Lighting Unit And Motor Vehicle Lighting Device With Such A Lighting Unit

Abstract

The invention relates to a lighting unit for use in conjunction with a light module of a motor vehicle lighting device. The light module is designed to produce a dimmed light distribution with a substantially horizontal cut-off line. The lighting unit has a light source that can be switched independently from the light module and an optical assembly that is assigned to the light source and is designed to deflect light emitted by the light source and to generate overhead lighting with a defined level of illumination which is spatially limited at least towards an oncoming traffic side in an overhead area above the cut-off line of the dimmed light distribution.

Claims

1. A lighting unit for use together with a light module of a motor vehicle lighting device, wherein the light module is designed to produce a dimmed light distribution with a substantially horizontal cut-off line, said lighting unit comprising: a light source that can be switched independently from the light module and an optical assembly associated with the light source, said optical assembly designed to deflect light emitted by the light source of the lighting unit to produce an overhead illumination with a defined illumination level which is spatially limited at least towards an oncoming traffic side in an overhead area above the cut-off line of the dimmed light distribution.

2. The lighting unit as set forth in claim 1, wherein the light source of the lighting unit is designed to be activated at least whenever the light module produces the dimmed light distribution.

3. The lighting unit as set forth in claim 1, wherein the optical assembly is designed to illuminate, with the overhead lighting, a measuring area in the overhead area where a minimum luminous intensity is required, so that the requirements for the minimum luminous intensity in the overhead area of the dimmed light distribution are fulfilled.

4. The lighting unit as set forth in claim 3, wherein the measuring area includes measuring points for minimum luminous intensities 2U 4L; 1.5U 1R to 3R required by standard according to FMVSS No. 108 Low Beam in the version in force on the priority date of the present application.

5. The lighting unit as set forth in claim 1, wherein the optical assembly is designed to omit, with the overhead illumination, a glare area on the oncoming traffic side of the dimmed light distribution, in particular in a region of 8 to 20 horizontally.

6. The lighting unit as set forth in claim 1, wherein the optical assembly is designed to omit, with the overhead lighting, measuring points 0.5U 1R to 3R in accordance with FMVSS No. 108 Low Beam in the version in force on the priority date of the present application or to illuminate these measuring points only with low luminous intensity.

7. The lighting unit as set forth in claim 1, wherein the optical assembly comprises a lens system with at least one lens or a reflection system with at least one reflector or a diffusing optics.

8. A motor vehicle lighting device comprising: a housing and a light module arranged therein for producing a dimmed light distribution with a substantially horizontal cut-off line, an additional lighting unit arranged in the housing, with a light source that can be switched independently from the light module and an optical assembly associated with the light source, which is designed to deflect light from the light source of the additional lighting unit to produce an overhead illumination with a defined level of illumination, which is spatially limited at least towards an oncoming traffic side, in an overhead region above the cut-off line of the dimmed light distribution.

9. The motor vehicle lighting device as set forth in claim 8, wherein the light source of the lighting unit is designed to be activated at least whenever the light module produces the dimmed light distribution.

10. The motor vehicle lighting device as set forth in claim 8, wherein the additional lighting unit is rigidly coupled to the light module and is movable therewith in respect to the housing of the motor vehicle lighting device.

11. The motor vehicle lighting device as set forth in claim 8, wherein the light module is designed to produce an adaptive driving beam which includes a glare-free high beam, and wherein the light source of the additional lighting unit is designed to be activated at least whenever the light module, in the course of generating the glare-free high beam, shades at least part of the overhead area.

12. The motor vehicle lighting device as set forth in claim 11, wherein the light module is in the form of a digital projector, a DMD-module or a micro-LED-module.

13. The lighting unit as set forth in claim 2, wherein the optical assembly is designed to illuminate, with the overhead lighting, a measuring area in the overhead area where a minimum luminous intensity is required, so that the requirements for the minimum luminous intensity in the overhead area of the dimmed light distribution are fulfilled.

14. The lighting unit as set forth in claim 13, wherein the measuring area includes measuring points for minimum luminous intensities 2U 4L; 1.5U 1R to 3R required by standard according to FMVSS No. 108 Low Beam in the version in force on the priority date of the present application.

15. The lighting unit as set forth in claim 5, wherein the optical assembly is designed to omit, with the overhead lighting, measuring points 0.5U 1R to 3R in accordance with FMVSS No. 108 Low Beam in the version in force on the priority date of the present application or to illuminate these measuring points only with low luminous intensity.

16. The motor vehicle lighting device as set forth in claim 8, wherein the additional lighting unit is designed to illuminate, with the overhead lighting, a measuring area in the overhead area where a minimum luminous intensity is required, so that the requirements for the minimum luminous intensity in the overhead area of the dimmed light distribution are fulfilled.

17. The motor vehicle lighting device claim 8, wherein the additional lighting unit is designed such that the measuring area includes measuring points for minimum luminous intensities 2U 4L; 1.5U 1R to 3R required by standard according to FMVSS No. 108 Low Beam in the version in force on the priority date of the present application.

18. The motor vehicle lighting device as set forth in claim 8, wherein the optical assembly is designed to omit, with the overhead illumination, a glare area on the oncoming traffic side of the dimmed light distribution, in particular in a region of 8 to 20 horizontally.

19. The motor vehicle lighting device as set forth in claim 8, wherein the optical assembly is designed to omit, with the overhead lighting, measuring points 0.5U 1R to 3R in accordance with FMVSS No. 108 Low Beam in the version in force on the priority date of the present application or to illuminate these measuring points only with low luminous intensity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

[0034] FIG. 1 shows an overhead lighting of a dimmed light distribution according to the US standard, known from the prior art;

[0035] FIG. 2 shows a motor vehicle headlamp known from the prior art, with a projection lens with a prism for producing an overhead lighting;

[0036] FIG. 3 shows an overhead lighting known from the prior art with a digital light distribution of a digital projector, a DMD- or a LED-module;

[0037] FIG. 4 shows a first perspective schematic view of a lighting unit according to the invention for generating an overhead lighting according to a preferred embodiment;

[0038] FIG. 5 shows a second perspective view of the lighting unit from FIG. 4;

[0039] FIG. 6 shows a side view of the lighting unit from FIG. 4;

[0040] FIG. 7 shows a plan view opposite to a light exit direction, of the lighting unit from FIG. 4;

[0041] FIG. 8 shows an overhead lighting according to the invention in accordance with a preferred embodiment; and

[0042] FIG. 9 shows a plan view opposite to the light exit direction, of a light module of a motor vehicle headlamp according to the invention, with a lighting unit according to the invention coupled to the light module.

DETAILED DESCRIPTION OF THE INVENTION

[0043] In headlamp systems, an overhead lighting or illumination serves to ensure a minimum luminous intensity (solid angle-related luminous flux of a light source; unit [cd]) above an essentially horizontal cut-off line (or light-dark boundary) of the low beam. FIG. 1 shows an example of an overhead lighting 10, known from the prior art, of a dimmed light distribution 12 with a horizontal cut-off line 14 according to the US standard. The cut-off line 14 of the light distribution 12 has an almost flat, straight extension. It can be clearly seen that the overhead lighting 10 has a very wide extension (from about 25 horizontally to +25 horizontally) and no clearly defined or limited contours. In particular, the brightness at the edges of the overhead lighting 10 fades out slowly over relatively large angular ranges.

[0044] In FIG. 1, various measuring points according to FMVSS No. 108 Low Beam in the version in force on the priority date of the present application are also shown for minimum and/or maximum brightness values in the overhead area. These measuring points include 1U 1.5L-L (corresponding to 1 up and 1.5 to the left all the way to the far left); 0.5U 1.5L-L; 4U 8L; 2U 4L; 1.5U 1R-3R (corresponding to 1.5 up and 1.0 to the right all the way to 3 to the right); 4U 8R; 0.5U 1R-3R and 1.5U 1R-R.

[0045] Overhead lighting 10 ensures that traffic signs and informational signs are sufficiently illuminated despite driving with low beam 12. In current headlamps, this overhead lighting 10 is generated, for example, by prisms or microcylinders on a projection lens of a low beam module (see FIG. 2), a special facet shape in a reflector (not shown) or, more recently, in the case of digital light distributions (see FIG. 3), by brightening points in the projection image of a digital projector, a DMD- or a micro-LED (LED)-module.

[0046] FIG. 2 shows a schematic longitudinal section through a motor vehicle headlamp 20 known from the prior art. This includes a low beam module 22, which is designed here as a projection module or as an ellipsoidal module. The light module 22 is arranged in a housing 24 of the headlamp 20. The housing 24 has a light exit opening 28 in a light exit direction 26, which is closed by a cover pane 30. The light module 22 includes a light source 32 for emitting light. An ellipsoidal or ellipsoid-like reflector 34 is associated with the light source 32, the light source 32 being arranged at a first focus F_1 of the reflector 34. The reflector 34 focuses the incident light from the light source 32 at a second focal point F_2 of the reflector 34. A shade 36 is arranged in the vicinity of the second focal point F_2, with its upper edge lying approximately at the second focal point F_2. Further in direction 26 along an optical axis 38, a projection lens 40 is arranged, which projects the upper edge of the shade 36 onto the road in front of the motor vehicle as a cut-off line of a dimmed light distribution. A prism-shaped or cylinder-shaped deflecting element 44 is arranged or formed on a light exit surface 42 of the lens 40, which deflects part of the light that has passed through the lens 40 into an overhead area above the cut-off line of the dimmed light distribution in order to generate the overhead lighting. In this case, a light entry surface 46 of the lens 40 is designed flat.

[0047] FIG. 3 shows a digital dimmed light distribution 50 known from the prior art. This has an almost flat cut-off line 52 (or light-dark boundary). The digital light distribution 50 is generated, for example, by a digital projector, a DMD- or a LED-module. Bright spots in the projection image are shown on an exemplary basis and designated by reference sign 54.

[0048] In current applications, the overhead lighting or illumination is spatially extended and at the same time not particularly well defined or limited (see FIG. 1). For example, when using the previous prior art in the US Adaptive Driving Beam (ADB) driving test according to FMVSS No. 108 Low Beam, it will produce glare at short distances in front of the motor vehicle and thus prevent an ADB function in compliance with FMVSS No. 108 Low Beam.

[0049] In connection with lighting known in the art, the ADB function cuts a shadow into a (high) beam light distribution in order to shade traffic participants or road users in front and/or oncoming and prevent them from being blinded. However, the shadow in the light distribution also removes the overhead lighting 10 in digital light distributions (see FIG. 3), which means that the desired illumination of traffic signs is missing. Although as a result the glare in the US-ADB driving test is reduced, the required values for minimum luminous intensities at specified measuring points above the cut-off line 52 of the low beam 50 are not achieved, and legal compliance is no longer given.

[0050] The present invention proposes a separate lighting unit 100 (see FIGS. 4 to 7) for use together with a light module 102 of a motor vehicle lighting device 104 (see FIG. 9), wherein the light module 102 is designed to produce a dimmed light distribution 116 (see FIG. 8) with a substantially horizontal cut-off line 118. The lighting device 104 is designed in particular as a headlamp, for example similar to the headlamp 20 in FIG. 2, but without deflection elements 44 on the lens 40. Instead of the projection module 22 in FIG. 2, the lighting device 104 according to the invention can also comprise a reflection module, a digital projector, a DMD-module or a micro-LED-module. In the latter cases, the resulting digital light distribution 116 is composed of thousands of light points arranged in a matrix-like pattern. By deflecting certain light points at which other traffic participants are located into brighter areas of the light distribution 116 or by dimming, shading or switching off certain light points at which other traffic participants are located, sub-areas of a (high beam) light distribution can be shaded in order to prevent blinding of the traffic participants. The other traffic participants are detected using cameras, for example. In the shaded areas, the resulting light distribution 116 forms a shaded (partial) light distribution.

[0051] As shown in FIG. 8, the cut-off line 118 may have a horizontal section 118.2 on the oncoming traffic side (FIG. 8 shows right-hand traffic) and a section 118.1 rising at an angle of 15, for example, on the driver's own side of the road. However, a strictly horizontal course of the entire cut-off line 118 would also be conceivable, i.e., on both the opposite and driver's own side of the road (similar to the cut-off line 52 shown in FIG. 3), or a stepped course with horizontal sections on both sides of the road (oncoming and own traffic side), with the horizontal section on the driver's own side of the road being higher than the horizontal section on the opposite side of the road, where the oncoming traffic is (not shown). Above the cut-off line 118, there is a so-called overhead area 120.

[0052] The lighting unit 100 has a light source 106 that can be switched independently from the light module 102 to generate the dimmed light distribution 116, and an optical assembly 108 assigned to the light source 106. The light source 106 includes, for example, at least one semiconductor light source, in particular at least one LED. In the example of FIGS. 4 to 7, the assembly 108 is shown as a lens system with a lens, of which a light entry surface 110 and a light exit surface 112 can be seen. Of course, the lens system can also comprise more than one lens. Alternatively or additionally, however, the optical assembly 108 could also comprise a reflector and/or a diffusing optical system. The optical assembly 108 is designed to redirect light emitted by the light source 106 of the lighting unit 100 to generate an overhead lighting or illumination 114 that is spatially limited and defined at least in the direction of an oncoming traffic side in the overhead area 120 above the cut-off line 118 of the dimmed light distribution 116.

[0053] The dimmed light distribution 116 in the context of the present invention may be a conventional (static) low beam (see FIG. 8). However, it could also be a digital or ADB beam in which a shadow is cut into the ADB light distribution to prevent glare for or blinding of other traffic participants or road users travelling ahead and/or oncoming (so-called ADB switching situation). The shaded area of the ADB light distribution represents a (zonal or partial) dimmed light distribution 116 in the sense of the present invention, the overhead area 120 of which can also be illuminated by the separate lighting unit 100 according to the invention in the special manner described.

[0054] The fact that the lighting unit 100 is designed separately from the light module 102 and can be activated independently therefrom means that the overhead area 120 can be illuminated even when parts of the light distribution 116 are shaded, e.g., in the case of digital or ADB light distributions.

[0055] In the case of a motor vehicle headlamp 104 designed to produce a digital ADB light distribution or beam pattern, the switchable light source 106 of the lighting unit 100 is turned on at least when a shadow is cut into the ADB beam pattern to prevent glare for or blinding of other traffic participants or road users travelling ahead and/or oncoming (so-called ADB switching situation). However, it would also be conceivable for the switchable light source 106 to be turned on permanently and for the overhead lighting 114 to be permanently generated with the spatially limited defined level of illumination, regardless of whether or not there is an ADB switching situation.

[0056] In contrast to the prior art, the overhead lighting 114 generated by the lighting unit 100 is spatially clearly defined and limited at least towards (or in the direction of) the oncoming traffic side and well controllable. The brightness reduction or drop in the horizontal direction, at least towards the oncoming traffic side, corresponds, for example, to a brightness reduction or drop to 20% of the brightest value within 3 horizontally. For example, overhead lighting 114 has its maximum brightness at measuring point 2U 4L (i.e., at 2 vertically and 4 horizontally) and only 20% of the maximum value, or the overhead lighting 114 has its greatest brightness up to 5 horizontally and only 20% of the maximum value already at 8 horizontally.

[0057] The overhead lighting 114 can be designed symmetrically in respect to a vertical centre plane vv (see FIG. 8), or the overhead lighting 114 is only clearly defined towards the oncoming traffic side and its brightness slowly fades out on its own traffic side, e.g., from +5 to +15 or +20 horizontally (not shown).

[0058] The overhead lighting 114 produces a clearly defined level of illumination in the overhead area 120. This prevents, on the one hand, glare for other road users in the driving test, especially in a US-ADB driving test, and at the same time ensures that the necessary minimum luminous intensities in the shadows are reached. The light emitted by the overhead lighting 114 has a clearly visible (significant) brightness reduction or drop (i.e., a large brightness gradient) between, on the one hand, an area that includes measuring points (e.g.: 2U 4L; 1.5U 1R-3R), where a minimum luminous intensity is required, and on the other hand a glare area, which extends on the oncoming traffic side, for example, approximately between 8 and 20 horizontally. With the help of the lighting unit 100 and the narrowly limited overhead lighting 114 generated by the lighting unit 100, glare at short distances in front of the motor vehicle during the ADB driving test, in particular during the US-ADB driving test according to FMVSS No. 108 Low Beam, can be reduced while at the same time ensuring legal compliance, in particular in accordance with FMVSS No. 108 Low Beam, in co-operation or superimposition with the main lighting (dimmed light distribution 116) generated by the light module 102.

[0059] It is proposed that the optical assembly 108 is designed to illuminate, with the defined level of illumination or the overhead lighting 114, a measuring area in the overhead area 120, where a minimum luminous intensity is required by law or standard applicable in the respective country or region, so that the legal requirements for the minimum luminous intensity in the overhead area 120 of the dimmed light distribution 116 are met. The legal requirements may be specified, for example, in the USA by the FMVSS (Federal Motor Vehicle Safety Standard) No. 108 Low Beam in the version in force/applicable on the priority date of present application or in the EU by the ECE-R 48 regulation.

[0060] In one embodiment, the measuring area illuminated by the lighting unit 100 with the defined level of illumination or the overhead lighting 114 includes the measuring points 2U 4L (2 vertically, 4 horizontally); 1.5U 1R-3R (1.5 vertically, 1 to 3 horizontally) according to FMVSS No. 108 Low Beam. This ensures that the dimmed light distribution 116 fulfils the requirements for minimum luminous intensity in the overhead area 120.

[0061] Furthermore, the optical assembly 108 may be designed to omit with the defined level of illumination or the overhead lighting 114 a glare area on an oncoming traffic side of the light distribution 116, in particular in a range from 8 to 20 horizontally (see FIG. 8). Consequently, the overhead lighting 114 formed by the lighting unit 100 only illuminates the overhead area 120 in a relatively narrowly limited region on both sides of a vertical centre plane (vv) and, in one embodiment, only extends to a maximum of 8 horizontally on the oncoming traffic side. This ensures that no glare is produced by glare light at short distances in front of the motor vehicle in the ADB driving test, in particular in the US-ADB driving test according to FMVSS No. 108 Low Beam.

[0062] Furthermore, it is suggested that the optical assembly 108 is designed to omit measuring points 0.5U 1R to 3R (0.5 vertically, 1 to 3 horizontally) according to FMVSS No. 108 Low Beam with the defined level of illumination or to illuminate them only with low luminous intensity. For the purpose of the invention, a low luminous intensity of the overhead lighting 114 is selected such that the minimum brightness of, for example, 500 cd prescribed in accordance with FMVSS No. 108 Low Beam at these measuring points 0.5U 1R to 3R is achieved to a predominant extent by the dimmed light distribution 116 of the light module 102, which is superimposed with the overhead lighting 114. In various operational modes of the present invention, at least 70%, and alternatively at least 80%, and alternatively at least 90%, or alternatively 100% of the minimum brightness is generated by the dimmed light distribution 116 at these measuring points, so that the overhead lighting 114 only generates 30%, 20%, 10% or 0% of the minimum brightness at these measuring points. The illumination of these measuring points is not relevant for the ADB case and thus does not have to be provided by the lighting unit 100 according to the invention. This can additionally prevent glare during the ADB driving test, in particular during the US-ADB driving test.

[0063] As can be seen in FIG. 9, the additional lighting unit 100 can be rigidly coupled to the light module 102 and can be moved therewith in respect to the housing, such as the housing 24 from FIG. 2, of the motor vehicle lighting device 104. In this way, the lighting unit 100 together with the light module 102 can be brought into a basic position or setting (horizontal and/or vertical) before their intended use. Furthermore, the lighting unit 100 together with the light module 102 can be moved during their intended use as part of a dynamic cornering light, a light range control and/or an ADB function. The lighting unit 100 is always correctly aligned in relation to the light module 102. Consequently, the illuminated overhead area 114 is always correctly positioned in relation to the dimmed light distribution 116.

[0064] However, it would also be conceivable for the lighting unit 100 to be designed separately from the light module 102 and to be adjustable independently therefrom. The lighting unit 100 can be arranged inside the housing, e.g., the housing 24 from FIG. 2, of the lighting device 104 or outside.

[0065] The light module 102 is particularly preferably designed to generate an adaptive driving beam (ADB) which comprises a so-called glare-free high beam, and the light source 106 of the additional lighting unit 100 is designed to be activated at least whenever the light module 102 shades at least part of the overhead area 120 when generating the glare-free high beam. This shaded region may then be illuminated with the overhead lighting 114 by the lighting unit 100.

[0066] The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.