JP6947643B2 - Color-stable red-emitting phosphor - Google Patents

Description

The present invention relates to a color-stable red-emitting phosphor.

^{Activated with Mn 4+} , as described in US Pat. Nos. 7,358,542, US Pat. No. 7,497,973 and US Pat. No. 7,648,649. Red light emitting phosphors based on the complex fluoride material are produced from current fluorescent lamps, incandescent lamps and halogen lamps from blue LEDs in combination with yellow / green light emitting phosphors such as YAG: Ce. It is possible to obtain warm white light (CCT <5000K, color tone index (CRI)> 80 in the black body locus) equivalent to that of the above. These materials strongly absorb blue light, emit light efficiently in the range of about 610 nm to 658 nm, and emit little deep red / NIR light. Therefore, the luminous efficiency is maximized as compared with the red phosphor, which emits a lot of deep red with low eye sensitivity. Quantum efficiency can exceed 85% under blue (440-460 nm) excitation. In addition, the use of red phosphors for displays can result in high color gamut and efficiency.

The methods of preparing the materials described in the patent and scientific literature typically involve mixing the raw materials and precipitating the product. Some examples of such batch processes are described in Paulusz, A. et al. G. , J. Electrochem. Soc. , 942-947 (1973), US Pat. No. 7,497,973 and US Pat. No. 8,491,816. However, product scale-up issues and inter-batch variability in their properties can be major issues. In addition, the batch process produces materials with a wide range of particle sizes, including relatively large particles. Large particles can clog the distributor and cause problems in the manufacture of LED packages, making them more likely to settle unevenly, resulting in a non-uniform distribution. Therefore, a product with a smaller median particle size and a narrower particle size distribution can be obtained, and the final properties of the product can be better controlled while maintaining performance in lighting and display applications. The preparation method is desirable.

U.S. Patent Application Publication No. 2015/035453A1

Briefly, in one aspect, the invention gradually adds a first solution containing the M source and HF and a second solution containing the Mn source to the reactor in the presence of the A source to Mn ^+. The present invention relates to a method for synthesizing a ^{Mn 4+ -doped phosphor by a step of forming a product solution containing a 4-} doped phosphor; and a step of periodically discharging the product solution from the reactor.

The Mn ⁴⁺ doped phosphor may be of formula I A _x [MF _y ]: Mn ^{+ 4} I
(During the ceremony,
A is Li, Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;
x is the absolute value of the charge of the _{[MF y] ion;}
y is 5, 6 or 7;
Alternatively, this fluorophore may be selected from those having the formulas (A)-(H) (A) A ₂ [MF ₅ ]: Mn ⁴⁺ (in the formula, A is Li, Na, K, Rb). , Cs, NH ₄ and combinations thereof, M is selected from Al, Ga, In and combinations thereof);
(B) A ₃ [MF ₆ ]: Mn ⁴⁺ (In the formula, A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof; M is Al, Ga, In and them. (Selected from the combination of);
(C) Zn ₂ [MF ₇ ]: Mn ⁴⁺ (In the formula, M is selected from Al, Ga, In and combinations thereof);
(D) A [In ₂ F ₇ ]: Mn ⁴⁺ (in the formula, A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof);
(E) A ₂ [MF ₆ ]: Mn ⁴⁺ (In the formula, A is selected from Li, Na, K, Rb, Cs, NH ₄ and combinations thereof, and M is Ge, Si, Sn, Ti. , Zr, and combinations thereof);
(F) E [MF ₆ ]: Mn ⁴⁺ (In the formula, E is selected from Mg, Ca, Sr, Ba, Zn and combinations thereof, and M is Ge, Si, Sn, Ti, Zr and them. (Selected from the combination of);
(G) Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ ; and (H) A ₃ [ZrF ₇ ]: Mn ⁴⁺ (In the formula, A is selected from Li, Na, K, Rb, Cs, NH _4). NS).

In another aspect, the invention relates to Mn ⁴⁺ doped fluorophore prepared by this method.

These features, aspects, and advantages of the present invention, as well as other features, aspects, and advantages, are believed to be better understood by reviewing the following detailed description with reference to the accompanying drawings. In the accompanying drawings, similar letters represent similar parts throughout the drawing.

It is the schematic sectional drawing of the lighting apparatus by one Embodiment of this invention. It is the schematic sectional drawing of the lighting apparatus by another embodiment of this invention. It is the schematic sectional drawing of the lighting apparatus according to still another embodiment of this invention. It is a side sectional perspective view of the lighting apparatus according to one Embodiment of this invention. It is a schematic perspective view of the surface mount type device (SMD) backlight LED.

The Mn ⁴⁺ doped phosphors described herein are complex husks containing at least one coordination center surrounded by fluoride ions acting as ligands and optionally counterion charged. It is a fluoride material or a coordination compound. For example, K ₂ SiF ₆ : Mn ⁴⁺ has a coordination center of Si and a counterion of K. The complex fluoride is sometimes expressed as a combination of simple binary fluorides, but such an expression does not indicate the coordination number of the ligand around the coordination center. Square brackets (which may be omitted for simplicity) indicate that the complex ions they contain are new species that differ from simple fluoride ions. The activator ion (Mn ⁴⁺ ) also acts as a coordination center, substituting a portion of the center of the host lattice, such as Si. The host lattice (including counterions) can further modify the excitation and luminescence properties of activator ions.

In certain embodiments, the coordination center of the fluorophore, i.e. M in formula I, is Si, Ge, Sn, Ti, Zr, or a combination thereof. More specifically, the coordination center is Si, Ge, Ti or a combination thereof, A in the counterion or formula I is Na, K, Rb, Cs, or a combination thereof, y is 6 Is. Examples of phosphors of formula I are K ₂ [SiF ₆ ]: Mn ⁴⁺ , K ₂ [TiF ₆ ]: Mn ⁴⁺ , K ₂ [SnF ₆ ]: Mn ⁴⁺ , Cs ₂ [TiF ₆ ], Rb ₂ [TiF ₆ ], Cs ₂ [SiF ₆ ], Rb ₂ [SiF ₆ ], Na ₂ [TiF ₆ ]: Mn ⁴⁺ , Na ₂ [ZrF ₆ ]: Mn ⁴⁺ , K ₃ [ZrF ₇ ]: Mn ⁴⁺ , K ₃ [BiF ₆ ]: Mn ⁴⁺ , K ₃ [YF ₆ ]: Mn ⁴⁺ , K ₃ [LaF ₆ ]: Mn ⁴⁺ , K ₃ [GdF ₆ ]: Mn ⁴⁺ , K ₃ [NbF ₇ ]: Mn ⁴⁺ , K ₃ [TaF ₇ ]: Mn ⁴⁺ . In certain embodiments, the fluorophore of formula I is K ₂ SiF ₆ : Mn ⁴⁺ .

The amount of manganese in the Mn ⁴⁺ doped phosphor of Formula I can range from about 1.2 mol% (about 0.3 wt%) to about 16.5 mol% (about 4 wt%). In certain embodiments, the amount of manganese is from about 2 mol% (about 0.5 wt%) to 13.4 mol% (about 3.3 wt%), or from about 2 mol% to 12.2 mol% (about 3 wt%), or. About 2 mol% to 11.2 mol% (about 2.76 wt%), or about 2 mol% to about 10 mol% (about 2.5 wt%), or about 2 mol% to 5.5 mol% (about 1.4 wt%), or It can be from about 2 mol% to about 3.0 mol% (about 0.75 wt%).

The method according to the present invention is to gradually add a first solution containing an aqueous HF and M source and a second solution containing an Mn source to the reactor in the presence of the A source and Mn ⁴⁺ dope of formula I. It includes the step of forming a product solution containing a phosphor; and the step of periodically discharging the product solution from the reactor. The feed solution includes at least the first and second solutions as well as other solutions that can be added to the reactor before or during discharge. The method according to the present invention is to gradually add the product solution from the reactor while gradually adding the first solution containing the aqueous HF and M sources and the second solution containing the Mn source to the reactor in the presence of the A source. Including the step of discharging to. Discharge of at least a portion of the product liquid occurs at the same time as the addition of the first and second solutions. The volume of the product in the reactor is maintained at equilibrium levels by draining the product at about the same rate as adding the feed solution to the reactor. The feed solution includes at least the first and second solutions as well as other solutions that can be added to the reactor before or during discharge.

In some embodiments, the feed solution may be added to the reactor during the initial period without draining the product. In some embodiments, the reactor may be preloaded with a material selected from ^{HF, A source, Mn + 4 doped phosphor preform particles, or a combination thereof.} Non-solvent or reverse solvent for the fluorophore product can also be included in the preloading. Suitable substances for the reverse solvent include acetone, acetic acid, isopropanol, ethanol, methanol, acetonitrile, dimethylformamide, or a combination thereof. Alternatively, the antisolvent may be contained in any of the feed solutions, or in a separate feed solution that does not contain an M or Mn source, particularly a feed solution that contains an A source and does not contain an M or Mn source. ..

After the initial period, at least part of the product is drained. In some embodiments, it may be desirable to stop the addition during the discharge period, but the feed solution may continue to be added while the product is being discharged. The length of each addition period before or between efflux events typically ranges from 2 to 30 minutes, especially 5 to 15 minutes, more specifically 8 to 12 minutes. The longer the addition period, the larger the particles and / or the decomposition of the product, which can result in the loss of desired properties such as brightness. The total reaction time, i.e. the overall length of the long addition period, is not important. In some embodiments, it may be about 1 hour.

The first solution contains an aqueous HF and M source. The M source is a Si-containing compound with good solubility in solution, such as H ₂ SiF ₆ , Na ₂ SiF ₆ , (NH ₄ ) ₂ SiF ₆ , Rb ₂ SiF ₆ , Cs ₂ SiF ₆ , SiO ₂ or a combination thereof. In particular, it can be _{H 2} SiF _6. The use of H ₂ SiF ₆ is advantageous because it is highly soluble in water and does not contain alkali metal elements as impurities. The M source may be a single compound or a combination of two or more compounds. The HF concentration in the first solution may be at least 25 wt%, particularly at least 30 wt%, and more specifically at least 35 wt%. Water can be added to the first solution to reduce the concentration of HF, reduce the particle size and improve the yield of the product. The concentration of the material used as the M source may be ≦ 25 wt%, especially ≦ 15 wt%.

The second solution contains a Mn source and can also contain aqueous HF as a solvent. Materials suitable for use as a Mn source include, for example, K ₂ MnF ₆ , KMnO ₄ , K ₂ MnCl ₆ , MnF ₄ , MnF ₃ , MnF ₂ , MnO ₂ , and combinations thereof, particularly K ₂ MnF _6. Can be mentioned. The concentration of one or more compounds used as the Mn source is not important and is typically limited by its solubility in solution. The HF concentration in the second solution may be at least 20 wt%, especially at least 40 wt%.

The first and second solutions are added to the reactor in the presence of source A with stirring of the product. The amount of raw material used generally corresponds to the desired composition, except that an excess of A source may be present. The flow rate can be adjusted so that the M source and the Mn source are added in a substantially stoichiometric ratio and the A source is added in excess of the stoichiometric amount. In many embodiments, the A source is added in an amount in the range of about 150% to 300% molar excess, particularly about 175% to 300% molar excess. For example, in Mn-doped K ₂ SiF ₆ , the stoichiometric amount of K required is 2 mol / mol Mn-doped K ₂ SiF ₆ , and the amount of KF or KHF ₂ used is phosphor formation. It ranges from about 3.5 mol to about 6 mol of the object.

Source A may be a single compound or a mixture of two or more compounds. Suitable materials include KF, KHF ₂ , KOH, KCl, KBr, Kl, KOCH ₃ or K ₂ CO ₃ , especially KF and KHF ₂ , and more particularly KHF ₂ . The K-containing Mn source, such as _{K 2} MnF ₆ , may be a K source specifically in combination with _{KF or KHF 2.} Source A may be present in either or both of the first and second solutions, in a third solution added separately, in a reactor pot, or in one or more combinations thereof. You may.

After the product has been expelled from the reactor, the Mn ^{+ 4-} doped phosphor is isolated from the product by simply decanting the solvent or by filtration, US Pat. No. 8,252,613 or As described in U.S. Patent Application No. 2015/0054400, compounds of formula II;
A ¹ _x [MF _y ]
II
(During the ceremony,
A ¹ is H, Li, Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof, and x is the absolute value of the charge of the _{[MF y] ion.} And
y is 5, 6 or 7)
Can be treated with a concentrated solution in aqueous hydrofluoric acid.

_{The compound of formula II comprises at least the MF y} anion of the host compound for the fluorophore product and can also include ^{the A +} cation of the compound of formula I. For the phosphor product of formula Mn-doped K ₂ SiF _{6 , H 2} SiF ₆ , Na ₂ SiF ₆ , (NH ₄ ) ₂ SiF ₆ , Rb ₂ SiF ₆ , Cs ₂ are suitable materials for the compound of formula II. Included is SiF ₆ , or a combination thereof, in particular H ₂ SiF ₆ , K ₂ SiF ₆ and combinations thereof, and more particularly K ₂ SiF ₆ . The treatment solution is a saturated or nearly saturated solution of the compound of formula II in hydrofluoric acid. The nearly saturated solution contains about 1-10% excess aqueous HF added to the saturated solution. The concentration of HF in the solution ranges from about 25% (wt / vol) to about 70% (wt / vol), especially from about 40% (wt / vol) to about 50% (wt / vol). Low concentration solutions may reduce the performance of the phosphor. The amount of treatment solution used is in the range of about 2-30 ml / g product, particularly about 5-20 ml / g product, more specifically about 5-15 ml / g product.

The treated fluorophore can be vacuum filtered and washed with one or more solvents to remove HF and unreacted feedstock. Suitable materials for cleaning solvents include acetic acid and acetone, and combinations thereof.

Span is a measure of the width of the particle size distribution curve for particulate matter or powder and is defined according to equation (1):

（１）
式中、
Ｄ₅₀は体積分布のメジアン粒径であり、
Ｄ₉₀は、分布の粒子の９０％の粒径よりも大きい体積分布の粒径であり、
Ｄ₁₀は、分布の粒子の１０％の粒径よりも大きい体積分布の粒径である。

(1)
During the ceremony
D ₅₀ is the median particle size of the volume distribution,
D ₉₀ is a volume distribution particle size larger than 90% particle size of the distributed particles.
D ₁₀ is the particle size of the volume distribution larger than the particle size of 10% of the distributed particles.

The particle size of the phosphor powder can be conveniently measured by laser diffraction _{, and software on the market can be used to create spans of D 90} , D ₁₀ , and D ₅₀ particle size values and distributions. Can be done. In the case of the phosphor particles of the present invention, the D ₅₀ particle size ranges from about 10 μm to about 40 μm, particularly from about 15 μm to about 35 μm, and more specifically from about 20 μm to about 30 μm. The span of the particle size distribution can be ≤1.0, particularly ≤0.9, more specifically ≤0.8, and even more specifically ≤0.7. The particle size can be controlled by adjusting the flow rate, reactant concentration, and equilibrium volume of the product.

The fluorophore product can be isolated from the product, treated, dried and then annealed to improve stability as described in US Pat. No. 8,906,724. In such an embodiment, the fluorophore product is retained at elevated temperature while in contact with an atmosphere containing a fluorine-containing oxidant. Fluorine-containing oxidizing agents include F ₂ , HF, SF ₆ , BrF ₅ , NH ₄ HF ₂ , NH ₄ F, KF, AlF ₃ , SbF ₅ , ClF ₃ , BrF ₃ , KrF ₂ , XeF ₂ , XeF ₄ , NF ₃ , SiF ₄ , PbF ₂ , ZnF ₂ , SnF ₂ , CdF ₂ or a combination thereof can be mentioned. In certain embodiments, the fluorine-containing oxidant is F ₂ . Color-stable phosphors can be obtained by varying the amount of oxidant in the atmosphere, especially with changes in time and temperature. When the fluorinated oxidant is F ₂ , the atmosphere can contain at least 0.5% F ₂ , but lower concentrations may be effective in some embodiments. In particular, the atmosphere can include at least 5% F ₂ and more specifically at least 20% F ₂ . The atmosphere can further include nitrogen, helium, neon, argon, krypton, xenon in any combination with a fluorine-containing oxidant. In certain embodiments, the atmosphere is _{composed of about 20% F 2} and about 80% nitrogen.

The temperature at which the phosphor contacts the fluorine-containing oxidant is any temperature in the range of about 200 ° C to about 700 ° C, particularly about 350 ° C to about 600 ° C during contact, and in some embodiments about 500. ° C to about 600 ° C. The fluorophore is contacted with an oxidant for a time sufficient to convert it into a color-stable fluorophore. Time and temperature are interrelated and can be adjusted together, for example, by lowering the temperature to increase the time, or by shortening the time and increasing the temperature. In certain embodiments, the time is at least 1 hour, particularly at least 4 hours, more specifically at least 6 hours, and most specifically at least 8 hours.

After holding for a desired time in the temperature rise, the temperature in the furnace can be lowered at a controlled rate while maintaining an oxidizing atmosphere during the initial cooling period. After the initial cooling period, the cooling rate may or may not be controlled at the same or different rates. In some embodiments, the cooling rate is controlled until a temperature of at least 200 ° C. is reached. In other embodiments, the cooling rate is controlled at least until it reaches a temperature safe to purge the atmosphere. For example, the temperature can be lowered to about 50 ° C. and then the purging of the fluorine atmosphere can be started. When the temperature is lowered at a controlled rate of 5 ° C./min or less, a phosphor product having excellent properties can be obtained as compared with the case where the temperature is lowered at a rate of 10 ° C./min. In various embodiments, this rate can be controlled at a rate of 5 ° C./min or less, particularly 3 ° C./min or less, and more specifically 1 ° C./min or less.

The duration of temperature reduction at a controlled rate is related to contact temperature and cooling rate. For example, when the contact temperature is 540 ° C. and the cooling rate is 10 ° C./min, the period for controlling the cooling rate is less than 1 hour, after which the temperature may be reduced to purge temperature or ambient temperature without external control. When the contact temperature is 540 ° C. and the cooling rate is 5 ° C./min or less, the cooling time can be less than 2 hours. When the contact temperature is 540 ° C. and the cooling rate is 3 ° C./min or less, the cooling time can be less than 3 hours. When the contact temperature is 540 ° C. and the cooling rate is 1 ° C./min or less, the cooling time can be less than 4 hours. For example, controlled cooling can reduce the temperature to about 200 ° C. and then discontinue control. After a controlled cooling period, the temperature may drop at a higher or lower rate than the initial controlled rate.

The mode in which the fluorophore is brought into contact with the fluorine-containing oxidant is not important and can be achieved in any way sufficient to convert the fluorophore into a color-stable fluorophore with the desired properties. In some embodiments, the chamber containing the phosphor is added so that overpressure occurs when the chamber is heated and then sealed, and in other embodiments a mixture of fluorine and nitrogen is annealed throughout the process. Flow through to ensure a more uniform pressure. In some embodiments, the addition of an additional fluorine-containing oxidant may be introduced after a period of time.

The annealed fluorophore can be treated with a saturated or nearly saturated solution of the composition of formula II in aqueous hydrofluoric acid, as described in US Pat. No. 8,252,613. The amount of treatment solution used is in the range of about 10 ml / g product to 20 ml / g product, especially about 10 ml / g product. The treated annealed fluorophore is isolated by filtration and washed with solvents such as acetic acid and acetone to remove contaminants and trace amounts of water and can be stored under nitrogen.

All of the numbers described herein are all values from low to high in 1 unit increments if there is at least 2 units of separation between any low and any high values. including. As an example, if the amount of component or the value of a process variable such as temperature, pressure, time is stated to be, for example, 1-90, preferably 20-80, more preferably 30-70, 15-5. It is intended that values such as 85, 22-68, 43-51, 30-32, etc. are explicitly listed herein. For values less than 1, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate. These are only specifically intended examples and all possible combinations of numbers between the listed minimum and maximum values are considered to be explicitly stated in a similar manner in this application. Should be.

A lighting device or light emitting assembly or lamp 10 according to an embodiment of the present invention is shown in FIG. The illuminator 10 includes a semiconductor radiation source, represented as a light emitting diode (LED) chip 12, and a lead 14 electrically attached to the LED chip. The lead 14 may be a thin wire supported by one or more thicker lead frames 16, or the lead may be a self-supporting electrode and the lead frame may be omitted. The lead 14 supplies an electric current to the LED chip 12, thereby emitting radiation.

The lamp can include a semiconductor blue or UV light source capable of producing white light when the emitted radiation is directed at the phosphor. In one embodiment, the semiconductor light source is a blue light emitting LED doped with various impurities. Therefore, LEDs can include semiconductor diodes having emission wavelengths of about 250-550 nm, based on any suitable III-V, II-VI or IV-IV semiconductor layer. In particular, the LED can include at least one semiconductor layer containing GaN, ZnSe or SiC. _{For example, LEDs are represented by the formula In i} Ga _j Al _k N (in the formula, 0 ≦ i; 0 ≦ j; 0 ≦ k and I + j + k = 1) having emission wavelengths longer than about 250 nm and shorter than about 550 nm. The nitride compound semiconductor to be used can be included. In certain embodiments, the chip is a near-ultraviolet or blue light emitting LED having a peak emission wavelength of about 400 to about 500 nm. Such LED semiconductors are known in the art. The source of radiation is referred to herein as an LED for convenience. However, as used herein, the term is meant to include all semiconductor sources, including, for example, semiconductor laser diodes. Moreover, although the general discussion of the exemplary structures of the invention discussed herein is intended for inorganic LED-based light sources, unless otherwise specified, LED chips can be replaced with another source of radiation, such as semiconductors. References to semiconductor LEDs, or LED chips, should be understood as merely representative examples of any suitable light source, including, but not limited to, organic light emitting diodes.

In the illuminating device 10, the phosphor composition 22 is radiatively coupled to the LED chip 12. Radiation coupling means that radiation from one is transmitted to the other because the elements are related to each other. The fluorescent composition 22 is deposited on the LED 12 by any suitable method. For example, a water-based suspension of one or more phosphors can be formed and applied to the LED surface as a phosphor layer. In one such method, a silicone slurry in which phosphor particles are randomly suspended is placed around the LED. This method is merely an example of possible locations of the fluorescent composition 22 and the LED 12. Therefore, the fluorescent composition 22 can be coated on or directly on the light emitting surface of the LED chip 12 by coating the fluorescent suspension on the LED chip 12 and drying it. For silicone-based suspensions, this suspension is cured at a suitable temperature. Both the shell 18 and the encapsulant 20 must be transparent so that the white light 24 can pass through these elements. Although not intended to be limiting, in some embodiments, the median particle size of the fluorescent composition is in the range of about 1 to about 50 microns, especially about 15 to about 35 microns.

In another embodiment, the fluorescent composition 22 is interspersed within the encapsulant 20 instead of being formed directly on the LED chip 12. Fluorescent materials (powder form) can be interspersed within a single region of encapsulant 20 or over the entire volume of encapsulant. The blue light emitted by the LED chip 12 mixes with the light emitted by the phosphor composition 22, and the mixed light appears as white light. When the fluorescent materials are scattered in the encapsulant 20, the fluorescent material powder is added to the polymer or silicone precursor loaded around the LED chip 12, and then the polymer precursor is cured to solidify the polymer or silicone material. can do. Other known phosphor interspersed methods, such as transfer loading, can also be used.

In some embodiments, the encapsulant 20 is a silicone matrix having a refractive index R, and in addition to the phosphor composition 22, a diluent having an absorbance of less than about 5% and a refractive index of R ± 0.1. including. The diluent has a refractive index of ≤1.7, particularly ≤1.6 and more specifically ≤1.5. In certain embodiments, the diluent is of formula II and has a refractive index of about 1.4. The addition of an optically inert material to the fluorophore / silicone mixture results in a more gradual distribution of luminous flux through the fluorophore / encapsulant mixture, which can reduce damage to the fluorophore. Suitable materials for diluent _{include LiF, MgF 2} , CaF ₂ , SrF ₂ , AlF having a refractive index in the range of _{about 1.38 (AlF 3} and K ₂ NaAlF ₆ ) to about 1.43 (CaF _{2). 3,} K ₂ NaAlF _6, is _{KMgF 3, CaLiAlF 6, K 2} LiAlF 6, and fluoride compounds as well as polymers having a refractive index of about 1.254～ about 1.7 range, such as K ₂ SiF ₆ and the like .. Non-limiting examples of polymers suitable for use as diluents include polycarbonate, polyester, nylon, polyetherimide, polyetherketone, and styrene, acrylate, methacrylate, vinyl, vinyl acetate, ethylene, propylene oxide and ethylene oxide. Polymers derived from monomers and copolymers thereof are mentioned, and halogenated and non-halogenated derivatives are mentioned. These polymer powders can be incorporated directly into the silicone encapsulant and then the silicone can be cured.

In yet another embodiment, the fluorescent composition 22 is coated on the surface of the shell 18 instead of being formed over the LED chips 12. The fluorescent composition is preferably coated on the inner surface of the shell 18, but may be coated on the outer surface of the shell if desired. The fluorescent composition 22 may be coated on the entire surface of the shell, or may be coated only on the upper surface of the shell. The UV / blue light emitted by the LED chip 12 mixes with the light emitted by the phosphor composition 22, and the mixed light appears as white light. Of course, the fluorophore can be placed in any two or all three locations, or in any other suitable location, such as separately from the shell or integrated with the LED.

FIG. 2 illustrates a second structure of the system according to the present invention. Corresponding numbers in FIGS. 1 to 4 (eg, 12 in FIG. 1 and 112 in FIG. 2) relate to the corresponding structure in each figure unless otherwise specified. The structure of the embodiment of FIG. 2 is similar to that of FIG. 1 except that the fluorescent composition 122 is scattered in the encapsulant 120 instead of being formed directly on the LED chip 112. The fluorophore (powder form) can be interspersed within a single region of the encapsulant or over the entire volume of the encapsulant. The radiation emitted by the LED chip 112 (indicated by arrow 126) mixes with the light emitted by the phosphor 122, and the mixed light appears as white light 124. When the fluorophore is interspersed within the encapsulant 120, the fluorophore powder can be added to the polymer precursor and loaded around the LED chip 112. The polymer or silicone precursor can then be cured to solidify the polymer or silicone. Other known phosphor interspersed methods, such as transfer molding, can also be used.

FIG. 3 illustrates a third possible structure of the system according to the invention. The structure of the embodiment shown in FIG. 3 is similar to that of FIG. 1 except that the fluorescent composition 222 is coated on the surface of the envelope 218 instead of being formed over the LED chip 212. The fluorescent composition 222 is preferably coated on the inner surface of the envelope 218, but may be coated on the outer surface of the envelope if desired. The fluorescent composition 222 may be coated on the entire surface of the envelope, or may be coated only on the upper surface of the envelope. The radiation 226 emitted by the LED chip 212 mixes with the light emitted by the phosphor composition 222, and the mixed light appears as white light 224. Of course, the structures of FIGS. 1 to 3 can be combined and the fluorophore can be placed in any two or all three locations, or separately from the envelope or integrated into the LED. It can be placed elsewhere as appropriate.

In any of the above structures, the lamp can include a plurality of scattered particles (not shown) embedded in the encapsulant. Examples of the scattered particles include alumina and titania. The scattered particles effectively scatter the directional light emitted from the LED chip with a preferably negligible amount of absorption.

As shown in the fourth structure of FIG. 4, the LED chip 412 may be mounted in the reflective cup 430. The cup 430 is made from or coated with a dielectric material such as alumina, titania, or other dielectric powder known in the art, or coated with a reflective metal such as aluminum or silver. May be good. The rest of the structure of the embodiment of FIG. 4 is the same as any of the structures in the previous drawings and may include two leads 416, conductors 432, and encapsulant 420. The reflective cup 430 is supported by a first lead 416, and a lead 432 is used to electrically connect the LED chip 412 to the second lead 416.

Another structure (particularly for backlight applications) is a surface mount device (“SMD”) type light emitting diode 550, for example as illustrated in FIG. This SMD is a "side light emitting type" and has a light emitting window 552 at a protruding portion of the light guide member 554. The SMD package can include the LED chip defined above and a phosphor material excited by the light emitted from the LED chip. Other backlit devices include, but are not limited to, televisions, computers, smartphones, tablet computers, and other portable devices that have a display that includes ^{a semiconductor light source and a color-stable Mn 4+ doped phosphor according to the invention.} Can be mentioned.

When used with an LED that emits light at 350-550 nm and one or more other suitable phosphors, the resulting illumination system produces light with a white color. The lamp 10 may also further include scattered particles (not shown) embedded in the encapsulant. Examples of the scattered particles include alumina and titania. The scattered particles effectively scatter the directional light emitted from the LED chip with a preferably negligible amount of absorption.

In addition to the color-stable Mn ⁴⁺ doped fluorophore, the fluorophore composition 22 can include one or more other fluorophores. When used in a luminaire in combination with a blue or near-ultraviolet LED that emits radiation in the range of about 250-550 nm, the resulting light emitted by the assembly will be white light. Other phosphors, such as green, blue, yellow, red, orange, or other colored phosphors, can be used in the blend to customize the whiteness of the resulting light and generate a particular spectral output distribution. Other materials suitable for use in the fluorescent composition 22 include polyfluorene, preferably poly (9,9-dioctylfluorene) and copolymers thereof, such as poly (9,9'-dioctylfluorene-co-bis-). N, N'-(4-butylphenyl) diphenylamine) (F8-TFB); electroluminescence polymers such as poly (vinylcarbazole) and polyphenylene vinylene and derivatives thereof. Further, the light emitting layer may contain a blue, yellow, orange, green or red phosphorescent dye or metal complex or a combination thereof. Suitable materials for use as phosphorescent dyes include, but are not limited to, tris (1-phenylisoquinolin) iridium (III) (red dye), tris (2-phenylpyridine) iridium (green dye) and Examples include iridium (III) bis (2- (4,6-difluorophenyl) pyridinato-N, C2) (blue dye). Fluorescent and phosphorescent metal complexes commercially available from ADS (American Dyes Source, Inc.) can also be used. Examples of the green dye of ADS include ADS060GE, ADS061GE, ADS063GE, and ADS066GE, ADS078GE, and ADS090GE. Examples of the blue dye of ADS include ADS064BE, ADS065BE, and ADS070BE. Examples of the red dye of ADS include ADS067RE, ADS068RE, ADS069RE, ADS075RE, ADS076RE, ADS067RE, and ADS077RE.

Suitable phosphors for use in the fluorophore composition 22 in addition to the Mn ^{4+ doped fluorophore are, but are not limited to:}
_{((Sr 1-z (Ca} , Ba, Mg, Zn) z) 1- (x + w) (Li, Na, K, Rb) w Ce x) 3 (Al 1-y Si y) O 4 + y _{+3 (xw)} F _{1-y-3 (xw)} , 0 <x≤0.10, 0≤y≤0.5, 0≤z≤0.5, 0≤w≤x; (Ca, Ce) ₃ Sc ₂ Si ₃ O ₁₂ (CaSiG); (Sr, Ca, Ba) ₃ Al _1-x Si _x O _{4 + x} F _1-x : Ce ³⁺ (SASOF)); (Ba, Sr, Ca) ₅ (PO ₄ ) ₃ (Cl, F, Br, OH): Eu ²⁺ , Mn ²⁺ ; (Ba, Sr, Ca) BPO ₅ : Eu ²⁺ , Mn ²⁺ ; (Sr, Ca) ₁₀ (PO ₄₎ ) ₆ * νB ₂ O ₃ : Eu ²⁺ (in the formula, 0 <ν ≦ 1); Sr ₂ Si ₃ O ₈ * ₂ SrCl 2: Eu ²⁺ ; (Ca, Sr, Ba) ₃ MgSi ₂ O ₈ : Eu ²⁺ , Mn ²⁺ ; BaAl ₈ O ₁₃ : Eu ²⁺ ; 2SrO * 0.84P ₂ O ₅ * 0.16B ₂ O ₃ : Eu ²⁺ ; (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu ^{2 +} , Mn ²⁺ ; (Ba, Sr, Ca) Al ₂ O ₄ : Eu ²⁺ ; (Y, Gd, Lu, Sc, La) BO ₃ : Ce ³⁺ , Tb ³⁺ ; ZnS: Cu ⁺ , Cl ^{-; ZnS: Cu +, Al} 3+; ZnS: Ag +, Cl -; ZnS: Ag +, Al 3+; (Ba, Sr, Ca) 2 Si 1- ξO 4-2 ξ: Eu 2+ ( wherein Medium, 0 ≦ ξ ≦ 0.2); (Ba, Sr, Ca) ₂ (Mg, Zn) Si ₂ O ₇ : Eu ²⁺ ; (Sr, Ca, Ba) (Al, Ga, In) ₂ S ₄ : Eu ²⁺ ; (Y, Gd, Tb, La, Sm, Pr, Lu) ₃ (Al, Ga) _5- αO _{12-3 / 2} α: Ce ³⁺ (0 ≤ α ≤ 0.5 in the formula) ); (Ca, Sr) ₈ (Mg, Zn) (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ , Mn ²⁺ ; Na ₂ Gd ₂ B ₂ O ₇ : Ce ³⁺ , Tb ³⁺ ; (Sr, Ca) , Ba, Mg, Zn) ₂ P ₂ O ₇ : Eu ²⁺ , Mn ²⁺ ; (Gd, Y, Lu, La) ₂ O ₃ : Eu ³⁺ , Bi ³⁺ ; (Gd, Y, Lu, La) ) ₂ O ₂ S: Eu ³⁺ , Bi ³⁺ ; (Gd, Y, Lu, La) VO ₄ : Eu ³⁺ , Bi ³⁺ ; (Ca, Sr) S: Eu ²⁺ , Ce ³⁺ ; SrY ₂ S ₄ : Eu ²⁺ ; CaLa ₂ S ₄ : Ce ³⁺ ; (Ba, Sr, Ca) MgP ₂ O ₇ : Eu ²⁺ , Mn ²⁺ ; (Y, Lu) ₂ WO ₆ : Eu ³⁺ , Mo ⁶⁺ ; (Ba, Sr, Ca) βSiγNμ : Eu 2+ ( wherein, 2β + 4γ = 3μ); Ca 3 (SiO 4) Cl 2: Eu 2+; (Lu, Sc, Y, Tb) 2-uv Ce v Ca 1 _{+ u} Li _w Mg _2-w P _w (Si, Ge) _3-w O _{12-u / 2} (in the formula, -0.5 ≤ u ≤ 1, 0 <v ≤ 0.1, and 0 ≤ w ≤ 0.2); (Y, Lu, Gd) _2- ψCa ψSi ₄ N ₆₊ ψC _1- ψ: Ce ³⁺ , (in the formula, 0 ≦ ψ ≦ 0.5); (Ca, Sr, Ba) SiO ₂ N ₂ : Eu ²⁺ , Ce ³⁺ ; (Lu, Ca, Li, Mg, Y) Eu ²⁺ and / or Ce ³⁺ doped α-SiAlON; β-SiAlON: Eu ²⁺ , 3.5MgO * 0.5MgF ₂ * GeO ₂ : Mn ⁴⁺ ; Ca _1-cf Ce _c Eu _f Al _{1 + c} Si _1-c N _3, (0 ≦ c ≦ 0.2, 0 ≦ f ≦ 0.2 in the formula) _{); Ca 1-hr Ce h} Eu r Al 1-h (Mg, Zn) h SiN 3, ( where, 0 ≦ h ≦ 0.2,0 ≦ r ≦ 0.2); Ca 1-2s-t _{ce s (Li, Na) s} Eu t AlSiN 3, ( where, 0 ≦ s ≦ 0.2,0 ≦ f ≦ 0.2, s + t>0); and _{Ca 1- σ - χ - φCeσ (} Li, Na) χEuφAl _{1 +} σ _- χSi _1- σ ₊ χN ₃ , (in the formula, 0 ≦ σ ≦ 0.2, 0 ≦ χ ≦ 0.4, 0 ≦ φ ≦ 0.2).

In particular, the fluorophore composition 22 can include one or more fluorophores that result in a green spectral output distribution under ultraviolet, violet, or blue excitation. In the context of the present invention, this is referred to as a green fluorophore or green fluorophore material. Green phosphors range from green to yellow-green to yellow, such as cerium-doped yttrium aluminum garnet, more specifically (Y, Gd, Lu, Tb) ₃ (Al, Ga) ₅ O ₁₂ : Ce ^3+. It may be a single composition or blend that emits light. The green fluorophore may be a blend of garnet material shifted to blue and red. For example, a Ce ^{3+ dope garnet with blue shift luminescence may be used in combination with a Ce 3+} dope garnet with red shift luminescence, resulting in a blend with a green spectral output distribution. Blue and red shifted garnets are known in the art. In some embodiments, for the baseline Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor, the blue shift garnet substitutes Lu ^{3+ for Y 3+ and} Ga ^{3 for Al 3+. It} may have a ^{+ substitution or may reduce the Ce 3+} doping level in the _{Y 3} Al ₅ O ₁₂ : Ce ³⁺ phosphor composition. The red shift garnet may have a substitution of ^{Y 3+} for Gd ³⁺ / Tb ³⁺ or may increase the ^{Ce 3+ doping level.} An example of a green phosphor that is particularly useful for display applications is β-SiAlON.

The ratio of each of the individual phosphors in the fluorophore blend can vary depending on the desired light output characteristics. The relative proportions of the individual phosphors in the fluorophore blends of the various embodiments are visible light of predetermined x and y values on the CIE chromaticity diagram when their emission is blended and used in an LED lighting device. Can be adjusted to generate. As mentioned above, white light is preferably produced. The white light can have, for example, an x value in the range of about 0.20 to about 0.55 and a y value in the range of about 0.20 to about 0.55. However, as mentioned above, the exact identity and amount of each fluorophore in the fluorophore composition can be varied according to the needs of the end user. For example, this material can be used for LEDs intended for liquid crystal display (LCD) backlights. In this application, the LED color points are properly adjusted based on the desired white, red, green, and blue after passing through the LCD / color filter combination. The list of potential fluorophores for a given blend does not mean that they are exhaustive, and these Mn ⁴⁺ doped fluorophores are blended with various fluorophores with different luminescence, The desired spectral output distribution can be achieved.

In some embodiments, the illuminator 10 has a color temperature of 4200 ° K. or less, and the phosphor composition 22 comprises a red phosphor consisting ^{of a color stable Mn 4+ doped fluorophore of formula I.} That is, only the red phosphor present in the fluorophore composition 22 is a color-stable Mn ⁴⁺ doped phosphor; in particular, the phosphor is K ₂ SiF ₆ : Mn ⁴⁺ . The composition may further comprise a green fluorophore. The green phosphor is a Ce ³⁺ doped garnet or garnet blend, especially a Ce ³⁺ doped yttrium aluminum garnet, more specifically the formula (Y, Gd, Lu, Tb) ₃ (Al, Ga) ₅ O ₁₂ : Ce ^3+. Can be YAG with. When the red fluorophore is K ₂ SiF ₆ : Mn ⁴⁺ , the mass ratio of the red fluorophore to the green fluorophore material can be less than 3.3, which is significantly more than a red fluorophore of similar composition. Although low, the level of Mn dopant is low.

The color-stable Mn ⁴⁺ doped fluorophore of the present invention can be used for applications other than the above. For example, the material can be used as a fluorescent lamp, cathode ray tube, plasma display device or liquid crystal display (LCD) phosphor. This material can also be used as an electromagnetic calorimeter, gamma ray camera, computed tomography scanner or laser scintillator. These uses are merely examples and are not limited.

Comparative Examples 1 and 2: ^{Preparation of Mn 4+} Dope K ₂ SiF ₆ by Batch Process Table 1 shows the amount and distribution of starting materials between beakers A and D. Beaker A was actively agitated and the contents of beaker B were added dropwise thereto over about 10 minutes. Approximately 1 minute after the start of the contents of beaker B, dropping of the contents of beakers C and D into beaker A was started and continued for about 9 minutes. The precipitate was warmed for 10 minutes and stirring was stopped. The supernatant was decanted, the precipitate was evacuated, rinsed once with acetic acid and twice with acetone, then dried under vacuum. The dry powder was sieved through a 325 mesh sieve and annealed at 540 ° C. for 8 hours under _{a 20% F 2/80% nitrogen atmosphere.} The annealed fluorophore _{was washed with a solution of 49% HF saturated with K 2} SiF ₆ , dried under vacuum and sieved through a 325 mesh sieve.

実施例１：半連続流プロセスによるＭｎ⁴⁺ドープＫ₂ＳｉＦ₆−−０．７５％Ｍｎ−−の調製
手順
反応器には最初にＨＦ中のＫＦまたは二フッ化カリウムの溶液を装填する。最初の装填にはＫ₂ＭｎＦ₆も含まれていてもよい。次いで、Ｋ₂ＳｉＦ₆およびＫ２ＭｎＦ６の別々の供給溶液を、それぞれＨＦ中で開始する。ＨＦ中のＫＦまたは二フッ化カリウム溶液は別々に供給されてもよいが、ＫＦは他の溶液または初期装填物に含まれていてもよい。約１０分後、供給液を停止し、混合物の一部を反応器から取り出す。この手順は複数回繰り返してもよい。

^{Example 1: Preparation of Mn 4+} Dope K ₂ SiF ₆ −−0.75% Mn −− by Semi-Continuous Flow Process Procedure The reactor is first loaded with a solution of KF or potassium difluoride in HF. The initial loading may also include _{K 2} MnF _6. Separate feed solutions of K ₂ SiF _{6 and K 2 MnF 6 are} then started in HF, respectively. The KF or potassium difluoride solution in HF may be supplied separately, but KF may be included in other solutions or in the initial loading. After about 10 minutes, the feed is shut down and a portion of the mixture is removed from the reactor. This procedure may be repeated multiple times.

Detailed procedure 1. Using 1.0L PTFE reactor and U-shaped impeller.

2. The reactor lid should have three holes and slots drilled for the three feed tubes so that the impeller is centered on the reactor.

3. 3. Prepare three clean, dry, 500 mL Nalgene bottles labeled with the appropriate filling volume. One bottle is labeled with the sum of the feeds for the initial reaction. The other two are the sum of the feed solutions for the second, third, and further reactions. (When the reactor is drained after each batch, 120 mL of solution remains in the reactor)
4. Prepare the feed solution according to the table below.

５．すべてのポンプを準備し、反応器の蓋にチューブを挿入する。

5. Prepare all pumps and insert the tubing into the reactor lid.

６．最初の実行のために、反応器にＫＨＦ₂（１２０ｍＬ）および０．８４ｇのＭｎを装填する。２５０ＲＰＭでスターラーをオンにして、２４．７ｍＬ／分でＳｉ供給液のみポンピングを開始する。４０秒後、１２．７ｍＬ／分に変更する。１分で、ＫＦおよびＭｎ供給液を開始する。すべての供給液を９分３０秒まで実行する。ＭｎおよびＫＦを９分３０秒で停止する。１０分でＳｉ供給液を停止する。

6. For the first run, the reactor is _{loaded with KHF 2} (120 mL) and 0.84 g Mn. Turn on the stirrer at 250 RPM and start pumping only the Si feed at 24.7 mL / min. After 40 seconds, change to 12.7 mL / min. In 1 minute, the KF and Mn feeds are started. Run all feeds for up to 9 minutes and 30 seconds. Mn and KF are stopped at 9 minutes and 30 seconds. The Si supply liquid is stopped in 10 minutes.

7. When all feeds are shut down, drain the reactor into a Nalgene bottle so that only 120 mL remains in the reactor (drain 218 mL). Cap the bottle and set it aside.

8. The speed of the Si and Mn feeds for the second reaction is changed. Start all feeds and run for 12 minutes. After 10 minutes, the discharge procedure is repeated (discharge 290 mL). Save for batches 3 and 4 and repeat.

9. Filtration is initiated by decanting the PFS and pouring it into the filter while batch 4 is running. Filter the three batches together. Rinse until pH is 5.5, set aside, dry and sieve.

10. One of the bottles of batch 2 or 3 is used to eject batch 4, set aside, and the other bottle is used to run and eject batch 5. Batches 4 and 5 are filtered together while the sixth batch is running. Wash and save.

11. After stopping the pump in the 6th batch, prepare the funnel and drain the reactor completely. Rinse others as well.

12. All powders are sieved through a 325 mesh sieve.

Examples 2 to 3: Preparation of Mn ⁴⁺ Dope K ₂ SiF ₆ −−0.75% and 1.35% Mn −− by Semi-Continuous Flow Process The procedure of Example 1 was repeated for Examples 2 and 3. The same amount of raw material was used in Example 2: For Example 3, the amount of Mn was increased proportionally to give about 1.35% Mn in the fluorophore product. Table 2 shows the results including the particle size distribution data of the obtained phosphor.

比較例１および２では、３２５シーブの開口よりも大きい粒子を有する材料の量が比較的多かったことが分かる。対照的に、実施例１から３の蛍光体では、特大粒子の量が大幅に減少した。

It can be seen that in Comparative Examples 1 and 2, the amount of material having particles larger than the opening of 325 sheaves was relatively large. In contrast, in the fluorophores of Examples 1 to 3, the amount of oversized particles was significantly reduced.

Although only a few particular features of the invention have been exemplified and described herein, many modifications and modifications will come to those skilled in the art. Therefore, it should be understood that the appended claims are intended to include all such modifications and modifications as being within the scope of the true spirit of the invention.

10 Lighting device, lamp 12 LED chip, LED
14 Lead 16 Lead frame 18 Shell 20 Encapsulant 22 Fluorescent composition 24 White light 112 LED chip 120 Encapsulant 122 Fluorescent composition 124 White light 126 Radiation 212 LED chip 218 Envelope 222 Fluorescent composition 224 White light 226 Radiation 4 12 LED chip 416 1st lead, 2nd lead 420 Encapsulant 430 Reflection cup 432 Lead wire 550 Light emitting diode 552 Light emitting window 554 Light guide member

Claims (9)

A method for preparing a ^{Mn 4+} doped fluorophore of formula I.
K x [ Si Fy]: Mn ⁴⁺
I
In the method, a first solution containing a Si source and an HF and a second solution containing an Mn source are gradually added to the reactor in the presence of a K source, and a product solution containing the ^{Mn 4 + doped phosphor is contained.} Steps to form,
A step of periodically draining at least a part of the product in the reactor.
The Mn ⁴⁺ doped step phosphor isolated from the product solution, and the Mn ⁴⁺ doped phosphor is contacted with a gaseous fluorine-containing oxidizing agent in the temperature of the, form a color-stable Mn ⁴⁺ doped phosphors of the formula I How to include steps to do;
(During the ceremony,
x is the absolute value of the charge of the [Si Fy] ion.
y is 5, 6 or 7). The method of claim 1, further comprising the step of gradually adding a third solution containing the K source to the reactor. The method of claim 1, further comprising an initial period in which the first and second solutions are gradually added to the reactor without draining the product. The method of claim 1, further comprising preloading the reactor with a material selected from HF, K source, ^{preformed particles of the Mn 4+ doped fluorophore, or a combination thereof.} y is 6,
The method according to claim 1. The method of claim 1, wherein the Mn ⁴⁺ doped fluorophore of _{formula I is K 2} SiF ₆ : Mn ^4+. The method according to claim 1, wherein the fluorine-containing oxidizing agent is F _2. A method for preparing a color-stable Mn ^{4+ doped fluorophore of formula I.}
K x [ Si Fy]: Mn ⁴⁺
I
The method comprises gradual addition of a first feed solution containing an HF and Si source and a second feed solution containing an Mn source to the reactor in the presence of a K source to produce a Mn ⁴⁺ doped fluorophore. Steps to form a liquid,
A step of periodically discharging the product liquid from the reactor while the volume of the product liquid in the reactor remains constant.
A step of isolating the Mn ⁴⁺ doped phosphor from the product solution, and a step of ^{contacting the Mn 4+} doped phosphor with a fluorine gas at a temperature rise to form a ^{color-stable Mn 4+ doped phosphor of formula I.}
How to include;
(During the ceremony,
x is the absolute value of the charge of the [Si Fy] ion.
y is 5, 6 or 7). The method of claim 8 , further comprising adding a third feed solution containing a K source to the reactor.

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