EP3180563A1

EP3180563A1 - Led holder for holding an led module

Info

Publication number: EP3180563A1
Application number: EP15750396.2A
Authority: EP
Inventors: Luca Bordin; Arnulf Rupp
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2014-08-12
Filing date: 2015-08-10
Publication date: 2017-06-21
Also published as: US20170219195A1; DE102014215985A1; WO2016023870A1

Abstract

The invention relates to an LED holder (11; 31; 41) for holding an LED module (23), having a leadframe (12; 32; 42) which is populated with electric and/or electronic components (29) for operating the LED module (23). The leadframe (12; 32; 42) is at least partly surrounded by a potting material (13; 33; 43) and has at least two exposed first contact regions (17) for electrically contacting the LED module (23) and at least two exposed second contact regions (20; 44) for an electric contact. A method for producing an LED holder (11) has the following steps: providing a leadframe (12) by adapting a basic leadframe shape, populating the leadframe (12) with electric and/or electronic components (29), and overmolding the leadframe (12) with a potting material (13) such that at least two first contact regions (17) for electrically contacting an LED module (23) and at least two second contact regions (20; 44) are exposed.

Description

description

LED Holder for Holding an LED Module The invention relates to an LED holder for holding an LED module having a leadframe. The invention also relates to a light generating device, comprising at least one LED holder, on which at least one LED module

is arranged, which LED module is equipped or equipped with at least one LED. The invention further relates to a method for producing an LED holder. The invention also relates to a method for providing a

Light-generating device. The invention is particularly applicable to LED spotlights and LED headlights.

There are LED light generators (so-called "light engines") are known in which multiple LEDs and a drive or

Driver electronics, possibly with sensors, are arranged on a common board and at least the driver electronics is covered by a housing. The LEDs can be equipped as LED chips in the so-called chip-on-board ("CoB") on the circuit board These LED light generators are

comparatively complex in their design, especially in a redesign, and also expensive to manufacture.

There is also known an LED light generator in which the LED module has its own housing, but none

Driver electronics. Rather, the LED module must be externally connected to driver electronics of the LED light generator, e.g. via suitable cables. The disadvantage here is the limited or missing functionality, in particular due to lack of sensors such as temperature sensors.

An LED module is understood in particular to mean a unit of a plurality of interconnected LEDs.

It is the object of the present invention to overcome the disadvantages of the prior art at least partially and In particular, to provide an inexpensive manufacturable LED light generator with high functionality.

This object is achieved according to the characteristics of the independent

Claims solved. Preferred embodiments are

in particular the dependent claims.

The object is achieved by a holder (hereinafter referred to as "LED holder" without restriction of generality) for holding an LED module, comprising a leadframe which is equipped with electrical and / or electronic components for operating the LED module, wherein the leadframe is at least partially surrounded by potting material and at least two exposed first contact areas for electrically contacting the LED module and at least two exposed second contact areas for electrical

Having contact.

Such an LED holder has the advantage that the shape of the leadframe (sometimes also referred to as a punched grid) can be retained by the potting material even under external mechanical stress. Depending on the chosen elasticity and / or stiffness of the potting material, the LED holder may be elastically yielding or practically stiff. In addition, the potting material protects the leadframe against corrosion and abrasion in a particularly effective manner. In addition, an electrically insulating potting material ensures a secure

Handling the LED holder. Furthermore, potting material is particularly inexpensive attachable to the leadframe. The

Potting material preferably has a high thermal conductivity.

In general, such an LED holder also makes it possible to use particularly simple production methods. Thus, the leadframe enables a particularly inexpensive

Provision of electrical wiring. In addition, inexpensive materials can be used for the potting material, for example plastic such as silicone, polybutylene terephthalate (Abbreviation PBT), polycaprolactam (abbreviation PA6) or polycarbonate (abbreviation PC), etc. On a separate

Retaining element can advantageously be dispensed with, since the LED holder is self-supporting.

Due to the fact that the LED module and the LED holder are made independently and then

can be brought together, an optical property can be easily adjusted by replacing a typically inexpensive LED module. In particular, LED modules may have different LEDs, for example, in terms of color, power and / or number, and / or with any sensors, e.g. Temperature sensors, the holder can be easily added or replaced. The presence of a

Temperature sensor allows, for example, a particularly efficient thermal management.

Electrical components may e.g. resistors,

Capacitors, coils, diodes, oscillators, etc. include. The electrical components are for a simple

Assembly prefers Surface Mounted Devices (SMDs). Electronic devices may include, for example, integrated devices such as microcontrollers, FPGAs, ASICs, and so on. In particular, integrated components may also be in the form of bare chips or "bare dies." The leadframe may, however, also be equipped with an antenna, etc.

be equipped, e.g. for wireless communication. The

electrical and / or electronic components may in particular constitute a driver electronics or a part thereof.

The potting material may in particular be an injection-moldable potting material. If the potting material has been applied by means of an injection molding process, it may also be referred to as "overmolding".

The second contact areas serve a different electrical contact than that of the LED module, in particular for Contacting a connection element such as a

Power supply line and / or a data line. The contacting may be solvable or insoluble. The second contact regions are arranged for easy contacting, in particular on a side edge of the leadframe or of the LED holder.

The structure of the leadframe or lead frame is not limited and may be made of, for example, a copper alloy, steel, brass, etc., and e.g. coated with nickel, silver, tin, etc.

It is an embodiment that the LED holder has at least one opening for insertion or passage of a respective LED module, in particular a central opening. A shape of the opening is arbitrary and may be e.g. be circular or angular. It preferably corresponds to a shape and size of a Lichtabstrahlbereichs the LED module. In particular, the opening may comprise an opening in the potting material which is congruent to an opening in the leadframe. The opening in the potting material is preferably slightly smaller than the opening in the leadframe, so that a

Projection of the potting material in the opening in the

Leadframe can serve as a plant or stop and / or for accurate positioning of the LED module.

The LED holder may have a top view of the opening

Have annular outer contour, in particular if the leadframe has three second contact areas. The

annular outer contour may in particular a

be circular or an oval outer contour.

It is a further development that the leadframe and / or the LED holder has, in accordance with a number n> = 3, in particular n = 3, second contact regions an outer contour which is n-sided in plan view of the opening. One of Contact area may be used for example for reading sensor data of a temperature sensor.

The potting material may in particular for the case that a second contact area of the leadframe a line terminal

For example, a "wire trap" may be formed therein with a support mechanism for holding a conduit in the conduit clamp, such as a latching tab The retention mechanism may include, for example, a release mechanism for releasing the otherwise trapped conduit.

The potting material may be designed to be at least partially reflective for an increased light output or for a reduced loss of light. This is especially true if the LED holder is intended to be used in a retroreflective environment. The reflective property may be, for example, diffuse or specular

reflective coating can be achieved. The LED holder may be attached to it (e.g.

Heatsink) in particular holding tabs, the e.g. Have holes for the passage of fasteners, e.g. Screw holes. The LED holder likes for this purpose alternatively or additionally elsewhere

Have fasteners, e.g. Locking pins, clamps, etc. The fasteners in particular through

be formed correspondingly shaped attachment areas of the potting compound. The LED holder may also be used to attach the at least one LED module serving fasteners or

Have attachment regions, e.g. Hooks, clamps or snap tabs. This may facilitate mounting the LED holder equipped with the LED module.

It is a further embodiment that at least one second contact region is formed as a line terminal is. This allows a particularly simple and secure contacting of simple cables, in particular of wires.

It is yet another embodiment that at least a second contact area as a plug connection (plug,

Bush, etc.) is formed. This allows more complex connections to be used, e.g. multipolar connections, e.g. for connecting a coaxial cable or a bus capable

Plug-in element (for example, a USB connector, a Firewire connector, a Lightning connector, an Ethernet cable

(e.g., designed as a Power over Ethernet cable), etc.). The element which can be connected to the at least one second contact region (coaxial cable, bus-capable plug-in element, data cable, etc.) may also be permanently attached thereto, e.g. be soldered.

The second contact areas may be for a particular

simple production by forming a leadframe basic shape are provided, e.g. by bending over predefined regions of the leadframe basic shape. You can, however, e.g. also by an inseparable attachment of a previously produced contact element with the leadframe before its encapsulation,

in particular overmolding. The insoluble attachment may e.g. by welding, in particular

Laser welding, are produced. In particular, the lead frame basic form may be a quasi-endless leadframe band.

Advantageously, at least one, preferably all second contact regions are formed such that one is attached thereto

connected line tangent to an outer edge or outside of the leadframe in the contact area and is guided away, i. with a straight edge parallel to this and with a curved edge,

for example, tangentially at an annular leadframe, i. perpendicular to a radial direction, in particular also in all cases parallel to the mounting surface of the leadframe.

As a result, a space-saving arrangement is achieved in the small radii of curvature of the connection lines can be avoided.

It is also an embodiment that at least one first contact region is formed as a resilient contact tab. The LED module, in particular contact fields thereof, can be pressed on it, which is a particularly simple

Contacting possible. The at least one springy

Contact tab may extend in particular into the opening of the LED holder. Such contact tabs enable

a particularly simple way of pressing the LED module to a support due to a spring-back force

Contact tabs. It is a development that the LED module is housed in the LED holder.

The object is also achieved by a light generating ^¬ device, comprising at least one LED holder as described above, on which at least one LED module arranged, in particular fixed, is. The leadframe of the LED holder is electrically connected via its first contact areas with the LED module. The LED module is equipped with at least one light emitting diode (LED). If several LEDs are present, they can be lit in the same color or in different colors. A color can be monochrome (eg red, green, blue etc.) or multichrome (eg white). Also, the light emitted by the at least one light emitting diode, an infrared light

(IR-LED) or an ultraviolet light (UV-LED). Several light emitting diodes can produce a mixed light; e.g. a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor

(Conversion LED). The phosphor may alternatively or additionally be arranged away from the light-emitting diode

("Remote Phosphor"). The at least one light emitting diode may be in the form of at least one individually housed light emitting diode or in ₀

Form present at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, e.g. at least one Fresnel lens,

Collimator, and so on. Instead of or in addition to inorganic light emitting diodes, e.g. based on InGaN or AlInGaP, organic LEDs (OLEDs, for example polymer OLEDs) can generally also be used.

In particular, the light-generating device may be

Light generator or "light engine" be.

It is an embodiment that the LED module is a CoB module. In this case, a substrate, in particular a

PCB, be equipped with at least one LED chip. Furthermore, at least two contact fields for contacting the first contact regions of the LED holder may be present on the substrate.

The at least one LED, in particular LED chip, may be encapsulated, in particular with a light-transmissive potting material containing e.g. Epoxy or silicone.

The LED module may be an electronic carrier, which allows a particularly simple and inexpensive design.

Alternatively, the LED module may be part of electronics for operating the at least one LED of the LED module

("Driver electronics").

It is yet another refinement that the LED module has at least one sensor for the thermal management of the LEDs or of the LED module, in particular a temperature sensor, and / or at least one coding device. Of the

Temperature sensor may be eg an NTC resistor. The LED module may also be very accurate, for example

Setting a color location of the LED module

radiated light have at least one color sensor. Also, the LED module for brightness control may e.g. have a brightness sensor.

The LED module may alternatively or additionally comprise at least one component as one or part of a coding device which serves to identify it by the LED carrier or the electronics arranged thereon, e.g. a resistor with one for the type of LED module

certain value. The resistance may be, for example

Current limiting or current setting resistor, by means of which, for example, at a fixed supply voltage, the operating current for the LEDs of the specific LED module is adjustable.

The light generating device may be attached to a heat sink such that the LED holder presses the at least one LED module onto the heat sink. In particular, the LED module may press with its front side against the associated first contact regions and rest with its rear side against the heat sink. The LED holder is preferably also with its back or with the back of the overmolded leadframe on the heat sink. The

Pressing force, by means of which the LED holder presses the LED module onto the heat sink, may result, in particular, from an elastic restoring force of the first contact areas bent by the pressing of the LED module.

The heat sink may be a component of the light generation device ^¬. Instead of the heat sink likes the

Light generation device but also at each other

be attached to a suitable pad.

Thus, a direct, effective cooling of the housed in the housing components can be achieved, for example by placing the equipped with at least one LED module LED holder with its open back on a heat sink. For example, such a side facing away from the LEDs back of the LED module sit directly and not only on a rear housing wall on the heat sink and thereby cooled.

The light generating device may further include a housing

have, which covers at least a part of the LED holder. The housing may in particular cover a part of the LED holder which has exposed (not molded) electrical and / or electronic components. The housing may in particular have a translucent opening, in particular a central translucent

Opening.

The object is further achieved by a method for

Produce an LED holder as described above.

In particular, the method may include at least the following steps: providing a lead frame by adapting a lead frame basic form; Equipping the leadframe with electrical and / or electronic components; and encapsulating the leadframe with a potting material so that at least two first contact areas for electrical

Contacting the LED module and at least two second

Exposing contact areas.

The steps of placement and overmolding may be in this order or in reverse order

be performed. If the placement is carried out before the encapsulation, all electrical and / or electronic components may be encapsulated, only a part of the electrical and / or electronic components are encapsulated or none of the electrical and / or electronic components are encapsulated. If the encapsulation is carried out before fitting, contact regions of the leadframe for making contact with the at least one are also in particular

electrical and / or electronic device during the Enveloping kept free and kept the first and the second contact areas.

The method gives the same advantages as the LED holder and can be made analog.

In particular, the leadframe basic form can be inexpensive

mass produced, e.g. as a quasi-endless band.

The adaptation of the leadframe basic shape, so that it is suitable for use in the LED holder, for example, may include a partial step of unifying the leadframe from the

Leadframe basic shape along a desired outer contour of the leadframe and / or a separation of traces for

Producing a desired interconnection arrangement of

Include leadframes. The separation may be e.g. done by punching, laser cutting, etc. The fitting may also be a bending over to make one, for example

Include line clamp and / or a contact tab or contact spring.

An additional step may be to firmly connect at least one terminal, e.g. a previously made

Line terminal or a connector, with previously separated leadframe include.

It is still a possible step that the encapsulation of the leadframe with the potting material is followed by a step of severing at least one conductor track of the leadframe. As a result, the routing of the leadframe can be formed even more diverse. In particular, the leadframe can be divided into two or more separate parts without falling apart, since the parts are mechanically held together by the encapsulation. This allows, for example, an admission of the

different parts with different voltages. At least one of the parts, in particular at least two of the Parts may be contactable by means of a contact tab or contact spring.

The method may also include a step of testing the LED holder.

A method for providing a

Light generating device, in particular one

Light generator, in particular, the following steps

comprising: (i) attaching at least one LED module to a backside of the LED holder so as to make electrical contact across the first contact areas therebetween; and (ii) mounting the backside of the LED holder with the LED module a pad so that the LED holder presses the LED module on the pad.

The above-described characteristics, features and advantages of this invention as well as the manner in which they are achieved will become clearer and more clearly understood

In connection with the following schematic description of exemplary embodiments that are associated with the

Drawings are explained in more detail. It can to

Clarity identical or equivalent elements must be provided with the same reference numerals.

Fig.l shows a plan view in section a

LED holder according to a first embodiment;

2 shows a top view in a sectional view of a

LED holder according to a second embodiment; and

3 shows a plan view in a sectional view of a

LED holder according to a third embodiment.

Fig.l shows an LED holder 11 after a first

Embodiment with a lead frame 12 and a the

Leadframe 12 at least largely surrounding encapsulation 13 of an injection-moldable plastic. The leadframe 12 and its encapsulation 13 and thus also the LED holder 11 have an annular basic shape. The leadframe 12 has for this purpose a circular central recess 14, which is arranged concentrically to a circular central recess 15 of the encapsulation 13. In the by the

Recesses 14, 15 limited opening 16 protrude first

Contact areas in the form of resilient contact lugs 17. The contact lugs 17 are here distributed equidistant around the circumference of the opening 16 and the recess 14 of the leadframe 12. The contact tabs 17 in particular by a punching and / or forming process of a leadframe basic shape

have been produced.

The leadframe 12 has a basically circular

Outer contour 19, wherein a second contact region in the form of a wire trap 20 adjoins the outer side at three peripherally equidistantly distributed locations, and the conductor terminals 20 may also be formed from a leadframe basic shape by means of a stamping and / or forming process

have been produced. They may alternatively be separate

and then inextricably connected to the remaining leadframe 12, e.g. by laser welding, soldering, etc.

The line terminals 20 are on the outside so through the

Encapsulation 13 encapsulates that an introduction or a

Outlet of connection cables Wl, W2, W3 in the line terminals 20 is possible. In addition, the encapsulation 13 likes there

For example, one with an insertion opening 21 of

Line terminals 20 congruent insertion hole 22 have. The connection cables W1, W2, W3 may be firmly connected to the line terminals 20, e.g. by soldering or welding, or may be releasably supported therein, e.g. by a clamp or a releasable locking. The connecting cables Wl, W2, W3 can be supplied with

electrical energy and / or serve for data transmission.

The leadframe 12 is equipped with electrical and / or electronic components 29, which are used to operate one in the LED Holder 11 to be used LED module 23 are provided. In other words, one is the electrical and / or

electronic components 29 having driver electronics at least partially integrated into the LED carrier 11. In particular, the electrical and / or electronic components 29 may not be surrounded or encapsulated by the encapsulation 13, which improves their heat dissipation.

An LED module 23 is provided for holding by the LED holder 11. The LED module 23 has a substrate 24, e.g. a printed circuit board or a printed circuit board

Ceramic substrate. Arranged centrally on a front side of the substrate 24 are LEDs (not shown), which are provided by a potting compound 25 containing phosphor, e.g. made of silicone, are covered. Outside the potting compound 25, a plurality of, here: four, contact fields 26 are present on the substrate 24 on the front side. These are electrically connected via printed conductors with the LEDs for their operation. Also, two of the contact pads 26 are connected to the two terminals of a temperature sensor, e.g. an NTC resistor 27, connected. By means of the NTC resistor 27, e.g. a thermal management of the LED chips are made possible. In addition or as an alternative to the NTC sensor 27, for example, a coding element in the form of e.g. a coding resistor for identifying the LED module 23 may be present. Overall, the more than two-fold electrical contacting of the LED module 23 allows independent operation of multiple strands of LEDs, e.g. different color, e.g. red, green or blue. The LEDs are preferably LED chips (sometimes also referred to as unhoused LD chips), so that the LED module 23 is designed as a CoB ("chip-on-board") module

Tracks, etc. on. Another application is that to power the electronics on the LED holder 11 a

Center tap is connected to a contact tab.

For marriage of LED holder 11 and LED module 23, the LED module 23 is inserted with its front side into the recess 14 of the leadframe 12 such that the phosphor containing potting compound 25 projects into or through the recess 14, while the contact pads 26 are pressed against the contact tabs 17, which are thereby elastically bent. The contact tabs 17 thus serve for electrical

Contacting corresponding contact fields 26 of the LED module 23 and for generating a pressing force on the LED module 23 in the rearward direction. The substrate 24 of the LED module 23 also has two mounting holes 28 for mounting the LED module 23 to the LED carrier 11, e.g. by means of a

Hot caulking, crushing, etc.

The LED holder 11 and the LED module 23 together form a light generating device, in particular a light engine or light generator 11, 23. The light generator 11, 23 can be placed with its back on a base and attached thereto. The pad is preferably a heat sink (not shown). For mounting the LED holder 11, mounting holes 30 are provided in the leadframe 12 and in the overmold 13 in order to secure the LED holder 11, e.g. by means of a

Fasten screw.

2 shows a plan view in sectional view of an LED holder 31 according to a second embodiment. The LED holder 31 is constructed similarly to the LED holder 11. In contrast to the LED holder 11, however, the LED holder 31 has a leadframe 32 with an encapsulation 33, each having a four-sided, in particular square, outer contour 34 in plan view. At each of the four straight sides of the outer contour 34 each includes an overmolded

Line terminal 20 on the outside. In the line terminals 20 each one of four wires or cables Wl to W4 are used.

3 shows a sectional plan view of an LED holder 41 according to a third exemplary embodiment. The LED holder 41 is constructed similarly to the LED holder 11, but differs in that a second

overmolded contact area of the associated leadframe 43 as an electrical plug connection is formed. This

Plug connection is designed here as a bus-like connection in the form of a USB connection 44. For example, a USB device 45 may be connected to the USB port 44, e.g. a USB memory stick, a radio transmitter / receiver, e.g. for upgrading as Wifi and / or Bluetooth device, or also a USB cable for wired communication.

Although the invention is shown in detail by the

Embodiments have been further illustrated and described, the invention is not limited thereto and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. Also like the LED module a part (but not all) of the electrical and / or electronic components of a

Have driver circuit.

Generally, "on", "an", etc. may be taken to mean a singular or a plurality, in particular in the sense of "at least one" or "one or more", etc., as long as this is not explicitly excluded, eg by the expression "exactly a ", etc. Also, a number can include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

Reference sign

11 LED holders

12 lead frame

13 overmoulding

14 recess of the leadframe

15 recess of the encapsulation

16 Opening of the LED holder

17 contact tab

19 outer contour of the leadframe

20 line terminal

21 Entry opening of the cable clamp

22 insertion hole in the encapsulation

23 LED module

24 substrate

25 potting compound

26 contact field

27 temperature sensor

28 mounting hole

29 Electrical and / or electronic component

30 mounting hole

31 LED holder

32 leadframe

33 overmoulding

34 outer contour

41 LED holder

42 encapsulation

43 leadframe

44 USB port

45 USB device

Wl connection cable

W2 connection cable

W3 connection cable

W4 connection cable

Claims

claims

1. LED holder (11; 31; 41) for holding an LED module

(23), comprising

a leadframe (12; 32; 42) equipped with electrical and / or electronic components (29) for operating the LED module (23),

wherein the leadframe (12; 32; 42) is at least partially surrounded by potting material (13; 33; 43) and at least two exposed first contact regions (17) for electrically contacting the LED module (23) and at least two exposed second contact regions (20 44) for electrical

Having contact.

An LED holder (11; 31; 41) according to claim 1, having a central opening (16) for passing the LED module (23).

LED holder (11; 31; 41) according to one of the preceding claims, wherein at least one second contact region (20, 44) is formed as a line clamp (20).

LED holder (41) according to one of the preceding claims, wherein at least one second contact region (20, 44) is designed as a plug connection (44).

LED holder (11; 31; 41) according to one of the preceding claims, wherein the second contact regions (22, 44) are formed from a leadframe base body by deformation

have been produced.

LED holder (11; 31; 41) according to one of the preceding claims, wherein the second contact regions (22, 44) are manufactured separately and then firmly fixed to the leadframe (12;

32; 42) have been connected.

LED holder (11; 31; 41) according to one of the preceding claims, wherein at least one first contact region is formed as a resilient contact lug (22).

An LED holder (11; 31; 41) as claimed in any one of the preceding claims, wherein the LED holder (11; 31; 41) is adapted to be back-mounted on a base

is set up. A light generating device (11, 23, 31, 23, 41, 23) comprising at least one LED holder (11, 31, 41) according to any one of the preceding claims, to which

at least one LED module (23) is arranged.

A light generating device (11, 23, 31, 23, 41, 23) according to claim 9, wherein the LED module (23) is a CoB module.

A light generating device (11, 23, 31, 23, 41, 23) according to any one of claims 9 to 10, wherein the LED module (23) is an electronically-less carrier.

A light generating device (11,23; 31,23; 41,23) according to any one of claims 9 to 10, wherein the LED module (23) comprises part of electronics for operating the at least one LED of the LED module (23).

A light generating device (11, 23, 31, 23, 41, 23) according to any one of claims 9 to 12, wherein the LED module (23) comprises at least one temperature sensor (27) and / or

Has at least one coding device.

A light generating device (11, 23, 31, 23, 41, 23) according to claim 13, wherein said encoding means comprises

Current limiting resistor has.

A method of manufacturing an LED holder (11; 31; 41) according to any one of claims 1 to 9, said method comprising at least the following steps: Providing a lead frame (12; 32; 42) by adapting a lead frame basic form,

- Equipping the lead frame (12; 32; 42) with

electrical and / or electronic components (19) and

- Overmolding the leadframe (12; 32; 42) with a

Potting material (13; 33; 43) such that at least two first contact areas (17) for electrical

Contacting an LED module (23) and at least two second contact areas (20; 44) exposed.