PHOSPHOR, ILLUMINATION DEVICE AND USE OF AN ILLUMINATION DEVICE

Abstract

A luminescent material may include the formula (MB) (TA).sub.32x(TC).sub.1+2xO.sub.44xN.sub.4x:E where 0<x<0.875. TA may be selected from a group of monovalent metals, such as Li, Na, Cu, Ag, and combinations thereof. MB may be selected from a group of divalent metals including Mg, Ca, Sr, Ba, Zn, and combinations thereof. TC may be selected from a group of trivalent metals including B, Al, Ga, In, Y, Fe, Cr, Sc, rare earth metals, and combinations thereof. E may be selected from a group including Eu, Mn, Ce, Yb, and combinations thereof.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. A phosphor having the formula (MB)Li.sub.2Al.sub.2O.sub.2N.sub.2:E where MB is selected from a group of divalent metals consisting of Mg, Ca, Sr, Ba, Zn, and combinations thereof; and wherein E is selected from a group consisting of Eu, Mn, Ce, Yb, and combinations thereof.

5. The phosphor as claimed in claim 4, which emits electromagnetic radiation in the red spectral region.

6. The phosphor as claimed in claim 4, which has an emission spectrum having a maximum peak wavelength of 614 nm+/10 nm and/or a half-height width of less than 60 nm.

7. The phosphor as claimed in claim 6, wherein the half-height width is less than 55 nm.

8. The phosphor as claimed in claim 4, wherein the phosphor does not crystallize in the crystal structure of the UCr.sub.4C.sub.4 type.

9. The phosphor as claimed in claim 4, wherein MB is Ca, Sr, Ba, or a combination thereof.

10. The phosphor as claimed in claim 4, wherein MB is Sr.

11. The phosphor as claimed in claim 4, wherein E is Eu.

12. The phosphor as claimed in claim 4, wherein the phosphor is excitable at least with radiation from the UV and/or blue spectral region.

13. A lighting device comprising a phosphor as claimed in claim 4.

14. The lighting device as claimed in claim 13 further comprising: a semiconductor layer sequence set up to emit electromagnetic primary radiation; and a conversion element which comprises the phosphor and at least partly converts the electromagnetic primary radiation to electromagnetic secondary radiation.

15. The lighting device as claimed in claim 14, wherein the phosphor fully converts the electromagnetic primary radiation to electromagnetic secondary radiation, such that the overall radiation from the lighting device is selected from the red wavelength range.

16. The lighting device as claimed in claim 14, wherein the conversion element comprises a second phosphor configured to emit radiation from the green spectral region, and a third phosphor configured to emit radiation from the red spectral region.

17. The lighting device as claimed in claim 14, in the form of a lamp for a motor vehicle.

18. The lighting device as claimed in claim 14, wherein the overall radiation from the lighting device is white mixed radiation.

19. A method for backlighting of display devices comprising the lighting device of claim 14.

20. The phosphor as claimed in claim 4, wherein the phosphor crystallizes in the tetragonal P4.sub.2/m space group.

21. The phosphor as claimed in claim 4, wherein MB is Sr and E is Eu such that the phosphor has the formula SrLi.sub.2Al.sub.2O.sub.2N.sub.2:Eu.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0083] In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the illumination apparatus. In the following description, various aspects are described with reference to the following drawings, in which:

[0084] FIG. 1 shows an emission spectrum (bulk sample) in one embodiment;

[0085] FIG. 2 shows the Kubelka-Munk function depending on the wavelength in one embodiment;

[0086] FIG. 3 shows the relative intensity depending on the temperature of comparative examples and working examples;

[0087] FIG. 4 shows the crystal structure in one embodiment;

[0088] FIG. 5 shows simulated x-ray powder diffractograms in a comparative example and working example;

[0089] FIGS. 6A to 6C show the crystallographic data in one embodiment;

[0090] FIGS. 7A to 8G show the simulated emission spectra and corresponding data for comparative examples and working examples;

[0091] FIG. 8H shows color locus coordinates in a comparative example and working example;

[0092] FIGS. 9 and 10 show x-ray powder diffractograms of comparative examples and working examples;

[0093] FIG. 11 shows emission bands of comparative examples and working examples;

[0094] FIG. 12 shows the photometric radiation equivalent of a comparative example and working example; and

[0095] FIGS. 13 to 15 each show a schematic side view of a lighting device in one embodiment.

DETAILED DESCRIPTION

[0096] In the working examples and figures, identical elements or elements of the same type or having the same effect may each be given the same reference numerals. The elements shown and their size ratios should not be regarded as being to scale. Instead, individual elements, for example layers, parts, components and regions, may be shown in oversized form for better representability and/or for better understanding.

[0097] The phosphor has the general formula (MB)Li.sub.32xAl.sub.1+2xO.sub.44xN.sub.4x:E where MB is selected from a group of divalent metals including magnesium, calcium, strontium, barium, zinc and combinations thereof. E is selected from a group including europium, manganese, cerium, ytterbium and combinations thereof. 0<x<0.875.

[0098] In particular, x=0.5, MB=strontium and E=europium, resulting in the working example B1 having the formula SrLi.sub.2Al.sub.2O.sub.2N.sub.2:Eu. Working example B1 can be produced by a solid-state reaction. For this purpose, the starting materials, such as strontium nitride, aluminum nitride, aluminum oxide, lithium nitride and europium nitride, may be blended in the ratios (table 1), molar amounts and/or weights stated hereinafter.

TABLE-US-00001 TABLE 1 Starting materials Molar amount n/mmol Mass m/g Sr.sub.3N.sub.2 15.26 4.438 AlN 30.83 1.264 Al.sub.2O.sub.3 30.83 3.143 Li.sub.3N 30.83 1.074 Eu.sub.2O.sub.3 0.23 0.081

[0099] The starting materials may be mixed and introduced, for example, into a nickel crucible. Subsequently, they can be heated to a temperature of between 700 C. and 1000 C., such as a temperature of 750 C. to 850 C., for example 800 C. The heating can be effected in a stream of 7.5% hydrogen in nitrogen.

[0100] Subsequently, the temperature can be maintained over a period of 1 hour to 400 hours, for example 5 hours to 150 hours, for example 100 hours. The result is the phosphor of working example B1.

[0101] As an alternative to the process already described, the phosphor can also be prepared by solid-state synthesis of the starting materials listed in table 2 in the amounts specified by way of example. For this purpose, the starting materials can be introduced into a tantalum ampoule and heated at a heating rate of 180 C. per hour to 800 C., kept at 800 C. for 100 hours, then cooled a at cooling rate of 6 C. per hour to 500 C., and then, for example, the oven can be switched off so that the system cools down to room temperature.

##STR00001##

TABLE-US-00002 TABLE 2 Starting materials Mass m/mg Sr.sub.3Al.sub.2O.sub.6 97.34 LiN.sub.3 23.09 Li (flux) 16.37 Eu.sub.2O3 0.83

[0102] FIG. 1 shows an emission spectrum of working example B1 as a bulk sample. What is shown is the relative intensity I.sub.rel depending on the wavelength in nm. The sample was excited with primary radiation at a wavelength of 460 nm. Working example B1 shows red emission. The emission spectrum shows a single peak with a small half-height width and a peak maximum of about 616 nm. The half-height width of the emission is less than 55 nm. The dominant wavelength is 605 nm and CIE-x: 0.644 and CIE-y: 0.352.

[0103] Owing to the short dominant wavelength in combination with the small half-height width and the associated good overlap with the human eye sensitivity curve, working example B1 has a high photometric radiation equivalent of 232 lm/W.sub.OPT. This high efficiency, combined with the red color locus, in the case of use of working example B1 in a lighting device, leads to a highly efficient lighting device having very good color reproduction, especially for saturated red shades.

[0104] FIG. 2 shows the Kubelka-Munk function. What is shown is the normalized KMF (KMF=(1R.sub.inf).sup.2/2R.sub.inf) depending on the wavelength in nm of the first working example B1. The Kubelka-Munk function shows that working example B1 has absorption both in the UV region and in the blue and green spectral region. This means that the luminescence of working example B1 can be excited by means of UV, blue and green light, and so this working example B1 or the phosphor is of excellent usability for a conversion LED with blue primary radiation.

[0105] FIG. 3 shows the thermal quenching characteristics for working example B1 and other conventional phosphors. What is shown is the relative intensity I.sub.rel (based in each case on the intensity at 25 C.) depending on the temperature T in C. It is apparent from the curves that working example B1 is comparable to the thermal quenching of YAG:Ce, which is conventionally used for white conversion LEDs. At suitable temperatures, working example B1 actually shows better performance than the other red-emitting conventional phosphors, for example of the M.sub.2Si.sub.5N.sub.8:Eu type.

[0106] FIG. 4 shows the crystal structure of working example B1, viewed along the crystallographic c axis. The black spheres are Sr, the white units LiO.sub.3N tetrahedra and the hatched units AlON.sub.3 tetrahedra.

[0107] Single-crystal x-ray structure analysis on working example B1 shows that the new phosphor crystallizes in the tetragonal P4.sub.2/m space group. The crystal structure can be described as a superstructure of the UCr.sub.4C.sub.4 structure type. However, the phosphor crystallizes in a structure different than the UCr.sub.4C.sub.4 structure type. The Bravais lattices of these two structures are fundamentally different. The UCr.sub.4C.sub.4 structure can be described in the body-centered I4/m space group. Thus, it is possible to observe only those reflections that satisfy the condition h+k+l=2n, and so the sum total of the indices of the reflections is even. By comparison with the UCr.sub.4C.sub.4 type, there are no such conditions applicable to the primitive lattice of the working example described here. This leads to the existence of additional reflections, for example with the index 100 at about 11.11 2 for copper K1 radiation with an interplanar distance (d value) of about 7.96 . The different number of reflections is apparent from the different Bravais lattices.

[0108] FIG. 5 shows a comparison of simulated powder x-ray diffractograms for working example B1 (upper image) with the P4.sub.2/m space group and a hypothetical SrLi.sub.2Al.sub.2O.sub.2N.sub.2 (lower image) with a crystal structure of the UCr.sub.4C.sub.4 type with the I4/m space group. What is shown is the interplanar distance in . It is apparent from the figure that the phosphor described here, using the example of working example B1 here, does not crystallize in the same space group as UCr.sub.4C.sub.4, but crystallizes in the tetragonal P4.sub.2/m space group. Working example B1 described here shows a reduction in symmetry that leads to a higher degree of freedom of the atomic positions. This leads to two nonequivalent crystallographic tetrahedral centers, by contrast with the UCr.sub.4C.sub.4 type, in which all tetrahedral centers are of equivalent symmetry.

[0109] In the inventive SrLi.sub.2Al.sub.2O.sub.2N.sub.2, it is possible to determine two types of tetrahedron: LiO.sub.3N and AlN.sub.3O tetrahedra. Each type of tetrahedron forms a column along the crystallographic c axis in that multiple tetrahedra share common corners. Sharing of the corners with other types of tetrahedra results in a three-dimensional tetrahedral network with three different channels in the crystallographic c direction (pure LiO.sub.3N, pure AlN.sub.3O and mixed (LiO.sub.3N).sub.0.5(AlN.sub.3O).sub.0.5 channels). Only the channels surrounded by LiO.sub.3N and AlN.sub.3O tetrahedra are populated by strontium. Strontium is coordinated in the form of a slightly distorted Sr(O.sub.4,N.sub.4) cube.

[0110] Working example B1 described shows a half-height width of less than 50 nm. By contrast, for the hypothetical SrLi.sub.2Al.sub.2O.sub.2N.sub.2 in the UCr.sub.4C.sub.4 type, a half-height width of greater than 70 nm is to be expected.

[0111] FIGS. 6A to 6C show the crystallographic data of working example B1. What are shown are the empirical formula F, the formula weight m, the crystal system C, the space group S, the unit cell volume V.sub.c, the density d, the radiation R, the measurement range M, the number of reflections measured RT, the symmetry-independent reflections IR, the number of parameters NP, the population O. The crystal system C is tetragonal (tetr). The definition of the parameters a, c, T, Rint, R1, wR2, GooF, Uiso, U11 to U12 is known to those skilled in the art and will therefore not be elucidated further at this point.

[0112] FIG. 6B shows the atomic parameters of working example B1 and FIG. 6C the anisotropic deflection parameters of working example B1.

[0113] FIGS. 7A to 7D show the results of simulated LED spectra of working examples A1 to A10 and comparative examples. FIGS. 7A to 7D show a table of results that can also be referred to as FIG. 7. Owing to its dimensions, the table has been split into FIGS. 7A to 7D. The results labeled AX where X=1 to 10 show the working examples. The results labeled VX where X=1 to 7 show the comparative examples corresponding to the respective working examples AX.

[0114] It is observed that the working examples, by comparison with the corresponding comparative examples, have a higher photometric radiation equivalent (LER). The potential LER value is about 15% to 23% higher than in the case of the corresponding comparative example (cf., for example, rel. LER of A1 and V1).

[0115] The corresponding simulated total emission spectra of the working examples and comparative examples of FIGS. 7A to 7D are shown in FIGS. 8A to 8G.

[0116] FIGS. 8A to 8G each show the intensity I in arbitrary units a.u. depending on the wavelength in nm.

[0117] FIG. 8A shows the simulated emission spectra of working examples A1, A9, A10 and of comparative example V1.

[0118] FIG. 8B shows the simulated emission spectra of working example A2 and of comparative example V2.

[0119] FIG. 8C shows the emission spectra of working example A3 and of comparative example V3, and of working example A8.

[0120] FIG. 8D shows the simulated emission spectra of working example A4 and of comparative example V4.

[0121] FIG. 8E shows the simulated emission spectra of working example A5 and of comparative example V5.

[0122] FIG. 8F shows the simulated emission spectra of working example A6 and of comparative example V6.

[0123] FIG. 8G shows the simulated emission spectra of working example A7 and of comparative example V7.

[0124] Examples A1 to A6 and A8 to A10 produce white light with a color temperature of 3000 K, whereas working example A7 shows red light via full conversion.

[0125] Working example A7, by comparison with comparative example V7, shows a relative LER value 105% higher.

[0126] The color locus coordinates of working example A7 and comparative example V7 are shown in FIG. 8H. It is apparent from FIG. 8H that both examples are in the orange-red ECE color range for automobile applications. The ECE regulation is ECE-R48.

[0127] The phosphor shows improved luminescence efficiency compared to conventional red-emitting phosphors, for example CaAlSiN.sub.3:Eu or SrLiAl.sub.3N.sub.4:Eu.

[0128] The high colour, space coverage in backlighting devices in combination with the high luminescence efficiency is caused by the low half-height width of the phosphor. Moreover, the phosphor is producible at moderate temperatures, which enables inexpensive production.

[0129] By means of the simulated LED emission spectra shown in FIGS. 8A to 8H, it is possible to determine the potential efficiency (LER) in warm white LEDs. All simulations were conducted assuming an individually emitting semiconductor chip of wavelengths from the blue spectral region with a dominant wavelength between 448 nm and 453 nm. In addition, a combination of the green- to yellow-emitting garnet phosphor with working example B1 or conventional red-emitting phosphors, such as CaAlSiN.sub.3:Eu, was used.

[0130] The emission spectra were simulated for two applications either with a color rendering index R.sub.A of greater than 90 at a color temperature of 3000 K or with an R.sub.A of greater than 80 at 3000 K. A color locus at CCT3000 K at or close to Planck's curve was used for all examples. In addition, conventional phosphors such as YAG:Ce and/or CaAlSiN.sub.3:Eu were added to the mixture in order to improve the spectral properties for the application.

[0131] Working examples A8, A9 and A10 show this concept. Working example A8 is similar to working example A3, but additionally includes a yellow-emitting garnet phosphor (YAG:Ce). It is thus possible to adjust the CRI value and to increase the LER value for the warm white spectrum (+2%).

[0132] Working examples A9 and A10 are related to working example A1, except that these additionally include a red-emitting nitride phosphor (CaAlSiN.sub.3:Eu and SrLiAl.sub.3N.sub.4:Eu).

[0133] In this example, the addition of the red-emitting nitride phosphor produces a change in the R9 value. Working examples A9 and A10 show R9 values of not less than 50, whereas working example A1 shows an R9 value of 20.

[0134] This concept is not restricted to the working examples shown here. More particularly, it is also possible to use a total of more than three phosphors, for example four, five, six or more. Moreover, this concept is not restricted to the addition of garnet phosphors and/or nitride phosphors; instead, it is also possible to use any of the phosphors known to those skilled in the art to optimize the emission bands.

[0135] In addition, working example A7 and comparative example V7 show full conversion, and the lighting device, especially a light-emitting diode, has an orange-red overall emission spectrum. Working example A7 was simulated with working example B1, and comparative example V7 with CaAlSiN.sub.3:Eu. The target color locus within the ECE-R48 color box was chosen for all examples.

[0136] FIG. 9 shows simulated x-ray powder diffractograms of a working example B1 and of comparative examples X11 to X14. X11=SrLiAl.sub.3N.sub.4, X12=CaLiAl.sub.3N.sub.4, X13=Sr.sub.4LiAl.sub.11N.sub.4 and X14=Ca.sub.18.75Li.sub.10.5Al.sub.39N.sub.55.

[0137] What is shown is the diffraction intensity (counts, C) on the y axis depending on the interplanar distance d in on the x axis.

[0138] The phosphor shows a different crystal structure and hence a different reflection pattern in the x-ray powder diffractogram than comparative examples X11 to X14.

[0139] The new red-emitting phosphor shows an improved luminous efficiency (V.sub.s; V.sub.s=LER/683 lm/W) compared to comparative examples X11-X14 as a result of a significant blue shift in the emission band and the small half-height width FWHM of the emission band.

[0140] In relation to comparative example X11, the luminous efficiency (V.sub.s) is greater by a factor of 4 (39% compared to 10%), and so this phosphor has excellent usability for conversion elements for conversion LEDs.

[0141] Compared to comparative example X12, the phosphor thus has a luminous efficiency (V.sub.s) at least eight times higher.

[0142] FIG. 10 shows a comparison of powder diffractograms of the new phosphor (the upper image is the simulation from the crystallographic data of the single-crystal structure determination; the lower figure is the experimental curve).

[0143] What is shown is the diffraction intensity (counts, C) depending on the interplanar distance (d value) of working example B1. The simulated and experimental curves show excellent agreement, and so the phosphor described here, using the example of working example B1, crystallizes in the tetragonal P4.sub.2/m space group.

[0144] FIG. 11 shows emission spectra of comparative example and a working example L1. What is shown is the intensity I depending on the wavelength in nm. The solid line shows the new phosphor with an excitation wavelength of 460 nm (B1powder sample of compound SrLi.sub.2Al.sub.2N.sub.2O.sub.2; L1single grain of compound SrLi.sub.2Al.sub.2N.sub.2O.sub.2). The short-dashed curve shows the comparative example SrLiAl.sub.3N.sub.4:Eu.sup.2+, and the long-dashed curve shows the comparative example CaLiAl.sub.3N.sub.4:Eu.sub.2+.

[0145] Table 3 below shows the corresponding data, where .sub.dom represents the dominant wavelength, .sub.max the peak wavelength, x and y the color locus, E the luminous efficiency Vs, and FWHM the half-height width.

TABLE-US-00003 TABLE 3 .sub.dom/nm .sub.max/nm x; y E/V.sub.s FWHM/nm L1 606 614 0.651; 0.349 39% 48 SrLiAl.sub.3N.sub.4: Eu.sup.2+ 632 ~650 0.706; 0.294 ~10% ~50 SrLiAl.sub.3N.sub.4: Eu.sup.2+ * ~630 ~654 0.711; 0.289 <10% ~50 CaLiAl.sub.3N.sub.4: Eu.sup.2+ ~670 0.720; 0.280 ~60 CaLiAl.sub.3N.sub.4: Eu.sup.2+ * ~640 ~670 0.721; 0.279 <5% ~60 Sr.sub.4LiAlnN.sub.14: Eu.sup.2+ 624 ~670 0.698; 0.301 <10% ~85 Ca.sub.18.75Li.sub.10.5Al.sub.39N.sub.55: Eu.sup.2+ ~645 0.699; 0.300 ~15% 58 * Data were estimated using the original publication.

[0146] FIG. 11 and table 3 show clearly that the inventors have succeeded in providing a phosphor, where the emission of comparative examples X11 and X12, maintaining the narrow-band emission, has been shifted to a shorter wavelength. This has an associated dramatic effect on the efficiency of the new phosphor compared to X11 and X12 with retention of emission in the red spectral region.

[0147] FIG. 12 shows the photometric radiation equivalent (LER) of the inventive phosphor L1 and of comparative example Sr[LiAl.sub.3N.sub.4]:Eu.sup.2+. What is shown on the y axis is the LER in lm/W.sub.opt. It is apparent that the novel phosphor is about four times as efficient as the comparative example Sr[LiAl.sub.3N.sub.4]:Eu.sup.2+.

[0148] FIGS. 13 to 15 each show schematic side views of different embodiments of lighting devices described here, especially conversion LEDs.

[0149] The conversion LEDs of FIGS. 13 to 15 include at least one phosphor. In addition, one further phosphor or a combination of phosphors may be present in the conversion LED. The additional phosphors are known to those skilled in the art and are therefore not mentioned explicitly at this point.

[0150] The conversion LED according to FIG. 13 has a semiconductor layer sequence 2 disposed atop a substrate 10. The substrate 10 may, for example, be in reflective form. Disposed atop the semiconductor layer sequence 2 is a conversion element 3 in the form of a layer. The semiconductor layer sequence 2 has an active layer (not shown) which, in the operation of the conversion LED, emits primary radiation with a wavelength of 300 nm to 500 nm. The conversion element 3 is disposed in the beam path of the primary radiation S. The conversion element 3 includes a matrix material, for example a silicone, epoxy resin or hybrid material, and particles of the inventive phosphor 4.

[0151] For example, the phosphor 4 has an average particle size of 10 m. The phosphor 4 is capable of converting the primary radiation S in the course of operation of the conversion LED at least partly or fully to a secondary radiation SA in the red spectral region. In the conversion element 3, the phosphor 4 is distributed homogeneously in the matrix material within the scope of manufacturing tolerance.

[0152] Alternatively, the phosphor 4 may also be distributed in the matrix material with a concentration gradient.

[0153] Alternatively, the matrix material may also be absent, such that the phosphor 4 takes the form of a ceramic converter.

[0154] The conversion element 3 has been applied over the full area of the radiation exit face 2a of the semiconductor layer sequence 2 and the side faces of the semiconductor layer sequence 2, and is in direct mechanical contact with the radiation exit face 2a of the semiconductor layer sequence 2 and the side faces of the semiconductor layer sequence 2. The primary radiation S can also exit via the side faces of the semiconductor layer sequence 2.

[0155] The conversion element 3 may be applied, for example, by injection molding, injection compression molding or spray coating methods. In addition, the conversion LED has electrical contacts (not shown here), the formation and arrangement of which is known to those skilled in the art.

[0156] Alternatively, the conversion element may also have been prefabricated and may be applied to the semiconductor layer sequence 2 by means of a pick-and-place process.

[0157] FIG. 14 shows a further working example of a conversion LED 1. The conversion LED 1 has a semiconductor layer sequence 2 atop a substrate 10. The conversion element 3 has been formed atop the semiconductor layer sequence 2. The conversion element 3 takes the form of a platelet. The platelet may consist of particles of the inventive phosphor 4 that have been sintered together and hence be a ceramic platelet, or the platelet includes, for example, glass, silicone, an epoxy resin, a polysilazane, a polymethacrylate or a polycarbonate as matrix material with particles of the phosphor 4 embedded therein.

[0158] The conversion element 3 has been applied over the full area of the radiation exit face 2a of the semiconductor layer sequence 2. More particularly no primary radiation S exits via the side faces of the semiconductor layer sequence 2, and it exits predominantly via the radiation exit face 2a. The conversion element 3 may have been applied atop the semiconductor layer sequence 2 by means of a bonding layer (not shown), for example composed of silicone.

[0159] The conversion LED 1 according to FIG. 15 has a housing 11 with a recess. A semiconductor layer sequence 2 having an active layer (not shown) is disposed within the recess. In the operation of the conversion LED, the active layer emits a primary radiation S having a wavelength of 300 nm to 460 nm.

[0160] The conversion element 3 takes the form of an encapsulation of the layer sequence in the recess and includes a matrix material, for example a silicone, and a phosphor 4, for example SrLi.sub.2Al.sub.2N.sub.2O.sub.2:Eu. The phosphor 4 converts the primary radiation S in the operation of the conversion LED 1 at least partly to a secondary radiation SA. Alternatively, the phosphor converts the primary radiation S fully to secondary radiation SA.

[0161] It is also possible that the phosphor 4 in the working examples of FIGS. 13 to 15 in the conversion element 3 is spaced apart from the semiconductor layer sequence 2 or the radiation exit face 2a. This can be achieved, for example, by sedimentation or by applying the conversion layer atop the housing.

[0162] For example, by contrast with the embodiment of FIG. 15, the encapsulation may consist solely of a matrix material, for example silicone, with application, atop the encapsulation, spaced apart from the semiconductor layer sequence 2, of the conversion element 3 as a layer atop the housing 11 and atop the encapsulation.

[0163] The working examples and their features that have been described in conjunction with the figures may, in further working examples, also be combined with one another, even though such combinations are not shown explicitly in the figures. In addition, the working examples described in connection with the figures may have additional or alternative features according to the description in the general part.

[0164] While specific aspects have been described, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the aspects of this disclosure as defined by the appended claims. The scope is thus indicated by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

LIST OF REFERENCE NUMERALS

[0165] 1 lighting device or conversion LED [0166] 2 semiconductor layer sequence or semiconductor chip [0167] 2a radiation exit face [0168] 3 conversion element [0169] 4 phosphor [0170] 10 substrate [0171] 11 housing [0172] S primary radiation [0173] SA secondary radiation [0174] CCT correlated color temperature [0175] CRI color rendering index [0176] LED light-emitting diode [0177] LER light yield [0178] W watts [0179] lm lumens [0180] .sub.dom, .sub.d dominant wavelength [0181] .sub.peak, .sub.p peak wavelength [0182] ppm parts per million [0183] R9 color rendering index [0184] d distance [0185] L,L1;L2 . . . phosphor