EP1923627B1 - Integrated control of LED assemblies - 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 in particular for installation in a lighting unit. It comprises a plurality of LED components which are arranged on one or more carrier element (s). In addition, other elements, such as electrical connection means, via which the LED components can be connected to a power supply, and / or a thermally conductive connected to the LED components thermal contact element, via which the heat loss of the LED components preferably to the lighting unit or ., Can be dissipated to a heat sink of the lighting unit, be integrated into the LED module.

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. Preferably, these may be LED chips with phosphor coating or even RGB LEDs. 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 good efficiency in the conversion of electrical energy into light. Furthermore, LEDs are characterized by insensitivity to shocks and vibrations, which represents a considerable advantage, especially in motor vehicles.

From the DE 195 28 459 C2 a lighting unit is known in which a plurality of encapsulated LEDs are arranged in a wired version on one side of a support plate. The operating current is supplied to the LEDs via a circuit in the form of printed conductors, which are applied to the other side of the carrier plate. In addition, in order to dissipate the waste heat on the side of the carrier plate equipped with the LEDs, a cooling plate provided with bores is arranged such that the heads of the LEDs each protrude separately into the bores of the cooling plate.

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 specific arrangement to form a module to the required Amount of light for specific applications. Such modules can be mounted relatively easily 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 DE 101 29 691 A1 For example, a scanning head module with a photo-sensitive detector is known, such as can be used in scanners or copiers or fax machines. In this case, the photosensitive detector are integrated with a processor circuit in a module, so that a line for transmitting the detected photosignals between the processor circuit and the photosensitive detector is not needed.

From the US 2006/0012986 A1 a light-emitting diode array arrangement is known in which adjacent to the light emitting diodes an integrated circuit for driving and passive components are arranged on a printed circuit board, which has heat conduction properties.

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 on which the present invention is based is that a control unit for controlling the LED components is combined with the LED module to form a uniform assembly. For this purpose, a control unit is integrated into the LED module, which forms the carrier element at least for individual LED components fastened directly thereto.

In this way, a prefabricated, compact and easy-to-install LED assembly is created, which in addition to the LEDs also already contains the necessary for controlling the LED module or the control of the LEDs control 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. For processing the LED module according to the invention only a few steps are required.

According to the invention, the control unit comprises an electronic or integrated circuit which is designed as an IC (integrated circuit), in particular as an application-specific ASIC (ASIC), wherein the required functions for controlling the LEDs in the ASIC can be mapped with suitable processes.

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

Advantageously, the control unit can also comprise a silicon IC or a silicon carbide IC, wherein silicon carbide is characterized by very good thermal properties and is often used as a base material for LEDs.

The control unit also includes the logic to operate the LED module, thereby creating a fully functional LED unit. In this case, the control unit may comprise driver circuits, by which the LED components individually or in groups, in series or in parallel or in RGB arrangements can be controlled, which allows flexible use of the LED modules according to the invention also in areas where it arrives at multicolored light signals.

It is also particularly advantageous if sensor means for monitoring the function of the LED components and / or compensating means to compensate for aging of the LED components are integrated into the control unit. These monitoring functions can be mapped in particular in an ASIC.

In accordance with a particularly preferred embodiment of the invention, in particular with regard to ease of manufacture, it is provided that the LED components are glued or soldered to the control unit, in particular to the IC. For this purpose, in the design of an IC, the area required for the subsequent LED assembly is omitted, which may include the contact area for the individual LED components and the areas required for the electrical connections, for example so-called bondpads. Preferably, these surfaces can be coated with a suitable metal coating. The LED module can advantageously form a monolithic chip-on-chip unit.

According to the invention, the control unit with the LED components applied according to the invention forms a fully functional semiconductor lamp unit which can be applied to a heat sink or to a carrier strip which is also designated as lead frame. Since the temperature resistance of integrated circuits corresponds to the permissible operating temperature of the LEDs, it is particularly easy to carry out a standardized further processing on a suitable heat sink or a lead frame with this combination according to the invention.

For this purpose, a carrier strip with two mutually parallel mounting bars and with a plurality of carrier elements each having at least one mounting surface for receiving an LED module is preferably proposed, wherein the carrier elements are each connected via connecting webs with the two mounting webs. The two mounting webs are each provided with mounting means, in particular with mounting holes, for attachment to a housing or heat sink. For a good dissipation of the heat loss of the LEDs, the carrier strip may for example consist of aluminum or copper or of a copper alloy.

According to a further particularly advantageous embodiment of the invention, it is provided that the LED module comprises at least one thermal contact element, with which the LED components are thermally conductively connected and can be dissipated via the heat loss of the LED components in particular to a LED module receiving luminous unit.

It is particularly advantageous if the thermal contact element is formed by an open or closed housing made of a thermally conductive material, in which the control unit with the LED components, as well as optionally provided with other components of the LED module, in particular electrical connection means recorded , 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 have an arbitrarily shaped outer contour, which can be adapted to the requirements imposed on the lighting unit. Preferably, the housing consists of a good heat-conducting material, in particular of copper or aluminum or of corresponding alloys.

It is particularly advantageous if in or on the housing, a base made of a highly thermally conductive material is provided, on which the control unit is recorded with the attached LED components. The waste heat can then be removed via the base, which is preferably adapted specifically to the size of the control unit and the number of LEDs of the module, depending on the type of module recording either directly or indirectly via the housing on to the lighting unit. 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 can thus be completed by a suitably trained primary optics to a front side open housing to achieve a specific focus. In a particularly simple way, a plastic look can be used by clip-mounting in the housing.

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 the 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 in an opening or in a recess of the heat sink of the lighting unit is used, 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 required. 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 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. Also, the lighting unit can be configured as another motor vehicle lighting unit, such as a taillight and / or turn signal unit. 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 einer ersten Ausführungsform eines erfindungsgemäßen LED-Moduls von der Vorderseite;

Figur 2:

Darstellung des LED-Moduls aus Figur 1 von der Rückseite;

Figur 3:

dreidimensionale Darstellung einer zweiten Ausführungsform eines erfindungsgemäßen LED-Moduls;

Figur 4:

dreidimensionale Darstellung eines Kühlkörpers eines Leuchtaggregats mit drei LED-Modulen nach Figur 3; und

Figur 5:

Ausführungsbeispiel eines metallischen Trägerstreifens als Kühlkörper.

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

FIG. 1:

three-dimensional representation of a first embodiment of an LED module according to the invention from the front side;

FIG. 2:

Representation of the LED module FIG. 1 from the back;

FIG. 3:

three-dimensional representation of a second embodiment of an LED module according to the invention;

FIG. 4:

Three-dimensional representation of a heat sink of a lighting unit with three LED modules after FIG. 3 ; and

FIG. 5:

Embodiment of a metallic carrier strip as a heat sink.

Embodiments of the invention

That in the Figures 1 and 2 shown LED module 1 is intended for installation in a lighting unit, not shown here. 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 mounted in a 2x2 array on the surface of a control unit 7 of the LED module 1, which in turn directly attached to the base 4 is. In this way, the LED chips 6 are thermally conductively connected to the wall 5 of the module housing 2 via the control unit 7 and the base 4. 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 rear recess 3 of the module housing 2, a connection board 9 is received, which is connected to a running here as a flat cable connection cable 13, via the lines of the LED module 1 and thus in particular the LED chips 6 can be supplied with power. Via two insulating pins 11 passed through the base 4, the connection board 9 is connected to the control unit 7 and the LED chips 6 attached thereto. For this purpose, the front end surfaces of the contact pins 11 are connected by bonding wires 12 to the control unit 7. The rear end portions of the contact pins 11 each contact a recessed in the connection board 9 connector socket. Instead of a cable, other connection means 13 may be provided, such as connector or pins.

In order to complete the LED module 1 on the front side, 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 in FIG FIG. 3 is shown. In the case of the LED module 1 shown here, the four LED chips 6 are arranged next to one another in a row on the control unit 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 7 for controlling the LED components 6 is already integrated. The pre-assembled LED modules 1 are later particularly quickly and easily inserted into suitable recesses 15 of a heat sink 8 of a lighting unit. To ensure a particularly effective delivery of 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 in FIG. 4 shown heatsink 8 has three recesses 15 in order to record a total of three inventively prefabricated LED modules 1, each with an integrated control unit 7 non-positively. 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.

In the FIG. 5 a metallic carrier strip 20, a so-called lead frame is shown, 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 respectively mounting surfaces 41, 42, 43 are sketched, where the respective LED modules 1 can be applied for example by gluing or 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 the FIG. 5 are for the sake of clarity of the drawing, only two connecting webs 51, 52 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 (10)

1. LED module (1) having a plurality of LED components (6) which are arranged on at least one support element, a control unit (7) for driving LED components (6) being integrated in the LED module (1), characterized in that the control unit (7) is an integrated circuit (IC), in particular an ASIC, in that at least individual ones of the LED components (6) are fastened directly on the control unit (7) such that for these LED components (6) the control unit (7) forms the support element, and in that the control unit (7) forms with the LED components (6) a semiconductor luminaire unit which is applied to a heat sink (8) or to a support strip (lead frame) (20).
2. LED module according to Claim 1, characterized in that the control unit (7) comprises a silicon IC or a silicon carbide IC.
3. LED module according to one of the preceding claims, characterized in that sensor means for monitoring the function of the LED components (6), and/or compensating means for compensating an ageing of the LED components (6) are integrated in the control unit (7).
4. LED module according to one of the preceding claims, characterized in that the LED components (6) are bonded or soldered onto the control unit (7).
5. LED module according to one of the preceding claims, characterized in that the support strip comprises two mounting webs (21, 22), arranged parallel to one another and respectively provided with mounting means (23), in particular with mounting openings, as well as a plurality of support elements (31, 32, 33) each having at least one mounting surface (41, 42, 43) for holding an LED module (1), the support elements (31, 32, 33) being connected to the mounting webs (21, 22) via connecting webs (51, 52).
6. LED module according to one of the preceding claims, characterized in that it comprises at least one thermal contact element (2, 5) via which heat loss of the LED components (6) connected thereto in a thermally conducting fashion can be dissipated, in particular can be transmitted to a lighting unit accommodating the LED module.
7. LED module according to claim 6, characterized in that the thermal contact element is formed by an open or closed housing (2) which is made from a thermally conducting material and in which the control unit (7) is accommodated with the LED components (6) and further components, which may be provided, of the LED module (1) in particular electrical connection means (13).
8. Lighting unit having a plurality of LED components (6) and a heat sink (8) 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.
9. Lighting unit according to Claim 8 with an LED module, according to Claim 7, characterized in that the at least one LED module (1) comprises a housing (2, 5) which is accommodated in the heat sink (8) with an interference fit, in particular is inserted, preferably pressed, into an opening or cutout (15) in the heat sink (8).
10. Lighting unit according to Claim 8 or 9, characterized in that it is designed as a spotlight, in particular as a motor vehicle headlight, which has a headlight heat sink (8) in which at least one LED module (1) is accommodated, preferably pressed in by means of a module housing (2, 5).

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