EP3308406A1

EP3308406A1 - Led module

Info

Publication number: EP3308406A1
Application number: EP16729750.6A
Authority: EP
Inventors: Robert HÖBER-NEUHOLD; Clemens Mayer; Peter Pachler; Georg PARTEDER; Florian Wimmer
Original assignee: Tridonic Jennersdorf GmbH
Current assignee: Tridonic GmbH and Co KG
Priority date: 2015-06-15
Filing date: 2016-05-20
Publication date: 2018-04-18
Also published as: DE202015103126U1; WO2016201463A1; US20180158992A1; CN107690715B; CN107690715A

Abstract

The invention relates to a method for producing an LED module (1) and comprises at least the following steps: - providing at least one LED chip (4) on a substrate material (2), and - dispensing a not-cured (flowable/liquid) potting compound (3) on top of the LED chip (4), said potting compound (3) containing at least one type of luminescent particles and preferably a matrix material. During the step of dispensing, a predetermined potential is applied directly or indirectly to at least one LED chip (4).

Description

LED module l. Field of the invention

The present invention relates to an LED module (light-emitting diode module) for emitting mixed light, preferably white light. Furthermore, the present invention relates to a lighting device with at least one such LED module.

2. Background

LED modules which are suitable for emitting mixed light, in particular white light, are known from the prior art. The mixed light is produced by mixing a spectrum of one or more LEDs with the emission spectrum of at least one phosphor excited by the LED (s), the emission spectrum of at least one phosphor differing from the spectrum of at least one LED.

As a rule, these LED modules have at least one light-emitting light field, which is usually formed by coating a plurality of LEDs with a potting compound or other covering containing at least one phosphor. From the document DE 20 2014 103 029 Ui, for example, LED modules with light fields are known which comprise differently designed areal areas for emitting different light spectra. These areal areas are separated in each case by dams or partitions of the other areal areas. In each separated by the dams areas LED chips or LED strands are arranged. In the production of these flat areas are covered with a potting compound containing phosphor particles. After filling the areal areas with the potting compound, these luminescent particles sink in the potting compound and deposit on and around the LED chips. The casting compound or the casting compounds may comprise different phosphor particles or different phosphor particle mixtures, so that the two-dimensional regions can emit corresponding light spectra, in order for example to be able to provide a desired mixed light through the LED module. Such a manufacturing method is also referred to as a so-called "_dam-and-ZZ" method. "It has now been found that, in particular with such LED modules produced by a" dam-and-ZZ "method, a certain extent over the beam angle Inhomogeneous light emission can occur, especially if a

comparatively high proportion of phosphor particles were introduced into the potting compound, for example in order to provide a high luminance by the LED module can. Such an inhomogeneous light output could also be found in general in LED modules in which a potting compound is applied, in which phosphor particles still within the

Matrix material (for example, epoxy or silicone-based) can move.

In the light of this prior art, it is an object of the present invention to provide an LED module and a lighting device, with a more homogeneous light output, especially in LED modules with high

Phosphor particle density, can be provided.

These and other objects, which will become apparent upon reading the following description or which will be recognized by those skilled in the art, are achieved by the subject-matter of the independent claims. The dependent claims further form the central idea of the present invention in a particularly advantageous manner.

3. Detailed description of the invention

An LED module according to the invention can be produced by a method which has at least the following steps:

Providing at least one LED chip on a carrier material,

Dispensing uncured (flowable / liquid) potting compound over the LED chip,

wherein the potting compound contains at least one type of phosphor particles, and preferably a matrix material,

wherein a predetermined potential is applied directly or indirectly to at least one LED chip during the dispensing operation.

In a preferred embodiment, the LED module can be produced by a method, wherein the carrier material is formed by a module plate having preferably at least one dam that delimits at least one light field, wherein at least one LED chip is arranged within the light field. A solution according to the invention for applying a predetermined potential to at least one LED chip may be that the electrical connections of the at least one LED chip are short-circuited while the phosphor particles in the liquid potting compound are sinking. Preferably, additionally or alternatively, the electrical connections of the at least one LED chip can be grounded, ie connected to a ground terminal, for example to a ground terminal.

By a Kurzsehl uss of the electrical connections of the LED chip or the LED chips can thus be applied to the terminals of an LED chip, the same potential for all connections of an LED chip, so possibly existing

Charge carriers and thus any existing undetermined potential on one of the LED chips or parts thereof are degraded.

In addition, by connecting the terminals of an LED chip to ground, the potential of the LED chips can be brought to zero, and thus it can be avoided that there is a potential difference to the surroundings of the LED chip or parts of the dispensing device.

The application of a predetermined potential to at least one LED chip can also take place, for example, by applying an alternating voltage to the electrical connections of the at least one LED chip, while the phosphor particles sink in the liquid potting compound. The voltage and the frequency of the alternating voltage can be selected such that the phosphor particles sink substantially linearly in the liquid potting compound.

Another solution to achieve a more homogeneous distribution of

Phosphor particles within the potting compound, is that an AC voltage is applied to the LED chip or to the LED chips as a predetermined potential, and thus changing electrical potentials are constructed so that a deflection of the positively charged phosphor particles avoided or im

Can be substantially avoided. The voltage and the frequency of the

In this case, alternating voltage can be adapted in a simple manner such that the phosphor particles can sink substantially linearly, ie as distraction-free and rectilinearly as possible in the still-liquid potting compound, and thus can be arranged homogeneously on and around the LED chip or the LED chips. The application of a predetermined potential to at least one LED chip, for example, by dropping a DC voltage to the electrical terminals of the at least one LED chip while the phosphor particles in the liquid potting compound drop to deflect the phosphor particles at least partially in the direction of the LED chips.

By applying a DC voltage as a predetermined potential, an electric field can be purposefully provided by the LED chip, so that the sinking movement of the charged phosphor particles can be purposefully influenced, for example in order to be able to guide the phosphor particles to the lateral areas of the LED chips.

Providing at least one LED chip on a carrier material, dispensing an uncured (flowable / liquid) potting compound over the LED chip,

wherein the potting compound contains at least one matrix material and at least one type of phosphor particles,

wherein during the dispensing process at least the region of the potting compound is shielded from light in the region of the excitation spectrum of the phosphor particles.

In the context of the present invention, it has been found that the above-mentioned inhomogeneous light output is based on an inhomogeneous distribution of the phosphor particles within the potting compound, whereby this inhomogeneity is greatest, especially in the area of the LED chips. It was also found that this inhomogeneity is more pronounced in LED chips with a comparatively high density of phosphor particles.

Investigations also showed that the

Fluorescent particles positively charge during the mixing process in the potting compound, and that the LED chips due to the ambient light and the associated photoelectric effect build an electrical potential and thus an electric field between the electrodes. This electric field between the electrodes of the LED chip leads to the deflection of the electrically positively charged phosphor particles during the sinking process and thus leads to an inhomogeneous distribution of the phosphor particles. The present invention now provides several solutions, preferably by indirect or direct Applying a predetermined potential, this deflection of the phosphor particles during the Absinkprozesses within the potting compound can be reduced or avoided.

A solution can be provided by the fact that the LED chips are darkened at least during the Absinkvorgangs so that no or only a significantly reduced photoelectric effect occurs, so that no or a significantly reduced deflection of the positively charged phosphor particles occurs. Such a darkening is thus a form of indirect application of a predetermined potential to the LED chips. Such a darkening can for example take place in that only the LED chips are covered during the sinking process or that substantially the entire LED module is covered. This can be done for example by a dark or black foil, which after the

Dispensen the potting compound on the LED chips or on the LED module is arranged. Such darkening can also be provided by arranging the LED module in a dark environment (for example in a dark room or in a darkened drying duct) at least during the sinking of the phosphor particles.

It is also possible not completely darken the LED chips or the LED module, but only to darken so that only or substantially only light can still hit the LED chips, the no or only a small photoelectric Effect leads. In other words, in this case, the LED chips are illuminated only with light that is outside of the (main) absorption spectrum of the LED chips, Such quasi-selective illumination may be provided by corresponding lights in the corresponding ones

Production areas are provided. Furthermore, it is also possible to use a cover film, which provides a corresponding filter function.

The above suggestions for darkening the LED chips or the LED module can be made only during the Absinkprozesses or during further manufacturing steps or during the entire manufacturing process.

LED modules made by the different solutions proposed here have one compared to the known LED modules more homogeneous phosphor particle distribution, resulting in a more homogeneous light output.

In a particularly preferred embodiment, the LED module can be produced by a method which has at least the following steps:

Providing a module plate, preferably with at least one dam that delimits at least one light field, wherein at least one LED chip is arranged within the light field;

Dispensing a liquid potting compound on the LED chip, wherein the potting compound comprises phosphor particles; and

- Dimming the at least one LED chip such that at least in

Absorption spectrum of the LED chip no light reaches the at least one LED chip at least during the sinking of the phosphor particles in the liquid potting compound.

The present invention is not limited to LED modules that include dams, but generally relates to LED modules in which a potting compound is applied (dispersed) in which phosphor particles can still move within the matrix material (for example, epoxy or silicone-based) ,

Another LED module according to the invention is produced by a method comprising at least the following steps:

- Providing a module plate preferably with at least one dam, which limits at least one light field, wherein within the light field at least one LED chip is arranged;

Dispensing a liquid potting compound on the LED chip, wherein the potting compound comprises phosphor particles;

indirectly or directly applying a predetermined potential to the LED chips by arranging the LED module within a magnetic field while the phosphor particles in the liquid potting compound are decreasing, the orientation and the magnetic field strength of the magnetic field being selected such that the

Phosphor particles fall substantially linearly in the liquid potting compound. Another solution to achieve a more homogeneous distribution of

Phosphor particles within the potting compound, it consists of the LED module at least during the sinking of the phosphor particles within a

(Compensatory) magnetic field to arrange. By such a magnetic field and thus applying a predetermined potential to the LED chips, the occurring Deflection forces due to the electrical potential between the electrodes of the LED chip or the LED chips are quasi compensated, so that the phosphor particles can substantially drop distraction-free and can attach to and around the LED chip. Depending on the charge of the phosphor particles and depending on how high the electric potential between the electrodes of the LED chip is, is

Adjust the orientation and the magnetic field strength of the magnetic field accordingly to allow a substantially linear decrease of the phosphor particles.

- wherein the LED module at least during the sinking of

Phosphor particles in the potting compound is arranged obliquely to the horizontal, that the phosphor particles are substantially linear in the liquid

Sinking potting compound.

Another solution to achieve a more homogeneous distribution of

Phosphor particles within the potting compound, it is the LED module at least during the descent of the phosphor particles to arrange obliquely to horizontal, so that the occurring deflection of the phosphor particles can be compensated by gravity as possible and the phosphor particles in turn can fall as straight as possible in the still liquid potting compound. Depending on the charge of the phosphor particles and depending on how high the electric potential between the electrodes of the LED chip is, the angle of the

Adjusting the tilt of the LED module during the sinking of the phosphor particles accordingly to a substantially linear drop of the

To allow phosphor particles. Another LED module according to the invention is produced by a method comprising at least the following steps:

Providing a module plate, preferably with at least one dam that delimits at least one light field, wherein at least one LED chip is arranged within the light field; Dispensing a liquid potting compound on the LED chip, wherein the potting compound comprises phosphor particles;

wherein the LED module at least during the sinking of the

Phosphor particles in the potting compound is accelerated such that the most homogeneous possible distribution of the phosphor particles is provided at least to the region of the at least one LED chip.

By such an acceleration of the LED module, one of the deflections due to the positive charge of the phosphor particles and the electrical potential between the electrodes of the LED chip or the LED chips opposite force can be generated, which leads to a more homogeneous distribution of the phosphor particles.

Such an acceleration can be achieved, for example, by oscillating the LED module during the sinking of the phosphor particles in the potting compound, such that the LED module, during the sinking, of the

Phosphor particles in the potting compound is continuously moved on a 3-dimensional path, or by the fact that the LED module during the sinking of the phosphor particles in the potting compound is moved at least once jerky.

wherein after the decrease of the phosphor particles in the liquid

Potting a directional flow is generated in order to provide the most homogeneous possible distribution of the phosphor particles at least around the area of the at least one LED chip.

Such a directed flow can be generated, for example, by a stirring device arranged in the liquid potting compound, for example a micro-stirrer. By such a flow, the deflection during the sinking and the associated inhomogeneous distribution of the

Phosphor particles are removed again. Another LED module according to the invention is produced by a method comprising at least the following steps:

wherein during the sinking of the phosphor particles in the liquid potting compound, the LED module by directly applying a predetermined

Potentials is operated at intervals so that the potting compound hardens in layers due to the light output.

By such a layer-wise curing of the potting compound during the sinking of the phosphor particles, an otherwise occurring further deflection of the phosphor particles can be prevented and a more homogeneous

Fluorescent particle distribution can be achieved. In other words, by the intermittent application of a Vorsorgungsspannung to the operation of the LED module and the LED chips contained and thus by interval operation of the LED module and the resulting layered curing of the

Potting the phosphor particles while sinking in a desired (not yet substantially deflected) position virtually frozen. However, the potting compound does not have to harden completely, but only become so strong that further movement (deflection) of the phosphor particles in the hardened layer is prevented or substantially prevented.

Spreading phosphor particles on the at least one light field;

Dispensing a liquid potting compound on the LED chip.

For example, the phosphor particles can be embedded in a liquid matrix prior to sifting, so that they are screened on virtually wet, or also screened onto the at least one light field as (preferably dry) phosphor powder. By sifting the phosphor particles before filling the Lichtfelds with liquid potting compound, the step of sinking the

Phosphor particles and the associated deflection of the phosphor particles are avoided, so that a more homogeneous distribution of the phosphor particles on and around the LED chip or the LED chips can be provided. Another LED module according to the invention is produced by a method comprising at least the following steps:

Applying phosphor particles to the at least one light field by means of a spray coating step;

Dispensing a liquid potting compound on the LED chip.

Instead of sifting the phosphor particles is also a

Spray method for providing a more homogeneous distribution of

Fluorescent particles on and around the LED chip or the LED chips. Again, the step of sinking the phosphor particles can be avoided, so that here a more homogeneous distribution of the phosphor particles can be provided.

Another LED module according to the invention comprises at least:

a module plate preferably having at least one dam that delimits at least one light field, wherein within the light field at least two linearly arranged LED strands each having a plurality of LED chips connected in series is provided; and where

the LED strings with alternating polarities in the at least one

Light field are arranged. When using LED strings which comprise a plurality of series-connected LED chips, the electric potential correspondingly increases due to the photoelectric effect. This effect can at least be reduced if the LED strings are arranged with alternating polarities in such a way that their electric fields at least partially cancel each other out. To the individual LED strands and thus the plurality of series-connected LED chips can preferably be applied directly or indirectly, a predetermined potential, for example a

DC voltage or an AC voltage. Another LED module according to the invention comprises at least:

a module plate preferably having at least one dam that delimits at least one light field, wherein a plurality of LED chips is provided within the light field; and where

the LED chips are arranged in alternating polarity with each other in the at least one light field.

Furthermore, the deflection of the phosphor particles due to the electric fields of the LED chips can be at least reduced if the LED chips are arranged in the light field with alternating polarities to each other that at least partially cancel their electric fields. In this case, for example, a plurality of LED chips arranged in a row or a column can each be arranged with alternating polarity, so that their electrical fields cancel each other at least partially.

Preferably, those used in an LED module according to the invention

Phosphor particles of inorganic phosphor particles, for example, ZnS, ZnSe, CdS, CdSe, ZnTe, CdTe, (Ca ₃ Sc ₂ Si ₃ 0 _12: Ce3 +), Ortho-silicates (BOSE), garnets (YAG: Ce3 ^+, (YGd) AG: Ce3 ⁺ , LuAG: Ce3 ⁺ ), oxides (CaSc0 ₂ : Eu ²⁺ ), SiALONs (a-SiALON: Eu ²⁺ , b-SiALON: Eu ²⁺ ), nitrides (LagSieNn: Ce3 ⁺ , CaAlSiN ₃ : Ce3 ⁺ ) , oxy-nitride (SrSi ₂ N ₂ 0 _2: Eu ^2+, (Ca, Sr, Ba) Si ₂ N ₂ 0 _2: Eu ^2+). In general, any substances / particles which are excitable by light that can be emitted by the LED chips used and then emit a secondary light spectrum can be used as phosphors.

Advantageously, the potting compound used in an LED module according to the invention is a potting compound based on silicone and / or epoxy, which is completely transparent in the spectral regions important for the function, preferably already in the liquid and preferably at least in the crosslinked state. The potting compound may further comprise scattering particles for more homogeneous mixing of light.

Advantageously, in the present invention preferably used dam or have the dams used (if the LED module several

Light fields to have) seen in plan view width between 50 μπι and 2 mm, preferably between 100 μπι and 1 mm and more preferably between 300 and 800 μπι. Such a dam or a dam structure can either be formed directly on the module plate, for example by the application and curing of a suitable material (for example by a Dispensing method) or initially produced as a separate component, which is then connected to the module plate.

The invention also relates to a method for producing an LED module which has at least the following steps:

Finally, the present invention relates to a lighting device comprising at least one of the LED modules described above.

4. Description of preferred embodiments

Hereinafter, a detailed description of the figures will be given. It shows:

Figure 1 is a schematic view of a first embodiment of an LED module according to the invention during the manufacturing process;

Figure 2 is a schematic view of a second embodiment of an LED module according to the invention during the manufacturing process;

Figure 3 is a schematic view of a third embodiment of an LED module according to the invention during the manufacturing process; and

Figure 4 is a schematic view of a fourth embodiment of an LED module according to the invention during the manufacturing process.

Hereinafter, a preferred embodiment of an LED module 1, together with the respectively particularly preferred manufacturing method of such an LED module 1 with reference to Figures 1 to 3 will be explained.

In a first step, a module plate 2 with (at least) a dam 3, which preferably delimits a substantially circular light field, is provided. Within the light field, a plurality of LED chips 4 is arranged. For the sake of clarity, in the figures, in each case only one LED chip has an associated reference number. The LED chips 4 are particularly preferably arranged in rows and columns in the light field, so that a substantially homogeneous distribution of LED chips 4 on the light field can be achieved. As an alternative to the circular dam 3 shown, it is also possible to provide a plurality of interconnected or separately arranged dams on the module plate 2.

Preferably, the dam 3 has a seen in plan view width between 50 μπι and 2 mm. The dam 3 can either be formed directly on the module plate 2 or initially produced as a separate component, which is then connected to the module plate 2.

As LED chips 4, depending on the application, blue-luminescent, red-luminescent, green-luminescent, yellow-luminescent, UV-bright LED chips or a mixture thereof can be used. In a further step, a flowable potting compound 5 is introduced into the light field (or into the light fields), the potting compound 5 being mixed with phosphor particles (distributed as homogeneously as possible therein). As far as several light fields are provided, of course, different potting compounds with different phosphor particles or different

Fluorescent particle mixtures are used. The liquid or flowable

Potting compound 5, preferably a potting compound based on silicone and / or epoxy, is preferably applied by means of a dispensing method. After the filling of the light field with the flowable potting compound 5, the phosphor particles mixed into them start due to the force of gravity within the potting compound

Casting 5 drop and deposit on and around the LED chips 4.

As already stated above, the phosphor particles are charged during the process

Mixing process in the potting compound so that it can be deflected during the sinking in the potting compound by an electric field that can build up between the electrodes of the LED chips due to the photoelectric effect. As a result, a certain

Severance effect occur, leading to an inhomogeneous distribution of

Phosphor particles and thus can lead to an inhomogeneous light output of the LED module. In the figures 1 to 4 are now particularly preferred, different

Solutions have shown that can reduce or prevent such a segregation effect.

A solution shown in FIG. 1 can be provided in that at least the LED chips 4 are darkened during the sinking process so that no or only a significantly reduced photoelectric effect occurs, so that no or a significantly reduced deflection of the positively charged phosphor particles occurs. Such a darkening is thus a form of indirect application of a predetermined potential to the LED chips 4. Such a darkening can be effected, for example, by a film 6 (preferably a dark or black) arranged on the LED module 1. The film 6 is thereby arranged after filling with the potting compound 5 on the LED module 1, that at least the LED chips 4 are covered and thus darkened. The film 6 may be formed such that no more light can get to the LED chips 4 or only light that is outside the (main) absorption spectrum of the LED chips 4, so that no more photoelectric effect occurs or this can be significantly reduced.

Furthermore, as shown in FIG. 2, it is possible for the LED module 1, at least while the phosphor particles in the potting compound 5 are sinking, to be arranged within a darkened environment, for example within a darkened channel 10. Instead of such a darkened channel 10 can also

Manufacturing or individual steps of the production in a darkened environment done or illuminated only with light that emits light that is outside the (main) absorption spectrum of the LED chips 4, so that no more photoelectric effect occurs or this considerably can be reduced. Such production in a correspondingly darkened environment is thus a form of indirect application of a predetermined potential to the LED chips 4.

In Figure 3 is another way to reduce said

Severance effect shown. As can be clearly seen in Figure 3, in this solution, the LED module 1 at least while the phosphor particles in the

Sealing compound 5 sink inclined to the horizontal, so that the occurring deflection of the phosphor particles can be compensated by gravity as possible and the phosphor particles turn as straight as possible in the still Grout 5 can fall. Depending on the charge of the phosphor particles and depending on how high the electrical potential between the electrodes of the LED chip, the angle of inclination of the LED module during the sinking of the phosphor particles is adjusted accordingly to allow a substantially linear decrease of the phosphor particles.

The LED module 1 of Fig. 4 includes one or - as shown - a plurality of LED chips 4, which can be operated to emit light. For example, the LED chips 4 may be configured to emit blue light during operation. But it is also possible to install different types of LED chips 4 in the LED module 1, which emit light of different colors or wavelengths. The LED chips 4 are mounted on a support 2, for example a printed circuit board such as a PCB. Preferably, a surface of the carrier 2, on which the LED chips 4 are applied, is reflective. Preferably, the LED chips 4 are contacted in the LED module 1 in series with bonding wires 7. Each LED chip 4 is preferably connected with at least two bonding wires 7. About the bonding wires 7, the LED chips 4 for the operation of the LED module 1 can be supplied with voltage and controlled. During the manufacturing process 100 of the LED module 1, it is possible to charge the LED chips via the bonding wires 7 with the second polarity. In the LED module 1, the LED chips 4 are arranged in particular within a dam 3. The dam 3 can enclose the LED chips 4 as indicated in FIG. 3 at least partially, for example annularly. For operating the LED module 1, at least two bonding wires 7 are led to the outside of the dam 3 to at least two bonding pads 8. The bond pads 8 can also be connected directly or indirectly to an operating voltage source.

Within the dam 3, the LED chips 4 are embedded in a matrix material, for example a silicone matrix. The LED module 1 is therefore preferably produced by means of the dam and fill technique The matrix material is preferably fully transparent to the light from the LED chips 4 and protects the LED chips 4 and their coatings Furthermore, color conversion particles 3 are provided in the matrix material

Color conversion particles 3 are in particular on the carrier second

opposite surfaces and on the side surfaces of the LED chips 4 each with uniform thickness deposited. This is through the above

inventive method 100 achievable.

The color conversion particles 3 can be, for example, phosphors which at least partially convert the light of the LED chips 4 in their wavelength. If the LED chips 4 emit, for example, in the blue spectral range, then

for example, by a radiating in the yellow spectral range

Color conversion material for the color conversion particles 3 total of the LED module 1 white light are generated. By an appropriate choice of

Color conversion material of the color conversion particles 3 and Art

(Emission wavelength) of the LED chips 4 are different colors and

Color mixtures of the light emitted by the LED module 1 can be generated.

It can also be seen in FIG. 3 that no color conversion particles 3 are deposited on the surface of the carrier 2 in the LED module 1 between the LED chips 4. The color conversion particles 3 are deposited in particular only on and laterally on the LED chips 4. As a result, the carrier surface is exposed between the LED chips 4 and, at least there, is preferably designed to be reflective in order to support and optimize the light extraction from the LED module 1. As indicated in Fig. 3 by the arrows occurs in the operation of the LED module 1 light from each of the LED chips 4 and then happens regardless of its beam angle, an approximately equal thickness layer of color conversion particles 3. This ensures that of each LED chip 4 a very uniform, in particular the same color light is emitted. Thus, overall, the uniformity of the light output by the LED module 1 during operation, in particular its color homogeneity, is significantly improved over the emission angle. It is also pointed out that color conversion particles 3 can also be deposited on the bonding wires 5 which connect the LED chips 4 of the LED module 1 to one another. The bonding wires 7 are sometimes even from

Color conversion particles 3 wrapped.

To produce the color conversion coating of the LED chips 4, first the color conversion particles 3, preferably mixed in and with the

Matrix material, dosed between the dam 3 and the LED chips 4. A viscosity of the matrix material is preferably chosen such that the color conversion particles 3 can be distributed in the matrix material and migrate therein. Conventionally, a branching process of the

Color conversion particles 3 begin at which the color conversion particles 3 would be deposited purely gravity driven on the surfaces of the LED chips 4 and the support 2 before the matrix material is cured. According to the invention, however, this branching process is assisted or at least influenced by the application of a predetermined potential to the LED chips 4. The application of a predetermined potential to the LED chips can be done by applying a corresponding voltage such as a DC or AC voltage to the LED chips 1. This means that at least one defined electric field arises between the LED chips 4 and the

Color conversion particles 3.

In addition, a predetermined potential can also be applied to the carrier 2. This can be done by applying a voltage to the carrier 2. As a result, for example, falling color conversion particles 3 can be prevented from depositing on the upper side of the carrier 2. In particular, the

Color conversion particles 3 repelled from the carrier top, so that the

Coating the side surfaces of the LED chips 4 is further supported and is achieved in particular that the layer on the top and on the side surfaces of the LED chips 4 of uniform thickness. In addition, it is favored that the color conversion particles 3 are displaced from the top of the carrier 2 between the LED chips 4 and between the outermost LED chips 4 and the dam 3 wholly or far. These color conversion particles 3 are then forced toward the side surfaces of the LED chips 4 and are deposited there due to the applied

Voltage on. As a result, the spaces on the carrier top remain largely free of color conversion particles 3 and preferably form

reflective surfaces.

For example, the predetermined potential can be applied by voltage U + generated by a voltage source 9. A voltage U + generated by preferably the same voltage source 9 is applied to the LED chips 4 via the bond pads 8 and the bonding wires 7. Due to the voltage U + can build on the top of the LED chips 4, an electric field that the charged

Color conversion particles 3 to the LED chips 4 forces out. Thereby, the setting process of the color conversion particles 3 can be accelerated, and the color conversion particles 3 are deposited on the upper surfaces and the side surfaces of the LED chips 4.

The voltage U + across the LED chips 4 may preferably be between 20-100 V, more preferably between 40-80 V, even more preferably at 60 V.

For example, the predetermined potential by shorting the

Bonding pads 8 and thus the LED chips 4 are applied. By short-circuiting the LED chips 4, it is achieved via the bond pads 8 and the bonding wires 7 that the same potential is applied to all LED chips 4 and also to all parts and electrodes of the LED chips 4. Due to the short-circuiting of the LED chips 4, it can be achieved that a uniform electric field can build up on the upper side of the LED chips 4, and that the charged color conversion particles 3 drop uniformly towards the LED chips 4. Thereby, the setting process of the color conversion particles 3 can be influenced and the bearings are stored

Color conversion particles 3 on the upper sides and the side surfaces of the LED chips 4 at. Additionally or alternatively, the electrical connections of the at least one LED chip can be grounded. For example, the bond pads 8 with a

Ground terminal, for example, to be connected to a ground terminal.

The predetermined potential is also formed by a changing applied voltage, whereby over time different applied voltages U + are applied. This means that the electric fields at the LED chips 4 can each be adjusted in a targeted manner, preferably even variable over time. Thereby, a quantity and / or a deposition form of the

Color conversion particles on the tops or side surfaces of the LED chips 4 are fine-adjusted, in particular also slightly inhomogeneous over the course of the top and / or the side surfaces of the LED chips 1. Thus, the

Color homogeneity of the finished manufactured LED module 1 can be further improved. In particular, by suitably setting the voltages U +, it is also possible to perfect the color homogeneity over the emission angle. Incidentally, the carrier 2 could also be directly charged with a voltage in order to charge it. The invention also relates to a method for producing an LED module 1, which has at least the following steps:

Providing at least one LED chip 4 on a carrier material 2, dispensing an uncured (flowable / liquid) potting compound 3 over the LED chip 4,

wherein the potting compound 3 contains at least one type of phosphor particles, and preferably a matrix material,

wherein a predetermined potential is applied to at least one LED chip 4 directly or indirectly during the dispensing operation. By in the particularly preferred embodiments and the above further proposals for reducing or preventing such segregation LED modules can be provided with a more homogeneous compared to the known LED modules phosphor particle distribution, thereby providing a more homogeneous overall light output can.

In particular, the present invention is not limited to LED modules manufactured by a "on-and-Fi ^' ZZ" method, but generally relates to all LED modules to which a potting compound in which phosphor particles are applied The present invention is not limited to the preceding embodiments, as long as it is encompassed by the subject of the following claims: Furthermore, the preceding embodiments can be combined with each other in any desired manner. In particular, the present invention is not limited to the fact that all LED chips arranged in the light field must necessarily be provided with phosphor.

Claims

Protective applications

- Providing at least one LED chip (4) on one

Carrier material (2),

- dispensing an uncured (flowable / liquid)

Potting compound (3) above the LED chip (4),

wherein the potting compound (3) contains at least one type of phosphor particles and preferably a matrix material,

during the dispensing process directly or indirectly

predetermined potential is applied to at least one LED chip (4).

LED module (1) produced by a method according to claim 1, wherein the application of the predetermined potential by shorting the electrical connections of the at least one LED chip (4) takes place while the phosphor particles in the liquid potting compound (5) decrease.

LED module (1) produced by a method according to claim 1, wherein the application of the predetermined potential by applying a

AC voltage to the electrical terminals of the at least one LED chip (4) takes place while the phosphor particles in the liquid

Potting compound (5) fall, wherein preferably the voltage and the frequency of the AC voltage are selected such that the

Phosphor particles fall substantially linearly in the liquid potting compound (5).

DC voltage to the electrical connections of the at least one LED chip (4) takes place while the phosphor particles in the liquid

Potting compound (5) decrease in order to divert the phosphor particles at least partially in the direction of the LED chips (4). A LED module (1) manufactured by a method according to claim 1, wherein the application of the predetermined potential is performed by disposing the LED module (1) within a magnetic field while the

Phosphor particles fall in the liquid potting compound (5), wherein the orientation and the magnetic field strength of the magnetic field are selected such that the phosphor particles are substantially linear in the liquid

Potting compound (5) sink.

An inventive LED module (1) can be produced by a method according to claim 1,

wherein during the dispensing process at least the region of the potting compound (5) is shielded from light in the region of the excitation spectrum of the phosphor particles and thus indirectly a predetermined potential is applied to at least one LED chip (4).

7- LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2), preferably with at least one

Dam (3) which delimits at least one light field, wherein within the light field at least one LED chip (4) is arranged;

- Dispensen a liquid potting compound (5) on the LED chip (4), wherein the potting compound (5) comprises phosphor particles;

- Darkening of the at least one LED chip (4) such that at least in the absorption spectrum of the LED chip (4) no light passes at least during the sinking of the phosphor particles in the liquid potting compound (5) to the at least one LED chip (4) and thus indirectly a predetermined potential is applied to at least one LED chip (4).

LED module (1) according to one of claims 1 or 2, wherein at least during the sinking of the phosphor particles, the entire LED module is darkened.

LED module (1) according to one of the preceding claims, wherein at least during the sinking of the phosphor particles, the LED module (1) is arranged in a darkened environment.

10. LED module (l) according to any one of the preceding claims, wherein at least during the descent of the phosphor particles, the LED module (1) is arranged in an environment which is illuminated by a light source, the visible light outside the absorption spectrum of the LED Chips (4) gives.

11. LED module (1) according to one of the preceding claims, wherein the

at least one LED chip (4) or the LED module (1) at least during the sinking of the phosphor particles by at least in

Absorption spectrum of the LED chip (4) opaque film, preferably a dark or black film (6) is covered.

LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2) preferably with at least one

- wherein the LED module (1) at least during the lowering of the

Phosphor particles in the potting compound (5) is arranged obliquely to the horizontal, that the phosphor particles substantially linearly in the liquid potting compound (5) decrease.

LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2) preferably with at least one

- wherein the LED module (1) at least during the lowering of the

Phosphor particles in the potting compound (5) is accelerated in such a way that the most homogeneous possible distribution of the phosphor particles is provided at least around the region of the at least one LED chip (4). LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2) preferably with at least one

- wherein after the decrease of the phosphor particles in the liquid

Potting compound (5) a directed flow is generated in order to provide the most homogeneous possible distribution of the phosphor particles at least around the region of the at least one LED chip (4),

wherein preferably the flow in the liquid potting compound (5) by a in the liquid potting compound (5) arranged stirring means, in particular a micro-agitator, is generated.

LED module (1) produced by a method according to one of claims 1, 3 or 4,

wherein during the sinking of the phosphor particles in the liquid potting compound (5), the LED module (1) is operated in intervals by applying the predetermined potential at intervals such that the potting compound (5) cures in layers due to the light output.

LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2) preferably with at least one

- Sifting of phosphor particles on the at least one light field;

- Dispensing a liquid potting compound (5) on the LED chip (4).

LED module (1) produced by a method comprising at least the following steps:

- Providing a module plate (2) preferably with at least one

Dam (3) which delimits at least one light field, wherein within the light field at least one LED chip (4) is arranged; Applying phosphor particles to the at least one light field by means of a spray coating step;

Dispensing a liquid potting compound (5) on the LED chip (4). 18. LED module (1) according to one of the preceding claims, further

full:

- A module plate (2) preferably with at least one dam (3) which limits at least one light field, wherein within the light field at least two linearly arranged LED strands, each with a plurality of series connected LED chips (4) is provided; and where

- The LED strands are arranged with alternating polarities in the at least one light field.

19. LED module (1) according to one of the preceding claims, further

full:

- A module plate (2) preferably with at least one dam (3) which limits at least one light field, wherein within the light field, a plurality of LED chips (4) is provided; and where

- The LED chips (4) are arranged in alternating polarity to each other in the at least one light field.

20. LED module (1) according to one of the preceding claims, wherein the

Phosphor particles of inorganic phosphor particles are. 21 LED module (1) according to any one of the preceding claims, wherein the liquid potting compound (5) is a potting compound (5) on silicone and / or epoxy-based and is preferably transparent in the cured state.

22. LED module (1) according to any one of the preceding claims, wherein the liquid potting compounds (5) is applied by a dispensing method.

23. LED module (1) according to one of the preceding claims, wherein the dam (4) has a seen in plan width between 50 μπι and 2 mm, preferably between 100 μπι and 1 mm and more preferably between 300 μπι and 800 μπι.

24. Lighting device comprising at least one LED module (1) according to one of the preceding claims.

25. A method for producing an LED module (1), comprising at least the following steps:

- Providing at least one LED chip (4) on one

Carrier material (2),

Dispensing an uncured (flowable / liquid) potting compound (3) over the LED chip (4),

wherein a predetermined potential is applied directly or indirectly to at least one LED chip (4) during the dispensing operation.