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(11) | EP 4 180 710 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | ILLUMINATION DEVICE FOR A MOTOR VEHICLE HEADLAMP |
| (57) Illumination device (10) for a motor vehicle headlamp for generating a low beam light
distribution (LB), wherein a vertical extension of the low beam light distribution
extends along a V-V-line from at least 0° down to at least -10° on the V-V-line, said
illumination device (10) comprises at least one light source (50), an optic body (100)
comprising: - a common light input section (110) for coupling light-rays from the at least one light source (50) into the optic body (100), said common light input section (110) having at least one light collecting element (120), which is assigned to a respective light source (50), - a light output section (130) for decoupling light-rays that are coupled into the optic body (100) via the common light input section (110), out of the optic body (100) in a main direction (X) of the illumination device (10), - a projection lens system (200) configured to project the light-rays in front of the illumination device (10), wherein the at least one light collecting element (120) in combination with the optic body (100) allow at least three sets of light-ray paths (LR1, LR2, LR3), wherein the first part of the low beam light distribution (LB1) contributed by light-rays following the first and second light ray paths (LR1, LR2) and the second part of the low beam light distribution (LB2) contributed by light-rays following the third light-ray path (LR3) form the low beam light distribution (LB), wherein the vertical extension of the low beam light distribution (LB) extends along the V-V-line from at least 0° down to at least -10° on the V-V-line. |
[0001] The invention relates to an illumination device for a motor vehicle headlamp for generating a low beam light distribution, wherein a vertical extension of the low beam light distribution extends along a V-V-line from at least 0° down to at least -10° on the V-V-line, said illumination device comprises:
- at least one light source configured to emit light-rays,
- an optic body comprising:
- a common light input section for coupling light-rays from the at least one light source into the optic body, said common light input section having at least one light collecting element, which is assigned to a respective light source and is configured to couple light-rays from the assigned light source into the optic body,
- a light output section for decoupling light-rays that are coupled into the optic body via the common light input section, out of the optic body in a main direction of the illumination device,
- a shell surface limiting the optic body, said shell surface is configured to deflect light-rays coupled into the optic body, which shell surface extends between the common light input section and the light output section,
- a projection lens system, comprising at least one lens, arranged downstream of the optic body along the main direction in order to receive light-rays emitted from the light output section of the optic body, wherein the projection lens system is configured to project the light-rays in front of the illumination device,
[0002] Further, the invention relates to a motor vehicle headlamp comprising at least one illumination device according to the invention.
[0003] In some cases, especially when a high resolution high beam and/or high resolution low beam light distribution is required for a vehicle headlamp, the construction of the corresponding illumination device demands certain requirements that results sometimes in not fulfilling legal requirements on a low beam light distribution (see for example in Official Journal of the EU L 250/92 - 22.08.2014).
[0004] To fulfill also the requirements for the low beam light distribution in view of illumination intensity values and the demanded spatial illumination on a road, an enhanced illumination device is required.
[0006] To achieve this object, the at least one light collecting element in combination with the optic body allow at least three sets of light-ray paths,
wherein the optic body comprises a first set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body via the common light input section along a first light-ray path from the common light input section to the light output section,
wherein the first set of optically operative surfaces comprises a first deflection surface and a light exit surface, wherein the first deflection surface is part of the shell surface and the light exit surface is part of the light output section,
wherein light-rays following the first light-ray path are incident on the first deflection surface and are deflected to the light exit surface for coupling out of the optic body,
and wherein light-rays following a second light-ray path are incident on the light exit surface directly from the common light input section,
wherein light-rays following the first and second light-ray path contribute to generate a first part of the low beam light distribution,
and wherein the optic body comprises a second set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body via the common light input section along a third light-ray path from the common light input section to the light output section,
wherein the second set of optically operative surfaces comprises a second deflection surface and the light exit surface, wherein the second deflection surface is part of the shell surface and separate from the first deflection surface, and wherein the second deflection surface is - in a correct installed state of the illumination device in a vehicle - a top surface of the optic body and is formed as a concave surface,
wherein light-rays following the third light-ray path are incident on the second deflection surface and are deflected to the light exit surface for coupling out of the optic body,
and wherein light-rays following the third light-ray path contribute to generate a second part of the low beam light distribution,
wherein the first part of the low beam light distribution contributed by light-rays following the first and second light ray paths and the second part of the low beam light distribution contributed by light-rays following the third light-ray path form the low beam light distribution, wherein the vertical extension of the low beam light distribution extends along the V-V-line from at least 0° down to at least -10° on the V-V-line.
[0007] Advantageously, the illumination device comprises at least two light sources, wherein the common light input section comprises at least two light collecting elements each assigned to one light source.
[0008] Advantageously, the light sources are arranged in at least one row along a straight horizontal line, wherein the corresponding light collecting elements are arranged in rows along a straight horizontal line, wherein the straight horizontal lines are substantially orthogonal to the main direction.
[0011] Advantageously, the light exit surface and the shell surface intersect in a common surface section line, said common surface section line builds an asymmetric cut-off boundary for the low beam light distribution.
[0012] Advantageously, the projection lens system comprises an optical axis and the light exit surface having a surface vector, which surface vector is inclined to the optical axis of the projection lens system.
[0013] Advantageously, the projection lens system comprises a curved focal surface, preferably a Petzval-surface, wherein the light exit surface is inclined to the curved focal surface, so that only the common surface section line is arranged in the curved focal surface.
[0014] Advantageously, the surface vector of the light exit surface is - seen in a correctly installed state of the illumination device in a vehicle - inclined upward.
[0015] Advantageously, the at least one light collecting element having a curved light input surface for coupling light-rays from the assigned light source into the optic body, wherein the curved light input surface comprises a central section having a convex form.
[0016] Advantageously, the curved light input surface of the at least one light collecting element comprises a first deflection section corresponding to the second deflection surface, wherein the deflection section is configured to deflect light-rays incident on the first deflection section to the second deflection surface.
[0017] Advantageously, the first deflection section has a curvature opposite to the curvature of the central section of the light input surface, preferably a concave curvature.
[0018] Advantageously, the at least one light collecting element comprises a second deflection section corresponding to the first deflection surface, wherein the second deflection section is configured to deflect light-rays incident on second the deflection section to the first deflection surface, wherein light rays following a fourth light ray path, when incident on the second deflection section, and wherein the fourth light ray path contributes to the low beam light distribution.
[0019] Advantageously, the at least one light source emits light-rays in a light emitting direction, wherein the at least one light source is arranged in a way, that the light emit direction is not parallel to the main direction of the illumination device.
[0020] The term "light emitting direction" is to be understood as a direction, in which the at least one light source emits the most or the strongest light as a result of its directionality - or in other words, where the highest light flux is present.
[0021] The object of the invention is also solved by a motor vehicle headlamp comprising at least one illumination device according to the invention.
[0022] The object can also be achieved by a motor vehicle headlamp comprising at least one illumination device according to the invention.
[0023] In the following, in order to further demonstrate the present invention, illustrative and non-restrictive embodiments are discussed, as shown in the drawings, which show:
Fig. 1 an isometric view of an example of an illumination device comprising light sources, an optic body in which light-rays of the light sources can be coupled in, and a projection lens, which is configured to project decoupled light-rays of the optic body in front of the illumination device,
Fig. 2 the optic body of the illumination device of Fig. 1 in a cross-section view, wherein the optic body comprises a light input section and a light output section,
Fig. 3A a detailed view of an example of the light input section of the illumination device of Fig. 1,
Fig. 3B a detailed view of a further example of the light input section of the illumination device of Fig. 1,
Fig. 4 example for a low beam light distribution generated by the illumination device of Fig.1,
Fig. 5 a front view of the light output section of the optic body of the illumination device of Fig. 1, and
Fig. 6 a back view of the light input section of the illumination device of Fig. 1.
[0024] Fig. 1 shows an example of an illumination device 10 for a motor vehicle headlamp for generating a low beam light distribution LB, wherein a vertical extension of the low beam light distribution extends along a V-V-line from at least 0° down to at least -10° on the V-V-line, which can be seen in more detail in Fig. 4.
[0025] The illumination device 10 comprises light sources 50 configured to emit light-rays, an optic body 100 comprising a common light input section 110 for coupling light-rays from the light sources 50 into the optic body 100, wherein the light sources are built as LEDs.
[0026] The common light input section 110 having light collecting elements 120, each of which is assigned to a respective light source 50 and is configured to couple light-rays from the assigned light source 50 into the optic body 100.
[0027] Further, the optic body 100 comprises a light output section 130 for decoupling light-rays that are coupled into the optic body 100 via the common light input section 110, out of the optic body 100 in a main direction X of the illumination device 10.
[0028] The light sources 50 are arranged only in a row along a straight horizontal line, wherein the corresponding light collecting elements 120 are arranged only in a row along a straight horizontal line, wherein the straight horizontal lines are substantially orthogonal to the main direction X, which can be seen for example in Fig. 6, which shows a back view of the optic body 100.
[0029] The optic body 100 also comprises a shell surface 140 limiting the optic body 100 by extending between the common light input section 110 and the light output section 130, said shell surface 140 is configured to deflect light-rays coupled into the optic body 100, preferably by total inner reflection.
[0030] The illumination device 10 comprises further a projection lens system 200, comprising at least one lens (in the shown example exactly one lens), arranged downstream of the optic body 100 along the main direction X in order to receive light-rays emitted from the light output section 130 of the optic body 100, wherein the projection lens system 200 is configured to project the light-rays in front of the illumination device 10, wherein the projection lens system 200 in combination with the light sources 50 and the optic body 100 are configured to generate the low beam light distribution LB illuminated by the projections lens system 200.
[0031] As can be seen in Fig. 2, the light collecting elements 120 in combination with the optic body 100 allow four sets of light-ray paths LR1, LR2, LR3, LR4, wherein the optic body 100 comprises a first set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body 100 via the common light input section 110 along a first light-ray path LR1 from the common light input section 110 to the light output section 130.
[0032] The first set of optically operative surfaces comprises a first deflection surface 310 and a light exit surface 300, wherein the first deflection surface 310 is part of the shell surface 140 and the light exit surface 300 is part of the light output section 130.
[0033] Light-rays following the first light-ray path LR1 are incident on the first deflection surface 310 and are deflected to the light exit surface 300 for coupling out of the optic body 100, wherein light-rays following a second light-ray path LR2 are incident on the light exit surface 300 directly from the common light input section 110, wherein light-rays following the first, second and fourth light-ray path LR1, LR2, LR4 contribute to generate a first part of the low beam light distribution, which first part of the low beam light distribution LB1 can be seen in Fig. 4.
[0034] The optic body 100 comprises a second set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body 100 via the common light input section 110 along a third light-ray path LR3 from the common light input section 110 to the light output section 130.
[0035] The second set of optically operative surfaces comprises a second deflection surface 320 and the light exit surface 300, wherein the second deflection surface 320 is part of the shell surface 140 and separate from the first deflection surface 310, and wherein the second deflection surface 320 is - in a correct installed state of the illumination device 10 in a vehicle - a top surface of the optic body 100 and is formed as a concave surface.
[0036] Light-rays following the third light-ray path LR3 are incident on the second deflection surface 320 and are deflected to the light exit surface 300 for coupling out of the optic body 100, and wherein light-rays following the third light-ray path LR3 contribute to generate a second part of the low beam light distribution LB2, which can also be seen in Fig. 4.
[0037] The first part of the low beam light distribution contributed by light-rays following the first and second light ray paths LR1, LR2 and the second part of the low beam light distribution contributed by light-rays following the third light-ray path LR3 form the low beam light distribution, wherein the vertical extension of the low beam light distribution extends along the V-V-line from at least 0° down to at least -10° on the V-V-line, which can be seen in Fig. 4.
[0038] Further, the light collecting elements 120 having a curved light input surface for coupling light-rays from the assigned light source 50 into the optic body 100, wherein the curved light input surface comprises a central section 122 having a convex form, which can be seen in Fig. 3A, as well as in Fig. 3B, wherein both figures show different embodiments of the illumination device 10 or the optic body 100.
[0039] The curved light input surface of the light collecting elements 120 shown in Fig. 3B comprises a first deflection section 121 corresponding to the second deflection surface 320 of the optic body 100, wherein the deflection section 121 is configured to deflect light-rays incident on the first deflection section 121 to the second deflection surface 320, wherein the light rays following a third light ray path LR3, when incident on the deflection section 121, and wherein the third light ray path LR3 contributes to the low beam light distribution.
first deflection section 121 has a curvature opposite to the curvature of the central section 122 of the light input surface, preferably a concave curvature.
[0040] The light collecting elements 120 in Fig. 3B and also in the shown embodiment in Fig. 2 comprises a second deflection section 123 corresponding to the first deflection surface 310 of the optic body 100, wherein the second deflection section 123 is configured to deflect light-rays incident on second the deflection section 123 to the first deflection surface 310, wherein light rays following a fourth light ray path LR4, when incident on the second deflection section 123, and wherein the fourth light ray path LR4 contributes to the first part of the low beam light distribution LB1.
[0041] Further, the light sources 50 emits light-rays in a light emitting direction X1, wherein the at least one light source 50 shown in the embodiment in Fig. 2 and Fig. 3A, is arranged in a way, that the light emitting direction X1 is not parallel to the main direction X of the illumination device 10. In contrast, in the embodiment shown in Fig. 3A, the light emitting direction X1 is parallel to the main direction X, wherein the light collecting element 120 shown in Fig. 3A is built as TIR-lens, wherein the light collecting element 120 shown in Fig. 3B can be seen as modified TIR-lens.
[0042] Back to Fig. 2, the light exit surface 300 and the shell surface 140 of the optic body 100 intersect in a common surface section line 150, said common surface section line 150 builds an asymmetric cut-off boundary for the low beam light distribution. The common surface section line 150 can be seen in Fig. 5, which shows the optic body 100 in a front view. As can be clearly seen, the common surface section line 150 is configured to generate an asymmetric cut-off boundary in the low beam light distribution.
[0043] Further, the projection lens system 200 comprises an optical axis A and the light exit surface 300 having a virtual surface vector V, which surface vector V is inclined to the optical axis A of the projection lens system 200, wherein the surface vector V of the light exit surface 300 is - seen in a correctly installed state of the illumination device 10 in a vehicle and shown in Fig. 2 - inclined upward, so that the light exit surface 300 is facing in an upward direction.
[0044] Moreover, the projection lens system 200 comprises a curved focal surface F, preferably a Petzval-surface, wherein the light exit surface 300 is inclined to the curved focal surface F, so that only the common surface section line 150 is arranged in the curved focal surface F.
| Illumination device | 10 |
| Light source | 50 |
| Optic body | 100 |
| Common light input section | 110 |
| Light collecting element | 120 |
| First deflection section | 121 |
| Central section | 122 |
| Second deflection section | 123 |
| Light output section | 130 |
| Shell surface | 140 |
| Common surface section line | 150 |
| Projection lens system | 200 |
| Light exit surface | 300 |
| First deflection surface | 310 |
| Second deflection surface | 320 |
| Optical axis | A |
| Curved focal surface | F |
| Light distribution | LB |
| First part of light distribution | LB1 |
| Second part of light distribution | LB2 |
| Set of light-ray path | LR1, LR2, LR3, LR4 |
| Surface vector | V |
| Main direction | X |
| Light emitting direction | X1 |
- at least one light source (50) configured to emit light-rays,
- an optic body (100) comprising:
- a common light input section (110) for coupling light-rays from the at least one light source (50) into the optic body (100), said common light input section (110) having at least one light collecting element (120), which is assigned to a respective light source (50) and is configured to couple light-rays from the assigned light source (50) into the optic body (100),
- a light output section (130) for decoupling light-rays that are coupled into the optic body (100) via the common light input section (110), out of the optic body (100) in a main direction (X) of the illumination device (10),
- a shell surface (140) limiting the optic body (100) by extending between the common light input section (110) and the light output section (130), said shell surface (140) is configured to deflect light-rays coupled into the optic body (100),
- a projection lens system (200), comprising at least one lens, arranged downstream of the optic body (100) along the main direction (X) in order to receive light-rays emitted from the light output section (130) of the optic body (100), wherein the projection lens system (200) is configured to project the light-rays in front of the illumination device (10),
wherein the projection lens system (200) in combination with the at least one light source (50) and the optic body (100) are configured to generate the low beam light distribution (LB) illuminated by the projections lens system (200),characterized in that
the at least one light collecting element (120) in combination with the optic body (100) allow at least three sets of light-ray paths (LR1, LR2, LR3),
wherein the optic body (100) comprises a first set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body (100) via the common light input section (110) along a first light-ray path (LR1) from the common light input section (110) to the light output section (130),
wherein the first set of optically operative surfaces comprises a first deflection surface (310) and a light exit surface (300), wherein the first deflection surface (310) is part of the shell surface (140) and the light exit surface (300) is part of the light output section (130),
wherein light-rays following the first light-ray path (LR1) are incident on the first deflection surface (310) and are deflected to the light exit surface (300) for coupling out of the optic body (100),
and wherein light-rays following a second light-ray path (LR2) are incident on the light exit surface (300) directly from the common light input section (110),
wherein light-rays following the first and second light-ray path (LR1, LR2) contribute to generate a first part of the low beam light distribution (LB1),
and wherein the optic body (100) comprises a second set of optically operative surfaces for guiding at least part of the light-rays coupled into the optic body (100) via the common light input section (110) along a third light-ray path (LR3) from the common light input section (110) to the light output section (130),
wherein the second set of optically operative surfaces comprises a second deflection surface (320) and the light exit surface (300), wherein the second deflection surface (320) is part of the shell surface (140) and separate from the first deflection surface (310), and wherein the second deflection surface (320) is - in a correct installed state of the illumination device (10) in a vehicle - a top surface of the optic body (100) and is formed as a concave surface,
wherein light-rays following the third light-ray path (LR3) are incident on the second deflection surface (320) and are deflected to the light exit surface (300) for coupling out of the optic body (100),
and wherein light-rays following the third light-ray path (LR3) contribute to generate a second part of the low beam light distribution (LB2),
wherein the first part of the low beam light distribution (LB1) contributed by light-rays following the first and second light ray paths (LR1, LR2) and the second part of the low beam light distribution (LB2) contributed by light-rays following the third light-ray path (LR3) form the low beam light distribution, wherein the vertical extension of the low beam light distribution (LB) extends along the V-V-line from at least 0° down to at least -10° on the V-V-line.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Non-patent literature cited in the description
- Official Journal of the EU, 2014, vol. L 250, 92- [0003]