Light-emitting device and lamp

Abstract

The invention relates to a light-emitting device (1) comprising at least two LED units (Li, where i = 1, 2, 3) each having: at least one LED chip (Ci) for generating primary light (Pi) with a primary spectrum; and a conversion component (Ki) for converting the primary light (Pi) into secondary light (Si) with a secondary spectrum that has a greater spectral width than the primary spectrum. The secondary spectra of each of the at least two LED units (Li) are different from one another.

Description

[0001]Light-emitting device and luminaire This patent application claims priority from German patent application DE 102023206079.5, the content of which is incorporated herein by reference. The present invention relates to a light-emitting device, in particular in the form of an LED package. The invention also relates to a luminaire having at least one such light-emitting device. Light-emitting devices in the form of LED packages are known from prior use. These use one or more LED chips to generate light. Due to the narrow-band radiation characteristics of LED chips, the generation of white light and mixed colors requires special precautions. For example, it is known to combine LED chips of different colors. In particular, the use of red, green, and blue LEDs in an LED package to generate white light is known.However, these so-called RGB LED packages, or RGB LEDs for short, have an inhomogeneous spectrum, which leads to poorer color rendering values. In particular for generating white light, it is also known to convert primary light from an LED chip into, for example, white secondary light using a light-converting material. However, the resulting spectrum is predetermined by the particular light-converting material used and is therefore not adjustable. It is an object of the present invention to improve a light-emitting device, in particular to provide a light-emitting device which has a radiation spectrum with high color rendering quality and a high degree of flexibility with regard to the radiation spectrum. This object is achieved by a light-emitting device according to claim 1. The light-emitting device, also called a light emitter, is in particular an LED package.It has at least two LED units. The at least two LED units each have at least one LED chip for generating primary light with a primary spectrum and a conversion component for converting the primary light into secondary light with a secondary spectrum, wherein the secondary spectrum has a greater spectral width than the primary spectrum. The secondary spectra of different ones of the at least two LED units are different. The device combines the advantages of individual LED units with the broadband radiation characteristics of the respective conversion component. This enables more homogeneous and thus more color-true color mixtures without being restricted to the spectrum of a light-converting material. The secondary light of the at least two LED units overlaps to form radiation from the light-emitting device.In other words, the secondary spectra of the at least two LED units overlap to form an emission spectrum. The emission light with the emission spectrum is the light emitted by the device and ultimately perceived by the user. The emission spectrum covers, in particular, at least part of the visible light. The emission spectrum can also include parts of the infrared range and / or UV range, depending on the application. The emission spectrum is preferably in the visible wavelength range, in particular between 380 nm and 780 nm. In particular for generating white light, the emission spectrum preferably covers at least 50% of the visible wavelength range, in particular at least 75% of the visible wavelength range. The secondary spectra differ. They cover different sub-ranges of the wavelength range covered by the emission spectrum.The secondary spectra are preferably in the visible wavelength range, in particular between 380 nm and 780 nm. The primary light can be visible light (in particular between 380 nm and 780 nm). The primary light can also have other wavelengths, in particular in the UV wavelength range. The primary light of an LED unit is converted into secondary light by the respective conversion components. The wavelengths of the primary light are preferably selected such that good absorption and re-emission by the respective conversion component is ensured. It is also possible to select the primary light such that the primary spectrum lies entirely within the spectral range of the secondary spectrum. False colors in the emission spectrum resulting from unconverted primary light are thereby particularly reliably avoided. The spectral width of the secondary spectrum is greater than that of the respective primary spectrum.The spectral width is in particular an emission line width, in particular a full width at half maximum (FWHM). Due to the use of LED chips, the primary light is particularly narrow-band. The respective primary spectra can, for example, have a full width at half maximum between 5 nm and 20 nm, for example a full width at half maximum of approximately 15 nm. The spectral width, in particular the full width at half maximum, of the secondary spectra is preferably greater than 15 nm, in particular greater than 20 nm, in particular greater than 30 nm. A particularly suitable range for the spectral width, in particular the full width at half maximum, of the respective secondary spectra is between 15 nm and 120 nm. The conversion components in particular comprise at least one light-converting material.To achieve different secondary spectra, the conversion components of the respective LED units, in particular the at least one light-converting material contained therein, preferably differ. The conversion component, in particular the light-converting material contained therein, absorbs the primary light and emits the secondary light. Suitable conversion components comprise, in particular, light-converting material that exhibits luminescence, in particular photoluminescence, for example fluorescence or phosphorescence. Such materials are also referred to as phosphors. Suitable light-converting materials can be selected depending on the desired secondary spectrum. Examples of suitable phosphors are, in particular: ^^^^^^^. ^ : ^^ ^^ , (^^, ^^)^^^^^^ ^ : ^^ ^^ , ^^ ^ ^ ^ : ^^ ^^ , ^^ ^ ^^ ^^^ ^^ ^ ^ ^ , ^^ ^^^ ^^^ ^^^ ^ , ^^^^^ ^ : P^ ^^ , ^^ ^^ , ^^ ^ ^^ ^ ^ ^ : ^^ ^^ , ^^^^ ^ ^ ^ : ^^ ^^ , ^^^^ ^ ^ ^ : ^^ ^^ , ^^ ^ ^^ ^ ^ ^^ : ^^ ^^ , ^^^: ^^ ^^ , ^^ ^ ^^ ^ ^ ^^ : ^^ ^^ and / or Particularly suitable conversion components include light-converting material in the form of so-called quantum dots, for example cadmium-containing or cadmium-free quantum dots. Examples of suitable materials for the quantum dots are CdSe / ZnS, InP / ZnS, ZnSe / ZnS, and / or perovskites, in particular CsPbX3, where X is selected from the group consisting of Cl, Br, and / or I. Quantum dots are nanoparticles that exhibit different emission spectra depending on their diameter and / or starting material. The diameter can be, for example, between 1 nm and 20 nm, in particular between 1 nm and 12 nm, especially for quantum dots based on CdSe. Depending on the size and / or starting material, the emission spectrum, in particular a maximum position and / or spectral width, can thus be easily and efficiently adjusted.By suitable mixtures of quantum dots of different diameters, in particular the spectral width of the achieved secondary spectrum can be adjusted. The light-emitting device has at least two LED units. The light-emitting device can have more than two LED units, in particular three, in particular four, in particular five or more LED units. An LED unit has at least one LED chip for generating primary light. An LED unit can also have more than one LED chip. Different LED chips of an LED unit can generate primary light with the same primary spectrum or primary light with different primary spectra. The generation of different primary spectra can be used, for example, to excite different light-converting materials of the corresponding conversion component. The secondary spectra of different of the at least two LED units differ.The secondary spectra of different LED units can, in particular, have different maximum and / or different center wavelengths. The secondary spectra can, in particular, cover different ranges of the emission spectrum. Different secondary spectra can have overlapping spectral ranges. It is also possible for different secondary spectra to have maxima and / or center wavelengths that are close to one another or the same. Different secondary spectra can, in particular, have the same color valence. If appropriate, the secondary spectra can differ in their respective spectral widths. In this way, it is possible to cover spectral ranges of different widths with the respective secondary spectra. A device according to claim 2 is particularly advantageous with regard to the achievable color mixtures.Different color valences of the secondary spectra of the LED units allow a mixing of the respective corresponding colors. Different color valences are to be understood in particular in such a way that the respective secondary spectra correspond to different colors perceptually for an observer, in particular different primary colors. Different color valences can be caused by different spectral profiles. In particular, the respective secondary spectra can have different maximum and / or center wavelengths. A device according to claim 3 enables particularly flexible mixing of the secondary spectra. In particular, any desired color mixtures of different color valences of the respective secondary spectra can be achieved.The independent control of the respective LED units can be achieved, for example, with the aid of an externally controlled power supply to the respective connections of the LED units, in particular their LED chips. The device, in particular the LED package, preferably has an integrated circuit (IC) for controlling the respective LED units. A device according to claim 4 enables particularly precise definition of the emission spectrum, in particular a particularly homogeneous light color. Incorrect colors in the emission spectrum, which are due to unconverted primary light, are thereby particularly reliably avoided. A device according to claim 5 is particularly advantageous and flexible. With the aid of the at least three LED units, which cover the primary colors of a color system, the colors of the respective color system can be generated with high quality. In particular, high-quality white light generation is possible.Particularly preferably, the at least three LED units are independently controllable, whereby the color generated here can be flexibly adapted within the color space of the respective color system. The generated color of the color system and / or producible white light has a homogeneous mixture. This improves the characteristics of the color system, in particular a correlated color temperature (CCT) and / or a color rendering index (CRI). The primary colors covered by the secondary spectra can be the primary colors of any color system. For example, these can be the primary colors of the RGB color system: red, green, and blue. The reproduction of primary colors of other color systems using the secondary spectra is also possible. For example, the CMY color system with the primary colors cyan, magenta, and yellow can be used.Depending on the dimensionality of the color space assigned to the color system, three or more LED units can be provided. It is also possible to provide at least six LED units that cover the primary colors of at least two color systems. In this way, a primary color system or a secondary color system can be covered, which further increases the quality of color reproduction. For example, LED units can be provided to cover the primary colors of the RGB color system and the CMY color system. A device according to claim 6 enables particularly precise definition of the emission spectrum, in particular the light color of the light to be emitted. In particular, the primary spectra lie entirely within the spectral range of the respective secondary spectrum. The LED chips of the LED units can be selected depending on the respective color system. The LED chips can be RGB LEDs, for example.A device according to claim 7 is characterized by particularly good color rendering. The color rendering index can be determined, for example, according to the CIE standard color valence system 13.3 (1995). The achievable color rendering index can be dependent, in particular, on the respective spectral width of the secondary spectra of the LED units. The improved color rendering index is particularly evident when compared to the use of conventional RGB LEDs. These have a lower color rendering index of less than 70 due to the narrowband spectrum of the respective LED chips. In particular, the color rendering index of the radiation spectrum of the device is improved by at least 5%, in particular by at least 10%, in particular by at least 20%, compared to the emission characteristics when using LED chips of the corresponding primary color of the color system without respective conversion components.Alternatively or additionally, the radiation spectrum of the device preferably has a correlated color temperature that is below the correlated color temperature of RGB LEDs with a high, in particular corresponding, color rendering index. With RGB LEDs, the color temperature and a high color rendering index cannot typically be set simultaneously. If a high color rendering index is to be achieved with RGB LEDs, generally only a cool light of 7,000 K or more can be achieved. The radiation spectrum of the device can, in particular, have a correlated color temperature between 2,700 K and 6,500 K. The correlated color temperature can, in particular, depend on a spectral width of the respective secondary spectra. This makes it easy to adjust the correlated color temperature. In particular, the generation of neutral white light or warm white light is possible.A device according to claim 8 has particularly good color rendering, in particular particularly good white light quality. The spectral width can in particular be a half-width of the secondary spectra. By adjusting the spectral width, in particular the desired correlated color temperature and / or the color rendering index to be achieved can be influenced. The higher the spectral width, the more homogeneous the resulting color mixture, in particular with regard to the generation of white light. However, excessively high spectral widths lead to an overlap of the respective secondary spectra, so that a controlled generation of individual colors is difficult. The range of the spectral width of the secondary spectra between 15 nm and 120 nm, in particular between 20 nm and 120 nm, has proven particularly suitable. For the generation of white light, a spectral width of the secondary spectra between 60 nm and 120 nm is particularly advantageous.For the generation of colored light, a spectral width of the secondary spectra between 20 nm and 60 nm is particularly advantageous. A device according to claim 9 has proven to be particularly advantageous. The use of quantum dots as light-converting material is particularly suitable with regard to the adjustability of the spectral width of the secondary spectrum. By using quantum dots of different diameters, the spectral width of the respective secondary spectra can be flexibly and precisely adapted to the respective application. For example, different groups of quantum dots with respective average diameters can be used, wherein the average diameters of different groups are in particular different. By means of the respective proportions of the groups of quantum dots in the conversion component, their respective contribution to light conversion can in particular be adjustable.For example, quantum dots that emit light of different colors can be combined in the conversion component. The conversion components of several LED units, in particular of all LED units, preferably have quantum dots of different diameters. A device according to claim 10 enables particularly flexible generation and / or mixing of different secondary spectra. The different primary spectra of the LED chips of an LED unit can, for example, be selected such that different light-converting materials of the corresponding conversion component are excited thereby. The light conversion is particularly efficient. For example, quantum dots of different diameters contained in the conversion component can be excited using respective primary spectra.Preferably, two or more LED units, in particular all LED units, can each have a plurality of LED chips with different primary spectra. A device according to claim 11 enables particularly flexible and precise adjustment of the mixture of the different secondary spectra. Crosstalk is avoided by the respective shielding of the LED units. Excitation of the conversion component of other LED units by primary light and / or secondary light of an LED unit is reliably avoided. This makes it possible in particular to use individual LED units to generate the emitted light, for example by appropriate individual control. A device according to claim 12 particularly effectively avoids crosstalk between different LED units. The arrangement of the LED units in the respective recesses orCavities of the substrate enable effective shielding without the need for other structural measures, in particular separate shielding elements. In addition, the LED units are mechanically protected in the recesses of the substrate. The device is robust. A device according to claim 13 is robust and has a simple structure. Because the conversion component itself is an encapsulation for the respective LED chip, separate encapsulation is not necessary. The LED chip is protected in the encapsulation. In addition, the encapsulation prevents primary light from the respective LED chip from escaping past the conversion component to the outside and impairing the desired color mixing. Particularly preferably, the at least one conversion component can form an encapsulation of the respective LED chip in a corresponding recess of the substrate.As a result, the LED chip and the encapsulation are securely embedded in the recess. A device according to claim 14 enables a particularly space-saving arrangement of the conversion component on the respective LED chips. The LED chip is preferably coated with the conversion component over an entire exposed surface. The coating prevents primary light from the LED chip from escaping past the conversion component. It is a further object of the invention to improve a luminaire. This object is achieved by the luminaire according to claim 15. The luminaire has at least one light-emitting device as described above. The luminaire can have at least one or more corresponding LED packages. The advantages and optional features of the luminaire correspond to those of the device described above.Further features, advantages, and details of the invention will become apparent from the following description of exemplary embodiments with reference to the figures. These show: Fig. 1 schematically a first exemplary embodiment of a light-emitting device in the form of an LED package with three LED units, Fig. 2A an exemplary emission spectrum of a known RGB LED, Fig. 2B an exemplary emission spectrum of the LED package according to Fig. 1, Fig. 3A an exemplary color temperature index as a function of a spectral width of secondary spectra of the LED units of the LED package according to Fig. 1, Fig. 3B an exemplary color rendering index as a function of a spectral width of the LED units of the LED package according to Fig. 1, Fig. 3C the color rendering index according to Fig. 3B as a percentage improvement over a color rendering index of a known RGB LED, Fig. 4 schematically a further exemplary embodiment of a light-emitting device in the form of an LED package, Fig.5 schematically shows a further exemplary embodiment of a light-emitting device in the form of an LED package, and Figs. 6A to 6C show schematic emission spectra of quantum dots of different diameters and mixtures thereof. Corresponding parts, components, spectra, and / or other sizes are provided with the same reference numerals in Figs. 1 to 5. Details of the exemplary embodiments explained in more detail below can also represent an invention in themselves or be part of a subject matter of the invention. Fig. 1 schematically shows a first exemplary embodiment of a light-emitting device 1 in the form of an LED package. The LED package 1 has a substrate 2 on which a plurality of LED units Li are arranged. The index i = 1, 2, ... denotes here and below various LED units and associated (sub-)components, light spectra, and / or characteristics.In the illustrated embodiment, three LED units Li are shown, namely L1, L2, and L3, with their respective (sub-)components, light spectra, and parameters (with index i = 1, 2, 3). The LED units Li have an LED chip Ci for generating primary light P. i The LED units L i have a conversion component Ki for converting the respective primary light Pi into a secondary light Si. A primary spectrum of the primary light Pi is narrowband. The spectrum obtained with the help of the respective conversion component K i generated secondary light S ihas a secondary spectrum that has a greater spectral width than the primary spectrum. The resulting secondary spectra are therefore broader in bandwidth than the primary spectra that can be generated using the LED chips Ci. The spectral width of the secondary spectra can be quantified in particular as full width at half maximum (FWHM). The full width at half maximum of the secondary spectra is in particular in the range between 15 nm and 120 nm. The secondary light Si of the respective LED units Li has different secondary spectra, wherein the secondary spectra have color valences that correspond to the primary colors of a color system. In the exemplary embodiment shown, the color valences of the respective secondary spectra correspond to the primary colors red, green, and blue of the RGB color system.The secondary light Si of the LED units Li is superimposed to form an emitted light A with an emission spectrum that corresponds to the superposition of the respective secondary spectra. With the help of an integrated circuit 3, the LED units Li can be controlled independently of one another. This allows a mixture of the secondary spectra in the emitted light A and thus the resulting emission spectrum to be adjusted. By mixing the secondary light Si corresponding to the respective primary colors of the color system, the emitted light A can be generated with any color of the RGB color space, in particular white light. In the exemplary embodiment shown, the conversion components Ki are designed as encapsulation of the respective LED chips Ci. A light-converting material is contained in the encapsulation.To generate the respective, differing secondary spectra of the secondary light Si, the conversion components Ki comprise different light-converting materials and / or different mixtures of light-converting materials. Suitable light-converting materials are, in particular, so-called quantum dots, which may or may not contain cadmium, for example. Quantum dots are nanoparticles that absorb light and emit it at different wavelengths. The emitted wavelength depends on the diameter and / or the starting material of the respective quantum dot. This allows the secondary spectrum, in particular its spectral width, to be specifically and easily adjusted by selecting quantum dots of different diameters and / or different materials. The respective suitable diameter can depend on the material of the quantum dot.For example, the diameter can be selected from 1 nm to 20 nm, especially for CdSe-based quantum dots. The primary spectra of the primary light Pi of the respective LED chips Ci are less relevant. The primary light P. i can be selected to be the same or different for the different LED units Li. It is advantageous to select corresponding LED chips Ci whose primary light Pi is particularly well absorbed by the light-converting material of the respective conversion component Ki. The following is a concrete, purely exemplary example of a combination of LED chips C iand respective conversion components Ki specified: - The LED chip C1 of the LED component L1 has a primary spectrum of the generated primary light P1 with a maximum at approximately 385 nm. The conversion component K1 has a light-converting material in the form of quantum dots, which have good absorption below 450 nm, in particular efficient absorption at 385 nm, and whose secondary light S1 has a secondary spectrum with a maximum around 450 nm. The half-width is approximately 60 nm. The resulting color value corresponds to blue light. - The LED chip C2 of the LED component L2 has a primary spectrum of the generated primary light P2 with a maximum at approximately 450 nm. The conversion component K2 comprises a light-converting material in the form of quantum dots, which have good absorption below 500 nm, in particular efficient absorption at 450 nm, and whose secondary light S2 has a secondary spectrum with a maximum around 515 nm.The half-width is approximately 60 nm. The resulting color valence corresponds to green light. - The LED chip C3 of the LED components L3 has a primary spectrum of the generated primary light P3 with a maximum at approximately 450 nm. The conversion component K3 has a light-converting material in the form of quantum dots, which have good absorption below 650 nm, in particular efficient absorption at 450 nm, and whose secondary light S3 has a secondary spectrum with a maximum around 640 nm. The half-width is approximately 60 nm. The resulting color valence corresponds to red light. The following specifies another, purely exemplary example of a combination of LED chips Ci and respective conversion components Ki. The Ci LED chips are RGB LEDs, each with a primary spectrum in the red, green or blue color range.The conversion components Ki each comprise mixtures of quantum dots of different materials and / or different diameters, with the quantum dots, in particular their diameter, being selected such that the secondary spectra overlap with the respective primary spectra. In particular, the primary spectra lie entirely within a spectral range of the respective secondary spectra. The conversion components K. iThe spectral width is widened without unconverted portions of the primary light causing false colors. The mixture of different quantum dots, in particular quantum dots of different diameters, in the respective conversion components Ki enables a defined determination of the spectral width of the respective secondary spectra, as described in more detail below. A concrete, purely exemplary example of a purely exemplary combination of LED chips Ci and respective conversion components Ki is: - The LED chip C1 of the LED component L1 has a primary spectrum of red color. The conversion component K1 has a mixture of different quantum dots that emit red light or far-red light. The different quantum dots can be made of different materials and / or have different diameters.Example diameters of quantum dots, particularly those based on CdSe, can be: 6 nm (red light) or 12 nm (far-red light). - The LED chip C2 of the LED component L2 has a primary spectrum of green. The conversion component K2 has a mixture of different quantum dots that emit green light or orange light. The different quantum dots can be made of different materials and / or have different diameters. Example diameters of quantum dots, particularly those based on CdSe, can be: 3 nm (green light) or 5 nm (orange light). - The LED chip C3 of the LED component L3 has a primary spectrum of red. The conversion component K3 has a mixture of different quantum dots that emit blue light or green light.The different quantum dots can be made of different materials and / or have different diameters. Example diameters of quantum dots, particularly those based on CdSe, can be 2 nm (blue light) or 3 nm (green light). The emission spectrum generated using LED package 1 is illustrated in more detail with reference to Figs. 2A and 2B. In this figure, the normalized intensity I is plotted against the wavelength λ in nm for different spectra. Fig. 2A shows the intensities of the spectra of individual LEDs of a known RGB LED package. The respective spectra of the LEDs are labeled with the respective colors blue (B), green (G), and red (R). The spectra of the RGB LEDs have a small half-width. The resulting overall spectrum (dashed line) is white light, which, however, is not very homogeneous due to the small half-width of the individual spectra. In Fig.2B are the secondary spectra of the respective LED units L. i of the LED package 1 corresponding secondary light S ishown. Due to the respective conversion components Ki, the half-width of the secondary spectra is broadened compared to the use of RGB LEDs. In the exemplary embodiment shown, the half-width is 60 nm in each case. The radiation spectrum of the emitted light A resulting from the superposition of the respective secondary light Si therefore has a more homogeneous intensity over the visible wavelength range (plotted from 380 nm to 780 nm). As a result, characteristics of the emitted light, in particular a correlated color temperature and a color rendering index, are improved. The improvement in the characteristics of the emitted light A is explained in more detail with reference to Figs. 3A, 3B and 3C. The figures show various characteristics relating to the half-width FWHM of the secondary spectra of the respective LED units Li. Fig.3 shows the correlated color temperature CCT (from English: Correlated Color Temperature) in Kelvin over the FWHM in nanometers of the secondary spectra.The CCT of an entire spectrum of an RGB LED, as shown in Fig. 2A, for example, is represented as a cross "x". The ratio of the intensities of the individual R, G, and B LEDs to one another was selected such that the color rendering index of the RGB LED is optimized. The half-width of the RGB LED spectra is typically around 15 nm. The solid curve shows the CCT of the output light A of LED package 1. With increasing half-width, the CCT decreases while the ratio of the R, G, and B LEDs remains the same. While the RGB LED produces cold white light, the LED package 1 can easily produce neutral white and / or warm white output light A. Fig. 3B shows the color rendering index CRI (from English: Color Rendering Index) over the half-width FWHM. The CRI of the RGB LED is again marked by a cross “x” at the corresponding half-width of about 15 nm.The solid line shows the CRI for the output light A of the LED package 1 depending on the half-width (FWHM) of the respective secondary spectra. The CRI is significantly improved compared to the RGB LED. The CRI is above 70. The CRI is particularly improved for a spectral width of the secondary spectra between 20 nm and 120 nm. For the generation of white light, a spectral width of 60 nm to 120 nm is particularly advantageous. For the generation of colored light, the spectral width can be selected particularly between 20 nm and 60 nm. Fig. 3C shows the relative improvement in the CRI compared to the RGB LED. The improvement is at least 5%. Depending on the FWHM, the improvement can be 20% or more. Fig. 4 schematically shows another embodiment of an LED package 1a. Components that have already been described with reference to the embodiment in Fig.1 have the same reference numerals and will not be explained again in detail.Functionally corresponding, but structurally differently designed components bear corresponding reference numerals supplemented by "a". The conversion components Kai of the LED units Lai are designed as a coating of the LED chips Ci. The LED units Lai and the integrated circuit 3 are encapsulated in a common transparent encapsulation 4. The encapsulation 4 leads to a high structural integrity and stability of the LED package 1a. Fig. 5 shows a schematic view of a further embodiment of an LED package 1b. Components that have already been described with reference to the previous embodiments have the same reference numerals and will not be explained in detail again. Functionally corresponding, but structurally differently designed components bear corresponding reference numerals supplemented by "b". The LED units Lbi are introduced into corresponding recesses 5 of the substrate 2b. For this purpose, the LED chips C.i arranged at the bottom of the respective recess 5. The respective light conversion component Kb i serves as an encapsulation that fills the recess 5. Due to their arrangement in the recesses 5, the LED units Lbi are shielded from each other, so that neither primary radiation Pi nor secondary radiation Si can pass directly from one of the LED units Lbi into another. This prevents crosstalk. By appropriately controlling the LED units Lb ithe respective colors can be generated independently of one another without any admixtures occurring due to the unwanted excitation of the light conversion components Kbi of other LED units Lbi. The color rendering is particularly precise. The conversion components Ki of the LED units Li can have mixtures of quantum dots of different diameters. The effect of mixing quantum dots of different diameters is explained in more detail using Figures 6A to 6C. Fig. 6A shows a schematic view of the emission spectra of quantum dots with respective diameters D1 to D4. Here, the intensity I is plotted against the wavelength λ. For diameters D1 to D4, the following applies: D1 < D2 < D3 < D4. As can be seen from Fig. 6A, the emission spectrum of the quantum dots shifts towards longer wavelengths λ with increasing diameter.It was recognized that the mixture of quantum dots of different diameters can be used to adjust the spectral width of the conversion component K. For example, Fig. 6B shows an emission spectrum of a conversion component K (dashed line) which has a mixture of quantum dots of different diameters D1 and D2. Fig. 6C shows an example of the emission spectrum of a conversion component K (dashed line) which has a mixture of quantum dots with different diameters D1, D2 and D3. Depending on the mixture of the quantum dots, the spectral width of the conversion component K and thus the secondary spectrum of the respective LED unit L can be precisely and flexibly adjusted. The conversion components K shown in Figures 6B and 6C, for example, show mixtures of the quantum dots with a mixing ratio of 1:1.It is also possible to use different mixing ratios of the respective quantum dots of different diameters in order to adapt the spectral width, in particular the secondary spectrum of the respective conversion component K, more precisely to the respective application.

Claims

Patent claims 1. Light-emitting device, in particular LED package, comprising at least two LED units (L i ; La i ; Lb i ), each comprising - at least one LED chip (Ci) for generating primary light (Pi) with a primary spectrum and - a conversion component (Ki; Kai; Kbi) for converting the primary light (Pi) into a secondary light (Si) with a secondary spectrum that has a greater spectral width than the primary spectrum, wherein the secondary spectra of different ones of the at least two LED units (Li; Lai; Lbi) are different.

2. Light-emitting device according to claim 1, characterized in that the secondary spectra of the different LED units (L i ; La i ; Lbi) have different color valences.

3. Light-emitting device according to one of the preceding claims, characterized in that the at least two LED units (L i ; La i ; Lb i) can be controlled independently of each other to set a mixture of the secondary spectra of at least two LED units (L i ; La i ; Lb i ), in particular by means of an integrated circuit (3) of the light-emitting device (1; 1a; 1b).

4. Light-emitting device according to one of the preceding claims, characterized in that the primary light (P i ) of the respective LED chips (C i) of the at least two LED units (Li; Lai; Lbi) is selected such that the primary spectrum lies completely in the spectral range of the respective secondary spectrum.

5. Light-emitting device according to one of the preceding claims, characterized by at least three LED units (Li; Lai; Lbi) whose secondary spectra have color valences that correspond to the primary colors of a color system.

6. Light-emitting device according to claim 5, characterized in that the LED chips (Ci) of the respective LED units (Li; Lai; Lbi) emit primary light (Pi) that corresponds to the primary colors of the respective color system.

7. Light-emitting device according to claim 5 or 6, characterized by a color rendering index (CRI) of a radiation spectrum obtained by superimposing the secondary spectra of over 70, in particular over 75, in particular over 80. 8.Light-emitting device according to one of the preceding claims, characterized in that a spectral width of the secondary spectra is between 15 nm and 120 nm.

9. Light-emitting device according to one of the preceding claims, characterized in that the conversion component (K i ; Ka i ; Kb i ) at least one LED unit (Li; Lai; Lbi) has quantum dots of different diameters.

10. Light-emitting device according to one of the preceding claims, characterized in that at least one LED unit (Li; Lai; Lbi) has a plurality of LED chips (C i) whose primary spectra differ.

11. Light-emitting device according to one of the preceding claims, characterized in that the LED units (Li; Lai; Lbi) are shielded from one another in such a way that light from one LED unit (Li; Lai; Lbi) does not directly enter the conversion medium (Ki; Kai; Kbi) of another LED unit (Li; Lai; Lb i ) can radiate.

12. Light-emitting device according to claim 11, characterized in that the LED units (Li; Lai; Lbi) are arranged in respective recesses (5) of a substrate (2b).

13. Light-emitting device according to one of the preceding claims, characterized in that at least one of the conversion components (Ki, Kbi) forms an encapsulation containing a light-converting material for the respective LED chip (Ci).

14. Light-emitting device according to one of the preceding claims, characterized in that at least one of the conversion components (Ka i ) is applied as a coating to the respective LED chip (Ci).

15. Luminaire with at least one light-emitting device (1; 1a; 1b) according to one of the preceding claims.

Images