• 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 motor vehicles with at least one laser light source (1), the laser beam (3) is directed to at least one light conversion means having a phosphor (6) for light conversion, and with a projection system (8) for the projection of the generated at the at least one light conversion means Light (7) in the carriageway space, wherein at least two electrodes (10, 11) are arranged on the phosphor (6), which form the coverings of a capacitor (CP) with the phosphor (6) as a dielectric, and a measuring device (12 ) is provided, with which the at least two electrodes (10, 11) are connected and which is adapted for measuring the capacitance of the capacitor (CP) and for outputting a signal (s), if the determined capacitance outside a predetermined tolerance range by a set value lies.
    公开号:AT518287A1
    申请号:T50134/2016
    申请日:2016-02-25
    公开日:2017-09-15
    发明作者:Griessler Christian
    申请人:Zkw Group Gmbh；
    IPC主号:
    专利说明:

    Headlight for motor vehicles with at least one laser light source
    The invention relates to a headlight for motor vehicles with at least one laser light source whose laser beam is directed to at least one light conversion means having a phosphor for light conversion, and with a projection system for projecting the light generated at the at least one light conversion means in the Pahrbahnraum.
    Laser light sources (e.g., semiconductor lasers, laser diodes) have a number of special advantageous properties, such as e.g. high radiation intensities and a small light-emitting surface on. In addition, the emitted light beams are largely collimated.
    This results in a number of advantages for the use of laser light sources for illumination purposes, especially for cars. For example, optical systems in which a laser light source is used as the light source can be realized with smaller focal lengths and more focused beam progressions. This is not possible with less strongly collimated light bundles - for example from incandescent lamps or LEDs. It can thus be realized with the use of laser light sources optical systems for laser light with little space.
    Lasers typically emit monochromatic light or light in a narrow wavelength range. However, in a vehicle headlamp, "white" mixed light is desired or prescribed by law for the radiated light, so that laser light sources in a vehicle headlamp are not readily usable and light conversion means are used in Porm of a slide, which will be described in more detail below.
    When using laser light sources results in the problem that they represent a high risk potential, in particular for the human eye. This is because lasers typically emit coherent and highly collimated light, which is potentially dangerous at the typical high radiation intensities of laser light sources. This is especially true at radiation powers of a few watts, as is desirable in the field of automotive lighting.
    Therefore, in order to be able to use laser light sources in the motor vehicle sector, in particular for motor vehicle headlamps, safety regulations for the operation of laser devices must be observed. In particular, it must be ensured that light (laser light) escapes from a motor vehicle headlight only at an intensity below prescribed limits. In addition, dazzling or endangering road users must be avoided.
    There is a particular risk in damage to the phosphor, such as a break or the occurrence of cracks or perforations. In such a case, at least a portion of the primary laser beam penetrates the phosphor, passes through the headlamp projection system on the road and can endanger people.
    It is an object of the invention to provide a headlamp, in which a malfunction in the sense of partial or complete damage of the phosphor can be detected with little effort, so that measures can be taken to prevent the danger emanating from the laser interference radiation endangerment or minimal hold.
    This object is achieved on the basis of a headlamp of the type described, according to the invention in that at least two electrodes are arranged on the phosphor, which form the linings of a capacitor with the phosphor as a dielectric, and a measuring device is provided, with which the at least two Electrodes are connected and which is adapted to measure the capacitance of the capacitor and to output a signal if the determined capacity is outside a specified tolerance range around a desired value.
    An expedient and advantageously realizable development of the invention is characterized in that the measuring device is designed as an alternating voltage measuring bridge and the capacitor is connected to the phosphor as a dielectric in a bridge branch.
    It may be particularly advantageous if the AC voltage bridge is a Vienna bridge.
    Furthermore, it is expedient if in a further bridge branch, a reference capacitor, which is the same as the phosphor configured.
    It can also be provided with advantage that the phosphor is cuboidal.
    On the other hand, it is in many cases opportune if the phosphor is platelet-shaped.
    In expedient embodiments of the invention, it is provided that the phosphor is transmissive.
    It is very advantageous in many cases when the electrodes are transparent.
    In this case, the electrodes can advantageously consist of vapor-deposited indium tin oxide.
    Also, it may be appropriate for certain headlamp variants, if the phosphor is reflective.
    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
    Fig. 1 in a schematic representation of an embodiment of a headlamp with the essential components of the invention
    2 shows a detail of FIG. 1 in an enlarged view,
    3 is a further enlarged perspective view of a phosphor with electrodes,
    Fig. 4 in side view a phosphor with damage and
    Fig. 5 shows a possible measuring bridge for determining a change in capacitance
    With reference to Fig. 1, an embodiment of the invention will now be explained in more detail. In particular, the important parts for a headlight 1 according to the invention are shown, it being understood that a motor vehicle headlamp contains many other parts that allow its meaningful use in a motor vehicle, such as in particular a car or motorcycle. It should be noted at this point that the "headlight" shown and described here can also serve as a headlight module or as a lighting unit that is seated in a headlight that has a plurality of modules.
    Lighting technical starting point of the headlamp is a laser light source 2, which, bundled by a focusing optics 3 emits a laser beam 4. The laser light source is associated with a laser driver 5, which is used for power supply as well as for monitoring the laser emission or e.g. serves for temperature control and can also be configured 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.
    The laser light source 2 emits, for example, blue or UV light in the form of the laser beam 4, which impinges on a phosphor 6 of a light conversion agent, which serves to convert light in a known manner. The phosphor 6 - one could also speak of a phosphorus body - converts blue or UV light, for example, into "white" light. By "phosphorus" in the context of the present invention is generally understood a part of a substance or mixture of substances which transmits light of one wavelength to another
    Wavelength or a wavelength mixture, especially in "white" light, converts, which is subsumed under the term "wavelength conversion".
    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. For the light conversion agent - the "phosphor" - are for example optoceramics in question, these are transparent ceramics, such as YAG: Ce (an yttrium-aluminum garnet doped with cerium).
    The phosphor usually has the shape of a small plate, whereby it is possible to work according to the reflected-light or the transmitted-light principle. In the first case ("reflective", reflected light), the converted light is radiated on the same side as the laser beam is incident, in the second case shown in Fig. 1 ("transmissive", transmitted light), the converted light is emitted on that side. which is opposite to the side irradiated by the laser. In both cases, the light used can also be made from a mixture of e.g. blue laser light with the converted light to obtain as "white" as possible light.
    The phosphor 6 is cuboid in the present case, but it may also, depending on the specific application, be platelet-shaped, i. a body in which one dimension is very small compared to the others. The phosphorus does not have to be even, it can also have a curvature.
    As mentioned above, in the present case the phosphorus 6 is transmissive, i. the light emitted on the opposite side of the laser beam incidence is a mixed light 7 of the desired color emitted over a large solid angle. This mixed light 7 emanating from the phosphor is projected into the carriageway space by means of a projection system 8, which is designed here as a reflector.
    If the phosphor 6 has damage, such as overheating or breakage, the laser beam 4 may pass through the phosphor 6. In Fig. 1 is a passing through an incident, compared to the mixed light strongly focused and correspond to energy-dense interference beam 9 is located. It is clear that such a relatively high-energy interfering beam could pose a potential danger to living beings, in particular to human eyesight, since it would leave the headlight 1 through the projection system 8 and cause damage.
    In order to immediately detect such an accident, the invention now provides that at least two electrodes are arranged on the phosphor 6, in FIG. 1 the electrodes 10, 11, which form the linings of a capacitor Cp with the phosphor as a dielectric, and a measuring device 12 is provided, with which the electrodes are connected and which is adapted to measure the capacitance of the capacitor Cp and to output a signal s, if the determined capacitance lies outside a specified tolerance range around a desired value. In Fig. 1, two lines 13, 14 are shown, which connect the electrodes 10, 11 with the measuring device 12. The signal s may be supplied to the laser driver 5 to cause it to switch off the laser light source 2 immediately if there is an accident and also the signal s may be applied to a display device 15 for delivery e.g. be fed to an alarm signal.
    In Fig. 2, which shows an enlarged detail of Fig. 1, it is also recognized that the phosphor can optionally be encapsulated, e.g. by means of transparent or translucent cover plates 16,17, so that disturbing environmental influences, such as a condensate on the phosphor can not occur or the capacity or the impedance of the phosphor 6 is not affected thereby. On the other hand, it is also possible to provide no encapsulation and intentionally by a corresponding design of the electrodes, the capacity to make highly dependent on surface deposits. Thus, for example, a condensation on the surface of the phosphor can be detected, which is dangerous for the operation, as by a deflection, a deflection of the laser beam occurs and thus the risk of an unscheduled leakage of a laser interference 9th
    FIG. 3 shows, in a further enlarged representation, a parallelepipedic phosphor 6 with two electrodes 10, 11, from which lines 13, 14 emanate, the phosphor body having a dielectric constant ε at an electrode spacing d. Of course, the electrodes could also be arranged on other, but preferably not necessarily opposite surfaces of the phosphor.
    FIG. 4 shows a side view of a damaged phosphor 6 showing damage in the form of cracks 18. Such cracks result in a change in the capacitance of the capacitor Cp formed by the electrodes 10, 11 and the phosphor 6.
    As for the measuring device 12, it should be clear to those skilled in the art that there are innumerable measuring methods and devices for capacity measurement. In particular, alternating current measuring bridges are suitable, of which the Wien bridge known to the measuring technician is shown in FIG. The bridge contains four pointing, two branches having resistors R2 and R3, and the other two branches having impedances consisting of a capacitor and a shunt resistor in the equivalent circuit shown. In an impedance branch is to be measured, here variable capacitor Cp of the phosphor 6 and the parallel resistor Rp, which is also represented by the phosphor. In the other impedance branch is a reference capacitor Ci and its associated resistor Ri. The bridge is located with two bridge nodes at an AC voltage Uw. If the bridge is in a balanced state, the voltage Uo between the other two bridge nodes is zero. Applied to the invention, it makes sense to make the reference capacitor Ci the same in electrical terms as the capacitor Cp formed by the phosphor 6.
    In undisturbed operation of the headlamp, namely undamaged phosphorus, the bridge is balanced. If, for example, a crack 18 (FIG. 4) occurs in the phosphor 6, the capacitance of the capacitor Cp changes, the bridge is detuned and a voltage Uo occurs which can be detected in the measuring device 12 and utilized accordingly.
    It should again be emphasized that this method of detecting a change in capacity is only one of many possibilities which are available to the person skilled in the art. In principle, furthermore, with a corresponding design of the measuring device, a change of the parallel resistor Rp could additionally or alternatively be evaluated as a criterion for a fault condition of the phosphor.
    Furthermore, it is often useful if the electrodes are transparent and consist for example of vapor-deposited indium tin oxide. Of course, such a solution can be advantageously applied to a transmissive phosphor.
    In principle, it is possible to use both reflective and transmissive beam paths for the headlight, with a mixture of reflective and transmissive beam paths ultimately not being ruled out.
    The headlight may also be one with a scanning laser system in which an image is "written" on the phosphor by a laser beam deflected by micromirrors, which image is then projected onto the road via an imaging system Headlamps for generating an image by a scanning laser beam is described approximately in the published Austrian patent application AT 514 633 A1 of the applicant.
    List of Reference Numbers 1 Headlamp 17 Cover Plate 2 Laser Light Source 18 Cracks 3 Focusing Optics 4 Laser Beam s Dielectric Constant 5 Laser Drive Cp Capacitor 6 Phosphor Ci Capacitor 7 Mixed Light Ri Resistor 8 Projection System R2 Resistor 9 R3 Strain Resistance 10 Electrode Rp Resistor 11 Electrode 12 Measurement Device 13 Wire Uw AC Voltage 14 Cable Uo Voltage 15 Display d Distance 16 cover plates
    权利要求:
    Claims (10)
    [1]
    claims
    1. A headlamp for motor vehicles with at least one laser light source (1), the laser beam (3) is directed to at least one light conversion means having a phosphor (6) for light conversion, and with a projection system (8) for the projection of the at least one light conversion means generated light (7) in the carriageway space, characterized in that at least two electrodes (10, 11) are arranged on the phosphor, which form the coverings of a capacitor (Cp) with the phosphor as a dielectric, and a measuring device (12) is provided to which the at least two electrodes are connected and which is arranged to measure the capacitance of the capacitor and to output a signal (s) if the determined capacitance lies outside a defined tolerance range around a desired value.
    [2]
    2. Headlight according to claim 1, characterized in that the measuring device is designed as an alternating voltage measuring bridge and the capacitor is connected to the phosphor as a dielectric in a bridge branch.
    [3]
    3. Headlight according to claim 2, characterized in that the AC voltage bridge is a Vienna bridge.
    [4]
    4. Headlight according to claim 2 or 3, characterized in that in a further bridge branch, a reference capacitor is the same as the phosphor is configured.
    [5]
    5. Headlight according to one of claims 1 to 4, characterized in that the phosphor is cuboidal.
    [6]
    6. Headlight according to one of claims 1 to 4, characterized in that the phosphor is formed platelet-shaped.
    [7]
    7. Headlight according to one of claims 1 to 6, characterized in that the phosphorus is transmissive.
    [8]
    8. Headlight according to one of claims 1 to 7, characterized in that the electrodes are transparent.
    [9]
    9. Headlight according to claim 8, characterized in that the electrodes consist of vapor-deposited indium tin oxide.
    [10]
    10. Headlight according to one of claims 1 to 9, characterized in that the phosphor is reflective.
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    同族专利:
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    CN206592964U|2017-10-27|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102012220481A1|2012-11-09|2014-05-15|Automotive Lighting Reutlingen Gmbh|light module|
    WO2016156000A2|2015-04-01|2016-10-06|Osram Gmbh|Device and method for light conversion device monitoring|
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    DE102017204867A1|2017-03-23|2018-09-27|Osram Gmbh|Converter device with a phosphor element|
    DE102017212964A1|2017-07-27|2019-01-31|Osram Gmbh|LIGHTING DEVICE AND HEADLIGHTS|
    CN109808582A|2018-04-24|2019-05-28|长城汽车股份有限公司|Projecting method, device based on headlamp|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA50134/2016A|AT518287B1|2016-02-25|2016-02-25|Headlight for motor vehicles with at least one laser light source|ATA50134/2016A| AT518287B1|2016-02-25|2016-02-25|Headlight for motor vehicles with at least one laser light source|
    DE202017100639.5U| DE202017100639U1|2016-02-25|2017-02-07|Headlight for motor vehicles with at least one laser light source|
    CN201720170852.4U| CN206592964U|2016-02-25|2017-02-24|The headlight with least one LASER Light Source for motor vehicle|
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