EP3382268B1 - Vehicle headlight and cooling system - Google Patents

Description

The invention relates to a vehicle headlight, comprising a headlight housing, at least one light source, at least one projection lens, at least one cooling channel and a cooling medium, the at least one light source being set up to emit light in the form of a light beam in the direction of the at least one projection lens and in front of the vehicle to form a light image on the road, and the at least one light source and the at least one projection optics are located within the headlight housing, and the at least one cooling channel is thermally conductively connected to at least one heat source located within the headlight housing, and the at least one cooling channel is set up to cool the at least one heat source when the cooling medium flows through it.

The invention also relates to a cooling system which comprises at least one cooling generator, a cooling medium and at least one cooling line.

From the EP 2 644 989 A1 and US 2005/236144 A1 headlight assemblies are known.

In the development of the current headlight systems, the focus is more and more on the desire to be able to project a high-resolution, homogeneous light image onto the roadway. The term “roadway” is used here for a simplified representation, because of course it depends on the local conditions whether a photograph is actually located on the roadway or whether it extends beyond it. In principle, the light image in the sense used corresponds to a projection onto a vertical surface in accordance with the relevant standards that relate to vehicle lighting technology.

In order to meet this need, headlights, among other things, have been developed in which a variably controllable reflector surface is made up of a plurality of micromirrors is formed and a light emission, which is generated by a light module, is reflected in the emission direction of the headlight. Such lighting devices are advantageous in vehicle construction because of their very flexible light functions, since the illuminance can be individually regulated for different light areas and any light functions can be implemented with different light distributions, such as a low beam light distribution, a cornering light distribution, a City light distribution, motorway light distribution, cornering light distribution, high beam light distribution or the imaging of glare-free high beam.

The so-called Digital Light Processing (DLP®) projection technology is used for the micromirror arrangement, in which images are generated by modulating a digital image onto a light beam. A rectangular arrangement of movable micromirrors, also known as pixels, divides the light beam into partial areas and then reflects it pixel by pixel either into the projection path or out of the projection path.

The basis for this technology is an electronic component that contains the rectangular arrangement in the form of a matrix of mirrors and their control technology and is called a "Digital Micromirror Device" (DMD).

A DMD microsystem is a surface light modulator (Spatial Light Modulator, SLM), which consists of micromirror actuators arranged in a matrix, that is, tiltable reflective surfaces, for example with an edge length of about 16 µm. The mirror surfaces are designed in such a way that they can be moved by the action of electrostatic fields. Each micromirror is individually adjustable in angle and usually has two stable end states, between which you can switch up to 5000 times within a second. The individual micromirrors can, for example, each be controlled by pulse width modulation (PWM) in order to map further states of the micromirrors in the main beam direction of the DMD arrangement, whose reflectivity averaged over time lies between the two stable states of the DMD. The number of mirrors corresponds to the resolution of the projected image, whereby a mirror can represent one or more pixels. DMD chips with high resolutions in the megapixel range are now available. The technology on which the adjustable individual mirrors are based is Micro-Electro-Mechanical-Systems (MEMS) technology.

While DMD technology has two stable mirror states and the reflection factor can be set by modulating between the two stable states, "Analog Micromirror Device" (AMD) technology has the property that the individual mirrors can be set in variable mirror positions, which are each in a stable state there.

However, DMD components are particularly sensitive to temperature fluctuations, which on the one hand can be expressed in an uneven reflection behavior of the individual mirrors, and on the other hand can lead to a shortened service life. Consequently, appropriate cooling of the DMD component is an important aspect in the development of headlights. This can be done by suitable cooling of the DMD component, as well as by a corresponding dissipation of heat, which is generated, for example, by the light source. Complex and precise cooling of a vehicle headlight often results in a large installation space required by the headlight and in correspondingly high production costs. Both of these do not meet the commercial requirements for an effective headlight.

It is an object of the invention to overcome the stated disadvantages of the prior art and to provide a vehicle headlight with efficient cooling and also an efficient cooling system which meets the stated requirements.

The object is achieved by a vehicle headlight of the type mentioned at the outset, the at least one cooling duct comprising at least one releasable connecting coupling which is inserted into the cooling duct. It can thereby be achieved that the vehicle headlight can have a cooling device, with the generation of a cold cooling medium not taking place within the headlight, but rather by an external unit. As a result, the vehicle headlamp can be made smaller and less expensive. In addition, a cold cooling medium can be generated more effectively and more cost-effectively. This is particularly advantageous because at least two vehicle headlights can use the same unit to generate a cold cooling medium. It is also possible to include other components to be cooled in a vehicle cooling system. The releasable connection coupling, for example a clampable or screwable flange connection, enables a vehicle headlight to be easily installed and removed from a motor vehicle.

This object of the invention is also achieved by a cooling system of the type mentioned at the outset, which additionally has at least one vehicle headlight according to the invention and at least one further unit to be cooled, in particular another vehicle headlight according to the invention or an accumulator unit of an electric vehicle, which has at least one accumulator cell and at least an accumulator cooling arrangement includes, is coupled to the cooling system, and can be flowed through by the cooling medium. It can thereby be achieved that an existing, efficient vehicle cooling system is additionally used to cool one or more vehicle headlights.

It is clear that the more individual headlights are integrated in a vehicle, the greater the advantage. In other words, it is advantageous if, for example, several headlights or several pairs of headlights are used in separate headlight housings, for example for different light functions, and these several headlights use a common cooling system.

According to the invention, the cold cooling medium is generated outside the headlight housing. Furthermore, the vehicle headlight further comprises a micromirror arrangement, wherein the micromirror arrangement is inserted between the at least one light source and the at least one projection optics in the beam path of the light beam, and the micromirror arrangement is set up to reflect light emitted by the light source in the direction of the at least one projection optics, wherein the micromirror assembly is located within the headlamp housing and the at least one heat source comprises the micromirror assembly.

In particular, micromirror arrangements in the form of optoelectronic components require particularly reliable and precise temperature control in order not, for example, to adversely affect the service life of the component. The vehicle headlight is therefore particularly well suited to provide such cooling.

This also applies if the at least one heat source comprises the at least one light source, the light source being designed as an LED, OLED or laser diode. A heat source in the form of an optical absorber is particularly well suited for this purpose, since these components generate a high level of heat loss. With such a vehicle headlight it can consequently be achieved that the waste heat to the outside of the Headlight can be transported and therefore the headlight can be made even smaller and cheaper. Thus, for example, several headlights can use the same unit to generate a cold cooling medium or use the same cooling medium.

In a favorable embodiment of the invention, the vehicle headlight further comprises a condenser for condensing water vapor, which is located inside the headlight housing and is connected to the cooling duct in a thermally conductive manner. It can thereby be achieved that a transparent front window of the vehicle headlight does not have to be specially coated in order to prevent fogging of the window, which would adversely affect the optical function of the headlight. As a result, the air inside the headlight housing is dehumidified.

A capacitor can be a separate assembly, for example a separate heat sink, or a functional unit formed jointly with other headlight components, for example together with a heat sink of an electronic component of the headlight. A capacitor is a device whose surface temperature is lower than the surface temperatures of neighboring components or component areas. The condenser can be formed in that the condenser is arranged in the cooling channel in the flow direction of the cooling medium as close as possible after the releasable connection coupling, and therefore has a lower temperature than the components to be cooled, which are arranged downstream in the cooling channel and already waste heat to the cooling medium have given up.

The condenser is at least partially located within the headlight housing and preferably on the cooling channel upstream of the light source.

The condensate that forms on the condenser can preferably drain through a drain opening.

In one embodiment, the cooling medium is gaseous and preferably air, with at least part of the cooling medium inside the vehicle headlight being taken from the cooling channel by means of a branch and being fed to the interior of the headlight housing in order to produce a Generate atmospheric overpressure compared to the pressure outside the vehicle headlights. The condensate that forms on the condenser and flows to a pressure compensation valve or a drain opening can thus be drained out of the headlight housing. With this embodiment, the efficiency of the dehumidification within the headlight housing can be improved.

In order to further improve the efficiency of the entire cooling system, the vehicle headlight can additionally comprise at least one throttle valve which is mounted inside the headlight housing or on the headlight housing. As a result, the assembly of the throttle valve can be facilitated by integrating it in one piece into the vehicle headlight.

In a further development of the invention, the cooling system further comprises an electrical control device and at least one throttle valve, the at least one throttle valve and the at least one cooling channel being inserted into the cooling line. This enables efficient regulation of the cooling system to be achieved.

The at least one throttle valve is arranged upstream of the at least one cooling duct and the vehicle headlight further comprises at least one first temperature sensor, which is electrically connected to the electrical control device via at least one sensor line. The electrical control device is also set up to regulate the flow of the cooling medium through the vehicle headlight by means of the at least one throttle valve via at least one control line.

It can thereby be achieved that the flow into the headlight is regulated and the other components in the cooling system, for example the accumulator unit, can be cooled better.

The accumulator unit preferably comprises at least one second temperature sensor which is electrically connected to the electrical control device via at least one sensor line. The electrical control device is also set up to regulate the flow of the cooling medium through the accumulator unit by means of the at least one throttle valve via at least one control line. As a result, efficient control of the entire cooling system can be achieved.

In other words, the cooling system can include at least one cooling generator, a cooling medium, at least one cooling line, at least one vehicle headlight and at least one further unit to be cooled, the at least one vehicle headlight and the at least one unit to be cooled being coupled to the cooling system and through which the cooling medium can flow is.

The at least one vehicle headlight can include a headlight housing, at least one light source, at least one projection lens, at least one cooling channel and a cooling medium.

The at least one light source is set up to emit light in the form of a light beam in the direction of the at least one projection optics and to form a light image on the road in front of the vehicle. The at least one light source and the at least one projection optics are located within the headlight housing. The at least one cooling channel is thermally conductively connected to at least one heat source that is located inside the headlight housing. The at least one cooling channel is designed to cool the at least one heat source when the cooling medium flows through it.

The at least one cooling channel comprises at least one releasable connecting coupling which is inserted into the cooling channel.

The cooling system further comprises an electrical control device and at least one throttle valve, wherein the at least one throttle valve and the at least one cooling channel are inserted into the cooling line, wherein the at least one throttle valve is arranged upstream of the at least one cooling channel.

The vehicle headlight further comprises at least one first temperature sensor, which is electrically connected to the electrical control device via at least one sensor line. The electrical control device is set up to regulate the flow of the cooling medium through the vehicle headlight by means of the at least one throttle valve via at least one control line.

In addition, the at least one further unit to be cooled can be a further vehicle headlight, which is coupled to the cooling system and through which the cooling medium can flow.

Furthermore, the at least one further unit to be cooled can comprise an accumulator unit of an electric vehicle, which contains at least one accumulator cell and at least one accumulator cooling arrangement, which is coupled to the cooling system and through which the cooling medium can flow.

The accumulator unit can include at least one second temperature sensor, which is electrically connected to the electrical control device via at least one sensor line. The electrical control device is set up to regulate the flow of the cooling medium through the accumulator unit by means of the at least one throttle valve via at least one control line.

In a further development of the invention, the cooling medium is a fluid, preferably cooling water or oil. The at least one cooling line forms a closed cooling circuit with the at least one cooling generator.

The cooling generator can contain, for example, a compressor, preferably the compressor of an air conditioning system, which generates cold and sets the cooled cooling medium in a flow movement in the cooling line by means of a fan for a gaseous cooling medium or a pump for a fluid cooling medium. It can thereby be achieved that particularly high amounts of heat are dissipated from the headlight and the headlight can be made particularly small. In addition, cost advantages can arise. A cooling generator often includes an evaporator, an expansion valve, a compressor, a condenser of the cooling generator, a filter or dryer and a condenser fan.

In this context, it is clear that a cooling generator can also be used to generate warm air in order, for example, to heat the connected components in winter when outside temperatures are low. This can be done, for example, by heating coils which are arranged in the cooling line and operated electrically.

Fig. 1

ein Blockschaltbild einer ersten Ausführungsform eines erfindungsgemäßen Kühlsystems mit einem erfindungsgemäßen Fahrzeugscheinwerfer mit einem fluiden Kühlmedium,

Fig. 2

ein Blockschaltbild einer zweiten Ausführungsform eines erfindungsgemäßen Kühlsystems mit einem erfindungsgemäßen Fahrzeugscheinwerfer mit einem gasförmigen Kühlmedium, und

Fig. 3

ein Blockschaltbild einer dritten Ausführungsform eines erfindungsgemäßen Kühlsystems mit einem erfindungsgemäßen Fahrzeugscheinwerfer mit einem gasförmigen Kühlmedium.

The invention and its advantages are described in more detail below on the basis of non-limiting exemplary embodiments which are illustrated in the accompanying drawings. The drawings show in

Fig. 1

a block diagram of a first embodiment of a cooling system according to the invention with a vehicle headlight according to the invention with a fluid cooling medium,

Fig. 2

a block diagram of a second embodiment of a cooling system according to the invention with a vehicle headlight according to the invention with a gaseous cooling medium, and

Fig. 3

a block diagram of a third embodiment of a cooling system according to the invention with a vehicle headlight according to the invention with a gaseous cooling medium.

With reference to Figs. 1 to 3 Embodiments of the invention will now be explained in more detail with reference to schematic representations, the arrangement shown not corresponding to the actual geometry. In particular, parts that are important for the invention are shown in a headlight, it being clear that a headlight also contains many other parts, not shown, which enable useful use in a motor vehicle, such as, in particular, a car or motorcycle. For the sake of clarity, components, control electronics, further optical elements, mechanical adjustment devices or holders are therefore not shown.

Fig. 1 shows a schematic representation of a vehicle headlight 100 according to the invention, which comprises a headlight housing 101, at least one light source 102, at least one primary optics 103, at least one projection optics 104, a cooling channel 107 and a cooling medium. A cooling system 10 according to the invention is also shown.

Further embodiments of the invention are possible in which a plurality of cooling channels run through a vehicle headlight, which are supplied with a cooling medium, for example via distributors, from a common cooling generator.

The cooling system 10 comprises at least one cooling generator 11, a cooling medium and at least one cooling line 12. In addition, there are at least two units to be cooled which are supplied together with a cooling medium by the cooling system 10. The at least two units to be cooled can be at least one vehicle headlight according to the invention, or also a battery unit 30 of an electric vehicle, which comprises at least one battery cell 32 and at least one battery cooling arrangement. Accordingly, it is clear that two or more headlights 100 according to the invention can be included in multi-lane vehicles.

Vehicle headlights according to the invention can in design variants such as a high beam or low beam function, but also include other light functions such as intelligent projectors that dynamically project traffic information or navigation information onto the roadway.

The at least one light source 102 is set up to emit light in the form of a light beam 105 in the direction of the at least one projection optics 104 and to form a light image on the road in front of the vehicle. The projection optics 104 are oriented in the direction of travel of the vehicle.

The cooling channel 107 is connected in a thermally conductive manner to at least one heat source, for example an electrical consumer or a heat sink, which is located within the headlight housing 101. The cooling channel 107 is set up to cool the at least one heat source when the cooling medium flows through it.

The cooling channel 107 furthermore comprises at least one releasable connecting coupling 108, 109 which is inserted into the cooling channel 107. In this exemplary embodiment, two releasable connecting couplings 108, 109 are shown.

The vehicle headlight 100 further comprises a micromirror arrangement 110, the micromirror arrangement 110 being inserted between the at least one light source 102 and the at least one projection optics 104 in the beam path of the light beam 105. The micromirror arrangement 110 is set up to reflect light emitted by the light source 102 in the direction of the at least one projection optics 104.

Depending on the control of the micromirror arrangement 110, which is usually done by an electronic circuit (not shown), individual micromirrors of the micromirror arrangement 110 can be controlled in such a way that light is reflected in the direction of the at least one first projection direction or, alternatively, is reflected in another, second projection direction , in which an optical absorber 111 is located, which converts the energy of the incident light into heat. The beam path 105 in the first projection direction is in FIG Fig. 1 shown with a solid arrow and the beam path 105, which is located in the second projection direction, which can emerge from the headlight 100 through the transparent front pane 119, is shown with a dashed arrow.

The micromirror arrangement 110 is located within the headlight housing 101 and the at least one heat source comprises the micromirror arrangement 110.

In this example, the at least one heat source comprises in the form of an electrical power component the at least one light source 102, which can in particular be an LED, an OLED or a laser diode, and an optical absorber 111 Heat sinks 112, 113, 114 include.

In an advantageous development of the invention, the vehicle headlight 100 further comprises a condenser 115 for condensing water vapor. The capacitor 115 is located inside the headlight housing 101 and is connected to the cooling duct 107 in a thermally conductive manner. It can thereby be achieved that the water content of the air, which is enclosed in the headlight housing 101, does not condense on the transparent windshield 119 and thus impair the optical function of the headlight, but condenses on the condenser 115, since this has a lower temperature than the Temperature of the transparent windshield 119 of the headlight, which in turn is essentially determined by the outside temperature outside the vehicle. This process is also known as condensation or resublimation. This arrangement makes it possible to dispense with an expensive special coating of the optically transparent front pane 119 of the headlight 100, since the condensation can largely take place on the condenser 115 and not on the optically transparent front pane 119 of the headlight housing 101 or on others Components of the headlight 100 that contribute to its optical function, such as the light source 102, the primary optics 103, the projection optics 104 or the micromirror arrangement 110.

In a further development of the invention, a gas, for example air, can be used as the cooling medium that already has a very low moisture content. This can be achieved by using conditioned air, which was generated, for example, by a cooling compressor as a cooling generator. It can thereby be achieved that the condensation or condensation of moisture within the vehicle headlight is reduced overall, since as a result less moisture is present overall within the vehicle headlight.

The capacitor 115 is preferably located at least partially within the headlight housing 101 and preferably on the cooling channel 107 upstream of the light source 102.

As a result, it can be achieved that the cooling medium is conducted to the condenser 115 immediately after it has entered the cooling channel 107, i.e. the point with the lowest temperature of the cooling medium within the headlight 100, and the condenser 115 has a particularly low temperature within the headlight 100, whereby the condenser 115 is particularly efficient and the water vapor can largely condense or resublimate on the condenser 115. The transition between the gaseous and liquid state of water as a function of pressure and temperature can be seen from the so-called phase diagram, as is known to the person skilled in the art.

A corresponding embodiment of the vehicle headlight 100 can ensure that the condensate that forms on the condenser 115 can preferably run off through a drain opening 116. For example, the drain opening 116 can be funnel-shaped and in the installed position it can be located below the condenser 115, as a result of which the condensate can drip off and run off. The cooling channel 107 can be partially surrounded by thermal insulation in order to absorb the generated cold of the cooling medium in the cooling channel 107 in a largely targeted manner, the heat of the heat source or to transfer the cold to the condenser 115.

It is advantageous if the vehicle headlight 100 additionally comprises at least one throttle valve 13 which is mounted within the headlight housing 101 or on the headlight housing 101. The flow of the cooling medium through the cooling channel 107 can be regulated by such a throttle valve. If the throttle valve 13 is installed in one piece with the headlight housing 101, the installation of both components is facilitated and additional fastening parts can be saved.

In the Fig. 1 a cooling system 10 is also shown, which comprises at least one cooling generator 11, a cooling medium and at least one cooling line 12 and a flow of the cooling medium in a flow direction 15 to supply the heat sources in the headlight 100, such as the light source 102, the micromirror arrangement 110, the optical Absorber 111 or the heat sinks 112, 113, 114 and the components to be cooled, such as the capacitor 115, but also in the accumulator unit 30, the accumulator cells 32 are generated.

In addition, an accumulator unit 30 of an electric vehicle, which contains a plurality of accumulator cells 32 and at least one accumulator cooling arrangement, is shown, which is also coupled to the cooling system 10 and through which the cooling medium can flow.

Through the joint generation of a cooled cooling medium by the cooling generator 11 for the vehicle headlight 100 and the accumulator unit 30, significant synergy effects can be used, as a result of which overall less installation space and cost-effective production can be achieved.

The cooling system 10 further comprises an electrical control device 20 and at least one throttle valve 13, the at least one throttle valve 13 and the at least one cooling channel 107 being inserted into the cooling line 12.

The electrical control device 20 can be designed as a separate assembly, or it can only be a function of a complex control device which, for example, performs other control functions of the vehicle.

The at least one throttle valve 13 is arranged upstream of the at least one cooling channel 107 in order to regulate the inflow into the headlight 100 or the flow rate through the headlight 100.

The vehicle headlight 100 further comprises a first temperature sensor 106, which is electrically connected to the electrical control device 20 via at least one sensor line 21. As a result, the temperature of the vehicle headlight 100 can be determined and the cooling output can be adjusted accordingly. The electrical control device 20 is set up to regulate the flow of the cooling medium through the vehicle headlight 100 by means of the at least one throttle valve 13 via at least one control line 23, 24. It is clear that the at least one sensor line 21 can be formed, for example, by a vehicle bus, such as a CAN or LIN bus.

In this exemplary embodiment, the accumulator unit 30 comprises at least one second temperature sensor 31, which is electrically connected to the electrical control device 20 via at least one sensor line 22. As a result, the temperature of the accumulator unit 30 can be determined and the cooling output can be adjusted accordingly. It is clear that each accumulator cell can have its own temperature sensor. It is also clear to the person skilled in the art that the at least one sensor line 22 can be formed, for example, by a vehicle bus, such as a CAN or LIN bus. The same applies to the at least one control line 23, 24, 25.

The electrical control device 20 is set up to regulate the flow of the cooling medium through the accumulator unit 30 by means of the at least one throttle valve 14 via at least one control line 23, 25.

Through the shared use of the electrical control device 20 for the cooling generator 11 by the vehicle headlight 100 and the accumulator unit 30, further synergy effects can be used, whereby a smaller installation space and a cost-effective production can be achieved.

It is favorable if the cooling medium is a fluid, preferably cooling water or oil, and the at least one cooling line 12 forms a closed cooling circuit with the at least one cooling generator 11.

The cooling generator 11 can, for example, comprise one or more heat exchangers (not shown) through which the wind of the moving vehicle flows and is thereby cooled. In addition, the cooling generator 11 can contain a pump (not shown) in order to generate a flow in the flow direction 15 in the cooling line 12.

Fig. 2 shows a further embodiment of a vehicle headlight 200 according to the invention, in which the cooling medium is gaseous and preferably air.

At least part of the gaseous cooling medium can be removed from the cooling channel 207 within the vehicle headlight 200 by means of a branch 217 and fed to the interior of the headlight housing 201. A nozzle (not shown) can be attached to the junction 217, which guides the exiting flow of the cooling medium to a certain point, for example in the area of the condenser 215. It is clear that the cooling generator must be set up to suck in air and the To supply the cooling line in order to supply the volume of the air flowing out in the headlight 201 to the cooling system 10 again. The junction 217 can also be set up to generate an air flow in the headlight housing 201 so that resublimation on the components 202, 203, 204 or 210 of the headlight 200 that are important for the optical function is reduced, for example by removing waste heat (not shown) by a Heat sink 214 is discharged, flows in the direction of the projection lens 204 or the transparent front panel 219. As a result, an atmospheric overpressure can be generated inside a headlight housing 201 compared to the pressure outside the vehicle headlight 200.

The transition between the gaseous and liquid state of water as a function of pressure and temperature can be seen from the so-called phase diagram, as is known to the person skilled in the art. A higher pressure allows resublimation or condensation at a lower temperature. Thus, by a headlight, the one Has atmospheric overpressure, an easier or more efficient dehumidification of the air within the headlight can be achieved.

The condensate that forms on the condenser 215 can flow, for example, through a funnel-shaped shape to a pressure compensation valve 218 and the condensate can be diverted out of the headlight housing 201 through the pressure compensation valve 218. It is favorable if the headlight housing 201 is designed predominantly tight and the pressure equalization takes place predominantly through the pressure equalization valve 218, which also ensures that no moisture can get into the headlight housing 201 from the outside. The pressure equalization valve 218 can alternatively also be designed as a gas-permeable membrane.

For example, the pressure compensation valve 218 can be located in the installed position below the condenser 215, whereby the condensate can drip off and run off easily. It can thereby be achieved that the drainage of the condensate is facilitated and the dehumidification of the air inside the vehicle headlight is improved.

Otherwise, the statements of Fig. 1 , wherein the reference symbols of the components of the headlight 200 correspond to the numbers of the reference symbols of the headlight 100 increased by the number 100.

Fig. 3 shows a further embodiment of a vehicle headlight 300 according to the invention, in which the cooling medium is gaseous and preferably air.

At least part of the gaseous cooling medium can be removed from the cooling duct 307 within the vehicle headlight 300, in that the cooling duct 307 has an open end which is located in the interior of the headlight housing 301. A nozzle (not shown) can be attached to the open end of the cooling channel 307, which nozzle guides the exiting flow of the cooling medium to a certain point, for example in the area of the condenser 315. It is clear that the cooling generator must be set up to supply air to be sucked in and fed to the cooling line in order to feed the volume of the air flowing out in the headlight 301 to the cooling system 10 again. The open end of the cooling channel 307 can also be set up to generate an air flow in the headlight housing 301 that resublimation to the for the components 302, 303, 304 or 310 of the headlight 300 that are important for the optical function are reduced, for example by waste heat (not shown), which is given off by a heat sink 314, flowing in the direction of the projection lens 304 or the transparent front pane 319. As a result, an atmospheric overpressure can be generated inside a headlight housing 301 compared to the pressure outside the vehicle headlight 300.

The condensate that forms on the condenser 315 can, for example, flow through a funnel-shaped shape to a pressure compensation valve 318 and the condensate can be diverted out of the headlight housing 301 through the pressure compensation valve 318. It is favorable if the headlamp housing 301 is designed to be predominantly tight and the pressure equalization takes place predominantly through the pressure equalization valve 318, which also ensures that no moisture can get into the headlamp housing 301 from the outside. The pressure equalization valve 318 can alternatively also be designed as a gas-permeable membrane. In the simplest case, the pressure compensation valve 318 is replaced by a simple opening which can also serve as a drain opening and through which the condensate can drain when the headlight is in the installed position.

For example, the pressure equalization valve 318 can be located in the installed position below the condenser 315, as a result of which the condensate can drip off and run off easily. It can thereby be achieved that the drainage of the condensate is facilitated and the dehumidification of the air inside the vehicle headlight is improved.

In this context, it is assumed that the open end of the cooling channel 307 can flow towards a point in the headlight 300, this point being referred to as a capacitor 315. This arrangement, in which the cooling medium flows from the cooling channel 307, preferably in a directed manner towards the condenser 315, is functionally equivalent to a thermally conductive connection between the condenser 315 and the cooling channel 307.

Otherwise, the statements of Fig. 1 and 2 , wherein the reference symbols of the components of the headlight 300 correspond to the numbers of the reference symbols of the headlight 100 increased by the number 200.

In this embodiment, too, the gaseous cooling medium entering the vehicle headlight can flow towards a special location through which a condenser can be formed in order to force the resublimation of the air in the headlight on the condenser. A favorable arrangement, for example of several heat sources, preferably vertically to one another in the installation position of the headlight, can support the function. Resublimation occurring on the components of the headlamp that is important for the optical function can thereby be reduced. There is no need for an expensive anti-fog coating on the transparent front panel of the headlight.

In connection with the embodiments shown, it is clear that the features of the claims can be combined with one another. For example, it is possible to provide the shown headlights 100, 200 or 300 with drain openings or valves or membranes, depending on the respective requirements in the application of a headlight. It is also possible for different components within the headlight to be cooled, even if they do not explicitly use a heat sink, but rather are arranged, for example, on a circuit board that is thermally coupled to the cooling channel by suitable coupling.

List of reference symbols:

10

Cooling system

11

Cooling generator

12th

Cooling pipe

13.14

Throttle valve

15th

Flow direction

20th

electrical control device

21, 22

Sensor cable

23, 24, 25

Control line

30th

Accumulator unit

31

second temperature sensor

32

Accumulator cell

100, 200, 300

Vehicle headlights

101, 201, 301

Headlight housing

102, 202, 302

Light source

103, 203, 303

Primary optics

104, 204, 304

Projection optics

105, 205, 305

Beam of light

106, 206, 306

first temperature sensor

107, 207, 307

Cooling duct

108, 109, 208, 209, 309

Connecting coupling

110, 210, 310

Micromirror array

111, 211, 311

optical absorber

112, 113, 114, 212, 213, 214, 312, 313, 314

Heat sink

115, 215, 315

capacitor

116

Drain opening

217

Junction

218, 318

Pressure equalization valve

119, 219, 319

Windshield

Claims (8)

1. Vehicle headlamp (100, 200, 300), comprising a headlamp housing (101, 201, 301), at least one light source (102, 202, 302), at least one projection optic (104, 204, 304), at least one cooling channel (107, 207, 307) and a cooling medium, wherein the at least one light source (102,202,302) is arranged to emit light in the form of a light beam (105,205,305) in the direction of the at least one projection optics (104, 204, 304) and to form a light image on the road in front of the vehicle and the at least one light source (102, 202, 302) and the at least one projection optics (104, 204, 304) are located inside the headlamp housing (101, 201, 301), and the at least one cooling channel (107, 207, 307) is thermally conductively connected to at least one heat source which is located inside the headlamp housing (101, 201, 301), and the at least one cooling channel (107, 207, 307) is set up to cool the at least one heat source when the cooling medium flows through it, wherein, the at least one cooling channel (107, 207, 307) comprises at least one detachable connecting coupling (108, 109, 208, 209, 309) which is inserted into the cooling channel (107, 207, 307), characterized in that the generation of the cold cooling medium takes place outside the headlamp housing (101, 201, 301), and in that the vehicle headlight (100, 200, 300) further comprises a micromirror arrangement (110, 210, 310), the micromirror arrangement (110, 210, 310) being inserted between the at least one light source (102, 202, 302) and the at least one projection optics (104, 204, 304) in the beam path of the light beam (105, 205, 305), and the micromirror arrangement (110, 210, 310) is arranged to convert light emitted by the light source (102, 202, 302) in the direction of the at least one projection optics (104, 204, 304), wherein the micromirror arrangement (110, 210, 310) is located within the headlamp housing (101, 201, 301) and the at least one heat source comprises the micromirror arrangement (110, 210, 310).
2. Vehicle headlamp (100, 200, 300) according to claim 1, characterized in that the at least one heat source comprises the at least one light source (102, 202, 302), in particular an LED, an OLED or a laser diode, or an optical absorber (111, 211, 311).
3. Vehicle headlamp (100, 200, 300) according to claim 1 or 2, characterized in that the vehicle headlamp (100, 200, 300) further comprises a capacitor (115, 215, 315) for condensing water vapor, which is located inside the headlamp housing (101, 201, 301) and is thermally conductively connected to the cooling channel (107, 207, 307), wherein the condenser (115, 215, 315) is located at least partially within the headlamp housing (101, 201, 301) and is preferably located at the cooling channel (107, 207, 307) upstream of the light source (102, 202, 302), and the condensate formed at the condenser (115, 215, 315) can preferably drain off through a drain opening (116).
4. Vehicle headlamp (200) according to claim 3, characterized in that the cooling medium is gaseous, preferably air, wherein at least a part of the cooling medium within the vehicle headlamp (200) is taken from the cooling channel (207) by means of a branch (217) and is supplied to the interior of the headlamp housing (201), to create an atmospheric overpressure inside the headlamp housing (201) with respect to the pressure outside the vehicle headlamp (200), and the condensate which forms at the condenser (215) and flows toward a pressure equalization valve (218) or a drain opening through which the condensate can be drained out of the headlamp housing (201).
5. Vehicle headlamp (100, 200, 300) according to any one of claims 1 to 4, characterized in that the vehicle headlamp (100, 200, 300) additionally comprises at least one throttle valve (13) mounted inside the headlamp housing (101, 201, 301) or on the headlamp housing (101, 201, 301).
6. Cooling system (10) comprising at least one cooling generator (11), a cooling medium and at least one cooling line (12), characterized in that additionally at least one vehicle headlamp (100, 200, 300) according to one of claims 1 to 5 and at least one further unit to be cooled, in particular a further vehicle headlamp (100, 200, 300) according to one of claims 1 to 5 or an accumulator unit (30) of an electric vehicle, which includes at least one accumulator cell (32) and at least one accumulator cooling arrangement, is included and can be coupled to the cooling system (10) and have the cooling medium flowing through it.
7. Cooling system (10) according to claim 6, characterized in that the cooling system (10) further comprises an electrical control device (20) and at least one throttle valve (13), wherein the at least one throttle valve (13) and the at least one cooling channel (107, 207, 307) are inserted into the cooling line (12), wherein the at least one throttle valve (13) is arranged upstream of the at least one cooling channel (107, 207, 307), and the vehicle headlamp (100, 200, 300) further comprises at least one first temperature sensor (106, 206, 306) which is electrically connected to the electrical control device (20) via at least one sensor line (21) and the electrical control device (20) is set up to regulate the flow of the cooling medium through the vehicle headlight (100, 200, 300) by means of the at least one throttle valve (13) via at least one control line (23, 24), and preferably the accumulator unit (30) comprises at least one second temperature sensor (31) which is electrically connected to the electrical control device (20) via at least one sensor line (22), and the electrical control device (20) is arranged to regulate the flow of the cooling medium through the accumulator unit (30) by means of the at least one throttle valve (14) via at least one control line (23, 25).
8. Cooling system (10) according to one of claims 6 or 7, characterized in that the cooling medium is a fluid, preferably cooling water or oil, and the at least one cooling line (12) forms a closed cooling circuit with the at least one cooling generator (11).

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