This application claims priority to PCT Application No. PCT/EP2019/051598, filed Jan. 23, 2019, the entirety of which is hereby incorporated by reference.
The present invention relates to an Illumination device for a vehicle, comprising an optical device, in particular a reflector, with a dome and with a positioning pin and further comprising a light emitting assembly with a printed circuit board and a semiconductor light source, in particular a light emitting diode.
Semiconductor light sources such as light-emitting diodes and lasers are increasingly used in illumination devices for vehicles, in particular headlamps, signal lights, taillights and brake lights of cars. Semiconductor light sources have the advantage over traditional light bulbs, that they are more reliable, have a longer lifetime and that they consume less electrical power at the same light flux intensity. Traditional light bulbs radiate light in omnidirectional manner. Semiconductor light sources radiate light in a more directional manner and therefore the amount of light and electrical power needed is less. Nevertheless, in particular due to the more directional radiation of light from semiconductor light sources, an exact position relative to optical devices such as a reflector or a lens is critical and crucial. A placement of the semiconductor light source outside a designated position relative to the optical devices can lead to significant deviations in shape, direction and intensity of a light cone.
The US 2007/0268703 A1 discloses a vehicle lighting comprising a reflector, a heat dissipation base and a printed circuit board with a light-emitting diode. According to the teaching of the patent a positioning of the reflector relative to the printed circuit board with the light-emitting diode and relative to the heat dissipating base is achieved by pins and studs fitting in or protruding through holes in the printed circuit board and the heat dissipation base. According to the teaching the method for manufacturing the orienting studs allows precise dimensions and tolerances to be obtained.
The AT 51 44 03 B1 discloses an illumination device for a vehicle and a vehicle headlight. To avoid a deformation and a resulting deviation in the light cone when tightening a LED-light source to an optical device a temporary positioning means is proposed. A LED-light source carrier with the LED-light sources is positioned on the optical device. According to the teaching of the patent document a pin and a dome on the optical device is received by cut-outs of the LED-light source carrier. Holding springs on the optical device press the LED-light source carrier against the dome. The LED-light source carrier is thus positioned and temporarily fixed to the optical device by the dome and the pin. A fixed arrangement of the illumination device without screws is proposed. To realize that fixed arrangement, a cooling device is positioned on the LED-light source carrier and a fixation element with clamps is slid onto the cooling device, wherein receiving elements on the dome receive the clamps. By sliding the clamps of the fixation element under the receiving element of the dome a clamping force is generated. The cooling device, the LED-light source carrier and the optical device are pressed and held together by that clamping force.
Components of an illumination device such as the optical device, the dome, the pin, the light emitting assembly, the LED-light source carrier feature at least slight variations in dimensions from manufacturing. Consequently, it is inevitable to manufacture the components with slight tolerances to ensure that the components can be assembled together into the illumination device. A disadvantage of the tolerances is, that they lead to variations in position of the optical device, in particular the LED-light source, relative to the light emitting assembly and resulting in variations and possibly even a defective light cone.
A further disadvantage of an illumination device with many parts is, that the assembly is time consuming and complex.
It is an object of the present invention to provide a simple and reliable means to precisely position the light emitting assembly relative to the optical device in a predetermined position.
The core of the invention lies in that the light emitting assembly comprises a bracket with at least one spring for exerting a pretension force on the dome of the optical device, and the printed circuit board comprises a positioning hole for receiving the positioning pin and to position the light emitting assembly relative to the optical device.
In a preferable embodiment, the printed circuit board is attached to a baseplate, on a side facing the optical device and cooling fins are attached, in particular riveted, to the baseplate on an opposite side of the base plate facing away from the optical device. The semiconductor light source is expediently located on the printed circuit board facing the optical device. Thus, a particularly compact design of the light emitting assembly with integrated and reliable cooling is achieved. An additional advantage lies in that an assembling of the illumination device is eased.
Advantageously, the bracket is positioned on an opposite side of the light emitting assembly facing away from the optical device and the dome protrudes through an opening in the light emitting assembly in particular an opening in the baseplate and/or an opening in the printed circuit board. This arrangement simplifies the placement of the illumination device onto the optical device. In particular visual inspection is possible during lowering the bracket onto the dome. Expediently the dome is only in contact with the bracket, in particular with the first and/or second positioning spring. The opening is sufficiently large, so that the dome is free of a contact with the printed circuit board or the baseplate.
To achieve a particularly precise and failsafe positioning, the positioning hole comprises a wall forming an end stop to a contact section of the positioning pin. The positioning hole is preferably sufficiently larger and shaped such that the positioning pin fits into the positioning hole without obstruction. The positioning pin may feature a shape to which facilitates an insertion into the positioning hole. As the position is defined by the contact section of the pin and the wall of the positioning hole in the printed circuit board, tolerances and variations of other components are insignificant. In other words, only the wall of the positioning hole forming an end stop for the positioning pin is deterministic for the position of the illumination device relative to the optical device. Wherein the pretension force from the spring causes the positioning.
According to another preferred embodiment with particularly inexpensive, reliable and easy positioning, the bracket is made of a sheet metal, in particular a single piece of sheet metal. In addition, or alternatively the bracket comprises a first spring and a second spring and at least a portion of a pretension force of the first spring acts into a direction perpendicular to a pretension force of the second spring. This allows to easily and automatically position the light emitting assembly relative to the optical device in a two-dimensional plane. Due to the perpendicular pretension force from the first spring and the second spring the light emitting assembly is pushed into on particular direction relative to the optical device and the positioning pin is held in a particular position in the positioning hole.
To avoid tension forces and a deformation of the optical device and printed circuit board, the dome comprises a screw hole and the bracket comprises a bracket hole, and the screw hole and the bracket hole are aligned to one another for receiving a screw and mounting the bracket with the light emitting assembly to the optical device with that screw. In a fixed position the bracket is clamped between the screw and the dome. Thus, a force from the screw for fixing the bracket with the light emitting assembly to the optical device is decoupled from the printed circuit board. This enables a reliable and releasable connection between the optical device and the light emitting assembly for access to or replacement of the components. The bracket hole preferably has a larger diameter than the screw hole to enable an insertion of the screw after positioning of the light emitting assembly relative to the optical device. The fixation with the screw also avoids a movement of the optical device in a z-direction away from the optical device.
To avoid a rotational movement or a rotational misalignment of the light emitting unit relative to the optical device, the printed circuit board comprises a fixation hole for receiving a fixation pin of the optical device. The fixation hole can be of an oval shape such that the cylindrical fixation pin just fits into the widest portion of the fixation hole. Preferably the fixation pin and the positioning pin are spaced apart from one another by at least 20 mm and preferably at the greatest possible distance. The fixation hole and the positioning hole are preferably located on opposite far ends of the printed circuit board.
To keep tolerances small and the positioning of the printed circuit board with the semiconductor light source particularly precise, the positioning pin and/or the fixation pin are made from one piece with the optical device. Thus, variations in position from the mounting of the fixation pin or the positioning pin to the optical device is excluded.
The aforementioned components, as well as the claimed components and the components to be used in accordance with the invention in the described embodiments, are not subject to any special exceptions with respect to their size, shape, material selection and technical concept such that the selection criteria known in the pertinent field can be applied without limitations.
Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.
Referring to the above described illumination device and cited figures, a particular advantage comes into effect by lowering the light emitting assembly 200 onto the reflector 300 in a direction parallel to the z-axis 70. Wherein the pads 340 form an end stop to the printed circuit board 210 in the z-direction 71. When lowering the illumination device 200 onto the reflector 300 the fixation pin 320 is received in the fixation hole 215, the positioning pin 330 is received in the positioning hole 210 and the dome 310 is received in the bracket 220, wherein the first spring 224 and the second spring 225 exert the force on the dome 310 to position the illumination device 200 relative to the reflector 300 in the x-y plane. In particular the combination of the force from the first spring 224 in the x-direction 51 and the force from the second spring 225 in the y-direction 61 results in a directionality in the x-y plane causing the contact section 331 to contact the wall 214 of the positioning hole 210 forming the end stop in a single particular point in the x-y plane. Consequently, a precise positioning in three dimensions is achieved automatically and failsafe with only one single manual movement in the z-direction 71.
The present invention is not limited by the embodiment described above, which is represented as an example only and can be modified in various ways within the scope of protection defined by the appending patent claims. Thus, the invention is also applicable to different embodiments, in particular of the design of other optical devices such as a lens.
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514403 | Jun 2015 | AT |
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Number | Date | Country | |
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20210372585 A1 | Dec 2021 | US |
Number | Date | Country | |
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Parent | PCT/EP2019/051598 | Jan 2019 | US |
Child | 17371474 | US |