1

eine erfindungsgemäße Beleuchtungseinrichtung für ein Kraftfahrzeug mit einer erfindungsgemäßen Lichtquelle gemäß einer bevorzugten Ausführungsform;

Figur 2

ein Lichtmodul der Beleuchtungseinrichtung aus Figur 1; und

Figur 3

eine erfindungsgemäße Lichtquelle des Lichtmoduls aus Figur 2 bzw. der Beleuchtungseinrichtung aus Figur 1 gemäß einer bevorzugten Ausführungsform.

A preferred embodiment of the present invention will be explained in more detail with reference to the drawing. The components and components described below have the specified features and advantages each individually, that is, without the other components and components of the invention, without this being mentioned in each case each time. Show it:

FIG. 1

an illumination device according to the invention for a motor vehicle with a light source according to the invention according to a preferred embodiment;

FIG. 2

a light module of the illumination device FIG. 1 ; and

FIG. 3

a light source according to the invention of the light module FIG. 2 or the lighting device FIG. 1 according to a preferred embodiment.

In FIG. 1 a lighting device for motor vehicles according to the invention is designated in its entirety by the reference numeral 1. The lighting device 1 is formed in the illustrated embodiment as a motor vehicle headlight. Of course, the lighting device 1 may also be designed as a light or the like. The headlight 1 comprises a housing 2, which is preferably made of plastic. In a light exit direction 3, the headlight housing 2 has a light exit opening, which is closed by a transparent cover 4.
The cover 4 is made of colorless plastic or glass. The disk 4 may be formed as a so-called clear disk without optically effective profiles (for example, prisms). Alternatively, the disc 4 may be provided at least partially with optically effective profiles.

Inside the headlight housing 2, two light modules 5, 6 are arranged in the illustrated embodiment. The light modules 5, 6 are arranged fixed or relative to the housing 2 movable. The light modules 5, 6 are to produce a desired light distribution, such as a low beam, a high beam, a city light, a highway, a motorway light, a fog light, a static or dynamic Kurvenlicht- or any other static and / or or adaptive light distribution formed. The light modules 5, 6 generate the desired light function either alone or in combination with each other by the light module 5 of each individual light module; 6 supplied partial light distributions are superimposed to the desired light distribution. The light modules 5, 6 can be designed as a reflection module and / or as a projection module. Of course, more or less than the two illustrated light modules 5, 6 may be provided in the headlight housing 2.

In FIG. 2 one of the light modules 5, 6 is shown by way of example in detail. The light module 5, 6 off FIG. 2 is designed as a projection module. It comprises a light source 7 which emits electromagnetic radiation, preferably light visible to the human eye. In addition, the light module 5, 6 comprises a primary optics 8 in the form of a reflector for bundling the emitted light. The light source 7 is of the Rear side of the reflector 8 ago introduced into a receiving opening formed in the apex of the reflector 8 and fixed there, for example, bayonet. For fixing the light source 7 to the reflector 8, a lamp base 9 is provided on the light source 7.

The light emitted by the light source 7 and focused by the reflector 8 light is imaged by a secondary optics 10, which is formed for example as a projection lens, on the roadway in front of the motor vehicle. The lens 10 is fixed by means of a lens holder 11 at the front edge of the reflector 8. If the light distribution to be generated by the light module 5, 6 has a horizontal light-dark boundary (for example in the case of a low-beam distribution or a fog light distribution), a diaphragm arrangement 12 is arranged between the primary optics 8 and the secondary optics 10, the upper edge 13 of which is projected from the projection lens 10 as a light-dark boundary Roadway is projected in front of the motor vehicle. The course of the upper edge 13 of the diaphragm arrangement 12 can be varied to produce a variable or adaptive light distribution. Likewise, it is conceivable that the diaphragm arrangement 12 in its entirety is pivotable about an axis of rotation 15 which is at a distance from an optical axis 14 of the light module 5, 6 and extending transversely thereto. In this way, the diaphragm 12 can be moved out of or out of the beam path, and the light distribution emitted by the light module 5, 6 can be switched between a dimmed light distribution (for example low beam) and a non-dimmed light distribution (for example high beam).

The light source used in the light module 5, 6 7 is in detail in FIG. 3 shown. The light source 7 comprises a gas discharge lamp and a control module 16 with a driver circuit for generating an intermediate voltage or an operating voltage for the gas discharge lamp, an ignition module 17 for generating a high voltage (ignition voltage) from the intermediate voltage and a gas-filled burner 18. The burner 18 is preferably with filled with a noble gas or gas mixture. In the burner 18 protrude two electrodes 19, 20, between which an arc is ignited for the operation of the light source 7 and maintained for the duration of the operation of the light source 7. The gas-filled burner 18 (so-called inner glass bulb) is in turn arranged inside a preferably air-filled glass bulb 24 (so-called outer glass bulb). Both the burner 18 and the glass bulb 24 are preferably made of a quartz glass. Feed lines 25, 26, via which the ignition voltage or the operating voltage is applied to the electrodes 19, 20, extend through the glass bulb 24. The lines 25, 26 are guided through the base 9 in the interior of the housing 21 and there connected to the control module 16 and / or the ignition module 17.

In the light source 7 according to the invention, the control module 16, the ignition module 17 and the burner 18 are attached to a common carrier system 21 and combined into one unit. The support system 21, in addition to the attachment of the sub-components 16, 17 and the functions of a housing for the electrical circuits of the control module 16 and the ignition module 17 and the function of a heat sink, on the waste heat of the electronic components of the control module 16 and / or the ignition module 17th is delivered to the environment. The housing 21 protects the circuits or electronic components of the control module 16 and the ignition module 17 from dirt, moisture and mechanical damage. In addition, the housing 21 provides an EMC shield so that electromagnetic interference from outside does not affect the circuits or electronic components of the control module 16 and the ignition module 17 and on the other hand, electromagnetic interference of the circuits or electronic components of the control module 16 and the ignition module 17 not on outside circuits and components act.

The electronic components of the circuits of the control module 16 and the ignition module 17 are arranged on one or more printed circuit boards 22, mechanically fixed and electrically contacted. About formed on the circuit board 22 traces, the two modules 16, 17 with each other and with other components for power supply and / or signal transmission in electrical connection. The other components are, for example, a plug or socket element 23, which is formed on the underside of the printed circuit board 22 and protrudes through an opening in the housing 21 to the outside. To the plug or socket member 23, a corresponding socket or plug element (in FIG. 3 not shown) are connected to a connecting line, via which the light source 7 and the control module 16 and the ignition module 17 with a higher-level control unit, for example, a so-called body controller, as well as for power to a power supply, such as a motor vehicle battery, in communication.

In the case of the light source 7 according to the invention, it is possible for the first time to place the control module 16 in the immediate vicinity of the light source To position burner 18 without causing thermal problems or overheating of the electronic components of the control module 16. This is made possible by the fact that the burner 18 has a reduced lamp power compared to conventional gas discharge lamps. The high packing density of the light source 7 according to the invention is possible because the reduced power of the light source 7 makes thermal management manageable from an economic point of view. The various subcomponents of the light source 7 according to the invention, namely the control module 16, the ignition module 17 and the burner 18, can be manufactured and tested as separate modules. In the final manufacturing process then all required modules are mounted in the common carrier system 21. From a thermal point of view, it is advantageous to mount modules which can withstand high temperatures, for example the ignition module 17, in the top of the carrier system 21. Modules that are not as highly stressed thermally, such as the control module 16 or the male / female member 23 are mounted below in the carrier system 21. The light source 7 according to the invention allows a particularly compact construction of a gas discharge lamp. Due to the small size, it is recommended for cooling to increase the proportion of radiated heat energy by appropriate measures. For this purpose, it is possible to carry out the surface of the housing 21 with a particularly high emissivity (for example 0.9). The particularly high emissivity can be achieved, for example, by painting the housing 21 with suitable paints. The paints must behave in the infrared range ideally like a "black spotlight".

Claims (8)

1. a light source (7) with a gas discharge lamp, including

   - a control module (16) with a driver circuit;

   - an ignition module (17) for producing a high voltage; and

   - a gas-filled burner (18), in which an electric arc is ignited and maintained between two electrodes (19, 20),

   wherein the control module (16), the ignition module (17) and the burner (18) are attached to a mutual support system (21) and combined into a unit,
   characterized in that the light source (7) has a lamp base (9), which is embodied such that via the lamp base (9), the light source (7) can be bayonet-mounted in a receptacle opening embodied on a back side of a reflector (8).
2. The light source (7) as set forth in claim 1, wherein the support system includes a housing, in particular a metal housing.
3. The light source (7) as set forth in claim 2, wherein the housing has means for increasing emission of heat to the surrounding area.
4. The light source (7) as set forth in claim 2 or 3, wherein the surface of the housing has an emission ratio of greater than 0.7, in particular greater than 0.9.
5. The light source (7) as set forth in one of claims 1-4, wherein the surface of the housing is painted.
6. The light source (7) as set forth in one of claims 1-5, wherein in an operating position of the light source, the ignition module is arranged above the control module and/or the burner in the support system.
7. Lighting equipment (1) for a motor vehicle, including at least one light source (7) as set forth in one of claims 1-6.
8. Lighting equipment (1) as set forth in claim 7, wherein the lighting equipment (1) is embodied as a motor-vehicle headlight.

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