JP2023049445A - Phosphor, production method of the same, and light emitting device - Google Patents

Abstract

To provide a phosphor emitting green light with higher emission intensity.SOLUTION: A phosphor includes a first oxide containing Rb, Na, Li, Eu and Si in its composition. The first oxide has a composition in which a molar ratio of Rb to Si is 0.5 or more and less than 1, that of Na to Si is more than 0 and less than 0.5, that of Li to Si is more than 2 and less than 3.5, and that of a sum total content of Na and Li to Rb is 3 or more and 7 or less. In an X-ray diffraction pattern using a CuKα ray, the phosphor has a first diffraction peak in a Bragg angle range of 15.5° or more and 16.5° or less and a second diffraction peak in a Bragg angle range of 11.0° or more and 12.0° or less. When an intensity ratio of the second diffraction peak to the first diffraction peak is set to be α, α is in a range of 0.6 or more and 1.6 or less.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present disclosure relates to phosphors, methods of manufacturing the same, and light emitting devices.

In order to widen the range of color reproducibility, a green-emitting phosphor having an emission spectrum with a narrower wavelength width may be used in a light-emitting device used as a backlight for a display device. For example, Patent Document 1 describes a lithium orthosilicate phosphor as a phosphor emitting green light.

Japanese Patent Publication No. 2019-527760

As a green-emitting phosphor, a phosphor with higher emission intensity is desired, and an object of one embodiment of the present disclosure is to provide a green-emitting phosphor with higher emission intensity.

A first aspect is a phosphor containing a first oxide containing Rb, Na, Li, Eu and Si in its composition. In the first oxide, the molar ratio of Rb to Si is 0.5 or more and less than 1, the molar ratio of Na to Si is greater than 0 and less than 0.5, and the molar ratio of Li to Si is greater than 2. less than 3.5, and the molar ratio of the total content of Na and Li to Rb is 3 or more and 7 or less. In the X-ray diffraction (XRD) pattern using CuKα rays, the phosphor has a first diffraction peak within the range of 15.5° or more and 16.5° or less of Bragg angle and a Bragg angle of 11.0° or more. and a second diffraction peak within the range of 0° or less, where α is the intensity ratio of the second diffraction peak to the first diffraction peak, and the α is in the range of 0.6 or more and 1.6 or less is.

A second aspect includes a phosphor of the first aspect and a fluorescent member including a first phosphor having an emission peak wavelength in the range of 525 nm or more and 535 nm or less, and an emission peak wavelength in a wavelength range of 380 nm or more and 470 nm or less. and a light emitting device.

A third aspect is a phosphor production method including heat-treating a raw material mixture containing an Rb source, a Na source, a Li source, an Eu source and a Si source at a temperature within the range of 400° C. or higher and 800° C. or lower. . The raw material mixture has a molar ratio of Rb to Si of 0.5 or more and less than 1, a molar ratio of Na to Si of more than 0 and less than 0.5, and a molar ratio of Li to Si of more than 2 to 3. The molar ratio of Eu to Si is greater than 0 and less than 0.3, and the molar ratio of the total content of Na and Li to Rb is 3 or more and 7 or less. At least one of the Rb source, Na source, Li source, Eu source and Si source contained in the raw material mixture contains an oxide.

According to one aspect of the present disclosure, it is possible to provide a green-emitting phosphor with higher emission intensity.

It is a schematic sectional drawing which shows an example of a light-emitting device. 4 is a graph showing the relationship between the XRD peak intensity ratio and the relative emission energy. 4 is a graph showing the relationship between the XRD peak intensity ratio and the emission peak wavelength. 4 is XRD spectra according to Examples and Comparative Examples.

In this specification, the term "process" is not only an independent process, but even if it cannot be clearly distinguished from other processes, it is included in this term as long as the intended purpose of the process is achieved. . In addition, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. Furthermore, the upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined. In this specification, multiple elements described separated by commas (,) in the formulas representing the composition of the phosphor or light-emitting material indicate that at least one of these multiple elements is included in the composition. means to contain Further, in the formulas representing the composition of the phosphor, before the colon (:) represents the host crystal, and after the colon (:) represents the activating element. In this specification, the relationship between color names and chromaticity coordinates, the relationship between wavelength ranges of light and color names of monochromatic light, etc. conform to JIS Z8110. The half width of the phosphor means the wavelength width (full width at half maximum; fwhm) of the emission spectrum at which the emission intensity is 50% of the maximum emission intensity in the emission spectrum of the phosphor. Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments shown below exemplify the phosphor, the method for producing the same, and the light-emitting device for embodying the technical idea of the present invention. It is not limited to methods and light emitting devices.

Phosphor The phosphor includes a first oxide containing Rb, Na, Li, Eu and Si in its composition. In the first oxide, the molar ratio of Rb to Si is 0.5 or more and less than 1, the molar ratio of Na to Si is greater than 0 and less than 0.5, and the molar ratio of Li to Si is greater than 2 and less than 3. .5 and the molar ratio of the total content of Na and Li to Rb is 3 or more and 7 or less. In the X-ray diffraction pattern using CuKα rays, the phosphor has a first diffraction peak in the range of 15.5° or more and 16.5° or less and a Bragg angle of 11.0° or more and 12.0° It has a second diffraction peak within the following range, and the intensity ratio of the second diffraction peak to the first diffraction peak is within the range of 0.6 or more and 1.6 or less.

A phosphor containing a first oxide having a specific composition and exhibiting a specific X-ray diffraction pattern emits green light and can exhibit high emission intensity. In addition, the half-value width is relatively narrow, and by applying it to a light-emitting device for a backlight of a display device, the range of color reproducibility of the display device can be further widened.

The emission peak wavelength of the phosphor may be, for example, in the range of 525 nm or more and 535 nm or less, preferably 526 nm or more, or 527 nm or more. The upper limit of the emission peak wavelength of the oxide phosphor may be preferably 533 nm or less, or 531 nm or less. The half width of the emission spectrum of the phosphor may be, for example, 50 nm or less, preferably 45 nm or less, or 42 nm or less. The lower limit of the half-value width may be, for example, 30 nm or more, preferably 35 nm or more, or 38 nm or more.

The composition of the first oxide constituting the phosphor may preferably have a molar ratio of Rb to Si of 0.5 or more and less than 0.8, or more than 0.7 and less than 0.8. The molar ratio of Na to Si may be greater than 0.1 and less than 0.3. The molar ratio of Li to Si may be greater than 2.9 and less than 3.2. The molar ratio of Eu to Si may be greater than 0 and less than 0.3. The molar ratio of the total content of Na and Li to Rb may be 3.75 or more and 6 or less.

The phosphor may have a composition represented by formula (I) below.
_{RbpNaqLirSiOs : Eut ( I} )

In formula (I), p, q, r, s and t are 0.5≦p<1, 0<q<0.5, 2<r<3.5, 3.25<s<4.5 , 0<t<0.3, and 3≦(q+r)/p≦7, preferably 0.5≦p<0.8 or 0.7<p<0.8, 0.1< satisfying q<0.3, 2.9<r<3.2, 3.85<s<4.15, 0<t<0.3, and 3.75≤(q+r)/p≤6 good.

Although the number of moles of Si is 1 in the composition represented by formula (I), the composition of the phosphor may be represented by formula (Ia) below.
Rb _p1 Na _q1 Li _r1 (Li ₃ SiO ₄ ) _s1 O _u1 :Eu _t1 (Ia)

In formula (Ia), p1, q1, r1, s1, u1 and t1 are 1≤p1<2, 0<q1<1, 0<r1<1, 0<u1<1, 0 when s1=2. <t1<0.6 and 0≤(q1+r1)/p1≤1 may be satisfied.

In the X-ray diffraction pattern using CuKα rays, the phosphor has a first diffraction peak in the range of 15.5° or more and 16.5° or less and a Bragg angle of 11.0° or more and 12.0° It has a second diffraction peak within the following range. In the phosphor, the intensity ratio of the second diffraction peak to the first diffraction peak (hereinafter sometimes referred to as "intensity ratio α") may be in the range of 0.6 or more and 1.6 or less, and the emission intensity from the viewpoint of, it may be preferably in the range of 0.6 or more and 1.5 or less, or 0.6 or more and 1.4 or less.

The first diffraction peaks are believed to originate from diffraction from (-2,0,1) and (2,0,1), for example. Also, the second diffraction peak is believed to originate from diffraction from (2,0,0) and (0,0,1), for example. For example, in RbLi(Li ₃ SiO ₄ ) ₂ :Eu (hereinafter sometimes abbreviated as “RbLi”), the first diffraction peak is derived from a lattice plane composed of Rb and Li, and RbNa (Li ₃ In SiO ₄ ) ₂ :Eu (hereinafter sometimes abbreviated as “RbNa”), it originates from a lattice plane composed of Rb and Na. Therefore, the intensity of the first diffraction peak is relatively higher for “RbNa”. (2,0,0) and (0,0,1) are lattice planes composed of Li in "RbLi" and lattice planes composed of Na in "RbNa". On the other hand, the lattice planes (4,0,0) and (0,0,2) shifted by 1/2 of the interplanar spacing are composed of Rb. Therefore, since the intensity of the second diffraction peak depends on the difference in atomic scattering factors between Rb and Li in "RbLi" and between Rb and Na in "RbNa", it is relatively stronger in "RbLi". Then, assuming that the phosphor according to the first aspect has a composition of Rb ₂ NaLi(Li ₃ SiO ₄ ) ₄ :Eu, the intensity ratio is intermediate between “RbLi” and “RbNa”. It is considered to be.

Further, for example, it is known that the lattice volume increases when the host crystal of RbLi(Li ₃ SiO ₄ ) ₂ is activated with Eu, and the lattice volume decreases when the host crystal of RbNa(Li ₃ SiO ₄ ) ₂ is activated with Eu. ing. Here, when activating the host crystal of Rb ₂ NaLi(Li ₃ SiO ₄ ) ₄ with Eu, two patterns are conceivable: a pattern in which Eu replaces Na and a pattern in which Li replaces Li. Therefore, in Rb ₂ NaLi(Li ₃ SiO ₄ ) ₄ , it is considered that the change in lattice size due to Eu substitution is offset. It is believed that such a size compensation effect improves the properties of the phosphor.

The volume average particle diameter of the phosphor may be, for example, 1 μm or more and 500 μm or less, preferably 5 μm or more and 100 μm or less, or 10 μm or more and 40 μm or less. The volume average particle diameter of the phosphor is calculated as the particle diameter corresponding to the cumulative frequency of 50% from the small diameter side in the volume-based particle size distribution. The volume-based particle size distribution is measured by a laser diffraction particle size distribution analyzer. The particle size distribution of the phosphor may be single-peaked.

The phosphor may contain a first oxide and an inorganic substance adhering to the particle surfaces of the first oxide. Attaching an inorganic substance to the surface tends to improve the moisture resistance of the phosphor. Examples of inorganic substances include second oxides different from the first oxides, metal salts, halides, nitrides, and the like, and may include at least one selected from the group consisting of these. , preferably at least one selected from the group consisting of secondary oxides and metal salts. The inorganic substances adhering to the first oxide may be of one type alone or in combination of two or more types. When two or more kinds of inorganic substances are used in combination, a mixture of inorganic substances may be attached to the first oxide, or each inorganic substance may be sequentially attached to form a multilayer structure.

The second oxide may contain at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn. That is, the second oxide is silicon oxide (e.g., SiOx, where x may be 1 or more and 2 or less, preferably _1.5 or more and 2 or less, or about 2), aluminum oxide (e.g., _Al2O3 ). , titanium oxide (e.g. TiO ₂ ), zirconium oxide (e.g. ZrO ₂ ), tin oxide (e.g. SnO, SnO ₂ etc.) and zinc oxide (e.g. ZnO). and may contain at least silicon oxide. The second oxide may consist of only one kind, or may contain two or more kinds.

The content of the second oxide in the phosphor may be 0.02% by mass or more and 30% by mass or less, preferably 1% by mass or more and 15% by mass or less with respect to the phosphor. The content of the second oxide in the phosphor can be measured, for example, by inductively coupled plasma (ICP) emission spectroscopy.

The metal salt may contain, for example, rare earth phosphates, alkaline earth metal phosphates, etc., and may contain at least one selected from the group consisting of these. The rare earth phosphate may contain at least one rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), dysprosium (Dy) and gadolinium (Gd), and preferably contains at least lanthanum. can be

The content of the metal salt in the phosphor may be, for example, 0.1% by mass or more and 20% by mass or less, preferably 0.2% by mass or more and 10% by mass or less, as the content of the metal element.

The inorganic substance adhering to the particle surface of the first oxide may be adhered as inorganic substance particles to cover the surface of the first oxide. Further, the inorganic substance may cover the particle surfaces of the first oxide in the form of a film, or may be arranged on the surface of the first oxide as an inorganic substance layer.

Light-Emitting Device A light-emitting device includes a fluorescent member containing a first phosphor having an emission peak wavelength in the range of 525 nm or more and 535 nm or less, and a light emitting element having an emission peak wavelength in the wavelength range of 380 nm or more and 470 nm or less. The first phosphor contained in the fluorescent member includes at least the phosphor according to the first aspect described above. A light-emitting device having a high luminous flux can be configured by providing a fluorescent member containing a specific phosphor.

An example of a light-emitting device will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a light emitting device according to this embodiment. This light emitting device is an example of a surface mount type light emitting device. The light-emitting device 100 includes a light-emitting element 10 that emits light having an emission peak wavelength on the short wavelength side of visible light (for example, within the range of 380 nm to 470 nm), and a molded body 40 on which the light-emitting element 10 is mounted. The molded body 40 has the first lead 20 and the second lead 30, and is integrally molded with thermoplastic resin or thermosetting resin. A recess having a bottom surface and a side surface is formed in the molded body 40, and the light emitting element 10 is mounted on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30 via wires 60 . The light emitting element 10 is sealed with a fluorescent member 50 . The fluorescent member 50 contains a phosphor 70 that converts the wavelength of light from the light emitting element 10 . The phosphor 70 may contain at least the first phosphor containing the phosphor of the first aspect, and has an emission peak wavelength in a wavelength range different from that of the phosphor of the first aspect by the excitation light from the light emitting element 10. It may further contain a second phosphor, a third phosphor, other light-emitting materials, and the like that emit light.

The fluorescent member may contain a resin and a fluorescent substance. Examples of the resin constituting the fluorescent member include silicone resin and epoxy resin. The fluorescent member may further contain a light diffusing material in addition to the resin and fluorescent material. By containing the light diffusing material, the directivity from the light emitting element can be relaxed and the viewing angle can be increased. Examples of light diffusing materials include silicon oxide, titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide.

The light emitting element emits light having an emission peak wavelength in a wavelength range of 380 nm or more and 470 nm or less, which is a short wavelength region of visible light. The light emitting element may be an excitation light source capable of exciting the oxide phosphor. The light-emitting element preferably has an emission peak wavelength in the range of 380 nm or more and 460 nm or less, more preferably 410 nm or more and 460 nm or less, and more preferably 430 nm or more and 460 nm or less. It is further preferred to have A semiconductor light-emitting element is preferably used as the light-emitting element as the excitation light source. By using a semiconductor light-emitting element as an excitation light source, a light-emitting device with high luminous efficiency and high output linearity with respect to input can be obtained. As the semiconductor light emitting device, for example, a semiconductor light emitting device using a nitride semiconductor can be used. The half width of the emission peak in the emission spectrum of the light emitting element is preferably, for example, 30 nm or less.

A light-emitting device comprises a first phosphor containing the phosphor of the first aspect. The details of the phosphor of the first aspect contained in the light emitting device are as described above. The first phosphor is contained in, for example, a fluorescent member that covers the excitation light source. In a light-emitting device in which the excitation light source is covered with a fluorescent member containing the first phosphor, part of the light emitted from the excitation light source is absorbed by the first phosphor and emitted as green light. By using an excitation light source that emits light having an emission peak wavelength in the range of 380 nm or more and 470 nm or less, the radiated light can be used more effectively, and the loss of light emitted from the light emitting device can be reduced. Thus, a light-emitting device with high luminous efficiency can be provided.

The light-emitting device may further include a second phosphor containing a phosphor other than the phosphor of the first aspect, in addition to the first phosphor. The second phosphor should absorb light from the light source and have an emission peak wavelength in the wavelength range of 500 nm or more and less than 600 nm. The second phosphor can be contained in the fluorescent member in the same manner as the first phosphor.

The second phosphor may have an emission peak wavelength in a wavelength range of 500 nm or more and less than 600 nm, and is preferably a β-sialon phosphor, a halosilicate phosphor, a silicate phosphor, a rare earth aluminate phosphor, and a nitride phosphor. It may be at least one selected from the group consisting of bodies. The β-sialon phosphor may have, for example, a composition represented by formula (IIa) below. The halosilicate phosphor may have, for example, a composition represented by formula (IIb) below. The silicate phosphor may have, for example, a composition represented by formula (IIc) below. The rare earth aluminate phosphor may have, for example, a composition represented by the following formula (IId). The nitride phosphor may have, for example, a composition represented by the following formula (IIe).

Si6 _{- tAltOtN8 -t} :Eu ₍ IIa)
(In the formula, t is a number that satisfies 0<t≦4.2.)
_{(Ca,Sr,Ba)8MgSi4O16 ( F} ,Cl,Br) ₂ :Eu (IIb)
(Ba, Sr, Ca, Mg) ₂ SiO ₄ :Eu (IIc)
(Y, Lu, Gd, Tb) ₃ (Al, Ga) ₅ O ₁₂ :Ce (IId)
(La, Y, Gd) ₃ Si ₆ N ₁₁ :Ce (IIe)

The light-emitting device includes, in addition to the first phosphor, a light-emitting material having an emission peak wavelength in a wavelength range of 500 nm or more and less than 600 nm, for example, a perovskite-based light-emitting material having a composition represented by the following formula (IIf): It may contain a chalcopyrite-based luminescent material having a composition represented by (IIg). A light-emitting material having an emission peak wavelength in the wavelength range of 500 nm or more and less than 600 nm can be contained in the fluorescent member in the same manner as the first phosphor.

(Cs, FA, MA)Pb(F, Cl, Br, I) ₃ (IIf)
(In the formula, FA is formamidinium and MA is methylammonium.)
Ag(Ga,In) _S2 (IIg)

The light-emitting device may further include a third phosphor having an emission peak wavelength in the wavelength range of 600 nm or more and 700 nm or less, in addition to the first phosphor. The third phosphor absorbs light from the light source and emits red light, for example. The third phosphor can be contained in the fluorescent member in the same manner as the first phosphor. The third phosphor may preferably be at least one selected from the group consisting of nitride phosphors and fluoride phosphors. The nitride phosphor may have, for example, a composition represented by formula (IIIa) or (IIIb) below. Fluoride phosphors will be described later.

(Sr,Ca) _{LiAl3N4 :} Eu(IIIa)
(Ca,Sr) _AlSiN3 :Eu(IIIb)

The light-emitting device includes, in addition to the first phosphor, a light-emitting material having an emission peak wavelength in the wavelength range of 600 nm or more and 700 nm or less, for example, a chalcopyrite-based light-emitting material having a composition represented by the following formula (IIIc). A phosphorous compound-based luminescent material having a composition represented by formula (IIId) may be included. A light-emitting material having an emission peak wavelength in the wavelength range of 600 nm or more and 700 nm or less can be contained in the fluorescent member in the same manner as the first phosphor.

(Cu,Ag) _InS2 (IIIc)
(In, Ga, Al) P (IIId)

The third phosphor may more preferably be a fluoride phosphor. The fluoride phosphor has a composition containing an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F. may have. In the composition of the fluoride phosphor, when the number of moles of the alkali metal is 2, the number of moles of Mn may be more than 0 and less than 0.2, preferably 0.01 or more and 0.12 or less. you can Further, in the composition of the fluoride phosphor, when the number of moles of the alkali metal is 2, the number of moles of the element M may be more than 0.8 and less than 1, preferably 0.88 or more and 0.99 or less. can be When the number of moles of alkali metal is 2, the composition of the fluoride particles may be such that the number of moles of F is more than 5 and less than 7, preferably 5.9 or more and 6.1 or less. The composition of fluoride phosphors can be measured, for example, by inductively coupled plasma (ICP) emission spectroscopy.

Element M in the composition of the fluoride phosphor includes at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements. Examples of Group 4 elements include titanium (Ti), zirconium (Zr), hafnium (Hf), and the like, and may contain at least one selected from the group consisting of these. Examples of Group 13 elements include boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl) and the like, including at least one selected from the group consisting of these you can stay Group 14 elements include carbon (C), silicon (Si), germanium (Ge), tin (Sn), etc., and may contain at least one selected from the group consisting of these. The element M may contain at least one Group 14 element, and preferably at least one of Si and Ge. The element M may contain at least one group 13 element and at least one group 14 element, and preferably contains at least Al and at least one of Si and Ge.

The alkali metal in the composition of the fluoride phosphor may contain at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs). . The alkali metal contains at least potassium (K) and may contain at least one selected from the group consisting of lithium (Li), sodium (Na), rubidium (Rb) and cesium (Cs). The ratio of the number of moles of K to the total number of moles of alkali metals in the composition may be, for example, 0.90 or more, preferably 0.97 or more. The upper limit of the molar ratio of K may be, for example, 1 or 0.995 or less. In the composition of the fluoride particles, part of the alkali metals may be replaced with ammonium ions (NH ₄ ⁺ ). When part of the alkali metal is replaced with ammonium ion, the ratio of the number of moles of ammonium ion to the total number of moles of alkali metal in the composition may be, for example, 0.10 or less, preferably 0.03 or less. . The lower limit of the ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

The first composition, which is one aspect of the composition of the fluoride phosphor, may contain at least one selected from the group consisting of Group 4 elements and Group 14 elements as element M, preferably Group 14 elements It may contain at least one selected from the group consisting of, more preferably at least one of Si and Ge, still more preferably at least Si. In addition, in the first composition of the fluoride phosphor, the total number of moles of Si, Ge, and Mn may be 0.9 or more and 1.1 or less, preferably 0.97, with respect to the number of moles of the alkali metal of 2. It may be greater than or equal to 1.03 or less.

The first composition of the fluoride phosphor may be a composition represented by the following formula (IIIe).
A ¹ _b [M ¹ _1-a Mn _a F _c ] (IIIe)

In formula (IIIe), ^A1 may contain at least one selected from the group consisting of Li, Na, K, Rb and Cs. ^M1 contains at least one of Si and Ge, and may further contain at least one element selected from the group consisting of Group 4 elements and Group 14 elements. Mn may be a tetravalent manganese ion. a satisfies 0<a<0.2, b is the absolute value of the charge of the [M ¹ _1−a Mn _a F _c ] ion, and c satisfies 5<c<7.

A ¹ in formula (IIIe) may further include at least one selected from the group consisting of Li, Na, K, Rb and Cs. Also, A ¹ may be partially substituted with an ammonium ion (NH ₄ ⁺ ). When part of A ¹ is replaced with ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of A ¹ in the composition may be, for example, 0.10 or less, preferably 0.05 or less, or 0.03 or less. The lower limit of the ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

a in formula (IIIe) is preferably 0.005 or more and 0.15 or less, or 0.015 or more and 0.1 or less. b may be, for example, 1.8 or more and 2.2 or less, preferably 1.95 or more and 2.05 or less. c may preferably be 5.5 or more and 6.5 or less, or 5.9 or more and 6.1 or less.

The second composition, which is one aspect of the composition of the fluoride phosphor, contains at least one selected from the group consisting of Group 4 elements and Group 14 elements as the element M, and at least one Group 13 element. preferably at least one selected from the group consisting of Group 14 elements and at least one Group 13 element, more preferably at least Si and Al . In addition, in the second composition of the fluoride phosphor, the total number of moles of Si, Al and Mn may be 0.9 or more and 1.1 or less, preferably 0.9 or less, with respect to the number of moles of 2 of the alkali metal. It may be 97 or more and 1.03 or less. Furthermore, in the second composition of the fluoride phosphor, the number of moles of Al may be more than 0 and 0.1 or less, preferably 0.003 or more and 0.015 or less, with respect to the number of moles of 2 of the alkali metal. It's okay.

The second composition of the fluoride phosphor may be a composition represented by the following formula (IIIf).
A ² _g [M ² _1-e Mn _e F _h ] (IIIf)

In formula (IIIf), ^A2 may contain at least one selected from the group consisting of Li, Na, K, Rb and Cs. ^M2 contains at least Si and Al, and may further contain at least one element selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements. Mn may be a tetravalent manganese ion. e satisfies 0<e<0.2, g is the absolute value of the charge of the [M ² _1−e Mn _e F _h ] ion, and h satisfies 5<h<7.

A ² in formula (IIIf) may be partially substituted with an ammonium ion (NH ₄ ⁺ ). When part of ^A2 is replaced with ammonium ions, the ratio of the number of moles of ammonium ions to the total number of moles of ^A2 in the composition may be, for example, 0.10 or less, preferably 0.03 or less. . The lower limit of the ratio of the number of moles of ammonium ions may be, for example, greater than 0, preferably 0.005 or more.

e in formula (IIIf) is preferably 0.005 or more and 0.15 or less, or 0.015 or more and 0.1 or less. g may be, for example, 1.8 or more and 2.2 or less, preferably 1.95 or more and 2.05 or less. h may preferably be 5.5 or more and 6.5 or less, or 5.9 or more and 6.1 or less.

Phosphor production method The phosphor production method includes a preparation step of preparing a raw material mixture containing an Rb source, a Na source, a Li source, an Eu source and a Si source, and a temperature range of 400 ° C. or higher and 800 ° C. or lower. and a heat treatment step of heat treating at a temperature contained therein. The raw material mixture has a molar ratio of Rb to Si of 0.5 or more and less than 1, a molar ratio of Na to Si of greater than 0 and less than 0.5, and a molar ratio of Li to Si of greater than 2 and 3.5. The molar ratio of Eu to Si may be greater than 0 and less than 0.3, and the molar ratio of the total content of Na and Li to Rb may be 3 or more and 7 or less. At least one of the Rb source, Na source, Li source, Eu source and Si source that constitute the raw material mixture may contain an oxide.

By heat-treating a raw material mixture having a predetermined composition at a predetermined temperature, a phosphor having a desired composition and high emission intensity can be efficiently produced. Further, the manufactured phosphor contains a first oxide containing Rb, Na, Li, Eu and Si in its composition, and the first oxide has a molar ratio of Rb to Si of 0.5 or more and less than 1. , the molar ratio of Na to Si is greater than 0 and less than 0.5, the molar ratio of Li to Si is greater than 2 and less than 3.5, and the molar ratio of the total content of Na and Li to Rb is 3 or more It may have a composition that is 7 or less.

In the preparation step, a raw material mixture containing an Rb source, a Na source, a Li source, an Eu source and a Si source is prepared. This raw material mixture is prepared by weighing the Rb source, Na source, Li source, Eu source and Si source so as to obtain a desired blending ratio, and then using a mixing method such as a ball mill or a mixing machine such as a Henschel mixer or V-type blender. It can be obtained by mixing using a mixing method using a mortar and pestle, or the like. Mixing can be performed by dry mixing, or by adding a solvent or the like and performing wet mixing.

The Rb source that constitutes the raw material mixture may be a compound containing Rb, a single substance of Rb, an alloy containing Rb, or the like, and may be at least one selected from the group consisting of these. Examples of compounds containing Rb include carbonates, oxides, halides (fluorides, chlorides, etc.) and the like, and may contain at least one selected from the group consisting of these. As the compound containing Rb, rubidium carbonate, rubidium oxide, and the like can be preferably mentioned. One type of Rb source may be used alone, or two or more types may be used in combination.

The Na source constituting the raw material mixture may be a compound containing Na, elemental Na, an alloy containing Na, or the like, and may be at least one selected from the group consisting of these. Compounds containing Na include carbonates, oxides, halides (fluorides, chlorides, etc.) and the like, and may contain at least one selected from the group consisting of these. As the compound containing Na, preferably sodium carbonate, sodium oxide, and the like can be mentioned. Na source may be used individually by 1 type, and may use 2 or more types together.

The Li source constituting the raw material mixture may be a compound containing Li, elemental Li, an alloy containing Li, or the like, and may be at least one selected from the group consisting of these. Compounds containing Li include carbonates, oxides, halides (fluorides, chlorides, etc.) and the like, and may contain at least one selected from the group consisting of these. Lithium carbonate, lithium oxide, and the like can be preferably used as the compound containing Li. The Li source may be used singly or in combination of two or more.

The Eu source constituting the raw material mixture may be a compound containing Eu, elemental Eu, an alloy containing Eu, or the like, and may be at least one selected from the group consisting of these. Compounds containing Eu include oxides, halides (fluorides, chlorides, etc.) and the like, and may contain at least one selected from the group consisting of these. As a compound containing Eu, europium oxide and the like can be preferably mentioned. The Eu source may be used singly or in combination of two or more.

The Si source constituting the raw material mixture may be a compound containing Si, elemental Si, an alloy containing Si, or the like, and may be at least one selected from the group consisting of these. Compounds containing Si include oxides and the like, and may contain at least one selected from the group consisting of these. As a compound containing Si, silicon oxide or the like can be preferably mentioned. One type of Si source may be used alone, or two or more types may be used in combination.

The composition of the raw material mixture prepared in the preparation step may preferably have a molar ratio of Rb to Si of greater than 0.7 and less than 0.8, and a molar ratio of Na to Si of greater than 0.1 to 0.3. the molar ratio of Li to Si may be greater than 2.9 and less than 3.2; the molar ratio of Eu to Si may be greater than 0 and less than 0.3; The molar ratio of the total content to Rb may be 4 or more and 5 or less.

At least one of the Rb source, Na source, Li source, Eu source and Si source that constitute the raw material mixture contains an oxide. An oxide may be included in at least one of the Eu source and the Si source.

In the heat treatment step, the prepared raw material mixture is heat-treated at a predetermined temperature to obtain a heat-treated product. The heat-treated product obtained in the heat treatment step may contain the target phosphor. The heat treatment temperature in the heat treatment step may be, for example, 400° C. or higher and 800° C. or lower.

The heat treatment step may include raising the temperature to a predetermined heat treatment temperature, maintaining the heat treatment temperature, and lowering the temperature from the heat treatment temperature. The heating rate to the heat treatment temperature may be, for example, 0.1° C./min or more and 20° C./min or less, preferably 0.5° C./min or more, or 1° C./min, as a temperature rising rate from room temperature. or more, and preferably 15° C./min or less, or 10° C./min or less. The heat treatment time for which the heat treatment temperature is maintained may be, for example, 1 hour or more and 100 hours or less, preferably 50 hours or less, or 20 hours or less. The temperature drop rate from the heat treatment temperature may be, for example, 1° C./min or more and 600° C./min or less as the temperature drop rate to room temperature.

The heat treatment step may be performed in one step at a single heat treatment temperature, or may be performed in multiple steps at two or more same or different heat treatment temperatures. When heat treatment is performed multiple times, each heat treatment may be performed continuously, or after the heat treatment, the temperature is once lowered, and if necessary, the next heat treatment may be performed after performing treatments such as pulverization and mixing. . The heat treatment is preferably performed in multiple stages at two or more different heat treatment temperatures from the viewpoint of the emission intensity of the phosphor. Further heat treatment is more preferable. Here, "continuously heat-treated" means that after the preceding heat treatment, the heat treatment temperature of the preceding heat treatment is changed to the next heat treatment temperature without lowering the temperature (for example, 350 ° C. or more as a temperature difference), pulverizing, mixing, etc. , and the heat treatment is performed while maintaining the temperature of the next heat treatment.

When the heat treatment is performed in multiple steps, the heat treatment step includes, for example, a first heat treatment step of obtaining a first heat-treated product by first heat-treating the raw material mixture at a first temperature within the range of 400 ° C. or more and less than 600 ° C.; A second heat treatment step of subjecting the first heat-treated product to a second heat treatment at a second temperature within the range of 600 ° C or higher and 800 ° C or lower, followed by pulverizing and mixing to obtain a second heat-treated product, and a second heat-treated product of 600 ° C or higher. and a third heat treatment step of obtaining a third heat-treated product by performing a third heat treatment at a third temperature within the range of 800° C. or lower. That is, the heat-treated product obtained in the heat treatment step in the phosphor manufacturing method may be the third heat-treated product.

In the first heat treatment step, the raw material mixture is heated, for example, from room temperature to a predetermined first temperature, and held at the first temperature for a predetermined time to obtain a first heat-treated product. The first temperature may preferably be 450° C. or higher, or 500° C. or higher, and preferably 580° C. or lower. The time for which the first temperature is maintained may be, for example, 1 hour or more and 10 hours or less, preferably 2 hours or more and 5 hours or less.

In the second heat treatment step, the temperature of the first heat-treated product is raised, for example, from the first temperature to a predetermined second temperature, and the second temperature is maintained for a predetermined time. That is, the second heat treatment process may be performed continuously with the first heat treatment process. The second temperature may preferably be 650° C. or higher, or 700° C. or higher, and preferably less than 800° C., or 780° C. or lower. The time for which the second temperature is maintained may be, for example, 1 hour or more and 50 hours or less, preferably 2 hours or more and 20 hours or less. After holding the second temperature, the temperature may be lowered, for example, to room temperature or lower. The intermediate heat-treated product obtained after holding the second temperature may be subjected to pulverization treatment. For pulverization, for example, a method using a ball mill or a method using a mortar and pestle can be used. A second heat-treated product is thus obtained. By pulverizing the intermediate heat-treated product to obtain the second heat-treated product, there is a tendency that the emission intensity of the finally obtained phosphor is further improved. The pulverization treatment in the second heat treatment step may be performed at a temperature of, for example, room temperature (eg, 25° C.) or higher and 100° C. or lower, preferably 50° C. or lower.

In the third heat treatment step, the temperature of the second heat-treated product is raised, for example, from room temperature to a predetermined third temperature, and the third temperature is maintained for a predetermined time to obtain the third heat-treated product. The third temperature may preferably be 650° C. or higher, or 700° C. or higher, and preferably be lower than 800° C., or 780° C. or lower. The time for which the third temperature is maintained may be, for example, 1 hour or more and 50 hours or less, preferably 2 hours or more and 20 hours or less.

The heat treatment step in the phosphor manufacturing method further includes at least one step of a fourth heat treatment step of obtaining a fourth heat treatment product by subjecting the third heat treatment product to a fourth heat treatment at a fourth temperature after the third heat treatment step. good too. That is, the heat-treated product obtained in the heat treatment step in the phosphor manufacturing method may be the fourth heat-treated product. Including the fourth heat treatment step in the method for producing the phosphor may increase the emission intensity of the resulting phosphor.

In the fourth heat treatment step, the temperature of the third heat-treated product is raised, for example, from room temperature to a predetermined fourth temperature, and the fourth temperature is maintained for a predetermined time to obtain the fourth heat-treated product. The fourth temperature may be, for example, within the range of 600° C. or higher and 800° C. or lower. The fourth temperature may be preferably 650° C. or higher, or 700° C. or higher, and preferably less than 800° C., or 780° C. or lower. The time for which the fourth temperature is maintained may be, for example, 1 hour or more and 50 hours or less, preferably 2 hours or more and 20 hours or less.

The atmosphere in the heat treatment step may be, for example, a reducing atmosphere. In the reducing atmosphere, for example, the content of hydrogen gas may be 1% by volume or more and 30% by volume or less, preferably 3% by volume or more, or 5% by volume or more, and preferably 20% by volume or less, Alternatively, it may be 15% by volume or less. The heat treatment atmosphere may be a nitrogen-containing atmosphere. The nitrogen-containing atmosphere may have a nitrogen content of, for example, 70% by volume or more, preferably 80% by volume or 85% by volume or more.

The heat treatment of the raw material mixture can be performed using, for example, a tubular furnace. The heat treatment of the raw material mixture can be performed, for example, by filling the mixture in a crucible, boat, or the like made of aluminum oxide. Carbon materials such as graphite, boron nitride (BN), molybdenum materials, etc. can be used in addition to the aluminum oxide material.

The heat-treated product obtained in the heat treatment step may be subjected to treatments such as pulverization, dispersion, washing, filtration, classification, or at least pulverization and classification. The pulverization treatment can be carried out under dry conditions using, for example, a method using a ball mill or a method using a mortar and pestle, or can be carried out under wet conditions by adding a solvent or the like. Classification can be performed using dry sieving or wet sieving. When the classification treatment is performed by a wet sieve, the heat-treated product or the heat-treated product after pulverization is dispersed in a liquid medium to obtain a slurry, and then classified using a wet sieve to obtain a phosphor having a desired particle size. be able to. Examples of the liquid medium include alcohol solvents such as ethanol and isopropyl alcohol, ester solvents such as ethyl acetate, hydrocarbon solvents such as hexane and toluene, halogenated hydrocarbon solvents such as chloroform and dichloroethane, and ethers such as diethyl ether and diisopropyl ether. Organic solvents such as solvents can be mentioned, and mixtures thereof can also be used.

The method for producing a phosphor may include a surface treatment step of adhering an inorganic substance to the particle surfaces of the first oxide. Examples of inorganic substances include second oxides different from the first oxides, metal salts, halides, nitrides, and the like, and may include at least one selected from the group consisting of these. , preferably at least one selected from the group consisting of secondary oxides and metal salts. The surface treatment process can be appropriately selected from known methods depending on the inorganic substance to be adhered.

For example, when the inorganic substance to be adhered in the surface treatment step is a second oxide, for example, by contacting the particles of the first oxide and the metal alkoxide in a liquid medium, at least part of the surface of the particles of the first oxide can be deposited with a second oxide derived from a metal alkoxide. The metal alkoxide may be, for example, a metal alkoxide containing at least one selected from the group consisting of Si, Al, Ti, Zr, Sn and Zn, and a metal alkoxide containing at least one of Si and Al, good. The aliphatic group of the alkoxide that constitutes the metal alkoxide may have, for example, 1 or more and 6 or less carbon atoms. For the details of the method of attaching the second oxide to the particle surface of the first oxide, reference can be made to, for example, the known technique related to the so-called sol-gel method.

The metal alkoxide is preferably at least one selected from the group consisting of tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, trimethoxyaluminum, triethoxyaluminum and triisopropoxyaluminum.

The amount of metal alkoxide added in the surface treatment step may be, for example, 1% by mass or more and 110% by mass or less with respect to the total mass of the first oxide.

Examples of the liquid medium include water; alcohol solvents such as methanol, ethanol and isopropyl alcohol; nitrile solvents such as acetonitrile; and hydrocarbon solvents such as hexane. The liquid medium may contain at least water and an alcoholic solvent. When the liquid medium contains an alcohol-based solvent, the content of the alcohol-based solvent in the liquid medium may be, for example, 60% by mass or more. Also, the content of water in the liquid medium may be, for example, 40% by mass or less, preferably 20% by mass or less.

Moreover, the liquid medium may further contain a pH adjuster. Examples of pH adjusters that can be used include alkaline substances such as ammonia, sodium hydroxide and potassium hydroxide, and acidic substances such as hydrochloric acid, nitric acid, sulfuric acid and acetic acid. When the liquid medium contains a pH adjuster, the pH of the liquid medium may be, for example, 1 or more and 6 or less under acidic conditions. It may be 8 or more and 12 or less under alkaline conditions.

The mass ratio of the liquid medium to the first oxide may be, for example, 100% by mass or more and 1000% by mass or less, preferably 100% by mass or more and 500% by mass or less, more preferably 100% by mass or more and 300% by mass or less. When the mass ratio of the liquid medium is within the above range, there is a tendency that the particle surfaces of the first oxide can be more uniformly covered with the second oxide.

The contact between the first oxide and the metal alkoxide can be performed, for example, by adding the metal alkoxide to the suspension containing the first oxide. At this time, stirring or the like may be performed as necessary. Also, the contact temperature between the first oxide and the metal alkoxide may be, for example, 0° C. or higher and 70° C. or lower. The contact time may be, for example, from 1 hour to 12 hours. The contact time includes the time required for adding the metal alkoxide.

In the surface treatment step, heat treatment may be performed after the inorganic substance is attached to the surface of the particles of the first oxide. The heat treatment may improve the stability of the first oxide to which the inorganic substance is attached. The heat treatment temperature may be, for example, 100° C. or higher and 400° C. or lower. Also, the heat treatment time may be, for example, 1 hour or more and 50 hours or less.

In the surface treatment step, the adhesion of the inorganic substance to the first oxide may be performed multiple times. When the inorganic substance is deposited multiple times, the deposited inorganic substance may be the same or different.

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

(Example 1)
Rb ₂ CO ₃ , Na ₂ CO ₃ , Li ₂ CO ₃ , SiO ₂ and Eu ₂ O ₃ are used as Rb source, Na source, Li source, Si source and Eu source, respectively, and these are charged composition ratio, each element A raw material mixture was obtained by weighing and mixing so that the molar ratio of Rb:Na:Li:Si:Eu=0.75:0.25:3:1:0.04. The raw material mixture is filled in a container made of aluminum oxide material, subjected to a first heat treatment at 550° C. (first temperature) for 2 hours in a nitrogen/hydrogen mixed gas (9/1) atmosphere, and then heated to 750° C. (second temperature ) to perform a second heat treatment for an additional 10 hours. After that, the temperature was lowered and pulverization was performed, and then the third heat treatment was performed at 750° C. (third temperature) for 5 hours. By pulverizing this, powder of phosphor E1 of Example 1 was obtained.

(Example 2)
In Example 1, in the same manner as in Example 1, except that after the third heat treatment and pulverization, the fourth heat treatment was further performed at 750 ° C. (fourth temperature) for 5 hours and pulverization was performed. No. 2 phosphor E2 powder was obtained.

(Example 3)
In Example 1, except that the heat treatment temperature (second temperature) of the second heat treatment and the heat treatment temperature (third temperature) of the third heat treatment were changed to 760 ° C., in the same manner as in Example 1, A powder of phosphor E3 was obtained.

(Example 4)
In Example 2, except that the heat treatment temperature (second temperature) of the second heat treatment, the heat treatment temperature (third temperature) of the third heat treatment, and the heat treatment temperature (fourth temperature) of the fourth heat treatment were changed to 760 ° C. Powder of the phosphor E4 of Example 4 was obtained in the same manner as in Example 2.

(Example 5)
In Example 2, the molar ratio of each element was changed to Rb: Na: Li: Si: Eu = 0.75: 0.125: 3.125: 1: 0.04. A powder of phosphor E5 of Example 5 was obtained in the same manner as in Example 2.

(Example 6)
In Example 4, except that the molar ratio of each element was changed to Rb: Na: Li: Si: Eu = 0.75: 0.125: 3.125: 1: 0.04. A powder of phosphor E6 of Example 6 was obtained in the same manner as in Example 3.

(Reference example)
A β-SiAlON phosphor having an emission peak wavelength of 529 nm was used as phosphor C0 of a reference example.

(Example 0)
A powder of phosphor E0 of Example 0 was obtained in the same manner as in Example 1, except that the third heat treatment at 750° C. was not performed.

(Comparative example 2)
In Example 0, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0:3.5:1:0.04, In the same manner as in Example 0, powder of phosphor C2 of Comparative Example 2 was obtained.

(Comparative Example 3)
In Example 1, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0:3.5:1:0.04, Powder of phosphor C3 of Comparative Example 3 was obtained in the same manner as in Example 1.

(Comparative Example 4)
In Example 2, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0:3.5:1:0.04, Powder of phosphor C4 of Comparative Example 4 was obtained in the same manner as in Example 2.

(Comparative Example 5)
In Example 0, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=1:0:3:1:0.08. Similarly, powder of phosphor C5 of Comparative Example 5 was obtained.

(Comparative Example 6)
In Example 1, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=1:0:3:1:0.08. Similarly, powder of phosphor C6 of Comparative Example 6 was obtained.

(Comparative Example 7)
In Example 2, except that the raw material mixture was changed so that the molar ratio of each element was Rb: Na: Li: Si: Eu = 1: 0: 3: 1: 0.08. Similarly, powder of phosphor C7 of Comparative Example 7 was obtained.

(Comparative Example 8)
In Example 0, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0.5:3:1:0.04, In the same manner as in Example 0, powder of phosphor C8 of Comparative Example 8 was obtained.

(Comparative Example 9)
In Example 1, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0.5:3:1:0.04, Powder of phosphor C9 of Comparative Example 9 was obtained in the same manner as in Example 1.

(Comparative Example 10)
In Example 2, except that the raw material mixture was changed so that the molar ratio of each element was Rb:Na:Li:Si:Eu=0.5:0.5:3:1:0.04, Powder of phosphor C10 of Comparative Example 10 was obtained in the same manner as in Example 2.

(Comparative Example 11)
Rb ₂ CO ₃ , Li ₂ CO ₃ , SiO ₂ and Eu ₂ O ₃ were used as Rb source, Li source, Si source and Eu source, respectively. :Si:Eu=0.5:3.5:1:0.04, and a raw material mixture was obtained by weighing and mixing so that the total amount of the raw material mixture was 20 g. The raw material mixture was filled in a container made of aluminum oxide material, and after heat treatment at 550° C. for 5 hours in a nitrogen/hydrogen mixed gas (9/1) atmosphere, pulverization was performed. After that, reheating was performed at 750° C. for 10 hours. By pulverizing this, powder of phosphor C11 of Comparative Example 11 was obtained.

(Comparative Example 12)
Except that in Comparative Example 11, the molar ratio of each element was set to Rb:Li:Si:Eu=1:3:1:0.02, and the heat treatment was performed in only one step at 1000° C. for 4 hours. A powder of phosphor C12 of Comparative Example 12 was obtained under the same conditions as in Comparative Example 11.

<Evaluation>
(X-ray diffraction spectrum)
For the obtained phosphor, a sample horizontal multi-purpose X-ray diffraction device (product name: Ultima IV, manufactured by Rigaku Co., Ltd., X-ray source: CuKα ray (λ = 1.5418 Å), tube voltage 40 kV, tube current 40 mA). were used to measure X-ray diffraction (XRD) spectra, respectively. In the measured XRD spectrum, a first diffraction peak with a Bragg angle of 15.5 ° or more and 16.5 ° or less and a second diffraction peak with a Bragg angle of 11.0 ° or more and 12.0 ° or less are specified, The intensity ratio (intensity ratio α) of the second diffraction peak to the first diffraction peak was calculated. FIG. 4 shows the XRD spectra of Example 1 and Comparative Examples 3, 7 and 9. FIG. In FIG. 4, the first diffraction peak and the second diffraction peak are shown enclosed by solid lines.

(Luminous properties)
The emission characteristics of the phosphor powder were measured with a quantum efficiency measurement system: QE-2000 (manufactured by Otsuka Electronics Co., Ltd.) with an excitation light wavelength of 450 nm. Relative emission energy (relative ENG: %), emission peak wavelength (λp: nm), and full width at half maximum (fwhm: nm) were obtained from the obtained emission spectrum. Table 1 shows the results. The relative luminescence energy (relative ENG (%)) was obtained based on the luminescence energy of the reference example (β-SiAlON).

Table 1 shows the charge composition ratios and the evaluation results of Examples 0 to 2 and Comparative Examples 2 to 12 for the purpose of comparing characteristics due to differences in production methods. In Comparative Examples 2 and 11, almost no target phase was generated, so the intensity ratio α was not calculated. In addition, Table 2 shows the charge composition ratios of Examples 1 to 6 and Comparative Examples 3, 7 and 9 and the evaluation results for the purpose of comparing properties by changing the composition. Also, FIG. 2 shows the relationship between the intensity ratio α and the relative emission energy (relative ENG). FIG. 3 shows the relationship between the intensity ratio α and the emission peak wavelength (λp).

As shown in Table 1, it can be seen that the luminous energy is increased by the three-step heat treatment for any composition. In addition, some compositions were further improved by the four-step heat treatment. In Comparative Example 2, almost no target phase was generated, and the emission spectrum was different from those of other Examples and Comparative Examples due to the presence of by-products, and it is considered that the half-value width was significantly wider than those of these. In Comparative Example 11, since the second heat treatment was not performed, a phosphor with sufficient characteristics could not be obtained with good reproducibility when the scale of synthesis was increased. In Comparative Example 12, since the first temperature was relatively high, the phosphor melted. For this reason, a strong pulverization process is required to obtain phosphor powder, resulting in poor workability.

As shown in Table 2, the phosphors obtained in Examples 1 to 6 have higher emission energy and narrower half-value widths than those of Reference Example and Comparative Examples 3, 7 and 9. are doing. Also, as shown in FIG. 2, it can be seen that the relative ENG increases when the intensity ratio α is in the range of 0.6≦α≦1.6.

The reason for this is presumed as follows, for example. First, the phosphor has a composition represented by ALi ₃ SiO _{4 (} A is the remaining alkali metal) _. presumed to have In Comparative Example 3, channels occupied by Rb and channels occupied by Li are alternately arranged, and in Comparative Example 9, channels occupied by Rb and channels occupied by Na are arranged alternately (channels occupied by Rb are R channels and channels occupied by Li and Na are referred to as LN channels). And the XRD peaks at 11° to 12° originate from diffraction from the (2,0,0) and (0,0,1) planes, and the peaks at 15.5° to 16.5° are (-2 , 0,1) and (2,0,1) planes. The (2,0,0) and (0,0,1) planes are lattice planes composed of atoms in the LN channel, but are shifted by 1/2 of the interplanar spacing (4,0 ,0) and (0,0,2) are composed of Rb in the R channel. Therefore, since the peak intensity at 11° depends on the difference in atomic scattering factor between Rb and the alkali metal in the LN channel, the intensity is highest in Comparative Example 3 in which Li occupies the LN channel. On the other hand, the (−2,0,1) and (2,0,1) planes are lattice planes that pass through the atoms in both the R and LN channels, so the peak intensity depends on the sum of the atomic scattering factors Therefore, the intensity is the highest in Comparative Example 9 in which Na occupies the LN channel. That is, the intensity ratio α is related to the ratio of Li and Na occupying the LN channel, and it is presumed that Li and Na co-occupy the LN channel in the phosphors shown in the examples.

When the activating element replaces the mother crystal, in Comparative Example 3, the lattice constant of the crystal increases due to the replacement with the Li site, and in Comparative Example 9, the lattice constant decreases due to the replacement with the Na site. Therefore, it is presumed that in the compositions of the examples, the strain that should occur in the mother crystal is offset by the activating element entering the Li site and the case where the activating element enters the Na site, thereby improving the characteristics. In addition, the fact that the excessive addition of Rb can reduce the probability of erroneous substitution of the activating element at the Rb site is also considered to be one of the reasons for the improvement in characteristics.

Also, as shown in FIG. 3, it can be seen that the emission peak wavelength becomes longer as the intensity ratio α increases. This is because, for example, as the content of Li increases, the lattice constant of the matrix becomes smaller, and the effect of crystal field splitting on the activation element becomes greater. It is presumed that this is because the energy difference between

(Example 7)
The powder of phosphor E4 obtained in Example 4 was subjected to ball milling using an organic solvent as a dispersion medium. After that, coarse particles were removed with a sieve with an opening of 41 μm, and then fine particles were removed with a sieve with an opening of 15 μm. By drying this, powder of phosphor E7 of Example 7 subjected to classification treatment was obtained.

(Example 8)
In Example 7, the powder of phosphor E8 of Example 8 was obtained under the same conditions as in Example 7 except that the classification operation after dispersion was changed to the removal of fine particles with a sieve with an opening of 41 μm. rice field.

(Example 9)
In Example 7, the powder of phosphor E9 of Example 9 was obtained under the same conditions as in Example 7 except that the classification operation after dispersion was changed to remove coarse particles with a sieve with an opening of 15 μm. .

<Evaluation>
(Volume average particle size)
The volume average particle diameter (median diameter: Dm) is measured by a laser diffraction particle size distribution analyzer (for example, manufactured by MALVERN, product name: MASTER SIZER 3000). It was calculated as a particle size corresponding to %. Table 3 shows the results.

As shown in Table 3, by using an organic solvent, the deterioration of the properties of the heat-treated product is suppressed, and by performing a classification operation, the particle size is adjusted from small to large according to the application. be able to For example, when comparing only the light emission characteristics, the characteristics of Example 8 are higher. It may not be suitable as a phosphor to be used.

(Example 10)
The phosphor E2 obtained in Example 2 was used as the first phosphor, and the phosphor having the composition represented by K ₂ SiF ₆ :Mn was used as the third phosphor, and the light emitting element had an emission peak wavelength of 450 nm. A light-emitting device was produced by combining the LEDs by a conventional method. At that time, the fluorescent member containing the phosphor and the resin was prepared so that the chromaticity coordinates (x, y) of the emitted light color were x=0.262 and y=0.223.

(Comparative Examples 13 to 15)
Light-emitting devices were produced in the same manner as in Example 10, except that the first phosphor used was changed as shown in Table 4.

<Evaluation>
The chromaticity coordinates and luminous flux of the obtained light-emitting device were measured. The luminous flux of the light emitting device was measured using an integral total luminous flux measuring device. Table 4 also shows the charge ratio of the alkali metals in the production of the phosphor, the chromaticity coordinates, the luminous flux ratio, and the range of color reproducibility of the obtained light-emitting device. The luminous flux ratio was calculated based on Comparative Example 15 using the phosphor of Reference Example. Also, the range of color reproducibility indicates the coverage (%) of the BT2020 standard.

As shown in Table 4, by using phosphor E2, the range of luminous flux and color reproducibility is increased compared to the case of using phosphor C3. The improvement in the luminous flux is thought to be due to an increase in the emission energy of the phosphor used, and the widening of the color reproducibility range is thought to be due to a change in the emission peak wavelength of the phosphor used to a shorter wavelength. Also, the luminous flux is improved as compared with the case of using the phosphor C9. The reason for this is presumed to be that the emission energy of the phosphor used has increased.

(Example 11)
15 g of phosphor E7 produced in Example 7 was weighed and put into a mixed solution of 27 mL of ethanol, 6.2 mL of ammonia water, and 3.3 mL of pure water. While stirring with a stirrer, the liquid temperature was kept at room temperature (25° C.) to obtain a reaction mother liquid. 0.8 g of tetraethoxysilane (TEOS: Si(OC ₂ H ₅ ) ₄ ) was weighed and added dropwise to the stirring reaction mother liquor over about 2 hours. After that, the stirring was continued for 1 hour, and the stirring was terminated. The resulting precipitate was subjected to solid-liquid separation, washed with ethanol, and dried to obtain phosphor E11 of Example 11 to which a film made of silicon dioxide (SiO ₂ ) was attached.

(Example 12)
The phosphor E11 produced in Example 11 was subjected to heat treatment in air at a temperature of 350° C. for 10 hours to obtain phosphor E12 of Example 12.

(Example 13)
15 g of the phosphor E7 produced in Example 7 and 0.8 g of TEOS were weighed and added to 27 mL of ethanol. Then, while maintaining the liquid temperature at 50° C., the mixture was stirred with a stirrer for 3 hours. The precipitate obtained after stirring was subjected to solid-liquid separation, washed with ethanol, and dried to obtain phosphor E13 of Example 13.

(Example 14)
A film composed of silicon dioxide (SiO ₂ ) was further attached to the phosphor E13 produced in Example 13 under the same conditions as in Example 13 to produce phosphor E14 of Example 14. .

In any of Examples 11 to 14, a film composed of silicon dioxide could be adhered to the surface of the phosphor. These films are considered to function as protective films capable of suppressing deterioration of the phosphor due to the external environment.

The phosphor of the present disclosure is particularly used in a light-emitting device that uses a light-emitting diode as an excitation light source. And it can be suitably used for small strobes and the like.

10: Light-emitting element, 20: First lead, 30: Second lead, 40: Molded body, 50: Fluorescent member, 60: Wire, 70: Phosphor, 100: Light-emitting device.

Claims (12)

A first oxide containing Rb, Na, Li, Eu and Si in its composition,
In the first oxide, the molar ratio of Rb to Si is 0.5 or more and less than 1, the molar ratio of Na to Si is greater than 0 and less than 0.5, and the molar ratio of Li to Si is greater than 2. is less than 3.5 and has a composition in which the molar ratio of the total content of Na and Li to Rb is 3 or more and 7 or less,
In the X-ray diffraction pattern using CuKα rays, the first diffraction peak has a Bragg angle of 15.5° or more and 16.5° or less, and the Bragg angle of 11.0° or more and 12.0° or less. and a second diffraction peak at
A phosphor wherein α is in the range of 0.6 or more and 1.6 or less, where α is the intensity ratio of the second diffraction peak to the first diffraction peak. The molar ratio of Rb to Si is 0.5 or more and less than 0.8, the molar ratio of Na to Si is greater than 0.1 and less than 0.3, and the molar ratio of Li to Si is 2.9. A composition in which the molar ratio of Eu to Si is greater than 0 and less than 0.3, and the molar ratio of the total content of Na and Li to Rb is 3.75 or more and 6 or less The phosphor according to claim 1, having 2. The phosphor according to claim 1, having a composition represented by the following formula (I).
_{RbpNaqLirSiOs : Eut ( I} )
(In formula (I), p, q, r, s and t are 0.5≦p<1, 0<q<0.5, 2<r<3.5, 3.25<s<4. 5, 0<t<0.3, and 3≤(q+r)/p≤7.) Said p, q, r, s and t are 0.5≦p<0.8, 0.1<q<0.3, 2.9<r<3.2, 3.85<s<4. 15, 0<t<0.3, and 3.75≦(q+r)/p≦6. A fluorescent member containing a first phosphor that includes the phosphor according to any one of claims 1 to 4 and has an emission peak wavelength in the range of 525 nm or more and 535 nm or less, and emits light in a wavelength range of 380 nm or more and 470 nm or less and a light emitting element having a peak wavelength. 6. The light-emitting device according to claim 5, wherein the fluorescent member further includes a second phosphor or a light-emitting material having an emission peak wavelength in a wavelength range of 500 nm or more and less than 600 nm. 7. The light-emitting device according to claim 5, wherein the fluorescent member further includes a third phosphor or light-emitting material having an emission peak wavelength in a wavelength range of 600 nm or more and 700 nm or less. The third phosphor contains an element M containing at least one selected from the group consisting of Group 4 elements, Group 13 elements and Group 14 elements, an alkali metal, Mn, and F, When the number of moles of the alkali metal is 2, the number of moles of Mn is more than 0 and less than 0.2, the number of moles of the element M is more than 0.8 and less than 1, and the number of moles of F is 8. The light emitting device of claim 7, having a composition that is greater than 5 and less than 7. heat-treating a raw material mixture containing an Rb source, a Na source, a Li source, an Eu source and a Si source at a temperature within the range of 400° C. or higher and 800° C. or lower;
The raw material mixture has a molar ratio of Rb to Si of 0.5 or more and less than 1, a molar ratio of Na to Si of more than 0 and less than 0.5, and a molar ratio of Li to Si of more than 2 to 3. 5, the molar ratio of Eu to Si is greater than 0 and less than 0.3, the molar ratio of the total content of Na and Li to Rb is 3 or more and 7 or less, and the Rb source, Na source, Li A method of making a phosphor, wherein at least one of the source, the Eu source and the Si source comprises an oxide. In the raw material mixture, the molar ratio of Rb to Si is greater than 0.7 and less than 0.8, the molar ratio of Na to Si is greater than 0.1 and less than 0.3, and the molar ratio of Li to Si is greater than 0.1 and less than 0.3. The molar ratio is greater than 2.9 and less than 3.2, the molar ratio of Eu to Si is greater than 0 and less than 0.3, and the molar ratio of the total content of Na and Li to Rb is 4 or more and 5 10. The method for producing a phosphor according to claim 9, comprising: In the heat treatment, the raw material mixture is subjected to a first heat treatment at a first temperature within a range of 400° C. or more and less than 600° C. to obtain a first heat-treated product;
obtaining a second heat-treated product by subjecting the first heat-treated product to a second heat treatment at a second temperature within the range of 600° C. or higher and 800° C. or lower, and then lowering the temperature;
11. The production of the phosphor according to claim 9 or 10, comprising subjecting the second heat-treated product to a third heat treatment at a third temperature within the range of 600° C. or higher and 800° C. or lower to obtain a third heat-treated product. Method. The phosphor obtained by heat-treating the raw material mixture includes a first oxide containing Rb, Na, Li, Eu and Si in its composition, and the first oxide has a molar ratio of Rb to Si of 0. .5 or more and less than 1, the molar ratio of Na to Si is greater than 0 and less than 0.5, the molar ratio of Li to Si is greater than 2 and less than 3.5, and the total content of Na and Li is 12. The method for producing a phosphor according to any one of claims 9 to 11, wherein the composition has a molar ratio to Rb of 3 or more and 7 or less.

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