Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A HEADLAMP FOR VEHICLES
Document Type and Number:
WIPO Patent Application WO/2019/120565
Kind Code:
A1
Abstract:
A headlamp for vehicles, comprising at least one light source (1) for generating at least one light beam (9), a scanning device (10) for one-dimensionally scanning the at least one light beam (9) bidirectionally in a scanning direction, and an array (14) of optical elements (15), which are arranged side by side in a direction that corresponds to the scanning direction, so that the at least one light beam (12) impinges on the optical elements (15) successively, wherein at least some of the optical elements (15) are designed to expand the at least one light beam (12) in a direction perpendicular to the direction, in which the optical elements (15) are arranged side by side.

Inventors:
BURSY, Marcel (Messingstr. 21c, Schwerte, 58239, DE)
GIEHL, Markus (Overhagenerstr. 25, Lippstadt, 59557, DE)
HANSEN, Julien (Franz-Egon-Str. 1, Paderborn, 33102, DE)
KAUP, Marc (Penzlinger Str. 19, Paderborn, 33102, DE)
RETTWEILER, Thomas (Mörikeweg 3, Lippstadt, 59555, DE)
SCHMIDT, Christian (Am Richterbusch 21 b, Paderborn, 33106, DE)
SMARSLIK, Christian (Dr.-Zahn-Straße 6, Lippstadt, 59555, DE)
STROOP, Philip (Oerlinghauser Straße 93a, Schloß Holte-Stukenbrock, 33758, DE)
WILKS, Carsten (Uhlandstraße 11, Lippstadt, 59555, DE)
WILLEKE, Benjamin (Langesche Wiese 35, Lippstadt, 59557, DE)
Application Number:
EP2017/084380
Publication Date:
June 27, 2019
Filing Date:
December 22, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
HELLA GMBH & CO. KGAA (Rixbecker Straße 75, Lippstadt, 59552, DE)
International Classes:
F21S41/125; F21S41/16; F21S41/20; F21S41/675
Domestic Patent References:
WO2013099144A12013-07-04
WO2014121314A12014-08-14
WO2014121314A12014-08-14
Foreign References:
US20110249460A12011-10-13
DE102014223933A12016-05-25
US20160018066A12016-01-21
EP3096074A12016-11-23
US20150375672A12015-12-31
US20070177250A12007-08-02
Download PDF:
Claims:
A headlamp for vehicles

Patent claims

1. A headlamp for vehicles, comprising

- at least one light source (1 ) for generating at least one light beam (9),

- a scanning device (10) for one-dimensionally scanning the at least one light beam (9) bidirectionally in a scanning direction,

characterized in that the headlamp further comprises an array (14) of optical elements (15), which are arranged side by side in a direction that corre- sponds to the scanning direction, so that the at least one light beam (12) im- pinges on the optical elements (15) successively, wherein at least some of the optical elements (15) are designed to expand the at least one light beam (12) in a direction perpendicular to the direction, in which the optical ele- ments (15) are arranged side by side.

2. The headlamp according to claim 1 , characterized in that at least one or some of the optical elements (15) are lenses and/or prisms and/or plates.

3. The headlamp according to claim 2, characterized in that an optical element

(15) designed as a lens is a spherical lens or a cylindrical lens or an anamor- phic lens.

4. The headlamp according to one of claims 1 to 3, characterized in that the scanning frequency of the scanning device (10) is greater than the flicker fusion frequency, so that the emitted light distribution appears steady to an observer, wherein in particular the scanning frequency of the scanning de- vice (10) is greater than 200 Hz.

5. The headlamp according to one of claims 1 to 4, characterized in that the at least one light source (1 ) is a laser light source, especially an RGB laser light source, wherein in particular the RGB laser light source comprises three sin- gle lasers (2, 3, 4), which emit a red, a green and a blue laser beam, respec- tively, wherein the laser beams of the three lasers are being overlapped so that a single white laser beam is emitted by the RGB laser light source.

6. The headlamp according to claim 5, characterized in that the headlamp corn- prises optical means for overlapping and for guiding the laser beams, where- in in particular the headlamp comprises an optical fiber coupler (5) for over- lapping the laser beams of the three lasers (2, 3, 4) and three optical fibers (6, 7, 8) arranged between the three lasers (2, 3, 4) and the fiber coupler (5) for directing the laser light to the fiber coupler (5).

7. The headlamp according to one of claims 1 to 6, characterized in that the headlamp comprises a plurality of optical fibers arranged between the scan- ning device (10) and the array (14) of optical elements (15) for directing the scanned light beam (12) to the optical elements (15), wherein in particular one of the optical fibers is assigned to one of the optical elements (15).

8. The headlamp according to one of claims 1 to 7, characterized in that the headlamp comprises more than one array (14) of optical elements (15), wherein the arrays (14) are arranged above each other in a direction perpen- dicular to the direction, in which the optical elements (15) are arranged side by side.

9. The headlamp according to one of claims 1 to 8, characterized in that the headlamp comprises more than one light source (1 ), wherein in particular one of the light sources (1 ) is assigned to one of the arrays (14) of optical elements (15).

10. The headlamp according to one of claims 1 to 9, characterized in that the headlamp comprises control means for controlling the at least one light source (1 ) according to the scanning of the at least one light beam (9), wherein in particular the intensity or the color of the at least one light beam (9) can be changed to achieve a favored light distribution pattern (13).

Description:
A headlamp for vehicles

Description

The present invention relates to a headlamp for vehicles according to the preamble of claim 1.

A headlamp of the aforementioned type is known from WO 2014/121314 A1. This headlamp comprises four laser light sources for generating laser beams and a micro- mirror device for one-dimensionally scanning the laser beams bidirectionally in a scanning direction. The scanned laser beams impinge on conversion means for con- verting the laser light into white light. The headlamp further comprises a projection system for projecting the converted light onto the road in front of the vehicle. The con- version means cause considerable losses. Furthermore the color of the converted light cannot be changed. Additionally a relatively big projection system is needed for pro- jecting the converted light onto the road.

Another headlamp is known from US 2007/0177250 A1. This headlamp comprises a light source for generating a light beam and micro-mirrors for two-dimensionally scan- ning the light beam in two directions, which are perpendicular to each other, in espe- cially in a horizontal and a vertical direction. Thus the headlamp can achieve a two- dimensional light distribution pattern in front of the vehicle. For providing a high resolu- tion light distribution pattern the micro-mirror has to move very fast and the light source must be a high-power light source.

The problem to be solved by the present invention is thus to provide a headlamp of the aforementioned kind, which can achieve a two-dimensional light distribution pat- tern in front of the vehicle, in particular a high resolution light distribution pattern, more effectively. This is attained with the invention by a headlamp of the aforementioned kind with the characterizing features of claim 1. The dependent claims relate to preferred embodi- ments of the invention.

According to claim 1 , the headlamp further comprises an array of optical elements, which are arranged side by side in a direction that corresponds to the scanning direc- tion, so that the at least one light beam impinges on the optical elements successively, wherein at least some of the optical elements are designed to expand the at least one light beam in a direction perpendicular to the direction, in which the optical elements are arranged side by side. Thus despite of the only one-dimensional scanning of the at least one light beam the optical elements can contribute to a two-dimensional light distribution pattern in front of the vehicle.

Within the vehicle the optical elements may be arranged side by side in a horizontal direction, whereas the optical elements can expand the at least one light beam in the vertical direction. Due to this orientation of the optical elements the light-emitting sur- face of the headlamp is elongated in an horizontal direction and quite narrow in the vertical direction. This can result in an attractive design of the headlamp.

In particular, at least one or some of the optical elements may be lenses and/or prisms and/or plates. For instance an optical element designed as a lens may be a spherical lens or a cylindrical lens or an anamorphic lens. Such elements are able to expand the at least one light beam effectively.

The potential exists that the scanning frequency of the scanning device is greater than the flicker fusion frequency, so that the emitted light distribution appears steady to an observer, wherein in particular the scanning frequency of the scanning device is greater than 200 Hz. Due to a scanning frequency of more than 200 Hz the scanned light beam results in a light distribution pattern, which an observer perceives as a stat- ic light distribution pattern. It may be provided that the at least one light source is a laser light source, especially an RGB laser light source, wherein in particular the RGB laser light source comprises three single lasers, which emit a red, a green and a blue laser beam, respectively, wherein the laser beams of the three lasers are being overlapped so that a single white laser beam is emitted by the RGB laser light source. The RGB laser light source might be able to generate an output beam with a predetermined color temperature or a temporally altering color temperature. Therefore, a light distribution pattern with dif ferent colors may be provided.

In an alternative embodiment the at least one light source could be a laser light source with conversion means for producing white light. In a further alternative embodiment the at least one light source could be a LED.

The potential exists that the headlamp comprises optical means for overlapping and for guiding the laser beams, wherein in particular the headlamp could comprise an optical fiber coupler for overlapping the laser beams of the three lasers and three opti- cal fibers arranged between the three lasers and the fiber coupler for directing the la- ser light to the fiber coupler. The optical fiber coupler reliably ensures the overlapping of the laser beams.

It is furthermore possible that the headlamp comprises a plurality of optical fibers ar- ranged between the scanning device and the array of optical elements for directing the scanned light beam to the optical elements, wherein in particular one of the optical fibers is assigned to one of the optical elements. This configuration may facilitate the arrangement of the components in the headlamp. Additionally, more degrees of free- dom are achieved for designing the headlamp.

It may be provided that the headlamp comprises more than one array of optical ele- ments, wherein the arrays are arranged above each other in a direction perpendicular to the direction, in which the optical elements are arranged side by side. Especially in this case the headlamp could comprise more than one light source, wherein in particu- lar one of the light sources is assigned to one of the arrays of optical elements. The potential exists that the headlamp comprises control means for controlling the at least one light source according to the scanning of the at least one light beam, where- in in particular the intensity or the color of the at least one light beam can be changed to achieve a favored light distribution pattern. Thus the light distribution pattern can be designed very flexibly.

Preferred exemplary embodiments of the invention are described below in detail by means of the enclosed drawings. The drawings show: figure 1 a schematic diagram of a headlamp according to the invention; figure 2 a schematic diagram similar to figure 1 with a schematically indicated light distribution pattern.

In the figures, identical or functionally identical parts or light beams are designated with identical reference numerals.

The headlamp illustrated in figure 1 comprises a light source 1 being an RGB laser light source having three single lasers 2, 3, 4, which emit a red, a green and a blue laser beam, respectively. The RGB laser light source is provided with an optical fiber coupler 5 for overlapping the laser beams of the three lasers 2, 3, 4. The light source 1 further comprises three optical fibers 6, 7, 8 arranged between the three lasers 2, 3, 4 and the fiber coupler 5 for directing the laser light to the fiber coupler 5.

Due to the color of the three lasers 2, 3, 4 the RGB laser light source emits an output light beam 9 having a color temperature which corresponds to white light. The light beam 9 has a comparatively small diameter and possesses only a small divergence. The headlamp comprises control means which are not shown in the figures. The con- trol means can drive the three individual lasers 2, 3, 4 accordingly to generate a light beam 9 with a predetermined color temperature. Furthermore, the headlamp illustrated in figure 1 comprises scanning device 10 for one-dimensionally scanning the light beam 9 bidirectionally in a scanning direction, which is located in the plane of projection of figure 1. Within the vehicle the scanning direction is located in a horizontal plane. The scanning device 10 could be a galva- nometer scanner or a MEMS mirror. Figure 1 schematically shows a mirror 11 , which can be tilted around an axis perpendicular to the plane of projection of figure 1. In fig- ure 1 several different positions of the scanned beam 12 are illustrated.

The scanning frequency of the scanning device 10 should be greater than 200 Flz.

Due to a scanning frequency of more than 200 Hz the scanned light beam 12 results in a light distribution pattern 13 (see figure 2), which an observer perceives as a static light distribution pattern.

Furthermore, the headlamp illustrated in figure 1 comprises an array 14 of at least par- tially transparent optical elements 15, which are arranged side by side in a direction that corresponds to the scanning direction. Therefore, the scanned light beam 12 im- pinges on the optical elements 15 successively (see figure 1 and figure 2).

At least one or some of the optical elements 15 may be lenses and/or prisms and/or plates. For instance an optical element 15 designed as a lens may be a spherical lens or a cylindrical lens or an anamorphic lens. Such elements 15 are able to expand the light beam 12 in a direction perpendicular to the direction, in which the optical ele- ments 15 are arranged side by side. Within the vehicle the optical elements 15 are arranged side by side in a horizontal direction, whereas at least some of the optical elements 15 expand the light beam 12 in the vertical direction.

The optical elements 15 can differ from each other. Especially at least some of the optical elements 15 can differ from each other with regard to their ability to deflect the light beam 9 in the horizontal and/or the vertical direction.

Figure 2 shows schematically a light distribution pattern 13 in front of the vehicle. The control means for controlling the RGB laser light source can change the color or the intensity of the beam 9 during the scanning of the beam 9. For instance the scanned beam 12 can be less intensive in a first angle range than in a second angle range.

Thus the control means as well as the optical elements 15 can contribute to a flexible design of the light distribution pattern 13.

In an alternative embodiment the headlamp comprises a plurality of optical fibers (not shown) arranged between the scanning device 10 and the array 14 of optical elements 15 for directing the scanned light beam 12 to the optical elements 15. In this case one of the optical fibers could be assigned to one of the optical elements 15.

In a further alternative embodiment the headlamp comprises more than one array 14 of optical elements 15 (not shown), wherein the arrays 15 are arranged above each other in the vertical direction. In this case the headlamp could comprise more than one RGB laser light sources, wherein in particular one of the RGB laser light sources is assigned to one of the arrays 14 of optical elements 15.

List of reference symbols

1 light source

2 laser for emitting a red laser beam

3 laser for emitting a green laser beam

4 laser for emitting a blue laser beam

5 optical fiber coupler

6 optical fiber

7 optical fiber

8 optical fiber

9 light beam

10 scanning device

11 mirror

12 scanned beam

13 light distribution pattern

14 array

15 optical element