Radiation-emitting optoelectronic device and method for producing a radiation-emitting optoelectronic device

Abstract

Radiation-emitting optoelectronic device - comprehensive - a housing body (1), - at least one optoelectronic radiation-emitting semiconductor (2), - a radiation-transparent element (3) different from the housing body (1), - wherein the housing body (1) surrounds at least one optoelectronic radiation-emitting semiconductor (2) at least partially, - wherein the radiation-transparent element (3) is arranged in the beam path of the radiation-emitting semiconductor (2), and - wherein the radiolucent element (3) comprises a fluoropolymer and - wherein the housing body (1) also comprises a fluoropolymer and is in contact with the radiolucent element (3), wherein the housing body (1) and the radiolucent element (3) comprise the same fluoropolymer, wherein the fluoropolymer is a copolymer, comprising a first structural unit A of the following general formula: wherein the substituents X1 to X4 are each independently selected from the group comprising: - Hydrogen, - Halogens, especially F and Cl, - R, - OR, where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be and, where at least one of the substituents X1 to X4 is fluorine, and at least one further second structural unit B, different from structural unit A, of the following general formula: wherein the substituents Y1 to Y4 are each selected independently of one another from the group comprising: - Hydrogen, - Halogens, especially F and Cl, - R - OR where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be or where the structural unit B has the formula.

Description

[0001] The present invention relates to a radiation-emitting optoelectronic device and a method for manufacturing a radiation-emitting optoelectronic device.

[0002] German patent application DE 10 2005 013 785 A1 discloses a light source module and vehicle headlight. German patent application US 2014 / 0138734 A1 describes a module structure. German patent application DE 10 2009 036 622 A1 describes an optoelectronic semiconductor component.

[0003] The object of the invention is to provide a radiation-emitting optoelectronic device that is characterized by particularly high stability and a long service life.

[0004] This problem is solved by a radiation-emitting optoelectronic device according to claim 1. Further embodiments of the device according to the invention, as well as a method for manufacturing a radiation-emitting optoelectronic device, are the subject of further claims.

[0005] The invention according to main claim 1 relates to a radiation-emitting optoelectronic device comprising a housing body (1), at least one optoelectronic radiation-emitting semiconductor (2), and a radiation-transparent element (3) distinct from the housing body (1). The housing body (1) surrounds the at least one optoelectronic radiation-emitting semiconductor (2) at least partially. The radiation-transparent element (3) is arranged in the beam path of the radiation-emitting semiconductor (2) and comprises a fluoropolymer.

[0006] The radiation-transmitting element can be located, for example, in the region of the main radiation-emitting surface of the radiation-emitting optoelectronic device. Fluoropolymers are understood to be, in particular, organic fluoropolymers comprising carbon-fluorine bonds and a backbone consisting of carbon-carbon bonds.

[0007] In conventional radiation-emitting optoelectronic devices, silicones, polymers or glass-like materials are used as radiation-permeable elements in the area of ​​the main radiation emission surface, different from the housing body.

[0008] While glass-like materials exhibit good robustness, they are usually associated with high costs and are complex to manufacture.

[0009] Epoxides and conventional polymers are widely used. However, they each have limited lifetimes. High temperatures, such as those found in many radiation-emitting optoelectronic devices, combined with radiation of at least partially high intensity and energy (for example, short-wavelength blue light with a wavelength of approximately 420 nm or ultraviolet radiation with wavelengths below 410 nm), lead to polymer degradation, i.e., the breaking of covalent bonds in the polymer chains. During operation, this often manifests as yellowing of the radiation-transmitting element and a loss of brightness in the entire radiation-emitting optoelectronic device.

[0010] Radiation-transmitting elements in conventional radiation-emitting optoelectronic devices can still be made of silicones, which, while often more stable than, for example, epoxy-based materials, are nevertheless insufficiently stable for many applications. In particular, they are not sufficiently resistant to high-energy radiation such as ultraviolet radiation.

[0011] The radiation-transmitting element must meet high requirements for transparency or radiation transmittance, not only for visible light but across a broad spectral range. This spectral range can include electromagnetic radiation, such as infrared radiation, visible light, and especially ultraviolet (UV) radiation.

[0012] Due to the high transparency or transmittance of radiolucent elements across a broad spectral range, the radiation emitted by the optoelectronic semiconductor acts on the entire radiolucent element and not just on its surface, as is the case with opaque or even reflective components. This leads to particularly high demands on stability against high-energy radiation such as UV radiation.

[0013] The radiation-emitting optoelectronic devices according to the invention—comprising a radiolucent element containing an organic fluoropolymer—are particularly durable. They also enable a comparatively constant radiation emission over a long operating period because they are significantly less prone to yellowing than conventional polymers. Due to their high stability, no further stabilizing additives are required, which would otherwise pose an additional risk of yellowing.

[0014] Organic fluoropolymers possess an extremely strong CF bond (460 kJ / mol). The fluorine groups also shield the polymer backbone, which contains CC bonds, from external radiation. For this reason, fluoropolymers are suitable for continuous operating temperatures of approximately 260°C. This is significantly higher than the temperatures of around 150°C that can occur in radiation-emitting optoelectronic components, such as LEDs. Furthermore, fluoropolymers are resistant to a wide range of chemicals and exhibit low flammability. They also possess very high transparency and transmittance, even to short-wave radiation such as UV radiation.

[0015] The high thermal stability of fluoropolymers can be demonstrated experimentally by the fact that they often exhibit minimal mass loss, frequently less than one percent by weight, even at very high temperatures of up to 488°C. Furthermore, their properties remain largely constant over a wide temperature range, from -260°C to +260°C, and in some phases up to +300°C.

[0016] Fluoropolymers exhibit high stability across a broad spectral range with respect to short-wave electromagnetic radiation. For example, they are also stable against UV radiation and can even withstand continuous exposure to high-energy UV radiation. Surprisingly, this high long-term stability with respect to short-wave radiation is also present in fluoropolymers that exhibit high transmission of high-energy radiation (e.g., ultraviolet radiation with wavelengths in the range of 410 to 230 nm). In such fluoropolymers with high transmittance for short-wave radiation, the radiation is not reflected or absorbed by the outer layers of the polymer material.

[0017] Surprisingly, even at high temperatures (sometimes well above 150°C) and in the presence of short-wave radiation such as UV radiation, radiolucent fluoropolymers are exceptionally well-suited for use as radiolucent components in radiation-emitting optoelectronic devices due to their stability and, in particular, their consistent radiolucency. They remain stable and radiolucent even in the area of ​​highest radiation exposure, the main radiation emission surface, over extended periods of operation.

[0018] Furthermore, significantly higher requirements are placed on the radiation transmittance of radioactive elements (for a broad radiation range, e.g., also for UV radiation) over a long operating period than on other components of the radiation-emitting device, e.g., housing components that are not located in the area of ​​the main radiation emission surface. Fluoropolymers can, however, also be used for such applications.

[0019] In contrast to conventional optoelectronic devices, the radiation-emitting optoelectronic devices according to the invention are characterized by a longer lifespan, a lower tendency to yellowing and thus lower losses in brightness.

[0020] The following section discusses various embodiments of the present invention: In one embodiment of the radiation-emitting optoelectronic device according to the invention, the radiation-transmitting element consists of the fluoropolymer.

[0021] In one different embodiment of the radiation-emitting optoelectronic device according to the invention, the radiation-transmitting element comprises the fluoropolymer and at least one additive. The additive can, for example, be a dye. In particular, the additive can be a wavelength converter that can convert at least part of the radiation emitted by the radiation-emitting optoelectronic semiconductor into longer-wavelength, i.e., lower-energy, radiation.

[0022] In a particularly preferred embodiment of the radiation-emitting optoelectronic device according to the invention, the radiation-transmitting element is a potting material. In this case, the potting material comprises the fluoropolymer or can consist of the fluoropolymer.

[0023] The stability requirements, particularly the requirements for consistently good transmission across a broad radiation spectrum, including UV radiation, are especially high for potting materials, as the potting material and the radiation-emitting optoelectronic semiconductor can be in direct contact. The potting material experiences an additional temperature increase in this situation (e.g., due to a Stokes shift). In particular, heat dissipation via the potting compound and the housing is very slow, which can lead to elevated temperatures within the potting compound.

[0024] Furthermore, because the radiation-transmitting element is a potting material, it is possible to manufacture the radiation-emitting components according to the invention with minimal effort and therefore cost-effectively.

[0025] In a further development of the invention, the radiation-transmitting element is spaced apart from the radiation-emitting semiconductor (also frequently referred to as a "remote application"). For example, a cavity can exist between the radiation-transmitting element and the radiation-emitting semiconductor. In this way, the thermal stress can be reduced, for example, by avoiding direct contact with the semiconductor.

[0026] In a particularly preferred embodiment of the radiation-emitting optoelectronic device according to the invention, the radiation-emitting semiconductor emits at least partially ultraviolet radiation. Ultraviolet radiation-emitting optoelectronic devices, such as UV LEDs, are used for a wide variety of applications. They are used, for example, for sterilization purposes, such as for sterilizing surfaces or water. Another area of ​​application is dentistry, such as the curing of dental fillings. UV radiation-emitting optoelectronic devices are also used in optical sensors. Numerous analytical techniques in the fields of forensics, as well as human and veterinary medicine, for example, for the examination of body fluids, such as for protein analysis, rely on UV radiation-emitting devices. In addition, there are devices used for light therapy.Furthermore, UV-emitting devices play an important role in a number of printing techniques. In addition, a number of phosphor-based radiation-emitting devices can be operated particularly efficiently with UV LED pumps.

[0027] The stability requirements are particularly high with regard to high-energy UV radiation. Furthermore, the radiation-transmitting element must exhibit high transmission against UV radiation throughout its entire operating period, even when exposed to short-wave UV radiation with wavelengths below 410 nm.

[0028] The inventors recognized that fluoropolymers containing radiolucent elements meet these high requirements. Conventional polymers, on the other hand, are usually not sufficiently stable and generally not radiolucent in the UV range.

[0029] The transmission of UV radiation is significantly higher in fluoropolymers than in conventional polymers. Conventional polymers typically have an absorption edge at around 350-400 nm, meaning that no significant transmission occurs at wavelengths below 350 nm. In contrast to conventional polymers, fluoropolymers, such as those used in the present invention, often exhibit a transmission of more than 90%, and frequently greater than or equal to 94%, even at wavelengths in the range of 250 nm to 300 nm.

[0030] In another embodiment of the radiation-emitting optoelectronic device according to the invention, the radiation-emitting semiconductor emits at least partially UV radiation in the range of 400-320 nm (near-UV light, abbreviated UVA). Furthermore, the radiation-emitting semiconductor can also emit at least partially UV radiation in the range of 320-290 nm (mid-UV, abbreviated UVB) or even UV radiation in the range of 290-100 nm (far-UV, abbreviated UVC).

[0031] Fluoropolymers containing radiation-permeable elements are more stable against the aforementioned types of UV radiation and often even against shorter-wavelength UV radiation (e.g., vacuum UV or even extreme UV) than conventional polymers and are usually also more radiation-permeable than conventional polymers.

[0032] The radiation-emitting optoelectronic device according to the invention has a housing body which also comprises at least one fluoropolymer, wherein the housing body is in contact with the radiation-transmitting element.

[0033] By using a fluoropolymer for both the housing and the radiolucent element, the stability of the radiation-emitting optoelectronic devices can be further increased. For example, high temperatures and high-energy radiation can lead to preferential degradation at the contact points between the radiolucent element and the housing in some radiation-emitting optoelectronic devices, making these points a weak point in the overall assembly. Manufacturing both components—the housing and the radiolucent element—from fluoropolymers with similar chemical properties allows for a particularly strong bond between the components, which can positively impact their overall service life. This could also potentially prevent yellowing at the contact points.

[0034] In another embodiment, the housing body consists of a fluoropolymer.

[0035] The housing body and the radiation-transmitting element contain the same fluoropolymer.

[0036] Furthermore, it is possible for both the housing body and the radiation-transmitting element to contain or be made of the same fluoropolymer. Using the same fluoropolymer allows for a particularly stable bond between the two components.

[0037] Alternatively, the radiation-emitting element can be made of or consist of a fluoropolymer, while the housing uses a fluoropolymer only as a matrix material, into which other materials, such as radiation-reflecting particles of inorganic oxides like TiO2, can be incorporated. In this way, the housing material can be colored white and thus highly reflective. For example, the housing can also contain porous fluoropolymers that exhibit particularly high reflectivity, e.g., greater than 90% or 95%. Thus, a radiolucent fluoropolymer for the radiation-emitting element can be combined with a reflective fluoropolymer for the housing.

[0038] In the radiation-emitting optoelectronic device according to the invention, the fluoropolymer has a first recurring structural unit A of the following general formula: wherein the substituents X1 to X4 are each independently selected from the group comprising: - Hydrogen, - Halogens, especially chlorine and fluorine, - R - OR where the remainder R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be and wherein at least one of the substituents X1 to X4 is fluorine.

[0039] Here and in the following, the symbol “*” represents binding sites of the repeating structural unit that are connected to the next repeating structural unit. Furthermore, end groups can terminate the polymer chain; these may, for example, be selected from the same group of substituents as substituents X1 to X4. However, other common end groups are also conceivable.

[0040] The inventors of the present invention have recognized that polymers with the aforementioned recurring structural unit A are particularly well suited for the radiation-emitting optoelectronic devices according to the invention. It is particularly preferred if at least two of the residues X1-X4 are fluorine atoms. It is even more preferred if at least three or exactly three of the residues X1-X4 are fluorine atoms. In another particularly preferred embodiment, four of the residues are fluorine atoms. Overall, the stability increases with an increasing number of fluorine atoms.

[0041] R can be a hydrocarbon residue C1-C 10R, preferably being a hydrocarbon residue C1-C5, particularly C1-C3. The hydrocarbon residue can be, for example, saturated, unsaturated, normal, branched, or cyclic hydrocarbon residues, especially alkyl residues. Aromatic residues are also conceivable. R can be unsubstituted or substituted.

[0042] It is particularly preferred if R is a fluorinated hydrocarbon residue C1-C 10 is, for example, a fluorinated hydrocarbon residue with up to five (C1-C5) or, more preferably, with up to three carbon atoms (C1-C3). R can, for example, have the general formula -C n F 2n+1exhibiting (with n less than or equal to 10, preferably n less than or equal to 5, or with n less than or equal to 3). For example, the R group can be a CF3 group, a C2F5 group, or a C3F7 group. However, incompletely fluorinated groups or longer chains are also conceivable. Generally, the higher the degree of fluorination, the more stable the fluoropolymer.

[0043] It is generally particularly advantageous if R is a perfluorinated hydrocarbon residue. The introduction of a residue R or OR for at least one or exactly one of the substituents X1 to X4 leads to improved processability of the fluoropolymer, in particular, it makes the fluoropolymer more castable. This opens up processing options via a variety of thermoplastic processes and is, for example, crucial for the use of fluoropolymers as components of potting compounds. Processing by casting, injection molding, film or tube extrusion are just a few examples of possible processing techniques. Such fluoropolymers thus offer advantages in processing compared to conventional fluoropolymers and, in particular, enable large-scale production.

[0044] In a preferred embodiment, A is a recurring structural unit selected from the group of recurring structural units of the following general formulas:

[0045] In a particularly preferred embodiment, the fluoropolymer is a fluoropolymer suitable for injection molding. Meltable fluorine-containing thermoplastics are especially preferred as fluoropolymers. These polymers are easily processed by injection molding or extrusion.

[0046] In another embodiment, the fluoropolymer is injection-moldable modified polytetrafluoroethylene (PTFE). (Conventional PTFE is not suitable for injection molding. Although PTFE transitions to a thermoplastic state when heated, it is not sufficiently fluid after the crystalline regions melt and therefore cannot be thermoplastically processed.) An example of a thermoplastic, injection-moldable fluoropolymer based on modified PTFE is the fluoropolymer with the brand name Moldflon® from ElringKlinger.

[0047] The fluoropolymer is a copolymer that, in addition to the first structural unit A, comprises at least one further structural unit B of the general formula that differs from the first structural unit A. where the substituents Y1 to Y4 are each independently selected from the group comprising: - Hydrogen, - Halogens, especially chlorine and fluorine, - R, - OR, where the residue R is a hydrocarbon residue or a fluorinated hydrocarbon residue C1-C 10 can be or where the structural unit B can have the formula.

[0048] The inventors of the present invention have found that copolymers of the described form, with two different recurring structural units A and B, are particularly well suited for radiation-transmitting elements in radiation-emitting optoelectronic devices according to the invention. The use of copolymers of the described form makes fluoropolymers accessible that are particularly well suited for potting. The diversity of the structural units A and B allows the properties of the copolymer to be flexibly adapted, for example, to optimize castability or to adjust other properties of the polymer (e.g., flexibility, chemical resistance, temperature resistance, fire resistance, mechanical strength, low-temperature processability, optical properties).

[0049] Optoelectronic devices of the described type can be manufactured with minimal effort and are therefore cost-effective. At the same time, they are characterized by high transmission across a broad radiation spectrum, including the UV range, which is maintained even during continuous operation despite radiation exposure and high temperatures.

[0050] In particular, if at least one or exactly one of the four substituents Y1 to Y4 is a group R or a group OR, the castability of the polymer is considerably improved.

[0051] In principle, the same substituents are conceivable for R as already described for structural unit A. The effects listed in connection with structural unit A for certain substituents R also apply to structural unit B. It is particularly preferred if R is a fluorinated or even perfluorinated hydrocarbon substituent, e.g., with the general formula -C n F 2n+1 is (with n less than or equal to 10, preferably n less than or equal to 5, or with n less than or equal to 3). For example, R can be -CF3, -C2F5 or -C3F7.

[0052] In a further embodiment of the radiation-emitting optoelectronic device according to the invention, the fluoropolymer is a copolymer with a first structural unit A and a second structural unit B, wherein the structural unit A is selected from the group comprising: and wherein the structural unit B is selected from the group comprising: where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be.

[0053] R can in turn comprise the residues already described above.

[0054] Copolymers of the described form are not only UV-stable, thermally stable, chemically resistant and sustainably permeable to UV radiation, but they are also characterized by their good castability and processability, thus allowing the production of particularly easy-to-manufacture and cost-effective radiation-emitting optoelectronic devices.

[0055] A particularly preferred embodiment is one in which the radiolucent element comprises a copolymer whose structural unit A includes a unit of the formula. Copolymers with this structural unit A are particularly stable and radiolucent.

[0056] In one embodiment, the polymer is a block copolymer.

[0057] In a further embodiment of the invention, the fluoropolymer is a copolymer that is a statistical copolymer. That is, the structural units A and B are statistically distributed.

[0058] In one embodiment of the invention, the copolymer is a periodic copolymer in which the structural units A and B are present in a recurring regular order (e.g., ... -AAAA-B-AAAA-B-AAAA-... etc.).

[0059] In a further and particularly preferred embodiment, the copolymer has an alternating sequence of structural units A and B (i.e., ...-ABABAB-...).

[0060] Alternating copolymers, in particular, are characterized by a particularly good combination of good UV radiation permeability, resistance and processability.

[0061] In a further embodiment of the invention, the fluoropolymer has yet another structural unit C, which is different from structural units A and B and can be described with the same general formula as structural unit B.

[0062] A preferred embodiment of the present invention utilizes a fluoropolymer as a radiation-transmitting element, comprising a radiation-transmitting element, which is a - Ethylene chlorotrifluoroethylene copolymer (ECTFE), - Ethylene tetrafluoroethylene copolymer (ETFE), - Perfluoroalkoxy polymers (PFA), - Fluorinated ethylene propylene copolymer (FEP), - Polyvinyl fluoride (PVF), - Polychlorotrifluoroethylene (PCTFE), - Copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV), - Copolymer of tetrafluoroethylene and 2,2 bis(trifluoromethyl)-4,5-difluoro-1,3-dioxolane (PTFE-AF).

[0063] The radiation-transmitting element may also contain mixtures of the aforementioned polymers or consist of one or more of them. Furthermore, it is possible that the radiation-transmitting element contains modified forms of the aforementioned polymers.

[0064] Particularly suitable as a radiation-transmitting element for radiation-emitting optoelectronic devices according to the present invention are radiation-transmitting elements comprising the polymer ECTFE. ECTFE is a fluoropolymer obtained by copolymerization of chlorotrifluoroethylene and ethylene. It thus has as a structural unit A

[0065] It is characterized as structural unit B.

[0066] The structural units can, for example, be arranged in an alternating sequence.

[0067] Particularly suitable as a radiation-transmitting element for radiation-emitting optoelectronic devices according to the present invention are also radiation-transmitting elements comprising the polymer ETFE, which is a copolymer of tetrafluoroethylene and ethylene. The polymer has as structural unit A:

[0068] ETFEaut. As structural unit B, it features

[0069] ETFE has a particularly high UV radiation transmittance and also possesses high temperature resistance, good chemical resistance and high mechanical strength.

[0070] Radiation-emitting optoelectronic devices are also preferred, wherein the radiation-transparent element comprises PFA or similar polymers. It is particularly preferred if the structural unit A comprises and the structural unit B comprises.

[0071] R is defined as already described for the general formula of the structural units A and B.

[0072] PFA has good chemical resistance, thermal resistance and exhibits high fire resistance.

[0073] For example, a suitable polymer can be obtained by copolymerization of tetrafluoroethylene and perfluorovinyl propyl ether. PFA-based polymers have a fluorinated alkoxy substituent, which increases the polymer's deformability. The oxygen functionality also improves the material's transparency, for example, its permeability to UV radiation, as is desirable for potting compounds of the present invention.

[0074] PFA-based fluoropolymers with particularly good processability include, for example, the fluoropolymers marketed by Solvay under the brand name "Hyflon® PFA". Many other fluoropolymers marketed under the brand name "Hyflon®" (e.g., "Hyflon® MFA") exhibit comparable properties. Instead of introducing an alkoxy substituent, it is also possible to increase the deformability and thus the castability of corresponding polymers by introducing an alkyl, and in particular a fluorinated alkyl, substituent. This is done, for example, in FEP, which is a copolymer of tetrafluoroethylene and a different monomer unit based on an at least partially fluorinated olefin (e.g., hexafluoropropylene). FEP polymers possess the following structural unit A:

[0075] The structural unit B is:

[0076] R is defined as already described for the general formula of the structural units A and B.

[0077] FEP polymers possess particularly good UV radiation transmission, chemical and thermal resistance, and high fire resistance. They also enable exceptionally smooth surfaces.

[0078] Polyvinyl fluoride (PVF), which has a recurring structural unit A, is also suitable as a fluoropolymer in a radiation-emitting device according to the invention.

[0079] Polychlorotrifluoroethylene (PCTFE), which has A as a recurring structural unit, is also suitable as a fluoropolymer.

[0080] The polymer THV is particularly suitable as a fluoropolymer in radiation-emitting optoelectronic devices. THV stands for the copolymer formed by the copolymerization of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride. It features the structural unit A, the structural unit Bund, and a third, different, recurring structural unit Cauf.

[0081] THV is therefore a copolymer comprising three different repeating structural units. It possesses particularly advantageous optical properties, high flexibility, and is very easy to process even at low temperatures. In particular, the good processability of THV even at low temperatures represents a significant advantage over many conventional fluoropolymers when used in the radiation-emitting optoelectronic devices according to the invention.

[0082] The polymer PTFE-AF, a copolymer of tetrafluoroethylene and 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxolane, is particularly suitable as a fluoropolymer in radiation-emitting optoelectronic devices according to the invention. PTFE-AF features the recurring structural unit A.

[0083] PTFE-AF also exhibits another recurring structural unit B.

[0084] PTFE-AF also exhibits particularly good UV radiation transmission and processability.

[0085] The listed polymers are examples of particularly suitable fluoropolymers, each of which is a fluorine-containing thermoplastic. Meltable fluorine-containing thermoplastics can be manufactured by injection molding and extrusion and are therefore particularly well-suited for large-scale industrial processes. The fluoropolymers mentioned are common, commercially available polymers and are thus readily obtainable. Modified forms of the listed polymers can also be used in the present invention. As will be shown using PFA as an example, there are often numerous modifications of the respective polymers. For example, commercially available modifications of PFA include "PFA N" with improved adhesion properties, "PFA FLEX" with increased deformability, and "PFA UHP" with particularly high purity.PFA FLEX and PFA UHP also exhibit improved transmission and reduced susceptibility to cracking (i.e., a lower tendency to form unwanted cracks or fissures) and are therefore particularly suitable for radiolucent elements. Radiolucent elements comprising these polymers also generally show a significantly lower tendency to yellow than conventional polymers.

[0086] However, the invention is not limited to the fluoropolymers mentioned above.

[0087] In a further embodiment, the mean molecular mass of the fluoropolymers of the radiolucent element of the radiation-emitting optoelectronic device according to the invention can be in the range of 1000 g / mol to 10000000 g / mol, in particular between 1000 g / mol and 1000000 g / mol, more preferably between 2000 g / mol and 800000 g / mol and most preferably between 4000 g / mol and 500000 g / mol.

[0088] Another preferred embodiment of the radiation-emitting optoelectronic device according to the invention is designed as a light-emitting diode (LED) that emits UV light. It is therefore a UV LED.

[0089] For example, the LED could be a thin-film light-emitting diode chip. A thin-film light-emitting diode chip is characterized in particular by the following features: - a reflective layer is applied or formed on a first main surface of the housing body of a radiation-generating epitaxial layer sequence facing a support element, which reflects at least part of the electromagnetic radiation generated in the epitaxial layer sequence back into it; - the epitaxial layer sequence has a thickness in the range of 20 µm or less, particularly in the range of 10 µm; and - the epitaxial layer sequence contains at least one semiconductor layer - i.e., a radiation-emitting optoelectronic semiconductor - with at least one surface that has a mixing structure which ideally leads to an approximately ergodic distribution of light in the epitaxial layer sequence, i.e., it exhibits a scattering behavior that is as ergodic and stochastic as possible.

[0090] A basic principle of a thin-film light-emitting diode chip is described, for example, in SCHNITZER, I., et al. 30% external quantum efficiency from surface textured, thin-film light-emitting diodes. Applied Physics Letters, 1993, Vol. 63, No. 16, pp. 2174-2176.

[0091] The invention further relates to a method for manufacturing a radiation-emitting optoelectronic device, wherein the radiation-transparent element is a potting material (3), comprising the steps: Step A: Place a housing body (1) and the radiation-emitting semiconductor (2). Step B: Potting the semiconductor (2) with the potting material (3).

[0092] By using a castable potting compound, the manufacturing process can be designed without significant technical effort and is therefore cost-effective. A direct connection between the components of the housing body, which at least partially surrounds the radiation-emitting semiconductor, and the potting compound is easily achieved through potting. It is also possible to completely enclose the semiconductor with the potting compound, ensuring direct contact between the two. The process is time-saving and suitable for large-scale production.

[0093] Further details, features and advantages of the subject matter of the invention will become apparent from the following description of the figures and embodiments.

[0094] The figures show: Fig. 1 the simplified, schematic side view of a radiation-emitting optoelectronic device according to the invention, wherein the radiation-transparent element (3) is a potting material. Fig. 2 the simplified, schematic side view of a radiation-emitting optoelectronic device according to the invention, wherein the radiation-transparent element (3) is spaced apart from the radiation-emitting semiconductor (2). Fig. 3 Measurements of the transmission of electromagnetic radiation from infrared radiation to UV radiation for an ETFE fluoropolymer (brand name: Fluon), glass, and the polymer polycarbonate.

[0095] The following section describes in more detail the respective figures or embodiments for illustrative purposes.

[0096] Fig. Figure 1 shows a simplified schematic representation of a radiation-emitting optoelectronic device according to an embodiment of the present invention, comprising a housing body (1), at least one optoelectronic radiation-emitting semiconductor (2), and a radiation-transparent element (3) distinct from the housing body (1), wherein the housing body (1) surrounds the at least one optoelectronic radiation-emitting semiconductor (2) at least partially. The radiation-transparent element (3) is arranged in the beam path of the radiation-emitting semiconductor (2). It may be located, in particular, in the region of the main radiation emission surface. The radiation-transparent element is a potting material comprising a fluoropolymer. It may be in direct contact with both the housing body (1) and, in particular, with the radiation-emitting semiconductor (2).The device may also contain other typical elements for radiation-emitting optoelectronic devices, such as appropriate substrates, conductor tracks, thermal interface materials, as well as reflective layers and other common components, such as those found in corresponding radiation-emitting optoelectronic devices like LEDs.

[0097] Fig. Figure 2 also shows a simplified schematic representation of a radiation-emitting optoelectronic device according to another embodiment of the present invention, comprising a housing body (1), at least one optoelectronic radiation-emitting semiconductor (2), and a radiation-transparent element (3) distinct from the housing body (1), wherein the housing body (1) surrounds the at least one optoelectronic radiation-emitting semiconductor (2) at least partially. The radiation-transparent element (3) is arranged in the beam path of the radiation-emitting semiconductor (2). It may be located, in particular, in the region of the main radiation emission surface. The radiation-transparent element (3) of the embodiment shown is spaced apart from the radiation-emitting semiconductor (2). For example, a cavity may be located between the radiation-transparent element (3) and the radiation-emitting semiconductor (2).The radiation-transparent element could, for example, be a plate, such as a wavelength conversion plate.

[0098] Fig.Figure 3 shows measurements on three different materials, where the transmission (T), i.e., the permeability of electromagnetic radiation, is given as a percentage (%) as a function of the wavelength (λ) of the emitted radiation in nanometers (nm). The measurements demonstrate that conventional materials exhibit only limited transmission, particularly for short wavelengths in the UV range. Therefore, due to their insufficient UV transmission, they are unsuitable for use in UV-emitting optoelectronic devices. Polycarbonates, in particular, which contain radiolucent elements, are unsuitable for transmitting UV radiation. The UV transmission of glass substrates is slightly better than that of polycarbonate, but even here, transmission is already considerably limited for wavelengths slightly below 400 nm, for example, at 350 nm.In contrast, the fluoropolymer, which is an ETFE polymer (brand name Fluon), is far more permeable to radiation in the UV range.

Claims

[1] Radiation-emitting optoelectronic device - comprehensive - a housing body (1), - at least one optoelectronic radiation-emitting semiconductor (2), - a radiation-transparent element (3) different from the housing body (1), - wherein the housing body (1) surrounds at least one optoelectronic radiation-emitting semiconductor (2) at least partially, - wherein the radiation-transparent element (3) is arranged in the beam path of the radiation-emitting semiconductor (2), and - wherein the radiolucent element (3) comprises a fluoropolymer and - wherein the housing body (1) also comprises a fluoropolymer and is in contact with the radiolucent element (3), wherein the housing body (1) and the radiolucent element (3) comprise the same fluoropolymer, wherein the fluoropolymer is a copolymer, comprising a first structural unit A of the following general formula: wherein the substituents X1 to X4 are each independently selected from the group comprising: - Hydrogen, - Halogens, especially F and Cl, - R, - OR, where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be and, where at least one of the substituents X1 to X4 is fluorine, and at least one further second structural unit B, different from structural unit A, of the following general formula: wherein the substituents Y1 to Y4 are each selected independently of one another from the group comprising: - Hydrogen, - Halogens, especially F and Cl, - R - OR where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be or where the structural unit B has the formula. [2] Radiation-emitting optoelectronic device according to the previous claim, wherein the radiation-transparent element (3) is a potting material. [3] Radiation-emitting optoelectronic device according to one of the preceding claims, wherein the radiation-transparent element (3) is spaced apart from the radiation-emitting semiconductor (2). [4] Radiation-emitting optoelectronic device according to one of the preceding claims, wherein the radiation-emitting semiconductor (2) emits UV radiation. [5] Radiation-emitting optoelectronic device according to any one of the preceding claims, wherein the fluoropolymer of the radiolucent element (3) is a copolymer with a first structural unit A and a second structural unit B, wherein the structural unit A is selected from the group comprising: and wherein the structural unit B is selected from the group comprising: where R is a hydrocarbon residue C1-C 10 or a fluorinated hydrocarbon residue C1-C 10 may be. [6] Radiation-emitting optoelectronic device according to one of the preceding claims, wherein the copolymer has an alternating sequence of structural units A and B. [7] Radiation-emitting optoelectronic device according to any one of the preceding claims, wherein the fluoropolymer of the radiolucent element (3) is a polymer selected from the following group: - Ethylene chlorotrifluoroethylene copolymer (ECTFE), - Ethylene tetrafluoroethylene copolymer (ETFE), - Fluorinated ethylene propylene copolymer (FEP) - Copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV), - Copolymer of tetrafluoroethylene and 2,2 bis(trifluoromethyl)-4,5-difluoro-1,3-dioxolane (PTFE-AF) . [8] Method for manufacturing a radiation-emitting optoelectronic device according to claim 2, comprising the steps A) Providing a housing body (1) and the radiation-emitting semiconductor (2), B) Potting the semiconductor (2) with the potting material (3).

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