DE102009010468A1 - Method for manufacturing layer of radiation-emitting functional material arranged with light conversion material particle for substrate, involves supplying composition, which contains solvent and organic bonding agent - Google Patents

Abstract

The method involves supplying the composition, which contains a solvent and an organic bonding agent. The composition is applied on a layer of the functional material or a substrate (6), which is applied on the radiation-emitting functional material. The organic constituents are removed from the applied composition. Independent claims are included for the following: (1) a substrate with a bond; and (2) an optoelectronic device with a primary light source.

Description

The The present invention relates to a method for fixing light-conversion substance particles a layer of a radiation-emitting functional material or a coatable on the radiation-emitting functional material Substrate, a radiation-emitting device, in the beam path the primary light source can be produced by this method Layer of a radiation-emitting functional material with it arranged particles of a light conversion material is arranged and a substrate having light conversion particles fixed thereon.

To The prior art is light conversion particles on radiation-emitting functional materials applied by into an organic matrix (for example from a resin, for example Epoxy or silicone) are introduced; this organic matrix with the light-conversion particles is then applied to the radiation-emitting functional material and cured.

It However, the task is to provide a functional material with it arranged light conversion particles to provide in which the light conversion substance particles or the matrix, the contains these light conversion particles, cheaper are fixed.

These The object is achieved by a method according to claim 1. Further independent claims relate to a substrate with light conversion particles fixed thereon and an optoelectronic Component in which a processable layer of a radiation-emitting functional material with particles arranged thereon a light conversion substance is contained. under claims teach advantageous developments.

With the method according to the invention, the particles of the light conversion substance are fixed on a substrate as follows:
In a first method step (method step (A)), the particles of the light conversion substance are applied in the form of a composition to the radiation-emitting functional material or to a substrate which can be applied to the radiation-emitting functional material. This composition contains, in addition to the particles of the light conversion substance, a solvent and / or an organic binder. Alternatively, the composition may consist of the light-conversion substance particles, the solvent and / or the organic binder. The arrangement can be done with any method; However, it is useful to carry out this step so that a homogeneous distribution of the light-conversion substance particles takes place on the functional material / substrate, so that the desired conversion effect is achieved in a radiation-emitting device.

In a process step (B) is then the composition thus applied Subjected to conditions in which the organic constituents the composition are removed. The removal of the organic Ingredients can be done in any way; In particular, conditions are to be mentioned in which the organic Material burned out and / or evaporated. Frequently becomes the process step (B) therefore the application of a vacuum and / or the introduction into an oven for combustion and / or evaporation of the organic ingredients. Such a furnace usually becomes be operated at temperatures of maximum 400 ° C, so that neither damage a temperature-sensitive Substrate still an impairment of the conversion effect the light conversion substance particles is to be feared.

In a further process step (process step (C)) the light conversion particles on the functional material / substrate either chemically fixed and / or (directly) physically on the functional material / substrate fixed. Finally, if necessary, the application of the thus obtained substrate on the radiation-emitting functional material

in the Under this invention, the two alternatives, according to which the particles of the light conversion substance either on the functional material or a coatable on the radiation-emitting functional material Substrate applied are also referred to as functional material / substrate.

When radiation-emitting functional material can be any material used in a radiation-emitting device, be used. For example, semiconductor layers contained in an LED to call. This functional material can also be the topmost layer one composed of several layers, in the radiation-emitting Device be included primary light source.

For the substrate which can be applied to the light-emitting functional material Any material is suitable. As a rule, however, a substrate is used which ensures that the primary radiation a primary light source for the particular application desired spectral range is not absorbed. To call For example, quartz glass and sapphire substrates.

With the method according to the invention, it is possible to fix the conversion substance particles to ensure high mechanical strength on the substrate.

By the fixation due to the removal of the organic components the composition is essentially inorganic in nature, it is possible, light conversion particles also for applications where the use of organic materials is critical is because they are not sufficiently resistant to radiation (eg high-power LEDs or LEDs with emission in the UV range). In particular, the problem is playing discoloration of the organic matrix is not important. There are in radiation-emitting devices also no age-related Loss of efficiency as with the use of organic materials to be expected as a fixative.

After all is a very with the inventive method precise arrangement of the light conversion particles on the functional material / substrate possible.

One Bleeding of the matrix material containing the light conversion substance particles therefore does not matter. In contrast, by bleeding In organic matrix materials such as silicone often one Contamination of the bond pads of LED's; these will but needed for contacting the chip, so that a contact is not possible or at least is difficult.

The solvent used for the composition is preferably chosen so that the conversion substance-particle-solvent mixture with common methods (eg printing process or sedimentation process) can be applied to the substrate. Preference is given here Solvents that are an agglomeration tendency of the conversion substance particles do not promote or even cause deagglomeration. In particular, alcohols (for example isopropanol or 1,4-butanediol) or water.

When Organic binders are all binders that are among the said conditions substantially residue-free removable are. Furthermore, binders are suitable which have a deagglomeration support the conversion substance particles used. In particular, commercial binders are in this case too call that a good dispersion of ceramic particles and ensure good processability of the slip obtained, for example Acrylate-based binders. Furthermore, the organic binder should ensure that it contains conversion substance particles even after the removal of the organic components well on the Substrate / functional material are fixed. These binders can also additives to further improve the processability contained (eg defoamers or plasticizers).

• – Chlorosilikate wie beispielsweise in der DE 100 36 940 und dem dort beschriebenen Stand der Technik offenbart,
• – Orthosilikate, Metallsulfide, Thiogallate und Vanadate, wie beispielsweise in der WO 2000/333 90 und dem dort beschrieben Stand der Technik offenbart,
• – Aluminate, Oxide, Halophosphate, wie beispielsweise in der US 6,616,862 und dem dort beschrieben Stand der Technik offenbart,
• – Nitride, Sione und Sialone wie beispielsweise in der DE 101 47 040 und dem dort beschriebenen Stand der Technik offenbart und
• – Granate von Yttrium und/oder den seltenen Erden wie YAG:Ce und der Erdalkalielemente wie beispielsweise in der US2004/0626999 und dem dort beschriebenen Stand der Technik offenbart.

For the light conversion particles are all known for use in LEDs conversion materials. Examples of such suitable as conversion substances phosphors and phosphor mixtures are:

• - Chlorosilicates such as in the DE 100 36 940 and the prior art described therein,
• - Orthosilicates, metal sulfides, thiogallates and vanadates, such as in the WO 2000/33390 and the prior art described therein,
• Aluminates, oxides, halophosphates, such as in the US 6,616,862 and the prior art described therein,
• - Nitrides, Sione and Sialone such as in the DE 101 47 040 and the prior art disclosed therein, and
• - Garnets of yttrium and / or the rare earths such as YAG: Ce and the alkaline earth elements such as in the US2004 / 0626999 and the prior art described therein.

The said light conversion materials are usually present as powder of light conversion material particles. The size of the light conversion substance particles is usually 1 to 20 .mu.m, preferably 2 to 15 .mu.m. The average particle size d ₅₀ is usually between 2 and 10 microns.

In an embodiment of the invention Process become in process step (C) the light conversion material particles on the functional material / substrate either with an inorganic fixative chemically fixed and / or (directly) physically fixed. The fixation takes place in such a way that at a physical fixation at least partially a cohesive connection of the particles with each other and with the functional material on the one hand or with the substrate arises on the other hand. In a chemical fixation takes place (by means of the inorganic fixative) a cohesive Connecting the light conversion material particles with each other and / or with the functional material on the one hand or the substrate on the other.

Under chemical fixation with an inorganic fixative understood here that between fixative and conversion substance particles and optionally also between substrate / functional material and Fixative chemical bonds or interactions be formed so that (by means of the inorganic fixative) a cohesive connection of the particles with each other and / or with the substrate / functional material.

at This chemical fixation can also be a change of chemical structure of the fixative done; a change However, the chemical structure of the conversion substance particles should, if at all, only take place in the area of the surface of these particles.

On the other hand can be a physical fix without an additional (Inorganic) fixative done by energy in the System light conversion substance particles / substrate is registered. By The energy input then forms chemical bonds or interactions (between substrate / functional material and conversion substance particles) out.

The Functional material or Substrate and the inorganic fixative used for fixation are usually made of different materials. For the Inorganic fixatives are basically any Material suitable. As a rule, however, a material is used which ensures that the primary radiation a primary light source for the particular application desired spectral range not or only in small Extent is absorbed. Furthermore, the functional material should no damage to the light conversion particles (i.e. H. in particular, no impairment of their conversion effect) cause.

The Method according to this embodiment allows due the inorganic fixative a very precise arrangement the light conversion material particles and the inorganic fixative on the functional material / substrate. The particles of the light conversion substance are usually statistically distributed on the functional material / substrate in front. Bleeding this fixative occurs - different than when using silicone resin-based organic fixatives - not on.

The Ratio of light-conversion particles and inorganic Fixing agent can be adjusted arbitrarily. Especially are ratios between 5% by volume of inorganic fixative and 95% by volume of light conversion particles and 90% by volume of fixative and 10 vol .-% light conversion particles useful. Prefers the proportion of light-conversion substance particles is at least 40 Vol .-%, more preferably at least 50 vol .-% on.

Becomes the proportion of the inorganic fixing agent is too high, thus, the conversion efficiency of the conversion substance / fixative mixture reduced compared to the pure conversion substance particles be.

Of the Proportion of the inorganic fixing agent is preferred at least 10 percent, more preferably at least 25 percent. From such a proportion is with good mechanical stability of the conversion substance particle / fixative / substrate or conversion substance particle / fixative / functional material system to count.

The Ratio between inorganic fixative and Light conversion particles can also be chosen that after chemical fixation, the conversion substance particles not completely in the inorganic fixative are embedded. Rather, it is usually sufficient that the uppermost layer of light-conversion particles only in the range their respective functional material side facing the inorganic fixative is firmly bonded. So is it intended only a monolayer of the light-conversion substance particles on the functional material / substrate to fix, it follows that the inorganic fixative a reduced compared to the light conversion particles Particle size should have. Is the layer thickness the fixed light conversion particles compared to the mean size of the light conversion particles z. B. increased 2 to 20 times, it follows that - assuming that the inorganic fixing agent is in powder form and the powder particle form is essentially preserved - the Particle size of the particles of the inorganic fixative opposite the light conversion substance should preferably be reduced in size and In addition, the proportion of the inorganic fixative 30 to 60 vol .-%, preferably 40 to 50 vol .-% should be. In this case, too Then the light conversion particles of the uppermost layer at least partially from the conversion substance particle / fixative mixture protrude.

A complete embedding of the light conversion substance particles but in a matrix of the inorganic fixative can also be desired. If this is the case, then in particular a protection of the sensitive light conversion particles Moisture and oxygen take place. Such a protective effect can be used in light-conversion particles in an organic Matrix present, z. B. due to aging phenomena (eg. Embrittlement) of the matrix or else due to the chemical Composition of the matrix does not exist.

The composition provided in process step (A), which comprises conversion substance particles, solvent / organic binder and optionally an inorganic fixative, can be applied to the functional material / substrate by any desired method. The composition may be, for example, by means of printing processes such as screen printing and sieving pressure-like methods, spraying, coating methods such as dip coating and spin coating, jet printing or knife coating or Aufededimentieren are applied and is therefore usually designed such that it can be applied by one or more of these methods.

In In another embodiment of the invention, the mixture is the conversion substance particle, binder / solvent and optionally an inorganic fixative, as about 3 to 300 microns thick layer, preferably 10 to 50 microns thick Layer applied (based on the final layer thickness after fixing, in particular after a sintering process). For purely physical Fixation of the conversion substance particles is the final layer thickness usually 3 to 50 μm; with chemical fixation by means of an inorganic Fixing agent is usually 5 up to 150 μm. The layer thickness is measured here in particular the particle size of the conversion substance particles and the conversion effect to be achieved, d. H. according to the desired Color impression of the secondary radiation or the Proportion of the primary radiation to be converted in one optoelectronic component. Furthermore, the layer thickness also becomes influenced by the type, proportion and properties of the conversion substance.

In In another embodiment, the physical and / or chemical fixation of the light conversion substance particles on the functional material / substrate by means of a sintering process. The sintering process is carried out so that in the physical fixation bonds or interactions between functional material / substrate and light conversion substance particles form, in chemical fixation bonds or Interactions between fixative and conversion substance particles and optionally also between functional material / substrate and Training fixative.

In In one embodiment, the sintering process is performed that no complete melting of the inorganic Fixing agent takes place. The sintering process is then preferred at a temperature below the melting point of the inorganic Fixing agent performed. In a further embodiment the sintering process is carried out in such a way that between the particles of the inorganic fixative with each other or with the light conversion substance particles and the Functional material / substrate just as many bonds / interactions be formed that a cohesive connection is given or - in the physical fixation - straight a cohesive connection between conversion substance particles and functional material / substrate is given (in this case comes So it - if anything - only one Melting the particle surface of the inorganic fixative). Fully melts the inorganic fixative This can lead to the conversion effect the melt embedded (or even dissolved) Light conversion substance particles is significantly deteriorated.

In Another embodiment is the sintering method so performed that no melting of the conversion substance particles takes place or that at best a melting of the surface the conversion substance particle takes place. As a rule, therefore the melting point of the inorganic fixative below that of the Light conversion material. When using an inorganic fixative Further, the type and amount of the inorganic fixing agent and the sintering temperature preferably chosen so that no eutectic Melting of the mixture of the inorganic fixative and the conversion substance particles takes place. Both aforementioned embodiments can therefore serve to prevent the conversion effect the melt-embedded light-conversion particles deteriorated.

To The sintering method described above can in particular a coated functional material / substrate are obtained, in which - provided a chemical fixative is used - between the sintered Lichtkonversionsstoff- and fixative particles Cavities and / or spaces are formed. Such a coated functional material / substrate therefore decreases mostly in the sintered and unsintered state substantially the same space (the density change of the layer Conversionsstoffpartikeln and optionally contained inorganic Fixing agent is then usually a maximum of + 10%). The sintering process can also be carried out so that the resulting structure has an open-porous structure. The volume occupied by the inorganic fixative is Proportion of the existing cavities, in particular 2 to 35 Vol .-%, often 5 to 20 vol .-%. Incidentally, results from the above-described sintering process, that in Presence of a porous structure, the cavities / pores usually substantially homogeneous over the sintered inorganic Fixing agents are distributed. However, by sedimentation phenomena the proportion of cavities on the functional material facing side of the layer of the sintered fixative be diminished.

As a sintering method for physically and / or chemically fixing the light-conversion substance particles on the functional material / substrate, any sintering method can be used. To name a few are, for example, laser sintering methods ren, microwave sintering method or sintering method in which the workpiece to be sintered is introduced into a conventional oven. Particular preference is given to sintering processes in which the energy is introduced into the system of light conversion substance particles, functional material / substrate and optionally contained fixing agent in such a way that targeted heating of the regions where no bonds are to be attached or no interactions are desired is avoided. These are, in particular, the regions of the light conversion substance particles which are not close to the surface and optionally of the functional material. Furthermore, in the fixation of the light conversion substance particles on or by means of a substrate, a continuous (homogeneous) heat distribution is preferred; Sintering in a conventional oven ensures this. When fixing the light conversion substance particles on a functional material, the heat input is generally desired only in the layer containing the light conversion substance particles to be sintered and the lowest possible heat transfer to the functional material; In most cases, therefore, a laser sintering process or a microwave sintering process is used in this case.

Of the Sintering is usually carried out at temperatures <1100 ° C, preferably <800 ° C, particularly preferably <500 ° C.

The selected temperature depends on the sintering process essentially based on what nature of the inorganic fixative is or whether the light conversion substance particles directly (physically) to be sintered with the functional material / substrate and whether sintered on a substrate or on a functional material becomes.

In In one embodiment, the sintering temperature is selected that the sintering temperature below the melting temperature of the inorganic Fixing agent or - in the physical Fixation - the light conversion substance particle is located. As stated above, it is only necessary that the bonds between the particles of the fixative, the functional material / substrate and the light conversion material particles can be formed. Accordingly, usually remain after the sintering process obtained functional material / substrate with fixed light conversion particles the grain boundaries and / or particle boundaries of the previously present Fixing agent and Lichtkonversionsstoff particles substantially visible (and recognizable by means of optical detection methods).

In an embodiment is in the inventive Process as fixing agent a nanopowder and / or a submicropulver, which consists of a ceramic component, used or a mixture containing such a nanopowder and / or submicropulver contains, used. Alternatively or simultaneously also the light conversion substance particles in the form of a nanopowder and / or a Submikropulvers or a share Containing nanopowder and / or submicropulver. In the latter case corresponds to the proportion of nanopowder and / or submicropulver, then preferred for the inorganic fixative above specified.

According to the invention, nanoparticles are understood as meaning particles having an average particle size (d ₅₀ ) of 1 to 100 nm (eg particles having an average particle size between 10 and 40 nm); Submicroparticles in particular have an average particle size between 100 and 1000 nm (in particular between 250 and 800 nm). By using nanoparticles, it is generally possible to reduce the melting point from that of larger particles (in the case of conversion substance particles, eg from YAG, by about 200 ° C.).

SiO ₂ (eg Aerosil) or aluminum oxide can be used as the ceramic component for the nanopowder and / or the submicrop powder.

When Nanopowder / Submikropulver the light conversion particles can For example, garnet powder (about YAG) can be used.

In In another embodiment, the inorganic fixative be a flux or contain a flux. Such a thing Flux has the effect that the melting temperature of the sintered Material can be lowered. This alternative is not only possible, first a mixture of fixative and to produce conversion substance particles; it can also the conversion substance particles coated directly with the flux be so that at least part of the surface with it coated, and then applied to the functional material / substrate become.

In a further embodiment, a mixture having a low eutectic melting point is used as the inorganic fixing agent. For example, the phase diagram of the SiO ₂ / B ₂ O _{3 system has} a eutectic at 372 ° C. From this can z. For example, a composition comprising 80% by volume of a solvent (eg butanediol), 10% by volume of phosphor particles (eg YAG) and 10% by volume of the components of the low-melting system (of 33 mol% SiO ₂ and 67 mol% B ₂ O ₃ ). Furthermore, a mixture of nano-boron nitride with various inorganic oxides should be mentioned as a low-melting system (this is available, for example, from the company ItN / Nanovation GmbH under the name Nanocomp PP MT 11).

Here, the eutectic mixture of the two components (eg., SiO ₂ / B ₂ O ₃₎ is preferably melted before the mixture with the light conversion material particles together and then used in powdered form as a fixing agent.

In In another embodiment, the inorganic Fixing means of a ceramic material and / or a glass or contains one (or both) of the mentioned Substances.

According to one embodiment, suitable glasses are in particular the substances in which the SiO ₂ content is the main component and in particular> 50% by weight. Other components which may be used are acidic oxides, in particular acidic oxides of composition A ₂ O ₃ , AO ₂ and A ₂ O ₅ - where A is any oxide-forming element (eg B ₂ O ₃ , Al ₂ O ₃ , GeO ₂ , TiO ₂ , P ₂ O ₅ ). Furthermore, basic oxides may be present (eg Na ₂ O, K ₂ O, MgO, CaO, PbO, ZnO, BaO, Li ₂ O). Finally, substances such. For example, fluorides may be contained in the glass.

Especially Glases used are preferably low-melting types of glass. Although lead-containing glasses have a relatively low melting point however, are less preferred because lead is a heavy metal in disposal issues. For setting a low melting point also components that act as fluxes in the Glass (for example, the said zinc oxide and the above Alkali oxides).

The commercially available glass particles exhibit for the inventive method often large particle sizes. In a preferred embodiment Therefore, the standard glasses before the Milled as an inorganic fixative (eg with a Ball mill or a planetary ball mill) to reduce the particle size. Preferred middle Particle sizes are between 0.1 and 20 microns. Particularly preferred are average particle sizes between 0.1 and 2 μm. It is further preferred that the mean size of the glass particles (respectively ceramic particles) is smaller than that of the light conversion substance particles. Farther can mixtures of different particle sizes be used.

The Relationship between glass particles and the particles of the Light conversion substance (in Vol .-%) is above for the inorganic fixatives generally indicated. Prefers is the ratio of glass particles / light conversion particles between 60/40 and 10/90 vol .-%, particularly preferably it 55/45 to 30/70 Vol .-%. Furthermore, it was found that for particle mixtures, in which about the same amount (in Vol .-%) of glass particles and Light conversion particles are present, a lowering of the Temperature needed to sinter the particles to be recorded. Very particular preference is therefore a particle ratio Glass particles / light conversion particles between 50/50 and 45/55 Vol .-%.

The Glass particles are used (mixed with the light-conversion particles) preferably in the form of a slip composition on the functional material / substrate applied, in addition to the particles a solvent contains (for example, have as suitable an alcohol such as butanediol and water exposed).

In Another embodiment is prior to process step (A) the inorganic fixing agent (optionally in a solvent or organic binder) on the functional material / substrate applied. This process variant is suitable for all the aforementioned fixative. It is particularly suitable when applied to a monolayer of light-conversion particles shall be. However, multi-layered light-conversion material particles can also be used be applied, then is preferred before the process step (A) applied intermediate layer of fixing agent and optionally existing solvent or binder chosen so that a subsidence of the light conversion substance particles in this intermediate layer is possible.

In a further embodiment, the conversion substance particles are used up on the functional material / substrate by means of a sol-gel material as an inorganic fixative. Alternatively, a layer of the light-conversion substance particles produced by method step (A) (or optionally also (B)) may also be subsequently impregnated with a mixture of the precursors of the sol-gel material (optionally with a solvent). The inorganic fixing agent may in this embodiment be, for example, a precursor of the respective light conversion substance. If, for example, YAG: Ce is used as the light conversion substance, the inorganic fixing agent may be a mixture of yttrium acetate, aluminum acetylacetonate and cerium acetylacetonate (for the Ce doping). Here, the fixation of the light conversion material particles is achieved by reacting or precursors (which are in particular organometallic compounds or metal salt solutions) during the temperature treatment to form oxides. In this case, then (nano) conversion particles and / or (nano) particles of at least one inorganic fixing agent, the latter being selected in particular from the groups indicated above and therefore usually case has no light-converting properties.

In In another embodiment, the light conversion material particles be fixed on the functional material / substrate by the chemical Fixation by means of a fixative, by a sputtering process is applied takes place. The functional material / substrate on which according to process step (A) the light conversion substance particles are then exposed to a sputtering, at a coating with ceramic material and / or with glass takes place and in which these (serving as an inorganic fixative) Substances in the cavities between the particles of the light conversion substance be stored.

In In another embodiment, the particles the light conversion substance on the functional material / substrate fixed be on the functional material / substrate on the according to process step (A) the light conversion particles are arranged, a fixation by means of a fixative produced by Chemical Vapor Deposition (CVD) or a similar method is applied takes place.

The According to the invention used layer of a radiation-emitting functional material is in particular a constituent the primary light source of an optoelectronic component, in particular a light emitting diode, a laser diode or a photodiode. As a rule, this component is the semiconductor for generating the primary radiation. In the fixation of the conversion substance particles It should then be noted on this functional material that the fixing conditions do not lead to damage to the semiconductor. In particular, the sintering temperature should therefore only as high as absolutely necessary to get voted.

Around Also, to prevent damage to the semiconductor a substrate with the conversion substance particles on the semiconductor be applied in the beam path of the primary light source. For example, the substrate may contain conversion substance particles The primary light source can be arranged by an adhesive between primary light source and substrate (with conversion substance particles) is introduced to a fixation of the substrate with the conversion substance particles to ensure on the primary light source.

In an alternative embodiment can also over the inorganic fixing agent cohesively with each other Connected conversion particles without a substrate in the beam path of the Primary light source are introduced. The substrate in process step (A) is then to be chosen so that during the fixation process (For example, under the conditions during a sintering process prevail) to the substrate no material connections from the conversion substance particles on the one hand and from the particles of the inorganic fixative, on the other hand. When Substrate come in this embodiment, in particular substrates from Al 2 O 3 (in particular from corundum), boron nitride or tungsten into consideration. Also, glasses may be suitable, provided that have a correspondingly high melting point.

The after removal of the substrate obtained layer of material fit interconnected particles of the inorganic fixative and the light conversion substance particles can then - as before for the substrate with light-conversion particles - in the beam path of the primary light source of an optoelectronic Component be introduced. Due to the lower mechanical Stability of such a layer is preferred, these Layer directly on the primary light source (ie eg in Semiconductor) and optionally by means of an adhesive to fix on it.

If the substrate is not removed from the layer of particles of the inorganic fixing agent and the light conversion substance particles, the transparent substrates are glasses which have a higher melting point than the inorganic fixing agent and Al ₂ O ₃ substrates (eg sapphire) and Zinc oxide substrates z. As quartz glass (depending on the fixative used).

With the method according to the invention can be a functional material / substrate with particles arranged thereon of a light conversion substance. For this functional material / substrate the light conversion substance particles are cohesive connected to each other and / or with the functional material / substrate; the cohesive connection takes place here partially or (preferably) completely via inorganic Bonds.

Under a compound via inorganic bonds is hereby understood that the cohesive connection does not have over chemical structural elements take place in which hydrocarbon groups (as a linking component or as a side chain) are.

The grain boundaries / particle boundaries between the formerly present particles of the light conversion material on the one hand and the optionally contained inorganic fixative on the other hand are substantially visible (ie, by means of optical means substantially completely detectable) are. In addition, in some process variants, the light conversion substance particles of the uppermost conversion material layer protrude from the conversion out substance particles and the particles of the inorganic fixative layer.

One preferred use of the inventive Process produced, cohesively with each other or with a light material particles connected to a functional material / substrate are optoelectronic components with a primary light source, which emits a primary radiation. In the beam path of the Primary light source then become the inorganic bonded Light conversion particles arranged so that the primary radiation is converted into a secondary radiation. Especially are as optoelectronic components light emitting diodes, laser diodes and to name photodiodes. In the light-emitting diodes is mentioned Arrangement especially for the production of white Light suitable (eg with YAG: Ce or a yellow-emitting orthosilicate as a phosphor).

Further Features, advantages and advantageous embodiments arise - without Restriction of generality - from the following Description of the embodiments and the figures.

1 shows a schematic cross section of an optoelectronic component, namely an LED.

1 shows an optoelectronic component with a radiation-emitting device. The radiation-emitting device comprises a semiconductor layer sequence as the radiation-emitting functional material 1 that directly with as well as via a connection 2 with a circuit board 7 is contacted. The semiconductor layer sequence is still on the carrier 4 arranged. The semiconductor layer sequence 1 and the carrier 4 are in the cavity 3 a housing 5 , On the semiconductor layer sequence is a substrate 6 arranged thereon with light conversion particles (not shown). The generally one-piece substrate has in the figure a recess for the connection 2 on. If the complete contacting of the back, so no recess is necessary.

The measurement of the particle size distribution and the d ₅₀ values is carried out according to the invention always by means of laser diffraction.

1. Coating a substrate with a Slurry containing light conversion substance particles:

Out 60 to 85% by volume of an acrylic based binder (eg WB4101 the company Polymer Innovations) and 15 to 40% by volume of a doped one Garnets as a light conversion substance (eg YAG: Ce - The particle size of YAG: Ce is between 2 and 10 μm (d50)) a mixture is prepared which, in order to obtain sufficient homogenization to reach about 30 minutes to 4 hours in a roller mill is ground.

are Nanoparticles contained in the mixture, so it is advisable, the Mixture before treatment with the roller ball mill in to handle a speed mixer, so that the formation of agglomerates can be reduced.

Instead of The acrylic-based binder can also be a solvent can be used, for example, butanediol.

Instead of 15 to 40% by volume of pure light conversion particles can also a mixture of light-conversion particles and the inorganic fixative be used in an amount of 15 to 40 vol .-%.

Of the thus obtained slip is applied by means of a doctor blade to a sapphire substrate applied, so that when fresh a layer of about 90 microns Thickness arises.

2. Remove the binder / solvent from the coated substrate.

The obtained according to Example 1 substrate, which with the slip of light-conversion particles and organic binders or solvents and optionally inorganic fixative is coated is first subjected to a drying step, so that the Volatiles evaporate. This drying step usually becomes carried out for several hours to one day. Subsequently becomes the substrate with the light conversion particles placed thereon Subjected to conditions in which an organic binder burned out is and the last residues of remaining solvent disappear. Usually, the burnout of the Solvent in an oven at about 400 ° C. Becomes the coated substrate for fixing the light-conversion particles Subsequent to a sintering process, the removal of the organic binder also occur simultaneously with the sintering.

3. Fix the particles of the light conversion substance

3.1. Physical fixation

A slip of 15-35% by volume of YAG: Ce and an acrylate-based binder is applied to a sapphire substrate as a layer about 90 μm thick. The YAG: Ce used here has a particle size d ₅₀ of about 2 μm. The slurry coated substrate is now sintered at 1300 ° C for 180 to 240 minutes. In order to prevent oxidation of Ce ³⁺ to Ce ⁴⁺ is under inert gas or worked in a reducing atmosphere. A separate burnout of the binder does not take place; the binder is removed during the sintering process.

It becomes a layer with a thickness between 20 and 35 μm receive.

through a commercial adhesive tape for bonding paper (eg, the Tesa brand) becomes the bond of the light-conversion particles checked on the substrate. The tape will on the entire surface with the light conversion particles pressed substrate coated and subsequently removed so the pulling direction is perpendicular to the substrate plane. This Test is hereinafter referred to as "sticking test".

On The peeled tape can not light-conversion particles be detected.

3.2. Fixation by using a Slip with nanoparticles:

On a sapphire substrate, a slurry of 80 vol .-% organic binder, 19.5 vol .-% YAG and 0.5 vol .-% nanodispersed SiO ₂ (Aerosil) is applied as a layer with a thickness of 90 microns. After drying, the coated substrate is sintered at 1100 ° C in an oven.

At the Adhesive test can not be a conversion substance particles on the tape prove. Compared to (purely) physical sintering Thus, the sintering temperature can be lowered by about 200 ° C.

3.3. Fixation by using a Slurry with a sintering aid with low eutectic melting point

A slip having the following composition is produced: 94% by volume of organic binder, 0.5% by volume of nanodispersed SiO ₂ (Aerosil), 2.5% by volume of nanodispersed boron nitride (from ItN / Nanovation GmbH), 3 Vol .-% YAG.

To the drying is carried out a sintering process as in Example 3.2; the sintering temperature is 800 ° C.

At the Adhesive test could - due to the properties of boron nitride - light conversion particles be detected on the adhesive strip. Compared to the (pure) physical sintering can reduce the sintering temperature by about 500 ° C are lowered.

3.4. Fixation by using a Schlickers with glass powder:

• (i) A slurry is prepared which consists of 80% by volume 1,4-butanediol, 10% by volume YAG: Ce ³⁺ (d ₅₀ about 2 μm) and 10% by volume of the special glass 10181 from Ferro-GmbH (Constituents: ZnO, Na ₂ O, B ₂ O ₃ , SiO ₂ , d ₅₀ about 1 μm, transformation temperature 433 ° C, start of softening 530 ° C, density 3.47 g / cm ³ ). The mixture is homogenized for 2 hours in a ball mill. The finished slurry composition is knife-coated onto a sapphire substrate as a 90 μm thick layer and dried. The mixture is then sintered for 240 minutes at a temperature of 500 ° C. Thereafter, the layer adheres to the sapphire substrate in such a way that no significant detachment of light conversion substance particles can be detected during the adhesive test.
• (ii) A slurry is prepared which consists of 70% by volume 1,4-butanediol, 15% by volume YAG: Ce ³⁺ (d ₅₀ about 2 μm) and 15% by volume of the special glass 501052 from Ferro-GmbH (Constituents: ZnO, Na ₂ O, Al ₂ O ₃ , B ₂ O ₃ , SiO ₂ , d ₅₀ about 1 μm, transformation temperature 400 ° C, softening start 510 ° C, density 3.341 g / cm ³ ). Homogenization and application of the layer to the sapphire substrate is carried out as in Example 3.4. (I). After drying by evaporation of the solvent, the layer consists in each case of 50% by volume of YAG: Ce and glass. The sintering takes place at 500 ° C for 240 minutes. Thereafter, the layer adheres to the sapphire substrate in such a way that no significant detachment of light conversion substance particles can be detected during the adhesive test.
• (iii) A slurry is prepared which consists of 70% by volume of 1,4-butanediol, 18% by volume of YAG: Ce ³⁺ (d ₅₀ about 2 μm) and 12% by volume of special glass 501052 from Ferro-GmbH consists. Homogenization and application of the layer to the sapphire substrate is carried out as in Example 3.4. (I). After drying by evaporation of the solvent, the layer of 60% by volume consists of YAG: Ce and 40% by volume of glass. The sintering takes place at 6000 ° C for 240 minutes. Thereafter, the layer adheres to the sapphire substrate in such a way that no significant detachment of light conversion substance particles can be detected during the adhesive test.
• (iv) A slurry is prepared consisting of 75% by volume of water, 12.5% by volume of the chlorosilicate phosphor Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ and 12.5% by volume of the special glass 501052 of the Ferro GmbH exists. Homogenization and application of the layer to the sapphire substrate is carried out as in Example 3.4. (I). After drying by evaporation of the solvent, the layer consists in each case to 50% by volume of chlorosilicate phosphor and glass. The sintering takes place 240 minutes in a slightly reducing atmosphere at 450 ° C. Thereafter, the layer adheres to the sapphire substrate so that the adhesive test no significant detachment of Lichtkon version material particles is recognizable.

Across from The (pure) physical sintering can be fixed by use a slip with glass powder so the sintering temperature at least 800 ° C are lowered.

2 shows emission spectra of a layer according to the invention on a sapphire substrate and the influence of the glass fraction on the relative intensity of the luminescence under 460 nm excitation. The layer consists of the chlorosilicate phosphor Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ and the special glass 501052 from Ferro GmbH and was sintered at 500 ° C. for 45 minutes. The invention is not limited by the description with reference to the embodiments. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the patent claims or exemplary embodiments.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10036940 [0017]
• WO 2000/33390 [0017]
• - US 6616862 [0017]
• - DE 10147040 [0017]
• US 2004/0626999 [0017]

Claims (15)

Method for producing a layer of a radiation-emitting Functional material having thereon particles of a light conversion substance, with the following steps: (A) providing a composition the particles of the light conversion substance and a solvent and / or an organic binder and applying the composition on the layer of functional material or a coatable on the radiation-emitting functional material substrate (B) Removal of the organic components from the so applied composition, (C) fixing the particles of the Lichtkonversionsstoffs on the radiation-emitting functional material or on the substrate, which subsequently on the functional material is applied. Method according to the preceding claim, characterized characterized in that the fixing of the light conversion substance particles in process step (C) takes place physically, so that at least partially a cohesive connection of the particles with each other and arises with the functional material or with the substrate. Method according to one of the preceding claims, characterized in that the fixing of the light conversion substance particles in process step (C) chemically by means of an inorganic fixative takes place, so that at least partially a cohesive Connection of the particles with each other arises and / or with the Functional material or the substrate is formed. Method according to one of the preceding claims, characterized in that the light conversion material particles or the composition by means of a screen printing process, a Screen printing-like process, spraying, dip coating, Spin coating, jet printing or applied by knife coating becomes. Method according to one of the preceding claims, characterized in that the physical and / or chemical Fixation of the light conversion substance particles by means of a sintering process, in particular at temperatures ≤ 1100 ° C, preferably ≤ 800 ° C, particularly preferably ≦ 500 ° C takes place. Method according to one of the preceding claims 3 to 5, characterized in that the fixing means of a Nanopowders and / or a submicrop powder of a ceramic component consists of or contains and / or the light conversion particles at least partially present as nanopowders and / or submicropulver. Method according to one of the preceding claims 3 to 6, characterized in that the composition as a fixing agent additionally contains a flux and / or the Particles are at least partially coated with a flux. Method according to one of the preceding claims 3 to 7, characterized in that the fixing means of a ceramic material and / or a glass or one of these Contains substances. Method according to one of the preceding claims 3 to 8, characterized in that before process step (A) the fixative on the layer of functional material or the substrate is applied. Method according to one of the preceding claims 3 to 9, characterized in that the fixation of the light conversion material particles by subsequent coating with a sol-gel material or by sputtering a ceramic material serves as a fixative. Method according to one of the preceding claims, characterized in that the the layer of the functional material a component of the primary light source of a light emitting diode, a laser diode or a photodiode, in particular a layer a semiconductor, is. Substrate with particles arranged thereon Lichtkonversionsstoffs, in which the Lichtkonversionsstoffpartikel cohesively with each other and connected to the substrate are, wherein the cohesive connection partially or completely via inorganic bonds. Method for producing a layer of a radiation-emitting Functional material having thereon particles of a light conversion substance, with the following steps: (A) providing a composition the particles of the light conversion substance and a solvent and / or an organic binder and applying the composition on one on the radiation-emitting functional material applicable substrate, (B) Removal of the organic components from the composition so applied, (C) fixing the Particles of the light conversion substance by means of an inorganic Fixing agent, so that at least partially a cohesive Connection of the particles arises with each other; Replacing the Layer of radiation-emitting light-conversion substance particles and inorganic fixative from the substrate; apply the layer thus obtained on the functional material. Layer of radiation-emitting light-conversion substance particles and an inorganic fixative obtainable by a procedure with the following steps: (A) Provide a Composition containing the particles of the light conversion substance as well contains a solvent and / or an organic binder and applying the composition to a substrate, (B) Removal of the organic components from the so applied Composition, (C) fixing the particles of the light conversion substance by means of the inorganic fixative, so that at least partially a cohesive connection of the particles with each other arises; Peeling off the layer of radiation-emitting Light conversion particles and inorganic fixative from the substrate. Optoelectronic component with a primary light source, which emits a primary radiation and in the beam path the primary light source arranged particles of a light conversion material, the primary radiation into a secondary radiation convert, wherein the device with the method according to claim 1 to 11 or 13 producible layer of a radiation-emitting Functional material having thereon particles of a light conversion substance contains.