DE102013009146B4 - Light module with LED - Google Patents

Abstract

Light module (12) with at least one LED (23) which is electrically insulating but heat-conducting mounted on a heat sink (11) which is at least partially surrounded by a pin (16) equipped with plastic enclosure (13), characterized in that in the course of electrical connections between the pins (16) and the LED (23) pasty cable runs (20) are provided which extend over the outer surface (22) of a metal heat sink (11) on tracks (30) of electrical insulating paste.

Description

The invention relates to a LED light module according to the preamble of the main claim.

Such a module is from the DE 10 2009 052 340 A1 known for use in the lighting device of a motor vehicle. There is provided, in the effort of standardization, the different LEDs available on the market not to be mounted on each individually adapted support element and connect it, but instead interpose a otherwise uniformly designed small circuit substrate for receiving the LED. This circuit carrier can be mounted with a standardized connection design on the support element and at the same time thermally conductive directly on a heat sink, which is partially surrounded in the plastic injection molding of the support element. A molded into the carrier element conductor is used with a linear projecting therefrom wire end as a connection pin and with its opposite, cranked out of the sprue extending wire end of a contact on the edge of the exposed surface of said LED circuit substrate. However, insofar as an individual such circuit carrier must be provided for each type of LED, it is hardly possible to achieve a standardization effect as a result; while on the other hand, the manufacturing and logistical effort as a result of the need individually adapted to the LED circuit board increases noticeably.

After DE 10 2008 026 627 B3 has designed as a heat sink multilayer printed circuit board over a stack of sheets that are accessible due to terrace-like gradation of about a circuit board edge for mounting and bonding each one of a plurality of LED chips on its associated layer.

A designed as a light metal extruded heat sink for high-power LEDs is according to the DE 20 2013 001 467 U1 connected in plastic injection molding with a mounting part, but the LED is directly or by means of a printed circuit board, electrically insulating but thermally conductive, mounted directly on the heat sink. On a PCB wiring or on an electrical connection to electrical food the LED is not discussed.

In the from the DE 10 2010 048 595 A1 For use in a motor vehicle headlight known light module has this as a heat sink for a high-performance light emitting diode (LED) on a manufactured with powerful ribs heat sink. On a contact plate is screwed from insulating material, which in turn is equipped with the light-emitting semiconductor diode and a punched grid to the power supply. The process chain from such a large number of manufacturing steps requires special logistical effort to mount the numerous individual parts of the light module and as a result its resulting susceptibility to malfunction.

In recognition of such circumstances, the present invention is based on the technical problem of reducing costs by shortening the traditional process chain and nevertheless increasing manufacturing reliability.

This object is achieved by the essential features specified in the main claim; wherein for the sake of simplicity of illustration always only one light module with an LED is mentioned, although in the context of the present invention, an equipment with multiple LEDs equally comes into consideration.

Again, the LED can be mounted on a small circuit board; and you, made of good thermally conductive material such as metal, preferably in the die casting made of light metal heat sink is in turn at least partially encapsulated with an electrically insulating plastic enclosure. The pins accessible from outside the light module for contacting are now in particular shot or separated from a cast-in stamped grid. Parallel to each other distanced from the electrically insulating enclosure outstanding free ends of the pins, such as a stamped grid are surrounded by a plug basket as a mechanical protection, which is preferably formed of the enclosure. The pins are used in particular as pins for external power to the LED. For the rear end portions of these pins, such as end face or longitudinally angled course, accessible on the surface of the enclosure for contacting.

From those pin ends, towards the LED, now extend cable runs, which are inventively printed or, preferably, pasty, in particular thermosetting conductive material applied approximately by means of a hollow needle. In crossing areas, to avoid short circuits, one of the cable runs is offset in height relative to the other, in particular as a result of running through a groove sunk into the surround surface.

The enclosure of the heat sink has a plastic at least partially penetrating recess in front of a surface region of a belt extending over cooling ribs. This can be bridged by a resting on the mount LED board, when filling the space under the board with thermally conductive, preferably pasty and adhesive material.

A more compact construction results when a board equipped with the LED is mounted in the mentioned recess, namely practically sunk down to the usually metal heat sink. If necessary, there is a heat-conducting electrical insulating layer under the board. As that can also serve as a spray skin, which closes the recess in the plastic-molded enclosure as a floor. To avoid heat-insulating cavities, it is expedient, above and at least under the insulating layer, and optionally in a the insulating layer crossing opening to introduce a commercially available thermal paste, which preferably also has adhesive properties.

Even more practical in terms of logistics and construction volume is a direct mounting of the LED, so without an intermediate carrier in the form of a circuit board. Particularly suitable for this purpose is a LED of the high-performance type, which is already equipped with an integrated but electrically insulated cooling contact. The can be mounted directly on a surface of the heat sink by means of a Wärmeleitklebers. The electrical contacting of the LED is possible via printed conductors, which are guided over the surface of the plastic enclosure, or over the surface of the metal heat sink with the interposition of an insulation, for example in the form of strands of electrical insulating paste.

By such application of the LED on the heat sink eliminates the separate assembly and screwing a circuit board or the like contact plate of known type for the installation of the LED. The LED is by means of the current-carrying lines directly to the enclosure of the heat sink or in the enclosure, preferably with an intermediate layer a thermally conductive electrical separation layer, mounted on the heat sink and energized.

The determination of the LED or possibly its board is, as mentioned above, preferably cohesively, for which the electrical conductive material can serve as an adhesive. As such conductive adhesive is about silicone with inorganic, electrically conductive fillers use. Certain metallic fillers (such as in particular silver or nickel) lead to an electrically conductive adhesive which also conducts heat well.

Additional refinements and modifications in the context of the present invention will become apparent from the other claims and also taking into account the advantages thereof, from the following description of the drawing in which limited to the functional essentials strongly abstracted and not to scale outlined preferred embodiments of the invention. The drawing shows a partially thermally molded with a thermally and electrically insulating plastic enclosure heat sink made of good heat conducting material in

1 with mounted on the bezel LED board and in

2 with sunken in the enclosure LED board, each in cross-sectional view; as well as in view with aborted representation in

3 with modified sunken LED board and in

4 with PCB-less mounting of the LED on its heat sink.

A heat sink designed to increase the surface area with strong ribs on a belt extending across the belt 11 a light module 12 is with a mount supporting its mounting 13 made of electrically non-conductive plastic at least partially encapsulated, so that the heat sink 11 and its surround 13 preferably are positively connected with each other. A local side projection 14 of the mount 13 over the edge of the heat sink 11 addition is to a plug basket 15 shaped. In the protrude from the supernatant 14 fro pins 16 into it, at a later to be cut punched grid 17 are free. That's here in the supernatant 14 poured, causing its pins 16 are positioned and held. The pencils 16 but also after the casting of the enclosure 13 be pressed into the bottom of the plug basket or inserted into it freigesparte holes. The end sections located at the bottom 18 of the pens 16 are on the surface 19 of the mount 13 , beveled running or simply end face, accessible to contacts by means of conductive adhesives.

On the surface 19 of the mount 13 , or in grooves introduced therein, are cable runs 20 printed from electrically conductive material or, preferably applied pasty. Anyway, some of them extend from the end sections 18 of the pens 16 up to a recess 21 after the design 1 and 2 the material of the mount 13 until possible on the outer surface 22 of the heat sink 11 traversed approximately like a hollow cylinder. Instead of such pasty cable trains 20 , or in addition to them, can as in 2 considered, even such long pin end portions 18 be provided that they, at the mount surface 19 angled parallel to this, approximately in the direction of the recess 21 run out.

At least one LED 23 preferably high light output is with their connections on conductor tracks 24 a circuit board 25 mounted in 1 in at least one orientation the diameter of the recess 21 surmounted. Here are the tracks 24 with the cable trains 20 , or possibly directly with pin end sections 18 , contacted. If pasty cable trains 20 down to the board 25 extend, this is due to their adhesive properties at the same time with the edging surface 19 cohesively connected. It is not shown graphically that it can be useful for securing against vibration influences or similar mechanical alternating stresses, for example, the circuit board 25 additionally on the mount 13 , or through it on the heat sink 11 , to screw or otherwise in particular form-fitting set.

The positioning of the board 25 on the edge of the recess 21 is suitably by ring or pillar-shaped axial spacers 26 conveyed along this edge, so that the pasty cable runs 20 with their given strength to below the edge of the board 25 can extend. There they then serve, if necessary via passages, the electrical contact with the circuit board conductor tracks 24 and at the same time as a material connection between the board 25 and the surround surface 19 ,

The recess 21 is between the resting board 25 and the heat sink outer surface 22 advantageously with the best thermal conductive material as thermal bridging 27 from the LED 23 to her heat sink 11 filled. The adhesion of such Thermoleitpaste causes a convenient additional material connection between LED 23 and heat sink 11 , When as a spacer 26 one at the mount 13 There is a continuous circumferential, hollow cylindrical wall, then forms an insulation between the cable trains 20 outside and the recess 21 within such peripheral wall; so that, in the absence of risk of short circuit, in the recess 21 as a thermal bridge and glue the same pasty material can be used as over the enclosure 13 away for the electrical wiring 20 to the pin end sections 18 ,

The training after 2 The drawing provides the advantage of an even flatter construction, because now the LED board 25 in a surround recess 21 sunken or as sketched next to the border 13 on the heat sink 11 is arranged. At the transition of a pasty cable train 20 from the mount surface 19 to the board 25 its edge should be as gap-free as possible flush against the adjacent edge of the enclosure 13 issue. Because in a gap could conductive paste of the cable train 20 penetrate and an unwanted electrical connection from the cable 20 to the metallic heat sink 11 to lead.

Preferably, in an arrangement according to 2 between the heat sink 11 and the board 25 a thin heat-conducting electrical insulating layer 28 , This can be used as a paint on the heat sink outer surface 22 be applied, which then with its curing at the same time a cohesive connection between the LED-equipped board 25 and the heat sink 11 he brings.

The in 3 Outlined construction corresponds to that according to 2 than the LED 23 on a circuit board 25 mounted, in turn, in one, the geometry of the board 25 corresponding, recess 21 in the mount 13 is sunk, which is the heat sink 11 partially surrounds. For the energization of the LED 23 run printed circuit traces 24 of connection surfaces 29 on the board 25 over the bordering surface 19 to the pin end sections 18 behind the plug basket 15 ,

The least amount of parts to be mounted falls in the development of the light module according to the invention 12 according to 4 at. Again, the coarse ribbed (not shown) heat sink 11 partly from an encapsulated mount 13 surrounded, to which the plug basket 15 is molded from the rear pin end portions 18 are accessible. The LED 23 is with electrically insulating thermal adhesive on the heat sink 11 assembled. From the LED 23 extend over the heat sink outer surface 22 towards the end sections 18 to feel 30 from electrical insulation paste, which are applied for example by means of a nozzle. The paste-like insulating material traces 30 can on the edge of the mount 13 end or, as outlined above its surface 19 to the pin end sections 18 run. On these insulating material traces 30 - and then optionally on the border 13 - are finally the actual conductive adhesive cable tracks 20 applied. The rest elasticity of the support in the form of the cured insulating material traces 30 Good protection against any cable break due to mechanical or thermal cycling.

In a light module 12 with at least one LED 23 on a heat-conducting, in particular metal and preferably pressed from light metal heat sink 11 This is thus according to the invention in plastic injection at least partially by him receiving a form-fitting mount 13 Surrounded with plug pins 16 is equipped. The LED 23 is by means of thermal adhesive on the heat sink 11 mounted, optionally on or in a recess 21 that in the mount 13 freed or incorporated into this. In different levels intersecting pasty cable trains 20 electrically conductive adhesive in the course of electrical connections between pins 16 and LEDs 23 can on tracks 30 from electrical insulation paste over the heat sink 11 run away. This leads to a considerable reduction in the space required for the light module 12 and the effort for its assembly.

LIST OF REFERENCE NUMBERS

11

Heat sink (for 23 )

12

Light module (with 11 and 23 )

13

Mount (from 11 )

14

Supernatant (from 13 above 11 addition)

15

Plug basket (at 14 )

16

Pen (in 15 , for example 17 )

17

Punching grid (for 16 ; in 14 )

18

End section (from 16 Behind 15 )

19

Surface (from 13 )

20

Pasty cable runs (between 18 and 23 )

21

Recess (in 13 )

22

Outer surface (from 11 )

23

LED (from 12 )

24

Printed circuit traces (on 25 )

25

Board (with 24 and 23 )

26

Spacer (between 25 and 19 )

27

Bridging (under 25 , to 22 )

28

Insulating layer (on 22 )

29

Terminal surface (on 25 )

30

pasty trace (under 20 )

Claims (10)

Light module ( 12 ) with at least one LED ( 23 ), the electrically insulating but heat-conducting on a heat sink ( 11 ) mounted at least in part by one with pins ( 16 ) equipped mount ( 13 ) is surrounded by plastic, characterized in that in the course of electrical connections between the pins ( 16 ) and the LED ( 23 ) pasty cable trains ( 20 ) provided over the outer surface ( 22 ) of a metal heat sink ( 11 ) on tracks ( 30 ) run from electrical insulating paste. Light module according to the preceding claim, characterized in that conductive adhesive cable tracks ( 20 ) on insulating material traces ( 30 ) are applied, which, cured, have a residual elasticity. Light module according to one of the preceding claims, characterized in that one with the LED ( 23 ) equipped board ( 25 ) against an adjacent border of the enclosure ( 13 ) lying on the heat sink ( 11 ) is mounted. Light module according to one of the preceding claims, characterized in that the enclosure ( 13 ) a recess ( 21 ), over or in which a circuit board ( 25 ) with the LED ( 23 ) is mounted. Light module according to the preceding claim, characterized in that between the in the recess ( 21 ) recessed board ( 25 ) and the heat sink outer surface ( 22 ) a heat-suffering bridging ( 27 ) is provided. Light module according to one of the two preceding claims, characterized in that between the board ( 25 ) and the outer surface ( 22 ) of the heat sink ( 11 ) an electrical insulating layer ( 28 ) is provided, which is the bottom of a cup-shaped recess ( 21 ) can act. Light module according to one of the three preceding claims, characterized in that the board ( 25 ) via a spacer ( 26 ) on the surface ( 19 ) of the enclosure ( 13 ) rests. Light module according to the preceding claim, characterized in that the board ( 25 ) on a spacer ( 26 ) in the form of a recess ( 21 ) rests on surrounding wall. Light module according to one of the preceding claims, characterized in that at least one of the cable runs ( 20 ) as the rear end portion ( 18 ) one of the pens ( 16 ) is trained. Light module according to one of the preceding claims, characterized in that the frame ( 13 ) a plug basket ( 15 ) for the pens ( 16 ) is formed.

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