DE102009037861A1 - A chloroaluminate compound, a process for the production thereof, a radiation-emitting device comprising the chloroaluminate compound, and a process for producing the radiation-emitting device - Google Patents

Abstract

A chloroaluminate compound, a process for the production thereof, a radiation-emitting device comprising the chloroaluminate compound, and a process for producing the radiation-emitting device. A chloroaluminate compound represented by the general formula: MeEuMnAlOCl wherein at least one member is selected from: Mg, Ca, Sr, Ba, or any combination thereof, and 0 <x <3; 0 ≰ y <3; x + y <3.

Description

Chloroaluminate compound, process for its preparation, radiation-emitting device comprising the chloroaluminate compound and process for producing the radiation-emitting device. This patent application claims the priority of German patent application 10 2009 022 561.7 , the disclosure of which is hereby incorporated by reference.

It a chloroaluminate compound is given according to claim 1, such as a radiation-emitting device containing the chloroaluminate compound includes. Further, a process for producing the chloroaluminate compound as well as a method for producing the radiation-emitting Device specified.

One widespread problem of radiation-emitting devices, For example, white LEDs, that is the brightness and Efficiency of the semiconductor chip of the energization dependent. Does the radiation-emitting device comprises a phosphor, chip and phosphor respond differently to temperature increases, which may be the result of a higher electrical voltage, what the proportion of primary radiation emitted directly from the chip and the secondary radiation converted by the phosphor changed relative to each other. This can in turn result have that the color impression of the of the radiation-emitting Device emitted radiation as a function of the Can change the current supply.

A Object of the embodiments of the radiation-emitting The device is to provide a radiation-emitting device whose Light color of the respective brightness of the semiconductor chip largely is independent.

A Another object is to provide a phosphor which used for such radiation-emitting devices can be.

The The object is achieved by a chloroaluminate compound according to claim 1 solved. Other embodiments of the chloroaluminate compound as well a radiation-emitting device with the chloroaluminate compound are the subject of further claims. Furthermore Also, a process for producing the chloroaluminate compound and the radiation-emitting device claimed.

One embodiment of the invention relates to a chloroaluminate compound according to the general formula: Me ¹ _3-xy Eu _x Mn _y Al ₂ O ₅ Cl ₂ where Me ^{1 represents} at least one element selected from: Mg, Ca, Sr, Ba, or any combination thereof, and 0 <x <3; 0 ≤ y ≤ 3; x + y <3.

A Chloroaluminate compound of the specified composition can by Radiation from the UV range are excited, where they then radiation emitted in the visible range. Because of the stimulating radiation can be largely outside the visible range, Does not wear these or only slightly to the color location the radiation emitted by a radiation-emitting device in which the color locus is determined by the color coordinates of the CIE system can be defined. Thus, the color location is wholly or largely regardless of the brightness of the radiation source which the phosphor is excited. The luminescence properties For example, the percentage of Eu and / or Mn be influenced.

According to a further embodiment of the invention, Me ^{1 is} the following sub-formula: (Sr _1-z Me ² _z ) resulting in the following formula: (Sr _1-z Me ² _z ) _3-xy Eu _x Mn _y Al ₂ O ₅ Cl ₂ where Me ² for at least one element is selected from: Mg, Ca, Ba and 0 ≤ z <1.

The Sr obtained in the compound can be at least partially replaced by a or more of the following elements: Mg, Ca, Ba. By partially exchanging the Sr, the luminescence characteristics such as excitation range or luminescent color influenced become. For example, the exchange of Sr for Ca has one slight shift and the exchange of Sr for Ba a stronger one Shift the emission spectrum to shorter wavelengths to the episode.

In another embodiment of the invention, the chloroaluminate compound may be represented by the general formula: Sr _3-x Eu _x Al ₂ O ₅ Cl ₂ where 0 <x <3.

The chloroaluminate compound according to the general formula Sr _3-x Eu _x Al ₂ O ₅ Cl ₂ can be excited in the UV range and in the short-wave visible range up to about 470 nm. The compound can be excellently excited in the UV range and in the short-wave visible range up to approximately 425 nm. In the latter range, the reflectivity with respect to the excitation radiation is less than 30 percent. This means that only a small amount of radiation is reflected by the conversion material, and a large proportion is absorbed and thus can be converted. The chloroaluminate compound shows intense orange-yellow luminescence. The emission spectrum extends from the blue-green spectral range to the IR and has a half-width of about 167 nm. The orange-yellow emission of the chloroaluminate compound has a very high half-width, which is approximately in the range of 167 nm. The emission is enough from the green to the near IR area.

The maximum of the emission is about 616 nm. For a composition according to the formula Sr _2.9 Eu _0.1 Al ₂ O ₅ Cl ₂ , the color coordinates are approximately at c _x = 0.537 and c _y = 0.448 at an excitation of 360 nm and a measuring range of 380 to 800 nm. Color coordinates are to be understood as the color coordinates according to the CIE system. The dominant wavelength of this phosphor is 585 nm. The dominant wavelength is the wavelength which can be determined as follows: In the CIE color diagram, a line is drawn from the white point to the color locus (c _x , c _y ) of the phosphor and up to the horseshoe-shaped line of the chart. On the horseshoe-shaped line, the wavelengths of the visible spectral range are plotted. The wavelength at which the extended connecting line meets the horseshoe-shaped line is the dominant wavelength.

at in the three previously described embodiments in each case an area for the parameter x of 0.015 ≦ x ≦ 0.3 preferably, from 0.015 ≦ x ≦ 0.15, particularly preferred.

One Less than 0.015 for x would only be one weak issue. With a share of larger 0.15 can already use a deletion of the emission, d. H. the emitted radiation is due to the conversion material absorbed again.

Next The chloroaluminate compound itself will also be a radiation-emitting Apparatus claimed comprising the chloroaluminate compound.

A Embodiment of the radiation-emitting device in this case comprises a radiation source which is a primary radiation emitted and a conversion material in the beam path of the radiation source is arranged. In this case, the conversion material comprises at least one of the chloroaluminate compounds described above. The radiation source emits a primary radiation, which by the Conversion material at least partially into a secondary radiation is converted. The conversion material in this case comprises an inventive Chloroaluminate connection. In the case of the radiation-emitting Device emitted radiation may be both pure secondary radiation act when the primary radiation is complete is converted into secondary radiation. It can work though also be mixed light, which is the mixture of secondary radiation and unconverted primary radiation. The of the Radiation source emitted primary radiation can in this case be tuned to the absorption range of the conversion material.

In a further embodiment of the radiation-emitting Device, the radiation source emits a primary radiation in a wavelength range of 180 nm to 470 nm, wherein the range 280 to 470 nm is preferred

A Such primary radiation can be good through the chloroaluminate compound be absorbed. Thus, a large proportion of the primary radiation be converted into the secondary radiation.

In a further embodiment of the radiation-emitting Device converts the conversion material, the primary radiation in a secondary radiation in the visible spectral range 450 nm to 780 nm, preferably in the range of 450 nm to 700 nm.

Consequently is the primary radiation in the UV or short-wave visible area converted into secondary radiation, the has a broad emission spectrum with respect to the visible region.

In Another embodiment has the spectrum of secondary radiation in the wavelength range from 600 nm to 630 nm an intensity maximum on.

Thereby that the chloroaluminate compound has an intensity maximum in the orange range, it is possible by combination the secondary radiation with a certain amount of blue primary radiation To produce white light.

In In another embodiment, the conversion material with respect to a primary radiation from the wavelength range from 180 nm to 420 nm a reflectivity of less than 30% on.

By the low reflectivity is the conversion material in able to absorb a high proportion of the primary radiation and convert.

about the proportion by weight of the chloroaluminate compound in the conversion material For example, the proportion of the conversion material control converted primary light. Will be too high Proportion of the chloroaluminate compound in relation to Matrix selected, it may be deleted by complete absorption of the secondary radiation come.

It Embodiments are also conceivable in which the conversion material in addition to the chloroaluminate compound comprises further phosphors.

The conversion material can be introduced into a matrix in one embodiment. As a matrix material, for example, a silicone, a Epoxy or another resin can be used. Embodiments are also conceivable in which the conversion material is introduced into a glass or a ceramic.

The Matrix material is preferably permeable to the secondary radiation. They are embodiments conceivable in which the matrix material also for the primary radiation is permeable, but they are also embodiments possible in which the matrix material is the primary radiation partially absorbed.

An embodiment is also possible in which a filter is present in the beam path after the conversion material, which filters out the primary radiation which has not been converted by the conversion material. The filter may comprise, for example, a UV absorber, such as TiO ₂ , but it may for example be formed as a photonic crystal.

In In another embodiment, the radiation-emitting emits Device a mixed light from the primary radiation and the secondary radiation.

In in the event that the primary radiation is not complete is converted into secondary radiation, and the matrix material the unconverted primary radiation is not complete absorbed, and the radiation-emitting device in the beam path has no additional filter that the primary radiation filters out, emits the radiation-emitting device in addition to the secondary radiation also a certain proportion at primary radiation. Through a targeted adjustment of the Proportions of primary radiation and secondary radiation, for example, about the proportion of conversion material can be done in the matrix, the wavelength of the mixed light, which itself from primary radiation and secondary radiation composed, targeted. Thus it is for example possible using blue primary radiation, the radiation-emitting device emits white light.

In Another embodiment comprises the radiation source a semiconductor diode.

The Semiconductor diode can be used to the primary radiation to emit in the UV or short-wave visible range. The semiconductor material may in this case be based, for example, on nitride compound semiconductors or phosphide compound semiconductors. But there are also embodiments possible, in the radiation source as an organic LED (OLED) is used.

"Based on nitride compound semiconductors" in the present context means that the active epitaxial layer sequence or at least one layer thereof comprises a nitride III / V compound semiconductor material, preferably Al _n Ga _m In _{1 nm} N, where 0 ≦ n ≦ 1 , 0 ≤ m ≤ 1 and n + m ≤ 1. However, this material does not necessarily have to have a mathematically exact composition according to the above formula. Rather, it may comprise one or more dopants as well as additional constituents which do not substantially alter the characteristic physical properties of the Al _n Ga _m In _1-nm N material. For the sake of simplicity, however, the above formula contains only the essential constituents of the crystal lattice (Al, Ga, In, N), even if these may be partially replaced by small amounts of other substances.

In this context, "based on phosphide compound semiconductors" means that the semiconductor body, in particular the active region, preferably comprises Al _n Ga _m In _1-nm P, where 0 ≦ n ≦ 1, 0 ≦ m ≦ 1 and n + m ≦ 1 is, preferably with n ≠ 0 and / or m ≠ 0. This material does not necessarily have to have a mathematically exact composition according to the above formula. Rather, it may include one or more dopants as well as additional ingredients that do not substantially alter the physical properties of the material. For the sake of simplicity, however, the above formula includes only the essential constituents of the crystal lattice (Al, Ga, In, P), even though these may be partially replaced by small amounts of other substances.

Next The chloroaluminate compound itself will also become a process too claims its production.

A variant of the production process for the preparation of one of the chloroaluminate compound described above comprises the process steps:
A) Provision of a powder mixture comprising in each case a stoichiometric amount based on the composition Me ¹ _3-x Eu _x Al ₂ O ₅ Cl ₂ of Me ¹ CO ₃ and Me ¹ Cl ₂ , Al ₂ O ₃ , Eu ₂ O ₃ , B) Homogenizing the powder mixture from A), and C) annealing the powder mixture from B).

By appropriate choice of the amount of starting materials, the proportion of Eu is determined, with which the compound is doped. By appropriate selection of the carbonates or chlorides, the corresponding composition of Me ^{1 is} controlled, and the chloride content in the product. After homogenization of the powder mixture, the powder mixture is subsequently annealed.

In a further process variant, the powder mixture in process step A) additionally comprises MnO ₂ and the stoichiometric amounts thus relate to the composition Me ¹ _3-xy Eu _x Mn _y Al ₂ O ₅ Cl ₂ .

In Another variant of the method is the temperature range for the annealing in process step C) in the range of 1000 ° C. to 1400 ° C, preferably in the range of 1000 ° C. up to 1250 ° C.

In In another variant of the method, the annealing takes place in the Process step C) in the forming gas stream.

Next the process for producing the chloroaluminate compound also a method for producing a radiation-emitting Device claimed that such a chloroaluminate compound includes.

A Process variant for the preparation of one of the previously described radiation-emitting devices comprises the process steps: a) providing a radiation source, the primary radiation b) introducing a conversion material into a matrix material, c) introducing the matrix material containing the conversion material includes, in the beam path of the radiation source, so that at least a portion of the primary radiation through the conversion material is converted into a secondary radiation. This is for the conversion material uses a material which a compound according to one of the previously described Chloroaluminate compound includes.

in the Process step a) can be both a LED as a radiation source also an OLED can be used. As matrix material in process step b) For example, a silicone, an epoxy or other resin be used. The introduction of the matrix material in the process step c) can, for example, by the direct application of the matrix material on the radiation exit surface of the radiation source respectively. The application can be made so that on the radiation source a layer formed, but it can also be done by the entire radiation source is poured into the matrix material. But there are also variants possible in which the matrix material for example, applied as a layer on a transparent support, and then the carrier with the matrix material is introduced into the beam path.

in the The following are variants of the invention based on figures and Embodiments explained in more detail become.

1 shows a schematic side view of an embodiment in which the entire primary radiation is converted into secondary radiation.

2 shows a schematic side view of an embodiment in which only a portion of the primary radiation is converted into secondary radiation.

3 shows a schematic side view of an embodiment in which the matrix is formed as a layer on the radiation source.

4 shows a schematic side view of an embodiment in which the inner walls of the housing are chamfered.

5 shows two emission spectra (I and II), in each case the relative intensity (I _r ) was plotted against the wavelength (λ).

6 shows two spectra (I and II), in which each of the reflectivity (R) was plotted against the wavelength (λ).

The 1 shows a schematic side view of an embodiment of the radiation-emitting device 1 , The radiation-emitting device 1 this includes a housing 10 which is pot-shaped. On the inside of the bottom surface of the housing 10 are two printed circuit boards 11 arranged. On one of the two circuit boards 11 is the radiation source 4 arranged so that they have a centered position with respect to the housing 10 occupies. The top of the radiation source 4 is over a bond wire 12 with the circuit board spaced from the radiation source 11 electrically connected. Thus stands the radiation source 4 now in electrically conductive contact with each of the two circuit boards 11 , By applying voltage to the two printed circuit boards 11 can the radiation source 4 primary radiation 2 emit. The entire radiation source 4 is in the case 10 with a matrix 13 shed. Into the matrix 13 Here is the conversion material 5 embedded. The concentration of the conversion material 5 is chosen so that the total emitted primary radiation 2 through the conversion material 5 in secondary radiation 3 is converted. By the complete conversion of the primary radiation 2 in secondary radiation 3 emits the radiation-emitting device 1 over its radiation exit surface 14 excluding secondary radiation 3 , The complete conversion of the primary radiation 2 in secondary radiation 3 can, for example, the appropriate concentration of the conversion material 5 in the matrix 13 be achieved.

In the in 2 illustrated embodiment of a further radiation-emitting device, the housing 10 , the lyre plates 11 , the radiation source 4 and the bond wire 12 analogous to that in 1 illustrated embodiment arranged. However, here is the concentration of the conversion material 5 in the matrix 13 chosen so that only part of the primary radiation 2 in secondary radiation 3 is converted. Thus, the radiation emitted lung-emitting device 1 a mixed light 6 which is the primary radiation 2 and the secondary radiation 3 composed.

3 shows the schematic side view of another embodiment of the radiation-emitting device 1 , The radiation source 4 is here on a circuit board 11 arranged. The top of the radiation source 4 is over a bond wire 12 with another circuit board 11 electrically connected. The radiation source 4 is thus at the top or bottom respectively electrically conductive with a circuit board 11 connected. On top of the radiation source 4 is a conversion layer of the matrix 13 arranged in which the conversion material 5 is embedded. The of the radiation source 4 emitted primary radiation 2 is going through the matrix 13 through the conversion material 5 in secondary radiation 3 converted. The radiation-emitting device 1 thus emits exclusively the secondary radiation 3 , Yes, according to the thickness of the conversion layer or concentration of the conversion material 5 in the conversion layer is also in this embodiment, a partial conversion, ie the generation of mixed light from primary radiation 2 and secondary radiation 3 , possible.

The 4 a schematic side view of another embodiment of the radiation-emitting device 1 , The radiation-emitting device 1 includes a housing 10 with bevelled inner walls 15 , The surface of the interior walls 15 In this case, it can be coated with a reflective material, so that the radiation, which on the inner walls 15 meets up distracted. The radiation source 4 is on one of the two circuit boards 11 arranged and with a bond wire 12 electrically connected to the other circuit board. The housing 10 is with a matrix 13 poured into which the converter material 5 is embedded.

The 5 shows two emission spectra I and II in which each of the relative intensity (I _r ) of the emission of two differently processed chloroaluminate phosphors is plotted against the wavelength (λ) in nm. The excitation of the phosphor in this case was carried out with a radiation of the wavelength of 360 nm. Shown is an emission wavelength range of 450 nm to 800 nm for each emitted by the phosphor radiation. Spectrum I shows the spectrum of the chloroaluminate compound Sr _2.9 Eu _0.1 Al ₂ O ₅ Cl ₂ . This sample was prepared by annealing for 8 hours at 1250 ° C and is almost phase pure. Curve II shows the spectrum of a chloroaluminate compound which was processed at 1250 ° C for 4 hours. This sample still has 10 to 20% foreign phases (Sr ₁₂ Al ₁₄ O ₃₃ , SrCl ₂ ).

As in 5 can be seen, the emission spectrum I in the illustrated wavelength range, a higher relative intensity (I _r ), as the emission spectrum II, which still has foreign phase components.

6 shows two spectra I and II in which the reflectivity (R) against the wavelength (λ) in nm is plotted. In this experiment, the wavelength at which the phosphor is irradiated was varied from 300 nm to 800 nm, and the respective reflectivity for the corresponding wavelength was measured relative to corresponding values of a white standard with ~ 100% reflectivity. The measured samples of spectra I and II correspond to those in 5 for the corresponding emission spectra I and II measured substances.

As in 6 can be seen, the chloroaluminate compound Sr _2.9 Eu _0.1 Al ₂ O ₅ Cl ₂ below 400 nm has a low reflectivity and thus a high absorption. In the range of 400 to 430 nm, the compound also has a significant absorption capacity. By contrast, the sample with the foreign phase fractions of 10 to 20 percent has a significantly higher reflectivity, as shown in Spectrum II.

In the following, a variant of the production process for Sr _3-x Eu _x Al ₂ O ₅ Cl _{2 will be} described.

In this variant, the starting powders are weighed in the following ratios: 1.9 mol SrCO ₃ , 1 mol SrCl ₂ × 6 H ₂ O, 1 mol Al ₂ O ₃ and 0.05 mol Eu ₂ O ₃ . The powder mixture is homogenized and then annealed in a corundum boat with lid at a temperature between 1000 ° C and 1400 ° C, preferably between 1100 ° C and 1300 ° C, for 12 hours in the Formiergasstrom. The result is a powder having the following composition: Sr _2.9 Eu _0.1 Al ₂ O ₅ Cl ₂ . The resulting powder can be excited with 366 nm electromagnetic radiation to emit white-orange light.

The The invention is not by the description based on the embodiments limited. Rather, the invention includes every new feature as well any combination of features, especially any combination includes features in the claims, also if this feature or combination itself is not explicit specified in the patent claims or exemplary embodiments is.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102009022561 [0001]

Claims (15)

Chloroaluminate compound according to the general formula: Me ¹ _3-xy Eu _x Mn _y Al ₂ O ₅ Cl ₂ where Me ^{1 represents} at least one element selected from: Mg, Ca, Sr, Ba, or any combination thereof, and 0 <x <3; 0 ≤ y <3; x + y <3. A chloroaluminate compound according to claim 1, wherein Me ^{1 is} the following partial formula: (Sr _1-z Me ² _z ) resulting in the following formula: (Sr _1-z Me ² _z ) _3-xy Eu _x Mn _y Al ₂ O ₅ Cl ₂ where Me ² for at least one element is selected from: Mg, Ca, Ba and 0 ≤ z <1. A chloroaluminate compound according to any one of the preceding claims, according to the general formula: Sr _3-x Eu _x Al ₂ O ₅ Cl ₂ . Chloroaluminate compound according to one of the preceding Claims, where: 0.015 ≤ x ≤ 0.3. Radiation-emitting device ( 1 ), comprising: - a radiation source ( 4 ), which is a primary radiation ( 2 ), - a conversion material ( 5 ), in the beam path of the radiation source ( 4 ), wherein the conversion material ( 5 ) comprises a compound according to any one of claims 1 to 3, and at least a part of the primary radiation ( 2 ) by the conversion material ( 5 ) into a secondary radiation ( 3 ) is converted. Radiation-emitting device ( 1 ) according to claim 5, wherein the radiation source ( 4 ) a primary radiation ( 2 ) in a wavelength range of 180 nm to 470 nm Radiation-emitting device ( 1 ) according to one of claims 5 or 6, wherein the conversion material ( 5 ) the primary radiation ( 2 ) in secondary radiation ( 3 ), which ranges in the visible spectral range from a wavelength of 450 nm to 780 nm. Radiation-emitting device ( 1 ) according to claim 7, wherein the spectrum of the secondary radiation ( 3 ) has an intensity maximum in the wavelength range from 600 nm to 630 nm. Radiation-emitting device ( 1 ) according to one of claims 5 to 8, wherein the conversion material ( 5 ) with respect to a primary radiation ( 2 ) has a reflectivity of less than 30% from the wavelength range of 180 nm to 420 nm. Radiation-emitting device ( 1 ) according to one of claims 5 to 9, which is a mixed light ( 6 ) from the primary radiation ( 2 ) and the secondary radiation ( 3 ) emitted. Radiation-emitting device ( 1 ) according to one of claims 4 to 10, wherein the radiation source ( 4 ) comprises a semiconductor diode. A process for preparing a chloroaluminate compound according to any one of claims 1 to 4, comprising the process steps: A) providing a powder mixture comprising in each case a stoichiometric amount of Me ¹ CO ₃ and Me ¹ Cl ₂ , Al ₂ O ₃ , Eu ₂ O ₃ , B) homogenizing the powder mixture from A), C) annealing the powder mixture from B). The method of claim 12, wherein the powder mixture in step A) additionally comprises MnO ₂ . Method according to one of claims 12 or 13, wherein the annealing in step C) at a temperature takes place, which in the temperature range of 1000 ° C to 1400 ° C. lies. Method for producing a radiation-emitting device ( 1 ) according to one of claims 5 to 11, comprising the method steps: a) providing a radiation source ( 4 ), which is a primary radiation ( 2 ), b) introducing a conversion material ( 5 ) into a matrix material ( 13 ), c) introducing the matrix material ( 13 ), which the conversion material ( 5 ) in the beam path of the radiation source ( 4 ), so that at least a part of the primary radiation ( 2 ) by the conversion material ( 5 ) into a secondary radiation ( 3 ), where for the conversion material ( 5 ) a material is used which comprises a compound according to one of claims 1 to 3.