EP3453234A1

EP3453234A1 - Multi-led system

Info

Publication number: EP3453234A1
Application number: EP17718834.9A
Authority: EP
Inventors: Thomas Feichtinger; Franz Rinner
Original assignee: TDK Electronics AG
Current assignee: TDK Electronics AG
Priority date: 2016-05-06
Filing date: 2017-03-30
Publication date: 2019-03-13
Also published as: TWI726087B; JP6874022B2; CN109479370A; WO2017190895A1; DE102016108427A1; CN109479370B; US10714458B2; TW201743429A; US20190148346A1; JP2019515507A

Abstract

A multi-LED system comprises a support (2) and a plurality of light emitting diodes (3, 3', 3") on the support (2). The support (2) comprises a base (4) in which a plurality of electrical components (11, 11', 11", 12) are embedded. For example, the base (4) contains a resin material and/or a polymer material. The multi-LED system (1) can in particular be a quad LED flash module.

Description

description

Multi-LED System The present invention relates to a multi-LED system, which is designed, for example, to generate a flashlight. Such multi-LED systems are needed in particular for mobile applications such as smart phones or digital cameras.

They are multi-LED systems comprising a hybrid construction of a substrate and a passive assembly

Components and with several light emitting diodes (LEDs) known. The LEDs are covered for example with light conversion layers, so that, for example, a combination of

Warm white light and cold-white light is generated.

To protect the LEDs from electrostatic discharges (ESD, Electrostatic Discharge) discrete components with varistor function can be used, but lead to a larger size. The publication DE 10 2014 101 092 AI shows a chip with varistor function, on which an LED can be mounted. It is an object of the present invention to provide a multi-LED system with improved properties.

The multi-LED system according to the invention has a carrier on which a plurality of light-emitting diodes are arranged. The carrier has a base body in which a plurality of electrical

Components are embedded. In particular, the multi-LED system is used as

Flash module designed in mobile applications. In a

Embodiment, the multi-LED system has exactly four

LEDs on. In particular, it can be a quadruple LED flash module. The LEDs are arranged, for example, at the vertices of a rectangle, for example a square.

By embedding the components in the carrier, the module size can be significantly reduced or more LEDs in the same module size can be integrated, whereby the flash output can be significantly increased. The integration of the components also prevents that in the lateral emission by reflection on the

Components the light color and light intensity is changed.

This significantly improves the light output and color quality of the photos in mobile camera applications. For example, apart from the light-emitting diodes, no further electrical component is arranged on the carrier.

The embedded electrical components are, for example, one or more sensors and / or protective components. The components may comprise a ceramic material. For example, at least one ESD protection component for protection against electrostatic discharges (ESD) is present. It may be a varistor, in particular a multilayer varistor, or a TVS diode. Alternatively or additionally, a

Component for protection against overcurrents, such as a PTC device, and / or a device for protection against elevated temperatures, such as an NTC device, be present. The main body has, for example, a resin material and / or a polymer material. The resin or

Polymer material may have fillers. By adding the fillers, for example, the hardness, the

Thermal expansion coefficient and / or the thermal

Conductivity of the body can be influenced.

For example, the thermal expansion coefficient of

Body adapted to the thermal expansion coefficient of the LEDs. For example, the parent body is one

Glass fiber resin material on. In addition or as an alternative to the glass fiber material, the resin or polymer material may comprise, for example, ceramic fillers.

The main body can be multi-layered. All

Layers of the main body can be the resin or

Have polymer material. For example, the

An upper body, an upper, middle and lower layer, wherein the middle layer between the upper and lower layer is arranged. The components can be found in the

be embedded in the middle layer. In particular, the components may be arranged only in the middle layer and be covered by the upper and lower layers.

The carrier may have a plurality of upper and lower metallizations, respectively, on the top and the bottom of the

Base body are applied.

In particular, first upper metallizations for contacting the LEDs can be applied to the upper side of the main body. For example, the LEDs are disposed on the first upper metallizations and fixed to the first upper metallizations by soldering. For example, each LED is connected to two first upper metallizations, wherein one of the metallizations is designed for contacting two LEDs. Thus, two LEDs each share a first upper metallization. In a four-LED system, for example, there are exactly six first upper metallizations.

One or more embedded devices may also be connected to the first top metallizations. The embedded components are for example by means of

Vias with the first upper

Connected metallizations. For example, these are one or more ESD protection components.

Furthermore, on the upper side second upper Metalli ^¬ sierungen can be arranged, for example, the

Weitererkontaktierung one or more of the embedded components are formed. On the second upper

Metallizations in particular no component is arranged. The embedded components are connected, for example, by means of plated-through holes with the metallizations. The second upper metallizations are for example as

Traces formed. For example, two second upper metallizations in the form of a broken strip run from one edge of the multi-LED system to

opposite edge of the multi-LED system. The second upper metallizations are arranged, for example, between first upper metallizations.

In one embodiment, the multi-LED system includes a temperature sensor that is connected to the second upper

Metallizations is electrically connected. Of the

Temperature sensor is arranged for example in the supervision in a central region of the multi-LED system. Furthermore, lower metallizations for the electrical connection of the multi-LED system, in particular the LEDs and / or the embedded components may be arranged on the underside of the base body.

For example, on the bottom first lower

Metallizations for electrical connection of the LEDs

arranged. For example, each LED is connected to two first lower metallizations, one of which

Metalizations for contacting all LEDs can be formed. In a four-LED system, for example, there are exactly five first lower metallizations. The first lower metallizations are, for example, via first vias with the first upper ones

Metallizations electrically connected. It may be

in particular to act thermal vias, which is characterized by a high thermal conductivity. The first via contacts extend, for example, without interruption from the first upper metallization to the first lower metallization.

Furthermore, on the bottom second lower

Be arranged metallizations, which are formed for example for the electrical connection of one or more of the embedded components. For example, the second lower metallizations are arranged only in lateral edge regions on the underside of the carrier. For example, a first lower metallization is arranged between the second lower metallizations. The second lower metallizations are connected, for example, to the second upper metallizations by fourth through-contacts. For example, the fourth vias lead from the second upper metallizations to the second lower metallizations. In particular, the fourth vias may be uninterrupted from the second upper metallizations to the second lower ones

Lead metallizations. In one embodiment, the second lower metallizations are designed for the electrical connection of a temperature sensor.

In one embodiment, at least one of

embedded devices with at least one of the upper ones

Metallization connected by a via and the upper metallization connected to a lower metallization through a via. In particular, the embedded device may be connected to two upper metallizations by a via, respectively, and the two upper metallizations may be connected to two lower ones

Metallizations be connected by one via each. The embedded component is in particular only above the upper metallizations with lower

Metallizations connected and has no direct connection to the lower metallizations. Such

Connection structure allows for efficient and

Space-saving connection of the embedded component from the bottom.

In one embodiment, one or more metallic structures for reducing the thermal resistance are embedded in the main body. For example, it is about Metal blocks or metal strips. The metallic structures have, for example, copper. The vias may be interrupted by the metallic structures or pass through the metallic structures.

In accordance with another aspect of the present invention, an LED system is provided. Unlike the above

described multi-LED system, the LED system can have even a single LED. There may also be only a single embedded component. Alternatively, the LED system has a plurality of light-emitting diodes and / or a plurality of embedded components. All the features described above in relation to the multi-LED system

can - as far as appropriate - also be present in the LED system.

In particular, the carrier may have at least one upper

Metallization for connecting at least one of

embedded components and at least one lower one

Metallization for connecting the embedded device, wherein the embedded device is connected to the upper metallization through a via and wherein the upper metallization with the lower

Metallization is connected by a via. In particular, the embedded device may be connected to two upper metallizations by two vias and the two upper metallizations by two

Vias be connected to two lower metallizations.

In accordance with another aspect of the present invention, a support for a multi-LED system is provided. The carrier may be formed as described above. The carrier has a base body in which a plurality of electrical

Components are embedded. The carrier is designed to arrange a plurality of LEDs. In particular, a plurality of ESD protection components and at least one temperature sensor are embedded in the base body. The main body has, for example, a resin or polymer material.

In the present disclosure, several aspects of an invention are described. All the features related to the multi-LED system, the carrier and the LED system

are also disclosed accordingly with respect to the other aspects, even if the respective ones

Property is not explicitly mentioned in the context of the other aspects. Furthermore, the description of the subject matter specified here is not limited to the individual specific embodiments. Rather, the features of the individual embodiments, as far as technically feasible, can be combined. The objects described here are explained in more detail below with reference to schematic exemplary embodiments.

FIG. 1A shows an embodiment of a multi-LED system in a plan view,

FIG. 1B shows the embodiment of the multi-LED system from FIG

1A in perspective view,

Figure IC, the embodiment of the multi-LED system of FIG

1A in horizontal section in a plan view, FIG. 1D shows the embodiment of the multi-LED system from FIG. 1A in horizontal section in a perspective view,

Figure 2A shows another embodiment of a multi-LED

Systems in perspective view,

FIG. 2B shows the embodiment of the multi-LED system from FIG

2A in horizontal section in perspective view.

Preferably, like reference numerals refer to functionally or structurally corresponding parts of the various embodiments in the following figures.

FIG. 1A shows a multi-LED system 1 in a plan view.

FIG. 1B shows the multi-LED system 1 in a perspective view.

The multi-LED system 1 has a carrier 2, on which a plurality of light-emitting diodes 3, 3 ', 3' 'are arranged. For reasons of better representability, the lower right quarter of the system 1 is not shown. This quarter is formed, for example, axis mirrored to the lower left quarter.

The light-emitting diodes 3, 3 ', 3' 'are indicated by dashed lines

Outlines indicated. The light emitting diodes 3, 3 ', 3 "may be covered by optical structures, for example lenses and / or light conversion layers, and / or protective structures. The multi-LED system 1 has, for example, exactly four LEDs. The multi-LED system 1 is used, for example, to generate a flash. In one embodiment, the LED system 1, apart from the LEDs 3, 3 ', 3 ", has no further discrete components on the carrier 2. This allows a particularly good miniaturization of the LED system 1. In addition, thereby the light output and the homogeneity of the emitted light can be improved. In particular, there is no shading and color change by further

Surface mounted components on.

The carrier 2 has a main body 4 (FIG. 1B), which in the present case is made transparent for reasons of representability. The main body 4 may be multi-layered, z. B. be constructed in three layers. The main body 4 has

For example, a resin material, in particular a glass fiber resin material. In addition to or as an alternative to the glass fiber material, the resin material may include ceramic fillers

exhibit. The main body 4 may also comprise a polymer material, in particular a filled polymer material.

In general, the base body 4 may comprise at least one material from a group consisting of resin, in particular bismaleimide-triazine resin, polymers, glass, in particular

Glass fibers, prepreg material, polyimide, a liquid crystal polymer, cyanate ester, epoxide-based build-up film, FR4

Material, a ceramic, and a metal oxide. In this case, the main body 4 in addition to a base material, such. As resin or a polymer, further fillers. FR4 denotes a class of composites consisting of epoxy resin and glass fiber fabric. Resin-glass fiber laminates are characterized by a high dielectric strength and a high mechanical strength. Furthermore, the material of the base body 4 may be selected such that soldering processes are enabled at higher temperatures. For example, the LEDs 3, 3 ', 3''are soldered to the carrier 2. The material of the base body 4 is particularly suitable for soldering processes at 320 ° C, for example, occur during reflow soldering with a gold-tin solder paste. For example, the gold-tin solder paste has 80% gold and 20% tin.

Alternatively, for example, a SnAgCu solder paste can be used which is soldered at temperatures around 260 ° C.

On an upper side of the main body 4 a plurality of upper metallizations 5, 5 '6, 6' are arranged. On an underside of the main body 4 a plurality of lower metallizations 7, 7 '8, 8' (Figure IC) are arranged. The upper metallizations 5, 5 '6, 6' are separated from each other by column 9. The lower metallizations 7, 7 '8, 8' are separated from each other by column 10. First upper metallizations 5, 5 'are as

Contact surfaces for contacting the LEDs 3, 3 ', 3' '

educated. Second upper metallizations 6, 6 'are designed as further contacting of an embedded component 12. The lower metallizations 7, 7 ^x are as

Connection surfaces for electrical connection of the multi-LED

Systems, in particular the LEDs 3, 3 ', 3''and the ^{eingebette ¬} th components.

In FIGS. 1A and 1B, the local thermal resistance in K / W determined by thermal simulation is plotted in a range from 1 K / W to 12 K / W. It turns out that the thermal resistance in the vicinity of a gap 9 between the first upper metallizations 5, 5 'is greatest. Figure IC shows the multi-LED system 1 of Figures 1A and 1B in a horizontal section in a plan view. Figure 1D shows the multi-LED system 1 in horizontal section in a perspective view.

In the main body 4, in particular in a middle layer of the base body 4, a plurality of electrical components 11, 11 ', 11' ', 12 are embedded. The components 11, 11 ', 11' ', 12 are completely embedded in the carrier 2. For example, the components 11, 11 ', 11 ", 12 are completely embedded in the middle layer of the main body 4 and arranged between the upper and lower layers of the main body 4. The electrical components 11, 11 ', 11' ', 12 are

especially ultrathin. The height can be, for example, less than or equal to 0.33 mm.

In the present embodiment, a plurality of ESD protection components 11, 11 ', 11 "and a temperature sensor 12 are embedded in the carrier 2.

In particular, exactly one ESD protection component 11, 11 ', 11 "is present for each LED 3, 3', 3". There are two ESD protection components 11, 11 ', 11' 'between two adjacent LEDs 3, 3', 3 '' as seen in the plan view.

arranged.

The ESD protection components 11, 11 ', 11 "have, for example, a ceramic. The ceramics are

in particular a varistor ceramic, for example

doped ZnO, SrTiO 2 or SiC. The temperature sensor 12 is designed as an NTC component. For example, the temperature sensor 12 comprises a ceramic. The temperature sensor 12 is arranged in the top view in the center of the multi-LED system 1.

The LEDs 3, 3 ', 3''are arranged on the first upper Metalli ^¬ sierungen 5, 5' and electrically with these

connected. The first upper metallizations 5, 5 'are connected to the first lower metallizations 7, 7' by first plated-through holes 13, 13 '. In this case, four first plated-through holes 13, 13 'are present for each LED 3, 3', 3 ". The first vias 13, 13 'extend without interruption from the first upper metallizations 5, 5' to the first lower metallizations 7, 7 '. In each case two of the LEDs 3, 3 ', 3' 'share a first upper metallization 5'. In the example shown, exactly six first upper metallizations 5, 5 'are present. All LEDs 3, 3 ', 3' 'share a first lower metallization 7'. In the example shown, exactly five first lower ones

Metallizations 7, 7 'present.

The first plated-through holes 13, 13 'have, for example, diameters between 100 and 200 μm, preferably between 130 and 170 μm. In particular, the diameters can be at 150 ym. The first plated-through holes 13, 13 'are formed for example as thermal vias, which reduce the thermal resistance of the carrier 2. The

Through holes 13, 13 'have, for example, copper. The plated-through holes 13, 13 'are in particular completely filled thermal copper vias.

The varistors 11, 11 ', 11''are connected to the first upper and second through-contacts 14, 14' (FIG first lower metallizations 5, 5 '7, 7' connected. In this case, the plated-through holes 14, 14 'each extend from a varistor 11, 11' 11 '' to the first upper one

Metallizations 5, 5 'or of a varistor 11, 11' 11 '' to the first lower metallizations 7, 7 '.

The temperature sensor 12 is connected to the second upper metallizations 6, 6 'by third plated-through holes 15, 15'. The third vias 15, 15 '

extend from an upper surface of the temperature sensor 12 to the second upper metallizations 6, 6 '.

The second upper metallizations 6, 6 'are through fourth plated-through holes 16, 16' with the second lower

Metallizations 8, 8 'connected. The fourth vias 16, 16 'extend from the second upper metallizations 6, 6' to the second lower ones

Metallizations 8, 8 '. The fourth plated-through holes 16, 16 'are arranged in the plan view in an edge region of the carrier 2.

The second upper metallizations 6, 6 'run as a gap interrupted by a strip of the strip

Carrier 2 to the opposite edge of the carrier 2. The second lower metallizations 8, 8 'are each arranged only in an edge region of the carrier 2. Between the second lower metallizations 8, 8 ', a first lower metallization 7' is arranged. The second, third and fourth plated-through holes 14, 14 '15, 15', 16, 16 'are, for example, copper or

Silver on. The second, third and fourth vias 14, 14 '15, 15' 16, 16 'may have a smaller one Diameter than the first vias 13, 13 ', for example, diameter between 40 and 100 ym, in particular between 40 and 70 ym. The LED system 1 has, for example, dimensions of 2.6 × 2, 6 mm ² . The thickness of the LED system 1 without LEDs is for example 300 ym. The varistors 11, 11 ', 11''and the temperature sensor 12 each have, for example, a thickness of 100 .mu.m.

Figures 2A and 2B show a further embodiment of a multi-LED system 1 in perspective view and in horizontal section in a perspective view. In contrast to the embodiment of FIGS. 1A to 1D, metallic structures 17, 17 ', 17 "are embedded in the carrier 2 for reducing the thermal resistance. The metallic structures 17, 17 '17' 'are in the form of

Blocks or strips formed. The metallic one

Structures 17, 17 'have copper, for example.

The metallic structures 17, 17 ', 17 "are, for example, embedded in a middle layer of the main body 4.

In particular, the metallic structures 17, 17 '17 "do not extend through the upper and lower layers of the

Base 4 through. The metallic structures 17, 17 ', 17''are connected to the first upper and first lower metallizations 5, 5', 7 'by first plated-through holes 18, 18'. The plated-through holes 18, 18 'may pass through the metallic structures 17, 17', 17 '' or be interrupted by the metallic structures 17, 17 ', 17''. The plated-through holes 18, 18 'can with the metallic structures 17, 17 '17''also in one piece

be educated.

The first vias 18, 18 'are formed corresponding to the first vias 13, 13' of the embodiment of FIGS. 1A to 1D. In contrast, however, only two plated-through holes 18, 18 'lead away from the first upper metallizations 5, 5' for each LED 3, 3 ', 3 ". Each via 18, 18 'is with a

embedded metallic structure 17, 17 '17''connected. In this case, two plated-through holes 18 'share a metallic structure 17. Overall, in the example shown, six metallic structures 17, 17', 17 '' are present. Alternatively, the LED system may have only a single LED. In particular, the contacting of the LED and the contacting of one or more embedded components according to the embodiments of FIGS. 1A to 2B may be formed.

Reference sign list

1 multi-LED system

2 carriers

3 LEDs

3 'LED

3 '' LED

4 main body

5 first upper metallization 5 'first upper metallization

6 second upper metallization 6 'second upper metallization

7 first lower metallization

7 'first lower metallization 8 second lower metallization

8 'second lower metallization

9 gap

10 gap

11 ESD protection component

11 'ESD protection component

11 "ESD protection component

12 temperature sensor

13 first via 13 'first via 14 second via

14 'second via

15 third via 15 'third via

16 fourth via 16 'fourth via

17 metallic structure

17 'metallic structure

17 '' metallic structure first via 'first via

Claims

claims

1. Multi-LED system,

comprising a support (2) and a plurality of light-emitting diodes (3, 3 '3' ') which are arranged on the support (2), wherein the support (2) has a base body (4), wherein in

Base body (4) a plurality of electrical components (11, 11 '11' ', 12) are embedded.

2. Multi-LED system according to claim 1,

wherein the carrier (2) has upper metallizations (5, 5 '6, 6') for connecting at least one of the embedded components (11, 11 '11' ', 12) and lower metallizations (7, 7' 8, 8 ') to the Connection of the embedded device (11, 11 '11' ', 12), wherein the upper metallizations (5, 5' 6, 6 ') on an upper side and the lower metallizations (7, 7' 8, 8 ') on a Underside of the base body (4) are arranged, wherein the embedded component (11, 11 '11' ', 12) with the upper metallizations (5, 5' 6, 6 ') through vias (15, 15') is connected and wherein the upper metallizations (5, 5 '6, 6') are connected to the lower metallizations (7, 7 '8, 8') by plated-through holes (16, 16 ').

3. Multi-LED system according to one of the preceding claims, wherein the base body (4) is a resin and / or

Polymer material has.

4. Multi-LED system according to one of the preceding claims, wherein in the base body (4) at least one metallic

Structure (17, 17 '17'') is arranged in the form of a block or strip for reducing the thermal resistance.

5. Multi-LED system according to claim 4,

in which a first LED (3) with a first

Through connection (18 ') and a second LED (3' ') with a second through-connection (18') is connected, wherein the through-contacts (18 ') share a metallic structure (17).

6. Multi-LED system according to one of the preceding claims, which has exactly four light-emitting diodes (3, 3 ', 3' ').

7. Multi-LED system according to one of the preceding claims, wherein the embedded electrical components (11, 11 '11' ', 12) comprise at least one temperature sensor (12).

8. Multi-LED system according to one of the preceding claims, wherein the embedded electrical components (11, 11 '11' ', 12) comprise at least one ESD protection component (11, 11' 11 '').

9. Multi-LED system according to one of the preceding claims, comprising upper metallizations (5, 5 '6, 6'), which are arranged on an upper side of the base body (4), wherein the upper metallizations (5, 5 '6, 6 ') first upper one

Metallisations (5, 5 ') for contacting the LEDs (3, 3' 3 '') and second upper metallizations (6, 6 ') for

Further contacting an embedded device (12).

10. Multi-LED system according to claim 9,

the second upper metallizations (6, 6 ')

strip-shaped between the first upper metallizations (5, 5 ') extend.

11. Multi-LED system according to one of claims 9 or 10, wherein the second upper metallizations (6, 6 ') for

Weitererkontaktierung a temperature sensor (12) are formed.

12. Multi-LED system according to one of the preceding claims, comprising lower metallizations (7, 7 '8, 8') which are arranged on an underside of the base body (4), wherein the lower metallizations (7, 7 '8, 8 ') comprise first lower metallizations (7, 7') for connecting the LEDs (3, 3 ', 3' ') and second lower metallizations (8, 8') for connection of an embedded component (12).

13. Multi-LED system according to claim 12,

wherein the second lower metallizations (6, 6 ') are arranged only in lateral edge regions on the underside of the carrier (2).

14. Multi-LED system according to claim 13,

wherein the embedded component (12) is arranged in the top view in a central region of the multi-LED system (1).

15. Multi-LED system according to one of claims 12 or 13, wherein the second lower metallizations (8, 8 ') for

Connection of a temperature sensor (12) are formed.

16. Multi-LED system according to one of claims 12 to 15, wherein the first upper metallizations (5, 5 ') with the first lower metallizations (7, 7') via the first

Vias (5, 5 '13, 13' 18, 18 ') are connected.

A multi-LED system according to any one of claims 12 to 16, wherein an embedded device (12) is connected to the second upper metallizations (6, 6 ') by second vias (15, 15') and wherein the second upper metallizations (6, 6 ') with the second lower

Metallizations (8, 8 ') via fourth vias (16, 16') are connected.

18. carrier for a multi-LED system,

wherein the carrier (2) for the arrangement of a plurality of LEDs (3, 3 ', 3' ') is formed and a base body (4) comprising a resin and / or polymer material, wherein in the base body (4) has a plurality of ESD protection components 11, 11 '11' ') and

at least one temperature sensor (12) are embedded.

19. LED system,

comprising a carrier (2) and one or more light-emitting diodes (3, 3 ', 3' ') which are arranged on the carrier (2), wherein the carrier (2) has a base body (4), wherein in

Basic body (4) one or more electrical components (11, 11 '11' ', 12) are embedded, wherein the carrier (2)

at least one upper metallization (5, 5 '6, 6') for

Connection of at least one of the embedded components (11,

11 ', 11 "12) and at least one lower metallization (7,

7 '8, 8') for connection of the embedded component (11,

11 ', 11' '12), wherein the upper metallization (5,

5 '6, 6') on an upper side and the lower metallization

(7, 7 '8, 8') on an underside of the base body (4) is arranged, wherein the embedded component (11, 11 '

11 '' 12) is connected to the upper metallization (5, 5 '6, 6') by a via (15, 15 ') and wherein the upper metallization (5, 5' 6, 6 ') is connected to the lower one Metallization (7, 7 '8, 8') through a via (16, 16 ') is connected.