Headlamp for vehicle and dewell avoidance method

Abstract

The invention relates to a headlight for a vehicle, comprising a housing (2) in which a light source unit (9) is arranged, which has a plurality of light sources (7, 14) and an optical unit (10) for generating a predetermined light distribution, and comprising a cover lens (5) which closes a light exit opening of the housing (2), the invention relates to a headlight (1) for a motor vehicle, comprising a control unit (18) for controlling a light source (7, 14) and comprising an anti-condensation means for preventing condensation on the surface of an optical unit (10) and / or of a cover lens (5), characterized in that the control unit (18) comprises a control program (19) for controlling the light source (7, 14). The light source unit (6) is operated at an anti-condensation power that is increased in comparison to a normal power provided for generating a predetermined light distribution, the power difference between the anti-condensation power and the normal power being such large that, in the anti-condensation state of the housing, the power difference between the anti-condensation power and the normal power is less than the normal power. The relative humidity content in the housing (2) is lower than the relative humidity content in the housing (2) in the normal state, and wherein, in addition to the light sources (7, 14) of the light source unit (6), which are provided for generating a predetermined light distribution, the light sources (7, 14) of the light source unit (6), which are not provided for generating a light distribution, are provided.

Description

Technical Field

[0001] The present invention relates to a headlamp for a vehicle, wherein the headlamp has a housing, a light source unit is arranged in the housing, the light source unit has a plurality of light sources and an optical unit for generating a predetermined light distribution, the headlamp has a cover lens for closing a light exit opening of the housing, the headlamp has an operating unit for operating the light source, and the headlamp has an anti-condensation device for preventing condensation on the surface of the optical unit and / or the cover lens.

[0002] Furthermore, the invention relates to a method for avoiding condensation on a surface of an optical component of a headlight. Background Art

[0003] It is important for the function of the headlight that the humidity of the air in the interior of the headlight is not so great that condensation forms on the surfaces of the optical components, for example the cover lens, thereby affecting the light distribution generated by the headlight in an undesirable manner.

[0004] For example, it is known from DE 197 33 000 A1 to arrange a heating element close to the surface of an optical component so that this surface is always kept dry.

[0005] It is known from DE 10 2006 006 099 A1 to additionally provide a desiccant, by means of which the humidity content of the interior air is limited.

[0006] DE 10 2020 007 598 A1 discloses a headlamp for a vehicle, which has a housing in which a light source unit and an optical unit are arranged for generating a predetermined light distribution. The light source unit has a circuit board on which a plurality of LED light sources are arranged. The light exit opening of the housing is closed by a transparent cover lens. In order to avoid unwanted condensation on the cover lens, a plurality of infrared radiation sources are arranged on the circuit board as anti-condensation devices, and the LED light sources are also arranged on the circuit board. Both the LED light sources and the infrared radiation sources are arranged in a matrix on the circuit board. The LED light sources and the infrared radiation sources alternate in the row direction and the column direction. A disadvantage of this known headlamp is that, due to the integration of the infrared radiation source, the size of the light source unit is significantly increased, which has an adverse effect on the light guidance. Summary of the invention

[0007] It is therefore an object of the present invention to further develop a headlight for a vehicle and a method for avoiding condensation in such a way that undesired condensation on optical surfaces of the headlight can be avoided in a space-saving and simple manner.

[0008] In order to solve this task, the present invention is characterized in that, in combination with the preamble of claim 1, the control unit has a control program so that the light source unit operates at an anti-condensation power that is increased compared to a normal power set to produce a predetermined light distribution, wherein the power difference between the anti-condensation power and the normal power is so large that, in the anti-condensation state of the shell, the relative humidity content in the shell is lower than the relative humidity content in the shell in the normal state, wherein, in addition to turning on the light source of the light source unit that is set to produce the predetermined light distribution, the light source of the light source unit that is not set to produce the light distribution is also turned on.

[0009] Advantageously, the present invention makes it possible to simply avoid condensation on the optical surfaces of the headlight housing, wherein, on the one hand, no additional components are required and, on the other hand, no changes are required in the light guidance for generating the light distribution. The basic idea of ​​the present invention is to switch on light sources that are present and not required for the current driving situation (light distribution) in order to increase the heat output of the light source unit in this way, thereby avoiding undesired condensation on the optical surfaces of the headlight housing. In order to realize the present invention, the control unit for controlling the light sources of the light source unit has a control program so that, on the one hand, the light sources provided for generating a predetermined light distribution are switched on, and, on the other hand, the light sources not provided for generating this light distribution are additionally switched on, so that the light source unit does not operate at normal power, but at an increased anti-condensation power. This increased anti-condensation power leads to an increase in the heat output of the light source unit, which leads to avoiding condensation on the optical surfaces, in particular on the optical surfaces of the cover lens of the housing. Advantageously, unused parts of the light source unit can therefore be repurposed for anti-condensation.

[0010] According to a preferred embodiment of the invention, the light sources of the light source unit are controlled in such a way that during driving of the vehicle, in particular during daytime driving of the vehicle, at least some of the light sources that are not provided for generating the predetermined light distribution are switched on. If, for example, only the daytime running light function is to be generated as the predetermined light distribution during daytime driving, the light sources provided for generating the predetermined low-beam light distribution are additionally switched on. Advantageously, this involves a simple control, since only the number of light sources provided for the light function must be additionally switched on.

[0011] According to a further development of the invention, such a number of light sources that are not provided for the predetermined light distribution are switched on or actuated that the relative humidity in the interior of the housing is reduced by at least 10%, preferably by at least 30%, compared to a normal state, in which only the light sources for the predetermined light distribution are switched on. By continuously switching on the light sources that are not provided for the predetermined light distribution, the humidity level in the housing is kept at a relatively low level, thereby avoiding condensation on the optical surfaces, in particular when weather conditions change, which are accompanied by a sudden increase in humidity.

[0012] According to a further development of the invention, the light sources of the light source unit which are not provided for the predetermined light distribution are switched on for a predetermined anti-dew time period during the driving of the vehicle. If the driving time is longer than the anti-dew time period, the corresponding light source is switched off. The anti-dew time period is selected to be so long that condensation on the optical surface will not occur with a high probability.

[0013] According to a further development of the invention, when the vehicle is parked, the light source of the light source unit is switched on in order to limit the humidity content in the interior of the headlamp by means of its heat output. For example, the position light can be switched on in public areas. In private areas, such as in a garage, the light source for generating daytime running light and / or low beam light can be switched on.

[0014] According to a further development of the invention, a humidity sensor is arranged in the housing so that the humidity content of the interior can be determined. If the humidity value measured by the humidity sensor reaches a predetermined humidity threshold value, at least some of the light sources that are not provided for the current light distribution are switched on. Advantageously, the switch-on time of the light sources that are not provided for the predetermined light distribution, which is associated with the additional energy consumption, can thereby be reduced.

[0015] According to a further development of the invention, the control unit is coupled to a weather database and / or a position database and / or a season database so that the light sources of the light source unit are switched on for condensation prevention as a function of the current weather and / or the current position of the vehicle and / or the current season. This results in optimized condensation prevention, since, for example, if the weather database provides relatively current weather data with increased ambient humidity, the light sources that are not provided for the predetermined light distribution are switched on for a longer period of time. Seasonal information can be used, for example, to keep the light sources that are not provided for the light distribution switched on for a shorter period of time in dry winter than in humid summer.

[0016] To achieve this object, the method according to the invention has the features of claim 11 .

[0017] Advantageously, the method according to the invention enables the light source unit to be used not only to generate a predetermined light distribution but also for additional heat output in order to avoid condensation on the optical surfaces of the headlight housing. Advantageously, the light source unit remains unchanged and only the light sources which are not provided for light distribution are additionally actuated.

[0018] According to a further development of the method according to the invention, light sources not provided for light distribution are switched on according to weather data and / or location data and / or season data. In this way, the increased heat output of the light source unit can be optimized according to the current ambient conditions to avoid condensation.

[0019] According to a further development of the invention, the additional light source which is not currently provided for generating the predetermined light distribution is a light source which is provided in other operating states of the headlamp, i.e., for generating other light distributions. The additional light source can be provided, for example, for generating a partial light distribution, for example, a light distribution for a close range. Thus, the control effort for preventing condensation is relatively low, since no light source is provided for generating a non-predetermined light distribution.

[0020] According to a further development of the invention, the switch-on duration of the further light source is metered such that the current humidity content of the air in the interior of the headlamp is below a predetermined condensation threshold. Preferably, the switch-on duration is selected to be so long that the humidity content in the interior of the headlamp is always at a certain distance below the condensation threshold. By means of this safety distance, undesired condensation of the optical surface can be avoided with a high probability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

[0022] In the attached picture:

[0023] Figure 1 A block diagram of a headlamp according to a first embodiment of the present invention is shown.

[0024] Figure 2 The humidity variation curve of the inner space of the headlamp in a normal state and in a condensation state of the inner space is shown.

[0025] Figure 3 A block diagram showing a headlamp according to a second embodiment,

[0026] Figure 4 A block diagram of a headlamp according to a third embodiment is shown. DETAILED DESCRIPTION

[0027] According to the present invention Figure 1 The headlamp 1 of the first embodiment of the present invention comprises a housing 2 in which a first light module 3 and a second light module 4 are arranged. The light exit opening of the housing 2 is closed by a transparent cover lens 5 .

[0028] The first light module 3 has only one light source unit 6, which has a plurality of light sources 7 arranged in a matrix shape and which, when switched on, are used to generate a daytime running light distribution. The light sources 7 are arranged on a common circuit board 8. The light sources 7 are designed as LED light sources.

[0029] The second light module 4 is used to generate a low-beam light distribution and / or a high-beam light distribution. The second light module 4 has a light source unit 9 on the one hand and an optical unit 10 on the other hand. The optical unit 10 includes a lens 16 arranged in the light emission direction L of the headlamp 1 in front and on the side facing the cover lens 5. In addition, the optical unit 10 includes a first primary optical device 11 and a second primary optical device 12, the first primary optical device being assigned to a first part 13 of a plurality of light sources 14 arranged in a matrix shape, and the second primary optical device being assigned to a second part 15 of the light sources 14 combined in the light source unit 9. The first primary optical device 11 is designed so that the first part 13 of the light source 14 diffracts so that the light beam emitted by the first part 13 of the light source 14 is imaged by the lens 16 accordingly as a light distribution in the near field. The second primary optical device 12 is designed so that the light beam emitted by the second part 15 of the light source 14 is shaped by the lens 16 so that it is imaged by the lens 16 as a light distribution in the far field.

[0030] The second light module 4 is used to generate a low-beam light distribution as a first predetermined light distribution and to generate a high-beam light distribution as a second predetermined light distribution. If only the first part 13 of the light source 14 is switched on by the control signal 17 of the electronic control unit 18, a light distribution in the near field is generated as a low-beam light distribution. If the second part 15 of the light source 14 is additionally switched on, a high-beam light distribution is generated as a superposition of the light distributions in the near field and the far field.

[0031] In order to prevent condensation on the optical surfaces of the housing 2, in particular the cover lens 5, the control unit 18 has a control program 19, by means of which, in addition to switching on the light sources 7, 14 for generating a predetermined light distribution, another light source 14 that is not provided for the predetermined light distribution is also switched on. For example, the predetermined light distribution for daytime driving of the vehicle is the following daytime running light distribution, which is achieved by controlling or switching on the first light module 3. The control program 19 can be constructed in such a way that during daytime driving, the first part 13 of the light source 14 of the second light module 4 is additionally controlled or switched on, thereby achieving an increase in the heat output in the housing 2 (the interior space of the housing) compared to the normal state of the headlight in which only the first light module 3 is switched on. Figure 2, the humidity content in the headlamp 1 is shown in the state of switching off and switching on the first part 13 of the light source 14. If the first part 13 of the light source 14 is in the switched-off state, the humidity profile F1 is constant at a relative humidity of 0.7, for example, assuming ideal driving conditions. If the first part 13 of the light source 14 is switched on, a humidity profile F2 of the interior is obtained, which is significantly lower than the humidity profile F1 in the switched-off state. It is assumed that the first part 13 of the light source 14 is switched on during the entire daytime driving until the time point T1, from which the vehicle is placed in a parked state, in which the first part 13 of the light source 14 is switched off. It can be seen that after the switching-on process at the time point 0, the humidity content in the housing suddenly drops by ΔF. During the daytime driving, the humidity difference ΔF increases over time. After parking and switching off the first part 13 of the light source 14, the humidity rises in a sudden manner, wherein there is a second humidity difference ΔF2. The humidity difference decreases continuously over time.

[0032] It can be seen that by switching on the first part 13 of the light sources 14 which are not provided for the predetermined daytime running light distribution, the relative humidity content in the housing is significantly reduced. It can be seen that ΔF1 is in the range of 0.2, so that in the driving state of the vehicle, there is at least a 30% reduction in the humidity content, and after the end of the driving at the time T1, a 10% humidity reduction can still be achieved compared to the switched-off state according to F1.

[0033] The longer the driving lasts, the greater the humidity difference ΔF2 at the end of the driving. Figure 2 As shown in the graph in , the vehicle is in an anti-condensation state during driving, in which the anti-condensation power ΔF1 gradually increases compared to the normal power (the off state of the second optical module 4). After the end of driving at time point T1, the anti-condensation power gradually decreases and gradually approaches the normal power, while the humidity difference ΔF2 decreases. If the current humidity content F2 is not close to the humidity content F1 at the beginning of the next driving, the humidity content decreases by ΔF1, wherein the total difference ΔF relative to the humidity curve F1 is numerically larger. The more times you drive or the shorter the interval between each drive, the greater the humidity reduction or the higher the anti-condensation power can be achieved.

[0034] According to an alternative embodiment of the present invention, which is not shown, the anti-condensation state can also be limited to a certain duration. This is particularly suitable for user characteristics of users who drive relatively frequently over a period of time.

[0035] According to the present invention Figure 3In another embodiment of the invention, a humidity sensor 21 is fastened to a support frame 20 of the second light module 4, which surrounds the primary optics 11, 12 and the lens 16. The humidity signal of the humidity sensor is evaluated in the control unit 18. Depending on the humidity signal detected by the humidity sensor 21, the second light module 4 or the first part 13 of the light source unit 9 is additionally controlled during daytime driving.

[0036] According to the present invention Figure 4 In the third embodiment of the invention, the control unit 18 is connected to the weather database 22, the position database 23 and the season database 24. Alternatively, it can also be provided that the control unit 18 is coupled to only one or two of the aforementioned databases.

[0037] The weather database 22 provides current weather data or a weather forecast for the next day. The weather data may, for example, have relative humidity content data. If necessary, the humidity content data may also be calculated from the weather data. If the weather database 22 provides current weather data with a relatively high humidity above a humidity threshold, the first part 13 of the light source 7 is switched on during daytime driving. If the current weather data indicates that the air is relatively dry, i.e., has a relatively low humidity, the first part 13 of the light source 7 is not switched on during daytime driving. The weather data may be called up via a communication network, such as a mobile network, etc.

[0038] The position database 23 can extract position data from the navigation system of the vehicle. Typical humidity content values ​​can be recorded for each position or area in the position database. By comparing the current position of the vehicle with the list of humidity contents assigned to the corresponding position, it can be derived whether the first part 13 of the light source is switched on or off.

[0039] Season database 24 contains seasonal humidity experience values. The content of season database 24 can be combined with location database 23, so that a decision is made based on experience values ​​whether to switch on or off the first part 13 of light source 7 according to the current location and current season.

[0040] Reference numerals list

[0041] 1 headlight

[0042] 2 Housing

[0043] 3. First optical module

[0044] 4 Second optical module

[0045] 5 Cover the lens

[0046] 6 Light source unit

[0047] 7 Light Source

[0048] 8 Circuit Board

[0049] 9 Light source unit

[0050] 10 Optical unit

[0051] 11. First primary optical device

[0052] 12 Second primary optical device

[0053] 13 Part 1

[0054] 14 Light Source

[0055] 15 Part 2

[0056] 16 Lens

[0057] 17 Control Signal

[0058] 18 Control Unit

[0059] 19 Control Program

[0060] 20 Loading frame

[0061] 21 Humidity Sensor

[0062] 22 Weather Database

[0063] 23 Location Database

[0064] 24 Seasons Database

[0065] F1, F2 humidity change curve

[0066] T1 time point

[0067] ΔF, ΔF2 humidity difference

[0068] ΔF1 anti-condensation power

Claims

1. A headlamp for a vehicle, the headlamp comprising: a housing (2), a light source unit (9) arranged in the housing, the light source unit having a plurality of light sources (7, 14) and an optical unit (10) for generating a predetermined light distribution, the headlamp having a cover lens (5) closing a light exit opening of the housing (2), the headlamp having an operating unit (18) for operating the light sources (7, 14), and the headlamp having an anti-condensation device for preventing condensation on the surface of the optical unit (10) and / or the cover lens (5), characterized in that: The control unit (18) has a control program (19) so that the light source unit (6) operates at an anti-condensation power that is increased compared to a normal power set to produce a predetermined light distribution, wherein the power difference between the anti-condensation power and the normal power is so large that the relative humidity content in the shell (2) in the anti-condensation state of the shell is less than the relative humidity content in the shell (2) in the normal state, wherein, in addition to turning on the light source (7, 14) of the light source unit (6) that is set to produce the predetermined light distribution, the light source (7, 14) of the light source unit (6) that is not set to produce the light distribution is also turned on.

2. The headlamp according to claim 1, characterized in that: The control program (19) is designed so that during driving of the vehicle, in particular during daytime driving, at least some (13) of the light sources (14) which are not provided for generating a predetermined light distribution are switched on.

3. The headlamp according to claim 1 or 2, characterized in that: The control program (19) is designed so that the first part (13) of the light source (14) is controlled at an anti-condensation power so that the relative humidity in the housing (2) during the switched-on state is reduced by at least 10%, preferably at least 30%, compared to normal power.

4. The headlamp according to any one of claims 1 to 3, characterized in that: The control program (19) is designed so that the relative humidity (rH) in the housing (2) continuously decreases while the light source unit (6) is switched on and continuously increases after the light source unit (6) has been switched on.

5. The headlamp according to any one of claims 1 to 4, characterized in that: The control program (19) is designed so that the light source unit (6) is continuously controlled at an anti-condensation power for a predetermined period of time while the vehicle is driving in the switched-on state.

6. The headlamp according to any one of claims 1 to 5, characterized in that: The control program (19) is designed so that the light source unit (6) is controlled at an anti-condensation power when the vehicle is parked.

7. The headlamp according to any one of claims 1 to 6, characterized in that: The control unit (18) is coupled to a humidity sensor (21) arranged in the housing (2), and once the humidity sensor (21) provides a humidity measurement value greater than a predetermined humidity threshold, the light source unit (6) is controlled at an anti-dew power higher than a normal power.

8. The headlamp according to claim 7, characterized in that: The light source unit (6) and the optical unit (10) are fastened in a module housing or on a supporting frame (20), wherein the humidity sensor (21) is fastened on the module housing or on the supporting frame (20).

9. The headlamp according to any one of claims 1 to 8, characterized in that: The control unit (18) is coupled to a weather database (22) and / or a position database (23) and / or a season database (24) so ​​that a control signal for controlling the light source (7, 14) is generated according to the current weather and / or the current position and / or the current season.

10. The headlamp according to any one of claims 1 to 9, characterized in that: A plurality of light modules (3, 4) are provided, wherein a first light module (3) for generating daytime running light is provided and a second light module (4) for generating a light distribution in a near field and for generating a light distribution in a far field is provided, and when the vehicle is driving during the day, a light source (14) of the second light module (4) for generating a light distribution in the near field is switched on together with a light source (7) of the first light module (3).

11. A method for avoiding condensation on the surface of an optical component (5) of a headlamp (1) according to any one of claims 1 to 10, characterized in that In addition to switching on the light source (7), by means of which a predetermined light distribution is generated in the current driving state of the vehicle, a further light source (14) is also switched on, so that additional heat output of the light source units (6, 9) occurs.

12. The method according to claim 11, characterized in that The further light source (14) is switched on as a function of humidity sensor data detected in the housing interior of the headlamp (1) and / or as a function of current weather data and / or current position data of the vehicle and / or current season data.

13. The method according to claim 11 or 12, characterized in that: The further light source (14) serves, when switched on, to generate a predetermined partial light distribution or to generate an additional light distribution.

14. The method according to any one of claims 11 to 13, characterized in that The switch-on period of the further light source (14) is selected such that a current humidity value in the interior of the headlight housing (2) is below a condensation threshold value.

15. The method according to any one of claims 11 to 14, characterized in that The light sources (7, 14) are controlled such that the additional light source (14) is switched on while the vehicle is moving and / or while the vehicle is parked.

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