EP1923626A1 - LED module with integrated control - Google Patents

Abstract

The module (1) has a set of LED-components (6) and an electrical connection unit (13) that connects the LED-components with a current supply of a light assembly. Thermal contact units (2, 5) discharge heat loss of the LED-components to the light assembly. A control unit is integrated into the LED-module for controlling the LED-components. The control unit exhibits a drive circuit for controlling the LED-components individually or in group. Optical units e.g. plastic optic, are fitted into the housing. An independent claim is also included for a light assembly with a set of LED-components and a cooling body.

Description

State of the art

The present invention relates to an LED module, which is intended for installation in a lighting unit, wherein the LED module, a plurality of LED components, electrical connection means, via which the LED components can be connected to a power supply of the lighting unit, and at least one heat-conducting with the LED components connected thermal contact element, via which the heat loss of the LED components can be dissipated to the lighting unit or to a heat sink of the lighting unit comprises.

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

Not only in motor vehicles, LEDs are increasingly being used because they have some significant advantages over conventional light bulbs. LEDs have a longer life, a smaller size and a better efficiency in the conversion of electrical energy into light. Furthermore, LEDs are characterized by a Insensitivity to shocks and shocks, which is a significant advantage, especially in motor vehicles.

Despite the lower heat dissipation compared to incandescent lamps, the waste heat that occurs as a loss has to be dissipated against the backdrop of constantly increasing performance, even in LEDs, in order to prevent overheating and thus functional impairment or even destruction of the LEDs. Usually, the waste heat is dissipated from the underside of the LED components via their electrical connections and / or via a serving as a heat connection third contact to a metallic heat sink.

From the DE 195 28 459 C2 is a lighting unit is known in which a printed circuit board with a plurality of encapsulated LEDs in wired version is equipped. In order to dissipate the waste heat, a cooling plate provided with holes is arranged on the side of the printed circuit board equipped with the LEDs such that the heads of the LEDs project separately into the bores of the cooling plate and are individually aligned therein.

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 the desired application for the desired three-dimensional shape and be provided on the side facing away 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.

Therefore, increasingly prefabricated LED lighting modules (also called LED modules) are used in which a certain number of LEDs are combined in a particular arrangement into a module to achieve the required amount of light for certain applications. Such modules can be relatively easy to mount in a lighting unit. The control of the LED modules or the individual LEDs by means of special driver circuits, which is arranged as an external control unit outside the respective modules and to be mounted separately.

From the US 2006/0007013 A1 is an aircraft anti-collision warning light known, which also works with LEDs as a light source. Again, an electrical monitoring system may be provided in addition, by which the LEDs can be monitored for proper operation. In particular, monitoring circuits for a plurality of LED arrays may also be combined in a common monitoring unit.

Disclosure of the invention

Object of the present invention is to provide an improved LED module of the type mentioned, which allows an even easier and faster installation in a lighting unit.

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

The idea underlying the present invention is that a control unit for controlling the LED components is combined with the other components of the LED module to form a unitary assembly by integrating the control unit into the LED module. In particular, the control unit may comprise an electronic circuit designed as an integrated circuit (IC).

In this way, a prefabricated, compact and easy-to-install LED assembly is created, which already contains in addition to the LEDs, the electrical connection means and the thermal contact element for driving the LED module or the required for driving the LEDs elements. The previous separation of lighting part and control part thus eliminated.

The LED module according to the invention according to claim 1, over the prior art embodiments has the particular advantage that a separate assembly and subsequent connection of an external control unit for the LED module is no longer required, which the effort and thus the production costs of such LED modules equipped lighting unit significantly reduced.

The LED module may comprise both a plurality of individual LED chips and - alternatively or additionally - one or more structured substrates with embedded, in particular soldered, LED chips.

Advantageous developments and improvements of the LED module according to the invention will become apparent from the dependent claims.

For example, it is particularly advantageous if the control unit comprises at least one driver circuit, by means of which the LED components can be controlled individually or in groups.

It is furthermore particularly advantageous if the control unit comprises at least one multi-channel drive circuit, by means of which RGB LEDs can also be activated. The use of a multi-channel drive IC thus allows flexible use of the LED modules according to the invention also in lighting units for those areas in which it depends on multi-colored light signals.

According to a particularly preferred embodiment of the invention it is provided that the thermal contact element is formed by an open or closed housing made of a thermally conductive material, in which the LED components, the electrical connection means, the control unit and possibly provided further components of the LED module are. As a result, a robust and particularly compact design of the LED module is achieved, which is not only easy to handle, but at the same time also allows a particularly effective transition of dissipated heat. Thus, with a suitable attachment of the module in a thermally conductive recording of the lighting unit, especially directly in the heat sink of the lighting unit, the heat can be dissipated through the surface of the entire module housing. The housing can be any shape Having outer contour, which can be adapted to the requirements placed on the lighting unit. Preferably, the housing consists of a good heat-conducting material, in particular copper or aluminum.

It is particularly advantageous if in or on the housing, a disc-shaped base is provided from a good heat-conducting material on which the LED components are added. The waste heat can then be dissipated via the base, which is preferably adapted specifically to the number and size of the male LEDs of the module, depending on the type of module recording either directly or indirectly via the housing further to the lighting unit. In this case, the control unit can be mounted either on the same side of the base as the LEDs or the base is provided with electrical feedthroughs and formed so that the control unit is arranged on the opposite side of the LEDs back of the base. The base is in particular made in one piece with the housing and therefore also preferably consists of copper or aluminum.

It may also be favorable for a desired light output if optical means, in particular plastic optics or optical conversion means, for example an optical filling medium for color conversion of the light emitted by the LEDs of the module, are accommodated or fitted in the housing. Preferably, a housing which is open towards an end side can thus also be terminated by a suitably designed primary optics in order to achieve a specific focusing. In a particularly simple way, a plastic look can be used by clip-mounting in the housing.

A particularly easy assembly results when the LED components are first preassembled on a carrier board and then introduced into the LED module. It is advantageous here to arrange a drive circuit on the carrier board, as this can be dispensed with an external drive circuit for the LED components themselves. As a result, the steps for producing a corresponding LED module can be reduced since the light-generating LED components and the control can be applied in one operation.

In order to ensure a permanently effective heat transfer, it is further proposed that the outer sides of the housing at least partially have a toothing or knurling. About such a toothed or knurled housing contour, the housing of the LED module can be pressed particularly good thermal conductivity in a heat sink of the lighting unit.

The subject matter of the present invention is furthermore a lighting unit with a plurality of LED components and a heat sink, via which the heat loss of the LEDs can be dissipated, wherein the lighting unit comprises one or more LED modules of the type described above. Such a lighting unit is due to the prefabricated LED modules with integrated control unit particularly fast and easy to assemble, allowing a cost-effective production.

It is particularly advantageous if the one or more LED modules each have a housing of the aforementioned type, which is received positively in the heat sink of the lighting unit. As a result, not only a very quick and easy installation is made possible with a relatively simple and robust construction, but it is mainly limited to a required alignment of the LED components adjustment to a minimum or even made completely unnecessary. Advantageously, the housings of the prefabricated LED modules are directly accommodated in the frictional insertion into the heat sink in such a way that the desired focusing of the light-emitting diodes is obtained virtually automatically in a particularly fast and simple manner. At the same time, a fast and particularly effective heat distribution (heat spreader function) is made possible in this way.

A particularly precise alignment of the LED module can be achieved in that the housing is inserted into an opening or in a recess of the heat sink of the lighting unit, preferably pressed. The pressing of the module housing in a complementary recording of the heat sink allows a particularly fast, positive and positive recording and alignment of the LED module. Advantageously, a plurality of housing of a plurality of LED modules can be pressed into a common heat sink, whereby particularly close tolerances of the individual LED modules can be maintained and a complex optical alignment of the LED modules to each other during assembly is no longer necessary. In the production of such a lighting unit, it is particularly advantageous for achieving a highly accurate optical alignment when multiple openings and / or wells are simultaneously and / or introduced in a single clamping of the heat sink in the heat sink for receiving a plurality of LED modules, which advantageously with corresponding machining centers can be executed.

Regardless of optical applications and lighting units are for example from the DE 197 57 513 A1 Einpressdioden known in cooling plate design, which are received positively in a recess or depression of a cooling plate. Such press-in diodes are used, for example in welding equipment as a rectifier, where it does not depend on an exact alignment during assembly.

It is also advantageous to carry out the heat sink as a metallic carrier strip, a so-called lead frame. Such lead frames are already known for cooling power semiconductors and can therefore be manufactured and installed inexpensively. They provide a sufficiently good heat sink for the LED and its control. The fact that on the lead frame one-sided assembly can take place, the manufacturing processes for the production of a lighting unit with LED modules are simplified. The lead frame made of copper is particularly advantageous in this case since copper can dissipate the heat which is produced when generating light particularly well.

It is particularly advantageous if the lighting unit according to the invention is a headlamp, in particular a motor vehicle headlamp, comprising a headlamp heat sink in which at least one module housing of the type described above is positively received, preferably pressed in or screwed in. The present invention can thus be used advantageously in particular in the automotive sector, but also in general lighting applications.

Brief description of the drawings

• Figur 1: dreidimensionale Darstellung eines erfindungsgemäßen LED-Moduls von der Vorderseite;
• Figur 2: Darstellung des LED-Moduls aus Figur 1 von der Rückseite;
• Figur 3: Darstellung des LED-Moduls aus Figur 2 mit abgenommener Steuereinheit;
• Figur 4: Schnittdarstellung des LED-Moduls aus Figur 1;
• Figur 5: dreidimensionale Darstellung einer zweiten Ausführungsform eines erfindungsgemäßen LED-Moduls; und
• Figur 6: dreidimensionale Darstellung eines Kühlkörpers eines Leuchtaggregats mit drei LED-Modulen nach Figur 5.
• Figur 7 zeigt ein Ausführungsbeispiel für einen metallischen Trägerstreifen als einen Kühlkörper für ein erfindungsgemäßes Leuchtaggregat mit mehreren LED-Modulen.

In the drawings, embodiments of the invention are shown, which are explained in more detail in the following description.
Show it:

• Figure 1: three-dimensional view of an LED module according to the invention from the front;
• Figure 2: representation of the LED module of Figure 1 from the back;
• FIG. 3: illustration of the LED module from FIG. 2 with the control unit removed;
• Figure 4: sectional view of the LED module of Figure 1;
• FIG. 5 shows a three-dimensional illustration of a second embodiment of an LED module according to the invention; and
• 6 shows a three-dimensional view of a heat sink of a lighting unit with three LED modules according to FIG. 5.
• Figure 7 shows an embodiment of a metallic carrier strip as a heat sink for a lighting unit according to the invention with a plurality of LED modules.

Embodiments of the invention

The LED module 1 shown in Figures 1 to 4 is intended for installation in a not shown in the figures lighting unit. It comprises a cylindrical housing 2 made of aluminum, which in each case has a recess 3 at its two end faces and is thus designed to be open. Between the two recesses 3 is a disc-shaped base 4, which is integrally connected to the sleeve-shaped wall 5 of the housing 2.

In the front recess 3 a total of four LED components 6 are added, which are each designed here as a surface-mounted LED chips. The individual LED chips 6 are arranged in a 2x2 array on a carrier board 7, which is mounted directly on the base 4. In this way, the LED chips 6 are thermally conductive connected via the carrier board 7 and the base 4 with the wall 5 of the module housing 2. The module housing 2 in this case represents a thermal contact element, via which the heat loss of the LED components 6 can be dissipated to the LED module 1 receiving luminous unit or to a heat sink 8 of a lighting unit.

In the second recess 3 of the module housing 2, a circuit board 9 is accommodated, which forms a control unit 10 for the LED chips 6 with a drive circuit applied thereto. The control unit 10 is connected to the LED chips 6 via two contact pins 11 that are led through the base 4 in an insulating manner. For this purpose, the front end surfaces of the contact pins 11 are connected by bonding wires 12 to the carrier board 7 and with the LED chips 6 mounted thereon. The rear end regions of the contact pins 11 each contact a connection socket of the control unit 10 embedded in the printed circuit board 9.

The rear side of the circuit board 9 is connected to a connecting cable 13 designed here as a flat cable, via whose lines, on the one hand, the LED chips 6 can be supplied with power and, on the other hand, external control signals can also be supplied to the control unit 10. Instead of a cable, other connection means 13 may be provided, such as connector or pins.

To complete the front side of the LED module 1, a plastic primary optics 14 can be glued over the LED chips 6 and / or inserted into the corresponding recess 3, in particular clipped, as shown in Figure 5. In the LED module 1 shown here, the four LED chips 6 are arranged in a row next to one another on the carrier board 7. Basically, any number of LED chips 6 can be provided in any arrangement in the LED module 1, depending on the purpose. Also, the back of the housing 2 can be completed by a suitable cover.

In any case, a pre-assembled LED module 1 is obtained, in which a control unit 10 for driving the LED components 6 is already integrated. Of course, the control unit can also be arranged at other locations of the LED module 1, for example on the rear side and / or the front side of the carrier board 7 of the LED chips 6. The pre-assembled LED modules1 are later particularly quickly and easily inserted into suitable recesses 15 of a heat sink 8 of a lighting unit.

In a first embodiment, the LED chips 6 can be soldered onto a carrier board 7 in the form of a driving silicon IC. Thus, in this embodiment, the drive itself serves as a carrier for the LED chips. In a further embodiment, the integrated control can also be carried out in silicon carbide, which is characterized by good thermal properties. Such an integration would be particularly advantageous because some LED manufacturers silicon carbide is used as a substrate for the LEDs. The monolithic semiconductor lighting unit can be equipped by this chip-on-chip solution directly with an example. Phosphorus-active lighting part and an integrated control part, in which a drive by integrated circuits, sensors and / or other switching logic is already integrated. Due to the one-sided chip mounting on the diode socket or a lead frame, the number of steps required to produce an LED module can be reduced. In addition, by means of an integrated drive, for example in the form of an ASIC, a plurality of possibly different LED chips can also be arranged on a carrier and driven at the same time.

In order to ensure a particularly effective release of the heat loss to the heat sink 2, the LED modules 1 preferably have on their housing 2 an outside knurling 16, via which they are positively and non-positively pressed into the recesses 15 of the heat sink 8. At the same time a particularly simple, yet highly accurate optical alignment of the individual LED modules 1 to each other is achieved, so that a subsequent adjustment of individual LEDs for the desired focusing of the lighting unit during assembly is not required. The LED modules 1 can be pressed directly into their predetermined by the recesses 15 positionally accurate alignment in the heat sink 8.

The heat sink 8 shown in FIG. 6 has three recesses 15 in order to be able to record a total of three prefabricated LED modules 1 according to the invention, each with an integrated control unit. In order to achieve a particularly effective cooling of the heat sink 8, which also consists of aluminum, provided with cooling fins 17, via which the waste heat can be dissipated to the environment. Since the heat sink 8 is made of aluminum here as well as the housing 2 of the LED modules 1, not only results in a particularly good heat transfer due to the identical thermal expansion coefficient, but it is also a permanently secure interference fit between the module housings 2 and the heat sink 8 guaranteed ,

Again, the number and arrangement of the holes or recesses 15 as well as the shape of the heat sink 8 can be varied depending on the requirements of the associated lighting unit requirements. In particular, any orientation of the bores or recesses 15 in three-dimensional space is possible with a three-dimensional heat sink 8. In particular, the heat sink 8 may also be designed for a motor vehicle headlight.

In order to achieve a high-precision alignment of the LED modules 1 in the heat sink 8, the recesses 15 are preferably introduced in a corresponding processing center in only a single clamping.

FIG. 7 shows a metallic carrier strip, a so-called lead frame 20, to which a plurality of LED modules 1 can be attached. The carrier strip 20 is preferably made of copper or a copper alloy. The carrier strip 20 has a first mounting web 21 and a second mounting web 22, wherein the two mounting webs 21, 22 form parallel webs, in each of the mounting holes 23 are introduced. By means of the mounting openings 23, the carrier strip 20 can be mounted in a housing and optionally connected to further cooling elements. Support members 31, 32 and 33, which in the embodiment shown here form an approximate rectangular, planar surface, are held by thin support arms between the two webs 21, 22. On the flat surfaces of the support members 31, 32, 33 each mounting surfaces 41, 42, 43 are sketched, where the respective LED modules 1, for example by gluing or can be applied by soldering. The module housing 2 preferably contacts the surface of the respective associated carrier element. The mounting webs 21, 22 are each connected only via thin connecting webs with the carriers 31, 32, 33. In FIG. 7, for reasons of clarity of the drawing, only two connecting webs 51, 52 are provided with a reference numeral. By means of the openings formed by the thin design of the connecting webs 51, the carriers 31, 32 can be cooled with air guided past them. Furthermore, however, allow the connecting webs, in particular in an embodiment of a material with good heat conduction, that over the connecting webs 51, 52 heat to the mounting webs 21, 22 is led away for further dissipation. The attachment of the LED modules on the surface of the carrier 31, 32, 33 can be done by means known from the processing of power semiconductors manufacturing processes.

Claims (15)

LED module for installation in a lighting unit, wherein the LED module (1) a plurality of LED components (6), electrical connection means (13) via which the LED components (6) are connectable to a power supply of the lighting unit, and at least a thermal contact element (2, 5) via which the heat loss of the heat-conducting associated LED components (6) can be dissipated to the lighting unit,
characterized,
that a control unit (10) for driving the LED components (6) in the LED module (1) is integrated. LED module according to claim 1, characterized in that the control unit (10) comprises at least one driver circuit, by which the LED components (6) can be controlled individually or in groups. LED module according to claim 1 or 2, characterized
that the control unit (10) comprises at least one multichannel driver circuit are controlled by the RGB LED components (6). LED module according to one of the preceding claims, characterized in that the thermal contact element is formed by an open or closed housing (2) made of a thermally conductive material, in which the LED components (6), the electrical connection means (13) Control unit (10) and optionally provided further components of the LED module (1) are added. LED module according to claim 4, characterized in that the housing (2) comprises a disc-shaped base (4) made of a thermally conductive material, on which the LED components (6) and the control unit (10) on opposite sides or on a common side of the base (10) are added. LED module according to claim 4 or 5, characterized in that in the housing (2) optical means (14), in particular a plastic optics, are received or fitted. LED module according to one of claims 4 to 6, characterized in that the outer sides of the housing (2, 5) at least partially have a toothing or knurling (16). LED module according to one of the preceding claims, characterized in that the LED components (6) are arranged on a carrier board (7) in the LED module (1). LED module according to claim 8, characterized in that the carrier board (7) is designed as an integrated circuit, in particular as an ASIC. LED module according to one of claims 8-9, characterized in that a drive circuit for the LED components (6) is arranged on the carrier board (7). Illuminating unit with a plurality of LED components (6) and a heat sink (8, 20), via which the heat loss of the LED components (6) can be dissipated,
characterized in that it comprises at least one LED module (1) according to one of the preceding claims. Illuminating unit according to claim 11, characterized in that it is designed as a headlamp, in particular as a motor vehicle headlamp, which has a headlamp heat sink (8) in which at least one LED module (1) received, preferably by means of a module housing (2, 5) is pressed. Illuminating unit according to one of claims 11 to 12, characterized in that the cooling body (20) is designed as a metallic carrier strip (20). Illuminating unit according to claim 11 or 12, characterized in that the at least one LED module (1) comprises a housing (2, 5) according to one of claims 4 to 7, which is positively received in the heat sink (8). Illuminating unit according to claim 14, characterized in that the housing (2, 5) inserted into an opening or in a recess (15) of the heat sink (8), is preferably pressed.

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