WO2019048415A1

WO2019048415A1 - Led, use of an led, method for operating an led, and method for producing an led

Info

Publication number: WO2019048415A1
Application number: PCT/EP2018/073704
Authority: WO
Inventors: Ivar TÅNGRING; Ion Stoll
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2017-09-07
Filing date: 2018-09-04
Publication date: 2019-03-14
Also published as: DE102017120642A1

Abstract

An LED (100) has an optoelectronic semiconductor chip (1) and a converter element (2). The semiconductor chip and the converter element are designed such that, when operated as intended, the semiconductor chip emits first radiation. The converter element converts some of the first radiation emitted by the semiconductor chip into second radiation. The LED emits mixed radiation consisting of the unconverted first radiation and the second radiation. The mixed radiation has a spectrum having a first and a second local intensity maximum. The first intensity lies within a first spectral range (31) between 630 nm and 690 nm inclusive, and the second intensity maximum lies within a second spectral range (32) between 700 nm and 760 nm inclusive. The proportion of the mixed radiation within the second spectral range is at least 10% and at most 40% of the proportion of the mixed radiation within the first spectral range.

Description

description

LUMINOUS DIODE, USE OF AN INDICATOR, METHOD OF OPERATING AN ILLUMINATED DIODE AND METHOD FOR PRODUCING AN ILLUMINATED DIODE

A light-emitting diode is specified. In addition, a use of a light emitting diode, a method for

Operating a light emitting diode and a method for producing a light emitting diode specified.

One problem to be solved is to have a compact

Specify LED that can be used for plant breeding. Other objects to be solved are to use such a light emitting diode, a method for

To operate such a light emitting diode and to provide a method for producing such a light emitting diode.

These objects are achieved by the subject matter and method of the independent claims as well as by the use and method of claims 14 and 15.

Advantageous developments and refinements are

Subject of the dependent claims. In accordance with at least one embodiment, the light-emitting diode has an optoelectronic semiconductor chip and a

Converter element on. Preferably, the light emitting diode comprises only a single optoelectronic semiconductor chip. The semiconductor chip comprises a semiconductor layer sequence with an active layer for generating electromagnetic radiation. The semiconductor layer sequence is based, for example, on a III-V compound semiconductor material. In which Semiconductor material is, for example, a

Nitride compound semiconductor material such as Al _n _In] __ _ _n _m _m N Ga, or a phosphide compound semiconductor material, such as

In Al _{_n]} __ _n _ _m _m P Ga, or an arsenide compound semiconductor material such as Al _n _In] __ _n _ _m _m Ga As, or

Al _n In _] __ _n _ _m Ga _m AsP, where each 0 ^ n <1, 0 ^ m <1 and m + n <1. In this case, the semiconductor layer sequence

Have dopants and additional components. For the sake of simplicity, however, only the essential ones are

Components of the crystal lattice of the

Semiconductor layer sequence, that is, Al, As, Ga, In, N or P, indicated, although these may be partially replaced by small amounts of other substances and / or supplemented.

The semiconductor layer sequence is preferably based on AlInGaN or AlInGaP.

The semiconductor layer sequence comprises an active layer. The active layer of the semiconductor layer sequence contains in particular at least one pn junction and / or at least one quantum well structure and can, for example, in

intended operation produce electromagnetic radiation in the blue or green or red spectral range or in the UV range. The semiconductor chip preferably comprises one, in particular exactly one, coherent active layer.

A semiconductor chip is understood here and below as a separately manageable and electrically contactable element. A semiconductor chip is produced, in particular, from the singulation of a semiconductor layer sequence which has grown on a growth substrate. A semiconductor chip comprises

prefers exactly one originally contiguous region of the grown semiconductor layer sequence. In particular, a semiconductor chip comprises one, for example exactly one, active layer. The lateral extent of the semiconductor chip, measured parallel to the main extension direction of the active layer, is for example at most 1% or at most 5% greater than the lateral extent of the active layer.

The semiconductor chip is, for example, a so-called flip-chip and / or a

Thin-film semiconductor chip in which the growth substrate for the semiconductor layer sequence is detached. Alternatively, however, the semiconductor chip may also be a volume emitter in which the growth substrate is still present, for example. The

Volume emitter can also be designed as a flip-chip.

The converter element is preferably designed as a coherent or simply continuous layer.

For example, the converter element covers a

Radiation exit surface and side surfaces of the

Semiconductor chips partially or completely. For example, the converter element forms the semiconductor chip in a form-fitting or conforming manner. The converter element can at the

Radiation exit surface and / or the side surfaces

directly adjacent to the semiconductor chip.

In accordance with at least one embodiment, the semiconductor chip is set up such that it emits first radiation during normal operation. Below that of the semiconductor chip

emitted first radiation is understood in particular the radiation which is directly from the active layer of the

Semiconductor chips is generated. The first radiation is therefore inherent radiation of the semiconductor chip. That is, the first radiation itself does not include any components that have already been converted by a converter element. The first radiation is thus unconverted radiation. In accordance with at least one embodiment, this is

Converter element set up so that it is in

intended operation a part of the

Semiconductor chip emitted first radiation in second

Radiation converted. The second radiation is thus understood to mean only the radiation which has been converted or converted by the converter element. The second radiation is different from the first radiation and is

especially red shifted.

According to at least one embodiment, the emits

Light-emitting diode in normal operation Mixed radiation from the remaining, unconverted first radiation and the second radiation. The light emitted by the light-emitting diode during normal operation preferably exists

Mixed radiation exclusively from the unconverted first radiation and the second radiation. According to at least one embodiment, the

Mixed radiation a spectrum with a first local

Intensity maximum and a second local

Intensity maximum on. Among the spectrum here is in particular the

Intensity distribution of the mixed radiation understood as a function of wavelength. A local intensity maximum is in particular the peak of a peak in the spectrum of the mixed radiation. Left and right of the first and second intensity maximum, especially in the range between the first and second intensity maximum, falls

Intensity of the mixed radiation, for example to a value not exceeding 60% or not more than 50% or not more than 30% or at most 20% or at most 10% of the intensity at the location of the first and / or second intensity maximum.

The peaks associated with the local intensity maxima in the

Spectrum, for example, have a half-width (FWHM) of at most 70 nm or at most 50 nm or at most 40 nm or at most 30 nm. For example, the peaks can be fit with a Gaussian or a Breit-Wigner function. In particular, the peaks have a statistical

Significance.

In accordance with at least one embodiment, the first one lies

Intensity maximum in a first spectral range or first wavelength range. The first spectral range is the range between 630 nm and 690 nm inclusive, preferably between and including 650 nm and 670 nm, especially

preferably between 655 nm and 675 nm inclusive.

In accordance with at least one embodiment, the second is

Intensity maximum in a second spectral range or second wavelength range. The second spectral range is the range between 700 nm and 760 nm inclusive, preferably between 720 nm and 740 nm inclusive,

more preferably between 725 nm and 735 nm inclusive.

According to at least one embodiment, the proportion of the mixed radiation in the second spectral range of the total intensity of the mixed radiation is at least 10% or at least 12% or at least 15% or at least 17% of the portion of the mixed radiation in the first spectral range of the total intensity of the mixed radiation. Alternatively or additionally, the lying in the second spectral range Proportion of mixed radiation in the total intensity of the

Mixed radiation at most 40% or at most 35% or at most 30% or at most 27% or at most 25% or at most 23% of the first spectral range

Proportion of mixed radiation in the total intensity of

Mixed radiation.

The proportion of the mixed radiation in the first spectral range is understood here and below to mean the intensity of the mixed radiation integrated over this spectral range.

The same applies to the proportion of mixed radiation in the second spectral range. The total intensity of the mixed radiation is the integrated intensity of the mixed radiation over the entire spectral range.

The proportion of the mixed radiation in the second spectral range is, for example, at least 5% or at least 10% of the total intensity of the mixed radiation. In at least one embodiment, the light-emitting diode has an optoelectronic semiconductor chip and a

Converter element on. The semiconductor chip and the

Converter element are set up in that way

intended operation of the semiconductor chip emits first radiation. The converter element converts a portion of the first radiation emitted by the semiconductor chip into second radiation. The light emitting diode emits mixed radiation from the unconverted first radiation and the second

Radiation. The mixed radiation has a spectrum with a first and a second local intensity maximum. The first intensity maximum lies in a first

Spectral range between 630 nm and 690 nm inclusive, the second intensity maximum lies in a second Spectral range between 700 nm and 760 nm inclusive. The proportion of the second spectral range of the

Mixed radiation at the total intensity of the mixed radiation is at least 10% and at most 40% of the first

Spectral range lying portion of the mixed radiation in the total intensity of the mixed radiation.

In particular, the present invention is based on the finding that an effective rearing of plants requires illumination of these plants with light from the spectral range of approximately 660 nm and of the spectral range of approximately 730 nm. This so-called "Emerson Enhancement Effect" is probably due to the fact that in a plant two

Photosynthesis processes proceed, with the first

Photosynthesis process especially by light from the

Spectral range around 660 nm and the second

Photosynthesis process especially by light from the

Spectral range is excited by about 730 nm. If both processes are stimulated at the same time, they reinforce each other, which increases the speed of plant growth. It is particularly advantageous if the intensity of the light from the spectral range at about 730 nm makes up about 20% of the intensity of the light from the spectral range at about 660 nm.

In conventional plant irradiation systems, illumination systems are made of multiple LEDs for irradiation

used. For example, a lighting system could

which uses a 730 nm LED for every fifth 660 nm LED. If the lighting systems are to be downsized, fewer LEDs must be used. In a very small lighting system could for

Example two LEDs, a 660 nm LED and a 730 nm LED, be used with the 730 nm LED operating at a lower input power to achieve the desired

Intensity ratio of about 5: 1 to achieve. However, this in turn requires more complicated circuits and is therefore less space-saving and costly.

Advantageously, in the present invention, only a single LED is needed to provide light with the desired

To get red shares. This is made possible in particular by the use of a correspondingly selected converter element. With such a light emitting diode, a particularly compact, in particular only a single LED comprehensive lighting system for efficient plant growth can be realized.

According to at least one embodiment, the

Converter element to a first conversion material or consists thereof. The first conversion material is like this

in that it converts the first radiation predominantly into radiation in the spectral range between 700 nm and 800 nm inclusive, preferably in radiation in the spectral range between 700 nm and 760 nm inclusive.

In particular, the first conversion material comprises all converter particles of the converter element, which predominantly convert into the spectral range between 700 nm and 800 nm.

"Predominantly" means here and below that at least 50% or at least 60% or at least 70% or at least 80% of the radiation or the radiation intensity lies in said wavelength range.

The first conversion material is chosen in particular such that the radiation converted by the first conversion material has an intensity maximum in the region around 730 nm, for example, in the range between 720 nm and 740 nm inclusive.

The first conversion material may be one or more

different substances, in particular several different ones

Having particles or molecules.

For example, the first conversion material comprises organic or organometallic, fluorescent or phosphorescent molecules, such as acridines, acridinones, anthraquinones,

Anthracenes, cyanines, dansyls, squaryllium fluorophors,

Spiropyrane, boron-dipyrromethene (BODIPY), perylenes

(preferably perylenediimides, lumogens), pyrenes, naphthalenes, flavins, pyrroles, porphyrins and their metal complexes,

Diarylmethanes, triarylmethanes, phthalocyanines and the metal complexes of phthalocyanines, quinones, azo dyes,

Indophenols, oxazines, oxazones, thiazines and thiazoles,

Xanthene, fluorenes, flurones, pyronines, rhodamines, coumarins. For organometallic molecules are called metal for

Examples of transition metals, such as Rh, Os, Ru, Ir, Pd and Pt, particularly preferably Ir (III), Os (II), Pt (II), Ru (II),

used. For example, the following organic ligands or ligands derived from the following skeletons may be used: porphyrins, porphines, 2, 2-bipyridines, 2-phenylpyridines, 3- (thiazol-2-yl), 3- (benzothiazol-2-yl), 3 - (imidazol-2-yl), 3- (benzimidazol-2-yl), pyridyl azolates,

Tris [4,7-diphenyl-l, 10-phenanthrolines] ruthenium (II) chloride, iridium (III) bis (2-phenylquinolyl) -2-N, C 2 'acetylacetonate, bis [2- (2'-benzothienyl) - pyridinato-N, C3 '] iridium (acetylacetonate),

Tris (2,5-bis-2'- (9 ', 9'-dihexylfluorenes) pyridines) iridium (III), (btp) 2 Ir (acac), (piq) 3 Ir, (piq) 2 Ir (acac), wherein piq = 1- phenylisoquinolinato, btp = 2- (2'-benzo [4,5-thienyl] pyridinato, acac = acetylacetonate,

Pt (II) tetraphenyltetrabenzoporphyrin,

Pd (I I) tetraphenyltetrabenzoporphyrin,

[Os (btfp) 2 (dppb)], [Os (btfp) 2 (pp2b)], [Os (tfp) 2 (dppb)],

[Os (ibifp) 2 (dppb)], where btfp = 5- (benzothiazol-2-yl) -3-trifluoromethylpyrazoles, dppb = 1,2-bis (diphenylphosphino) -benzenes,

pp2b = 2-bis (phospholano) benzene, tfp = 5- (thiazol-2-yl) -3-trifluoromethylpyrazole, ibifp = 5- (1-isopropylbenzimidazol-2-yl) -3-trifluoromethylpyrazole.

Other possible materials for the first

Conversion material are in the paper "Near-infrared

phosphorescence: materials and applications "by Haifeng

Xiang et al. (Chem. Soc. Rev. 2013, 42, 6128-6185) and in the paper "Review of Long-Wavelength Optical and NIR Imaging Materials: Contrast Agents, Fluorophores, and Multifunctional Nano Carriers" by Vikram Pansare et al (Chem. Mater., 2012, 24 (5), pp 812-827), the disclosure of which is hereby incorporated by reference.

For the first conversion material can also

(nanoparticulate) semiconductor materials and doped

Semiconductor materials are used, such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgTe, HgSe, GaP, GaAs, GaSb, AIP, AlAs, AlSb, InP, InAs, InSb, SiC, InN or their

Mixed crystals (ternary, quaternary, et cetera) One

Combination of several different layers of these materials is also possible. As a semiconductor material serving as a host metal for photon-photon conversion metal ions, in addition to those mentioned above Semiconductor materials can also be used for example GaN, ZnO, SnC> 2, MgS, MgSe, BeTe.

For the first conversion material it is also possible to use inorganic-organic hybrid semiconductors, as described, for example, in the paper "A Family of Highly Efficient Cul-Based Lighting Phosphors Prepared by a Systematic, Bottom-Up Synthetic Approach" by Wei Liu et al. (J. Am. Chem. Soc., 2015, 137 (29), pp 9400-9408), the disclosure content of which and the disclosure content of the references cited in this paper are hereby incorporated by reference.

In accordance with at least one embodiment, the first conversion material comprises a matrix material with therein

embedded converter particles. The converter particles may be particles of the above materials. For example, the matrix material may comprise or consist of one or more of the following materials: polyolefins (eg, high or low density polyethylene (PE) or polypropylene (PP)),

Polyvinyl chloride (PVC), polystyrene (PS), polyester,

Polycarbonate (PC), polyethylene terephthalate (PET),

Polyethersulfone (PES), polyethylene naphthalate (PEN),

Polymethyl methacrylate (PMMA), polyimide (PI), polyether ketones (PEEK), polyamides, polyphthalamides (PPA),

Polycyclohexylenedimethylene terephthalate (PCT), silicones, epoxies or a liquid crystalline polymer (liquid

crystalline polymer - LCP).

The matrix material may additionally be treated with a polymeric

Moisture and / or gas barrier be provided. The concentration of converter particles in the

For example, matrix material is in the range of between 0.001 g / l and 0.1 g / l or between

including 0.002 mol / kg and 0.2 mol / kg. Such regions are particularly advantageous in the case of an optical path through the first conversion material of approximately 1.5 mm, for example with an optical path of between 1 mm and 2 mm.

According to at least one embodiment, the first one

Conversion material in the form of a layer on and / or arranged laterally next to the semiconductor chip. In particular, at least 90% or at least 95% of the first is

Conversion material arranged in a layer. These

For example, layer has a constant layer thickness within the manufacturing tolerance. Within the layer is the

Concentration of the first conversion material preferably within the manufacturing tolerance homogeneous.

In accordance with at least one embodiment, the thickness of the layer with the first conversion material is at least 5 μm or at least 10 μm or at least 15 μm or at least 20 μm. Alternatively or additionally, the thickness of the layer with the first conversion material is at most 40 ym or at most 35 ym or at most 30 ym. These thicknesses have the layer with the first conversion material, in particular, when this layer by a sedimentation of the first

Conversion material is generated. It is for the layer with the first conversion material but also larger

Layer thicknesses conceivable, for example between 100 ym and 200 ym inclusive, in particular if the first

Conversion material has not settled by sedimentation. In accordance with at least one embodiment, the light-emitting diode further comprises a carrier. The semiconductor chip and the

Converter element are applied to the carrier. The carrier is preferably designed to be reflective for the first radiation and / or the second radiation and / or the mixed radiation. The reflectance of the carrier for these radiation (s) is for example at least 80% or at least 90%. The carrier is mechanically self-supporting and carries the semiconductor chip and the converter element.

Preferably, the carrier comprises a metallic lead frame. Further, the carrier may comprise a housing body, wherein the leadframe is surrounded with the housing body. The housing body is, for example, electrically insulating and insulates two contact regions of the leadframe, via which the semiconductor chip is electrically contacted, from one another. The carrier comprises, for example, a substantially flat mounting region, on which the semiconductor chip is fastened and electrically connected. The housing body may extend the semiconductor chip in a lateral direction, parallel to a

Main extension direction of the LED, surrounded.

For example, the housing body forms a

Semiconductor chip laterally surrounding dam. In other words, the carrier has a cavity in which the semiconductor chip is arranged.

In accordance with at least one embodiment, the semiconductor chip and the converter element are encapsulated with a radiation-permeable encapsulation, in particular completely encapsulated.

The semiconductor chip includes, for example, a

Radiation exit surface, which is a main side of the

Semiconductor chips forms and over in the intended Operating at least 50% or at least 80% of the first

Radiation can be coupled out of the semiconductor chip. Furthermore, the semiconductor chip, for example, transversely to

Radiation exit surface extending side surfaces. The radiation exit surface is, for example, facing away from the mounting region of the carrier. The radiation-permeable encapsulation covers the radiation exit surface and the side surface partially or completely. Preferably covers the

radiation-permeable encapsulation also partially or a side facing away from the carrier of the converter element

Completed .

The dam of the wearer surrounds, for example, the

radiation-permeable potting and prevents in the

Inserting the potting a lateral or lateral

Outflow of potting. In other words, the cavity of the carrier is filled with the radiation-permeable encapsulation.

The radiation-permeable encapsulation is, for example, silicone or epoxy. The

Radiation-permeable potting is in particular transparent, ie clear-sighted, for the first radiation and / or the second radiation and / or the mixed radiation. In accordance with at least one embodiment, the carrier comprises or consists of gold and / or copper. In particular, the leadframe of the carrier comprises or consists of gold and / or copper. In particular, a semiconductor chip facing

Surface of the carrier and / or the leadframe comprises or consists of gold and / or copper. For the reflection of red light, gold and copper have sufficient

Reflectivity, so no silver has to be used. Gold and copper are also more corrosion resistant than silver. The Housing body may for example comprise or consist of a plastic.

According to at least one embodiment, the first one

Conversion material only in the area lateral to the

Semiconductor chip arranged on the carrier. In particular, the first conversion material is therefore not on the

Radiation exit surface of the semiconductor chip arranged. In the area laterally next to the semiconductor chip is the first

Conversion material preferably in the form of a layer

educated. This layer can be directly adjacent to the semiconductor chip in the region of the side surfaces. For example, the layer with the first conversion material covers all locations of the mounting area of the carrier that are not covered by the

Semiconductor chip are covered.

In the present case, a lateral direction is a direction parallel to the main sides of the semiconductor chip and / or parallel to a main extension direction of the semiconductor chip and / or parallel to a main extension direction of the carrier.

By means of such an arrangement of the first conversion material, it is achieved that the first radiation emitted via the radiation exit surface does not necessarily affect the first one

Conversion material meets. Rather, only the

for example, on an outer surface of the

radiation-permeable potting back-reflected first radiation or emitted from the beginning in the direction of the carrier first radiation on the first conversion material. Since only a certain proportion of the first radiation is to be converted by the first conversion material anyway, the efficiency of the component can be increased by this geometric arrangement. Preferably, the layer with the first conversion material in the region laterally next to the semiconductor chip in direct contact with the carrier, in particular the lead frame of the carrier. With regard to the thermal properties of the light-emitting diode, this is particularly advantageous because then the heat generated in the first conversion material can be dissipated quickly. Unlike just described, the first

Conversion but also the radiation exit surface and / or the side surfaces of the semiconductor chip partially or completely cover. In this case, the first one

Conversion material preferably in the form of a simple

formed coherent layer that the

Radiation exit surface, the side surfaces and the edges between the radiation exit surface and the side surfaces form-fitting nachformt. For example, the layer is in direct contact with the first conversion material

Semiconductor chip.

According to at least one embodiment, the of

Semiconductor chip emitted first radiation predominantly, that is at least 50% or at least 60% or at least 70% or at least 80% in the spectral range between 600 nm and 700 nm inclusive, preferably in

Spectral range between 630 nm and 690 nm inclusive. That is, the proportion of the first radiation lying in this spectral range makes up at least 50% or at least 60% etc. of the total intensity of the first radiation.

In particular, the first radiation is a

Intensity maximum, preferably a global one Intensity maximum, in the range between including 650 nm and 670 nm, preferably between 655 nm and 665 nm inclusive. That is, the active layer of the semiconductor chip emitted radiation in the red spectral range. In which

Semiconductor chip is, for example, a semiconductor chip based on InGaAlP.

In accordance with at least one embodiment, the second is

Radiation predominantly in the spectral range between

including 700 nm and 800 nm, preferably in

Spectral range between 700 nm and 760 nm inclusive. The second radiation includes, for example

Intensity maximum, preferably a global one

Intensity maximum, in the range between 720 nm and 740 nm inclusive, preferably between 725 nm and 735 nm inclusive.

In accordance with at least one embodiment, the first one lies

Radiation predominantly in the spectral range between

including 400 nm and 500 nm, preferably in

Spectral range between 420 nm and 480 nm inclusive. In this case, the first radiation, for example, a

Intensity maximum, preferably a global one

Intensity maximum, in the range between 440 nm and 460 nm inclusive, preferably in the range between 445 nm and 455 nm inclusive. Those of the active layer or the

Semiconductor chip emitted first radiation is then radiation in the blue spectral range. The semiconductor chip is, for example, a GaN-based semiconductor chip.

According to at least one embodiment, this includes

Converter element a second conversion material. The second conversion material is set up, the first Radiation predominantly in radiation in the spectral range

between 600 nm and 700 nm inclusive, preferably in

Radiation in the spectral range between 630 nm and 690 nm, inclusive.

In particular, the second conversion material comprises all converter particles of the converter element, which predominantly convert into the spectral range between 600 nm and 700 nm inclusive.

The second conversion material is chosen in particular such that the radiation converted by the second conversion material has an intensity maximum in the range around 660 nm, for example in the range between 650 nm and 670 nm inclusive.

The second conversion material may contain one or more different substances, in particular several different ones

Having particles or molecules. For example, the second conversion material comprises or consists of an alkaline earth silicon nitride and / or an alkaline earth aluminum silicon nitride. The alkaline earth metal is, for example, barium or calcium or strontium. For converting light, the second conversion material may be doped with a rare earth ion, such as Eu2 ⁺ , as an activator.

The second conversion material can be like the first one

Conversion material in the form of a layer, wherein the above definitions for a layer and the specified layer thicknesses may also apply here. In addition, the second conversion material may also be in a matrix, for example of the above-mentioned materials,

be embedded. The layer with the second Conversion material can be on and / or next to the

Semiconductor chip be arranged. In particular, the layer with the second conversion material may be arranged exclusively laterally next to the semiconductor chip. The layer with the second conversion material can also by

Sedimentation be prepared.

The first conversion material and the second

Conversion material may be mixed, for example, within a common matrix of the above

Materials. The two conversion materials are then preferably homogeneously as particles or molecules and not ^¬ deterministic distributed in the matrix material. Alternatively, however, the first conversion material and the second conversion material may also be spatially separated from one another, for example in two separate layers. The two layers can be in direct contact with each other.

According to at least one embodiment, the first one

Conversion material in the area lateral to the

Semiconductor chip between the carrier and the second

Conversion material arranged. In this case, it is particularly advantageous that the radiation converted by the first conversion material and emitted in the direction away from the carrier has energies that are generally not

sufficient to stimulate the second conversion material. The radiation can thus pass the second conversion material almost lossless.

In accordance with at least one embodiment, the second one

Conversion material in the area lateral to the Semiconductor chip disposed between the carrier and the first conversion material. For example, the second conversion material, especially the one formed thereby

Layer, in direct contact with or in close proximity to the carrier or leadframe. As in the conversion of blue light to red light through the second

Conversion material is generated a lot of heat, it is

advantageous to arrange the second conversion material near the carrier.

In accordance with at least one embodiment, the spectrum of the mixed radiation has a third local intensity maximum in a third spectral range. The third spectral range is the range between 420 nm and 480 nm inclusive, preferably between 440 nm and 460 nm inclusive,

more preferably between 445 nm and 455 nm inclusive.

According to at least one embodiment, the proportion of the mixed radiation lying in the third spectral range of the total intensity of the mixed radiation is at least 10% or at least 15% of that in the first spectral range

Proportion of mixed radiation in the total intensity of

Mixed radiation. Alternatively or additionally, the proportion of the mixed radiation lying in the third spectral range in the total intensity of the mixed radiation is at most 40% or at most 30% or at most 25% of that in the first

Such a proportion of blue radiation in the spectrum has proved to be particularly advantageous for plant growth. In accordance with at least one embodiment, the light-emitting diode comprises a third conversion material, which comprises the first radiation predominantly in radiation in the spectral range between

including 500 nm and 600 nm, so in the green

Spectral range converted.

In accordance with at least one embodiment, the light-emitting diode is used as an illumination means in plant cultivation or

Plant breeding used. In particular, the light emitting diode is used to grow plants. The light-emitting diode can be used for example in a greenhouse.

In addition, a procedure for operating a

LED indicated. In accordance with at least one embodiment, a light-emitting diode described here is used for the method for operating a light-emitting diode. That is, all features disclosed in connection with the light emitting diode are also disclosed for the method for operating a light emitting diode and vice versa.

In accordance with at least one embodiment, the method for operating a light-emitting diode comprises a step A), in which a light-emitting diode is driven in a pulsed operating mode. The pulse duration, that is the

Energizing duration of the light emitting diode, chosen shorter than the lifetime of the conversion element excited states of the converter element. In particular, the pulse duration is selected to be shorter than the lifetime of the excited states of the first conversion material. For example, the lifetime of the excited states is between 50 ys and 50 ms inclusive. The pulse duration is for example at most half of this life. In accordance with at least one embodiment, the method for operating a light-emitting diode comprises a step B) in which the repetition rate of the pulses, that is to say the frequency of the pulses

Pulse, is varied until the mixed radiation emitted by the light emitting diode, the desired ratio between the lying in the second spectral portion of the mixed radiation and the lying in the first spectral portion of the

Having mixed radiation. By the energization of the semiconductor chip first radiation is generated, which is converted by the converter element. By increasing the repetition rate of the energization of the

Semiconductor chips can be achieved that the

Converter element assumes a saturation state by no further states are excited. Will the

Repeat rate further increased, the additionally generated first radiation is no longer absorbed by the converter element, in particular no longer from the first conversion material, but only transmitted. In this respect, it can be controlled which portion of the radiation is ultimately converted.

An example of the operation of the light emitting diode is as follows: The semiconductor chip used is an InGaAlP semiconductor chip which emits first radiation in a wavelength range from 585 nm to 730 nm, preferably with an intensity maximum at approximately 660 nm. The converter element comprises, for example, a first conversion material with converter molecules in which the luminescence lifetime of the light-emitting states is in the range between 100 ns and 100 ms inclusive, preferably in the range between 50 ys and 50 ms inclusive. Due to the long life of the excited

Luminescence state is always part of the operation the converter molecules in the excited state. On this basis, the transmissivity of the converter element can be adjusted. The semiconductor chip may, for example, be operated in a pulsed operating mode with an energizing pulse duration of between 1 ys and 50 ys inclusive.

During a pulse, the excited ones remain

Converter molecules predominantly in the excited state and go for the most part only after the Bestromungs pulse in the

Ground state over. Will now the repetition rate of

Increasing the current supply, so a saturation state can be achieved by almost all converter molecules are excited. In this way, the ratio between the first

Radiation and the second radiation can be adjusted in the mixed radiation and optimally to the different

Plants, vegetation periods and / or growth phases are adjusted.

In addition, a method of producing a

LED indicated. The method is particularly suitable for producing a light-emitting diode described here. That is, all in connection with the light emitting diode

disclosed features are also for the method for

Production of a light-emitting diode disclosed and vice versa. In accordance with at least one embodiment, the method for producing a light-emitting diode comprises a step A), in which a first radiation of a first radiation in operation

Wavelength-emitting semiconductor chip is applied to a carrier.

In accordance with at least one embodiment, the method comprises a step B) in which a conversion material is applied to the Carrier is applied only in the area next to the semiconductor chip.

Preferably, the conversion material is applied together with a matrix material. The conversion material then particularly preferably sediments into a layer.

In particular, a conversion element is formed in step B). The conversion material may be the above-specified first conversion material or the second conversion material or both the first and second conversion materials.

A radiation exit surface of the semiconductor chip

preferably not covered by the conversion material

In accordance with at least one embodiment, the method comprises a step C), in which a radiation-permeable potting, for example of clear silicone or epoxy, on the

Semiconductor chip and the conversion material is applied.

In accordance with at least one embodiment of the method for producing a light-emitting diode, in step B) first a first conversion material and then a second conversion material are applied to the carrier or

vice versa. In step B), the first and / or the second conversion material can only be located in the area next to

Semiconductor chip are applied. One of the two

Conversion materials can also be applied to the semiconductor chip.

In the method, the first conversion material and / or the second conversion material are preferably each formed in the form of a layer. These can be the Conversion materials, for example, in a liquid or viscous matrix material, for example in one of the above-mentioned matrix materials, be distributed and applied together with this matrix material. By sedimentation then the conversion materials can deposit on and / or next to the semiconductor chip and there each one

Forming a layer. The layers with the different ones

Conversion materials are formed in particular successively.

Hereinafter, a light-emitting diode described here and a method described here for producing a

Light emitting diode with reference to drawings based on

Embodiments explained in more detail. The same reference numerals indicate the same elements in the individual figures. However, there are no scale references shown, but individual elements may be shown exaggerated for better understanding. Show it:

FIGS. 1A to 1C show various positions in a first exemplary embodiment of the method for producing a light-emitting diode,

FIGS. 2A to 2D different positions in a second exemplary embodiment of the method for producing a light-emitting diode, FIGS. 3A to 3C different positions in a third exemplary embodiment of the method for producing a light-emitting diode, 4A to 4E different positions in a fourth embodiment of the method for producing a light-emitting diode, Figures 5A and 5B spectra of various

Embodiments of a light-emitting diode emitted

Mixed radiation.

In FIG. 1A, a first position of a first one is shown

Embodiment of a method for producing a light emitting diode shown. In the area of a cavity of a

Carrier 4 and on a substantially planar or planar mounting portion 40 of the carrier 4, a semiconductor chip 1 is arranged. The semiconductor chip 1 is, for example, an InGaAlP volume emitter. Likewise, however, an InGaAlP thin-film semiconductor chip is conceivable.

The carrier 4 comprises a lead frame 41 and a

Housing body 42. The lead frame 41 is formed, for example, of gold or copper. The leadframe 41 includes two contact areas that are mechanically connected to each other via the housing body 42 and through the housing body 42

are electrically isolated from each other. The housing body 42 is made of, for example, an electrically insulating material such as plastic. The housing body 42 forms a

Dam, the mounting portion 40 of the carrier 4 and the semiconductor chip 1 laterally, that is along a

Main extension direction of the support 4 surrounds. The semiconductor chip 1 is electrically conductive with the two

Contact areas of the lead frame 41 connected. The lateral extent of the carrier 4 is, for example, at least twice and at most ten times as large as the lateral extent of the semiconductor chip 1.

In the second position of the illustrated in Figure 1B

Method is the semiconductor chip 1 with a potting compound 26, 21 potted. The dam from the housing body 42 acts as a barrier and prevents lateral leakage of the potting compound 26, 21. The potting compound 26, 21 comprises a matrix material 26, for example epoxy or silicone, in which a first conversion material 21 in the form of

Converter particles 21 is introduced. Both

Converter particles 21 are, for example, organic or organometallic molecules, such as coumarins or rhodamines. The first conversion material 21 is in particular configured to emit a first radiation from the

Semiconductor chip 1 predominantly in a second radiation in the spectral range between 700 nm and 800 nm to convert. The figure IC shows another position in the process in which the light-emitting diode 100 is completed. By

Sedimentation have the converter particles 21 on the semiconductor chip 1 and the remaining parts of the

Mounting portion 40 of the support 4 deposited and formed a layer. This layer represents a converter element 2 for the semiconductor chip 1. The layer thickness of the converter element 2 is, for example, approximately 10 μm. Part of the

Matrix material 21 from which the converter particles 21

have migrated, formed a radiation-permeable, in particular transparent encapsulation 5, both the

Converter element 2 and the semiconductor chip 1 covers. In the present case, the converter element 2 covers both a radiation exit surface, ie the carrier 4

remote from the main side of the semiconductor chip 1, as well

Areas of the carrier 4 laterally adjacent to the semiconductor chip 1. In the area laterally adjacent to the semiconductor chip 1 is the

Converter element 2 in direct contact with the carrier 4, in particular with the lead frame 41st

If the semiconductor chip 1 emits the first radiation of a first wavelength range, then this first crosses over

Radiation inevitably the converter element 2 and is therefore partially in the second radiation of a second

Wavelength range converted. A part of the unconverted first radiation leaving the converter element 2 and into the radiation-permeable encapsulation 5

occurs, is at the the carrier 4 and the

Semiconductor chip 1 facing away from the outside of the potting 5 5 and can again meet the converter element 2, for example in the area laterally adjacent to the semiconductor chip 1, where again a part is converted. Due to the direct contact with the carrier 4, a particularly efficient cooling of the converter element 2 can take place here.

FIGS. 2A to 2D show different positions in a second exemplary embodiment of the method

Production of a light-emitting diode shown.

The position shown in FIG. 2A corresponds to the position of FIG. 1A.

In the position of FIG. 2B, as in FIG. 1B, a potting compound 26, 21 is applied to the carrier 4 in the mounting region 40. In the present case, the potting compound 26, 21st but applied only in the area laterally adjacent to the semiconductor chip 1 on the mounting portion 40 of the carrier 4, so that the radiation exit surface of the semiconductor chip 1 is not covered by the potting compound 26, 21.

In the position shown in FIG. 2C, the light-emitting diode 100 is completed, for example. However, in FIG. 2C, it may also be only an intermediate step before the

Completion of the LED act. After a certain time, the first conversion material 21 has gone through

Sedimentation in the area laterally deposited next to the semiconductor chip 1 on the support 4 and there a layer

formed, which is a converter element 2. The first radiation emitted during operation of the light-emitting diode 100 from the

Radiation exit surface of the semiconductor chip 1 exits, the LED 100 can leave unhindered. The first radiation, which leaves the semiconductor chip 1 via side surfaces in the direction of the carrier 4, on the other hand encounters the

Converter element 2 and is partially converted into the second radiation. This in turn can then be coupled out in the direction away from the carrier 4 from the light-emitting diode 100.

Together, the light-emitting diode 100 then emits mixed radiation of the first radiation and the second radiation.

Thus, the conversion efficiency or the ratio between the second radiation and the first radiation of the

LED 100 corresponds to the figure IC, the layer thickness of the converter element 2 is preferably selected to be larger,

for example, about 20 ym. FIG. 2D shows a light-emitting diode 100 which is composed of the light-emitting diode 100 of FIG. 2C after another

Process step results. The further method step consists in the semiconductor chip 1, in particular the Radiation exit surface of the semiconductor chip 1, with an additional radiation-transmissive, in particular

cover transparent potting 5. As a result, part of the first radiation exiting via the radiation exit surface of the semiconductor chip 1 is reflected on the outside of the encapsulation 5 facing away from the semiconductor chip 1 in the direction of the carrier 4 and partially converted there by the converter element 2 into the second radiation. The conversion efficiency of the light-emitting diode 100 of FIG. 2D is thus in principle greater than in the case of the light-emitting diode 100 of FIG. 2C, for which reason

For example, the layer thickness of the converter element 2 can be selected smaller.

FIG. 5A shows an exemplary embodiment of a spectrum of the mixed radiation emitted by the light emitting diodes 100 of FIGS. 1 and 2. Shown is the intensity distribution of the mixed radiation as a function of the wavelength. The spectrum has two local intensity maxima, with the first intensity maximum at about 660 nm and the second

Intensity maximum at about 730 nm. The

Intensity maxima are peaks of two significant peaks. The first peak at 660 nm is predominantly generated by the first radiation emitted directly by the semiconductor chip 1. The second peak at 730 nm essentially comes from the second converted by the converter element 2

Radiation. The proportion of mixed radiation around the first

Intensity maximum in the first spectral range 31 between 630 nm and 690 nm, for example, about 5 times greater than the proportion of mixed radiation to the second intensity maximum in the second spectral range 32 between 700 nm and 760 nm inclusive. The spectrum of the mixed radiation shown is particularly advantageous for the irradiation of plants in the rearing of plants. Due to the selected proportions of the mixed radiation in the range around 660 nm and in the range around 730 nm, a particularly efficient photosynthesis can take place.

FIGS. 3A to 3C show various positions of a third exemplary embodiment of a method for producing a light-emitting diode.

The position shown in FIG. 3A essentially corresponds to the position of FIG. 1A. Instead of an InGaAlP semiconductor chip is in the present case but a

blue emitting chip, for example, an InAlGaN semiconductor chip 1 used.

In the position of FIG. 3B, a potting compound 26, 21, 22 comprising a matrix material 26 with a first conversion material 21 and a second material introduced therein is applied to the mounting region 40 of the carrier 4 and to the semiconductor chip 1

Conversion material 22 applied. The first

Conversion material 21 and the second conversion material 22 are in the form of converter particles, for example. The first conversion material 21 can, as in the

Be selected embodiments of Figures 1 and 2. The second conversion material 22 is, for example, chosen so that it emerges from the semiconductor chip 1 first

Radiation predominantly in radiation in the spectral range

between 600 nm and 700 nm inclusive.

FIG. 3C shows a position in which the light-emitting diode 100 is completed. The converter particles of the conversion materials 21, 22 have gone through Sedimentation on the radiation exit surface of the

Semiconductor chips 1 and in the area laterally next to the

Semiconductor chips 1 deposited on the mounting portion 40 of the support 4 and there formed a simply continuous layer, which is a converter element 2. Within the layer, the converter particles are homogeneously distributed. The layer thickness of the converter element 2 is, for example, between 30 ym and 50 ym inclusive. In FIGS. 4A to 4E, various positions are shown in a fourth embodiment of a method for

Production of a light-emitting diode shown.

The position of FIG. 4A corresponds to the position of FIG. 3A.

In the position of FIG. 4B, a potting compound 26, 21 is introduced into the cavity of the carrier 4 exclusively in the area laterally next to the semiconductor chip 1. The

Radiation exit surface of the semiconductor chip 1 is not covered by the potting compound 26, 21. The potting compound 26, 21 comprises a matrix material 26 and a first

Conversion material 21, which are selected, for example, as in the above embodiments.

FIG. 4C shows a position of the method in which the first conversion material 21 has been deposited by sedimentation in the form of a layer of approximately 10 .mu.m thickness in the area laterally next to the semiconductor chip 1. The

Radiation exit surface of the semiconductor chip 1 is free of the first conversion material 21st

FIG. 4D shows a position of the method, in which a further potting compound 26, 22 in the region of the cavity of the carrier 4 is applied to the semiconductor chip 1. The further potting compound 26, 22 again comprises a matrix material 26 and a second conversion material 22, which is selected, for example, as in the previous exemplary embodiment.

FIG. 4E shows a position of the method in which the light-emitting diode 100 is completed. The second

Conversion material 22 has in turn deposited by sedimentation on the radiation exit surface of the semiconductor chip 1 and in the region laterally adjacent to the semiconductor chip 1 in the form of a coherent layer. This is one

Converter element 2 is formed, which has a two-layer structure in the area laterally adjacent to the semiconductor chip 1 and a single-layer structure on the semiconductor chip 1.

Laterally next to the semiconductor chip 1, a layer with the first conversion material 21 is arranged between a layer with the second conversion material 22 and the carrier 4. On the semiconductor chip 1, only one layer with the second conversion material 22 is arranged.

FIG. 5B shows an exemplary embodiment of a spectrum of the mixed radiation emitted by the light emitting diodes 100 of FIGS. 3 and 4. The spectrum has three local intensity maxima in the form of peaks. A first

The maximum intensity is approximately 450 nm and results from the first radiation emitted by the semiconductor chip 1. The second intensity maximum is approximately 660 nm. This peak results in particular from the conversion of the first radiation emitted by the semiconductor chip 1 through the second conversion material 22. The third intensity maximum is approximately 730 nm. This peak results in particular from the conversion of radiation through the first

Conversion material 21. The proportion of the mixed radiation in the first spectral range 31 is approximately 5 times greater than the proportion of the mixed radiation in the second spectral range 32 and in the third

Spectral range 33 between 420 nm and 480 nm inclusive.

Such a spectrum of mixed radiation is special

advantageous for plant breeding, since in this spectrum also important for photosynthesis blue content is included.

The light-emitting diodes 100 illustrated in FIGS. 1 to 4 each have a carrier with a cavity in which the semiconductor chip 1 is arranged. This cavity is filled with a casting. Alternatively, it would also be possible to mount the semiconductor chip 1 on a flat carrier without cavity, for example on a ceramic carrier. The semiconductor chip 1 can then, for example, with a molding injection molding process (Molden) with a

Potting compound to be overmolded, wherein a converter element 2 then as in the embodiments shown by

Sedimentation can occur.

In the embodiments of Figures 1 to 4, moreover, the converter element 2 is always within the cavity of the

Carrier 4 arranged. Alternatively, it would also be conceivable for the cavity initially to be provided with a radiation-permeable, in particular transparent, potting 5, such as silicone,

fill up and then apply the converter element 2 on this radiation-permeable encapsulation 4. The

Converter element 2 could then be designed, for example, lens-shaped. This patent application claims the priority of German Patent Application 10 2017 120 642.6, the disclosure of which is hereby incorporated by reference. The invention is not limited by the description based on the embodiments of these. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes any combination of features in the patent claims, even if these features or this combination itself are not explicitly incorporated in the claims

Claims or embodiments is given.

Reference sign list

1 semiconductor chip

2 converter element

4 carriers

5 radiation-permeable potting

21 first conversion material

22 second conversion material

26 matrix material

31 first spectral range

32 second spectral range

33 third spectral range

40 mounting area

41 ladder frame

42 housing body

100 light emitting diode

Claims

claims

1. Light-emitting diode (100), comprising:

- An optoelectronic semiconductor chip (1) and a

Converter element (2),

wherein the semiconductor chip (1) and the converter element (2) are arranged so that in normal operation

the semiconductor chip (1) emits first radiation,

- The converter element (2) a part of the

Semiconductor chip (10) emitted first radiation converted into second radiation,

the light-emitting diode (100) emits mixed radiation from the unconverted first radiation and the second radiation,

the mixed radiation has a spectrum with a first and a second local intensity maximum,

- the first intensity maximum in a first

Spectral range (31) is between 630 nm and 690 nm inclusive and the second intensity maximum in a second spectral range (32) between 700 nm and 760 nm inclusive,

- The portion of the mixed radiation in the second spectral range (32) in the total intensity of the mixed radiation at least 10% and at most 40% of the first

Spectral range (31) lying proportion of the mixed radiation in the total intensity of the mixed radiation.

2. Light-emitting diode (100) according to claim 1, wherein

the first radiation (11) lies predominantly in the spectral range between 400 nm and 500 nm inclusive,

the converter element (2) comprises a second conversion material (22), the second conversion material (22) converts the first radiation predominantly into radiation in the spectral range between 600 nm and 700 nm inclusive,

the light-emitting diode (100) comprises a carrier (4) and the semiconductor chip (1) and the converter element (2) are applied to the carrier (4),

the carrier (4) comprises a metallic lead frame (41) and faces the semiconductor chip (1)

Surface of the lead frame (41) comprises gold,

the second conversion material (22) is arranged in the form of a layer next to the semiconductor chip (1),

the thickness of the layer with the second conversion material

(22) is between 5 ym and 30 ym inclusive.

3. light-emitting diode (100) according to claim 1 or 2, wherein

the first local intensity maximum in one

Spectral range between 650 nm and 670 nm inclusive and the second local intensity maximum in one

Spectral range between 720 nm and 740 nm inclusive,

the portion of the mixed radiation lying in the second spectral range (32) is at least 15% and at most 25% of the portion of the spectrum lying in the first spectral range (31)

Mixed radiation is.

4. Light-emitting diode (100) according to one of the preceding claims, wherein

the converter element (2) comprises or consists of a first conversion material (21)

the first conversion material (21) converts the first radiation (11) predominantly into radiation in the spectral range between 700 nm and 800 nm inclusive.

5. Light-emitting diode according to claim 4, wherein

the first conversion material (21) in the form of a layer on and / or laterally next to the semiconductor chip (1)

is arranged

the thickness of the layer with the first conversion material (21) is between 5 ym and 30 ym inclusive.

6. light-emitting diode (100) according to any one of claims 1 and 3 to 5, further comprising a support (4), wherein

the semiconductor chip (1) and the converter element (2) are applied to the carrier (4),

the semiconductor chip (1) and the converter element (2) are encapsulated with a radiation-permeable encapsulation (5). 7. light-emitting diode (100) according to claim 6,

wherein the carrier (4) comprises or consists of gold and / or copper.

8. Light-emitting diode according to at least claims 4 and 6,

wherein the first conversion material (21) is arranged only in the region laterally next to the semiconductor chip (1) on the carrier (4).

9. light-emitting diode (100) according to any one of the preceding claims 1 and 3 to 8, wherein

the first radiation (11) lies predominantly in the spectral range between 600 nm and 700 nm inclusive,

the second radiation (12) lies predominantly in the spectral range between 700 nm and 800 nm inclusive.

10. Light-emitting diode (100) according to any one of claims 1 and 3 to 8, wherein the first radiation (11) lies predominantly in the spectral range between 400 nm and 500 nm inclusive,

the converter element (2) comprises a second conversion material (22),

the second conversion material (22) converts the first radiation predominantly into radiation in the spectral range between 600 nm and 700 nm inclusive.

11. Light-emitting diode (100) according to at least claims 5 and 10, wherein

the first conversion material (21) is arranged in the region laterally next to the semiconductor chip (1) between the carrier (4) and the second conversion material (22).

12. Light-emitting diode (100) according to at least claims 5 and 10, wherein

the second conversion material (22) is arranged in the region laterally next to the semiconductor chip (1) between the carrier (4) and the first conversion material (21).

13. Light-emitting diode (100) according to at least claim 10, wherein

the spectrum of mixed radiation a third local

Intensity maximum in a third spectral range (33) between 420 nm and 480 nm inclusive, the lying in the third spectral range (33) proportion of the mixed radiation in the total intensity of the mixed radiation at least 10% and at most 40% of the first

14. Light-emitting diode (100) according to one of claims 10 to 13, further comprising: a third conversion material that converts the first radiation predominantly into radiation in the spectral range between 500 nm and 600 nm inclusive.

15. Use of a light-emitting diode (100) according to one of

previous claims as lighting means in

Plant cultivation.

16. A method of operating a light emitting diode (100),

comprising the steps:

A) driving a light-emitting diode (100) according to one of claims 1 to 14 in a pulsed mode of operation, wherein the

Pulse duration is selected shorter than the life of the excited during the conversion states of the converter element (2);

B) variation of the repetition rate of the pulses until the

Mixed radiation, the desired ratio between the lying in the second spectral range (32) share the

Having mixed radiation and in the first spectral range (31) lying proportion of the mixed radiation.

17. A method for producing a light-emitting diode (100), comprising the steps:

A) arranging a first radiation of a first during operation

Wavelength range emitting semiconductor chips (1) on a support (4);

B) applying a conversion material (21, 22) on the

Carrier (4) only in the area next to the semiconductor chip (1);

C) applying a radiation-permeable encapsulation (5) on the semiconductor chip (1) and the conversion material (21, 22).

18. The method according to claim 17, wherein in step B) first a first conversion material (21) and then a second

Conversion material (22) are applied to the support (4) or vice versa.