• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A headlamp for vehicles, with at least one modulated laser diode (DL) whose laser beam can be steered by means of a light scanner to a light conversion means to generate at this a light image (11) which is projected via an imaging system as a light image on the road, and with a laser drive and a computing unit assigned to it, which supplies a modulation signal (sM) for the laser control, wherein the laser drive for the at least one laser diode (DL) has a regulated power supply (15) for the laser diode, the laser diode branch (Z) from a regulated one Parallel circuit (P) is bridged, which is designed as a current regulator with an analog controller (16, T2) and the modulation signal (sM) is supplied to the analog controller.
    公开号:AT517256A1
    申请号:T50444/2015
    申请日:2015-06-01
    公开日:2016-12-15
    发明作者:Weber Emanuel
    申请人:Zkw Group Gmbh；
    IPC主号:
    专利说明:

    Lighting device for vehicles
    The invention relates to a lighting device for vehicles, which has at least one LED branch with at least one LED, and with an LED drive and a computing unit, which supplies a drive signal for the LED drive, and with a regulated power supply for the LED control.
    The advent of automotive-based laser diode lighting systems requires ever higher diode current modulation speeds, with high-frequency control being required for this modulation. Conventional DC-DC converters used for LED driving are no longer operational at modulation frequencies in the MHz range, so for applications with such high switching frequencies a special, fast current control or control must be provided. One possible embodiment is an upstream "slow" DC-DC converter (eg boost) with a subsequent analog linear stage. However, such a downstream linear stage leads to an uneven loading of the DC-DC converter and to a permanent power loss.
    An object of the invention is to provide a headlamp which uses a modulated and scanning laser beam produced by light-emitting diodes, in particular by laser diodes, and in which no high losses occur, resulting not only in an increased heat load but also at a high cost because of the required Lead sizing. In particular, the voltage supply of the laser diode (s), for example, a DC-DC converter as evenly as possible, be charged independently of the modulation processes.
    The above object is achieved with a headlight of the type mentioned, in which according to the invention the LED branch is bridged by a regulated parallel circuit, which is designed as a current regulator with an analog controller and the drive signal is supplied to the analog controller.
    Thanks to the invention, a more uniform load, in particular the passive components, and a stable operating point setting is ensured. Also, costs and space can be saved by a smaller dimensioning of the output capacitors of the power supply.
    It is particularly preferred and advantageous if the illumination device is designed as a headlamp with at least one modulated laser diode in the LED branch whose laser beam can be directed to a light conversion means by means of a light scanner in order to generate a luminous image thereon, which is illuminated via an imaging system as a light image is projected onto the roadway, as well as with a laser diode drive and a processing unit associated therewith, which supplies as a drive signal, a modulation signal for the Laseransteue- tion
    An advantageous, since simple and inexpensive embodiment of the invention is characterized in that the analog controller has an operational amplifier and a transistor controlled by this.
    In a practical and economical variant, the analog controller is supplied as a control variable proportional to the current through the diode branch signal.
    The realization of a traffic-related skip scenario can be facilitated if a resistor through which the branched current flows is arranged in the parallel circuit.
    It is also useful if the power supply is a DC-DC converter.
    It is advantageous if the power supply is regulated to maximum load current.
    In many cases, it is useful if the power supply is a boost converter.
    The invention together with further advantages is explained in more detail below by way of example embodiments, which are illustrated in the drawing. In this show
    1 shows the basic structure of a headlamp, which uses a scanning, modulated laser beam,
    Fig. 2 shows an example circuit arrangement for driving a modulated laser in a headlamp according to the invention and
    Fig. 3 shows a further embodiment of a circuit arrangement for driving a modulated laser in a headlamp according to the invention.
    In Fig. 1, the important parts for a headlamp according to the invention are shown, it being understood that a motor vehicle headlamp still contains many other parts that allow its meaningful use in a motor vehicle, in particular a car or motorcycle. Lichttechnischer starting point of the headlamp is a laser light source 1, which emits a laser beam 2, and which is associated with a laser driver 3, said control 3 for power supply and for monitoring the laser emission or z. B. is used for temperature control and is also set up to modulate the intensity of the emitted laser beam. By "modulating" in the context of the present invention is meant that the intensity of the laser light source can be changed, be it continuous or pulsed, in the sense of switching on and off. It is essential that the light output can be changed dynamically analogously, depending on the angular position at which a mirror described in more detail later stands. In addition, there is still the possibility of switching on and off for a certain time, not to illuminate or hide defined places. An example of a dynamic drive concept for generating an image by a scanning laser beam is described, for example, in Applicant's document A 514633.
    The laser light source often contains several laser diodes in practice, for example, six of z. B. each 1 watt to achieve the desired power or the required luminous flux.
    The drive signal of the laser light source 1 is designated Us.
    The laser driver 3 in turn receives signals from a central processing unit 4, which sensor signals si ... Si ... sn can be supplied. These signals, for which a modulation signal sm is represented in FIG. 1 by way of example, can be, for example, switching commands for switching from high beam to low beam or signals recorded, for example, by sensors Si ... Sn, such as cameras, which determine the illumination conditions, environmental conditions and / or objects on the roadway. Also, the
    Signals originate from vehicle-vehicle communication information. The arithmetic unit 4 drawn here schematically as a block can be contained completely or partially in the headlight and serves in particular also for carrying out the method of the invention described below.
    The laser light source 1 emits, for example, blue or UV light, wherein the laser light source is followed by a collimator optics 5 and a focusing optics 6. The design of the optics depends, inter alia, on the type, number and spatial placement of the laser diodes used, on the required beam quality and on the desired laser spot size at the light conversion means.
    The focused or formed laser beam 2 'passes to a light scanner 7 and is reflected by a micromirror 10 onto a light conversion means 8, which in the present example is designed as a light-emitting surface, which is used e.g. has a phosphor for light conversion in a known manner. For example, the phosphor converts blue or UV light into "white" light. In the context of the present invention, "phosphorus" is generally understood to mean a substance or a substance mixture which converts light of one wavelength into light of another wavelength or of a wavelength mixture, in particular into "white" light, which can be subsumed under the term "wavelength conversion" is.
    One uses luminescent dyes, wherein the output wavelength is generally shorter and thus more energetic than the emitted wavelength mixture. The desired white light impression is created by additive color mixing. In this case, "white light" is understood as meaning light of such a spectral composition which causes the color impression "white" in humans. Of course, the term "light" is not limited to radiation visible to the human eye.
    It should be noted at this point that in the drawing, the light conversion means is shown as a phosphor surface on which the scanning laser beam or scanning laser beams produce an image projected from this side of the phosphor. However, it is also possible to use a translucent phosphor in which the laser beam, coming from the side facing away from the projection lens, produces an image, but the emission side is on the projection lens-facing side of the light conversion means. Thus, both reflective and transmissive beam paths are possible, and ultimately a mixture of reflective and transmissive beam paths is not excluded.
    The micromirror 10 oscillating about two axes in the present example is driven by a mirror drive 9 with the aid of drive signals ax, ay and e.g. deflected in two mutually orthogonal directions x, y. The mirror drive 9 is also controlled by the arithmetic unit 4 in order to be able to set the oscillation amplitudes of the micromirror 10 as well as its instantaneous angular velocity, wherein asymmetrical oscillation about the respective axis can also be adjustable. The driving of micromirrors is known and can be done in many ways, e.g. electrostatic, electromagnetic or electrodynamic. The position of the micromirror 10 is expediently confirmed by means of a position signal pr to the mirror drive 9 and / or to the arithmetic unit 4. It should be noted that other beam deflecting means, such as e.g. movable prisms, although the use of a micromirror is preferred.
    The laser beam 2 'thus scans across the light conversion means 8, which is generally flat, but need not be flat, and produces a light image 11 with a predetermined light distribution. This light image 11 is now projected onto the roadway 13 with an imaging system 12 as a light image 11 '. In this case, the laser light source is pulsed at high frequency or driven continuously, so that according to the position of the micromirror arbitrary light distributions are not only adjustable - for example, high beam / low beam - but are also quickly changeable, if this requires a special terrain or road situation, such as pedestrians or Oncoming vehicles are detected by one or more of the sensors Si .. .Sn and accordingly a change in the geometry and / or intensity of the light image 11 'of the road illumination is desired. The imaging system 12 is shown here in simplified form as a lens.
    The term "roadway" is used here for a simplified representation, because of course it depends on the local conditions whether the photograph 11 'is actually located on the roadway or extends beyond it. "In principle, the image 11' corresponds to a projection onto a vertical one Area in accordance with the relevant standards relating to automotive lighting technology.
    The circuit arrangement shown in Fig. 2 for a lighting device or a headlamp according to the invention essentially describes the structure of the laser driver 3 contained in Fig. 1 and shows a voltage source Ue, which is for example the accumulator of a motor vehicle, wherein in In the present case of this voltage source Ue a boost converter 15 is arranged downstream, in which only schematically a choke L, a switching transistor TI, a rectifier diode Dl and a capacitor C are shown. This boost converter supplies an output voltage Ua, which supplies a branch Z with at least one laser diode D1 via a sensor resistor Rs. It should be understood that neither the presence of a boost converter (or buck converter) is required and that the laser diode branch Z includes a number of laser diodes adapted to the supply voltage, in the simplest case a single laser diode.
    It should be noted at this point that although the invention offers particular advantages in a headlamp based on scanning laser beams, but also in other lighting devices for vehicles, such as direction indicators, which LEDs, light-emitting diodes or laser diodes - summarized here under the term LED - Are controlled by a diode drive, which receives a drive signal from a computing unit.
    According to the invention, a controlled parallel circuit is now arranged parallel to the laser diode branch Z, which is designed as an analog, preferably linear current regulator and in the present case a parallel to the branch Z lying transistor T2, e.g. Of the total, supplied by the power supply, here the step-up converter 15, the current Ig flows through a part of the laser diode branch Z as current Id and a part on the parallel branch as a current flows U, here via the transistor T2. The transistor T2 is driven by an operational amplifier 16, to which the following quantities are supplied: on the one hand as a control variable Urs, a current Id in the laser diode branch Z proportional, occurring at the resistor Rs voltage Urs and on the other hand, the modulation signal sm.
    The power supply 15, here the boost converter, regulates to the maximum current, wherein in full load operation, i. at maximum current at the analog controller, namely at T2, essentially no power loss occurs. In the case of a high-frequency modulation of the current of the laser diode (s) D1, a signal is applied via the parallel circuit of the analog regulator via the transistor T2
    Stream Ib diverted, so that the output current Ig of the power supply remains constant and a uniform load on the power supply 15, here the boost converter, is ensured.
    Modulating is understood to be any influencing of the current through the laser diode D 1 (or laser diodes), also a so-called "dimming", which is necessary in order to provide the required optical powers in the respective image in the light image or, for example, by a traffic-dependent skimming scenario to realize that is much more critical in terms of the speed of modulation.
    An already mentioned above problem lies in the desire for as uniform as possible a load on the power supply, regardless of the respective current demand of the laser diode (s) corresponding to the modulation signal. In the prior art, therefore, a capacitor C is often used at the output of a high-capacity converter, resulting in a corresponding amount of space and cost.
    The invention now addresses this problem by the parallel connection of the analog controller 16, T2, which receives a diverted current Ib of the total current Ig, "analog", in contrast to known solutions with electronic switches in parallel, which by a PWM, the brightness of the laser diode In maximum current operation, no branched current Ib flows, so that no power dissipation occurs in the parallel branch, which would very well be the case if the linear stage or the analog regulator were connected in series with the laser diode branch Z.
    As soon as a modulation (dimming) of the laser diode (s) Dl in the sense of a reduction of the current through the laser diode (s) due to a desired light output in the light image or in the light image 11 'or due to a Ausblendszenarios is required, the modulation signal sm, the can be referred to as a reference signal for the operational amplifier 16, changed accordingly. At the input of the operational amplifier 16 on passing differential voltage leads to a driving of the transistor T2 in the sense of increasing the current Ib what further leads to a reduction of the current Id through the laser diode (s). Since the reduction of the diode current causes a reduction in the voltage Urs at the resistor Rs, which is supplied to the second input of the operational amplifier 16, the differential voltage at the input of the operational amplifier in the sense of the desired control goes to zero.
    FIG. 3 shows a further advantageous embodiment, which shows particular advantages if traffic-related skimming scenarios play a role. In such Ausblendszenarien an illuminance of less than 1 lx in the area to be hidden is required and preferably using a light scanner in the area to be hidden, the laser light source should be completely switched off or their emission is at least reduced so that there is no excitation of the light conversion means and thus the corresponding area in the photograph appears completely darkened.
    In this case, however, the problem arises that a complete "turn off" of the laser light source would mean their complete bridging, which would essentially equate to short circuiting, in order to avoid both such a load on the circuit and a fuse for a fault in the parallel circuit to ensure that can be arranged in this parallel circuit from the branched-off current Ib resistance RI in an advantageous manner, which in the case of a short-circuit or a complete "off" the laser light source 1, the output voltage of the boost converter 15 on a value defined by this resistor RI value holds.
    The value of the resistor RI is preferably selected so that in the case of a closed transistor T2, the current Id is reduced to that value at which the light output emitted by the laser light source 1 is no longer sufficient to excite the light conversion means 8 and, as a result, to a targeted suppression in the photo 11 'comes.
    In particular, the resistance of RI is chosen so that the laser supply voltage in the case of a closed transistor T2 falls below a threshold voltage typical for a laser diode, which ensures a fade. In the case of series connection of several laser diodes, this voltage is of course multiplied accordingly.
    The frequency response affecting, well-known to those skilled components that are used depending on the requirement are omitted in the schematic representations of Fig. I and 2.
    权利要求:
    Claims (8)
    [1]
    claims
    1. Lighting device for vehicles, which has at least one LED branch (Z) with at least one LED (LED1 .... LEDn), and with an LED driver (3) and a computing unit (4), which a drive signal (sm ) for the LED drive, and with a regulated power supply (15) for the LED drive, characterized in that the LED branch (Z) by a controlled parallel circuit (P) is bridged, which is used as a current regulator with an analog controller ( 16, T2) is formed and the drive signal (sm) is supplied to the analog controller.
    [2]
    2. Lighting device according to claim 1, characterized in that the illumination device is designed as a headlamp with at least one modulated laser diode (Dl) in the LED branch (Z) whose laser beam (2) by means of a light scanner (7) scanning a light conversion means (8 ) is steerable in order to generate a luminous image (11) thereon, which is projected onto the roadway (13) via an imaging system (12) as a light image (11 '), and to a laser diode driver (3) and a computing unit ( 4), which supplies as a drive signal, a modulation signal (sm) for the laser control.
    [3]
    3. Lighting device according to claim 1 or 2, characterized in that the analog controller (16, T2) has an operational amplifier (16) and a transistor (T2) controlled by this.
    [4]
    4. Lighting device according to one of claims 1 to 3, characterized in that the analog controller (16, T2) as a control variable to the current (Id) through the diode branch (Z) proportional signal is supplied.
    [5]
    5. Lighting device according to one of claims 1 to 4, characterized in that in the parallel circuit (P) of the branched-off current (Ib) through-flow resistor (RI) is arranged.
    [6]
    6. Lighting device according to one of claims 1 to 5, characterized in that the power supply is a DC-DC converter (15).
    [7]
    7. Lighting device according to claim 6, characterized in that the power supply is regulated to maximum load current.
    [8]
    8. Lighting device according to claim 7, characterized in that the power supply is a boost converter.
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    引用文献:
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    AT514834B1|2013-02-07|2017-11-15|Zkw Group Gmbh|Headlight for a motor vehicle and method for generating a light distribution|
    AT513916B1|2013-02-07|2015-04-15|Zizala Lichtsysteme Gmbh|Headlight for a motor vehicle and method for generating a light distribution|
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    AT516442B1|2014-11-07|2017-08-15|Zkw Group Gmbh|Headlamp for vehicles with at least one laser light source|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50444/2015A|AT517256B1|2015-06-01|2015-06-01|Lighting device for vehicles|ATA50444/2015A| AT517256B1|2015-06-01|2015-06-01|Lighting device for vehicles|
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    PCT/AT2016/050169| WO2016191783A1|2015-06-01|2016-05-31|Vehicle head light|
    CN201680031848.8A| CN107771413B|2015-06-01|2016-05-31|Vehicle headlight|
    US15/829,571| US10011214B2|2015-06-01|2017-12-01|Vehicle headlight|
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