Headlight with Anti-Condensation Protection Device

Abstract

The invention relates to a headlight (1), comprising a headlight housing (10) with a light exit opening (12), which is closed by means of a cover plate (11), at least one LED light source (21), which is arranged in at least one light module (20) positioned in the headlight housing (10) for generating a specified light distribution in front of the headlight (1), as well as a condensation protection device (30) with at least one air duct (40) for guiding air (41), as well as with at least one radiation emitter (60), wherein the at least one air duct (40) has an air entry opening (42) and at least one air exit opening (43), and the air exit opening (43) preferably faces the cover plate (11), as well as the air (41) guided in the air duct (40) can be heated up by means of the thermal radiation generated by the radiation emitter (60). The at least one radiation emitter (60) is arranged within the air duct (40) in the region of the air entry opening (42), wherein the air duct (40) is made of an infrared radiation-reflecting as well as light-impermeable wall material (45), and the air duct (40) has at least one curved longitudinal axial section (50) with a radius of curvature (51) and an angle of curvature (52) between the air entry opening (42) and the air exit opening (43).

Claims

1. A headlight (1), in particular a motor vehicle headlight, comprising: a headlight housing (10) with a light exit opening (12), which is closed by means of a cover plate (11); at least one LED light source (21), which is arranged in at least one light module (20) positioned in the headlight housing (10) for generating a specified light distribution in front of the headlight (1); a condensation protection device (30) arranged in the headlight housing (10) with at least one air duct (40) for guiding air (41); and at least one radiation emitter (60), wherein the at least one air duct (40) has an air entry opening (42) and at least one air exit opening (43), and the at least one air exit opening (43) faces the cover plate (11), wherein the air (41) guided in the at least one air duct (40) can be heated by thermal radiation generated by the at least one radiation emitter (60), wherein the at least one radiation emitter (60) is arranged within the at least one air duct (40) in the region of the air entry opening (42), wherein the air duct (40) is made of an infrared radiation-reflecting and light-impermeable wall material (45), and the at least one air duct (40) has at least one curved longitudinal axial section (50) with a radius of curvature (51) and an angle of curvature (52) between the air entry opening (42) and the at least one air exit opening (43).

2. The headlight (1) according to claim 1, wherein the at least one air duct (40) between the air entry opening (42) and the at least one air exit opening (43) has a first curved longitudinal axial section (50) as well as, spaced apart therefrom in the longitudinal axial direction (44) of the air duct (40), at least one further, second curved longitudinal axial section (55).

3. The headlight (1) according to claim 2, wherein the radii of curvature (51, 56) and the angles of curvature (52, 57) of the first curved longitudinal axial section (50) and of the at least one further, second curved longitudinal axial section (55) are identical in each case.

4. The headlight (1) according to claim 2, wherein the radii of curvature (51, 56) and/or the angles of curvature (52, 57) of the first curved longitudinal axial section (50) and of the at least second curved longitudinal axial section (55) are different.

5. The headlight (1) according to claim 1, wherein the angle of curvature (52, 57) of the at least one curved longitudinal axial section (50, 55) of the air duct (40) is between 50° and 130°.

6. The headlight (1) according to claim 1, wherein the radius of curvature (51, 56) of the at least one curved longitudinal axial section (50, 55) of the air duct (40) is from 0 mm to 100 mm.

7. The headlight (1) according to claim 1, wherein the air duct (40) is made of a wall material (45), which is selected from sheet steel, aluminum, aluminum alloys, metal matrix composite material, plastic, temperature-resistant plastic, or plastic composite material.

8. The headlight (1) according to claim 1, wherein the radiation emitter (60) is an infrared radiator (61).

9. The headlight (1) according to claim 1, wherein the radiation emitter (60) is a halogen light source (65).

10. The headlight (1) according to claim 1, wherein the air duct (40) is equipped on its inner surfaces (46) with a visible light-absorbing, light-shielding coating (70).

11. The headlight (1) according to claim 1, wherein the corrosion protection device (30) furthermore comprises a fan blower (80), which fan blower (80) is connected to the air duct (40).

12. The headlight (1) according to claim 11, wherein the fan blower (80) is integrated in the air duct (40).

13. The headlight (1) according to claim 1, wherein the air exit opening (43) of the air duct (40) is formed as diffusor (75) for the even air distribution.

14. A motor vehicle with at least one headlight (1) according to claim 1.

15. The headlight according to claim 5, wherein the angle of curvature (52, 57) of the at least one curved longitudinal axial section (50, 55) of the air duct (40) is between 60° and 120°.

16. The headlight according to claim 5, wherein the angle of curvature (52, 57) of the at least one curved longitudinal axial section (50, 55) of the air duct (40) is between 70° and 110°.

17. The headlight (1) according to claim 6, wherein the radius of curvature (51, 56) of the at least one curved longitudinal axial section (50, 55) of the air duct (40) is from 1 mm to 80 mm.

18. The headlight (1) according to claim 1, wherein the radiation emitter (60) is a quartz radiator, a halogen radiator, or an infrared lamp.

19. The headlight (1) according to claim 10, wherein the light-shielding coating (70) is jet-black or another dark color.

Description

[0039] Further details, features, and advantages of the invention follow from the following description of exemplary embodiments, which are illustrated schematically in the drawings, in which:

[0040] FIG. 1 shows a headlight according to the invention with a condensation protection device in a partially exposed oblique view from the front;

[0041] FIG. 2 shows possible versions of air ducts with a curved (FIG. 2a) or bent (FIG. 2b) longitudinal axial section in schematic drawings;

[0042] FIG. 3 shows a further embodiment according to the invention of a headlight in an exposed side view with a condensation protection device with a twice-bent air duct in installation position within a headlight housing;

[0043] FIG. 4 shows a next embodiment according to the invention of a headlight in an exposed side view with a condensation protection device with a twice-curved air duct in the installation position within a headlight housing;

[0044] FIG. 5 shows a further embodiment according to the invention of a headlight in an exposed side with a forked, in each case twice-curved air duct of a condensation protection device in the installation position within the headlight housing;

[0045] FIG. 6 shows possible versions of air ducts with a curved (FIG. 6a) or bent (FIG. 6b) longitudinal axial section in schematic drawings, wherein the air exit opening is in each case formed in the form of a diffusor.

[0046] FIG. 1 shows a first headlight 1 according to the invention with a condensation protection device 30. This is a headlight 1 for a motor vehicle. The headlight 1 has a headlight housing 10 together with a cover plate 11, which, in a manner known per se, closes a light exit opening 12, which, in the installation position of the headlight 1 in the motor vehicle, faces forward in the driving direction in the direction of a roadway. A light module 20 with several LED light sources 21 is located in the interior of the headlight housing 10 here. The headlight 1 is equipped with a condensation protection device 30, which has an air duct 40 for guiding air 41. The air flow direction within the air duct 40 is symbolized by means of an arrow 41 here. The air duct 40 shown here is inclined essentially perpendicularly or slightly obliquely upwards, respectively, is fastened within the headlight housing 10, and has an air entry opening 42 on its lower end in the installation position, as well as an air exit opening 43 on its upper, curved end. The longitudinal axial direction of the straight length section of the air duct 40 is identified with reference numeral 44 in order to characterize the longitudinal axis of the air duct 10. The air duct 10 is made of a wall material 45 here, for example of a temperature-resistant plastic of polybutylene terephthalate (in short: PBT). An inner surface 46 of the air duct 40 is provided with a light-shielding coating 70 here, which largely absorbs visible light and prevents unwanted light reflection.

[0047] On the upper end of the air duct 40, a curved longitudinal axial section 50 connects to the straight longitudinal axial section 44 of the air duct 10. The air exit opening 43 is thus oriented essentially horizontally in the direction of the upper edge of the cover plate 11. An angle of curvature 52 between the straight longitudinal axial section 44 of the air duct 10 and the curved longitudinal axial section 50 is slightly larger than 90° here.

[0048] A radiation emitter 60, which is embodied as cost-efficient halogen light source 65 here, is arranged on the lower end of the air duct 40 in the region of the air entry opening 42. During the operation of the radiation emitter 60, the heated-up air rises up from bottom to top in the arrow direction 41 within the air duct 40, and leaves the air duct 40 downstream from the curved longitudinal axial section 50 through the air exit opening 43. In FIG. 1, a convection flow is outlined in a dashed manner, according to which the heated-up air in the housing interior of the headlight housing 10 flows along the inner side of the cover plate 11, is cooled down there, and reaches into the air duct 40 on the lower edge of the headlight housing 10, again through the air entry opening 42. In the air duct 40, the air, in turn, is heated up by the radiation emitter 60 and rises up again to the top in the arrow direction 43.

[0049] FIG. 2 shows possible versions of air ducts 40 with a curved (FIG. 2a) or a bent (FIG. 2b) longitudinal axial section in schematic drawings. The air ducts 40, which are illustrated purely schematically here, are to be understood as possible alternatives for the installation, for example into the headlight 1 shown in FIG. 1.

[0050] In FIG. 2a, the curved longitudinal axial section 50, which adjoins on the upper end of the straight longitudinal axial section 44 of the air duct 40, has a radius of curvature 51 as well as angle of curvature 52. Here, the radius of curvature 51 is, for example, 10 mm—with an assumed total installation length of the air duct 40 of approximately 100 mm. Here, the angle of curvature 52 of the curved longitudinal axial section 50 is, for example, 120° with respect to the axial direction 44 of the straight longitudinal axial section of the air duct 40. In the installation position of the air duct 40, the air exit opening 43 thus points obliquely downwards. A halogen light source 65 serves a radiation emitter 60 here.

[0051] In FIG. 2b, the air duct 40 has a bend, thus a curved longitudinal axial section 55 with a radius of curvature 56 of equal to zero or of 0 mm, respectively. This bend point is located between the lower straight longitudinal axial section 44 and the longitudinal axial section 44 of the air duct 40, which connects thereto at an angle of curvature 57 or here at a bend angle 57, respectively. The selected angle of curvature 57 or the bend angle 57 here, respectively, is, for example 110°. The lower straight longitudinal axial section 44 is oriented slightly obliquely upwards here. The upper or second straight longitudinal axial section 44, respectively, is oriented essentially horizontally here. In the installation position of the air duct 40, the air exit opening 43 thus points approximately horizontally into a non-illustrated headlight housing. An infrared radiator 61 serves as radiation emitter 60 here.

[0052] FIG. 3 shows a further embodiment according to the invention of a headlight 1 according to the invention with a condensation protection device 30 as well as twice-bent air duct 40 in the installation position within a headlight housing 10. The first curved longitudinal axial section 50 forms a bend point with a radius of curvature 51 with a radius of 0 mm as well as with an angle of curvature 52 of approximately 110°. The second curved longitudinal axial section 55 of the air duct 40 forms a bend point with a radius of curvature 56 with a radius of 0 mm as well as with an angle of curvature 57 of approximately 90°. Here, the heated-up air flows obliquely upwards out of the air exit opening 43 in the arrow direction 41.

[0053] FIG. 4 shows a further embodiment according to the invention of a headlight 1 according to the invention with a condensation protection device 30 as well as a twice-curved air duct 40 in the installation position within a headlight housing 10. The first curved longitudinal axial section 50 has a radius of curvature 51 of 10 mm as well as with an angle of curvature 52 of approximately 110°. The second curved longitudinal axial section 55 of the air duct 40 has a radius of curvature 56 of 15 mm as well as an angle of curvature 57 of approximately 90°. Here, the heated-up air flows obliquely upwards out of the air exit opening 43 in the arrow direction 41. A fan blower 80 for improving the convection is additionally provided in the region of the second curved longitudinal axial section 55.

[0054] FIG. 5 shows a further embodiment according to the invention of a headlight 1 with a forked, in each case twice-curved air duct 40 of a condensation protection device 30 in the installation position within a headlight housing 10. On its opposite ends, the air duct 40 has two air exit openings 43, which are spaced apart from one another and which blow pre-heated air 41 into the interior of the headlight housing 10 on the upper and on the lower edge of the headlight housing 10. A radiation emitter 60 is located approximately centrally within the air duct 40 here.

[0055] FIG. 6 shows possible versions of air ducts 40 with a curved (FIG. 6a) or a bent (FIG. 6b) longitudinal axial section in schematic drawings. In contrast to the air ducts illustrated in FIGS. 2a and 2b, the air ducts 40 outlined here in each case have an air exit opening 43, which is formed in the form of a diffusor 75. The exit speed of the pre-heated air is reduced and evened out in a manner known per se by means of the diffusor 75. When using such air ducts 40, a particularly gentle and even heat-up of the interior of the headlight housing 10 is attained.

LIST OF REFERENCE NUMERALS

[0056] 1 headlight for a motor vehicle [0057] 10 headlight housing [0058] 11 cover plate [0059] 12 light exit opening [0060] 20 light module [0061] 21 LED light source [0062] 30 condensation protection device [0063] 40 air duct [0064] 41 air, symbolized by means of an air flow (in the arrow direction) [0065] 42 air entry opening of the air duct [0066] 43 air exit opening of the air duct [0067] 44 longitudinal axis of the air duct or longitudinal axial section, respectively [0068] 45 wall material of the air duct [0069] 46 inner surface of the air duct [0070] 50 (first) curved longitudinal axial section of the air duct [0071] 51 radius of curvature [0072] 52 angle of curvature [0073] 55 (second) curved longitudinal axial section of the air duct [0074] 56 radius of curvature [0075] 57 angle of curvature [0076] 60 radiation emitter [0077] 61 infrared radiator [0078] 65 halogen light source [0079] 70 coating on the inner surface of the air duct [0080] 75 diffusor [0081] 80 fan blower