JP2015054950A - Fluorescent substance, and fluorescent substance-containing composition and light-emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent substance of a new composition which is easy to produce and emits yellow to blue light suitable for lighting applications.SOLUTION: The fluorescent substance has a chemical composition represented by the following formula (1) and contains a crystal phase which, when 3 diffraction peaks in order of decreasing intensity are selected in a powder X-ray diffraction pattern using CuKα rays, Bragg angles (2θ) of the 3 diffraction peaks are in ranges of 24.5° to 25.5°, 28.7° to 29.7°, 32.5° to 33.5°. The formula (1) is MPO:R (M represents a constituent element containing one or more kinds of alkaline earth elements; R represents an additional element including one or more kinds of light-emitting center elements; and 6.3≤m≤7.7, 3.6≤a≤4.4, and 15.3≤o≤18.7 are satisfied).

Description

  The present invention relates to a phosphor that emits yellow to blue fluorescence, a phosphor-containing composition using the phosphor, and a light-emitting device.

  The phosphor is used for a fluorescent display tube (VFD), a field emission display (FED), a plasma display panel (PDP), a cold cathode tube (CRT), an LED light emitting device, and the like. In any of these applications, in order to cause the phosphor to emit light, it is necessary to supply energy for exciting the phosphor to the phosphor. The phosphor is excited by an excitation source having high energy such as vacuum ultraviolet rays, ultraviolet rays, electron beams, blue light, and emits visible light.

  In recent years, there has been a demand for a light emitting device that emits white light with high color rendering and color reproducibility. To achieve this, conventional silicate phosphors, phosphate phosphors, aluminate phosphors, New phosphors are being searched for for phosphors such as sulfide phosphors. For example, Patent Document 1 discloses a phosphate phosphor that emits yellow light. Non-Patent Documents 1 to 3 disclose calcium phosphate phosphors having various emission wavelengths.

  On the other hand, as shown in Non-Patent Document 4, yttrium / aluminum / garnet (YAG) phosphors are widely known as phosphors that emit yellow to orange light.

JP2012-144665A

Deng Deng et al, Journal of Materials Chemistry C 2013, 1, page 3194-3199. Journal of the American Ceramic Society, Volume 96, Issue 4, pages 1043-1046, 2013 Journal of Materials Chemistry C, 2013, 1, 5577-5582 Phosphor Handbook, Second Edition, 2006, 533-539

  The phosphor described in Patent Document 1 is a yellow phosphor, but has a mixed spectrum of a green light emitting component (˜530 nm) and an orange light emitting component (˜600 nm), as an alternative to a YAG phosphor having only a yellow light emitting component. Not suitable for lighting applications.

The phosphor described in Non-Patent Document 1 is a red phosphor, and its emission peak wavelength is a little long wave (up to 665 nm peak), which is disadvantageous in terms of visibility and cannot secure brightness in illumination applications. In addition, the phosphor described in Non-Patent Document 2 is a blue phosphor, which has a peak wavelength of excitation spectrum of 273 nm and is not suitable for near ultraviolet to blue excitation. Is unsuitable. The phosphor described in Non-Patent Document 3 is a blue-green to yellow-green phosphor, but has an emission spectrum in which a plurality of emission peaks are overlapped, as an alternative to a YAG phosphor having only a yellow emission component. Not suitable for lighting applications.
Furthermore, the YAG phosphor known in Non-Patent Document 4 and the like is based on a garnet structure of Y ₃ Al ₅ O ₁₂ , and its synthesis usually requires a high temperature of 1500 ° C. or higher, and is heat resistant as a firing furnace. It requires high-temperature furnace materials and energy consumption is enormous.

  An object of the present invention is to provide a phosphor having a novel composition that is easy to manufacture and emits yellow to blue light suitable for lighting applications.

  As a result of various studies to achieve the above-mentioned problems, the present inventors have developed a phosphor phosphor having a specific composition containing an alkaline earth metal element, and having a crystalline phase having a specific powder X-ray pattern. It has been found that the phosphor to be contained emits yellow to blue light suitable for lighting applications and can be synthesized without requiring excessive high-temperature firing. The present invention has been accomplished based on these findings.

  That is, the gist of the present invention resides in the following [1] to [8].

[1] A powder X-ray diffraction pattern having a chemical composition represented by the following formula (1), and when three diffraction peaks are selected in descending order of intensity, the three diffraction patterns are selected. The Bragg angle (2θ) indicated by the peak includes crystal phases existing in the ranges of 24.5 ° to 25.5 °, 28.7 ° to 29.7 °, 32.5 ° to 33.5 °, respectively. Phosphor.
M _m P _a O _o : R (1)
(In Formula (1),
M represents a constituent element containing one or more alkaline earth metal elements,
R represents an additive element including one or more luminescent center elements,
m, a and o are respectively
6.3 ≦ m ≦ 7.7
3.6 ≦ a ≦ 4.4
15.3 ≦ o ≦ 18.7
Represents a number that satisfies )

[2] The phosphor according to [1], wherein M further includes one or more Group 12 elements of the periodic table.

[3] The [1] or [2], wherein the emission center element includes one or more elements selected from the group consisting of a rare earth ion emission center, a transition metal ion emission center, and an ns ^{2 type} ion emission center. Phosphor.

[4] Any one of [1] to [3], wherein R includes one or more elements selected from the group consisting of alkali metal elements, Group 13 elements of the periodic table, and Group 14 elements of the periodic table The phosphor described.

[5] The phosphor according to [4], wherein the emission center element is Ce.

[6] The phosphor according to any one of [1] to [5], wherein the emission peak exists in a wavelength range of 460 nm or more and 580 nm or less.

[7] A phosphor-containing composition obtained by dispersing the phosphor according to any one of [1] to [6] in a liquid medium.

[8] A light-emitting device having a first light emitter (excitation light source) and a second light emitter that can convert visible light to light from the first light emitter, The light-emitting device in which this 2nd light-emitting body contains 1 or more types of the fluorescent substance in any one of [1]-[6] as a 1st fluorescent substance.

  According to the present invention, it is possible to provide a phosphor that emits yellow to blue light having a novel elemental composition. This phosphor can be easily synthesized without firing at an excessively high temperature, for example, by firing at a relatively low temperature of about 1200 to 1300 ° C. In addition, since the phosphor of the present invention has a wide half-value width of the emission peak, a combination of the phosphor of the present invention and an LED can provide a light emitting device having excellent color rendering properties and color reproducibility.

It is an X-ray diffraction pattern obtained by powder X-ray diffraction for the phosphor of Comparative Example 1. It is the X-ray-diffraction pattern obtained by powder X-ray diffraction about the fluorescent substance of Example 2-3. 2 is an emission spectrum of the phosphor of Comparative Example 1. 3 is an emission spectrum of the phosphor of Comparative Example 2. It is an emission spectrum of the phosphor of Example 1-11. It is an emission spectrum of the phosphor of Example 2-3.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. Further, in the phosphor composition formula in this specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed separated by commas (,), one or two or more of the listed elements may be included in any combination and composition. For example, the composition formula “(Ca, Sr, Ba) Al ₂ O ₄ : Eu” has “CaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, and “BaAl ₂ O ₄ : Eu”. “Ca _1−x Sr _x Al ₂ O ₄ : Eu”, “Sr _1−x Ba _x Al ₂ O ₄ : Eu”, “Ca _1−x Ba _x Al ₂ O ₄ : Eu”, _{"Ca 1-x-y Sr x} Ba y Al 2 O 4: Eu " (. in the formula, 0 <x <1,0 <y <1,0 < a x + y <1) all the comprehensive It shall be shown in

[1. Phosphor]
<Powder X-ray diffraction pattern of phosphor>
In the phosphor of the present invention, when three diffraction peaks are selected in order from the highest intensity in the powder X-ray diffraction pattern by CuKα rays, the Bragg angle (2θ) indicated by the three diffraction peaks is Crystal phases existing in the ranges of 24.5 ° to 25.5 °, 28.7 ° to 29.7 °, 32.5 ° to 33.5 °, respectively (hereinafter referred to as “crystal phase of the present invention”) Is included).

  That is, the diffraction peak with the highest intensity is called “first peak”, the diffraction peak with the second highest intensity is called “second peak”, the diffraction peak with the third highest intensity is called “third peak”, and the Bragg angle ( 2θ) ranges from 24.5 ° to 25.5 ° as “region A”, ranges from 28.7 ° to 29.7 ° as “region B”, and ranges from 32.5 ° to 33.5 ° as “region A”. When referred to as “region C”, the phosphor of the present invention preferably has any one of the first to third peaks in each of the regions A to C. In particular, the first peak exists in the region C. It is preferable to do. In this case, the second peak exists in one of the regions A and B, and the third peak exists in the other of the regions A and B. Note that diffraction peaks other than the first to third peaks may exist in the regions A to C.

  In order to determine whether or not the crystal phase of the present invention is the above, a powder X-ray diffraction pattern measured using CuKα characteristic X-rays as a radiation source can be generally used. When using a powder X-ray diffraction pattern measured using a source other than the CuKα characteristic X-ray, the powder is converted to a powder X-ray diffraction pattern measured by the CuKα characteristic X-ray, and the crystal phase of the present invention described above is used. It is desirable to determine whether or not. More preferably, the determination can be performed using a powder X-ray diffraction pattern measured under the conditions described below.

The powder X-ray diffraction measurement can be performed with a conventional reflection type concentrated optical system. When measuring the diffraction angle on the low angle side, care should be taken so that the X-ray irradiation width does not exceed the sample width, and measurement is performed using the variable slit mode so that the X-ray irradiation width does not exceed the sample width. It is desirable to correct the intensity after the measurement from the variable slit to the fixed slit.
Specific conditions for powder X-ray diffraction measurement may be performed under the following conditions in addition to those shown in the examples.

Precise measurement is performed with a powder X-ray diffractometer X'Pert Pro MPD (manufactured by PANalytical). The optical system and measurement conditions are as follows.
Optical system: Concentrated optical system Incident side: Enclosed X-ray tube (CuKα)
Soller Slit (0.04 rad)
Divergence Slit (Variable Slit)
Light receiving side: Semiconductor array detector (X'Celerator)
Ni-filter
Soller Slit (0.04 rad)
X-ray output: 40KV, 30mA
Operation axis: θ / 2θ
Scanning range (2θ): 5.0-155.0 °
Measurement mode: Continuous
Reading width: 0.016 ° Counting time: 29.8 sec
Automatic variable slit (Automatic-DS): 10 mm (irradiation width)

  Further, even if crystal phases other than the above-described crystal phase of the present invention are mixed, if the mixed crystal phase is a known phase, it is determined whether or not it is the above-described crystal phase of the present invention according to the following procedure. Can do.

  Powder X-ray diffraction measurement of 2θ = 5 ° to 90 ° is performed, and qualitative analysis (identification operation) of the measured pattern is performed. Excluding the identified diffraction peaks derived from the crystal phase, the remaining diffraction peaks are determined for the presence or absence of the peaks in the above-mentioned regions A to C. In addition, if the diffraction peak derived from the mixed crystal phase does not clearly overlap with the peak in the above-described regions A to C, the presence or absence of the peak in the above-described region A to C in consideration of the diffraction peak derived from the mixed crystal phase. If there is an overlap, peak separation is performed by profile fitting of overlapping peaks, and then the presence / absence of peaks in the above-described regions A to C is determined.

<Composition of phosphor>
The phosphor of the present invention has a chemical composition represented by the following formula (1), and preferably the above-described crystal phase of the present invention has a chemical composition represented by the following formula (1).
M _m P _a O _o : R (1)
(In Formula (1),
M represents a constituent element containing one or more alkaline earth metal elements,
R represents an additive element including one or more luminescent center elements,
m, a and o are respectively
6.3 ≦ m ≦ 7.7
3.6 ≦ a ≦ 4.4
15.3 ≦ o ≦ 18.7
Represents a number that satisfies )
That is, the phosphor of the present invention preferably contains the crystal phase of the present invention having a chemical composition represented by the above formula (1).

In the above formula (1), “M” represents a constituent element including an alkaline earth metal element such as Mg, Ca, Sr, or Ba. The M element may contain two or more alkaline earth metal elements. The M element preferably contains at least one of Ca, Sr, and Ba, more preferably contains Ca and Ba, and further preferably contains Ca. It is particularly preferable that the M element includes Ca and Ba as follows.
The M element may further contain Group 12 elements of the periodic table such as Zn and Cd. The M element may contain two or more Group 12 elements of the periodic table.

  The proportion of Ca to the entire M element is preferably 70 mol% or more, more preferably 75 mol% or more, and particularly preferably 80 mol% or more. Further, the ratio of Ca to the entire M element is preferably 100% or less, more preferably 95% or less, and particularly preferably 90% or less.

  In addition to Ca, the M element preferably further contains an alkaline earth metal such as Sr or Ba and / or a periodic table group 12 element such as Zn or Cd, and more preferably contains Ba. In this case, the proportion of the alkaline earth metal other than Ca and / or Group 12 element of the periodic table with respect to the whole M element is preferably 10 mol% or more and 25 mol% or less, and 13 mol% or more and 22 mol%. % Or less is preferable.

In the formula (1), “R” represents an additive element including one or more luminescent center elements. As the luminescent center element acting as an activator, ions called Ce ³⁺ , Pr ³⁺ , Nd ³⁺ , Sm ³⁺ , Eu ³⁺ , Gd ³⁺ , Tb ³⁺ , Dy ³⁺ , Ho ³⁺ , Er ³⁺ , which are called rare earth ion luminescent centers, Tm ³⁺ , Yb ³⁺ , Sm ²⁺ , Eu ²⁺ , Yb ²⁺ ; Cr ³⁺ , Mn ⁴⁺ , Mn ²⁺ , Fe ³⁺ , ions called transition metal ion emission centers; Sn ^2+, an ion called ns ^{2 type} ion emission centers , Sb ³⁺ , Tl ⁺ , Pb ²⁺ , and Bi ³⁺ preferably contain at least one element that can be an ion. As the luminescent center element, it is more preferable to include rare earth elements such as Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Sm, Eu, and Yb. More preferably, Ce and / or Eu is contained in view of efficiency.

Further, the R element in the formula (1) may contain one or more elements selected from the group consisting of alkali metal elements, group 13 elements of the periodic table, and group 14 elements of the periodic table in addition to the luminescent center element. preferable. These can be used as appropriate in order to maintain the charge balance of the entire phosphor. In particular, when Ce is included as the luminescent center element, the effect of suppressing defects can be expected by maintaining the charge balance. Is preferably used. In addition, the emission color can be adjusted by including these elements.
In the following, the emission center element contained in the R element is represented by “Rx”, and among the elements other than the emission center element contained in the R element, the alkali metal element is represented by “Ry”. An element selected from Group 14 elements may be represented by “Rz”.

  Examples of R elements other than the emission center element include alkali metal elements such as Li, Na, K, and Cs; periodic table group 13 elements such as B, Al, Ga, In, and Tl; and C, Si, Ge, and the like The periodic table group 14 element is preferred. In particular, when the emission center element is Ce, the R element contained in addition to the emission center element is an alkali metal element such as Li, Na, K, or Cs; and a periodic table such as B, Al, Ga, In, or Tl. By including a Group 13 element; and a Group 14 element of the periodic table such as C, Si, Ge, etc., the charge balance in the entire crystal structure can be maintained, which is preferable.

The ratio of the luminescent center element to the entire R element is preferably 30 mol% or more, more preferably 40 mol% or more, and particularly preferably 50 mol% or more. The ratio of additive elements other than the luminescent center element to the entire R element is preferably 50 mol% or less.
When the luminescent center element is Ce, the ratio of Ce to the entire R element is preferably 30 mol% or more, particularly 40 mol% or more, and 80 mol% or less, particularly 70 mol% or less.
When the luminescent center element is Eu, the ratio of Eu to the entire R element may be 100 mol%.

  Note that the R element is incorporated into the crystal structure by being replaced with the M element or the P element. Specifically, the luminescent center element Rx is substituted into the M element and introduced into the crystal structure. Among the R elements contained other than the luminescent center element, alkali metal elements such as Li, Na, K, and Cs, which are Ry elements, are substituted into the M element and introduced into the crystal structure. On the other hand, among the R elements contained other than the luminescent center element, periodic table group 13 elements such as B, Al, Ga, In and Tl which are Rz elements; and periodic table group 14 such as C, Si and Ge The element is substituted into the P element and introduced into the crystal structure.

In the formula (1), “P” is phosphorus.
In the formula (1), “O” represents oxygen. The O element only needs to contain oxygen as a main component, and may contain F, Cl, or the like within a range that does not affect the characteristics of the obtained phosphor.

  Further, the phosphor of the present invention includes, in addition to the above-described constituent elements of M, R, P, and O, elements that are inevitably mixed within a range that does not affect the effects of the present invention, such as impurity elements. Etc. may be included.

In the above formula (1), “m” is the sum of molar ratios of M element (alkaline earth metal element and / or periodic table group 12 element) and R element (Rx element and Ry element) substituted for M element. Show. m is a number that usually satisfies 6.3 ≦ m ≦ 7.7, preferably 6.4 or more, more preferably 6.6 or more, particularly preferably 6.8 or more, and preferably 7. It is 6 or less, more preferably 7.4 or less, and particularly preferably 7.2 or less.
The substitution rate of R element (Rx element and Ry element) in M element is preferably 0.1 mol% to 15 mol% with respect to m.

In the formula (1), “a” represents the sum of the molar ratios of the P element (phosphorus) and the R element (Rz element) that substitutes for the P element. a is a number satisfying 3.6 ≦ a ≦ 4.4, preferably 3.7 or more, more preferably 3.8 or more, particularly preferably 3.9 or more, and preferably 4.3. Hereinafter, it is more preferably 4.2 or less, and particularly preferably 4.1 or less.
The substitution rate of R element (Rz element) in P element is preferably 0.1 mol% to 15 mol% with respect to a.

  In said Formula (1), "o" shows the molar ratio of O element (oxygen). o is a number satisfying 15.3 ≦ o ≦ 18.7, preferably 15.8 or more, more preferably 16.3 or more, further preferably 16.8 or more, and preferably 18.2. Hereinafter, it is more preferably 17.7 or less, and still more preferably 17.2 or less.

More specifically, the formula (1) is represented by the following formula (1A), and preferably satisfies one or both of the following formulas (1a) and (1b).
M _(mx-y) P _(az) Rx _x Ry _y Rz _z O _o (1A)
6.3 ≦ m ≦ 7.7
3.6 ≦ a ≦ 4.4
15.3 ≦ o ≦ 18.7
0 ≦ x ≦ 1.0
0 ≦ y ≦ 2.0
0 ≦ z ≦ 2.0
0.001 m ≦ x + y ≦ 0.15 m (1a)
0.001a ≦ z ≦ 0.15a (1b)

<Characteristics of phosphor>
(Peak emission wavelength)
The emission peak wavelength of the phosphor of the present invention varies depending on the type of the emission center element Rx contained in R. For example, the phosphor of the present invention when Ce is used as the emission center element Rx is usually 430 nm or more, preferably The emission peak is 440 nm or more, more preferably 450 nm or more, particularly preferably 460 nm or more, and usually has an emission peak in a wavelength range of 520 nm or less, preferably 510 nm or less, more preferably 500 nm or less. That is, it has a blue-green light emission color.
Further, the phosphor of the present invention when Eu is used as the emission center element Rx is usually 510 nm or more, preferably 520 nm or more, more preferably 530 nm or more, particularly preferably 540 nm or more, and usually 590 nm or less, preferably Has an emission peak in a wavelength range of 580 nm or less, more preferably 570 nm or less. That is, it has a yellow emission color.

(Half width of emission spectrum)
In the phosphor of the present invention, the half width of the emission peak is usually 60 nm or more, preferably 70 nm or more, more preferably 80 nm or more, and particularly preferably 90 nm or more. That is, it shows an emission spectrum with a wide half-value width.
Since the phosphor of the present invention has a wide half-value width of the emission peak, when used in combination with a blue LED, light emission with good color rendering can be obtained with only one type of phosphor. In addition to the phosphor of the present invention, if a light emitting device is formed by combining a blue to yellow-green phosphor, a red phosphor, or the like, a light emitting device that emits light of higher color rendering can be obtained.

(Particle size)
The phosphor of the present invention usually has a fine particle form. Specifically, the mass median diameter _{D 50} is usually 2μm or more, preferably 5μm or more, and usually 30μm or less, preferably fine particles of the range 20 [mu] m. When the mass median diameter D ₅₀ is too large, for example, tend to dispersibility becomes poor in the liquid medium in the preparation of which will be described later phosphor-containing composition tends to be too small and the low luminance.

Mass median diameter D ₅₀ is, for example, obtained by measuring particle size distribution by laser diffraction scattering method, is a value determined from the mass-standard particle size distribution curve. The median diameter D ₅₀ is in this mass-standard particle size distribution curve, the accumulated value refers to the particle size value when the 50%.

[2. Method for producing phosphor]
In the phosphor of the present invention, each phosphor material is weighed so as to have the composition of the crystal phase represented by the formula (1) to prepare a phosphor material mixture, and the obtained phosphor material mixture is fired. Can be manufactured.

  As the phosphor material, a metal compound, a metal, or the like is used. For example, when producing the phosphor of the present invention having a crystal phase having the composition represented by the formula (1), a raw material of M element (hereinafter referred to as “M source” as appropriate) and a raw material of P element (hereinafter referred to as “P” as appropriate). Source)), a necessary combination from the raw material of R element (hereinafter referred to as “R source” as appropriate) (mixing step), the obtained mixture is fired (firing step), and the obtained fired product is necessary. Depending on the condition, it can be produced by crushing, grinding or washing (post-treatment process). Note that the raw material of the O element is mainly supplied from oxygen contained in the M source, the P source, and the R source.

<Phosphor material>
As the phosphor raw material used, known materials can be used, for example, Ba sources such as Ba ₃ N ₂ , BaHPO ₄ , BaO, BaCO _3, etc. as M sources, Ca ₃ N ₂ , CaHPO ₄ , CaO, CaCO ₃ or the like Ca _{source, Sr 3 N 2, SrHPO 4} , SrO, SrCO 3 , etc. Sr _{source, Mg 3 N 2, MgHPO 4} , MgO, MgCO Mg source such as _3, Zn source such as ZnO; as R source Ce source such as Ce compound selected from Ce metal, oxide, carbonate, chloride, fluoride, nitride or oxynitride, Eu metal, oxide, carbonate, chloride, fluoride, nitride Eu sources (hereinafter referred to as Rx sources) such as Eu compounds selected from oxides or oxynitrides, Si sources such as SiC, Si ₃ N ₄ and SiO ₂ , Al sources such as AlN and Al ₂ O ₃ , H ₃ BO ₃ , B such as B ₂ O ₃ The source (or Rz source), LiCO Li source such as _3, Na source such _Na 2 CO _3, K K source such as 2 CO _3, Cs source such _Cs 2 CO ₃ (or more Ry source); NH as P source ₄ H ₂ PO ₄ , (NH ₄ ) ₃ PO ₄ , (NH ₄ ) ₂ HPO _4, or the like can be used.

The O source (oxygen) in the formula (1) may be supplied from a P source, an M source, or an R source, or may be supplied from a firing atmosphere. The P source may also be supplied from an M source such as CaHPO ₄ or BaHPO ₄ . Each raw material may contain inevitable impurities.

<Mixing process>
The phosphor raw materials are weighed so as to obtain the target composition, and sufficiently mixed using a ball mill or the like to obtain a phosphor raw material mixture (mixing step).

Although it does not specifically limit as said mixing method, Specifically, the method of following (A) and (B) is mentioned.
(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., or pulverization using mortar and pestle, and mixer such as ribbon blender, V-type blender, Henschel mixer, or mortar and pestle And a dry mixing method in which the above phosphor raw materials are pulverized and mixed.

  (B) A solvent or dispersion medium such as water is added to the phosphor material described above, and mixed using, for example, a pulverizer, a mortar and a pestle, or an evaporating dish and a stirring rod, to obtain a solution or slurry. A wet mixing method in which drying is performed by spray drying, heat drying, or natural drying.

  The mixing of the phosphor raw material may be either the wet mixing method or the dry mixing method, but in order to avoid contamination of the phosphor raw material with moisture, a dry mixing method or a wet mixing method using a water-insoluble solvent is more preferable. .

<Baking process>
Subsequently, the phosphor material mixture obtained in the mixing step is fired (firing step).
For example, the phosphor raw material mixture described above is dried as necessary and then filled into a container such as a crucible and fired using a firing furnace, a pressure furnace, or the like.
Preferred conditions in the firing step are described below.

  Examples of the material of the firing container (such as a crucible) used in the firing step include alumina, boron nitride, and carbon. Among these, it is preferable to use an alumina product because a phosphor having good crystallinity can be obtained.

  Although the firing temperature varies depending on other conditions such as pressure, firing can usually be performed in a temperature range of 1000 ° C. or higher and 2100 ° C. or lower. The maximum temperature reached in the firing step is usually 1000 ° C. or higher, preferably 1100 ° C. or higher, and is usually 2100 ° C. or lower, preferably 1900 ° C. or lower, more preferably 1700 ° C. or lower, more preferably 1600 ° C. or lower, especially Preferably it is 1500 degrees C or less. If the firing temperature is too high, nitrogen contained in the raw material will fly and defects will be generated in the host crystal, making it easy to color, and impurities tend to be generated. If it is too low, the progress of the solid phase reaction tends to be slow. In particular, for the purpose of the present invention to synthesize phosphors with reduced energy consumption without requiring a high heat-resistant firing furnace, the firing temperature is preferably 1400 ° C. or lower. In this way, the target phosphor can be produced even at a relatively low firing temperature.

  The heating rate in the firing step is usually 2 ° C./min or more, preferably 5 ° C./min or more, more preferably 10 ° C./min or more, and usually 30 ° C./min or less, preferably 25 ° C./min or less. It is. If the rate of temperature rise is below this range, the firing time may be long. In addition, if the rate of temperature rise exceeds this range, the firing device, container, etc. may be damaged.

  The firing atmosphere in the firing step is arbitrary as long as the phosphor of the present invention is obtained, but a nitrogen gas-containing atmosphere is preferable. Specific examples include a nitrogen gas atmosphere, a hydrogen-containing nitrogen gas atmosphere, and the like, and among them, a hydrogen-containing nitrogen gas atmosphere is preferable. The oxygen content in the firing atmosphere is usually 10 ppm or less, preferably 5 ppm or less.

  The firing time (baking temperature holding time) varies depending on the temperature and pressure during firing, but is usually 10 minutes or longer, preferably 30 minutes or longer, and usually 24 hours or shorter, preferably 12 hours or shorter.

  Although the pressure in the firing step varies depending on the firing temperature and the like, the pressure in the furnace can be set to atmospheric pressure (0.1013 MPa) or a pressurized state. The pressure in the firing step is usually 0.1013 MPa or more, and is usually 100 MPa or less, preferably 50 MPa or less, more preferably 20 MPa or less, and particularly preferably 10 MPa or less. The phosphor of the present invention is preferable because it can be produced usually under atmospheric pressure, that is, at atmospheric pressure, and can be easily produced.

  In addition, you may repeat a baking process in multiple times as needed. In that case, the firing conditions may be the same or different between the first firing and the second firing.

(Post-processing process)
The fired product obtained by firing becomes granular or massive. This is pulverized, pulverized and / or classified into a powder of a predetermined size. _Here, it is preferable to process as _{D 50} is less than about 30 [mu] m.

  As an example of the specific treatment, the baked product is subjected to a sieve classification process with an opening of about 45 μm, and the powder that has passed through the sieve is passed to the next process, or the baked product is used in a general method such as a ball mill, a vibration mill, or a jet mill. The method of grind | pulverizing to a predetermined particle size using a grinder is mentioned. In the latter method, excessive pulverization not only generates fine particles that easily scatter light, but also generates crystal defects on the particle surface, which may cause a decrease in luminous efficiency.

  Moreover, you may provide the process of wash | cleaning fluorescent substance (baked material) as needed. After the cleaning step, the phosphor is dried until it has no adhering moisture and is used. Further, if necessary, dispersion / classification treatment may be performed to loosen the aggregation.

[3. Use of phosphor]
The phosphor of the present invention can be used for any application using the phosphor. In addition, the phosphor of the present invention can be used alone, but two or more kinds of phosphors can be used together, or a phosphor mixture of any combination using the phosphor of the present invention and other phosphors in combination. Can also be used.

The phosphor of the present invention can be used as a phosphor-containing composition by mixing with a known liquid medium (for example, a silicone compound).
In addition, the phosphor obtained by the present invention can be suitably used for various light-emitting devices by combining with a light source that emits ultraviolet light, taking advantage of the property that it can be excited by ultraviolet light.

  The emission color of the light-emitting device is not limited to purple or white, but by appropriately selecting the combination and content of phosphors, light emission that emits light in any color, such as light bulb color (warm white) or pastel color The device can be manufactured. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

[4. Phosphor-containing composition]
The phosphor of the present invention can be used by mixing with a liquid medium. In particular, when the phosphor of the present invention is used for applications such as a light emitting device, it is preferably used in a form dispersed in a liquid medium. The phosphor of the present invention dispersed in a liquid medium will be referred to as “the phosphor-containing composition of the present invention” as appropriate.

<Phosphor>
There is no restriction | limiting in the kind of fluorescent substance of this invention contained in the said fluorescent substance containing composition, It can select arbitrarily. Moreover, the fluorescent substance of this invention contained in a fluorescent substance containing composition may be only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Furthermore, the phosphor-containing composition may contain a phosphor other than the phosphor of the present invention as long as the effects of the present invention are not significantly impaired.

<Liquid medium>
The kind of the liquid medium used for the phosphor-containing composition of the present invention is not particularly limited, and a curable material that can be molded over the semiconductor light emitting element can be used. The curable material is a fluid material that is cured by performing some kind of curing treatment. Here, the fluid state means, for example, a liquid state or a gel state. The curable material is not particularly limited as long as it secures the role of guiding the light emitted from the solid light emitting element to the phosphor. Moreover, only 1 type may be used for a curable material and it may use 2 or more types together by arbitrary combinations and a ratio. Therefore, as the curable material, any of inorganic materials, organic materials, and mixtures thereof can be used.

<Content of liquid medium and phosphor>
The content of the liquid medium of the phosphor-containing composition of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 25% by mass or more, preferably with respect to the entire phosphor-containing composition of the present invention. Is 40% by mass or more, and is usually 99% by mass or less, preferably 95% by mass or less, more preferably 80% by mass or less. When the amount of the liquid medium is large, no particular problem occurs. However, in order to obtain a desired chromaticity coordinate, color rendering index, luminous efficiency, etc. in the case of a semiconductor light emitting device, it is usually at a blending ratio as described above. It is desirable to use a liquid medium. On the other hand, when there is too little liquid medium, fluidity | liquidity may fall and it may become difficult to handle.

  The phosphor content in the phosphor-containing composition of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 1% by mass or more with respect to the entire phosphor-containing composition of the present invention, Preferably it is 5 mass% or more, More preferably, it is 20 mass% or more, and is 75 mass% or less normally, Preferably it is 60 mass% or less. The proportion of the phosphor of the present invention in the phosphor in the phosphor-containing composition is also arbitrary, but is usually 30% by mass or more, preferably 50% by mass or more, and usually 100% by mass or less. If the phosphor content in the phosphor-containing composition is too high, the flowability of the phosphor-containing composition may be inferior and difficult to handle, and if the phosphor content is too low, the light emission efficiency of the light-emitting device decreases. There is a tendency.

<Other ingredients>
In the phosphor-containing composition of the present invention, in addition to the phosphor and the liquid medium, other components such as a metal oxide for adjusting the refractive index, a diffusing agent, and a filler are used unless the effects of the present invention are significantly impaired. Further, additives such as a viscosity modifier and an ultraviolet absorber may be contained. Only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

[5. Light emitting device]
A light-emitting device of the present invention includes a first light-emitting body (excitation light source) and a second light-emitting body that can emit visible light by converting light from the first light-emitting body into visible light. The above-mentioned [1. It contains a first phosphor containing one or more of the phosphors of the present invention described in the section [Phosphor].

  Preferable specific examples of the phosphor of the present invention used in the light emitting device of the present invention include [1. Examples thereof include the phosphor of the present invention described in the “Phosphor” column and the phosphors used in the respective Examples in the “Example” column described later. In addition, any one of the phosphors of the present invention may be used alone, or two or more may be used in any combination and ratio.

  The light-emitting device of the present invention has a first light emitter (excitation light source), and at least the phosphor of the present invention is used as the second light emitter. It is possible to arbitrarily adopt the apparatus configuration.

Among the light emitting devices of the present invention, in particular, the white light emitting device is specifically a first light emitter, generally a semiconductor light emitting element, specifically a light emitting diode (LED) or a laser diode (LD). In addition to the phosphor of the present invention, a phosphor emitting blue fluorescence, a phosphor emitting green fluorescence, a phosphor emitting red fluorescence, a phosphor emitting yellow fluorescence, and the like. It can be obtained by using any combination of phosphors and taking a known apparatus configuration.
Here, the white color of the white light emitting device means all of (yellowish) white, (greenish) white, (blueish) white, (purple) white and white defined by JIS Z 8701 Of these, white is preferred.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In addition, the values of various production conditions and evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is the value of the upper limit or the lower limit. It may be a range defined by a combination of values of the following examples or values of the examples.

[Examples 1-1 to 1-17, 2-1 to 2-11 and Comparative Examples 1 to 2]
As a raw material compound of the phosphor, CaCO ₃ (manufactured by Hakuho Chemical Laboratory, purity 99.9%), SrCO ₃ (manufactured by Hakuho Chemical Laboratory, purity 99.9%), CaHPO ₄ (manufactured by Alfa Aesar, purity) 98%), CeO ₂ (manufactured by Alfa Aesar, purity 99.9%), Eu ₂ O ₃ (manufactured by Alfa Aesar, purity 99.99%), BaCO ₃ (manufactured by Alfa Aesar, purity 99.8%), SiO ₂ (Manufactured by Tatsumori, purity 99.9%), MgO (manufactured by Alfa Aesar, purity 99.95%), ZnO (manufactured by Acros, purity 99.5%), Li ₂ CO ₃ (manufactured by Alfa Aesar, purity 99.998) %), Al ₂ O ₃ (manufactured by Alfa Aesar, purity 99.997%), H ₃ BO ₃ (manufactured by Sigma-Aldrich, purity 99.5%), Na ₂ CO ₃ (manufactured by Fisher Scientific, purity 99.5%), K ₂ CO ₃ (manufactured by Fisher Scientific, purity 99%), and Cs ₂ CO ₃ (manufactured by Sigma-Aldrich, 99.95%) were used.

The phosphor was synthesized as follows.
The raw material compounds were weighed with the weights shown in Table 2 so as to have the composition formula shown in Table 1. The weighed raw material compounds were mixed and stirred in ethanol for 5 minutes using an agate pestle and an agate mortar, then transferred to an alumina crucible (purity 99%), and then the alumina crucible was put into a tubular furnace (Elite TSH 15/75/450). installed. A reducing gas of 0.1 liter / min was allowed to flow there. As the reducing gas, a mixed gas of 5% by volume H ₂ and 95% by volume N ₂ was used.

In Comparative Examples 1 and 2 and Examples 1-1 to 1-9 and 2-7 to 2-11, the temperature rise was 4 ° C./min from 150 ° C. to 400 ° C., and 8 ° C./min from 400 ° C. to 1250 ° C. Went in minutes. Thereafter, it was held at 1250 ° C. (maximum temperature reached) under normal pressure for 10 hours. Cooling was performed from 1250 ° C. to 150 ° C. at 8 ° C./min.
Thereafter, the fired product was taken out into the room, and the fired product was pulverized in the air using an alumina pestle and an alumina mortar to obtain a phosphor.

  In Examples 1-10 to 1-17, the maximum attained temperature was maintained at 1350 ° C. under normal pressure for 10 hours, and in Examples 2-1 to 2-6, the maximum achieved temperature was maintained at 1300 ° C. under normal pressure for 10 hours. Obtained phosphors in the same manner as in Comparative Examples 1 and 2 and Examples 1-1 to 1-9 and 2-7 to 2-11.

  Comparative Example 1 is a phosphor without Ce activated Ba, Examples 1-1 to 1-17 are phosphors with Ce activated Ba, and Comparative Example 2 is Eu activated Ba. The phosphors that do not have, Examples 2-1 to 2-11, are phosphors that have Ba activated with Eu.

About the obtained fluorescent substance, the powder X-ray pattern analysis was performed with the following method. Powder X-ray diffraction was precisely measured with a powder X-ray diffractometer D8 ADVANCE manufactured by Bruker. The measurement conditions are as follows.
・ CuKα tube used ・ X-ray output: 40KV, 40mA
・ Divergent slit: 0.25 °
・ Detector: 1D position sensitive streamer mode counter ・ Scanning range (2θ): 10 ° to 70 °
・ Reading width: 0.04 °
・ Counting time: 0.1 to 2 seconds

The phosphors obtained in Examples 1-1 to 1-17 and 2-1 to 2-11 and Comparative Examples 1 and 2 were each provided with a 450 W xenon lamp as an excitation light source, and photomultiplier as a spectrum measurement device. Using a modular fluorescence spectrometer SPEX Fluorolog-3 (manufactured by HORIBA, Ltd.) equipped with a tube R928 (manufactured by Hamamatsu Photonics), the emission peak intensity in the wavelength range of 410 to 800 nm was measured.
Specifically, the light from the excitation light source was passed through a diffraction grating spectrometer having a focal length of 32 cm, and only the excitation light having a wavelength of 400 nm was irradiated onto the phosphor. The light generated from the phosphor by the irradiation of excitation light is dispersed by a diffraction grating spectrometer, the emission intensity of each wavelength is measured by a spectrum measuring device in the wavelength range of 410 nm to 800 nm, and signal processing such as sensitivity correction by a personal computer After that, an emission spectrum was obtained. At the time of measurement, the measurement was performed with the slit width of the light-receiving side spectrometer set to 1 nm. In Comparative Example 1, an emission spectrum was obtained with a wavelength of excitation light of 365 nm, and in Comparative Example 2 with a wavelength of excitation light of 465 nm.

In addition, with respect to the phosphors obtained in Examples 1-1 to 1-17, 2-1 to 2-11, and Comparative Examples 1-2, the wavelength region of 360 nm to 800 nm of the emission spectrum obtained by the above-described method. From the above data, the chromaticity coordinates of the x, y color system (CIE 1931 color system) are calculated as the chromaticity coordinates x and y in the XYZ color system defined by JIS Z8701 by a method according to JIS Z8724. did.
Tables 3 and 4 show the measurement results of the emission peak wavelength, relative peak intensity, half width, and chromaticity coordinates (CIEx, CIEy) in the emission spectrum. In Tables 3 and 4, the composition formulas of the respective phosphors (same as those shown in Table 1) are shown.

The phosphor of Comparative Example 1 did not emit light when irradiated with excitation light having a wavelength of 400 nm, but the phosphors of Examples 1-1 to 1-17 showed strong light emission. Examples 1-4 to 1-9 and Example 1-11 in which Si was introduced as the R element showed particularly strong light emission.
Further, the phosphor of Comparative Example 2 showed only weak light emission when irradiated with excitation light having a wavelength of 400 nm, but the phosphors of Examples 2-1 to 2-11 showed strong light emission.

  FIG. 3 shows the emission spectrum of the phosphor of Comparative Example 1, FIG. 4 shows the emission spectrum of the phosphor of Comparative Example 2, FIG. 5 shows the emission spectrum of the phosphor of Example 1-11, and FIG. The emission spectrum of the phosphor is shown in FIG. The phosphors of Examples 1-1 to 1-10 and 1-12 to 1-17 show the same spectral shape as the phosphor of Example 1-11, and Examples 2-1, 2-2, 2- The phosphors of 4 to 2-11 showed the same spectral shape as the phosphor of Example 2-3.

  1 shows the X-ray diffraction pattern of the phosphor obtained in Comparative Example 1, and FIG. 2 shows the X-ray diffraction pattern of the phosphor obtained in Example 2-3. The phosphor of Comparative Example 2 shows the same X-ray diffraction pattern as the phosphor of Comparative Example 1, and Examples 1-1 to 1-17, 2-1, 2-2, 2-4 to 2-11. The phosphor showed almost the same X-ray diffraction pattern as that of Example 2-3.

  From the X-ray diffraction pattern of FIG. 2, the phosphors of Examples 1-1 to 1-17 and Examples 2-1 to 2-11 are both in the region C of 2θ = 32.5 ° to 33.5 °. The first peak with the highest intensity exists in the region A, and the second peak with the second highest intensity or the third peak with the third highest intensity exists in the region A of 2θ = 24.5 ° to 25.5 °. It can be seen that a second peak with the second highest intensity or a third peak with the third highest intensity exists in the region B of 2θ = 28.7 ° to 29.7 °.

Since the obtained X-ray diffraction pattern was not identified by searching the PDF database, a limited-field electron diffraction image was measured by Philips CM30 TEM, and as a result of the analysis, the crystal system and unit cell were estimated as follows. It was.
Monoclinic system, a = 11.98Å, b = 6.93Å, c = 11.42Å, β = 134.2 °

  As a result of Le Bail fitting based on the lattice information estimated above, it was found that the space group was C2 / m.

  Moreover, about the fluorescent substance of Example 2-3, as a result of having observed SEM-ED by JEOL 5800LV microscope, the ratio with respect to the sum total of Ca of Ca and Ba was estimated to be about 16-17 mol%. This corresponds to Ca: Ba = 6: 1 (molar ratio).

From the refined lattice constant, the integrated intensity of the X-ray diffraction pattern was extracted, and using these values and the direct method program, approximate fractional coordinates in the unit lattice of this unknown structural substance were obtained. Using the obtained fraction coordinates, the Rietveld method fraction coordinates were refined from the X-ray diffraction pattern data, and the results shown in Table 5 below were obtained. The final refined lattice constant is as follows.
Space C2 / m (No. 12), a = 12.3303 mm, b = 7.104 mm, c = 11.716 mm, β = 134.442 °

As a result of the above analysis, it can be confirmed that the obtained base crystal is Ca ₆ BaP ₄ O ₁₇ , which is a new crystal phase not registered in the ICDD database generally used for X-ray diffraction. It was confirmed that.

  The phosphor of the present invention can be used in any field where light is used. For example, in addition to indoor and outdoor lighting, image display of various electronic devices such as mobile phones, household appliances, and outdoor installation displays. It can be suitably used for an apparatus or the like.

Claims (8)

When three diffraction peaks having the chemical composition represented by the following formula (1) are selected in order from the highest in the powder X-ray diffraction pattern by CuKα rays, the three diffraction peaks are shown. A phosphor comprising a crystal phase having a Bragg angle (2θ) in the range of 24.5 ° to 25.5 °, 28.7 ° to 29.7 °, and 32.5 ° to 33.5 °, respectively.
M _m P _a O _o : R (1)
(In Formula (1),
M represents a constituent element containing one or more alkaline earth metal elements,
R represents an additive element including one or more luminescent center elements,
m, a and o are respectively
6.3 ≦ m ≦ 7.7
3.6 ≦ a ≦ 4.4
15.3 ≦ o ≦ 18.7
Represents a number that satisfies )   The phosphor according to claim 1, wherein the M further contains one or more Group 12 elements of the periodic table. The luminescence center element, rare earth ions luminescence center, transition metal ion emission center, and ns containing at least one element selected from the group consisting of ² form ion luminescence center, phosphor according to claim 1 or 2.   The fluorescence according to any one of claims 1 to 3, wherein R includes one or more elements selected from the group consisting of alkali metal elements, Group 13 elements of the periodic table, and Group 14 elements of the periodic table. body.   The phosphor according to claim 4, wherein the luminescent center element is Ce.   The phosphor according to any one of claims 1 to 5, wherein the emission peak exists in a wavelength range of 460 nm or more and 580 nm or less.   A phosphor-containing composition comprising the phosphor according to any one of claims 1 to 6 dispersed in a liquid medium.   A light emitting device having a first light emitter (excitation light source) and a second light emitter capable of emitting visible light by converting light from the first light emitter, the second light emitter. The light-emitting device containing 1 or more types of the fluorescent substance of any one of Claims 1-6 as a 1st fluorescent substance.

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