Conversion element, method for manufacturing a conversion element, optoelectronic component comprising a conversion element

Abstract

Conversion element (1) - comprising an inorganic glass with a plate (2), - with first converter particles (3), wherein - the first converter particles (3) have a shell (3a) and a core (3b), - wherein the shell (3a) comprises an inorganic material and has a thickness between at least 10 nm and at most 50 µm, and - the core (3b) comprises a nitridic or oxynitridic phosphor and - wherein the first converter particles (3) are arranged on and / or in the plate (2).

Description

[0001] The invention relates to a conversion element, a method for producing a conversion element and an optoelectronic component comprising a conversion element.

[0002] Optoelectronic components such as light-emitting diodes (LEDs) often contain conversion elements with a phosphor. Phosphors convert the radiation emitted by a radiation source into radiation with a modified wavelength, for example, a longer wavelength. This process generates heat in addition to the emitted modified radiation. Conventional conversion elements often use silicone as a matrix for the phosphors. However, silicone exhibits insufficient heat dissipation of the heat generated by the phosphor. This results in a heat buildup in the conversion elements, which leads to a reduction in luminosity and a change in the color coordinate, as well as premature failure of the LED. The documents DE 10 2011 078 663 A1, US 2013 / 0207 073 A1, DE 10 2005 045 106 A1 and US 2013 / 0 002 124 A1 describe conversion elements, LEDs with conversion elements and materials for conversion elements.

[0003] The object of at least one embodiment of the present invention is to provide a conversion element with improved properties compared to the prior art, which can also be manufactured cost-effectively. A further object is to provide an optoelectronic component comprising a conversion element that is improved compared to the prior art.

[0004] The object is achieved by a conversion element having the features of claim 1, by a method for producing a conversion element having the features of claim 9 and by an optoelectronic component having the features of claim 14.

[0005] A conversion element is specified. The conversion element comprises a platelet comprising an inorganic glass and first converter particles. The first converter particles have a shell and a core, wherein the shell comprises an inorganic material and the core comprises a nitride or oxynitride phosphor. The first converter particles are arranged on and / or in the platelet comprising the inorganic glass.

[0006] The fact that the first converter particles are arranged in the platelet comprising the inorganic glass means that the first converter particles are fully or partially embedded in the platelet, i.e., in the inorganic glass of the platelet. For example, in the case of partial embedding, 20% to 99.9% of the surface of the shell of the first converter particles can be surrounded by the inorganic glass of the platelet or be in direct mechanical contact with it.

[0007] In one embodiment, a portion of the first converter particles is arranged on the plate and a portion of the first converter particles is arranged in the plate.

[0008] According to one embodiment, the core consists of a nitride or oxynitride phosphor, in particular of nitride or oxynitride phosphor particles. Preferably, the core consists of a nitride phosphor or nitride phosphor particles.

[0009] A conversion element comprising an inorganic glass allows the heat generated by the first converter particles to be dissipated very effectively within the conversion element. This results in low or negligible heat buildup within the conversion element. If the conversion element is part of an optoelectronic component, a constant luminosity and a constant color coordinate can be guaranteed over the entire operating life of the optoelectronic component. This prevents premature failure of the optoelectronic component and extends its service life.

[0010] The fact that a layer or element is arranged or applied "on" or "over" another layer or element can mean here and below that one layer or element is arranged in direct mechanical and / or electrical contact with the other layer or element. Furthermore, it can also mean that one layer or element is arranged indirectly on or over the other layer or element. In this case, further layers and / or elements can be arranged between one or the other layer or between one or the other element.

[0011] The platelet can consist of the inorganic glass or of the inorganic glass and the first converter particles.

[0012] In one embodiment, the inorganic glass has a refractive index η D(20 °C) between 1.0 and 3.0, preferably between 1.4 and 3.0, particularly preferably between 1.9 and 3.0.

[0013] In one embodiment, the inorganic glass has a thermal conductivity between 0.5 W m -1 K -1 and 3.0 W m -1 K -1 , preferably between 0.6 W m -1 K -1 and 1.5 W m -1 K -1 , particularly preferably between 0.6 W m -1 K -1 and 0.9 W m -1 K -1 on.

[0014] In one embodiment, the inorganic glass is a silicate glass, a borate glass, or a phosphate glass. The silicate glass contains SiO2 as its main component, the borate glass contains B2O3 as its main component, and the phosphate glass contains P2O5 as its main component. The silicate glass may contain other metal oxides such as B2O3, P2O5, Na2O, K2O, Bi2O3, and AgO; the borate glass may contain other metal oxides such as SiO2, P2O5, Na2O, K2O, Bi2O3, and AgO; and the phosphate glass may contain other metal oxides such as B2O3, SiO2, Na2O, K2O, Bi2O3, and AgO. For example, the inorganic glass is a soda-lime glass.

[0015] In one embodiment, the platelet comprising or consisting of the inorganic glass is transparent. "Transparency" is understood here to mean that a material, layer, or element is at least partially permeable to the entire visible electromagnetic spectrum or a sub-spectrum thereof.

[0016] Nitridic and oxynitridic phosphors are characterized by the fact that these phosphors contain at least one N 3- -ion ​​in their composition. Nitride phosphors do not have any oxygen atoms in their composition. Oxynitride phosphors have, in addition to N 3- at least one O 2--ion ​​in their composition. For example, the nitride phosphor is a phosphor of the formula M2Si5N8 or MAlSiN3 and the oxynitride phosphor is a phosphor of the formula MSi2N2O2. In the formulas mentioned, M stands for an alkaline earth metal or combinations of several alkaline earth metals. For example, M is selected from a group comprising Ba, Sr, Ca, Mg and combinations thereof. In one embodiment, the oxynitride and nitride phosphors are doped, for example, with one of the following activators or combinations of the following activators: cerium, europium, terbium, praseodymium, saramium, manganese. The phosphors are preferably doped with Eu 2+ For example, it is a red-emitting nitride phosphor (Ca,Sr,Ba)2Si5N8:Eu 2+ or (Sr,Ba)2Si5N8:Eu 2+ .

[0017] In one embodiment, the nitride phosphor is a phosphor that emits red light and the oxynitride phosphor is a phosphor that emits green to orange light.

[0018] Nitridic or oxynitridic phosphors react with the inorganic glass, resulting in a lower efficiency of the phosphors. It has been shown that first converter particles comprising or consisting of a shell made of an inorganic material and a core made of a nitridic or oxynitridic phosphor can be incorporated into inorganic glass while maintaining their efficiency. The shell comprising or consisting of the inorganic material protects the nitridic or oxynitridic phosphor located in the core of the first converter particles from reacting with the inorganic glass. This allows the efficiency of the nitridic or oxynitridic phosphors to be maintained, and the resulting heat can be efficiently dissipated through the inorganic glass.

[0019] In one embodiment, the inorganic material of the shell is selected from a group comprising SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene, and combinations thereof. Preferably, the inorganic material of the shell is selected from a group comprising SiO2, TiO, B2O3, ZrO, an inorganic-organic hybrid material, AlN, TiN, Si3N4, and combinations thereof.

[0020] The shell can be made of inorganic material.

[0021] In one embodiment, the inorganic-organic hybrid material comprises Si-O-Si bonds.

[0022] In one embodiment, the inorganic-organic hybrid material is produced by hydrolysis and condensation of tetraethoxysilane and / or tetramethoxysilane, preferably tetraethoxysilane. In particular, the process for producing the inorganic-organic hybrid material is a sol-gel process.

[0023] The first converter particles can have cores with different nitride and / or oxynitride phosphors and also different shells. For example, the first converter particles can be composed of first converter particles with a core made of a nitride phosphor and first converter particles with a core made of an oxynitride phosphor. The first converter particles can have the same or different shells.

[0024] In one embodiment, the platelet has two main surfaces. The first main surface is the one to which the first converter particles are spatially closest and usually corresponds to the surface to which the converter particles were applied during the production of the converter element. The main surface opposite the first main surface is referred to as the second main surface.

[0025] According to one embodiment, the conversion element has a thickness between 100 µm and 200 µm. Preferably, the conversion element has a thickness between 150 µm and 200 µm.

[0026] In one embodiment, the first converter particles have a diameter between 10 µm and 100 µm, preferably between 10 µm and 50 µm, particularly preferably between 10 µm and 30 µm.

[0027] The shell can have a thickness between 10 nm and 50 µm, preferably between 100 nm and 5 µm, particularly preferably between 100 nm and 5 µm. The thickness can be selected differently depending on the manufacturing process. If the shell has a high degree of impermeability, a thin thickness can be selected. In one embodiment, a protective layer is arranged over the platelet, which protective layer comprises a material selected from a group comprising parylene, polysilazane, silicone, SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene, an inorganic glass, and combinations thereof. The inorganic-organic hybrid material can be selected in the same way as the inorganic-organic hybrid material of the shell. The inorganic glass may be selected from the same group as that specified for the inorganic glass of the platelet.Preferably, the material is selected from a group consisting of parylene, polysilazane, silicone, SiO2, AlN, TiN, Si3N4, ZrN, graphene, an inorganic glass, and combinations thereof. Preferably, the protective layer is disposed over the first main surface of the platelet.

[0028] The same or different materials can be chosen for the shell of the first converter particles and for the first protective layer. The platelet and the protective layer can comprise or consist of the same inorganic glass.

[0029] In particular, a protective layer is arranged over the platelet, preferably over the first main surface of the platelet, when the first converter particles are arranged on the platelet and / or partially embedded in the platelet. The protective layer can completely cover the first converter particles.

[0030] In one embodiment, the first converter particles are completely embedded in the inorganic glass of the plate and the material of the protective layer. In this embodiment, the first converter particles are completely surrounded by the protective layer and the inorganic glass of the plate and thus have no contact with the ambient air. In particular, there is direct mechanical contact between the shell of the first converter particles and the material of the protective layer and the inorganic glass of the plate.

[0031] In one embodiment, the first converter particles are completely embedded in the inorganic glass of the plate. In this embodiment, the first converter particles are completely surrounded by the inorganic glass of the plate and thus have no contact with the ambient air. In particular, there is direct mechanical contact between the shell of the first converter particles and the inorganic glass of the plate.

[0032] In one embodiment, a chemical bond and / or physical interactions exist between the inorganic material of the shell of the first converter particles and the inorganic glass of the platelet. The chemical bond can be an ionic and / or a covalent bond.

[0033] Chemical bonds and / or physical interactions may exist between the material of the protective layer and the material of the shell of the first converter particles. For example, the chemical bonds are covalent and / or ionic bonds.

[0034] Due to the chemical bonding of the first converter particles to the inorganic glass and / or the material of the protective layer, the first converter particles are firmly embedded in the conversion element and are therefore not subject to diffusion.

[0035] In one embodiment, the conversion element comprises second converter particles. The second converter particles are arranged on and / or in the platelet comprising the inorganic glass. The second converter particles can comprise an oxidic phosphor or consist of an oxidic phosphor. Oxidic phosphors are understood to be phosphors that contain at least one O 2- -ion ​​and no N3- ions in their composition. Garnets can be used as oxide phosphors, for example, yttrium aluminum garnet (YAG) or lutetium aluminum garnet (LuAG). These oxide phosphors can be incorporated or applied without a coating into the inorganic glass of the wafer while retaining their efficiency.

[0036] In one embodiment, the second converter particles are completely embedded in the inorganic glass of the plate. In this embodiment, the second converter particles are completely surrounded by the inorganic glass of the plate and thus have no contact with the ambient air. In particular, there is direct mechanical contact between the second converter particles and the inorganic glass of the plate.

[0037] The platelet may consist of the inorganic glass and the first and second converter particles.

[0038] The platelet can consist of the inorganic glass and the second converter particles. The first converter particles are then arranged on the platelet.

[0039] In one embodiment, the conversion element comprises first converter particles that emit red light and second converter particles that emit yellow and / or green light.

[0040] In one embodiment, an antireflective and / or reflective layer is arranged on the plate. The antireflective and / or reflective layer is preferably arranged above the second main surface of the plate. The antireflective and / or reflective layer can have a bandpass or edge filter characteristic. For example, an antireflective and / or reflective layer can be transparent to radiation of certain wavelengths and reflective to radiation of other wavelengths. A 3D structure that improves light extraction or includes a directional characteristic for light is also possible.

[0041] The specified embodiments of the conversion element can be manufactured according to the method described below.

[0042] Furthermore, a method for producing a conversion element is specified. The method comprises the following process steps: A) Coating particles of a nitride or oxynitride phosphor with an inorganic material selected from a group consisting of SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene, and combinations thereof. This produces first converter particles having a shell of an inorganic material and a core of the nitride or oxynitride phosphor; B) providing a platelet comprising an inorganic glass; C) melting a surface layer of the plate; E) Applying the first converter particles to the molten surface layer.

[0043] In one embodiment, the inorganic-organic hybrid material comprises Si-O-Si bonds.

[0044] In one embodiment, the inorganic-organic hybrid material is produced by hydrolysis and condensation of tetraethoxysilane and / or tetramethoxysilane, preferably tetraethoxysilane. In particular, the process for producing the inorganic-organic hybrid material is a sol-gel process.

[0045] In one embodiment, the plate has two main surfaces. The first main surface in the produced conversion element is the main surface to which the first converter particles are spatially closest. The main surface opposite the first main surface is referred to as the second main surface. In process step E), the first converter particles are applied to the first main surface of the plate. The surface layer of the plate in process step C) is the surface layer of the first main surface of the plate.

[0046] This process makes it possible to apply nitride and / or oxynitride phosphors to or into a platelet made of inorganic glass. In particular, the efficiency of the nitride and / or oxynitride phosphors in the conversion element can be maintained using this process. Previously, this was not possible because nitride and / or oxynitride phosphors or phosphor particles react with the molten inorganic glass. The molten glass contains mobile O 2- Ions that react with the nitride and / or oxynitride phosphor. This undesirable reaction leads to a loss of efficiency in the phosphors. By coating particles of a nitride or oxynitride phosphor with an inorganic material, this reaction can be avoided, thus maintaining the efficiency of the phosphors.

[0047] In one embodiment, the platelet in process step B) consists of the inorganic glass.

[0048] In one embodiment, second converter particles comprising or consisting of an oxide phosphor are arranged in the platelet comprising an inorganic glass in process step B). The platelet can consist of the inorganic glass and the second converter particles.

[0049] In one embodiment, when the first converter particles are applied to the molten surface layer in process step E), the shell of the first converter particles is melted when it comes into contact with the molten surface layer. In particular, the shell is not completely melted. This means that the inorganic material of the shell, which directly borders the core of the first converter particles, is not melted. In this way, the core, i.e. the nitride or oxynitride phosphor, can be efficiently protected from a reaction with the inorganic glass. Because the inorganic material of the shell, which directly borders the core of the first converter particles, is not melted, inorganic materials such as SiO2 can be used. If the shell were completely melted, a shell made of SiO2, for example, would also pose the risk that O 2--ions react with the nitridic or oxynitridic phosphor.

[0050] The shell can have a thickness between 10 nm and 50 µm, preferably between 100 nm and 5 µm. Choosing these thicknesses ensures that the inorganic material of the shell, which directly borders the core of the first converter particles, is not melted.

[0051] In one embodiment, process step E) is followed by a further process step: F) Partial and / or complete sinking of the first converter particles into the molten surface layer.

[0052] Complete sinking means that the first converter particles sink into the molten surface layer to such an extent that the entire surface of the shell of the first converter particles is embedded in the molten glass or is in direct mechanical contact with the molten glass. Preferably, the first converter particles only sink to such an extent that the first main surface of the platelet is spatially closer to the first converter particles than the second main surface of the platelet. Partial sinking means that the first converter particles sink into the molten surface layer to such an extent that 20% to 99.9% of the surface of the shell of the first converter particles is embedded in the inorganic glass of the platelet or is in direct mechanical contact with it.

[0053] In one embodiment of the process, physical interactions and / or chemical bonds, in particular ionic and / or covalent bonds, arise between the molten inorganic material of the shell of the first converter particles and the molten inorganic glass. The physical interactions and / or chemical bonds arise after the first converter particles are applied to the molten surface layer in process step E) or after or during the partial and / or complete sinking of the first converter particles into the molten surface layer in process step F).

[0054] In one embodiment of the process, a further process step takes place after process step C): D) Applying second converter particles comprising an oxide phosphor to the molten surface layer. In particular, the second converter particles consist of the oxide phosphor.

[0055] In contrast to nitride and oxynitride phosphors, oxide phosphors show an interaction with O 2- -ions of the molten inorganic glass, however, this interaction has no, or only a very minor, effect on the efficiency of the oxide phosphor. Since the second converter particles are thus insensitive to the molten inorganic glass, they are preferably applied to the molten surface layer before the first converter particles, or are applied and sunk into it. Furthermore, the second converter particles do not require a protective coating.

[0056] In one embodiment of the process, a further process step takes place after process step D): D1) allowing the second converter particles to sink completely into the molten surface layer.

[0057] If the surface layer is no longer melted after process step D1), process step C) can be carried out again before process step E).

[0058] In one embodiment, in process step E), the first and second converter particles are applied simultaneously to the molten surface layer. Process step D1) can then take place after process step E).

[0059] In one embodiment, a slip or a gel comprising the inorganic material, or the inorganic material in a gaseous state, is used to coat the particles of the nitridic or oxynitridic phosphor in process step A). ​​A slip is a dispersion of the inorganic material in water or in an alcohol, for example ethanol. The slip can also contain a binder, for example polyvinyl alcohol. If a gel comprising the inorganic material is used, it is, for example, a gel produced by a sol-gel process. For example, tetraethoxysilane or tetramethoxysilane can be used as the reactant in a sol-gel process. Through hydrolysis and condensation, an inorganic-organic hybrid material containing Si-O-Si bonds is formed in the sol-gel process.

[0060] After process step E) or F), a further process step can take place: G) Applying a protective layer comprising a material selected from a group consisting of parylene, polysilazane, silicone, SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene, an inorganic glass, and combinations thereof to the first main surface of the platelet. In particular, the protective layer is applied when the first converter particles are arranged on the platelet or have only partially sunk into the molten surface layer in process step F). If the protective layer comprises a material selected from a group comprising SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene and combinations thereof, it can be applied using a CVD (chemical vapor deposition) process.

[0061] After process step E), F) or G), a further process step can take place: H) Applying an anti-reflective and / or reflective layer to the second main surface of the platelet.

[0062] The specified embodiments of the conversion element can be present in an optoelectronic component.

[0063] Furthermore, an optoelectronic component is specified. The optoelectronic component comprises a layer sequence with an active layer that emits electromagnetic primary radiation during operation of the component. The optoelectronic component further comprises at least one conversion element. The conversion element comprises a plate comprising an inorganic glass and first converter particles. The first converter particles have a shell and a core, wherein the shell comprises an inorganic material and the core comprises a nitride or oxynitride phosphor. The first converter particles are arranged on and / or in the plate comprising the inorganic glass. The conversion element is arranged in the beam path of the electromagnetic primary radiation and above the layer sequence. The first converter particles at least partially convert the electromagnetic primary radiation into electromagnetic secondary radiation.

[0064] Such an optoelectronic component with a conversion element as described above exhibits a constant luminous intensity and a constant color coordinate throughout the operating life of the optoelectronic component, since the inorganic glass can very effectively dissipate the heat generated by the first converter particles in the conversion element. This prevents premature failure of the optoelectronic component and extends its service life.

[0065] The fact that converter particles at least partially convert the electromagnetic primary radiation into electromagnetic secondary radiation can mean, on the one hand, that the electromagnetic primary radiation is partially absorbed by the converter particles and emitted as secondary radiation with a wavelength range that is at least partially different from the primary radiation. Part of the absorbed primary radiation is released as heat by the converter particles. The unabsorbed electromagnetic primary radiation can be emitted.

[0066] The fact that the converter particles at least partially convert the primary electromagnetic radiation into secondary electromagnetic radiation can also mean that the primary electromagnetic radiation is almost completely absorbed by the converter particles and emitted in the form of secondary electromagnetic radiation and heat. The emitted radiation of the optoelectronic component according to this embodiment thus corresponds almost completely to the secondary electromagnetic radiation. Almost complete conversion is understood to mean a conversion of more than 95%, in particular more than 98%.

[0067] In this context, “layer sequence” is understood to mean a layer sequence comprising more than one layer, for example a sequence of a p-doped and an n-doped semiconductor layer, wherein the layers are arranged one above the other.

[0068] The layer sequence can be implemented as an epitaxial layer sequence or as a radiation-emitting semiconductor chip with an epitaxial layer sequence, i.e., as an epitaxially grown semiconductor layer sequence. The layer sequence can be implemented, for example, on the basis of InGaAlN. InGaAlN-based semiconductor chips and semiconductor layer sequences are, in particular, those in which the epitaxially produced semiconductor layer sequence comprises a layer sequence of different individual layers, which contains at least one individual layer comprising a material from the III-V compound semiconductor material system In x Al y Ga 1-x-y N with 0 ≤ x ≤ 1, 0 ≤ y ≤ 1 and x + y ≤ 1.

[0069] Semiconductor layer sequences that have at least one active layer based on InGaAlN can, for example, emit electromagnetic radiation in an ultraviolet to green wavelength range.

[0070] Alternatively or additionally, the semiconductor layer sequence or the semiconductor chip can also be based on InGaAlP, i.e. the semiconductor layer sequence can have different individual layers, of which at least one individual layer is a material from the III-V compound semiconductor material system In x Al y Ga 1-x-yP with 0 ≤ x ≤ 1, 0 ≤ y ≤ 1 and x + y ≤ 1. Semiconductor layer sequences or semiconductor chips that have at least one active layer based on InGaAlP can, for example, preferably emit electromagnetic radiation with one or more spectral components in a green to red wavelength range. Alternatively or additionally, the semiconductor layer sequence or the semiconductor chip can also have other III-V compound semiconductor material systems, for example an AlGaAs-based material, or II-VI compound semiconductor material systems. In particular, an active layer that has an AlGaAs-based material can be suitable for emitting electromagnetic radiation with one or more spectral components in a red to infrared wavelength range.

[0071] In addition to the active layer, the active semiconductor layer sequence can comprise further functional layers and functional regions, such as p- or n-doped charge carrier transport layers, i.e., electron or hole transport layers, undoped or p- or n-doped confinement, cladding, or waveguide layers, barrier layers, planarization layers, buffer layers, protective layers, and / or electrodes, as well as combinations thereof. Furthermore, one or more mirror layers can be applied, for example, to a side of the semiconductor layer sequence facing away from the growth substrate. The structures described here relating to the active layer or the further functional layers and regions are known to the person skilled in the art, particularly with regard to their design, function, and structure, and are therefore not explained in more detail here.

[0072] In one embodiment, the conversion element comprises second converter particles. The second converter particles are arranged on and / or in the platelet comprising the inorganic glass. Preferably, the second converter particles are completely embedded in the inorganic glass of the platelet. The second converter particles can comprise an oxide phosphor or consist of an oxide phosphor.

[0073] If first and second converter particles are present in the conversion element, the first converter particles can be arranged spatially closer to the first main surface than the second converter particles.

[0074] If first and second converter particles are present in the conversion element, the electromagnetic secondary radiation is composed of the electromagnetic secondary radiation of the first and second converter particles.

[0075] Preferably, the primary radiation and the secondary radiation can superimpose a white-colored luminous impression. For this purpose, the primary radiation can preferably create a blue-colored luminous impression, the secondary radiation of the first converter particles a red-colored luminous impression, and the secondary radiation of the second converter particles a yellow-colored luminous impression.

[0076] In one embodiment, the optoelectronic component emits white light with a color temperature of 2200 K to 5700 K.

[0077] In one embodiment, an adhesive layer is arranged between the layer sequence and the conversion element. The adhesive layer can, for example, comprise or consist of silicones or epoxy resins. Epoxy resins are used in particular when light is emitted in the non-blue range.

[0078] The fact that a layer or element is arranged "between" two other layers or elements can mean here and below that one layer or element is arranged in direct mechanical and / or electrical contact or in indirect contact with one of the two other layers or elements and in direct mechanical and / or electrical contact or electrical or indirect contact with another of the two other layers or elements. In the case of indirect contact, further layers and / or elements can then be arranged between one and at least one of the two other layers or elements, or between one and at least one of the two other elements.

[0079] If the first or the first and second converter particles are completely embedded in the plate, the conversion element can be arranged above the layer sequence in such a way that the first or the second main surface of the plate faces the layer sequence.

[0080] If the first converter particles are partially embedded in the plate and / or arranged on the plate, the conversion element can be arranged above the layer sequence in such a way that the second main surface of the plate faces the layer sequence.

[0081] The optoelectronic component may comprise a housing. A recess may be present in the center of the housing. The layer sequence may be mounted in the recess. The recess may be filled with a potting compound.

[0082] In one embodiment, the conversion element is arranged above the encapsulation. The encapsulation can be selected from conventional encapsulation materials.

[0083] The optoelectronic component can be a light-emitting diode, a photodiode-transistor array / module, or an optical coupler. Alternatively, an organic light-emitting diode can be selected as the optoelectronic component.

[0084] Further advantageous embodiments and developments of the invention will become apparent from the exemplary embodiments described below in conjunction with the figures.

[0085] Fig. 1a to 2b show schematic side views of different embodiments of conversion elements.

[0086] Fig. 3 and Fig. 4 show schematic side views of various embodiments of optoelectronic components.

[0087] In the exemplary embodiments and figures, identical or similarly functioning components are provided with the same reference numerals. The illustrated elements and their relative sizes are not to be considered to scale; rather, individual elements, particularly layer thicknesses, may be exaggerated for clarity.

[0088] The conversion element 1 according to Fig. Figure 1a shows a platelet 2 made of an inorganic glass, for example, borate glass. The platelet is, for example, 200 µm thick. Arranged within the platelet are first converter particles 3, which have a diameter of 30 µm. Diameter deviations of up to 10% are possible. The first converter particles 3 are completely embedded in the inorganic glass of the platelet 2 and are in direct mechanical contact with it. The first converter particles 3 consist of a core 3b and a shell 3a. The core 3b consists of a nitride phosphor with the formula M2SiN8:Eu 2+ with M = Ca, Sr, Ba or mixtures thereof and emits light in the red wavelength range of the electromagnetic spectrum. The shell 3a, for example, consists of SiO2. As in Fig. 1a, the platelet 2 has a first main surface 2a and a second main surface 2b. The first main surface 2a is at a smaller distance from the first converter particles 3 than the second main surface 2b. This results from the production of the conversion element 1, in which, in one embodiment, only a surface layer of the first main surface 2a of the platelet 2 is melted, the first converter particles 3 are applied and sink in. By applying the first converter particles 3 to the melted surface layer of the first main surface 2a of the platelet 2, the shell 3a of the first converter particles 3 is melted. This creates covalent and / or ionic bonds between the inorganic glass and the material of the shell 3a, whereby the first converter particles 3 are firmly embedded and bound in the platelet 2.A reflective and / or anti-reflective layer may be arranged over the second main surface (not shown here).

[0089] The conversion element 1 according to Fig. 1b shows in comparison to the conversion element 1 of the Fig. 1a additionally comprises second converter particles 7, which are arranged in the plate 2 and are completely embedded in the inorganic glass of the plate 2. The second converter particles 7 consist of an oxide phosphor, for example, LuAG. The conversion element 1 according to this exemplary embodiment is produced by first applying the second converter particles 7 to a melted surface layer of the first main surface 2a of the plate 2, allowing them to sink in, and then applying the first converter particles 3 to the melted surface layer of the first main surface 2a of the plate 2, allowing them to sink in.

[0090] The conversion element 1 according to Fig. Figure 2a shows a plate 2 made of an inorganic glass, for example, quartz glass. The plate 2 is, for example, 200 µm thick. First converter particles 3 are arranged on the plate 2. The first converter particles 3 consist of a core 3b and a shell 3a. The core 3b consists of a nitride phosphor with the formula M2SiN8:Eu 2+with M = Ca, Sr, Ba or mixtures thereof and emits light in the red wavelength range of the electromagnetic spectrum. The shell 3a consists, for example, of AlN. When the first converter particles 3 are applied to the molten surface layer of the first main surface 2a of the plate 2, the first converter particles 3 do not sink in. It is possible that some first converter particles 3 partially sink into the molten surface layer, so that they are partially embedded in the plate 2. Second converter particles 7 are arranged in the plate 2 and completely embedded in the inorganic glass. The second converter particles 7 consist of an oxide phosphor, for example YAG. A protective layer 4 is arranged on the first main surface 2a of the plate 2. The protective layer 4 consists, for example, of parylene. The protective layer 4 is, for example, 40 µm thick.It completely covers the first converter particles 3, so that the first converter particles are in direct mechanical contact with the inorganic material of the platelet 2 and / or the protective layer 4. The first converter particles 3 thus have no contact with the ambient air. Alternatively, no second converter particles 7 may be present in the conversion element 1.

[0091] The conversion element 1 according to Fig. 2b shows in comparison to the conversion element in Fig. 2a, that the first converter particles 3 are partially embedded in the inorganic glass of the plate 2. The first converter particles 3 have thus partially sunk into the molten surface layer of the first main surface 2a of the plate 2 during the manufacturing process. Alternatively, no second converter particles 7 may be present in the conversion element 2.

[0092] The optoelectronic component 5 according to Fig. 3 shows a carrier 8 with a lead frame 9. A layer sequence 6 is arranged on the carrier 8 and is electrically connected to the lead frame 9 via bonding wires 10. A conversion element 1 is mounted above the layer sequence 6. The conversion element 1 corresponds to a conversion element 1 that is used in the Fig. 1a, Fig. 1b, Fig. 2a or Fig. 2b. The conversion element 1 from the Fig. 1a to 2b can be arranged such that the first 2a or second main surface 2b of the platelet 2 faces the layer sequence 6. Preferably, in the case of conversion elements 1 according to Fig. 2a and Fig. 2b the second main surface 2b of the layer sequence 6 faces. If the conversion element 1 of the Fig. 1a to 2b, an antireflective and / or reflective layer (not shown) is applied to the conversion element 1, which is arranged such that the second main surface 2b of the platelet 2 faces the layer sequence 6. The conversion element 1 is arranged in the beam path of the electromagnetic primary radiation emitted by an active layer (not shown separately here) in the layer sequence 6. The conversion element 1 is stable against temperature, humidity, and radiation exposure. It does not cloud, or only slightly, and does not yellow, or only slightly. This ensures that the luminous efficacy is not reduced, or only slightly reduced, and the emission characteristics of the optoelectronic component 5 are not changed, or only slightly changed. An antireflective and / or reflective layer can have a bandpass or edge filter characteristic and be transparent (antireflective) to the primary radiation and reflective to the secondary radiation.

[0093] Additionally, an adhesive layer (not shown here) can be applied between the layer sequence 6 and the conversion element 1. The adhesive layer can comprise silicone, for example.

[0094] Preferably, the optoelectronic component 5 is an LED, wherein the radiation is coupled out upwards in the figure via a transparent layer sequence 6 and the conversion element 1.

[0095] The optoelectronic component 5 according to Fig. Figure 4 shows a carrier 8 with a lead frame 9 and a housing 11. The housing 11 has a recess in the center in which the layer sequence 6 is arranged, which is electrically connected to the lead frame 9. The recess is filled with a potting compound 12. The potting compound 12 comprises, for example, a silicone or epoxy.

[0096] A conversion element 1 is arranged above the recess of the housing 11 and the housing 11. The conversion element 1 is arranged in the beam path of the electromagnetic primary radiation emitted by an active layer (not shown separately here) in the layer sequence 6.

[0097] The conversion element 1 corresponds to a conversion element 1 that is in the Fig. 1a, Fig. 1b, Fig. 2a or Fig. 2b is shown.

[0098] Additionally, an adhesive layer (not shown here) can be applied between the housing 11 and the conversion element 1, and between the encapsulation 12 and the conversion element 1. The adhesive layer can comprise silicone, for example.

[0099] Preferably, the optoelectronic component 1 is an LED, wherein the radiation is coupled out upwards in the figure via a transparent layer sequence 6, a transparent encapsulation 12 and the conversion element 1.

Claims

[1] Conversion element (1) - with a plate (2) comprising an inorganic glass, - with first converter particles (3), whereby - the first converter particles (3) have a shell (3a) and a core (3b), - wherein the shell (3a) comprises an inorganic material and has a thickness of between at least 10 nm and at most 50 µm, and - the core (3b) comprises a nitride or oxynitride phosphor and - wherein the first converter particles (3) are arranged on and / or in the platelet (2). [2] Conversion element (1) according to claim 1, wherein the inorganic material of the shell (3a) is selected from a group comprising SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene and combinations thereof. [3] Conversion element (1) according to one of the preceding claims, wherein a protective layer (4) is arranged above the platelet (2), which protective layer comprises a material selected from a group comprising parylene, polysilazane, silicone, SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene, an inorganic glass and combinations thereof. [4] Conversion element (1) according to claim 3, wherein the first converter particles (3) are completely embedded in the inorganic glass of the plate (2) or completely embedded in the inorganic glass of the plate (2) and the material of the protective layer (4). [5] Conversion element (1) according to one of the preceding claims, which comprises second converter particles (7) which comprise an oxide phosphor. [6] Conversion element (1) according to claim 5, wherein the second converter particles are arranged on and / or in the platelet (2). [7] Conversion element (1) according to one of the preceding claims, wherein a chemical bond exists between the inorganic material of the shell (3a) of the first converter particles (3) and the inorganic glass of the platelet (2). [8] Conversion element (1) according to one of the preceding claims, wherein the inorganic glass is a silicate glass, a borate glass or a phosphate glass. [9] Method for producing a conversion element (1) comprising the method steps A) coating particles of a nitridic or oxynitridic phosphor with an inorganic material selected from a group comprising SiO2, TiO, TiO2, Al2O3, B2O3, ZrO, ZrO2, ZnO, ZnO2, an inorganic-organic hybrid material, AlN, BN, TiN, Si3N4, ZrN, Zn3N2, graphene and combinations thereof to form first converter particles (3) which have a shell (3a) made of the inorganic material and a core (3b) made of the nitridic or oxynitridic phosphor, wherein the shell (3a) has a thickness of between at least 10 nm and at most 50 µm, B) Providing a plate (2) consisting of glass, C) melting a surface layer of the plate (2), E) Applying the first converter particles (3) to the melted surface layer. [10] Method according to claim 9, wherein, when applying the first converter particles (3) to the molten surface layer in method step E), the shell (3a) of the first converter particles (3) comes into contact with the molten surface layer and is molten. [11] Method according to one of claims 9 to 10, wherein after method step E) a further method step takes place: F) Partial and / or complete sinking of the first converter particles (3) into the molten surface layer. [12] Method according to one of claims 9 to 11, wherein after method step C) two further method steps take place: D) applying second converter particles (7) comprising an oxide phosphor to the melted surface layer, D1) allowing the second converter particles (7) to sink completely into the molten surface layer. [13] Method according to one of claims 9 to 12, wherein a slip or a gel comprising the inorganic material or the inorganic material in a gaseous state is used to coat the particles of the nitridic or oxynitridic phosphor in method step A). [14] Optoelectronic component (5) comprising - a layer sequence (6) with an active layer which emits electromagnetic primary radiation during operation of the component, - at least one conversion element (1) according to one of claims 1 to 8, which is arranged in the beam path of the electromagnetic primary radiation and above the layer sequence (6), wherein - the first converter particles (3) at least partially convert the electromagnetic primary radiation into electromagnetic secondary radiation.

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