EP3420269B1 - Headlight for vehicles - Google Patents

Description

The invention relates to a headlamp for vehicles, with at least one light source and one of these associated optical optics, with a micromirror array and formed as a lens imaging optics, wherein the light source and the micromirror array is associated with a central processing unit with a light source drive and an array drive in that the shaped light beams of the at least one light source are directed onto the micromirror array and that the reflected light bundle structured by the latter is projected via the imaging optics as a light image into the traffic space.

The term "headlight" is to be understood in the context of the present invention not only a complete vehicle headlight but also a lighting unit, which may form part of a headlamp, for example, together with other lighting units.

In the development of the current headlamp systems is increasingly the desire in the foreground to project a high-resolution as possible on the road, which can be quickly changed and adapted to the respective traffic, road and lighting conditions. The term "roadway" is used here for a simplified representation, because of course it depends on the local conditions, whether a photograph is actually on the road or even beyond. In principle, the photograph in the sense used here corresponds to a projection onto a vertical surface in accordance with the relevant standards relating to automotive lighting technology.

According to the mentioned need different headlamp systems have been developed, such as in particular with scanning, modulated laser beam working headlights, the lighting starting point is at least one laser light source emitting a laser beam, and which is associated with a laser drive for power supply and for monitoring the laser emission or eg is used for temperature control and is also set up to modulate the intensity of the emitted laser beam. By "modulating" it is to be understood that the intensity of the laser light source can be changed, be it pulsed continuously or in the sense of switching on and off. It is essential that the light output can be changed dynamically analogously, depending on which angular position a mirror deflecting the laser beam is. In addition, there is still the possibility of switching on and off for a certain time, not to illuminate or hide defined places. The control of the laser light sources and the micromirror serving for beam deflection takes place via a computing unit, also called ECU for short (electronic or engine control unit). An example of a dynamic drive concept for generating an image by a scanning laser beam is approximately in the document AT 514633 the applicant described.

Since such headlight systems are sometimes very complex and expensive, so that there is a desire to create economical headlights, which nevertheless have a high flexibility with regard to the generated light image, headlights have become known which use as light processing elements imagers, the large number of controllable Have pixel fields. That's how it shows DE 10 2013 215 374 A1 Solutions in which the light of a light source is directed via a light guide to an LCD imager to a LCoS chip or to a micromirror array ("DMD") to then be projected onto the lane via projection optics.

The document DE 11 2013 003 050 T5 discloses a vehicle lamp in which the light of two LEDs is directed via a respective reflector on a DMD, from where it is projected via a projection lens on the road. On the DMD different illumination patterns can be generated, which are reproduced by the projection lens on the road.

Also the document FR 3 008 477 A1 shows a vehicle lamp with a projection lens and two light sources whose light is directed to generate two light fields via two different mirror elements to the projection lens and from there into the traffic area. In this and the luminaire arrangement mentioned above, conventional lenses are used as imaging optics, in which no distinction can be made in areas of different refractive power.

DMD is an acronym used for "Digital Micromirror Device", thus for a micromirror array or micromirror matrix. Such a micromirror array has very small dimensions, typically on the order of 10 mm. In a DMD micro-mirror actuators are arranged like a matrix, wherein each individual mirror element, which for example has an edge length of about 16 microns, by a certain angle, for example 20 °, tiltable, for example by electromagnetic or piezoelectric actuators. The end positions of a micromirror are referred to as ON state and OFF state, wherein ON state means that light from the micromirror passes through the imaging optics on the road, whereas in the OFF state, for example, it is directed to an absorber. Usually, it is also necessary to ensure absorption of those light beams which emanate from micromirrors in their non-"active" angular position and which are not projected onto the road via the imaging optics. For this purpose, absorbers or absorber surfaces are used, which absorb the otherwise harmful light rays and convert them into heat.

Each micromirror is individually adjustable in angle, whereby between the end positions within a second up to 5000 times can be changed. The number of mirrors corresponds to the resolution of the projected image, where a mirror can represent one or more pixels. Meanwhile, DMD chips with high resolutions in the megapixel range are available. The underlying technology for single-level variable mirrors is Micro-Electro-Mechanical Systems (MEMS) technology.

While the DMD technology has two stable mirror states and a modulation between the two stable states, the reflections are adjusted The "Analog Micromirror Device" (AMD) technology has the property that the individual mirrors can be set in variable mirror positions.

A headlight based on a micromirror array is for example in the DE 195 30 008 A1 described.

In headlamps of motor vehicles one wants to realize in the most compact design often several light functions, such as in particular high beam, low beam, daytime running lights and cornering lights. Starting from a micromirror concept, in this case several micromirror arrays and several lenses are required for the imaging optics, which leads to high material and manufacturing costs.

The design of a luminance pattern is carried out not only via the modulation of the primary light source but also via different array controls for different light distributions, such as high beam, low beam with or without asymmetry, Ausblendszenarien etc., with different array activations activate the individual micromirror elements as a function of the desired light distribution.

An object of the invention is to provide a headlamp, which is inexpensive to produce, but still has a great freedom of design with regard to the producible photographs.

This object is achieved with a headlamp of the type mentioned, in which at least two light sources are provided according to the invention, the light beams are directed to a micromirror array common to the light sources and two superimposed areas of an imaging optics with different refractive power for two image areas of the light beam reflected by this Photograph are assigned.

Thanks to the invention, multiple light functions can be realized with a single micromirror array and a single imaging optic, which simplifies the overall design and makes it less expensive. The division into several light sources, which are usually power intensive, also facilitates cooling.

It is furthermore advantageous if the shaped light beams of the light sources are directed onto the micromirror array at different angles of incidence.

It is also advisable if the active mirror surface of the micromirror array is subdivided into partial regions which are assigned to the individual light sources.

It may be expedient if each light source is assigned an illumination optical system located between it and the common micromirror array.

On the other hand, it can be provided in the sense of a particularly compact design that two or more light sources are assigned a located between them and the common micromirror array illumination optics.

To achieve a cost-effective and space-saving design further, because the two areas of the single imaging optics are superimposed and formed of a body of optical glass / plastic lens-like.

It may also be advantageous if the lens body is located in the front region of the headlamp and a partial optical system designed as a lens / lens system is arranged between the micromirror array and the lens body.

Another advantageous embodiment is characterized in that one region of the single imaging optics is assigned to one of the multiple light sources, whereas the further region of the imaging optics is assigned to two or more light sources.

• Fig. 1 für die Erfindung wesentliche Komponenten einer ersten Ausführungsform eines Scheinwerfers mit einem Mikrospiegelarray in schematischer Darstellung,
• Fig. 2 eine zweite beispielsweise Ausführungsform der Erfindung in einer perspektivischen vereinfachten Darstellung mit Hervorhebung der für die Erfindung wesentlichen Komponenten,
• Fig. 3 in vergrößerter perspektivischer Ansicht ein erstes Beleuchtungsmodul der Ausführung nach Fig. 2, jedoch aus einem anderen Blickwinkel gesehen,
• Fig.4 in vergrößerter perspektivischer Ansicht ein zweites Beleuchtungsmodul der Ausführung nach Fig. 2, jedoch aus einem anderen Blickwinkel gesehen,
• Fig. 5 eine Vorderansicht eines bei der Erfindung beispielsweise verwendeten DLP-Bauteils mit einem Mikrospiegelarray und
• Fig. 6 eine verkleinerte Seitenansicht der Ausführung nach Fig. 2 zur Veranschaulichung der gegen die Horizontale geneigten optischen Achsen der beiden Beleuchtungsmodule.

The invention together with further advantages is explained in more detail below by way of example embodiments, which are illustrated in the drawing. In this show

• Fig. 1 components of a first embodiment of a headlight with a micromirror array essential for the invention, in a schematic representation,
• Fig. 2 a second example embodiment of the invention in a perspective simplified representation with emphasis on the essential components of the invention,
• Fig. 3 in an enlarged perspective view of a first lighting module of the embodiment according to Fig. 2 but seen from a different angle,
• Figure 4 in an enlarged perspective view of a second lighting module of the embodiment according to Fig. 2 but seen from a different angle,
• Fig. 5 a front view of a DLP device used in the invention, for example, with a micromirror array and
• Fig. 6 a reduced side view of the execution after Fig. 2 to illustrate the inclined against the horizontal optical axes of the two lighting modules.

With reference to Fig. 1 Now, an embodiment of the invention will be explained in more detail. In particular, the important parts for a headlight according to the invention are shown, it being understood that a motor vehicle headlamp contains many other parts that allow its meaningful use in a motor vehicle, in particular a car or motorcycle. Photometric starting point of the headlamp are in the present case, two light sources 1 A and 1B, each emit a light beam 2A, 2B , and which a control 3 is assigned, said control 3 for powering the light sources 1A and 1B and for monitoring or eg Temperature control is used and can also be configured to modulate the intensity of the radiated light beam. By "modulating" in the context of the present invention is meant that the intensity of the light source can be changed, whether continuous or pulsed, in the sense of switching on and off. In addition, there is the possibility of switching on and off for a certain time.

As light sources are not only excited by laser radiation phosphorus elements in question, but it can also classic LEDs or high-current LEDs are used. It can also find so-called "LED packages" use, in addition to a small, for example, 1 to 2 mm ² large light-emitting surface and the substrate on the LED board and their Include support plate. Preferably, LED light sources are used, which can be operated at high currents in order to achieve the highest possible luminous flux on the DMD chip as high as possible. The drive signals of the light sources are designated U _SA and U _SB .

The control 3 in turn receives signals from the central processing unit 4, which sensor signals s ₁ ... si ... s _n can be supplied. On the one hand, these signals may, for example, be switching commands for switching from high beam to low beam or, on the other hand, signals received by sensors, such as cameras, which detect the lighting conditions, environmental conditions and / or objects on the road. Also, the signals may originate from vehicle-vehicle communication information. The arithmetic unit 4 drawn here schematically as a block can be contained completely or partially in the headlight, wherein the arithmetic unit 4 is also assigned a memory unit 5 .

The light sources 1A, 1B is followed by an optics 6A and 6B , the formation of which depends inter alia on the type, number and spatial placement of the lamps used, such as laser diodes or LEDs as well as the required beam quality, and which should primarily ensure that the light emitted by the light source strikes the micromirrors of a micromirror array 7 as homogeneously as possible.

The focused or shaped light beam 2 then passes to this micromirror array 7, on which a light image 8 is formed by corresponding position of the individual micromirrors, which can be projected via an imaging optics 9 as a light image 10 on a roadway 11 or more generally in the traffic area. In this embodiment, the imaging optics 9 has a lens body 9k with two regions 9kA and 9kB , which are arranged one above the other and which are shaped in a lens-like manner from optical glass or plastic. The arithmetic unit 4 supplies signals s _a to an array driver 12, which controls the individual micromirrors of the array 7 in the manner corresponding to the desired light image. The individual micromirrors of the array 7 can be individually controlled with regard to the frequency, the phase and the deflection angle.

In Fig. 1 An absorber 13 already mentioned above is also drawn in, which is generally important for the high quality of the image produced.

The active mirror surface of the micromirror array 7 is divided here into subregions 7A and 7B , which are assigned to the two light sources 1A, 1B. Furthermore, two regions 9A, 9B of the imaging optics 9 are associated with the light bundle reflected by the array 7 or its partial regions 7A, 7B, the light image 10 also being composed of two image regions 10A and 10B as a result.

Now, referring to Fig. 2 an example embodiment of the invention based on a headlight after Fig. 1 described, but with other components essential to the invention, wherein for the explanation of the invention is not essential, in Fig. 1 already shown components are omitted and also other mechanical parts, such as fasteners, housings, cooling devices, power supplies and the like. More.

In detail, one recognizes the first light source 1A with the first illumination optics 6A, to which supplemental to the enlarged view of Fig. 3 is referenced. The first light source 1A has an LED chip 14 with connection contacts 15 and with a light-emitting surface 16 of a high-power LED. The optical axis associated with the light source 1A or the associated illumination optics 6A is designated by the reference numeral 17A .

In contrast to the light source 1A, the light source 1B is composed of three partial light sources 1B -1, 1B-2 and 1B-3. In the present embodiment, each of these partial light sources is structured as well as the light source 1A, so that a more detailed description can be dispensed with. Here and below, the same reference numerals are used for the same or similar parts.

In order to combine the light emitted by the light-emitting surfaces 16 of the three partial light sources 1B-1, 1B-2 and 1B-3 to form a composite light beam 2B having substantially one optical axis 17B , a somewhat more complex illumination optical unit 6B is required for these light sources, here consisting of three partial lenses 6B-1, 6B-2, 6B-3 and from a further, the partial lenses downstream lens 6B-4 , which consists of a light source near lens combination Fig. 4 evident. The illumination optics, which are not shown in detail and as such are not the subject of the invention, are preferably multi-stage optics which capture the Lambertian radiation characteristics and each have to form a light spot 18A, 18B, 18C of suitable geometry on the mirror array 7. In Fig. 4 are schematically indicated such spots.

The array 7 consists of a matrix of micromirrors and is the optically essential area of a DMD component 19. In addition to the micromirror array, such DMD components usually contain subregions of the driver electronics and are equipped with effective cooling. As already mentioned, on the DMD chip very many, for example (Texas Instruments DLP3000DMD) 608x684 micromirrors are arranged on a surface with a diagonal of 7.62 mm, which can waste at + \ - 12 degrees. The drive of the micromirror is usually electrostatic.

The imaging optics 9 is also designed as a multi-stage lens system and has in this variant a located at the front end of the headlight lens body 9k with two areas 9kA and 9kB, which are arranged one above the other and which are shaped like a lens of optical glass or plastic. In general, apart from this lens body 9k of the imaging optics 9, at least one partial optic 9f will also be arranged between the mirror array 7 and the lens body 9k. This sub-optic 9f is also generally designed as a lens which, for example, has different refractive powers in an upper and a lower region 9fA and 9fB .

In the view of Fig. 5 it can be seen that the optically active surface of the mirror array 7, ie the mirror surface 7f, is subdivided into partial regions 7A, 7B-1, 7B-2 and 7B-3 , which, analogously to FIG according to the execution Fig. 1 to which four light sources 1A, 1B-1, 1B-2 and 1B-3 are assigned. Again, the light image generated here is projected by the illumination optics 9 on the road as a corresponding, consisting of four image areas existing photo. This has already been on hand Fig. 1 shown and does not need to be shown again for the skilled person. However, this recognizes that the overall structure, despite the presence of four individual light sources thanks to the invention can be made relatively simple, compact and inexpensive.

The side view of Fig. 6 is to illustrate the position of the optical axes of the above-described embodiment with respect to a horizontal plane ε, whereupon the optical axis 17A of the light source 1A above and the optical axis 17B of the light source 1B composed of the three sub-light sources 1B-1, 1B-2 and 1B-3 are below the drawn horizontal plane ε is located. It should be clear that the terms used "above" and "below" are not limiting, only in connection with the view shown and can for example refer to a normal position of use of a vehicle. The same applies mutatis mutandis to the terms "left", "right", "front", "rear", "sideways" etc ..

List of reference numbers

1A

light source

1B

light source

1B-1

Partial light source

1B-2

Partial light source

1B-3

Partial light source

2A

beam of light

2 B

beam of light

3

control

4

computer unit

5

storage unit

6A

illumination optics

6B

illumination optics

6B-1

partial lens

6B-2

partial lens

6B-3

partial lens

6B-4

lens

7

Micromirror array

7A

Part of 7

7B

Part of 7

7B-1

Part of 7

7B-2

Part of 7

7B-3

Part of 7

7f

mirror surface

8th

Leuchtbild

9

imaging optics

9f

partial optics

9FA

Area

9Fb

Area

9k

lens body

9kA

Range of 9k

9kB

Range of 9k

10

photograph

10A

image area

10B

image area

11

roadway

12

array control

13

absorber

14

LED chip

15

terminals

16

light-emitting surface

17A

optical axis

17B

optical axis

18A

spot

18B

spot

18C

spot

19

DMD component

s ₁ ... s _n

sensor signals

s _a

signals

U _SA

control signal

U _SB

control signal

ε

WL

Claims (8)

1. Headlamp for vehicles having at least one light source (1A, 1B; 1B-1, 1B-2, 1B-3) and an illumination optical system assigned thereto, having a micro-mirror array (7) and an imaging optical system (9, 9f) configured as a lens, wherein the light source and the micro-mirror array are assigned a central computing unit (4) with a light sources control (3) and an array control (12),
   the shaped light beams (2A, 2B) of the at least one light source are directed as the micro-mirror array and the light bundle structured and reflected by said array is projected via the imaging optical system as a light image (10) into the traffic area,
   wherein at least two light sources (1A, 1B; 1B-1, 1B-2, 1B-3) are provided, the light beams whereof are directed at a micro-mirror array (7) common to the light sources and the light bundle reflected by said array is assigned two regions (9kA, 9kB) of an imaging optical system (9, 9f) lying above one another for two image regions of the light image,
   characterized in that
   these regions of the imaging optical system lying above one another have a different refractive power.
2. Headlamp according to claim 1, characterized in that the shaped light beams of the light sources (1A, 1B, 1B-1, 1B-2, 1B-3) are directed at different angles of incidence at the micro-mirror array (7).
3. Headlamp according to claim 1 or 2, characterized in that the active mirror surface (7f) of the micro-mirror array (1) is divided into partial regions which are assigned to the individual light sources.
4. Headlamp according to one of claims 1 to 3, characterized in that each light source (1A, 1B) is assigned a lighting optical system (6A, 6B) which lies between said light source and the common micro-mirror array (7).
5. Headlamp according to one of claims 1 to 3, characterized in that the two or more light sources (1B-1, 1B-2, 1B-3) are assigned a lighting optical system (6B) lying between said light sources and the common micro-mirror array (7).
6. Headlamp according to one of claims 1 to 5, characterized in that the two regions (9kA, 9kB) of the imaging optical system (9) are formed as a lens from a lens body (9k) from optical glass/plastic.
7. Headlamp according to one of claims 1 to 6, characterized in that the lens body (9k) lies in the front region of the headlamp and a partial optical system (9f) configured as a lens/lens system is arranged between the micro-mirror array (7) and the lens body
8. Headlamp according to one of claims 1 to 7, characterized in that a region (9kA) of the imaging optical system (9) is assigned to one (1A) or multiple light sources, whereas the other region (9kB) of the imaging optical system is assigned two or more light sources (1B-1, 1B-2, 1B-3).

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