EP2210037B1 - Headlight for vehicles - Google Patents

Description

The invention relates to a headlight for vehicles according to the preamble of claim 1.

From the DE 10 2004 042 092 A1 A headlight for vehicles with a light module is known which has a plurality of LED light sources which are combined on a substrate to form an LED field. Furthermore, the headlight has a sensor device by means of which objects in the vehicle apron can be detected. The sensor device is connected to a control device which, depending on the sensor signal, controls individual LED light sources of the LED field in such a way that a light beam emitted by the light module has recess areas where an oncoming road user or road user driving ahead would be blinded. The known headlamp thus enables a light distribution to be generated which, with the exception of the cut-out area, illuminates a large part of the vehicle apron.

From the DE 102 42 864 A1 A control device for a headlamp is known in which evaluation electronics, depending on the brightness of the incident light, act on control electronics in such a way that this adjusts the light distribution in accordance with a motorway light distribution or a low beam distribution. The production of relatively wide and narrow light bundles is not known from this document.

From the EP 1 780 462 A a headlight for vehicles is known in which several LED light sources are used. The LED light sources are preceded by a light modulation device and a plurality of light guides and a converging lens in order to produce a low beam distribution. The light beams generated by the LED light sources can each be individually modulated. However, this is associated with a relatively high expenditure on control technology.

From the DE 10 2005 041 234 A1 A headlight for vehicles is known, which is a headlight for vehicles with a light module which has two groups of LED light sources for generating a motorway light distribution, each of which is combined in matrix form on a substrate to form an LED field. The LED fields are each preceded by an optical unit which has such a different imaging characteristic that light beams of different solid angles are emitted and produce light spots of different sizes on a measuring screen. The light module is thus designed to be relatively complex.
The object of the present invention is to develop a headlamp for vehicles in such a way that improved illumination of the vehicle apron is ensured in a simple manner without glare to road users located in the vehicle apron.

To achieve this object, the invention has the features of claim 1.

The particular advantage of the invention is that a light module is easily created which, in addition to a basic light distribution generated by a further light module, illuminates an enlarged vehicle apron area. Because several cells are provided, to which a common optical unit is assigned in such a way that at least two broad light beams can be generated, a light-dark boundary of the light distribution can be variably shifted in the vertical direction - depending on the current traffic situation. A first cell of the light module is used to generate a motorway light distribution, which is superimposed on a basic light distribution. According to the invention, the at least two cells of the light module and the optical unit are designed in such a way that at least two broad light beams are emitted, each of which strikes the vehicle apron at a horizontal critical angle of at least 8 ° and at a vertical critical angle of maximum 1 °. In this way, relatively wide light spots can advantageously be generated on a measuring screen, so that the superimposed ones are switched on arranged wide light spots the range of the illumination can be increased. Because the vertical limit angle is limited to a maximum of 1 °, the light-dark limit of the light distribution or the range of the light beam can be gradually increased or decreased.

According to a preferred embodiment of the invention, the optical unit is designed in such a way that the wide light beams emitted at different vertical angles are emitted by overlapping adjacent broad light beams. This advantageously results in a continuous transition when "switching on" or "switching off" cells of the light module, while the light-dark boundary has a relatively high luminance gradient.

According to a development of the invention, at least the first cell of the light module can be controlled in a dimmable manner, so that relatively "soft" transitions are created between the lowermost wide light beam and an upper edge of the basic light distribution or between the wide light beams. The overall light distribution is thus relatively homogeneous, with a relatively high luminance gradient only at the light-dark boundary.

According to a development of the invention, each cell of the light module has only a single LED chip. The upstream optical unit is designed in such a way that an “expansion” takes place in the horizontal direction of the light beam emitted by the respective LED chip and thus a relatively broad light spot is generated on the measuring screen.

According to an alternative embodiment, the cell can also be formed by a row of LED light sources, the number of rows of LED light sources corresponding to the number of wide light beams. The optical unit depicts the individual LED light sources so that pixel-like light sources are arranged in several horizontal rows on a measuring screen.

Further advantages of the invention result from the further subclaims.

An embodiment of the invention is explained below with reference to the drawings.

Fig. 1

ein Blockschaltbild eines Scheinwerfers und

Fig. 2

eine schematische Darstellung einer Lichtverteilung des Scheinwerfers auf einem Messschirm.

Show it:

Fig. 1

a block diagram of a headlamp and

Fig. 2

is a schematic representation of a light distribution of the headlamp on a measuring screen.

A headlight for vehicles essentially consists of a housing 1, in which at least a first light module 2 and a second light module 3 are arranged.

The first light module 2 consists of three cells A, B, C of light sources, each cell A, B, C having a single LED chip 4. The LED chip 4 can have, for example, a single LED or, for example, four common cast LEDs.

The LED chips 4 of the cells A, B, C are arranged on a common substrate 5. A common optical unit 6 is arranged in front of the cells A, B, C and scatters the light generated by the cells A, B, C into narrow, horizontally running light beams a, b and c, respectively. In the present exemplary embodiment, the light generated by the upper cell A is scattered into a first broad light bundle a to form a lower broad light spot 7, which strikes a measuring screen 18 at an angle of -0.28 ° below the horizontal H. The light generated by the middle cell B is scattered by means of the optical unit 6 in such a way that a second broad light bundle b is generated to form a middle broad light spot 8, which is arranged on the measuring screen 18 at least partially overlapping above the first broad light bundle a. A light generated by the lower cell C is the optical unit 6 is scattered in such a way that a further wide light beam c is imaged on the measuring screen to form an upper wide light spot 9.

The second light module 3 has an LED chip 11 as the light source, to which a second optical unit 10 is assigned to form a basic light distribution 12. The LED chip 11 or the second optical unit 10 is designed such that a low-beam light distribution with a Light-dark boundary HDG is formed, which has a 15 ° rise 13.

For improved illumination of the vehicle apron, cells A, B, C can be switched on or off in succession. For this purpose, cells A, B, C are controlled by means of a control device 14, which is coupled on the input side to a sensor device 15 on the one hand and to a switching device 16 on the other hand. The sensor device 15, which is preferably arranged outside the housing 1, is designed such that objects located in the front of the vehicle can be detected. For example, road users traveling ahead or oncoming can be identified and localized. The switching device 16 can be arranged, for example, in the cockpit of the vehicle, so that cells A, B, C can be switched on and off manually or depending on predetermined parameters.

In the present exemplary embodiment, the narrow light beams a, b, c have a horizontal critical angle α of at least 8 ° and a vertical critical angle β of a maximum of 1 °. The horizontal limit angle α is understood to mean the opening angle of the corresponding light beam in the horizontal direction and the vertical limit angle β is the opening angle of the corresponding light beam in the vertical direction.

In the present exemplary embodiment, the horizontal critical angle α of the light bundles a, b, c is 10 °, the wide light spots 7, 8, 9 formed being arranged symmetrically to a vertical V. The vertical critical angle β of the light bundles a, b, c is approximately 0.3 °, so that the lower light bundle a is used to generate a motorway light distribution serves. The lower light spot 7 generated by the lower light bundle a extends overlapping to a horizontal cut-off line HDG of the low-beam light distribution 12. The freeway light can take place, for example, by dimmed switching on of the cell A, so that the vehicle apron illumination can be expanded homogeneously. Depending on the position of objects in the front of the vehicle, the other cells B and C can then be switched on or off. This connection or disconnection can also be made dimmable. The electrically switchable activation of the cells A, B, C enables a "cross-fading" of an upper edge region 17 of the basic light distribution, which adaptively adapts the cut-off line HDG of the resulting light distribution to the current traffic situation.

The LED chips 11 of the cells A, B, C or the optics unit 6 are preferably designed such that when the cells A, B, C are switched on, an overlap of adjacent broad light spots 7, 8, 9 occurs. How from Figure 2 it can be seen, the wide light spots 7, 8, 9 have the same contour, so that the wide light beams a, b, c have the same horizontal critical angle α and vertical critical angle β.

According to an alternative embodiment of the cells A, B, C, each of these can also be formed by a row of LED chips 4, the optical unit 6 imaging the light emitted by the respective rows of LED chips 4 into pixel-like light spots which are in a horizontal row are arranged. This row of light spots corresponds in each case to the wide light spots 7, 8, 9 when the cells A, B, C are implemented with the respective single LED chips 4.

Reference list

1

casing

2nd

first light module

3rd

second light module

4th

LED chip

5

Substrate

6

Optical unit

7

lower broad spot of light

8th

medium wide light spot

9

upper broad spot of light

10th

second optical unit

11

LED chip

12th

Basic light distribution

13

15 ° rise

14

Control device

15

Sensor device

16

Switching device

17th

Edge area

18th

Measuring screen

A, B, C

Cells

a, b, c

Beam of light

H

horizontal

HDG

Cut-off line

V

vertical

α

horizontal critical angle

β

vertical critical angle

Claims (8)

1. Headlamp for vehicles with a first light module (2) containing a plurality of LED light sources (4) and an optical unit (6) allocated to the LED light sources (4) with a sensor device (15) for detecting an object located in the area ahead of the vehicle with a control device (14) that, depending on a sensor signal provided by the sensor device (15) and/or on a switching signal of a switching device (16), actuates the first light module (2) for emitting a first specified light beam (a, b, c), where the first light module (2) features a first cell (A) containing at least one LED light source (4) such that in interaction with the optical unit (6) a first wide light beam (a) is generated for creating a highway light distribution (7), where the first light module (2) features at least a one second cell (B, C) containing at least one LED light source (4), so that in interaction with the same optical unit (6) at least one further wide light beam (b, c) can be created that joins on immediately above the first wide light beam (a) and that the first cell (A) and the at least one further cell (B, C) is formed either by a single LED chip (4) or a series of LED chips and that the optical unit (6) features such imaging characteristics that the first wide light beam (a) and the at least one further light beam (b, c) is emitted at a horizontal critical angle (a) of at least 8°, characterized in that the optical unit (6) of the first light module (2) features such imaging characteristics that the first wide light beam (a) and that the at least one further light beam (b, c) is emitted at a vertical critical angle (β) of a maximum of 1° and that the optical unit (6) of the first light module (2) is formed in such a way that a second light module (3) containing an LED light source (11) and an optical unit (10) is provided for with a view to creating a low-beam light distribution with a light-dark cut-off line (HDG) as a basic light distribution.
2. Headlamp in accordance with Claim 1, characterized in that at least the first cell (A) of the first light module (2) can be actuated in such a way that it is dimmable.
3. Headlamp in accordance with Claim 1 or 2, characterized in that the optical unit (6) of the first light module (2) is formed in such a way that the first wide light beam (a) and the further wide light beam (b, c) feature the same horizontal and/or vertical critical angle (a ,β).
4. Headlamp in accordance with one of Claims 1 through 3, characterized in that the optical unit (6) of the first module (2) is formed in such a way that the wide light beams (a, b, c) are arranged one above the other on a measuring screen (18) while forming an overlapping of adjacent light beams (a, b, c).
5. Headlamp in accordance with one of Claims 1 through 4, characterized in that the optical unit (6) of the first light module (2) is formed in such a way that the first wide light beam (a) is arranged at a vertical angle of -0.28° to the horizontal (H) on the measuring screen (18).
6. Headlamp in accordance with one of Claims 1 through 5, characterized in that the light patch (7) formed by the first wide light beam (a) is arranged so that it overlaps an upper edge (17) of the basic light distribution (12).
7. Headlamp in accordance with one of Claims 1 through 6, characterized in that the cells (A, B, C) of the first light module (2) are arranged adjacent to each other in a vertical direction.
8. Headlamp in accordance with one of Claims 1 through 7, characterized in that the cells (A, B, C) of the first light module (2) are actuated by means of the control device (14) in such a way that the light-dark cut-off line (HDG) of the basic light distribution (12) is modified depending on the traffic situation in a vertical direction determined by means of the sensor device (15).

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