DE102009054474A1 - Light module and light chain - Google Patents

Abstract

The light module has a substrate (2) which is equipped on its front side (3) with at least one light source (4), in particular light emitting diode, wherein the substrate (2) laterally (5) and on the front side (3) of a first potting compound (6) is at least partially covered, and wherein a respective light exit surface (7) of the at least one light source (4) and at least partially a back (8) of the substrate (2) are free from the first potting compound (6). The luminous chain (31) has a plurality of lighting modules (1), adjacent lighting modules (1) being connected to one another by means of at least one electrical connecting line (32), wherein ends (33) of the electrical connecting line (32) attached to the adjacent lighting modules (1) are shed by means of the respective first potting compound (6).

Description

The invention relates to a lighting module, comprising a substrate which is equipped on its front side with at least one light source, in particular light emitting diode. The invention further relates to a luminous chain with a plurality of interconnected lighting modules.

So far, such lighting modules have been protected by painting their boards, by enclosing the boards in a closed housing or by a complete encapsulation of the board. However, these known measures either only a little protection against a particular mechanical but also chemical stress and / or a bad thermal contact, which greatly hinders a heat dissipation from the LED module for cooling the light sources.

It is the object of the present invention to provide a robust, protected lighting module, which allows a good thermal connection to the environment.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims.

The object is achieved by a light module, comprising a substrate which is equipped on its front side with at least one light source, in particular light emitting diode, wherein the substrate is at least partially covered laterally and at the front by a first potting compound, and wherein a respective light exit surface of at least one light source and at least partially also a back side of the substrate are free of the first potting compound.

Due to the presence of the first potting compound, which acts as a protective sheath, the luminescent module can be protected from mechanical damage from the side and from the front. The first potting compound can be selected in particular to a mechanical stress and does not need to be translucent. The protective jacket can also protect against moisture and / or chemical stress. The so equipped lighting module is correspondingly robust. The fact that the light exit surface is not covered by the first potting compound, light can escape unhindered. The fact that the back of the substrate is at least partially free of the typically heat-damping first potting compound, in other words is not completely covered by this, causes that there generated by the light sources and propagating through the substrate heat can be easily and effectively derived, which in turn allows an effective thermal connection.

The at least one light source may in particular comprise at least one light-emitting diode. Light-emitting diodes have a low overall height and are mechanically relatively insensitive. The light-emitting module is particularly preferred for light-emitting diodes with a power of more than 0.5 watts, since their heat loss, if not dissipated, the life and reliability of the light-emitting diodes sensitive shortened.

The substrate may be equipped at the front except with the at least one light source with electronic components as with at least one circuit, for. As a driver module, capacitors, resistors, etc. These electronic components can be covered depending on the design of the first potting or free of it.

Also, at least one electrical line, for. As connection cable, be attached, which may be covered for a secure connection in particular of the first potting compound.

The first potting compound may consist in particular of hotmelt, also known as hotmelt adhesives, hotmelt adhesives or hot melt adhesives.

The first potting compound may be provided with colored fillers in order to be able to adjust the color of the light module. In particular, the achromatic potting colors white, gray and black are preferred. But there are also colorful colors possible.

It is an embodiment that the substrate is substantially completely covered on the side and on the front side by a first potting compound, and the back side of the substrate is substantially free of the first potting compound. As a result, the protection of the light module directed laterally and forwards or toward the front side is combined with an enlargement of the rear side optimized for a good thermal connection.

It is a particular embodiment that the back of the substrate is flush with the first potting compound or protrudes rearwardly over the first potting compound. Thus, a simple and thermally effective surface mounting of the light module on the back of the substrate is possible, for. B. on a heat sink.

It is still an embodiment that the substrate has at least one laterally protruding projection, which is surrounded by the first potting compound. So can a form-fitting Connection of the first potting compound to the substrate can be achieved.

It is yet another embodiment that the substrate has at least one laterally introduced recess and / or at least one passage from the front to the back, which are at least partially filled in front of the first potting compound. Even so, a positive connection of the first potting compound to the substrate can be achieved.

It is also an embodiment that the substrate is designed as a circuit board, in particular as a metal core board or a ceramic board. These two types of boards have the advantage that they can derive the heat generated by the at least one light source particularly effectively to their back. This allows a particularly good cooling of the at least one light source.

It is a further development for increasing robustness that the metal-core board has a non-rusting metal, in particular aluminum.

It is still an embodiment that a wall thickness of the first potting compound is at least 1 mm. This wall thickness ensures high impact and abrasion resistance.

It is further an embodiment that the respective light exit surface of the at least one light source is surmounted by the first potting compound surrounding it. Thus, the at least one light source is also largely protected against mechanical stress, in particular abrasion.

It is furthermore an embodiment that the respective light exit surface of the at least one light source is covered by a translucent second potting compound. Thus, the at least one light source is also largely protected against mechanical stress, in particular abrasion. The translucent second potting compound may be transparent or translucent (opaque). The translucent second potting compound may, for. B. from a low pressure injection molding material, for. As silicone or hotmelt exist.

In general, the first potting compound and the second potting compound can also be identical, and thus the luminescent module can be surrounded by, or potted from, a uniform, light-permeable potting compound, with the exception of at least one part of the back side of the substrate. The non-cast surface of the back of the substrate can then z. B. be connected to a heat sink or his. The heat sink may be at least partially encapsulated.

It is still an embodiment that the first potting compound is bevelled to the respective light exit surface. This allows a wide light beam angle can be maintained.

It is also a development that the back of the substrate and / or the light module is at least partially covered by a protective lacquer, for. B. to protect against corrosion or a slight mechanical stress.

In addition, it is a further development that the lighting module, in particular the substrate, has at least one bore for receiving a screw in order to fasten the lighting module in a screwing manner.

It is also advantageous for a simple attachment development that the back of the light module at least partially has at least one adhesive element, for example, a double-sided adhesive tape.

It is for an effective heat dissipation from the light module, in particular without a connection to an additional heat sink, advantageous embodiment that the back of the substrate has a heat sink structure, for. B. at least one cooling fin, cooling pin and / or lamella. As a result, in other words, a heat sink is integrated into the substrate. The heat sink may be cast at least partially, in particular at the edge, together with the substrate. The cooling structure (s) of the heat sink (ribs, fins, pins, etc.) can protrude in particular via the potting compound.

It is an alternative or additional embodiment for effective heat removal that a heat sink is attached to the rear side of the substrate or the light module.

The object is also achieved by a luminous chain, comprising a plurality of lighting modules according to one of the preceding claims, wherein adjacent lighting modules are connected to each other by means of at least one electrical connection line, wherein attached to the adjacent lighting modules ends of the electrical connection line are shed by means of the respective first potting compound.

An intermediate section between the potted ends may in particular be free of the first potting compound or may not be potted. The casting of the ends of the at least one electrical connection line protects against damage to the contact between the at least one electrical connection line and the Substrate and also fixes the two elements against each other.

For achieving a flexible luminous chain for laying even on curved surfaces and / or in lateral curves, it is a development that the at least one electrical connection line is flexible.

• – Bestücken der Leiterplatte eines jeweiligen Leuchtmoduls mit der mindestens einen Leuchtdiode und ggf. mindestens einem elektronischen Bauelement;
• – Befestigen, z. B. Anlöten, der mindestens einen elektrischen Leitung, z. B. Kabelverbindung; für eine Leuchtkette insbesondere zum Verbinden einzelner Leuchtmodule zu der Leuchtkette;
• – Einlegen der bestückten und, bei einer Leuchtkette, verbundenen Platine in eine Gussform, z. B. durch ein Ansaugen auf der Unterseite mittels eines Vakuums;
• – Schließen der Gussform und Vergießen mit einer ersten Vergussmasse, z. B. mittels eines Spritzgussablaufs; und
• – Öffnen der Gussform und herausnehmen des Leuchtmoduls bzw. Leuchtkette.

The light module and / or the light chain can, for. B. be prepared with the following steps:

• - Equipping the circuit board of a respective light module with the at least one light emitting diode and optionally at least one electronic component;
• - Attach, z. B. soldering, the at least one electrical line, z. B. cable connection; for a light chain, in particular for connecting individual light modules to the light chain;
• - Inserting the assembled and, in a light chain, connected board in a mold, z. B. by suction on the bottom by means of a vacuum;
• - Closing the mold and casting with a first potting compound, z. B. by means of an injection molding process; and
• - Opening the mold and remove the light module or light chain.

In the following figures, the invention will be described schematically with reference to exemplary embodiments. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

1 shows a sectional side view of a potted LED module according to a first embodiment;

2 shows a section of a potted LED module according to a second embodiment;

3 shows a sectional side view of a potted LED module according to a third embodiment; and

4 shows a sectional side view of a luminous chain with a plurality of LED modules according to the first embodiment.

1 shows a sectional view in side view of an LED module 1 according to a first embodiment. The LED module has a substrate in the form of a metal core board 2 on, at the front 3 Light sources in the form of light-emitting diodes 4 are mounted. The side or side wall 5 and the front 3 the metal core board 2 are with a first potting compound 6 covered or potted, with both top light exit surfaces 7 the light-emitting diodes 4 as well as a back 8th the metal core board 2 not potted or from the first potting compound 6 are covered. The page 5 has a projection in the form of a circumferential chamfer 9 or a circumferential recess in the form of a corresponding recess 10 on. As a result, the first potting compound is form-fitting with the metal core board 2 and can not get away from it.

The LED module shown 1 is through the first potting compound 6 Protected laterally and from the front against mechanical as well as chemical stress. The backside 8th the metal core board 2 is not protected, with the back 8th typically for mounting the LED module 1 is used and is therefore exposed to only low mechanical loads.

For a sufficiently wide light cone, the surface of the first potting compound falls 6 at the front of the LED module 1 to the light exit surfaces 7 towards frusto-conical or truncated pyramid obliquely. The maximum height of the first potting compound 6 is at the front 3 the metal core board 2 thus higher than the height of the LEDs 4 , causing the light-emitting diodes 4 are protected in particular from a laterally directed or large area applied from the front mechanical stress.

Over the big back 8th can be one of the light emitting diodes 4 generated and through the metal core board 2 spread heat dissipated effectively. The metal core board 2 allows a particularly good heat spreading. The LED module 1 For a particularly effective dissipation of heat loss with its back 8th be attached to a heat sink, z. B. on a heat sink or a metallic carrier.

For clarity, electrical cables, z. As connecting lines, and electronic components not shown, but may be present and in particular by the first potting compound 6 to be shed with.

2 shows a sectional view in side view of a section of a potted LED module 11 according to a second embodiment. In contrast to the LED module 1 and additionally or alternatively to the chamfer 9 or the return 10 has the metal core board 12 a vertical passage 13 from the front 3 to the back 8th on, which is widened in the area of the back and with the first potting compound 6 is filled. Even so, a firm, positive connection of the first potting compound 6 with the metal core board 2 achieved or strengthened.

3 shows a sectional view in side view of a potted LED module 21 according to a third embodiment. In contrast to the LED module 1 stands the metal core board 22 now back over the first potting compound 6 out. In the protruding area 23 is the metal core board 22 as an integrated heat sink structure with multiple cooling pins 24 designed. This improves heat dissipation. The backside 8th the metal core board 2 , which in particular through the ends of the cooling pins 24 is formed, can continue to attach the LED module 21 be used.

In addition, the light exit surfaces 7 the light-emitting diodes 4 now by a translucent (transparent or translucent) second potting compound 35 covered, allowing direct protection of the light exit surfaces 7 results.

4 shows a sectional view in side view of a section of a light chain in the form of an LED chain 31 with example two LED modules 1 according to the first embodiment. Now also the electrical connection cables 32 between the adjacent LED modules 1 located. The ends 33 the connection line 32 Contact the respective metal core board 2 and are in the first potting compound 6 shed, making them mechanically safe on the LED module 1 are attached. A middle section 34 between the LED modules 1 is free of the first potting compound and thus flexible, which makes the LED modules 1 the LED chain 31 are flexibly positionable.

Of course, the present invention is not limited to the embodiments shown.

Thus, the first potting compound can also protrude over the board. The back side of the board can then be fastened, for example, to an upstanding base of a heat sink or carrier, or a heat sink can be mounted immersed in the recess of the first potting compound on the board.

Also, instead of a metal core board in particular another good heat-conducting substrate can be used, for. B. a ceramic substrate. In general, the type of board is not limited and may, for. B. also include other types of boards, z. B. type FR4.

LIST OF REFERENCE NUMBERS

1

LED module

2

Metal core board

3

Front of the metal core board

4

led

5

Side wall

6

first potting compound

7

Light-emitting surface

8th

Rear of the metal core board

9

circumferential chamfer

10

return

11

LED module

12

Metal core board

13

execution

21

LED module

22

Metal core board

23

projecting area

24

cooling pin

31

LED chain

32

interconnectors

33

End of the connection line

34

middle section

35

second potting compound

Claims (11)

Light module ( 1 ; 11 ; 21 ), - comprising a substrate ( 2 ; 12 ; 22 ), on its front side ( 3 ) with at least one light source ( 4 ), in particular light emitting diode, is equipped, - wherein the substrate ( 2 ; 12 ; 22 ) laterally ( 5 ) and at the front ( 3 ) of a first potting compound ( 6 ) is at least partially covered, - wherein a respective light exit surface ( 7 ) of the at least one light source ( 4 ) and at least partially a back ( 8th ) of the substrate ( 2 ; 12 ; 22 ) free of the first potting compound ( 6 ) are. Light module ( 1 ; 11 ; 21 ) according to claim 1, characterized in that the substrate ( 2 ; 12 ; 22 ) laterally ( 5 ) and at the front ( 3 ) of the first potting compound ( 6 ) is substantially completely covered and the back ( 8th ) of the substrate ( 2 ; 12 ; 22 ) substantially free of the first potting compound ( 6 ). Light module ( 1 ; 11 ; 21 ) according to claim 2, characterized in that the rear side ( 8th ) of the substrate ( 2 ; 12 ; 22 ) flush with the first potting compound ( 6 ) or at the rear over the first potting compound ( 6 ) stands out. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, characterized in that the substrate ( 2 ; 12 ; 22 ) at least one laterally projecting projection ( 9 ), which of the first potting compound ( 6 ) is surrounded. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, characterized in that the substrate ( 2 ; 12 ; 22 ) at least one laterally introduced recess ( 10 ) and / or at least one implementation ( 13 ) from the front ( 3 ) to the back ( 8th ), which before the first potting compound ( 6 ) are at least partially filled. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, in which the substrate ( 2 ; 12 ; 22 ) is configured as a metal core board or a ceramic board. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, in which a wall thickness of the first potting compound ( 6 ) is at least 1 mm. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, in which the respective light exit surface ( 7 ) of the at least one light source ( 4 ) of the surrounding first potting compound ( 6 ) is surpassed. Light module ( 1 ; 11 ; 21 ) according to claim 8, wherein the first potting compound ( 6 ) to the respective light exit surface ( 7 ) Beveled. Light module ( 1 ; 11 ; 21 ) according to one of the preceding claims, in which the respective light exit surface ( 7 ) of the at least one light source ( 4 ) of a translucent second potting compound ( 35 ) is covered. Luminous chain ( 31 ), comprising a plurality of lighting modules ( 1 ; 11 ; 21 ) according to any one of the preceding claims, wherein adjacent lighting modules ( 1 ; 11 ; 21 ) by means of at least one electrical connection line ( 32 ) are connected to each other, wherein at the adjacent lighting modules ( 1 ; 11 ; 21 ) attached ends ( 33 ) of the respective electrical connection line ( 32 ) by means of the respective first potting compound ( 6 ) are shed.

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