Conversion material, particularly for a white or colored light souce comprising a semiconductor light source, a method for the production thereof, as well as a light source comprising said conversion material

Abstract

The invention relates to a conversion material, in particular for a white or colored light source comprising a semiconductor light source as primary light source, comprising a matrix glass that, as bulk material, for a thickness d of about 1 mm, has a pure transmission .sub.i of greater than 80% in the wavelength region from 350 to 800 nm and in the region in which the primary light source emits light, wherein the sum of transmission and reflection of the sintered matrix glass without luminophore is at least greater than 80% in the spectral region from 350 nm to 800 nm and in the spectral region in which the primary light source emits light.

Claims

1. A method for the production of a conversion material for a white or colored light source comprising a semiconductor light source as primary light source, the method comprising the steps of: providing a glass matrix comprising an aluminum borosilicate glass with an yttrium fraction; grinding the glass matrix into a glass powder with a grain size distribution of grain sizes d100.7 m, d503 m, and d90150 m; providing a luminophore powder; mixing the glass powder and the luminophore powder to form a mixture; pressing the mixture to form a pressed mixture; sintering the pressed mixture to provide the conversion material; and forming, after the sintering, a protective layer on an outer surface of the conversion material.

2. A method for the production of a conversion material for a white or colored light source comprising a semiconductor light source as primary light source, the method comprising the steps of: providing a glass matrix comprising a lanthanum borosilicate glass with a zinc fraction or an aluminum borosilicate glass with an yttrium fraction; grinding the glass matrix into a glass powder with a grain size distribution of grain sizes d100.7 m, d503 m, and d90150 m; providing a luminophore powder; mixing the glass powder and the luminophore powder to form a mixture; pressing the mixture to form a pressed mixture; sintering the pressed mixture to provide the conversion material, wherein the sintering comprises heating the pressed mixture at a rate of 1 K/min to 30 K/min to a target temperature; holding the heated, pressed mixture at the target temperature for a period of time of 0 to 60 min; and subsequently, cooling the heated, pressed mixture to room temperature.

3. A method for the production of a conversion material for a white or colored light source comprising a semiconductor light source as primary light source, the method comprising the steps of: providing a glass matrix comprising a lanthanum borosilicate glass with a zinc fraction or an aluminum borosilicate glass with an yttrium fraction; grinding the glass matrix into a glass powder with a grain size distribution of grain sizes d100.7 m, d503 m, and d90150 m; providing a luminophore powder; mixing the glass powder and the luminophore powder to form a mixture; pressing the mixture to form a pressed mixture; sintering the pressed mixture to provide a sintered body; and annealing, by a temperature-assisted treatment, the sintered body to provide the conversion material, wherein the annealing is a second sintering, wherein the annealing step is carried out at a pressure in a range from 250 to 2500 bar, and wherein the annealing step is carried out at a temperature such that a viscosity of the matrix glass lies in a range between h=10.sup.14 dPas and h=10.sup.6 dPas.

4. The method according to claim 1, wherein said sintering step is conducted either in a specific atmosphere supplied by a gas selected from the group of nitrogen, forming gas, and argon, or at a reduced pressure.

5. The method according to one of claims 1 to 4, wherein the luminophore powder has a grain size with a mean grain size diameter d50 between 1 m and 50 m.

6. The method according to claim 1 or claim 4, wherein the sintering step takes place after the pressing step, and wherein the sintering step further comprises a heating of the pressed mixture containing the glass matrix and the luminophore powder to a target temperature in the range between the softening temperature EW and the processing temperature V.sub.a of the glass matrix.

7. A method for the production of a conversion material for a white or colored light source comprising a semiconductor light source as primary light source, the method comprising: providing a glass matrix comprising a lanthanum borosilicate glass with a zinc fraction or an aluminum borosilicate glass with an yttrium fraction; grinding the glass matrix into a glass powder with a grain size distribution of grain sizes d100.7 m, d503 m, and d90150 m; providing an encapsulated luminophore powder comprising an organic protective layer; mixing the glass powder and the encapsulated luminophore powder to form a mixture; pressing the mixture to form a pressed mixture; and sintering the pressed mixture to provide the conversion material.

8. The method according to claim 7, wherein the step of providing the encapsulated luminophore powder comprises forming or depositing a protective layer on a luminophore powder by a process selected from the group consisting of a wet-chemical methods, a sol-gel method, a PVD method, and a CVD method.

9. The method according to claim 7, further comprising forming a protective layer on an outer surface of the conversion material.

10. The method according to claim 7, wherein the encapsulated luminophore powder comprises a luminophore powder having a mean grain size diameter between 1 m and 50 m.

Description

EXEMPLARY EMBODIMENTS OF THE PRODUCTION OF MATRIX GLASSES

Production Example 6

(1) The raw materials for the oxides are weighed, one or more refining agents, such as, for example, As.sub.2O.sub.3, are added, and subsequently well mixed. The glass quantity is fused at approximately 1330 C. in a discontinuous melting assembly and afterwards refined (1380 C.) and homogenized. At a pouring temperature of about 1380 C., the glass can be poured and processed to the desired dimensions as, for example, ribbons. In large-volume, continuous assemblies, the temperatures can be lowered, according to experience, by at least approximately 100 K.

(2) Ribbons are obtained by pouring the glass over two rollers. They can be better ground to powder, a precursor for sintering, than shards.

(3) TABLE-US-00006 TABLE 1 Melt example for 100 kg of calculated glass (according to Example 6) Oxide wt % Raw material Weighed amount (g) SiO.sub.2 39.9 SiO.sub.2 39880.35 Al.sub.2O.sub.3 5.0 Al(OH).sub.3 7669.3 Na.sub.2O 10.0 Na.sub.2CO.sub.3 17099.59 ZnO 8.0 ZnO 7976.07 ZrO.sub.2 5.0 ZrO.sub.2 4985.04 BaO 25.9 BaCO.sub.3 33621.56 1.0 Ba(NO.sub.3).sub.2 1688.70 La.sub.2O.sub.3 5.0 La.sub.2O.sub.3 5030.32 As.sub.2O.sub.3 0.3 As.sub.2O.sub.3 299.10 Sum 100.1 118250.04

(4) The properties of the glass thus obtained are presented in the following table as Example 6.

(5) TABLE-US-00007 TABLE 2 Exemplary embodiments of the glass matrix for the conversion material Example Oxides 2 3 4 5 6 SiO.sub.2 5.3 5.4 5.6 2.8 40 B.sub.2O.sub.3 18.5 19.6 18.1 32.1 Al.sub.2O.sub.3 23.5 5.0 Na.sub.2O 10.0 PbO ZnO 22.1 23.5 4.9 8.0 BaO 2.1 27 TiO.sub.2 2.7 4.2 8.8 ZrO.sub.2 2.9 3.0 6.0 5.0 La.sub.2O.sub.3 35.5 36.8 42.3 5.0 Nb.sub.2O.sub.5 7.4 7.9 12.3 WO.sub.3 5.1 Y.sub.2O.sub.3 41.6 n.sub.d 1.834 1.834 1.901 1.6641 1.6001 CTE.sub.(20.300 C.) 6.9 6.9 7.2 6.97 10.8 [10.sup.6/K] Tg [ C.] 585 590 645 684 541 T (h = 10.sup.7.6 dPas) 673 677 735 742 [ C.] T (h = 10.sup.4 dPas) 786 852 983 [ C.]

Preferred Exemplary Embodiments of the Method of Production of the Conversion Material

(6) The examples described below both of the first group and of the second group of embodiments in accordance with the invention are subject to essentially the same method of production in each case.

(7) Powders of the starting glasses, ground to a grain size having a distribution of d10>=0.7 m, d50>=3 m, and d90<=150 m, are weighed with a luminophorefor example, Ce:YAG having a grain size with a mean diameter d50 between 1 m and 50 m, especially preferably between 1 m and 20 m, most preferably between 1 m and 15 m, based on weight percentand blended in a mixing assemblyfor example, a Turbula tumbling mixer (model T2C/Willi A. Bachofen company/Basel) or Speedmix (model DAC 150 FVZ/Hauschildt Engineering)for 1 to 120 min, preferably 1 to 5 min (Speedmix) or 15 to 120 min (Turbula), most preferably 1 to 3 min (Speedmix) or 60 to 120 min (Turbula).

(8) Here, the d50.sup.2 or else median value is the value that gives a grain size at which 50% of the particles are finer and 50% are coarser that this given value. .sup.2[Translator's Note] D50 in the original

(9) There also exist nanoscale phosphors, that is, luminophores with outer dimensions in the range of several nanometers, in particular of less than 100 to 200 nm, that can also be used.

(10) The powder mixture or else the pure glass powder is subsequently taken in portions in such a way that a powder body having a diameter of approximately 10 mm, preferably 5 mm, most preferably less than 5 mm, but at least 1 mm, and a height of approximately 3 mm or 1 mm or 0.5 to 0.1 mm can be prepared.

(11) The bulk is deposited on a thermally stable substrate in, for example, a tube- or ring-shaped element that delimits the bulk and is compacted manually and/or fed uniaxially (for example, press of the Paul Weber company; Model PW40) and/or cold-isostatically (press of the Paul Weber company; Model KIP500E) to a pressing process, which can be optimally designed by addition of convention processing auxiliaries. The pressure range for the uniaxial pressing lies at 100 to 5000 bar, preferably 500 to 2500 bar. This takes place in such a manner that, subsequently, the outer delimitation can be removed.

(12) Afterwards, the annealing of the samples takes place at temperature and time regimens (heating rates and dwell times) that are appropriate for the matrix glasses in terms of their softening temperature. Depending on the slope of the viscosity curve of the glass and without general restriction, the target temperatures T of the annealing lie in the range between the EW (softening temperature) and Va (processing temperature), usually in a regimen of EW+150 K, or such that the viscosity of the employed glass lies in the range between h=10.sup.14 dPas and h=10.sup.6 dPas, preferably between h=10.sup.13.5 dPas and h=10.sup.7 dPas, especially preferably between h=10.sup.10 dPas and h=10.sup.7 dPas.

(13) The heating takes place such that it is possible to assume an equilibrated temperature level in the oven and for the bulk or, as the case may be, several bulks.

(14) In particular, the time regimen to be chosen in this case depends typically on the type, size, and design (also the control) of the annealing assembly. In the present oven (Nabertherm model N70/H; Naber C16 control and Eurotherm model 2604), heating rates of from 1 K/min to 30 K/min, preferably 1 K/min to 20 K/min, most preferably 1 K/min to 10 K/min, to the target temperature and dwell times before cooling with oven characteristic curve of 0 to 60 min, preferably 0 to 30, most preferably 10 to 30 min, have proven useful.

(15) After the annealing or annealings, the composite bodies thus created, comprising glass matrix and at least one luminophore, are post-processed, with grinding and/or polishing agents of grain size<1 m (single sided) being used, so that, as a result, surfaces that are raw on both sides or on one side or are polished are present.

(16) The measurement of the optical data for reflection and transmission took place in a conventional spectrometer (for example, Perkin Elmer Lambda 9 or 900), with sample in front of (transmission) or in back of (reflection) an integration sphere, in the wavelength region from 250 to 2500 nm, at least, however, in the region from 300 to 800 nm, in order to determine the aforementioned parameters. The determination of the parameters T.sub.half and T.sub.forward also takes place by means of the integration sphere. For further details, reference is made to the discussions in regard to FIG. 1.

(17) The internal conversion quantum yield of the luminophores embedded in the glass matrix was reduced in relation to the internal conversion quantum yield of the non-embedded luminophores by not more than 20%, preferably by not more than 10%, and most preferably by not more than 5%. The internal conversion quantum yield was measured in each case by means of the decay time of excited optical transitions in the luminophores.

(18) TABLE-US-00008 TABLE 3 Example A B C D E F G H Glass type/ Ex. 2 Ex. 2 Ex. 2 Ex. 2 Ex. 3 Ex. 3 Ex. 4 Ex. 6 Fraction wt % 100 98 92.5 85 95 90 90 90 Luminophore 1/ 0 2 5 15 5 10 10 10 Fraction wt % Luminophore 2/ 0 0 2.5 0 0 0 0 0 Fraction wt % Temperature/ C. 700 700 700 700 650 650 743 770 Ramp/K/min 1 1 1 1 15 15 1 1 Dwell time/min 0 0 10 5 45 60 0 5 Thickness undoped/mm 1.5 1.5 1.5 1.5 0.5 0.5 1.5 1.5 Reflection + Transmission 82 + 10 = 82 + 11 = 81 + 9 = 83 + 11 = 89 + 5 = 88 + 7 = 75 + 10 = 80 + 7 = undoped/%; 92 93 90 94 94 95 85 87 for Vis (380-780 nm) incl. PL 404 . . . 460 nm Intrinsic color undoped None None None None None None None None Thickness doped/mm 0.5 0.5 0.2 0.5 0.3/0.5 0.5 0.5 Reflection doped 29% 11% 15% 21% 2 22 17 At PL 460 nm Example 9%/11% Reflection + Transmission 79 + 11 = 78 + 10 = 80 + 14 = 81 + 8 = 73 + 19 = 70 + 11 = 73 + 11 = doped/%; 90 88 94 89 92/ 81 84 Thickness/mm 78 + 10 = for Vis (380-780 nm) 88 excluding PL
Glasses and Glass Families of a Second Group

(19) The following described glasses and glass families of a second preferred group of exemplary embodiments fulfill the requirements in accordance with the invention as well, but have a refractive index that is less than 1.6.

(20) The refractive index of these glasses lies preferably at 1.43 to 1.6 and most preferably at 1.45 to 1.49. As a result, these glasses are matched relatively well to the refractive index of the light sources/units of surrounding polymers (epoxides or silicones, including polymer with n.sub.d between 1.3 and 1.6).

(21) Furthermore, the difference from the refractive index of air, which is, ultimately, the medium surrounding the entire light source system, is markedly reduced.

(22) This matching is important in indirect contact of converter material to semiconductor element and further surrounding (components) elements in order to out-couple efficiently exciting light from the converter (for example, the light of a blue LED), which passes through the converter, as well as light generated in the converter. Here, indirect contact is understood to mean an arrangement without direct mechanical contact; this means, in particular, that the evanescent fields of the disseminating light, which surround the respective materials, do not measurably overlap at all or essentially not at all.

(23) Preferable glasses of this group comprise, for example, zinc phosphates, borosilicates, aluminum borosilicates, and alkaline-earth silicates.

(24) Sample glasses are: BF33/BF40 (SCHOTT AG), Pyrex (Corning) 8250 (SCHOTT AG) AF32 (SCHOTT AG), AF37 (SCHOTT AG), AF45 (SCHOTT AG), 1737 (Corning), Eagle 2000 (Corning), Eagle XG (Corning) N-SK 57 (SCHOTT AG) D263 (SCHOTT AG) Optical glasses K-PBK40 (Sumita), K-CSK120 (Sumita), P-SK5 (Hikari), K-PSK50 (Sumita), D-K9L (GDGM), D-ZK2(GDGM), D-ZK3 (GDGM)

(25) Advantageously provided with the present invention is, among other things, a glass matrix for conversion materials, with which, particularly on account of ecological considerations, without the use of Tl.sub.2O, TeO.sub.2, and As.sub.2O.sub.3 and preferably also without the component Bi.sub.2O.sub.2, desired and advantageous optical properties (n.sub.d/v.sub.d) are made possible at simultaneously low processing temperatures.

(26) These glasses have no haze, crystallization, and intrinsic coloration as matrix glass and, furthermore, are sinterable without intrinsic coloration. In this case, these glasses are only slightly chemically reactive toward the luminophores used.

(27) Furthermore, these glasses are easy to melt and to process and have an adequate demixing and crystallization stability, which makes possible a manufacture of glasses in continuously operating assemblies.

(28) In particular, an arsenic-free and preferably Bi.sub.2O.sub.3-free glass with a refractive index glass n.sub.d of n.sub.d<1.6 provided, which comprises the following components (in wt % based on oxide).

(29) The following table comprises Example 1 of the second group:

(30) TABLE-US-00009 P2O5 44-55 B2O3 0-8 Al2O3 0-5 ZnO 22-32 La2O3 0.5-5 BaO 4-13 Na.sub.2O 5-15 K.sub.2O 0-8 MgO 0-5 CaO 0-5 Sum of alkali oxides <=15 Sum of alkaline- <=8 earth oxides

(31) Preferably

(32) TABLE-US-00010 P.sub.2O.sub.5 46-53 B.sub.2O.sub.3 0-5 Al.sub.2O.sub.3 0-3 ZnO 24-31 La.sub.2O.sub.3 0.5-4 BaO 4-11 Na.sub.2O 6-13 K.sub.2O 0-6 MgO 0-4 CaO 0-4 Sum of alkali oxides <=13 Sum of alkaline- <=5 earth oxides Refining agent <=2

(33) The following table comprises Example 2 of the second group:

(34) TABLE-US-00011 SiO2 40-44 B2O3 14-16 Al2O3 3-6 ZnO 2-4.5 TiO2 0.1-0.5 BaO 23-27 SrO 0.1-1 Li.sub.2O 5.5-<7 Na.sub.2O 2-4 K.sub.2O 0-4

(35) Preferably

(36) TABLE-US-00012 SiO.sub.2 41-43 B.sub.2O.sub.3 14-16 Al.sub.2O.sub.3 3.5-6 ZnO 2.5-4 TiO.sub.2 0.1-0.5 BaO 23-27 SrO 0.3-1 Li.sub.2O 5.5-6.5 Na.sub.2O 2-4 K.sub.2O 0-6

(37) The following table comprises Example 3 of the second group:

(38) TABLE-US-00013 SiO.sub.2 >58-65 B.sub.2O.sub.3 >6-10.5 Al.sub.2O.sub.3 >14-25 ZnO 0-<2 BaO >3-5 MgO 0-<3 CaO <=9 MgO + CaO + BaO >=8 ZrO.sub.2 0-2 TiO.sub.2 0-2 ZrO.sub.2 + TiO.sub.2 0-2 As.sub.2O.sub.3 0-1.5 Sb.sub.2O.sub.3 0-1.5 CeO.sub.2 0-1.5 Cl.sup. 0-1.5 F.sup. 0-1.5 SO.sub.4.sup.2 0-1.5 As.sub.2O.sub.3 + Sb.sub.2O.sub.3 + SnO.sub.2 + <1.5 CeO.sub.2 + Cl.sup. + F.sup. + SO.sub.4.sup.2

(39) Preferably

(40) TABLE-US-00014 SiO.sub.2 >58-65 B.sub.2O.sub.3 >8-10.5 Al.sub.2O.sub.3 >18-20.5 ZnO 0.1-<2 BaO >3-4 MgO 0-<3 CaO -<=9 MgO + CaO + BaO >=8 ZrO.sub.2 0-2 TiO.sub.2 0-2 ZrO.sub.2 + TiO.sub.2 0-2 As.sub.2O.sub.3 0-1.5 Sb.sub.2O.sub.3 0-1.5 CeO.sub.2 0-1.5 Cl.sup. 0-1.5 F.sup. 0-1.5 SO.sub.4.sup.2 0-1.5 As.sub.2O.sub.3 + Sb.sub.2O.sub.3 + SnO.sub.2 + <1.5 CeO.sub.2 + Cl.sup. + F.sup. + SO.sub.4.sup.2

(41) The following table comprises Example 5 of the second group:

(42) TABLE-US-00015 SiO.sub.2 55-79 B.sub.2O.sub.3 3-25 Al.sub.2O.sub.3 0-10 Li.sub.2O 0-10 Na.sub.2O 0-10 K.sub.2O 0-10 Li.sub.2O + Na.sub.2O + K.sub.2O 0.5-16 MgO 0-2 CaO 0-3 SrO 0-3 BaO 0-3 ZnO 0-3 MgO + CaO + SrO + BaO + ZnO 0-10 ZrO.sub.2 0-3 CeO.sub.2 0-1 WO.sub.3 0-1 Refining agent 0-2

(43) The following table comprises Example 6 of the second group:

(44) TABLE-US-00016 SiO.sub.2 65-82 B.sub.2O.sub.3 5-13 Al.sub.2O.sub.3 2-8 ZrO.sub.2 0-2 Li.sub.2O + Na.sub.2O + K.sub.2O 3-10 MgO + CaO + SrO + BaO + ZnO 0-7 Refining agent 0-2

(45) The glass in accordance with the invention is preferably also free of coloring and/or optically active, as well a laser-active, components.

(46) In particular, the glass in accordance with the invention is preferably also free of components that are sensitive to oxidation, such as, for example, Ag.sub.2O or Bi.sub.2O.sub.3, and/or free of toxic components or components hazardous to health, such as, for example, the oxides of Tl, Te, Be, and As. In any case, the glass is preferably free of arsenic.

(47) In accordance with an embodiment of the present invention, the glass is also preferably free of other components not mentioned in the claims; that is, in accordance with such an additional embodiment, the glass essentially comprises the mentioned components.

(48) The expression essentially comprises means in this case that other components are present at most as impurities, but are not added intentionally to the glass composition as individual components.

(49) The glass in accordance with the invention can contain conventional refining agents in small amounts. Preferably, the sum of the added refining agents is at most 2.0 wt %, more preferably at most 1.0 wt %. As refining agent, the glass in accordance with the invention can contain at least one of the following components (in wt %, additively to the remaining glass composition):

(50) TABLE-US-00017 Sb.sub.2O.sub.3 0-1 And/or As.sub.2O.sub.3 0-1 And/or SnO 0-1 And/or SO.sub.4.sup.2 0-1 And/or Cl.sup. 0-1 And/or F.sup. 0-1

(51) Fluorine and fluorine-containing compounds also tend to vaporize during the melting and fusing operation and during the sintering process and, as a result, make more difficult a precise adjustment of the glass composition or, after sintering, the glass matrix. The glass in accordance with the invention is therefore preferably also free of fluorine.

(52) The glasses described in the examples were produced using different process parameters, which are associated with the physical properties of the glasses.

Production Example 2

(53) The raw materials for the oxides are weighed, one or more refining agents, such as, for example, Sb.sub.2O.sub.3, are added, and subsequently well mixed. The glass quantity is fused at approximately 1320 C. in a discontinuous melting assembly and afterwards refined (1370 C.) and homogenized. At a pouring temperature of about 1320 C., the glass can be poured and processed to the desired dimensions as, for example ribbons. In large-volume, continuous assemblies, the temperatures can be lowered, according to experience, by at least approximately 100 K.

(54) Ribbons are obtained by pouring the glass over two rollers. They can be better ground to powder, a precursor for sintering, than shards.

(55) TABLE-US-00018 TABLE 4 Melt example for 100 kg of calculated glass (in accordance with Example 8) Weighed Oxide wt % Raw material quantity (g) SiO.sub.2 42.85 SiO.sub.2 42913.69 B.sub.2O.sub.3 14.9 B.sub.2O.sub.3 15128.18 Al.sub.2O.sub.3 4.15 AlO(OH) 5348.39 Li.sub.2O 6.27 LiNO.sub.3 15598.33 Na.sub.2O 2.7 Na.sub.2CO.sub.3 4613.41 ZnO 3.4 ZnO 3400.29 SrO 0.72 Sr(NO.sub.3).sub.2 1484.69 BaO 24.5 BaCO.sub.3 31779.59 TiO.sub.2 0.2 TiO.sub.2 201.51 Sb.sub.2O.sub.3 0.30 Sb.sub.2O.sub.3 301.14 Sum 100.20 120769.21

(56) The properties of the glass thus obtained are presented in the following Table 5 as Example 8.

(57) TABLE-US-00019 TABLE 5 Oxide Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 SiO.sub.2 42.9 61.4 49.5 68.2 80.6 B.sub.2O.sub.3 14.9 8.2 14.2 19 12.7 P.sub.2O.sub.5 49.8 Al.sub.2O.sub.3 1.9 4.2 16.0 11.4 2.7 2.4 Li.sub.2O 6.3 0.7 Na.sub.2O 9.8 2.7 0.7 3.5 K.sub.2O 7.9 0.6 ZnO 27.2 3.4 0.6 MgO 2.8 CaO 2.0 7.9 SrO 0.7 BaO 7.3 24.5 3.5 24.1 TiO.sub.2 0.2 La.sub.2O.sub.3 2.0 n.sub.d 1.573 1.587 1.523 1.49 1.47 a.sub.(20.300 C.) 8.9 3.75 4.5 5.0 3.3 [10.sup.6/K] Tg [ C.] 373 493 709 711 488 525 T 593 883 942 715 820 (h = 10.sup.7.6 dPas) [ C.] T (h = 551 751 1273 1263 1060 1260 10.sup.4 dPas) [ C.]

Further Exemplary Embodiments of the Production of the Conversion Material

(58) The examples described below in regard to the glasses of the second group are subject to essentially the same method of production in each case (see for this the glasses of the first group). For further or lacking details, reference is made to the preceding description.

(59) Powders of the starting glasses, ground to a grain size having the distribution of d10>=0.7 m, d50>=3 m, and d90<=150 m, are weighed with a luminophorefor example, Ce:YAG having a grain size with a mean diameter d50 between 1 m and 50 m, especially preferably between 1 m and 20 m, most preferably between 1 m and 15 m, based on weight percentand blended in a mixing assemblyfor example, a Turbula tumbling mixer (model T2C/Willi A. Bachofen company/Basel) or Speedmix (model DAC 150 FVZ/Hauschildt Engineering)for 1 to 120 min, preferably 1 to 5 min (Speedmix) or 15 to 120 min (Turbula), most preferably 1 to 3 min (Speedmix) or 60 to 120 min (Turbula).

(60) The powder mixture or else the pure glass powder is subsequently taken in portions in such a way that a powder body having a diameter of approximately 12 mm/8 mm/<5 mm and a height of approximately 3 mm/2/1 can be prepared.

(61) The bulk is deposited on a thermally stable substrate in, for example, a tube- or ring-shaped element that delimits the bulk and is compacted manually and/or fed uniaxially and/or cold-isostatically to a pressing process, which can be optimally designed by addition of convention processing auxiliaries. This takes place in such a manner that, subsequently, the outer delimitation can be removed.

(62) Afterwards, the annealing of the samples takes place at temperature and time regimens (heating rates and dwell times) that are appropriate for the matrix glasses in terms of their softening temperature. Depending on the slope of the viscosity curve of the glass and without general restriction, the target temperatures T of the annealing lie in the range between the EW, the softening temperature, and Va, the processing temperature, of the matrix glass usually in a regimen of EW+150 K.

(63) The heating takes place such that it is possible to assume an equilibrated temperature level in the oven and for the bulk or, as the case may be, several bulks.

(64) In particular, the time regimen to be chosen in this case depends typically on the type, size, and design (also the control) of the annealing assembly. In the present oven (Nabertherm model N70/H; Naber C16 control and Eurotherm model 2604), heating rates of from 1 K/min to 30 K/min, preferably 1 K/min to 20 K/min, most preferably 1 K/min to 10 K/min, to the target temperature and dwell times before cooling with oven characteristic curve of 0 to 60 min, preferably 0 to 30, most preferably 10 to 30 min, have proven useful.

(65) After the annealing or annealings, the composite bodies thus created, comprising glass matrix and at least one luminophore, are post-processed, with grinding and/or polishing agents of grain size<400 m (two-sided) as well as, depending on the case, for example, diamond polishing agents of grain size up to <1 m (single sided) being used, so that, as a result, surfaces that are raw on both sides or on one side or are polished are present. The measurement of the optical data for reflection and transmission takes place in a conventional spectrometer, with sample in front or at the input (transmission) or in back or behind at the output (reflection) of an integration sphere, in the wavelength region from 250 to 2500 nm, at least, however, in the region from 300 to 800 nm, in order to determine the aforementioned values.

(66) TABLE-US-00020 TABLE 6 Example I J K L M N O P Glass type/ Ex. 7 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 11 Ex. 12 Ex. 12 Fraction wt % 100 98 95 85 95 90 100 90 Luminophore 1/ 0 2 5 15 5 10 10 10 Fraction wt % Luminophore 2/ 0 0 0 0 0 0 0 0 Fraction wt % Temperature/ C. 700 700 700 700 650 650 743 770 Ramp/K/min 1 1 1 1 15 15 1 1 Dwell tme/min 0 0 10 5 45 60 0 5 Thickness undoped/mm 1.5 1.5 1.5 1.5 0.8 0.9 1.5 1.5 Reflection + Transmission 72 + 9 = 78 + 11 = 81 + 9 = 83 + 11 = 63 + 24 = 63 + 24 = 87 + 9 = 87 + 9 = undoped/%; 81 89 90 94 87 87 96 96 for Vis (380-780 nm) incl. PL 404 . . . 460 nm Intrinsic color None None None None None None None None undoped Thickness doped/mm nn nn Nn Nn Nn 0.3 Nn 0.3 Reflection doped 24 16 At PL 460 nm Reflection + Transmission 58 + 23 = 78 + 14 = doped/%; 81 92 Thickness/mm for Vis (380-780 nm) excluding PL

(67) The present invention will be explained below on the basis of FIGS. 1 to 5.

(68) First of all, FIG. 1 illustrates the measurement of the parameter T.sub.half (top) and T.sub.forward (bottom) on a sample 2 of a matrix glass, which has been ground to a powder and sintered, by means of an integration sphere 3.

(69) The integration sphere 3 has a diameter of 60 mm and a sphere aperture with a diameter of about 12 to 15 mm. A rectangular diaphragm (cross section: 612 mm.sup.2) is positioned before the sphere 3 as an additional component. A light source 1, which emits essentially only parallel light in relation to the beam axis as measuring beam, is positioned at a spacing of approximately 50 cm from the integration sphere 3. The measuring beam has a cross section of 410 mm.sup.2. A sample 2 to be investigated is arranged at various distances between the integration sphere 3 and the light source 1. The sample 2 has an outer diameter greater than about 12 mm or greater than about 12 mm times greater than 12 mm (for a rectangular sample 2). The thickness of the sample lies at about 1 mm (0.05 mm). A spectrometer 4 with a photodetector for detecting the light registered by the integration sphere 3 is arranged in the beam direction directly behind the integration sphere 3.

(70) During the measurement of T.sub.half, the sample 2 is positioned at a distance of less than or equal to about 3 mm from the integration sphere 3 in order to register both the directly transmitted portion of the light and the portions scattered in the sample 2 emitted from the parallel light source 1.

(71) By contrast, during the measurement of T.sub.forward, the sample 2 is positioned at a distance from the integration sphere 3. The distance is about 43 cm. As a result, essentially only the directly transmitted portion or the portion transmitted in the forward direction is registered.

(72) This kind of measurement makes possible a classification of the undoped samples 2 investigated here and/or, as the case may be, the doped samples 2 in regard to their transmission and/or scattering behavior. The classification of the samples 2 or the characterization of the samples 2 can be expressed by the quotient T.sub.half:T.sub.forward.

(73) For an ideally optically transparent, non-scattering sample 2, such that the light beams would run exclusively in the beam direction, a value of 1 or nearly 1 would be obtained for the ratio T.sub.half:T.sub.forward. By contrast, a sample with a high scattering behavior would lead to very large values of T.sub.half:T.sub.forward.

(74) During the measurement of the transmission, the sample 2 is thus positioned before and, in particular, at the input of the integration sphere 3. In contrast to this, during the measurement of reflection, the sample 2 is positioned behind and, in particular, at the output of the integration sphere 3. The detector of the spectrometer 4 is located at any point on the circumference of the integration sphere 3.

(75) Illustrated in FIGS. 2 to 5 are several results, which were determined for the aforementioned Glass Example 2) see Tables 2 and 3) and the aforementioned Glass Example 11 (see Tables 2 and 3). Shown in FIG. 2 are the grain size distributions in accordance with the invention, while FIGS. 3 to 5 show the associated results for T.sub.half:T.sub.forward.

(76) These optical characteristic sizes can be measured, for example, by means of a commercially available spectrometer (for example, Perkin Elmer Lambda 9 or 900).

(77) Illustrated to this end in FIG. 2 are the cumulative values of the grain size distribution as a function of the diameter of the grains (measurement, for example, with a Cilas Model 1064 grain size measuring instrument).

(78) Specifically illustrated are three different grain size distributions (KGV1, KGV2, and KGV3) [KGV=grain size distribution] for the two aforementioned Glass Examples 2 and 11. The numerical results, belonging to FIG. 2, for the grain sizes at d10, d50, and d90 are summarized in Table 7. Shown in the first column are the designations used in Table 8.

(79) TABLE-US-00021 TABLE 7 Diameter Diameter Diameter d10 D50 d90 (10.00%) (50.00%) (90.00%) II Glass Ex. 2 KGV 1 0.8 5.4 16.4 I Glass Ex. 2 KGV 2 1.1 11.7 33.3 Glass Ex. 2 KGV 3 1.8 18.7 56.5 V Glass Ex. 11 KGV 3 23.6 55.8 94.9 Glass Ex. 11 KGV 2 1.5 10.3 27.2 IV Glass Ex. 11 KGV 1 1.2 5.0 16.1

(80) The illustration is explained on the basis of Example 11 KGV3 (line V): 10% of the grains or particles have a diameter of less than about 23.6 m, 50% of the particles have a diameter of less than about 55.8 m, and 90% of the particles have a diameter of less than 94.9 m. It can be seen that the particles for 11 KGV3 have the largest diameters.

(81) The process parameters used for the Glass Examples 2 KGV1 (II), 2 KGV2 (I), 11 KGV1 (IV), 11 KGV3 (V) are summarized in Table 8. In this case, two different methods are given for the Glass Example 2 KGV1: (II) with double annealing, that is, sintering and subsequent thermal treatment, as well as, for example, a second sintering, and (III) with single annealing or sintering. The parameter (t@T/) describes the dwell time at T in minutes.

(82) TABLE-US-00022 TABLE 8 Glass 2 Glass 2 Glass 2 Glass 11 Glass 11 KGV 2 KGV 1 KGV 1 KGV 1 KGV 3 Example I II III IV V Thickness/mm 1.00 0.99 1.00 1.02 1.01 T.sub.half:T.sub.forward 5.2; 52; 24.2; 11.6; 1.17; (400 nm; 750 nm) 2.2 52 4.8 3.2 1.17 Annealing 1 700, 0 700, 0 700, 0 760, 60 760, 60 T/ C., t@T/ Annealing 2 650, 650, 0, 0, 0 650, 650, 500, T/ C., P/bar, 500, 30 500, 30 500, 30 30 t@T/

(83) FIG. 3 shows the transmission T.sub.half and T.sub.forward as a function of the light wavelength for the aforementioned Examples I to III. FIG. 4 shows the transmission T.sub.half and T.sub.forward as a function of the light wavelength for the Examples IV and V. If the separation of the curves T.sub.half and T.sub.forward, that is, the difference of the ordinate values, is relatively small, [so that].sup.3 Sample 2 has a small scatter. If, by contrast, the curves have a relatively large separation from each other, Sample 2 has a large scatter. The characterization of Samples 2 takes place by way of the quotient T.sub.half:T.sub.forward. .sup.3 [Translator's Note] sic

(84) Illustrated to this end, finally, in FIG. 5 is the ratio of T.sub.half over T.sub.forward. For all shown Examples I to V, the ratios achieved lie in the range that is advantageous in accordance with the invention. For Example V, for which the particles have the largest diameter, a T.sub.half:T.sub.forward value of even nearly 1 is obtained. The sintered glass body has a small scatter. Whether the scatter within the sample is undesired or even desired is decided on the basis of the converter system, that is, containing embedded luminophore, or on the basis of the overall conversion-LED system on the basis of the requirements placed on the system. For example, in a system in which the refractive indices lie close to one another, a larger scatter may be required. In particular, it is also crucial that the criterion for the sum of transmission and reflection is fulfilled.

(85) The matrix glass described above can be used for creating a light source, in particular a white or colored light source, with the matrix glass containing the luminophore or luminophores corresponding to a conversion material that preferably comprises the features of the conversion material defined in one of claims 1 to 21 and preferably is produced by means of a method having the features of one of claims 22 to 28.

(86) In a preferred embodiment, the light source comprises a primary light source, in particular a semiconductor light source, which emits light with wavelengths in the region from 225 nm to 520 nm, preferably from 350 nm to 480 nm, most preferably with wavelengths in the region from 400 nm to 480 nm.

(87) In an alternative embodiment, the primary light source comprises an LED, which emits light with a wavelength in the region from 400 nm to 480 nm, preferably 420 nm to 480 nm.

(88) In another preferred embodiment, the primary light source comprises a UV LED, which emits light with a wavelength in the region 235 nm to 400 nm, preferably 350 nm to 400 nm.

(89) In yet another embodiment, the primary light source comprises the primary light source of a semiconductor laser diode, which emits light with a wavelength in the region from 400 nm to 480 nm.

(90) The light source can have one or more, in particular also several different, primary light sources.

(91) Further descriptions of these light sources as well as their spatial arrangement and properties may be found in the application titled Optik-Konverter-System fr (W) LEDs [Optical Converter System for (W) LEDs] with the internal file reference 08SGL0020DEP or P 3156 and in the application titled Gehuse fr LEDs mit holier Leistung [Housing for LEDs with High Power] with the internal file reference 08SGL0060DEP or P 3063 of the same applicant, which were filed on the same day as this application and which are also in full scope a part of the content of this application by way of reference.

(92) With several primary light sources and several luminophores, it is possible to create a light source with which it is possible to emit light at the following color coordinates in (X, Y) color space, in particular by selecting the luminophore or luminophores as well as by adjusting the concentration of the luminophores and/or the thickness of the converter material: A=(0.16,0.02) B=(0.05,0.30) C=(0.02,0.76) D=(0.21,0.76) E=(0.72,0.28).

(93) In this way, a color space within the traverse ABCDE is defined or enclosed, within which light of all color coordinates can essentially be emitted from the light source.

(94) The adjustment of the color coordinates within the aforementioned traverse as well as the traverse discussed below can be undertaken at one time and in a definitively defined manner by establishing the ratio and concentration of the respective luminophores as well as, in the case of several light sources, the intensity of emission of the respective light sources.

(95) Furthermore, in the case of several primary light sources, it is additionally possible, within a certain scope, to change the color coordinate by changing the intensity of the emission of one or more primary light sources.

(96) In another embodiment of the light source, it is possible to emit light at the following color coordinates in (X, Y) color space, in particular by selecting the primary light source, by selecting the luminophore or luminophores as well as by adjusting the concentration of the luminophores and/or the thickness of the converter material: F=(0.28,0.24) G=(0.37,0.35) H=(0.37,0.40) I=(0.24,0.28).

(97) In yet another embodiment of the light source, it is possible to emit light at the following color coordinates in (X, Y) color space, in particular by selecting the primary light source, by selecting the luminophore or luminophores as well as by adjusting the concentration of the luminophores and/or the thickness of the converter material: J=(0.37,0.35) K=(0.37,0.42) L=(0.50,0.45) M=(0.50,0.38).

(98) In yet another embodiment of the light source, it is possible to emit light at the following color coordinates in (X, Y) color space, in particular by selecting the primary light source, by selecting the luminophore or luminophores as well as by adjusting the concentration of the luminophores and/or the thickness of the converter material: N=(0.21,0.76) O=(0.66,0.34) P=(0.60,0.34) Q=(0.15,0.76).

(99) In this way, it is possible to create, in particular, saturated colors green-yellow-orange (amber) NOPQ and, moreover, it is possible, to create all saturated colors in the spectral region from 535 nm to 610 nm by selection of the primary light source or light sources, which, otherwise, would have only low efficiencies with pure LEDs.

(100) For understanding the following patent claims, it is noted that, for a first embodiment of the invention, the term in the spectral region in which the primary light source emits light allows comprises only the spectral region of a single primary light source. This single primary light source is, in this case, one of the primary light sources mentioned in the preceding description or in the following claims.

(101) In further embodiments in accordance with the invention, the term in the spectral region in which the primary light source emits light comprises the spectral region of more than only a single primary light source. In this case, two or more than two primary light sources with various emission spectra may be used, in particular in order to span a larger color spaces as well. However, these two or more primary light sources also each comprise only the primary light sources mentioned only in the preceding description or in the following claims.

(102) It is obvious to the skilled practitioner that the described embodiments are to be understood as examples. The invention is not limited to these, but rather can be varied in diverse ways without departing from the spirit of the invention. The features of the individual embodiments and the features mentioned in the general part of the description can each be combined both among each other and with each other.