EP3420269A1 - Headlight for vehicles - Google Patents

Abstract

A headlight for vehicles, having at least one light source (1A, 1B) and lighting optics which are assigned thereto and have a micromirror array (7) and imaging optics (9), wherein the light source and the micromirror array are assigned a central computing unit (4) with a light source actuation means (3) and an array actuation means (12), the shaped light beams (2A, 2B) of the at least one light source are directed onto the micromirror array and the reflected composite light beam which is structured by said micromirror array is projected into the traffic space as a light pattern (10) via the imaging optics, wherein at least two light sources (1A, 1B) are provided, the light beams of which are directed onto a micromirror array (7) which is common to the light sources, and the composite light beam which is reflected by said micromirror array (7) is assigned at least two regions (9kA, 9kB) of imaging optics (9).

Description

 Headlights for vehicles

 The invention relates to a headlamp for vehicles, having at least one light source and one of these associated illumination optics, with a micromirror array and 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, the molded Light beams of the at least one light source are directed to the micromirror array and the structured by this, reflected light beam is projected via the imaging optics as a light image in the traffic area.

 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 can 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 "carriageway" is used here for a simplified representation, because of course it depends on the local conditions, whether a photo is actually on the roadway or extends beyond it.In principle, the photograph in the sense used here corresponds to a projection on a vertical Area according to the relevant standards, which relate to the automotive lighting technology.

 According to the mentioned need different headlight systems have been developed, such as in particular with scanning, modulated laser beam working headlamps, wherein lighting starting point at least one

Laser light source, which emits a laser beam, and which is associated with a laser driver, which is used for power supply and for monitoring the laser emission or e.g. for temperature control and also for modulating the intensity of the

radiated laser beam is set up. 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 driving concept for forming an image by a scanning laser beam is described, for example, in Applicant's document AT 514633.

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 in terms of the generated photo, headlights are also known become, which use as Lichtbearbeitungselemente imagers, which have a large number of controllable pixel fields. For example, DE 10 2013 215 374 A1 shows solutions in which the light from a light source is directed via a light-guiding element to an LCD imager to form an LCoS chip or a micromirror arrangement ("DMD") and then onto the road via projection optics to be projected.

 DMD is an acronym used for "Digital Micromirror Device", thus for a micromirror array or micromirror array Such a micromirror array has very small dimensions, typically on the order of 10 mm. In a DMD, micromirror actuators are matrix-like arranged, each individual mirror element, which has, for example, an edge length of about 16 μιη, 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 rays that emanate from micromirrors in their non-"active" angular position and that are not projected onto the road via the imaging optics, using absorbers or absorber surfaces which are otherwise harmful

Absorb 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 is the Micro Electro Mechanical Systems (MEMS) technology.

 While the DMD technology has two stable mirror states and the reflections can be adjusted by modulating between the two stable states, 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 described for example in DE 195 30 008 AI.

 In headlamps of motor vehicles one wants to realize in a 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 performed not only on the modulation of the primary light source but also on different array controls for different light distributions, such as high beam, low beam with or without asymmetry, skimming scenarios, etc., with different array controls the individual

Activate micromirror elements depending on 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 according to the invention at least two light sources are provided, the light beams are directed to a light sources common micromirror array and the light beam from this reflected at least two areas of a single imaging optics are assigned.

 Thanks to the invention, several light functions can be combined with a single one

Micro mirror array and a single imaging optics are realized, which the

Overall construction simplified and cheaper. 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 useful if each light source between this and the

associated with common micromirror array located illumination optics.

 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.

 For a cost-effective and space-saving design one arrives further, if 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 headlight and between the micromirror array and the lens body as a

Lens / lens system formed partial optics is arranged.

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

 The invention together with further advantages is below by way of example

Embodiments explained in more detail, which are illustrated in the drawing. In this show

 1 for the invention essential components of a first embodiment of a headlamp with a micromirror array in a schematic representation,

 Fig. 2 shows a second example embodiment of the invention in a perspective simplified representation with emphasis on the essential for the invention

components 3 is an enlarged perspective view of a first illumination module of the embodiment of FIG. 2, but seen from a different angle,

 4 shows an enlarged perspective view of a second lighting module of

Embodiment of FIG. 2, but seen from a different angle,

 Fig. 5 is a front view of a DLP device used in the invention, for example, with a micromirror array and

 Fig. 6 is a reduced side view of the embodiment of FIG. 2 for illustrating the inclined against the horizontal optical axes of the two lighting modules.

 With reference to Fig. 1, an embodiment of the invention will now 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. Lichttechnischer starting point of the headlamp are in the present case, two light sources 1A and 1B, each emit a light beam 2A, 2B, and which is associated with a control 3, wherein this control 3 for

Power supply of the light sources 1A and 1B and for monitoring thereof or e.g. serves for temperature control 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 is also possible to use so-called "LED packages" which, in addition to a small, eg 1 to 2 mm ^2, light-emitting area, also comprise the substrate on the LED board and its carrier plate can be operated at high currents in order to achieve the highest possible luminance on the DMD chip at as high a luminous flux as possible.The drive signals of the light sources are designated US and USB.

The control 3 in turn receives signals from the central processing unit 4, which sensor signals si ... 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 record the lighting conditions, environmental conditions and / or objects on the road. Also, the signals may originate from vehicle-vehicle communication information. The here schematically drawn as a block

Computing unit 4 may be completely or partially contained in the headlight, 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 the spatial placement of the lamps used, such as laser diodes or LEDs as well as the required beam quality, and which Above all, it should ensure that the light emitted by the light source hits 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 computing unit 4 provides signals s _a to an array driver 12, which the individual micromirrors of the array 7 in the desired light image

corresponding manner drives. The individual micromirrors of the array 7 can be individually controlled with regard to the frequency, the phase and the deflection angle.

FIG. 1 also shows an absorber 13 already mentioned above, which is generally important for a high quality of the image produced.

 The active mirror surface of the micromirror array 7 is here in partial regions 7A and 7B

split, which are the two light sources 1A, 1B assigned. 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.

 Referring now to Fig. 2, an example embodiment of the invention based on a headlamp according to Fig. 1 will be described, but with further examples

Components essential to the invention are omitted, for the explanation of the invention not essential, already shown in FIG. 1 components 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 reference is additionally made to the enlarged view of FIG. 3. 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 into a composite light beam 2B having substantially one optical axis 17B, a somewhat more elaborate one of these light sources Illumination optics 6B required, which here consists of a light source near lens combination, consisting of three partial lenses 6B-1, 6B-2, 6B-3 and another, the partial lenses downstream lens 6B-4, which is apparent from Fig. 4. 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 to a light spot 18A, 18B, 18C of suitable geometry on the

Mirror array 7 must form. In Fig. 4 schematically such spots are indicated.

The array 7 consists of a matrix of micromirrors and is the optically essential portion of a DMD device 19. Such DMD devices include the

Micro mirror array usually parts of the driver electronics and are with a

equipped with effective cooling, as already mentioned, are on the DMD chip very many, for example (Texas Instruments DLP3000DMD) 608x684 micromirror arranged on a surface with a diagonal of 7.62 mm, which can waste around + \ - 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, i. the mirror surface 7f, is divided into sections 7A, 7B-1, 7B-2 and 7B-3, which, analogous to the embodiment of FIG. 1, the four light sources 1A, 1B-1, 1B-2 and 1B-3 assigned are. 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 shown with reference to FIG. 1 and does not have to be represented again for the person skilled in the art. 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 intended 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 three partial light sources 1B-1, 1B-2 and 1B -3 composite light source 1B is below the plotted horizontal plane ε. It should be clear that the terms used "above" and "below" are not limiting, only in connection with the view shown and are, for example, a normal

Can relate to the operating position 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 light beam

2B light beam

3 control

4 arithmetic 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 subarea of 7

7B section of 7

7B-1 subsection of 7

7B-2 subsection of 7

7B-3 subsection of 7

7f mirror surface

8 light picture

9 imaging optics

9f partial optics

9fA range

 9fB range

9k lens body 9kA range of 9k

9kB range of 9k

10 photograph

 10A image area

 10B image area

 11 lane

 12 array control

13 absorbers

 14 LED chip

 15 connection contacts

16 light-emitting surface

17A optical axis

17B optical axis

18A light spot

 18B light spot

 18C light spot

 19 DM D component

Sl ... S _n sensor signals

 Sa signals

 USA drive signal

USB control signal ε horizontal plane

Claims

claims A headlamp for vehicles, comprising at least one light source (1A, 1B, 1B-1, 1B-2, 1B-3) and one of these associated illumination optics, with a micromirror array (7) and with imaging optics (9, 9f) the light source and the micromirror array, a central processing unit (4) with a light source drive (3) and a Array drive (12) is assigned, the shaped light beams (2A, 2B) of the at least one light source on the Micro mirror array are directed and projected by this, reflected light beam on the imaging optics as a light image (10) is projected into the traffic space, characterized in that at least two light sources (1A, 1B, 1B-1, 1B-2, 1B-3) are provided whose light beams are directed to a micromirror array (7) common to the light sources and at least two areas (9kA, 9kB) to the light bundle reflected thereby an imaging optics (9, 9f) are assigned.  2. Headlight 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 on the micromirror array (7).  3. Headlight according to claim 1 or 2, characterized in that the active Mirror surface (7f) of the micromirror array (7) is divided into subregions, which are assigned to the individual light sources.  4. Headlight according to one of claims 1 to 3, characterized in that each light source (1A, 1B) is assigned a between this and the common micromirror array (7) located illumination optics (6A, 6B).  5. Headlight according to one of claims 1 to 3, characterized in that two or more light sources (1B-1, 1B-2, 1B-3) is assigned a between these and the common micromirror array (7) located illumination optics (6B).  6. Headlight according to one of claims 1 to 5, characterized in that the two areas (9kA, 9kB) of the imaging optics (9) one above the other and from a Lensenkörper (9k) of optical glass / plastic lens-like design.  7. Headlight according to one of claims 1 to 6, characterized in that the lens body (9k) is located in the front region of the headlamp and between the micromirror array (7) and the lens body designed as a lens / lens system sub-optics (9f) is arranged. 8. Headlight according to one of claims 1 to 7, characterized in that a region (9kA) of the imaging optics (9) one (1A) of the plurality of light sources is assigned, whereas another area (9kB) of the imaging optics two or more light sources (1B -1, 1B-2, 1B-3).