EP2766657B1 - Led module with a heat sink - Google Patents

Description

Technical area

The invention relates to a lighting device comprising at least one light module and at least one light module carrier, wherein the light module carrier is provided for heat dissipation from the light module

State of the art

Lighting devices, in particular those in which semiconductor light sources, such as LEDs, are used to generate light, are often modular, ie, there are different modules with different functions. Of central importance here are the so-called lighting modules, ie the modules that essentially carry the actual light sources. These modules should be easy to install, but at the same time be held reliably and have a good heat transfer to the underlying light module carrier in order to dissipate the heat generated during operation of the light sources reliably. Usually, the lighting modules are screwed or glued to the light module carrier, so that the mechanical contact is ensured. However, a disadvantage of an adhesive connection is that the module can only be removed from the support with difficulty or not at all. In contrast, with a screw or rivet connection, the light module can indeed be easily separated from the carrier, but it is fixed by the screws on the screw holes so that it is heated due to the different thermal expansion of the modules and the carrier can lead to a bulging of the light module, so that the thermal connection to the carrier is deteriorated or interrupted and the module can overheat. Also can be done by the bulge mechanical damage to the module. In order to improve the thermal contact between the light module and the module carrier, a so-called "Thermal Interface Material" (TIM) is often introduced between the light module and the light module carrier, which improves the thermal contact, in particular by compensating for unevenness. However, this is expensive and can no longer ensure the thermal contact at too large bulging of the module.

The WO 2004/071143 , the WO 2009/121439 and the US 2008/0130275 A1 each show brackets for LED-bearing boards, in which they are pressed by means of spring elements on a support.

The registration letter US 2011/0069502 A1 discloses a mounting device for a LED-supporting board. The board is pressed by means of spring forces against a heat-conducting surface of the mounting device.

Presentation of the invention

The object of the present invention is to enable a secure and reliable, but with simple means detachable attachment of a light module on a light module carrier, the cooling of the light module is to be ensured in all operating situations.

This object is achieved by characterizing features of claim 1.

Particularly advantageous embodiments can be found in the dependent claims.

In that at least a first fastening element is provided for fastening the lighting module on the light module carrier, wherein the first fastening element is designed such that the lighting module with a defined Pressing force is pressed onto the light module carrier such that a defined heat transfer between the light module and light module carrier is made possible, a good heat dissipation is achieved. The fact that in the region of the first fastener movement of the light module, in particular a thermal expansion, parallel to the main plane of the light module is possible, it is avoided that the light module carrier bends or tears with increasing heating. A good heat transfer is given in particular if the contact resistance at the transition surface from the light module to the light module carrier is not more than 20,000 m ² K / W, preferably not more than 5,000 m ² k / W. By the contact force is chosen such that on the heat transfer surfaces a pressure between 0.002 N / mm ² and 1.0 N / mm ² , preferably between 0.05 N / mm ² and 0.5 N / mm ^{2, more} preferably between 0, 08 N / mm ² and 0.3 N / mm ² , in particular from approximately 0.1 N / mm ² to 0.2 N / mm ^{2 is} exercised, in the usual conditions of such a system, both a good heat transfer is possible, as also a is a good solubility of the compound in the case of an exchange of the light source. In particular, printed circuit boards or substrates with light sources arranged thereon are to be regarded as lighting modules, although other components such as connecting devices such as plugs or soldering tags, electronic circuits or individual components may also be provided.

By at least one second fastening element is provided, which the light module carrier on at least one Fixed location in the region of the second fastener, on the one hand ensures that the light module is securely positioned, which may be important for accurate beam guidance of the emitted light, for example, in relation to optical means such as reflectors or lenses, and on the other hand due to the mobility in the first fastener no Inadmissible mechanical stress occurs. It is thus achieved a certain division of tasks between the fasteners, ie, the at least one first fastener is used to apply a defined contact force to allow a good heat transfer to the light module carrier, while the at least one second fastener is used for mechanical positioning.

By the second fastening element comprises at least one screw and / or at least one rivet, the light module is set in its position in a particularly simple manner, for example, by a screw hole is provided with the diameter of the screw in a circuit board of the light module and in the light module carrier a threaded hole for Pick up the screw.

It may also be advantageous if the lighting module is fixed in a defined area by means of an adhesive connection. This area expediently occupies only a small part, in particular less than 20%, of the area in contact with the luminous module carrier, for example in the case of a rectangular module an area adjoining the narrow side.

In general, it is advantageous if the second fastening element and the first fastening element are spaced apart by more than 50% of the length of the lighting module, measured in the direction between the fastening regions, since the effect of the thermal expansion of the lighting module is particularly great with a wide spacing of the fastening regions is great.

Conveniently, the first fastening element comprises at least one spring element. Spring elements are particularly suitable to apply a defined force while still be able to compensate for dimensional tolerances. This allows both a sufficiently firm contact for an optimized heat transfer, as well as avoids excessive pressing and ensures the desired mobility of the light module. Also, a release of the connection is easily possible again.

By the first fastening element comprises at least one stamped part, in particular formed as a stamped part, a simple production is possible.

The production is particularly simple if the stamped part is designed as a stamped spring plate.

It is advantageous if the spring element has at least one first fastening region for attachment to the light module carrier and at least one spring arm for applying the contact pressure force to the lighting module. This is a particularly simple structure that can be easily manufactured, for example, with stamped parts.

In that the spring element has at least one second fastening region for attachment to the light module carrier has, a particularly good attachment can be achieved.

By virtue of the second fastening region being in the form of the second fastening element or comprising the second fastening element, it is possible with a single component to achieve fixing of the lighting module at one point and a displaceable fastening elsewhere. This reduces the installation effort.

Advantageously, the first attachment region and the second attachment region are connected by means of at least one bridge. As a result, a simple production and assembly is possible.

By the bridge comprises at least one spring element and / or is designed as at least one spring element, a particularly simple construction is achieved, in which the number of required parts can be minimized.

In an advantageous embodiment, the bridge between the two attachment areas on at least one attachment point for the application of force to the light emitting module. Thereby, the introduction of force can be particularly advantageous at the areas of the light module where it is needed.

Furthermore, it is advantageous if the first fastening element has at least one fixing means for limiting the movement of the light module. Thereby, a movement within defined limits is possible, so that, for example, a sufficiently accurate positioning of the lighting module in relation to an optical means, such as a reflector, can be realized, and yet a sufficient extension of the light module is possible to avoid unwanted deformation or detachment of the module from the carrier.

By the first fastener has a substantially U-shaped geometry, a particularly simple production is possible. In particular, the arc U can serve as a mounting area for the attachment of the first fastener to the light source carrier, while the two legs of the U as a pressure element, for example in the form of a spring element, press the light module on the light module carrier.

In a further advantageous embodiment, the first fastening element essentially has a frame-shaped geometry. This is a simple construction, which can be used advantageously in particular with fastening elements with two attachment areas, since these are arranged, for example, on opposite sides of the frame, while the connection of these sides takes place by means of two bridges, between which the light sources of the lighting module are arranged.

Semiconductor light sources, in particular light emitting diodes (LED) or organic light emitting diodes (OLED), are preferably used as light sources. These offer a high luminous efficacy and benefit especially from a good cooling, as their lifetime and color fidelity increases.

It is also advantageous if the light module carrier is designed as a heat sink, as this achieves a simple structure and the cooling of the light sources is optimized.

It may also be advantageous if the light module carrier is designed as a housing part of a lamp. As a result, a particularly simple construction is achieved and the luminaire housing can be used for cooling.

Even if it is usually possible to dispense with a TIM between the light module and the light module carrier, in some applications such a material between the light module and the light module carrier may also be advantageous in order to further improve the thermal transition.

Advantageously, a series of first attachment means is provided, wherein different attachment means of the series have a substantially identical first attachment region. As a result, the light module carrier when using different fastening means, as required for example when using different light modules, each be the same design and the adjustment is made by selecting the appropriate fastener.

In particular, it is expedient if, in the series of fastening means, different fastening means of the series have essentially the same geometry and differ in the strength of the contact pressure exerted on the lighting module. As a result, with an otherwise unchanged geometry of the lighting module and the lighting module carrier, the contact force can be adapted to the intended use, ie a lower contact pressure can be selected, for example, with lighting modules with low heat development than those with high heat development.

Brief description of the drawings

Fig. 1

ein erstes Ausführungsbeispiel der Erfindung in einer perspektivischen Gesamtansicht, in einer perspektivischen Detailansicht sowie einem Querschnitt,

Fig. 2

ein zweites Ausführungsbeispiel der Erfindung in einer perspektivischen Gesamtansicht, in einer perspektivischen Detailansicht sowie einer Seitenansicht,

Fig. 3

ein drittes Ausführungsbeispiel der Erfindung in einer perspektivischen Gesamtansicht, in einer perspektivischen Detailansicht sowie einer Seitenansicht,

Fig. 4

ein viertes Ausführungsbeispiel der Erfindung in einer perspektivischen Gesamtansicht, in einer perspektivischen Detailansicht sowie einer Seitenansicht,

Fig. 5

ein fünftes Ausführungsbeispiel der Erfindung in einer perspektivischen Gesamtansicht, in einer perspektivischen Detailansicht sowie einer Seitenansicht.

In the following, the invention will be explained in more detail with reference to exemplary embodiments. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity. The figures show:

Fig. 1

A first embodiment of the invention in an overall perspective view, in a perspective detail view and a cross section,

Fig. 2

A second embodiment of the invention in a perspective overall view, in a perspective detail view and a side view,

Fig. 3

A third embodiment of the invention in an overall perspective view, in a perspective detail view and a side view,

Fig. 4

A fourth embodiment of the invention in an overall perspective view, in a perspective detail view and a side view,

Fig. 5

a fifth embodiment of the invention in an overall perspective view, in a perspective detail view and a side view.

Preferred embodiment of the invention

FIG. 1 shows a first embodiment of a lighting device 100 according to the invention in an overall perspective view, in a perspective detail view and a cross section. A rectangular light module 120 is arranged on a light module carrier 110, wherein the light module 120 LEDS 130 as light sources and a connector 140 for electrical contacting has. The lighting module 120 is fastened with a frame-shaped first fastening element 145 on the light module carrier 110, which has two fastening regions 150, 160, which are connected by means of two bridges 170. The first fastening region 150 represents a first frame side of the fastening element 145 and has two screw holes 180, by means of which it can be screwed onto the light module carrier 110 with screws, not shown here for the sake of clarity. The second fastening region 160 also has two screw holes 180, by means of which the fastening element 145 is connected to the light module carrier 110 by means of two screws, not shown here, and thus also fixes the light module 120 at this point. The screws and the second fastening region 160 thus form a second fastening element 165, which is formed as part of the first fastening element 145. At the bridges 170 spring arms 190 are arranged, which act on the light module 120 and press this with defined contact pressure on the light module carrier 110. The fastener 145 is stamped out of a spring plate, which allows a particularly simple production. Due to the large number of spring arms 190 is the Distributed contact force distributed, which ensures a uniform contact force and thus a uniform heat transfer. The spring arms 190 are rounded in the region of the support on the light module 120, which facilitates the mounting of the lighting device 100 and also facilitates a movement of the light module 120. During operation of the light-emitting module, this is heated in the region of the light-emitting diodes 130 and expands. Since it is fixed in the second fastening region 160, the expansion preferably takes place in the direction of the first fastening region 150. Since the spring arms 190 does not substantially hinder the light-emitting module 110 in its thermal expansion, the support on the light-module carrier 110 remains in the desired force.

In FIG. 2 a further embodiment of a lighting device 200 according to the invention is shown. The light module 220 is held on the light module carrier 210 by means of a first fastening element 245, also punched out of spring plate. As a second fastener not shown screws are used in the screw holes 285, which fix the light module 220 at this point. The first fastening element 245 is U-shaped and has a first fastening region 250 in the arc of the U, in which a screw hole 280 for receiving a screw, not shown here, is provided in order to fix the fastening element 245 on the light module carrier 210. The legs of the U are designed as spring arms 290 which press the light module 220 with a predefined force on the light module carrier in order to ensure the desired heat transfer. Again, when heating the light module 220 this fixed to the screw holes 285, while an extension in the direction of the first mounting portion 250 is possible. In order to minimize friction here, the spring arms are rounded in their attachment point 295. The lighting module 220 here still has mounting holes 299, which can alternatively be used for a screw connection of the module according to the prior art, ie the solution shown is suitable (as well as the other embodiments) for retrofitting existing lighting devices.

FIG. 3 shows a further embodiment of an illumination device 300 with a light emitting module 320 on a light module carrier 310, in which case the first fastening element 345 is formed like a frame shape analogous to the first embodiment. However, the first attachment region 350 has only one central screw hole 380 analogous to the second embodiment. The second mounting portion 360 is analogous to the first embodiment formed with screw holes 385 in which by means not shown screws, the light module 320 is fixed and thus forms a second fastener 365. In contrast to the previous embodiments, the bridges 370 are themselves designed as spring arms 390 and have two attachment points 395 on each side. An advantage of this construction over the first embodiment is the simpler production, since fewer spring arms are needed and these are part of the bridges 370 and compared to the second embodiment, that a better distributed force is applied and this also by the frame construction can be made more reliable than with a U-shaped design.

FIG. 4 shows a further, particularly simple embodiment of a lighting device 400, in which the lighting module 420 is analogous to the first and third embodiments on the light module carrier 410 by means not shown screws in screw holes 485 is fixed on one side and held on the other side by means of a strip-shaped fastener 445. The fastener 445 has a first mounting area 450 with a screw hole 480 from which spring arms 490 extend on both sides. The spring arms 490 are located in the edge region of the light module 420 and press this defined on the light module carrier 410. In order to additionally provide a mechanical fixation, 490 Haltedome 498 are imprinted in the spring arms, which is too extensive displacement of the light module 420 by engaging in the screw holes 499 intervene. These screw holes 499, analogous to the module in the second embodiment, already be present in modules according to the prior art, but it is also possible that modules are specifically provided for this purpose with such holes.

FIG. 5 shows a variant of the second embodiment, which differs essentially only by the configuration of the lighting module 520, since this now no more screw holes 299 and thus has a more compact design. Fixation by means of screw holes 585 is analogous to those in the second embodiment via the holes 285, as well as the pressure by means of the fastener 545 is analogous to that in the fastener 245, namely by spring arms 590, wherein the fastener 545 at a first mounting portion 550 by means of a screw in the screw hole 580th is held. The rounding of the spring arms 590 to the attachment point 595 is carried out the same. The two fastening elements 545 and 245 can be regarded as representatives of a series of fastening elements which have the same geometric basic shape, but have different heights d for adaptation to different geometries of lighting modules 220, 520, so that differently high lighting modules 220, 520 with the same spring force could be applied, or equally high light modules 220, 520 with different spring force.

In particular, the fasteners 245, 445 and 545, which are held with only one screw, could additionally have elements that prevent twisting when tightening, such as retaining lugs, which engage in a recess in the light module carrier 210, 410, 510.

If the contact pressure of the spring arms 190, 290 be changed in the illustrated fasteners 145, 245, for example, in the context of a series of fasteners spring arms of different spring constants are used or a Vorbiegung of the spring arms 190, 290 are varied, so that depending on the application, the appropriate Fastener can be selected.

Of course, other variants of the invention will be apparent to those skilled in the art, for example, by a combination of elements of the embodiments, which could not be shown here. The embodiment of the light module carrier can be done for example as a dedicated heat sink or as part of a light housing. For the construction of the light module and the light sources used there are also known in the art a variety of ways such as the use of plastic or metal core boards or various LEDs. The geometry of the light modules may differ, for example, differ in the aspect ratios or completely different shapes such as triangles or circles come as a basic form in question.

Claims (11)

1. Illuminating device (100, 200, 300, 400, 500) comprising at least one lighting module (120, 220, 320, 420, 520) and at least one lighting module support (110, 210, 310, 410, 510), wherein the lighting module support (110, 210, 310, 410, 510) is provided in order to dissipate heat from the lighting module (120, 220, 320, 420, 520) and at least one first fastening element (145, 245, 345, 445, 545) for fastening the lighting module (120, 220, 320, 420, 520) on the lighting module support (110, 210, 310, 410, 510) is provided, wherein the first fastening element (145, 245, 345, 445, 545) is designed in such a way that the lighting module (120, 220, 320, 420, 520) is pressed with a defined pressing force onto the lighting module support (110, 210, 310, 410, 510) in such a way that a defined transfer of heat between the lighting module (120, 220, 320, 420, 520) and lighting module support (110, 210, 310, 410, 510) is enabled, and, in the region of the first fastening element (145, 245, 345, 445, 545), a movement of the lighting module (120, 220, 320, 420, 520) parallel to the main plane of the lighting module (120, 220, 320, 420, 520) is enabled, wherein at least one second fastening element (165, 365) is provided, which fixes the lighting module (120, 220, 320, 420, 520) and the lighting module support (110, 210, 310, 410, 510) at least at one point in the region of the second fastening element (165, 365), characterized in that the first fastening element (145, 245, 345, 445, 545) comprises at least one punched part, wherein the punched part is formed as a punched spring steel sheet.
2. Illuminating device (100, 200, 300, 400, 500) according to Claim 1, wherein the second fastening element (165, 365) comprises at least one screw and/or at least one rivet.
3. Illuminating device (100, 200, 300, 400, 500) according to either of Claims 1 and 2, wherein the first fastening element (145, 245, 345, 445, 545) comprises at least one spring element.
4. Illuminating device (100, 200, 300, 400, 500) according to Claim 3, wherein the spring element comprises at least one first fastening region (150, 250, 350, 450, 550) for fastening on the lighting module support (110, 210, 310, 410, 510) and at least one spring arm (190, 290, 390, 490, 590) for applying the pressing force to the lighting module (120, 220, 320, 420, 520).
5. Illuminating device (100, 200, 300, 400, 500) according to Claim 4, wherein the spring element comprises at least one second fastening region (160, 360) for fastening on the lighting module support (110, 210, 310, 410, 510).
6. Illuminating device (100, 200, 300, 400, 500) according to Claim 5, wherein the first fastening region (150, 350) and the second fastening region (160, 360) are connected by means of at least one bridge (170, 370).
7. Illuminating device (100, 200, 300, 400, 500) according to Claim 6, wherein the bridge (170, 370) comprises at least one spring element (190, 390) and/or is formed as at least one spring element (190, 390).
8. Illuminating device (100, 200, 300, 400, 500) according to either of Claims 6 and 7, wherein the bridge (170, 370) comprises, between the two fastening regions, at least one contact point for introducing force onto the lighting module (120, 220, 320, 420, 520).
9. Illuminating device (100, 200, 300, 400, 500) according to one of Claims 1 to 8, wherein the first fastening element (445) comprises at least one fixing means for delimiting the movement of the lighting module (120, 220, 320, 420, 520).
10. Illuminating device (100, 200, 300, 400, 500) according to one of Claims 1 to 9, wherein the first fastening element (245, 545) has a substantially U-shaped geometry.
11. Illuminating device (100, 200, 300, 400, 500) according to one of Claims 1 to 10, wherein the first fastening element (145, 345) has a substantially frame-shaped geometry.

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