JP6024850B2 - Fluoride phosphor and light emitting device using the same - Google Patents

Description

  The present invention relates to a fluoride phosphor and a light emitting device using the same.

  A light emitting diode (LED) is a semiconductor light emitting element that is often used as a substitute for a conventional light source, and is useful as a display lamp, a warning lamp, a display lamp, and an illumination lamp. Various light emitting devices that emit light in white, light bulb color, orange color, and the like by combining a semiconductor light emitting element produced from a group III-V semiconductor such as gallium nitride (GaN) and a phosphor have been developed. The light emitting devices that emit white light and the like are adjusted in color tone by the principle of color mixing of light. As a method for emitting white light, a method using a light emitting element that emits ultraviolet light and three types of phosphors that emit red (R), green (G), and blue (B), and blue light emission. A method using a light emitting element that emits light and a phosphor that emits yellow or the like is well known. Light-emitting devices using a light-emitting element that emits blue light and a phosphor that emits yellow light or the like are required in a wide range of fields such as lighting, in-vehicle lighting, displays, and backlights for liquid crystals. Among these, as a phosphor used for display applications, in order to reproduce a wide range of colors on the chromaticity coordinates, it is required to have good color purity as well as luminous efficiency. Furthermore, the phosphor used for display is required to have compatibility with a filter, and a phosphor having a narrow emission peak half-value width is required.

For example, as a red light emitting phosphor having an excitation band in a blue region and having a narrow emission peak half-value width, K ₂ TiF ₆ : Mn ⁴⁺ , Ba ₂ TiF ₆ : Mn ⁴⁺ , Na ₂ TiF ₆ : Mn ⁴⁺ , K ₃ A fluoride phosphor activated by Mn ⁴⁺ having a composition such as ZrF ₇ : Mn ⁴⁺ is known (see, for example, Patent Document 1). A fluoride phosphor having a composition of K ₂ SiF ₆ : Mn ⁴⁺ is also known (see, for example, Patent Document 2). Furthermore, the excitation / emission spectrum and emission mechanism of a fluoride complex phosphor activated with Mn ⁴⁺ are also known (see, for example, Non-Patent Document 1).

Special table 2009-528429 gazette JP 2010-209111 A

A. G. Paulusz "Effective Mn (IV) Emission in Fluoride Coordination" J. Electrochemical Soc., 120 N7, 1973, p.942-947

The practical application of red-emitting Mn ^{4 +} -activated fluoride phosphors with a narrow emission peak half-width that is particularly suitable for display applications is desired. However, conventional products have sufficient emission characteristics in terms of emission intensity. Is not obtained.
In view of the above, an object of the present invention is to provide a red light emitting phosphor having excellent light emission intensity and a light emitting device using the same, in order to solve the conventional problems.

In order to solve the above-mentioned problems, the present inventors have intensively studied and as a result, the present invention has been completed. The present invention includes the following aspects.
A first aspect of the present invention is a fluoride phosphor having a chemical composition represented by the following general formula (I) and having a weight median diameter of 30 μm or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, M is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <0.2.)

The second aspect of the present invention is a fluoride phosphor having a chemical composition represented by the following general formula (I) and having a bulk density of 0.80 g / cm ³ or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, M is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <0.2.)

A third aspect of the present invention is a light emitting device including a light source that emits light in a wavelength range of 380 nm to 485 nm and the fluoride phosphor.
The 4th aspect of this invention is an image display apparatus provided with the said light-emitting device.

  According to a fifth aspect of the present invention, there is provided a first solution containing at least a first complex ion containing tetravalent manganese and hydrogen fluoride, a second solution containing at least a potassium ion and hydrogen fluoride, and a group 4 And a third solution containing at least one second element selected from the group consisting of an element and a group 14 element and a second complex ion containing fluorine ions. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the red light emission fluorescent substance which has the outstanding light emission intensity, and a light-emitting device using the same can be provided.

It is a schematic sectional drawing which shows an example of the light-emitting device which concerns on this embodiment. It is a schematic plan view which shows an example of the light-emitting device which concerns on this embodiment.

Hereinafter, the fluoride fluorescent substance, the manufacturing method thereof, and the light emitting device according to the present invention will be described with reference to embodiments and examples. However, the embodiment described below exemplifies a fluoride phosphor, a manufacturing method thereof, and a light-emitting device for embodying the technical idea of the present invention. The manufacturing method and the light emitting device are not specified as follows.
The relationship between the color name and the chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Specifically, 380 nm to 455 nm is blue purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red , 610 nm to 780 nm is red.

  In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. . Moreover, the numerical range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. Further, the content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.

<Fluoride phosphor>
The fluoride fluorescent substance of the present invention has a chemical composition represented by the following general formula (I), and has a weight median diameter of 30 μm or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, M is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <0.2.
A fluoride phosphor having a chemical composition represented by the general formula (I) and having a weight median diameter of 30 μm or more, a narrow half-value width of the emission peak, and excellent emission intensity (luminance). Can be configured. When the weight median diameter is less than 30 μm, sufficient light emission intensity tends to be not obtained.

The weight median diameter of the fluoride phosphor is 30 μm or more, but from the viewpoint of light emission intensity, it is preferably 35 μm or more, more preferably 40 μm, and even more preferably 50 μm. The upper limit of the weight median diameter of the fluoride phosphor is not particularly limited, and is preferably 100 μm or less, and preferably 80 μm or less from the viewpoint of workability and moldability when mixing the phosphor and the resin. More preferably, it is 70 μm or less. This is because when the light emitting device is manufactured, it is easy to mix the phosphor and the resin and to form the mixture. If the weight median diameter is too large, mixing of the phosphor and the resin and molding of the mixture may be difficult.
In the present invention, the “weight median diameter” is defined as follows. The weight median diameter is a value obtained from a weight-based particle size distribution curve obtained by measuring the particle size distribution by a laser diffraction / scattering method. Specifically, the phosphor is dispersed in an aqueous solution containing a dispersant, and the particle size range is set to 0.1 μm or more and 600 μm or less by a laser diffraction particle size distribution measuring apparatus (for example, MASTER SIZER 2000 manufactured by MALVERN). It is a value obtained by measuring the particle size distribution. Among these, a weight median diameter (Dm) is calculated | required as a particle size corresponding to 50% of weight accumulation from a small diameter side.

The particle size distribution of the fluoride phosphor is not particularly limited. The particle size distribution of the fluoride phosphor is preferably a single peak particle size distribution, more preferably a single peak particle size distribution with a narrow distribution width, from the viewpoints of emission intensity and durability.
The particle shape of the fluoride phosphor is, for example, preferably non-tabular, and more preferably rectangular.

The average particle diameter measured by the Fischer Sub-Sieve Sizer (FSSS) of the fluoride phosphor is not particularly limited. The average particle diameter of the fluoride phosphor by the Fischer method is preferably 20 μm or more, and more preferably 30 μm or more, from the viewpoint of light emission intensity and durability. The upper limit of the average particle diameter by the Fisher method is preferably 100 μm or less, and more preferably 80 μm or less.
The average particle diameter by the Fisher method is measured using, for example, Fisher Sub-Sieve Sizer Model 95 manufactured by Fisher Scientific.

The bulk density of the fluoride phosphor is not particularly limited. The bulk density of the fluoride phosphor is preferably 0.80 g / cm ³ or more, more preferably 0.90 g / cm ³ or more, from the viewpoints of emission intensity and durability, and 1.00 g / cm 3. More preferably, it is ³ or more. The bulk density of the fluoride phosphor is preferably 2.67 g / cm ³ or less.
The bulk density is measured by, for example, a normal measurement method using a graduated cylinder. Hereinafter, the bulk density will be specifically described. In general, the bulk density of a powder is determined by measuring the volume of a powder sample of a known weight placed in a graduated cylinder, or measuring the weight of a powder sample of a known volume placed in a container through a volume meter, or Obtained by using a dedicated measuring container. Among these, the method using a graduated cylinder is preferable because it is simple.
Hereinafter, a method using a graduated cylinder will be described. First, a sufficient amount of sample is prepared for measurement, and passed through a sieve as necessary. Next, the required amount of sample is placed in a dry, constant-volume graduated cylinder. Here, the upper surface of the sample is leveled as necessary. These operations are performed gently so as not to affect the physical properties of the sample. Then, the volume density is obtained by reading the volume to the minimum scale unit and calculating the weight of the sample per unit volume. This bulk density is preferably measured repeatedly, more preferably measured multiple times, and more preferably obtained as an arithmetic average value of the measured values.

From the viewpoint of emission intensity, the fluoride phosphor preferably has a weight median diameter of 30 μm or more and a bulk density of 0.80 g / cm ³ or more, a weight median diameter of 35 μm or more and a bulk density of 0.90 g / cm. more preferably ³ or more, more preferably has a weight median diameter of and the bulk density exceeded 40μm is 0.90 g / cm ³ or more, and bulk density exceeded 50μm weight median diameter 0.90 g / cm It is particularly preferable that the number is ³ or more.

Moreover, the fluoride fluorescent substance of the present invention has a chemical composition represented by the following general formula (I) and a bulk density of 0.80 g / cm ³ or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
In the formula, M is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <0.2.
The composition formula has the chemical composition represented by the general formula (I), and the bulk density is 0.80 g / cm ³ or more, so that the half-value width of the emission peak is narrow and the emission intensity (luminance) is excellent. A fluoride phosphor can be constructed. When the bulk density is less than 0.80 g / cm ³ , there is a tendency that sufficient light emission intensity cannot be obtained.

The composition of the fluoride phosphor is represented by the general formula (I). The fluoride phosphor is a phosphor activated by Mn ⁴⁺ and can absorb red light in the short wavelength region of visible light and emit red light. The excitation light that is light in the short wavelength region of visible light is preferably mainly light in the blue region. Specifically, the excitation light preferably has a main peak wavelength of the intensity spectrum in the range of 380 nm to 500 nm, more preferably in the range of 380 nm to 485 nm, and in the range of 400 nm to 485 nm. Is more preferable, and it is particularly preferable to exist in the range of 440 nm to 480 nm.
The emission wavelength of the fluoride phosphor is not particularly limited as long as it is longer than the excitation light and is red. The emission spectrum of the fluoride phosphor preferably has a peak wavelength in the range of 610 nm to 650 nm. The half width of the emission spectrum is preferably small, specifically 10 nm or less.

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

The fluoride phosphor has a chemical composition represented by the above general formula (I), but a part of potassium ions (K ⁺ ) is composed of Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ^+. It may be substituted with at least one cation selected from the group. That is, the fluoride fluorescent material may have a chemical composition represented by the following general formula (Ia).
A ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (Ia)
In the formula, A is a cation containing at least K ⁺ , and optionally containing at least one selected from the group consisting of Li ⁺ , Na ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ , and M is It is at least one selected from the group consisting of Group 4 elements and Group 14 elements, and a satisfies 0 <a <0.2.

  The fluoride phosphor can be used, for example, in a conventionally known light emitting device. Examples of conventionally known light emitting devices include lighting devices such as fluorescent lamps, display devices such as displays and radars, and backlights for liquid crystals. Among these, the fluoride fluorescent material is preferably used for a light emitting device for a display (preferably a liquid crystal display device).

<Method for producing fluoride phosphor>
The method for producing fluoride particles is not particularly limited. The fluoride particles include, for example, a first solution containing at least a first complex ion containing tetravalent manganese and hydrogen fluoride, a second solution containing at least a potassium ion and hydrogen fluoride, and a Group 4 element. And at least one selected from the group consisting of Group 14 elements and a third solution containing at least a second complex ion containing fluorine ions.
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 obtained with excellent productivity. Can be manufactured.

(First solution)
The first solution (hereinafter also referred to as “solution A”) contains at least a first complex ion containing tetravalent manganese and hydrogen fluoride, and may contain other components as necessary. The first solution is obtained, for example, as an aqueous solution of hydrofluoric acid containing a tetravalent manganese source. The manganese source is not particularly limited as long as it is a compound containing manganese. Specific examples of the manganese source that can constitute the first solution include K ₂ MnF ₆ , KMnO ₄ , and K ₂ MnCl ₆ . Above all, it is stable in hydrofluoric acid as a MnF ₆ complex ion while maintaining the oxidation number (tetravalent) that can be activated without containing chlorine, which tends to destabilize the crystal lattice. Therefore, K ₂ MnF ₆ is preferable. In addition, among the manganese sources, those containing potassium can also serve as the potassium source contained in the second solution.
Manganese sources constituting the first solution may be used alone or in combination of two or more.

The lower limit of the hydrogen fluoride concentration in the first solution is usually 30% by weight or more, preferably 35% by weight or more, more preferably 40% by weight or more. Moreover, the upper limit of the hydrogen fluoride concentration in the first solution is usually 70% by weight or less, preferably 65% by weight or less, more preferably 60% by weight or less. When the hydrogen fluoride concentration is 30% by weight or more, the stability of the manganese source (for example, K ₂ MnF ₆ ) constituting the first solution to hydrolysis is improved, and the tetravalent manganese concentration in the first solution is increased. Fluctuations are suppressed. As a result, the amount of manganese activation contained in the resulting fluoride phosphor can be easily controlled, and variations in the luminous efficiency of the fluoride phosphor tend to be suppressed. Further, when the hydrogen fluoride concentration is 70% by weight or less, a decrease in the boiling point of the first solution is suppressed, and generation of hydrogen fluoride gas is suppressed. Thereby, the hydrogen fluoride concentration in the first solution can be easily controlled, and the variation (variation) in the particle diameter of the obtained fluoride phosphor can be effectively suppressed.

  The concentration of the first complex ion in the first solution is not particularly limited. The lower limit of the first complex ion concentration in the first solution is usually 0.1% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight or more. The upper limit of the first complex ion concentration in the first solution is usually 5% by weight or less, preferably 3% by weight or less, more preferably 2% by weight or less.

(Second solution)
The second solution (hereinafter also referred to as “solution B”) contains at least potassium ions and hydrogen fluoride, and may contain other components as necessary. The second solution is obtained, for example, as an aqueous solution of hydrofluoric acid containing potassium ions. Specific examples of potassium sources containing potassium ions that can constitute the second solution include water-soluble potassium salts such as KF, KHF ₂ , KOH, KCl, KBr, KI, potassium acetate, and K ₂ CO _3. Can do. Among these, KHF ₂ is preferable because it can be dissolved without lowering the concentration of hydrogen fluoride in the solution, and the heat of dissolution is small and the safety is high.
The potassium source which comprises a 2nd solution may be used individually by 1 type, or may use 2 or more types together. Moreover, it is preferable that the potassium source which comprises a 2nd solution does not contain a tetravalent manganese source substantially.

The lower limit of the hydrogen fluoride concentration in the second solution is usually 30% by weight or more, preferably 35% by weight or more, more preferably 40% by weight or more. The upper limit of the hydrogen fluoride concentration in the second solution is usually 70% by weight or less, preferably 65% by weight or less, more preferably 60% by weight or less.
Further, the lower limit value of the potassium ion concentration in the second solution is usually 10% by weight or more, preferably 12.5% by weight or more, more preferably 15% by weight or more. The upper limit value of the potassium ion concentration in the second solution is usually 35% by weight or less, preferably 32.5% by weight or less, more preferably 30% by weight or less. When the potassium ion concentration is 15% by weight or more, the yield of the fluoride phosphor tends to be improved. Further, when the potassium ion concentration is 30% by weight or less, the particle diameter of the obtained fluoride phosphor tends to be larger.

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

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

  The lower limit of the second complex ion concentration in the third solution is usually 10% by weight or more, preferably 15% by weight or more, more preferably 20% by weight or more. The upper limit of the second complex ion concentration in the third solution is usually 60% by weight or less, preferably 55% by weight or less, more preferably 50% by weight or less.

The mixing method of the first solution, the second solution, and the third solution is not particularly limited, and the second solution and the third solution may be added and mixed while stirring the first solution, The first solution and the second solution may be added and mixed while stirring the third solution. Alternatively, the first solution, the second solution, and the third solution may be charged into a container and mixed with stirring.
Among them, the mixing method of the first solution, the second solution, and the third solution is the second solution while stirring the first solution from the viewpoint of efficiently obtaining a fluoride phosphor having a desired weight median diameter. And a method of adding and mixing the third solution.

By mixing the first solution, the second solution, and the third solution, the first complex ion, potassium ion, and the second complex ion react with each other at a predetermined ratio, and the target fluoride phosphor. Crystallized out. The precipitated crystals can be recovered by solid-liquid separation by filtration or the like. Moreover, you may wash | clean with solvents, such as ethanol, isopropyl alcohol, water, and acetone. Further, a drying treatment may be performed, and drying is usually performed at 50 ° C. or higher, preferably 55 ° C. or higher, more preferably 60 ° C. or higher, and usually 110 ° C. or lower, preferably 100 ° C. or lower, more preferably 90 ° C. or lower. The drying time is not particularly limited as long as the water adhering to the fluoride phosphor can be evaporated, and is, for example, about 10 hours.
When mixing the first solution, the second solution, and the third solution, there is a difference between the charged composition of the first to third solutions, which are the phosphor raw materials, and the composition of the obtained fluoride phosphor. In consideration of the above, 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 as a product becomes a target composition.

<Light emitting device>
The light emitting device of the present invention includes a light source that emits light in a wavelength range of 380 nm to 485 nm and the fluoride phosphor. The light emitting device may further include other components as necessary. When the light emitting device contains the fluoride fluorescent material, excellent light emission efficiency can be achieved.

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

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

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

(Other phosphors)
It is preferable that the light emitting device further includes another phosphor in addition to the fluoride phosphor. Other phosphors only need to absorb light from the light source and perform wavelength conversion to light of different wavelengths. Other phosphors can be included in a sealing resin in the same manner as the fluoride phosphor, for example, to constitute a light emitting device.
Examples of other phosphors include nitride phosphors, oxynitride phosphors, sialon phosphors mainly activated by lanthanoid elements such as Eu and Ce; lanthanoid phosphors such as Eu, and Mn. Alkaline earth halogen apatite phosphor, alkaline earth metal borate phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate, alkaline earth mainly activated by transition metal elements Sulfide, alkaline earth thiogallate, alkaline earth silicon nitride, germanate; rare earth aluminate, rare earth silicate mainly activated by lanthanoid elements such as Ce; and mainly lanthanoid elements such as Eu It is preferably at least one selected from the group consisting of organics and organic complexes activated by.
Specific examples of other phosphors include (Ca, Sr, Ba) ₂ SiO ₄ : Eu, (Y, Gd) ₃ (Ga, Al) ₅ O ₁₂ : Ce, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), SrGa ₂ S ₄ : Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaAlSiN ₃ : Eu, (Ca, Sr) AlSiN ₃ : Eu, Lu ₃ Al ₅ O ₁₂ : Ce, (Ca, Sr, Ba, Zn) ₈ MgSi ₄ O ₁₆ (F, Cl, Br, I) ₂ : Eu and the like.
By including other phosphors, light emitting devices of various colors can be provided.
When the light emitting device further includes other phosphors, the content is not particularly limited, and may be appropriately adjusted so as to obtain desired light emission characteristics.

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

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

Hereinafter, an example of a light emitting device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a light emitting device according to the present invention. FIG. 2 is a schematic plan view showing an example of the light emitting device according to the present invention. This light-emitting device is an example of a surface-mounted light-emitting device.
The light emitting device 100 includes a light emitting element 10 of a gallium nitride compound semiconductor that emits light on a short wavelength side of visible light (for example, 380 nm to 485 nm), and a molded body 40 on which the light emitting element 10 is mounted. The molded body 40 has a first lead 20 and a second lead 30 and is integrally formed of a thermoplastic resin or a thermosetting resin. The molded body 40 has a recess having a bottom surface and side surfaces, and the light emitting element 10 is placed on the bottom surface of the recess. The light emitting element 10 has a pair of positive and negative electrodes, and the pair of positive and negative electrodes are electrically connected to the first lead 20 and the second lead 30 via the wire 60. The light emitting element 10 is sealed with a sealing member 50. The sealing member 50 is preferably made of a thermosetting resin such as an epoxy resin, a silicone resin, an epoxy-modified silicone resin, or a modified silicone resin. The sealing member 50 contains a fluoride phosphor 70 that converts the wavelength of light from the light emitting element 10.

<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 includes, for example, a color filter member, a light transmission control member, and the like in addition to the light emitting device.
The image display device is excellent in luminance and color reproduction range by including the light emitting device.

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

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

(Examples 2 and 3)
Except for changing the charging composition ratio and the charging amount shown in Table 1, the fluoride phosphors of Example 2 and Example 3 were produced in the same manner as in Example 1.

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

  Table 2 shows the light emission luminance characteristics and the powder characteristics of each fluoride phosphor obtained as described above. The light emission luminance characteristics were measured under the conditions of the excitation wavelength of 460 nm as the reflection luminance. Among the powder characteristics, the weight median diameter (Dm) is measured using a laser diffraction particle size distribution measuring apparatus (MASTER SIZER 2000 manufactured by MALVERN), and is measured by the Fisher method. S.) was measured using a Fisher Sub-Sieve Sizer Model 95 (manufactured by Fisher Scientific), and the bulk density was measured using a graduated cylinder.

(Examples 4 to 7)
A light emitting device was fabricated using the fluoride phosphors (red phosphors) of Examples 2 and 3. A light emitting device was manufactured by sealing a semiconductor light emitting element having a main wavelength of 451 nm to 452 nm with a sealing material in which a fluoride fluorescent material and a green fluorescent material were dispersed in a silicone resin.
Table 3 shows combinations of phosphors in Examples 4 to 7 and characteristics of the light emitting device. The characteristics of the light emitting device were measured by a commonly used method.
In Table 3, β sialon is represented by the composition formula (Si, Al) ₆ (O, N) ₈ : Eu
The chlorosilicate is a green phosphor represented by
Composition formula (Ca, Sr, Ba, Zn) ₈ MgSi ₄ O ₁₆ (F, Cl, Br. I) ₂ : Eu
It is a green phosphor represented by.

  The fluoride fluorescent substance and the light emitting device using the same according to the present invention are extremely excellent in light emission characteristics using a blue light emitting diode as a light source, such as a fluorescent display tube, a display, a PDP, a CRT, a FL, a FED, and a projection tube. It can be used for light sources, LED displays, white illumination light sources, traffic lights, illumination switches, various sensors, various indicators, and the like, and exhibits excellent emission characteristics particularly in display applications.

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

Claims (13)

A fluoride phosphor having a chemical composition represented by the following general formula (I) and having a weight median diameter of 35 μm or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, M includes silicon (Si) or silicon (Si) and germanium (Ge), and a satisfies 0 <a <0.2).   The fluoride phosphor according to claim 1, wherein the weight median diameter is 100 µm or less. The fluoride fluorescent material according to claim 1 or 2, wherein the bulk density is 0.80 g / cm ³ or more.   The fluoride phosphor according to any one of claims 1 to 3, wherein the weight median diameter is 40 µm or more.   The fluoride fluorescent material according to any one of claims 1 to 4, wherein a weight median diameter is 50 µm or more. A fluoride phosphor having a chemical composition represented by the following general formula (I) and having a bulk density of 0.80 g / cm ³ or more.
K ₂ [M _1-a Mn ⁴⁺ _a F ₆ ] (I)
(In the formula, M includes silicon (Si) or silicon (Si) and germanium (Ge), and a satisfies 0 <a <0.2). The fluoride fluorescent substance according to claim 6, which has a bulk density of 1.00 g / cm ³ or more.   The fluoride phosphor according to any one of claims 1 to 7, wherein the particle shape is non-flat. A light source that emits light in the wavelength range of 380 nm to 485 nm;
A light emitting device comprising the fluoride phosphor according to claim 1.   The light emitting device according to claim 9, further comprising a green phosphor that absorbs light in a wavelength range of 380 nm to 485 nm and emits light in a wavelength range of 495 nm to 573 nm. The green phosphor has a β sialon represented by a composition formula (Si, Al) ₆ (O, N) ₈ : Eu or a composition formula (Ca, Sr, Ba, Zn) ₈ MgSi ₄ O ₁₆ ( The light-emitting device according to claim 10, which is a chlorosilicate represented by F, Cl, Br. I) ₂ : Eu.   The light-emitting device according to claim 9, which is a light source for a liquid crystal display device.   An image display apparatus provided with the light-emitting device of any one of Claims 9-12.

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