JP2021057604A - Method for manufacturing light-emitting device - Google Patents

Abstract

To provide a light-emitting device excellent in color reproducibility.SOLUTION: A light-emitting device 1 includes a package having a side wall forming a recess 2, a light-emitting element 4 arranged in the bottom of the recess, and a sealing member that covers the light-emitting element and is arranged in the recess. The sealing member has a first portion 9 that covers the light-emitting element and includes a phosphor, and a second portion 10 that does not substantially include the phosphor. A content of the phosphor with respect to 100 pts.mass of the resin is 30-120 pts.mass, and 1-30 pts.mass of a filler having a volume average particle size of 1 μm-100 μm with respect to 100 pts.mass of the resin is contained. The phosphor contains a phosphor having a composition represented by CaAlSiN3:Eu or (Ca,Sr)AlSiN3:Eu, a phosphor that has a composition represented by (Si,Al)6(O,N)8:Eu, contains β-sialon and emits light from green to yellow, and a fluoride phosphor containing cation, Si, Mn4+ and a fluorine atom.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a method for manufacturing a light emitting device.

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, etc. by combining this semiconductor light emitting element and a phosphor have been developed. These light emitting devices that emit light in white or 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 rays, a method that uses three types of phosphors that emit light in each of red (R), green (G), and blue (B), and a method that emits blue light. 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 of a type 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 general lighting, in-vehicle lighting, displays, and backlights for liquid crystals. Of these, the phosphor used in the light emitting device for the backlight for liquid crystals is required to have good color purity as well as luminous efficiency in order to reproduce a wide range of colors on the chromaticity coordinates. In particular, a phosphor used in a light emitting device for a backlight for a liquid crystal is required to be compatible with a color filter, and a phosphor having a narrow half-value width at the emission peak is required.

For example, as a red luminescent phosphor having an excitation band in the blue region and a narrow half-value width of the 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).

In the light emitting device, in order to protect the light emitting element, the light emitting element is sealed with a sealing material containing a phosphor, together with the light emitting element, wire bonding and other wiring.

Special Table 2009-528429

It is desired to put into practical use a ^{red-emitting Mn 4+} activated fluoride phosphor having a narrow half-value width of emission peak, which is suitable for display applications.
However, in the conventional ^{fluoride phosphor activated with Mn 4+} , manganese dioxide is produced by reacting the tetravalent manganese ions constituting the fluoride phosphor with the moisture in the air on the particle surface of the particles. As a result of the surface being colored black, it is considered that the chromaticity shifts and the light emission output decreases with time. Therefore, ^{there is a problem that it is difficult to apply the conventional fluoride phosphor activated with Mn 4+} to the backlight application for liquid crystals in which reliability is important.

From the above, it is an object of the present disclosure to provide a light emitting device in which a decrease in light emitting output is suppressed and a method for manufacturing 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 disclosure includes a package having a side wall forming a recess, a light emitting element arranged in the recess, and a sealing member for covering the light emitting element, and the sealing member is the same. It has a first portion that covers the light emitting element and contains a phosphor, and a second portion that is arranged on the first portion and does not substantially contain the phosphor. A surface having a chemical composition represented by the following general formula (I) activated by valent manganese ions and having a tetravalent manganese ion concentration lower than the tetravalent manganese ion concentration in the inner region of the phosphor particles. A light emitting device containing fluoride phosphor particles having a region.
A ₂ [M _1-b Mn ⁴⁺ _b F ₆ ] (I)
In the formula, A comprises at least ^{K +, Li +, Na +} , Rb +, a further contain an optionally cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is a It is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and b satisfies 0 <b <0.2.

The second aspect of the present disclosure has a step of preparing a package having a side wall forming a recess, a step of arranging a light emitting element in the recess, and a chemical composition represented by the following general formula (I), and has fluorescence. A sealing material containing a fluoride phosphor particle having a surface region in which the tetravalent manganese ion concentration is lower than the tetravalent manganese ion concentration in the inner region of the body particles and a binder is injected into the recess of the package. In the step, after the fluoride phosphor particles are centrifugally settled on the bottom surface side of the recess, the light emitting element is coated with the sealing material injected into the recess of the package, and the fluoride phosphor particles are contained. A step of forming one site and a second site arranged on the first site and substantially free of the fluoride phosphor particles, and curing the sealing material to form a sealing member. It is a method of manufacturing a light emitting device including a step of performing.
A ₂ [M _1-b Mn ⁴⁺ _b F ₆ ] (I)
In the formula, A comprises at least ^{K +, Li +, Na +} , Rb +, a further contain an optionally cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is a It is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and b satisfies 0 <b <0.2.

According to the present disclosure, it is possible to provide a light emitting device in which a decrease in light emitting output is suppressed and a method for manufacturing the same.

It is the 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 fluorescence micrograph of the enlarged cross section of the light emitting device which concerns on this embodiment. It is a figure which shows the PCT result of the light emitting device which concerns on this Embodiment and a comparative example.

Hereinafter, the light emitting device and the method for manufacturing the light emitting device according to the present invention will be described with reference to embodiments and examples. However, the embodiments shown below exemplify a light emitting device and a method for manufacturing the light emitting device for embodying the technical idea of the present invention, and the present invention describes the light emitting device and the manufacturing method thereof as follows. It is not limited to.
The relationship between the color name and the chromaticity coordinate, the relationship between the wavelength range of light and the color name of monochromatic light, and the like are in accordance with JIS Z8110. Specifically, 380 nm to 410 nm is purple, 410 nm to 455 nm is bluish purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is bluish green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellowish green, and 573 nm to 584 nm is yellow. 584 nm to 610 nm is yellowish red, and 610 nm to 780 nm is red.

In the present specification, the term "process" is included in this term not only as an independent process but also as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. .. Further, the numerical range indicated by using "~" indicates a range including the numerical values before and after "~" as the minimum value and the maximum value, respectively. Further, the content of each component in the sealing material is the total amount of the plurality of substances present in the sealing material unless otherwise specified, when a plurality of substances corresponding to each component are present in the sealing material. means.

<Light emitting device>
FIG. 1 is a diagram illustrating a schematic configuration of a light emitting device according to the first embodiment. The light emitting device 1 according to the first embodiment of the present disclosure will be described with reference to FIG.
The light emitting device 1 includes a package 3 having a side wall forming the recess 2, a light emitting element 4 arranged on the bottom surface of the recess 2, and sealing members 9 and 10 for covering the light emitting element 4. A first site 9 in which 9 and 10 coat the light emitting element 4 and include a fluorofluorescent particle 7 and a phosphor particle (hereinafter, also referred to as “another phosphor particle”) 8 other than the fluorofluorescent particle 7. And a second site 10 which is arranged on the first site 9 and does not substantially contain the fluorofluorescent particle 7 and the phosphor particle 8 other than the fluorofluorescent particle. The compound fluorophore particle 7 has a chemical composition represented by the following general formula (I), which is activated by tetravalent manganese ion, and has a chemical composition of 4 higher than the tetravalent manganese ion concentration in the inner region of the phosphor particle. Includes fluorofluorescent particles having a surface region with a low valent manganese ion concentration. Further, the other phosphor particles 8 are phosphor particles other than the above-mentioned fluoride phosphor particles.
A ₂ [M _1-b Mn ⁴⁺ _b F ₆ ] (I)
In the formula, A comprises at least ^{K +, Li +, Na +} , Rb +, a further contain an optionally cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is a It is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and b satisfies 0 <b <0.2.

As shown in FIG. 1, the light emitting device 1 includes a package 3 having a side wall forming a recess 2, a light emitting element 4 arranged in the recess 2, a fluoride phosphor particle 7 covering the light emitting element 4, and other light emitting devices 1. It has a first site 9 containing the phosphor particles 8 and a second site 10 arranged on the first site 9 and substantially free of the fluorescent particles.
The first site 9 and the second site 10 can be formed by curing a sealing material containing at least a binder and a phosphor, as will be described later.

The light emitting element 4 is arranged in the first reed 5 arranged at the bottom of the recess 2 of the package 3. In the light emitting element 4, the positive and negative electrodes (not shown) of the light emitting element 4 and the first metal leads 5 and the second leads 6 fixed to the package 3 are connected by wires 11 and 12. The first reed 5 and the second reed 6 form the bottom surface of the recess 2 of the package 3.

As shown in FIG. 1, the first part 9 and the second part 10 contain a common binder that also functions as a sealing member, and the interface between the first part 9 and the second part 10 is formed. It is not limited to a clearly distinguished form.

[package]
The material of the package having the side wall forming the recess is not particularly limited, and an electrically insulating material having excellent light resistance and heat resistance is preferably used. As the material of the package, resin, ceramics and the like can be used. Examples of the resin of the material of the package include a thermoplastic resin such as polyphthalamide, a thermosetting resin such as an epoxy resin, and a glass epoxy resin.

[Light emitting element]
As the light emitting element, one that emits light in a short wavelength region of visible light can be used. For example, as the blue and green light emitting elements, those using a nitride semiconductor (In _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) can be used.
As the light emitting element, it is preferable to use a light source (hereinafter, also referred to as “excitation light source”) that emits light in the wavelength range of 380 nm to 485 nm, which is a short wavelength region of visible light. The light source preferably has an emission peak wavelength (maximum emission wavelength) in the wavelength range of 420 nm to 485 nm, more preferably in the wavelength range of 440 nm to 480 nm. As a result, the phosphor can be efficiently excited and visible light can be effectively utilized. Further, by using an excitation light source in the wavelength range, it is possible to provide a light emitting device having high light emitting intensity.
By using a semiconductor light emitting device as an excitation light source, it is possible to obtain a stable light emitting device with high efficiency, high linearity of output with respect to input, and resistance to mechanical impact.

[First lead and second lead]
A first reed 5 and a second reed 6 are arranged at the bottom of the recess 2 of the package 3, and the first reed 5 and the second reed 6 form the bottom surface of the recess 2 of the package 3. The first reed 5 and the second reed 6 are also referred to as conductive members, respectively. The first reed 5 and the second reed 6 may be made of only a base material having conductivity, or may include a base material and a reflective film. The first reed 5 and the second reed 6 may be made of only a conductive reflective film. The first reed 5 and the second reed 6 may have other members interposed between the base material and the reflective film. When the conductive member includes a base material and a reflective film, the reflective film is arranged on the side on which the light emitting element 4 is placed.

(First reed and second reed base material)
When the base material of the first reed and the second reed has conductivity, for example, copper or a copper alloy can be mentioned. In addition, ceramics, epoxy resin, polyimide resin and the like can be mentioned as suitable materials for the first reed and the base material of the second reed. The first reed and the second reed are substantially plate-shaped members that form the bottom surface of the recess 2 of the package 3 and on which the light emitting element 4 and the like can be placed.
As the ceramics, alumina, aluminum nitride, mullite, silicon carbide, silicon nitride and the like can be used. Further, it is possible to use a material obtained by mixing a ceramic powder and a resin, molding the material into a sheet, laminating a ceramic green sheet obtained, and firing the material.
Further, as the base material using the epoxy resin, for example, an epoxy resin containing a glass cloth or a prepreg obtained by semi-curing an epoxy resin and a copper plate attached to the prepreg and thermosetting the epoxy resin can be used.

(Reflective film of the first reed and the second reed)
As the reflective film, for example, a material containing silver or aluminum can be used, and it is particularly preferable to use a material containing silver having a high reflectance. As the reflective film, a material containing metals such as copper, aluminum, gold, silver, tungsten, iron and nickel, iron-nickel alloy, phosphor bronze, copper containing iron and the like can be used.

[Insulation member]
It is preferable that the light emitting element 4, the first lead 5, the second lead 6, and the wires 11 and 12 are covered with an insulating member (not shown). The insulating member is preferably provided so as to be continuous on the light emitting element 4, the first reed 5, the second reed 6, and the wires 11 and 12. Here, "provided to be continuous" is provided in a layered (film-like) manner with respect to an object composed of a light emitting element 4, a first lead 5, a second lead 6, and wires 11 and 12. Or, the powdery or needle-shaped insulating member is provided on the light emitting element 4, the first lead 5, the second lead 6, and the wires 11 and 12 substantially as a whole, while the insulating member has a partial gap. Including the state of being. The insulating member alters the metal constituting the light emitting element 4, the first lead 5, the second lead 6, and the wires 11 and 12, particularly the silver constituting the first lead 5 and the second lead 6. It is possible to block the gas, water, fluorine (F) contained in the phosphor, etc. that have an action. When fluorine contained in the phosphor reacts with silver contained in the conductive member or the like, silver fluoride is formed, so that the black silver fluoride may absorb the light generated from the light emitting element to reduce the light output. With the insulating member, deterioration of silver contained in the first reed 5 and the second reed 6 and the like can be efficiently suppressed, and the light output efficiency can be improved. Further, the insulating member functions like a passivation film and blocks gas such as sulfur (S) and oxygen (O), moisture, fluorine (F) contained in the phosphor, and the like, and the first lead 5 and It is possible to suppress the migration of silver contained in the second lead 6 and the like.

(Insulation member)
The material of the insulating member is preferably a translucent material, and it is preferable to use an inorganic compound. Specifically, the material of the insulating member is SiO ₂ , Al ₂ O ₃ , TIO ₂ , ZrO ₂ , ZnO ₂ , Nb ₂ O ₃ , MgO, SrO, In ₂ O ₃ , TaO ₂ , HfO, SeO, Y. ₂ O ₃ oxide such or, SiN, AlN, nitride such as AlON, fluorides MgF ₂ and the like. One of these may be used alone, or two or more thereof may be used in combination. Alternatively, two or more layers of insulating members containing one or more materials may be laminated.

The thickness of the insulating member is preferably such that light loss does not occur due to multiple reflections at each interface of the conductive member, the insulating member, the first portion 9, the second portion 10, and the like. On the other hand, the insulating member is thick enough to block the gas, moisture, fluorine (F) contained in the phosphor and the like so as not to react the conductive member with the fluorine (F) contained in the gas, moisture and phosphor. Is necessary. The thickness of the insulating member varies slightly depending on the material of each member constituting the light emitting device. The thickness of the insulating member is preferably about 1 nm to 100 nm. The thickness of the insulating member is more preferably 1 nm to 50 nm, further preferably 2 nm to 25 nm, and particularly preferably 3 nm to 10 nm.

As the insulating member, it is preferable to form a film (layer) made of an inorganic compound on the conductive member, the wires 11 and 12, and the light emitting element 4 by sputtering or vapor deposition. Further, it is more preferable that the insulating member forms a film (layer) by an atomic layer deposition method (Atomic Layer Deposition). The atomic layer deposition method is a method of forming a layer of reaction components for each atomic layer. When an insulating member (membrane) is formed by the atomic layer deposition method, unlike the conventional sputtering and vapor deposition methods, the reaction components are uniformly supplied to the target even when obstacles are present, and the film thickness is uniform. And a good quality protective film having a uniform film quality can be formed. Since the insulating member (film) formed by the atomic layer deposition method has a thin film thickness and can suppress the absorption of light, it is possible to provide a light emitting device having a high light output in the initial characteristics.

Next, an example of forming an insulating member (film) of _{aluminum oxide (Al 2} O ₃ ) by the atomic layer deposition method will be described.
First, trimethylaluminum (hereinafter, also referred to as "TMA") gas is introduced into the surfaces of the conductive members, wires 11 and 12 and the light emitting element 4 which are objects, and are present in the conductive members, wires 11 and 12 and the light emitting element 4. The OH group to be produced reacts with the TMA gas (first reaction). Next, the surplus gas is exhausted. _{Next, H 2} O gas is introduced into the object, and TMA that has reacted with the OH group in the first reaction reacts with H ₂ O (second reaction). Next, the surplus gas is exhausted. After that, the first reaction, the exhaust, the second reaction, and the exhaust are regarded as one cycle, and by repeating this cycle a plurality of times, the aluminum oxide (Al ₂ O ₃ ) film having a desired thickness is formed on the conductive member, the wire 11, and the wire 11. It is formed on the surface of 12 and the light emitting element 4.

[First part and second part]
The first portion 9 and the second portion 10 form a sealing member for sealing the light emitting element 4. The first site 9 and the second site 10 are formed using a sealing material containing at least a binder and a phosphor. The first portion 9 and the second portion 10 emit light of fluoride phosphor particles 7 and other phosphor particles 8 after injecting a sealing material into the recess 2 of the package 3 in which the light emitting element 4 is arranged. After centrifugally settling on the element 4 side, the binder is cured to coat the light emitting element 4, and the first site 9 containing the fluoride phosphor particles 7 and the other phosphor particles 8 and the first portion 9 thereof. It is placed on the site 9 to form a second site 10 that is substantially free of fluoride phosphor particles 7 and other phosphor particles 8.

The first site 9 has a chemical composition represented by the general formula (I), and has a surface region in which the tetravalent manganese ion concentration is lower than the tetravalent manganese ion concentration in the inner region of the phosphor particles. Includes fluoride phosphor particles. The fluorophore containing fluoride phosphor particles is sufficiently dispersed in a sealing material containing at least a binder and a fluorophore, and the fluorophore does not become too densely clogged by centrifugal sedimentation. The encapsulating material is layered and deposited on top to form the first site 9 and the second site 10 before curing.

Since the first portion 9 and the second portion 10 are configured to contain a common binder, it is possible to suppress a decrease in the light emission output from the light emitting element and also suppress a chromaticity deviation of the light emitting device. it can. Further, since the light emitting element 4 is covered with the fluoride phosphor particles 7 and other phosphor particles 8, the light emitted from the light emitting element can be efficiently wavelength-converted by the phosphor, and the light emission can be efficiently performed. Can be released.

In the conventional ^{fluoride phosphor activated with Mn 4+} , on the particle surface, the tetravalent manganese ions constituting the fluoride phosphor react with the moisture in the air to generate manganese dioxide, and the particle surface is formed. As a result of being colored black, the chromaticity shift may occur or the light emission output may decrease.
In the light emitting device of this embodiment, the moisture in the air entering from the interface between the light emitting surface formed by the second portion 10 and the package 3 is blocked by the second portion 10. Since it is blocked by the second site 10, moisture in the air does not easily reach the fluoride phosphor particles 7 and other phosphor particles 8 contained in the first site 9, and is contained in the first site 9. The reaction between the tetravalent manganese ions contained in the fluoride phosphor activated with Mn ⁴⁺ and water can be suppressed, and the formation of manganese dioxide can suppress the particle surface from being colored black. .. Therefore, the light emitting device of this embodiment can suppress a decrease in light emitting output and a chromaticity shift, and can achieve sufficient durability in a long-term reliability test.
Further, in the light emitting device of the present embodiment, the second portion 10 can suppress the moisture in the air from reaching the fluoride phosphor contained in the first portion 9, and the fluoride phosphor is deteriorated. Can be suppressed. When the fluoride phosphor is deteriorated, Mn ⁴⁺ or F contained in the fluoride phosphor ^- is eluted, although binder constituting the first portion 9 and the second portion 10 of the may deteriorate, Since the deterioration of the fluoride phosphor can be suppressed, the deterioration of the first site 9 and the second site 10 can also be suppressed.

The thickness of the second portion is preferably 1/10 or more of the thickness of the entire sealing member immediately above the light emitting element. Immediately above the light emitting element, the thickness of the second portion is one tenth or more of the thickness of the entire sealing member, so that the light converted by the phosphor can be efficiently emitted to the outside of the light emitting device. it can.

The thickness of the second portion is preferably one-fourth or more of the thickness of the entire sealing member immediately above the light emitting element. Immediately above the light emitting element, the thickness of the second portion is one-fourth or more of the thickness of the entire sealing member, so that the moisture in the air is blocked by the second portion 10 and the first It is difficult to reach the phosphor contained in the site, and the reaction between the tetravalent manganese ion contained in the fluoride phosphor activated by ^{Mn 4+ contained in the first site and water can be suppressed, and the dioxide dioxide can be suppressed.} The formation of manganese can efficiently prevent the surface of the particles from being colored black.

[Encapsulation material]
The sealing member including the first portion and the second portion is formed by a sealing material containing at least a binder and a phosphor, which constitute the sealing member by curing. The sealing material constituting the sealing member by curing may further contain a filler having a volume average particle diameter of 1 μm to 20 μm. Further, the sealing material may contain nanofillers having an average particle size of primary particles of 5 nm to 20 nm.

(Binder)
The binder contained in the sealing material forming the sealing member is preferably a translucent material capable of transmitting light from the light emitting element. Examples of the binder include glass, resin and the like. The binder is preferably a resin. Specific examples of the resin include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin and the like. The resin is preferably at least one resin selected from the group consisting of silicone resin, modified silicone resin, epoxy resin, modified epoxy resin and acrylic resin. Further, the resin may be a silicone resin, an epoxy resin, a urea resin, a fluororesin, or a resin in combination thereof. Among them, as the resin, it is preferable to use a modified silicone resin, and it is preferable to use a phenyl silicone resin in which a phenyl group is introduced into a part of the side chain of the polysiloxane.

When the binder in the sealing material is a resin, the resin content in the sealing material is preferably 5 to 95% by mass with respect to 100% by mass of the sealing material. The resin content in the sealing material is more preferably 35 to 85% by mass, still more preferably 40 to 80% by mass, and particularly preferably 45 to 75% by mass with respect to 100% by mass of the sealing material. When the binder in the sealing material is a resin and the resin content is 5 to 95% by mass with respect to 100% by mass of the sealing material, a member such as a light emitting element arranged in the recess. Can be stably protected by a sealing member formed by curing the sealing material. Further, when the content of the resin in the sealing material is within the above range, a sufficient amount of phosphor for coating the light emitting element can be contained in the first portion.

(Fluoride phosphor)
The fluoride has a chemical composition represented by the following general formula (I), which is activated by tetravalent manganese ions, and the concentration of tetravalent manganese ions is lower than the concentration of tetravalent manganese ions in the internal region. Includes fluoride phosphor particles with a surface region.
A ₂ [M _1-b Mn ⁴⁺ _b F ₆ ] (I)
In the formula, A comprises at least ^{K +, Li +, Na +} , Rb +, a further may contain an cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is a Group 4 element And at least one element selected from the group consisting of Group 14 elements, where b satisfies 0 <b <0.2.

Fluorescent phosphor particles having a chemical composition represented by the general formula (I) and having a surface region having a tetravalent manganese ion concentration lower than the tetravalent manganese ion concentration in the internal region have a half-value width of the emission spectrum. Is a narrow red light emitting phosphor and has excellent moisture resistance, and the light emitting device of the present embodiment including this can show sufficient durability in a long-term reliability test. This can be considered, for example, as follows.
Generally, in a fluoride phosphor represented by the general formula (I), manganese dioxide is produced by reacting tetravalent manganese ions constituting the fluoride with water in the surface region of the particles to generate particles. As a result of the surface being colored black, it is considered that the light emission output is lowered and the chromaticity shift occurs. For this reason, it is not possible to achieve sufficient durability in a long-term reliability test, and there is a problem that it is difficult to apply it to an application in which reliability is important.
However, in the fluoride phosphor used in this embodiment, the concentration of tetravalent manganese ions in the surface region of the particles is suppressed to be lower than the concentration in the internal region. Therefore, it is considered that the production of manganese dioxide on the particle surface is suppressed, and the decrease in luminescence output and the chromaticity shift are suppressed over a long period of time. It is considered that excellent long-term reliability can be achieved by this.

The particle size distribution and particle size distribution of the fluoride phosphor having the chemical composition represented by the general formula (I) are not particularly limited, but it is preferable to show a single peak particle size distribution from the viewpoint of emission intensity and durability. It is more preferable that the particle size distribution is a single peak with a narrow distribution width. Further, the surface area and bulk density of the fluoride phosphor are not particularly limited.

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

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

A in the general formula (I) ^{contains at least potassium ion (K +} ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (Cs +). It is a cation that may further contain at least one selected from the group consisting of NH ₄ ^+). The content of potassium ion in A is not particularly limited, and is preferably 50 mol% or more, more preferably 80 mol% or more, for example.

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), from the viewpoint of light emission characteristics. It is preferably at least one selected from the group consisting of hafnium (Hf), silicon (Si), germanium (Ge) and tin (Sn), preferably silicon (Si), or silicon (Si) and germanium (Ge). Is more preferable, and silicon (Si), or silicon (Si) and germanium (Ge) are further preferable.
When M contains silicon (Si), or silicon (Si) and germanium (Ge), at least a portion of Si and Ge contains Group 4 elements, including Ti, Zr and Hf, as well as C and Sn. It may be substituted with at least one selected from the group consisting of Group 14 elements. In that case, the total content of Si and Ge in M is not particularly limited, and is preferably 50 mol% or more, more preferably 80 mol% or more, for example.

The fluoride phosphor particles have a lower concentration of tetravalent manganese ions than the internal region formed in the first step described in detail below and the internal region, and the second step and the third step, or the third step. It has a surface area formed in the second step.

In the surface region of the fluoride phosphor particles, the concentration of tetravalent manganese ions is lower than that in the internal region. This surface region may be partitioned from the internal region at a clear interface, such as a two-layer structure, or is not partitioned from the internal region at a clear interface, gradually from the inside to the outside of the surface region. The embodiment may be such that the concentration of tetravalent manganese ions is lowered.
The fluoride phosphor particles obtained by the production method described later have a wider color reproduction range of the image display device than the light emitting device using the conventional fluoride phosphor in which the entire particles are activated with tetravalent manganese ions. Even when the surface of the fluoride phosphor particles is eluted with humidity, the tetravalent manganese ion is absent or abundant in the surface region, so that it is derived from the tetravalent manganese ion. The production of manganese dioxide is suppressed. As a result, blackening of the surface of the fluoride phosphor particles can be suppressed, and a decrease in emission intensity can be suppressed.

The average value of the concentration of tetravalent manganese ions present in the surface region of the fluoride phosphor particles is preferably 30% by mass or less with respect to the average value of the concentration of tetravalent manganese ions in the internal region. Further, the concentration of tetravalent manganese ions present in the surface region is more preferably 25% by mass or less, still more preferably 20% by mass or less, of the concentration of tetravalent manganese ions in the inner region. On the other hand, the concentration of tetravalent manganese ions in the surface region can be 0.5% by mass or more of the internal region. As described above, the moisture resistance is improved by bringing the concentration of tetravalent manganese ions close to zero, but as the concentration of tetravalent manganese ions in the surface region decreases, light emission occurs in the surface region of the fluoride phosphor particles. This is because the proportion of regions that do not contribute to the above increases, and the emission intensity tends to decrease.

The thickness of the surface region depends on the particle size of the fluoride phosphor, but is preferably about 1/10 to 1/50 of the average particle size. For example, when the average particle size of the fluoride phosphor as a whole is 20 μm to 40 μm, the thickness of the surface region is 2 μm or less.

In the fluoride phosphor, the elution amount of tetravalent manganese ions when put into pure water in an amount 1 to 5 times the mass of the fluoride phosphor is, for example, in the range of 0.05 ppm to 3 ppm at 25 ° C. Is prepared to be. The elution amount of tetravalent manganese ions under the above conditions is preferably in the range of 0.1 to 2.5 ppm, more preferably in the range of 0.2 to 2.0 ppm. This is because the moisture resistance improves as the elution amount of tetravalent manganese ions decreases, but the emission intensity tends to decrease as described above as the proportion of the surface region containing less tetravalent manganese ions increases. .. The amount of manganese ion eluted is 1 to 5 times (preferably 3 times) the mass of the fluoride phosphor in pure water, the fluoride phosphor is added, and the mixture is stirred at 25 ° C. for 1 hour and then reduced. The supernatant obtained by adding an agent and eluting manganese ions in the liquid can be collected and measured by quantitative analysis by ICP luminescence analysis.

By configuring the fluoride phosphor as described above, the emission output is reduced and the chromaticity is accompanied by coloring due to the formation of manganese dioxide due to the tetravalent manganese ions when the fluoride phosphor comes into contact with water. Since the displacement can be suppressed, a fluoride phosphor having high moisture resistance can be realized.

The moisture resistance of the fluoride phosphor can be confirmed by the discoloration of the pressure cooker test (PCT). In addition, the moisture resistance can be evaluated by, for example, the maintenance rate of the emission brightness after the water resistance test, that is, the ratio (%) of the emission brightness after the water resistance test to the emission brightness before the water resistance test. The maintenance rate of the emission brightness after the water resistance test is preferably 85% or more, and more preferably 90% or more.
Here, the water resistance test is specifically carried out by putting the fluoride phosphor into water in an amount of 1 to 5 times (preferably 3 times) the mass thereof and stirring at 25 ° C. for 1 hour.

(Method for producing fluoride phosphor)
The fluoride phosphor of this embodiment has a chemical composition represented by the general formula (I), and has a surface region in which the tetravalent manganese ion concentration is lower than the tetravalent manganese ion concentration in the internal region. It is a body, and its manufacturing method includes a first step of forming an internal region (hereinafter, also referred to as a “core portion”), a second step of forming a surface region, and a third step.

(First step)
The method for producing a fluoride phosphor includes a step of preparing a fluoride phosphor having a chemical composition represented by the general formula (I). This preparation step can include a step of producing a fluoride phosphor having a chemical composition represented by the general formula (I).
The fluoride phosphor having a chemical composition represented by the general formula (I) is a first complex ion containing tetravalent manganese ion and at least potassium ion (K ⁺ ) in a liquid medium containing hydrogen fluoride. At least one selected from the group consisting of lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ^+). It can be produced by contacting a cation which may be contained with a second complex ion containing at least one selected from the group consisting of Group 4 elements and Group 14 elements.

The fluoride phosphor having a chemical composition represented by the general formula (I) is selected from, for example, at least a group consisting of a first complex ion containing tetravalent manganese, a group 4 element and a group 14 element. one, and second complex ion containing fluorine ions, as well as a solution a containing at least hydrogen fluoride comprises at least ^{K +, Li +, Na +} , Rb +, selected from Cs ⁺ and the group consisting of _NH ^{4 +} The production is carried out by a production method including a step of mixing a cation containing at least one of the above-mentioned ions and a solution b containing at least hydrogen fluoride (hereinafter, also referred to as "first fluoride phosphor production step"). Can be done.

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

The manganese source for forming the first complex ion containing a tetravalent manganese ion is not particularly limited as long as it is a manganese-containing compound. Specific examples of the manganese source in which the solution a can be formed include K ₂ MnF ₆ , KMnO ₄ , K ₂ MnCl _{6, and the} like. Among them, while maintaining the oxidation number that can be activated by (tetravalent), since such can exist stably in hydrofluoric acid as MnF ₆ complex ions, K ₂ MnF ₆ is preferred. Among the manganese sources, at least potassium ion (K ⁺ ) is contained, and lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH _{4) are contained.} Those containing a cation which may further contain at least one selected from the group consisting of ^{+) can also serve as a cation source contained in the solution b.} As the manganese source forming the first complex ion, one type may be used alone, or two or more types may be used in combination.

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

The second complex ion may include at least one selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si), germanium (Ge) and tin (Sn). Preferably, it contains silicon (Si), or silicon (Si) and germanium (Ge), and more preferably a silicon fluoride complex ion.
For example, when the second complex ion contains silicon (Si), the second complex ion source is preferably a compound containing silicon and fluorine and having 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 , Cs ₂ SiF _{6, and the} like. _{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. As the second complex ion source, one type may be used alone and two or more types may be used in combination.

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

The lower limit of the hydrogen fluoride concentration in the solution a is usually 20% by mass or more, preferably 25% by mass or more, and more preferably 30% by mass or more. The upper limit of the hydrogen fluoride concentration in the solution a is usually 80% by mass or less, preferably 75% by mass or less, and more preferably 70% by mass or less.

Solution b
Solution b contains at least potassium ion (K ⁺ ) and is composed of lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ⁺ ). It may further contain at least one cation and hydrogen fluoride which may further contain at least one selected from the group, and may contain other components as needed. Solution b contains, for example, at least potassium ion (K ⁺ ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ^+). ) Is obtained as an aqueous solution of hydrofluoric acid containing a cation which may further contain at least one selected from the group consisting of.
Specific examples of the potassium ion source that can form the solution b include water-soluble potassium salts such as _{KF, KHF 2} , KOH, KCl, KBr, KI, potassium acetate, and K ₂ CO _{3. Of these, KHF 2} is preferable because it can be dissolved without lowering the concentration of hydrogen fluoride in the solution, and the heat of solution is small and the safety is high.
Examples of the sodium ion source that can form the solution b include water-soluble sodium salts such _{as NaF, NaHF 2} , NaOH, NaCl, NaBr, NaI, sodium acetate, and Na ₂ CO _3.
Specific examples of the rubidium ion source that can form the solution b include water-soluble rubidium salts such as _{RbF, rubidium acetate, and Rb 2} CO _3.
Specific examples of the cesium ion source that can form the solution b include water-soluble cesium salts such as _{CsF, cesium acetate, and Cs 2} CO _3.
Examples of the ammonium ion source that can form the solution b include _{water-soluble ammonium salts such as NH 4} F, aqueous ammonia, NH ₄ Cl, NH ₄ Br, NH ₄ I, ammonium acetate, and (NH ₄ ) ₂ CO _3. it can. As the ion source constituting the solution b, one type may be used alone or two or more types may be used in combination.

The lower limit of the hydrogen fluoride concentration in the solution b is usually 20% by mass or more, preferably 25% by mass or more, and more preferably 30% by mass or more. The upper limit of the hydrogen fluoride concentration in the solution b is usually 80% by mass or less, preferably 75% by mass or less, and more preferably 70% by mass or less.
The lower limit of the cation concentration in the solution b is usually 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more. It also contains at least potassium ion (K ⁺ ) in solution b, lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ⁺ ). The upper limit of the cation concentration that may further contain at least one selected from the group consisting of is usually 80% by mass or less, preferably 70% by mass or less, and more preferably 60% by mass or less.

The method for mixing 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. .. Alternatively, the solution a and the solution b may be put into a container and mixed by stirring.
By mixing solution a and solution b, the first complex ion and at least potassium ion (K ⁺ ) are contained in a predetermined ratio, and lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), and rubidium ion (Rb) are contained. ^+), cesium ion (Cs ⁺⁾ and the also good cationic further comprise at least one member selected from the group consisting of ammonium ion (NH 4 ^_+), fluoride fluorescence of the second complex ion and the objective react Body crystals precipitate. The precipitated crystals can be recovered by solid-liquid separation by filtration or the like. Further, it may be washed with a solvent such as ethanol, isopropyl alcohol, water and acetone. Further drying treatment may be performed, and it is usually dried 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.
When mixing the solution a and the solution b, the composition of the fluoride phosphor as a product is intended in consideration of the deviation between the prepared composition of the solution a and the solution b and the composition of the obtained fluoride phosphor. It is preferable to appropriately adjust the mixing ratio of the solution a and the solution b so as to obtain the composition.

Further, in the process for producing a fluoride phosphor having a chemical composition represented by the general formula (I), a first solution containing at least a first complex ion containing tetravalent manganese and hydrogen fluoride, and at least potassium. It contains an ion (K ⁺ ) and is selected from the group consisting of lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ^+). A second complex containing a second solution containing at least a cation and hydrogen fluoride which may further contain at least one, and at least one selected from the group consisting of Group 4 and Group 14 elements and a fluorine ion. It can also be produced by a production method including a step of mixing with a third solution containing at least ions (hereinafter, also referred to as “second fluoride phosphor production step”).
By mixing the first solution, the second solution, and the third solution, a fluoride phosphor having a desired composition and a desired weight median diameter can be easily produced with excellent productivity. Can be manufactured.

First Solution The first solution contains at least a first complex ion containing tetravalent manganese ions and hydrogen fluoride, and may contain other components if 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 manganese. Specific examples of the manganese source that can form the first solution include K ₂ MnF ₆ , KMnO ₄ , K ₂ MnCl _{6, and the} like. Among them, while maintaining the oxidation number that can be activated by (tetravalent), since such can exist stably in hydrofluoric acid as MnF ₆ complex ions, K ₂ MnF ₆ is preferred. Among the manganese source includes at least ^{K +, Li +, Na +} , Rb +, Cs + and at least one further comprise those containing good cations are also selected from the group consisting of _NH ^{4 +} is the includes at least a ^{K +} contained in the second ^{solution, Li +, Na +, Rb} +, can also serve as the good cation source at least one further comprise selected from Cs ⁺ and the group consisting of _NH ^{4 +.} The manganese source 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 mass or more, preferably 25% by mass or more, and more preferably 30% by mass or more. The upper limit of the hydrogen fluoride concentration in the first solution is usually 80% by mass or less, preferably 75% by mass or less, and more preferably 70% by mass or less. If the hydrogen fluoride concentration is 30 mass% or more, manganese source constituting a first solution (e.g., K 2 _{MnF 6)} improved stability to hydrolysis of tetravalent manganese concentration in the first solution Fluctuations are suppressed. As a result, the amount of manganese-attached activity contained in the obtained fluoride phosphor can be easily controlled, and there is a tendency that variation (variation) in luminous efficiency in the fluoride phosphor can be suppressed. Further, when the hydrogen fluoride concentration is 70% by mass or less, the decrease in the boiling point of the first solution is suppressed, and the generation of hydrogen fluoride gas tends to be suppressed. Thereby, the hydrogen fluoride concentration in the first solution can be easily controlled, and the variation (variation) in the particle size 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 of the concentration of the first complex ion in the first solution is usually 0.01% by mass or more, preferably 0.03% by mass or more, and more preferably 0.05% by mass or more. The upper limit of the concentration of the first complex ion in the first solution is usually 50% by mass or less, preferably 40% by mass or less, and more preferably 30% by mass or less.

Second solution The second solution comprises at least ^{K +, Li +, Na +} , Rb +, Cs + and further may contain an cation and fluoride of at least one selected from the group consisting of _NH ^{4 +} It may contain at least hydrogen and, if necessary, other components. Second solution, for example, at least include ^{K +, Li +, Na +} , Rb +, hydrogen fluoride containing at least one further may contain an cation selected from Cs ⁺ and the group consisting of _NH ^{4 +} Obtained as an aqueous solution of acid. As an ion source comprising a second solution configurable ions, _{specifically,} in addition to the salt containing KF, KHF 2, KOH, KCl , KBr, KI, potassium _acetate, potassium etc. K 2 CO _3, NaF, NaHF ₂ , NaOH, NaCl, NaBr, NaI, Sodium Acetate, Na ₂ CO ₃ , RbF, Rubidium Acetate, Rb ₂ CO ₃ , CsF, Cesium Acetate, Cs ₂ CO ₃ , NH ₄ F, Ammonium Water, NH ₄ Water-soluble salts such as Cl, NH ₄ Br, NH ₄ I, ammonium acetate, (NH ₄ ) ₂ CO _{3 and the like can be mentioned. Above all, it is preferable to use at least KHF 2} 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. _{NaHF 2} is an ion source other than potassium. preferable. As the ion source constituting the second solution, one type may be used alone or two or more types may be used in combination.

The lower limit of the hydrogen fluoride concentration in the second solution is usually 20% by mass or more, preferably 25% by mass or more, and more preferably 30% by mass or more. The upper limit of the hydrogen fluoride concentration in the second solution is usually 80% by mass or less, preferably 75% by mass or less, and more preferably 70% by mass or less.
Also includes at least ^{K +} in the second ^{solution, Li +, Na +, Rb} +, Cs + and _NH ^{4 +} at least one further comprise the lower limit of the ion concentration may be cation selected from the group consisting of Is usually 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more. Also includes at least ^{K +} in the second ^{solution, Li +, Na +, Rb} +, Cs + and at least one further comprise the upper limit of the ion concentration may be cation selected from the group consisting of _NH ^{4 +} Is usually 80% by mass or less, preferably 70% by mass or less, and more preferably 60% by mass 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 if necessary, other May contain the components of. The third solution is obtained, for example, as an aqueous solution containing the following second complex ion.
The second complex ion may include at least one selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si), germanium (Ge) and tin (Sn). Preferably, it contains silicon (Si), or silicon (Si) and germanium (Ge), and more preferably a silicon fluoride complex ion.

For example, when the second complex ion contains silicon (Si), the second complex ion source is preferably a compound containing silicon and fluorine and having 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 , Cs ₂ SiF _{6, and the} like. _{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. As the second complex ion source constituting the third solution, one type may be used alone and two or more types may be used in combination.

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

The method of mixing 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. Further, the first solution, the second solution and the third solution may be put into a container and mixed by stirring.

By mixing the first solution, the second solution and the third solution, the first complex ion and at least K ⁺ are contained in ^{a predetermined ratio, and Li +} , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^A cation that may further contain at least one selected from the group consisting of + reacts with the second complex ion to precipitate a fluoride crystal having the desired chemical composition represented by the general formula (I). To do. The precipitated crystals can be recovered by solid-liquid separation by filtration or the like. Further, it may be washed with a solvent such as ethanol, isopropyl alcohol, water and acetone. Further drying treatment may be performed, and it is usually dried 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 crystals can be evaporated, and is, for example, about 10 hours.

When mixing the first solution, the second solution, and the third solution, the fluorine as a product is produced in consideration of the difference between the prepared composition of the first to third solutions and the composition of the obtained fluoride. It is preferable to appropriately adjust the mixing ratio of the first solution, the second solution and the third solution so that the composition of the fluoride phosphor is the desired composition.

(Second step)
In the second step, a reducing agent is added to the dispersion containing the fluoride crystals obtained in the first step. It is preferable that at least a part of the tetravalent manganese ion contained in the first complex ion contained in the dispersion is reduced to the divalent manganese ion by adding the reducing agent. In the second step, 90 mol% or more of the tetravalent manganese ion contained in the first complex ion is preferably reduced, and more preferably 95 mol% or more is reduced.

The reducing agent is not particularly limited as long as it can reduce the first complex ion. Specific examples of the reducing agent include hydrogen peroxide and oxalic acid.
Among these, it is used in the manufacturing process because it has little effect on fluoride crystals such as dissolving fluoride crystals and can reduce the first complex ion and finally decomposes into water and oxygen. Hydrogen peroxide is preferable because it is easy and has a small environmental load.

The amount of the reducing agent added is not particularly limited. The amount of the reducing agent added can be appropriately selected depending on, for example, the content of the first complex ion contained in the dispersion, but the amount of the reducing agent added is such that the hydrogen fluoride concentration in the dispersion does not fluctuate much. Is preferable. Specifically, the amount of the reducing agent added is preferably 3 equivalents or more, preferably 5 equivalents or more, based on the content of the first complex ion contained in the dispersion other than the fluoride crystals. Is more preferable.
Here, 1 equivalent means the number of moles of the reducing agent required to reduce the tetravalent manganese ion contained in 1 mol of the first complex ion to the divalent manganese ion.

The second step may include adding a reducing agent to the dispersion and then mixing. The mixing means for mixing the dispersion and the reducing agent can be appropriately selected from the commonly used mixing means depending on the reaction vessel and the like.
The temperature in the second step is not particularly limited. For example, the reducing agent can be added in a temperature range of 15 to 40 ° C., preferably in a temperature range of 23 to 28 ° C.
Further, the atmosphere in the second step is not particularly limited. The reducing agent may be added in a normal atmosphere, or may be carried out in an atmosphere of an inert gas such as nitrogen gas.
Further, the reaction time in the second step is not particularly limited. For example, 1 to 30 minutes, more preferably 3 to 15 minutes.

(Third step)
In the third step, the fluoride crystals in the dispersion to which the reducing agent was added contained the second complex ion and at least potassium ion (K ⁺ ) in the presence of hydrogen fluoride, and lithium ion (Li). ^A cation that may further contain at least one selected from the group consisting of +), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ^+). Contact to obtain a fluoride phosphor. In the presence of hydrogen fluoride, it contains fluoride crystals and a second complex ion and at least potassium ion (K ⁺ ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), by contacting the at least one further contain an optionally cation is selected from the group consisting of cesium ions (Cs ⁺⁾ and ammonium ion (NH 4 ^_+), for example, on the surface of the crystal of fluoride, It contains at least one element selected from the group consisting of Group 4 elements and Group 14 elements contained in the second complex ion and at least potassium ion (K ⁺ ), and contains lithium ion (Li ⁺ ) and sodium ion (Li +). Na ^+), rubidium ions ^(Rb +), cesium ion (Cs ⁺⁾ and ammonium ion _(NH ^{4 +)} fluoride containing and optionally further comprise at least one cation selected from the group consisting of crystalline Precipitates to give the desired fluoride phosphor.

The third step may be performed independently after the second step, and the third step is started after the start of the second step and before the end thereof, and the second step and the third step are performed. The steps of may be partially performed in parallel.

The fluoride phosphor particles obtained in the third step include the fluoride particles represented by the general formula (I), the second complex ion and at least potassium ion (K ⁺ ), and lithium ion (Li ⁺ ). sodium ion ^(Na +), rubidium ions ^(Rb +), cesium ion (Cs ⁺⁾ and ammonium ion _(NH ^{4 +)} at least one further contain an even contact good and a cation is a member selected from the group consisting of It is preferable that the surface region has a surface region in which the tetravalent manganese ion concentration is lower than the tetravalent manganese ion concentration in the internal region, and the surface region has a composition represented by the following general formula (II). .. In the formula, A, contains at least ^{K +, Li +, Na +} , Rb +, at least one further contain an optionally cations selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is , At least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <b.
A ₂ [M _1-a Mn ^{4 +} _a F ₆ ] (II)

a and b are not particularly limited as long as 0 <a <b is satisfied. The value of a can be appropriately selected according to the desired light emission characteristics, moisture resistance, and the like. Further, the value of a includes, for example, the second complex ion in the third step and at least potassium ion (K ⁺ ), and lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ). , it is controlled by adjusting the amount of contact to the crystal of cesium ions (Cs ⁺⁾ and ammonium ion (NH 4 ^₊₎ of at least one further comprise good cations also the fluoride is selected from the group consisting of it can.

In the third step, the fluoride crystals in the dispersion to which the reducing agent was added, the second complex ion and at least potassium ion (K ⁺ ) were contained, and lithium ion (Li ⁺ ) and sodium ion (Na ^{+) were contained.} ), rubidium ions (Rb ^+), a method of contacting the cesium ion (Cs ⁺⁾ and ammonium ion (NH 4 ^₊₎ may further comprise at least one member selected from the group consisting of cations is not particularly limited .. For example, a solution containing a reducing agent and at least potassium ion (K ⁺ ), including lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and is preferably a method of mixing at least one solution comprising a solution and a second complex ion containing good cations also include at least one selected from the group consisting of ammonium ion (NH 4 ^₊₎ A method of mixing the dispersion to which the reducing agent is added and at least one of the second solution and the third solution is more preferable, and the dispersion to which the reducing agent is added and the second solution are described. A method of mixing the solution and the third solution is more preferable. Here, the preferred embodiments of the second solution and the third solution are as described above.
In addition, it contains a dispersion and at least potassium ion (K ⁺ ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ) and ammonium ion (NH ₄ ^+). When mixing one of a solution containing a cation and a solution containing a second complex ion, which may further contain at least one selected from the group consisting of), the cation and the second complex ion are mixed. The other ion, which is not contained in the solution, may be contained in the dispersion at a content required for the third step.
The second solution and the third solution in the third step may have the same composition as or different from the second solution and the third solution in the first step.

The third step contains the reducing agent-added dispersion and at least potassium (K ⁺ ), lithium (Li ⁺ ), sodium (Na ⁺ ), rubidium (Rb ⁺ ), cesium (Cs ⁺ ) and ammonium. If that comprises mixing at least one solution comprising a solution and a second complex ion containing (NH 4 ^₊₎ further contain an optionally cation at least one member selected from the group consisting of, mixing means Depending on the reaction vessel and the like, it can be appropriately selected from the commonly used mixing means.
The temperature in the third step is not particularly limited. For example, it can be carried out in a temperature range of 15 to 40 ° C., preferably in a temperature range of 23 to 28 ° C.
Further, the atmosphere in the third step is not particularly limited. It may be carried out in a normal atmosphere or in an atmosphere of an inert gas such as nitrogen gas.
Further, the reaction time in the third step is not particularly limited. For example, 1 to 60 minutes, more preferably 5 to 30 minutes.

The third step contains the reducing agent-added dispersion and at least potassium ion (K ⁺ ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), rubidium ion (Rb ⁺ ), cesium ion ( cs ⁺⁾ and mixing the at least one solution comprising a solution and a second complex ion containing good cations also include at least one selected from the group consisting of ammonium ion (NH 4 ^₊₎ When it is contained, the amount of the solution containing the second complex ion and the solution containing the cation to the fluoride particles in the dispersion to which the reducing agent is added is determined by the light emission characteristics and moisture resistance of the target fluoride phosphor. It can be appropriately selected according to the above. For example, the amount of the second complex ion added to the fluoride particles can be 1 mol% to 40 mol%, preferably 5 mol% to 30 mol%.

Fluoride phosphor particles having a chemical composition represented by the general formula (I) and having a surface region having a tetravalent manganese ion concentration lower than the tetravalent manganese ion concentration in the internal region form a core portion. After the first step, the surface region may be formed by a method including the second'step different from the second step and the third step.

(Second step)
In the second step, the fluoride crystals obtained in the first step are put into an aqueous solution containing alkaline earth metal ions and a reducing agent. When the fluoride crystals are put into an aqueous solution containing alkaline earth metal ions, a dissolution reaction of the fluoride crystals occurs, and metal ions and fluorine ions constituting the fluoride crystals are generated. Here, the fluorine ions react with the alkaline earth metal ions to form alkaline earth metal fluoride on the surface of the fluoride crystals, and the tetravalent manganese is higher than the tetravalent manganese ion concentration in the internal region. A surface region having a low ion concentration can be formed.
The alkaline earth metal fluoride contained in the surface region of the fluoride phosphor particles can suppress a further dissolution reaction of the fluoride phosphor. Further, since the tetravalent manganese ion is reduced to the divalent manganese ion by the presence of the reducing agent, the production of manganese dioxide is suppressed.
The fluoride phosphor obtained through the second step contains alkaline earth metal fluoride in its surface region, and the presence of a reducing agent suppresses the production of manganese dioxide on the surface. Therefore, it is considered that the emission intensity is high and the decrease in emission output and the chromaticity shift are suppressed over a long period of time. It is considered that excellent long-term reliability can be achieved by this.

A solution containing alkaline earth metal ions contains at least alkaline earth metal ions, counterions and water. Examples of the alkaline earth metal ion include magnesium ion (Mg ²⁺ ), calcium ion (Ca ²⁺ ), and strontium ion (Sr ²⁺ ).
Above all, it is preferable that the alkaline earth metal ion contains calcium ion from the viewpoint of suppressing chromaticity shift and decrease in light emission output and moisture resistance.

The solution containing alkaline earth metal ions is obtained as an aqueous solution of a compound containing alkaline earth metals, and may contain other components (for example, alcohols such as methanol and ethanol) as necessary. Compounds containing alkaline earth metals include, for example, nitrates of alkaline earth metals (eg, Mg (NO ₃ ) ₂ , Ca (NO ₃ ) ₂ , Sr (NO ₃ ) ₂ ), acetates (eg, Mg (CH)). ₃ CO ₂ ) ₂ , Ca (CH ₃ CO ₂ ) ₂ , Sr (CH ₃ CO ₂ ) ₂ ), chloride (eg MgCl ₂ , CaCl ₂ , SrCl ₂ ), iodide (eg MgI ₂ , CaI ₂₎ , _SrI 2), and bromide _{(e.g., MgBr 2, CaBr 2, SrBr} 2) and the like.
As the compound containing an alkaline earth metal, one type may be used alone or two or more types may be used in combination.

The concentration of alkaline earth metal ions in a solution containing alkaline earth metal ions is not particularly limited. The lower limit of the concentration of alkaline earth metal ions in the solution containing alkaline earth metal ions is, for example, 0.01% by mass or more, preferably 0.03% by mass or more, and more preferably 0.05% by mass or more. is there. The upper limit of the concentration of alkaline earth metal ions in the solution containing alkaline earth metal ions is, for example, 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less.

The solution containing alkaline earth metal ions is preferably 100 to 3000 parts by mass, more preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the fluoride crystals. Moisture resistance is further improved by the amount of such a solution containing alkaline earth metal ions.

Due to the presence of the reducing agent, at least a part of the tetravalent manganese ions generated by the reaction with the solution containing fluoride crystals and alkaline earth metal ions is reduced to divalent manganese ions. Specifically, the addition of the reducing agent preferably reduces 90 mol% or more of the tetravalent manganese ions generated by the reaction with the solution containing fluoride crystals and alkaline earth metal ions, preferably 95 mol%. It is more preferable that the above is reduced.

The reducing agent is not particularly limited as long as it can reduce tetravalent manganese ions. Specific examples of the reducing agent include hydrogen peroxide and oxalic acid. Of these, hydrogen peroxide can reduce manganese without adversely affecting the matrix of fluoride crystals, such as dissolving fluoride crystals, and is finally decomposed into harmless water and oxygen. It is preferable because it is easy to use in the manufacturing process and has a small environmental load.

The amount of the reducing agent added is not particularly limited. The amount of the reducing agent added can be appropriately selected depending on, for example, the content of manganese contained in the fluoride crystals, but the amount added may not adversely affect the matrix of the fluoride crystals. preferable. Specifically, the amount of the reducing agent added is preferably 1 equivalent% or more, and more preferably 3 equivalent% or more, based on the content of manganese contained in the fluoride crystals.

Here, 1 equivalent means the number of moles of the reducing agent required to reduce 1 mol of tetravalent manganese ions to divalent manganese ions.

The lower limit of the concentration of the reducing agent is, for example, 0.01% by mass or more, preferably 0.03% by mass or more, and more preferably 0.05% by mass with respect to the solution containing alkaline earth metal ions. That is all. The upper limit of the concentration of the reducing agent is, for example, 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less with respect to the solution containing alkaline earth metal ions.

Contact method The method of contacting the fluoride particles with the solution containing alkaline earth metal ions in the presence of a reducing agent is not particularly limited. For example, a method of mixing a solution containing a reducing agent, fluoride particles and alkaline earth metal ions can be mentioned.

Contact time Further, in the presence of the reducing agent, the contact time between the fluoride crystal and the solution containing the alkaline earth metal ion is the time during which the alkaline earth metal fluoride is formed on the surface of the fluoride crystal. There is no particular limitation. For example, it can be 10 minutes to 10 hours, preferably 30 minutes to 5 hours.

Reaction temperature The temperature at which the solution containing the reducing agent, fluoride crystals and alkaline earth metal ions is mixed is not particularly limited. For example, mixing can be carried out in a temperature range of 15 to 40 ° C., preferably in a temperature range of 23 to 28 ° C.
Further, the atmosphere at the time of mixing is not particularly limited. The mixing may be carried out in a normal atmosphere, or may be carried out in an atmosphere of an inert gas such as nitrogen gas.

[Other processes]
The method for producing a fluoride phosphor may further include other steps, if necessary. For example, the fluoride phosphor crystals produced in the third step can be recovered by solid-liquid separation by filtration or the like. Further, the fluoride phosphor crystals may be washed with a solvent such as ethanol, isopropyl alcohol, water and acetone. Further drying treatment may be performed, in which case, for example, at 50 ° C. or higher, preferably 55 ° C. or higher, more preferably 60 ° C. or higher, and for example, 110 ° C. or lower, preferably 100 ° C. or lower, more preferably 90 ° C. or lower. dry. The drying time is not particularly limited as long as the water adhering to the fluoride phosphor crystals can be evaporated, and is, for example, about 10 hours.

(Other phosphors)
The light emitting device preferably further contains another phosphor in addition to the fluoride phosphor. The other phosphor may be one that absorbs the light from the light source and converts the wavelength into light having a different wavelength. Other phosphors can be contained in the sealing material in the same manner as the fluoride phosphor, for example, to form a light emitting device.
Examples of other phosphors include nitride-based phosphors mainly activated by lanthanoid-based elements such as Eu and Ce, oxynitride-based phosphors, and sialone-based phosphors; lanthanoid-based phosphors such as Eu and Mn. Alkaline earth halogen apatite phosphors, alkaline earth metal metalloid halogen phosphors, alkaline earth metal aluminate phosphors, alkaline earth silicates, alkaline earths, which are mainly activated by transition metal elements. Rare earth aluminates, rare earth silicates, and lanthanoid elements such as Eu, which are mainly activated by lanthanoid elements such as sulfide, alkaline earth thiogallate, alkaline earth silicon nitride, germanate; It is preferable that it is at least one selected from the group consisting of organics and organic complexes that are activated in.
Specifically, as other phosphors, for example, (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) ₂ : Eu and the like can be mentioned.
By including other phosphors, it is possible to provide a light emitting device having various color tones.
When the light emitting device further contains other phosphors, the content thereof is not particularly limited and may be appropriately adjusted so as to obtain desired light emitting characteristics.

When the light emitting device further contains other phosphors, it preferably contains a phosphor that emits green to yellow, and absorbs light in the wavelength range of 380 nm to 485 nm. It is more preferable to include a phosphor that emits green to yellow having an emission peak wavelength in the range of 495 nm to 590 nm. When the light emitting device contains a phosphor that emits light from green to yellow, it can be more preferably applied to a liquid crystal display device.

The phosphor that emits light from green to yellow has a composition formula of (Si, Al) ₆ (O, N) ₈ : β-sialon represented by Eu, and a composition formula of SrGa ₂ S ₄ : thiogallate represented by Eu. Composition formula is (Ca, Sr, Ba, Zn) ₈ MgSi ₄ O ₁₆ (F, Cl, Br, I) ₂ : Halosilicate represented by Eu, or composition formula is (Y, Lu) ₃ (Al, Ga) ₅ O ₁₂ : It is preferable that the fluorophore is at least one selected from the group consisting of the rare earth aluminate fluorophore represented by Ce. As the phosphor that emits light from green to yellow, one type may be used alone, or two or more types may be used in combination.

(Content of phosphor in sealing material)
The content of the fluorescent substance in the sealing material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder. The phosphor is more preferably 20 to 180 parts by mass, further preferably 30 to 120 parts by mass, particularly preferably 40 to 100 parts by mass, and most preferably 40 parts by mass with respect to 100 parts by mass of the binder. ~ 80 parts by mass. When the content of the phosphor of the sealing material is within the above range, the light emitting element can be sufficiently coated, the light emitted from the light emitting element can be efficiently wavelength-converted by the phosphor, and the light is emitted efficiently. be able to. Further, when the content of the phosphor in the sealing material is 10 to 200 parts by mass with respect to 100 parts by mass of the binder, the phosphors 7 and 8 that coat the light emitting element 4 with a uniform thickness are provided. A first portion 9 including the first portion 9 and a second portion 10 having a thickness of 1/10 or more of the total thickness of the sealing member can be formed immediately above the light emitting element 4.

(Content of phosphor in the first part)
The content of the phosphor in the first site is preferably 20 to 400 parts by mass, more preferably 25 to 380 parts by mass, and further preferably 30 to 30 parts by mass with respect to 100 parts by mass of the binder in the first site. It is 350 parts by mass, particularly preferably 35 to 300 parts by mass. When the content of the phosphor contained in the first portion is within the above range, the light emitting element can be coated with the phosphor having a uniform thickness, and the light from the light emitting element is efficiently wavelength-converted by the phosphor. can do.

(Mass ratio of phosphor that emits green to yellow and red phosphor)
When the phosphor contains a red phosphor (ie, a fluoride phosphor) and a phosphor that emits green to yellow, the mass ratio of the fluorescent that emits green to yellow to the red phosphor (fluorescence that emits from green to yellow). The body: red fluorophore) is preferably 5:95 to 95: 5, more preferably 10:90 to 90:10, even more preferably 20:80 to 80:20, and particularly preferably 30:70 to 70:30. Is. When the phosphor contains a red fluorescent substance and a phosphor that emits green to yellow light in the above range, the red fluorescent substance contains a fluoride having a chemical composition represented by the general formula (I), and therefore red fluorescence. The half-value width of the body's emission spectrum is narrow, the gap between the peak of the emission spectrum that emits green to yellow is large, the light from the light emitting element is absorbed, and the color reproduction range is wide and high-brightness light is emitted. it can.

(Filler)
The sealing material may contain a filler. The filler is preferably an inorganic filler. Examples of the inorganic filler include titanium oxide, zinc oxide, alumina, silica, zirconia, barium titanate, calcium phosphate, calcium carbonate, white carbon, talc, magnesium carbonate, boron nitride, glass fiber and the like. Of these, the filler is preferably alumina, silica, or zirconia. The shape of the filler may be spherical, scaly, or multi-shaped by crushing a lump, but a spherical shape is preferable. The filler preferably has a volume average particle size (median diameter: d50) of 1 μm to 100 μm measured by a laser diffraction / scattering type particle size distribution meter. The filler has a volume average particle size (median diameter: d50) measured by a laser diffraction / scattering type particle size distribution meter, more preferably 2 μm to 80 μm, further preferably 2 μm to 60 μm, and particularly preferably 2 to 50 μm. is there.

The content of the filler of the sealing material is not particularly limited. The content of the filler in the sealing material is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, still more preferably 3 to 20 parts by mass, and particularly, with respect to 100 parts by mass of the binder. It is preferably 5 to 15 parts by mass. Dispersibility is improved by containing 5 to 15 parts by mass of a filler with respect to 100 parts by mass of the binder. For example, when a red fluorescent substance and a fluorescent substance that emits green to yellow light are contained, the seal is sealed. The red phosphor and the phosphor that emits green to yellow can be uniformly dispersed in the stop material. When the sealing material contains a filler, the phosphor can be deposited by centrifugal sedimentation so as to uniformly cover the light emitting element with the phosphor to form the first site. By coating the light emitting element at the first site with the phosphor that emits green to yellow and the red phosphor uniformly dispersed, the color shift is improved, the phosphor is efficiently excited, and visible light is effective. It can be utilized.
The filler may be contained in the first site together with the phosphor, or may be contained in the second site.

(Nanofiller)
The pre-cured sealing material constituting the sealing member may contain nanofillers. The nanofiller has a volume average particle size (median diameter: d50) of secondary particles measured by a laser diffraction / scattering type particle size distribution meter of 5 nm to 1000 nm, preferably 10 nm to 200 nm, more preferably 20 nm to 180 nm, and even more preferably. The nanofiller is preferably 30 nm to 150 nm, particularly preferably 40 nm to 120 nm, and most preferably 50 nm to 100 nm.
As the material of the nanofiller, for example, at least one kind of inorganic material selected from the group of inorganic oxides, metal nitrides, metal carbides, carbon compounds and sulfides can be used. Examples of the inorganic oxide include titanium oxide, tantalum oxide, niobium oxide, tungsten oxide, zirconium oxide, zinc oxide, indium oxide, tin oxide, hafnium oxide, yttrium oxide, silicon oxide, aluminum oxide and the like. Moreover, these composite inorganic oxides can be used. Examples of the metal nitride include silicon nitride and the like. Examples of the metal carbide include silicon carbide and the like. Examples of the carbon compound include a simple substance of carbon, but an inorganic material having translucency such as diamond or diamond-like carbon. Examples of the sulfide include copper sulfide, tin sulfide and the like. Above all, the material of the nanofiller is preferably silicon oxide.
The nanofiller may be contained in the first site together with the phosphor, or may be contained in the second site.

The content of the nanofiller in the sealing material is not particularly limited. The content of the nanofiller in the encapsulating material is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 4.0 parts by mass, still more preferably, with respect to 100 parts by mass of the binder. It is 0.3 to 3.0 parts by mass, particularly preferably 0.4 to 2.0 parts by mass. By including 0.1 to 5.0 parts by mass of the nanofiller with respect to 100 parts by mass of the binder, the nanofiller is arranged around the phosphor.
In the conventional ^{fluoride phosphor activated with Mn 4+} , on the particle surface, the tetravalent manganese ions constituting the fluoride phosphor react with the moisture in the air to generate manganese dioxide, and the particle surface is formed. As a result of being colored black, the brightness may decrease.
When the encapsulating material contains nanofiller, the nanofiller ^{adheres around the fluoride phosphor activated with Mn 4+} , and the reaction between tetravalent manganese ions and water can be further suppressed. It is considered that the formation of manganese dioxide can prevent the particle surface from being colored black. Therefore, the light emitting device of this embodiment can further suppress the decrease in light emitting output and the chromaticity deviation, and can achieve better durability in a long-term reliability test.

When the sealing material contains nanofiller, the phosphor, and if necessary, the filler and nanofiller can be more evenly dispersed in the binder, and the sealing member becomes a sealing member in the recess of the package. Before and during injection of the stop material, a fluorescent material, and if necessary, filler and nanofiller can be injected into the recesses of each package in an almost equal amount, so that a light emitting device having no variation in color tone in each package can be provided. Can be formed.

(Other materials)
The pre-curing sealing material constituting the sealing member contains at least a binder and a phosphor, and if necessary, in addition to the filler and nanofiller, if the binder is a resin, a resin. It may contain a curing agent or the like that cures the resin. Further, the sealing material may contain a dye, a pigment or the like. A void for diffusing light may be included to some extent so as not to adversely affect the reliability of the sealing member.

(Manufacturing method of sealing material)
The method for producing the sealing material is not particularly limited, and the mixing order of the materials and the like is not particularly limited.
Examples of the method for producing the sealing material include a method of simultaneously mixing a predetermined amount of each material, a method of sequentially mixing a predetermined amount of each material, and the like. The encapsulating material is preferably produced by putting a phosphor, a filler if necessary, a nanofiller if necessary, a binder, and other materials into a container in this order and stirring them.

[Manufacturing method of light emitting device]
The method for manufacturing the light emitting device of this embodiment includes a step of preparing a package having a side wall forming a recess, a step of arranging a light emitting element on the bottom surface of the recess, and a chemical composition represented by the following general formula (I). Then, a sealing material containing a fluoride phosphor particle having a surface region in which the tetravalent manganese ion concentration is lower than the tetravalent manganese ion concentration in the inner region of the phosphor particle and a binder is placed in the recess of the package. The light emitting element is coated with the sealing material injected into the recesses of the package after the steps of injecting the fluorofluorescent particles into the recesses and the fluoride phosphor particles are centrifugally settled on the bottom surface side of the recesses. A step of forming a pre-curing sealing member including a first site containing the first site and a second site arranged on the first site and substantially free of fluoride phosphor particles, and the sealing. It is a method of manufacturing a light emitting device including a step of curing a material and forming a sealing member.
A ₂ [M _1-b Mn ⁴⁺ _b F ₆ ] (I)
In the formula, A comprises at least ^{K +, Li +, Na +} , Rb +, a further contain an optionally cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} M is a It is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and b satisfies 0 <b <0.2.
Hereinafter, a method of manufacturing a light emitting device will be described with reference to FIG.

(Package preparation process)
A package 3 having a side wall forming the recess 2 is prepared. In the package 3, the first reed 5 and the second reed 6 are integrally molded on the bottom surface of the recess 2.

(Arrangement process of light emitting element)
The light emitting element 4 is arranged on the first reed 5 forming the bottom surface of the recess of the package 3 and bonded by die bonding. The positive and negative electrodes (not shown) of the light emitting element 4 are connected to the first reed 5 and the second reed 6 by wires 11 and 12, respectively. Further, in the method for manufacturing the light emitting device of the present embodiment, if necessary, the light emitting element 4, the first lead 5, the second lead 6, and the wires 11 and 12 are covered with an insulating member (not shown). It may be included. As the insulating member, it is preferable to form a film (layer) made of an inorganic compound on the first reed 5 and the second reed 6 (conductive member), the wires 11 and 12, and the light emitting element 4 by sputtering or vapor deposition. Further, it is more preferable that the insulating member forms a film (layer) by an atomic layer deposition method (Atomic Layer Deposition).

(Injection process of sealing material)
Next, a sealing material containing at least resin and phosphors 7 and 8 is injected into the recess 2 of the package 3, and the recess 2 is filled with the sealing material. It is preferable that the sealing material is injected into a plurality of recesses 2 of a plurality of arranged packages 3 with a syringe or the like. The encapsulating material may optionally include fillers, nanofillers or other materials.

(Centrifugal sedimentation of phosphor)
The package 3 in which the recess 2 is filled with the sealing material applies a forced centrifugal force so that the fluoride phosphor particles 7 and the other phosphor particles 8 in the sealing material are coated on the light emitting element 4. After centrifugal sedimentation, the light emitting element is coated with a sealing material and is arranged on the first site 9 containing the phosphor particles and the first site 9, and is substantially free of the fluorescent particles. A sealing member including the two parts 10 is formed. It is preferable that the package 3 in which the recess 2 is filled with the sealing material is placed in a magazine and rotated by a centrifuge until it is sufficiently settled to centrifuge the phosphor particles.

Centrifugal sedimentation of the phosphor particles is performed by matching the direction of the resultant force of the centrifugal force and gravity with the direction perpendicular to the bottom surface of the package in which the light emitting element is arranged. Here, the bottom surface of the package includes a first lead 5 on which a light emitting element is placed and a second lead 6. Centrifugal sedimentation of the phosphor particles causes the phosphor particles dispersed in the encapsulating material to emit light by matching the direction of the resultant force of centrifugal force and gravity with the vertical direction of the bottom surface of the package in which the light emitting element is arranged. It is possible to settle on the element and on the bottom surface of the package with a uniform thickness to form a first portion 9 having a uniform thickness.

Centrifugal sedimentation of the phosphor is preferably performed so that the thickness of the second portion 10 immediately above the light emitting element 4 is 1/10 or more of the thickness of the entire encapsulating material. The thickness of the second portion 10 can be adjusted by appropriately adjusting the conditions of centrifugal sedimentation, the type and amount of the binder in the sealing material, and the type and amount of the phosphor particles. By setting the conditions and centrifuging the phosphor particles, the phosphor particles can be centrifugally settled so that the thickness of the second portion is 1/10 or more of the thickness of the entire encapsulating material.

Centrifugal sedimentation of the phosphor particles is further preferably performed so that the thickness of the second portion 10 is one-fourth or more of the thickness of the entire encapsulating material immediately above the light emitting element 4. The thickness of the second portion 10 can be adjusted by appropriately adjusting the conditions of centrifugal sedimentation, the type and amount of the binder in the sealing material, and the type and amount of the phosphor particles. By setting the conditions and centrifuging the phosphor particles, the phosphor particles can be centrifugally settled so that the thickness of the second portion is one-fourth or more of the thickness of the entire encapsulating material.

(Curing process of sealing material)
Then, after the phosphor particles are centrifugally settled, the binder is cured, and the first portion containing the phosphor and covering the light emitting element with the sealing material injected into the recess 2 of the package 3 and the first portion thereof. It is possible to obtain a light emitting device which is arranged on one site and has a sealing member formed of a sealing member including a second site which is substantially free of phosphor particles. The curing method of the binder is not particularly limited, and the curing method can be appropriately selected depending on the type of the binder.

<Image display device>
The image display device includes at least one of the light emitting devices. The image display device is not particularly limited as long as it includes a light emitting device, and can be appropriately selected from conventionally known image display devices. The image display device is configured to include, for example, a color filter member, a light transmission control member, and the like in addition to the light emitting device.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

(Production Example 1 of Fluoride Fluorescent Substance)
_{21.66 g of K 2} MnF ₆ is weighed so as to have the charged composition ratio shown in Table 1, dissolved in 800 g of 55 mass% HF aqueous solution, and then 400 g of _{40 mass% H 2} SiF _{6 aqueous solution is added to solution A.} Was prepared. On the other hand, _{260.14 g of KHF 2} was weighed and dissolved in 450 g of a 55 mass% HF aqueous solution to prepare a solution B. Also, it was obtained by weighing 40 wt% of _H 2 SiF ₆ aqueous solution 200g and solution C.
Next, at room temperature (23 to 28 ° C.), the phosphor crystals (fluoride particles) are precipitated by simultaneously dropping the solution B and the solution C while stirring the solution A, as shown in Table 2. When the dropping of 75% by weight of each of the solution B and the solution C was completed, the dropping was temporarily stopped (first step).
_{After adding a 30 mass% H 2} O ₂ aqueous solution weighing 15 g as a reducing agent to the solution A (second step), the dropping of the solution B and the solution C was restarted (the third step). After the dropping of the solution B and the solution C is completed, the obtained precipitate is separated, washed with IPA (isopropyl alcohol), and dried at 70 ° C. for 10 hours to obtain the fluoride phosphor (K ₂ [Si) of Production Example 1. _0.97 Mn ^{4 +} _0.03 F ₆ ]) was prepared.

(Example 1)
(Manufacturing of sealing material)
As the red phosphor, the fluoride phosphor of Production Example 1 was used. As a phosphor that emits light from green to yellow, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon) was used. The mass ratio of the phosphor that emits green to yellow and the red phosphor is the mass ratio of the phosphor that emits green to yellow and the red phosphor (fluorescent that emits green to yellow: red phosphor), which is 27:73. Formulated as follows. The binder was a resin, and the resin used was phenylsilicone (Dow Corning (registered trademark OE-6630). The filler was a volume average measured by a laser diffraction / scattering particle size distribution meter (MASTER SIZEr 2000 manufactured by MALVERN). A silica having a particle size (median diameter: d50) of 11 μm was used. The nanofiller was a volume average grain (median diameter: median diameter: of secondary particles) of secondary particles measured with a laser diffraction scattering type particle size distribution meter (MASTER, SIDER 2000 manufactured by MALLVERN). Silicon oxide (AEROSIL®) having a d50) of 12 nm was used. The composition of each component is as follows. The resin content in 100% by mass of the sealing material is 91.1% by mass. Is.
A fluorescent substance (red fluorescent substance and a fluorescent substance that emits green to yellow light) is put into a stirring container, then a filler and a nanofiller are put in, and finally a resin and a curing agent are put in, and the mixture is stirred for about 5 minutes. The sealing material 1 was obtained.

(Encapsulating material)
Binder (silicone resin main agent) 100 parts by mass Red phosphor (Production Example 1) 31.57 parts by mass (43.25 parts by mass x 0.73)
Fluorescent material (β-sialon) that emits light from green to yellow 11.68 parts by mass (43.25 parts by mass x 0.27)
Filler (silicon oxide) 5 parts by mass Nanofiller (silicon oxide: SiO ₂ ) 0.4 parts by mass Hardener (liquid silicone resin) 400 parts by mass

(Manufacturing method of light emitting device)
A package having a side wall forming a recess was prepared, a light emitting element was placed in the recess, and then the sealing material 1 was injected into the recess of the package using a syringe. A light emitting device having an emission peak wavelength in the range of 380 nm to 485 nm was used.
Next, the package 3 in which the concave portion 2 is filled with the sealing material is placed in a magazine and sufficiently rotated by a centrifuge to centrifuge the phosphor, and then the fluorescent material is injected into the concave portion of the package. A first portion covering the light emitting element and a second portion arranged on the first portion thereof and substantially free of the phosphor were formed. The thickness of the second portion before curing was one-fourth or more of the total thickness of the sealing material immediately above the light emitting element. Specifically, immediately above the light emitting element, the thickness of the sealing member was 410 μm, the thickness of the first portion was 150 μm, and the thickness of the second portion was 260 μm.
In the step of centrifuging the phosphor, the direction of the resultant force of the centrifugal force and the gravity was made to coincide with the vertical direction of the bottom surface of the package in which the light emitting element is arranged, and the phosphor was centrifuged.
The encapsulant is then cured to include a first site that contains the phosphor and coats the light emitting device, and a second site that is located on the first site and is substantially free of the phosphor. A stop member was formed to obtain a light emitting device of Example 1.

FIG. 2 is a 20-fold photograph of the cross section of the light emitting device of Example 1 taken with a fluorescence microscope. As shown in FIG. 2, the light emitting device 1 of the first embodiment includes a phosphor and is arranged on a first portion 9 and a first portion 9 that includes a phosphor and covers the light emitting element 4, and substantially disperses the phosphor. It was confirmed that the second site 10 not included was formed.

(Comparative Example 1)
In the same manner as in Example 1, except that the sealing member containing the first portion and the second portion was not formed without centrifuging the phosphor in the encapsulating material in Example 1. A light emitting device of Comparative Example 1 was obtained. In the light emitting device of Comparative Example 1, the phosphor was substantially uniformly dispersed in the sealing member.

(PCT (Pressure Cooker Test))
The light emitting device according to Example 1 and Comparative Example 1 was subjected to a pressure cooker test (PCT) at 121 ° C., 100% humidity, and 2 atm (atm). The results are shown in FIG.

As shown in FIG. 3A, in Example 1 of the present disclosure, no discoloration could be confirmed on the surface of the light emitting device even after the lapse of 200 hours of PCT.
On the other hand, as shown in FIG. 3B, in Comparative Example 1, discoloration was confirmed on the surface of the light emitting device in 4 hours of PCT. As shown in FIG. 3 (c), in Comparative Example 1, the discoloration of the surface of the light emitting device further progressed in 100 hours of PCT, and as shown in FIG. 3 (d), Comparative Example 1 showed the surface of the light emitting device in 200 hours of PCT. The discoloration of was further advanced. It is considered that when such discoloration occurs, light is absorbed at the discolored portion, causing color shift of the light emitting device and reduction of light output.
From the results shown in FIG. 3, it can be seen that the light emitting device of the first embodiment of the present disclosure is excellent in durability.

(Examples 2 to 4, Comparative Examples 2 to 4 and Reference Example)
A light emitting device was manufactured in the same manner as in Example 1 except that the red phosphor shown in Table 3 and the phosphor that emits light from green to yellow were used. Further, in the reference example, YAG was used as the phosphor as the light emitting device. The light emitting devices of Reference Examples, Examples 2 to 4 and Comparative Examples 2 to 4 all contain a phosphor, and are arranged on a first portion covering the light emitting element and the first portion of the phosphor. It has a sealing member having a second portion that is substantially free of inclusion.

(Compared to NTSC)
The light emitting devices of Reference Examples, Examples 2 to 4 and Comparative Examples 2 to 4 were incorporated into the image display device. The NTSC ratio of these image display devices was measured.
The NTSC ratio is the three primary colors of the standard method, red (0.670, 0.), defined by the National Television Standards Committee in terms of the chromaticity (x, y) of the CIE 1931 XYZ color system. 330), green (0.210, 0.710), blue (0.140, 0.080) with reference to the triangle obtained by connecting the chromaticity of the single colors of red, green, and blue of the image display device. It is the area ratio comparing. This area ratio is defined as a color reproduction range, and it is determined that the higher the ratio, the higher the color reproducibility.
The image display device preferably has a color reproduction range of 70% or more of NTSC on the CIE1931 chromaticity diagram.

(SRGB)
The light emitting devices of Reference Examples, Examples 2 to 4 and Comparative Examples 2 to 4 were incorporated into the image display device. The sRGB of these image display devices was measured.
The sRGB ratio is the three primary colors of the standard method, red (0.640, 0.330), defined by the chromaticity (x, y) of the CIE 1931 XYZ color system by the International Electrical Communication. Based on the triangle connecting green (0.300, 0.600) and blue (0.150, 0.060), the triangles obtained by connecting the chromaticity of red, green, and blue of the image display device were compared. It is the area ratio. This area ratio is defined as a color reproduction range, and it is determined that the higher the ratio, the higher the color reproducibility.

(Relative luminous flux: Relative Flux (LED))
For the light emitting devices of Reference Examples, Examples 2 to 4 and Comparative Examples 2 to 4, the luminous flux was measured using an integrating sphere, and the relative luminous flux was calculated with reference to the luminous flux of the reference example.

Table 3 shows the measurement results of the NTSC ratio, sRGB, and relative luminous flux (LED) of the light emitting devices of Reference Examples, Examples 2 to 4, and Comparative Examples 2 to 4. The numerical values shown in parentheses in the phosphors in Table 3 indicate the peak top wavelength (emission peak wavelength) in the emission spectrum of each phosphor.

As shown in Table 3, the light emitting devices of Examples 2 to 4 using the phosphor of Production Example 1 are compared with the light emitting devices of Comparative Examples 2 to 4 using a phosphor other than the phosphor of Production Example 1. The NTSC ratio, sRGB, and relative luminous flux (LED) all showed excellent values, and the color reproducibility and relative luminous flux (LED) were all improved. The relative luminous flux of the light emitting devices of Comparative Examples 2 to 4 was 58, 64, 68 with respect to the relative luminous flux of the light emitting device of the reference example, but the relative luminous flux of the light emitting devices of Comparative Examples 2 to 4 was reduced. The relative luminous flux of the light emitting device of Examples 2 to 4 was improved to 87, 82, 75.

The light emitting device according to the present disclosure suppresses a decrease in light emission output and a chromaticity shift, and in particular, a white lighting light source using a blue light emitting diode as a light source, a backlight light source, an LED display, a traffic light, an illuminated switch, various sensors, and a light emitting device. It can be used for various indicators, etc., and exhibits excellent durability and light emission characteristics, especially in lighting applications.

1: Light emitting device, 2: Concave, 3: Package, 4: Light emitting element, 5: First lead, 6: Second lead, 7: Fluorescent phosphor particles, 8: Fluorescence other than fluoride phosphor particles Body particles, 9: first part, 10: second part, 11, 12: wire

Claims (5)

A package with side walls forming a recess and
A light emitting element arranged at the bottom of the recess and
It is provided with a sealing member that covers the light emitting element and is arranged in the recess.
The sealing member has a first portion that covers the light emitting element and contains a phosphor, and a second portion that is arranged on the first portion and does not substantially contain the phosphor. ,
The sealing member contains a resin and has a phosphor content of 30 to 120 parts by mass with respect to 100 parts by mass of the resin.
The sealing member contains 1 to 30 parts by mass of a filler having a volume average particle diameter of 1 μm to 100 μm with respect to 100 parts by mass of the resin.
The light emitting element emits light having an emission peak wavelength in the range of 380 nm to 485 nm.
The phosphor has a composition represented by _{CaAlSiN 3} : Eu or (Ca, Sr) AlSiN _{3: Eu, and}
(Si, Al) ₆ (O, N) ₈ : A phosphor that emits green to yellow light containing β-sialon having a composition represented by Eu, and
Includes at least ^{K +, Li +, Na +} , Rb +, further and optionally containing an even cation at least one selected from Cs ⁺ and the group consisting of _NH ^{4 +,} and Si, and ^{Mn 4+,} and fluorine atom When the total number of moles of the cation is 2 mol, the number of moles of Mn ⁴⁺ exceeds 0 and is less than 0.2, and the sum of the number of moles of ^{Mn 4+ and Si is 1.} A light emitting device comprising a fluoride phosphor having a composition. The light emitting device according to claim 1, wherein the content of the phosphor in the first portion is 20 to 400 parts by mass with respect to 100 parts by mass of the resin contained in the first portion. The light emitting device according to claim 1 or 2, wherein the mass ratio of the phosphor that emits light from green to yellow to the fluoride phosphor is 5:95 to 95: 5. Further comprising a first reed and a second reed located at the bottom of the recess, at least the first reed and the second reed are covered with an insulating member containing an oxide or nitride. The light emitting device according to any one of claims 1 to 3. An image display device including at least one light emitting device according to any one of claims 1 to 4.

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