JP4904766B2 - Phosphor, light-emitting device using the same, image display device, and lighting device - Google Patents

Description

  The present invention relates to a phosphor in which a base compound contains a metal element mainly composed of cerium (Ce) as an emission center ion, and a light emitting device using the phosphor. Specifically, as a wavelength conversion material, a phosphor that absorbs light in a range from ultraviolet light to visible light and emits longer wavelength visible light, and a light source such as a light emitting diode (LED) or a laser diode (LD) The present invention relates to a phosphor capable of obtaining a light-emitting device having high color rendering properties and high brightness by being combined, and a light-emitting device using the phosphor. Furthermore, the present invention relates to an image display device and a lighting device that contain the light emitting device.

  A white light emitting device configured by combining a gallium nitride (GaN) blue light emitting diode as a semiconductor light emitting element and a phosphor as a wavelength conversion material has low power consumption and a long lifetime. Therefore, it has been attracting attention as a light source for image display devices and illumination devices.

In this light emitting device, the phosphor used therein absorbs the visible light in the blue region emitted by the GaN-based blue light emitting diode and emits yellow light. Therefore, the phosphor used with the blue light of the light emitting diode not absorbed by the phosphor White light emission can be obtained by mixing colors. As the phosphor, there is typically known a phosphor having yttrium / aluminum composite oxide (Y ₃ Al ₅ O ₁₂ ) as a base material and containing cerium (Ce) as a luminescent center ion in the base material. It has been. However, this phosphor is not easy to manufacture due to a high firing temperature and is not satisfactory in terms of temperature characteristics.

As an alternative yellow phosphor, the present inventors invented a phosphor having a basic structure of Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ (hereinafter abbreviated as “CSS phosphor”). (Patent document 1).
That is, the phosphor is characterized in that a compound having a garnet crystal structure represented by the following general formula is used as a base, and a luminescent center ion is contained in the base.
M ^{1 '} _a' M ^{2 '} _b' M ^{3 '} _c' O _{d '}
[Wherein M ^{1 ′} represents a divalent metal element, M ^{2 ′} represents a trivalent metal element, M ^{3 ′} represents a tetravalent metal element, and a _′ represents 2.7 to 3.3, b ′. 1.8 to 2.2, c ′ is 2.7 to 3.3, and d ′ is a number in the range of 11.0 to 13.0. ]
Patent Document 1 discloses Ca as a divalent metal element M ^{1 ′} , and further discloses a phosphor in which a part of Ca is substituted with Mg, Zn or the like. This CSS phosphor emits light from green to yellow depending on the composition, and is a high-quality phosphor that can also be used as a green phosphor of a light emitting device combining a GaN-based blue light emitting diode, a green phosphor and a red phosphor. is there.
JP2003-64358A.

  According to the study by the present inventors, the phosphor disclosed in Patent Document 1 described above has a luminance as shown in [1] to [3] below when used as a light emitting device combined with a GaN-based blue light emitting diode. It was also found that the color rendering property was not satisfactory.

[1] Since the emission spectrum of the CSS phosphor does not match the standard relative luminous sensitivity curve (“Phosphor Handbook”, published by Ohm Co., Ltd., page 422), the luminance of the CSS phosphor does not exceed the luminous efficiency. It has the problem of being low. [2] When a light emitting device containing a CSS phosphor is used as a backlight of a liquid crystal display, the emission peak wavelength of the CSS phosphor is in a wavelength region where the green color transmittance of a conventional color filter for liquid crystal displays is high. Since they do not match, the brightness as a liquid crystal display tends to decrease. [3] When a light emitting device containing a CSS phosphor is used as illumination, energy efficiency tends to decrease because the ratio of blue-green light (510 nm or less) with low visibility is large. Yes, color rendering is not satisfactory.

  The present invention has been made in view of the above-described problems, and uses a phosphor that emits light from green to yellow, which has a high luminance and color rendering properties, and can provide a high-luminance light-emitting device, and the phosphor. It is an object of the present invention to provide a light emitting device, and an image display device and an illumination device including the light emitting device.

As a result of intensive studies to solve the above problems, the present inventors have found that the shape and peak wavelength of the emission spectrum can be changed by limiting Mg to a specific range in the matrix composition of the CSS phosphor. The headline, the present invention has been reached.
That is, the present invention comprises the following gist.

(1) A phosphor comprising a compound represented by the following general formula (I) containing a compound having a garnet structure as a matrix and containing a metal element of a luminescent center ion in the matrix.
M ¹ _a M ² _b X _c M ³ _d M ⁴ ₃ O _e (I)
[In formula (I), M ¹ is Mg and / or Zn , Mg accounts for 50 mol% or more of M ¹ , M ² is a divalent metal element excluding Mg and Zn , and Ca is accounted for more than 50 mol% of M ^2, X is a metal element of the luminescent center ion Ce occupies at least 50 mole% of X, M ³ is a trivalent metal element excluding X, 50 Sc is of M ³ accounted for more than mole%, M ⁴ represents a Si respectively, a, b, c, d, and e are numbers satisfying the following formulas, respectively.
0.001 ≦ a ≦ 0.5
2.5 ≦ b ≦ 3.3
0.005 ≦ c ≦ 0.5
1.5 ≦ d ≦ 2.2
e = {(a + b) × 2 + (c + d) × 3 + 12} / 2]
(2) In the general formula (I), 0.001 ≦ a ≦ 0.3 (1
).
(3) The phosphor according to (1) or (2), wherein 0.02 ≦ c ≦ 0.1 in the general formula (I).
(4) In the general formula (I), M ² is at least one divalent metal element selected from the group consisting of Ca, Sr and Ba , and Ca accounts for 50 mol% or more of M ² The phosphor according to any one of (1) to (3), wherein
(5) In the general formula (I), M ³ is Al, Sc, Ga, Y, In, La, Gd and Lu.
At least one trivalent metal element selected from the group consisting of Sc and 50 mol% or more of M ³ , characterized in that any one of (1) to (4) Phosphor. ( 6 ) In the general formula (I), the metal element X of the luminescent center ion other than Ce is Mn, Fe,
The phosphor according to any one of (1) to ( 5 ), wherein the phosphor is at least one metal element selected from Pr, Nd, Sm, Eu, Gb, Tb, and Tm.
( 7 ) The phosphor according to any one of (1) to ( 6 ), wherein in the general formula (I), M ¹ is Mg.
( 8 ) The phosphor according to any one of (1) to ( 7 ), wherein in the general formula (I), X is Ce.
( 9 ) In general formula (I), X is Ce, M ¹ is Mg, M ² is Ca, M ³ is Sc, and M ⁴ is Si.
The phosphor according to any one of (1) to (3), wherein
( 10 ) The phosphor according to any one of (1) to ( 9 ), wherein the median diameter of the phosphor is 5 μm to 30 μm.
(1 1 ) At least a light source that emits light in a range from ultraviolet light to visible light, and a phosphor that converts at least a part of light from the light source and emits light in a longer wavelength region than the light from the light source A light emitting device having one or more types, wherein the phosphor includes the phosphor according to any one of (1) to ( 10 ).
(1 2 ) The light-emitting device according to (1 1 ), which emits white light.
(1 3 ) An image display device comprising the light-emitting device according to (1 1 ) or (1 2 ). (1 4 ) A lighting device including the light-emitting device according to (1 1 ) or (1 2 ).

  According to the present invention, it is possible to provide a phosphor that emits light from green to yellow, which has a high luminance and color rendering properties and can provide a light-emitting device with high luminance. Furthermore, by using the phosphor of the present invention, it is possible to provide an image display device and an illumination device with high color rendering properties and high luminance.

Hereinafter, although an embodiment of the present invention is described in detail, the present invention is not limited to the following embodiment. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
The relationship between the color name and the chromaticity coordinates in the specification is all based on the JIS standard (JISZ8110).

[Phosphor]
The phosphor of the present invention comprises a compound represented by the following general formula (I) containing a metal element mainly composed of cerium (Ce) as a luminescent center ion in a matrix having a garnet structure compound. It is characterized by.
M ¹ _a M ² _b X _c M ³ _d M ⁴ ₃ O _e (I)
[In the formula (I), M ¹ is Mg and / or Zn, M ² is a divalent metal element excluding Mg and Zn,
X represents a metal element of a luminescent center ion mainly composed of Ce, M ³ represents a trivalent metal element excluding X, M ⁴ represents a tetravalent metal element, and a, b, c, d, and e are Each number satisfies the following formula.
0.001 ≦ a ≦ 0.5
2.5 ≦ b ≦ 3.3
0.005 ≦ c ≦ 0.5
1.5 ≦ d ≦ 2.2
e = {(a + b) × 2 + (c + d) × 3 + 12} / 2]

Here, in the general formula (I), as M ¹ representing Mg and / or Zn, Mg preferably occupies 50 mol% or more of M ¹ , and particularly preferably 100 mol%.

In the general formula (I), M ² representing a divalent metal element excluding Mg and Zn is preferably at least one selected from the group consisting of Ca, Sr, and Ba. Furthermore, Ca preferably accounts for 50 mol% or more of M ² , and particularly preferably accounts for 100 mol%.

In the general formula (I), M ³ representing a trivalent metal element excluding the metal element X of the luminescent center ion is a group consisting of Al, Sc, Ga, Y, In, La, Gd, and Lu. Is preferably at least one selected from the group consisting of Al, Sc, Y, and Lu, and more preferably at least one selected from the group consisting of Al, Sc, Y, and Lu. Furthermore, Sc preferably occupies 50 mol% or more of M ³ , the remainder is preferably Y or Lu, and Sc preferably occupies 100 mol% of M ³ .

In the general formula (I), M ⁴ representing a tetravalent metal element includes Si, Ti,
It is preferably at least one selected from the group consisting of Ge, Zr, Sn, and Hf, and more preferably at least one selected from the group consisting of Si, Ge, and Sn. Further, Si preferably accounts for 50 mol% or more of M ⁴ , and particularly preferably accounts for 100 mol%.

Further, in the general formula (I), X representing the metal element of the luminescent center ion mainly composed of Ce preferably occupies 50 mol% or more of X, more preferably 70 mol% or more. Preferably, it occupies 90 mol% or more, more preferably 100 mol%.
Ce ³⁺ ions absorb visible light in a wavelength region of 400 nm to 500 nm and emit green, yellow-green, yellow, and orange light. The phosphor of the present invention has an addition amount of Ce and addition of M ¹ ions. By adjusting both the amounts, the emission color can be adjusted to the desired color.
Examples of the metal element of the luminescent center ion other than Ce include Mn, Fe, Pr, Nd, Sm, Eu, Gb, Tb, and Tm. For example, by containing Pr, light emitted from Pr ³⁺ ions appears in the vicinity of 620 nm together with light emitted from Ce ³⁺ ions, so that the red component increases and the emission color of the phosphor is adjusted closer to red. And color rendering can be improved.

The garnet structure is represented by the general formula A ₃ B ₂ C ₃ O ₁₂ [A is a divalent metal element, B is a trivalent metal element, and C is a tetravalent metal element]. _This is a body-centered cubic crystal structure represented by I _a3d . A, B, and C ions are located at 12, 8, and tetrahedrally coordinated sites, respectively, and oxygen atoms are coordinated by 8, 6, and 4, respectively, and the natural mineral garnet has. It is the same structure as the crystal structure. In the phosphor represented by the general formula (I), the divalent metal element M ² mainly composed of Ca occupies the A ion position in the general formula A ₃ B ₂ C ₃ O ₁₂ , and the B ion position is composed mainly of Sc. The trivalent metal element M ³ occupies the C ion position and the Si-based tetravalent metal element M ⁴ occupies the Ce-based metal element X as the luminescent center ion, and includes Mg and / or Zn 2. It contains a valent metal element.

In the general formula (I), a must be 0.001 or more;
It is preferably 003 or more, more preferably 0.01 or more, and particularly preferably 0.03 or more. Further, a must be 0.5 or less, preferably 0.3 or less, particularly preferably 0.1 or less. If a is less than 0.001, it is difficult to increase the luminance when the phosphor is used in a light emitting device. On the other hand, if it exceeds 0.5, the emission intensity of the phosphor is remarkably reduced, and a high-luminance light-emitting device cannot be obtained.

In the general formula (I), b is 2.5 to 3.3, preferably 2.6 to 3.2.
More preferably, it is 2.7 to 3.1. In the general formula A ₃ B ₂ C ₃ O ₁₂ , the coefficient of A ion is 3, and if M ¹ of Mg or Zn in the present invention occupies the A ion position, b is close to “3-a”. Take. Moreover, the position occupied in the crystal of Ce as the main luminescent center ion is not clear, but since the ionic radius of the Ce ³⁺ ion is very close to the ionic radius of the Ca ²⁺ ion, Ce has the position of the A ion. If it occupies, b will take the value close | similar to "3-ac". On the other hand, when M ¹ of Mg or Zn and a part of M ² of the divalent metal element are present at positions other than the A ion position, or conversely, M ^{3 of the} trivalent metal element or tetravalent metal. There may be a case where a part of the element M ⁴ or a monovalent metal element added as a flux or the like to be described later is present at the A ion position. It is also conceivable that Ce as the main luminescent center ion exists at the B ion position. Considering these, if b is 2.5 to 3.3, a desired phosphor can be obtained.

In the general formula (I), it is essential that c is 0.005 or more.
It is preferably 01 or more, more preferably 0.02 or more, further preferably 0.03 or more, and most preferably 0.05 or more. Further, it is essential that c is 0.5 or less, preferably 0.3 or less, more preferably 0.2 or less, and particularly preferably 0.1 or less. In both cases where c is less than 0.001 and exceeds 0.5, it is difficult to increase the luminance when the phosphor is used in a light emitting device.

In the general formula (I), d is 1.5 to 2.2, preferably 1.7 to 2.0.
It is. The coefficient of B ions in the general formula A ₃ B ₂ C ₃ O ₁₂ is 2. If the metal element X of the luminescent center ion in the present invention occupies the B ion position, d takes a value close to “2-c”. Similarly to the case of the coefficient b, considering that a metal element other than the trivalent metal element is present at the B ion position, a desired phosphor can be obtained if d is 1.5 to 2.2. .

In the general formula (I), e indicating the coordination number of the oxygen atom is difficult to measure accurately. Therefore, it is assumed that the oxygen ion has a charge of −2, and the valences of M ¹ , M ² , X, M ³ , and M ⁴ constituting the cation and the coefficients a, b, c, It was decided to calculate from d and 3 so that the charge balance was maintained. That is, e = {(a + b) × 2 + (c + d) × 3 + 12} / 2.
Among the phosphors represented by the general formula (I),
Mg _0.03 Ca _2.97 Ce _0.03 Sc _1.97 Si ₃ O ₁₂ ,
Mg _0.06 Ca _2.94 Ce _0.03 Sc _1.94 Si ₃ O ₁₂ ,
Mg _0.03 Ca _2.97 Ce _0.03 Sc _1.97 Si ₃ O ₁₂ ,
Mg _0.03 Ca _2.94 Ce _0.06 Sc _1.97 Si ₃ O ₁₂ ,
Mg _0.03 Ca _2.9 Ce _0.1 Sc _1.97 Si ₃ O ₁₂ ,
Mg _0.06 Si ₃ O ₁₂ Ca _2.97 Ce _0.03 Sc _1.94 Si ₃ O ₁₂ ,
Mg _0.06 Ca _2.94 Ce _0.06 Sc _1.94 Si ₃ O ₁₂ ,
Mg _0.06 Ca _2.9 Ce _0.1 Sc _1.94 Si ₃ O ₁₂ ,
Mg _0.1 Ca _2.97 Ce _0.03 Sc _1.9 Si ₃ O ₁₂ ,
Mg _0.1 Ca _2.94 Ce _0.06 Sc _1.9 Si ₃ O ₁₂ ,
Mg _0.1 Ca _2.9 Ce _0.1 Sc _1.9 Si ₃ O ₁₂
A phosphor that can be expressed by, for example, is preferable. Among these,
Mg _0.03 Ca _2.97 Ce _0.03 Sc _1.97 O ₁₂
Mg _0.06 Ca _2.94 Ce _0.03 Sc _1.94 O ₁₂
A phosphor represented by

The phosphor of the present invention is preferably composed of a compound containing a metal element mainly composed of Ce as a luminescent center ion in a base crystal having a garnet structure, but when the composition ratio of the compound as a production raw material is slightly changed In some cases, crystals other than the garnet-based host compound may coexist. In that case, the coexistence of the phosphors is allowed as long as the amount of the phosphors is not impaired. Examples of such coexisting compounds include Sc ₂ O ₃ as an unreacted raw material, and by-products such as Ca ₂ MgSi ₂ O ₇ and Ce _4.67 (SiO ₄ ) ₃ O.

In the phosphor of the present invention, M ¹ which is Mg and / or Zn, and M ² and Ce which are divalent metal elements excluding Mg and Zn are within the range not impairing the effects of the present invention. It may contain an element other than the above-described M ³ which is a trivalent metal element, M ⁴ which is a tetravalent metal element, and a metal element X mainly composed of Ce as an emission center ion. For example, it is derived from an alkali halide or the like added as a crystal growth accelerator (flux) during the production of the phosphor. Examples thereof include alkali metal elements such as Li, Na, K, Rb, and Cs, or other metal elements such as Nb, Ta, Sb, and Bi, and halogen elements. However, since these metal elements and halogen elements are different from their ionic radii and / or charges, there is a possibility that the environment of Ce ions as luminescent ions may be changed and the emission wavelength and spectral width may be changed. It is necessary to adjust the content in these phosphors so that the characteristics of the body do not deviate from the desired range.

In the phosphor of the present invention, as described above, the divalent metal element M ² mainly composed of Ca occupies the A ion position in the general formula A ₃ B ₂ C ₃ O _{12 having} a garnet structure, and the B ion position is composed mainly of Sc. The trivalent metal element M ³ occupies the C ion position, the Si-based tetravalent metal element M ⁴ occupies the Ce-based metal element as the luminescent center ion, and further contains Mg and / or Zn 2. It contains a valent metal element. Here, although the divalent ions of Mg and Zn are expected to exist at the A ion position, the ion radius of Mg and Zn is the ion of Ca as the main component of the divalent metal element M ² occupying the A ion position. Since it is closer to the ionic radius of Sc as the main component of the trivalent metal element M ³ occupying the B ion position than the radius, most of Mg and Zn are considered to exist at the B ion position. The ionic radius of Ce as the main component of the metal element X of the luminescent center ion is a divalent metal occupying the A ion position rather than the ionic radius of Sc as the main component of the trivalent metal element M ³ occupying the B ion position. Since it is close to the ionic radius of Ca as the main component of the element M ² , most of Ce is considered to exist at the A ion position. Thus, Ce is present at the A ion position occupied by Ca as the main component of the divalent metal element M ² , and Mg or Zn is present at the B ion position occupied by Sc as the main component of the trivalent metal element M ^3. It is considered that the charge balance is maintained by the existence. That is, the excess of positive charge caused by the presence of trivalent Ce at the divalent Ca position is offset by the lack of positive charge due to the presence of divalent Mg or Zn at the trivalent Sc position. The balance of charge is maintained as a whole crystal.
When the content of Ce in the crystal was examined, it was found that the content of Ce in the crystal tends to increase by adding Mg. This indicates that Mg and Ce are both present in the crystal according to the above mechanism. In other words, it can be said that the addition of Mg promotes the solid solution at the Ca position in the Ce crystal. The long wavelength shift of the emission spectrum due to the addition of Mg is derived from the change in the crystal field due to the presence of Mg as described above, and at the same time, the Ce contained in the crystal increases. This is probably because the energy level of Ce ions is shifted by the interaction between Ce and Ce.

The phosphor of the present invention contains Mg or Zn divalent ions, and at the same time, the Ce content increases, so that the coordination environment of Ce ³⁺ ions, which are luminescent ions, is changed by some mechanism. It is considered that the emission wavelength is shifted to the longer wavelength side due to the decrease in the energy of the 5d level, which is the excited state of Ce ³⁺ ions. Even if a long wavelength shift of the emission wavelength occurs, the increase of the emission peak intensity is not so large, and when the shift width is increased, the emission peak intensity is decreased. However, since the long wavelength shift of the emission wavelength increases the overlap with the standard relative luminous sensitivity curve, the luminance can be greatly improved by setting the shift width so that the peak intensity does not decrease so much.

[Phosphor production method]
The phosphor of the present invention is a compound of M ¹ source that is Mg and / or Zn in the general formula (I), a compound of M ² source that is a divalent metal element, and M ³ that is a trivalent metal element. Produced by reacting a pulverized mixture prepared from a source compound, a tetravalent metal element M ⁴ source compound, and a raw material compound of a metal element source such as Ce as a luminescent center ion by heat treatment The

The pulverized mixture can be prepared by various methods such as the following dry methods and wet methods.
(1) In the dry method, the above compounds are pulverized using a dry pulverizer such as a hammer mill, roll mill, ball mill, jet mill, etc., and then mixed by a blender such as a ribbon blender, V-type blender or Henschel mixer. Alternatively, after mixing the above compounds, the mixture is pulverized using a dry pulverizer.
(2) In the wet method, the above compound is added to a medium such as water and pulverized and mixed using a wet pulverizer such as a medium stirring pulverizer, or the above compound is pulverized with a dry pulverizer. Then, the slurry prepared by adding and mixing in a medium such as water is dried by spray drying or the like.
Among the methods for preparing the pulverized mixture, the wet source method using a liquid medium is particularly preferable because the element source compound of the luminescent center ion needs to uniformly mix and disperse a small amount of compound throughout. Also, other element source compounds are preferably wet methods from the viewpoint of obtaining uniform mixing throughout.

In the mixing, for the purpose of promoting the crystal growth of the phosphor and controlling the particle size, a compound containing a metal element or an anion that is not included in the general formula (I), so-called flux is added. May be. Examples of the flux include alkali metal halides, ammonium halides, various borate compounds, alkaline earth metal halides, alkali metal carbonates, and various phosphates. Specific examples of the compounds are LiF, LiCl, NaF, NaCl, KCl, KF, NH ₄ F, NH ₄ Cl, Li ₂ CO _3, Na ₂ CO _3, Li ₃ PO ₄ , Na ₃ PO _4, Na ₂ HPO _4, NaHPO _4, K ₃ PO _4, K ₂ HPO _4, KH ₂ PO _4, H ₃ BO _3, B ₂ O _3, Na ₂ B ₄ O ₇ , MgF _2, CaF _2, SrF _2, BaF _2, MgCl _2, CaCl _2, SrCl _2, BaCl _2, AlF ₃ , YF _{3 and the} like. Of these, fluorides, chlorides, and phosphates are preferable for controlling the particle size and improving reactivity, and CaCl ₂ is particularly preferable.
The median diameter D ₅₀ of the phosphor of the present invention is usually 2 μm to ₅₀ μm, preferably 5 μm to 30 μm, more preferably 10 μm to 25 μm, and most preferably 15 μm to 20 μm. If the median diameter is too small, the absorption efficiency of the excitation light is reduced, which may reduce the brightness of the phosphor. If the median diameter is too large, the phosphor will settle in the resin, so that the LED brightness is reduced. May be lowered.

  The firing is preferably performed using a heat-resistant container such as alumina, quartz crucible, tray, or a metal container such as platinum or tantalum. If necessary, a container coated with boron nitride can also be used. Regarding the firing temperature, firing can usually be carried out in the range of 1000 ° C to 1600 ° C, preferably 1200 ° C to 1500 ° C, and particularly preferably 1400 ° C to 1500 ° C. The firing atmosphere is usually a single or mixed atmosphere of gases such as air, oxygen, carbon monoxide, carbon dioxide, nitrogen, hydrogen, and argon. The heating time is 10 minutes to 24 hours, preferably 30 minutes to 12 hours, and may be performed a plurality of times as necessary. At that time, after the first heating, pulverization, dispersion and the like may be performed again.

  After the heat treatment of the phosphor, post-treatment such as washing, dispersion, classification, drying, and surface coating is performed as necessary. The cleaning treatment is performed using water, an inorganic acid such as hydrochloric acid, nitric acid, and acetic acid, an aqueous solution of ammonia, an aqueous solution of sodium hydroxide, and the like. The dispersion process is performed using a ball mill, a jet mill, a hammer mill, or the like. In addition, the classification treatment is performed by wet classification such as chickenpox treatment, dry classification using an airflow disperser, or a combination thereof. Surface coating is a method in which fine particles such as silica and alumina are deposited on the surface of the phosphor particles by wet using these sols, and calcium phosphate is deposited on the surface of the phosphor particles by the reaction between ammonium phosphate and a calcium compound. The method of making it take is taken.

  Further, after these post treatments, reheating can be performed at a temperature lower than the heat treatment temperature for the purpose of reducing crystal defects of the phosphor. The heating atmosphere at that time is preferably a reducing atmosphere such as nitrogen, argon, nitrogen containing a small amount of hydrogen, or nitrogen containing a small amount of carbon monoxide. Further, prior to heating in the reducing atmosphere, it is more preferable to heat at a temperature of 800 ° C. to 1300 ° C. in an oxidizing atmosphere such as air.

M ¹ which is Mg and / or Zn in the general formula (I) used in the production of the present invention
Compound of source, compound of M ² source that is divalent metal element, compound of M ³ source that is trivalent metal element, compound of M ⁴ source of tetravalent metal element, and Ce as luminescent center ion As raw material compounds of the metal element X source such as M ¹ , M ² , M ³ , and M ⁴ , and oxides, hydroxides, carbonates, nitrates, sulfates, oxalates of the respective metal elements of X , Carboxylates, halides and the like. Of these, the reactivity to the composite oxide and the non-generation of NO _x , SO _x, etc. during firing are selected.

The Mg source compound in M ¹ is its Mg and / or Zn, for _{example, 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 , MgF _2, etc. Examples of Zn source compounds include ZnO, Zn ( OH) ₂ , ZnCO ₃ , Zn (NO ₃ ) ₂ , Zn (OCO) ₂ , Zn (OCOCH ₃ ) ₂ , ZnCl ₂ , ZnF _{2 and the} like.

Regarding Ca, Sr, and Ba that are preferable as M ² that is a divalent metal element, examples of the Ca source compound 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 , CaF _2, etc., and Sr source compounds include, for example, SrO Sr (OH) ₂ , SrCO ₃ , Sr (NO ₃ ) ₂ , SrSO ₄ , Sr (OCO) ₂ .H ₂ O, Sr (OCOCH ₃ ) ₂ .4H ₂ O, SrCl ₂ .6H ₂ O, etc. Examples of the Ba source compound include BaO, Ba (OH) ₂ , BaCO ₃ , Ba (NO ₃ ) ₂ , BaSO ₄ , Ba (OCO) ₂ .2H ₂ O, Ba (OCOCH ₃ ) ₂ .H _2. O, BaCl ₂ · 2H ₂ O, etc. may be mentioned are

Regarding Al, Sc, Y, and Lu that are preferable as M ³ that is a trivalent metal element, examples of the Al source compound include Al ₂ O ₃ , Al (OH) ₃ , AlOOH, Al (NO _3). ) ₃ · 9H ₂ O, Al ₂ (SO ₄ ) ₃ , AlCl ₃ , AlF _{3 and the} like, and examples of the Sc source compound 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 , ScF _3, etc., and Y source compounds include, for example, 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 , YCl ₃ , YF ₃ etc. the Lu source compound, for _{example, Lu 2 O 3, Lu 2} (SO 4) 3, LuCl 3, LuF 3 and the like, respectively ani It is.

For Si, Ge, and Sn that are preferable as M ³ which is a tetravalent metal element, examples of the Si source compound include SiO ₂ , H ₄ SiO ₄ , Si (OC ₂ H ₅ ) ₄ , and CH _3. Si (OCH ₃ ) ₃ , CH ₃ Si (OC ₂ H ₅ ) ₃ , Si (OCOCH ₃ ) _{4 and the} like, and examples of the Ge source compound include GeO ₂ , Ge (OH) ₄ , Ge (OCOCH _3). ) ₄ , GeCl _{4 and the} like, and examples of the Sn source compound include SnO ₂ , SnO ₂ .nH ₂ O, Sn (NO ₃ ) ₄ , Sn (OCOCH ₃ ) ₄ , and SnCl _4. .

Further, examples of the Ce source compound mainly used as the metal element of the emission center ion include Ce ₂ O ₃ , CeO ₂ , Ce (OH) ₃ , Ce (OH) ₄ , Ce ₂ (CO ₃ ) ₃ , and 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 , CeF _{3 and the} like.
Any of these raw material compounds may be used alone or in combination of two or more.

[Combination of phosphor]
As the phosphor in the light emitting device of the present invention, the phosphor of the present invention may be used alone, or two or more kinds may be used in any combination and ratio. In addition to the phosphor of the present invention, a phosphor that emits light in red, orange, yellow, or the like is used in combination, whereby a light emitting device with higher color rendering properties can be obtained. In this case, the phosphor used in combination is preferably a phosphor that emits light in a wavelength region of 580 to 780 nm. For example, when divalent Eu is used as a luminescent center ion, sulfide phosphors such as CaS: Eu ²⁺ and SrS: Eu ²⁺ , Ca ₂ Si ₅ N ₈ : Eu ²⁺ , Sr ₂ Si ₅ N _{^{8: Eu 2+, Ba 2 Si}} 5 N 8: Eu 2+, CaAlSiN 3: Eu 2+, SrAlSiN 3: Eu 2+, (Ca x '', Sr 1-x '') AlSiN 3: Eu 2+ (0 ≦ x _'' ≦
1) nitride phosphor such as LaSi ₃ N ₅ : Eu ²⁺ , and Sr ₂ Si ₃ Al ₂ N ₆ O ₂ : Eu ²⁺ , Cax _″ (Si _{y ″} , Al _{1-y ”} ) ₁₂ (O _{z ″} , N _{1-z ″} ) ₁₆ : Eu ²⁺ (0 ≦ x _″ ≦ 1,0)
An oxynitride phosphor such as ≦ y _″ ≦ 1, 0 ≦ z _″ ≦ 1) is preferable. In addition, when trivalent Eu is used as the luminescent center ion, oxysulfide phosphors such as La ₂ O ₂ S: Eu ³⁺ , Y ₂ O ₂ S: Eu ³⁺ , and trivalent Eu are used. Preference is given to coordination compound phosphors coordinated with acetylacetone, thenoyltrifluoroacetone and the like. In addition, in the case of using tetravalent Mn as the luminescent center ion, 3.5MgO · 0.5MgF ₂ · GeO ₂ : Mn ⁴⁺ or the like is preferable. Among these, sulfide-based phosphors and nitride-based phosphors having Eu ²⁺ as the luminescent center ion are particularly preferable because of high emission intensity. In particular, preferable examples of the red phosphor include, for example, CaAlSiN ₃ : Eu ²⁺ , (Sr, Ca) AlSiN ₃ : Eu ²⁺ , M ₂ Si ₅ N ₈ as described in the WO2005 / 052087Al pamphlet: Eu ²⁺ (M is at least one selected from the group consisting of Ca, Si and Ba), Sr ₂ Si ₃ Al ₂ N ₆ O ₂ : Eu ²⁺ , LaSi ₃ N ₅ : Eu ²⁺ Nitride-based or oxynitride-based phosphors such as the above are preferable.

[Light Emitting Element / Surface Lighting Equipment]
A light-emitting device according to the present invention is a light-emitting device having at least a light source such as a semiconductor light-emitting element and a phosphor that emits visible light having a longer wavelength by absorbing light in a range from ultraviolet light to visible light emitted from the light source. is there. It is a light emitting device with high color rendering properties, and is suitable as a light source for image display devices such as a color liquid crystal display and lighting devices such as surface light emission.
The light emitting device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of a light-emitting device composed of the phosphor of the present invention as a wavelength conversion material and a light source. FIG. 2 is a schematic cross-sectional view showing an embodiment of a surface emitting illumination device incorporating the light emitting device shown in FIG. 1 and 2, 1 is a light emitting device, 2 is a mount lead, 3 is an inner lead, 4 is a light source, 5 is a phosphor-containing resin part, 6 is a conductive wire, 7 is a molding member, and 8 is a surface emitting light. An illuminating device, 9 is a diffusion plate, and 10 is a holding case.

The light-emitting device 1 of the present invention has a general bullet shape, for example, as shown in FIG. A light source 4 made of a GaN blue light emitting diode or the like is bonded to the upper cup of the mount lead 2. The phosphor-containing resin part is prepared by mixing and dispersing the phosphor of the present invention and another phosphor (for example, red light-emitting phosphor) in a binder such as an epoxy resin, an acrylic resin, or a silicone resin and pouring it into the cup. 5 is formed. The light source 4 is covered and fixed with the phosphor-containing resin portion 5. On the other hand, the light source 4 and the mount lead 2, and the light source 4 and the inner lead 3 are electrically connected by conductive wires 6 and 6, respectively, and are entirely covered and protected by a mold member 7 made of epoxy resin or the like.

  Moreover, the surface emitting illumination device 8 incorporating this light-emitting device 1 is shown in FIG. A large number of light emitting devices 1 are provided on the bottom surface of a rectangular holding case 10 whose inner surface is light-opaque, such as a white smooth surface, and a power source and circuits for driving the light emitting device 1 are provided outside (not shown). ) And arrange. In order to make the light emission uniform, a diffusion plate 9 such as an acrylic plate made of milky white is fixed to a portion corresponding to the lid portion of the holding case 10.

  Then, the surface emitting illumination device 8 is driven to apply blue voltage to the light source 4 of the light emitting device 1 to emit blue light or the like. A part of the emitted light is absorbed in the phosphor-containing resin part 5 by the phosphor of the present invention, which is a wavelength conversion material, and another phosphor added as necessary, and converted into light having a longer wavelength. Color rendering is high due to color mixing with blue light or the like that has not been absorbed in the light, and light emission with high luminance can be obtained. This light passes through the diffusion plate 9 and is emitted upward in the drawing, and illumination light with uniform brightness is obtained within the surface of the diffusion plate 9 of the holding case 10.

  Here, the light source 4 is a light source that emits excitation light of the phosphor contained in the phosphor-containing resin portion 5, and is also a light source that emits light as one component of light emitted from the light emitting device 1. is there. That is, a part of the light emitted from the light source 4 is absorbed as excitation light by the luminescent substance in the phosphor-containing resin portion 5, and another part is emitted from the light emitting device 1. Yes.

The type of the light source 4 is arbitrary, and an appropriate one can be selected according to the application and configuration of the display device. However, it is usually necessary to use a light source that has no bias in light distribution and emits light widely. preferable.
For example, a light-emitting diode (hereinafter referred to as “LED” as appropriate), an edge-emitting or surface-emitting laser diode, an electroluminescence element, and the like can be given, but an inexpensive LED is usually preferable. Specific examples of the LED include an LED using an InGaN-based, GaAlN-based, InGaAlN-based, ZnSeS-based semiconductor, or the like crystal-grown on a substrate such as silicon carbide, sapphire, or gallium nitride by a method such as MOCVD. .

Moreover, when using LED as the light source 4 in this way, there is no restriction | limiting in the shape, but in order to improve the extraction efficiency of light, it is preferable to make the side surface into a taper shape.
Furthermore, the material of the LED package is also arbitrary, and for example, ceramics, PPA (polyphthalamide), or the like can be used as appropriate. However, from the viewpoint of improving color reproducibility, the color of the package is preferably white or silver. From the viewpoint of increasing the light emission efficiency of the light emitting device 1, it is preferable that the reflectance of light is increased.

  Moreover, when attaching the light source 4 to the mount lead 2, the specific method is arbitrary, For example, it can attach using solder | pewter. The type of solder is arbitrary, but, for example, AuSn, AgSn, or the like can be used. Moreover, when using solder, it is also possible to supply electric power from the electrode formed on the mount lead 2 through the solder. In particular, when a large current type LED or laser diode, for which heat dissipation is important, is used as the light source 4, it is effective to use solder for installing the light source 4 because the solder exhibits excellent heat dissipation.

  Further, when the light source 4 is attached to the mount lead 2 by means other than solder, for example, an adhesive such as an epoxy resin, an imide resin, or an acrylic resin may be used. In this case, by using a paste in which conductive fillers such as silver particles and carbon particles are mixed with the adhesive, the adhesive can be energized to supply power to the light source as in the case of using solder. It is also possible to make it. Furthermore, it is preferable to mix these conductive fillers because heat dissipation is improved.

Furthermore, the power supply method to the light source 4 is also arbitrary. In addition to energizing the solder and adhesive described above, the light source 4 and the electrode may be connected by wire bonding to supply power. At this time, the wire used is not limited, and the material, dimensions, etc. are arbitrary. For example, metals such as gold and aluminum can be used as the wire material. Moreover, although the thickness of the wire can be normally 20 micrometers-40 micrometers, a wire is not limited to this.
Another example of a method for supplying power to the light source is a method for supplying power to the light source by flip chip mounting using bumps.

One light source may be used alone, or two or more light sources may be used in combination. Furthermore, the light source 4 may be used alone or in combination of two or more.
Moreover, the light source 4 may share the one light source 4 with the fluorescent substance containing resin part 5 containing two or more types of fluorescent substance. It is also possible to produce two or more phosphor-containing resin parts 5 and provide the light source 4 for each.

The light source 4 in the light emitting device 1 is not particularly limited as long as it emits light in the range from ultraviolet light to visible light, but preferably emits light in the wavelength region of 380 nm to 550 nm. . Among these, 400 nm or more is more preferable, and 420 nm or more is particularly preferable. Moreover, 520 nm or less is still more preferable, and 500 nm or less is especially preferable. Among these, when a light source that emits light in a wavelength region of 430 nm to 480 nm is used, a light emitting device having particularly high color rendering properties can be obtained.
When the phosphor of the present invention is used alone for the phosphor-containing resin part 5, a light yellow-green, light green, or light blue-green light emitting device can be obtained. Further, by combining the phosphor of the present invention with an arbitrary red phosphor, a white light emitting device having an arbitrary color temperature can be configured.
For example, the phosphor of the present invention and the red phosphor are used as the phosphor contained in the phosphor-containing resin portion 5. The phosphor-containing resin part 5 absorbs a part of light in the ultraviolet to blue region emitted by the light source 4 and emits light in the green region and the red region. Using this phosphor-containing resin portion 5 in the light emitting device 1 and / or the surface emitting illumination device 8 having the above-described configuration, the blue light emitted from the light source 4 and the green light and red light of the phosphor are produced. A light emitting device 1 and / or a surface emitting illumination device 8 that emits white light with high color rendering properties when mixed is provided. The light-emitting device and / or the surface-emitting illumination device can emit light in, for example, a light bulb color, a daylight white color, and a daylight color according to JIS standards. Here, the light bulb color, the daylight white color, and the daylight color indicate light emission in the chromaticity range defined as the light source color of the fluorescent lamp defined in JIS Z9112.

  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.

Example 1
Mg (OH) ₂ .3MgCO ₃ .3H ₂ O as M ¹ source compound; 0.0006 mol as Mg, CaCO ₃ as 0.02 mol as M ² source compound, Sc ₂ O ₃ as M ³ source compound; 0097 mol, SiO ₂ as M ⁴ source compound; 0.03 mol, and Ce (NO ₃ ) ₃ (aqueous solution) as X source compound; 0.0003 mol of each raw material together with a small amount of ethanol in an agate mortar, After mixing well, it was dried. Next, the dried raw material mixture was wrapped in platinum foil, and baked by heating at 1400 ° C. for 3 hours in the atmosphere while circulating nitrogen gas containing 4% by weight of hydrogen. Subsequently, the phosphor was manufactured by pulverization and classification.

The obtained phosphor was analyzed by powder X-ray diffraction. The measurement was performed using a powder X-ray diffractometer X'Pert MPD manufactured by Spectris. The X-ray source was Cu-Kα ray, and the voltage and current were 45 KV and 40 mA, respectively. As a result, it was confirmed that the compound had a garnet crystal structure. FIG. 9 shows a powder X-ray diffraction pattern of this phosphor.
Next, the emission spectrum of this phosphor was measured by the following method, and the results are shown in FIG. FIG. 3 also shows the specific visibility curve.

<Measurement of emission spectrum>
In a fluorescence measuring apparatus manufactured by JASCO Corporation, a 150 W xenon lamp was used as an excitation light source. The light from the xenon lamp was passed through a 10 cm diffraction grating spectrometer, and only the light having a wavelength of 455 nm was irradiated to the phosphor through the optical fiber. The light generated by the irradiation of the excitation light was dispersed by a 25 cm diffraction grating spectrometer, and the emission intensity of each wavelength of 300 nm to 800 nm was measured by a multichannel CCD detector “C7041” manufactured by Hamamatsu Photonics. Subsequently, an emission spectrum was obtained through signal processing such as sensitivity correction by a personal computer. The emission peak wavelength is shown in Table 1.

In addition, from the data in the wavelength region of 480 nm to 800 nm of the emission spectrum, JIS
The chromaticity coordinates x and y in the XYZ color system defined by Z8701 were calculated, and the results are shown in Table 1. Further, from the stimulus value Y in the XYZ color system calculated in accordance with JIS Z8724, the relative luminance with the stimulus value Y of the phosphor obtained in Comparative Example 1 described later as 100% is calculated, and the result is It is shown in Table 1. Furthermore, the relative emission peak intensity was calculated with the emission peak intensity of the phosphor obtained in Comparative Example 1 as 100%, and the results are shown in Table 1.

(Comparative Example 1)
Phosphor production raw materials were CaCO ₃ as an M ² source compound; 0.0297 mol, Sc ₂ O ₃ as an M ³ source compound; 0.01 mol, and SiO ₂ as an M ⁴ source compound; 0.03 mol, and X A phosphor was produced in the same manner as in Example 1 except that Ce (NO ₃ ) ₃ (aqueous solution) as a source compound; 0.0003 mol, and the firing temperature was 1500 ° C., and evaluated in the same manner. The results are shown in Table 1. The emission spectrum of this phosphor is shown in FIG. FIG. 5 also shows the specific visibility curve. When compared with the emission spectrum of the phosphor of Example 1 (FIG. 3), it can be seen that the emission spectrum of the phosphor of Comparative Example 1 has a small overlap with the specific luminous efficiency curve.

(Examples 2 to 13, Comparative Examples 2 and 3)
A phosphor was produced in the same manner as in Example 1 except that the phosphor production raw materials were mixed in the composition shown in Table 1 and the firing temperature was changed to the temperature shown in Table 1, and evaluated in the same manner. The results are shown in Table 1. The emission spectrum of the phosphor obtained in Example 7 is shown in FIG. 3 to 5, it can be seen that the overlap between the emission spectrum and the relative visibility curve increases in the order of Comparative Example 1, Example 1, and Example 7. When the overlap between the emission spectrum and the specific visibility curve increases, the phosphor has a high luminance relative to the relative emission peak intensity.

(Examples 14 and 15 and Comparative Example 4)
Except that the phosphor production raw materials were mixed in the composition shown in Table 1, after producing the phosphor by the procedure shown in Example 1, the phosphor was immersed in 1 mol / L hydrochloric acid and stirred for 12 hours. By leaving to stand, impurities soluble in hydrochloric acid were removed. The phosphor and the hydrochloric acid solution that did not dissolve were separated, and then washed with water (repeating the water, stirring, and then repeating the solid-liquid separation step). Subsequently, after drying and sieving, the phosphors of Examples 14 and 15 and Comparative Example 4 were obtained.
The median diameters of the phosphors of Examples 14 and 15 were measured with a laser diffraction particle size distribution analyzer (LA-300 manufactured by Horiba, Ltd.), and were 7.5 μm and 6.1 μm, respectively.

The composition of the phosphor obtained in Examples 14 and 15 and Comparative Example 4 was measured by the following method.
<Measurement of Ca, Sc, Si, Ce, Mg content>
The phosphor sample was melted with 30 times the amount of sodium carbonate, dissolved and diluted with dilute hydrochloric acid to obtain a measurement solution, and quantified by an inductively coupled plasma emission analysis (ICP-AES) method. The calibration curve solution was prepared using a commercially available standard solution so as to have the same salt concentration as the sample solution.

<Measurement of alkali metal content>
Add 50 times the amount of perchloric acid and hydrofluoric acid (HF) to the phosphor sample, heat and treat with white smoke, add hydrochloric acid, heat and dilute to obtain a measurement solution, and use the atomic absorption (AAS) method. Na was quantified by inductively coupled plasma optical emission spectrometry (ICP-AES). The calibration curve solution was prepared using a commercially available standard solution so as to have the same acid concentration as the sample solution.
From these measurement results, the composition ratio of silicon was set to 3, and the ratio of each component atom in the phosphor was determined. The results are shown in Table 2.
9 to 13 are powder X-ray diffraction patterns of the phosphors of the present invention obtained in Examples 1, 5, 7, 14, and 15. FIG.
The phosphors of Examples 1, 5, and 7 are JCPDS standard chart No. The diffraction line of the phosphor having a garnet structure corresponding to 72-1969 is detected as a main component, and Sc ₂ O ₃ (JCPDS No. 84-1880, 88-2159), CaSiO ₃ (JCPDS No. 3- 1068, 1-720), Ca ₂ MgSi ₂ O ₇ (JCPDS No. 79-2425), Ce _4.67 (SiO ₄ ) ₃ O (JCPDS No. 31-336), etc. A line was observed. The impurity phase was detected because this phosphor was not subjected to a cleaning process.
On the other hand, in the diffraction patterns of the phosphors of Examples 14 and 15 subjected to the acid cleaning treatment, only the diffraction lines derived from the garnet structure phosphor and the impurity phase Sc ₂ O ₃ were detected. Impurity phases other than Sc ₂ O ₃ were dissolved and removed by acid cleaning.

FIG. 6 is a graph in which all CIE chromaticity coordinates of Examples 1 to 15 and Comparative Example 1 are plotted. As shown in FIG. 6, it is plotted on almost one straight line. It can be seen that, due to the increase in the amount of Mg and the accompanying increase in the amount of Ce present in the crystal, x increases and y decreases, and the emission color increases redness.
FIG. 7 shows the relative luminance (indicated by black squares in FIG. 7) and the relative emission peak intensity (in FIG. 7, when the Ce composition ratio is 0.03 with respect to the shift of the emission peak wavelength due to the addition of Mg. It is the graph which showed simply the relationship of (shown by □) from the data of the Example. When the amount of Mg added is increased, the relative emission peak intensity decreases greatly after a slight improvement. On the other hand, the luminance is improved and then decreased, but all of the phosphors of the present example are higher than the luminance of the phosphor of Comparative Example 1 (relative luminance = 100). This is thought to be due to an increase in luminance due to an increase in overlap between the standard relative luminous sensitivity curve and the emission spectrum, and the effect compensates for a decrease in peak intensity. Further, the relative luminance (indicated by ● in FIG. 7) and the relative emission peak intensity (indicated by ○ in FIG. 7) of the phosphors obtained in Examples 12 and 13 are shown in FIG. Thus, it can be seen that a phosphor with extremely high luminance can be obtained by adjusting conditions such as the raw material mixing ratio within the scope of the present invention.
FIG. 8 also shows the relative luminance (indicated by black squares in FIG. 8) and the relative emission peak intensity (in FIG. 8, when the Ce composition ratio is 0.03, with respect to the shift of the emission peak wavelength due to the addition of Mg. It is the graph which showed simply the relationship of (shown by □) from the data of the Example. The x-value of CIE chromaticity coordinates is shown on the horizontal axis, and the relative peak intensity and relative luminance are shown on the vertical axis. As the chromaticity coordinate value x increases as the Mg addition amount increases, that is, as the emission peak shifts to a longer wavelength, the relative emission peak intensity slightly decreases after increasing slightly. On the other hand, the relative luminance increases and then decreases, but all of the phosphors of the present example are higher than the luminance of the phosphor of Comparative Example 1 (relative luminance = 100). This is thought to be due to an increase in luminance due to an increase in overlap between the standard relative luminous sensitivity curve and the emission spectrum, and the effect compensates for a decrease in peak intensity. Further, the relative luminance (indicated by ● in FIG. 8) and the relative emission peak intensity (indicated by ◯ in FIG. 8) of the phosphors obtained in Examples 12 and 13 are shown in FIG. Thus, it can be seen that a phosphor with extremely high luminance can be obtained by adjusting conditions such as the raw material mixing ratio within the scope of the present invention.

(Evaluation of light emitting device)
(Example 16)
Using the phosphor manufactured in Example 14, the surface-mount white LED shown in FIG. 17 was produced and evaluated in the following procedure.
First, an LED that emits light at a wavelength of 460 nm (C460-MB290-S0100 manufactured by Cree; MB grade, light output: 9 to 10 mW) is applied to a terminal 16 of a cup part of a frame for a surface mount LED, and silver paste (conductive Bonding was performed using an adhesive mount member. Next, the electrode of the LED 11 and the terminal 15 of the frame 13 were connected using a gold wire (conductive wire) 14 of φ = 20 μm.
The red phosphor Ca _0.992 AlSiEu _0.008 N _2.85 O _0.15 and the green phosphor of Example 14 were mixed at a weight ratio of 4 to 96. A silicone resin was mixed well at a ratio of 10 g to 1 g of this phosphor mixture. Note that the red phosphor Ca _0.992 AlSiEu _0.008 N _2.85 O _0.15 was prepared by the method described in the published pamphlet of WO 2005/052087 Al.

The phosphor and resin mixture obtained in the above procedure was poured into the cup portion of the frame 13 to which the LED 11 was bonded. This was held at 150 ° C. for 1 hour to cure the silicone resin, thereby forming a phosphor-containing resin portion 12 to obtain a surface-mounted white LED.
The emission spectrum of the surface-mounted white LED obtained as described above was analyzed using Ocean Optics Inc. HR2000 system. The optical system consisting of the spectroscope, integrating sphere, optical fiber, etc. used this time was calibrated using a standard lamp with a calibrated emission distribution, and the measured values reflected the calibration data. Further, portions not described in detail in the measurement and calculation methods are JIS Z8724, Z8725, Z70.
1. Measurement and calculation were performed according to Z8726.
The white LED was driven at 20 mA at room temperature (about 24 ° C.). All the light emission from the white LED was received by an integrating sphere, and further introduced into a spectroscope by an optical fiber, and the emission spectrum was measured. As emission spectrum data, a numerical value of emission intensity was recorded every 5 nm in the range of 380 nm to 780 nm. The emission spectrum of the obtained white LED is shown in FIG. Based on this, CIE chromaticity coordinate values x and y were found to be x = 0.319 and y = 0.336. Moreover, the correlation temperature (T _CP), general color rendering index Ra, determined the value of such other color rendering index R1～R15, shown in Table 3.

(Comparative Example 5)
A surface-mounted white LED was prepared and evaluated in the same manner as in Example 16 except that the phosphor manufactured in Comparative Example 1 was used as the green phosphor. The measured emission spectrum is shown in FIG. Based on this, CIE chromaticity coordinate values x and y were found to be x = 0.314 and y = 0.336. Further, values such as correlation temperature (T _CP ) and average color rendering index Ra were also obtained and shown in Table 3.

(Comparative Example 6)
Surface mounting was performed in the same manner as in Example 16 except that a phosphor represented by the composition formula (Y _0.85 , Tb _0.15 , Ce _0.1 ) ₃ Al ₅ O ₁₂ (commonly called YAG phosphor) was used as the green phosphor. Type white LED was produced and evaluated. The measured emission spectrum is shown in FIG. Based on this, CIE chromaticity coordinate values x and y were found to be x = 0.336 and y = 0.335. Further, values such as correlation temperature (T _CP ) and average color rendering index Ra were also obtained and shown in Table 3.

It is typical sectional drawing which shows one Example of the light-emitting device comprised from the fluorescent substance of this invention as a wavelength conversion material, and a light source. It is typical sectional drawing which shows one Example of the surface emitting illumination device incorporating the light-emitting device shown in FIG. 2 is a graph showing an emission spectrum of the phosphor obtained in Example 1. 6 is a graph showing an emission spectrum of the phosphor obtained in Example 7. 6 is a graph showing an emission spectrum of the phosphor obtained in Comparative Example 1. 2 is a graph in which all CIE chromaticity coordinates of Examples 1 to 15 and Comparative Example 1 are plotted. When the composition ratio of Ce is 0.03, it is a graph showing the relationship between the relative luminance and the relative emission peak intensity with respect to the shift of the emission peak wavelength due to the addition of Mg from the data of the example (the horizontal axis is Mg amount) ) When the composition ratio of Ce is 0.03, the graph shows the relationship between the relative luminance and the relative emission peak intensity with respect to the shift of the emission peak wavelength due to the addition of Mg from the data of the examples (the horizontal axis is the CIE chromaticity). X value of coordinates). 2 is a powder X-ray diffraction pattern of the phosphor obtained in Example 1. FIG. 6 is a powder X-ray diffraction pattern of the phosphor obtained in Example 5. FIG. 7 is a powder X-ray diffraction pattern of the phosphor obtained in Example 7. FIG. 7 is a powder X-ray diffraction pattern of the phosphor obtained in Example 14. FIG. 7 is a powder X-ray diffraction pattern of the phosphor obtained in Example 15. FIG. 14 is a graph showing an emission spectrum of a surface-mounted white LED obtained in Example 16. 10 is a graph showing an emission spectrum of a surface-mounted white LED obtained in Comparative Example 5. 10 is a graph showing an emission spectrum of a surface-mounted white LED obtained in Comparative Example 6. It is a typical sectional view showing surface mount type white LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Mount lead 3 Inner lead 4 Light source 5 Phosphor containing resin part 6 Conductive wire 7 Mold member 8 Surface emitting illuminating device 9 Diffusion plate 10 Holding case 11 LED
12 Phosphor-Containing Resin Part 13 Frame 14 Conductive Wire 15 Terminal 16 Terminal

Claims (14)

A phosphor comprising a compound represented by the following general formula (I) containing a compound having a garnet structure as a matrix and a metal element of a luminescent center ion in the matrix.
M ¹ _a M ² _b X _c M ³ _d M ⁴ ₃ O _e (I)
[In formula (I), M ¹ is Mg and / or Zn , Mg accounts for 50 mol% or more of M ¹ , M ² is a divalent metal element excluding Mg and Zn , and Ca is accounted for more than 50 mol% of M ^2, X is a metal element of the luminescent center ion Ce occupies at least 50 mole% of X, M ³ is a trivalent metal element excluding X, 50 Sc is of M ³ accounted for more than mole%, M ⁴ represents a Si respectively, a, b, c, d, and e are numbers satisfying the following formulas, respectively.
0.001 ≦ a ≦ 0.5
2.5 ≦ b ≦ 3.3
0.005 ≦ c ≦ 0.5
1.5 ≦ d ≦ 2.2
e = {(a + b) × 2 + (c + d) × 3 + 12} / 2] In the general formula (I), 0.001 ≦ a ≦ 0.3.
The phosphor according to 1. In the general formula (I), 0.02 ≦ c ≦ 0.1.
The phosphor according to 1. In the general formula (I), M ² is at least one divalent metal element selected from the group consisting of Ca, Sr and Ba , and Ca accounts for 50 mol% or more of M ² The phosphor according to any one of claims 1 to 3. In the general formula (I), M ³ is at least one trivalent metal element selected from the group consisting of Al, Sc, Ga, Y, In, La, Gd, and Lu , and Sc is M ³ 5. The phosphor according to claim 1, wherein the phosphor occupies 50 mol% or more . In the general formula (I), the metal element X of the luminescent center ion other than Ce is Mn, Fe, Pr
, Nd, Sm, Eu, Gb , phosphor according to any one of claims 1 to 5, characterized in that at least one or more metal elements selected from Tb and Tm. The phosphor according to any one of claims 1 to 6 , wherein in the general formula (I), M ¹ is Mg. The phosphor according to any one of claims 1 to 7 , wherein in the general formula (I), X is Ce. The phosphor according to any one of claims 1 to 3, wherein in the general formula (I), X is Ce, M ¹ is Mg, M ² is Ca, M ³ is Sc, and M ⁴ is Si. . The phosphor according to any one of claims 1 to 9 , wherein a median diameter of the phosphor is 5 µm to 30 µm. A light source that emits light in the range from ultraviolet light to visible light, and at least one phosphor that converts wavelength of at least part of the light from the light source and emits light in a longer wavelength region than the light from the light source a light emitting device, the phosphor emitting device which comprises a phosphor according to any one of claims 1 to 1 0. The light emitting device according to claim 1 1, characterized in that emits white. An image display device which comprises a light-emitting device according to claim 1 1 or 1 2. Lighting apparatus comprising a light-emitting device according to claim 1 1 or 1 2.

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