JP2016160318A - Phosphor mixture, and light-emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor mixture that can produce a white LED light-emitting device achieving good luminous efficiency with high color rendering properties and suppressed color breakup.SOLUTION: The phosphor mixture contains a yellow light-emitting phosphor which is an SrSiAlONgroup crystal showing a luminescence peak in the wavelength range of 510 to 570 nm and a blue light-emitting phosphor which is an SrSiAlONgroup crystal showing a luminescence peak in the wavelength range of 430 to 500 nm, when excited with an excitation light having a luminescence peak in the wavelength range of 250 to 460 nm.SELECTED DRAWING: Figure 7

Description

  Embodiments described herein relate generally to a phosphor mixture and a light emitting device using the same.

  In recent years, research on light emitting devices using LEDs has been advanced, and high color rendering properties and good light emission efficiency have been demanded particularly in white LED light emitting devices.

JP 2012-197412

  In order to meet such a demand, an embodiment according to the present invention is intended to provide a white LED light-emitting device having high color rendering properties or excellent light emission efficiency with suppressed color breakup.

The phosphor mixture according to the embodiment is:
When excited with excitation light having an emission peak in the wavelength range of 250 to 460 nm, the emission peak is shown in the wavelength range of 510 to 570 nm, and the following general formula (a):
^{_{((Sr pa M a 1-}} pa) 1-xa Ce xa) 2ya Al za Si 10-za O ua N wa (a)
(In the formula (a),
M ^a is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pa ≦ 1,
0 <xa ≦ 1,
0.8 ≦ ya ≦ 1.1,
2 ≦ za ≦ 3.5,
0 <ua ≦ 1,
1.8 ≦ za−ua and 13 ≦ ua + wa ≦ 15
Is)
A yellow light-emitting phosphor having a composition represented by:
and,
When excited with the excitation light, it shows an emission peak in the wavelength range of 430 to 500 nm, and the following general formula (b):
^{_{((Sr pb M b 1-}} pb) 1-xb Ce xb) 3-yb Si 13-zb Al 3 + zb O 2 + ub N 21-wb (b)
(In the formula (b),
M ^b is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pb ≦ 1,
0 <xb ≦ 1,
−0.1 ≦ yb ≦ 0.6,
−3.0 ≦ zb ≦ 0.4,
−1.5 <ub ≦ −0.3, and −3.0 <ub−wb ≦ 1.0
Is)
It contains the blue light emission fluorescent substance which has a composition represented by these.

The light emitting device according to the embodiment
It comprises a light emitting element that emits excitation light having an emission peak within a wavelength range of 250 to 460 nm, and the phosphor mixture.

Moreover, the manufacturing method of the phosphor in the phosphor mixture according to the embodiment is a manufacturing method of the phosphor mixture,
Sr-containing raw materials selected from Sr nitrides, silicides, carbides, carbonates, hydroxides, and oxides, and M nitrides, silicides, carbides, carbonates, hydroxides, and oxides M-containing raw material selected, Al-containing raw material selected from Al nitride, oxide and carbide, Si-containing raw material selected from Si nitride, oxide and carbide, Ce chloride, oxidation A mixing step of mixing a Ce-containing raw material selected from an oxide, a nitride and a carbonate to obtain a mixture;
And baking the mixture at a temperature of 1500 to 2000 ° C. under a pressure equal to or higher than atmospheric pressure.

It shows the crystal structure of _{Sr 2 Si 7 Al 3 ON 13} . It shows the crystal structure of _{Sr 3 Si 13 Al 3 O 2} N 21. Schematic showing the structure of the light-emitting device concerning one Embodiment. Schematic showing the structure of the light-emitting device concerning other embodiment. 3 is an XRD profile of a blue light emitting phosphor according to Example 1. FIG. 3 is an XRD profile of a yellow light emitting phosphor according to Example 1. FIG. Emission spectrum emitted from the light emitting device. Emission spectrum emitted from the light emitting device. Emission spectrum emitted from the light emitting device.

  The embodiment will be specifically described below.

[Composition of yellow light emitting phosphor and blue light emitting phosphor]
The phosphor mixture according to one embodiment includes a yellow light-emitting phosphor and a blue light-emitting phosphor. The yellow light-emitting phosphor contained in this phosphor, when excited with excitation light having a light emission peak in the wavelength range of 250 to 460 nm, from light having a light emission peak in the wavelength range of 510 to 570 nm, that is, yellowish green It emits light in an orange area. The yellow light-emitting phosphor includes a base material having a crystal structure substantially the same as the crystal structure of Sr ₂ Si ₇ Al ₃ ON ₁₃ , and the base material is activated with Ce. In the present embodiment, the composition of the yellow light-emitting phosphor is represented by the following general formula (a).
^{_{((Sr pa M a 1-}} pa) 1-xa Ce xa) 2ya Al za Si 10-za O ua N wa (a)
here,
M ^a is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pa ≦ 1,
0 <xa ≦ 1,
0.8 ≦ ya ≦ 1.1,
2 ≦ za ≦ 3.5,
0 <ua ≦ 1,
1.8 ≦ za-ua,
13 ≦ ua + wa ≦ 15
It is.

^{_{((Sr pb M b 1-}} pb) 1-xb Ce xb) 3-yb Si 13-zb Al 3 + zb O 2 + ub N 21-wb (b)
Here, M ^b is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pb ≦ 1,
0 <xb ≦ 1,
−0.1 ≦ yb ≦ 0.6,
−3.0 ≦ zb ≦ 0.4,
−1.5 <ub ≦ −0.3,
−3.0 <ub−wb ≦ 1.0
It is.

As shown in the general formula (b), the luminescent center element Ce substitutes a part of the metal element constituting the phosphor crystal. ^Mb is at least one of an alkali metal or an alkaline earth metal, and is preferably at least one selected from Ba, Ca, and Mg. If pb is 0.85 or more, more desirably 0.9 or more, the generation of a heterogeneous phase is not promoted. In some cases, it is desirable that pb is 1 in order to optimize the light emission characteristics of the phosphor. Even in such a case, a metal other than Sr or Ce may be included as an inevitable impurity. is there. In such a case, the effect of the present invention is generally sufficiently exhibited.

When 0.1 mol% or more of the total of Sr, M ^b , and Ce is Ce, sufficient luminous efficiency can be obtained. Sr and M may not be contained (xb = 1), but when xb is less than 0.5, a decrease in light emission efficiency (concentration quenching) can be suppressed as much as possible. Therefore, xb is preferably 0.001 or more and 0.5 or less. When the luminescent center element Ce is contained, the phosphor according to this embodiment exhibits light emission in a blue region, that is, light emission having a peak in a wavelength range of 430 to 500 nm when excited with the excitation light. In addition, even if a part of Ce is substituted with other metal elements that are inevitable impurities, desired characteristics are not impaired. Examples of such inevitable impurities include Tb, Eu, and Mn. Specifically, the ratio of inevitable impurities to the total of Ce and inevitable impurities is preferably 15 mol% or less, and more preferably 10 mol% or less.

  When yb is 0.6 or more, crystal defects may increase. On the other hand, if yb is less than −0.1, excessive alkaline earth metal precipitates as a heterogeneous phase, which may lead to deterioration in light emission characteristics. yb is preferably −0.05 ≦ yb ≦ 0.4.

  When zb is less than −3.0 or greater than 0.4, excess Si or excess Al may precipitate as a heterogeneous phase. In general, −3.0 ≦ zb ≦ 0.4, and preferably −1.5 ≦ zb ≦ 0.2.

  When ub is −1.5 or less, crystal defects may increase. u is preferably −1.2 ≦ ub ≦ 0.

  When (ub-wb) is less than −3.0 or exceeds 1.0, the crystal structure specified in the present embodiment may not be maintained. In some cases, a heterogeneous phase is generated, and the effect of this embodiment is not exhibited. ub is preferably −2.0 ≦ ub−wb ≦ 0.5.

  The yellow light emitting phosphor and the blue light emitting phosphor according to the present embodiment contain Al and Si. Here, Al and Si may be substituted with similar elements as long as the effects of the present invention are not impaired. Specifically, a part of Si may be substituted with Ge, Sn, Ti, Zr, and Hf, and a part of Al is replaced with Ga, In, Sc, Y, La, Gd, Lu, and the like. May be substituted. These elements are preferably 10 mol% or less of the total of Si, Al, and similar elements.

  Since the yellow light-emitting phosphor and the blue light-emitting phosphor according to the present embodiment have all the preferable conditions described above, they can emit yellow light and blue light with high efficiency, respectively, when excited with the excitation light. .

[Structures of yellow-emitting phosphor and blue-emitting phosphor]
The yellow light-emitting phosphor in the present embodiment is based on Sr ₂ Si ₇ Al ₃ ON ₁₃ crystal, and its constituent elements Sr, Si, Al, O, or N are replaced with other elements, or other elements such as Ce It can also be said that the metal element is a solid solution. In the present embodiment, such a crystal is called a Sr ₂ Si ₇ Al ₃ ON _{13 group} crystal. Although such a replacement may slightly change the crystal structure, the atomic position is rarely changed so much that the chemical bond between the skeletal atoms is broken. The atomic position is given by the crystal structure, the site occupied by the atom and its coordinates.

The Sr ₂ Si ₇ Al ₃ ON ₁₃ crystal belongs to a monoclinic system, particularly an orthorhombic system, and the lattice constants are a = 11.8Å, b = 21.6Å, and c = 5.01Å. Moreover, it belongs to space group Pna21. The chemical bond length (Sr—N and Sr—O) in Sr ₂ Si ₇ Al ₃ ON ₁₃ can be calculated from the atomic coordinates shown in Table 1 below.

Whether the structure of the yellow light emitting phosphor and the Sr ₂ Si ₇ Al ₃ ON ₁₃ crystal in this embodiment is the same can be determined by XRD or neutron diffraction. In the present embodiment, the yellow light-emitting phosphor has a peak at a specific diffraction angle (2θ) in an X-ray diffraction pattern by the Bragg-Brendano method using Cu—Kα rays. In the X-ray diffraction using CuKα characteristic X-ray (wavelength 1.54056Å), the yellow light-emitting phosphor in the present embodiment is 15.05-15.15, 23.03-23.13, 24.90-25. 00, 25.70 to 25.80, 25.98 to 26.08, 29.29 to 29.39, 30.94 to 31.04, 31.61 to 1.71, 31.88 to 31.98, 33.05 to 33.15, 33.62 to 33.72, 34.40 to 34.50, 35.25 to 35.35, 36.09 to 36.19, 36.52 to 36.62, 37. Of the diffraction angles (2θ) of 16 to 37.26 and 56.42 to 56.52, 17 positions, preferably, at least 10 positions simultaneously exhibit diffraction peaks.

In this embodiment, the blue light-emitting phosphor is based on Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ crystal, and its constituent elements, Si and Al, or O and N are replaced with each other, Ce, etc. It can also be said that other metal elements are in solid solution. In the present embodiment, such a crystal is called a Sr ₃ Si ₁₃ Al ₃ O ₂ N _{21 group} crystal. Although such a replacement may slightly change the crystal structure, the atomic position is rarely changed so much that the chemical bond between the skeletal atoms is broken. The atomic position is given by the crystal structure, the site occupied by the atom and its coordinates.

The effects of the present embodiment can be achieved as long as the basic crystal structure of the blue light emitting phosphor according to the present embodiment does not change. In the phosphor according to this embodiment, the lattice constant and the length of the chemical bond of Sr—N and Sr—O (distance between adjacent atoms) are different from those of Sr ₃ Si ₁₃ Al ₃ O ₂ N _21. is there. Difference of the corresponding length of the chemical _{bond, Sr 3 Si 13 Al 3 O} 2 lattice constants of structure crystal has a _{N 21,} and _Sr 3 _Si 13 _Al 3 _O 2 length of chemical bonds in the _{N 21} (Sr If it is within ± 15% of -N and Sr-O), it is defined that the crystal structure is not changed. The lattice constant can be determined by X-ray diffraction or neutron diffraction, and the length of chemical bonds (interatomic distance) of Sr—N and Sr—O can be calculated from atomic coordinates.

The Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ crystal belongs to the monoclinic system, particularly the orthorhombic system. The lattice constants are a = 14.8１４, b = 7.5Å, and c = 9.0Å.

  It is essential that the blue light emitting phosphor in this embodiment has such a crystal structure. If the length of the chemical bond is changed beyond this range, the chemical bond may be broken to form another crystal structure, and the effects according to the present embodiment may not be obtained.

The blue-emitting phosphor in the present embodiment is based on an inorganic compound having substantially the same crystal structure as Sr ₃ Si ₁₃ Al ₃ O ₂ N _21, and a part of the constituent element Sr is replaced with the luminescent center ion Ce. The composition of each element is defined within a predetermined range. At this time, a desirable characteristic of high quantum efficiency is exhibited.

Whether the structures of the blue light emitting phosphor and the Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ crystal in the present embodiment are the same can be determined by XRD or neutron diffraction. The phosphor according to the present embodiment has a peak at a specific diffraction angle (2θ) in an X-ray diffraction pattern by the Bragg-Brendano method using Cu—Kα rays. The blue light-emitting phosphor according to the present embodiment is 15.3 to 15.5 °, 25.7 to 25.9 °, and 29.6 to X-ray diffraction using CuKα characteristic X-ray (wavelength 1.54056Å). Diffraction angles (2θ) of 29.8 °, 30.84 to 31.04 °, 30.95 to 31.15 °, 31.90 to 32.10 °, and 37.35 to 37.55 °, 7 locations Among them, it is preferable to show diffraction peaks at least at five locations simultaneously.

[Physical properties of yellow-emitting phosphor and blue-emitting phosphor]
The yellow light emitting phosphor according to this embodiment preferably has a particle size of 5 μm to 40 μm, more preferably 10 μm to 38 μm. Further, the blue light emitting phosphor generally has a larger particle size than the yellow light emitting phosphor. However, it is possible to obtain a particle size equivalent to that of the yellow light-emitting phosphor by crushing the blue light-emitting phosphor or adjusting the firing conditions such as temperature and time. The yellow light-emitting phosphor or the blue light-emitting phosphor according to this embodiment can suppress clogging of the dispenser for supplying the composition containing the phosphor when the light-emitting device is manufactured because the particle size is small. In addition, since the crystal particles hardly settle in the composition, there is an advantage that the production yield is improved. Furthermore, in the formed light emitting device, since the particles are small, there is an advantage that the phosphor is easily distributed uniformly in the light emitting layer, and the color unevenness of light emission is small.

  The blue light-emitting phosphor according to the embodiment has a wide half-value emission spectrum compared to the BAM phosphor that is widely commercialized as a blue light-emitting phosphor, and white light emission having high color rendering properties by using the phosphor according to the embodiment. An apparatus can be obtained.

  The blue light-emitting phosphor in the embodiment has little absorption around a wavelength of 450 nm. For this reason, the blue light emitted from the blue light emitting phosphor or the blue light emitted from the excitation light source is emitted to the outside, and thus becomes a part of the light emitted from the light emitting device. By effectively using such light, a light emitting device having excellent color rendering properties can be obtained, and color breakup described later is less likely to occur.

  The yellow light emitting phosphor and the blue light emitting phosphor according to the embodiment have a blue light refractive index in the range of 1.8 to 2.3. Usually, when the phosphor layer is formed, the refractive index of the silicone resin constituting the matrix is about 1.4 to 1.6, which is lower than the refractive index of the yellow light emitting phosphor and the blue light emitting phosphor. For this reason, it is considered that the difference between the refractive index of the resin constituting the matrix of the phosphor layer and the refractive index of the phosphor increases scattering and has an effect of suppressing color breakup.

[Phosphor mixture containing yellow-emitting phosphor and blue-emitting phosphor]
The mixing ratio of the mixture comprising the yellow light-emitting phosphor and the blue light-emitting phosphor according to the present embodiment is not particularly limited, but is preferably in a mass ratio of 98: 2 to 2:98, more preferably 10: 90-90: 10.
Further, the phosphor mixture may include a phosphor other than the yellow light-emitting phosphor and the blue light-emitting phosphor. For example, a green light emitting phosphor and a red light emitting phosphor can be used.

[Method for producing phosphor mixture]
The phosphor mixture according to the present embodiment can be manufactured by any method. For example, a yellow light-emitting phosphor and a blue light-emitting phosphor can be separately manufactured as described later, and then mixed at an arbitrary ratio. Further, the yellow light emitting phosphor and the blue light emitting phosphor can be simultaneously manufactured by a single process. Usually, when manufacturing a yellow light emission fluorescent substance or a blue light emission fluorescent substance, a raw material is mix | blended with the design composition. That is, in the case of a yellow light emitting phosphor, raw materials are blended in accordance with Sr ₂ Si ₇ Al ₃ ON ₁₃ or a composition close thereto, and in the case of a blue light emitting phosphor, Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ genus or The raw materials are blended so that the composition approximates that. On the other hand, when manufacturing with a single process, if the Si content of the raw material is increased within the range of firing conditions in which the yellow phosphor and the blue phosphor are simultaneously produced, the production ratio of the blue phosphor Tend to be higher. Furthermore, either a yellow light emitting phosphor or a blue light emitting phosphor, or both can be further mixed with the phosphor mixture produced by a single process.

  The phosphor mixture according to the present embodiment or the yellow or blue light-emitting phosphor used therefor can be produced by any method. For example, it is produced by mixing and firing raw material powders containing each element. Can do.

  The Sr-containing raw material can be selected from Sr nitrides, silicides, carbides, carbonates, hydroxides, and oxides. The M-containing raw material can be selected from M nitrides, silicides, carbides, carbonates, hydroxides, and oxides. The Al-containing raw material can be selected from Al nitrides, oxides and carbides, and the Si-containing raw material can be selected from Si nitrides, oxides and carbides. The Ce-containing raw material can be selected from Ce chlorides, oxides, nitrides and carbonates.

  The firing of the raw material mixture is desirably performed at a pressure higher than atmospheric pressure. Firing at a pressure higher than atmospheric pressure is advantageous in that silicon nitride is difficult to decompose. In order to suppress decomposition of silicon nitride at a high temperature, the pressure (absolute pressure) is more preferably 5 atm or more, and the firing temperature is preferably in the range of 1400 to 2000 ° C. Under such conditions, the desired sintered body can be obtained without causing problems such as sublimation of the material or product. As will be described later, when there are a plurality of firing steps, it is preferable to perform part or all of the firing step under pressure, and it is more preferable to perform all of the firing step under pressure.

  In addition, it is preferable that the manufacturing method of the phosphor according to the present embodiment includes two or more firing steps in which the firing temperature is changed, and the temperature of the subsequent firing step is higher than the firing temperature of the first firing step. It is preferable.

  For this reason, the intermediate product obtained by the primary baking process which bakes a raw material mixture at the baking temperature of 1400-1700 degreeC, Preferably 1500-1700 degreeC, and a primary baking process is 1800-2000 degreeC, Preferably it is 1800. It is preferable to combine with a secondary firing step of firing at a firing temperature of ˜1900 ° C. In addition, when the yellow light emitting phosphor and the blue light emitting phosphor are simultaneously manufactured by a single process, the firing temperature range is preferably 1700-1900 ° C. However, the lower the firing temperature, the higher the generation ratio of the blue phosphor. Tend.

The firing atmosphere preferably has a low oxygen content in any firing step. This is to avoid oxidation of raw materials such as Sr ₃ N ₂ and AlN. Specifically, it is desirable to perform firing in a nitrogen atmosphere, a high-pressure nitrogen atmosphere, or a deoxygenated atmosphere. The atmosphere may contain hydrogen molecules up to about 50 vol%.

  Moreover, although baking time is not specifically limited, For example, it is 4 to 80 hours, Preferably it is 6 to 60 hours. When the yellow light-emitting phosphor and the blue light-emitting phosphor are simultaneously manufactured by a single process, the generation ratio of the yellow phosphor tends to increase as the firing time is increased.

[Light emitting device]
The light emitting device according to the embodiment includes a light emitting element that is an excitation light source, and the yellow light emitting phosphor (Y) and the blue light emitting phosphor (B) that are excited by light emitted from the light emitting element and emit fluorescence. A combination with a phosphor mixture is provided. At this time, the light emitting device emits light obtained by combining light emitted from the light emitting element and light emitted from the yellow light emitting phosphor and the blue light emitting phosphor.

  A light-emitting element used in a light-emitting device, for example, an LED element, requires that light emitted therefrom can excite the phosphor used.

  From such a viewpoint, in a fluorescent device using a phosphor mixture containing a yellow fluorescent substance and a blue light emitting fluorescent substance as a fluorescent substance, the light emitting element is 250 to 460 nm, and preferably 250 to 460 when high color rendering properties are required. When 400 nm and high efficiency are calculated | required, Preferably, what emits the light of the wavelength which has a light emission peak in the 430-460 nm area | region is selected.

  In addition, the light-emitting device by embodiment can also combine the fluorescent substance which radiates | emits the light of another wavelength range other than the said fluorescent substance mixture. As such a phosphor, a phosphor exhibiting light emission having a peak within a wavelength range of 490 to 580 nm (green light emitting phosphor (G)), a phosphor exhibiting light emission having a peak within a wavelength range of 600 to 660 nm. (Red light emitting phosphor (R)) and the like. These phosphors may be excited by light emitted from the light emitting element, or may be excited by light emitted from the yellow light emitting phosphor and the blue light emitting phosphor. These phosphors are used in an appropriate combination according to the color, color temperature, color rendering, etc. of light emitted from the target light emitting device.

  The light emitting device according to the embodiment may be in the form of any conventionally known light emitting device. FIG. 3 shows a cross section of a light emitting device according to an embodiment of the present invention.

  The light emitting device according to the embodiment of the present invention can be in the form of any conventionally known light emitting device. FIG. 3 shows a cross section of a light emitting device according to an embodiment of the present invention.

  In the light emitting device shown in FIG. 3, the base material 300 includes a lead 301 and a lead 302 formed by forming a lead frame, and a resin portion 303 formed integrally therewith. The resin portion 303 has a concave portion 305 whose upper opening is wider than the bottom surface portion, and a reflective surface 304 is provided on a side surface of the concave portion.

  A light emitting element 306 is mounted with Ag paste or the like at the center of the substantially circular bottom surface of the recess 305. As the light emitting element 306, for example, a light emitting diode, a laser diode, or the like can be used. This light emitting element is selected from those emitting light of an appropriate wavelength according to the combination of phosphors used. For example, a GaN-based semiconductor light emitting element or the like can be used. An electrode (not shown) of the light emitting element 306 is connected to the lead 301 and the lead 302 by bonding wires 307 and 308 made of Au or the like, respectively. The arrangement of the leads 301 and 302 can be changed as appropriate.

  The fluorescent layer 309 can be formed by dispersing or precipitating the necessary phosphor 310 in a resin layer 311 made of, for example, a silicone resin at a rate of 5 to 70% by weight. Here, the phosphor can be used by combining the yellow light-emitting phosphor (Y) and the blue light-emitting phosphor (B) according to the embodiment with another phosphor such as a green light-emitting phosphor (G). . In the phosphor according to the embodiment, oxynitride having high covalent bond is used as a base material. For this reason, the phosphor according to the embodiment of the present invention is generally hydrophobic and has very good compatibility with the resin. Therefore, scattering at the interface between the resin and the phosphor is remarkably suppressed, and the light extraction efficiency is improved.

  As the light emitting element 306, a flip chip type having an n-type electrode and a p-type electrode on the same surface can be used. In this case, problems caused by the wire such as wire breakage and peeling and light absorption by the wire are solved, and a highly reliable and high-luminance semiconductor light-emitting device can be obtained. In addition, an n-type substrate can be used for the light emitting element 306 to have the following configuration. Specifically, an n-type electrode is formed on the back surface of the n-type substrate, a p-type electrode is formed on the upper surface of the semiconductor layer on the substrate, and the n-type electrode or the p-type electrode is mounted on a lead. The p-type electrode or the n-type electrode can be connected to the other lead by a wire. The size of the light emitting element 306 and the size and shape of the recess 305 can be changed as appropriate.

A light emitting device using a BaMgAl: Eu ²⁺ phosphor commonly used as a blue light emitting phosphor has a low emission intensity per 500 nm. However, when a light-emitting device that emits white light is produced by combining a mixture of a yellow-emitting phosphor and a blue-emitting phosphor according to the present embodiment and a red-emitting phosphor and a light-emitting element having a wavelength of 365 nm, the light-emitting device has a wavelength of about 500 nm. The amount of light emitted from is high, and the color rendering is high.

  When manufacturing a light emitting device that emits white light, a blue LED is generally combined with a yellow light emitting phosphor. In this case, so-called color breakage, in which the light emission intensity directly above the light emitting element is high and the light emission intensity in the peripheral part is low, may be a problem. Therefore, when the phosphor mixture according to the present invention is used instead of the conventional yellow light-emitting phosphor, the blue light-emitting phosphor in the phosphor mixture has a refractive index higher than that of the resin and emits blue light emitted from the light-emitting element. In addition, since it hardly absorbs light emitted from the yellow light-emitting phosphor, it functions as a scatterer in the resin, and is considered to suppress color breakage of the white light-emitting device.

  Hereinafter, the present invention will be described in more detail with reference to various examples, but the present invention is not limited to only these examples.

Example 1
SrSi ₂ , CeCl ₃ , Si ₃ N ₄ , Al ₂ O ₃ , and AlN were prepared and weighed as Sr-containing materials, Ce-containing materials, Si-containing materials, and Al-containing materials. The blending mass was 4.120 g, 0.333 g, 3.400 g, 0.510 g, and 0.820 g to obtain a raw material mixture. The design composition of the phosphor at this time was (Sr _0.955 Ce _0.045 ) ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ . This raw material mixture was filled in a BN crucible and fired. In Example 1, first, in an atmosphere where the mixing ratio (molar ratio) of H ₂ : N ₂ was 1: 1, heating was performed at 1500 ° C. under 1 atmosphere for 12 hours, and the obtained fired product was crushed. After repeating this three times, heating was performed at 7.5 atm. 1850 ° C. for 10 hours under a nitrogen atmosphere, and the obtained fired product was crushed to obtain blue-emitting phosphor B1 contained in the phosphor mixture of Example 1. Obtained. All the obtained phosphors emitted blue light when irradiated with excitation light of 365 nm.

Moreover, Sr ₃ N ₂ , CeCl ₃ , Si ₃ N ₄ , and AlN were prepared as Sr-containing materials, Ce-containing materials, Si-containing materials, and Al-containing materials, and weighed in a vacuum glove box. The blending masses of Sr ₃ N ₂ , CeCl ₃ , Si ₃ N ₄ , and AlN were 2.902 g, 0.148 g, 5.262 g, and 1.537 g, respectively. Phosphor design composition at this time _{was (Sr 9.98 Ce 0.02) 2 Si} 7.5 Al 2.5 N 14. The blended raw material powder was dry mixed.

  The obtained mixture was placed in a boron nitride crucible and baked at 1850 ° C. for 8 hours in a nitrogen atmosphere of 7.5 atm. Thus, a yellow light-emitting phosphor Y1 contained in the phosphor mixture of Example 1 was obtained.

  Sr, Si, Al, and Ce can be measured by, for example, inductively coupled plasma emission spectroscopy (sometimes referred to as ICP emission spectroscopy). Specifically, a sample of the oxynitride phosphor is weighed into a platinum crucible, decomposed by alkali melting, an internal standard element Y is added to prepare a measurement solution, and measurement is performed by ICP emission spectroscopic analysis. For Sr, Si, and Ce, for example, an SPS-3520UV4000 type ICP emission spectroscopic analyzer (trade name, manufactured by SII Nanotechnology Co., Ltd.) can be used as the measuring device.

O and N can be measured, for example, by an inert gas melting method. Specifically, a sample of an oxynitride phosphor is heated and melted in a graphite crucible, O contained in the sample is converted to CO by an inert gas transfer method, and further oxidized to CO ₂ , and then an infrared absorption method is used. The oxygen content is measured, and after removing CO ₂ , the N content is measured by a heat conduction method. As the measuring apparatus, for example, a TC-600 type oxygen / nitrogen / hydrogen analyzer (trade name, manufactured by LECO Corporation (USA)) can be used.

  The results of composition analysis of phosphors Y1 and B1 are as shown in Table 2. The composition described in the table is standardized so that Si + Al = 10 for Y1 and Si + Al = 16 for B1.

  In addition, the XRD profiles of Y1 and B1 of the phosphor manufactured by the same method are as shown in FIGS. 5 and 6, respectively. These phosphors have a peak at a specific diffraction angle (2θ) in an X-ray diffraction pattern by the Bragg-Brendano method using CuKα characteristic X-rays (wavelength 1.54056Å).

The white light emitting material of Example 1 that emits white light that combines the above-described yellow light-emitting phosphor Y1, the phosphor mixture BY1 mixed with the blue light-emitting phosphor B1, the red phosphor (SCASN), and a light-emitting element having a wavelength of 365 nm. A light emitting device was manufactured. Further, as a comparative example, a comparative light emitting device was manufactured using a BaMgAl: Eu ²⁺ phosphor commonly used as a blue light emitting phosphor. The simulation results of the emission spectra of these light emitting devices are as shown in FIG. It was confirmed that the light emitting device using the phosphor mixture of Example 1 had a large amount of light emission in the vicinity of 500 nm and high color rendering properties.

  A light emitting device similar to that described above was manufactured using phosphor mixtures BY2, BY3, and BY4 that were manufactured in the same manner as described above except for the mixing ratio of the raw materials and that had the compositions described in Table 3 below. Moreover, the comparative example used the same thing as the above. The simulation results of the emission spectra of these light emitting devices are as shown in FIG.

Example 2
In the case of manufacturing a light emitting device that emits white light in which the phosphor mixture BY1 and a light emitting element having a wavelength of 450 nm are combined, the blue light emitting phosphor in the phosphor mixture has a refractive index higher than that of the resin, and the blue light of the light emitting element. And the yellow light-emitting phosphor hardly absorbs light, so that it functions as a scatterer in the resin, and the white light-emitting element has few color breaks.

Example 3
The phosphor mixture BY5, BY6, and BY7 having the composition described in Table 4 below, a red phosphor (SCASN), and a wavelength of 450 nm are manufactured in the same manner as described above except for the mixing ratio of the raw materials. A light-emitting device of Example 3 that emits white light in combination with the light-emitting element was manufactured. The simulation results of the emission spectra of these light emitting devices are as shown in FIG.

Example 4
A raw material mixture is obtained by weighing and mixing the raw materials so as to obtain a desired mixing ratio. This raw material mixture is filled in a BN crucible and fired. After firing, the obtained fired product is crushed to obtain a phosphor mixture BY8 containing a yellow light-emitting phosphor and a blue light-emitting phosphor. The obtained phosphor mixture emits light in a blue to yellow region when irradiated with excitation light of 365 nm.

  The phosphor mixture BY8, the red phosphor (SCANAN), and a light emitting device having a wavelength of 365 nm are combined to produce a light emitting device that emits white light. The light emitting device using the phosphor mixture of Example 3 has high emission intensity near 500 nm and high color rendering.

Example 5
In the case of manufacturing a light emitting device that emits white light in which a phosphor mixture BY8 and a light emitting element with a wavelength of 450 nm are combined, the blue light emitting phosphor in the phosphor mixture has a higher refractive index than the resin, and the blue light of the light emitting element, And since it hardly absorbs the light emission of the yellow light emitting phosphor, it functions as a scatterer in the resin, and the white light emitting element has few color breaks.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

101 Sr atom 102 Si atom or Al atom 103 O atom or N atom 201 Sr atom 202 Si atom or Al atom 203 O atom or N atom 204 Site 300 having an occupation ratio of Si atom or Al atom 0.5 Substrate 301, 302 Lead 303, package cup 304, reflective surface 305, concave portion;
306 Light emitting chips 307 and 308 Bonding wire 309 Fluorescent light emitting layer 310 Phosphor 311 Resin layer 400 Light emitting element 401 Ultraviolet light emitting diode 402 Substrate 403 Gold wire 404 and 406 Transparent resin layer 405 Transparent resin layer 407 containing red light emitting phosphor Yellow light emitting fluorescence Body and transparent resin layer containing blue-emitting phosphor

Claims (12)

When excited with excitation light having an emission peak in the wavelength range of 250 to 460 nm, the emission peak is shown in the wavelength range of 510 to 570 nm, and the following general formula (a):
^{_{((Sr pa M a 1-}} pa) 1-xa Ce xa) 2ya Al za Si 10-za O ua N wa (a)
(In the formula (a),
M ^a is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pa ≦ 1,
0 <xa ≦ 1,
0.8 ≦ ya ≦ 1.1,
2 ≦ za ≦ 3.5,
0 <ua ≦ 1,
1.8 ≦ za−ua and 13 ≦ ua + wa ≦ 15
Is)
A yellow light-emitting phosphor having a composition represented by:
and,
When excited with the excitation light, it shows an emission peak in the wavelength range of 430 to 500 nm, and the following general formula (b):
^{_{((Sr pb M b 1-}} pb) 1-xb Ce xb) 3-yb Si 13-zb Al 3 + zb O 2 + ub N 21-wb (b)
(In the formula (b),
M ^b is at least one of an alkali metal or an alkaline earth metal,
0 ≦ pb ≦ 1,
0 <xb ≦ 1,
−0.1 ≦ yb ≦ 0.6,
−3.0 ≦ zb ≦ 0.4,
−1.5 <ub ≦ −0.3, and −3.0 <ub−wb ≦ 1.0
Is)
A phosphor mixture comprising a blue-emitting phosphor having a composition represented by: The phosphor mixture according to claim 1, wherein said M ^a and M ^b are each independently an element selected from the group consisting of Ba, Ca, and Mg. The difference of the lattice constant in the crystal of the yellow light-emitting phosphor with respect to the lattice constant of the structure of the crystal of Sr ₂ Si ₇ Al ₃ ON ₁₃ is within ± 15%,
The fluorescence according to claim 1 or 2, wherein a difference of a lattice constant in the crystal of the blue light emitting phosphor with respect to a lattice constant of a structure of the crystal of Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ is within ± 15%. body. The difference in the chemical bond lengths of MN and MO in the crystal of the yellow light emitting phosphor with respect to the chemical bond lengths of Sr—N and Sr—O in Sr ₂ Si ₇ Al ₃ ON ₁₃ is ± Within 15%
The difference in the chemical bond lengths of MN and MO in the crystal of the blue light emitting phosphor with respect to the chemical bond lengths of Sr—N and Sr—O in Sr ₃ Si ₁₃ Al ₃ O ₂ N ₂₁ is The phosphor according to any one of claims 1 to 3, which is within ± 15%. In X-ray diffraction by the Bragg-Brendano method using Cu-Kα rays,
The yellow light emitting phosphor is 15.05 to 15.15, 23.03 to 23.13, 24.90 to 25.00, 25.70 to 25.80, 25.98 to 26.08, 29.29. ~ 29.39, 30.94 ~ 31.04, 31.61 ~ 31.71, 31.88 ~ 31.98, 33.05 ~ 33.15, 33.62 ~ 33.72, 34.40 ~ 34 At diffraction angles (2θ) of .50, 35.25 to 35.35, 36.09 to 36.19, 36.52 to 36.62, 37.16 to 37.26, and 56.42 to 56.52 Have at least 10 peaks,
The blue light-emitting phosphor is 15.3 to 15.5 °, 25.7 to 25.9 °, 29.6 to 29.8 °, 30.84 to 31.04 °, 30.95 to 31.15. The fluorescence according to any one of claims 1 to 4, which has at least 5 peaks at diffraction angles (2θ) of °, 31.90 to 32.10 °, and 37.35 to 37.55 °. body. The yellow light-emitting phosphor is a Sr ₂ Si ₇ Al ₃ ON _{13 group} crystal, and the blue light-emitting phosphor is a Sr ₃ Si ₁₃ Al ₃ O ₂ N _{21 group} crystal. The phosphor according to Item.   A light-emitting device comprising: a light-emitting element that emits excitation light having an emission peak in a wavelength range of 250 to 460 nm; and the phosphor mixture according to claim 1.   The light emitting device according to claim 7, wherein the excitation light is light having an emission peak in a wavelength range of 430 to 460 nm. A light emitting device that emits light having an emission peak in a wavelength range of 250 to 460 nm;
The phosphor mixture according to any one of claims 1 to 6,
A phosphor exhibiting light emission having a peak in a wavelength range of 600 to 660 nm when excited by light from the light emitting element;
A light-emitting device comprising:   The light emitting device according to claim 9, wherein the light emitting element emits light having a light emission peak in a wavelength range of 430 to 460 nm. It is a manufacturing method of the fluorescent substance mixture of any one of Claims 1-6,
Sr-containing raw materials selected from Sr nitrides, silicides, carbides, carbonates, hydroxides, and oxides, and M nitrides, silicides, carbides, carbonates, hydroxides, and oxides M-containing raw material selected, Al-containing raw material selected from Al nitride, oxide and carbide, Si-containing raw material selected from Si nitride, oxide and carbide, Ce chloride, oxidation A mixing step of mixing a Ce-containing raw material selected from an oxide, a nitride and a carbonate to obtain a mixture;
And baking the mixture at a temperature of 1400 to 2000 ° C. under a pressure equal to or higher than atmospheric pressure.   The method according to claim 10, wherein part or all of the firing is performed under a pressurized condition of 5 atm or more.

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