DE102016102456A1 - Lighting device for vehicles - Google Patents

Abstract

The invention relates to a lighting device for vehicles with a laser-based light source unit for emitting laser light in a predetermined beam angle and with an optical unit for generating a light distribution, wherein a Teilstrahlumlenkungseinrichtung is provided by means of which a main beam in a main beam direction for generating the light distribution can be forwarded and by means of which a partial beam from a beam path of the main beam can be deflected at an angle to the main beam fed to a sensor detecting the position of the partial beam, so that a change in the emission angle of the main beam can be determined as a function of the detected position of the partial beam.

Description

The invention relates to a lighting device for vehicles with a laser-based light source unit for emitting laser light in a predetermined beam angle and with an optical unit for generating a light distribution.

From the DE 10 2012 100 141 A1 a lighting device for vehicles with a laser-based light source unit and an optical unit for generating a predetermined light distribution is known. The light source unit has a laser light source for emitting a primary beam and a conversion element for converting the primary beam into a relatively broadband secondary beam of white light color. Such laser-based light source units have a relatively large range compared to, for example, LED-based light source units. For the operation of such laser-based light source units, it is important that the emitted from the laser light source primary beam with only slight deviations in a given direction, since even small changes in direction of the primary beam would lead to a relatively large shift in the light distribution, which affects the operation of the lighting device. So that the current direction of the primary beam can be determined is from the DE 10 2012 105 966 A1 a position sensor is known, which could determine the position or rotation of the laser beam generating laser light source in an inductive manner. There is thus an indirect measurement of a change in direction of the laser beam emitted by the laser light source. Due to the mechanically moving parts of this sensor, the cost is relatively large.

The object of the present invention is to further develop a lighting device for vehicles with a laser-based light source unit such that the outlay for determining a radiation angle of the laser-based light source unit is reduced in a simple manner.

To solve this problem, the invention in conjunction with the preamble of claim 1, characterized in that a Teilstrahlumlenkungseinrichtung is provided by means of which a main beam in a main beam direction for generating the light distribution can be forwarded and by means of which a partial beam from a beam path of the main beam deflected in a Angle to the main beam to the position of the sub-beam detecting sensor can be supplied, so that a change in the emission angle of the main beam can be determined depending on the detected position of the sub-beam.

According to the invention, a Teilstrahlumlenkungseinrichtung is provided by means of which a division of the laser beam impinging on them takes place in a main beam, which is forwarded in a main emission direction for generating the light distribution, and in a partial beam which is deflected at an angle to the main beam in the partial beam direction. Furthermore, the illumination device according to the invention has a sensor which detects the partial beam, so that it is possible to deduce a direction and in particular a change in direction of the partial beam on the basis of the determined position, with which ultimately the current emission angle and in particular a change in the emission angle can be inferred the main beam extends in the main emission direction. In particular, a change in the emission angle of the main beam can thus be detected in a simple and reliable manner in order to initiate corrective measures, if necessary. The invention thus allows a direct measurement of a possible beam offset of the main beam, so that a secure and accurate determination of the current direction of the main beam is ensured.

According to a preferred embodiment of the invention, the partial beam deflection device is designed such that the partial beam extends to the main beam at a fixed predetermined partial beam angle. If the beam angle of the main beam changes, the beam angle of the sub-beam also changes. The quotient of the change in the direction of the main beam and the change in direction of the partial beam is preferably constant. Advantageously, it can thus be concluded from a change in direction of the partial beam on the change in direction of the main beam, so that subsequently compensatory control measures of the light source unit can be made.

According to a development of the invention, a change in the partial beam angle of the partial beam to the main beam is dependent on a material of the partial beam deflection device or on a control signal acting on the material of the partial beam deflection device. The property of the material of the partial beam deflection device, which may optionally be excited externally by means of a control signal, is responsible for the magnitude of the change of the partial beam angle in response to a change in the main beam angle. Since the emission angle of the partial beam or the partial beam angle is functionally dependent on the emission angle of the main beam or vice versa, it is possible to deduce the actual change in the emission angle of the main beam. Advantageously, the sensitivity of the sensor can thereby be preset.

According to a development of the invention, the partial beam deflection device is a Beam splitter and / or designed as a beam direction modulating optical device. Advantageously, the partial beam can thereby be "branched off" without the main beam being influenced. In particular, this does not change the direction of the main beam, whose emission angle coincides with the angle of the beam incident in the partial beam deflection device.

According to a development of the invention, the beam direction-modulating optical component is designed as an optical modulator with a material whose refractive index can be changed and / or adjusted by means of the control signal acting on it. For example, a beam can be used to determine the direction of the main beam.

According to a development of the invention, the beam direction-modulating optical component is designed as an acousto-optic modulator, wherein a beam diffracted by the modulator serves for a secondary order or a beam reflected by the modulator as partial beam. The excitation of the acousto-optic modulator takes place acoustically, so that the effort can be reduced. The acoustic excitation forms in the material of the acousto-optical modulator a periodic modulation of the refractive index, which acts on the laser beam like an optical grating and causes a diffraction of the beam.

According to a development of the invention, the partial radiation deflection device is formed by a conversion element which serves to convert the monochromatic primary beam emitted by the laser light source into a secondary beam of white light color. On the conversion element of the point-shaped primary beam is directed so that a light spot is formed on the conversion element. In the direction of passage of the primary beam, the secondary beam is formed. In the opposite direction to the direction of passage of the partial beam is emitted. For example, this may be light scattered on the conversion element. Advantageously, no additional control measures are required. Accordingly, an optical component (conversion element) provided for another optical function can additionally be used for the detection of the main beam.

A beam widening optical system is arranged between the partial beam deflection device and the sensor, so that adaptation to the surface of the sensor can take place. Alternatively or additionally, an optical element may be provided for imaging the partial beam onto the sensor.

According to a development of the invention, the sensor is designed as an electronic multi-capacitor detector, which is formed as a CCD chip or from a number of CMOS chips or consists of only a limited number of photosensitive diodes. It can thereby be determined beam offsets with very high accuracy. Photosensitive diodes leads to a particularly cost-effective design of the sensor.

According to a development of the invention, the sensor is designed as an electronic-analog-optical position-sensing detector (PSD). An analog position-sensing detector (PSD) is a particularly cost-effective solution for determining position. However, a discrete optical position-sensitive detector can be used.

If a control device is provided so that a difference between an actual direction and a desired direction of the main beam can be minimized as a function of a sensor signal generated by the sensor, a correction of the main beam direction is quickly brought about. The correction can be done by control and / or regulation.

Embodiments of the invention are explained below with reference to the drawings.

Show it:

1 a schematic representation of a lighting device according to a first embodiment,

2 a schematic representation of the lighting device according to a second embodiment,

3 a schematic representation of the lighting device according to a third embodiment,

4 a schematic representation of the lighting device according to a fourth embodiment,

5a a top view of a four-quadrant detector, on which a partial beam impinges in the normal operating state of the lighting device,

5b a top view of the four-quadrant detector on which the partial beam impinges in the deflected state,

6a a plan view of an analog position-sensitive detector (PSD), which is incident on the partial beam in the deflected state, and

6b a side view of the analog position-sensitive detector (PSD) on which the sub-beam impinges in the deflected state.

An illumination device according to the invention for vehicles is preferably used in headlamps for generating a predetermined light distribution, for example a dynamic high beam and / or low beam distribution.

According to a first embodiment of the invention according to 1 the lighting device has a laser-based light source unit 1 on, the laser light or a laser beam 2 in the direction of an optical unit 3 radiates. The optical unit 3 serves to generate a given light distribution. Between the light source unit 1 and the optical unit 3 is an optical element 6 for changing the direction of the laser beam 2 intended. In the direction of radiation in front of the optical element 6 that is, between the optical element 6 and the optical unit 3 is a partial beam deflection device 4 arranged, from which a main ray 5 without change of direction in Hauptabstrahlrichtung to the optical unit 3 is passed through and from a partial beam 7 forming a partial beam angle φ _T to the main beam 5 is deflected in partial beam direction to a sensor 9 , In the present embodiment, the partial beam angle φ _T 90. ° The geometric arrangement is not limited to this angular arrangement. It depends essentially on the nature of the Teilstrahlumlenkungseinrichtung 4 and is preferably to be chosen so that the optimal performance of the Teilstrahlumlenkungseinrichtung 4 is reached. The beam angle of the main beam 5 agrees with the radiation angle of the partial beam deflection device 4 incident laser beam 2 match. The partial beam 7 has an emission angle that coincides with the partial beam angle φ _T.

, wobei I₁, I₂, I₃ und I₄ den elektrischen Strömen in den jeweiligen Quadranten 10, 11, 12, 13 nach einer Linearisierung durch die Auswerteelektronik des Sensors 9 entsprechen. Die Linearisierung der Ströme I₁, I₂, I₃ und I₄ kann notwendig sein, wenn der Hauptstrahl 5 – wie hier – eine nichtlineare gaußförmige Intensitätsverteilung aufweist. The partial beam deflection device 4 is formed as a beam splitter which detects the incoming laser beam 2 in the main beam 5 and the sub-beam 7 divides. In the beam path of the sub-beam 7 there is a beam expansion optics 8th , so that the sub-beam 7 to the sensor 9 can be adjusted. The sensor 9 is formed as a four-quadrant detector having a plurality of photodiodes or a CCD chip or a C-mos chip. The four-quadrant detector (multi-quadrant detector) 9 is in four quadrants 10 . 11 . 12 . 13 divided up. In the normal operating state of the lighting device, the partial beam hits 7 to the center of the four-quadrant detector 9 , being a point of light 14 is formed, with its four equal-sized circular cutouts 14 ' . 14 '' . 14 ''' . 14 ^IV equal areas of the quadrant 10 . 11 . 12 . 13 illuminated. In a Cartesian coordinate system with an x-axis and a y-axis, the coordinates of the light point can be defined 14 determine as follows:

where I ₁ , I ₂ , I ₃ and I _{4 are} the electrical currents in the respective quadrants 10 . 11 . 12 . 13 after a linearization by the transmitter of the sensor 9 correspond. The linearization of the currents I ₁ , I ₂ , I ₃ and I ₄ may be necessary when the main beam 5 - As shown here - has a non-linear Gaussian intensity distribution.

Occurs due to a disturbance of the lighting device, a change in direction of the main beam 5 on, takes place with change of the main beam 5 due to the functional angular relationship to the sub-beam 7 a change in position of the partial beam 7 , as can be seen from the change in position of the light spot 14 on the four-quadrant sensor 9 corresponding 5b results. The partial beam angle φ _T can be constant here, for example. The current I ₁ in the first quadrant 10 and the respective currents I ₂ , I ₃ and I ₄ in the corresponding other quadrants 11 . 12 and 13 have a different amount than in the normal operating condition according to 5a , According to 5b will be in the first quadrant 10 a larger current I ₁ than the currents I ₂ , I ₃ and I ₄ . In the third quadrant, the current I3 is generated, which is comparatively low compared to the other currents I ₁ , I ₂ and I _{4 of} the other quadrants. In the different current heights in the quadrants 10 . 11 . 12 and 13 can be the position shift of the sub-beam 7 in the direction of an angle bisector of the first quadrant 10 determine. The sensor 9 generates the position or the position change of the laser point 14 representative sensor signal which is transmitted to a control device, not shown. The control device acts on the light source unit 1 such that a difference between the predetermined desired direction of the main beam 5 is minimized to a current actual direction of the same. Ideally, the deviation between the desired direction and the actual direction of the main beam 5 reduced to zero.

According to an alternative embodiment of the invention, the sensor is designed as an analog optical position-sensitive detector PSD. The basic operation of such an analog optical position-sensitive detector PSD corresponds to that of a photodiode in which, instead of a peripheral surface contact, a plurality of contacts are connected at the edges. A photodiode, preferably in elongated design, with anode electrodes on the front sides and a cathode electrode on the bottom, z. B. for Realization of a one-dimensional position-sensitive detector PSD can be used. By a light spot incident on the position-sensitive detector PSD, a photocurrent is generated which, according to Kirchhoff's rules, is divided between the two anodes. The track resistances in the photoactive area of the sensor PSD are proportional to the length of the distance covered in each case. The position is determined by measuring the currents flowing in the anodes I ₁ and I ₂ . If the origin of the coordinates is in the middle of the sensor PSD, the position can be determined using the following formula:

I_x1, I_x2

– die Ströme in die Anoden,

L_x

– die Länge der photoaktiven Fläche resp. des Sensors, und

X

– die Position des Lichtspots ausgehende von der Mitte des Sensors.

Here are:

I _x1 , I _x2

- the currents into the anodes,

L _x

- The length of the photoactive surface resp. of the sensor, and

X

- The position of the light spot emanating from the center of the sensor.

The sum of the currents allows the intensity of the light to be determined.

In the case of a two-dimensional proof of the position of the light spot 50 the sensor PSD has four or five electrodes. The exact number of electrodes depends on the exact sensor design. Preferably, the sensor element PSD is square or rectangular, with an electrode on each side of the sensor PSD. The in 6a and 6b illustrated analog sensor PSD has four electrodes, a first x1 anode 51 a second x2 anode disposed on the same on an opposite side of the sensor PSD 52 , a first y1 cathode disposed on another side of the sensor PSD 53 and a second Y2 cathode disposed on the same opposite side of the sensor PSD 54 , In an alternative embodiment of the sensor PSD are each two electrodes (x1 anode 51 and x2 anode 52 ) on one top and two electrodes (y1 cathode 53 and Y2 cathode 54 ) is mounted on the underside of the PSD sensor. About the currents in the electrodes 51 . 52 . 53 . 54 can both the position and the light intensity of the sub-beam 50 be determined. For the two-dimensional position determination, the above equation is supplemented by the y-component:

I_x1, I_x2

– die Ströme in die Anoden,

I_y1, I_y2

– die Ströme in die Kathoden,

L_y

– die Länge der photoaktiven Fläche resp. des Sensors PSD, und

Y

– die Position des Lichtspots 50 ausgehende von der Mitte des Sensors PSD.

Here are:

I _x1 , I _x2

- the currents into the anodes,

I _y1 , I _y2

- the currents in the cathodes,

L _y

- The length of the photoactive surface resp. of the sensor PSD, and

Y

- the position of the light spot 50 outgoing from the center of the sensor PSD.

According to an alternative embodiment of the sensor, the sensor may also be designed as a discrete optical position-sensing detector.

Alternatively, the action on the light source unit 1 also be effected by means of a controller without a controller. The functional dependence between the beam angle of the sub-beam 7 and the main beam 5 allows the conclusion to the actual direction of the main beam 5 from the measured actual direction of the partial beam 7 ,

A lighting device according to 2 has a light source unit 21 on, which is a laser light source 22 with integrated modulator for changing the direction of a primary beam 25 , a mirror 23 as well as a conversion element 24 having. The laser light source 22 emits a monochromatic primary beam 25 , for example, blue light color from the mirror 23 in the direction of the conversion element 24 is reflected. In the conversion element 24 a conversion of the primary beam took place 25 in a secondary beam 26 which has a white light color. For this purpose, the conversion element 24 a phosphor material containing the primary beam 25 partially converted into light yellow color, so that by additive superposition of a yellow and blue light component of the broadband secondary beam 26 is formed. The of the conversion element 24 radiated secondary radiation 26 meets an optical unit 28 , by means of which the light distribution is generated.

In the present embodiment, the optical modulator allows the laser light source 22 the radiating of primary rays 25 . 25 ' . 25 '' in different directions. The primary rays 25 . 25 ' . 25 '' lead to differently arranged points of light 35 . 36 . 37 on the conversion element 24 , Accordingly, secondary rays or secondary radiation 26 . 26 ' . 26 '' emitted in different directions, so that, for example, a cornering light function or a headlight range control can be done when the light source unit 22 is controlled accordingly. The material of the optical modulator can be acted upon by a control signal, wherein the refractive index or a refractive index modulation of the material is variable as a function of the amplitude and / or the frequency of the control signal.

beamsplitter 32 . 33 . 34 can at different points of the lighting device for deflecting partial beams 29 . 30 respectively. 31 be arranged. Is the beam splitter 32 between the laser light source 22 and the mirror 23 arranged, meets the partial beam 29 on the sensor 9 placed in an area between the laser light source 22 and the mirror 23 is arranged. In an alternative embodiment of the invention, the beam splitter 33 between the mirror 23 and the conversion element 24 arranged so that the partial beam 30 on the sensor 9 that hits in an area between the mirror 23 and the conversion element 24 is arranged. In an alternative alternative variant of the illumination device, the beam splitter 34 in the direction of radiation in front of the optical unit 28 arranged so that the partial beam 31 on the sensor 9 that hits near the optical unit 28 is arranged.

In a third embodiment of the lighting device according to 3 goes from one to the lighting device 2 assumed identical basic structure of the lighting device. The same components or component functions are provided with the same reference numerals.

In the lighting device according to 3 no separate Teilstrahlumlenkungseinrichtung is provided. Instead, the conversion element points 24 a double function. On the one hand serves the conversion element 24 for converting the primary beam 25 . 25 ' . 25 '' in the secondary beam 26 . 26 ' . 26 '' , On the other hand, the points of light 35 . 36 . 37 the conversion element 24 used, a partial beam 39 against the passage direction 27 in the direction of the sensor 9 radiate. Preferably located between the conversion element 24 and the sensor 9 one as a lens 40 trained optical element for imaging the conversion element 24 or the light spot 35 . 36 . 37 on the multi-quadrant detector 9 , The conversion element 24 thus serves as Teilstrahlumlenkungseinrichtung whose emitted partial radiation 39 for determining the change in direction of the secondary beams 26 . 26 ' . 26 '' serve, as already described above.

According to a fourth embodiment of the invention according to 4 is a partial beam deflection device 41 as a beam direction modulating optical component, in particular as an acousto-optical modulator. The beam direction modulating optical component 41 gives a main beam 22 high intensity and one at a partial beam angle φ _T to the main beam 22 extending partial beam 43 low intensity. The acousto-optic modulator 41 consists of a crystal material with a diffraction grating, which is variable as a function of a frequency and / or one of an acoustic excitation signal. For the sub-beam 43 Preferably, a secondary order of the emitted radiation is used.

LIST OF REFERENCE NUMBERS

1

Light source unit

2

laser beam

3

optical element

4

Part beam deflection device

5

main beam

6

optical unit

7

partial beam

8th

Beam expander

9

sensor

10

quadrant

11

quadrant

12

quadrant

13

quadrant

14, 14 ', 14' ', 14' ''

 circular cutouts

21

Light source unit

22

Laser light source

23

mirror

24

conversion element

25, 25 ', 25' '

primary beam

26, 26 ', 26' '

secondary beam

27

Passage direction

28

optical unit

29

partial beam

30

partial beam

31

partial beam

32

beamsplitter

33

beamsplitter

34

beamsplitter

35

light spot

36

light spot

37

light spot

39

partial beam

40

lens

41

Part beam deflection device

42

main beam

43

partial beam

51

x1 anode

52

x2 anode

53

y1 cathode

54

y2 cathode

55

partial beam

PSD

Position-sensing sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012100141 A1 [0002]
• DE 102012105966 A1 [0002]

Claims (11)

Lighting device for vehicles with a laser-based light source unit ( 1 . 21 ) for the emission of laser light in a predetermined beam angle and with an optical unit ( 3 ) for producing a light distribution, characterized in that a partial beam deflection device ( 4 . 32 . 33 . 34 . 41 ) is provided, by means of which a main jet ( 5 ) can be forwarded in a main beam direction for generating the light distribution and by means of which a partial beam ( 7 ) from a beam path of the main beam ( 5 ) deflectable at an angle (φ _T ) to the main jet ( 5 ) one the position of the sub-beam ( 7 ) detecting sensor ( 9 ) can be supplied, so that by means of the detected position of the sub-beam ( 7 ) a change in the radiation angle of the main beam ( 5 ) can be determined. Lighting device according to claim 1, characterized in that the partial beam deflection device ( 4 . 32 . 33 . 34 . 41 ) is formed such that the partial beam ( 7 ) to the main jet ( 5 ) runs in a fixed predetermined angular ratio. Lighting device according to claim 2, characterized in that a change of a partial beam angle (φ _T ) of the partial beam ( 7 ) depending on a material of the partial beam deflection device ( 4 . 32 . 33 . 34 . 41 ) or depending on one on the material of the Teilstrahlumlenkungseinrichtung ( 4 . 32 . 33 . 34 . 41 ) and a direction of the sub-beam ( 7 ) is predetermining control signal. Lighting device according to one of claims 1 to 3, characterized in that the Teilstrahlumlenkungseinrichtung ( 4 . 32 . 33 . 34 . 41 ) as a beam splitter ( 4 . 32 . 33 . 34 ) and / or as a beam direction modulating optical component ( 41 ) is trained. Lighting device according to claim 4, characterized in that the beam direction modulating optical component ( 41 ) is formed as an optical modulator with a material whose refractive index is variable and / or adjustable by means of the control signal acting on the same. Lighting device according to claim 4 or 5, characterized in that the beam direction modulating optical component as an acousto-optic modulator ( 41 ), wherein a diffracted beam of a secondary order or a reflected beam as a partial beam ( 43 ) serves. Lighting device according to one of claims 1 to 6, characterized in that - the Teilstrahlumlenkungseinrichtung by a conversion element ( 24 ) is formed on the one of a laser light source ( 22 ) radiated monochromatic primary beam ( 25 . 25 ' . 25 '' ) as a point of light ( 35 . 36 . 37 ) and that the primary beam ( 25 . 25 ' . 25 '' ) into a secondary jet ( 26 . 26 ' . 26 '' ) converted white light color, which as the main beam in the direction of the optical unit ( 28 ), and - the sensor ( 9 ) at such an angle to the conversion element ( 24 ) is arranged, that by means of one of the light point ( 35 . 36 . 37 ) emitted partial beam ( 39 ) a change in position of the arranged on the conversion element light spot ( 35 . 36 . 37 ) can be determined. Lighting device according to one of claims 1 to 7, characterized in that between the Teilstrahlumlenkungseinrichtung ( 4 . 24 . 32 . 33 . 34 . 41 ) and the sensor ( 9 ) an optical element ( 8th ) for adapting the sub-beam ( 7 . 39 ) and / or for imaging the sub-beam ( 7 . 39 ) on the sensor ( 9 ) is arranged. Lighting device according to one of claims 1 to 8, characterized in that the sensor ( 9 ) is designed as an electronic multiquadrant detector. Lighting device according to one of claims 1 to 8, characterized in that the sensor ( 9 ) is designed as an analog or discrete optical position-sensing detector (PSD). Lighting device according to one of claims 1 to 10, that a control device is provided, with which the light source unit ( 1 . 21 ) depending on a the actual direction of the main beam ( 5 . 25 . 25 ' . 25 '' . 42 ) and detected by the sensor ( 9 ) is controllable and / or controllable such that a difference between a desired direction of the main beam ( 5 . 25 . 25 ' . 25 '' ) and the actual direction of the main beam ( 5 . 25 . 25 ' . 25 '' ) is reduced and / or led to zero.

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