Arrangement of a TIR body

Abstract

The invention relates to an optical device and to a headlighting assembly including an optical device. An optical device includes a body of a transparent material arranged to receive light at at least one light input portion. At least a portion of the light is reflected at an outer surface of the body due to total internal reflection. A non-transparent housing is provided to at least partially cover the body. The body is held within the housing by protrusions arranged to abut against the outer surface.

Claims

1. An optical device comprising: a generally flat body of a transparent material comprising at least one light input portion configured to receive light, and an outer surface configured to reflect at least a portion of the light due to total internal reflection, the outer surface further comprising at least one light output portion configured to emit the reflected light and an upper surface portion and a lower surface portion substantially parallel; and a non-transparent housing at least partially covering the body, the housing comprising: housing walls arranged at a distance from the body, and a plurality of protrusions extending from the housing walls and abutting against the upper surface portion and the lower surface portion of the body to hold the body within the housing.

2. The optical device according to claim 1, wherein the housing comprises at least an upper and a lower housing portion, the body being arranged between the upper and lower housing portions, wherein the protrusions are arranged both at the upper and lower housing portions extending to abut against the body.

3. The optical device according to claim 2, wherein the housing portions are connected by one or more form-fitting elements.

4. The optical device according to claim 1, wherein the housing comprises a housing wall arranged at a distance from the body, the protrusions being arranged between the housing wall and the body.

5. The optical device according to claim 1, wherein the body is clamped between the protrusions abutting against the surface at opposite sides.

6. The optical device according to claim 1, wherein regions of contact between a plurality of the protrusions and the outer surface are at least substantially arranged in two planes.

7. The optical device according to claim 1, wherein at least one lens element is arranged to receive light emitted from the body at an output portion thereof.

8. The optical device according to claim 7, wherein the at least one lens element is provided in an opening of the housing.

9. The optical device according to claim 1, wherein the body comprises one or more of the light input portions, and the housing comprises 2-12 of the protrusions per light input portion.

10. The optical device according to claim 1, wherein the housing comprises at least an upper and a lower housing portion, the body being arranged between the upper and lower housing portions, wherein 1-6 protrusions per light input portion are arranged at the upper housing portion, and 1-6 protrusions per light input portion are arranged at the lower housing portion.

11. The optical device according to claim 1, wherein the protrusions have an at least substantially cylindrical shape.

12. The optical device according to claim 1, wherein the protrusions are provided with a rounded or at least partially tapered head arranged to abut against the outer surface.

13. The optical device according to claim 1, wherein the body is held only by the protrusions without contacting other parts of the housing.

14. A headlighting assembly comprising: at least one light source; a generally flat body of a transparent material comprising at least one light input portion configured to receive light from the at least one light source, and an outer surface configured to reflect at least a portion of the light due to total internal reflection, the outer surface further comprising at least one light output portion configured to emit the reflected light and an upper surface portion and a lower surface portion substantially parallel; and a non-transparent housing at least partially covering the body, the housing comprising: housing walls arranged at a distance from the body, and a plurality of protrusions extending from the housing walls and abutting against the upper surface portion and the lower surface portion of the body to hold the body within the housing.

15. The headlighting assembly according to claim 14, wherein the light source comprises at least one LED element or at least one laser lighting element.

16. The headlighting assembly according to claim 14, wherein the housing comprises at least an upper and a lower housing portion, the body being arranged between the upper and lower housing portions wherein the protrusions are arranged both at the upper and lower housing portions extending to abut against the body.

17. The headlighting assembly according to claim 14, wherein the housing comprises a housing wall arranged at a distance from the body, the protrusions being arranged between the housing wall and the body.

18. The headlighting assembly according to claim 14, wherein the body is clamped between the protrusions abutting against the surface at opposite sides.

19. The headlighting assembly according to claim 14, wherein regions of contact between a plurality of the protrusions and the outer surface are at least substantially arranged in two planes.

20. The headlighting assembly according to claim 14, wherein at least one lens element is arranged to receive light emitted from the body at an output portion thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings,

(2) FIG. 1 shows a perspective view of a headlighting assembly according to an embodiment of the invention;

(3) FIG. 2 shows a top view of the headlighting assembly with an upper housing portion taken off;

(4) FIG. 3 shows a schematical partial view of a light beam reflected within a TIR body in the headlighting assembly according to FIG. 1, FIG. 2;

(5) FIG. 4 shows a perspective exploded view of the headlighting assembly according to FIG. 1, FIG. 2.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) FIG. 1 shows a headlighting assembly 10 in a perspective view. The headlighting assembly comprises a housing 12 comprised of an upper housing portion 12a and a lower housing portion 12b.

(7) A double lens element 14 is provided at a front of the head lighting assembly 10, held by the housing 12.

(8) FIG. 2 shows a top view of the head lighting assembly 10 with the upper housing portion 12a taken off. As shown, a TIR body 16 is arranged within the housing 12. Input collimating portions 22a, 22b of the TIR body 16 protrude through openings of the housing 12 such that light input surfaces 24a, 24b are arranged in front of two LED light sources 18a, 20a provided on circuit boards 20a, 20b.

(9) The TIR body 16 is comprised of two substantially identically shaped elements 16a, 16b arranged side by side. Each of the TIR elements 16a, 16b comprises a collimator portion 22a, 22b including a light input surface 24a, 24b arranged opposite the respective LED light source 18a, 18b. At the opposite end of each TIR element 16a, 16b a light output portion in the shape of a curved light output surface 26a, 26b is arranged.

(10) As schematically shown in FIG. 2, light from the LED light sources 18a, 18b enters each of the TIR elements 16a, 16b of the TIR body 16 through the input surfaces 24a, 24b at the input collimators 22a, 22b. The light is guided internally within the TIR body 16 such that beams are emitted at the light output surfaces 26a, 26b. The emitted beam is projected by the double lens element 14 to form an illumination beam.

(11) FIG. 3 schematically shows how light is conducted within the solid transparent TIR body 16. As schematically shown, light guided within the TIR body 16 is reflected at an upper and lower outer surface 28a, 28b of the TIR body 16 due to total internal reflection.

(12) The shape of the TIR body 16 is also shown in the exploded view of FIG. 4. As described, the TIR body 16 is of generally flat shape with generally plane upper and lower surfaces. The skilled person will understand that the flat shape of the upper and lower surfaces 28a, 28b of the TIR body 16 is shown here to more easily understand the central aspects of the present invention related to mounting of the TIR body 16, while in actual embodiments the shape may differ according to optical considerations, e.g. be provided with raised or lowered portions. Thus, the upper and lower surfaces here referred to as “generally plane” and “generally parallel” may in actual embodiments have a more complex shape to achieve desired optical effects, the specifics of which are outside of the scope of the present invention.

(13) In operation of the LEDs 18a, 18b the TIR body 16 serves to achieve a desired beam shape and intensity distribution for a vehicle front light to be emitted through the lens 14. While the major portion of the light from the LEDs 18a, 18b it is guided within the interior of the TIR body 16 and reflected at its outer surfaces 28a, 28b as schematically shown in FIG. 3, there will generally be certain scattered portions of the light which are emitted from the interior of the TIR body 16, such as schematically indicated by a slash-dotted line in FIG. 3. Such scattered light portions emitted at locations outside of the light output surfaces 26a, 26b are absorbed by the housing 12.

(14) As shown in the figures, the housing 12 comprises housing walls 38a, 38b from which a plurality of protrusions 30 extend into the direction of the TIR body. The protrusions 30 shown in the example are of cylindrical shape with circular cross section. They are formed integrally with the housing 12 to extend substantially perpendicularly from the housing walls 38a, 38b.

(15) As shown in FIG. 3, the protrusions 30 thus establish a distance between the outer surfaces 28a, 28b of the TIR body 16 and the substantially parallel housing walls 38a, 38b. The protrusions 30, as shown in the example, are provided with rounded heads 32.

(16) As shown in the figures, both the upper and lower housing portions 12a, 12b are provided with protrusions 30. The TIR body 16 is thus held by protrusions 30 abutting with their heads 32 against the outer surfaces 28a, 28b from above and below, i.e. from opposing directions. In addition, protrusions 36 are provided projecting from side wall portions of the housing 12 contacting the TIR body 16 from opposing directions to establish a defined position of the TIR body 16. Further protrusions (not shown in FIG. 2) may be provided to abut against the TIR body 16 from different directions, such as front and back, such that it is securely positioned in all axes.

(17) The protrusions are spaced from one another. In the example shown, seven upper and lower protrusions are provided on each housing portion 12a, 12b. The heads 32 of the protrusions 30, 36 are the only points of contact between the housing 12 and the TIR body 16. Thus, the contact surface of housing parts against the outer surfaces 28a, 28b of the TIR body is minimized. Due to the rounded heads 32, each protrusion 30, 36 only leads to a point-shaped contact area. Thus, any influence on the optical properties of the TIR body 16 is minimized. In addition, due to the same number of protrusions provided on both sides, any influence of the optical properties will be at least substantially symmetrical.

(18) The TIR body 16 and the lens 14 are both fixed between the housing portions 12a, 12b. The alignment of the housing portions 12a, 12b on top of each other is achieved by form-fitting elements 34 provided in the corners of the upper and lower housing portions 12a, 12b.

(19) 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 from the scope of the appended claims. For example, the number and shape of the protrusions described above, as well as the shape of the TIR body may differ. In the claims, any reference signs placed 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 a 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.