Abstract
An optoelectronic component is disclosed. In an embodiment, an optoelectronic component includes a semiconductor chip configured to emit primary radiation having a peak wavelength between 420 nm inclusive and 480 nm inclusive and a conversion element including a first converter material configured to partially convert the primary radiation into secondary radiation in a green range of the electromagnetic spectrum and a second converter material configured to partially convert the primary radiation into a secondary radiation in a red region of the electromagnetic spectrum, wherein the second converter material including a first red phosphor of the formula (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and a second red phosphor of the formula(M).sub.2-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 where M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, and wherein the optoelectronic device is configured to emit white total radiation.
Claims
1. An optoelectronic device comprising: a semiconductor chip configured to emit primary radiation having a peak wavelength between 420 nm inclusive and 480 nm inclusive; and a conversion element comprising: a first converter material configured to partially convert the primary radiation into secondary radiation in a green range of the electromagnetic spectrum; and a second converter material configured to partially convert the primary radiation into a secondary radiation in a red region of the electromagnetic spectrum, wherein the second converter material comprising a first red phosphor of the formula (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and a second red phosphor selected from the following formula: (M).sub.2-xEu.sub.x, Si.sub.2Al.sub.2N.sub.6 where M=Sr, Ca, Ba, and/or Mg and 0.001x 0.2, wherein the second red phosphor of the formula (M).sub.2-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 comprises: [Sr(Sr.sub.aM.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6, where M=Ca, Ba, Zn and/or Mg, 0.5a1 and 0.001X0.2, (M).sub.1-xEu.sub.xAlSiN.sub.3*Si.sub.2N.sub.2O, where M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, or (M).sub.1-XEu.sub.x-[LiAl.sub.3N.sub.4] with M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, and wherein the optoelectronic device is configured to emit white total radiation.
2. The optoelectronic device according to claim 1, wherein the second red phosphor comprises the formula: [Sr(Sr.sub.aM.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6, where M=Ca, Ba, Zn, and/or Mg with 0.5a1 and 0.001x0.2.
3. The optoelectronic device according to claim 1, wherein the first converter material comprises converter particles having a quantum structure with barrier layers and quantum layers or a green phosphor.
4. The optoelectronic device according to claim 3, wherein the first converter material comprises the converter particles having the quantum structure with the barrier layers and the quantum layers, and wherein the barrier layers and the quantum layers are arranged alternately.
5. The optoelectronic device according to claim 3, wherein the first converter material comprises the green phosphor selected from the group consisting of orthosilicates, nitridoorthosilicates, beta-SiAlON and garnets.
6. The optoelectronic device according to claim 5, wherein the first converter material comprises a green orthosilicate phosphor of the formula (AE).sub.2-yEu.sub.ySiO.sub.4 where AE=Sr, Ca, Ba and/or Mg and 0.001y0.2.
7. The optoelectronic device according to claim 5, wherein the first converter material comprises a green nitridoorthosilicate phosphor of the formula (AE).sub.2-b-y(RE).sub.bEu.sub.ySiO.sub.4-bN.sub.b, wherein AE=Sr, Ba, Ca and/or Mg, RE=Rare earth metals, 0.002y0.4, 0b<2-y, or (AE).sub.2-c-y(RE).sub.xEu.sub.ySi.sub.1-dO.sub.4-c-2dN.sub.c where AE=Sr, Ba, Ca and/or Mg, RE=Rare Earth Metals, 0.002y0.4, 0c2-y and 0d<1.
8. The optoelectronic device according to claim 5, wherein the first converter material comprises a green beta-SiAlON phosphor of the formula Si.sub.6-z-2yEu.sub.yAl.sub.zO.sub.zN.sub.8-z with 0z6 and 0.001y0.2.
9. The optoelectronic device according to claim 5, wherein the first converter material comprises a green garnet phosphor of the formula (Lu,Y,Gd,Tb).sub.3-yCe.sub.y(Al,Ga).sub.5O.sub.12 with 0.003y0.6.
10. The optoelectronic device according to claim 1, wherein the conversion element is part of a potting of the semiconductor chip or the conversion element forms the potting.
11. The optoelectronic device according to claim 1, wherein the conversion element is formed as a layer and is disposed directly on the semiconductor chip.
12. The optoelectronic device according to claim 1, wherein the second red phosphor comprises the formula: [Sr(Sr.sub.aCa.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 with 0.8a1 and 0.001x0.2.
13. A backlighting color filter system comprising: the optoelectronic device according to claim 1.
14. A lighting unit comprising: the optoelectronic device according to claim 1; and a color filter system comprising a blue filter, a green filter and a red filter configured to filter the white total radiation of the optoelectronic device to radiation of a transmission spectrum.
15. An optoelectronic device comprising: a semiconductor chip configured to emit primary radiation having a peak wavelength between 420 nm inclusive and 480 nm inclusive; and a conversion element comprising: a first converter material configured to partially convert the primary radiation into secondary radiation in a green range of the electromagnetic spectrum, wherein the first converter material comprises converter particles having a quantum structure with barrier layers and quantum layers or a green phosphor; and a second converter material configured to partially convert the primary radiation into a secondary radiation in a red region of the electromagnetic spectrum, wherein the second converter material comprising a first red phosphor of the formula (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and a second red phosphor selected from the following formula: (M).sub.2-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 where M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, wherein the second red phosphor of the formula (M).sub.2-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 comprises: [Sr(Sr.sub.aM.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6, where M=Ca, Ba, Zn and/or Mg, 0.5a1 and 0.001x0.2, (M).sub.1-xEu.sub.xAlSiN.sub.3*Si.sub.2N.sub.2O, where M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, (M).sub.2-2xEu.sub.2xSi.sub.5N.sub.8, where M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, or (M).sub.1-xEu.sub.x-[LiAl.sub.3N.sub.4] with M=Sr, Ca, Ba, and/or Mg and 0.001x0.2, and wherein the optoelectronic device is configured to emit white total radiation.
16. The optoelectronic device according to claim 15, wherein the conversion element is part of a potting of the semiconductor chip or the conversion element forms the potting.
17. The optoelectronic device according to claim 15, wherein the conversion element is formed as a layer and is disposed directly on the semiconductor chip.
18. An optoelectronic device comprising: a semiconductor chip configured to emit primary radiation having a peak wavelength between 420 nm inclusive and 480 nm inclusive; and a conversion element comprising: a first converter material configured to partially convert the primary radiation into secondary radiation in a green range of the electromagnetic spectrum, and a second converter material configured to partially convert the primary radiation into a secondary radiation in a red region of the electromagnetic spectrum, wherein the second converter material comprising a first red phosphor of the formula (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and a second red phosphor comprising the formula: [Sr(Sr.sub.aM.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6, where M=Ca, Ba, Zn, and/or Mg with 0.5a1 and 0.001x0.2, and wherein the optoelectronic device is configured to emit white total radiation.
19. The optoelectronic device according to claim 18, wherein the conversion element is part of a potting of the semiconductor chip or the conversion element forms the potting.
20. The optoelectronic device according to claim 18, wherein the conversion element is formed as a layer and is disposed directly on the semiconductor chip.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further advantageous embodiments and developments of the invention result from the exemplary embodiments described in the following in connection with the figures.
(2) FIGS. 1 to 4 show emission spectra of various exemplary embodiments of optoelectronic devices; and
(3) FIGS. 5 to 6 show schematic side views of various embodiments of optoelectronic devices.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
(4) FIG. 1 shows an emission spectrum of an exemplary embodiment of an optoelectronic device. On the x-axis the wavelength is plotted in nm and on the y-axis the emission E is plotted. Shown are the primary radiation I, the secondary radiation of the first converter material, a beta-SiAlON, in the green spectral range II.sub.G, the secondary radiation of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ II.sub.R1, and the second red phosphor (Sr,Ca).sub.1-xEu.sub.x[LiAl.sub.3N.sub.4] with 0.001x0.2 II.sub.R2. The emission spectra I, II.sub.G, II.sub.R1 and II.sub.R2 show a small half-width and a high overlap with the transmission range of a standard blue filter, a standard green filter or a standard red filter. In addition, the emission spectra I and II.sub.G or II.sub.G and II.sub.R1 and II.sub.R2 show hardly any overlap with each other, whereby a high color saturation of the individual colors can be achieved, since the individual emissions spectrally respond to only or almost only one color of a color filter system. Superimposed, I, II.sub.G, II.sub.R1 and II.sub.R2 produce the white total radiation E.sub.W. The color location of the white total radiation in the CIE color space (1931) is Cx=0.3263 and Cy=0.2917 and a correlated color temperature of 5896 K. By using the first red phosphor and the second red phosphor, a large color space can be covered with advantage. In addition, high brightness can be achieved because the dominant wavelength of the first red phosphor is closer to the maximum eye sensitivity at 555 nm compared to the second red phosphor, which means that the total secondary radiation emitted in the red spectral range has a higher overlap with the eye sensitivity curve. Due to the narrow-band emission of the second red phosphor with a half-width below 60 nm, there is no or only a small amount of radiation outside the visible spectral range, which increases the luminescence efficiency of the device.
(5) The emission peaks of the first and second red phosphors show a very large overlap with the transmission range of a standard red filter, so that only little light is lost and the achievable color space is large. With the invention of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and the second red phosphor (Sr,Ca).sub.1-xEu.sub.x-[LiAl.sub.3N.sub.4] two essential aspects for backlighting applications can be fulfilled: a high brightness and the coverage of a large color space. In comparison, the use of (Ca,Sr)AlSiN.sub.3:Eu as a second red phosphor has proven to be less suitable, since it emits too broadly with a half-width of 90 nm, resulting in luminescence losses.
(6) FIG. 2 shows an emission spectrum of an exemplary embodiment of an optoelectronic device. On the x-axis the wavelength is plotted in nm and on the y-axis the emission E is plotted. Shown are the primary radiation I, the secondary radiation of the first converter material, a beta-SiAlON, in the green spectral range II.sub.G, the secondary radiation of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ II.sub.R1 and the second red phosphor [Sr(Sr.sub.aCa.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 with 0.5a1 and 0.001x0.2 II.sub.R2. The emission spectra I, II.sub.G, II.sub.R1 and II.sub.R2 are very narrow-band and show a high overlap with the transmission range of a standard blue filter, a standard green filter or a standard red filter. In addition, the emissions I and II.sub.G and II.sub.G or and II.sub.G and II.sub.R1 and II.sub.R2 show hardly any overlap with each other, whereby a high color saturation of the individual colors can be achieved, since the individual emissions spectrally respond only or almost only one color of a color filter system. Superimposed, I, II.sub.G, II.sub.R1 and II.sub.R2 produce the white total radiation Ew. The color location of the white total radiation in the CIE color space (1931) are Cx=0.3013 and Cy=0.2893 and a correlated color temperature of 7903 K. Due to the narrow-band emissions of the first and second red phosphors, there is little or no radiation outside the visible spectral range, which increases the device's luminescence efficiency. The emission peaks of the first and second red phosphor show a very large overlap with the transmission range of a standard red filter, so that only little light is lost and the achievable color space is large. In comparison, the use of (Ca,Sr)AlSiN.sub.3:Eu as a second red phosphor has proven to be less suitable, as it emits too broadly with a half-width of 90 nm, resulting in luminescence losses.
(7) FIG. 3 shows an emission spectrum of an exemplary embodiment of an optoelectronic device. On the x-axis the wavelength is plotted in nm and on the y-axis the emission E is plotted. Shown are the primary radiation I, the secondary radiation of the first converter material, I, converter particles with a quantum structure with barrier layers and quantum layers arranged alternately in the green spectral range II.sub.G, the secondary radiation of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ II.sub.R1 and of the second red phosphor [Sr(Sr.sub.aCa.sub.1-a)].sub.1-xEu.sub.xSi.sub.2Al.sub.2N.sub.6 with 0.5a1 and 0.001x0.2 II.sub.R2. The emissions I, II.sub.G, II.sub.R1 and II.sub.R2 are very narrow-band and show a high overlap with the transmission range of a standard blue filter, a standard green filter or a standard red filter. In addition, the emissions I and II.sub.G or and II.sub.G and II.sub.R1 and II.sub.R2 show hardly any overlap with each other, whereby a high color saturation of the individual colors can be achieved, since the individual emissions spectrally respond only or almost only one color of a color filter system. Superimposed, I, II.sub.G, II.sub.R1, and II.sub.R2 produce the white total radiation Ew. The color location of the white total radiation in the CIE color space (1931) is Cx=0.3138 and Cy=0.2722 and a correlated color temperature of 7167 K. Due to the narrow-band emissions of the first and second red phosphor, there is little or no radiation outside the visible spectral range, which increases the device's luminescence efficiency. The emission peaks of the first and second red phosphor advantageously show a very large overlap with the transmission range of a standard red filter, so that only little light is lost and the achievable color space is large. In comparison, the use of (Ca,Sr)AlSiN.sub.3:Eu as a second red phosphor has proven to be less suitable, as it emits too broadly with a half-width of 90 nm, resulting in luminescence losses.
(8) FIG. 4 shows an emission spectrum of an exemplary embodiment of an optoelectronic device. On the x-axis the wavelength is plotted in nm and on the y-axis the emission E is plotted. Shown are the primary radiation I, the secondary radiation of the first converter material, converter particles having a quantum structure with barrier layers and quantum layers arranged alternately in the green spectral region II.sub.G, the secondary radiation of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ II.sub.R1 and the second red phosphor (Sr,Ca).sub.1-xEu.sub.x[LiAl.sub.3N.sub.4] with 0.001x0.2 II.sub.R2. The emissions I, II.sub.G, II.sub.R1, and II.sub.R2 are very narrowband and show a high overlap with the transmission range of a standard blue filter, a standard green filter or a standard red filter. In addition, the emissions I and II.sub.G or and II.sub.G and II.sub.R1, and II.sub.R2 show hardly any overlap with each other, whereby a high color saturation of the individual colors can be achieved, since the individual emissions spectrally respond only or almost only one color of a color filter system. Superimposed, I, II.sub.G, II.sub.R1 and II.sub.R2 produce the white total radiation Ew. The color location of the white total radiation in the CIE color space (1931) is Cx=0.2954 and Cy=0.2929 and a correlated color temperature of 8318 K. By using the first red phosphor and the second red phosphor, it is advantageous to cover a large range of the red spectral range, thus covering a large color space. In addition, high brightness can be achieved because the dominant wavelength of the first red phosphor is closer to the maximum eye sensitivity at 555 nm compared to the second red phosphor, resulting in a higher overlap of the emitted secondary radiation with the eye sensitivity curve. Due to the narrow-band emission of the second red phosphor with a half-width below 60 nm, there is no or only a small amount of radiation outside the visible spectral range, which increases the luminescence efficiency of the device. The emission peaks of the first and second red phosphor show a very large overlap with the transmission range of a standard red filter, so that only little light is lost and the achievable color space is large. Thus, with the use of the first red phosphor (K,Na).sub.2(Si,Ti)F.sub.6:Mn.sup.4+ and the second red phosphor (Sr,Ca).sub.1-xEu.sub.x[LiAl.sub.3N.sub.4] in accordance with the invention, two essential aspects for backlighting applications can be fulfilled: maximum brightness and coverage of a large color space. In comparison, the use of (Ca,Sr)AlSiN.sub.3:Eu as a second red phosphor has proven to be less suitable, as it emits too broadly with a half-width of 90 nm, resulting in luminescence losses.
(9) The exemplary embodiment of an optoelectronic device 1 shown in FIG. 5 shows a semiconductor chip 2 that emits primary radiation in the blue region of the electromagnetic spectrum during operation of the device, for example, with a peak wavelength of 460 nm. The semiconductor chip is based on aluminum indium gallium nitride. The semiconductor chip 2 is mounted on a first connection 4 and a second connection 5 and electrically connected to these connections. The connections 4, 5 are electrically connected with through-connections 4a and 5a.
(10) In the exemplary embodiment shown in FIG. 5, the first and second electrical connections 4, 5 are embedded in an opaque, e.g., prefabricated, housing 10 with a recess 11. Prefabricated means that the housing 10 is already formed at the connections 4 and 5, for example, by injection moulding, before the semiconductor chip 2 is mounted on the connections 4, 5. The housing, for example, comprises an opaque plastic and the recess 11 is configured as a reflector for the primary and secondary radiation, whereby the reflection can be realized by the housing material or by a suitable coating of the inner walls of the recess 11. The connections 4, 5 are made of a metal that has a reflectivity for blue primary radiation greater than 60%, preferably greater than 70%, particularly preferred greater than 80%, such as silver or gold.
(11) The conversion element 6 in the exemplary embodiment of FIG. 5 is formed in the form of a potting and fills the recess 11, as shown in FIG. 5. The conversion element 6 comprises a silicone or an epoxy in which particles of a green phosphor, in this case a green beta-SiAlON phosphor, are embedded as the first converter material of formula and particles of a second converter material. The second converter material consists of a first phosphor of the formula K.sub.2SiF.sub.6:Mn.sup.4+ and a second red phosphor of the formula (Sr,Ca).sub.1-xEu.sub.x[LiAl.sub.3N.sub.4] with 0.001x0.2. The particles of the beta-SiAlON phosphor partially convert the primary radiation to a secondary radiation in the green region of the electromagnetic spectrum and the second converter material partially convert the primary radiation to a secondary radiation in the red region of the electromagnetic spectrum. The superposition of the primary radiation and the secondary radiation in the green and red spectral range results in a white total radiation.
(12) In this exemplary embodiment, the total radiation is radiated upwards via the conversion element 6. The total radiation preferably has a color temperature of 4000 K to 30000 K and is therefore preferably close to the Planck's radiation curve or close to the respective isotherms. In the CIE color diagram (1931), for example, the color location of the device are in the range from Cx 0.15-0.40 and Cy 0.15-0.40, preferably in the range from Cx 0.20-0.37 and Cy 0.20-0.37, for color locations, for example. The color location refers to points in or on a color body which is described in the color space with suitable coordinates in its position. The color location represents the color perceived by an observer.
(13) In the exemplary embodiment of an optoelectronic device 1 shown in FIG. 6, the conversion element 6, in contrast to the device in FIG. 5, is formed as a layer which is arranged above the semiconductor chip 2. The layer is arranged above the main radiation exit surface of the semiconductor chip. It is possible that the layer also covers the side walls of the semiconductor chip (not shown here).
(14) The invention is not limited by the description with reference to the exemplary embodiments. Rather, the invention includes each new feature as well as each combination of features, which in particular includes each combination of features in the patent claims, even if that feature or combination itself is not explicitly mentioned in the patent claims or exemplary embodiment.
