LIGHTING ARRANGEMENT

Abstract

The invention relates to a lighting arrangement, in particular a lighting arrangement which may be used in a headlamp of a vehicle. A beam shaping arrangement comprises a light input portion for receiving light emitted from a light source and a light output portion for emitting a shaped beam. The light output portion is spaced from the light input portion in a forward direction. In order to achieve a desired illumination beam pattern suited for a vehicle headlamp the beam shaping arrangement is disposed to divide light from the light input portion into at least a first and a second beam portion separated in height direction. The first and second beam portions are led to converge in the height direction towards the light output portion. At the light output portion, the second beam portion is directed at a peripheral portion arranged laterally further outward relative to the first beam portion.

Claims

1. A Lighting arrangement including a light source, and at least one beam shaping arrangement including a light input portion for receiving light emitted from the light source, a light output portion for emitting a shaped beam, the light output portion being spaced from the light input portion and comprising a central output portion and a peripheral output portion, the peripheral output portion being laterally outward relative to the central output portion, and a transparent body including reflection surfaces at which light may be reflected due to total internal reflection, wherein a forward direction is defined from the light input portion into the direction of the light output portion, with the forward direction arranged substantially horizontally, wherein the beam shaping arrangement is disposed such that light from the input portion is divided into at least a first and a second beam portion separated in a height direction relative to the forward direction, the first beam portion is a center beam, which is directed to the central portion of the light output portion, the second beam portion is a peripheral beam, which is relative to the first beam portion directed further outward to the peripheral portion of the light output portion, and the first and second beam portions are led to converge in the height direction towards the light output portion.

2. The lighting arrangement according to claim 1, wherein the transparent body includes at least one central cavity.

3. The lighting arrangement according to claim 2, wherein the peripheral portion is arranged at a first lateral side of the central output portion, and the beam shaping arrangement is disposed such that one or more further beam portions are directed to further peripheral portions of the light output portion arranged at a second lateral side of the central output portion, the second lateral side being arranged opposite of the first lateral side.

4. The lighting arrangement according to claim 1, wherein the beam shaping arrangement is disposed such that the first beam portion is a first peripheral beam, which is directed to a first peripheral portion of the light output portion, and the second beam portion is a second peripheral beam, which is directed to a second peripheral portion of the light output portion, the said second peripheral portion being arranged laterally further outward relative to the first peripheral portion.

5. The lighting arrangement according to claim 4, wherein the first peripheral portion and second peripheral portions are arranged at a first lateral side of the central output portion of the light output portion, and the beam shaping arrangement is disposed such that further beam portions are directed to peripheral portions arranged at a second lateral side of the central output portion, the second lateral side being arranged opposite of the first lateral side.

6. The lighting arrangement according to claim 1, wherein the beam shaping arrangement is disposed to divide light from the light input portion into at least the first beam portion, the second beam portion, and a third beam portion, the first, second and third beam portions being separated in a height direction, the beam shaping arrangement being disposed such that the first beam portion is a center beam, which is directed to the central output portion of the slight output portion, and the second beam portion is a first peripheral beam, which is directed to a first peripheral portion of the light output portion, and the third beam portion is a second peripheral beam, which is directed to a second peripheral portion of the light output portion, the second peripheral portion being arranged laterally further outward relative to the first peripheral portion.

7. The lighting arrangement according to claim 6, wherein the first and second peripheral portions are arranged on a first lateral side of the centeral output portion, and the beam shaping arrangement is disposed such that one or more further beam portions are directed to peripheral portions arranged at a second lateral side of the central output portion, the second lateral side being arranged opposite to the first lateral side.

8. The lighting arrangement according to claim 6, wherein the beam shaping arrangement includes at least one lateral reflection surface to reflect at least one of the beam portions into a lateral direction.

9. The lighting arrangement according to claim 8, wherein the beam shaping arrangement includes at least a first and a second lateral reflection surface, the first lateral reflection surface disposed to reflect at least one of the beam portions into a lateral direction towards the second lateral reflection surface, and the second lateral reflection surface disposed to direct the beam portion into a direction at least substantially parallel to the forward direction towards the light output portion.

10. The lighting arrangement according to claim 6, wherein the beam shaping arrangement is disposed such that at least one of the beam portions is led to diverge from the forward direction in the height direction and then led to converge towards the forward direction in thud height direction.

11. The lighting arrangement according to claim 10, wherein the beam shaping arrangement includes a bridge member extending from the light input portion to the light output portion.

12. The lighting arrangement according to claim 1, wherein the beam shaping arrangement is disposed such that both the first and second beam portions are directed to be at least substantially parallel to the forward direction at the light output portion.

13. The lighting arrangement according to claim 1, wherein the beam shaping arrangement has an extension in lateral direction which is more than twice an extension in the height direction.

14-15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows a partly schematical top view of an embodiment of a lighting arrangement including first embodiment of a TIR body;

[0030] FIG. 2 shows a side view of the lighting arrangement of FIG. 1;

[0031] FIGS. 3-7 show a second embodiment of a TIR body in a perspective view, front view, top view, back view and side view;

[0032] FIGS. 8, 9 show the TIR body from FIG. 3-7 in a top and side view with beam paths;

[0033] FIG. 10 shows a perspective view of a third embodiment of a TIR body;

[0034] FIGS. 10a, 10b, 10c show sectional views of the TIR body of FIG. 10, the planes A, B and C in FIG. 10 showing the position of the sections

[0035] FIG. 11 shows a front view of the TIR body of FIG. 10.

DETAILED DESCRIPTION OF EMBODIMENTS

[0036] FIG. 1, 2 schematically show a lighting arrangement 10 in a top view and side view. The lighting arrangement includes an LED light source 12, a beam shaping arrangement which in the present example is constituted by a solid body 10 made out of transparent material acting as a TIR (total internal reflection) body, and a projection lens 16.

[0037] The lighting arrangement may be, for example, part of a headlamp of a motor vehicle.

[0038] Light emitted from the light emitting surface of the LED light source 12 enters the interior of the TIR body 14 at a light input surface 20 and is internally conducted and guided within the TIR body 14 to be emitted at a light output surface 22 thereof. As will be further explained below, the light intensity distribution emitted from the light emitting surface of the LED 12 as a Lambertian emitter is altered within the TIR body 14 such that a shaped illumination beam 24 is emitted at the light output surface 22 to be projected by the projection lens 16.

[0039] While the input beam of light received at the light input surface 20 of the TIR body 14 corresponds to the square shape of the light emitting surface of the LED 12, the shaped beam 24 is laterally widened, i.e. extended into lateral left and right directions as indicated L and R in FIG. 1. The height direction H is indicated in FIG. 2 for reference.

[0040] In the schematical example of FIG. 1, FIG. 2, a forward direction of the beam shaping arrangement may be defined by an optical axis 18 through the center of the LED 12, the center of the light input surface 20, the center of the light output surface 22 and the center of the projection lens 16. For more detailed embodiments, such as shown in FIG. 3-11, these elements may not be exactly aligned, such that an optical axis may not be easily defined for the whole arrangement. However, a forward direction may still be defined through the center of the light input surface 20 and the light output surface 22, e.g. as shown in FIG. 10a.

[0041] The TIR body 14, as shown in FIG. 1, FIG. 2, is formed in one piece. Three portions arranged one behind the other in the forward direction may be identified, namely an input collimator portion 26, a beam spreading portion 28 with a central cavity 30, and a lens adaptation portion 32. A separation of the three portions 26, 28, 32 is schematically designated in FIG. 1, FIG. 2 by vertical lines.

[0042] Exterior surfaces of the TIR body 14 can serve as reflection surfaces for light guided within the TIR body 14 if struck by light at an angle below the angle of total reflection. Using this effect, the TIR body 14 is shaped to achieve the desired shaped beam 24.

[0043] The collimator portion 26 is shaped as a cut-off pyramid with substantially square base. The light input surface 20 is square and corresponds to the size of the light emitting surface of the LED 12. From the light input surface 20, the input collimator portion 26 widens both laterally and vertically in the forward direction.

[0044] The lens adaptation portion 32 comprises the light output surface 22. In order to adapt to the lens 16, the light output surface 22 has concave shape.

[0045] The beam spreading portion 28 comprises left and right wing portions 50a, 50b to both lateral sides of the central cavity 30 and an arch shaped bridge portion 38 extending over the cavity 30.

[0046] The input beam of light at the light input surface 20 is divided into a center beam 34, shown in FIG. 1, FIG. 2 in dashed lines, and left and right peripheral beams 36, shown in dotted lines.

[0047] FIG. 2 shows how the center beam 34 and the peripheral beams 36 are separated within the TIR body 14 in the height direction H. Light portions emitted upward form the central beam 34, whereas light portions emitted substantially horizontally or downward form the peripheral beams 36.

[0048] The center beam 34 is conducted within the bridge portion 38 arranged parallel to the optical axis 18 in the center of the beam spreading portion 28 of the TIR body 14. The bridge portion 38 is an arch shaped light guide for guiding the center beam 34 from the input collimator portion 26 to a center portion 46 of the light output surface 22 at the lens adaptation portion 32.

[0049] Left and right peripheral beams 36 are guided, as shown in FIG. 2, within the beam spreading portion 28 of the TIR body 14 below the bridge portion 38. The cavity 30 is formed like a wedge, its front edge being arranged on the optical axis 18 and two front surfaces 40a, 40b extending laterally from the front edge under an oblique angle to the optical axis 18. The front surfaces 40a, 40b reflect the peripheral beam 36 due to total internal reflection. The peripheral beam 36 is separated at the front edge of the cavity 30 into left and right peripheral beams reflected to both lateral sides.

[0050] Both peripheral beams 36 are again reflected at outer surfaces 42a, 42b, of the wing portions 50a, 50b. The surfaces 42a, 42b are also arranged at an oblique angle to the optical axis 18 such that, as shown in FIG. 1, the peripheral beams 36 at the light output surface 22 are directed substantially parallel to the optical axis, but pass through laterally peripheral portions 44a, 44b of the light output surface 22.

[0051] The resulting shaped beam 24 emitted at the light output surface 22 is thus composed of the center beam 34 emitted at the center portion 46 of the light output surface 22 and the peripheral beams 36 emitted at the laterally peripheral portions 44a, 44b thereof.

[0052] The resulting shaped beam 24 is thus laterally spread out over the width of the light output surface 22, thus substantially wider, in the example more than 15 times, compared to the square light emitting surface of the LED 12. In the height direction H, the resulting shaped beam 24 has roughly the same or only slightly larger extension compared to the LED 12.

[0053] FIG. 3 shows a second embodiment of a TIR body 100 in a perspective view. Other views of the TIR body 100 are shown in FIGS. 4-7. The TIR body 100 generally corresponds to the TIR body 10 according to the first embodiment. Similar or comparable parts thereof will be designated by like reference numerals.

[0054] The TIR body 100 comprises an input collimator portion 26 with a square light input surface 20, and a beam spreading portion 28 with wing portions 50a, 50b extending to both lateral sides of the forward direction 18. The beam spreading portion 28 includes a central cavity 30. A bridge portion 38 is arranged above the central cavity 30. In the example shown in FIGS. 3-7, the TIR body 100 does not have a specially shaped lens adaptation portion with concave shape. The beam spreading portion 28 terminates in a plane light output surface 22.

[0055] The beam spreading portion 28 includes, arranged on top of the wing portions 50a, 50b, right and left top wing portions 52a, 52b.

[0056] The TIR body 100 is designed in the same way as the TIR body 10 according to the first embodiment to receive light from an LED light source 12 at the light input surface 20 and shape a laterally spread output beam 24 thereof by separating beam portions in height direction and guiding them towards different portions of the light output surface 22.

[0057] Exemplary beam paths are shown in FIG. 8, FIG. 9, including first left peripheral beam 35 shown as dotted lines (symmetrical first right peripheral beam not shown for clarity), second right peripheral beam 36 shown as slash-double-dotted lines (symmetrical second left peripheral beam not shown for clarity), and a central beam 34 shown as a dashed line.

[0058] As shown in FIG. 9, the central beam 34 and the first and second peripheral beams 35, 36 follow different beams paths within the TIR body 100 separated in the height direction. Light emitted from the light input surface 20 into upper directions forms the central beam 34 centrally guided along the bridge member 38 to the central portion 46 of the light output surface 22. Light emitted substantially horizontally forms the left and right first peripheral beams 35, whereas light emitted into lower directions forms the left and right second peripheral beams 36.

[0059] The peripheral beams 35, 36 are guided within the beam spreading portion 28 of the TIR body 100 as shown in FIG. 8. As in the previously discussed example, the shape of the beam spreading portion 28 is laterally symmetrical, so that the peripheral beams 35, 36 will divide at the front edge of the cavity 30 into left and right beam portions. In order to better illustrate the beam paths, FIG. 8 shows only the left portion of the first peripheral beam 35 and the right portion of the second peripheral beam 36.

[0060] The first peripheral beam 35 is divided at the front edge of the cavity 30 to be reflected at the reflective surfaces 40a, 40b into left and right lateral directions. The thus reflected light of the left and right first peripheral beams 35 is then again reflected at outside surfaces 54a, 54b of the top wing portions 52a, 52b of the beam spreading portion 28. After the second reflection, the first peripheral beams 35 are again substantially parallel to the forward direction 18 and emitted through inner peripheral portions 44 of the light output surface 22. The inner peripheral portions 44 directly border the central portion 46, such that the shaped beam 24 is emitted through the light output surface 22 continuously in the lateral directions.

[0061] As shown in FIG. 9, the second peripheral beams 36 are guided within a lower portion of the TIR body 100, such that in the height direction H the first peripheral beams 35 are arranged between the center beam 34 and the second peripheral beams 36.

[0062] The second peripheral beam portions 36 are also reflected twice, first at the front surfaces 40a, 40b of the cavity 30 and subsequently at side surfaces 42a, 42b of the wing portions 50a, 50b. A thus reflected beam 36 is directed substantially parallel to the forward direction 18 and emitted through outer peripheral portions 45 of the light output surface 22.

[0063] The outer peripheral portions 45 are arranged laterally further outward relative to the forward direction 18, such that the inner peripheral portions 44 are arranged laterally in between the center portion 46 and the outer peripheral portions 45.

[0064] The light emitted from the LED 12 is spread out broadly in both lateral directions. The spread beam 24 is composed of contributions from the central beam 34 emitted at the center portion 46, the left and right first peripheral beams 35 emitted at inner peripheral portions 44 of the light emitting surface 22, and the left and right second peripheral beams 36 emitted at outer peripheral portions 45. The TIR body 100 is shaped such that all of the light output surface 22 is illuminated, i.e. the shaped beam 24 is continuous in the lateral direction.

[0065] As explained, the spread of the beam 24 as compared to the light emitting surface of the LED 12 is achieved by separating different beam portions in the input collimator 26 by their height direction, i.e. by their angle of inclination relative to the forward direction 18 and guiding the respective beam portions 34, 35, 36 along the described beam paths towards the light output surface 22. As shown in FIG. 9, the different beam portions 34, 35, 36 converge again in the height direction H towards the light output surface 22. Thus, the output beam 24 may have the same height dimension as the light output surface of the LED 12, or may be only slightly larger in the height direction H.

[0066] FIG. 10 shows a third embodiment of the TIR body 110. The TIR body 110 corresponds in shape to two of the TIR bodies 100 described above arranged side by side. Similar or comparable parts will be designated by like reference numerals.

[0067] Each of the halves of TIR body 110 comprises an input collimator 26 and beam spreading portions 28 with wing portions 50a, 50b, top wing portions 52a, 52b, and bridge portions 38. Light output surfaces 22 are formed at concave lens adaptation portions 32.

[0068] The TIR body 110 may be used in a vehicle headlamp with two separate LED light sources arranged in front of the light input surfaces 20. Two separate lenses, or a double lens, may be arranged in front of the light output surfaces 22.

[0069] FIG. 10a shows a longitudinal sectional view of the sectional plane corresponding to the plane A in FIG. 10. The relative arrangement of the input collimator 26, the cavity 30 with one front surface 40a and the bridge member 38 above are shown. As further visible, the lens adaptation portion 32 widens in height direction H towards the output surface 22.

[0070] FIG. 10b, 10c show sectional view of the sectional planes B, C in FIG. 10, showing the shape of the wing portions 50a, 50b and top wing portions 52a, 52b.

[0071] The light output surface 22 of the TIR body 110 is shown in the front view of FIG. 11. It is bordered by upper and lower front edges 56, 58 extending laterally. The lower edge 58 is projected by a projection lens to achieve an illumination beam with a light/dark boundary. In order to conform to regulations, the lower edge 58 has a particular asymmetrical shape to achieve a light/dark boundary with a horizontal portion and an inclined portion. At the center of the light output surface 22, the lower edge 58 comprises an inclined edge portion 58b adjacent to a substantially horizontal edge portion 58a. In the projected beam, this causes the desired horizontal/inclined light/dark boundary.

[0072] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing form the scope of the dependent claims.

[0073] For example, applying the above described concept of first separating beam portions by height or direction of inclination, and then directing the corresponding beam portions to different lateral portions of a light output surface, a skilled person will be able to propose many different shapes of a TIR body. In particular, the relative dimensions of the light input and light output surface of the TIR body may differ. For example, the height of the light output surface of the TIR body may be even less than the height of the light input surface.

[0074] While the described embodiments show symmetrical arrangements, it is also possible to provide laterally non-symmetrical lighting arrangements. The input beam may be divided in the height direction into two, three, or more different beam portions.

[0075] While the above embodiments rely on a TIR body, the same concept may also be realized by correspondingly arranged reflector surfaces, such that the beam portions travel through air rather than in the interior of a TIR body.

[0076] In the claims, any reference signs place between parentheses shall not be construed as limiting the claim. The word comprising does not exclude the presence of elements or steps other than those listed in the claim. The word a or an preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.