DE102020001701B4 - headlights and headlamps - Google Patents

Abstract

Headlight with a reflector (40) and a light source (41) which is set up to emit light in a solid angle range, the reflector (40) having a reflecting surface (20) which surrounds the light source (41) at least in the aforementioned solid angle range , wherein the light source (41) comprises a light-emitting diode,wherein a first partial surface (24) of the reflecting surface (20) is shaped like a partial surface of a paraboloid of revolution (21) having an axis of rotation (22) and having a focal point (23),wherein a second partial surface (25) of the reflecting surface (20), which is located on the opposite side of the first partial surface (24) in relation to the axis of rotation (22) in the direction of a first spatial direction (Z), in relation to the first spatial direction (Z) more to the axis of rotation (22) is curved towards than the paraboloid of revolution (21), wherein the first spatial direction (Z) is perpendicular to the axis of rotation (22), and wherein a third partial surface (26) of the reflecting surface (2 0) has an elevation tapering to a point in relation to the first spatial direction (Z) and in relation to a second spatial direction (Y), the tip of which is oriented towards the light source (41), the elevation being asymmetrical in relation to the first spatial direction (Z), the second spatial direction (Y) is perpendicular to the axis of rotation (22) and perpendicular to the first spatial direction (Z).

Description

The invention relates to a headlight and a headlamp, in particular a headlight and a headlamp, which are suitable for outdoor sports enthusiasts due to their lighting characteristics and their compact design.

Lamps are known from the prior art that are suitable for generating a long-range, focused beam of light ( EP 1 631 769 B1 ). How out 1a and from 1b However, as becomes clear, a focused beam of light is not suitable for illuminating the ground in the immediate vicinity of the lamp well. Even a light beam that is significantly less concentrated and inclined towards the ground is only suitable to a limited extent for illuminating the ground at close range, as in 2a and in 2 B is recognizable. Next are from the prior art ( EP 1 422 468 A2 ) Headlamps with multiple light sources are known in order to be able to illuminate multiple areas at the same time. The disadvantage, however, is that such headlamps either illuminate too large an area, which is associated with a higher consumption of electrical energy, or that individual light cones overlap or are separated from one another, so that the lighting on the ground in the close-up area is uneven.

Out of U.S. 1,292,637 A , U.S. 1,306,511 A and U.S. 1,631,610 A Asymmetrically constructed headlights with several paraboloid or ellipsoid sub-areas are known, which can be used as low beams in vehicles. DE 84 06 285 U1 shows an asymmetrical reflector for flashlights. In U.S. 5,394,317A a rectangular ceiling light is shown with a boss extending towards the light source. Next shows US 2015/0 146 429 A1 a rotationally symmetric Fresnel-like reflector derived from a paraboloid. Out of DE 10 2015 102 114 A1 a helmet lamp with a reflector and several light sources is known. In US 2012/0 287 629 A1 and US 2010/0 290 222 A1 lamps are shown in which the light source is directed onto a rotationally symmetrical reflector. Out of DE 35 43 322 A1 a display device with a transparent circuit board is known.

The invention specified in claim 1 is based on the problem of generating a forward-directed, bundled light beam with only one light source, and at the same time illuminating the ground as evenly as possible in a limited area. The light generated by the light source should be used as efficiently as possible.

The above problem is solved by a headlight according to claim 1 and by a headlamp according to claim 9. Further embodiments of the invention are specified in the dependent claims, the description and the figures.

A headlamp with a headlight according to the invention has the advantage that, through the use of a light source directed towards a reflector, all the light emitted by the light source is reflected in the desired direction, as in the specific case, concentrated forwards and in a limited area downwards, so that you can look ahead into the distance and at the same time the ground is clearly visible, for example to be able to perceive obstacles. An annoying switching between different types of lighting and an adjustment of the angle of inclination to the ground is not necessary with the headlight according to the invention. The targeted lighting largely avoids the emission of light horizontally to the side and upwards. In addition, the headlamp according to the invention realizes a seamless transition between the focused light beam directed forward and the light directed to an area on the ground, thereby eliminating a dark gap where nothing can be seen in the dark. Disturbing areas that are too bright or too dark are avoided due to the uniform illumination of the ground with the headlight according to the invention. By specifically illuminating a limited area, no electrical energy is wasted with superfluous light, which means that a battery-operated headlamp can burn for longer with the same level of illumination. Since the headlight according to the invention consists of only a few components, it is light and compact. In addition, the headlight of the present invention is waterproof, so it does not necessarily need to be built into a case, and heat generated from the light source is easily emitted to the outside.

A headlight according to the invention has a reflector and a light source. In a preferred embodiment of the invention, the headlight has exactly one reflector and/or exactly one light source. The light source, which includes a light-emitting diode, is set up to emit light in a solid angle range. The solid angle range is usually predetermined by the design of the light source. The reflector has a reflecting surface that surrounds the light source at least in the aforementioned solid angle range. This means that the reflecting surface of the reflector is adapted to the emission characteristics of the light source. In other words, the reflective surface is shaped and positioned relative to the light source in such a way that all light emitted by the light source strikes the reflective surface directly. In a preferred embodiment of the invention surrounds the reflective Surface the light source at a distance of at least 1 mm.

A first patch of the reflective surface is shaped like a patch of a paraboloid of revolution having an axis of rotation and having a focus. It is possible to approximate the first partial surface of the reflecting surface by a partial surface of a spherical surface or by facets without significantly changing the optical properties of the first partial surface. Light coming from the focal point and hitting the first partial surface is reflected in the direction of the axis of rotation (X-direction). The light source is preferably positioned on the axis of rotation in such a way that light emitted by the light source and impinging on the first partial surface is reflected as a bundled light beam in the direction of the axis of rotation. Typically, the proportion of the first partial area in the total reflecting area is at least 20%. Preferably, the portion of the first partial area of the total reflecting area is between 30% and 60%. The area proportion correlates with the light proportion of the bundled light beam.

A second partial surface of the reflecting surface, which is located on the opposite side of the first partial surface with respect to the axis of rotation in the direction of a first spatial direction (Z-direction), is curved more towards the axis of rotation with respect to the first spatial direction than the paraboloid of revolution. In other words: a point on the second partial surface is at a smaller distance perpendicular to the axis of rotation than a point on the first partial surface, the two points being opposite one another with respect to the first spatial direction and with respect to the axis of rotation. The first spatial direction is perpendicular to the axis of rotation. Due to the asymmetry with respect to the first spatial direction of the reflecting surface, the light emitted by the light source is reflected asymmetrically with respect to the first spatial direction. For example, light emitted by the light source is partially reflected by the second partial surface at an angle to the axis of rotation of more than 60° and asymmetrically with respect to the first spatial direction. Typically, light emitted by the light source is asymmetrically reflected by the reflecting surface at an angle to the axis of rotation in the range of 10° to 75°.

A third partial surface of the reflecting surface has an elevation tapering to a point with respect to the first spatial direction and with respect to a second spatial direction (Y-direction), the tip of which is aligned towards the light source. As a result, most of the light emitted by the light source and impinging on the third sub-area near the axis of rotation is reflected past the light source and is therefore not reflected back to the light source. The elevation is preferably formed asymmetrically with respect to the first spatial direction. Thus, light emitted by the light source and impinging on the third partial area is reflected asymmetrically with respect to the first spatial direction.

There is also the possibility that the reflecting surface is partially wavy. As a result, the light emitted by the light source and asymmetrically reflected by the reflecting surface results in a more uniform brightness distribution on a projection surface (for example on the floor) which has the first spatial direction as the surface normal. The partial areas mentioned above can be corrugated in whole, in part or not at all.

In a preferred embodiment of the invention, the entire reflecting surface is without gaps and/or without holes and/or without edges and/or without steps. The entire light emitted by the light source and reflected by the reflecting surface thus preferably produces a coherent or continuous brightness distribution on any projection surface (for example on the floor or on a wall).

In a typical embodiment of the invention, the reflecting surface is symmetrical with respect to the second spatial direction (Y-direction), the second spatial direction being perpendicular to the axis of rotation and perpendicular to the first spatial direction. The light emitted by the light source is thereby preferably reflected symmetrically with respect to the second spatial direction.

In a preferred embodiment of the invention, the light source is positioned on the axis of rotation and/or at the focal point. Furthermore, the light source can be directed to the point of intersection of the axis of rotation with the paraboloid of revolution. Typically, the light source is designed to emit light in one hemisphere. This means, for example, that the reflecting surface surrounds the light source at least halfway, so that all of the light emitted by the light source strikes the reflecting surface directly.

In a preferred embodiment of the invention, the distance perpendicular to the axis of rotation with respect to the first spatial direction from the focal point to the closest point on the reflecting surface is at most 80% of the distance perpendicular to the axis of rotation with respect to the first spatial direction from the focal point to the furthest point on the reflecting surface. Typically, there are exactly two opposite points. The reduced (to 80%) distance allows that from the headlight Light is emitted significantly asymmetrically with respect to the first spatial direction.

In a typical embodiment of the invention, the headlight also includes two electrical lines and a windscreen. The windscreen is translucent, for example crystal clear or matt, so that light coming from the reflective surface exits the headlight. The light source preferably comprises a light-emitting diode which is electrically conductively connected to one end of each of the two electrical lines. The light-emitting diode and the two electrical lines are also attached to the windscreen. The reflector and the front pane preferably directly adjoin one another, so that a volume is enclosed into which the light-emitting diode protrudes. This ensures that the light-emitting diode and the reflecting surface are protected from moisture or dirt. Typically, the two electrical lines each run from the light-emitting diode to at least the edge of the reflecting surface of the reflector, so that the headlight can be connected to a voltage source. There is also the possibility that the windscreen together with the light source is tilted with respect to the first spatial direction, and the reflector or the reflecting surface have a corresponding shape, so that the reflector is directly adjacent to the windscreen or that all the light emitted by the light source falls directly on the hits a reflective surface. The result of this is preferably that the proportion of light reflected asymmetrically with respect to the first spatial direction is higher or lower than when the front pane is aligned in the direction of the first spatial direction.

In an alternative embodiment of the invention, the headlight also includes a transparent printed circuit board with at least two conductor tracks. The light source preferably comprises a light-emitting diode which is electrically conductively fastened (for example soldered) to one end of each of the two conductor tracks. Preferably, the reflector and the transparent printed circuit board are directly adjacent to one another, so that a volume is enclosed into which the light-emitting diode protrudes. The circuit board and reflector can be either permanently or detachably connected to each other. Typically, the two conductor tracks each run from the light-emitting diode to at least the edge of the reflecting surface. In one embodiment, the circuit board is shaped to flush the reflector. Alternatively, the printed circuit board protrudes beyond the reflector, so that further electronic components, such as a series resistor, can be attached to the printed circuit board in an electrically conductive manner outside the illuminated area of the printed circuit board.

If the light-emitting diode is intended for operation with high power, for example with 1 W or more, then in a further embodiment of the invention a heat sink is additionally used to cool the light-emitting diode. The heat sink is preferably attached to the side of the front pane or the printed circuit board that faces away from the reflector and is in thermal contact with the light-emitting diode. A heat sink positioned on the outside of the headlight has the advantage that waste heat from the light-emitting diode can be dissipated more effectively into the environment. The heat sink is preferably positioned on the axis of rotation and/or has a contact surface that is the same size or smaller than the light source. This preferably prevents the light emerging from the headlight from hitting the heat sink.

Since the positioning and orientation of the light source and the reflector relative to each other should be as precise as possible, a further embodiment of the invention has additional means for positioning. These means can include, for example, indentations, holes and/or pegs and/or notches and/or an additional frame that accommodates the windscreen and the reflector with a precise fit. Depressions in the form of grooves, in which the electrical conductors are embedded, preferably serve to position the electrical conductors. In the case of the printed circuit board, soldering areas or bores can be provided for positioning, in which components can be inserted or soldered.

A headlamp according to the invention comprises a headlight as mentioned above. Preferably, part of the headlight forms part of the outer wall of the headlamp. The light source is typically set up to emit white light. The headlamp is preferably battery-operated and/or accumulator-operated. The headlight is preferably at least 8 mm wide and/or at most 80 mm wide and/or at least 7 mm high and/or at most 70 mm high and/or at least 4 mm deep and/or at most 20 mm deep. The above dimensions refer to the external dimensions of the complete headlight, excluding the (possibly existing) connection cable.

When the axis of rotation is aligned horizontally and the first spatial direction is aligned vertically, the headlight according to the invention preferably emits more light downwards than upwards, with the first spatial direction being aligned such that the first partial area is below and the second partial area is above the axis of rotation.

When the headlight is positioned at a height of 1.7 m, a long-distance area with a horizontal distance of more than 10 m from the headlight is preferably illuminated by concentrated light, and at the same time the ground is preferably homogeneously illuminated in a close-up area with a horizontal distance of less than 5 m from the headlight. Furthermore, there is preferably a transition area between the close-up range and the long-range range, in which the homogeneous illumination of the floor merges continuously or fluently into the bundled light beam. An area of at least 16 m ² is preferably uniformly illuminated on the ground.

• 1a zeigt eine Helligkeitsverteilung am Boden gemäß dem Stand der Technik.
• 1b zeigt eine Helligkeitsverteilung an einer Wand gemäß dem Stand der Technik.
• 2a zeigt eine Helligkeitsverteilung am Boden gemäß dem Stand der Technik.
• 2b zeigt eine Helligkeitsverteilung an einer Wand gemäß dem Stand der Technik.
• 3a zeigt eine erfindungsgemäße Helligkeitsverteilung am Boden.
• 3b zeigt eine erfindungsgemäße Helligkeitsverteilung an einer Wand.
• 4a zeigt eine Seitenansicht einer erfindungsgemäßen reflektierenden Fläche.
• 4b zeigt eine Frontalansicht einer erfindungsgemäßen reflektierenden Fläche.
• 5a zeigt eine Seitenansicht einer erfindungsgemäßen Scheinwerferanordnung.
• 5b zeigt eine Frontalansicht einer erfindungsgemäßen Scheinwerferanordnung.

An exemplary embodiment of the invention is illustrated and described in more detail below with reference to the drawings.

• 1a shows a brightness distribution on the ground according to the prior art.
• 1b shows a brightness distribution on a wall according to the prior art.
• 2a shows a brightness distribution on the ground according to the prior art.
• 2 B shows a brightness distribution on a wall according to the prior art.
• 3a shows a brightness distribution on the ground according to the invention.
• 3b shows a brightness distribution according to the invention on a wall.
• 4a shows a side view of a reflecting surface according to the invention.
• 4b shows a front view of a reflecting surface according to the invention.
• 5a shows a side view of a headlight arrangement according to the invention.
• 5b shows a front view of a headlight arrangement according to the invention.

1a until 3b each show brightness distributions on projection surfaces. The larger a box is, the more light hits the projection surface at the corresponding point. In all cases, the light source is at the point X = 0 m, Y = 0 m and Z = 1.7 m, which is assumed to be the height of a used headlamp above the ground (Z = 0 m). In the case of 1a , 2a and 3a is the projected area of the floor (Z = 0 m), and in the case of 1b , 2 B and 3b the projection surface is a wall 5 m away.

show it 1a and 1b Brightness distributions of a conventional headlight with a light source directed at a paraboloid of revolution, which is located at the focal point of the paraboloid of revolution. Since the light source is not in the form of a point, a light beam 14 that is not perfectly focused is produced, which becomes wider as the distance from the light source increases. When the bundled light beam 14 is aligned horizontally, the ground is only illuminated in the far range 13 . The close-up area 11 and the transitional area 12 remain unilluminated, so that the area 15 close to the ground is also not illuminated on the wall 5 m away.

When using a less collimated light beam 14, which is inclined by 20° downwards, as in 2a and 2 B shown, the near area 11 and the transition area 12 are illuminated (also known from the prior art). However, the brightness decreases rapidly as the distance from the headlight increases, so that the long-distance area 13 is only insufficiently illuminated. As in 2 B recognizable, a lot of light is lost sideways and upwards. Furthermore, the illumination in the close-up area 11 is very uneven, so that even a combination of the two aforementioned headlights only enables suboptimal illumination.

3a and 3b show brightness distributions of a headlight according to the invention with a horizontal alignment of a bundled light beam (as in 1a and 1b ). The long-distance area 13 is illuminated with a focused light beam 14 , the close-up area 11 is evenly illuminated on the ground, and in a transitional area 12 the brightness distributions go smoothly from the ground lighting 15 to the focused light beam 14 . Next is in 3b recognizable that the light is emitted mainly forward as a bundled light beam 14 and downward as floor lighting 15 . Little light is emitted to the sides and upwards (as intended). In particular from 3b it can be seen that the light is emitted asymmetrically with respect to the spatial direction Z and symmetrically with respect to the spatial direction Y by the headlight according to the invention.

4a and 4b show a reflecting surface 20 according to the invention, which is suitable for the brightness distributions 3a and 3b to create. 4a Fig. 13 shows a side view (section through the center with respect to Y) of the reflecting surface 20, which is partially in the shape of a paraboloid of revolution 21 with an axis of rotation 22 and with a focal point 23. Figs. Light coming from the focal point 23 is reflected 31 by this part of the reflecting surface 24 parallel to the axis of rotation 22. For a real light source which is not point-like, the reflected light is (contrary to the idealized representation) not quite parallel to the axis of rotation 22. It depends , where the light source is positioned on the axis of rotation 22, the light is reflected as a more or less bundled beam of light. Furthermore, the reflecting surface 20 according to the invention is curved more towards the axis of rotation 22 in a region 25 than the paraboloid of rotation 21, as a result of which light coming from the focal point 23 is reflected more downwards 32. The embodiment of the reflecting surface 20 shown has a tapered point in the middle Elevation 26 extending towards focal point 23, whereby light coming from focal point 23 is reflected past a light source (not shown) 33. The elevation is asymmetrical with respect to the spatial direction Z, so that more light is reflected downwards than upwards.

4b 12 is a front view of the reflecting surface 20 of the present invention. The paraboloid of revolution 21 is also shown for comparison. In addition to the outline of the reflecting surface 20, two further lines are shown at constant X values. The partial surface 24 in the lower area has the shape of a paraboloid of revolution 21. The partial surface 25 of the reflecting surface 20 according to the invention can be seen at the top, the distance from which to the axis of rotation 22 is less than the distance of the paraboloid of rotation 21 to the axis of rotation 22 pointed elevation shown, which is aligned to the focal point, and which is asymmetrical with respect to the Z spatial direction and symmetrical with respect to the Y spatial direction. This partial surface 26 is typically located in the area around the axis of rotation 22. In the exemplary embodiment of the invention, the elevation has concave surface areas. Additionally, portions 27 of the exemplary reflective surface 20 are corrugated to more evenly distribute the light. Overall, the reflecting surface 20 shown is symmetrical with respect to the spatial direction Y, which means that the right half and the left half of the reflecting surface 20 are mirror-symmetrical. In addition, the reflecting surface 20 shown is asymmetrical with respect to the spatial direction Z, which is equivalent to the fact that the upper half and the lower half of the reflecting surface 20 are not mirror-symmetrical.

5a and 5b show a headlight according to the invention in a side view (section through the middle with respect to Y) or a front view. The reflector 40 and the light source 41 are positioned and aligned with one another in such a way that all of the light emitted by the light source 41 impinges on the reflecting surface 20 . In the exemplary embodiment of FIG 5a and from 5b is used as the light source 41, a light emitting diode in SMD construction. The light-emitting diode 41 is attached to a translucent front panel 42 and positioned on the axis of rotation 22 . In the specific example, the center of the light-emitting surface of the light-emitting diode 41 is positioned at the focal point 23 . Furthermore, the light-emitting diode 41 is connected to two electrical lines 44 and 45 which run from the light-emitting diode 41 to at least the edge of the reflector 40 . The headlight can be connected to a suitable voltage source via the two electrical lines 44 and 45 . In the exemplary embodiment of the invention shown, the translucent front pane 42 has indentations into which the light-emitting diode 41 and the electrical lines 44 and 45 are embedded, which enables precise positioning of the light-emitting diode 41 or the electrical lines 44 and 45 . The reflector 40 and the front pane 42 enclose a volume into which the light-emitting diode 41 protrudes, so that both the light-emitting diode 41 and the reflecting surface 20 of the reflector 40 are protected from moisture and dirt. In the embodiment shown, the two electrical lines 44 and 45 run on the outside of the headlight, so that the heat produced by the light-emitting diode 41 is emitted more easily to the environment. In the immediate vicinity of the light-emitting diode 41, the front pane 42 has passages for the electrical lines 44 and 45, so that the electrical lines 44 and 45 and the light-emitting diode 41 have electrical contact (eg by soldering or conductive silver). If the light-emitting diode 41 is operated with relatively high power, a heat sink 43 which is in thermal contact with the light-emitting diode 41 is also used. For better heat dissipation to the environment, the heat sink 43 is preferably attached to the outside of the headlight directly behind the light-emitting diode 41.

reference list

11

close range

12

transition area

13

far range

14

focused beam of light

15

ground level area

20

reflective surface

21

paraboloid of revolution

22

axis of rotation

23

focus

24

first face

25

second part

26

third area

27

wavy part

31

first beam path

32

second beam path

33

third beam

40

reflector

41

light source

42

windscreen

43

heatsink

44

electrical line

45

electrical line

X

third spatial direction

Y

second spatial direction

Z

first spatial direction

Claims (9)

Headlight with a reflector (40) and a light source (41) which is set up to emit light in a solid angle range, the reflector (40) having a reflecting surface (20) which surrounds the light source (41) at least in the aforementioned solid angle range , wherein the light source (41) comprises a light-emitting diode, wherein a first partial surface (24) of the reflecting surface (20) is shaped like a partial surface of a paraboloid of revolution (21) with an axis of rotation (22) and with a focal point (23), wherein a second partial surface (25) of the reflecting surface (20), which is located on the opposite side of the first partial surface (24) with respect to the axis of rotation (22) in the direction of a first spatial direction (Z), with respect to the first spatial direction (Z) more is curved toward the axis of rotation (22) than the paraboloid of rotation (21), the first spatial direction (Z) being perpendicular to the axis of rotation (22), and wherein a third partial surface (26) of the reflecting surface (20) has an elevation tapering to a point in relation to the first spatial direction (Z) and in relation to a second spatial direction (Y), the tip of which is aligned towards the light source (41), the elevation being asymmetrical is shaped with respect to the first spatial direction (Z), the second spatial direction (Y) being perpendicular to the axis of rotation (22) and perpendicular to the first spatial direction (Z). headlights after claim 1 , wherein the reflecting surface (20) is partially corrugated (27). Headlights after one of Claims 1 until 2 , wherein the entire reflective surface (20) is gapless and / or edge-free. Headlights after one of Claims 1 until 3 , wherein the reflecting surface (20) is symmetrical with respect to the second spatial direction (Y). Headlights after one of Claims 1 until 4 , wherein the light source (41) is positioned on the axis of rotation (22). Headlights after one of Claims 1 until 5 , wherein the distance perpendicular to the axis of rotation (22) with respect to the first spatial direction (Z) from the focal point (23) to the nearest point of the reflecting surface (20) is at most 80% of the distance perpendicular to the axis of rotation (22) with respect to the first spatial direction (Z ) from the focal point (23) to the farthest point of the reflecting surface (20). Headlights after one of Claims 1 until 6 with two additional electrical lines (44, 45) and a windscreen (42), the light-emitting diode (41) being electrically conductively connected to one end of each of the two electrical lines (44, 45), the light-emitting diode (41) and the two electrical lines (44, 45) are attached to the front pane (42), the front pane (42) being translucent, the reflector (40) and the front pane (42) directly adjoining one another so that a volume is enclosed in which the The light-emitting diode (41) protrudes, and the two electrical lines (44, 45) each run from the light-emitting diode (41) to at least the edge of the reflecting surface (20) of the reflector (40). Headlights after one of Claims 1 until 6 with an additional transparent printed circuit board, the transparent printed circuit board comprising at least two conductor tracks, the light-emitting diode (41) being electrically conductively attached to one end of each of the two conductor tracks, and the reflector (40) and the transparent printed circuit board directly adjoining one another, so that a Volume is enclosed, in which the light-emitting diode (41) protrudes. Headlamp with a headlight according to one of the Claims 1 until 8th .

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