JP4148298B2 - Phosphor, light-emitting element using the same, image display device, and illumination device - Google Patents

Description

2. Description of the Related Art In recent years, a white light-emitting element configured by combining a gallium nitride (GaN) light-emitting diode (LED) as a semiconductor light-emitting element and a phosphor as a wavelength conversion material has low power consumption and a long lifetime. Taking advantage of this feature, it is attracting attention as a light-emitting source for image display devices and lighting devices.
The present invention relates to a cerium (Ce) activated oxide phosphor capable of emitting light in a red to blue region by excitation of electron beam, X-ray, ultraviolet ray, visible ray or the like. In particular, the present invention relates to a phosphor capable of absorbing light in the near ultraviolet to blue to blue-green region and efficiently emitting longer-wavelength green to yellow to red light. And as a wavelength conversion material that absorbs light from a semiconductor light emitting device such as a light emitting diode (LED) or a laser diode (LD) that emits light in a blue region, and thus, a light emitting device with high color rendering properties, in particular, white light emission. The present invention relates to a phosphor that can constitute an element (hereinafter referred to as “white LED”). Furthermore, the present invention relates to a light-emitting element, an electroluminescence light-emitting element using the same, and an image display device and a lighting device that have them as a light source.

  As disclosed in Patent Document 1, a white light-emitting element configured by combining a GaN-based blue light-emitting diode and a phosphor utilizes an advantage of low power consumption and long life, It has been attracting attention as a light source for lighting devices. In this light emitting device, the phosphor used therein absorbs visible light in the blue region emitted from the GaN-based blue light emitting diode and emits yellow light. White light emission can be obtained by mixing with yellow light emitted from the phosphor.

As the phosphor, typically, yttrium-aluminum composite oxide (Y ₃ Al ₅ O ₁₂ ) is used as a base crystal, and cerium (Ce) as an activator element is contained in the base crystal. A phosphor is known. Further, by replacing a part of the yttrium (Y) atom with gadolinium (Gd) or the like or a part of the aluminum (Al) atom with gallium (Ga) or the like, the emission color tone of the phosphor can be changed. It is known that it can be adjusted (Non-Patent Document 1). However, in order to produce this phosphor as a single phase with good yield, it is difficult to produce because it must be fired at a very high temperature, and a phosphor with uniform emission intensity, chromaticity, particle size, etc. is produced. There was a problem that it was difficult to do.

In addition, a light emitting device in which a blue light emitting diode and a yellow light emitting phosphor are combined has a problem in that light emission of blue-green to green components is insufficient and color rendering is inferior. In order to improve color rendering, a method of combining a blue light emitting diode, a green phosphor, and a red phosphor is considered. For example, Non-Patent Document 2 discloses a blue light emitting diode and a green phosphor SrGa ₂ S _4. : White LEDs combining Eu ²⁺ and red phosphor ZnCdS: Ag, Cl are disclosed. However, the phosphors used here are sulfides, and are difficult to manufacture, and further have a problem of lack of stability during use.

On the other hand, Patent Document 2 discloses a calcium-scandium-silicon composite oxide (Ca ₃ Sc ₂ Si ₃ O ₁₂ ) activated with Ce as a phosphor that has a relatively low firing temperature and is easy to manufacture.
It is shown. Since this phosphor contains calcium and silicon oxides, a low melting point compound is produced during firing, and the firing temperature is kept low, but the fired powder sinters very firmly. It was also difficult to obtain a phosphor having high emission intensity and having a uniform particle size of about 1 to 20 μm.

On the other hand, Patent Document 3 discloses a phosphor containing thulium (Tm) in an alkaline earth metal scandate having the same CaFe ₂ O ₄ structure as that of the preferred phosphor of the present invention. However, this phosphor exhibits light emission having a narrow half width based on 4f-4f transition by electron beam excitation, and is based on cerium-derived light emission emitted by the phosphor of the present invention, that is, based on 4f-5d transition. The mechanism is completely different from light emission having a wide half-value width. Further, since the thulium-containing phosphor is a material that does not emit light under irradiation with ultraviolet rays or visible light, it is not easy to produce the phosphor of the present invention by analogy from the presence of the phosphor.

Further, phosphors containing cerium in strontium yttrium (SrY ₂ O ₄ ), which is also a crystal having a CaFe ₂ O ₄ structure, are disclosed in Non-Patent Document 3 and Non-Patent Document 4, but these The phosphor does not emit light efficiently at room temperature. Further, strontium thioytlate (SrY _2), which is also a crystal having a CaFe ₂ O ₄ structure.
A phosphor containing cerium in S ₄ ) is disclosed in Non-Patent Document 5, but this phosphor is a sulfide and has practical problems such as long-term stability and difficulty in production. There was a point.
Japanese Patent Laid-Open No. 10-242513 JP 2003-064358 A JP-A-6-100860 264th Annual Meeting of the Society for Phosphors 5-14 Journal of The Electrochemical Society, Vol. 150 (2003) pp. H57-H60 The Journal of Chemical Physics, vol. 47, pp. 5139-5145 (1967) Journal of Luminescence, Vol. 102-103, pp. 635-637 (2003) Journal of The Electrochemical Society, vol. 139, pp. 2347-2352 (1992)

  In view of the above-described prior art, the present invention has been made to develop a phosphor that is easy to manufacture, has high emission intensity, and has a uniform particle diameter, and further, can obtain a light emitting element with high color rendering properties. Phosphor that can be easily manufactured and can obtain a light-emitting element with high color rendering properties, a light-emitting element and an electroluminescence element using the phosphor, and an image display having them as a light source An object is to provide a device and a lighting device.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a compound having a specific chemical composition as a base crystal, and contains at least trivalent cerium (Ce ³⁺ ) as an activator element in the base crystal. It has been found that a phosphor to be achieved can achieve the above object, and the present invention has been achieved.
(1) A composite oxide containing divalent and trivalent metal elements is used as a base crystal, and at least Ce is included as an activator element in the base crystal, and the emission spectrum at room temperature has a wavelength range of 485 nm to 555 nm. A phosphor represented by the following general formula (I), which has a maximum emission peak.
M ¹ _a M ² _b M ³ _c O _d (I)
(In formula (I), M ¹ is an activator element containing at least Ce, M ² is a divalent metal element containing at least Ca, M ³ is a trivalent metal element containing at least Sc, and a is 0.0001 ≦ a ≦ 0.2, b is 0.8 ≦ b ≦ 1.2, c is 1.6 ≦ c ≦ 2.4, d is a number in the range of 3.2 ≦ d ≦ 4.8. is there.)
(2) The phosphor according to (1), wherein 50 mol% or more of the trivalent metal element M ³ in the general formula (I) is Sc.
(3) The phosphor according to (1) or (2), wherein 50 mol% or more of the divalent metal element M ² in the general formula (I) is Ca.
(4) wherein the general formula (I) in the divalent metal elements ^{M 2} are, the Ca, Mg, Zn, Sr, Cd, and is at least one metal element selected from the group consisting of Ba The phosphor according to any one of (1) to (3).
(5) The trivalent metal element M ³ in the general formula (I) is Sc and at least one metal element selected from the group consisting of Al, Ga, Y, In, La, Gd, and Lu. The phosphor according to any one of (1) to (4), wherein
(6) A phosphor-containing resin, wherein a wavelength conversion material containing the phosphor according to any one of (1) to (5) is dispersed in a resin.

  According to the present invention, a phosphor that can be easily manufactured and can obtain a light-emitting element with high color rendering properties, a light-emitting element using the phosphor, and an image display apparatus having the light-emitting element as a light source And a lighting device can be provided.

The phosphor of the present invention uses a composite oxide containing divalent and trivalent metal elements as a base crystal, and contains at least Ce as an activator element in the base crystal, and has an emission spectrum at room temperature of 485 nm to 555 nm. it is one that have a maximum emission peak in a wavelength range of a phosphor represented by the following general formula (I).
M ¹ _a M ² _b M ³ _c O _d (I)
(In the formula (I), M ¹ is an activator element containing at least Ce, M ² is a divalent metal element, M ³ is 3
A is 0.0001 ≦ a ≦ 0.2, b is 0.8 ≦ b ≦ 1.2, c is 1.6 ≦ c ≦ 2.4, and d is 3.2 ≦. It is a number in the range of d ≦ 4.8. )
Here, M ¹ in the formula (I) is an activator element (emission center ion) contained in a host crystal to be described later, and contains at least Ce, and further, phosphorescence, chromaticity adjustment and increase. At least one selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb Of 2 to 4 elements may be included as a coactivator. In addition, when it contains a coactivator, the quantity of the coactivator with respect to Ce1mol is 0.01 mol-20 mol normally. In particular, when Pr is used as a coactivator, it is preferable because light emission of Pr, which is a coactivator, appears in the vicinity of 620 nm in addition to light emission of Ce, and light of a red component can be added.

The concentration a of the activator element M ¹ is 0.0001 ≦ a ≦ 0.2. If the value of a is too small, the amount of luminescent center ions present in the host crystal of the phosphor is too small and the luminescence intensity tends to decrease. On the other hand, if the value of a is too large, the emission intensity tends to decrease due to concentration quenching. Therefore, from the viewpoint of emission intensity, a is preferably 0.0005 ≦ a ≦ 0.1, and most preferably 0.002 ≦ a ≦ 0.04. In addition, as the Ce concentration increases, the emission peak wavelength shifts to the longer wavelength side, and the amount of green light emission with high visibility increases relatively. From the point of balance between the emission intensity and the emission peak wavelength, a is preferably 0.004 ≦ a ≦ 0.15, more preferably 0.008 ≦ a ≦ 0.1, and most preferably 0.02 ≦ a ≦ 0.08.

M ² in the formula (I) is a divalent metal element, but is at least one metal element selected from the group consisting of Mg, Ca, Zn, Sr, Cd, and Ba from the viewpoint of luminous efficiency and the like. It is preferable to include at least one metal element of Mg, Ca, or Sr. Here, the green phosphor is preferably one containing a large amount of Ca as M ^2, and particularly preferably 50 mol% or more of the elements M ² is Ca. As the blue-green phosphor, it preferably contains a large amount of Sr as M ^2, and particularly preferably 50 mol% or more of the elements M ² is Sr.

M ³ in formula (I) is a trivalent metal element, but for the same reason as M ² , it was selected from the group consisting of Al, Sc, Ga, Y, In, La, Gd, Yb, and Lu. It is preferably at least one metal element, more preferably Al, Sc, Y, Yb, or Lu. In particular, it is preferable that at least Sc is included as the M ³ element. For example, it is more preferable that the element of M ³ is Sc alone, Sc and Y, Sc and Al, or Sc and Lu, and Sc alone or Sc. And Y are even more preferred. Further, it is particularly preferable that 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more of the element of M ³ is Sc. When Sc is contained as the M ³ element, the emission intensity is further increased, which is preferable.

Phosphor host crystals of the present invention is generally, M ² is a bivalent metal element and consists of trivalent of M ³ and oxygen is a metal element, the table by a composition formula M ² M ³ ₂ O ₄ In general, the chemical composition ratio in the formula (I) is that b is 1, c is 2, and d is 4, but in the present invention, the activator element Ce is In formula (I), b is 1, c is 2, and d is determined depending on whether it is replaced with the position of the crystal lattice of any metal element of M ² or M ³ or in the gap between the crystal lattices. It may not be 4.

  Therefore, in the present invention, b is a number in the range of 0.8 ≦ b ≦ 1.2, c is in the range of 1.6 ≦ c ≦ 2.4, and d is in the range of 3.2 ≦ d ≦ 4.8. Among them, b is preferably a number in the range of 0.9 ≦ b ≦ 1.1, c is preferably a number in the range of 1.8 ≦ c ≦ 2.2, and d is in the range of 3.6 ≦ d ≦ 4.4. A number is preferred. Further, a, b, c and d are numbers selected so that the charge balance of the phosphor of the present invention is neutral.

M ² and M ³ represent divalent and trivalent metal elements, respectively. If the emission characteristics, crystal structure, etc. are not essentially different from the phosphor of the present invention, M ² and / or M ³ It is also possible to adjust the charge balance etc. by using a part of the metal element as monovalent, tetravalent, or pentavalent, and a small amount of anions such as halogen elements (F, Cl, etc.). , Br, I), nitrogen, sulfur, selenium and the like.

Host crystal of the phosphor of the present invention, as described above, in general, M ² is a divalent metal element to consist of M ³ and oxygen is a trivalent metal element, composition formula M ² M ³ ₂ It is a crystal represented by O ₄ . Usually, the crystal having the composition ratio represented by this formula has a space group due to the difference in constituent metal elements.

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Have one of the following. Of these, a structure having a space group Pnma, that is, a CaFe ₂ O ₄ structure is preferable because a phosphor exhibiting high luminance green light emission can be obtained.

  The phosphor of the present invention is a phosphor having a maximum emission peak in a wavelength range of 485 nm to 555 nm in an emission spectrum at room temperature. In addition, the room temperature in this invention is 25 degreeC. When there is a maximum emission peak wavelength on the shorter wavelength side than 485 nm, when this phosphor is excited with a blue LED having a wavelength of 420 nm to 485 nm, it overlaps with the emission wavelength of the blue LED, so that a good color rendering property is obtained. Hard to get. On the other hand, when the maximum emission peak wavelength exceeds 555 nm, it is difficult to obtain good color rendering because the blue-green to green emission components are insufficient. Accordingly, the maximum emission peak wavelength is preferably in the wavelength range of 485 to 545 nm, and particularly preferably in the wavelength range of 500 to 535 nm.

In addition, a phosphor suitable for the purpose of the present invention can be obtained by replacing part of oxygen in the host crystal with sulfur to such an extent that the characteristics of the present invention are not impaired. Is not preferable because it deteriorates the deterioration characteristics of the phosphor.
The phosphor of the present invention can be synthesized by a general solid phase reaction method. For example, raw material compounds such as the activator element M ¹ source compound, the divalent metal element M ² source compound, and the trivalent metal element M ³ source compound in the general formula (I) are used as a hammer mill, a roll mill, and a ball mill. After pulverizing using a dry pulverizer such as a jet mill, the mixture is mixed using a blender such as a ribbon blender, V-type blender or Henschel mixer, or after mixing these raw material compounds, using a dry pulverizer Dry method of grinding;
Alternatively, these raw material compounds are added to a medium such as water and pulverized and mixed using a wet pulverizer such as a medium stirring pulverizer, or these raw material compounds are pulverized with a dry pulverizer, It can be produced by preparing a pulverized mixture by a wet method in which a slurry prepared by adding and mixing in a medium such as spray is dried by spray drying or the like, and heat-treating and baking the obtained pulverized mixture. it can.

In particular, in the element source compound of the activator element, it is preferable to use a liquid medium because it is necessary to uniformly mix and disperse a small amount of the compound in the whole, and in the other element source compounds, it is uniform throughout. Among the above-described pulverization and mixing methods, a wet method is preferable from the viewpoint of obtaining easy mixing.
Further, when preparing the pulverized mixture described above, an additive (generally called “flux”) that promotes crystal growth of the phosphor particles during the heat treatment can be added. The flux, for example, NH ₄ ammonium halide, such as Cl or _{NH 4 F · HF, NaCO 3} , LiCO 3 alkali metal carbonate such as, LiCl, NaCl, alkali halides KCl, _etc., CaCl 2, CaF ₂ , Alkaline earth metal halides such as BaF ₂ , borate compounds such as B ₂ O ₃ , H ₃ BO ₃ , NaB ₄ O ₇ , Li ₃ PO ₄ , NH ₄ H ₂ PO ₄ Phosphate, etc. can be used. Among these, CaF ₂ and H ₃ BO ₃ are particularly preferable.

The heat treatment is performed in a heat-resistant container such as a crucible or tray made of alumina, quartz, silicon carbide, platinum, etc., usually at a temperature of 1200 ° C. to 1800 ° C., in the atmosphere, or with oxygen, carbon monoxide, The heating is performed for 10 minutes to 24 hours in a single or mixed atmosphere of a gas such as carbon dioxide, nitrogen, hydrogen, or argon. As the heat-resistant container, the reactivity between the raw material mixture and the heat-resistant container is low, and a phosphor with high purity and high light emission characteristics is obtained. Therefore, a high-purity alumina or platinum container is preferable, and a platinum container is more preferable. preferable. Moreover, metal containers, such as molybdenum and tungsten, and containers, such as boron nitride, can also be used. The firing temperature is usually in the temperature range of 1200 ° C to 1800 ° C. If the firing temperature is lower than 1200 ° C., the solid phase reaction between the raw material mixtures is insufficient, and the target phosphor may not be synthesized. Further, if the firing temperature is higher than 1800 ° C., an expensive firing furnace is required, and unnecessary firing energy may be consumed. For this reason, as a calcination temperature, 1400 degreeC-1700 degreeC are preferable, and 1500 degreeC-1650 degreeC are still more preferable. The firing atmosphere is usually air or a single or mixed atmosphere of gases such as oxygen, carbon monoxide, carbon dioxide, nitrogen, hydrogen, argon, etc., but Ce ³⁺ ions are stably ^contained in the base crystal. In order to enhance the light emission characteristics by activation, a reducing atmosphere is preferable. In particular, a hydrogen-containing nitrogen atmosphere is more preferable because the body crystal of the base crystal becomes clear green and the light emission characteristics are remarkably improved. In addition, after baking in an oxidizing atmosphere or neutral atmosphere, reheating in a reducing atmosphere is also useful for stabilizing the activator element Ce as a trivalent luminescent center ion in the host crystal. It is. Furthermore, it is useful for improving the characteristics to perform heating in a reducing atmosphere a plurality of times. In addition, after heat processing, washing | cleaning, drying, a classification process, etc. are made | formed as needed. It is preferable to wash the phosphor using an acid at the time of washing, because an impurity phase other than the phosphor host crystal such as a flux adhering to the phosphor surface can be removed and the light emission characteristics can be improved. Further, as surface treatment, fine particles such as silica, alumina, calcium phosphate, etc. are attached to the surface, whereby powder characteristics (aggregation state, dispersibility in solution, sedimentation behavior, etc.) can be improved. For the post-treatment after the heat treatment, a generally known technique is used for known phosphors, for example, phosphors used in cathode ray tubes, plasma display panels, fluorescent lamps, fluorescent display tubes, X-ray intensifying screens, and the like. It can be used and can be appropriately selected according to the purpose, application, and the like.

Examples of the M ¹ source compound, M ² source compound, and M ³ source compound include oxides, hydroxides, carbonates, nitrates, sulfates, oxalates, and carboxylates of M ¹ , M ² , and M ^3. Among them, the halide is selected in consideration of the reactivity to the composite oxide and the non-generation of NOx, SOx, etc. during firing.
Specific examples of the Ce source compound for Ce contained in the activator element M ¹ include Ce ₂ O ₃ , CeO ₂ , Ce (OH) ₃ , Ce (OH) ₄ , and Ce ₂ (CO ₃ ). ₃ , Ce (NO ₃ ) ₃ , Ce ₂ (SO ₄ ) ₃ , Ce (SO ₄ ) ₂ , Ce ₂ (OCO) ₆ , Ce (OCOCH ₃ ) ₃ , CeCl ₃ , CeCl _{4 and the} like.

Regarding the Mg, Ca, and Sr that are preferable as the divalent metal element M ² , specific examples of those M ² source compounds include MgO, Mg (OH) ₂ , MgCO _3. Mg (OH) ₂ .3MgCO ₃ .3H ₂ O, Mg (NO ₃ ) ₂ .6H ₂ O, MgSO ₄ , Mg (OCO) ₂ .2H ₂ O, Mg (OCOCH ₃ ) ₂ .4H ₂ O, MgCl _{2 and the} like, and Ca source compounds include CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, Ca (OCO) ₂ .H ₂ O. , Ca (OCOCH ₃ ) ₂ .H ₂ O, CaCl _{2 and the} like, and Sr source compounds include SrO, Sr (OH) ₂ , SrCO ₃ , Sr (NO ₃ ) ₂ , Sr (OCO) ₂ , Sr Examples thereof include (OCOCH ₃ ) ₂ and SrCl ₂ .

Further, regarding the Sc, Lu, Y, and Al preferable as the trivalent metal element M ³ , specific examples of those M ³ source compounds include Sc ₂ O ₃ , Sc ( OH) ₃ , Sc ₂ (CO ₃ ) ₃ , Sc (NO ₃ ) ₃ , Sc ₂ (SO ₄ ) ₃ , Sc ₂ (OCO) ₆ , Sc (OCOCH ₃ ) ₃ , ScCl _3, etc., and a Lu source the _{compound, Lu 2 O 3, Lu 2} (SO 4) 3, LuCl 3 or the like, also as the Y source _{compound, Y 2 O 3, Y (} OH) 3, Y 2 (CO 3) 3, Y (NO ₃ ) ₃ , Y ₂ (SO ₄ ) ₃ , Y ₂ (OCO) ₆ , Y (OCOCH ₃ ) ₃ , YCl _3, etc., and Al source compounds include Al ₂ O ₃ , Al (OH) ₃ , AlOOH, Al (NO ₃ ) ₃ .9H ₂ O, Al ₂ (SO ₄ ) ₃ , AlCl _{3 and the} like.

The particle diameter of the phosphor of the present invention produced by the above production method is usually 0.1 μm or more and 50 μm or less, but the lower limit is preferably 1 μm or more, more preferably 2 μm or more, and the upper limit is Is preferably 30 μm or less, more preferably 15 μm or less.
A more preferable phosphor can be obtained by performing necessary classification treatment or crushing treatment so as to be in this particle size range. As the classification process, any means such as a wet classification process such as a water tank and an airflow classification process such as a cyclone or an inertia classifier can be applied. Moreover, there is no restriction | limiting in processing methods, such as a ball mill process, also about a crushing process.

In addition, the particle size of the above-mentioned phosphor refers to the particle size measured by a laser diffraction type particle size distribution measuring device, for example, model LA-300 manufactured by Horiba.
The phosphor of the present invention can also be synthesized by a spray pyrolysis method. For example, first, a compound containing the constituent element of the phosphor to be manufactured is dissolved in a solvent such as water to prepare a raw material solution. The solvent of the raw material solution is not limited as long as it is a liquid having a viscosity low enough to form droplets in a later procedure, but water is preferably used in consideration of cost and safety of exhaust gas.

As the compound containing the constituent element of the phosphor, any compound can be used as long as it is a raw material that is soluble in the solvent to be used and decomposes into an oxide when heated to a high temperature. .
In order to obtain good light emission characteristics, it is preferable that these raw material compounds and raw material solutions have a small amount of impurity elements such as iron and nickel which become killer centers.

  In addition to the constituent elements of the phosphor, various additives can be added to the raw material solution. For example, alkali metal salts, halides of various metals, borate compounds, etc. can be expected to have a flux action that promotes crystal growth, and polyacids such as citric acid and polyols such as ethylene glycol are homogeneously mixed with raw metal These are effective because they are effective in controlling particle morphology.

The content ratio of the raw material metal in the raw material solution is preferably the composition ratio of the target phosphor.
When the total concentration of the above constituent elements in the raw material solution is increased, the secondary particle diameter of the obtained phosphor is increased. Conversely, when the concentration is decreased, the secondary particle diameter tends to be decreased. On the other hand, if the solute concentration is too low, the amount of solvent to be evaporated increases and unnecessary energy is required, which is not preferable. On the other hand, when the solute concentration is too high, formation of droplets becomes difficult. Therefore, in order to synthesize a good phosphor, the total number of moles of the phosphor constituent elements contained in the raw material solution is preferably 0.01 mol / l or more and 10 mol / l or less.

  Next, droplets are formed from the obtained raw material solution. Droplet formation can be performed by various spraying methods. For example, a method of forming liquid droplets of 1 μm to 50 μm by spraying while sucking up liquid with pressurized air, a method of forming liquid droplets of 4 μm to 10 μm using ultrasonic waves of about 2 MHz from a piezoelectric crystal, and hole diameter Oscillates an orifice of 10 μm to 20 μm by a vibrator, supplies a liquid at a constant speed thereto, and discharges the liquid from the orifice hole by a certain amount according to the frequency, thereby forming a droplet of 5 μm to 50 μm, A method of dropping a liquid on a rotating disk at a constant speed and forming a liquid droplet of 20 μm to 100 μm from the liquid by centrifugal force, a liquid droplet of 0.5 μm to 10 μm by applying a high voltage to the liquid surface It is possible to adopt a method for generating For the production of phosphors with submicron to micron order particle sizes that can be used in cathode ray tubes, fluorescent lamps, FEDs, etc., droplets with a relatively uniform droplet diameter of 4 μm to 10 μm are formed. A spraying method using ultrasonic waves that can be used is preferable.

  The formed droplets can be made into phosphor particles by heating them by introducing them into a pyrolysis reactor with a carrier gas. In this pyrolysis reactor, depending on factors that affect the heating rate such as the type of solution, the type of carrier gas, the carrier gas flow rate, the temperature in the pyrolysis reactor, hollow particles, porous particles, solid particles, The crushed particles and the like, and the form and surface state of the generated particles change.

As the carrier gas, hydrogen, nitrogen, argon, oxygen, air, or a mixed gas thereof can be used. In order to obtain good light emission characteristics, nitrogen, argon, a mixed gas of nitrogen and hydrogen is used. Further, a mixed gas of argon and hydrogen is preferable, and more preferable is nitrogen or a mixed gas of nitrogen and hydrogen in terms of cost. Between hydrogen and nitrogen or argon
From the viewpoint of safety, the mixing ratio of hydrogen in the mixed gas is preferably 10% or less, preferably 5% or less, and particularly preferably 4% or less, which is the lower limit of hydrogen gas explosion. On the other hand, from the viewpoint of enhancing the reducibility, the hydrogen mixing ratio is preferably high, preferably 1% or more, and more preferably 2% or more.

  The heating temperature is usually set so that the lower limit is 1200 ° C. or higher and the upper limit is 1900 ° C. If this thermal decomposition reaction temperature is too low, the crystallinity is low, and the activator element such as Ce is not effectively dispersed in the crystal, so that the light emission characteristics tend to be low. On the other hand, if the thermal decomposition reaction temperature is too high, not only unnecessary energy is consumed, but also phosphor components are evaporated and abrupt condensation occurs at the time of cooling. In this respect, the more preferable lower limit of the heating temperature is 1500 ° C. or higher, and the upper limit is 1700 ° C. or lower.

  The pyrolysis reaction is usually performed for a reaction time within a range of 0.1 seconds to 10 minutes, that is, a pyrolysis reactor residence time. Among these, the reaction time is preferably within a range of 1 second to 1 minute. If the reaction time is too short, the resulting phosphor has low crystallinity and an activator element such as Ce is not activated in the crystal, so that the light emission characteristics tend to be low. On the other hand, if the reaction time is too long, it will be understood that productivity is lowered only by consuming unnecessary energy, and an unexpected reaction such as decomposition of the phosphor occurs, which tends to cause a decrease in luminance.

  As described above, the solid phase reaction method and the spray pyrolysis method have been described as the phosphor synthesis method of the present invention. However, the synthesis method is not limited to these, and is known as a synthesis method of inorganic compound powder. General methods that can be applied. For example, it can be manufactured by preparing a precursor material in which raw materials are uniformly mixed by a sol-gel method, a complex polymerization method, a uniform precipitation method, and the like, and subjecting this to a heat treatment. The heat treatment method at this time can be performed by substantially the same method as the heat treatment method in the above-mentioned solid phase reaction method, but by using a precursor in which raw material metals are uniformly mixed, A phosphor with excellent characteristics can be synthesized at a lower temperature than in the case of the reaction method.

  The light-emitting element of the present invention includes the phosphor as a wavelength conversion material and a semiconductor light-emitting element such as an LED or an LD, and absorbs light in a range from ultraviolet light to visible light emitted from the semiconductor light-emitting element. It is a light emitting element with high color rendering properties that emits visible light having a longer wavelength, and is suitable as a light source for an image display device such as a color liquid crystal display using a backlight unit or a lighting device such as a surface emitting device. The light emitting element may contain other phosphors in addition to the phosphor of the present invention. Moreover, the impurity accompanying manufacturing the fluorescent substance of this invention may be contained to such an extent that performance is not impaired.

  Hereinafter, the light emitting device of the present invention will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view showing an embodiment of a light emitting device having the phosphor of the present invention as a wavelength conversion material and a semiconductor light emitting device, and FIG. 4 is a surface emitting illumination incorporating the light emitting device shown in FIG. It is typical sectional drawing which shows one Example of an apparatus, In FIG.3 and FIG.4, 1 is a light emitting element, 2 is a mount lead, 3 is an inner lead, 4 is a semiconductor light emitting element, 5 is fluorescent substance containing resin part, 6 is a conductive wire, 7 is a mold member, 8 is a surface emitting illumination device, 9 is a diffusion plate, and 10 is a holding case.

For example, as shown in FIG. 3, the light-emitting element 1 of the present invention has a general bullet shape, and a semiconductor light-emitting element 4 made of a GaN-based blue light-emitting diode or the like is disposed in the upper cup of the mount lead 2. The upper part of the semiconductor light emitting device 4 is formed by mixing and dispersing a wavelength conversion material containing at least the phosphor of the present invention in a binder such as an epoxy resin or an acrylic resin, and pouring it into the cup. It is fixed by being covered with the phosphor-containing resin part 5. On the other hand, the semiconductor light emitting element 4 and the mount lead 2 and the semiconductor light emitting element 4 and the
Each of the inner leads 3 is electrically connected by a conductive wire 6 and is entirely covered and protected by a mold member 7 made of epoxy resin or the like.

  Further, for example, as shown in FIG. 4, the surface emitting illumination device 8 incorporating the light emitting element 1 has a large number on the bottom surface of a rectangular holding case 10 whose inner surface is light-impermeable such as a white smooth surface. The light emitting element 1 is provided, and a power source and a circuit (not shown) for driving the light emitting element 1 are provided outside the light emitting element 1, and milky white acrylic is provided at a position corresponding to the lid portion of the holding case 10. A diffusion plate 9 such as a plate is fixed for uniform light emission.

  Then, the surface-emitting illumination device 8 is driven to apply blue voltage to the semiconductor light-emitting element 4 of the light-emitting element 1 to emit blue light or the like, and a part of the emitted light is converted in wavelength in the phosphor-containing resin portion 5. The phosphor of the present invention as a material absorbs and emits light having a longer wavelength. On the other hand, light emission with high color rendering properties is obtained by mixing with blue light or the like that is not absorbed by the phosphor, and this light is diffused. Through the plate 9, the light is emitted upward in FIG. 4, and illumination light with uniform brightness is obtained in the surface of the diffusion plate 9 of the holding case 10.

  In addition, the phosphor obtained in the present invention is not limited to the above-described light emitting device using the light of the semiconductor light emitting device, but also Proceedings of The 10th International Display Works, pp. 1109-1112 (2003) can also be used as a green wavelength conversion material used in a full-color inorganic electroluminescence device. That is, for example, the full color electroluminescent light emitting device of the present invention comprises a blue light emitting electroluminescent light emitting device, the phosphor as a green wavelength converting material, and an arbitrary red wavelength converting material, A full-color display is performed by forming green and red light emitting regions and electrically controlling their light emission intensity. Furthermore, by using the full-color electroluminescence light emitting element having the above-described structure as a white light emitting element or a surface light emitting element that emits light of a specific color tone, it can be used as a backlight unit of a color liquid crystal display to constitute an image display device. It can be used as a surface emitting lighting device. Note that the electroluminescence light emitting element may contain other phosphors in addition to the phosphor of the present invention.

Furthermore, since the phosphor obtained by the present invention emits light not only by ultraviolet rays and visible rays but also by electron beams, X-rays, electric fields, etc., it can also be used as a phosphor utilizing such excitation means.
The phosphor of the present invention can also be used for an image display device having a light source (excitation source) and a phosphor. Examples of the image display device include a fluorescent display tube (VFD), a field emission display (FED), a plasma display panel (PDP), a cathode ray tube (CRT), and the like. It can also be used for a backlight for an image display device.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples and comparative examples, the emission spectrum, excitation spectrum, and emission intensity were measured at room temperature (25 ° C.).
Example 1
In order that the chemical composition of the phosphor to be produced is Ce _0.01 Ca _0.99 Sc ₂ O ₄ , CeO ₂ is 0.01 mol as the M ¹ source compound and Ca as the M ² source compound at a molar ratio to 1 mol of the phosphor.
Each raw material powder was weighed so that 0.99 mol of CO ₃ and 1 mol of Sc ₂ O ₃ as an M ³ source compound would be 1 mol. They were wet pulverized and mixed in a powder mixer using ethanol as a dispersion medium, and then the dispersion medium was vaporized and removed to obtain a dried raw material pulverized mixed powder. The resulting ground mixture
Baking by heating in a platinum crucible in a nitrogen atmosphere mixed with 4% hydrogen at a maximum temperature of 1600 ° C. for 3 hours, followed by washing with water, drying, and classification to obtain phosphor powder Manufactured.

The median diameter measured by a laser diffraction particle size distribution analyzer LA-300 (manufactured by Horiba, Ltd.) of the obtained phosphor was 14 μm. This phosphor was found to be agglomerated primary particles having a diameter of about 3 μm by observation with a scanning electron microscope. Further, the powder X-ray diffraction pattern of this phosphor is as shown in FIG. 1, which matches the diffraction pattern shown in JCPDS card No. 72-1360, and has the same space group Pnma as CaSc ₂ O ₄ . It was confirmed that the compound had a crystal structure. Further, when the emission spectrum and excitation spectrum of this phosphor were measured using an F-4500 type fluorescence spectrophotometer (manufactured by Hitachi, Ltd.), the spectrum shown in FIG. 2 was obtained and activated in the parent crystal. It was confirmed that it contains trivalent Ce as an agent element. Since the emission peak wavelength of this phosphor is 516 nm and the fluctuation of the excitation intensity is small in the blue wavelength range of 450 to 465 nm, the phosphor is highly affected by light from the blue LED emitting in this wavelength region. It was confirmed that it was excited efficiently and emitted green light. The fluorescence intensity at the emission peak wavelength when this phosphor is irradiated with excitation light having a wavelength of 455 nm shows a value of 143 when the emission intensity of the phosphor of Comparative Example 1 is 100. It was confirmed that the emission intensity was significantly higher than that of the yellow phosphor.

When this phosphor was irradiated with blue light from a GaN-based blue light emitting diode (peak wavelength: 460 nm) and the irradiation intensity was adjusted, the blue light was absorbed and green light was emitted, and the phosphor was not absorbed. Blue-green light was emitted due to color mixing with blue light of the diode.
In addition, this green phosphor and Eu-activated CaS red phosphor are mixed with an epoxy resin, applied onto an InGaN blue light emitting diode (peak wavelength: 460 nm), and then cured by heating. Further, this is sealed in a transparent epoxy resin. Stopped to create a bullet-type white LED. When this LED was energized, the luminous intensity was large and the average color rendering index was 90, which was very good. The Eu-activated CaS red phosphor was prepared by mixing CaS and EuF ₃ at a molar ratio of 99.6: 0.4, and in an alumina crucible at 1000 ° C. in a nitrogen atmosphere containing 4% hydrogen. For 2 hours, and pulverization and classification were performed.

Comparative Example 1
Y ₂ O ₃ : 1.05 mol, Gd ₂ O ₃ : 0.39 mol, Al ₂ O ₃ : 2.5 mol, CeO ₂ : 0.12 mol, pure BaF ₂ : 0.25 mol as a flux Along with water, the mixture was pulverized and mixed in an alumina container and a wet ball mill of beads, dried, and then passed through a nylon mesh. The obtained pulverized mixture was fired in an alumina crucible by heating at 1450 ° C. for 2 hours in the atmosphere. Subsequently, (Y _0.7 Gd _0.26 Ce _0.04 ) ₃ Al ₅ O ₁₂ phosphor was obtained by washing with water, drying, and classification. This phosphor was compared with the emission intensity at the same excitation wavelength of the phosphors of Examples 1 to 14 by setting the emission intensity of excitation at 455 nm to 100. When this phosphor was irradiated with the light emitted from the blue light emitting diode, the phosphor light was mixed with the blue light of the diode that was not absorbed by the phosphor, and the phosphor appeared white.

Examples 2-6
A phosphor was manufactured in the same manner as in Example 1 except that the material of the crucible and the firing temperature at the time of manufacturing the phosphor were changed as shown in Table 1.
The obtained phosphor has CaSc ₂ O ₄ as a base crystal by powder X-ray diffraction, analysis of emission spectrum and excitation spectrum, and trivalent Ce as an activator element in the base crystal. It was confirmed. The emission peak wavelength and emission intensity of the obtained phosphor are shown together in Table 1. A phosphor rapid evaluation apparatus manufactured by JASCO was used for measurement of the emission spectra of the phosphors of Example 2 and later. This apparatus includes a Xe lamp as a light source, and a light receiving element of a C7041 type multichannel detector manufactured by Hamamatsu Photonics.
The emission intensity was high for the phosphor when the platinum crucible was used, and the highest for the phosphor fired at 1600 ° C. in this temperature range.

Examples 7-11
A phosphor was manufactured in the same manner as in Example 1 except that the mixture composition of the Ce and Ca raw materials of the phosphor was changed as shown in Table 2. The obtained phosphor has CaSc ₂ O ₄ as a base crystal by powder X-ray diffraction, analysis of emission spectrum and excitation spectrum, and trivalent Ce as an activator element in the base crystal. It was confirmed. The emission peak wavelength and emission intensity of the obtained phosphor are shown together in Table 2. The phosphor obtained by adjusting the Ce raw material mixing molar ratio to 0.01 had the highest emission intensity. Further, as the Ce concentration was increased, the emission peak wavelength shifted to the longer wavelength side, and green light emission with better color purity was exhibited.

Examples 12-14
A phosphor was manufactured in the same manner as in Example 1 except that the raw material mixture composition was changed as shown in Table 3 in order to replace part of Ca of the phosphor with Mg. However, in addition to the raw materials described in Example 1, MgCO ₃ was used as the Mg element source. The obtained phosphor was confirmed by powder X-ray diffraction.
However, the space group was the same as in Example 1, but the lattice constant was shortened, and a small amount of MgO was mixed in addition to the phosphor. Further, when the emission spectrum was measured, the emission peak wavelength was shifted to the longer wavelength side. From these facts, it was confirmed that a part of the raw material Mg was dissolved in the base crystal. Table 3 shows the emission peak wavelength and emission intensity of the obtained phosphor. Although the emission intensity decreased due to the substitution of Ca by Mg, the emission peak wavelength shifted to the longer wavelength side, and preferred green emission was exhibited.

Example 15
Mix each aqueous solution of cerium nitrate, calcium nitrate and scandium nitrate so that the metal element ratio (molar ratio) in the raw material solution is Ce: Ca: Sc = 0.01: 0.99: 2 did. This mixed aqueous solution was dried in a platinum container, and then fired in a nitrogen atmosphere mixed with 4% hydrogen at a maximum temperature of 1400 ° C. for 3 hours to produce a phosphor.

The obtained phosphor was confirmed to be a compound having a crystal structure of the same space group Pnma as CaSc ₂ O ₄ by analysis by powder X-ray diffraction. Further, when an emission spectrum and an excitation spectrum of the phosphor were obtained using a fluorescence spectrophotometer, it was confirmed that the host crystal contained trivalent Ce as an activator element. Since the emission peak wavelength of this phosphor is 513 nm and the fluctuation of excitation intensity is small in the blue wavelength range of 450 to 465 nm, the phosphor is highly affected by light from the blue LED emitting in this wavelength region. It was confirmed that it was excited efficiently and emitted green light. The fluorescence intensity at the emission peak wavelength when this phosphor was irradiated with excitation light having a wavelength of 455 nm was defined as 100.

Example 16
A phosphor as in Example 15 except that aqueous solutions of manganese nitrate, cerium nitrate, calcium nitrate, and scandium nitrate were used so that the metal element ratio in the raw material solution was the molar ratio shown in Table 4. Manufactured.

Table 4 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor is irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.
As shown in Table 4, the emission intensity of the phosphor was increased by coactivation of Mn.

Examples 17-30
Except for using rare earth element nitrate, cerium nitrate, calcium nitrate, and scandium nitrate aqueous solutions of the coactivator so that the metal element ratio in the raw material solution is the molar ratio shown in Table 4. A phosphor was manufactured in the same manner as in Example 15.
Table 4 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor is irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.
As shown in Table 4, the emission intensity of the phosphor was increased by co-activation of Pr, Tb, Dy, and Tm. In particular, when Pr was added, Pr-derived luminescence appeared together with Ce luminescence. Further, even when a small amount of Nd, Sm, Ho, Er, or Yb was added, no significant reduction in emission intensity was observed.

Examples 31-44
Except that the nitrate mixed solution was prepared by adding each nitrate of Mg, Sr and Ba in addition to the nitrate used in Example 15 so that the metal element ratio in the raw material solution became the molar ratio shown in Table 5. A phosphor was manufactured in the same manner as in Example 15.
Table 5 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor was irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.

  As shown in Table 5, when the Ca content was decreased and the Mg content and Sr content were increased, the emission intensity increased with a small amount of phosphor with a small amount of Mg or Sr. As the Sr content increased, the emission intensity gradually decreased. Moreover, when the Sr content was increased, the emission peak wavelength shifted to the short wavelength side, and blue-green increased. On the other hand, when the Ba content was increased, the emission intensity decreased monotonously, but even when the Ba molar ratio was increased to 0.4, the emission intensity was maintained at about 30 or more.

Examples 45-55
Except that the nitrate mixed aqueous solution was prepared by adding each nitrate of Al, Y, and Lu in addition to the nitrate used in Example 15 so that the metal element ratio in the raw material solution became the molar ratio shown in Table 6. A phosphor was manufactured in the same manner as in Example 15.
Table 6 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor was irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.

As shown in Table 6, when the Sc content is decreased and the Al content, Y content, and Lu content are increased, the emission intensity increases with a small amount of phosphor, with the Al content, Y content, and Lu content being increased. However, when the Al content and the Y content were further increased, the emission intensity decreased.
The emission peak wavelength tended to shift to a short wavelength as the Al content increased. On the other hand, as the Y content and Lu content increased, the emission peak wavelength shifted to the longer wavelength side.

Examples 56-63
A nitrate mixed aqueous solution was prepared by adding each nitrate of Mg, Sr, Ba, and Al in addition to the nitrate used in Example 15 so that the metal element ratio in the raw material solution became the molar ratio shown in Table 7. Except for the above, a phosphor was manufactured in the same manner as in Example 15.
Table 7 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor was irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.

Examples 64-69
A nitrate mixed aqueous solution was prepared by adding each nitrate of Mg, Sr, Ba, and Y in addition to the nitrate used in Example 15 so that the metal element ratio in the raw material solution became the molar ratio shown in Table 8. Except for the above, a phosphor was manufactured in the same manner as in Example 15.
Table 8 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor is irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.

Examples 70-86
A nitrate mixed aqueous solution was prepared by adding each nitrate of Mg, Sr, Ba, and Lu in addition to the nitrate used in Example 15 so that the metal element ratio in the raw material solution became the molar ratio shown in Table 9. Except for the above, a phosphor was manufactured in the same manner as in Example 15.
Table 9 shows the emission peak wavelength of the phosphor and the emission intensity at that wavelength when the obtained phosphor was irradiated with excitation light having a wavelength of 455 nm. However, this fluorescence intensity is shown as a relative value when the emission intensity at the emission peak wavelength when the phosphor of Example 15 is irradiated with excitation light having a wavelength of 455 nm is taken as 100.

Example 87
Precursor solutions containing metal salts at the following concentrations were prepared.
Ca (NO ₃ ) ₂ 0.0495 mol / L
Sc (NO ₃ ) ₃ 0.1 mol / L
Ce (NO ₃ ) ₃ 0.0005 mol / L

This solution was placed in an ultrasonic nebulizer equipped with a 1.7 MHz vibrator to form microdroplets. The droplets were passed through the core tube of a vertical tubular electric furnace by a flow of nitrogen gas containing 4% hydrogen. In the electric furnace, the length of the uniform temperature region was about 150 cm, and the temperature was set to 1500 ° C. The gas flow rate was 2 L / min. By passing through the electric furnace, the droplets were dried and turned into powder, which was collected by an electric dust collector. The powder was a CaSc ₂ O ₄ : Ce phosphor produced by reaction between nitrate compounds contained in the precursor solution. The obtained phosphor absorbed blue light and exhibited good green light emission. The emission characteristics are shown in Table 10. The emission intensity in Table 10 is a relative value with the emission intensity of the phosphor of Comparative Example 1 being 100. When the particle size of the obtained phosphor was measured by the same method as in Example 1, the median particle size (D ₅₀ ) was 1.0 μm, and the phosphor had a narrow particle size distribution.

Example 88
The phosphor was spray pyrolyzed and synthesized in the same procedure as in Example 87 except that the circulated gas was nitrogen gas. The obtained phosphor was placed in a crucible and heated (annealed) at 1500 ° C. in a nitrogen gas atmosphere containing 4% hydrogen. The obtained phosphor absorbed blue light and exhibited good green light emission. The emission characteristics are shown in Table 10.

Examples 89-91
A phosphor was obtained in the same manner as in Example 88 except that the annealing temperature was changed as shown in Table 10. The emission characteristics of this phosphor are shown in Table 10.

Examples 92, 93
A raw material compound and a flux compound were mixed well so as to have the composition shown in Table 11, and a heat treatment was performed in the same procedure as in Example 1 to obtain a phosphor. However, the firing temperature was 1550 ° C. In addition, the molar ratio of the flux is the number of moles of the flux compound with respect to 1 mole of the phosphor CaSc ₂ O _{4 to be} generated. The obtained phosphor was immersed in 1 N hydrochloric acid for 1 day to remove impurities such as excess flux. Thereafter, the solid-liquid separation and the operation of adding water and stirring were repeated until the pH of the supernatant liquid reached 4 or more. The washed phosphor was dried with a drier at 120 ° C. and sieved to loosen the dried aggregates. Table 11 shows the emission characteristics of the obtained phosphor. The emission intensity was expressed as a relative value with the phosphor of Comparative Example 1 as 100.

Comparative Example 2
SrCO ₃ : 0.0297 mol, Y ₂ O ₃ : 0.03 mol and CeO ₂ : 0.0003 mol were sufficiently wet-mixed with ethanol in a mortar and dried. This mixture was placed on a platinum foil and fired by heating at 1450 ° C. for 2 hours in a nitrogen gas atmosphere containing 4% hydrogen to obtain SrY ₂ O ₄ : Ce. It was confirmed by powder X-ray diffraction that the obtained substance had a crystal structure reported as SrY ₂ O ₄ . The resulting material was an orange powder. The obtained substance was irradiated with excitation light having wavelengths of 254 nm, 365 nm, and 460 nm, but did not emit light at all with light of any wavelength.

It is a powder X-ray diffraction pattern (X-ray source = CuKα) of the phosphor obtained in Example 1 of the present invention. In FIG. 1, the standard diffraction pattern of CaSc ₂ O ₄ shown in JCPDS card 72-1360 is shown at the same time. It is shown that the diffraction pattern of the phosphor obtained in Example 1 is in good agreement with the standard diffraction pattern. It is a figure which shows the emission spectrum (solid line) of the fluorescent substance obtained in Example 1 of this invention, and the excitation spectrum (dotted line). It is typical sectional drawing which shows one Example of the light emitting element which has the fluorescent substance of this invention as a wavelength conversion material, and a semiconductor light emitting element. It is typical sectional drawing which shows one Example of the surface emitting illumination device incorporating the light emitting element shown in FIG.

Explanation of symbols

1: Light emitting device
2: Mount lead
3: Inner lead
4: Semiconductor light emitting device
5: Phosphor-containing resin part
6: Conductive wire
7: Mold member
8: Surface emitting lighting device
9: Diffuser
10: Holding case

Claims (6)

A composite oxide containing divalent and trivalent metal elements is used as a base crystal,
The base crystal contains at least Ce as an activator element,
It has a maximum emission peak in a wavelength range of 485 nm to 555 nm in an emission spectrum at room temperature,
A phosphor represented by the following general formula (I).
M ¹ _a M ² _b M ³ _c O _d (I)
(In formula (I), M ¹ is an activator element containing at least Ce, M ² is a divalent metal element containing at least Ca, M ³ is a trivalent metal element containing at least Sc, and a is 0.0001 ≦ a ≦ 0.2, b is 0.8 ≦ b ≦ 1.2, c is 1.6 ≦ c ≦ 2.4, d is a number in the range of 3.2 ≦ d ≦ 4.8. is there.) The phosphor according to claim 1, at least 50 mol% of trivalent metal elements M ³ in the general formula (I) is characterized in that it is a Sc. The phosphor according to claim 1 or ² , wherein 50 mol% or more of the divalent metal element M2 in the general formula (I) is Ca. Claims wherein the general formula (I) in the divalent metal elements ^{M 2,} characterized with Ca, Mg, Zn, Sr, Cd, and is at least one metal element selected from the group consisting of Ba Item 4. The phosphor according to any one of Items 1 to 3. The trivalent metal element M ³ in the general formula (I) is at least one metal element selected from the group consisting of Sc and Al, Ga, Y, In, La, Gd, and Lu. The phosphor according to any one of claims 1 to 4, characterized in that:   6. A phosphor-containing resin, wherein a wavelength conversion material containing the phosphor according to claim 1 is dispersed in a resin.

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