DE102007002838A1 - Vehicle lamp, for interior and exterior illumination, has a number of LEDs fitted into a cooling body to take off heat - Google Patents

Abstract

The motor vehicle lamp, for internal and external illumination, has a number of LEDs (6) directly bonded to a cooling body (2) to take off the heat loss from them. A housing (4) is of a heat-conductive material for at least one LED, held in an opening or recess (3) in the cooling body in a force fit. Each LED is within its own cooling element (7), in contact with the housing.

Description

State of the art

The The present invention relates to an LED module suitable for installation in a lighting unit is determined, wherein the LED module has a plurality of LED components includes, which are mounted on a printed circuit board that they directly or indirectly with a to dissipate the heat loss of the LED components provided heatsink connected are.

such Illuminating units can both for the purposes of interior lighting and outdoor lighting be used. In particular, a use of such lighting units is also in or on motor vehicles possible. As light-emitting LED components (LED = light emitting diode) can optical semiconductor devices in the form of light-emitting diodes, in particular Light-emitting diode chips (LED chips) are used. Usually is doing a variety of LED devices (in the following also LEDs) arranged in an array, the LEDs preferably as surface-mounted SMD element (SMD = surface mounted device) by soldering or Gluing on a support or a printed circuit board.

Not only in motor vehicles LEDs are increasingly used as they across from conventional light bulbs have some significant advantages. So LEDs have a longer life, a smaller size as well better efficiency in the conversion of electrical energy in Light. Furthermore, LEDs are characterized by insensitivity to shocks and shocks from what a particular advantage, especially in motor vehicles represents.

In spite of the compared to incandescent lower heat output must also be against the background of a constantly increasing performance in the case of LEDs, the waste heat which occurs as a loss is dissipated to overheat and thus a functional impairment or even a destruction to prevent the LEDs. Usually is the waste heat from the underside of the LED components via their electrical connections and / or via a as a heat connection serving third contact to a metallic heat sink dissipated.

For example, to arrange a plurality of LEDs or a plurality of LED groups in a headlight of a motor vehicle, flexible printed circuit boards are usually equipped with LEDs in a two-dimensional plane, and then the flexible structure thus obtained is glued to a heat sink. The heat sink can, as it is from the DE 199 22 176 A1 is known, for example, made of copper or aluminum, which have desired for the particular application, three-dimensional shape and be provided on the side remote from the circuit board surfaces with cooling fins. The printed circuit board is preferably attached to the heat sink with a thermal paste, a thermal adhesive, a heat-conducting foil or the like, with an exact alignment of the LED components is difficult and just like the sticking of the circuit board to the heatsink means a considerable assembly effort.

Further It is known, ready-made LED lighting modules (short also LED modules called) in which a certain number of LEDs in a particular arrangement are combined to form a module, for the required amount of light for to achieve certain applications. Such modules can be relatively easy to mount in a lighting unit.

Also in the LED modules, the LEDs are soldered to a structured circuit board or glued, which by a rigid or flexible circuit board or may be formed by an IMS substrate. High-Brightness LEDs have besides the two electrical connection contacts yet a third contact, about the loss of heat the LED dissipated becomes. This heat connection, which is generally not floating, is limited to a surface area of the circuit board soldered or glued over the layout is designed so that it does not match the rest of the circuit is in electrical contact The heat is then over a electrical insulating layer in the circuit carrier to a metallic cooling carrier dissipated.

From the US 2005/0212439 A1 For example, an LED module with a plurality of LEDs is arranged, which are arranged on a flexible printed circuit board, which is attached to a heat sink. To improve the heat dissipation, the flexible circuit board is provided with holes through which the individual LEDs are in direct contact with the heat sink.

Disclosure of the invention

task The present invention is an improved LED module of to create the aforementioned type, with improved heat dissipation a simpler and more precise installation of the individual points of light LED module allows.

These The object is achieved by an LED module according to claim 1.

The idea underlying the present invention is that the LED module comprises at least one heat sink, which is connected to at least one LED component, and that the heat sink or at least one, preferably all heatsink, mounting means for a positive and / or non-positive mounting on another element of the LED module or the LED module receiving luminous unit.

On this way, a prefabricated and easy-to-install LED assembly created, not only a particularly good heat dissipation, but in particular also a quick and easy to perform mountability with improved Positioning accuracy of the individual LEDs allowed. So can the attached to the heat sinks, especially soldered LEDs during assembly of the LED module together with the form or force fit Successful mounting and alignment of the heat sink in a lighting unit be positioned.

The inventive LED module according to claim 1 thus has over the prior art embodiments especially the advantage of having an alignment of the individual LEDs when applying the circuit board on an arbitrarily shaped three-dimensional Element due to the connection made in advance in a two-dimensional plane the positive fit and / or non-positively mountable heat sinks omitted can, what the effort and therefore the cost of a with Such LED modules equipped lighting unit significantly reduced.

advantageous Further developments and improvements of the LED module according to the invention arise from the dependent ones Claims.

So For example, it is particularly advantageous if the LED module more Includes heat sink and the circuit board with openings is provided, wherein the LED components mounted on the circuit board are that they each connected through an opening with a heat sink are. In this way, the heat loss of the LEDs due to the direct Contact to a heat sink especially quickly and effectively dissipated be there the heat only over metallic and highly thermally conductive materials guided becomes. In a flexible circuit board, the individual heatsinks also movably arranged to each other and over the flexible Leiteplatte be connected to each other, which is the case for example with or bend lighting applications may be beneficial.

Farther It is particularly advantageous if each LED component with a own separate heatsink connected is. This allows Even more complex arrangements with a variety of LEDs especially Positionally placed on a three-dimensionally shaped carrier become. Also, there are particularly close tolerances of the individual LEDs can be achieved with each other. Furthermore, this is particularly simple Way an electrical insulation of the heat connections of the individual LEDs to each other guaranteed.

According to one First preferred embodiment of the invention provided that the mounting means of the heat sink in each case at least one Include recess, the form-fitting on each one projection an aggregate element can be placed. It is through the immediate form-fitting Positioning the heat sink too an indirectly form-fitting Positioning of the associated LEDs achieved. If several Heat sink provided the circuit board is advantageously designed to be flexible to ensure a certain relative mobility of the heat sink to each other. It is also possible the two form-fitting turn together interacting elements, so that on the heat sink a Projection is provided, the form-fitting in one on an aggregate element provided recess is used. In both cases will by the form fit a particularly exact, permanently reliable as well reproducible alignment of the heatsink and thus the advance LEDs connected to the previously fixed fixed points of the unit element reached. The protrusions may preferably massively formed on an element or embossed out of a contour. additionally can be a thermal adhesive between the projections and recesses are applied to a cohesive grip to achieve.

Especially It is advantageous if the recess is a self-centering Has shape. Thus, the recess may in particular a hemispherical, conical, frusto-conical or similar tapered Have inner contour. In this way, takes place during assembly of the LED module self-aligning the LEDs at the corresponding fix points of the aggregate element. When applying the assembled flexible printed circuit board on the aggregate element, the heat sink and thus also the so connected LEDs independently, at least within certain limits. Thereby can the disadvantages of a certain position inaccuracy in the placement of a large-scale flexboard or the disadvantage of possible elongations be corrected in their material as far as possible.

A particularly preferred embodiment provides that the heat sinks provided separately for each LED are each formed by a sleeve or sleeve closed on one side with a conical wall. This embodiment of the positive mounting not only a structurally particularly simple embodiment, but above all a particularly effective achieved heat dissipation. The heat dissipation takes place on the one hand on the inside of the sleeve directly to the form-fitting associated projection of the corresponding unit element as well as on the other hand by free convection on the outside of the soldered directly to the heat connection of the LED socket. The dissipated via the free convection in the interior of a lighting unit heat can be used in the case of a headlight advantageously also for heating or defrosting the protective glass of the headlamp. Preferably, the heat sink bush formed in this way is made of copper.

Especially Cheap Furthermore, it is when the individual heat sink with their recesses thermally conductive on complementary projections one as an LED carrier serving overall heat sink of the LED module or the Leuchtaggregats, preferably made of aluminum can exist. As a result, the heat dissipation via the individual heatsinks connected to the LEDs by direct contact preferably metallic, good heat-conducting Materials to a total heat sink, the for many or preferably for all LEDs of the LED module according to the invention or of the LED module receiving light unit is provided. The total heat sink can preferably formed in a conventional manner as Heatsink his and several cooling fins exhibit.

According to one second preferred embodiment The invention proposes that the mounting means of the heat sink, respectively comprise at least one elastically resilient holding region over which the heat sink frictionally or latching on an element of the LED module or the lighting unit can be attached. In this way, the heat sink in addition to their function for lead away the heat loss at the same time as a retaining clip for fixing the LED module or individual parts of it.

Especially It is advantageous if the heatsink each with a clip two opposite ones elastically resilient holding areas are formed, each Holding area for positive locking Engaging at least one projection and / or a recess or opening, over which the heat sink on another form-fitting element and / or non-positively is latched. This makes a particularly easy and fast executable Mounting the LED module to other elements allows.

Cheap for a desired light output can it continues to be, if optical means, in particular a plastic optics are provided in the LED module. These can in a particularly simple way on the elastically resilient holding areas detent connected to the heat sinks become.

If the printed circuit board through a flexible flat cable (FFC = flexible Flat cable) is formed, can advantageously be a flexible LED chain with several juxtaposed LEDs, each attached to a heat sink designed according to the invention which are particularly easy and quick to clip on the individual heat sink in one Illuminating unit, in particular in a spotlight housing, mountable is.

The The present invention further relates to a lighting unit with a plurality LED components and several heat sinks over the the heat loss the LEDs dissipated can be, wherein the lighting unit at least one, preferably but includes a plurality of LED modules of the type described above, the above at least one flexible printed circuit board and / or by at least a flexible flat cable are connected together. Such a thing Illuminating unit is due to the prefabricated and easy to install Overall, LED modules are particularly quick and easy to install, which is a low cost Manufacturing possible.

Especially It is advantageous if the lighting unit at least one serving as an LED carrier Has total heat sink, over the heat loss all LEDs dissipated can be, with the total heat sink more each as a fixed point for each one LED serving projections has, on each of which a heat sink of an LED component is seated. As a result, a particularly effective dissipation of the heat loss of the LEDs reached. in principle but are the heatsinks too on protrusions other elements of the lighting unit mountable.

Especially It is also advantageous if the lighting unit according to the invention a headlight, in particular a motor vehicle headlight, the comprises a headlamp heat sink, positively received or clipped on the at least one LED module is. The present invention can thus be used in particular in the automotive sector, but also in general lighting applications in an advantageous manner be used.

The present invention furthermore relates to a method for mounting an LED module according to the above-described first particularly preferred embodiment of the invention, in which module the mounting means of the heat sink each comprise at least one recess which is positively connected to a respective projection of an aggregate element or the LED. Module can be placed. This assembly method according to the invention is characterized in that at least a few projections of the aggregate element or the LED module via a opening into the projections line system, a negative pressure is applied. For this purpose, openings are provided in the projections, to which the preferably formed by bores, channels, and / or hoses line system connects, which is connected to a pump for generating a negative pressure. As a result, the heatsink are sucked when the negative pressure on the projections and tightened there, which further simplifies the assembly considerably further. In particular, when a thermally conductive adhesive is applied between the projections and the recesses, the suction force required for a cohesive hold of the heat sink can be applied by the suction of the heat sink to the unit element or to the LED module.

Brief description of the drawings

In The drawings are exemplary embodiments of the invention shown in the following description be explained in more detail. Show it:

1 : Three-dimensional, partially sectioned illustration of an LED module according to the invention;

2 : Three-dimensional representation of a heat sink, on which the LED module off 1 can be mounted;

3 : Three-dimensional, partially cut representation of the heat sink 2 with LED module mounted on it 1 ;

4 : Three-dimensional representation of an arrangement with a plurality of LED modules according to the invention;

5 : Three-dimensional representation of a second embodiment of an LED module according to the invention;

6 : Module flexible circuit board of 5 ;

7 : Illustration of a single heat sink of the module 5 ;

8th Three-dimensional representation of a third embodiment of an LED module according to the invention;

9 : Partial sectional view of a LED module behind 8th with attached plastic optics; and

10 : Representation of an arrangement with several modules linked together 9 ,

Embodiments of the invention

That in the 1 to 4 shown LED module 1 is intended for installation in a lighting unit, not shown in the figures. It comprises a flexible circuit board serving as a circuit carrier 2 on which a variety of LED components 3 is arranged, which are each designed here as a surface-mounted LED chips. Every single LED chip 3 is doing it with its own heat sink 4 connected here in the form of a bottom closed socket with a conical wall 5 is executed. The circuit board 2 has on every LED component 3 an opening through which one for dissipating the heat loss of the LED 3 provided central third contact with the ground 6 the associated heat sink 4 is firmly connected by soldering. The two electrical connections 7 the LED components 3 are on the heatsinks 4 opposite top of the circuit board 2 connected to the printed conductors ( 1 ).

The individual heatsink sockets 4 have between their conical inner walls 5 a recess 8th that to that of the circuit board 2 opposite end is open. About these recesses 8th are the heatsinks 4 each form-fitting on a respective frustoconical projection formed 9 attachable, the one piece to a serving as an LED carrier heat sink 10 of the lighting unit is formed ( 2 ). The projections 9 fill as complementary counterparts the cavity or the recess 8th the heat sink 4 completely made, so that an optimal heat transfer is ensured only by metallic, good heat conducting materials. The heat sink bushes made of copper 4 serve as heatspreader, while the existing here of aluminum total heat sink 10 with several molded cooling fins 11 as heatsink serves ( 3 ).

The outsides of the copper sleeves 4 are heated via free convection directly into the interior of the lighting unit. In addition, a dissipation of the heat loss takes place via the inside of the copper sleeve 4 to the overall heat sink 10 from where the heat is dissipated to the environment of the lighting unit. This can be the inside of the heat sink socket 4 in addition, via a thermal adhesive with the associated positive projection 9 of the entire heat sink 10 get connected.

Due to the conical shape of the projections 9 and the complementary recesses 8th the associated heat sink 4 results from the assembly of the LED module according to the invention 1 automatically self-adjusting the heat sink 4 and thus also the LED components attached thereto 3 , When applying the assembled flexible printed circuit board 2 on the overall heat sink 10 the heat sink bushes are aligned 4 with the LED components soldered to it 3 to the through the projections 9 formed fixed points independently, so that with ease of mounting improved positional accuracy can be achieved.

At the in 4 arrangement shown are multiple LED groups for different light functions on a common flexible circuit board 2 arranged. The entire circuit board 2 is initially in a two-dimensional plane with the surface mountable LED components 3 equipped and then on several three-dimensionally shaped LED support plates or overall heat sink 10 applied. The exact location of each LED 3 is doing by the through the projections 9 formed fixed points of the entire heat sink 10 determines, resulting in a particularly favorable tolerance chain. Furthermore, at the in 4 arrangement shown in an advantageous manner no connections between the individual LED modules 1 required. The to control the individual LED modules 1 required control electronics and possibly other electronic circuits can also on the circuit board 2 arranged and in which with the LED modules 1 equipped lighting unit can be accommodated.

At the in 5 illustrated embodiment, four LED components 3b on each a separate clip-shaped heat sink 4b soldered. These are in the here formed by a flexible flat cable circuit board 2 B first openings 12 punched ( 6 ), through which the LED components 3b the floors 6b at a central extent 13 to contact ( 7 ). The individual heatsinks 4b be before connecting with the LEDs 3b on the circuit board 2 B glued.

At two opposite edges of the ground 6b is in each case an elastically resilient, outwardly bendable holding area 14 with an opening made in it 15 formed. About these two elastically outwardly bendable holding areas 14 can the heat sink 4b positive and / or non-positive on other elements of the LED module 1b or one the LED module 1b be mounted on the receiving luminous unit. Basically, depending on the purpose any number of LED chips 3b in any arrangement in the LED module 1b be provided.

In the in the 8th to 10 illustrated embodiment of an LED module 1c is each a heat sink 4c for every six LED components connected in series 3c intended. Otherwise, the construction corresponds to the heat sink 4c but essentially the design of the heat sink 4b from the 5 to 7 , At the side elastically bendable holding areas 14c There are two openings here 15 educated about the in the in the 9 and 10 illustrated embodiment each have a plastic look 16 for the respective LED module 1c is latched attached. The plastic look 16 has to laterally projecting projections 17 with an inlet slope 18 in the mounted state in the openings 15 the holding areas 14 intervention.

On the in 10 way shown, several LED modules according to the invention 1c through an FFC matrix of flexible ribbon cables 2c be connected to each other. A thus obtained flexible network with linked LED modules 1c is relatively easy to mount in a lighting unit, for example, in a car headlight. In this case, then the LED modules 1c each individually adjusted, whereas the individual LED components 3c within the LED modules 1c already adjusted in advance. In this way, the flexible networks of LED modules 1c particularly easy to be adapted to the different headlights of different vehicle types. In addition, generously dimensioned heat paths also provide for the ribbon cables 2c the ability to dissipate the dissipated heat loss to corresponding total heatsinks or in cheaper areas.

Claims (14)

LED module for installation in a lighting unit, comprising a plurality of LED components ( 3 . 3b . 3c ) mounted on a printed circuit board ( 2 . 2 B . 2c ) are mounted such that they are directly or indirectly connected to a heat sink ( 4 . 4b . 4c ), characterized in that the LED module ( 1 . 1b . 1c ) at least one heat sink ( 4 . 4b . 4c ), which is provided with at least one LED component ( 3 . 3b . 3c ), and that the heat sink ( 4 . 4b . 4c ) or at least one of a plurality of heat sinks ( 4 . 4b . 4c ) Mounting means ( 8th . 14 . 15 ) for a positive and / or non-positive mounting on another element ( 10 . 16 ) of the LED module ( 1 . 1b . 1c ) or of the lighting unit. LED module according to claim 1, characterized in that the LED module ( 1 . 1b . 1c ) several heat sinks ( 4 . 4b . 4c ), wherein the LED components ( 3 . 3b . 3c ) on one with openings ( 12 ) provided printed circuit board ( 2 . 2 B . 2c ) are mounted so that they each through an opening ( 12 ) through with a heat sink ( 4 . 4b . 4c ) are connected. LED module according to claim 1 or 2, characterized in that each LED component ( 3 . 3b . 3c ) with its own heat sink ( 4 . 4b . 4c ) connected is. LED module according to one of claims 1 to 3, characterized in that the mounting means of the heat sink ( 4 ) at least one recess ( 8th ), which form-fit on each one projection ( 9 ) of an aggregate element ( 10 ) can be placed. LED module according to claim 4, characterized in that the recess ( 8th ) has a self-centering shape, in particular a hemispherical, conical or frusto-conical tapered inner contour. LED module according to claim 5 in conjunction with claim 3, characterized in that the heat sinks ( 4 ) each by a one-sided by a floor ( 6 ) closed socket with a conical wall ( 5 ) are formed. LED module according to one of claims 4 to 6, characterized in that the heat sink ( 4 ) with their recesses ( 8th ) thermally conductive on complementary projections ( 9 ) of a total heat sink ( 10 ) of the LED module ( 1 ) or the lighting unit are included. LED module according to one of claims 1 to 3, characterized in that the mounting means of the heat sink ( 4b . 4c ) at least one elastically resilient holding area ( 14 ), by means of which the heat sink ( 4b . 4c ) frictionally or latchingly on an element ( 16 ) of the LED module ( 1b . 1c ) or the lighting unit can be fastened. LED module according to claim 8, characterized in that the heat sink ( 4b . 4c ) in each case in the shape of a clip with two elastically resilient holding regions ( 14 ) are formed, each holding area ( 14 ) for positive locking at least one projection and / or a recess or opening ( 15 ). LED module according to claim 8 or 9, characterized in that the heat sink ( 4b . 4c ) latching with optical means of the LED module ( 1b . 1c ), in particular with a plastic look ( 16 ), are connected. Illuminating unit with several LED components ( 6 ), characterized in that it comprises at least one LED module ( 1 . 1b . 1c ) according to one of the preceding claims, wherein preferably several LED modules ( 1 . 1b . 1c ) via a common flexible printed circuit board ( 2 . 2 B . 2c ) are interconnected. Illuminating unit according to claim 11, characterized in that it has at least one LED carrier serving as a total cooling body ( 10 ) comprising a plurality of projections ( 9 ), on each of which a heat sink ( 4 ) of an LED component ( 3 ) is recorded. Illuminating unit according to claim 11 or 12, characterized in that it is designed as a headlight, in particular as a motor vehicle headlight is. Method for mounting an LED module according to one of claims 4 to 7, characterized in that at least a few projections ( 9 ) of the aggregate element ( 10 ) or the LED module ( 1 . 1b . 1c ) is applied via a opening into the projections line system, a negative pressure.