Headlight and headlight system for a motor vehicle

Abstract

Headlight for a motor vehicle, with a first projection device (12) for illuminating a wide area (18) and a second projection device (14) laterally offset from the first projection device (12) for illuminating a narrow area (20) located within the wide area (18), wherein an intensity profile (22) of the light emitted by the first projection device (12) and an intensity profile (24) of the light emitted by the second projection device (14) are coordinated with one another in the lateral direction such that in at least one lateral edge region of the narrow surface (20) there is a gradual transition to the intensity in the wide surface (18) outside the narrow surface (2) and a substantially constant intensity between the lateral edge regions of the narrow surface (20) within the narrow surface (20), wherein the intensity curves (22, 24) of the first projection device (12) and the second projection device (14) are designed for a shorter distance than a projection distance designated for the wide area (18) and the narrow area (20).

Description

[0001] The invention relates to a headlight and a headlight system for a motor vehicle, with the aid of which an illumination area in front of the motor vehicle can be well illuminated.

[0002] From DE 10 2017 114 903 A1 it is known that in a headlight with two different light point sources, those light points of the respective light point source that would not overlap with a light point of the other light point source on a projection surface can be switched off in order to be able to project a particularly sharp and high-contrast symbol.

[0003] From DE 10 2016 221 918 A1, an ambient lighting system for a motor vehicle is known in which a light generated in a light source is emitted via a field with a plurality of different lenses, wherein a light field emitted via a small lens is directed into a more distant area of ​​a light field emitted by a larger lens in order to compensate for a decreasing brightness intensity in the more distant area.

[0004] From DE 10 2016 210 645 A1 it is known to make switching between a low beam and a high beam in a motor vehicle gradual and less abrupt over several intermediate states.

[0005] From DE 10 2017 129 254 A1 a headlight for a motor vehicle is known in which two LED light modules with a dynamically controllable light distribution are provided, of which a light pattern with a narrow light distribution of one LED light module lies completely within the light pattern with a wide light distribution of the other LED light module.

[0006] There is a constant need to illuminate the area in front of the vehicle well.

[0007] The object of the invention is to show measures that enable a well-lit lighting area in front of a motor vehicle.

[0008] The object is achieved according to the invention by a headlight having the features of claim 1, a headlight system having the features of claim 9 and a headlight system having the features of claim 10. Preferred embodiments of the invention are specified in the subclaims and the following description, which may each individually or in combination represent an aspect of the invention.

[0009] One aspect of the invention relates to a headlight for a motor vehicle, comprising a first projection device for illuminating a wide area and a second projection device laterally offset from the first projection device for illuminating a narrow area located within the wide area, wherein an intensity profile of the light emitted by the first projection device and an intensity profile of the light emitted by the second projection device are coordinated with one another in the lateral direction such that in at least one lateral edge region of the narrow area there is a gradual transition to the intensity in the wide area outside the narrow area and a substantially constant intensity between the lateral edge regions of the narrow area within the narrow area,wherein the intensity profiles of the first projection device and the second projection device are designed for a shorter distance than a projection distance designated for the wide area and the narrow area.,

[0010] The projection devices, which are provided in particular within a common headlight housing, can be designed to generate at least part of an illumination area intended for a low beam and / or a high beam. The shape and intensity, in particular the illuminance specified in lux, of the illumination of the illumination area of ​​a low beam and / or a high beam is generally regulated by legal requirements in a regulation. In order to be able to project the illumination area intended for the low beam and / or the high beam with the aid of the headlight, the projection devices of the respective headlight can emit visible light with a specific intensity, in particular the luminous intensity specified in candelas, and can emit the emitted light with a designated shape of the illumination area using suitable measures, for example diaphragms.The respective projection device preferably comprises a plurality of lighting elements, in particular configured as LEDs, which are preferably arranged in a matrix-like manner in rows and columns. This makes it possible to achieve a desired shape and / or intensity for the illumination area by appropriately controlling the respective lighting elements.

[0011] For example, the illumination area in a section of the road in front of the motor vehicle should be illuminated as brightly as possible to the extent permitted by the regulations, while in adjacent areas, for example in the oncoming lane or at the edge of the road, a lower intensity of brightness is desired in order not to dazzle other people. To this end, the first projection device can be used to illuminate a wide area, which can extend far enough in the lateral direction and / or vertically or in the direction of travel to also cover the areas illuminated for lesser brightness. The second projection device can illuminate a narrower area, where the intensities of the visible light emitted by the first projection device and the second projection device can overlap.To ensure that the doubly illuminated area in the narrow area does not reach an excessive illuminance, the light intensities of the respective projection devices can be appropriately adjusted to each other, in particular by controlling the lighting elements of the respective projection devices accordingly using a control device. At the same time, the control device provided can also prevent a hard light / dark boundary and a sharp jump in intensity between the narrow area and the part of the wide area lying outside the narrow area, thereby improving the visual perception of a motor vehicle driver in the darker areas of the illuminated area.

[0012] However, it has been shown that optical errors can occur in the close range shortly in front of the motor vehicle. These errors are caused by the lateral offset of the first projection device relative to the second projection device and the illumination area designed for a specific projection distance. If, for example, when cornering and / or driving uphill, the illumination area generated by the motor vehicle's headlights does not hit the ground at the designated projection distance designed for a horizontal surface, but at a significantly shorter distance, particularly bright and particularly dark stripes can appear in the illumination area because the intensity profiles of the projection devices designed for the designated projection distance would no longer overlap correctly as intended.

[0013] To avoid these optical errors, the intensity curves of the projection devices are not designed for an illumination area occurring on a horizontal surface at the designated projection distance, but rather for an illumination area occurring at a distance shorter than the designated projection distance. If the illumination area is projected at a shorter distance than the designated projection distance, optical errors are avoided, ensuring that the driver's visual perception remains good even in such situations and is not impaired by any optical effects that may occur. This improves driving safety in the dark.

[0014] In this case, a suboptimal intensity distribution at the designated projection distance is deliberately accepted. This is based on the realization that any impairment of the desired intensity distribution becomes less and less significant with increasing distance, since the lateral offset of the projection devices is increasingly leveled out and becomes less relevant as the distance increases. In addition, the driver of the vehicle can perceive fewer and fewer details as the distance increases, so that an impaired intensity distribution in more distant areas of the illumination field becomes less relevant for the driver. In contrast, the driver should have particularly good visibility, not least for safety reasons, in situations that appear particularly close to the vehicle and are illuminated by the headlights, in order to be able to quickly assess the situation correctly and react appropriately.By designing the intensity curves at a distance that is actually too short, a significant improvement in optical perception can be achieved with an essentially negligible impairment of the intensity curve at the designated projection distance in a particularly safety-critical close range, thus enabling a well-illuminated lighting area in front of a motor vehicle over a particularly large distance range.

[0015] With low beam, the illumination range in a passenger car is typically 100 times the mounting height of the headlight when installed. The designated projection distance is therefore essentially 100 times the mounting height of the headlight in the vehicle. With a mounting height of 65 cm, the illumination range extends 65 m, and the designated projection distance is 65 m.

[0016] In particular, the distance d for which the intensity curves of the first projection device and the second projection device are designed, based on a projection distance S A for low beam 0.40 ≤ d / S A ≤ 0.95, in particular 0.50 ≤ d / S A ≤ 0.90, preferably 0.60 ≤ d / S A ≤ 0.85 and particularly preferably 0.70 ≤ d / S A ≤ 0.80. With such an offset in the direction of travel of the distance d for the optimal intensity profile of the illumination area to the nominal designated projection distance S A For the low beam, no significant optical aberrations are expected at the designated projection distance that would impair the driver's visual perception. At the same time, the safety-critical near area in front of the vehicle can be sufficiently illuminated without significant optical aberrations.

[0017] Preferably, the intensity profiles of the first projection device and the second projection device are designed to be laterally displaceable and / or laterally expandable depending on a measured variable. This makes it possible to identify, with the aid of the measured variable, specific situations in which, at a specific distance deviating from the designated projection distance, good illumination of the illumination area is advantageous, if possible without any optical errors. In this case, it may already be sufficient for the profile of the intensity profile to be laterally displaced and / or proportionally expanded using a lighting device controlling the lighting elements of the first projection device and / or the second projection device. The intensity profile and the illumination of the illumination area can thus be dynamically adapted to changing circumstances, achieving good illumination without any optical errors.

[0018] Particularly preferably, a driving speed of a motor vehicle having the headlight and / or a measured actual projection distance are provided as the measured variable. At high driving speeds, for example when driving on a motorway, objects suddenly appearing in the immediate vicinity of the motor vehicle are not to be expected, since they can already be seen from a great distance away from the motor vehicle, so that a good intensity curve at a greater distance, i.e. in the range of the designated projection distance or even further away, is advantageous. At low driving speeds, it can be assumed that the driver wants to achieve a particularly short braking distance for safety reasons, so that a good intensity curve of the illumination area at a distance that is significantly shorter than the designated projection distance, in line with the driving speed.Preferably, the three-dimensional area in front of the motor vehicle can be scanned, for example, using a distance sensor, so that the actual projection distance, which may differ from the designated projection distance, can be measured and the intensity profile can be dynamically adjusted to the actual projection distance. Optical aberrations in the illumination area can thus be minimized.

[0019] In particular, the first projection device and the second projection device each have a plurality of separately controllable lighting elements, wherein the lighting duration of the respective lighting element and / or the lighting start time of different lighting elements can be adjusted relative to one another to adjust the intensity profile. By individually controlling each individual lighting element, the shape and intensity of the illuminated area can be adjusted almost arbitrarily and thus also adapted to changing situations.

[0020] Preferably, the first projection device and the second projection device are designed essentially identically, in particular as identical parts, with different focusing optics being provided for the first projection device and the second projection device. This allows manufacturing costs to be kept low. For the different focusing optics, for example, different lenses with different focal lengths arranged in the beam path of the respective projection device can be provided.

[0021] Particularly preferred is a ratio of the wide area A w to the narrow area A e 1.5 ≤ A w / A e ≤ 8.0, especially 2.0 ≤ A w / A e ≤ 6.0 and preferably A w / A e= 4.0 ± 0.5. With such a ratio, the illuminance levels specified in a regulation for the lighting area can be easily maintained and sufficient brightness can be achieved both in the narrow area and in the part of the wide area provided outside the narrow area.

[0022] In particular, a lateral offset v of an edge of the first projection device facing the second projection device to an edge of the second projection device facing the first projection device is 2.0 cm ≤ v ≤ 20.0 cm, in particular 5.0 cm ≤ v ≤ 15.0 cm, preferably v = 10.0 cm ± 1.0 cm. With such an offset, sufficient cooling of the lighting elements of the projection devices can be achieved with a small installation space requirement. In particular, it is possible to select the lateral offset to be large enough that cooling of the lighting elements by natural convection is sufficient. Significant optical errors caused by a correspondingly large offset are not to be feared due to the design of the intensity curves for a shorter distance.

[0023] A further aspect of the invention relates to a headlight system for a motor vehicle with a left headlight, which can be designed and developed as described above, and a right headlight, which can be designed and developed as described above, wherein the wide area or the wide area and the narrow area of ​​the left headlight and the right headlight overlap at a designated projection distance, wherein an intensity profile of the light emitted by the left headlight and an intensity profile of the light emitted by the right headlight are coordinated with one another in the lateral direction in such a way thatthat in at least one lateral edge region of the respective narrow area there is a gradual transition to the intensity in the wide area outside the narrow area and a substantially constant intensity between the mutually outer lateral edge regions of the respective narrow area within the narrow areas,The intensity profiles of the left and right headlights are designed for a shorter distance than the projection distance designated for the wide area and the narrow area. Even with overlapping illumination areas of the left and right headlights, a significant improvement in visual perception can be achieved by designing the intensity profiles for a distance that is actually too short, with an essentially negligible impairment of the intensity profile at the designated projection distance in a particularly safety-critical close range, thus enabling a well-illuminated illumination area in front of a motor vehicle over a particularly large distance range.

[0024] An independent aspect of the invention relates to a headlight system for a motor vehicle with a left headlight and a right headlight, wherein the left headlight and the right headlight each have a first projection device for illuminating a wide area and a second projection device laterally offset from the first projection device for illuminating a narrow area located within the wide area, wherein the wide area or the wide area and the narrow area of ​​the left headlight and the right headlight overlap at a designated projection distance, wherein an intensity profile of the light emitted by the left headlight and an intensity profile of the light emitted by the right headlight are coordinated with one another in the lateral direction in such a way thatthat in at least one lateral edge region of the respective narrow area, there is a gradual transition to the intensity in the wide area outside the narrow area and a substantially constant intensity between the mutually outer lateral edge regions of the respective narrow area within the narrow areas, wherein the intensity curves of the left headlight and the right headlight are designed for a shorter distance than a projection distance designated for the wide area and the narrow area.

[0025] Even if the intensity curves of the projection devices within the respective headlight are designed for the designated projection device, it is possible to achieve a comparable effect by adjusting the intensity curves of the illumination area of ​​the respective headlight as a whole, analogous to the above-described adjustment of the intensity curves of the respective projection devices within the individual headlight. The above-described explanations regarding the respective projection device therefore apply analogously to the left and right headlights.Even in the case of overlapping illumination areas of the left headlight and the right headlight, a significant improvement in optical perception can be achieved by designing the intensity curves at a distance that is actually too short, with an essentially negligible impairment of the intensity curve in the designated projection distance in a particularly safety-critical close range, whereby a well-illuminated illumination area in front of a motor vehicle is possible over a particularly large distance range.

[0026] The invention will be explained below by way of example with reference to the accompanying drawings using preferred embodiments, wherein the features presented below can represent an aspect of the invention both individually and in combination. They show: Fig. 1: a schematic representation of an intensity curve designed for a designated projection distance of Projection devices of a headlight at the designated projection distance, Fig. 2: a schematic representation of an intensity curve of projection devices of a headlight designed for a shorter distance than the designated projection distance at the designated projection distance and Fig. 3: a schematic representation of an intensity curve of projection devices of a headlight at a shorter distance than the designated projection distance.

[0027] The Fig. 1, only partially shown, can be used as the left or right headlight of a motor vehicle to illuminate an illumination area in front of the motor vehicle, in particular as low beam and / or high beam. The headlight 10 has a first projection device 12 comprising a plurality of matrix-shaped lighting elements configured as LEDs, and a second projection device 14 comprising a plurality of matrix-shaped lighting elements configured as LEDs, which are arranged laterally spaced from one another in a common headlight housing 16 of the headlight 10. The first projection device 12 illuminates a wide area 18, while the second projection device 14 illuminates a narrow area 20 lying entirely within the wide area 18, such that the narrow area 20 is illuminated more brightly than a part of the wide area 18 lying outside the narrow area 20.By appropriately controlling the lighting elements of the respective projection device 12, 14, the intensity, in particular the illuminance and / or light intensity, of the projection devices 12, 14 can have a profile transverse to the direction of travel such that a sharp jump in brightness at the lateral edge of the narrow surface 20 is avoided. For this purpose, for example, the intensity of the first projection device 12 can decrease from the outside to the inside, while the intensity of the second projection device 14 increases, so that with a corresponding overlap of the intensities in a lateral edge region of the narrow surface 20, a gradual intensity transition results, which does not significantly impair the visual perception of a driver of the motor vehicle.

[0028] However, if a first intensity curve 22 of the first projection device 12 and a second intensity curve 24 of the second projection device 14 are designed for the designated projection distance intended, for example, for low beam, as shown in Fig. 1, the lateral offset of the projection devices 12, 14 results in optical errors, in particular dark and light vertical stripes, if, due to obstacles, uphill driving or other situations, the illumination area illuminated by the projection devices 12, 14 only extends over a shorter distance than the designated projection distance.

[0029] In order to avoid such optical errors, the intensity curves 22, 24 of the projection devices 12, 14 are deliberately designed for a shorter distance, for example by shifting the intensity curves 22, 24 slightly towards the center of the surfaces 18, 20, as shown in Fig. 2. If the projection devices 12, 14 only generate an illumination area over a shorter distance than the designated projection distance and the wide area 18 and the narrow area 20 are therefore projected over a shorter distance, smaller areas result for the wide area 18 and the narrow area 20, for which, however, the intensity curves 22, 24 deliberately designed for a shorter distance provide optimal illumination given the unchanging lateral offset of the projection devices 12, 14 relative to one another.

[0030] At the Fig.3, essentially no optical errors are noticeable to the driver with this design of the intensity curves 22, 24. Furthermore, a difference between possibly suboptimal illumination and optimal illumination at the designated projection distance is barely noticeable to the driver, since the driver can hardly perceive such differences at the comparatively long designated projection distance. By designing the intensity curves 22, 24 for a distance that is actually too short, a significant improvement in optical perception can be achieved with an essentially negligible impairment of the intensity curve at the designated projection distance in a particularly safety-critical close range, thereby enabling a well-illuminated illumination area in front of a motor vehicle over a particularly large distance range.

Claims

[1] Headlight for a motor vehicle, with a first projection device (12) for illuminating a wide area (18) and a second projection device (14) laterally offset from the first projection device (12) for illuminating a narrow area (20) located within the wide area (18), wherein an intensity profile (22) of the light emitted by the first projection device (12) and an intensity profile (24) of the light emitted by the second projection device (14) are coordinated with one another in the lateral direction such that in at least one lateral edge region of the narrow surface (20) there is a gradual transition to the intensity in the wide surface (18) outside the narrow surface (2) and a substantially constant intensity between the lateral edge regions of the narrow surface (20) within the narrow surface (20), wherein the intensity curves (22, 24) of the first projection device (12) and the second projection device (14) are designed for a shorter distance than a projection distance designated for the wide area (18) and the narrow area (20). [2] Headlight according to claim 1 characterized by that for the distance d, for which the intensity curves (22, 24) of the first projection device (12) and the second projection device (14) are designed, relative to a projection distance S A for low beam 0.40 ≤ d / S A ≤ 0.95, in particular 0.50 ≤ d / S A ≤ 0.90, preferably 0.60 ≤ d / S A ≤ 0.85 and particularly preferably 0.70 ≤ d / S A ≤ 0.80 applies. [3] Headlight according to claim 1 or 2 characterized bythat the intensity curves (22, 24) of the first projection device (12) and the second projection device (14) are designed to be displaceable in the lateral direction and / or stretchable in the lateral direction depending on a measured variable. [4] Headlight according to claim 3 characterized by that a driving speed of a motor vehicle having the headlight (10) is provided as the measured variable and / or a measured actual projection distance is provided as the measured variable. [5] Headlight according to one of claims 1 to 4 characterized by in that the first projection device (12) and the second projection device (14) each have a plurality of separately controllable lighting elements, wherein a lighting duration of the respective lighting element and / or a lighting start of different lighting elements can be adjusted relative to one another in order to adjust the intensity profile (22, 24). [6] Headlight according to one of claims 1 to 5 characterized bythat the first projection device (12) and the second projection device (14) are designed essentially similarly, in particular as identical parts, wherein different focusing optics are provided for the first projection device (12) and the second projection device (14). [7] Headlight according to one of claims 1 to 6 characterized by that for a ratio of the wide area A w to the narrow area A e 1.5 ≤ A w / A e ≤ 8.0, especially 2.0 ≤ A w / A e ≤ 6.0 and preferably A w / A e = 4.0 ± 0.5 applies. [8] Headlight according to one of claims 1 to 7 characterized bythat a lateral offset v of an edge of the first projection device (12) facing the second projection device (14) to an edge of the second projection device (14) facing the first projection device (12) is 2.0 cm ≤ v ≤ 20.0 cm, in particular 5.0 cm ≤ v ≤ 15.0 cm, preferably v = 10.0 cm ± 1.0 cm. [9] Headlight system for a motor vehicle with a left headlight according to one of claims 1 to 8 and a right headlight according to one of claims 1 to 8, wherein the wide surface (18) or the wide surface (18) and the narrow surface (20) of the left headlight and the right headlight overlap at a designated projection distance, wherein an intensity profile (22, 24) of the light emitted by the left headlight and an intensity profile (22, 24) of the light emitted by the right headlight are coordinated with one another in the lateral direction in such a way that in at least one lateral edge region of the respective narrow area (20) there is a gradual transition to the intensity in the wide area (18) outside the narrow area (20) and a substantially constant intensity between the mutually outer lateral edge regions of the respective narrow area (20) within the narrow areas (20), wherein the intensity curves (22, 24) of the left headlight and the right headlight are designed for a shorter distance than a projection distance designed for the wide area (18) and the narrow area (20). [10] Headlight system for a motor vehicle with a left headlight and a right headlight, wherein the left headlight and the right headlight each have a first projection device (12) for illuminating a wide area (18) and a second projection device (14) laterally offset from the first projection device (12) for illuminating a narrow area (20) lying within the wide area wherein the wide area (18) or the wide area (18) and the narrow area (20) of the left headlight and the right headlight overlap at a designated projection distance, wherein an intensity profile of the light emitted by the left headlight and an intensity profile of the light emitted by the right headlight are coordinated with one another in the lateral direction in such a way that in at least one lateral edge region of the respective narrow surface (20) there is a gradual transition to the intensity in the wide surface (18) outside the narrow surface (20) and a substantially constant intensity between the mutually outer lateral edge regions of the respective narrow surface (20) within the narrow (20) surfaces, wherein the intensity curves of the left headlight and the right headlight are designed for a shorter distance than a projection distance designed for the wide area (18) and the narrow area (20).

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