WO2014076131A1

WO2014076131A1 - Light-emitting module comprising a cooling module

Info

Publication number: WO2014076131A1
Application number: PCT/EP2013/073724
Authority: WO
Inventors: Ernst HELLDORFF
Original assignee: Helldorff Ernst
Priority date: 2012-11-14
Filing date: 2013-11-13
Publication date: 2014-05-22

Abstract

The invention relates to a light-emitting module, comprising a cooling module (1) which consists of a basic body (6), on which a plurality of cooling structures are formed integrally, which cooling structures are formed at least partially as projections (7), which protrude from the basic body (6) substantially parallel to the emission direction (5), wherein an area which is free from cooling structures is provided on the cooling module (1), on which area at least one LED module (2) for at least one light-emitting diode (3a, 3b, 3c, 3d) is fitted, which light-emitting diode has an emission direction (5) corresponding to the projections (7). Improved cooling can be achieved by virtue of the fact that the projections (7) are formed corresponding to thermally optimized freeform areas. The invention also relates to a light-emitting module comprising a cooling module (1), which consists of a basic body (6) on which a plurality of cooling structures are formed integrally.

Description

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Light module with a cooling module

The invention relates to a lighting module with a cooling module, which consists of a base body, on which a plurality of cooling structures are formed, which are at least partially formed as projections, wherein the cooling module is provided a free surface of cooling structures and at least one LED module for at least one light emitting diode is mounted, and wherein the lighting module has a projection approximately corresponding emission direction.

As a cooling module in the above sense units are understood that consist of a heat sink and cooling structures, usually a mounting surface is provided for at least one LED module, which functionally represents the light source and carries at least one LED.

As a cooling module in the context of the invention, multi-part structures are understood, for example, plates on which the cooling structures are not integrally formed, but individually or in groups are added.

As cooling structures in the above sense, thermally optimized structures are understood, which are provided with projections in the general sense to derive the heat generated by the LED module. As LED module here the support structures of the LEDs are understood.

As light-emitting diodes in the above sense, various types of light sources are understood, which have in common to emit "cold light", such as LEDs and OLEDs (organic light-emitting diodes). This means that the visible light and heat are emitted with different radiation characteristics and in different directions. This is different from other bulbs such as incandescent lamps, halogen lamps and gas discharge lamps in which light and heat are radiated in the same direction.

Due to their high degree of efficiency, LED luminaires prevail in many areas, for example in street lighting. Although LED lamps produce less heat compared to other bulbs, the cooling of such lamps is critical. This is due to the fact that both the efficiency and the lifetime of the LEDs decrease sharply with increasing temperature.

Also, the various electronic assemblies, such as the PCBs, which also supply the light sources, are heated by the heat emitted by the light source (LED, etc.) and must be as efficient as - - possible give off this heat to avoid damage to the light sources or the electronics.

Due to this technologically related behavior of the light sources, there is the need to dissipate the heat either via heat-absorbing or the heat-conducting elements or modern coating technologies in the direction of the lamp housing, or to the cooling structures.

The solution of the heat dissipation is also so important because the efficiency and life of light emitting diodes are determined by the optimal interaction of the elements electronics, light source technology and thermodynamics, with a thermal dissipation inefficiency for a given electronic and lighting performance to a reduced light output of up to 15% and a lifetime shortening by up to 50%.

Basically, various approaches are currently known to solve the problem of heat dissipation:

Cooling fins on top of the luminaire;

Air gaps between the individual light bands; technical design of the light unit, so that the cool air passes sideways; correspondingly optimized cooling surfaces on top of the luminaire housing.

Upwardly projecting cooling fins, on the one hand, are prone to contamination and are also expensive to clean. On the other hand, these are in the typical installation position in the lee of the thermal convection flow, which is caused by the waste heat of the lamp.

A partial solution to these problems is achieved with a light source, as described in US 2012/0163003 A. Therein a light-emitting means is described, which has two-sided cooling structures around the LEDs, which are designed as downwardly directed cooling fins and as upwardly directed cooling pins.

This light source is intended to be installed in a lamp, the directed into the inside of the lamp cooling pins of the bulb cause undesirable heating and heat accumulation inside the lamp and so additionally burden the electronics and the LEDs themselves undesirable. - -

In an arrangement of the lamp outdoors, such as in a street lighting, the cooling effect is also supported by any occurring wind. The particular disadvantages of a cooling module provided with cooling fins can be summarized as follows:

- Warm air generally rises and leads to a build-up of heat in the slats, which leads to heating instead of cooling. This negative effect can only - as described in the previously published document - be overcome by additional ventilation holes, since in this case, the rising heat is passed through the lamp and similar to a chimney effect, the heat can be dissipated until there is also a build-up of heat and on the Top of the lamp housing must be radiated. However, ventilation holes in the luminaire have the significant disadvantage that in this way vermin and other contaminants can penetrate into the luminous element, which is in contradiction to the standards such as protection class IP 65.

- If the winds blow substantially parallel to the plane of the cooling fins, the interstices are well flowed through and it can be achieved an improved cooling. Otherwise, however, the heat is jammed in the spaces and there is insufficient cooling. This is also the case with the abovementioned already known solution.

The above disadvantages are partly avoided by a solution as described in US 2008/0144318 A. On a flat underside of a lamp body are thereby mounted around the illuminant vertically downwardly projecting pins as a heat sink. It has been found that with such a design, depending on the prevailing flow conditions, more or less strong vortices are formed and that these also cause poorly perfused zones of the surface. Overall, this leads to a suboptimal heat dissipation.

Similar disadvantages are also noted in a heat sink arrangement described in US 6,390,181 B.

The object of the present invention is to avoid these disadvantages and to provide a solution with which improved cooling without soiling the interior of the luminaires (IP 65 compliant) can be achieved.

According to the invention, these objects are achieved in that the projections are designed according to thermally optimized free-form surfaces. - -

In the context of the invention, thermally optimized free-form surfaces are primarily surfaces that are largely or completely free of edges and abrupt transitions. This applies both to the surfaces themselves, which are smooth or gently curved, as well as arranged on the surfaces projections which merge at their base via curves in the surfaces and which in turn are rounded to the top.

The solution according to the invention ensures that the thermal convection flow also simultaneously drives the flow around the cooling structures, possibly occurring wind can improve the cooling irrespective of the wind direction and the anyway required cleaning of the luminaire or of the illuminant can be applied to the adjoining one without significant additional expenditure Cooling structure to be extended.

Important in the context of the present invention is the formation of the cooling structures using free-form surfaces. As a result, poorly flowed areas can be avoided even in different wind directions, whereby a corresponding improvement of the heat dissipation is achieved.

A particular advantage of the inventive solution is that there is currently a switch from previously used mono-LED chips on multi-LED chips (also "COBs" Chip On Board) comes, in which, for example, multiple LEDs on a PCB are mounted, whereby the required area of the LEDs can currently be reduced to about one-third. As a result, the solution according to the invention can be accommodated in a conventional luminaire housing, wherein the surface not required can be replaced by the cooling module. In this way, according to the invention, the heat radiation and the light are brought in the same direction, whereby the thermodynamic problems are solved much better.

The invention takes account of the fact that thermal energy always flows from bodies of higher temperature in the direction of bodies with lower temperature, that is, the second law of thermodynamics.

Following this principle, the ways are shown how the heat on those surfaces of the lamp or the light source, which are directed in the direction of the light, and / or diverted.

It is also important and advantageous in connection with the invention for the projections to be tightly attached so that the curves on the base of adjacent projections merge into one another. This means that the axes of adjacent protrusions have a spacing which corresponds to approximately twice to three times the average diameter of the protrusions. Especially - - Has it turned out to be advantageous if the projections on the body are mounted on the gap. d .h. when the rows are offset from one another.

For technical reasons, there are different starting solutions that can be used alternatively or cumulatively:

Luminaires whose light sources distribute the light via lenses;

Luminaires whose light sources transmit the light without additional lenses (except those directly connected to the LEDs);

Luminaires whose light sources are transmitted via direct reflectors, the light source and the reflector being aligned in the same direction;

Luminaires whose light sources are transmitted via indirect reflectors, the light source and the reflector being oriented in the opposite direction;

Luminaire units with electronic modules which have all components (eg PCB, LEDs, Driver Remote / Radio Unit, etc.) integrated in one housing.

Luminaire units with electronic modules, which on the one hand have integrated the lighting components and on the other hand the electronic modules for information processing in two separate housings.

The light sources (LEDs, OLEDs o. The like.) Are installed according to a preferred embodiment in a box (LED module) according to the respective legal requirements, the housing consists of very good heat conducting material, such as aluminum alloys. A vandal-resistant glass cover may be used to protect the underlying lenses. This element / module is the actual light source.

The area on the underside of the luminaire, where the cooling module is located, assumes the function of accommodating the cooling module and illuminants.

Another particularly preferred variant of the invention provides that the main body of the cooling module has a recess into which the LED module for the light-emitting diode is inserted. Thereby, a simple production and an optimal thermal connection can be combined. - -

It is favorable if the base body of the cooling module is flat at least in the region of the LED module and both the emission direction and longitudinal axes of the cooling structures are perpendicular to the plane of the main body of the cooling module in this area. As a result, particularly favorable flow conditions can be achieved.

It is preferably provided that the cooling structures at the base have a larger cross-section than in the region of their tip and preferably taper continuously from the base to the tip. As a result, a larger cross section is available to the heat flow at the base of the cooling structures, which favors the heat dissipation, and moreover, the Wantflächen the cooling structures are inclined so that a larger proportion of radiated heat no longer impinges on other parts of the surface of the cooling module.

An effective measure for improving the heat dissipation is also to provide that the cooling structures are attached to the body along freely curved curves. This means that the individual cooling structures are not linearly lined up along straight lines, but have a somewhat irregular arrangement. An air flow that flows through the recesses between the cooling structures will therefore always impinge on other cooling structures and be deflected, which improves the heat transfer accordingly.

A further improvement of the thermal effect of the invention can be achieved by the fact that heat-insulating layers, the alternative or additive, on the top or bottom of the interior of the luminaire housing, are introduced.

Subsequently, the present invention relates to a luminaire with a specific expression with a light module of the type described above. According to the invention, this luminaire is characterized in that the LED module is only partially connected to the luminaire housing.

Particularly preferably, a plurality of spaced-apart LED modules are provided. In this case, cooling structures are arranged in particular also in the interstices, so that a further lowering of the temperature can be achieved.

Particularly suitable for this purpose are LED modules with indirectly radiating reflectors, wherein the PCB emits the heat a priori in the direction of the light beam. The solution according to the invention provides the thermal connection of the PCB with the cooling structure. This increases the heat output efficiently. Analogously, a control and / or communication electronics in the housing - - Be provided, which also has a thermal connection with the cooling structure for the dissipation of heat.

Alternatively, a control and / or communication electronics may be provided in a separate housing, which is similar to the housing of the lamp described above, apart from the fact that there are no bulbs. This represents an advantageous alternative to the known arrangement of the electronics in the mast, which carries the lamp. The cooling takes place primarily via the downwardly projecting projections.

They show schematically:

1 shows a variant of an inventive lighting module in section along line I - I in Fig. 2.

FIG. 2 shows the lighting module FIG. 1 in a plan view; FIG.

3 shows a luminaire with a lighting module according to FIG. 1 and FIG. 2 in the

Cut;

Fig. 4a and Fig. 4b each show a detail of FIG. 1 in different embodiments;

Fig. 5a, Fig. 5b, FIG. 6a and FIG. 6b show further embodiments of luminaires or electronic modules according to the invention; and

Fig. 7 shows a detail of a preferred embodiment.

The light module of FIG. 1 consists of a cooling module 1, in which a flat LED module 2, namely a PCB, for several LEDs 3a, 3b, 3c, 3d is used. The LED module 2 is held in a recess 4 of the cooling module 1, so that the best possible heat transfer is ensured. The main emission direction of the LEDs 3a, 3b, 3c, 3d is indicated by 5.

The cooling module 1 consists of a base body 6, on which a plurality of projections 7 are attached. The projections 7 are used to increase the surface in order to best dissipate the heat generated by the LEDs 3a, 3b, 3c, 3d. The projections are according to the variant of FIG. 4a have a substantially conical shape and extend in a direction at right angles to the plane of the main body 6. They have a length I which, for example, corresponds to three times to ten times the value of the mean diameter d. - -

Alternatively, the protrusions are according to the variant of FIG. 4b also be formed spherical and have a length I, which corresponds approximately to the mean diameter d.

From Fig. 2, it can be seen that the individual projections 7 are not lined up linearly, but are arranged along freely curved lines 8 so as to produce increased turbulence in a flow in any direction.

In Fig. 3, a lamp is shown having a housing 10 having an opening 11 in which a cooling module 1 is inserted. Inside the housing 10, a first insulating layer 12 is provided to prevent unwanted heat input, for example by extreme sunlight. In addition or alternatively, a further insulating layer 13 is provided on the inside of the cooling module 1, which forces a radiation of the heat to the outside.

A driver circuit 14 is also attached to the cooling module 1 and is therefore also cooled. The driver circuit 14 is connected via a supply cable 15 to the LED module 2.

In Fig. 4a, a projection 7 is shown in detail. As stated above, the average diameter d, which is the diameter approximately in the middle of the longitudinal extension, is significantly smaller than the length I in the direction of the axis 7a, which is perpendicular to the plane 22 of the main body 6. In the region of the base 16, the cross section of the projection 7 is enlarged, and in the region of the tip 17, a smaller cross section is formed.

In Fig. 4b, an alternative projection 7 is shown in detail, which is formed squat. Here, the average diameter d, which is the diameter approximately in the middle of the longitudinal extent, is slightly larger than the length I in the direction of the axis 7a.

The lamp of Fig. 5a also has a housing 10 in which a cooling module 1 is used. In contrast to the embodiment variant described above, however, the LED module 2 with the LEDs 3a, 3b, 3c, 3d is aligned inwards, so that the light is reflected at a reflector 18 and emitted through a glass pane 19. The emission direction 20 is indicated by an arrow. It can be seen that in this embodiment as well, the projections 7 are aligned in the emission direction 20. With 21 individual rays are indicated, emanating from the LEDs 3a, 3b, 3c, 3d.

The LED module 2 is held at one end 2a in a recess of the cooling module, which is formed by a projection 22. This can be next to one - - Mechanically stable support and excellent heat transfer both from the bottom and from the top of the LED module 2 are guaranteed.

The lamp of Fig. 5b also has a housing 10 in which a cooling module 1 is inserted. In contrast to the embodiment variant described above, cooling structures are also arranged on the side surfaces of the luminaire

Luminaire of Fig. 6a is an extension of Fig. 3. This contains in addition to the lighting functions and electronics modules for information processing (23). The cooling structures can, as shown in FIG. 5b be pronounced

The electronic module of FIG. Fig. 6b is a modification of Fig. 6a. It contains only the electronics modules for information processing 23. The cooling structures according to the invention can be extended to up to five surfaces (without upper covering surface).

Fig. 7 shows schematically the close arrangement of the pins 7 on the gap, i. in each case offset by half a pitch rows.

Claims

PATENT APPLICATIONS

1. light module, comprising a cooling module (1), which consists of a base body (6) on which a plurality of cooling structures are formed, which are at least partially formed as projections (7), wherein the cooling module (1) provided a free surface of cooling structures is and at least one LED module (2) for at least one light emitting diode (3a, 3b, 3c, 3d) is mounted, and wherein the lighting module has a projection (7) approximately corresponding emission direction (5, 20), characterized in that the projections (7) are designed according to thermally optimized free-form surfaces.

2. Light module according to claim 1, characterized in that the projections (7) have a base body (6) rounded base (16).

3. Light module according to one of claims 1 or 2, characterized in that the main body of the cooling module (1) has at least one recess (4) into which the LED module (2) for the light emitting diode (3a, 3b, 3c, 3d ) is used.

4. Light module according to one of claims 1 to 3, characterized in that the base body (6) of the cooling module (1) at least in the region of the LED module (2) is flat and both the emission direction (5, 20) and longitudinal axes ( 7a) of the cooling structures are perpendicular to the plane (22) of the base body (6) of the cooling module (1) in this area.

5. Light module according to one of claims 1 to 4, characterized in that the projections (7) on the base (16) have a larger cross-section than in the region of its tip (17) and preferably from the base (16) to the top (17 ) are tapered.

6. Light module according to one of claims 1 to 5, characterized in that the projections (7) on the base body (6) are mounted on the gap.

7. Light module according to claim 6, characterized in that the projections (7) are mounted closely, so that the curves on the base (16) of adjacent projections (7) merge into one another.

8. Light module according to one of claims 1 to 7, characterized in that the cooling module (1) at its the radiation direction (5, 20) opposite side is formed predominantly flat.

9. Light module according to one of claims 1 to 8, characterized in that the cooling module (1) at its the radiation direction (5, 20) opposite side of a receptacle for the driver circuit (14) of the light-emitting diodes (3a, 3b, 3c, 3d) having.

10. Light module according to one of claims 1 to 9, characterized in that the projections (7) are formed crowned.

11. Light module according to one of claims 1 to 10, characterized in that the cooling structures (7) have a substantially circular cross-section.

12. Light module according to one of claims 1 to 11, characterized in that a module (23) is provided for information processing.

13 light module according to one of claims 1 to 12, characterized in that the projections (7) from the base body (6) substantially parallel to the emission direction (5) of the light-emitting diodes (3a, 3b, 3c, 3d) protrude.

14. luminaire having a housing and having a cooling module (1) inserted in an opening (11) of the housing, the at least one LED module (2) for at least one light-emitting diode (3a, 3b, 3c, 3d), wherein the cooling module ( 1) consists of a base body (6) on which a plurality of cooling structures formed as projections (7) are formed, wherein the lamp has a radiation direction (20) which is oriented in a direction in which project the projections (7), characterized in that the projections (7) are designed correspondingly thermally optimized free-form surfaces.

15. Luminaire according to claim 14, characterized in that the main body of the cooling module (1) has at least one recess into which the LED module for the light emitting diode (3a, 3b, 3c, 3d) is inserted.

16. Luminaire according to one of claims 14 or 15, characterized in that the emission direction of the lamp (20) with the emission direction (5) of the LED module (2) coincides and that the projections (7) from the opening (11) protrude ,

17. Luminaire according to one of claims 14 or 15, characterized in that in the lamp, a reflector (18) is provided and that the emission direction (5) of the LED module (2) in the interior of the lamp to the reflector (18) is oriented ,

18. Light according to one of claims 14 to 17, characterized in that the housing (10) at the opening (11) opposite side is thermally insulated.

19. Luminaire according to claim 18, characterized in that the housing (10) has thermally insulated surfaces on the inside of the opening (11).

20. Luminaire according to one of claims 14 to 19, characterized in that a plurality of spaced-apart LED modules (2) are provided.

21. Light according to one of claims 14 to 20, characterized in that the LED module (2) is only partially connected to the light housing.

22. Luminaire according to one of claims 14 to 21, characterized in that a module (23) for information processing with the cooling module (1) is connected.

23. Luminaire according to one of claims 14 to 21, characterized in that a module (23) is provided for information processing in a separate housing, which has analogous to the housing of the lamp projections (7), of the main body (6) substantially protrude down and the corresponding thermally optimized free-form surfaces are formed.

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