JP2015129250A - Fluoride phosphor and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a red light-emitting phosphor excellent in durability and a method for producing the same.SOLUTION: The method for producing the fluoride phosphor includes a step in which, in a reaction mixture that contains a fluoride represented by general formula (I) A[MMnF] and a treatment liquid containing at least one cation selected from the group consisting of Li, Na, K, Rb, Cs, and NHand an organic acid anion, the fluoride is brought into contact with the cation and the organic acid anion. In the formula, A represents at least one cation selected from the group consisting of Li, Na, K, Rb, Cs, and NH; M represents at least one element selected from the group consisting of group 4 elements and group 14 elements; and a satisfies 0<a<0.2.

Description

  The present invention relates to a fluoride phosphor and a method for producing the same.

  A light emitting diode (LED) is a semiconductor light emitting device produced from a metal compound such as gallium nitride (GaN). Various light emitting devices that emit light in white, light bulb color, orange color, etc. by combining the semiconductor light emitting element and the phosphor have been developed. These light emitting devices that emit white light and the like are obtained by the principle of light color mixing. As a method for emitting white light, a method using a light emitting element that emits ultraviolet light and three types of phosphors that emit red (R), green (G), and blue (B), and blue light emission. A method using a light emitting element that emits light and a phosphor that emits yellow or the like is well known. A light emitting device using a light emitting element that emits blue light and a phosphor that emits yellow light or the like is required in a wide range of fields such as lighting such as a fluorescent lamp, in-vehicle illumination, a display, and a backlight for liquid crystal. Among these, as a phosphor used for a display application, in order to reproduce a wide range of colors on chromaticity coordinates, it is required to have good color purity as well as luminous efficiency. In particular, a phosphor used for a display is required to have a compatibility with a color filter, and a phosphor having a narrow emission peak half-value width is required.

For example, as a red light emitting phosphor having an excitation band in a blue region and a narrow half-value width of an emission peak, K ₂ AlF ₅ : Mn ⁴⁺ , K ₃ AlF ₆ : Mn ⁴⁺ , K ₃ GaF ₆ : Mn ⁴⁺ , Zn ₂ AlF ₇ : Mn ⁴⁺ , KIn ₂ F ₇ : Mn ⁴⁺ , K ₂ SiF ₆ : Mn ⁴⁺ , K ₂ TiF ₆ : Mn ⁴⁺ , K ₃ ZrF ₇ : Mn ⁴⁺ , Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ , BaTiF ₆ : Mn ⁴⁺ , K ₂ SnF ₆ : Mn ⁴⁺ , Na ₂ TiF ₆ : Mn ⁴⁺ , Na ₂ ZrF ₆ : Mn ⁴⁺ , KRbTiF ₆ : Mn ⁴⁺ , K ₂ Si _0.5 Ge _0.5 A fluoride phosphor having a composition such as F ₆ : Mn ⁴⁺ is known (see, for example, Patent Document 1).

Special table 2009-528429 gazette

There is a demand for practical use of a red-emitting Mn ^{4 +} -activated fluoride phosphor that is suitable for display applications and has a narrow emission peak half-value width, but there is room for improvement in durability in the prior art, It was insufficient for use in harsh environments such as lighting applications.
In view of the above, an object of the present invention is to provide a red-emitting phosphor excellent in durability and a method for producing the same in order to solve the conventional problems.

Specific means for solving the above problems are as follows, and the present invention includes the following aspects.
The first aspect of the present invention is a fluoride represented by the following general formula (I) and at least one selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^+. A method for producing a fluoride phosphor comprising a step of bringing a fluoride into contact with the cation and an organic acid anion in a reaction mixture containing a seed cation and an organic acid anion.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a Group 4 element and Group 14 It represents at least one element selected from the group consisting of elements, and a satisfies 0 <a <0.2.

A second aspect of the present invention is a fluoride phosphor containing a fluoride represented by the following general formula (I) and an organic acid salt.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a Group 4 element and Group 14 It represents at least one element selected from the group consisting of elements, and a satisfies 0 <a <0.2.
A 3rd aspect of this invention is a light-emitting device provided with a fluoride fluorescent substance and the light source which emits the light of the wavelength range of 380 nm-485 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescent substance of the red light emission excellent in durability and its manufacturing method can be provided.

It is a schematic sectional drawing which shows an example of the light-emitting device which concerns on this embodiment. It is a figure which shows an example of the SEM image of the fluoride fluorescent substance which concerns on this embodiment. It is a figure which shows an example of the SEM image of the fluoride fluorescent substance which concerns on a comparative example. It is a figure which shows the durability evaluation result of the fluoride fluorescent substance which concerns on this embodiment.

Hereinafter, the fluoride fluorescent substance, the manufacturing method thereof, and the light emitting device according to the present invention will be described with reference to embodiments and examples. However, the embodiment described below exemplifies a fluoride phosphor, a manufacturing method thereof, and a light-emitting device for embodying the technical idea of the present invention. The manufacturing method and the light emitting device are not specified as follows.
The relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Specifically, 380 nm to 455 nm is blue purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red , 610 nm to 780 nm is red. In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. . Moreover, the numerical range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. Further, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.

<Method for producing fluoride phosphor>
The first aspect of the method for producing a fluoride phosphor according to the present invention includes a fluoride represented by the following general formula (I), Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^+. A step of bringing a fluoride into contact with the cation and the organic acid anion in a reaction mixture containing a treatment liquid containing at least one cation selected from the group consisting of the organic acid anion (hereinafter referred to as “first step”). Is a method for producing a fluoride phosphor.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a Group 4 element and Group 14 It represents at least one element selected from the group consisting of elements, and a satisfies 0 <a <0.2.

Bringing the fluoride represented by the general formula (I) into contact with at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic acid anion. Thus, a fluoride phosphor having excellent durability can be obtained. This may be because, for example, the organic acid salt is formed in at least a part of the surface of the fluoride.

The reason why the durability of the fluoride phosphor is improved by forming an organic acid salt on the surface of the fluoride is not clear, but for example, crystals in the surface region of the fluoride represented by the general formula (I) At least one kind of cation and organic acid anion selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ enter the structure, so that the arrangement of atoms is arranged, and as a result This is because a strong crystal structure is formed.

In the production method of the present invention, a treatment liquid containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ^+, and NH ₄ ⁺ and an organic acid anion is used. There is also an effect of removing excess manganese ions contained in the chemical. Excess manganese ions not only contribute to light emission, but can cause a reduction in durability by reducing some of the tetravalent manganese ions to divalent manganese ions. When removing the excess manganese ions, the treatment liquid contains the cation and the organic acid anion, so that the cation contained in the base material of fluoride such as potassium can be prevented from being dissolved. For example, when potassium cation is included in the treatment liquid and potassium element is contained in the fluoride, the potassium cation concentration in the treatment liquid is increased to bring it closer to an equilibrium state, thereby further dissolving potassium element and the like from the fluoride. Can be effectively prevented.

In addition, since the treatment liquid contains at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic acid anion, an organic acid salt is formed on the surface. Is formed, and the dissolution of the fluoride can be prevented.

  Further, in the step of bringing the fluoride into contact with the treatment liquid, particles having a relatively small particle size contained in the fluoride are removed together with the treatment liquid, so that the particle size distribution changes to a single peak with a narrow distribution width. Tend to. Thereby, it is thought that durability of the obtained fluoride fluorescent substance improves more.

  The fluoride phosphor obtained by the production method of the present invention is excellent in durability. The durability of the fluoride phosphor can be evaluated by, for example, an accelerated test using laser light. The durability of the fluoride phosphor can be evaluated by a method of mounting it on a light emitting device and confirming its lifetime, but in that case, the evaluation takes 1000 to tens of thousands of hours.

The durability evaluation test of the fluoride phosphor using laser light can be performed, for example, according to the following procedure.
A semiconductor laser that generates light having a wavelength of 450 nm is prepared, and temperature adjustment is performed to stabilize the light output. About 0.1 g of fluoride phosphor is set in a cell for measuring powder luminance. The light emitted from the semiconductor laser is applied to the fluoride phosphor in the cell. At this time, the current applied to the semiconductor laser is adjusted so that the light density is 3.5 W / cm ² . A change in powder luminance is measured by taking light from a portion irradiated with laser light into a photomultiplier tube. At this time, in order to remove the influence of the laser beam on the powder luminance, it is preferable to remove the laser beam reflected from the phosphor using an optical filter.

Fluoride The fluoride represented by the general formula (I) used in the method for producing a fluoride phosphor itself functions as a phosphor. The production method of the present invention can improve the durability of the resulting fluoride phosphor without impairing the function of the fluoride phosphor represented by the general formula (I).

  The particle size and particle size distribution of the fluoride represented by the general formula (I) (hereinafter, also simply referred to as “fluoride”) are not particularly limited, but from the viewpoint of emission intensity and durability, the particle size distribution of a single peak is It is preferable to show a single peak particle size distribution with a narrow distribution width. Further, the surface area and bulk density of the fluoride are not particularly limited.

Fluoride is a phosphor activated with Mn ⁴⁺ and can absorb red light in the short wavelength region of visible light and emit red light. The excitation light that is light in the short wavelength region of visible light is preferably mainly light in the blue region. Specifically, the excitation light preferably has a main peak wavelength of the intensity spectrum in the range of 380 nm to 500 nm, more preferably in the range of 380 nm to 485 nm, and in the range of 400 nm to 485 nm. Is more preferable, and it is particularly preferable to exist in the range of 440 nm to 480 nm.

  The emission wavelength of fluoride is not particularly limited as long as it is longer than the excitation light and is red. The emission spectrum of fluoride preferably has a peak wavelength in the range of 610 nm to 650 nm. The half width of the emission spectrum is preferably small, specifically 10 nm or less.

A in the general formula (I) is at least one selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and ammonium (NH ₄ ). Represents a cation. A is selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and ammonium (NH ₄ ), and at least contains Na and / or K A cation composed of one kind of alkali metal element is preferable. A cation composed of at least one alkali metal element containing potassium (K) is preferable.

M in the general formula (I) is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and M is titanium (Ti), zirconium (Zr), It is preferably at least one selected from the group consisting of hafnium (Hf), silicon (Si), germanium (Ge), and tin (Sn), silicon (Si), or silicon (Si) and germanium (Ge) It is more preferable that silicon (Si) or silicon (Si) and germanium (Ge) are included.
When M includes silicon (Si), or silicon (Si) and germanium (Ge), a part of at least one of Si and Ge includes a Group 4 element including Ti, Zr, and Hf, and C and Sn It may be substituted with at least one selected from the group consisting of Group 14 elements.

Treatment liquid The treatment liquid used in the production method of the present invention includes lithium cation (Li ⁺ ), sodium cation (Na ⁺ ), potassium cation (K ⁺ ), rubidium cation (Rb ⁺ ), cesium cation (Cs ⁺ ) and fourth. The solution is not particularly limited as long as it is a solution containing at least one cation selected from the group consisting of a quaternary ammonium cation (NH ₄ ⁺ ) and an organic acid anion. The treatment liquid contains a solvent in addition to the cation and the organic acid anion. Although it does not restrict | limit especially as a solvent, It is preferable that water is included at least.
The treatment liquid may further contain a solvent other than water. Examples of the solvent other than water include organic solvents such as alcohol solvents such as methanol, ethanol and isopropyl alcohol, ketone solvents such as acetone and diisopropyl ether, and ether solvents such as diethyl ether. When the treatment liquid contains an organic solvent other than water, the content is not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected according to the purpose and the like.

The organic acid anion contained in the treatment liquid can be introduced into the treatment liquid by dissolving a compound capable of releasing the organic acid anion in a solvent. The organic acid anion contained in the treatment liquid is an organic acid anion released from at least one organic acid anion-containing compound selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids and salts thereof. preferable. The organic acid anion can be introduced into the treatment liquid by dissolving the organic acid anion-containing compound in a solvent. Among the organic acid anion-containing compounds, the aliphatic carboxylate or the aromatic carboxylate includes an aliphatic carboxylate anion and / or an aromatic carboxylate anion, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs. An organic acid salt to which at least one cation selected from the group consisting of ⁺ and NH ₄ ⁺ is bonded may be mentioned. This organic acid salt can serve as at least one cation source selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic anionic acid source. The organic acid anion may be used alone or in combination of two or more in the treatment liquid.

Examples of the aliphatic carboxylic acid include saturated aliphatic carboxylic acid, unsaturated aliphatic carboxylic acid, and aliphatic hydroxycarboxylic acid. The aliphatic carboxylic acid may be a polyvalent carboxylic acid having a plurality of carboxyl groups. Among the polyvalent carboxylic acids, dicarboxylic acids or tricarboxylic acids having 2 or 3 carboxyl groups in one molecule are preferable.
Examples of the saturated aliphatic carboxylic acid include carboxylic acids having a linear or branched hydrocarbon group having 1 to 18 carbon atoms. Specifically, saturated aliphatic carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margarine An acid, a stearic acid, etc. can be mentioned.
Examples of the unsaturated aliphatic carboxylic acid include methacrylic acid.
Examples of the saturated aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, and suberic acid.
Examples of the unsaturated aliphatic dicarboxylic acid include maleic acid and fumaric acid.
Examples of the aliphatic hydroxycarboxylic acid include an aliphatic hydroxycarboxylic acid having a linear or branched hydrocarbon group having 1 to 6 carbon atoms. Specific examples of the aliphatic hydroxycarboxylic acid include glycolic acid, lactic acid, tartronic acid, glyceric acid, hydroxybutyric acid, malic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucine acid, mevalonic acid, and pantoic acid. Can be mentioned. Among the aliphatic hydroxycarboxylic acids, examples of the dicarboxylic acid having two carboxyl groups in one molecule include tartaric acid, malic acid, and tartronic acid. Moreover, citric acid etc. can be mentioned as tricarboxylic acid which has three carboxyl groups in 1 molecule.

Examples of the aromatic carboxylic acid include a polyvalent carboxylic acid having 2 or 3 carboxyl groups in one molecule, and an aromatic hydroxycarboxylic acid having a hydroxyl group in addition to the carboxyl group on the benzene ring.
Examples of the aromatic carboxylic acid include benzoic acid. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the aromatic hydroxycarboxylic acid include salicylic acid and gallic acid.

As the aliphatic carboxylate, an aliphatic carboxylate anion is bonded to at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^+. Carboxylic acid salts can be mentioned. Specifically, dipotassium tartrate (C ₄ H ₄ K ₂ O ₆ ), potassium hydrogen tartrate (C ₄ H ₅ KO ₆ ), disodium tartrate (C ₄ H ₄ Na ₂ O ₆ ), sodium hydrogen tartrate (C ₄ H ₅ NaO _6), tartrate diammonium _{(C 4 H 12 N 2 O} 6), bitartrate ammonium _{(C 4 H 7 N 2 O} 6), potassium sodium tartrate _{(C 4 H 4 KNaO 6)} , ammonium sodium tartrate ( C ₄ H ₉ NaNO _6), potassium ammonium tartrate _{(C 4 H 9 KNO 6)} , glutaric acid disodium _{(C 5 H 6 Na 2 O} 4), sodium hydrogen glutarate _{(C 5 H 7 NaO 4)} , succinic acid disodium _{(C 4 H 4 Na 2 O} 4), dipotassium fumarate _{(C 4 H 2 K 2 O} 4), disodium fumarate _{C 4 H 2 Na 2 O 4} ), sodium hydrogen fumarate _{(C 4 H 3 NaO 4)} , dipotassium maleate _{(C 4 H 2 K 2 O} 4), potassium hydrogen maleate _{(C 4 H 3 KO 4)} , Disodium maleate (C ₄ H ₂ Na ₂ O ₄ ), sodium hydrogen maleate (C ₄ H ₃ NaO ₄ ), diammonium maleate (C ₄ H ₁₀ N ₂ O ₄ ), ammonium hydrogen maleate (C ₄ H ₇ NO ₄ ), methyl potassium malonate (C ₄ H ₅ KO ₄ ), ethyl potassium malonate (C ₅ H ₇ KO ₄ ), disodium malonate (C ₃ H ₂ Na ₂ O ₄ ), dipotassium oxalate (C ₂ K ₂ O ₄ ), potassium hydrogen oxalate (C ₂ HKO ₄ ), disodium oxalate (C ₂ Na ₂ O ₄ ), sodium hydrogen oxalate (C ₂ HNaO ₄ ) and diammonium oxalate (C ₂ H ₈ N ₂ O ₄ ).

The aromatic carboxylate is an aromatic carboxylate in which at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ is bonded to an aromatic carboxylic acid. There may be mentioned acid salts. Specifically, sodium benzoate, potassium benzoate, ammonium benzoate, sodium phthalate, potassium phthalate, ammonium phthalate, sodium hydrogen phthalate, potassium hydrogen phthalate, ammonium hydrogen phthalate, potassium hydrogen isophthalate, isophthal Examples include dipotassium acid, potassium hydrogen terephthalate, dipotassium terephthalate, sodium salicylate, potassium salicylate, and ammonium salicylate.

  As long as the organic acid anion-containing compound is a compound having the above composition, there is no problem in use, and for example, a hydrate or the like can be used. The above compounds include compounds that are hardly soluble in solvents such as water. For this reason, a treatment liquid can be prepared by adjusting the pH by adding a compound other than the above. Moreover, water and organic solvents containing organic solvents, such as alcohol, can also be used as a solvent.

  The content of the organic acid anion contained in the treatment liquid is not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately selected according to the purpose and the like. The content of the organic acid anion contained in the treatment liquid can be, for example, 0.01 mol / L or more based on the mass of the treatment liquid, and is 0.1 to 6.5 mol / L. It is preferable. Excessive reaction can be suppressed by making content of an organic acid anion into 6.5 mol / L or less.

The cation contained in the treatment liquid is at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ . The cation is preferably at least one or more selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ . Cations contained in the treatment liquid, at least Na ^+, is preferably at least one cation selected from K ^+, and the group consisting of NH ₄ ^+, is preferably a cation containing K ^+. The cation contained in the treatment liquid is obtained by dissolving a compound containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ in a solvent. Can be introduced.

The content of at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ contained in the treatment liquid is not particularly limited as long as the effect of the present invention is not impaired. It can be appropriately selected according to the purpose. The content of the cation contained in the treatment liquid can be, for example, 0.01 mol / L or more based on the mass of the treatment liquid, and is 0.1 to 13.0 mol / L. preferable.
By making the content of the cation in the treatment liquid 0.01 mol / L or more, it is selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ from fluoride. Elution of at least one cation or manganese ion can be more effectively suppressed. Excessive reaction can be suppressed by making content of the cation in a processing liquid into 13.0 mol / L or less.

The compound capable of releasing a cation is not particularly limited as long as it is a compound containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ . Examples of the compound capable of releasing a cation include an organic acid salt bonded to an organic acid anion.

When the cation is a lithium cation (Li ⁺ ), the compound containing lithium is not particularly limited as long as it can be dissolved in a solvent to release the lithium cation. Specific examples of the compound containing lithium include lithium nitrate (LiNO ₃ ), lithium sulfate (Li ₂ SO ₄ ), lithium carbonate (LiCO ₃ ), trilithium phosphate (Li ₃ PO ₄ ), lithium dihydrogen phosphate ( LiH ₂ PO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluorosilicate (Li ₂ SiF ₆ ) , Lithium fluoride (LiF), lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), lithium perchlorate (LiClO ₄ ), lithium periodate (LiIO ₄ ), lithium hydroxide ( KOH), lithium thiocyanate (LiSCN), and the like.

When the cation is a sodium cation (Na ⁺ ), the compound containing sodium is not particularly limited as long as it can be dissolved in a solvent to release the sodium cation. Specific examples of the compound containing sodium include sodium nitrate (NaNO ₃ ), sodium nitrite (NaNO ₂ ), sodium sulfate (Na ₂ SO ₄ ), sodium hydrogen sulfate (NaHSO ₄ ), and sodium thiosulfate (Na ₂ S _2). O ₃ ), sodium sulfite (Na ₂ SO ₃ ), sodium hydrogen sulfite (NaHSO ₄ ), sodium disulfite (Na ₂ S ₂ O ₅ ), sodium carbonate (NaCO ₃ ), sodium hydrogen carbonate (NaHCO ₃ ), phosphoric acid Trisodium (Na ₃ PO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), sodium diphosphate (Na ₄ P ₂ O ₇ ), triphosphate penta Sodium (Na ₅ P ₃ O ₁₀ ), sodium hexafluorophosphate (NaPF ₆ ) , Sodium tetraborate (Na ₂ B ₄ O ₇ ), sodium tetrafluoroborate (NaBF ₄ ), sodium hexafluorosilicate (Na ₂ SiF ₆ ), sodium fluoride (NaF), sodium chloride (NaCl), odor Sodium iodide (NaBr), sodium iodide (NaI), sodium chlorate (NaClO ₃ ), sodium iodate (NaIO ₃ ), sodium perchlorate (NaClO ₄ ), sodium periodate (NaIO ₄ ), sodium hydroxide (NaOH), sodium thiocyanate (NaSCN), sodium azide (NaN ₃ ) and the like.

When the cation is a potassium cation (K ⁺ ), the compound containing potassium is not particularly limited as long as it can be dissolved in a solvent to release the potassium cation. Specifically, potassium nitrate (KNO ₃ ), potassium disulfate (K ₂ S ₂ O ₇ ), potassium nitrite (KNO ₂ ), potassium sulfate (K ₂ SO ₄ ), potassium hydrogen sulfate (KHSO ₄₎ ), Potassium thiosulfate (K ₂ S ₂ O ₃ ), potassium sulfite (K ₂ SO ₃ ), potassium disulfite (K ₂ S ₂ O ₅ ), potassium carbonate (KCO ₃ ), potassium hydrogen carbonate (KHCO ₃ ), Tripotassium phosphate (K ₃ PO ₄ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ), potassium diphosphate (K ₄ P ₂ O ₇ ), triphosphorus coral potassium _{(K 5 P 3 O 10)} , potassium hexafluorophosphate _(KPF 6), potassium tetraborate _{(K 2 B 4 O 7)} , tetrafluoroboric acid potassium Beam _(KBF 4), potassium hexafluorosilicate _(K 2 _SiF 6), potassium fluoride (KF), potassium chloride (KCl), potassium bromide (KBr), potassium iodide (KI), potassium chlorate (KClO ₃ ), potassium iodate (KIO ₃ ), potassium perchlorate (KClO ₄ ), potassium periodate (KIO ₄ ), potassium hydroxide (KOH), potassium thiocyanate (KSCN), potassium cyanide (KCN), permanganese Examples include potassium acid (KMnO ₄ ), potassium hydrogen fluoride (KHF ₂ ), and potassium hexafluoromanganese (K ₂ MnF ₆ ).

When the cation is a rubidium cation (Rb ⁺ ), the compound containing rubidium is not particularly limited as long as it can be dissolved in a solvent to release the rubidium cation. Specific examples of the compound containing rubidium include rubidium nitrate (RbNO ₃ ), rubidium sulfate (Rb ₂ SO ₄ ), rubidium carbonate (RbCO ₃ ), rubidium tetrafluoroborate (RbBF ₄ ), rubidium fluoride (RbF), Examples thereof include rubidium chloride (RbCl), rubidium bromide (RbBr), rubidium iodide (RbI), rubidium perchlorate (RbClO ₄ ), and rubidium hydroxide (RbOH).

When the cation is a cesium cation (Cs ⁺ ), the compound containing cesium is not particularly limited as long as it can be dissolved in a solvent to release the cesium cation. Specific examples of the compound containing cesium include cesium nitrate (CsNO ₃ ), cesium sulfate (Cs ₂ SO ₄ ), cesium carbonate (Cs ₂ CO ₃ ), cesium hydrogen carbonate (CsHCO ₂ ), and cesium fluoride (CsF). Cesium chloride (CsCl), cesium bromide (CsBr), cesium iodide (CsI), cesium perchlorate (CsClO ₄ ), cesium hydroxide (CsOH), and the like.

When the cation is a quaternary ammonium cation (NH ₄ ⁺ ), a compound containing ammonium can be exemplified. The compound containing ammonium is not particularly limited as long as it can be dissolved in a solvent to release a quaternary ammonium cation. Specific examples of the compound containing ammonium include ammonium nitrate (NH ₄ NO ₃ ), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), ammonium hydrogen sulfate (NH ₄ HSO ₄ ), and ammonium thiosulfate ((NH ₄ ) ₂ S ₂ O ₃ ), ammonium sulfite ((NH ₄ ) ₂ SO ₃ ), ammonium hydrogen sulfite (NH ₄ HSO ₄ ), ammonium carbonate (NH ₄ CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), dihydrogen phosphate Ammonium (NH ₄ H ₂ PO ₄ ), diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), ammonium hexafluorophosphate (NH ₄ PF ₆ ), ammonium tetraborate ((NH ₄ ) ₂ B ₄ O _7), ammonium tetrafluoroborate _(NH 4 _BF 4), hexafluoro Lee ammonium _{((NH 4) 2 SiF 6} ), ammonium fluoride _{(NH 4 F), (4} Cl NH) ammonium chloride, ammonium bromide _(NH 4 Br), ammonium iodide _(NH 4 I), iodate Ammonium (NH ₄ IO ₃ ), ammonium perchlorate (NH ₄ ClO ₄ ), ammonium hydroxide (NH ₄ OH), ammonium thiocyanate (NH ₄ SCN), ammonium peroxosulfate ((NH ₄ ) ₂ S ₂ O ₈ ) , Ammonium amidosulfate (NH ₄ OSO ₂ NH ₂ ), hydroxylammonium chloride (HONH ₃ Cl), and the like.

There is no problem in use as long as it is a compound containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^+. Can be used. The above compounds include compounds that are hardly soluble in solvents such as water. For this reason, a treatment liquid can be prepared by adjusting the pH by adding a compound other than those described above. Moreover, water and organic solvents containing organic solvents, such as alcohol, can also be used as a solvent.

The treatment liquid further contains at least one cation selected from the group consisting of a solvent, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and other components other than the organic acid anion. Also good. The kind and content of other components are not particularly limited and can be appropriately selected depending on the purpose and the like. Other components may be either ionic or nonionic. Examples of other components include compounds containing Ge, Si, Sn, Ti, Zr, Mn, F, Cl, Br, I, B, Al, Ga, In, etc., and compounds containing nitrate ions. it can. When the treatment liquid includes other components, the other components may be included singly or in combination of two or more.

The pH of the treatment liquid is not particularly limited and can be appropriately selected according to the components of the treatment liquid. For example, the pH of the treatment liquid can be 0 to 14 at 25 ° C., and preferably 1 to 12. The treatment liquid contains at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic acid anion, and is represented by the general formula (I). It becomes possible to more efficiently form an organic acid salt on the surface of the fluoride.

  It is also preferable that the treatment liquid contains a potassium cation and is alkaline. When the treatment liquid contains a potassium cation and is alkaline, the pH of the treatment liquid should be higher than 7 at 25 ° C., but is preferably 8 or more, more preferably 8 to 14.

In the method for producing a fluoride phosphor, the fluoride is selected from the group consisting of fluoride, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^{+ in the} reaction mixture containing the fluoride and the treatment liquid. At least one cation and an organic acid anion. The mass ratio of the fluoride contained in the reaction mixture and the treatment liquid is not particularly limited, and can be appropriately selected according to the configuration of the treatment liquid. The mass ratio of the fluoride contained in the reaction mixture to the treatment liquid (fluoride / treatment liquid) can be, for example, 0.1 to 50% by weight.

In the reaction mixture, fluoride and at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ^+, and NH ₄ ⁺ contained in the treatment liquid come into contact with the organic acid anion. As a result, an organic acid salt is formed on the surface of the fluoride.
The contact time between the fluoride in the treatment liquid and at least one cation and organic acid anion selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ is determined according to the present invention. As long as the effect of can be obtained, there is no particular limitation. The contact time can be, for example, 1 hour or longer, and is preferably 1 to 500 hours.
The contact temperature between the fluoride and the cation and organic acid anion is not particularly limited as long as the effect of the present invention is obtained. The contact temperature can be, for example, 0 to 110 ° C.
In the reaction mixture, the contact of the fluoride with the cation and the organic acid anion may be performed in the air or in an inert gas atmosphere such as nitrogen.

  In the first step, the reaction mixture may be stirred. The method for stirring the reaction mixture is not particularly limited as long as it can relax the concentration gradient of the components dissolved in the treatment liquid, and can be appropriately selected from commonly used stirring methods. Examples of the stirring method include a method of rotating a stirring bar at a constant speed, a method of mixing a reaction mixture by pressurizing a processing liquid with a pump to generate a flow, a method of using a rotating container type mixer, and the like. be able to. Among them, the stirring method is preferably a method with a small shearing force applied to the reaction mixture. By using a stirring method having a small shearing force, a fluoride phosphor that is superior in durability can be obtained.

  When stirring the reaction mixture, the stirring may be performed continuously or intermittently. By intermittently stirring the reaction mixture, the influence of the shearing force of stirring tends to be suppressed, and a fluoride phosphor that is more durable tends to be obtained. When stirring is intermittently performed, the interval is not particularly limited, and stirring may be performed at regular intervals or may be performed at irregular intervals. When stirring is performed intermittently at regular intervals, for example, the stirring can be performed at intervals of 1 minute to 30 minutes.

  In the first step, at least a part of the treatment liquid can be removed from the reaction mixture. The reaction mixture from which at least a part of the treatment liquid is removed may be supplemented with a treatment liquid that is not in contact with fluoride (hereinafter also referred to as “unused treatment liquid”). When removing and replenishing the processing liquid (that is, replacing the processing liquid), a method of replenishing unused processing liquid after removing the processing liquid from the reaction mixture (hereinafter also referred to as “sequential replacement method”) is performed. Alternatively, the removal of the treatment liquid from the reaction mixture and the replenishment of the unused treatment liquid may be performed in a time-overlapping manner (hereinafter also referred to as “continuous exchange method”).

When removal and replenishment of the treatment liquid is performed by the sequential exchange method, the removal amount of the treatment liquid is not particularly limited. The removal amount of the treatment liquid can be, for example, 10% by weight or more of the treatment liquid contained in the reaction mixture, and is preferably 50% by weight or more.
The replenishment amount of the unused treatment liquid to the reaction mixture from which at least a part of the treatment liquid has been removed is not particularly limited and can be appropriately selected depending on the purpose and the like. The replenishment amount of the unused treatment liquid may be substantially the same as the removal amount of the treatment liquid, or may be a different amount. Substantially the same amount means that the weight ratio of the replenishment amount to the removal amount is 0.9 to 1.1.

  The method for removing the treatment liquid is not particularly limited as long as only the treatment liquid can be substantially removed from the reaction mixture. Examples of the method for removing the treatment liquid include a method for removing the supernatant of the reaction mixture by means such as decantation and suction, and a method for separating the fluoride and the treatment liquid from the reaction mixture by filtration.

  When removing and replenishing the treatment liquid by the sequential exchange method, the number of removal and replenishment of the treatment liquid is not particularly limited, and may be one time or two or more times. When the treatment liquid is exchanged twice or more, it is preferably 2 to 20 times. Further, the number of exchanges may be set as appropriate using the manganese ion concentration of the removed treatment liquid as an index.

  When the removal and replenishment of the treatment liquid is performed by the continuous exchange method, exchange conditions such as the removal amount and replenishment amount of the treatment liquid per unit time can be appropriately selected according to the purpose and the like. For example, the replacement conditions may be set as appropriate using the manganese ion concentration of the removed processing solution described later as an index.

When removing the treatment liquid in the first step, manganese ions derived from the fluoride represented by the general formula (I) may be included in the treatment liquid to be removed. By removing the treatment liquid and replenishing the treatment liquid as necessary so that the concentration of manganese ions contained in the treatment liquid to be removed falls within a predetermined range, a fluoride phosphor having superior durability can be obtained. Can be obtained.
The manganese ion concentration of the treatment liquid to be removed can be, for example, 1 ppm (w / v) or less, preferably 0.5 ppm or less, and more preferably 0.3 ppm or less. If the manganese ion concentration of the treatment liquid to be removed is 1 ppm or less, the durability of the resulting fluoride phosphor tends to be further improved. The manganese ion concentration of the treatment liquid can be measured using ICP-AES.

A treatment comprising a fluoride represented by the general formula (I) and at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic acid anion Contacting the fluoride with the cation and the organic acid anion in a reaction mixture comprising a solution includes removing at least a portion of the treatment liquid from the reaction mixture, and reducing the manganese ion concentration of the treatment liquid to be removed. It is preferably 0.5 ppm or less.

  As a method of setting the manganese ion concentration of the treatment liquid removed in the first step to 0.5 ppm or less, a method of reducing the mass ratio of fluoride to the treatment liquid in the reaction mixture, a method of removing and replenishing the treatment liquid Etc. When removing and replenishing the treatment liquid, the treatment liquid removal and replenishment method and conditions may be appropriately set so that the measured value of the manganese ion concentration of the treatment liquid to be removed is 0.5 ppm or less.

  The method for producing a fluoride phosphor may include a step of washing the resulting fluoride phosphor. The washing treatment can be performed, for example, by removing the treatment liquid from the reaction mixture, adding a washing liquid such as water, and then removing the washing liquid. What is necessary is just to select suitably the quantity of the washing | cleaning liquid used for washing | cleaning. Moreover, you may perform washing | cleaning only once or 2 times or more.

The method for producing a fluoride phosphor may further include a step of bringing the fluoride into contact with hydrogen peroxide (hereinafter also referred to as “second step”). By performing contact with hydrogen peroxide, the durability of the obtained fluoride phosphor tends to be further improved. This can be considered as follows, for example.
The fluoride phosphor is activated with tetravalent manganese ions. For example, it is considered that the durability is lowered by reducing a part of tetravalent manganese ions to divalent manganese ions. However, by treating the fluoride phosphor with hydrogen peroxide, the manganese ions are converted to 4 It can be considered that the durability is improved because it can be in a state of a valence.

  The second step may be performed independently of the first step, or may be performed in time overlap with the first step. When performing a 2nd process independently of a 1st process, it is preferable to perform a 2nd process after performing a 1st process. Moreover, when performing a 2nd process overlapped with a 1st process temporally, a 2nd process may be started from before performing a 1st process, and it may be performed simultaneously with a 1st process, You may perform a 2nd process after the start of a 1st process.

  In addition to the first step and the second step included as necessary, the method for producing a fluoride phosphor further includes post-treatment steps such as separation treatment, purification treatment, and drying treatment of the fluoride phosphor. May be.

The method for producing a fluoride phosphor may further include a step of preparing a fluoride represented by the general formula (I). The step of preparing can include a step of producing a fluoride represented by the general formula (I).
The fluoride represented by the general formula (I) contains a first complex ion containing tetravalent manganese ions, lithium (Li), sodium (Na), potassium (K) in a liquid medium containing hydrogen fluoride. ), At least one cation selected from the group consisting of rubidium (Rb), cesium (Cs) and ammonium (NH ₄ ), and at least one selected from the group consisting of Group 4 elements and Group 14 elements It can manufacture by making it contact with the 2nd complex ion containing.

The production process of the fluoride represented by the general formula (I) includes, for example, at least one selected from the group consisting of a first complex ion containing tetravalent manganese, a group 4 element, and a group 14 element, and A solution A containing at least hydrogen fluoride, a second complex ion containing fluorine ions, and at least one selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ A step of mixing the solution B containing at least a cation and hydrogen fluoride can be included.

Solution A
The solution A contains a first complex ion containing tetravalent manganese and a second complex ion containing at least one selected from the group consisting of Group 4 elements and Group 14 elements and fluorine ions. It is a hydrofluoric acid solution.

The manganese source that forms the first complex ion containing tetravalent manganese is not particularly limited as long as it is a compound containing tetravalent manganese. Specific examples of the manganese source that can constitute the first solution include K ₂ MnF ₆ , KMnO ₄ , and K ₂ MnCl ₆ . Among these, K ₂ MnF ₆ is preferable because it can be stably present in hydrofluoric acid as a MnF ₆ complex ion while maintaining the oxidation number (tetravalent) that can be activated. Among the manganese sources, those containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ are cation sources included in the second solution. Can also serve. The manganese source that forms the first complex ion may be used alone or in combination of two or more.

  The concentration of the first complex ion in the solution A is not particularly limited. The lower limit value of the first complex ion concentration in the solution A is usually 0.01% by weight or more, preferably 0.03% by weight or more, more preferably 0.05% by weight or more. The upper limit of the first complex ion concentration in the first solution is usually 50% by weight or less, preferably 40% by weight or less, more preferably 30% by weight or less.

The second complex ion includes at least one selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si), germanium (Ge), and tin (Sn). Preferably, silicon (Si) or silicon (Si) and germanium (Ge) are more preferably contained, and a silicon fluoride complex ion is further preferred.
For example, when the second complex ion includes silicon (Si), the second complex ion source is preferably a compound that includes silicon and fluorine and has excellent solubility in a solution. Specific examples of the second complex ion source include H ₂ SiF ₆ , Na ₂ SiF ₆ , (NH ₄ ) ₂ SiF ₆ , Rb ₂ SiF ₆ , and Cs ₂ SiF ₆ . Among these, H ₂ SiF ₆ is preferable because it has high solubility in water and does not contain an alkali metal element as an impurity. A 2nd complex ion source may be used individually by 1 type, and may use 2 or more types together.

  The lower limit of the second complex ion concentration in the solution A is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more. The upper limit of the second complex ion concentration in the solution A is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less.

  The lower limit value of the hydrogen fluoride concentration in the solution A is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more. Moreover, the upper limit of the hydrogen fluoride concentration in the first solution is usually 80% by weight or less, preferably 75% by weight or less, more preferably 70% by weight or less.

Solution B
The solution B contains at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and hydrogen fluoride, and other components as necessary. May be included. The solution B is obtained, for example, as an aqueous solution of hydrofluoric acid containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ .
As the sodium source containing sodium cations configurable solution _B, may be mentioned NaF, NaHF 2, NaOH, NaCl , NaBr, NaI, sodium acetate, water-soluble sodium salts such as _Na 2 CO _3.
Specific examples of the potassium source containing a potassium cation capable of constituting the solution B include water-soluble potassium salts such as KF, KHF ₂ , KOH, KCl, KBr, KI, potassium acetate, and K ₂ CO _3. . Among these, KHF ₂ is preferable because it can be dissolved without lowering the concentration of hydrogen fluoride in the solution, and the heat of dissolution is small and the safety is high.
Specific examples of the rubidium source containing a rubidium cation capable of forming the solution B include water-soluble rubidium salts such as RbF, rubidium acetate, and Rb ₂ CO ₃ .
Specific examples of the cesium source containing a cesium cation capable of forming the solution B include water-soluble cesium salts such as CsF, cesium acetate, and Cs ₂ CO ₃ .
As a sodium source containing a quaternary ammonium cation capable of forming the solution B, NH ₄ F, ammonia water, NH ₄ Cl, NH ₄ Br, NH ₄ I, ammonium acetate, (NH ₄ ) ₂ CO _{3 and the} like Mention may be made of ammonium salts. The ion source which comprises the solution B may be used individually by 1 type, or may use 2 or more types together.

The lower limit value of the hydrogen fluoride concentration in the solution B is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more. Moreover, the upper limit of the hydrogen fluoride concentration in the solution B is usually 80% by weight or less, preferably 75% by weight or less, more preferably 70% by weight or less.
Further, the lower limit value of the cation concentration in the solution B is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more. The upper limit of the concentration of at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ in the solution B is usually 80% by weight or less, preferably 70%. % By weight or less, more preferably 60% by weight or less.

The mixing method of the solution A and the solution B is not particularly limited, and the solution A may be added and mixed while stirring the solution B, or the solution B may be added and mixed while stirring the solution A. Good. Alternatively, the solution A and the solution B may be put into a container and mixed with stirring.
By mixing the solution A and the solution B, at least one selected from the group consisting of the first complex ion and Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^{+ in} a predetermined ratio. And the second complex ion react with each other to precipitate the target fluoride crystal. The precipitated crystals can be recovered by solid-liquid separation by filtration or the like. Moreover, you may wash | clean with solvents, such as ethanol, isopropyl alcohol, water, and acetone. Further, a drying treatment may be performed, and drying is usually performed at 50 ° C. or higher, preferably 55 ° C. or higher, more preferably 60 ° C. or higher, and usually 110 ° C. or lower, preferably 100 ° C. or lower, more preferably 90 ° C. or lower. The drying time is not particularly limited as long as the water adhering to the fluoride phosphor can be evaporated, and is, for example, about 10 hours.
In mixing the solution A and the solution B, the composition of the fluoride as a product becomes the target composition in consideration of the difference between the charged composition of the solution A and the solution B and the composition of the obtained fluoride. In addition, it is preferable to appropriately adjust the mixing ratio of the solution A and the solution B.

Moreover, the manufacturing process of the fluoride represented by the general formula (I) includes a first complex ion containing tetravalent manganese and a first solution containing at least hydrogen fluoride, Li ⁺ , Na ⁺ , K ^+. , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ selected from the group consisting of at least one cation selected from the group consisting of at least one cation and hydrogen fluoride, and a group consisting of Group 4 elements and Group 14 elements It can also be produced by a production process including a step of mixing a third solution containing at least one kind of the second complex ion containing fluorine ions.
By mixing the first solution, the second solution, and the third solution, a fluoride having a desired composition and a desired weight median diameter is easily produced with excellent productivity. be able to.

First Solution The first solution contains at least a first complex ion containing tetravalent manganese and hydrogen fluoride, and may contain other components as necessary. The first solution is obtained, for example, as an aqueous solution of hydrofluoric acid containing a tetravalent manganese source. The manganese source is not particularly limited as long as it is a compound containing tetravalent manganese. Specific examples of the manganese source that can constitute the first solution include K ₂ MnF ₆ , KMnO ₄ , and K ₂ MnCl ₆ . Among these, K ₂ MnF ₆ is preferable because it can be stably present in hydrofluoric acid as a MnF ₆ complex ion while maintaining the oxidation number (tetravalent) that can be activated. Among the manganese sources, one containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ is included in the Li solution. It can also serve as at least one cation source selected from the group consisting of ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ . Manganese sources constituting the first solution may be used alone or in combination of two or more.

The lower limit of the hydrogen fluoride concentration in the first solution is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more. Moreover, the upper limit of the hydrogen fluoride concentration in the first solution is usually 80% by weight or less, preferably 75% by weight or less, more preferably 70% by weight or less. When the hydrogen fluoride concentration is 30% by weight or more, the stability of the manganese source (for example, K ₂ MnF ₆ ) constituting the first solution to hydrolysis is improved, and the tetravalent manganese concentration in the first solution is increased. Fluctuations are suppressed. As a result, the amount of manganese activation contained in the resulting fluoride phosphor can be easily controlled, and variations in the luminous efficiency of the fluoride phosphor tend to be suppressed. Further, when the hydrogen fluoride concentration is 70% by weight or less, a decrease in the boiling point of the first solution is suppressed, and generation of hydrogen fluoride gas is suppressed. Thereby, the hydrogen fluoride concentration in the first solution can be easily controlled, and the variation (variation) in the particle diameter of the obtained fluoride phosphor can be effectively suppressed.

  The concentration of the first complex ion in the first solution is not particularly limited. The lower limit value of the first complex ion concentration in the first solution is usually 0.01% by weight or more, preferably 0.03% by weight or more, more preferably 0.05% by weight or more. The upper limit of the first complex ion concentration in the first solution is usually 50% by weight or less, preferably 40% by weight or less, more preferably 30% by weight or less.

Second solution The second solution contains at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and hydrogen fluoride, and is necessary. Depending on, other components may be included. The second solution is obtained, for example, as an aqueous solution of hydrofluoric acid containing at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ . As an ion source comprising a second solution configurable ions, _{specifically,} NaF, NaHF 2, NaOH, NaCl, NaBr, NaI, sodium _{acetate, Na 2 CO 3, KF,} KHF 2, KOH, KCl, KBr, KI, potassium _acetate, K ₂ CO _{3, RbF,} acetic _rubidium, Rb ₂ CO _{3, CsF,} cesium _{acetate, Cs 2 CO 3, NH 4} F, ammonia _{water, NH 4 Cl, NH 4 Br} , NH 4 I Water-soluble salts such as ammonium acetate and (NH ₄ ) ₂ CO ₃ can be mentioned. Among these, NaHF ₂ and KHF ₂ are preferable because they can be dissolved without lowering the hydrogen fluoride concentration in the solution, and because they have a low heat of dissolution and high safety. The ion source which comprises a 2nd solution may be used individually by 1 type, or may use 2 or more types together.

The lower limit of the hydrogen fluoride concentration in the second solution is usually 20% by weight or more, preferably 25% by weight or more, more preferably 30% by weight or more. Further, the upper limit value of the hydrogen fluoride concentration in the second solution is usually 80% by weight or less, preferably 75% by weight or less, more preferably 70% by weight or less.
In addition, the lower limit of the ion concentration of at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ in the second solution is usually 5% by weight or more. , Preferably 10% by weight or more, more preferably 15% by weight or more. In addition, the upper limit value of the ion concentration of at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ in the second solution is usually 80% by weight or less. , Preferably 70% by weight or less, more preferably 60% by weight or less.

Third solution The third solution contains at least a second complex ion containing at least one selected from the group consisting of Group 4 elements and Group 14 elements, and fluorine ions, and others as necessary. May be included. The third solution is obtained, for example, as an aqueous solution containing the second complex ion.
The second complex ion includes at least one selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si), germanium (Ge), and tin (Sn). Preferably, silicon (Si) or silicon (Si) and germanium (Ge) are more preferably contained, and a silicon fluoride complex ion is further preferred.

For example, when the second complex ion includes silicon (Si), the second complex ion source is preferably a compound that includes silicon and fluorine and has excellent solubility in a solution. Specific examples of the second complex ion source include H ₂ SiF ₆ , Na ₂ SiF ₆ , (NH ₄ ) ₂ SiF ₆ , Rb ₂ SiF ₆ , and Cs ₂ SiF ₆ . Among these, H ₂ SiF ₆ is preferable because it has high solubility in water and does not contain an alkali metal element as an impurity. The 2nd complex ion source which comprises a 3rd solution may be used individually by 1 type, and may use 2 or more types together.

  The lower limit of the second complex ion concentration in the third solution is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more. The upper limit of the second complex ion concentration in the third solution is usually 80% by weight or less, preferably 70% by weight or less, more preferably 60% by weight or less.

  The mixing method of the first solution, the second solution, and the third solution is not particularly limited, and the second solution and the third solution may be added and mixed while stirring the first solution, The first solution and the second solution may be added and mixed while stirring the third solution. Alternatively, the first solution, the second solution, and the third solution may be charged into a container and mixed with stirring.

By mixing the first solution, the second solution and the third solution, the first complex ions and Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ are mixed at a predetermined ratio. At least one cation selected from the group reacts with the second complex ion to precipitate a fluoride crystal represented by the general formula (I). The precipitated crystals can be recovered by solid-liquid separation by filtration or the like. Moreover, you may wash | clean with solvents, such as ethanol, isopropyl alcohol, water, and acetone. Further, a drying treatment may be performed, and drying is usually performed at 50 ° C. or higher, preferably 55 ° C. or higher, more preferably 60 ° C. or higher, and usually 110 ° C. or lower, preferably 100 ° C. or lower, more preferably 90 ° C. or lower. The drying time is not particularly limited as long as the water adhering to the fluoride can be evaporated, and is, for example, about 10 hours.

  When mixing the first solution, the second solution, and the third solution, considering the difference between the charged composition of the first to third solutions and the composition of the resulting fluoride, the product as a product is considered. It is preferable to appropriately adjust the mixing ratio of the first solution, the second solution, and the third solution so that the chemical composition becomes the target composition.

<Fluoride phosphor>
The fluoride phosphor of the present invention is a fluoride phosphor containing a fluoride represented by the following general formula (I) and an organic acid salt.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a Group 4 element and Group 14 It represents at least one element selected from the group consisting of elements, and a satisfies 0 <a <0.2.

  The fluoride phosphor is preferably obtained by the above-described method for producing a fluoride phosphor. The fluoride fluorescent substance is excellent in durability by containing a fluoride represented by the general formula (I) as a base material and containing an organic acid salt. The organic acid salt in the fluoride phosphor is preferably present in and on the surface region of the fluoride phosphor, and is present in at least part of the region from the surface of the fluoride phosphor to 1 μm in the depth direction. More preferably.

<Light emitting device>
The light emitting device of the present invention includes the fluoride phosphor and a light source that emits light in a wavelength range of 380 nm to 485 nm. The light emitting device may further include other components as necessary. When the light-emitting device contains the fluoride phosphor, the durability is excellent and excellent long-term reliability can be achieved. That is, the light-emitting device including the fluoride fluorescent material can be suitably applied to use in a harsh environment such as an illumination application because a decrease in output and a change in chromaticity are suppressed over a long period of time.

(light source)
As the light source (hereinafter also referred to as “excitation light source”), a light source that emits light in a wavelength range of 380 nm to 485 nm, which is a short wavelength region of visible light, is used. The light source preferably has an emission peak wavelength (maximum emission wavelength) in a wavelength range of 420 nm to 485 nm, more preferably in a wavelength range of 440 nm to 480 nm. Thereby, a fluoride fluorescent substance can be excited efficiently and visible light can be used effectively. In addition, a light-emitting device with high emission intensity can be provided by using an excitation light source in the wavelength range.

It is preferable to use a semiconductor light emitting element (hereinafter also simply referred to as “light emitting element”) as the excitation light source. By using a semiconductor light emitting element as the excitation light source, a stable light emitting device with high efficiency, high output linearity with respect to input, and strong against mechanical shock can be obtained.
A light emitting element that emits light in a short wavelength region of visible light can be used. For example, the blue, the green light emitting element, can be used using a nitride-based semiconductor _{(In X Al Y Ga 1-} X-Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1).

(Fluoride phosphor)
Details of the fluoride fluorescent material included in the light emitting device are as described above. For example, a fluoride phosphor can be included in a sealing resin that covers an excitation light source to constitute a light emitting device. In the light emitting device in which the excitation light source is covered with the sealing resin containing the fluoride phosphor, a part of the light emitted from the excitation light source is absorbed by the fluoride phosphor and emitted as red light. By using an excitation light source that emits light in a wavelength range of 380 nm to 485 nm, emitted light can be used more effectively. Therefore, loss of light emitted from the light emitting device can be reduced, and a highly efficient light emitting device can be provided.
The content of the fluoride phosphor contained in the light emitting device is not particularly limited and can be appropriately selected according to the excitation light source and the like.

(Other phosphors)
It is preferable that the light emitting device further includes another phosphor in addition to the fluoride phosphor. Other phosphors only need to absorb light from the light source and perform wavelength conversion to light of different wavelengths. Other phosphors can be included in a sealing resin in the same manner as the fluoride phosphor, for example, to constitute a light emitting device.

  Examples of other phosphors include nitride phosphors, oxynitride phosphors, sialon phosphors mainly activated by lanthanoid elements such as Eu and Ce; lanthanoid phosphors such as Eu, and Mn. Alkaline earth halogen apatite phosphor, alkaline earth metal borate phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate, alkaline earth mainly activated by transition metal elements Sulfide, alkaline earth thiogallate, alkaline earth silicon nitride, germanate; rare earth aluminate, rare earth silicate mainly activated by lanthanoid elements such as Ce; and mainly lanthanoid elements such as Eu It is preferably at least one selected from the group consisting of organics and organic complexes activated by.

Specific examples of other phosphors include (Ca, Sr, Ba) ₂ SiO ₄ : Eu, (Y, Gd) ₃ (Ga, Al) ₅ O ₁₂ : Ce, (Si, Al) ₆ (O, N) ₈ : Eu (β sialon), SrGa ₂ S ₄ : Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaAlSiN ₃ : Eu, (Ca, Sr) AlSiN ₃ : Eu, Lu ₃ Al ₅ O ₁₂ : Ce, (Ca, Sr, Ba, Zn) ₈ MgSi ₄ O ₁₆ (F, Cl, Br, I): Eu and the like.
By including other phosphors, light emitting devices of various colors can be provided.
When the light emitting device further includes other phosphors, the content is not particularly limited, and may be appropriately adjusted so as to obtain desired light emission characteristics.

  When the light emitting device further includes another phosphor, it preferably includes a green phosphor and absorbs light in a wavelength range of 380 nm to 485 nm. It is more preferable to include a green phosphor that emits light in the wavelength range of 495 nm to 573 nm. When the light emitting device includes a green phosphor, the light emitting device can be more suitably applied to an illumination device, a liquid crystal display device, and the like.

  When the light emitting device includes a green phosphor, the full width at half maximum of the emission spectrum of the green phosphor is 100 nm from the viewpoint of the object to be illuminated and the image showing deeper green when the light emitting device is used in an illumination device or an image display device. Or less, more preferably 70 nm or less.

As such a green phosphor, Eu whose composition formula is represented by M ¹¹ ₈ MgSi ₄ O ₁₆ X ¹¹ : Eu (M ¹¹ = Ca, Sr, Ba, Zn; X ¹¹ = F, Cl, Br, I) is used. Activated chlorosilicate phosphor, M ¹² ₂ SiO ₄ : Eu activated silicate phosphor represented by Eu (M ¹² = Mg, Ca, Sr, Ba, Zn), Si _6-z Al _z O _z N _8-z : Eu-activated β sialon phosphor represented by Eu (0 <z <4.2), M ¹³ Ga ₂ S ₄ : Eu-activated thiogallate fluorescence represented by Eu (M ¹³ = Mg, Ca, Sr, Ba) And a rare earth aluminate phosphor represented by (Y, Lu) ₃ Al ₅ O ₁₂ : Ce. Among these, green phosphors are Eu-activated chlorosilicate phosphors, Eu-activated silicate phosphors, Eu-activated β sialon phosphors, Eu-activated thiogallate phosphors, and rare-earth aluminas from the viewpoint of color tone, color reproduction range, and the like. It is preferably at least one selected from the group consisting of acid salt phosphors, and more preferably Eu-activated β sialon phosphors.

  The form of the light emitting device is not particularly limited, and can be appropriately selected from commonly used forms. As a type of the light emitting device, a shell type, a surface mount type, and the like can be given. In general, the bullet shape refers to a shape in which the shape of the resin constituting the outer surface is formed into a bullet shape. The surface-mounting type refers to a surface-mounted type that is formed by filling a light-emitting element serving as a light source and a resin in a concave storage portion. Furthermore, as a form of the light emitting device, a light emitting element as a light source is mounted on a flat mounting substrate, and a light emitting device in which a sealing resin containing a fluoride phosphor is formed in a lens shape so as to cover the light emitting element. An apparatus etc. are also mentioned.

Hereinafter, an example of a light emitting device according to an embodiment of the present invention 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 the present invention. This light-emitting device is an example of a surface-mounted light-emitting device.
The light emitting device 100 includes a light emitting element 10 of a gallium nitride compound semiconductor that emits light on a short wavelength side of visible light (for example, 380 nm to 485 nm), and a molded body 40 on which the light emitting element 10 is mounted. The molded body 40 has a first lead 20 and a second lead 30 and is integrally formed of a thermoplastic resin or a thermosetting resin. The molded body 40 has a recess having a bottom surface and side surfaces, and the light emitting element 10 is placed 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 the wire 60. The light emitting element 10 is sealed with a sealing member 50. The sealing member 50 is preferably made of a thermosetting resin such as an epoxy resin, a silicone resin, an epoxy-modified silicone resin, or a modified silicone resin. The sealing member 50 contains a fluoride phosphor 70 that converts the wavelength of light from the light emitting element 10.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Production Example 1)
16.25 g of K ₂ MnF ₆ was weighed and dissolved in 1000 g of 55 wt% HF aqueous solution, and then 450 g of 40 wt% H ₂ SiF ₆ aqueous solution was added to prepare Solution A. A solution B was prepared by weighing 195.10 g of KHF ₂ and dissolving it in 200 g of a 55 wt% HF aqueous solution.
Next, the solution A was added dropwise over about 20 minutes while stirring the solution B at room temperature. The obtained precipitate was subjected to solid-liquid separation, washed with IPA (isopropyl alcohol), and dried at 70 ° C. for 10 hours to prepare fluoride 1.

Example 1
Using the fluoride 1 obtained in Production Example 1, a fluoride phosphor 1 was produced as follows.
5.939 g of potassium tartrate was weighed and dissolved in 15 g of pure water to prepare a potassium tartrate aqueous solution. 5 g of the fluoride 1 obtained above was weighed and added to the prepared potassium tartrate aqueous solution and stirred. When the pH of this aqueous solution was measured, the value was 8. Then, it reacted at room temperature (25 degreeC) for 72 hours using the rotating container type mixer. At this time, the rotational speed of the mixer was 40 rpm. Next, after removing the supernatant potassium tartrate aqueous solution, 100 g of pure water was weighed and added to the reacted fluoride and stirred. This washed away the remaining potassium tartrate. The obtained precipitate was solid-liquid separated and then dried at 70 ° C. for 10 hours to produce the fluoride phosphor of Example 1.

<Evaluation>
(Light emission luminance characteristics)
With respect to each of the fluoride phosphors obtained as described above, normal emission luminance characteristics were measured. The light emission luminance characteristics were measured as reflection luminance under conditions of an excitation wavelength of 460 nm. The measurement results are shown below. In addition, as the fluoride phosphor of Comparative Example 1, the fluoride obtained in Production Example 1 was used as it was.

(SEM image)
An SEM image of the fluoride phosphor was obtained using a scanning electron microscope (SEM).
FIG. 2 shows an SEM image of the fluoride phosphor obtained in Example 1, and FIG. 3 shows an SEM image of the fluoride phosphor obtained in Production Example 1.

(durability)
A semiconductor laser that generates light having a wavelength of 450 nm was prepared, and the temperature was adjusted to stabilize the light output. 0.1 g of fluoride phosphor was set in the cell for measuring powder luminance, and the light emitted from the semiconductor laser was continuously irradiated to the fluoride phosphor in the cell. At this time, the current applied to the semiconductor laser was adjusted so that the light density was 3.5 W / cm ² . The change in powder luminance was measured by taking light from a portion irradiated with laser light into a photomultiplier tube. At this time, in order to remove the influence of the laser beam on the powder luminance, the laser beam reflected from the phosphor was removed using an optical filter.
FIG. 4 shows the relationship between the laser light irradiation time and powder brightness. As shown in FIG. 4, it can be seen that Example 1 is much more durable than Comparative Example 1.

  The fluoride fluorescent substance according to the present invention has excellent durability, and a light emitting device using the fluorescent substance suppresses a decrease in output and a change in chromaticity over time, and in particular, a white illumination light source using a blue light emitting diode as a light source, It can be used for light sources, LED displays, traffic lights, illumination switches, various sensors, various indicators, and the like, and exhibits excellent durability and light emission characteristics particularly in illumination applications.

  10: light emitting element, 50: sealing member, 70: fluoride phosphor, 100: light emitting device

Claims (7)

A fluoride represented by the following general formula (I), and at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ and an organic acid anion In a reaction mixture comprising a treatment liquid,
A method for producing a fluoride phosphor comprising a step of bringing a fluoride into contact with the cation and the organic acid anion.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a group 4 element and a group 14 element. Represents at least one element selected from the group consisting of group elements, and a satisfies 0 <a <0.2.)   The manufacturing method according to claim 1, wherein the contacting step includes stirring the reaction mixture.   The organic acid anion in the treatment liquid is an organic acid anion released from at least one organic acid anion-containing compound selected from the group consisting of aliphatic carboxylic acids, aromatic carboxylic acids and salts thereof. Item 3. The method according to Item 1 or 2.   The manufacturing method according to claim 1, wherein the treatment liquid contains potassium ions and is alkaline.   The production method according to claim 1, further comprising a step of bringing the fluoride into contact with hydrogen peroxide. A fluoride phosphor containing a fluoride represented by the following general formula (I) and an organic acid salt.
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, element A represents at least one cation selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M represents a group 4 element and a group 4 element. Represents at least one element selected from the group consisting of Group 14 elements, and a satisfies 0 <a <0.2.) A fluoride phosphor according to claim 6;
A light source that emits light in a wavelength range of 380 nm to 485 nm.