Headlight for vehicles

Abstract

A headlight for vehicles including at least one light source and an illumination optics system associated therewith, comprising a micromirror array and a projection optics system. A central processing unit comprising a light source control unit and an array control unit is associated with the light source and the micromirror array. The shaped rays of light of the light source are directed at the micromirror array, and the reflected light beam structured thereby is projected by the projection optics system as a light image into a traffic space. At least two light sources are provided, the rays of light of which are directed at a micromirror array common to the light sources, and at least two superimposed regions of a projection optics system having different refractive powers for at least two image regions of the light image are associated with the light beam reflected by the micromirror array.

Claims

1. A headlight for vehicles, comprising: at least two light sources (1A, 1B; 1B-1, 1B-2, 1B-3); and an illumination optics system associated with one of the at least two light sources, the illumination optics system comprising a micromirror array (7) and a projection optics system (9, 9f) comprising a lens, a central processing unit (4) comprising a light source control unit (3) and an array control unit (12) associated with the at least two light sources and the micromirror array, wherein the illumination optics system is configured to direct shaped rays of light (2A, 2B) of one of the at least two light sources at the micromirror array, and wherein a reflected light beam is projected by the projection optics system as a light image (10) into a traffic space, wherein rays of light from the at least two light sources are directed at the micromirror array (7) that is common to the at least two light sources, and wherein at least two superimposed regions (9kA, 9kB) of the projection optics system (9, 9f), which have different refractive powers for at least two image regions of the light image are associated with the reflected light beam, and wherein the rays of light of the at least two light sources (1A, 1B; 1B-1, 1B-2, 1B-3) are directed at the micromirror array (7) at varying angles of incidence.

2. The headlight according to claim 1, wherein an active mirror surface (7f) of the micromirror array (7) is divided into sub-regions, which are associated with individual light sources of the at least two light sources.

3. The headlight according to claim 1, wherein one light source (1A, 1B) of the at least two light sources is associated with the illumination optics system (6A, 6B) located between the at least two light sources and the micromirror array (7).

4. The headlight according to claim 1, wherein two or more light source (1B-1, 1B-2, 1B-3) of the at least two light sources are associated with the illumination optics system (6B) located between the at least two light sources and the micromirror array (7).

5. The headlight according to claim 1, wherein the at least two superimposed regions (9kA, 9kB) of the projection optics system (9) are superimposed and designed in a lens-like manner from a lens body (9k) made of optical glass/plastic material.

6. The headlight according claim 5, wherein the lens body (9k) is located in a front region of the headlight, and a sub-optics system (9f) comprising a lens is arranged between the micromirror array (7) and the lens body.

7. The headlight according to claim 1, wherein one region (9kA) of the projection optics system (9) is associated with one (1A) of the at least two light sources, while another region (9kB) of the projection optics system is associated with two or more light sources (1B-1, 1B-2, 1B-3) of the at least two light sources.

Description

(1) The invention, along with further advantages, will be described in greater detail hereafter based on exemplary embodiments, which are illustrated in the drawings. In the drawings:

(2) FIG. 1 shows components of a first embodiment of a headlight that are essential to the invention, comprising a micromirror array, in a schematic illustration;

(3) FIG. 2 shows a second exemplary embodiment of the invention in a perspective simplified illustration, highlighting the components that are essential to the invention;

(4) FIG. 3 shows an enlarged perspective view of a first illumination module of the embodiment according to FIG. 2, but seen from a different viewing angle;

(5) FIG. 4 an enlarged perspective view of a second illumination module of the embodiment according to FIG. 2, but seen from a different viewing angle;

(6) FIG. 5 shows a front view of a DLP component used by way of example in the invention, comprising a micromirror array; and

(7) FIG. 6 shows a smaller side view of the embodiment according to FIG. 2 to illustrate the optical axes of the two illumination modules inclined with respect to the horizontal.

(8) Referencing FIG. 1, one exemplary embodiment of the invention will now be described in greater detail. In particular, the parts important for a headlight according to the invention are shown, wherein it is clear that a motor vehicle headlight also contains a number of other parts that allow meaningful use of the headlight in a motor vehicle, such as in particular a passenger car or motorcycle. The lighting-related starting point of the headlight in the present case is two light sources 1A and 1B, which each emit a ray of light 2A, 2B and which are associated with a control unit 3, wherein this control unit 3 is used for power supply purposes of the light sources 1A and 1B and for monitoring these or, for example, for controlling the temperature, and can also be configured to modulate the intensity of the emitted ray of light. Modulating in the context of the present invention is understood to mean that the intensity of the light source can be altered, either continuously or in a pulsed manner, within the meaning of switching on and off. Additionally, there is also the option of switching on and off for a certain period of time.

(9) Possible light sources include not only phosphor elements excited by laser radiation, but it is also possible to use traditional LEDs or high-current LEDs. It is also possible to use what are known as LED packages, which in addition to a small light-emitting surface area, measuring 1 to 2 mm.sup.2, for example, also include the substrate on the LED board and the support plate thereof. Preferably, LED light sources are used that can be operated with high currents, so as to achieve as high a luminance as possible on the DMD chip, at the lowest possible luminous flux. The control signals of the light sources are denoted by U.sub.SA and U.sub.SB.

(10) The control unit 3, in turn, receives signals from the central processing unit 4, which to which sensor signals s.sub.1 . . . si . . . s.sub.n can be supplied. These signals can be switching commands for switching from high-beam light to low-beam light, for example, or signals recorded, for example, by sensors, such as cameras, which pick up the lighting conditions, environmental conditions and/or objects on the roadway. The signals can also stem from vehicle-to-vehicle communication information. The processing unit 4 shown here schematically in the form of a block can be included entirely or partially in the headlight, wherein a memory unit 5 is also associated with the processing unit 4.

(11) An optics system 6A or 6B is arranged downstream of the light sources 1A, 1B, the embodiment of which depends, among other things, on the type, number and spatial arrangement of the luminous elements used, such as laser diodes or LEDS, and the required beam quality, and which, above all, is intended to ensure that the light emitted by the light source impinges upon the micromirrors of a micromirror array 7 as homogeneously as possible.

(12) The focused or shaped ray of light 2 arrives at this micromirror array 7 on which, by way of an appropriate position of the individual micromirrors, a luminous image 8 is formed, which can be projected by way of a projection optics system 9 in the form of a light image 10 onto a roadway 11 or, generally speaking, into the traffic space. In this embodiment, the projection optics system 9 comprises a lens body 9k including two regions 9kA and 9kB, which are arranged on top of one another here and together are shaped in a lens-like manner, made of optical glass or plastic material. The processing unit 4 supplies signals s.sub.a to an array control unit 12, which controls the individual micromirrors of the array 7 in the appropriate manner for the desired light image. The individual micromirrors of the array 7 can be individually controlled in terms of the frequency, the phase and the deflection angle.

(13) FIG. 1 also depicts an absorber 13, which was already mentioned above and generally is important for a high quality of the generated image.

(14) The active mirror surface of the micromirror array 7 is divided into sub-regions 7A and 7B here, which are associated with the two light sources 1A, 1B. Furthermore, the light beam reflected by the array 7, or by the sub-regions 7A, 7B thereof, are associated with two regions 9A, 9B of the projection optics system 9, wherein consequently the light image 10 is also composed of two image regions 10A and 10B.

(15) Referencing FIG. 2, an exemplary embodiment of the invention will be described hereafter based on a headlight according to FIG. 1, however comprising further components that are essential to the invention, wherein components that are not essential for the description of the invention and were already shown in FIG. 1 have been omitted, as were other mechanical parts, such as fastening means, housings, cooling units, power supply units and the like.

(16) In detail, the first light source 1A comprising the first illumination optics system 6A is apparent, for which additionally reference is made to the enlarged illustration in FIG. 3. The first light source 1A comprises an LED chip 14 including connecting contacts 15 and a light-emitting surface 16 of a high performance LED. The optical axis associated with the light source 1A, or with the associated illumination optics system 6A, is denoted by reference numeral 17A.

(17) In contrast to the light source 1A, the light source 1B is composed of three light sub-sources 1B-1, 1B-2 and 1B-3. In the present exemplary embodiment, each of these light sub-sources is designed in the same manner as the light source 1A, so that a more detailed description can be dispensed with. Identical reference numerals are used here and hereafter for identical or comparable parts.

(18) To combine the light of the three light sub-sources 1B-1, 1B-2 and 1B-3 emitted by the light-emitting surfaces 16 so as to form an assembled ray of light 2B having essentially an optical axis 17B, a slightly more complex illumination optics system 6B is required for these light sources, which here is composed of a lens combination located close to the light source, composed of three sub-lenses 6B-1, 6B-2, 6B-3 and a further lens 6B-4 arranged downstream of the sub-lenses, as is apparent from FIG. 4. The illumination optics systems, which are not shown in detail and, per se, are not the subject matter of the invention, are preferably multi-stage optics system, which must collect the Lambert's emission characteristics and shape these into a respective luminous spot 18A, 18B, 18C having a suitable geometry on the mirror array 7. FIG. 4 schematically indicates such luminous spots.

(19) The array 7 is composed of a matrix of micromirrors and represents the optically significant region of a DMD component 19. In addition to the micromirror array, such DMD components usually include sub-regions of the driver electronics and are equipped with an effective cooling system. As was already mentioned at the outset, a large number of, for example (Texas Instruments DLP3000DMD) 608684, micromirrors are arranged on the DMD chip on a surface area having a diagonal of 7.62 mm, which can be pivoted by +/12 degrees. The micromirror is usually driven electrostatically.

(20) The projection optics system 9 is also designed as a multi-stage lens system and, in this variant, comprises a lens body 9k that is located at the front end of the headlight and includes two regions 9kA and 9kB, which are arranged on top of one another here and together are shaped in a lens-like manner, made of optical glass or plastic material. In general, at least one sub-optics system 9f will be arranged between the mirror array 7 and the lens body 9k, in addition to this lens body 9k of the projection optics system 9. This sub-optics system 9f is also generally designed in the form of a lens, which has different refractive powers in an upper and a lower region 9fA and 9fB, for example.

(21) In the view shown in FIG. 5, it is apparent that the optically active surface area of the mirror array 7, which is to say the mirror surface 7f, is divided into sub-regions 7A, 7B-1, 7B-2 and 7B-3, which, analogously to the embodiment according to FIG. 1, are associated with the four light sources 1A, 1B-1, 1B-2 and 1B-3. Again, the luminous image generated here is projected by the illumination optics system 9 onto the roadway as a corresponding light image, which is composed of four image regions here. This was already shown based on FIG. 1 and does not require explanation again for a person skilled in the art. The skilled practitioner, however, will recognize that the overall design, despite the presence of four individual light sources, can have a relatively simple, compact and cost-effective design thanks to the invention.

(22) The side view of FIG. 6 is intended to illustrate the positions of the optical axes of the above-described exemplary embodiment with respect to a horizontal plane c, according to which the optical axis 17A of the light source 1A is located above, and the optical axis 17B of the light source 1B composed of the three light sub-sources 1B-1, 1B-2 and 1B-3 is located beneath, the plotted horizontal planes. It should be clear that the terms above and beneath are not limiting to the invention, but shall only be understood in connection with the shown view and can refer, for example, to a normal usage position of a vehicle. The same applies analogously to the terms left, right, front, rear, laterally and the like.

LIST OF REFERENCE SIGNS

(23) 1A light source 1B light source 1B-1 light sub-source 1B-2 light sub-source 1B-3 light sub-source 2A ray of light 2B ray of light 3 control unit 4 processing unit 5 memory unit 6A illumination optics system 6B illumination optics system 6B-1 sub-lens 6B-2 sub-lens 6B-3 sub-lens 6B-4 lens 7 micromirror array 7A sub-region of 7 7B sub-region of 7 7B-1 sub-region of 7 7B-2 sub-region of 7 7B-3 sub-region of 7 7f mirror surface 8 luminous image 9 projection optics system 9f sub-optics system 9fA region 9fB region 9k lens body 9kA region of 9k 9kB region of 9k 10 light image 10A image region 10B image region 11 roadway 12 array control unit 13 absorber 14 LED chip 15 connecting contacts 16 light-emitting surface 17A optical axis 17B optical axis 18A luminous spot 18B luminous spot 18C luminous spot 19 DMD component s.sub.1 . . . s.sub.n sensor signals s.sub.a signals U.sub.SA control signal U.sub.SB control signal horizontal plane