Optoelectronic semiconductor component and scattering agent

Abstract

Optoelectronic semiconductor component (1) with - at least one optoelectronic semiconductor chip (2) for generating electromagnetic radiation, and - a conversion element (3) which is designed to convert at least part of the radiation emitted by the semiconductor chip (2) into radiation of a different wavelength, where - the conversion element (3) comprises at least one phosphor and scattering particles (33), - the conversion element (3) comprises at least one matrix material (34) in which at least the scattering particles (33) are embedded, - a refractive index difference between the matrix material (34) and a material of the scattering particles (33) at a temperature of 300 K is at most 0.06 and at 400 K at least 0.075, and - the refractive index difference is greater at a temperature of 380 K than at 300 K, - wherein the phosphor is in the form of particles and is embedded in the matrix material (34) together with the scattering particles (33), - wherein the phosphor and the scattering particles (33) are mixed, the scattering particles having an average diameter of at least 400 nm and at most 10 µm, - wherein the weight proportion of the scattering particles (33) in the conversion element (3) is between 0.5% and 50%, - wherein the weight fraction of the phosphor is between 5% and 20% inclusive and the particles of the phosphor have an average diameter of between 5 µm and 40 µm inclusive, which is larger than the average diameter of the scattering particles (33).

Description

[0001] An optoelectronic semiconductor component is specified. Furthermore, a scattering agent for a conversion element for an optoelectronic semiconductor component is specified.

[0002] The document DE 102010034913 A1 describes a radiation-emitting component.

[0003] The document DE 102005044396 A1 describes an optical semiconductor device.

[0004] The document DE 102005061828 A1 describes a wavelength-converting converter material and a light-emitting optical component.

[0005] The document DE 102007059548 A1 describes an optoelectronic component.

[0006] The publications US 2011 / 0018026 A1 and US 2011 / 0248304 A1 describe light-emitting devices.

[0007] The document DE 19638667 A1 describes a semiconductor component that emits mixed-colored light.

[0008] One problem to be solved is to provide an optoelectronic semiconductor component and a scattering agent therefor, with which a comparatively constant color emission can be realized despite temperature changes.

[0009] According to at least one embodiment of the optoelectronic semiconductor component, it comprises at least one optoelectronic semiconductor chip. The optoelectronic semiconductor chip is provided for generating electromagnetic radiation. In particular, the optoelectronic semiconductor chip comprises a semiconductor layer sequence.

[0010] The semiconductor layer sequence is preferably based on a III-V compound semiconductor material. The semiconductor material is, for example, a nitride compound semiconductor material such as Al n In 1-n-m Ga m N or a phosphide compound semiconductor material such as Al n In 1-n-m Ga mP or an arsenide compound semiconductor material such as Al n In 1-n-m Ga m As, where 0 ≤ n ≤ 1, 0 ≤ m ≤ 1, and n + m ≤ 1, respectively. The semiconductor layer sequence can contain dopants as well as additional components. For the sake of simplicity, however, only the essential components of the crystal lattice of the semiconductor layer sequence, i.e., Al, As, Ga, In, N, or P, are specified, even though these may be partially replaced and / or supplemented by small amounts of other substances. The semiconductor layer sequence is preferably based on AlInGaN.

[0011] The semiconductor layer sequence comprises at least one active layer configured to generate electromagnetic radiation. The active layer includes, in particular, at least one pn junction and / or at least one quantum well structure. Radiation generated by the active layer during operation lies, in particular, in the spectral range between 400 nm and 800 nm.

[0012] According to at least one embodiment of the semiconductor component, it includes a conversion element. The conversion element is configured to convert at least a portion of the radiation emitted by the semiconductor chip during operation into radiation of a different wavelength. For example, the semiconductor chip emits blue light, and the conversion element converts a portion of this blue light into green and / or green-yellow and / or green-orange and / or red light. Particularly preferably, the semiconductor component emits mixed radiation composed of the radiation emitted by the conversion element and the radiation directly generated by the semiconductor chip. The mixed radiation is, for example, white light.

[0013] According to at least one embodiment of the semiconductor component, the conversion element contains one or more phosphors. The phosphors are based, for example, on a rare-earth-doped garnet such as YAG:Ce, a rare-earth-doped orthosilicate such as (Ba,Sr)2SiO4:Eu, or a rare-earth-doped silicon oxynitride or silicon nitride such as (Ba,Sr)2Si5N8:Eu. Several different phosphors can be present in the conversion element, either intermixed or spatially separated from one another.

[0014] According to at least one embodiment of the semiconductor component, the conversion element comprises scattering particles. The scattering particles are configured to scatter the radiation converted by the conversion element and / or the radiation generated directly by the semiconductor chip due to a refractive index difference from an environment and / or due to reflective properties and / or due to light diffraction. The scattering particles preferably absorb no or substantially no radiation generated by the semiconductor chip or radiation converted by the conversion element. Furthermore, a material of the scattering particles can be permeable to the radiation generated by the semiconductor chip or converted by the conversion element.

[0015] According to at least one embodiment, the conversion element comprises at least one matrix material. The matrix material is, for example, a silicone, a silicone-epoxy hybrid material, or an epoxy. The matrix material is preferably clear and transparent to the radiation generated by the semiconductor chip and converted by the conversion element. The scattering particles are at least partially embedded in the matrix material. This means that all or some of the scattering particles are arranged in direct contact with the matrix material at certain locations. In particular, the scattering particles are mixed into the matrix material in a homogeneously distributed manner.

[0016] According to at least one embodiment of the semiconductor component, a refractive index difference between the matrix material and the material of the scattering particles at a temperature of 300 K is at most 0.15. It is possible for the refractive index difference to be at most 0.10, or at most 0.07, or at most 0.05, or at most 0.03. In other words, the refractive indices of the matrix material and the material of the scattering particles differ little or not at all at room temperature.

[0017] The refractive index difference between the matrix material and the scattering particle material is greater at a temperature of 380 K than at 300 K. Alternatively or additionally, the refractive index difference between the matrix material and the scattering particle material may be greater at a temperature of 400 K and / or at a temperature of 420 K than at 300 K. In other words, the refractive index difference increases from room temperature to a steady-state operating temperature of the semiconductor chip. Due to an increase in the refractive index difference, the scattering particles exhibit a greater scattering effect at elevated temperatures than at room temperature.

[0018] The optoelectronic semiconductor component comprises one or more optoelectronic semiconductor chips for generating electromagnetic radiation. The semiconductor component includes a conversion element configured to convert at least a portion of the radiation emitted by the semiconductor chip into radiation of a different wavelength. The conversion element comprises at least one phosphor and scattering particles, as well as at least one matrix material. The scattering particles are partially or completely embedded in the matrix material. A refractive index difference between the matrix material and a material of the scattering particles is at most 0.15 at a temperature of 300 K. The refractive index difference between the matrix material and the material of the scattering particles is greater at a temperature of 380 K than at a temperature of 300 K.

[0019] The conversion element is therefore deliberately added a material in the form of scattering particles whose refractive index at room temperature is close to the refractive index of the matrix material. Furthermore, the scattering particles are sized to achieve a light-scattering effect. Heating reduces the refractive index of the matrix material, which is typically silicone. If the refractive indices of the matrix material and the material of the scattering particles are close to each other at room temperature, this reduction in the refractive index of the matrix material leads to a significant change in the scattering effect of the scattering particles as the temperature increases.

[0020] An increased scattering effect changes the average path of radiation directly generated by the semiconductor chip in the conversion element. This also increases the degree of conversion, meaning that more of the radiation generated by the semiconductor chip is converted into other radiation by the conversion element. This reduces the blue component of the radiation, and the color coordinate of the mixed radiation shifts away from blue. This makes it possible to at least partially compensate for a change in the color coordinate caused by a change in the wavelength of the radiation directly emitted by the optoelectronic semiconductor chip when the temperature changes.

[0021] According to at least one embodiment of the semiconductor component, the scattering particles have an average diameter of at least 50 nm, or at least 250 nm, or at least 400 nm. Alternatively or additionally, the average diameter of the scattering particles is at most 20 µm, or at most 10 µm, or at most 5.5 µm, or at most 3 µm. In other words, the scattering particles have comparatively large diameters. In particular, the scattering particles, based on an average diameter, are significantly larger than those of thixotropic agents. The scattering particles can have a targeted distribution of average diameters.

[0022] According to at least one embodiment of the semiconductor component, the material of the scattering particles is silicon dioxide, glass, quartz, silicon nitride, or a metal fluoride such as barium fluoride, calcium fluoride, or magnesium fluoride. It is possible for the scattering particles to be formed from several of the aforementioned materials, or for scattering particles made of different materials to be used in combination.

[0023] According to at least one embodiment of the semiconductor component, the matrix material is a silicone or a silicone-epoxy hybrid material, wherein the refractive index of the matrix material at room temperature is at least 1.38 or at least 1.40, and alternatively or additionally at most 1.54 or at most 1.50 or at most 1.48. Room temperature refers to a temperature of 300 K. For example, the refractive index of the matrix material is 1.41 or 1.46, with a tolerance of at most 0.01.

[0024] According to at least one embodiment of the semiconductor component, at room temperature, the refractive index of the matrix material is less than or equal to the refractive index of the scattering particles. In particular, the matrix material exhibits a decrease in the refractive index with increasing temperature, and the material of the scattering particles exhibits an increase in the refractive index with increasing temperature, at least in a temperature range from 300 K to 400 K. It is also possible that the refractive index of the material of the scattering particles also decreases with increasing temperature, but then at a lower rate than the refractive index of the matrix material.

[0025] A refractive index change of the scattering particles is approximately 0.1 × 10 -5 K -1 up to 1 × 10 -5 K -1and is thus essentially negligible compared to the refractive index change of the matrix material, which is silicone. The refractive index change of silicone is approximately -4 × 10 -4 K -1 .

[0026] The weight fraction of the scattering particles, based on the matrix material or the entire conversion element, is at least 0.5% or at least 1%. In addition, the weight fraction is at most 50%, at most 20%, at most 12%, or at most 5%.

[0027] The phosphor is in the form of particles. The average diameter of the phosphor particles is then, for example, at least 2 µm, at least 3 µm, or at least 5 µm. Alternatively or additionally, the average diameter is at most 20 µm, at most 15 µm, or at most 40 µm.

[0028] The phosphor particles are embedded in the matrix material together with the scattering particles. The conversion element then preferably comprises exactly one matrix material. It is possible for the phosphor particles and the scattering particles to be intermixed, in particular homogeneously intermixed.

[0029] It is also possible for the phosphor particles to be partially sedimented and for the scattering particles to be homogeneously or substantially homogeneously distributed in the matrix material. The phosphor particles may also have an increased concentration on a side of the conversion element facing the semiconductor chip, while the scattering particles may be present on a side of the conversion element facing away from the semiconductor chip.

[0030] The weight fraction of the phosphor, based on the matrix material or the entire conversion element, is between 5% and 20% inclusive. However, the weight fraction can also be between 10% and 25% inclusive, between 5% and 80% inclusive, or between 60% and 80% inclusive.

[0031] According to at least one embodiment of the semiconductor component, the phosphor particles have a larger average diameter than the scattering particles. For example, the average diameters differ from one another by at least a factor of 2 or by at least a factor of 5. Furthermore, it is possible for the number of scattering particles to exceed the number of phosphor particles, for example by at least a factor of 2, by at least a factor of 5, or by at least a factor of 10.

[0032] According to at least one embodiment of the semiconductor component, the phosphor and the scattering particles are present in an unmixed state. For example, the phosphor or the phosphor particles are present in a first matrix material and the scattering particles are present in a second matrix material. It is also possible for the phosphor to be formed into a compact layer and for the matrix material with the scattering particles to be applied to this layer. A distance between the scattering particles and the phosphor is, for example, at most 250 µm, or at most 150 µm, or at most 50 µm. Preferably, the phosphor and the matrix material, with the scattering particles distributed therein, in particular homogeneously, are arranged directly adjacent.

[0033] According to at least one embodiment of the semiconductor component, the phosphor of the conversion element is formed by a single phosphor. The phosphor is then preferably formed from precisely one of the following materials: a green-emitting orthosilicate with the empirical formula (Ba x ,Sr y ,Ca 1-x-y ) 2-z Eu z SiO4 with 0.25 ≤ x < 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1; a green-emitting nitrido-orthosilicate with the molecular formula (Ba x , Sr y , Ca 1-x-y ) 2-z Eu z Si(O a ,N (0,67-0,67a) )4 with 0.25 ≤ x < 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1.

[0034] If reference is made to a nitrido-orthosilicate, it is possible that this alternatively or additionally has the molecular formula AE (2-1,5x-y) RE x Eu y SiO (4-1,5x) N xwith 0 < x 0.1 and 0 < y 0.2 and with AE = Mg, Ca, Sr and / or Ba and RE = Sr, Y and / or one or more elements from the group of lanthanides.

[0035] According to at least one embodiment of the semiconductor component, the conversion element comprises a first phosphor and a second phosphor. The first phosphor is designed to emit in the green and / or green-yellow spectral range. The second phosphor is preferably configured to emit at longer wavelengths than the first phosphor, preferably in the red spectral range or the red-orange spectral range. The two different phosphors can be homogeneously mixed or layered.

[0036] The first phosphor and the second phosphor are preferably present in one of the following material combinations: - green emitting orthosilicate with the formula (Ba x , Sr y , Cal-x-y ) 2-z Eu z SiO4 with 0.25 ≤ x ≤ 1, 0 ≤ y ≤ 0.75 and 0 ≤ z ≤ 0.5 as well as red-emitting nitride with the formula (Ca x ,Sr l-x ) 2-y Eu y AlSi(N z , O (1,5-1,5z) )3 with 0 ≤ x ≤ 1, 0 < y ≤ 0.4 and 0 < z ≤ 1, - green emitting orthosilicate with the formula (Ba x ,Sr y ,Ca 1-x-y ) 2-z Eu z SiO4 with 0.25 ≤ x ≤ 1, 0 ≤ y ≤ 0.75 and 0 ≤ z ≤ 0.5 as well as red-emitting nitride with the formula (Sr x ,Ba 1-x ) 2-y Eu y Si5N8 with 0 < x < 1 and 0 < y < 0.3, - green emitting nitrido-orthosilicate with the formula (Ba x , Sr y , Ca 1-x-y ) 2-z Eu z Si(O a , N (0,67-0,67a) )4 with 0.25 ≤ x ≤ 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1 as well as red-emitting nitride with the formula (Ca x, Sr 1-x ) 2-y Eu y AlSi(N z ,O (1,5-1,5z))3 with 0 ≤ x ≤ 1, 0 < y ≤ 0.4 and 0 < z ≤ 1, or - green emitting nitrido-orthosilicate with the formula (Ba x , Sr y , Ca 1-x-y ) 2-z Eu z Si(O a , N (0,67-0,67a) )4 with 0.25 ≤ × ≤ 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1 as well as red-emitting nitride with the formula (Sr x ,Ba 1-x ) 2-y Eu y Si5N8 with 0 < x < 1, 0 < y ≤ 0.3.

[0037] The refractive index difference between the matrix material and the scattering particle material is at most 0.06 or at most 0.05 at 300 K, and the refractive index difference is at least 0.075 or at least 0.065 at 400 K. Alternatively or additionally, the refractive index difference changes from 300 K to 400 K by at least 20% or at least 30%.

[0038] Furthermore, a scattering agent is specified. The scattering agent can be used in a conversion element, as specified in one or more embodiments of the semiconductor chips described above. Features of the scattering agent are therefore also disclosed for the optoelectronic semiconductor chip, and vice versa.

[0039] In at least one embodiment, the scattering means is configured for a conversion element, wherein the conversion element is designed to convert radiation emitted by a semiconductor chip into radiation of a different wavelength. The scattering means comprises a matrix material and scattering particles embedded in the matrix material. A refractive index difference between the matrix material and a material of the scattering particles is smaller at a temperature of 300 K than at a temperature of 380 K.

[0040] An optoelectronic semiconductor component and a scattering agent described herein are explained in more detail below with reference to the drawings using exemplary embodiments. Like reference numerals indicate like elements in the individual figures. However, they are not drawn to scale; rather, individual elements may be exaggerated for clarity.

[0041] They show: Fig. 1 to 6 are schematic representations of embodiments of scattering bodies described here and of optoelectronic semiconductor chips described here, Fig. 7 a schematic representation of color location shifts with temperature changes, and Fig. 8 a schematic representation of color location changes for different scattering particles.

[0042] In Fig. Figure 1 shows a sectional view of an embodiment of an optoelectronic semiconductor component 1. The semiconductor component 1 comprises an optoelectronic semiconductor chip 2, which is mounted in a recess in a housing 4. The semiconductor chip 2 is preferably a light-emitting diode (LED) that emits blue light.

[0043] Furthermore, the semiconductor component 1 includes a conversion element 3, which is arranged downstream of the semiconductor chip 2 along a radiation direction and, like the semiconductor chip 2, is located in the recess of the housing 4. The conversion element 3 is configured to absorb a portion of the radiation generated by the semiconductor chip 2 during operation and convert it into different, longer-wavelength radiation. At the same time, the conversion element 3 serves as a scattering agent. Optionally, the conversion element 3 is lens-shaped.

[0044] The conversion element 3 comprises one or more phosphors and scattering particles. The phosphor or phosphors and the scattering particles can be homogeneously distributed within the conversion element 3. At room temperature, the scattering particles and a matrix material in which the phosphor and the scattering particles are embedded have approximately the same refractive index. If the temperature of the semiconductor chip 2, and thus of the conversion element 3, increases when the semiconductor component 1 is switched on, a refractive index difference between the matrix material of the conversion element 3 and the scattering particles in the conversion element 3 increases.

[0045] It is possible for the scattering particles to have an average diameter between 2.5 µm and 8.5 µm and to be made of silicon dioxide. The matrix material has a refractive index between 1.36 and 1.48, for example, at 300 K. The weight fraction of the scattering particles in the conversion element 3 is, for example, between 0.5% and 15% or between 6% and 15%.

[0046] With a temperature increase, for example, from approximately 300 K to approximately 380 K, a dominant wavelength emitted directly by semiconductor chip 2 shifts, for example, by approximately 3 nm to 5 nm toward higher wavelengths. The dominant wavelength is, in particular, the wavelength resulting from the intersection of the spectral color line of the CIE chromaticity diagram with a straight line. This straight line, starting from the white point in the CIE chromaticity diagram, runs through the actual color coordinate of the radiation.

[0047] Since the maximum sensitivity of the blue color receptor in the human eye is approximately 450 nm, the color locus of the radiation emitted by the semiconductor chip 2 shifts towards blue, at least if a wavelength of maximum intensity of this radiation is below 450 nm at room temperature, as is preferably the case here. As a result, mixed radiation emitted by the semiconductor component 1, composed of the radiation generated directly by the semiconductor chip 2 and the radiation converted by the conversion element 3, can appear bluer. Alternatively or additionally, a color locus shift towards blue can also occur due to the conversion efficiency of the phosphors decreasing with increasing temperature. The color locus shift due to this effect can also be at least reduced by combining the two phosphors.

[0048] Due to the increase in the refractive index difference between the matrix material and the scattering particles towards higher temperatures, the path of the blue light generated in the semiconductor chip 2 in the conversion element 3 is increased, thereby increasing the conversion efficiency of the conversion element 3. In other words, more blue light is converted into, for example, green light and / or red light, and thus less blue light is emitted by the semiconductor component 1. As a result, a color locus shift after switching on the semiconductor component 1, caused by a change in the dominant wavelength of the radiation generated by the semiconductor chip 2 with an increase in temperature, can be avoided or significantly reduced during a warm-up phase of the semiconductor chip 2.

[0049] In Fig. 2 shows a further embodiment of the semiconductor component 1. The semiconductor chip 2 is mounted on a carrier 5. The carrier 5 is, for example, a circuit board or a printed circuit board. As in the other figures and as in the case of the housing 4 according to Fig. 1, electrical conductor tracks and / or bonding wires are not shown to simplify the illustration.

[0050] A phosphor plate 36 is attached to a light exit side of the semiconductor chip 2, which faces away from the carrier 5. The phosphor(s) is / are located in the phosphor plate 36. The phosphor plate 36 is, for example, a ceramic plate into which phosphor particles are embedded or sintered. In a direction away from the carrier 5 and in a lateral direction around the semiconductor chip and the phosphor plate 36 is the matrix material 34 with the scattering particles 33 embedded therein. The phosphor plate 36 is thus located between the semiconductor chip 2 and the matrix material 34 with the scattering particles 33. The matrix material 34 with the scattering particles 33 is shaped like a hood and, together with the phosphor plate 36, forms the conversion element 3.

[0051] The scattering particles 33 have, for example, an average diameter between 400 nm and 1.5 µm and are made of silicon dioxide. The refractive index of the matrix material at 300 K is, in particular, between 1.39 and 1.48. The weight fraction of the scattering particles 33, based on the matrix material 34, is, for example, between 0.75% and 6% or between 5% and 60%.

[0052] In the embodiment according to Fig. 3, both the phosphor plate 36 and the matrix material 34 with the scattering particles 33 are shaped like a hood. The phosphor plate 36 can have a further matrix material in which the phosphor particles are embedded.

[0053] In the embodiment according to Fig. 4, a layer of a bonding agent 7 is located between the semiconductor chip 2 and the phosphor plate 36, as well as between the phosphor plate 36 and the matrix material 34 with the scattering particles 33. The individual components are secured to one another by the bonding agent 7, which is formed, for example, from a silicone. A thickness D of the layers of the bonding agent 7 is, for example, at most 20 µm or at most 10 µm. The matrix material 34 with the scattering particles 33 optionally does not project beyond the semiconductor chip 2 in a lateral direction.

[0054] The conversion element 3 can be surrounded by a potting compound 6. Such a potting compound 6 can also be present in all other embodiments. The potting compound 6 is, for example, transparent, such as made of silicone, or contains additives for light scattering or light filtering.

[0055] In the embodiment according to Fig. 5, the semiconductor component 1 comprises a semiconductor chip 2a emitting in the blue spectral range and a semiconductor chip 2b emitting in the red spectral range, wherein the semiconductor chips 2a, 2b are mounted together on the carrier 5. The conversion element 3 is arranged downstream of the semiconductor chip 2a emitting in the blue spectral range. The semiconductor chip 2b emitting in the red spectral range can be free of a scattering agent.

[0056] According to Fig. 6, the conversion element 3 is arranged downstream of the semiconductor chips 2a, 2b, which can also be a semiconductor chip emitting in the blue spectral range and a semiconductor chip emitting in the red spectral range.

[0057] In Fig. 7 shows the changes in the color coordinates Δc for different compositions of the conversion element, depending on the temperature T in degrees Celsius. x and Δc y outlined in Fig. 7A for the red color coordinate c xand in Fig. 7B for the green color coordinate c y , based on the CIE standard chromaticity diagram.

[0058] The curves marked with a in the Fig. 7A and Fig. 7B denote a conversion medium that has no scattering particles. Curves b, c, and d each refer to conversion elements 3, as described above. All curves a, b, and d have a weight fraction of 10% of a phosphor, which is an orthosilicate emitting in the green spectral range. The weight fraction of the scattering particles, which are formed from silicon dioxide, is 0% for curve a, approximately 5% for curve b, approximately 10% for curve c, and approximately 12.5% for curve d.

[0059] In Fig. 7 it can be seen that the color coordinates c x , c yin curve a and that a shift can be reduced by adding the scattering particles towards higher temperatures, see curves b, c, d.

[0060] The color shift Δc x , Δc y refers in each case to the mixed radiation emitted by the semiconductor component 1, composed of the radiation emitted directly by the semiconductor chip 2 and the radiation converted by the conversion element 3.

[0061] In Fig. 8 is an efficiency E versus a color shift Δc x + Δc y for various scattering particles. In Fig. 8 shows only the spectral shift of a white light-emitting semiconductor component 1 due solely to the change in the refractive index of the matrix material. The refractive index of the matrix material is reduced by approximately 0.035, corresponding to a temperature change from 25 °C to 120 °C. A change in efficiency E due to temperature changes of the semiconductor chip is shown in Fig. 8 not taken into account. Fig. 8 thus refers only to the change in efficiency E due to the influence of the refractive index change between the matrix material and the scattering particles at the specified temperature change from 25 °C to 120 °C.

[0062] Curve a refers to scattering particles with a refractive index of approximately 1.8 of a conventional diffuser. Increasing the diffuser concentration in the matrix material, with a refractive index of approximately 1.5, only results in a reduction in efficiency E, but no significant shift in the color coordinate.

[0063] Curve b refers to silicon dioxide spheres with an average diameter of 1 µm as scattering particles. The silicon dioxide spheres have a refractive index of 1.46 at room temperature, and the associated matrix material, which is silicone, has a refractive index of 1.41, also at room temperature. The individual points on curve b refer to a weight fraction of scattering particles of 0%, 1%, 2%, 5%, and 10%. The efficiency E decreases with increasing weight fraction of scattering particles, but the color shift increases. A preferred color shift of approximately 0.02 is achieved at a weight fraction of approximately 1%.

[0064] Curve c uses the same scattering particles as curve b, but the matrix material, which is silicone, has a higher refractive index of 1.46 at room temperature. It can be seen that the color coordinate change is approximately the same as in curve b, but the efficiency E decreases less sharply.

[0065] In curve e, silicon dioxide spheres with a refractive index of 1.46 at 300 K are added to a silicone matrix material with a refractive index of 1.41 at room temperature, with a weight fraction of 2%. Curve e represents the different average diameters of the scattering particles. A particularly favorable ratio of efficiency E to color shift is obtained, especially with an average scattering particle size of 500 nm.

[0066] Curve d refers to the same scattering particles as curve b, but a matrix material, which is a silicone, with a refractive index of 1.51, with a tolerance of at most 0.005, or at most 0.01, or at most 0.03, is used at room temperature. The refractive index of the matrix material is therefore higher at room temperature than the refractive index of the scattering particles. Thus, the refractive index difference between the matrix material and the scattering particles decreases with increasing temperature, and the color coordinate shifts towards blue with temperature changes. All features regarding the conversion element, the carrier, the housing, the encapsulation, and / or the semiconductor chip, as stated in connection with the above-mentioned exemplary embodiments, can in principle also be applied to the embodiment according to curve d.

Claims

[1] Optoelectronic semiconductor component (1) with - at least one optoelectronic semiconductor chip (2) for generating electromagnetic radiation, and - a conversion element (3) which is designed to convert at least part of the radiation emitted by the semiconductor chip (2) into radiation of a different wavelength, where - the conversion element (3) comprises at least one phosphor and scattering particles (33), - the conversion element (3) comprises at least one matrix material (34) in which at least the scattering particles (33) are embedded, - a refractive index difference between the matrix material (34) and a material of the scattering particles (33) at a temperature of 300 K is at most 0.06 and at 400 K at least 0.075, and - the refractive index difference is greater at a temperature of 380 K than at 300 K, - wherein the phosphor is in the form of particles and is embedded in the matrix material (34) together with the scattering particles (33), - wherein the phosphor and the scattering particles (33) are mixed, the scattering particles having an average diameter of at least 400 nm and at most 10 µm, - wherein the weight proportion of the scattering particles (33) in the conversion element (3) is between 0.5% and 50%, - wherein the weight fraction of the phosphor is between 5% and 20% inclusive and the particles of the phosphor have an average diameter of between 5 µm and 40 µm inclusive, which is larger than the average diameter of the scattering particles (33). [2] Optoelectronic semiconductor component (1) according to the preceding claim, wherein the material of the scattering particles (33) is or comprises one of the following materials: silicon dioxide, a glass, quartz, silicon nitride, a metal fluoride. [3] Optoelectronic semiconductor component (1) according to the preceding claim, wherein the matrix material (34) is a silicone or a silicone-epoxy hybrid material and has a refractive index between 1.38 and 1.54 inclusive. [4] Optoelectronic semiconductor component (1) according to one of the preceding claims, in which the phosphor and the scattering particles (33) are unmixed, wherein a distance (D) between the scattering particles (33) and the phosphor is at most 250 µm. [5] Optoelectronic semiconductor component (1) according to one of the preceding claims, in which the phosphor is the only phosphor and consists of exactly one of the following materials: - a green-emitting orthosilicate with the molecular formula (Ba x , Sr y , Ca 1-x-y ) 2-z Eu z SiO4 with 0.25 ≤ x < 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1, - a green-emitting nitrido-orthosilicate with the molecular formula (Ba x , Sr y , Ca 1-x-y ) 2-z Eu z Si(O a , N (0,67-0,67a) )4 with 0.25 ≤ x < 1, 0 ≤ y ≤ 0.75, 0 < z ≤ 0.5 and 0 < a < 1. [6] Optoelectronic semiconductor component (1) according to one of the preceding claims, in which the conversion element (3) comprises a first phosphor and a second phosphor, wherein the first phosphor is intended to emit green and the second phosphor is intended to emit red or red-orange. [7] Optoelectronic semiconductor component (1) according to one of the preceding claims, wherein - the scattering particles (33) have an average diameter of between 2.5 µm and 8.5 µm, - the material of the scattering particles (33) is silicon dioxide, - the matrix material (34) has a refractive index between 1.36 and 1.48 inclusive, - the semiconductor chip (2) is designed to generate blue light, - the weight proportion of the scattering particles (33) is between 6% and 15%, and - the conversion element (3) comprises the first and the second phosphor, which are mixed together with the scattering particles (33) into the matrix material (34). [8] Optoelectronic semiconductor component (1) according to one of the preceding claims, wherein - the scattering particles (33) have an average diameter of between 400 nm and 1.5 µm, - the material of the scattering particles (33) is silicon dioxide, - the matrix material (34) has a refractive index between 1.39 and 1.48 inclusive, - the semiconductor chip (2) is designed to generate blue light, - the weight proportion of the scattering particles (33) is between 0.75% and 6%, - the conversion element (3) comprises the first and the second phosphor, which are combined in a ceramic phosphor plate (36), - the scattering particles (33) are not incorporated into the phosphor plate (36), and - the phosphor plate (36) is located between the semiconductor chip (2) and the matrix material (34) with the scattering particles (33). [9] Scattering means for a conversion element (3) which is designed to convert radiation emitted by a semiconductor chip (2) into radiation of a different wavelength, comprising - a matrix material (34), and - scattering particles (33) embedded in the matrix material (34), wherein a refractive index difference between the matrix material (34) and a material of the scattering particles (33) is smaller at a temperature of 300 K than at a temperature of 380 K. [10] Scattering means according to claim 9, wherein the scattering particles (33) have an average diameter of between 250 nm and 20 µm inclusive. [11] Scattering means according to one of the preceding claims 9 or 10, wherein a weight proportion of the scattering particles (33) in the conversion element (3) is between 0.5% and 50% inclusive. [12] Scattering means according to one of the preceding claims 9 to 11, which comprises a phosphor, wherein the phosphor is in the form of particles and is embedded in the matrix material (34) together with the scattering particles (33), wherein the phosphor and the scattering particles (33) are mixed. [13] Scattering means according to the preceding claim, in which a weight proportion of the phosphor is between 5% and 20% inclusive and the particles of the phosphor have an average diameter between 5 µm and 40 µm inclusive, which is larger than the average diameter of the scattering particles (33). [14] Scattering means according to one of the preceding claims 9 to 13, wherein the refractive index difference at 300 K is at most 0.06 and at least 0.075 at 400 K.

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