Lighting unit with at least one LED as light source

Technical field

0001The invention is based on a lighting unit with at least one LED as a light source according to the preamble of claim 1. It is in particular a luminescence conversion LED emitting in the visible or white, based on an LED emitting primarily in the near UV or short-wave blue.

State of the art

0002LEDs that emit white light are currently predominantly made by combining a Ga (In) N LED emitting in the blue at around 460 nm and a yellow emitting YAG: Ce³⁺- fluorescent generated (<patcit id="pcit0001" dnum="US5998925A"><text>US 5,998,925</text></patcit> and <patcit id="pcit0002" dnum="EP862794A"><text>EP 862 794</text></patcit>). However, these white light LEDs can only be used to a limited extent for general lighting purposes because of their poor color rendering due to the lack of color components (especially the red component). Instead, attempts are also being made to combine primarily blue-emitting LEDs with several phosphors in order to improve the color rendering, see<patcit id="pcit0003" dnum="WO0033389A"><text>WO 00/33389</text></patcit> and <patcit id="pcit0004" dnum="WO0033390A"><text>WO 00/33390</text></patcit>.

0003Basically, it is also known to realize white-emitting LEDs with so-called organic LEDs or by interconnecting monochrome LEDs with a corresponding color mixture. Usually a UV LED (emission maximum between 300 and 370 nm) is used, which is converted into white light by means of several phosphors, usually three, which emit in the red, green and blue spectral range (RGB mixture) (<patcit id="pcit0005" dnum="WO9839805A"><text>WO 98 39 805</text></patcit>, <patcit id="pcit0006" dnum="WO9839807A"><text>WO 98 39 807</text></patcit> and <patcit id="pcit0007" dnum="WO9748138A"><text>WO 97 48 138</text></patcit>). As the blue component, BaMgAl is an inorganic phosphor₁₀O₁₇: Eu^{z +} or ZnS: Ag⁺ known; as a blue-green component ZnS: Cu⁺, or (Zn, Cd) S: Cu⁺, or ZnS: (Al, Cu)⁺; as the red component Y₂O₂S: Eu²⁺. A number of organic phosphors are also recommended.

0004For white emitting sources of high light quality with small dimensions or as backlighting from e.g. B. LCDs are less suitable for fluorescent lamps and incandescent lamps. OLEDs are more suitable for this, but the UV resistance of organic phosphors is poorer than that of inorganic phosphors. In addition, the manufacturing costs are higher. Blue LEDs with the phosphor YAG: Ce³⁺ (and grenades derived from them) are also suitable in principle, but there are disadvantages in the color locus setting: the color locus can only be selected in a limited manner in such a way that white light is produced which gives good color rendering, since the white color impression is primarily due to the mixture of blue emissions of the LED and yellow emission of the phosphor. The disadvantage of fluorescent lamps and UV (O) LEDs is that UV energy is converted into visible light with poor energy efficiency; UV radiation (in fluorescent lamps 254 and 365 nm; in UV LEDs 300 - 370 nm) with a wavelength of e.g. B. 254 nm is converted into light with a wavelength of 450-650 nm. This means an energy loss of 40 to 60% with a theoretical quantum efficiency of 100%.

0005Organic phosphors are generally more difficult to manufacture than inorganic phosphors and, moreover, are generally too unstable to be used in long life light sources (e.g., over 30,000 hours).

0006This prior art has some significant disadvantages with regard to the energy efficiency of the combination of LEDs and phosphors and / or the stability of the phosphors and / or restrictions with regard to the geometric dimensions.

Presentation of the invention

0007It is an object of the present invention to provide a lighting unit with at least one LED as a light source according to the preamble of claim 1, which is characterized by high efficiency.

0008These objects are achieved by the characterizing features of claim 1. Particularly advantageous refinements can be found in the dependent claims.

0009The invention is particularly advantageous in connection with the development of an LED emitting in the visible or white. This LED can be produced by combining an LED emitting in near UV or very short-wave blue light (collectively referred to here as "short-wave") with an emission wavelength between 370 and 430 nm and at least one of the phosphors listed below which emits the radiation of the LED entirely or partially absorbed and even emitted in spectral ranges, whose additive mixture with the light of the LED and / or other dyes gives white light with good color rendering or light with a desired color location. Depending on the application, a single phosphor with the properties according to the invention can suffice. Possibly. it can also be combined with one or more other phosphors according to the invention or phosphors of other classes, for example of the YAG: Ce type. The blue light of the LED is not (or hardly) usable directly, in contrast to the prior art, which uses longer-wave blue (430 to 480 nm), but is only suitable for the primary excitation of the phosphors.

0010A primary radiation source whose emission is much closer to the wavelength at which the phosphors emit can significantly increase energy efficiency. For example, with a source that emits at 400 nm, the energy loss is reduced to only 12 to 39%.

0011The technical problem lies in the development and production of sufficiently efficient phosphors that can be excited in the spectral range between 370 nm and 430 nm and at the same time show suitable emission behavior.

0012In order to implement a colored or white LED, a phosphor according to the invention, possibly in combination with one or more other phosphors, is combined with a binder that is as transparent as possible (<patcit id="pcit0008" dnum="EP862794A"><text>EP 862 794</text></patcit>). The phosphor completely or partially absorbs the light of the UV / blue light-emitting LED and emits it again broadband in other spectral ranges, so that an overall emission with the desired color location arises. So far, there are hardly any phosphors that meet these requirements as well as the phosphors described here. They show a high quantum efficiency (typically 70%) and at the same time a spectral emission that is perceived as bright due to the sensitivity of the eye. The color locus can be set in a wide range. The advantages of these phosphors also include their relatively light, environmentally friendly manufacture, their non-toxicity and their relatively high chemical stability.

0013The invention relates in particular to a lighting unit with at least one LED as light source (light emitting diode), which generates special, specifically desired color tones (for example magenta) or which, for example, generates white light by using a primarily short-wave (i.e. UV to blue in the range 370 to 430 nm ) emitting radiation is converted to white using several phosphors: either by mixing the secondary radiation from a blue and yellow emitting phosphor or in particular by RGB mixing from three phosphors that emit red, green and blue. For particularly high demands on color rendering, more than three phosphors can be combined. For this purpose, one of the phosphors used according to the invention can also be combined with other phosphors already known for this use, such as, for example, SrS: Eu (<patcit id="pcit0009" dnum="WO0033390A"><text>WO 00/33390</text></patcit>) or YAG: Ce (<patcit id="pcit0010" dnum="US5998925A"><text>US 5,998,925</text></patcit>) be combined.

0014A Ga (In, Al) N-LED is particularly suitable as the primary short-wave emitting LED, but also any other way of producing a short-wave LED with a primary emission in the range 370 to 430 nm.

0015The invention extends the spectral emission characteristics of LEDs by using other phosphors and their mixtures beyond the current state of knowledge (see Tables 1 to 3). The selection of the phosphors and mixtures used can be made in such a way that, in addition to true-color white, other mixed colors with broadband emission are also generated. In general, the light emitted by the LED is absorbed by the mixture that contains phosphors. This mixture is either applied directly to the LED or dispersed in a resin or silicone or applied to a transparent disc over one LED or applied to a transparent disc over several LEDs.

0016The inventive step is that the use of LEDs with emission wavelengths between 370 and 430 nm (invisible or barely visible deep blue) and the use of phosphors listed below enables improved spectral adaptation of the LED emission and any color locations adjustable, with a higher energy efficiency than with conventional LEDs.

0017Inorganic phosphors that can be excited in a relatively boring manner are hardly known at present. Surprisingly, however, it has been shown that there are a number of inorganic phosphors which are suitable for being efficiently excited with radiation having a peak emission wavelength of 370-430 nm. Typical half-value widths of the emission are 20 nm to 50 nm. The absorption of the phosphors can be controlled by the selected structural parameters and chemical composition. Such phosphors all have a relatively small band gap (typically around 3 eV) or they have a strong crystal field for the ion, which absorbs the UV / blue light emitted by the LED around 400 nm.

0018Depending on the selected luminescence wavelength of the LED (370-430 nm) and depending on the desired color rendering and / or the desired color location, certain combinations of phosphors can be selected in the phosphor mixture. The most suitable phosphor mixture therefore depends on the chosen target (color rendering, color location, color temperature) and the existing LED emission wavelength.

0019In principle, any phosphor that meets the above-mentioned conditions is suitable for use. Phosphors that emit efficiently and that can be efficiently or at least partially excited in the 370-430 nm range are listed in the following tables. Tab. 1 describes suitable blue phosphors with a peak emission wavelength of 440 to 485 nm, Tab. 2 suitable green phosphors with a peak emission wavelength of 505 to 550 nm and Tab. 3rd suitable red phosphors with a peak emission wavelength of 560 to 670 nm. This makes it possible for the first time to manufacture LEDs with high efficiency, which are based on a short-wave emitting diode that excites several phosphors.<tables id="tabl0001" num="0001"><table frame="none"><title><u style="single">Table 1: Blue-emitting phosphors:</u></title><tgroup cols="2" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52mm" /><colspec colnum="2" colname="col2" colwidth="114mm" /><tbody><row><entry>M₅(PO₄)₃(X): Eu²⁺</entry><entry>with M = at least one of the metals Ba, Ca alone or in combination with Sr (Sr is preferably at most 85%), where X = at least one of the halogens F or Cl;</entry></row><row><entry>M * 3MgSi2O8: Eu2 +</entry><entry>with M = at least one of the metals Ba, Ca, Sr alone or in combination</entry></row><row><entry>Ba₅SiO₄Br₆: Eu²⁺</entry><entry /></row><row><entry>Ba_1.29Al₁₂O_19.29: Eu²⁺</entry><entry /></row><row><entry>YSiO₂N: Ce³⁺</entry><entry /></row><row><entry>(Sr, Ba)₂Al₆O₃₁: Eu²⁺</entry><entry /></row><row><entry>MF₂: Eu²⁺</entry><entry>with M = at least one of the metals Ba, Sr, Ca; Ba's share of M is preferably> 5%, for example Ba = 10%, ie M = Ba_0.10Sr._0.45Approx_0.45.</entry></row><row><entry>Ba_0.57Eu_0.09O_0.34Al_11.11O₁₇: Eu²⁺</entry><entry /></row><row><entry>M ** MgAl10O17: Eu2 +</entry><entry>with M ** = at least one of the metals Eu, Sr alone or in combination with Ba (Ba fraction is preferably at most 75%);</entry></row><row><entry>MLn2S4: Ce³+ with M =</entry><entry>a combination of the metals Ca, Sr; and Ln = at least one of the metals La, Y, Gd.</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="none"><title><u style="single">Table 2: Green (and teal) emitting phosphors</u></title><tgroup cols="2" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="44mm" /><colspec colnum="2" colname="col2" colwidth="122mm" /><tbody><row><entry>SrAl₂O₄: Eu²⁺</entry><entry /></row><row><entry>MB03: ​​(Ce3 +, Rb3 +)</entry><entry>with M = at least one of the metals Sc, Gd, Lu alone or in combination with Y (imsb. is Y content <40%); and the metals Ce and Tb act together as an activator; in particular the proportion of Ce in metal M is in the range 5% ≤ Ce 20 20% and the proportion of Tb in metal is in the range 4% T Tb ≤ 20; Ce portion> Tb portion is preferred;</entry></row><row><entry>M2SiO5: (Ce3 +, Tb3 +)</entry><entry>with M = at least one of the metals Y, Gd, Lu; and the metals Ce and Tb act together as activator (preference is given to proportion Ce> proportion Tb);</entry></row><row><entry>MN⁺2S4: Ak</entry><entry>with M = at least one of the metals Zn, Mg, Ca, Sr, Ba; with N = at least one of the metals Al, Ga, In; and Ak = either a combination of Eu2 +, Mn2 together (preferably fraction Eu> fraction Mn) or a combination of Ce3 +, Tb3 + together (fraction Ce> fraction Tb is preferred);</entry></row><row><entry>SrBaSiO₄: Eu²⁺</entry><entry /></row><row><entry>Ba_0.82Al₁₂O_18.82: Eu²⁺</entry><entry /></row><row><entry>Ba_0.82Al₁₂O_18.82: Eu²⁺, Mn²⁺</entry><entry /></row><row><entry>Y₅(SiO₄)₃N: Ce³⁺;</entry><entry /></row><row><entry>Ca8Mg (SiO4) 4Cl2: Ak2 +</entry><entry>with Ak = Eu2 + alone or together with Mn2 (Eu portion> 2xMn portion is preferred);</entry></row><row><entry>Sr4Al14O25: Eu2 +</entry><entry /></row><row><entry>(Ba, Sr) MgAl10O17: Ak</entry><entry>with Ak = Eu2 + either in combination with Ce3 + and Tb3 +, or in combination with Mn2 +; the proportion of Eu in the activator Ak is preferably> 50%;</entry></row><row><entry>Sr.₆BP₅O₂₀: Eu2 +</entry><entry /></row><row><entry>Sr.₂P₂O₇: (Eu²⁺, Tb³⁺)</entry><entry>together with Eu and Tb</entry></row><row><entry>BaSi₂O₅: Eu²⁺</entry><entry /></row></tbody></tgroup></table></tables><tables id="tabl0003" num="0003"><table frame="none"><title><u style="single">Table 3: Phosphors emitting red (orange-red to deep red)</u></title><tgroup cols="2" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="50mm" /><colspec colnum="2" colname="col2" colwidth="116mm" /><tbody><row><entry>Ln₂O₂St: Ak3 +</entry><entry>where Ln = at least one of the metals Gd, La, Lu alone or in combination with Y (Y is preferably at most 40%; in particular, La is at least 10%); and with St = at least one of the elements S, Se, Te; and where Ak = Eu alone or in combination with Bi;</entry></row><row><entry>Ln2WmO6: Ak3 +</entry><entry>where Ln = at least one of the metals Y, Gd, La, Lu; and with Wm = at least one of the elements W, Mo, Te; and where Ak = Eu alone or in combination with Bi;</entry></row><row><entry>(Zn, Cd) S: Ag +</entry><entry>Zn and Cd are used only in combination; Zn is preferably <Cd;</entry></row><row><entry>Mg₂₈Ge_7.5O₃₈F₁₀: Mn⁴⁺</entry><entry /></row><row><entry><u style="single">Sr.</u>_{<u style="single">2</u>}<u style="single">P</u>_{<u style="single">2</u>}<u style="single">O</u>_{<u style="single">7</u>}<u style="single">: Eu²⁺, Mn²⁺</u></entry><entry /></row><row><entry>M₃MgSi₂O₈: Eu²⁺, Mn²⁺</entry><entry>with M = at least one of the metals Ca, Ba, Sr,</entry></row><row><entry>(M1) 2 (M2) (BO3) 2: Eu2 +</entry><entry>with M1 = at least one of the metals Ba, Sr; and with M2 is at least one of the metals Mg, Ca; the proportion of Ba in the cation M1 is preferably at least 80%; the proportion of Mg in metal M2 is preferably at least 70%.</entry></row></tbody></tgroup></table></tables>

0020It is noted that the activator generally replaces a portion of the leading cation (= metal, in particular a lanthanide Ln), for example MS: Eu (5%) stands for M_1-0.05Eu_0.05S.

0021The phrase "M = at least one of the metals X, Y;" means either the metal X or the metal Y alone or a combination of both metals, that is M = X_aY_b with a + b = 1.

0022In the case of a white LED, a structure similar to that described in the prior art mentioned at the outset is used. GaInN or GaN or GaInAlN is preferably used as the UV diode (primary radiation source). For example, it has a peak wavelength of 400 nm and a half-width of 20 nm. The diode substrate is coated directly or indirectly with a suspension of three phosphors, one each with an emission maximum in the red, green and blue spectral range. At least one of these phosphors is selected from Tables 1 to 3, and is combined either with known phosphors or with phosphors from the other tables. The phosphor mixture is baked at about 200 ° C. A color rendering of typically 80 is thus achieved.

0023The invention will be explained in more detail below with the aid of several exemplary embodiments. Show it:<dl id="dl0001" compact="compact"><dt>Figure 1</dt><dd>a semiconductor device that serves as a light source (LED) for white light;</dd><dt>Figure 2</dt><dd>a lighting unit with phosphors according to the present invention;</dd><dt>Figure 3 to 17</dt><dd>the emission spectrum of LEDs with different phosphor mixtures according to the present invention.</dd></dl>

Description of the drawings

0024For use in a white LED together with a GainN chip, for example, a structure similar to that in <patcit id="pcit0011" dnum="US5998925A"><text>US 5,998,925</text></patcit> described used. The construction of such a light source for white light is shown in<figref idref="f0001">Figure 1</figref> explicitly shown. The light source is a semiconductor component (chip 1) of the InGaN type with a peak emission wavelength of 420 nm and a half-width of 25 nm with a first and second electrical connection 2, 3, which is embedded in an opaque basic housing 8 in the region of a recess 9 . One of the connections 3 is connected to the chip 1 via a bonding wire 14. The recess has a wall 17 which serves as a reflector for the blue primary radiation of the chip 1. The recess 9 is filled with a casting compound 5, which contains an epoxy casting resin (80 to 90% by weight) and phosphor pigments 6 (less than 15% by weight) as main components. Other small proportions include methyl ether and Aerosil. The phosphor pigments are a mixture. The first conversion phosphor is selected from Table 1. The second phosphor is selected from Tab. 2 and the third from Tab. 3.

0025In <figref idref="f0001">Figure 2</figref> a section of a surface light 20 is shown as a lighting unit. It consists of a common carrier 21 onto which a cuboid outer housing 22 is glued. Its top is provided with a common cover 23. The cuboid housing has cutouts in which individual semiconductor components 24 are accommodated. They are UV-emitting diodes with a peak emission of 380 nm. The conversion to white light takes place by means of conversion layers, which sit directly in the casting resin of the individual LEDs, similar to that in <figref idref="f0001">Figure 1</figref> described or layers 25 which are attached to all areas accessible to UV radiation. These include the inner surfaces of the side walls of the housing, the cover and the base part. The conversion layers 25 consist of three phosphors which emit in the yellow, green and blue spectral range using at least one of the phosphors according to the invention from Tables 1 to 3.

0026Some specific exemplary embodiments of phosphors examined in combination are summarized in Tab. 4. It is a summary of suitable phosphors according to the invention and known per se in all three spectral ranges. The experimental number is given in column 1, the chemical formula of the phosphor in column 2, the maximum emission of the phosphor in column 3, and the x and y coordinate coordinates in columns 4 and 5. In Sp. 6 and 7 reflectivity and quantum efficiency (both in percent) are given.

0027The use of ZnS phosphors for LEDs is also particularly preferred. They show good processing behavior in the LED environment. These are primarily the blue-emitting phosphor ZnS: Ag, the green-emitting phosphor ZnS: Cu, Al and the red-emitting phosphor ZnS: Cu, Mn from Table 4. It should be emphasized in particular that a white-emitting phosphor mixture can be realized with these three phosphors, with excitation by an LED with primary radiation in the range 370 to 410 nm, see exemplary embodiment 6 in <figref idref="f0005">Fig. 6</figref>. Since these three phosphors are chemically almost identical materials, they can be processed very well as a phosphor mixture in a casting resin or other resin or with a slurry.<tables id="tabl0004" num="0004"><table frame="topbot"><title>Tab. 4</title><tgroup cols="6" colsep="0"><colspec colnum="1" colname="col1" colwidth="55mm" /><colspec colnum="2" colname="col2" colwidth="11mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><colspec colnum="5" colname="col5" colwidth="14mm" /><colspec colnum="6" colname="col6" colwidth="16mm" /><thead><row><entry valign="top"><i>No formula</i></entry><entry align="center" valign="top"><i>Em</i></entry><entry align="center" valign="top"><i>x</i></entry><entry align="center" valign="top"><i>y</i></entry><entry align="center" valign="top"><i>R (%)</i></entry><entry align="center" valign="top"><i>QE (%)</i></entry></row></thead><tbody><row rowsep="0"><entry>1 Ba₃MgSi₂O₈: Eu (5%)</entry><entry align="center">440</entry><entry align="center">0,16</entry><entry align="center">0,07</entry><entry align="center">42</entry><entry align="center">50</entry></row><row rowsep="0"><entry>2nd (Ba_0.15Sr._0.85)₅(PO₄)₃Cl: Eu2 +</entry><entry align="center">448</entry><entry align="center">0,15</entry><entry align="center">0,05</entry><entry align="center">46</entry><entry align="center">76</entry></row><row rowsep="0"><entry>3rd ZnS: Ag</entry><entry align="center">452</entry><entry align="center">0,14</entry><entry align="center">0,07</entry><entry align="center">76</entry><entry align="center">63</entry></row><row rowsep="0"><entry>4th (Ba, Sr) MgAl₁₀O₁₇: Eu2 +</entry><entry align="center">454</entry><entry align="center">0,15</entry><entry align="center">0,08</entry><entry align="center">49</entry><entry align="center">83</entry></row><row rowsep="0"><entry>5 SrMgAl₁₀O₁₇: Eu2 +</entry><entry align="center">467</entry><entry align="center">0,15</entry><entry align="center">0,19</entry><entry align="center">63</entry><entry align="center">92</entry></row><row rowsep="0"><entry>6 EuMgAl₁₀O₁₇</entry><entry align="center">481</entry><entry align="center">0,17</entry><entry align="center">0,31</entry><entry align="center">35</entry><entry align="center">63</entry></row><row rowsep="0"><entry>7 ZnS: Cu</entry><entry align="center">506</entry><entry align="center">0,19</entry><entry align="center">0,43</entry><entry align="center">22</entry><entry align="center">48</entry></row><row rowsep="0"><entry>8th Ba_0.74Eu_0.08Al₁₂O_18.82</entry><entry align="center">507</entry><entry align="center">0,22</entry><entry align="center">0,43</entry><entry align="center">52</entry><entry align="center">87</entry></row><row rowsep="0"><entry>9 Approx₆Mg (SiO₄)₄Cl₂: Eu2 +</entry><entry align="center">508</entry><entry align="center">0,17</entry><entry align="center">0,6</entry><entry align="center">34</entry><entry align="center">67</entry></row><row rowsep="0"><entry>10ZnS: Cu</entry><entry align="center">510</entry><entry align="center">0,2</entry><entry align="center">0,46</entry><entry align="center">16</entry><entry align="center">55</entry></row><row rowsep="0"><entry>11 BaMgAl₁₀O₁₇: Eu2 +, Mn2 +</entry><entry align="center">513</entry><entry align="center">0,14</entry><entry align="center">0,21</entry><entry align="center">64</entry><entry align="center">95</entry></row><row rowsep="0"><entry>12th Ba_0.72Eu_0.05Mn_0.05Al₁₂O_18.82</entry><entry align="center">514</entry><entry align="center">0,21</entry><entry align="center">0,46</entry><entry align="center">71</entry><entry align="center">97</entry></row><row rowsep="0"><entry>13 BaMgAl₁₀O₁₇: Eu2 +, Mn2 +</entry><entry align="center">515</entry><entry align="center">0,14</entry><entry align="center">0,65</entry><entry align="center">39</entry><entry align="center">88</entry></row><row rowsep="0"><entry>14 (Sr, Ba) SiO₄: Eu2 +</entry><entry align="center">517</entry><entry align="center">0,23</entry><entry align="center">0,61</entry><entry align="center">54</entry><entry align="center" /></row><row rowsep="0"><entry>15 SrAl₂O₄: Eu2 +</entry><entry align="center">523</entry><entry align="center">0,29</entry><entry align="center">0,58</entry><entry align="center">28</entry><entry align="center">77</entry></row><row rowsep="0"><entry>16 ZnS: Cu, Al</entry><entry align="center">534</entry><entry align="center">0,31</entry><entry align="center">0,61</entry><entry align="center">29</entry><entry align="center">83</entry></row><row rowsep="0"><entry>17th YBO₃: (Ce3 +, Rb3 +) (9.5% / 5%)</entry><entry align="center">545</entry><entry align="center">0,34</entry><entry align="center">0,59</entry><entry align="center">80</entry><entry align="center">69</entry></row><row rowsep="0"><entry>18th Approx₈Mg (SiO₄)₄Cl₂: Eu2 +, Mn2 +</entry><entry align="center">550</entry><entry align="center">0,38</entry><entry align="center">0,57</entry><entry align="center">30</entry><entry align="center">61</entry></row><row rowsep="0"><entry>19th Sr._1.95Ba_0.03Eu_0.02SiO₄</entry><entry align="center">563</entry><entry align="center">0,44</entry><entry align="center">0,53</entry><entry align="center">21</entry><entry align="center" /></row><row rowsep="0"><entry>20 Sr.₂P₂O₇: Eu2 +, Mn2 +</entry><entry align="center">570</entry><entry align="center">0,32</entry><entry align="center">0,27</entry><entry align="center">63</entry><entry align="center">46</entry></row><row rowsep="0"><entry>21 ZnS: Cu.Mn</entry><entry align="center">585</entry><entry align="center">0,49</entry><entry align="center">0,45</entry><entry align="center">19</entry><entry align="center">44</entry></row><row rowsep="0"><entry>22 DG₂MoO₆: Eu3 + (20%)</entry><entry align="center">610</entry><entry align="center">0,66</entry><entry align="center">0,34</entry><entry align="center">50</entry><entry align="center" /></row><row rowsep="0"><entry>23 Y₂W_0.98Mon_0.02O₆: Eu³⁺</entry><entry align="center">612</entry><entry align="center">0,61</entry><entry align="center">0,38</entry><entry align="center">68</entry><entry align="center">73</entry></row><row rowsep="0"><entry>24th Y₂WHERE₆: Eu3 +, Bi3 + (7.5%, 0.5%)</entry><entry align="center">612</entry><entry align="center">0,64</entry><entry align="center">0,36</entry><entry align="center">52</entry><entry align="center" /></row><row rowsep="0"><entry>25th Lu₂WHERE₆: Eu3 +, Bi3 + (7.6%, 1%)</entry><entry align="center">612</entry><entry align="center">0,64</entry><entry align="center">0,36</entry><entry align="center">65</entry><entry align="center" /></row><row rowsep="0"><entry>26 SrS: Eu2 + (2%)</entry><entry align="center">616</entry><entry align="center">0,63</entry><entry align="center">0,37</entry><entry align="center">52</entry><entry align="center">91</entry></row><row rowsep="0"><entry>27 La₂TeO₆: Eu3 + (%)</entry><entry align="center">617</entry><entry align="center">0,66</entry><entry align="center">0,34</entry><entry align="center">76</entry><entry align="center" /></row><row rowsep="0"><entry>28 (La, Y)₂O₂S: Eu3 + (..)</entry><entry align="center">626</entry><entry align="center">0,67</entry><entry align="center">0,33</entry><entry align="center">84</entry><entry align="center">73</entry></row><row rowsep="0"><entry>29 Sr.₂Si₅N / A₈: Eu2 + (10%)</entry><entry align="center">636</entry><entry align="center">0,64</entry><entry align="center">0,36</entry><entry align="center">12</entry><entry align="center">70</entry></row><row><entry>30th (Ba, Ca, Sr) MgSi₂O₆: Eu, Mn</entry><entry align="center">657</entry><entry align="center">0,39</entry><entry align="center">0,16</entry><entry align="center">47</entry><entry align="center">52</entry></row></tbody></tgroup></table></tables>

0028The phosphor No. 14 (Sr, Ba) SiO₄: Eu2 + is so broadband in the green that there is no separate red component here.

0029Finally, Tab. 6 shows 15 exemplary embodiments of specific combinations of phosphors from Tab. 4 in connection with a primary light source (UV-LED) with an emission peak in the range 370 to 420 nm. The individual UV diodes are summarized in Tab. 5, in which the emission peak and the color location (as far as defined, i.e. from 380 nm) of the individual diodes is given.

0030In Columns 1 to 4 of Tab. 6 the information from Tab. 4 is inserted again for better comparison. The usefulness of the individual phosphors for excitation at different wavelengths is recorded in columns 5 to 10, specifically for the short-wave diodes with emission peak at 370 to 420 nm in steps of 10 nm. The following 15 columns show concrete examples (referred to as Ex 1 to Ex 15) of an RGB mixture, i.e. the combination of the short-wave LED (the second line indicates the selected peak emission) with three phosphors from the red, green and blue spectral range. The number given in the respective column denotes the relative proportion of the spectral emission.

0031In the case of a strongly short-wave UV diode, below 380 nm, the UV diode does not provide any part in the secondary emission, also because of the strong absorption by the three phosphors.

0032From a primary emission of 380 nm, however, the diode delivers a small proportion of the blue, which increases with increasing wavelength, in addition to the blue phosphor. This proportion appears in Tab. 5 as an additional fourth contribution.

0033Finally, the measured color location coordinates of the overall system are entered in the last two lines of Table 6, which cover a wide range of white tones in the color table. The spectral distribution of this system is in the<figref idref="f0002">Figures 3</figref> (corresponding to Ex 1) to 17 (corresponding to Ex 15).

0034The particularly suitable phosphors for use in three-color mixtures under primary irradiation at 370 to 420 nm are the blue-emitting phosphors No. 2, 4 and 6, and the green-emitting phosphors 8, 9, 10, 13, 15, 16, 17 and 18 and the red-emitting phosphors 26, 28 and 29 have been proven.

0035Exemplary embodiment no. 15 uses a blue-emitting diode with 420 nm peak emission with such a high intensity that it can fully replace the blue phosphor and only requires two additional phosphors in the green and red.<tables id="tabl0005" num="0005"><table frame="all"><title>Tab. 5</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="12mm" /><colspec colnum="2" colname="col2" colwidth="11mm" /><colspec colnum="3" colname="col3" colwidth="12mm" /><colspec colnum="4" colname="col4" colwidth="12mm" /><thead><row><entry align="center" valign="top">No.</entry><entry align="center" valign="top">Em</entry><entry align="center" valign="top">x</entry><entry align="center" valign="top">y</entry></row></thead><tbody><row><entry align="center">UV1</entry><entry align="center">370</entry><entry align="center" /><entry align="center" /></row><row><entry align="center">UV2</entry><entry align="center">380</entry><entry align="center">0,2</entry><entry align="center">0,14</entry></row><row><entry align="center">UV3</entry><entry align="center">390</entry><entry align="center">0,19</entry><entry align="center">0,09</entry></row><row><entry align="center">UV4</entry><entry align="center">400</entry><entry align="center">0,18</entry><entry align="center">0,05</entry></row><row><entry align="center">UV5</entry><entry align="center">410</entry><entry align="center">0,18</entry><entry align="center">0,03</entry></row><row><entry align="center">UV6</entry><entry align="center">420</entry><entry align="center">0,17</entry><entry align="center">0,02</entry></row></tbody></tgroup></table></tables><tables id="tabl0006" num="0006"><img file="EP1970970A2_D0001.tif" /></tables>