EP3899360B1 - Lighting system for a motor vehicle - Google Patents

Description

• einen ersten Laserscanner mit zumindest einer Laserlichtquelle, wobei der Laserlichtquelle ein erster Mikroscanner zugeordnet ist, welcher erste Mikroscanner dazu eingerichtet ist, Laserstrahlen der Laserlichtquelle auf ein erstes Lichtkonversionselement zu lenken, wodurch an dem ersten Lichtkonversionselement sichtbares Licht abgestrahlt und ein erstes Lichtbild erzeugt wird, wobei dem ersten Lichtkonversionselement ein optisches Abbildungssystem zugeordnet ist, um das erste Lichtbild vor dem Beleuchtungssystem als erste Teillichtverteilung abzubilden,
• einen zweiten Laserscanner mit zumindest einer Laserlichtquelle, wobei der Laserlichtquelle ein zweiter Mikroscanner zugeordnet ist, welcher zweite Mikroscanner dazu eingerichtet ist, Laserstrahlen der Laserlichtquelle auf ein zweites Lichtkonversionselement zu lenken, wodurch an dem zweiten Lichtkonversionselement sichtbares Licht abgestrahlt und ein zweites Lichtbild erzeugt wird, wobei dem zweiten Lichtkonversionselement ein optisches Abbildungssystem zugeordnet ist, um das zweite Lichtbild vor dem Beleuchtungssystem als zweite Teillichtverteilung abzubilden,

wobei die erste und die zweite Teillichtverteilung abhängig von zumindest drei an den jeweiligen Mikroscannern einstellbaren Parametern veränderbar sind,

• wobei die veränderbare erste und zweite Teillichtverteilung eine gemeinsame veränderbare Gesamtlichtverteilung vor dem Beleuchtungssystem erzeugen und sich zumindest teilweise überlappen, wobei die Gesamtlichtverteilung einen Öffnungswinkel aufweist,
• und wobei der erste und der zweite Mikroscanner jeweils um eine Achse, welche parallel zueinander angeordnet sind, drehbar gelagert sind, wobei der erste und der zweite Mikroscanner um eine Nulllage mit einer festlegbaren Schwingungsamplitude AMP um die Achse schwingen können, wobei die Schwingungsamplitude durch einen Maximalwert MEMSmax begrenzt ist, wobei die Schwingungsamplitude AMP eine horizontale Breite der jeweils erzeugten Teillichtverteilung bestimmt,
• und wobei der erste und der zweite Mikroscanner entlang einer gedachten Linie angeordnet sind, wobei die Nulllage des ersten Mikroscanners um einen ersten Winkel ALPHA und die Nulllage des zweiten Mikroscanners um einen zweiten Winkel ALPHA' zur gedachten Linie geneigt angeordnet sind, wobei der erste und der zweite Winkel invers zueinander sind,
• und wobei die erste und die zweite Teillichtverteilung jeweils einen Lichtschwerpunkt aufweisen, der dadurch charakterisiert ist, dass an diesem Punkt die jeweilige Lichtintensität maximal ist, wobei der Lichtschwerpunkt an den jeweiligen Mikroscannern entsprechend einer festlegbaren Lichtschwerpunktverschiebung LSPV verschiebbar ist,
• und wobei die Teillichtverteilungen jeweils um einen den jeweiligen Mikroscannern zuführbaren Offsetwert OFFSET verschiebbar sind,
  • eine Steuereinrichtung, welche eingerichtet ist, den ersten und den zweiten Mikroscanner anzusteuern, wobei das Schwingungsverhalten des ersten und zweiten Mikroscanners zumindest über die Parameter Schwingungsamplitude AMP, Lichtschwerpunktverschiebung LSVP, und Offsetwert OFFSET, welche durch die Steuereinrichtung veränderbar sind, steuerbar ist.
• Weiters betrifft die Erfindung ein Kraftfahrzeug mit zumindest einem erfindungsgemäßen Beleuchtungssystem.
• Laserprojektionssysteme können durch die Ablenkung eines Laserstrahles durch sogenannte Mikroscanner realisiert werden. Diese Mikroscanner können z.B. als in MEMS- oder MOEMS-Technik (Micro-Electro-Mechanical Systems bzw. Micro-Opto-Electro-Mechanical Systems) gefertigte Mikrospiegel ausgeführt sein, die nur wenige Millimeter Durchmesser aufweisen und in einer bzw. zwei Achsrichtungen in Schwingung versetzt werden können.

The invention relates to a lighting system for a motor vehicle, which lighting system comprises the following:

• a first laser scanner with at least one laser light source, wherein a first microscanner is assigned to the laser light source, which first microscanner is set up to direct laser beams from the laser light source onto a first light conversion element, whereby visible light is emitted at the first light conversion element and a first light image is generated, wherein an optical imaging system is assigned to the first light conversion element in order to image the first light image in front of the lighting system as a first partial light distribution,
• a second laser scanner with at least one laser light source, a second microscanner being assigned to the laser light source, the second microscanner being set up to direct laser beams from the laser light source onto a second light conversion element, as a result of which visible light is emitted at the second light conversion element and a second light image is generated, wherein an optical imaging system is assigned to the second light conversion element in order to image the second light image in front of the lighting system as a second partial light distribution,

wherein the first and the second partial light distribution can be changed depending on at least three parameters that can be set on the respective microscanners,

• wherein the changeable first and second partial light distribution generate a common changeable overall light distribution in front of the lighting system and at least partially overlap, the overall light distribution having an opening angle,
• and wherein the first and the second microscanner are each mounted rotatably about an axis which is arranged parallel to one another, wherein the first and the second microscanner can oscillate about a zero position with a definable oscillation amplitude AMP about the axis, the oscillation amplitude being limited by a maximum value MEMSmax is limited, with the oscillation amplitude AMP determining a horizontal width of the partial light distribution generated in each case,
• and wherein the first and second microscanners are arranged along an imaginary line, the zero position of the first microscanner being inclined by a first angle ALPHA and the zero position of the second microscanner being inclined by a second angle ALPHA' to the imaginary line, the first and the second angles are inverse to each other,
• and wherein the first and the second partial light distribution each have a light center which is characterized in that the respective light intensity is maximum at this point, the light center being displaceable on the respective microscanners in accordance with a definable light center shift LSPV,
• and wherein the partial light distributions can each be shifted by an offset value OFFSET that can be fed to the respective microscanners,
  • a control device that is set up to control the first and the second microscanner, wherein the vibration behavior of the first and second microscanner can be controlled at least via the parameters vibration amplitude AMP, light center shift LSVP, and offset value OFFSET, which can be changed by the control device.
• Furthermore, the invention relates to a motor vehicle with at least one lighting system according to the invention.
• Laser projection systems can be implemented by deflecting a laser beam using so-called microscanners. These microscanners can be designed, for example, as micromirrors manufactured using MEMS or MOEMS technology (Micro-Electro-Mechanical Systems or Micro-Opto-Electro-Mechanical Systems), which have a diameter of only a few millimeters and oscillate in one or two axis directions can be moved.

The oscillation amplitude determines the width of the generated light image or partial light distribution.

The oscillation speed, i.e. to vary the angular deflection over time in a microscanner (angular speed). Since a "slowly" moving point of light generates more light in the light conversion element than a point of light moving quickly, the light distribution can also be influenced in this way.

If two laser scanners are used, the partial light distributions of which together result in an overall light distribution, undesired effects can form with differently adjustable oscillation amplitudes, for example two brightness maxima in the overall light distribution. For example, lighting systems for motor vehicles with two laser scanners are off WO 2017/020054 A1 and EP 2 690 352 A1 known.

It is an object of the invention to provide an improved lighting system for motor vehicles.

• AMP = DOA
• OFFSET = ALPHA
• LSPV = 0°
  und die Parameter des zweiten Mikroscanners wie folgt festlegt sind:
  • AMP = DOA
  • OFFSET = -ALPHA
  • LSPV = 0°
    und wobei bei Nichterfüllung des Kriteriums die Parameter des ersten Mikroscanners wie folgt festgelegt sind: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMSmax}-\mathrm{ALPHA}\right)/2$$
    
    $$\mathrm{OFFSET}=\mathrm{MEMSmax}-\mathrm{AMP}$$
    
    $$\mathrm{LSPV}=\mathrm{DOA}-\mathrm{AMP}$$
    
    und die Parameter des zweiten Mikroscanners wie folgt festgelegt sind: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMSmax}-\mathrm{ALPHA}\right)/2$$
    
    $$\mathrm{OFFSET}=-\left(\mathrm{MEMSmax}-\mathrm{AMP}\right)$$
    
    $$\mathrm{LSPV}=-\left(\mathrm{DOA}-\mathrm{AMP}\right).$$
    

This object is achieved in that the control device is set up to receive a temporally variable input variable DOA, which represents a target opening angle of the overall light distribution, and the parameters oscillation amplitude AMP, light center shift LSVP, and offset value OFFSET of the first and second microscanner depending on the test result of a criterion of the input variable DOA, namely DOA ≤ (MEMSmax - ALPHA), where the maximum oscillation amplitude MEMSmax represents the maximum angle around the respective axis, and where the parameters of the first microscanner are defined as follows if the criterion is met:

• AMP = DOA
• OFFSET = ALPHA
• LSPV = 0°
  and the parameters of the second micro-scanner are set as follows:
  • AMP = DOA
  • OFFSET = -ALPHA
  • LSPV = 0°
    and wherein if the criterion is not met, the parameters of the first microscanner are set as follows: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMS\; max}-\mathrm{ALPHA}\right)/2$$
    
    $$\mathrm{OFFSET}=\mathrm{MEMS\; max}-\mathrm{AMP}$$
    
    $$\mathrm{LSPV}=\mathrm{DOA}-\mathrm{AMP}$$
    
    and the parameters of the second micro-scanner are set as follows: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMS\; max}-\mathrm{ALPHA}\right)/2$$
    
    $$\mathrm{OFFSET}=-\left(\mathrm{MEMS\; max}-\mathrm{AMP}\right)$$
    
    $$\mathrm{LSPV}=-\left(\mathrm{DOA}-\mathrm{AMP}\right).$$
    

Since laser light sources usually emit coherent, monochromatic light or light in a narrow wavelength range, but white mixed light is generally preferred or prescribed by law for the emitted light in motor vehicle headlights, the laser light sources are equipped with so-called light conversion elements for converting essentially monochromatic light into assigned to white or polychromatic light, "white light" being understood to mean light of such a spectral composition that produces the color impression "white" in humans. This light conversion element is designed, for example, in the form of one or more photoluminescence converters or photoluminescence elements, with incident laser beams from the laser light source impinging on the light conversion element, which usually has photoluminescence dye, and exciting this photoluminescence dye to photoluminescence, and thereby emitting light at a different wavelength or . The light output of the light conversion element essentially has the characteristics of a Lambertian radiator.

In the case of light conversion elements, a distinction is made between reflective and transmissive conversion elements.

The terms "reflective" and "transmissive" refer to the blue portion of the converted white light. In the case of a transmissive structure, the main propagation direction of the blue light component after passing through the converter volume or conversion element is essentially in the same direction as the propagation direction of the output laser beam. In a reflective structure, the laser beam is reflected or deflected at a boundary surface that can be assigned to the conversion element, so that the blue light component has a different propagation direction than the laser beam, which is usually designed as a blue laser beam.

In practice, the overall light distribution on the road is created by superimposing the partial light distributions, with the first laser scanner being located, for example, in a left-hand motor vehicle headlight and the second laser scanner being, for example, in a right-hand motor vehicle headlight, as a result of which the resulting overall light distribution is generated by a left and a right motor vehicle headlight of a motor vehicle .

Provision can advantageously be made for the laser light sources to be dimmable.

In an expedient embodiment it can be provided that—measured from the imaginary line—the first angle ALPHA is 2° and the second angle ALPHA′ is −2°.

Provision can be made for the microscanners to be in the form of quasi-static microscanners.

Microscanners can be one-dimensional (mirror moves in one direction only) or two-dimensional (mirror moves in two directions simultaneously). Most currently available microscanners work according to a resonant drive principle. The MEMS scanners essentially represent mechanical oscillating circuits that are excited at their resonant frequency and oscillate in a sinusoidal manner. This sinusoidal curve poses a major problem in terms of utilizing the installed laser power, since the light distribution is always brightest where the microscanner is lowest angular velocity reached. In the case of a sinusoidal oscillation, the edge area would appear brightest and the middle area or the center of the light distribution would appear darkest, which is why the laser diodes have to be dimmed considerably and can therefore only be used to a small percentage (approx. 40%).

This can be remedied by quasi-static micro-scanners, which can be arbitrarily controlled in terms of their angular velocity within certain physical limits (resonance frequencies,...). It is thus possible to direct a large part of the generated light into the middle or center of the partial light distribution, whereby utilization of the installed laser power of the laser light sources can be increased to up to approx. 90% with typical partial light distributions. 100% utilization is not possible, since the microscanner changes direction in the edge area, which means that the mirror is "decelerated" completely and then accelerated in the opposite direction. During this phase, the laser light sources are deactivated, because otherwise the light intensity would increase significantly in this reversal area due to the low average angular velocity, which is not desirable.

Provision can be made for the maximum value MEMSmax of the oscillation amplitude of the microscanner to be 6°.

Provision can also be made for the control device to control the laser light sources.

The object of the invention is also achieved by a motor vehicle with at least one lighting system.

It can be provided that the time-varying desired opening angle of the total light distribution DOA changes as a function of the speed of the motor vehicle, with an increase in the speed of the motor vehicle the desired opening angle DOA being reduced.

• Fig. 1 ein beispielhaftes Beleuchtungssystem mit einem ersten Laserscanner, welcher einen ersten Mikroscanner umfasst, und einem zweiten Laserscanner, welcher einen zweiten Mikroscanner umfasst, wobei die Mikroscanner jeweils um einen ersten bzw. einen zweiten Winkel geneigt sind, und wobei die Mikroscanner durch eine Steuereinrichtung veränderbare Parameter aufweisen, wobei der erste Laserscanner eine erste Teillichtverteilung und der zweite Laserscanner eine zweite Teillichtverteilung erzeugt, wobei die erste und die zweite Teillichtverteilung gemeinsam eine Gesamtlichtverteilung erzeugen, welche einen Öffnungswinkel aufweist, wobei die Gesamtlichtverteilung auf einem Messschirm abgebildet wird,
• Fig. 2 eine beispielhafte Kennlinie eines Mikroscanners, wobei eine Schwingungsamplitude AMP gegen die Winkelgeschwindigkeit aufgetragen ist, und wobei die maximale Schwingungsamplitude MEMSmax 6° beträgt,
• Fig. 3A eine Darstellung einer veränderten Schwingungsamplitude AMP der Kennlinie aus Fig. 2;
• Fig. 3B eine Darstellung einer Lichtschwerpunktverschiebung LSVP an der Kennlinie aus Fig. 2;
• Fig. 3C eine Darstellung einer Verschiebung einer Kennlinie durch einen Offsetwert OFFSET;
• Fig. 4A eine Darstellung der ersten bzw. zweiten Teillichtverteilung an dem Messschirm für verschiedene Öffnungswinkel, wobei der erste und der zweite Winkel der jeweiligen Mikroscanner Null beträgt;
• Fig. 4B eine Darstellung der Gesamtlichtverteilung an dem Messschirm, welche sich aus den Teillichtverteilungen aus Fig. 4A zusammensetzt;
• Fig. 5A erste Teillichtverteilungen für bestimmte Öffnungswinkel, wobei der erste Mikroscanner in diesem Beispiel um 2° geneigt ist, wobei für die einzelnen dargestellten Teillichtverteilungen der Lichtschwerpunkt in Richtung Zentrum verschoben sind;
• Fig. 5B zweite Teillichtverteilungen für bestimmte Öffnungswinkel, wobei der zweite Mikroscanner in diesem Beispiel um -2° geneigt ist, wobei für die einzelnen dargestellten Teillichtverteilungen der Lichtschwerpunkt in Richtung Zentrum verschoben sind;
• Fig. 5C Gesamtlichtverteilungen für bestimmte Öffnungswinkel, wobei sich die Gesamtlichtverteilung durch die Teillichtverteilungen aus Fig. 5A und 5B zusammensetzt;
• Fig. 6A erste Teillichtverteilungen für bestimmte Öffnungswinkel, wobei die Parameter des ersten Mikroscanners gemäß des erfindungsgemäßen Kriteriums eingestellt sind;
• Fig. 6B zweite Teillichtverteilungen für bestimmte Öffnungswinkel, wobei die Parameter des zweiten Mikroscanners gemäß des erfindungsgemäßen Kriteriums eingestellt sind;
• Fig. 6C Gesamtlichtverteilungen für bestimmte Öffnungswinkel, wobei sich die Gesamtlichtverteilung durch die Teillichtverteilungen aus Fig. 6A und 6B zusammensetzt;
• Fig. 6D Gesamtlichtverteilungen aus Fig. 6C für bestimmte Öffnungswinkel, wobei an den Rändern der jeweiligen Gesamtlichtverteilungen die entsprechenden Laserlichtquellen gedimmt sind.

The invention is explained in more detail below with reference to exemplary drawings. Here shows

• 1 an exemplary illumination system with a first laser scanner, which includes a first microscanner, and a second laser scanner, which includes a second microscanner, wherein the microscanners are each inclined by a first or a second angle, and wherein the microscanners have parameters that can be changed by a control device , wherein the first laser scanner generates a first partial light distribution and the second laser scanner generates a second partial light distribution, wherein the first and the second partial light distribution together generate an overall light distribution which has an aperture angle, the overall light distribution being imaged on a measuring screen,
• 2 an exemplary characteristic curve of a microscanner, where an oscillation amplitude AMP is plotted against the angular velocity, and where the maximum oscillation amplitude MEMSmax is 6°,
• Figure 3A a representation of a changed oscillation amplitude AMP of the characteristic 2 ;
• Figure 3B a representation of a light center shift LSVP on the characteristic 2 ;
• Figure 3C a representation of a shift in a characteristic by an offset value OFFSET;
• Figure 4A a representation of the first and second partial light distribution on the measuring screen for different opening angles, the first and the second angle of the respective microscanner being zero;
• Figure 4B a representation of the total light distribution on the measuring screen, which is made up of the partial light distributions Figure 4A composed;
• Figure 5A first partial light distributions for specific opening angles, with the first microscanner being inclined by 2° in this example, with the light center point being shifted towards the center for the individual partial light distributions shown;
• Figure 5B second partial light distributions for specific opening angles, with the second microscanner being inclined by -2° in this example, with the light center point being shifted towards the center for the individual partial light distributions shown;
• Figure 5C Overall light distribution for specific opening angles, with the overall light distribution being made up of the partial light distributions Figures 5A and 5B composed;
• Figure 6A first partial light distributions for specific opening angles, the parameters of the first microscanner being set according to the criterion according to the invention;
• Figure 6B second partial light distributions for specific opening angles, the parameters of the second microscanner being set according to the criterion according to the invention;
• Figure 6C Overall light distribution for specific opening angles, with the overall light distribution being made up of the partial light distributions Figures 6A and 6B composed;
• Figure 6D Total light distributions off Figure 6C for specific opening angles, with the corresponding laser light sources being dimmed at the edges of the respective total light distributions.

1 shows an exemplary lighting system 10 for a motor vehicle, which lighting system 10 comprises a first laser scanner 100 with at least one laser light source 110 , wherein the laser light source 110 is assigned a first microscanner 120 , which first microscanner 120 is set up to apply laser beams from the laser light source 110 to a first light conversion element 130 , whereby visible light is emitted at first light conversion element 130 and a first light image is generated, wherein first light conversion element 130 is assigned an optical imaging system 140 in order to image the first light image in front of illumination system 10 as a first partial light distribution 150 .

Furthermore, the illumination system 10 comprises a second laser scanner 200 with at least one laser light source 210 , the laser light source 210 being assigned a second microscanner 220 , which second microscanner 220 is set up to direct laser beams from the laser light source 210 onto a second light conversion element 230 , whereby visible light is emitted by the second light conversion element 230 and a second light image is generated, with the second light conversion element 230 being assigned an optical imaging system 240 in order to image the second light image in front of the illumination system 10 as a second partial light distribution 250 .

In this example, the first and the second microscanner are designed as quasi-static microscanners. 2 shows a diagram showing the different oscillation behavior of a resonant microscanner (dashed line) and a quasi-static microscanner (solid line).

The resonant microscanners essentially represent mechanical oscillating circuits that are excited at their resonant frequency and oscillate sinusoidally. This sinusoidal curve poses a major problem in terms of utilizing the installed laser power, since the light distribution is always brightest where the microscanner reaches the lowest angular velocity. In the case of a sinusoidal oscillation, the edge area would appear brightest and the middle area or the center of the light distribution would appear darkest, which is why the laser diodes have to be dimmed to a large extent and can therefore only be used to a small percentage.

This can be remedied by quasi-static microscanners, whose angular velocity can be controlled at will within certain physical limits. It is thus possible to direct a large part of the light generated into the middle or center of the partial light distribution, as a result of which the utilization of the installed laser power of the laser light sources can be increased. It should be noted that the microscanner changes direction in the edge area, which means that the mirror is completely "decelerated" and then accelerated in the opposite direction. During this phase, the laser light sources are deactivated, because otherwise the light intensity would increase significantly in this reversal area due to the low average angular velocity, which is not desirable.

The first and second partial light distributions 150 , 250 can be changed depending on at least three parameters that can be set on the respective microscanners 120 , 220 , namely AMP , LSPV and OFFSET , which are defined in Figures 3A , 3B and 3C are explanatory shown, with the variable first and second partial light distribution 150 , 250 generate a common variable total light distribution 300 in front of the lighting system 10 and at least partially overlap, the total light distribution 300 having an opening angle.

It should be noted that the partial light distributions 150 , 250 and the formed overall light distribution 300 in the example shown in the figures are imaged on a measuring screen MS, which is used, for example, in a lighting technology laboratory and is arranged perpendicular to a main emission direction of the laser scanner. A typical distance of such a measuring screen to the device to be measured is 25m according to ECE regulations.

The first and second microscanners 120 , 220 are each rotatably mounted about an axis X1 , X2 , which are arranged parallel to one another, with the first and second microscanners 120 , 220 about a zero position with a definable oscillation amplitude AMP about the respective axis X1 , X2 can oscillate, with the oscillation amplitude AMP being limited by a maximum value MEMSmax , with the oscillation amplitude AMP determining a horizontal width of the partial light distribution 150 , 250 generated in each case. The opening angle of the partial light distribution or the oscillation amplitude AMP of the microscanner can be changed dynamically (in fine gradations), whereby the brightness increases significantly due to the smaller illumination area, for example due to the speed-dependent increase in the illumination range. Figure 3A shows, for example, an oscillation amplitude AMP limited to +/-2°, where it can be seen that the angular velocity in the area of the zero position of the microscanner is lower than in the characteristic curve off 2 , resulting in increased light intensity.

The first and the second partial light distribution 150 , 250 each have a light focus, which is characterized in that the respective light intensity is maximum at this point, the light focus on the respective microscanners 120 , 220 corresponding to a fixable light focus shift LSPV being shiftable . As already explained above, the center of gravity of the light results from the deflection area of the microscanner with the lowest angular velocity (the edge areas or reversal points are excluded from this). Figure 3B shows a shift in the center of gravity of the characteristic curve 2 , whereby the microscanner moves the slowest in that area in which the center of the light is desired.

The partial light distributions 150 , 250 can each be shifted by an offset value OFFSET that can be supplied to the respective microscanners 120 , 220 , the mode of action of this parameter being explained as an explanation in Figure 3C is shown. The micro scanner parameter OFFSET allows to add an offset value to the angular movement of the specific micro scanner. In the chart off Figure 3C an example is shown with an offset value of 2° at a vibration amplitude of 4°. The light center shift LSPV is set to 0° here.

The illumination system 10 also includes a control device 400 , which is set up to control the first and the second microscanner 120 , 220 , the oscillation behavior of the first and second microscanner 120 , 220 at least via the parameters oscillation amplitude AMP , light center shift LSVP , and offset value OFFSET , which can be changed by the control device 400 can be controlled. The control device 400 is also set up to receive an input variable DOA that changes over time, which represents a target aperture angle of the overall light distribution 300 , and sets the parameters of the first and second microscanners 120 , 220 accordingly.

Also, the first and second micro scanners 120 , 220 are off 1 are arranged along an imaginary line, the zero position of the first microscanner 120 being inclined by a first angle ALPHA and the zero position of the second microscanner 220 being inclined by a second angle ALPHA 'to the imaginary line, the first and the second angle ALPHA , ALPHA ' being inverse to each other, for example the first angle ALPHA is 2° and the second angle ALPHA ' is -2°.

the Figure 4A 4B and 4B show diagrams of the partial light distributions and the resulting total light distributions for different DOA values, the first angle ALPHA and the second angle ALPHA being 0°, and symmetrical partial light distributions therefore occurring. A symmetrical light distribution exists when the center position of the partial light distribution also corresponds to the center position of the microscanner deflection.

It should be noted that the subsequent diagrams from Figures 4A to 6D show the relative light output, which is the reciprocal of the angular velocity of each corresponds to microscanners. The slower the microscanner is moved, the more light output is emitted in the area traversed. For this reason, the diagrams shown are always inversely proportional to the angular velocity of the respective microscanner.

It should also be noted that all diagrams are labeled with angle values. This representation is inevitably only correct for a certain projection distance, since the two laser scanners are, for example, one vehicle width apart. For example, this projection distance is 25m, as required by the ECE guidelines. However, this representation was chosen in order to create a better understanding.

In the Figure 4A The dotted line represents a DOA value of 6°, which corresponds to a partial light distribution of -6° to +6° on the measuring screen and represents the widest partial light distribution. The DOA value is usually shown as a "+" value, for example DOA =6°, but this always corresponds to a symmetrical illumination area of +/- 6°. With a reduction in the DOA value, the illumination area is reduced further and further, which means that the light output in the remaining angle range increases sharply. Since both laser scanners in this example Figures 4A and 4B cover an identical angular range in the resulting partial light distribution, the light output is doubled by superimposing the two partial light distributions, which in Figure 4B you can see.

An asymmetrical partial light distribution occurs when the middle position of the partial light distribution does not correspond to the middle position or the zero position of the microscanner deflection. This is the case if, for example, the respective microscanners are arranged rotated relative to one another by an angle. In the example shown below Figures 5A , 5B and 5C the first angle ALPHA is +2° and the second angle ALPHA ' is -2°. The center position of the partial light distribution is therefore shifted by 2° in each case. By twisting the microscanner, a horizontally broader basic light distribution is generated. In order to continue to obtain an area with the maximum light intensity in the center of the overall light distribution, the light focal points of the partial light distributions must be shifted back to the center. This is done via the LSPV parameter, which leaves the vibration amplitude of the microscanner unchanged, However, the area in which the microscanner oscillates the slowest is brought closer to the center of the overall light distribution or closer to the center on the measuring screen.

Figure 5A shows the first partial light distributions of the first laser scanner and Figure 5B second partial light distributions of the second laser scanner, several partial light distributions with different oscillation amplitudes or for different opening angles of the total light distribution (DOA value) being shown again. The figure shows that the center of light must always be adjusted for the various DOA values in such a way that the center of light remains in the middle of the overall light distribution. In practice, this is not possible with very low DOA values, since the center of light in conventional microscanner systems is limited to a certain percentage of the vibration amplitude of the microscanner.

It can be seen that the focal points of the light for the DOA values of 4 and 4.5° can no longer be shifted to the center. As already mentioned, this is due to the fact that the center of the light can only be shifted up to a maximum of approx. 80% of the oscillation amplitude.

Figure 5C shows a superimposition of the partial light distributions Figures 5A and 5B , where it can be seen that effects occur that are not desired, such as the double light centers at DOA = 8°. Furthermore, when the DOA values are reduced, not only do the outer edges or borders move inward, but rather both borders of the first and second microscanner. As a result, there are "moving" jumps in brightness within the light distribution when there is a change from DOA values.

• AMP = DOA
• OFFSET = ALPHA
• LSPV = 0°
  und die Parameter des zweiten Mikroscanners 220 wie folgt festlegt sind:
  • AMP = DOA
  • OFFSET = -ALPHA
  • LSPV = 0°
    und wobei bei Nichterfüllung des Kriteriums die Parameter des ersten Mikroscanners 120 wie folgt festgelegt sind: $$\mathbf{AMP}=\left(\mathbf{DOA}+\mathbf{MEMSmax}-\mathbf{ALPHA}\right)/2$$
    
    $$\mathbf{OFFSET}=\mathbf{MEMSmax}-\mathbf{AMP}$$
    
    $$\mathbf{LSPV}=\mathbf{DOA}-\mathbf{AMP}$$
    
    und die Parameter des zweiten Mikroscanners 220 wie folgt festgelegt sind: $$\mathbf{AMP}=\left(\mathbf{DOA}+\mathbf{MEMSmax}-\mathbf{ALPHA}\right)/2$$
    
    $$\mathbf{OFFSET}=-\left(\mathbf{MEMSmax}-\mathbf{AMP}\right)$$
    
    $$\mathbf{LSPV}=-\left(\mathbf{DOA}-\mathbf{AMP}\right).$$
    

In order to minimize or completely avoid these undesired effects, the control device 400 , which controls the first and the second microscanner 120 , 220 , is set up to receive an input variable DOA which changes over time and which represents a target opening angle of the overall light distribution 300 , and the parameters vibration amplitude AMP , light center shift LSPV and offset value OFFSET of the first and second microscanners 120 , 220 depending on the test result of a criterion of the input variable DOA , namely DOA ≤ ( MEMSmax - ALPHA ), with the maximum vibration amplitude MEMSmax den represents the maximum angle around the respective axis X1 , X2 , and where the parameters of the first microscanner 120 are defined as follows if the criterion is met:

• AMP = DOA
• OFFSET = ALPHA
• LSPV = 0°
  and the parameters of the second micro-scanner 220 are set as follows:
  • AMP = DOA
  • OFFSET = -ALPHA
  • LSPV = 0°
    and where if the criterion is not met, the parameters of the first microscanner 120 are defined as follows: $$\mathbf{AMP}=\left(\mathbf{DOA}+\mathbf{MEMS\; max}-\mathbf{ALPHA}\right)/2$$
    
    $$\mathbf{OFFSET}=\mathbf{MEMS\; max}-\mathbf{AMP}$$
    
    $$\mathbf{LSPV}=\mathbf{DOA}-\mathbf{AMP}$$
    
    and the parameters of the second micro-scanner 220 are set as follows: $$\mathbf{AMP}=\left(\mathbf{DOA}+\mathbf{MEMS\; max}-\mathbf{ALPHA}\right)/2$$
    
    $$\mathbf{OFFSET}=-\left(\mathbf{MEMS\; max}-\mathbf{AMP}\right)$$
    
    $$\mathbf{LSPV}=-\left(\mathbf{DOA}-\mathbf{AMP}\right).$$
    

In Figures 6A and 6B the first and second partial light distributions can be seen, with the above-mentioned algorithm for setting the parameters being used by the control device 400 .

In Figure 6A it can be seen that with high DOA values only the left cut-off of the partial light distribution is shifted inwards. At a DOA value of 4° (in this example) there is a transition to a symmetrical partial light distribution, whereby both the left and the right cut-off line move inward evenly. Figure 6B basically shows the first partial light distributions Figure 6A only mirrored.

Figure 6C shows the overlays of the partial light distributions Figures 6A and 6B for different DOA values.

In practice, the brightness profile of the partial light distributions or the basic light distributions that can be generated is not generated solely via the angular velocity of the microscanner, since this cannot generate any desired velocity profiles, but the laser light sources are additionally dimmed. This is particularly necessary in the edge area, since the microscanner has a limited maximum speed. In the reversal areas, which cannot be seen in the diagrams, the laser light source is switched off or deactivated completely. In this case, the control device 400 is set up to control the laser light sources accordingly. The curves shown above can be improved by additional dimming of the laser light sources in the "left" and "right" edge area, such as in Figure 6D be improved in terms of a smooth transition from light to dark.

Claims (8)

1. Lighting system (10) for a motor vehicle, which lighting system (10) comprises:

   - a first laser scanner (100) having at least one laser light source (110), the laser light source (110) having associated therewith a first microscanner (120), the first microscanner (120) being adapted to direct laser beams from the laser light source (110) to a first light converting element (130) whereby visible light is emitted at the first light conversion element (130) and a first light image is generated, wherein an optical imaging system (140) is associated with the first light conversion element (130) to image the first light image in front of the illumination system (10) as a first partial light distribution (150),

   - a second laser scanner (200) having at least one laser light source (210), the laser light source (210) being associated with a second microscanner (220), which second microscanner (220) is arranged to direct laser beams of the laser light source (210) onto a second light conversion element (230) whereby visible light is emitted at the second light conversion element (230) and a second light image is generated, wherein an optical imaging system (240) is associated with the second light conversion element (230) to image the second light image in front of the illumination system (10) as a second partial light distribution (250),

   wherein the first and the second partial light distribution (150, 250) are variable depending on at least three parameters (AMP, LSVP, OFFSET) adjustable at the respective microscanners (120, 220),

   wherein the variable first and second partial light distributions (150, 250) generate a common variable overall light distribution (300) in front of the illumination system (10) and at least partially overlap, wherein the overall light distribution (300) has an aperture angle,

   and wherein the first and the second microscanner (120, 220) are each rotatably mounted about an axis (X1, X2) which are arranged parallel to one another, wherein the first and the second microscanner (120, 220) can oscillate about a zero position with a fixable oscillation amplitude AMP about the respective axis (X1, X2), wherein the oscillation amplitude AMP is limited by a maximum value MEMSmax, wherein the oscillation amplitude AMP determines a horizontal width of the respectively generated partial light distribution (150, 250),

   and wherein the first and the second microscanner (120, 220) are arranged along an imaginary line, wherein the zero position of the first microscanner (120) is arranged inclined to the imaginary line by a first angle ALPHA and the zero position of the second microscanner (220) is arranged inclined to the imaginary line by a second angle ALPHA', wherein the first and the second angle ALPHA, ALPHA' are inverses of each other,

   and wherein the first and the second partial light distributions (150, 250) each have a center of light which is characterized in that the respective light intensity is maximum at this point, wherein the center of light at the respective microscanners (120, 220) can be shifted according to a definable center of light shift LSPV,

   and wherein the partial light distributions (150, 250) can each be shifted by an offset value OFFSET which can be supplied to the respective microscanners (120, 220),

   - a control device (400) which is set up to drive the first and the second microscanner (120, 220), it being possible to control the oscillation behavior of the first and second microscanner (120, 220) at least by means of the parameters oscillation amplitude AMP, center of gravity shift LSVP, and offset value OFFSET, which can be varied by the control device (400),

   characterized in that

   the control device (400) is arranged to receive a time-variable input variable DOA which represents a desired opening angle of the total light distribution (300), and to change the parameters oscillation amplitude AMP, center of light shift LSVP, and offset value OFFSET of the first and second microscanner (120, 220) depending on the test result of a criterion of the input quantity DOA, namely DOA ≤ (MEMSmax - ALPHA), where the maximum oscillation amplitude MEMSmax represents the maximum angle about the respective axis (X1, X2), and where, if the criterion is satisfied, the parameters of the first microscanner (120) are set as follows:

   AMP = DOA

   OFFSET = ALPHA

   LSPV = 0°

   and the parameters of the second microscanner (220) are set as follows:

   AMP = DOA

   OFFSET = -ALPHA

   LSPV = 0°

   and where, if the criterion is not met, the parameters of the first microscanner (120) are set as follows: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMSmax}-\mathrm{ALPHA}\right)/2$$

   

   $$\mathrm{OFFSET}=\mathrm{MEMSmax}-\mathrm{AMP}$$

   

   $$\mathrm{LSPV}=\mathrm{DOA}-\mathrm{AMP}$$

   

   and the parameters of the second microscanner (220) are set as follows: $$\mathrm{AMP}=\left(\mathrm{DOA}+\mathrm{MEMSmax}-\mathrm{ALPHA}\right)/2$$

   

   $$\mathrm{OFFSET}=-\left(\mathrm{MEMSmax}-\mathrm{AMP}\right)$$

   

   $$\mathrm{LSPV}=-\left(\mathrm{DOA}-\mathrm{AMP}\right).$$

   
2. Lighting system according to claim 1, characterized in that the laser light sources (110, 210) are dimmable.
3. Lighting system according to claim 1 or 2, characterized in that measured from the imaginary line the first angle ALPHA is 2° and the second angle ALPHA' is -2°.
4. Lighting system according to any one of claims 1 to 3, characterized in that the microscanners (120, 220) are designed as quasi-static microscanners.
5. Lighting system according to any one of claims 1 to 4, characterized in that the maximum value MEMSmax of the vibration amplitude AMP of the microscanners (120, 220) is 6°.
6. Lighting system according to any one of claims 1 to 5, characterized in that the control device (400) drives the laser light sources (110, 210).
7. Motor vehicle having at least one lighting system (10) according to any one of claims 1 to 6.
8. Motor vehicle according to claim 7, characterized in that the time-variable desired opening angle of the overall light distribution DOA changes as a function of the speed of the motor vehicle, the desired opening angle DOA being reduced when the speed of the motor vehicle increases.

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