AT519595B1 - Method and device for generating a light distribution in front of a vehicle - Google Patents

Abstract

Method (1000) for generating a light distribution in front of a vehicle, wherein the following method steps are carried out: - generating (1010) a light beam through at least one light source, - emitting (1020) the light beam in the direction of an optoelectronic device, - selecting (1030) an in light distribution stored in a data memory, - acquiring (1040) an ambient temperature to a temperature parameter, and / or a precipitation to a precipitation intensity parameter and / or a precipitation parameter, - determining (1050) the temperature, precipitation intensity, precipitation parameter as at least one parameter, Defining (1060) an overlay function from the at least one parameter; overlaying (1070) the light distribution with the overlay function into a light matrix, driving the optoelectronic component through the light matrix by means of the output unit, modulating (1090) irradiated light beam through the optoelectronic component and at least partially reflecting the light beam in the direction of at least one projection optics, - projecting (1100) of the modulated light beam through the at least one projection optics and forming a light image in front of the vehicle.

Description

description

METHOD FOR PRODUCING A LIGHT DISTRIBUTION BEFORE A VEHICLE

The invention relates to a method for generating a light distribution in front of a vehicle.

In addition, the invention relates to a device for generating a light distribution in front of a vehicle, in particular a vehicle headlight, in which the method steps according to the invention are executable.

Furthermore, the invention relates to an assembly for generating a light distribution in front of a vehicle, in particular a vehicle headlamp, in which the method steps according to the invention are executable.

In the development of the current headlamp systems is increasingly the desire in the foreground to be able to project a high-resolution as possible light image on the road, which can be changed quickly 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 is used in the sense used here on the basis of a projection on a vertical surface according to the relevant standards, which relate to the automotive lighting technology defined. Furthermore, the generated light image should be adaptable to different traffic situations.

Among other things, headlamps have been developed in which a variably controllable reflector surface is formed from a plurality of micromirrors and on selected areas a light emission, which is generated by a light source unit, reflected in the emission direction of the headlamp. Such lighting devices are advantageous in vehicle because of their very flexible lighting functions, since the illumination intensity can be controlled individually for different lighting areas and any light functions can be realized with different light distributions, such as a low beam light distribution, a cornering light distribution, a city light distribution, a Highway light distribution, cornering light distribution, high beam distribution, auxiliary high beam distribution, or the formation of glare-free high beam (also known as Adaptive Driving Beam Headlighting System, ADB).

For the micromirror arrangement, the so-called digital light processing (DLP®) projection technology is used, in which images are generated in that a digital image is modulated onto a light beam. In this case, the light beam is divided into partial areas by a rectangular arrangement of movable micromirrors, also referred to as pixels, and then reflected pixelwise, either into the projection path or out of the projection path. The basis for this technique is an electronic component that contains an array of mirrors in the form of a matrix of mirrors and their driving technique and is referred to as "Digital Micromirror Device" (DMD). A DMD microsystem is a spatial light modulator (SLM) which consists of matrix-shaped micromirror actuators, that is to say tiltable reflecting surfaces, for example with an edge length of approximately 16 μm or even below. The mirror surfaces are designed to be movable by the action of electrostatic fields. Each micromirror is individually adjustable in its tilt angle and usually has two stable end states, between which can be changed within a second up to 5000 times. The individual micromirrors can each be controlled, for example, by a pulse width modulation (PWM) in order to image further states of the micromirrors in the main beam direction of the DMD arrangement whose time-averaged reflectivity lies between the two stable states of the DMD. 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 adjustable mirrors is Micro-Electro-Mechanical Systems (MEMS) technology.

While the DMD technology has two stable mirror states, and by modulation between both stable states, the reflection factor can be set, the "Analog Micromirror Device" (AMD) technology has the property that the individual mirrors are set in variable mirror positions can be, which are there in a stable state.

EP 1 433 655 A2 shows a headlight for motor vehicles with a light source, a micromirror arrangement and a projection optics, as well as a controller and a plurality of sensors. The controller controls different light distributions depending on environmental conditions detected by the sensors.

US 2002196636 A1 and EP 2 965 946 A2 likewise each show headlights for motor vehicles with a light source, a micromirror arrangement and a projection optical unit, which can generate different light distributions as a function of environmental conditions by a corresponding control of the micromirror arrangement.

In a first aspect, when driving with a vehicle, adverse effects may occur due to the influence of the weather, in that emitted headlight light in the area directly in front of the vehicle is reflected back to precipitation, such as raindrops or snowflakes, in the direction of the driver of the vehicle and can lead to visual irritation of the eye, which can lead to fatigue and even dazzling the driver.

A solution to reduce this interfering effect is described in "Programmable Automotive Headlights", R. Tamburo, E. Nurvitadhi, A. Chugh, M. Chen, A. Rowe, T. Kanade and SG Narasimhan, European Conference of Computer Vision (ECCV), 2014, or "Fast Reactive Illumination" by Rain and Snow, R. de Charette, R. Tamburo, P. Barnum, A. Rowe, T. Kanade and SG Narasimhan, IEEE International Conference on Computational Photography (ICCP ), April 2012. The technically complex and sophisticated solutions is in each case a considerable effort in the realization of complex calculation methods and the required for this powerful computer hardware, which can lead to very high costs for development, production, installation and maintenance, additional high space requirements within the vehicle may lead to a higher vehicle weight and, moreover, may have a negative impact on fuel or energy consumption.

In a second aspect, headlamps based on the DMD technology can have a limited lifetime, which is often associated with high temperature sensitivity of the DMD technology.

It is an object of the invention to overcome the disadvantages mentioned.

[0015] The object is achieved by a method of the type mentioned at the outset by carrying out the following method steps: generating a light beam through at least one light source, emitting the light beam in the direction of an optoelectronic component, comprising a controllable arrangement comprising a plurality of individually adjustable optoelectronic elements in the form of a two-dimensional matrix, selecting a light distribution stored in a data memory by means of a selection unit and retrieving the light distribution from the data memory, detecting an ambient temperature to one Temperature parameters, and / or [0021] - a precipitation to a precipitation intensity parameter and / or a precipitation size parameter, - determining the temperature, precipitation intensity, precipitation parameter as at least one parameter, - defining a superposition function on from the at least one parameter, superposition of the light distribution with the superimposition function into a light matrix, activation of the optoelectronic component by the light matrix by means of the output unit, preferably after conversion of the light matrix into a corresponding video signal, [0026] FIG ] - modulating the irradiated light beam through the optoelectronic component, and at least partially reflecting the light beam in the direction of at least one projection optics, - projecting the modulated light beam through the at least one projection optics, and forming a light image in front of the vehicle.

The inventive method ensures that when driving with a vehicle when using vehicle headlamps under the influence of weather, a better visual impression for the driver of the vehicle occurs. In other words, eye fatigue or dazzling of the driver can be significantly reduced by reflecting significantly less emitted headlight in the area immediately in front of the vehicle to precipitation, such as raindrops or snowflakes, back towards the driver of the vehicle. Compared to the prior art, we achieved this under considerably less effort than previously known. Consequently, there are great advantages in terms of development, production, assembly and maintenance costs.

In addition, the space required within the vehicle and the vehicle weight can be reduced, which can have beneficial effects on the fuel or energy consumption of the motor vehicle.

It is favorable if, during the detection, a vehicle speed is also detected to a speed parameter, which is taken into account when determining the at least one parameter.

It is also favorable, when defining a superimposition function also a duty cycle for the control and modulation of the mirror of the optoelectronic device is taken into account.

In a further aspect, at too high an average operating temperature, single or multiple micromirror failures may occur. An effect that occurs in this context is the so-called Hinge Memory Effect (HME), which adversely affects the lifetime of a DMD device 1234. Table 1 shows the influence of duty cycle and 1 M.R. Douglass, "Lifetime Estimates and Unique Failure Mechanisms of the Digital Micromirror Device (DMD)", 36th Annual International Reliability Physics Symposium, Reno, Nevada (1998) 2 A.B. Sontheimer, "Digital Micromirror Device (DMD) Hinge Memory Lifetime Reliability Modeling", 40th Annual International Reliability Physics Symposium, Dallas, Texas (2002) 3 A.B. Sontheimer, "Effects of Operating Conditions on DMD Hinge Memory Lifetime," 41st Annual International Reliability Physics Symposium, Dallas, Texas (2003) 4 S.J. Jacobs et al., "Hermicity and Stiction in MEMS Packaging," 40th Annual International Reliability Physics Symposium, Dallas, Texas (2002)

Operating temperature on the life, which is affected by the HME. It can be seen that temperatures above about 70 ° C should be avoided and the duty cycle should be chosen accordingly.

In Table 1, the following terms are used for certain ranges of the average life of a DMD component, which is determined by the HME:

Very long:> 4,000 hours

Long: 2,001 - 4,000 hours

Medium: 1,000 - 2,000 hours

Short: <1.000 hours For temperatures T1 - T9 the following relationship exists: T1 - T9 [° C]: T1 <T2 <T3 <T4 <T5 <70 ° C <T6 <T7 <T8 <T9

Hinge Memory Effect (HME) The HME is dependent on the duty cycle of the micromirrors, the duty cycle being defined by Equations 1 and 2. The duty cycle is the ratio of switched on to off, that is, between a first micromirror position and a second micromirror position. (Equation 1) (Equation 2)

where f ... switching frequency of the micromirror, h ... image height, hp ... pixel height, pv ... number of pixels in the vertical direction, ... velocity of the interfering object (precipitation element).

Especially when using DMD components in the automotive environment, a DMD component can be strongly heated by very strong and bright light sources and / or by high ambient temperatures. It is advantageous in the design of a cooling concept to consider the duty cycle of the DMD component. As a result, headlamps which use the method according to the invention can have a significantly longer service life.

It is particularly advantageous if the method is further developed by superimposing the light distribution with the overlay function to the light matrix by associating each element of the overlay function with an element of the light distribution and transforming them by a transfer function, wherein the transfer function preferably corresponds to an operation of multiplication or addition. As a result, the overlay function can be realized in a particularly simple and cost-effective manner. There is no need for complex calculations requiring, for example, a floating-point arithmetic unit that would unnecessarily increase system complexity and cost. Basically, as a transfer function, a more complex operation or function is possible, wherein the overlay function comprises a function inverse or complementary to the transfer function to modify, that is to reduce, eliminate or in the light matrix certain areas in their respective amount when performing the operation in the light matrix to increase. In addition, matrix filters known from image processing can also be used in order, for example, to make certain details in the light matrix more pronounced or sharper. In this context, two elements associated with one another are in each case an element of an overlay function, and in each case one element of a light distribution, which are both located at the same location, for example the same pixel in a light matrix.

According to the invention, the number of those elements of the light matrix whose values are essentially zero after the transformation is between 30% and 70%, preferably between 40% and 60%, particularly preferably between 45% and 55% of the total number of elements light matrix. This choice ensures that the desired illumination by a corresponding headlamp meets the lighting requirements for the ride, and also a significant portion of precipitation elements is not illuminated, whereby unwanted reflections can be reduced.

According to the invention, the values of the elements of the light matrix which are substantially nonzero after the transformation are each greater in their magnitude than the amounts of the associated values in the light distribution. It is thereby achieved that the overall illumination, that is to say the average value of the luminous pixels and the non-luminous pixels, emits the same average brightness by a headlight according to the invention at a defined reference distance as a conventional headlight. The value of the respective element is substantially zero if it is significantly below the original brightness reference value of the same element, namely that of full-surface illumination. In other words, the value is analogously zero, for example, if it is 50% or even 10% below the brightness reference value.

Between the number of those elements of the light matrix whose values are substantially zero after the transformation and the duty cycle is a relationship in that all elements over the time and radiating surface in the average (measured in a plane transverse to the direction of illumination of the vehicle headlight in a distance within the field of vision in front of the vehicle, preferably in a range between 1 m and 5 m in front of the vehicle, particularly preferably in a range between 1 m and 50 m in front of the vehicle) should produce the same brightness as a conventional headlamp.

It is particularly advantageous if the overlay function comprises a static projection pattern. This results in a particularly simple and particularly cost-effective implementation possibility. In this case, the static projection pattern may preferably have a strip-shaped pattern, which is vertically oriented in rows, columns horizontally or obliquely as a projected light image of a light distribution in front of the vehicle, or a checkerboard-like pattern or a uniformly distributed random pattern.

The pattern size of the projection pattern is dimensioned such that it corresponds, for example, the average size of the precipitation elements in a viewing distance in front of the vehicle. Usually, the viewing distance of the precipitation elements, in which disturbing optical reflections occur, in about 1 m to 10 m.

Since precipitation elements statistically appear approximately equally distributed in appearance, it is advantageous if the projection pattern is also uniformly distributed. A uniform projection pattern is, for example, a checkerboard pattern in which the horizontal and vertical sections or patterns repeat approximately at equal intervals.

It is favorable if the determination of the overlay function comprises at least one prediction function which comprises a trajectory of a predicted trajectory of a hypothetical, falling precipitation element in the field of vision in front of the vehicle. In this case, the trajectory is calculated from the parameter and the trajectory is defined in each of its function values along its course in each case by a course vector. If the determination of the projection pattern, that is to say the overlay function, is based on the trajectories or trajectories of individual or several precipitation elements, a particularly favorable optical effect on the driver's human eye is achieved.

In one embodiment of the invention, it proves to be particularly advantageous if a time-dependent modulation function, which is defined by a modulation source, is determined along the trajectory. Time intervals determine the repetition rate of the modulation function and the abscissa of the modulation function extends locally along the trajectory. Preferably, this is superimposed by pointwise multiplication and thereby the overlay function is formed in the form of a light modulation function. As a result according to the invention, a very pleasant visual impression of the method is achieved for the observer, in that a possible stroboscopic effect can be reduced. This effect can occur when moving objects are pulsed in time and when the pulse sequence has such a long period of time that the human eye can perceive it. In addition, the stroboscopic effect can be further reduced by making the transitions between the extreme values of the modulation function not discrete, but more or less gentle. In any case, care should be taken that the switching frequency of the micromirrors is chosen to be sufficiently large to allow the human eye as little as possible to be fatigued by a possible flicker effect of the projected light image.

To further improve the visual impression on the viewer, it is advantageous if in the superposition of the overlay function with the light distribution of the magnitude of a function value of the light modulation function at a first location of the trajectory at a first time, the amount of a function value of the light modulation function on a second location of the trajectory corresponds to a previous, second time. The second place is located in the place to which the first vector points in the first vector. This gives an impression of a fluid movement of the light modulation function along the trajectory, which can be perceived as pleasant.

In order to keep the calculation effort for the trajectory particularly low, it is advantageous for low costs in the realization if the trajectory is predicated on a linear prediction.

A visually appealing effect by a particularly natural-looking appearance for the viewer is achieved when the trajectory each has a beginning and one end, the beginning is located on an imaginary horizontal line. The line is located in an area that corresponds to an upper area of a vehicle-formed light image, preferably the upper boundary of the formed light image and there has the first trajectory of the trajectory and the trajectory further horizontally laterally and / or vertically down to the end runs.

A cost-effective implementation is possible if the at least one light modulation function is an input / output modulation, which is preferably divided into equally long time intervals.

To make the optical effect particularly appealing to the viewer, it is favorable if the at least one light modulation function is a substantially sinusoidal modulation, which is preferably subdivided into equally long time intervals. In this context, a substantially sinusoidal modulation means that the course of the modulation need not exactly correspond to a sine function, but may also have a sinusoidal profile, such as composite half-arcs. The beneficial effect is a smooth transition between a luminous and a non-luminous image area.

Moreover, it is advantageous to produce a favorable optical effect for the viewer, if the light modulation function can be formed of a time-dependent two-dimensional function, in particular of a polynomial, wherein the function value of the polynomial in magnitude and slope in the intersections of at least a cut trajectory substantially corresponds to the function value of the normal of the trajectories at the same time in magnitude and slope. This can create a visually pleasing impression for the viewer. In this context, a substantial correspondence of both function values in magnitude and slope means that, for example, by using an interpolation function, the magnitude and the slope can be adjusted to achieve an improved curve of a polynomial, for example with respect to a lower order of the polynomial, resulting in a reduced computational effort in the calculation of the polynomial can lead.

The optical effect for the viewer can be further improved by using approximation functions, preferably spline or Bezier interpolations, to determine the polynomials.

It is advantageous if the polynomials have at most a degree of two in order to keep the cost of their calculation low.

A particularly homogeneous impression of the visual effect for the viewer is achieved when the size of pattern details that illuminate or not even illuminate, for example, snowflakes or raindrops in the projection pattern depends on the parameter, measured in a plane transverse to the direction of illumination of the vehicle headlight at a distance within the field of vision in front of the vehicle.

The distance is preferably in a range between 1 m and 5 m in front of the vehicle, more preferably in a range between 1 m and 50 m in front of the vehicle.

The parameter preferably corresponds to the precipitation size parameter and is particularly preferably larger by at least a factor of three than the precipitation parameter.

The object is also achieved by a device according to the invention for generating a light distribution in front of a vehicle, in particular a headlight, in which said method steps are executable.

In a device according to the invention, it is advantageous if the controllable arrangement of a plurality of individually adjustable optoelectronic elements of the optoelectronic component is set up to be controlled with a switching frequency which is determined by the

Parameter dependent, wherein the switching frequency is preferably between 100 Hz and 1500 Hz. Within the limits mentioned, components are commercially available, so that a cost-effective implementation can be achieved. The lower border ensures a flicker-free image for the viewer.

In addition, it is advantageous if the duty cycle is set in dependence on a desired operating temperature of the optoelectronic device so that it is greater than or equal to the value 0.5. This can lead to a particularly long service life of the optoelectronic component being achieved, which is particularly important for applications in the automotive sector.

In addition, it is advantageous if a means for detecting the ambient temperature, a temperature sensor of the vehicle or a telecommunications means for receiving a temperature value, which is determined for the geographical location of the vehicle, preferably from an electronic service, and provided by the electronic service, is included.

Furthermore, it is favorable if a means for detecting the precipitation is a rain sensor, for example of a vehicle windshield wiper system or a video-based camera system of a vehicle, preferably a driver assistance system.

Moreover, it is favorable if a means for detecting the vehicle speed is a tachometer of a vehicle or a video-based camera system of a vehicle, preferably a driver assistance system is included.

It is particularly advantageous if the optoelectronic component is a DMD digital micro-mirror device, since commercial components are available, so that a cost-effective implementation can be achieved.

It is particularly advantageous if the light source comprises at least one light emitting diode, preferably a high current or power LED, or at least one laser diode. This allows an efficient design and small size of the device can be achieved.

A further development of the invention forms an assembly comprising at least one aforementioned device, wherein the assembly forms a headlight component which can be mounted in a vehicle. The assembly may further include, for example, a headlight housing and is mountable in a vehicle. Thus, a simple assembly and maintenance of the device is ensured in a vehicle.

The invention and its advantages are described in more detail below by means of non-limiting exemplary embodiments, which are illustrated in the accompanying drawings. 1 shows a method according to the invention, FIG. 2 shows a side view of a vehicle with precipitation and a conventional headlight, FIG. 3 shows a side view of the vehicle with precipitation and a headlight according to the invention, [0071] FIG. 4 shows a detailed view of the viewing area with segments shown in the illumination according to the invention, [0072] FIG. 5 shows the detail view of the viewing area with illumination segmented according to the invention, [0073] FIG. 6 shows a perspective view of a first embodiment of a device of a vehicle headlight according to FIG 7 shows a perspective view of a second embodiment of a device of a vehicle headlamp according to the invention; FIG. 8 shows a view from the front of an optoelectronic component with an enlarged detail of optoelectronic elements contained in FIG. 9. [0076] FIG a block diagram of an inventive Figure 10 is a snapshot of precipitation in front of a stationary vehicle as seen by the driver, Figure 11 is a snapshot of precipitation in front of a moving vehicle as seen by the driver, Figure 12 is a functional diagram 13 shows a timing diagram for driving micromirrors, FIG. 14 shows a first exemplary embodiment of an overlay function, FIG. 15 shows a second exemplary embodiment of an overlay function, [0083] FIG. 16 shows an optoelectronic component 17 shows the optoelectronic component according to FIG. 16 at a second time, FIG. 18 shows the optoelectronic component according to FIG. 16 in an enlarged detail, [0086] FIG. FIG. 19 shows an optoelectronic component with a cell-like superimposition function at a first point in time fourth exemplary embodiment, FIG. 20 shows the optoelectronic component with the cell-shaped superimposition function according to FIG. 19 at a second time.

Embodiments of the invention will now be explained in more detail with reference to FIGS. 1 to 20. In particular, important parts are shown for the invention in a vehicle headlamp, it being understood that a vehicle headlamp contains many other parts, not shown, which allow a meaningful use in a vehicle itself. For clarity, therefore, for example, the control electronics, other mechanical elements or brackets of the vehicle headlight are not shown.

FIG. 1 shows a method 1000 according to the invention for generating a light distribution in front of a vehicle. The following method steps are carried out: [0090] - Generating 1010 of a light beam through at least one light source 2, 12, [0091] emitting 1020 of the light beam in the direction of an optoelectronic device 7, 17, comprising a controllable arrangement of a plurality of individually adjustable optoelectronic elements 8 in the form of a two-dimensional matrix, selecting 1030 a light distribution 20, 21, 22 stored in a data memory 10 by means of a selection unit 15 and retrieving the light distribution 20 from the data memory 10, detecting 1040 [0094] an ambient temperature 55 to a temperature parameter 51, and / or [0095] - a precipitation 56 to a precipitation intensity parameter 52 and / or a precipitation parameter 53, and / or [0096] - a vehicle velocity 57 to a velocity parameter 52, [0097] - determining 1050 temperature 51, precipitation intensity 52, precipitation [0098] Defining 1060 an overlay function 71 from [0099] - the at least one parameter 50, and [00100] - a duty cycle 69 in driving and modulating the mirrors of FIG Optoelectronic device 7, 17, and [00101] - Overlay 1070 of the light distribution 20 with the overlay function 71 to a light matrix 80, - 1080 driving the optoelectronic device 7, 17 through the light matrix 80 by means of the output unit 6, after a conversion of Light matrix 80 in a corresponding video signal 81, [00103] - Modulating 1090 of the incident light beam through the optoelectronic component 7, 17 and at least partially reflecting the light beam in the direction of at least one projection optics 4, 14, [00104] - Projecting 1100 of the modulated light beam through the at least one projection optics 4, 14 and forming a light image in front of the vehicle.

Fig. 2 shows a vehicle with headlamps in a side view, wherein precipitation, for example by precipitation elements in the form of raindrops or snowflakes, can be seen.

In Fig. 3, a vehicle with headlights is shown in a side view, wherein a region "detail A" is located, in which light can be reflected by the precipitation elements, which can adversely affect the driver's view in the direction of travel, such as by an optical irritation of the eye, which can lead to fatigue and even dazzling the driver.

Fig. 4 shows an enlarged detail A of FIG. 3 and represents a lighting device of a vehicle, which performs the inventive method, with drawn light segments. By a projection system light is emitted line by line and the light through the projection system alternately switched dark. In this embodiment, a horizontally oriented stripe pattern is shown. The light intensity of the luminous lines is approximately twice as bright as that in the case that no fringe pattern is formed by the projection system, ie in a continuously lit system or vehicle headlights. The average brightness, measured in a plane transverse to the illumination direction of the vehicle headlight at a distance within the field of vision in front of the vehicle, preferably in a range between 1 m and 5 m in front of the vehicle, more preferably in a range between 1 m and 50 m before the Vehicle can thus be the same size for the headlight according to the invention, as in a conventional headlight.

Fig. 5 illustrates the technical effect of the inventive method of FIG. 1 enlarged in detail A, wherein the non-illuminated precipitation elements are not shown. It can be seen that the illuminated precipitation elements are significantly reduced in number, for example, when only 50% of the luminous area of a headlamp glow, by a uniform stripe pattern is superimposed. For example, to achieve the same brightness in comparison with a conventional headlight, the luminous intensity of the luminous strip-shaped region is twice as strong as the comparable regions of a conventional headlight.

The overlaying of the light distribution 20 with the overlay function 71 to the light matrix 80 is effected by associating each element of the overlay function 71 with an element of the light distribution 20 and is transformed by a transfer function. The transfer function corresponds to an operation of multiplication. The number of those elements of the light matrix 80 whose values are substantially zero after the transformation is between 30% and 70%, preferably between 40% and 60%, particularly preferably between 45% and 55% of the total number of elements of the light matrix 80. The values of the elements of the light matrix 80 which are substantially nonzero after the transformation are each greater in magnitude than the magnitudes of the associated values in the light distribution 20. In this context, two elements associated with one another are understood as meaning one element in each case Overlapping function, and each one element of a light distribution, both located in the same place, for example, the same pixel of a light matrix 80.

The value of the respective element is substantially zero if it is significantly below the original reference value of the same element, namely that of full-area illumination. In other words, the value is analogously zero, for example, if it is 50% or even 10% below the reference value.

The overlay function 71 may comprise a static projection pattern, such as a stripe-shaped pattern oriented line by line, column-wise or obliquely, or a checkerboard-like pattern or a uniformly distributed random pattern.

It is also possible that the selected projection pattern is switched during operation in order to achieve different lighting effects that are perceived in the respective driving situation as pleasant as possible for the human eye of the driver. The parameter can also dynamically adjust the respective projection pattern. This means that, for example, the line spacing can be adapted dynamically to the current requirements.

6 shows a first embodiment of an assembly according to the invention or a device according to the invention in the form of a vehicle headlight 1. The vehicle headlight 1 comprises in this example a light source 2, a primary optic 3, a projection optics 4 and an optoelectronic component 7, and a drive unit 9. The light source 2, which may contain, for example, a light-emitting diode or power LED and the primary optics 3 for focusing a light beam, is set up to illuminate the optoelectronic component 7. A headlight component of the assembly, which has the device according to the invention and, for example, a headlight housing, is not shown.

The optoelectronic component 7 may comprise a plurality of optoelectronic elements 8 arranged in a two-dimensional matrix. In this first embodiment, the optoelectronic elements 8 are individually controllable micromirrors, in which the reflection effect of each individual element of the matrix is variably adjustable, for example a DMD.

The optoelectronic component 7 can reflect the incident light in the direction of a projection optical system 4, wherein the controlled matrix elements individually adjust their reflection factor by modulating the angles of the micromirrors and modulating a desired light distribution onto the incident light beam. The projection optics 4 is oriented in the emission direction of the vehicle headlight 1 and thus produces the desired light distribution in front of the vehicle.

The control of the optoelectronic component 7 is carried out by the drive unit 9, in which a desired light distribution can be calculated and output to the required control of the optoelectronic elements 8 in the form of control signals to the optoelectronic component 7.

Fig. 7 shows a second embodiment of an assembly according to the invention or a device according to the invention in the form of a Fahrzugscheinwerfers 11. A light source 12, for example, a light emitting diode, high-current LED power LED or a laser diode and a primary optics 13 for bundling from the light source 12, is arranged to illuminate an optoelectronic component 17. A headlight housing of the module is not shown.

The optoelectronic component 17 comprises a plurality of optoelectronic elements arranged in a two-dimensional matrix. In this second embodiment, the optoelectronic elements 8 are individually controllable translucent elements in which the light transmission effect of each element of the matrix is variably adjustable beispielswei se LCD.

The optoelectronic component 17 can transmit the incident light in the direction of a projection optical system 14, wherein the controlled matrix elements individually adjust their light transmission and modulate a desired light distribution onto the incident light beam. The projection optics 14 is oriented in the emission direction of the vehicle headlight 11 and thus produces the desired light distribution in front of the vehicle.

The control of the optoelectronic component 17 is effected by the drive unit 19, in which a light distribution can be calculated and the necessary control of the optoelectronic elements, for example the pixels of an LCD, are output to the optoelectronic component 17 in the form of control signals.

In addition to the variants of the optoelectronic component 7, 17 shown in FIGS. 6 and 7, it is of course also possible to use other technologies which enable a corresponding modulation of the light. For the sake of completeness, LCoS systems LCoS, "Liquid Crystal on Silicon" are therefore also mentioned.

The modulation of the light allows a segmentation of the light distribution on the road, that is, the light distribution projected onto the road can be controlled individually for different solid angles. For a light image projected on a roadway, the number of segments that can be controlled individually by a vehicle headlight according to the invention is important in order to generate light distributions that are individually adapted for different driving situations. The number of these segments depends, for example, on the number of micromirrors and is, for example, 854 × 480 micromirrors or pixels in a rectangular matrix arrangement.

If two headlights are used for vehicles, the segments can be strung together and the number of segments can be doubled. Usually, in the installation position of the vehicle headlamp more segments in the horizontal direction than in the vertical direction are needed. For this reason, in practice, the light distributions segmented by the optoelectronic components are frequently strung together by two vehicle headlights on the short sides of the matrix arrangement, thus doubling the horizontal resolution.

It is also a complete or even partial overlay or overlap of two or more light distributions possible, for example, to achieve a stronger contrast in image areas.

FIG. 8 shows an example of an optoelectronic component 7 in the form of a DMD in front view. An enlarged image section shows optoelectronic elements 8 arranged in matrix form, which comprise individually controllable micromirrors, in which example every second micromirror is tilted.

9 shows an exemplary embodiment of an electrical block diagram of a device according to the invention for generating a light distribution in front of a vehicle, in this example a vehicle headlight 1 according to FIG. 6, which is suitable for carrying out the method 1000 according to the invention. A microprocessor 900, an output unit 6, a data memory 10, a sensor device 920 and further vehicle electronic devices or adapters 930 are interconnected via a CAN bus 910. An output unit 6 controls the optoelectronic component 7.

The controllable arrangement of a plurality of individually adjustable optoelectronic elements 8 of the optoelectronic component 7 is adapted to be driven with a switching frequency which depends on the parameter 50, wherein the switching frequency is preferably between 100 Hz and 1500 Hz.

The duty cycle 69 is, for example, adjusted so that it is greater than or equal to the value 0.5 depending on a desired operating temperature of the optoelectronic component 7.

An ambient temperature sensing means 55 may be a temperature sensor of the vehicle. Alternatively, the means may also be telecommunication means for receiving a temperature value determined for the geographic location of the vehicle by an electronic service and provided by the electronic service.

A means for detecting the precipitate 56 may be a rain sensor of a vehicle windshield wiper system or a video-based camera system of a vehicle, for example a driver assistance system.

A means for detecting the vehicle speed 57 may be a tachometer of a vehicle or a video-based camera system of a vehicle, preferably a driver assistance system.

The optoelectronic component 7 is a DMD digital micromirror device in this exemplary embodiment.

The light source 2 may comprise one or more light-emitting diodes, for example, in each case a high-current or power LED, or else one or more laser diodes.

Furthermore, at least the at least one light source 2, the at least one projection optics 4 and the optoelectronic component 7 form a headlight component which can be mounted in a vehicle, wherein at least one headlight component can be mounted in a vehicle.

FIG. 10 shows a snapshot of precipitation in front of a stationary vehicle as seen by the driver, in FIG. 11 a snapshot of precipitation in front of a moving vehicle as seen by the driver. It can be seen that the precipitation elements follow a trajectory, that is, a trajectory, depending on the vehicle speed. The trajectory also depends on the nature of the precipitation elements, ie raindrops or snowflakes. The nature of the precipitation elements depends on the temperature outside the vehicle, at temperatures below freezing snowflakes form, as is well known.

In the method according to the invention according to the functional diagram of FIG. 12, a particularly favorable optical effect for the eye of the driver can be achieved if the determination of overlay function 71 is determined by means of a trajectory 110, 210, at least by a prediction function 31, 32, 33, 34. 310, 410 of a predicted trajectory of a hypothetical, falling precipitation element in the field of vision in front of the vehicle takes place. In this case, the at least one trajectory 110, 210, 310, 410 is calculated from the parameter 50. The trajectory 110, 210, 310, 410 is defined in each of its function values along the course of each by a course vector 115, 116.

In addition, it is particularly advantageous for the driver's eye to have an optical effect if a time-dependent modulation function 40 defined by a modulation source 45 is determined along each trajectory 110, 210, 310, 410. Time intervals 46 determine the repetition rate of the modulation function 40, as shown in FIG. 13. The abscissa 41 of the modulation function 40 extends locally along the respective trajectory 110, 210, 310, 410 and is superimposed by pointwise multiplication and forms a respective overlay function 71 in the form of a light modulation function 61. In this exemplary embodiment, the at least one light modulation function 61 is divided into time intervals 46, each of equal length, is an input / output modulation.

In Fig. 14 and Fig. 15 it can be seen how the light modulation function 61 can be formed.

When superimposing the respective light modulation function 61 with the light distribution 20, the magnitude of a function value of the respective light modulation function 61 at a first location 101 of the respective trajectory 110, 210, 310, 410 at a first time 47 corresponds to the magnitude of a function value of the respective one Light modulator function 61 at a second location 102 of the respective trajectory 110, 210, 310, 410 at a previous, second time 48. The second location 102 is located at the location where the history vector 115, 116 in the first location 101 at the first time 47 shows.

In this case, the at least one trajectory 110, 210, 310, 410 may be predicted by a linear prediction in order to keep the computational complexity low.

The at least one trajectory 110, 210, 310, 410 each has a beginning 111, 211 and an end 112, 212, respectively. The beginning 111, 211 is located on an imaginary horizontal line 100, which can be seen in FIG. The line 100 is located in an area that corresponds to an upper area of a vehicle-formed light image and the upper boundary of the formed light image and there has a first gradient vector of the at least one trajectory, and the at least one trajectory 110, 210, 310, 410 runs further horizontally laterally and / or vertically down to the end 112, 212. Gradient vectors 115, 116 at later times 47, 48 can be seen in the figure.

In an alternative embodiment, not shown, the modulation function 61, which is subdivided into respectively equal time intervals 46, may be a substantially sinusoidal modulation.

The light modulation function 61 can be formed for example by a time-dependent two-dimensional function or a polynomial 510, 610, 710, wherein the function value of the polynomial 510 in magnitude and slope in the intersections with the Trajek-gates 110, 210, 310 and 410 in Substantially corresponds to the function value of the normals 120, 220, 320, 420 of the trajectories 110, 210, 310 and 410 at the same time 100 in magnitude and slope. At each subsequent time, a new polynomial is determined.

A polynomial 510, 610, 710 may, for example, be represented mathematically by a power series, which in turn may be illustrated graphically in accordance with the representations of a curve in the figures.

In order to minimize the effort for determining the polynomials 510, 610, 710, a limited number of trajectories 110, 210, 310, 410 can be used to determine the polynomials 510, 610, 710 and the polynomials by approximation functions, for example be determined by spline or Bezier interpolations.

Approximation functions are suitable in this embodiment to describe polynomials. The approximation functions, in turn, themselves can be mathematically described by polynomials. In practice, multiple polynomials can often be formed to achieve the desired effect.

The light modulation function 61 can be applied not only to the trajectories 110, 210, 310, 410 but also to the polynomials 510, 610, 710. In this case, it is not necessary to determine a large number of trajectories, but a reduced number of trajectories may be used to determine polynomials associated with a light modulation function. Consequently, along a polynomial 510, 610, 710, the same adjustment of the mirrors 8 of an electro-optical component 7 takes place in order to produce a light intensity in the projection direction of the vehicle headlight 1.

Accordingly, the modulation function 40 can be applied to different trajectories 110, 210, 310, 410 in various ways. From this context, it is clear that the modulation function 40 can be transformed to the trajectories 110, 210, 310, 410 by transforming the modulation function 40, for example, to the different lengths of the individual paths of the trajectories 110, 210, 310, 410.

In this context, the above-mentioned coincidence in the polynomial 510 and the normal 120 to the trajectory 110 in magnitude and slope means that it is substantially within limits, which is the determination of a polynomial by reduction to a low-order polynomial to simplify. The use of a polynomial with at most second degree is advantageous.

[00150] With the slope at a point of a function or curve, the amount of the first is

Derivation of the function in this point according to the mathematical analysis meant.

The size of pattern details in the projection pattern or in the overlay function, for example, in a plane transverse to the direction of illumination of the vehicle headlight at a distance within the field of vision in front of the vehicle, preferably in a range between 1 m and 5 m in front of the vehicle, particularly preferably in range between 1 m and 50 m in front of the vehicle. In this case, the size may depend on the parameter 50, preferably on the precipitation size parameter 53, and may be greater than the precipitation parameter 53 by at least a factor of three.

16 shows an enlarged view of the optoelectronic component 7 as a third exemplary embodiment of an overlay function 71 at a first point in time in an image detail. Four trajectories 850, 851, 852, 853 are shown, which are exemplary for the trajectory of four precipitation elements. It can also be seen how the polynomials 860, 861, 862, which are represented by a position or position of a micromirror of the DMD chip, that is to say the optoelectronic component 7, are reflected in the light in the projection direction of the vehicle headlight. The resolution of the optoelectronic component 7 determines the fineness of the optical representation of the polynomials 860, 861, 862. The line width of the polynomial 860, 861, 862, which is determined transversely to the course of a polynomial, can be determined by the light modulation function.

FIG. 17 shows the optoelectronic component 7 with the superimposition function 71 according to FIG. 16 at a second time, likewise as an enlarged illustration of an image detail. The polynomials 870, 871, 872 are determined on the four trajectories 850, 851, 852, 853 at the second time.

18 shows an enlarged view of the optoelectronic component 7 with the overlay function 71 according to FIG. 16 in an enlarged image detail as a further exemplary embodiment of a heterodyning function. The polynomials 860, 861, 862 can be seen running parallel due to the selected image detail.

FIG. 19 shows the optoelectronic component 7 with a cell-like overlay function 71 as a fourth exemplary embodiment at a first point in time. The polynomials 880, 881, 882 are recognizable as parallel running, horizontally oriented fringe patterns due to the parameter 50, here for example as zero vehicle speed.

FIG. 20 shows the optoelectronic component 7 with a cell-like overlay function according to FIG. 19 at a second point in time. The polynomials 880, 881 can be seen running parallel. This is to illustrate that the horizontally oriented fringe pattern causes a downwardly moving effect in time. LIST OF REFERENCE SIGNS: 1, 11 Vehicle headlights 2, 12 Light source 3, 13 Primary optics 4, 14 Projection optics 5 Control device 6 Output unit 7, 17 Optoelectronic component 8 Optoelectronic element 9, 19 Actuation unit 10 Data memory 15 Selection unit 20, 21, 22 Light distribution 30 All of the prediction functions 31, 32, 33, 34 Prediction function 35 Prediction unit 40 Modulation function 41 Abscess of modulation function 45 Modulation source 46 Time interval 47 First time 48 Second time 50 Parameters 51 Temperature parameters 52 Precipitation intensity parameter 53 Precipitation parameter 54 Velocity parameter 55 Means for detecting an ambient temperature 56 means for detecting a precipitation 57 means for detecting a vehicle speed 60 modulator 61 light modulation function 69 duty 70 superposition unit 71 projection pattern 80 light matrix 81 video signal 100 imaginary line 101 first place 102 second O rt 110, 210, 310, 410, 850, 851, 852, 853 Trajectory 111.211 Start of trajectory 112.212 End of trajectory 115, 116 Trace vector 120, 220, 320, 420, 121, 221, 311, 421 Normals 510, 610, 710, 860, 861, 862 , 870, 871, 872, 880, 881, 882 graphical representation of the polynomial 900 microprocessor 910 CAN bus 920 sensor device 930 further vehicle electronic devices or adapters

Claims (24)

claims A method (1000) for generating a light distribution in front of a vehicle, characterized in that the following method steps are carried out: - generating (1010) a light beam through at least one light source (2, 12), - emitting (1020) the light beam in the direction of optoelectronic component (7, 17) comprising a controllable arrangement of a plurality of individually adjustable optoelectronic elements (8) in the form of a two-dimensional matrix, selecting (1030) a light distribution (20, 21, 22) stored in a data memory (10) by means of a selection unit (15) and retrieving the light distribution (20) from the data memory (10), - detecting (1040) - an ambient temperature (55) to a temperature parameter (51), and / or - a precipitate (56) to a precipitation intensity parameter (52) and / or a precipitation size parameter (53), determining (1050) the temperature (51), precipitation intensity (52), precipitation magnitude n- (53) as at least one parameter (50), - defining (1060) an overlay function (71) from the at least one parameter (50), superimposing (1070) the light distribution (20) with the overlay function (71) into one Light matrix (80), driving (1080) of the optoelectronic component (7, 17) through the light matrix (80) by means of the output unit (6), modulating (1090) of the incident light beam through the optoelectronic component (7, 17) and at least partially reflecting the light beam in the direction of at least one projection optics (4, 14), projecting (1100) the modulated light beam through the at least one projection optics (4, 14) and forming a light image in front of the vehicle. 2. The method according to claim 1, characterized in that during detection (1040) also a vehicle speed (57) to a speed parameter (54) is detected, which is taken into account in determining (1050) of the at least one parameter (50). 3. The method of claim 1 or 2, characterized in that when defining (1060) of a superposition function (71) also a duty cycle (69) for the control and modulation of the mirror of the optoelectronic component (7, 17) is taken into account. 4. The method according to any one of claims 1 to 3, characterized in that the superimposition of the light distribution (20) with the overlay function (71) to the light matrix (80) by each element of the overlay function (71) each with an element of light distribution ( 20) and is transformed by a transfer function, wherein the transfer function preferably corresponds to an operation of multiplication or addition, wherein the number of those elements of the light matrix (80) whose values after transformation are essentially zero is between 30% and 70%. , preferably between 40% and 60%, more preferably between 45% and 55% of the total number of elements of the light matrix (80), and the values of the elements of the light matrix (80) that are substantially nonzero after transformation, each amount is greater than the amounts of associated values in the light distribution (20). 5. The method according to any one of claims 1 to 4, characterized in that the overlay function (71) comprises a static projection pattern, preferably a stripe-shaped pattern, which is oriented as a projected light image of a light distribution in front of the vehicle line by line vertically, columnwise horizontally or obliquely, or a checkered pattern or evenly distributed random pattern. 6. The method according to any one of claims 1 to 5, characterized in that the determination of the overlay function (71) at least one prediction function (31, 32, 33, 34) comprising a trajectory (110, 210, 310, 410, 850, 851, 852, 853) of a predicted trajectory each of a hypothetical, falling precipitation element in the field of vision in front of the vehicle, wherein the trajectory (110, 210, 310, 410, 850, 851, 852, 853) at least from the parameter (50 ) and the trajectory (110, 210, 310, 410, 850, 851, 852, 853) in each of its function values is defined along its course by a gradient vector (115, 116). 7. The method according to claim 6, characterized in that along the trajectory (110, 210, 310, 410, 850, 851, 852, 853) a time-dependent modulation function (40) by a modulation source (45) at the time intervals ( 46) defines the repetition rate of the modulation function (40), is determined, and the abscissa (41) of the modulation function (40) extends along the trajectory (110, 210, 310, 410, 850, 851, 852, 853) and preferably pointwise is superimposed by multiplication and thereby the overlay function (71) is formed. 8. The method according to claim 6 or 7, characterized in that in the superimposition of the overlay function (71) with the light distribution (20) the amount of a function value of the light modulation function (61) at a first location (101) of the trajectory (110, 210, 310, 410, 850, 851, 852, 853) at a first time (47), the magnitude of a function value of the light modulation function (61) at a second location (102) of the trajectory (110, 210, 310, 410, 850, 851 , 852, 853) at a previous, second time (48), the second location (102) being located at the location to which the history vector (115, 116) in the first location (101) at the first time (47) shows. 9. The method according to any one of claims 6 to 8, characterized in that the trajectory (110, 210, 310, 410, 850, 851, 852, 853) is predicated by a linear prediction. 10. The method according to any one of claims 6 to 9, characterized in that the trajectory (110, 210, 310, 410, 850, 851, 852, 853) has a beginning (111, 211) and an end (112, 212) wherein the start (111, 211) on a horizontal line (100) located in an area corresponding to an upper area of a photograph formed in front of the vehicle, preferably the upper limit of the formed photograph and there the first gradient vector (115 , 116) of the trajectory, and the trajectory (110, 210, 310, 410, 850, 851, 852, 853) continues to extend horizontally laterally and / or vertically down to its end (112, 212). 11. The method according to any one of claims 7 to 10, characterized in that the modulation function (40), which is preferably divided into time intervals (46), which are preferably of equal length, is an input / output modulation. 12. The method according to any one of claims 7 to 11, characterized in that the modulation function (40), which is preferably divided into time intervals (46), which are preferably of equal length, is a substantially sinusoidal modulation. 13. The method according to any one of claims 7 to 12, characterized in that at least one time-dependent two-dimensional function in the form of a polynomial (510, 610, 710, 860, 861, 862, 870, 871, 872) can be formed, wherein the function value of the polynomial (510, 610, 710, 860, 861, 862, 870, 871, 872) in magnitude and slope in the intersections with the trajectory (110, 210, 310, 410, 850, 851, 852, 853) substantially the functional value of the normal (120, 220, 320, 420, 121, 221, 321, 421) to the trajectory (110, 210, 310, 410, 850, 851, 852, 853) at the same time (47, 48) in FIG Magnitude and slope, where the polynomial (510, 610, 710, 860, 861, 862, 870, 871, 872) can be superimposed on the light modulation function (61) at a time (47, 48) and along the course of the polynomial (510, 610, 710, 860, 861, 862, 870, 871, 872) is superimposed on the same function value of the light modulation function (61) and therefrom the. 14. The method according to claim 13, characterized in that for determining the polynomials (510, 610, 710, 860, 861, 862, 870, 871, 872) approximation functions, preferably spline or Bezier interpolations, are used. 15. The method according to claim 14, characterized in that the polynomials (510, 610, 710, 860, 861, 862, 870, 871, 872) have at most a degree of two. 16. The method according to any one of claims 7 to 15, characterized in that the size of pattern details in the projection pattern, measured in a plane transverse to the direction of illumination of the vehicle headlight at a distance within the field of vision in front of the vehicle, preferably in a range between 1 m and 5 m in front of the vehicle, more preferably in a range between 1 m and 50 m in front of the vehicle on which parameter (50) depends, preferably from the precipitation parameter (53), more preferably by at least a factor of three greater than the precipitation parameter (53) , 17. A device for generating a light distribution in front of a vehicle, in which the method steps according to one of claims 1 to 16 can be executed, comprising a light source (2), a primary optic (3), a projection optics (4), an optoelectronic component (7). , comprising a controllable arrangement of a plurality of individually adjustable optoelectronic elements (8), and a drive unit (9), characterized in that the switching frequency of the controllable arrangement of a plurality of individually adjustable optoelectronic elements (8) of the optoelectronic component (7, 17 ) depends on the parameter (50), the switching frequency preferably being between 100 Hz and 1500 Hz. 18. The device according to claim 17, characterized in that the duty cycle (69) in response to a desired operating temperature of the optoelectronic component (7, 17) is set so that it is greater than or equal to the value 0.5. A device according to claim 17 or 18, characterized in that a means for detecting the ambient temperature (55) comprises a temperature sensor of the vehicle or telecommunication means for receiving a temperature value which is preferably determined by an electronic service for the geographical location of the vehicle, and is provided by the electronic service is included. 20. Device according to one of claims 17 to 19, characterized in that a means for detecting the precipitate (56) is a rain sensor of a vehicle windshield wiper system or a video-based camera system of a vehicle, preferably a driver assistance system is included. 21. Device according to one of claims 17 to 20, characterized in that a means for detecting the vehicle speed (57) is a speedometer of a vehicle or a video-based camera system of a vehicle, preferably a driver assistance system is included. 22. Device according to one of claims 17 to 21, characterized in that the optoelectronic component (7, 17) is a DMD (Digital Micromirror Device). 23. Device according to one of claims 17 to 22, characterized in that the light source (2, 12) comprises at least one light emitting diode, preferably a high current or power LED, or at least one laser diode. 24. Assembly, comprising at least one device according to one of claims 17 to 23, characterized in that the assembly forms a vehicle-mounted headlight component. For this 10 sheets of drawings