JP2009161576A - Phosphor and light emitting device using the same - Google Patents

Abstract

Provided is a high-performance phosphor excellent in efficiency for converting visible light into broadband red light emission.
A phosphor having a chemical composition represented by the following formula [1].
M ¹ _1-x Eu _x M ² _y O _z [1]
(In the above formula [1],
M ¹ represents a divalent metal element in which M ¹ is essential for Sr.
M ² represents a trivalent metal element essentially containing Sc or Lu.
x, y, and z are each
0.0001 ≦ x ≦ 0.1
1.8 ≦ y ≦ 2.2
3.6 ≦ z ≦ 4.4
Represents a number that satisfies )
[Selection] Figure 4

Description

  The present invention relates to a phosphor and a method for producing the same, a phosphor-containing composition and a light emitting device using the phosphor, and an image display device and an illumination device using the light emitting device. Specifically, the present invention relates to a phosphor excellent in efficiency for converting visible light into red light, a method for producing the same, a phosphor-containing composition and a light-emitting device using the phosphor, and the light-emitting device. The present invention relates to an image display device and a lighting device.

  A white LED in which a blue LED is used as an excitation light source and combined with a phosphor has been put into practical use. Possible phosphors capable of converting visible light such as blue light include sulfide phosphors, oxysulfide phosphors, oxide phosphors, nitride phosphors, and oxynitride phosphors. Is mentioned. Above all, oxide phosphors have been used for many years as phosphors for fluorescent lamps, and their manufacturing methods have been established, and because they are thermodynamically stable, they are suitable as light emitting devices and the like. Can be used.

As an oxide-based red phosphor, SrY ₂ O ₄ : Eu ³⁺ phosphor is reported in Non-Patent Document 1. This SrY ₂ O ₄ : Eu ³⁺ phosphor emits light when the excitation wavelength is 300 nm or less, and is considered not to be excited by visible light (Non-patent Document 1 FIG. 4). Further, this SrY ₂ O ₄ : Eu ³⁺ phosphor emits light in a red region having a wavelength of 580 nm to 620 nm, and is emitted by an ff transition derived from Eu ³⁺ , and thus has a narrow half-value width and a narrow band. (Non-Patent Document 1 FIG. 5). Note that Y ₂ O ₃ : Eu ³⁺ phosphor, which has been used for three-wavelength fluorescent lamps for a long time, also emits light due to Eu ^{3 + -derived} ff transition and is not excited by visible light.

Patent Document 1 describes that the SrY ₂ O ₄ : Eu ²⁺ phosphor and the SrY ₂ O ₄ : Eu ³⁺ phosphor emit light in red with excitation light having a wavelength of 254 nm. Although emission of Eu ²⁺ and Eu ³⁺ can be discriminated from the emission spectrum, Patent Document 1 does not disclose the emission spectrum. Further, there is no description as to whether or not these phosphors can be excited with visible light.

Non-Patent Document 2 reports that an SrSc ₂ O ₄ single crystal having Yb ³⁺ as the emission center was grown. Yb ³⁺ is an ff transition, and this SrSc ₂ O ₄ single crystal is a laser that emits light in the near infrared region. Note that this Non-Patent Document 2 does not describe a phosphor.
WO2006 / 111568 Liya Zhou, Jianxin Shi, Menglian Gong, Journal of Luminescence113 (2005) 285-290 M. Romain GAUME, pour obtenir le grade de DoctEur de l'Universite Pierre et Marie Curie-Paris VI, "Relations structures-proprietes dans les lasers solides de puissance a l'ytterbium. Elaboration et caracterisation de nouveaux materiaux et de cristaux composites soudes par diffusion "

  The red light emitter used in combination with the LED is required to be able to be excited by blue light, to have a low environmental load, and to be manufactured safely. Further, from the viewpoint of color rendering properties, a phosphor having a longer wavelength red light emitting component is advantageous, and therefore a deep red light emitting phosphor (hereinafter referred to as “deep red phosphor”) is required. However, conventionally known Eu-activated red phosphors represented by the phosphors described in Patent Document 1 and Non-Patent Document 1 are all insufficient in terms of excitation wavelength, color rendering, and the like. there were. Therefore, a high-quality red phosphor suitable for the above purpose has been desired.

  The present invention has been made in view of the above-described problems, and its object is to provide a high-quality phosphor excellent in efficiency for converting visible light into broadband red light emission, and to use this phosphor. The object is to provide a phosphor-containing composition and a light-emitting device, and an image display device and a lighting device using the light-emitting device.

In view of the above problems, the present inventors have studied in detail the combination of constituent elements contained in the phosphor and the composition ratio of each element in order to search for a new phosphor. It was found that the phosphor to be excited can be excited by visible light such as blue light. Further, the present inventors have found that this phosphor exhibits very excellent characteristics as a red light source and can be suitably used for applications such as a light-emitting device, and have completed the present invention.
That is, this invention makes the following a summary.

(1) A phosphor having a chemical composition represented by the following formula [1].
M ¹ _1-x Eu _x M ² _y O _z [1]
(In the above formula [1],
M ¹ represents a divalent metal element in which M ¹ is essential for Sr.
M ² represents a trivalent metal element essentially containing Sc or Lu.
x, y, and z are each
0.0001 ≦ x ≦ 0.1
1.8 ≦ y ≦ 2.2
3.6 ≦ z ≦ 4.4
Represents a number that satisfies )

(2) The phosphor according to (1), wherein in the formula [1], Eu is divalent Eu.

(3) In the formula [1], and the content of Sr in ^{M 1} is ^{M 1} total 40 mol% or more, in total content of Sc and Lu in ^{M 2} is ^{M 2} total 50 mol% or more The phosphor according to (1) or (2), which is characterized in that it exists.

(4) In the formula [1], M ¹ is Sr alone or Sr is essential, and is one or two metal elements selected from the group consisting of Ca and Ba, and M ² is: It is a metal element consisting only of Sc and / or Lu, or one or more metal elements selected from the group consisting of Sc, Al, Y, Lu, Gd, and La, which is essential for Sc or Lu. The phosphor according to any one of (1) to (3), wherein

(5) The phosphor according to any one of (1) to (4), wherein the phosphor has an emission peak in a wavelength range of 610 nm to 750 nm.

(6) The phosphor according to any one of (1) to (5), wherein the half width of the emission peak is 70 nm or more and 120 nm or less.

(7) The phosphor according to any one of (1) to (6), wherein in the formula [1], M ² includes Sc and Lu.

(8) A phosphor characterized by satisfying the following conditions (1) to (4).
(1) Oxide phosphor showing red emission based on Eu ²⁺ emission
(2) Excited by light in the wavelength range from 420 nm to 550 nm
(3) The emission peak has a wavelength in the range of 610 nm to 750 nm, and the half width of the emission peak is 70 nm or more.
(4) The internal quantum efficiency in excitation with light having a wavelength of 455 nm at room temperature is 5% or more.

(9) The phosphor according to (8), which contains Sr.

(10) The phosphor according to (8) or (9), which contains Sc.

(11) The phosphor according to any one of (8) to (10), characterized by containing Lu.

(12) A method for producing the phosphor according to any one of (1) to (11), comprising the step of firing the phosphor material in a strong reducing atmosphere. .

(13) A phosphor-containing composition comprising the phosphor according to any one of (1) to (11) and a liquid medium.

(14) A first light emitter and a second light emitter that emits visible light when irradiated with light from the first light emitter, and the second light emitter includes (1) to (11). A light emitting device comprising one or more of the phosphors according to any one of the above as a first phosphor.

(15) The second phosphor includes one or more phosphors having different emission peak wavelengths from the first phosphor as the second phosphor. (15) Light emitting device.

(16) The first light emitter has a light emission peak in a wavelength range of 420 nm to 500 nm, and the second light emitter emits light in a wavelength range of 500 nm to 610 nm as the second phosphor. The light-emitting device according to (15), comprising at least one phosphor having a peak.

(17) The first light emitter has a light emission peak in a wavelength range of 300 nm to 420 nm, and the second light emitter emits light in a wavelength range of 420 nm to 500 nm as the second phosphor. The light-emitting device according to (15), comprising at least one phosphor having a peak and at least one phosphor having a light emission peak in a wavelength range of 500 nm to 610 nm.

(18) An image display device comprising the light-emitting device according to any one of (14) to (17) as a light source.

(19) An illumination device comprising the light-emitting device according to any one of (14) to (17) as a light source.

According to the present invention, it is possible to provide a phosphor that can be excited by visible light and emits a broadband red light. The phosphor of the present invention can exhibit a wide range of red light emission by adjusting the composition.
Further, by using a composition containing this phosphor, a light-emitting device with high efficiency and high characteristics can be obtained.
This light-emitting device is suitably used for an image display device or a lighting device.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following description, and various modifications can be made within the scope of the gist of the present invention.

1) In addition, the numerical range represented using “to” in this specification means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
2) In addition, the relationship between the color name and the chromaticity coordinates in the specification is based on the JIS standard (JISZ8110).
3) Moreover, in the composition formula of the phosphors in this specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed by separating them with commas (,), it indicates that one or more of the listed elements may be contained in any combination and composition. For example, the composition formula “(Ba, Sr, Ca) Al ₂ O ₄ : Eu” has “BaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, and “CaAl ₂ O ₄ : Eu”. “Ba _1-α Sr _α Al ₂ O ₄ : Eu”, “Ba _1-α Ca _α Al ₂ O ₄ : Eu”, “Sr _1-α Ca _α Al ₂ O ₄ : Eu”, “Ba _1-α-β Sr _α Ca _β Al ₂ O ₄ : Eu” is shown in a comprehensive manner (wherein 0 <α <1, 0 <β <1, 0 <Α + β <1).

[1. Phosphor]
[1-1. composition〕
The phosphor of the present invention is a phosphor having an oxide activated by Eu as a base crystal. At least a part of Eu in the phosphor of the present invention is a divalent ion (Eu ²⁺ ). Specifically, the ratio of Eu ²⁺ to the total Eu is preferably as high as possible, and is usually 50% or more, preferably 80% or more, more preferably 90% or more, and most preferably 95% or more.
The ratio of Eu ²⁺ to the total Eu can be measured, for example, by the X-ray absorption near-edge structure method of the Eu-L3 absorption edge. For example, in I. Hirosawa, et al., Journal of the SID, vol. 13/8, pp. 673-677 (2005), Eu ²⁺ and Eu ^{3+ in a} BaMgAl ₁₀ O ₁₇ : Eu ²⁺ phosphor are obtained by this method. An example of measuring the ratio to is reported.
Eu ²⁺ serves as a luminescent center ion in the phosphor. Since the light emission by Eu ²⁺ is derived from the 5d-4f transition which is an allowable transition, the transition probability is high, and the phosphor using Eu ²⁺ as the light emission center has high light emission efficiency. In addition, when Eu ²⁺ and the host crystal are combined appropriately, it can absorb light having a longer wavelength than phosphors that have been used for a long time, that is, purple, blue-violet, blue, blue-green, and green light. Thus, it becomes possible to efficiently convert light such as near-ultraviolet LED, blue LED, and laser.

As a constituent element of the host crystal, it is preferable to have a divalent metal element that essentially requires Sr, and it is also preferable to have a trivalent metal element that essentially requires Sc. Further, Lu may be provided instead of Sc or in addition to Sc.
Among them, the composition of the phosphor of the present invention preferably has a composition represented by the following formula [1].
M ¹ _1-x Eu _x M ² _y O _z [1]
(In the above formula [1],
M ¹ represents a divalent metal element in which M ¹ is essential for Sr.
M ² represents a trivalent metal element essentially containing Sc or Lu.
x, y, and z are each
0.0001 ≦ x ≦ 0.1
1.8 ≦ y ≦ 2.2
3.6 ≦ z ≦ 4.4
Represents a number that satisfies )

In the formula [1], M ¹ is a divalent metal element in which Sr is essential. M ¹ may contain an element other than Sr. The element contained in M ¹ other than Sr is preferably an alkaline earth metal element, and specifically, one or more elements selected from the group consisting of Ca, Ba, Mg, Zn, and Cd. Of these, Ca and / or Ba are particularly preferable. Therefore, M ¹ is preferably one or more elements selected from the group consisting of Sr, Ca, and Ba, in which Sr is essential.

The M ¹ overall structure element ratio, the content of Sr is not less than 40 mol% of the total M ^1, more preferably 60 mol% or more, more preferably 80 mol% or more . This is because as the Sr content increases, the luminous efficiency tends to improve.

When Ba is contained as M ¹ , the amount is preferably 30 mol% or less, more preferably 10 mol% or less of the entire M ¹ . When there is too much Ba, the target crystal may not be obtained and light may not be emitted.

Further, when Ca is contained as M ¹ , the amount is preferably 50 mol% or less, more preferably 20 mol% or less of the entire M ¹ . If the amount of Ca is large, the emission peak tends to shift to the longer wavelength side. If the amount of Ca is too large, the target crystal may not be obtained and light may not be emitted.

In the formula [1], M ² represents a trivalent metal element essentially containing Sc or Lu. Here, M ² may be have a Sc or Lu alone, may have both Sc and Lu. M ² may contain an element other than Sc and Lu. As elements other than Sc and Lu, one or more elements selected from the group consisting of Al, Y, Gd, La, Ga, and In are preferable, and from the group consisting of Al, Y, Gd, and La, One or more selected elements are more preferred. Therefore, M ² is preferably one or more elements selected from the group consisting of Sc, Al, Y, Lu, Gd, and La, which essentially require Sc and / or Lu.

The M ² overall structure element ratio, the total content of Sc and Lu in ^{M 2} is preferably at ^{M 2} total 50 mol% or more. Here, the ratio of Sc and Lu is not particularly limited, and as the Sc increases, the emission peak wavelength tends to shift to the longer wavelength side, and as the Lu increases, the emission peak wavelength tends to shift to the shorter wavelength side. Therefore, the mixing ratio of Sc and Lu may be adjusted so that the target emission color can be obtained. For example, when a deep red color (hereinafter referred to as “deep red”) having an emission peak wavelength of 665 nm to 700 nm is desired, the molar ratio of Sc to Lu (Sc / Lu) is set to 7/3 or more. Is preferable, and is more preferably 8/2 or more. In order to adjust the emission color so that the luminance and color purity are balanced (specifically, the region where the emission peak wavelength is about 640 nm to 670 nm), the value of Sc / Lu is preferably 1 / 1 or more, more preferably 3/2 or more, preferably 4/1 or less, more preferably 7/3 or less. In addition, when the color purity is slightly inferior, but it is desired to obtain a high-brightness red to reddish orange color (specifically, a region where the emission peak wavelength is about 600 nm to 640 nm), the value of Sc / Lu is set to 1 / The light emission peak wavelength tends to shift to the short wavelength side as the Sc ratio is decreased, and therefore it is preferable to adjust appropriately.

  In the formula [1], x is a number representing the number of moles of Eu, and is usually 0.0001 or more, preferably 0.001 or more, more preferably 0.002 or more, and usually 0.1 or less, preferably Is 0.03 or less, more preferably 0.02 or less. Even if the value of x is too small or too large, the emission peak intensity tends to decrease.

In the formula [1], y is a number representing the number of moles of M ² and is usually 1.8 or more, preferably 1.9 or more, more preferably 1.95 or more, and usually 2.2 or less. Preferably it is 2.1 or less, More preferably, it is 2.05 or less. When the phosphor of the present invention consists of a single crystal phase, the value of y is 2.0 in terms of crystallography. However, even when the phosphor of the present invention is composed of a single crystal phase, y may deviate from 2.0 due to various lattice defects. In such a case, light emission is caused by the lattice defects. Efficiency often decreases. Accordingly, the value of y is preferably close to 2.0, and the light emission efficiency tends to decrease if the value is too large or too small.

  In the formula [1], z is a number representing the number of moles of O, usually 3.6 or more, preferably 3.85 or more, more preferably 3.925 or more, and usually 4.4 or less, preferably Is 4.15 or less, more preferably 4.075 or less. If the value of z is too small or too large, the light emission efficiency tends to decrease.

The phosphor represented by the formula [1] more preferably has a composition represented by the following formula [2].
(Sr, Ba, Ca) _1-x Eu _x (Sc, Lu) _y O _z [2]
(In the above equation [2],
x, y, and z are each
0.0001 ≦ x ≦ 0.1
1.8 ≦ y ≦ 2.2
3.6 ≦ z ≦ 4.4
Represents a number that satisfies )

Specific examples of preferred compositions of the phosphor of the present invention are listed below, but the composition of the phosphor of the present invention is not limited to the following examples.
In the composition formulas representing the following specific examples, Eu is substituted in a range of 0.1 mol% to 1 mol% of Sr.
SrSc ₂ O ₄ : Eu
Sr (Sc _0.8 Lu _0.2 ) ₂ O ₄ : Eu
Sr (Sc _0.7 Lu _0.3 ) ₂ O ₄ : Eu
Sr (Sc _0.6 Lu _0.4 ) ₂ O ₄ : Eu
SrLu ₂ O ₄ : Eu

[1-2. Characteristics of phosphor
The phosphor of the present invention is an oxide phosphor that exhibits red light emission based on Eu ²⁺ light emission.
The phosphor of the present invention can be excited by light having a wavelength of 420 nm or more and 550 nm or less. For example, when excited by blue light having a wavelength of 455 nm, the phosphor has a light emission peak in the range of wavelengths of 610 nm or more and 750 nm or less. It is preferable that the half width of the emission peak is 70 nm or more.
Furthermore, the phosphor of the present invention preferably has an internal quantum efficiency of 5% or more in excitation with light having a wavelength of 455 nm at room temperature.
The characteristics of the phosphor of the present invention as described above will be described in detail below.

{Characteristics related to emission spectrum}
The phosphor of the present invention preferably has the following characteristics when an emission spectrum is measured when excited with light having a wavelength of 455 nm, in view of the use as a red (red-orange to deep red) phosphor. .

<Peak emission wavelength>
First, the phosphor of the present invention preferably has a peak wavelength λ _p (nm) in an emission spectrum of usually 610 nm or more, particularly 630 nm or more, and usually 750 nm or less, particularly 700 nm or less. While this emission peak wavelength lambda _p tends to carry a too short Daidaimi, luminosity close to the near-infrared region and too long tends to be low. The peak wavelength lambda _p is preferably appropriately adjusted depending on the application.

  Further, the relative intensity of the emission peak of the phosphor of the present invention (herein, the relative intensity is a relative intensity with 100 as the emission intensity when P46-Y3 manufactured by Kasei Optonix Co., Ltd. is excited with light having a wavelength of 455 nm). .) Is preferably higher.

<Half width of emission peak>
In addition, the phosphor of the present invention has a full width at half maximum (hereinafter abbreviated as “FWHM” where appropriate) in the above-mentioned emission spectrum, usually 70 nm or more, particularly 80 nm or more, and usually 120 nm or less. Especially, it is preferable that it is the range of 110 nm or less. If the half-value width FWHM is too narrow, the emission intensity tends to decrease, and if it is too wide, the color purity tends to decrease.

  In order to excite the phosphor of the present invention with light having a wavelength of 455 nm, for example, a GaN-based light emitting diode can be used. The measurement of the emission spectrum of the phosphor of the present invention and the calculation of the emission peak wavelength, peak relative intensity, and peak half width are, for example, a 150 W xenon lamp as an excitation light source and a multichannel CCD detector C7041 as a spectrum measurement device. This can be carried out using a fluorescence measuring apparatus (manufactured by JASCO Corporation) equipped with (manufactured by Hamamatsu Photonics).

<Luminescent color>
As for the luminescent color of the phosphor of the present invention, x is usually 0.4 or more, preferably 0.6 or more, and y is usually 0.55 or less, preferably 0.45 or less, as chromaticity coordinate values based on JIS Z8701. More preferably, it is 0.4 or less.
<Excitation wavelength>
The phosphor of the present invention is preferably excitable with visible light in a wavelength range of usually 400 nm or more, particularly 420 nm or more, more preferably 430 nm or more, and usually 500 nm or less, especially 480 nm or less, and more preferably 470 nm or less. Thereby, for example, a semiconductor light emitting element that emits light in a blue-violet, blue, or blue-green region can be suitably used for a light-emitting device having the first light emitter.

Moreover, it is preferable that the phosphor of the present invention can be excited by light having a shorter wavelength than visible light.
The excitation wavelength of the specific phosphor of the present invention is usually 250 nm or more, especially 280 nm or more, and usually 400 nm or less, particularly 370 nm or less, and even in the ultraviolet region in the wavelength range of 350 nm or less. It is preferable. Thereby, for example, it can be suitably used for a light emitting device using a semiconductor light emitting element or the like that emits light in the ultraviolet region as a first light emitter.

  The excitation spectrum can be measured at room temperature, for example, 25 ° C., using a fluorescence spectrophotometer F-4500 type (manufactured by Hitachi, Ltd.). The excitation peak wavelength can be calculated from the obtained excitation spectrum.

<Quantum efficiency, etc.>
The phosphor of the present invention is more preferable as its internal quantum efficiency is higher. The value is usually 5% or more, preferably 30% or more, and more preferably 50% or more. Here, the internal quantum efficiency means the ratio of the number of photons emitted to the number of photons of excitation light absorbed by the phosphor. If the internal quantum efficiency is low, the efficiency when used in a light-emitting device tends to decrease.

  The phosphor of the present invention is preferably as its absorption efficiency is high. The value is usually 50% or more, preferably 60% or more, and more preferably 80% or more. When the absorption efficiency is low, the light emission efficiency tends to decrease.

  The external quantum efficiency is expressed by the product of the internal quantum efficiency and the absorption efficiency as described in the following description. The phosphor of the present invention preferably has a higher external quantum efficiency, and its value is usually 5% or more, preferably 15% or more, more preferably 30% or more. If the external quantum efficiency is too small, it may be difficult to design a light emitting device with high light emission intensity.

(Measurement method of absorption efficiency, internal quantum efficiency, and external quantum efficiency)
A method for obtaining the absorption efficiency αq, internal quantum efficiency ηi, and external quantum efficiency ηo of the phosphor will be described below.

  First, a phosphor sample to be measured (for example, a powder form) is packed in a cell with a sufficiently smooth surface so that measurement accuracy is maintained, and is attached to a condenser such as an integrating sphere. The use of a condenser such as an integrating sphere makes it possible to count all photons reflected by the phosphor sample and photons emitted from the phosphor sample due to the fluorescence phenomenon, that is, not counted but out of the measurement system. This is to eliminate the photons that fly away.

  A light-emitting source for exciting the phosphor is attached to the condenser such as an integrating sphere. This light source is, for example, an Xe lamp or the like, and is adjusted using a filter, a monochromator (diffraction grating spectrometer), or the like so that the emission peak wavelength is monochromatic light of, for example, 405 nm or 455 nm. The phosphor sample to be measured is irradiated with light from the light emission source whose emission peak wavelength is adjusted, and a spectrum including light emission (fluorescence) and reflected light is measured by a spectroscopic measurement device such as MCPD2000, MCPD7000 manufactured by Otsuka Electronics Co., Ltd. Use to measure. The spectrum measured here is actually reflected light that has not been absorbed by the phosphor among the light from the excitation light source (hereinafter simply referred to as excitation light), and the phosphor absorbs the excitation light. Thus, light of another wavelength (fluorescence) emitted by the fluorescence phenomenon is included. That is, the region near the excitation light corresponds to the reflection spectrum, and the longer wavelength region corresponds to the fluorescence spectrum (sometimes referred to herein as the emission spectrum).

The absorption efficiency αq is a value obtained by dividing the number of photons N _abs of the excitation light absorbed by the phosphor sample by the total number of photons N of the excitation light.

First, the total photon number N of the latter excitation light is obtained as follows. That is, a reflecting plate such as a substance having a reflectance R of almost 100% with respect to excitation light, for example, “Spectralon” manufactured by Labsphere (having a reflectance R of 98% with respect to excitation light of 450 nm) is measured. In the same manner as the phosphor sample, it is attached to a condenser such as the integrating sphere described above, and the reflection spectrum I _ref (λ) is measured using the spectrometer. The numerical value of the following (formula I) obtained from the reflection spectrum I _ref (λ) is proportional to N.

Here, the integration interval may be substantially performed only in the interval where I _ref (λ) has a significant value.
The number N _abs of the photons in the excitation light that is absorbed in the phosphor sample is proportional to the amount calculated by the following equation (II).

Here, I (λ) is a reflection spectrum when a phosphor sample for which the absorption efficiency αq is to be obtained is attached. The integration interval in (Formula II) is the same as the integration interval defined in (Formula I). By limiting the integration interval in this way, the second term in (Equation II) corresponds to the number of photons generated by reflecting the excitation light from the phosphor sample to be measured, that is, as the measurement target. Among all photons generated from the phosphor sample, the photons derived from the fluorescence phenomenon are excluded. Since an actual spectrum measurement value is generally obtained as digital data divided by a certain finite bandwidth with respect to λ, the integrals of (Equation I) and (Equation II) are obtained by the sum based on the bandwidth.
From the above, αq = N _abs / N = (Formula II) / (Formula I).

Next, a method for obtaining the internal quantum efficiency ηi will be described. ηi is a value obtained by dividing the number N _abs of photons number NPL of photons originating from the fluorescence phenomenon absorbed by the phosphor sample.
Here, NPL is proportional to the amount obtained by the following (formula III).

At this time, the integration interval is limited to the wavelength range of photons derived from the fluorescence phenomenon of the phosphor sample. This is because the contribution of photons reflected from the phosphor sample is removed from I (λ). Specifically, the lower limit of the integration interval of (Equation III) is the upper end of the integration interval of (Equation I), and the upper limit is a range necessary and sufficient to include photons derived from fluorescence.
As described above, the internal quantum efficiency ηi is obtained as ηi = (formula III) / (formula II).

The integration from the spectrum that has become digital data is the same as the case where the absorption efficiency αq is obtained.
Then, the external quantum efficiency ηo is obtained by taking the product of the absorption efficiency αq and the internal quantum efficiency ηi obtained as described above. Or it can also obtain | require from the relationship of (eta) == (Formula III) / (Formula I). ηo is a value obtained by dividing the number NPL of photons derived from fluorescence by the total number N of photons of excitation light.

<Weight median diameter>
The phosphor of the present invention preferably has a weight median diameter in the range of usually 2 μm or more, especially 5 μm or more, and usually 30 μm or less, especially 20 μm or less. If the weight median diameter is too small, the luminance is lowered and the phosphor particles tend to aggregate, which is not preferable. On the other hand, when the weight median diameter is too large, there is a tendency that uneven coating or blockage of a dispenser or the like occurs, which is not preferable.
The weight median diameter of the phosphor of the present invention can be measured using a device such as a laser diffraction / scattering particle size distribution measuring device.

[1-3. (Method for producing phosphor)
The method for producing the phosphor of the present invention is not particularly limited. For example, in the above formula [1], the raw material of the metal element M ¹ (hereinafter referred to as “M ¹ source” as appropriate) and the raw material of the metal element M ² (hereinafter referred to as appropriate) (Referred to as “M ² source”) and the raw material of the element Eu as the activating element (hereinafter referred to as “Eu source” as appropriate) (mixing step), and firing the resulting mixture (firing step). Can be manufactured.

<Raw material>
Examples of the M ¹ source, the M ² source, and the Eu source used for producing the phosphor of the present invention include oxides, hydroxides, carbonates, nitrates, sulfates of the elements M ¹ , M ^2, and Eu, Examples thereof include oxalates, carboxylates and halides. From these compounds, the reactivity to the composite oxide, the low generation amount of NO _x , SO _{x and the} like during firing may be selected as appropriate.

Specific examples of the M ¹ source are listed as follows for each type of M ¹ element.

Specific examples of the Sr source include SrO, Sr (OH) ₂ .8H ₂ O, SrCO ₃ , Sr (NO ₃ ) ₂ , SrSO ₄ , Sr (C ₂ O ₄ ) · H ₂ O, Sr (OCOCH ₃ ). _{2 · 0.5H 2 O, SrCl 2} , Sr 3 N 2, SrNH and the like. Among these, SrCO ₃ is preferable. This is because the stability in the air is good, it is easily decomposed by heating, it is difficult for undesired elements to remain, and it is easy to obtain high-purity raw materials. In addition, when using carbonate as a raw material, it is preferable to pre-fire and use carbonate as a raw material.

Specific examples of the Ba source include BaO, Ba (OH) ₂ .8H ₂ O, BaCO ₃ , Ba (NO ₃ ) ₂ , BaSO ₄ , Ba (C ₂ O ₄ ), Ba (OCOCH ₃ ) ₂ , BaCl _2. , Ba ₃ N ₂ , BaNH and the like. Of these, carbonates, oxides, and the like can be preferably used, but carbonates are more preferable from the viewpoint of handling because oxides easily react with moisture in the air. Of these, BaCO ₃ is preferable. This is because the stability in the air is good, and since it is easily decomposed by heating, undesired elements hardly remain and it is easy to obtain a high-purity raw material. In addition, when using carbonate as a raw material, it is preferable to pre-fire and use carbonate as a raw material.

Specific examples of the Ca source include CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, Ca (C ₂ O ₄ ) · H ₂ O, and Ca. _{(OCOCH 3) 2 · H 2} O, CaCl 2, Ca 3 N 2, CaNH and the like. Of these, CaCO ₃ and CaCl ₂ are preferable.

Specific examples of the Zn source include zinc compounds such as ZnO, ZnF ₂ , ZnCl ₂ , Zn (OH) ₂ , Zn ₃ N ₂ , ZnNH (but may be hydrates). Of these, ZnF ₂ .4H ₂ O (however, it may be an anhydride) is preferable from the viewpoint that the effect of promoting particle growth is high. Incidentally, ZnF _2, as described below, may be used as a flux.

Specific examples of the Eu source include Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (OCO) ₆ , EuCl ₂ , EuCl ₃ , Eu (NO ₃ ) ₃ .6H ₂ O, and the like. Of these, Eu ₂ O ₃ , Eu (NO ₃ ) ₃ .6H ₂ O, and EuCl ₂ are preferable.

Specific examples of M ² source, when listed separately for each type of M ² element is as follows.

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 and the} like. Among these, Sc ₂ O ₃ is preferable because it is easily available and a high-purity product is highly likely to be obtained.

Examples of the Lu source compound include Lu ₂ O ₃ , Lu ₂ (SO ₄ ) ₃ , and LuCl ₃ . Among them, Lu ₂ O ₃ is preferable because it is easily available and a high-purity product is highly likely to be obtained.

As specific examples of trivalent metals other than Sc and Lu, Y source compounds include 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 and the} like, and as the Al source compound, Al ₂ O ₃ , Al (OH) ₃ , AlOOH, Al (NO ₃ ) _{3 · 9H 2 O, Al 2} (SO 4) 3, AlCl 3 or the like may be mentioned, respectively.

Incidentally, M ¹ source described above, M ² source and Eu source, respectively, may be used alone, or as a combination of two or more kinds in any combination and in any ratio.
It is more preferable to use a coprecipitation raw material in which elements as raw material components are mixed at an atomic level.

<Mixing process>
The method of mixing the M ¹ source, the M ² source, and the Eu source is not particularly limited, but examples include the following methods (A) and (B).

(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., pulverization using mortar and pestle, etc., mixer such as ribbon blender, V-type blender and Henschel mixer, or mortar and pestle A dry mixing method in which raw materials such as an M ¹ source, an M ² source, and an Eu source are pulverized and mixed in combination with mixing.

(B) A solvent or dispersion medium such as water is added to raw materials such as M ¹ source, M ² source, and Eu source, and mixed using a pulverizer, mortar and pestle, or evaporating dish and stirring rod, etc., solution or slurry A wet mixing method in which the product is dried by spray drying, heat drying, natural drying, or the like.

<Baking process>
(Baking conditions)
In the firing step, the mixture of raw materials such as the M ¹ source, M ² source, and Eu source obtained by the above mixing step is usually put in a heat-resistant container such as a crucible or a tray made of a material having low reactivity with each raw material. , By heating.

  As the material of the heat-resistant container used at the time of firing, ceramics such as alumina, quartz, boron nitride, silicon carbide, silicon nitride, magnesium oxide, metals such as platinum, molybdenum, tungsten, tantalum, niobium, iridium, rhodium, or the like An alloy containing carbon as a main component, carbon (graphite), and the like can be given. Here, when selected from the viewpoint of cost and availability, a heat-resistant container made of alumina is preferable, and when selected from the viewpoint of low reactivity with each raw material, a heat-resistant container made of platinum or molybdenum is used. preferable.

  The filling rate when filling the phosphor material into the heat-resistant container varies depending on the firing conditions, but it is sufficient to fill the fired product so that it is not difficult to grind in the post-treatment step described later, and usually 10% by volume. As mentioned above, it is 90 volume% or less normally.

Further, when it is desired to increase the amount of the phosphor raw material to be processed at a time, it is preferable that heat is uniformly circulated in the heat-resistant container, for example, by decreasing the rate of temperature rise.
Moreover, it is preferable that the filling rate at the time of filling the heat-resistant container in the furnace is such that the heat does not become uneven between the heat-resistant containers in the furnace.
Furthermore, in the above baking, when the number of heat-resistant containers in the baking furnace is large, for example, to make the heat transfer to each heat-resistant container uniform, such as slowing the temperature increase rate, It is preferable for firing without unevenness.

In the temperature raising process at the time of firing, it is preferable that a part of the temperature is reduced. Specifically, at any time when the temperature is preferably room temperature or higher, and preferably 1500 ° C. or lower, more preferably 1200 ° C. or lower, and still more preferably 1000 ° C. or lower, In general, it is preferably in the range of 10 ⁻² Pa to less than 0.1 MPa. Among them, it is preferable to introduce an inert gas or a reducing gas, which will be described later, into the system after reducing the pressure in the system, and to raise the temperature in that state.

  At this time, if necessary, it may be maintained at the target temperature for usually 1 minute or longer, preferably 5 minutes or longer, more preferably 10 minutes or longer. The holding time is usually 5 hours or less, preferably 3 hours or less, more preferably 1 hour or less.

  The temperature during firing (maximum temperature reached) is usually 1300 ° C. or higher, preferably 1400 ° C. or higher, and usually 1600 ° C. or lower, preferably 1550 ° C. or lower. If the firing temperature is too low, crystals do not grow sufficiently and the particle size tends to be small. On the other hand, if the firing temperature is too high, the crystal tends to grow too much and the particle size tends to increase, and the phosphor raw material is likely to react with the aforementioned heat-resistant container, or the heat-resistant container itself is altered by heat, There is also the possibility of deformation.

  The rate of temperature rise is usually 1 ° C./min or more, preferably 3 ° C./min or more, and usually 20 ° C./min or less, preferably 10 ° C./min or less. Below this range, the firing time may be longer. Moreover, when it exceeds this range, a baking apparatus, a container, etc. may be damaged.

  The pressure at the time of firing is not particularly limited because it varies depending on the firing temperature or the like, but is usually 0.01 MPa or more, preferably 0.1 MPa or more, and usually 200 MPa or less, preferably 100 MPa or less. Among these, industrially, it is usually about atmospheric pressure to about 0.3 MPa, and atmospheric pressure is preferable in terms of cost and labor.

  The firing time varies depending on the temperature and pressure during firing, but is usually in the range of 10 minutes or longer, usually 24 hours or shorter, preferably 1 hour or longer, and preferably 6 hours or shorter.

In the phosphor of the present invention, it is essential that Eu is present as a divalent Eu ion. Therefore, when a compound having trivalent Eu is used as the Eu source, the firing atmosphere is reduced. It is necessary to have a sex atmosphere.
As a specific example, it is carried out in an atmosphere of any one of gases such as carbon monoxide, carbon dioxide, nitrogen, hydrogen, and argon, or in a mixed atmosphere of two or more. Among these, it is preferable to contain reducing gas, such as carbon monoxide and hydrogen, and especially under a nitrogen atmosphere containing hydrogen.

  Here, the hydrogen content contained in the hydrogen-containing nitrogen atmosphere is usually 1% by volume or more, preferably 2% by volume or more, and usually 5% by volume or less, and the most preferable hydrogen content is 4% by volume. . If the hydrogen content in the atmosphere is too high, the safety may decrease, and if it is too low, a sufficient reducing atmosphere cannot be achieved.

Furthermore, in the present invention, as a method of reducing trivalent Eu ions to bivalent during firing, the firing atmosphere is a reducing atmosphere such as a hydrogen-containing nitrogen atmosphere, and solid carbon is also present in the reaction system. Therefore, it is preferable to reduce the oxygen concentration to a strong reducing atmosphere.
That is, in general, a small amount of air may enter the baking apparatus, but by coexisting solid carbon, the influence is reduced and the phosphor of the present invention is stably produced. be able to.

  The type of solid carbon is not particularly limited, and any type of solid carbon can be used. Examples thereof include carbon black, activated carbon, pitch, coke, graphite (graphite) and the like. The reason why it is preferable to use solid carbon is that oxygen in the firing atmosphere reacts with the solid carbon to generate carbon monoxide gas, and this carbon monoxide reacts with oxygen in the firing atmosphere to form carbon dioxide. This is because the oxygen concentration in the firing atmosphere can be reduced. Among the above-mentioned examples, activated carbon having high reactivity with oxygen is preferable. The shape of the solid carbon includes powder, bead, particle, block, etc., but is not particularly limited.

  The amount of solid carbon to be coexisted is usually 0 with respect to the produced phosphor from the viewpoint of the balance between the properties of the phosphor and the productivity, although it depends on the amount of the phosphor raw material processed at one time and other firing conditions. .1% by weight or more, preferably 1% by weight or more, more preferably 10% by weight or more, and further preferably 15% by weight or more.

Further, by using a graphite crucible as a firing container, it is possible to obtain the same effect as the coexistence of solid carbon. On the other hand, when a crucible made of a material other than carbon such as an alumina crucible is used, it is preferable that solid carbon such as graphite and activated carbon coexist separately. The shape of the solid carbon is not particularly limited, and examples thereof include a bead shape, a granular shape, and a block shape.
In addition, it is preferable to perform baking under sealed conditions, such as covering the crucible.

  Here, “calcining in the presence of solid carbon” means that the phosphor raw material and the solid carbon are present in the same baking container. In this case, in particular, the phosphor raw material and the solid carbon Are preferably arranged close to each other.

  As a method of placing solid carbon close to the phosphor raw material, the solid carbon is put in a container different from the container containing the phosphor raw material, and these containers are installed in the same crucible (for example, the raw material container A solid carbon container is placed in the upper part); a container containing solid carbon is embedded in the phosphor material; or, conversely, the solid carbon is disposed around the container filled with the phosphor material powder; The method is specifically mentioned. When a large crucible is used, it is preferable to take a method in which a container containing solid carbon is placed in the same container as the phosphor raw material and fired. In any case, it is preferable to devise so that solid carbon is not mixed in the phosphor material.

(flux)
In the firing step, it is preferable that a flux coexists in the reaction system from the viewpoint of growing good crystals. The type of the flux is not particularly limited, but examples include NH ₄ Cl, LiCl, NaCl, KCl, CsCl, CaCl ₂ , BaCl ₂ , SrCl _{2 and} other chlorides, LiF, NaF, KF, CsF, CaF ₂ and BaF _2. , Fluorides such as SrF ₂ , AlF ₃ , ZnF ₂ , and phosphates such as Li ₃ PO ₄ and SrHPO ₄ . Among these, fluoride fluxes such as SrF ₂ and ZnF ₂ are preferable. These fluxes may be used alone or in combination of two or more in any combination and ratio.

  The amount of flux used varies depending on the type of phosphor material, the material of the flux, etc., but is usually 0.01 mol% or more, more preferably 0.1 mol% or more, based on 1 mol of the produced phosphor. In general, the range is preferably 10 mol% or less, more preferably 1 mol% or less. When the amount of flux used is too small, the effect of flux does not appear, and when the amount of flux used is too large, the flux effect is saturated, or it is incorporated into the host crystal to change the emission color or cause a decrease in luminance There is.

(Primary firing and secondary firing)
The firing step may be divided into primary firing and secondary firing, and the raw material mixture obtained in the mixing step may be first fired first, and then pulverized again with a ball mill or the like, followed by secondary firing. In this case, the flux may be mixed before the primary firing or may be mixed before the secondary firing. Also, the firing conditions such as the atmosphere may be changed between primary firing and secondary firing. For example, it is preferable to perform primary firing in an oxidizing or neutral atmosphere and perform secondary firing in a reducing atmosphere.

When dividing the firing step into primary firing and secondary firing, the temperature of primary firing is usually 1000 ° C. or higher, preferably 1050 ° C. or higher, and usually 1500 ° C. or lower, preferably 1300 ° C. or lower.
The primary firing time is usually 1 hour or longer, preferably 2 hours or longer, and usually 15 hours or shorter, preferably 12 hours or shorter.
The conditions such as the temperature and time of the secondary firing are basically the same as the conditions described in the above (Baking conditions) column.

<Post-processing>
After the heat treatment in the above-described firing step, washing, drying, pulverization, classification treatment, and the like are performed as necessary.
For the pulverization treatment, for example, pulverizers listed as being usable in the raw material mixing step can be used.
The washing can be performed using, for example, water such as deionized water, an organic solvent such as ethanol, an alkaline aqueous solution such as ammonia water, and the like. In addition, for the purpose of removing the used flux, for example, an inorganic acid such as hydrochloric acid, nitric acid, sulfuric acid, or an aqueous solution of an organic acid such as acetic acid can be used. In this case, it is preferable that the phosphor is washed in an acidic aqueous solution and further washed with water.

As the degree of washing, it is preferable that the pH of the supernatant obtained by dispersing the washed phosphor in water 10 times by weight and allowing it to stand for 1 hour is neutral (about pH 7 to 9). If this pH is biased to basic or acidic, there is a possibility that the liquid medium will be adversely affected when mixed with the liquid medium described later.
The degree of washing can also be expressed by the electrical conductivity of the supernatant obtained by dispersing the washed phosphor in 10 times the weight ratio of water and allowing it to stand for 1 hour. The electrical conductivity is preferably as low as possible from the viewpoint of light emission characteristics, but in consideration of productivity, the washing treatment is usually repeated until it is 10 mS / m or less, preferably 5 mS / m or less, more preferably 4 mS / m or less. It is preferable.

  As a method for measuring electrical conductivity, phosphor particles having a specific gravity heavier than water are obtained by stirring and dispersing in water 10 times the weight of the phosphor for a predetermined time, for example, 10 minutes, and then allowing to stand for 1 hour. And the electric conductivity of the supernatant at this time is measured using an electric conductivity meter “EC METER CM-30G” manufactured by Toa Decay Co., Ltd. Although there is no restriction | limiting in particular as water used for a washing process and a measurement of electrical conductivity, Demineralized water or distilled water is preferable. Among them, those having particularly low electrical conductivity are preferable, and water of usually 0.0064 mS / m or more, usually 1 mS / m or less, preferably 0.5 mS / m or less is used. The electrical conductivity is usually measured at room temperature (about 25 ° C.).

  The classification treatment can be performed, for example, by performing water sieving or using various classifiers such as various air classifiers and vibrating sieves. In particular, when dry classification using a nylon mesh is used, a phosphor with good dispersibility having a weight median diameter of about 20 μm can be obtained.

  In addition, when manufacturing the light emitting device by the method described later using the obtained phosphor of the present invention, in order to further improve the weather resistance such as moisture resistance or the phosphor containing part of the light emitting device described later In order to improve the dispersibility with respect to the resin, a surface treatment such as coating the surface of the phosphor with a different substance may be performed as necessary.

  Examples of substances that can be made to exist on the surface of the phosphor by performing such surface treatment (hereinafter, arbitrarily referred to as “surface treatment substances”) include organic compounds, inorganic compounds, glass materials, and the like. Can be mentioned.

  Examples of the organic compound include hot-melt polymers such as acrylic resin, polycarbonate, polyamide, and polyethylene, latex, and polyorganosiloxane.

  Examples of inorganic compounds include magnesium oxide, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, tin oxide, germanium oxide, tantalum oxide, niobium oxide, vanadium oxide, boron oxide, antimony oxide, zinc oxide, yttrium oxide, oxide Examples thereof include metal oxides such as lanthanum and bismuth oxide, metal nitrides such as silicon nitride and aluminum nitride, orthophosphates such as calcium phosphate, barium phosphate, and strontium phosphate, and polyphosphates. And at least one selected from the group consisting of lithium phosphate, sodium phosphate, and potassium phosphate, and at least one selected from the group consisting of barium nitrate, calcium nitrate, strontium nitrate, barium hydrochloride, calcium hydrochloride, and strontium hydrochloride. Can also be used in combination. When barium, calcium, or strontium is present on the phosphor surface, the surface treatment can be performed using only a phosphate such as sodium phosphate.

  Examples of the glass material include borosilicate, phosphosilicate, and alkali silicate.

  These surface treatment substances may be used alone or in combination of two or more in any combination and ratio.

Examples of the presence of the phosphor surface treatment substance obtained by the above surface treatment include the following.
(I) A mode in which the surface treatment substance constitutes a continuous film and covers the phosphor surface.
(Ii) A mode in which the surface treatment substance becomes a large number of fine particles and adheres to the surface of the phosphor to coat the surface of the phosphor.

  The adhesion amount or the coating amount of the surface treatment substance on the surface of the phosphor is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.1% by weight or more, preferably 1 with respect to the weight of the phosphor. % By weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, and usually 50% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less. If the amount of the surface treatment substance with respect to the phosphor is too large, the light emission characteristics of the phosphor may be impaired. If the amount is too small, the surface coating may be incomplete, and the moisture resistance and dispersibility may not be improved.

  Further, the film thickness (layer thickness) of the surface treatment substance formed by the surface treatment is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 10 nm or more, preferably 50 nm or more, and usually 2000 nm or less, preferably Is 1000 nm or less. If this film thickness is too thick, the light emission characteristics of the phosphor may be impaired. If it is too thin, the surface coating may be incomplete, and the moisture resistance and dispersibility may not be improved.

  The surface treatment method is not particularly limited, and examples thereof include a coating method using a metal oxide (silicon oxide) as described below.

  The phosphor of the present invention is mixed in an alcohol such as ethanol and stirred, and further an alkaline aqueous solution such as ammonia water is mixed and stirred. Next, a hydrolyzable alkyl silicate such as tetraethylorthosilicate is mixed and stirred. The obtained solution is allowed to stand for 3 to 60 minutes, and then the supernatant containing silicon oxide particles that have not adhered to the phosphor surface is removed with a dropper or the like. Subsequently, after mixing alcohol, stirring, standing, and removing the supernatant several times, a surface-treated phosphor is obtained through a vacuum drying step at 120 ° C. to 150 ° C. for 10 minutes to 5 hours, for example, 2 hours.

  Other methods for surface treatment of the phosphor include, for example, a method in which spherical silicon oxide fine powder is adhered to the phosphor (JP-A-2-209998, JP-A-2-233794), and a phosphor-based silicon compound. A method of attaching a film (Japanese Patent Laid-Open No. 3-231987), a method of coating the surface of phosphor fine particles with polymer fine particles (Japanese Patent Laid-Open No. 6-314593), a phosphor with an organic material, an inorganic material, a glass material, etc. A coating method (Japanese Patent Laid-Open No. 2002-223008), a method of coating a phosphor surface by a chemical vapor reaction method (Japanese Patent Laid-Open No. 2005-82788), and a method of attaching metal compound particles (Japanese Patent Laid-Open No. 2006-2006) No. 28458) can be used.

[1-4. (Use of phosphor)
The phosphor of the present invention is suitable for various light-emitting devices (“light-emitting device of the present invention” to be described later) taking advantage of the excellent efficiency of converting visible light such as blue light from orange red to deep red. Can be used. In particular, when used in a light emitting device that emits orange-red to deep red light (hereinafter referred to as “red light-emitting device” as appropriate), a highly efficient orange-red to deep red light-emitting device can be realized. In addition, when a green phosphor, a blue phosphor, a yellow phosphor, an orange phosphor, or the like is combined with the phosphor of the present invention that is orange red or deep red, a high-performance white light emitting device can be realized. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

[2. Phosphor-containing composition
The phosphor of the present invention can be used by mixing with a liquid medium. In particular, when the phosphor of the present invention is used for applications such as a light emitting device, it is preferably used in a form dispersed in a liquid medium. The phosphor of the present invention dispersed in a liquid medium will be referred to as “the phosphor-containing composition of the present invention” as appropriate.

[2-1. (Phosphor)
There is no restriction | limiting in the kind of fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention, It can select arbitrarily from the fluorescent substance of this invention mentioned above. Moreover, the fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention may be only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
Furthermore, the phosphor-containing composition of the present invention may contain a phosphor other than the phosphor of the present invention as long as the effects of the present invention are not significantly impaired. That is, for example, one kind or two or more kinds of second phosphors described later can be contained.

[2-2. (Liquid medium)
The liquid medium used in the phosphor-containing composition of the present invention is not particularly limited as long as the performance of the phosphor is not impaired within the intended range. For example, any inorganic material and / or organic material may be used as long as it exhibits liquid properties under the desired use conditions, suitably disperses the phosphor of the present invention, and does not cause an undesirable reaction. it can.

  As the inorganic material, for example, a solution obtained by hydrolytic polymerization of a solution containing a metal alkoxide, a ceramic precursor polymer or a metal alkoxide by a sol-gel method, or a combination thereof, an inorganic material (for example, a siloxane bond) Inorganic materials having

Examples of organic materials include thermoplastic resins, thermosetting resins, and photocurable resins. Specifically, for example, methacrylic resin such as polymethylmethacrylate; styrene resin such as polystyrene and styrene-acrylonitrile copolymer; polycarbonate resin; polyester resin; phenoxy resin; butyral resin; polyvinyl alcohol; Cellulose resins such as cellulose acetate butyrate; epoxy resins; phenol resins; silicone resins.

Among these, particularly when using a phosphor for a high-power light-emitting device such as illumination, it is preferable to use a silicon-containing compound for the purpose of heat resistance and light resistance.
The silicon-containing compound refers to a compound having a silicon atom in the molecule, for example, an organic material (silicone material) such as polyorganosiloxane, an inorganic material such as silicon oxide, silicon nitride, silicon oxynitride, and borosilicate, Examples thereof include glass materials such as phosphosilicate and alkali silicate. Among these, silicone materials are preferable from the viewpoint of ease of handling.

The silicone material generally refers to an organic polymer having a siloxane bond as a main chain, and examples thereof include a compound represented by the following general formula (i) and / or a mixture thereof.
(R ¹ R ² R ³ SiO _1/2 ) _M (R ⁴ R ⁵ SiO _2/2 ) _D
(R ⁶ SiO _3/2 ) _T (SiO _4/2 ) _Q (i)

In the general formula (i), R ¹ to R ⁶ represent those selected from the group consisting of an organic functional group, a hydroxyl group, and a hydrogen atom. R ¹ to R ⁶ may be the same or different.
In the general formula (i), M, D, T, and Q are each a number that is 0 or more and less than 1, and satisfies M + D + T + Q = 1.

  When used for sealing a semiconductor light emitting device, the silicone material can be used after being sealed with a liquid silicone material and then cured by heat or light.

  When silicone materials are classified according to the mechanism of curing, silicone materials such as an addition polymerization curing type, a condensation polymerization curing type, an ultraviolet curing type, and a peroxide vulcanization type can be generally cited. Among these, addition polymerization curing type (addition type silicone resin), condensation curing type (condensation type silicone resin), and ultraviolet curing type are preferable. Hereinafter, the addition type silicone material and the condensation type silicone material will be described.

  The addition-type silicone material refers to a material in which polyorganosiloxane chains are crosslinked by organic addition bonds. A typical example is a compound having a Si—C—C—Si bond at a crosslinking point obtained by reacting vinylsilane and hydrosilane in the presence of an addition catalyst such as a Pt catalyst. As these, commercially available products can be used. Specific examples of addition polymerization curing type trade names include “LPS-1400”, “LPS-2410”, and “LPS-3400” manufactured by Shin-Etsu Chemical Co., Ltd.

On the other hand, examples of the condensation type silicone material include a compound having a Si—O—Si bond obtained by hydrolysis and polycondensation of an alkylalkoxysilane at a crosslinking point.
Specific examples include polycondensates obtained by hydrolysis and polycondensation of compounds represented by the following general formula (ii) and / or (iii) and / or oligomers thereof. In addition, only 1 type may be used for these compounds and / or its oligomer, and 2 or more types may be used together by arbitrary combinations and a ratio.

^{_{G m + X n Y 1 m}} -n ... (ii)
(In General Formula (ii), G represents at least one element selected from silicon, aluminum, zirconium, and titanium, X represents a hydrolyzable group, and Y ¹ represents a monovalent organic group. M represents one or more integers representing the valence of G, and n represents one or more integers representing the number of X groups, provided that m ≧ n.

^{_{(G s + X t Y 1}} s-t) u Y 2 ... (iii)
(In General Formula (iii), G represents at least one element selected from silicon, aluminum, zirconium, and titanium, X represents a hydrolyzable group, and Y ¹ represents a monovalent organic group. Y ² represents a u-valent organic group, s represents an integer of 1 or more representing the valence of G, t represents an integer of 1 or more and s−1 or less, and u represents 2 (It represents the integer above.)

  Further, the condensation type silicone material may contain a curing catalyst. As this curing catalyst, for example, a metal chelate compound or the like can be suitably used. The metal chelate compound preferably contains one or more of Ti, Ta, and Zr, and more preferably contains Zr. In addition, only 1 type may be used for a curing catalyst and it may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of such condensation-type silicone materials include Japanese Patent Application Nos. 2006-47274 to 47277 (for example, Japanese Patent Application Laid-Open Nos. 2007-119297 to 112975 and Japanese Patent Application No. 2007-19459) and Japanese Patent Application No. 2006-176468. The member for semiconductor light-emitting devices described in the specification is suitable.

Of the condensed silicone materials, particularly preferred materials will be described below.
Silicone materials generally have a problem of poor adhesion to semiconductor light emitting elements, substrates on which elements are arranged, packages, and the like, but as silicone materials having high adhesion, the following features [1] to A condensation type silicone material having one or more of [3] is preferred.
[1] The silicon content is 20% by weight or more.
[2] The solid Si-nuclear magnetic resonance (NMR) spectrum measured by the method described in detail later has at least one peak derived from Si in the following (a) and / or (b).
(A) A peak whose peak top position is in a region where the chemical shift is −40 ppm or more and 0 ppm or less with respect to tetramethoxysilane, and the half width of the peak is 0.3 ppm or more and 3.0 ppm or less.
(B) A peak whose peak top position is in a region where the chemical shift is −80 ppm or more and less than −40 ppm with respect to tetramethoxysilane, and the half width of the peak is 0.3 ppm or more and 5.0 ppm or less.
[3] The silanol content is 0.1% by weight or more and 10% by weight or less.

  In the present invention, among the above features [1] to [3], a silicone material having the feature [1] is preferable. More preferably, a silicone material having the above features [1] and [2] is preferable. Particularly preferably, a silicone material having all of the above features [1] to [3] is preferable. Hereinafter, the above features [1] to [3] will be described.

<Characteristic [1] (silicon content)>
The silicon content of the silicone material suitable for the present invention is usually 20% by weight or more, preferably 25% by weight or more, and more preferably 30% by weight or more. On the other hand, the upper limit is usually in the range of 47% by weight or less because the silicon content of the glass composed solely of SiO ₂ is 47% by weight.

  Note that the silicon content of the silicone-based material is calculated based on the results of performing inductively coupled plasma spectroscopy (hereinafter abbreviated as “ICP” where appropriate) using, for example, the following method. be able to.

{Measurement of silicon content}
Silicone material was baked in a platinum crucible in the air at 450 ° C. for 1 hour, then at 750 ° C. for 1 hour, and at 950 ° C. for 1.5 hours to remove the carbon component, and then a small amount of residue was obtained. Add more than 10 times the amount of sodium carbonate and heat with a burner to melt it, cool it, add demineralized water, and adjust the pH to about neutral with hydrochloric acid. ICP analysis is performed.

<Feature [2] (Solid Si-NMR spectrum)>
When a solid Si-NMR spectrum of a silicone-based material suitable for the present invention is measured, at least one peak in the peak region of (a) and / or (b) derived from a silicon atom to which a carbon atom of an organic group is directly bonded, Preferably, a plurality of peaks are observed.

When organized by chemical shift, in the silicone-based material suitable for the present invention, the half width of the peak described in (a) is generally the case of the peak described in (b) described later because molecular motion is less restricted. It is smaller, usually 3.0 ppm or less, preferably 2.0 ppm or less, and usually 0.3 ppm or more.
On the other hand, the full width at half maximum of the peak described in (b) is usually 5.0 ppm or less, preferably 4.0 ppm or less, and usually 0.3 ppm or more, preferably 0.4 ppm or more.

  If the half-value width of the peak observed in the chemical shift region is too large, the molecular motion is constrained and strain is large, cracks are likely to occur, and the member may be inferior in heat resistance and weather resistance. For example, when a large amount of tetrafunctional silane is used, or when a large internal stress is accumulated by rapid drying in the drying process, the half width range becomes larger than the above range.

  In addition, if the half width of the peak is too small, Si atoms in the environment will not be involved in siloxane crosslinking, and heat resistance is higher than substances formed mainly from siloxane bonds, such as examples where trifunctional silane remains in an uncrosslinked state. -It may be a member inferior in weather resistance.

  However, in a silicone material containing a small amount of Si component in a large amount of organic component, good heat resistance / light resistance and coating performance can be obtained even if the peak of the above-mentioned half-value range is observed at -80 ppm or more. There may not be.

  The value of the chemical shift of the silicone material suitable for the present invention can be calculated based on the results of solid Si-NMR measurement using the following method, for example. In addition, analysis of measurement data (half-width or silanol amount analysis) is performed by a method of dividing and extracting each peak by, for example, waveform separation analysis using a Gaussian function or a Lorentz function.

{Solid Si-NMR spectrum measurement and silanol content calculation}
When performing a solid Si-NMR spectrum about a silicone type material, a solid Si-NMR spectrum measurement and waveform separation analysis are performed on condition of the following. Further, from the obtained waveform data, the half width of each peak is determined for the silicone material. Also, from the ratio of the peak area derived from silanol to the total peak area, the ratio (%) of silicon atoms that are silanols in all silicon atoms is obtained, and the silanol content is determined by comparing with the silicon content analyzed separately. Ask.

{Device conditions}
Equipment: Chemmagnetics Infinity CMX-400 Nuclear Magnetic
Resonance spectrometer 29Si resonance frequency: 79.436 MHz
Probe: 7.5 mmφ CP / MAS probe Measurement temperature: room temperature Sample rotation speed: 4 kHz
Measurement method: Single pulse method
¹ H decoupling frequency: 50 kHz
29Si flip angle: 90 ° 29Si90 ° pulse width: 5.0μs
Repeat time: 600s
Integration count: 128 Observation width: 30 kHz
Broadening factor: 20Hz
Reference sample Tetramethoxysilane

  For silicone-based materials, 512 points are taken as measurement data, zero-filled to 8192 points, and Fourier transformed.

{Waveform separation analysis method}
For each peak of the spectrum after Fourier transform, optimization calculation is performed by a non-linear least square method with the center position, height, and half width of the peak shape created by Lorentz waveform and Gaussian waveform or a mixture of both as variable parameters.
In addition, the identification of a peak is AIChE Journal, 44 (5), p. Refer to 1141, 1998, etc.

<Feature [3] (silanol content)>
The silicone material suitable for the present invention has a silanol content of usually 0.1% by weight or more, preferably 0.3% by weight or more, and usually 10% by weight or less, preferably 8% by weight or less, more preferably The range is 5% by weight or less. By reducing the silanol content, the silanol-based material has excellent performance with little change over time, excellent long-term performance stability, and low moisture absorption and moisture permeability. However, since a member containing no silanol is inferior in adhesion, there exists an optimum range for the silanol content as described above.

  The silanol content of the silicone-based material is, for example, solid using the method described in the section of {Characteristic [2] (Solid Si-NMR spectrum)> {Solid Si-NMR spectrum measurement and silanol content calculation}. Si-NMR spectrum measurement is performed, and the ratio (%) of silicon atoms that are silanols in all silicon atoms is determined from the ratio of the peak area derived from silanol to the total peak area, and is compared with the separately analyzed silicon content. This can be calculated.

  In addition, since the silicone-based material suitable for the present invention contains an appropriate amount of silanol, the silanol usually bonds with hydrogen at the polar portion present on the device surface, thereby exhibiting adhesion. Examples of the polar part include a hydroxyl group and a metalloxane-bonded oxygen.

  In addition, the silicone material suitable for the present invention is usually heated in the presence of an appropriate catalyst to form a covalent bond by dehydration condensation with the hydroxyl group on the device surface, thereby exhibiting stronger adhesion. can do.

  On the other hand, if there is too much silanol, the inside of the system will thicken and it will be difficult to apply, or it will become more active and solidify before the light-boiling components volatilize by heating, leading to increased foaming and internal stress. It may occur and induce cracks.

[2-3. Liquid media and phosphor content)
The content of the phosphor and the liquid medium in the phosphor-containing composition of the present invention is arbitrary as long as the effects of the present invention are not significantly impaired, but the liquid medium is based on the entire phosphor-containing composition of the present invention. The amount is usually 50% by weight or more, preferably 75% by weight or more, and usually 99% by weight or less, preferably 95% by weight or less. Further, the phosphor is usually 1% by weight or more, preferably 5% by weight or more, and usually 50% by weight or less, preferably 25% by weight or less, based on the entire phosphor-containing composition of the present invention. When the amount of the liquid medium is large, no particular problem occurs. However, in order to obtain a desired chromaticity coordinate, color rendering index, luminous efficiency, etc. in the case of a semiconductor light emitting device, it is usually at a blending ratio as described above. It is desirable to use a liquid medium and a phosphor. On the other hand, if there is too little liquid medium, there is a possibility that it will be difficult to handle due to lack of fluidity.

  The liquid medium mainly has a role as a binder in the phosphor-containing composition of the present invention. The liquid medium may be used alone or in combination of two or more in any combination and ratio. For example, when a silicon-containing compound is used for the purpose of heat resistance, light resistance, etc., other thermosetting resins such as an epoxy resin may be contained to the extent that the durability of the silicon-containing compound is not impaired. In this case, the content of the other thermosetting resin is usually 25% by weight or less, preferably 10% by weight or less based on the total amount of the liquid medium as the binder.

[2-4. Other ingredients
The phosphor-containing composition of the present invention may contain other components in addition to the phosphor and the liquid medium as long as the effects of the present invention are not significantly impaired. Moreover, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.
For example, a dye for correcting color tone, an antioxidant, and a phosphorus-based process that can be contained in the second light-emitting body portion as necessary to form a second light-emitting body of the light-emitting device of the present invention described later. Processing / oxidation and heat stabilizers such as stabilizers, light resistance stabilizers such as ultraviolet absorbers, and silane coupling agents may be included.

[3. (Light emitting device)
Next, the light emitting device of the present invention will be described.
The light-emitting device of the present invention includes at least a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body.

[3-1. First luminous body]
The light source used in the present invention, that is, the first illuminant is not particularly limited as long as it can excite the second illuminant. For example, light having a peak wavelength in the range of 300 nm to 500 nm is emitted. Those that do are preferred. Specific examples include a light emitting diode (LED) or a laser diode (LD). Of these, GaN LEDs and LDs using GaN compound semiconductors are preferred. This is because GaN-based LEDs and LDs have significantly higher light output and external quantum efficiency than SiC-based LEDs that emit light in this region, and are extremely low power and extremely low power when combined with the phosphor of the present invention. This is because bright light emission can be obtained. For example, for a current load of 20 mA, GaN-based LEDs and LDs usually have a light emission intensity 100 times or more that of SiC-based. GaN-based LEDs and LDs preferably have an Al _X Ga _Y N light emitting layer, a GaN light emitting layer, or an In _X Ga _Y N light emitting layer. Among the GaN-based LEDs, those having an In _X Ga _Y N light-emitting layer are particularly preferable because the emission intensity is very strong, and in the GaN-based LD, the multiple quantum of the In _X Ga _Y N layer and the GaN layer is preferable. A well structure is particularly preferable because the emission intensity is very strong.

  In the above, the value of X + Y is usually a value in the range of 0.8 to 1.2. In the GaN-based LED, those in which the light emitting layer is doped with Zn or Si or those without a dopant are preferable for adjusting the light emission characteristics.

A GaN-based LED has these light-emitting layer, p-layer, n-layer, electrode, and substrate as basic components, and the light-emitting layer is an n-type and p-type Al ^X Ga ^Y N layer, GaN layer, or In ^X Those having a hetero structure sandwiched between Ga ^Y N layers and the like have high luminous efficiency, and those having a hetero structure having a quantum well structure further have high luminous efficiency and are more preferred.

[3-2. Second light emitter]
The second light emitter in the light emitting device of the present invention is a light emitter that emits visible light when irradiated with the light from the first light emitter described above, and the phosphors described later (red phosphor, orange phosphor, yellow fluorescence). Body, green phosphor, blue phosphor, etc.) depending on its use and the like.

<First phosphor (red phosphor)>
The second light emitter in the light emitting device of the present invention contains at least the phosphor of the present invention described above as a red phosphor (hereinafter referred to as “first phosphor” as appropriate). Any one of the phosphors of the present invention may be used alone, or two or more thereof may be used in any combination and ratio. In addition to the phosphor of the present invention, other one or more red phosphors may be used in combination as the first phosphor.

Examples of other red phosphors usable in the light emitting device of the present invention include a europium activated alkaline earth silicon nitride phosphor represented by (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu. , (Y, La, Gd, Lu) ₂ O ₂ S: Europium-activated rare earth oxychalcogenite phosphors represented by Eu.

  Further, an oxynitride and / or an acid containing at least one element selected from the group consisting of Ti, Zr, Hf, Nb, Ta, W, and Mo described in JP-A No. 2004-3000247 Phosphors containing sulfide and phosphors containing an oxynitride having an alpha sialon structure in which a part or all of Al element is substituted with Ga element are also available as other red colors that can be used in the light emitting device of the present invention. An example of a phosphor is given.

Other examples of other red phosphors that can be used in the light emitting device of the present invention include (La, Y) ₂ O ₂ S: Eu, Y ₂ O ₃ : Eu, (Ba, Mg) ₂ SiO ₄ : Eu, Mn, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu, Mn, Y (V, P) O ₄ : Eu, (Ca, Sr) S: Eu, YAlO ₃ : Eu, Ca ₂ Y ₈ (SiO _{2 4} ) ₆ O ₂ : Eu, LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce, (Tb, Gd) ₃ Al ₅ O ₁₂ : Ce, (Ca, Sr , Ba) ₂ Si ₅ N ₈ : Eu, (Ca, Sr, Ba) SiN ₂ : Eu, (Ca, Sr, Ba) AlSiN ₃ : Eu, (Ca, Sr, Ba) AlSiN ₃ : Ce, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Mn , (Ba ₃ Mg) Si ₂ O ₈ : Eu, Mn, 3.5MgO.0.5MgF ₂ .GeO ₂ : Mn, Eu-activated α-sialon, (Sr, Ba, Ca) ₃ SiO ₅ : Eu, Sr ₂ BaSiO ₅ : Eu, (Gd, Y, Lu, La) ₂ O ₃ : Eu, Bi, (Gd, Y, Lu, La) ₂ O ₂ S: Eu, Bi, (Gd, Y, Lu, La) VO ₄ : Eu, Bi, SrY ₂ S ₄ : Eu, Ce, CaLa ₂ S ₄ : Ce, (Ba, Sr, Ca) MgP ₂ O ₇ : Eu, Mn, (Y, Lu) ₂ WO ₆ : Eu, Mo , (Ba, Sr, Ca) _x Si _{y Nz} : Eu, Ce, (Ba, Sr, Ca, Mg) ₃ (Zn, Mg) Si ₂ O ₈ : Eu, Mn, (Sr, Ca, Ba, Mg) _{, Zn) 2 P 2 O 7} : Eu, Mn, (Ca, Sr, Ba, Mg _{10 (PO 4) 6 (F} , Cl, Br, OH): Eu, Mn, ((Y, Lu, Gd, Tb) 1-x Sc x Ce y) 2 (Ca, Mg) 1-r (Mg, Zn) _{2 + r} Si _z-q Ge _q O _{12 + δ and the} like can also be mentioned.

  Further, a red organic phosphor comprising a rare earth element ion complex having an anion such as β-diketonate, β-diketone, aromatic carboxylic acid, or Bronsted acid as a ligand, a perylene pigment (for example, dibenzo {[f , F ′]-4,4 ′, 7,7′-tetraphenyl} diindeno [1,2,3-cd: 1 ′, 2 ′, 3′-lm] perylene), anthraquinone pigments, lake pigments, Azo pigment, quinacridone pigment, anthracene pigment, isoindoline pigment, isoindolinone pigment, phthalocyanine pigment, triphenylmethane basic dye, indanthrone pigment, indophenol pigment, cyanine pigment, Dioxazine pigments and the like are also listed as other red phosphors that can be used in the light emitting device of the present invention.

  Any of the red phosphors exemplified above may be used in combination with the phosphor of the present invention, or two or more may be added in any combination and ratio.

Among the above examples, (Ca, Sr, Ba) AlSiN ₃ : Eu, (Ca, Sr, Ba) AlSiN ₃ : Ce, (La, Y) ₂ O ₂ S: Eu (hereinafter abbreviated as “LOS” as appropriate). And (Sr, Ca) AlSiN ₃ : Eu, LOS are particularly preferred as other phosphors used with the red phosphor of the present invention.

The emission peak wavelength λ _p (nm) of the first phosphor used in the light emitting device of the present invention is preferably in the range of usually 610 nm or more, especially 650 nm or more, and usually 750 nm or less, especially 700 nm or less. While this emission peak wavelength lambda _p tends to carry a too short yellowish, it tends to decrease visibility is too long, since both there is a possibility that the characteristics of the red light undesirably reduced.

  The relative intensity of the emission peak of the first phosphor used in the light emitting device of the present invention is preferably higher.

  In addition, the full width at half maximum (FWHM) of the emission peak of the first phosphor used in the light emitting device of the present invention is usually 70 nm or more, particularly 80 nm or more, and usually 120 nm or less, particularly 110 nm or less. preferable. If the full width at half maximum FWHM is too narrow, the light emission intensity may be lowered, and if it is too wide, the color purity may be lowered.

<Second phosphor>
The light-emitting device of the present invention requires phosphors of emission colors other than the above-mentioned red (green phosphor, blue phosphor, orange phosphor, yellow phosphor, etc.) as the second phosphor of the second phosphor. Depending on the content.

(Green phosphor)
Examples of the green phosphor that can be used in the light emitting device of the present invention include any phosphor as long as the effects of the present invention are not significantly impaired. The emission peak wavelength of this green phosphor is usually 500 nm or more, preferably 510 nm or more, more preferably 520 nm or more, and usually 610 nm or less, preferably 600 nm or less, more preferably 580 nm or less, more preferably 550 nm or less. It is preferable that it exists in.

Examples of the green phosphor usable in the light emitting device of the present invention include a europium-activated alkaline earth silicon oxynitride phosphor represented by (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu In addition to the europium activated alkaline earth magnesium silicate phosphor represented by (Ba, Ca, Sr) ₃ SiO ₄ : Eu, Sr ₄ Al ₁₄ O ₂₅ : Eu, (Sr, Ba) Al ₂ Si ₂ O _{8: Eu, (Ba, Mg} ) 2 SiO 4: Eu, Y 2 SiO 5: Ce, Tb, Sr 2 P 2 O 7 -Sr 2 B 2 O 5: Eu, Sr 2 Si 3 O 8 -2SrCl 2: _{Eu, Zn 2 SiO 4: Mn} , CeMgAl 11 O 19: Tb, (Ba, Sr, Ca, Mg) 2 SiO 4: Eu, Ca 2 Y 8 (SiO 4) 6 O 2: Tb, Y ₃ Al ₅ O ₁₂ : Tb, La ₃ Ga ₅ SiO ₁₄ : Tb, (Sr, Ba, Ca) Ga ₂ S ₄ : Eu, Tb, Sm, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, Ca ₃ (Sc, Mg, Na, Li) ₂ Si ₃ O ₁₂ : Ce, CaSc ₂ O ₄ : Ce, SrSi ₂ O ₂ N ₂ : Eu, (Sr, Ba, Ca ) Si ₂ O ₂ N ₂ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn, SrAl ₂ O ₄ : Eu, (La, Gd, Y) ₂ O ₂ S: Tb, LaPO ₄ : Ce, Tb, ZnS: Cu , Al, ZnS: Cu, Au, Al, Y ₂ SiO ₅ : Ce, Tb, Eu-activated β sialon, Eu-activated α sialon, (Ba, Sr, Ca) Al ₂ O ₄ : Eu, (Y, Ga , Lu, Sc, La) BO _{: Ce, Tb, Ca 8 Mg} (SiO 4) 4 Cl 2: Eu, Mn, (Ba, Sr, Ca) 2 (Mg, Zn) Si 2 O 7: Eu, (Sr, Ca, Ba) (Al, _{Ga, In) 2 S 4:} Eu, (Y, Ga, Tb, La, Sm, Pr, Lu) 3 (Al, Ga) 5 O 12: Ce, (Ca, Sr) 8 (Mg, Zn) (SiO ₄ ) ₄ Cl ₂ : Eu, Mn, Na ₂ Gd ₂ B ₂ O ₇ : Ce, Tb, (Ba, Sr) ₂ (Ca, Mg, Zn) B ₂ O ₆ : K, Ce, Tb, etc. . Any one of these may be used alone, or two or more may be used in any combination and ratio.

(Blue phosphor)
The blue phosphor that can be used in the light emitting device of the present invention preferably has a fluorescence center wavelength of usually 420 nm or more, preferably 440 nm or more, and usually 500 nm or less, preferably 470 nm or less.

Examples of blue phosphors that can be used in the light emitting device of the present invention include europium activated barium magnesium aluminate phosphors represented by BaMgAl ₁₀ O ₁₇ : Eu, (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ Europium-activated calcium halophosphate phosphor represented by Cl: Eu, Ca, Sr, Ba) ₂ B ₅ O ₉ Cl: Europium-activated alkaline earth chloroborate phosphor represented by Eu, (Sr, Ca, Ba) Examples include europium activated alkaline earth aluminate phosphors represented by) Al ₂ O ₄ : Eu or (Sr, Ca, Ba) ₄ Al ₁₄ O ₂₅ : Eu.

Other examples of blue phosphors that can be used in the light emitting device of the present invention include Sr ₂ P ₂ O ₇ : Sn, Sr ₄ Al ₁₄ O ₂₅ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, SrGa ₂ S ₄ : Ce, CaGa ₂ S ₄ : Ce, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, Mn, (Sr, Ca, Ba, Mg) ₁₀ (PO _{4 ) 6 Cl 2: Eu, BaAl} 2 Si 2 O 8: Eu, BaMgAl 10 O 17: Eu, Tb, Sm, (Sr, Ba) 3 MgSi 2 O 8: Eu, Sr 2 P 2 O 7: Eu, ZnS _{: Ag, ZnS: Ag, Al} , Y 2 SiO 5: Ce, CaWO 4, (Ba, Sr, Ca) 5 (PO 4) 3 (Cl, F, Br, OH): Eu, Mn, Sb, (Ba _{Sr, Ca) BPO 5: Eu} , Mn, (Sr, Ca) 10 (PO 4) 6 · nB 2 O 3: Eu, 2SrO · 0.84P 2 O 5 · 0.16B 2 O 3: Eu, Sr 2 Examples thereof include Si ₃ O ₈ .2SrCl ₂ : Eu, BaAl ₈ O ₁₃ : Eu, (Ba, Ca, Mg) ₂ SiO ₄ : Eu, and the like.

  In addition, organic phosphors such as naphthalic acid imide-based, benzoxazole-based, styryl-based, coumarin-based, pyralizone-based, triazole-based compound fluorescent dyes, thulium complexes, etc. Take as an example.

  Any one of the blue phosphors exemplified above may be used alone, or two or more may be used in any combination and ratio.

Among the above examples, as the blue phosphor, BaMgAl ₁₀ O ₁₇ : Eu (hereinafter abbreviated as “BAM” as appropriate), (Ba, Ca, Mg) ₂ SiO ₄ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu is preferred, and BaMgAl ₁₀ O ₁₇ : Eu is particularly preferred.

(Orange phosphor)
The orange phosphor that can be used in the light emitting device of the present invention preferably has a fluorescent central wavelength in the range of usually 580 nm or more, preferably 590 nm or more, and usually 620 nm or less, preferably 610 nm or less.

Examples of orange phosphors that can be used in the light emitting device of the present invention include (Sr, Ba) ₃ SiO ₅ : Eu, (Sr, Mg) ₃ (PO ₄ ) ₂ : Sn ²⁺ , SrCaAlSiN ₃ : Eu, and the like. It is done.

  Any one of the orange phosphors exemplified above may be used alone, or two or more may be used in any combination and ratio.

(Yellow phosphor)
As the yellow phosphor that can be used in the light emitting device of the present invention, any one can be used as long as the effects of the present invention are not significantly impaired. The emission peak wavelength of this yellow phosphor is preferably in the wavelength range of usually 530 nm or more, preferably 540 nm or more, more preferably 550 nm or more, and usually 620 nm or less, preferably 600 nm or less, more preferably 580 nm or less. is there.

Examples of such yellow phosphors include various oxide-based, nitride-based, oxynitride-based, sulfide-based, and oxysulfide-based phosphors.
In particular, RE ₃ M ₅ O ₁₂ : Ce (where RE represents at least one element selected from the group consisting of Y, Tb, Gd, Lu, and Sm, and M represents Al, Ga, and Sc. And M ^a ₃ M ^b ₂ M ^c ₃ O ₁₂ : Ce (where M ^a is a divalent metal element and M ^b is a trivalent metal element) , ^{M c} is garnet phosphor having a garnet structure represented by the representative) like a tetravalent metallic ^{_{element, AE 2 M d O 4:}} . Eu ( where, AE is, Ba, Sr, Ca, Mg , And at least one element selected from the group consisting of Zn, and M ^d represents Si and / or Ge)), etc., and constituent elements of the phosphors of these systems An oxynitride phosphor obtained by substituting a part of oxygen in nitrogen with nitrogen, EAlSiN _3: Ce (., Where, AE is, Ba, Sr, Ca, Mg and represents at least one element selected from the group consisting of Zn) of the nitride-based fluorescent material or the like having a CaAlSiN ₃ structure, such as Ce And the phosphor activated in step (b).

In addition, examples of yellow phosphors include sulfide-based fluorescence such as CaGa ₂ S ₄ : Eu, (Ca, Sr) Ga ₂ S ₄ : Eu, (Ca, Sr) (Ga, Al) ₂ S ₄ : Eu. It is also possible to use a phosphor activated by Eu, such as an oxynitride phosphor having a SiAlON structure such as a body, Cax (Si, Al) ₁₂ (O, N) ₁₆ : Eu.

  Examples of the yellow phosphor include fluorescent dyes such as brilliantsulfoflavine FF (Colour Index Number 56205), basic yellow HG (Colour Index Number 46040), eosine (Colour Index Number 45380), rhodamine 6G (Colour Index Number 45160), etc. It is also possible to use.

  Any one of the yellow phosphors exemplified above may be used alone, or two or more may be used in any combination and ratio.

  In addition to the above-described red, green, blue, orange, and yellow phosphors, phosphors such as blue-green in the middle can be used in combination as needed.

<Preferable combination of first phosphor, first phosphor and second phosphor>
When the light emitting device of the present invention is configured as a white light emitting device, the phosphors used for the second light emitter may be appropriately combined so that desired white light can be obtained. Specifically, examples of preferable combinations of the first light emitter, the first phosphor, and the second phosphor in the case where the light emitting device of the present invention is configured as a white light emitting device include the following: (I) and the combination of (ii) are mentioned.

(I) A blue light emitter (blue LED or the like) is used as the first light emitter, the light of the blue LED is used as it is as the blue component, and a red phosphor (in accordance with the present invention) is used as the second light emitter. Phosphor and the like) and green phosphor.
That is, as the first light emitter, one having an emission peak in a wavelength range of 420 nm or more and 500 nm or less is used, and as the second light emitter, the phosphor of the present invention as the first phosphor and the second fluorescence At least one phosphor having a light emission peak in a wavelength range of 500 nm to 610 nm as a body is used.
In this case, the green phosphor is preferably one type or two or more types of green phosphors selected from the group consisting of the green phosphors exemplified in the section of the phosphor.

(Ii) A blue light emitter (blue LED or the like) is used as the first light emitter, the light of the blue LED is used as it is as the blue component, and a red phosphor (of the present invention) is used as the second light emitter. Phosphor, etc.), green phosphor, yellow phosphor or orange phosphor.
In this case, as the green phosphor, the green phosphor, the yellow phosphor, and the orange phosphor, one or more phosphors selected from the group consisting of the phosphors exemplified in the section of the phosphor are preferable.

(Iii) A near-ultraviolet illuminant (near-ultraviolet LED or the like) is used as the first illuminant, and a red phosphor (such as the phosphor of the present invention), a blue phosphor or a green fluorescence is used as the phosphor of the second illuminant. Use the body.
That is, as the first light emitter, one having an emission peak in the wavelength range of 300 nm to 420 nm is used, and as the second light emitter, the phosphor of the present invention as the first phosphor and the second fluorescence At least one type of phosphor having an emission peak in a wavelength range of 420 nm to 500 nm and at least one type of phosphor having an emission peak in a wavelength range of 500 nm to 610 nm are used.
In this case, as the green phosphor, the green phosphor, and the blue phosphor, one or more phosphors selected from the group consisting of the phosphors exemplified in the section of the phosphor are preferable.

(Iv) A near-ultraviolet illuminant (near-ultraviolet LED or the like) is used as the first illuminant, and a red phosphor (such as the phosphor of the present invention), a blue phosphor, or green fluorescence as the phosphor of the second illuminant. Body, yellow phosphor or orange phosphor.
In this case, as the green phosphor, the blue phosphor, the green phosphor, the yellow phosphor, and the orange phosphor, one kind or two or more kinds of phosphors selected from the group consisting of the phosphors exemplified in the section of the phosphor. Is preferred.

Among the examples of the second phosphor described above, the green phosphor combined with the red phosphor of the present invention includes CaSc ₂ O ₄ : Ce, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu, and Ca. ₃ (Sc, Mg, Na, Li) ₂ Si ₃ O ₁₂ : Ce is preferably one or more selected from the group consisting of Ce, and the orange phosphor is Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, And one or more selected from the group consisting of (Sr, Ba) ₃ SiO ₅ : Eu.

For example, when producing an illuminating device, the red phosphor of the present invention, and CaSc ₂ O ₄ : Ce and Ca ₃ (Sc, Mg, Na, Li) ₂ Si ₃ O ₁₂ : Ce as green phosphors. An illuminating device having excellent color rendering properties can be obtained by combining one or more selected from the group. On the other hand, when used as a light source for backlights of liquid crystal displays, the red phosphor of the present invention and (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu, (Ca, Sr, Ba) as green phosphors. ₂ Ga ₂ S ₄ : Eu and Eu ²⁺ added β sialon (Si ₆ -Z Al _z N ₈ -z O _z ; z = 0 to 4.2) selected from the group consisting of one or more Can be used to obtain a backlight light source excellent in color reproducibility.

<Physical properties of first phosphor and second phosphor>
The weight median diameter of the first phosphor (red phosphor) and the second phosphor (green phosphor, blue phosphor, orange phosphor, yellow phosphor, etc.) used in the light emitting device of the present invention is usually It is preferably in the range of 10 μm or more, especially 15 μm or more, and usually 30 μm or less, especially 20 μm or less. When the weight median diameter is too small, the luminance is lowered and the phosphor particles tend to aggregate. On the other hand, when the weight median diameter is too large, there is a tendency for coating unevenness and blockage of a dispenser to occur.

<Phosphor content>
The first light emitter is mainly composed of the first phosphor, the second phosphor used as necessary, and the sealing material using the liquid medium described above. The content of the phosphor in the second light emitter is not particularly limited, but is usually 0.01 to 100 parts by weight, preferably 0.1 to 80 parts by weight with respect to 100 parts by weight of the sealing material. Parts, preferably 1 to 60 parts by weight.
In addition, the second illuminant portion is provided with light resistance such as dyes for color tone correction, antioxidants, processing stabilizers such as phosphorus processing stabilizers, heat stabilizers, ultraviolet absorbers, etc. A stabilizer and a silane coupling agent may be included.

[3-3. Configuration of light emitting device
The other configurations of the light emitting device of the present invention are not particularly limited as long as the first light emitting body and the second light emitting body described above are provided. Usually, the first light emitting body described above is formed on an appropriate frame. And a second light emitter. At this time, the second light emitter is excited by the light emission of the first light emitter to emit light, and the light emission of the first light emitter and / or the light emission of the second light emitter is extracted outside. Will be arranged as follows.

  In addition to the first light emitter, the second light emitter, and the frame described above, a sealing material is usually used. Specifically, the sealing material is formed by dispersing the first phosphor and / or the second phosphor to form a second light emitter, or the first light emitter and the second light emitter. It is also used for the purpose of bonding between frames.

  In the light emitting device of the present invention as a white light emitting device, for example, a phosphor-containing layer containing a mixture of a red phosphor, a blue phosphor and a green phosphor may be disposed on a light source. In this case, the red phosphor does not necessarily have to be mixed in the same layer as the blue phosphor and the green phosphor. For example, the red phosphor is placed on the layer containing the blue phosphor and the green phosphor. The layer to contain may be laminated | stacked.

  In the light emitting device of the present invention, the phosphor-containing layer can be provided above the light source. The phosphor-containing layer can be provided as a contact layer between the light source and the sealing material part, as a coating layer outside the sealing material part, or as a coating layer inside the outer cap. Moreover, the form which contained the fluorescent substance in the sealing material can also be taken.

  As a sealing material used, a thermoplastic resin, a thermosetting resin, a photocurable resin, etc. are mentioned normally. Specifically, for example, methacrylic resin such as polymethylmethacrylate; styrene resin such as polystyrene and styrene-acrylonitrile copolymer; polycarbonate resin; polyester resin; phenoxy resin; butyral resin; polyvinyl alcohol; Cellulose resins such as cellulose acetate butyrate; epoxy resins; phenol resins; silicone resins. Further, an inorganic material such as a siloxane bond formed by solidifying a solution obtained by hydrolytic polymerization of a solution containing an inorganic material such as a metal alkoxide, ceramic precursor polymer or metal alkoxide by a sol-gel method, or a combination thereof. An inorganic material can be used.

[3-4. Embodiment of Light Emitting Device]
Hereinafter, the light-emitting device of the present invention will be described in more detail with reference to specific embodiments. However, the present invention is not limited to the following embodiments, and does not depart from the gist of the present invention. It can be implemented with arbitrary modifications.

  FIG. 1 is a diagram schematically showing a configuration of a light emitting device according to an embodiment of the present invention. The light emitting device 1 of the present embodiment absorbs a part of light emitted from the frame 2, a blue LED (first light emitter) 3 that is a light source, and the blue LED 3, and emits light having a wavelength different from that. It comprises a phosphor-containing part (second light emitter) 4.

  The frame 2 is a metal base for holding the blue LED 3 and the phosphor-containing portion 4. On the upper surface of the frame 2, a trapezoidal concave section (dent) 2A having an opening on the upper side in FIG. Thereby, since the frame 2 has a cup shape, the light emitted from the light emitting device 1 can have directivity, and the emitted light can be used effectively. Further, the inner surface of the concave portion 2A of the frame 2 is enhanced in the reflectance of light in the entire visible light region by metal plating such as silver, so that the light hitting the inner surface of the concave portion 2A of the frame 2 can also be emitted. Can be discharged in a predetermined direction.

  A blue LED 3 is installed as a light source at the bottom of the recess 2 </ b> A of the frame 2. The blue LED 3 is an LED that emits blue light when supplied with electric power. Part of the blue light emitted from the blue LED 3 is absorbed as excitation light by the luminescent material (phosphor) in the phosphor-containing portion 4, and another part is directed from the light emitting device 1 in a predetermined direction. To be released.

  The blue LED 3 is installed at the bottom of the recess 2A of the frame 2 as described above. Here, the frame 2 and the blue LED 3 are bonded by a silver paste (a mixture of silver particles in an adhesive) 5. Thus, the blue LED 3 is installed on the frame 2. Further, the silver paste 5 also plays a role of efficiently radiating heat generated in the blue LED 3 to the frame 2.

  Further, a gold wire 6 for supplying power to the blue LED 3 is attached to the frame 2. That is, the electrode (not shown) provided on the upper surface of the blue LED 3 is connected by wire bonding using the wire 6. When the wire 6 is energized, power is supplied to the blue LED 3. It emits blue light. One or a plurality of wires 6 are attached in accordance with the structure of the blue LED 3.

  Further, the concave portion 2A of the frame 2 is provided with a phosphor-containing portion 4 that absorbs part of the light emitted from the blue LED 3 and emits light having a different wavelength. The phosphor-containing part 4 is formed of a phosphor and a transparent resin (sealing material). The phosphor is a substance that is excited by blue light emitted from the blue LED 3 and emits light having a wavelength longer than that of the blue light. The phosphor constituting the phosphor-containing portion 4 may be a single type or a mixture of a plurality of colors, and the sum of the light emitted from the blue LED 3 and the light emitted from the phosphor-containing portion 4 is a desired color. Choose to be. The color is not limited to white, but may be yellow, orange, pink, purple, blue-green, or the like. Further, it may be an intermediate color between these colors and white. Further, the transparent resin is a sealing material for the phosphor-containing portion 4, and here, the above-described sealing material is used.

  The mold unit 7 functions as a lens for protecting the blue LED 3, the phosphor-containing unit 4, the wire 6 and the like from the outside and controlling the light distribution characteristics. Silicone resin can be mainly used for the mold part 7.

[3-5. Application of light emitting device)
The use of the light-emitting device of the present invention is not particularly limited, and can be used in various fields where ordinary light-emitting devices are used. However, since the color rendering property is high, among others, as a light source for lighting devices and image display devices. In particular, it is preferably used.

<Lighting device>
When the light-emitting device of the present invention is applied to a lighting device, the above-described light-emitting device may be appropriately incorporated into a known lighting device. For example, as shown in FIG. 2, a surface emitting illumination device 11 incorporating the above-described light emitting device 1 can be cited.

  FIG. 2 is a cross-sectional view schematically showing an embodiment of the illumination device of the present invention. As shown in FIG. 2, the surface-emitting illumination device has a large number of light-emitting devices 13 (on the light-emitting device 1 described above) on the bottom surface of a rectangular holding case 12 whose inner surface is light-opaque such as a white smooth surface. Is provided with a power source and a circuit (not shown) for driving the light-emitting device 13 on the outside, and a milky white acrylic plate or the like is provided at a position corresponding to the lid portion of the holding case 12. The diffusion plate 14 is fixed for uniform light emission.

  Then, the surface-emitting illumination device 11 is driven to emit light by applying a voltage to the excitation light source (first light emitter) of the light-emitting device 13, and a part of the light emission is converted to the phosphor-containing portion (first The phosphor in the phosphor-containing resin part as the second phosphor) absorbs and emits visible light, while light emission with high color rendering is obtained by color mixing with blue light or the like not absorbed by the phosphor. The light passes through the diffusion plate 14 and is emitted upward in the drawing, and illumination light with uniform brightness is obtained within the surface of the diffusion plate 14 of the holding case 12.

<Image display device>
When the light emitting device of the present invention is used as a light source of an image display device, the specific configuration of the image display device is not limited, but it is preferably used with a color filter. For example, when the image display device is a color image display device using color liquid crystal display elements, the light emitting device is used as a backlight, a light shutter using liquid crystal, and a color filter having red, green, and blue pixels; By combining these, an image display device can be formed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.

[Measurement method of physical properties]
The physical property values of the phosphors obtained in Examples and Comparative Examples described later can be measured and calculated by the following methods.

{Luminescent characteristics}
<Relative emission peak intensity>
First, at room temperature (25 ° C.), an emission spectrum was obtained using a 150 W xenon lamp as an excitation light source and a fluorescence measuring apparatus (manufactured by JASCO Corporation) equipped with a multichannel CCD detector C7041 (manufactured by Hamamatsu Photonics) as a spectrum measuring apparatus. It was measured.
More specifically, the light from the excitation light source was passed through a diffraction grating spectrometer having a focal length of 10 cm, and only the excitation light having a wavelength of 455 nm was irradiated to the phosphor through the optical fiber. The light generated from the phosphor by the irradiation of excitation light is dispersed by a diffraction grating spectroscope having a focal length of 25 cm, the emission intensity of each wavelength is measured by a spectrum measuring device in a wavelength range of 300 nm to 800 nm, and a personal computer is used. An emission spectrum was obtained through signal processing such as sensitivity correction.
The relative emission peak intensity is a range obtained by removing the excitation wavelength region from the emission spectrum in the visible region obtained by the above method, and the relative emission peak of YAG phosphor (product number: P46-Y3) manufactured by Kasei Optonix Co., Ltd. The intensity was calculated as a relative value with 100%.

<Half width of emission peak>
The half width of the emission peak (hereinafter sometimes referred to as “half width”) was calculated from the emission spectrum obtained by the above method.

<Chromaticity coordinates>
The chromaticity coordinates of the x, y color system (CIE 1931 color system) are based on the JIS Z8724 method according to JIS Z8724 from the data in the wavelength region of the emission spectrum from 480 nm to 800 nm (when the excitation wavelength is 455 nm). The chromaticity coordinates x and y in the prescribed XYZ color system were calculated.

<Emission spectrum>
The emission spectrum was measured at room temperature (25 ° C.) using a fluorescence spectrophotometer F-4500 manufactured by Hitachi. More specifically, an emission spectrum in the wavelength range of 470 nm to 800 nm was obtained by irradiating excitation light of 465 nm.

<Excitation spectrum>
The excitation spectrum was measured using a fluorescence spectrophotometer F-4500 manufactured by Hitachi, Ltd. at room temperature (25 ° C.). More specifically, an excitation spectrum within a wavelength range of 200 nm to 600 nm was obtained using the emission peak wavelength of each phosphor as a detection wavelength.

{Quantum efficiency}
The absorption efficiency αq, internal quantum efficiency ηi, and external quantum efficiency ηo of the phosphor were determined as follows.
First, the phosphor sample to be measured was packed in a cell with a sufficiently smooth surface so that the measurement accuracy was maintained, and was attached to an integrating sphere.

  An Xe lamp was used as an emission source for exciting the phosphor sample, and adjustment was performed using a monochromator (diffraction grating spectrometer) so as to obtain monochromatic light having an emission peak wavelength of 455 nm.

  The phosphor sample to be measured was irradiated with light from the light emission source whose emission peak wavelength was adjusted, and a spectrum including light emission (fluorescence) and reflected light was measured with a spectrometer (MCPD7000 manufactured by Otsuka Electronics Co., Ltd.). .

<Absorption efficiency α _q >
First, the absorption efficiency α _q was determined. The absorption efficiency α _q was calculated as a value obtained by dividing the number of photons N _abs of excitation light absorbed by the phosphor sample by the total number of photons N of excitation light.
The specific calculation procedure is as follows.

First, the total photon number N of the latter excitation light was obtained as follows.
That is, a material having a reflectance R of approximately 100% with respect to excitation light, for example, a white reflector such as “Spectralon” manufactured by Labsphere (having a reflectance R of 98% with respect to 455 nm excitation light) is used as a measurement target. The sample was attached to the above-described light collecting device in the same arrangement as the phosphor sample, and the reflection spectrum was measured using the spectroscopic measurement device (this reflection spectrum is hereinafter referred to as “I _ref (λ)”).

From this reflection spectrum I _ref (λ), a numerical value represented by the following (formula I) was obtained. The integration interval of the following (formula I) was set to 440 nm to 470 nm. The numerical value represented by the following (formula I) is proportional to the total photon number N of the excitation light.

Moreover, the numerical value represented by the following (formula II) was calculated | required from the reflection spectrum I ((lambda)) when the fluorescent substance sample used as the measuring object of absorption efficiency (alpha) _q was attached to the condensing apparatus. In addition, the integration interval of the following (formula II) was made the same as the integration interval defined by the above (formula I). The numerical value obtained by the following (formula II) is proportional to the number of photons _Nabs of the excitation light absorbed by the phosphor sample.

From the above, the absorption efficiency α _q was calculated by the following equation.
Absorption efficiency α _q = N _abs / N = (Formula II) / (Formula I)

<Internal quantum efficiency η _i >
The internal quantum efficiency η _i was calculated as a value obtained by dividing the number of photons N _PL derived from the fluorescence phenomenon by the number of photons N _abs absorbed by the phosphor sample.

From the above I (λ), a numerical value represented by the following formula (III) was obtained. In addition, the integration interval of the following (formula III) was 470 nm-780 nm. Figures are calculated by the following (Formula III) is proportional to the number N _PL of photons originating from the fluorescence phenomenon.

From the above, the internal quantum efficiency η _i was calculated by the following equation.
η _i = (Formula III) / (Formula II)

[Example 1]
The following raw materials were weighed and mixed well in an agate mortar so that the molar ratio of Sr, Sc, and Eu was 1: 2: 0.01.
SrCO ₃ : 1.023 g
Sc ₂ O ₃ : 0.960 g
Eu ₂ O ₃ : 0.012 g

The obtained raw material mixture is put in an alumina crucible, granular activated carbon (carbon) is placed on the mixture, and a temperature increase rate of 5 ° C./in a hydrogen-containing nitrogen gas (nitrogen: hydrogen = 96: 4 (volume ratio)) atmosphere. The temperature was raised to 1500 ° C. in minutes, and heating was performed at 1500 ° C. (maximum temperature reached) for 3 hours.
The obtained fired product was pulverized using an alumina mortar. When the obtained powder was irradiated with blue light or ultraviolet light, it showed red light emission. Therefore, it can be said that the obtained powder is a phosphor.
A powder X-ray diffraction (XRD) pattern of the obtained phosphor powder is shown in FIG. The XRD pattern of the obtained phosphor powder is No. in the standard chart of powder X-ray diffraction (JCPDS-ICDD-PDF, hereinafter abbreviated as PDF). It almost coincided with the standard pattern of SrSc ₂ O ₄ of 20-1213 (FIG. 3B). Thereby, it was found that the obtained phosphor powder was a SrSc ₂ O ₄ : Eu phosphor containing about 0.01 mol of Eu per 1 mol of SrSc ₂ O ₄ . Here, it is considered that most of Eu in the SrSc ₂ O ₄ : Eu phosphor takes a divalent state and substitutes the Sr position.

Moreover, the emission spectrum and excitation spectrum of this SrSc ₂ O ₄ : Eu phosphor are shown in FIG.
It was found that this SrSc ₂ O ₄ : Eu phosphor absorbs blue light and emits deep red fluorescence having a peak at 693 nm. It can also be seen that this SrSc ₂ O ₄ : Eu phosphor can be excited by light in the wavelength range of 250 nm to 400 nm and light in the wavelength range of 430 nm to 600 nm.
One feature of the phosphor of the present invention is that it can be excited by visible light, but it can also be excited by light in the ultraviolet or near-ultraviolet region. Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.

[Example 2]
The phosphor of Example 2 was manufactured under the same conditions as in Example 1 except that the heating temperature was 1450 ° C. Since the emission intensity of the phosphor of Example 2 is lower than that of the phosphor of Example 1, it can be seen that a higher heating temperature tends to improve the emission intensity, which is preferable. Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.

[Example 3]
The phosphor of Example 3 was obtained by manufacturing under the same conditions as in Example 1 except that the phosphor raw material preparation composition was set to the ratio shown in Table 1. The phosphor of Example 3 is Sr (Sc _1.6 , Lu _0.4 ) O ₄ : Eu (prepared composition) containing Lu. However, in all cases, by-products coexisted instead of a single phase of the phosphor having this composition ratio.

Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
Moreover, the emission spectrum and excitation spectrum of the phosphor of Example 3 are shown in FIG.
The phosphor of Example 3 was found to absorb blue light and emit deep red fluorescence having a peak at 675 nm. Moreover, when Example 1 and Example 3 are compared, it turns out that the light emission peak wavelength shifts to the short wavelength side by mixing Lu.

[Example 4]
The phosphor of Example 4 was obtained by manufacturing under the same conditions as in Example 1 except that the phosphor blending raw material composition was set to the ratio shown in Table 1. The phosphor of Example 4 is Sr (Sc _1.6 , Al _0.4 ) O ₄ : Eu (prepared composition) containing Al. However, by-products coexisted instead of a single phase having this composition ratio.
The phosphor of Example 4 was found to absorb blue light and emit deep red fluorescence having a peak at 685 nm to 690 nm.

[Examples 5 to 7]
The phosphors of Examples 5 to 7 were obtained by manufacturing under the same conditions as in Example 1 except that the phosphor raw material preparation composition was changed to the ratio shown in Table 1. The phosphors of Examples 5 to 7 are prepared by replacing a part of Sr in Example 1 with Ca or Ba in the preparation composition.
Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. It can be seen that the emission peak wavelength tends to shift to the longer wavelength side when the proportion of Ca in the M ¹ element in the formula [I] increases. In addition, the emission intensity decreased due to the addition of Ba.
It can be seen that the larger the proportion of Sr in the M ¹ element, the higher the emission intensity, which is preferable.

[Example 8]
As shown in Table 1, the phosphor of Example 8 was obtained under the same conditions as in Example 1 except that the addition amount of Eu as the luminescent center ion was changed. As shown in Table 1, the prepared raw material composition of Example 8 was Sr: Sc: Ey = 0.97: 2: 0.03.
Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. As compared with Example 1, it can be seen that the emission intensity tends to decrease when the Eu amount is increased.

[Examples 9 to 16]
The following raw materials were weighed so that the molar ratio of Sr, Sc, Lu, Eu was 1: 1.8: 0.2: 0.01, and the additives (flux) shown in Table 1 were added. (However, in Example 9, no flux was added) and mixed well in an agate mortar.
SrCO ₃ : 1.414 g
Sc ₂ O ₃ : 1.189 g
Lu ₂ O ₃ : 0.381 g
Eu ₂ O ₃ : 0.017 g
Additives: types and molar ratios shown in Table 1 (molar ratio is a molar ratio to SrCO ₃ )
The types and amounts of additives that can be placed in each example are as follows. The amount added was the molar ratio with respect to SrCO ₃ .
Example 9: No additive (comparative object)
Example 10: SrCl ₂ 0.2 mol of _Li 3 PO ₄ 0.1 mol Example 11: SrCl ₂ 0.2 mol Example 12: SrCl ₂ 0.1 mol Example 13: a SrF ₂ 0.1 mol Example 14: 0.1 mol of ZnF ₂ Example 15: 0.1 mol of Li ₃ PO ₄ Example 16: 0.1 mol of SrHPO ₄

  The obtained raw material mixture is put in an alumina crucible, and granular activated carbon is put on it. In a hydrogen-containing nitrogen gas (nitrogen: hydrogen = 96: 4 (volume ratio)) atmosphere, the heating rate is 5 ° C./min. The temperature was raised to 1450 ° C. and heated at 1450 ° C. (maximum temperature reached) for 2 hours. The obtained fired product was pulverized with an alumina mortar to obtain phosphors of Examples 9 to 16.

Table 1 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. From these results, it can be seen that the emission intensity increases by using the additive.
Further, when the additive is used, the amount of by-products generated is reduced as compared with the case where the additive is not used. Further, as can be seen from the SEM photographs (FIGS. 5A to 5H), the use of the additive tends to increase the particle size. Among them, the effect of increasing the particle size of SrF ₂ and ZnF ₂ is large, and these are considered to be fluxes suitable for the synthesis of this phosphor. SrCl ₂ , Li ₃ PO ₄ , and SrHPO ₄ were less effective as fluxes than SrF ₂ and ZnF ₂ , but these also improved the emission intensity and the by-product phase if the addition amount was optimized. Can be expected to decrease.

[Examples 17 to 23]
As shown in Table 2, phosphors of Examples 17 to 23 were obtained by manufacturing under the same conditions as in Example 13 except that the phosphor composition (Sc / Lu ratio) was changed. That is, in the composition formula Sr (Sc _2-x , Lu _x ) O ₄ : Eu, the value of x was changed as 0 ≦ x ≦ 2.
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. The phosphor having the maximum emission intensity (Example 20) had an emission peak wavelength of 669 nm and a half-value width of 92 nm. Note that the emission intensity of the phosphor of Example 19 (Sc / Lu = 8/2) is lower than that of the other examples and shows a different tendency because the crucible lid was displaced during firing. It is thought that. Moreover, the emission spectrum of 455 nm excitation of the fluorescent substance of Example 17, 20, and 23 is shown in FIG.
From these results, it can be seen that the proportion of Lu in the M ² element in the formula [I] increases and the emission peak wavelength shifts to the short wavelength side. It can also be seen that the emission intensity shows a maximum value in the vicinity where the molar ratio of Sc to Lu (Sc / Lu) is 7/3.

[Example 24]
As shown in Table 2, phosphors were produced under the same conditions as in Example 17 except that ZnF ₂ was added instead of SrF ₂ .
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. Phosphors emitting red light at a similarly blue excitation as in Example 17 using the SrF ₂ was obtained.

[Example 25]
As shown in Table 2, except that the addition of ZnF ₂ instead of SrF _2, to produce a phosphor under the same conditions as in Example 23.
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition. Phosphors emitting red light at a similarly blue excitation as in Example 23 using the SrF ₂ was obtained.

When Examples 17 and 24 and Examples 23 and 25 are compared, it is found that SrF ₂ is more preferable than ZnF ₂ as the flux in terms of emission intensity.

[Examples 26 to 28]
A phosphor was produced under the same conditions as in Example 13 except that the phosphor raw material preparation composition was set to the ratio shown in Table 2, and the phosphors of Examples 26 to 28 were obtained. Example 26 is a phosphor to which Y is added, that is, Sr (Sc, Y) ₂ O ₄ : Eu. Examples 27 and 28 are phosphors containing Sr, Ca, and Lu in the base crystal, _{That, (Sr, Ca) Lu 2} O 4: is Eu.
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.

[Examples 29 to 32]
As shown in Table 2, phosphors of Examples 29 to 32 were obtained under the same conditions as in Example 17 except that the addition amount of Eu was changed.
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
Among Examples 29 to 32, since the emission intensity of Example 30 (Eu addition amount 0.3 mol%) was the highest, the ratio of Sc in the M ² element in the formula [I] was 100%. In this case, the optimum addition amount of Eu is found to be about 0.3 mol% per mole of the parent SrSc ₂ O _{4, and} a preferable range of the addition amount of Eu is as follows per mole of SrSc ₂ O _4. It is thought that it is 0.3 mol%-0.8 mol%. It can also be seen that the smaller the added amount of Eu, the more the emission peak wavelength tends to shift to the short wavelength side.

[Examples 33 to 36]
As shown in Table 2, the phosphors of Examples 33 to 36 were obtained under the same conditions as in Example 20 except that the addition amount of Eu was changed.
Table 2 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
Among Examples 33 to 36, the emission intensity of Example 33 (Eu addition amount: 0.5 mol%) is the highest, and it is considered that the emission intensity tends to increase as the Eu addition amount increases. The optimum addition amount of Eu when Sc and Lu are contained as the M ² element in the formula [I] is 0.5 mol% to 1 mol of the base Sr (Sc _0.7 , Lu _0.3 ) ₂ O _4. It turns out that it is about 1.0 mol%. It can also be seen that the emission peak wavelength tends to shift to the shorter wavelength side as the Eu amount is smaller.

[Comparative Example 1]
Heating was performed under the same conditions as in Example 1 except that no granular activated carbon was allowed to coexist. The obtained fired product was pulverized in an alumina mortar to obtain a phosphor.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
The obtained phosphor had very weak red emission due to blue excitation derived from Eu ²⁺ . It is presumed that Eu was not sufficiently reduced from trivalent to divalent because no granular activated carbon was added in the heating step. In addition, in the case of ultraviolet excitation with a short wavelength such as 254 nm, line-like emission derived from Eu ³⁺ was observed although it was very weak. FIG. 7 shows an emission spectrum of the phosphor at 254 nm excitation.
In order to produce the phosphor of the present invention, a strong reducing atmosphere tends to be required, and activated carbon or the like is added rather than reduction using only hydrogen-containing nitrogen gas (nitrogen: hydrogen = 96: 4 (volume ratio)). It can be seen that stronger reduction is preferable.

[Comparative Example 2]
Heating was performed under the same conditions as in Example 9 except that no granular activated carbon was allowed to coexist. The obtained fired product was pulverized in an alumina mortar to obtain a phosphor.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
The phosphor of Comparative Example 2 also hardly emitted light when excited with blue light. It has been found that it is useful to coexist solid carbon when the phosphor of the present invention is heated.

[Comparative Example 3]
SrCO ₃ , Y ₂ O ₃ , and Eu ₂ O ₃ were weighed and mixed so that Sr: Y: Eu = 1: 2: 0.01 (molar ratio). The obtained raw material mixture was heated under the same conditions as in Example 1 (in the presence of granular activated carbon). The obtained fired product was pulverized in an alumina mortar to obtain a phosphor.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
The obtained material was SrY ₂ O ₄ containing Eu, but the emission with blue excitation was very weak. On the other hand, ultraviolet rays with a short wavelength such as 254 nm showed light emission derived from Eu ^{3+ although} it was very weak.
FIG. 8 shows an emission spectrum of the phosphor excited at 254 nm.
From this result, it is considered that Sc or Lu is indispensable for efficiently emitting light by blue excitation.

[Comparative Example 4]
A phosphor was manufactured under the same conditions as in Comparative Example 3 except that SrF ₂ was used as the flux.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
SrY ₂ O ₄ : Eu was obtained, but red light emission due to blue excitation derived from Eu ²⁺ was extremely weak. The valence of Eu in SrY ₂ O ₄ : Eu is mostly trivalent, and it is considered that the reduction to divalent is insufficient.

[Comparative Examples 5-6]
A phosphor was produced in the same manner as in Example 1 except that the raw material mixing ratio shown in Table 3 was used. In these comparative examples, phosphors having different types of constituent metal elements were manufactured without changing the composition ratio of the metal elements in Example 1.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
CaSc ₂ O ₄ : Eu (Comparative Example 5) and BaSc ₂ O ₄ : Eu (Comparative Example 6) were obtained, but neither emitted light due to blue excitation.
These results as M ¹ element in the formula [I], it can be seen that Sr is essential.

[Comparative Examples 7 to 9]
A phosphor was produced in the same manner as in Example 13 except that the raw material mixing ratio shown in Table 3 was used. In these comparative examples, phosphors having different types of constituent metal elements were manufactured without changing the composition ratio of the metal elements in Example 1.
Table 3 summarizes the emission characteristics of the obtained phosphor together with the phosphor raw material preparation composition.
BaSc ₂ O ₄ : Eu, BaYGdO ₄ : Eu, BaGd ₂ O ₄ : Eu were obtained, but none of them emitted light due to blue excitation. From the shape of the emission spectrum (not shown), it is presumed that the reduction of Eu to divalent is insufficient.
From these results, the M ¹ element in the formula [I], it can be seen that Sr is essential.

[Examples 37 to 54]
As the first phosphor, the red phosphor, Sr ₂ (Sc _1.4 Lu _0.6 ) O ₄ : Eu ²⁺ obtained in Example 20 (hereinafter sometimes referred to as the red phosphor 20). Y ₃ Al ₅ O ₁₂ : Ce (hereinafter sometimes referred to as phosphor [A]), CaSc ₂ O ₄ : Ce ³⁺ (hereinafter referred to as fluorescence) as the yellow or green phosphor that is the second phosphor. (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ (hereinafter sometimes referred to as phosphor [C]), Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce ³⁺ (hereinafter sometimes referred to as phosphor [D]) was used to produce a white light emitting device by the following procedure.
The phosphors [A] to [D] were synthesized with reference to the following documents.
Phosphor [A] JP 2005-150691 A, JP 2006-265542 A
Phosphor [B] JP 2006-45526 A, WO 2006-008935 A1
Phosphor [C] JP2007-023129A
Phosphor [D] JP 2006-137946 A, WO 2006-041168 A1

Hereinafter, in the description of the present embodiment, the reference numerals of the parts corresponding to FIG.
A blue LED [3] (C460MB manufactured by Cree) that emits light at a wavelength of around 460 nm was used as the first light emitter. This blue LED [3] was die-bonded to the terminal at the bottom of the recess [2A] of the frame [2] using silver paste as an adhesive. Next, using a gold wire with a diameter of 25 μm as the wire [6], the blue LED [3] and the electrode of the frame [2] were connected.

A phosphor mixture composed of two types of phosphors shown in Table 4 (red phosphor 20 and green or yellow phosphor) and a silicone resin (SCR 1011 manufactured by Shin-Etsu Chemical) are mixed well, and this phosphor-silicone resin mixture ( The phosphor-containing composition) was injected into the recess [2A] of the frame [2] to obtain a surface mount type light emitting device.
The ratios of the phosphors of the respective colors and the silicone resins in the respective examples are various ratios so that the CIE chromaticity coordinate values are x = 0.31 and y = 0.31, centering on the following ratios. It was adjusted with.
Red phosphor 20: 1.5 parts by weight Green or yellow phosphor: 5 parts by weight Silicone resin: 100 parts by weight

  When the obtained surface-mounted light-emitting device was driven by applying a current of 20 mA to the blue LED to emit light, white light was obtained in any of the light-emitting devices of the examples.

Measure the emission spectrum of the surface-mounted white light-emitting device in a room maintained at an air temperature of 25 ± 1 ° C using Ocean Optics color / illuminance measurement software and USB2000 series spectroscope (integral sphere specification) did.
Table 4 shows values of various emission characteristics (total luminous flux, light output, chromaticity coordinates, average color rendering index, color temperature, color deviation) calculated from the obtained emission spectrum.
In addition, the emission spectrum of the white light-emitting device obtained in Example 41, 45, 50, 54 is shown in FIGS. 9-12, respectively.

  Thus, by using the phosphor of the present invention in combination with an arbitrary yellow phosphor or green phosphor, a light emitting device and a light source for an image display device having a wide color reproduction range could be obtained.

It is typical sectional drawing which shows embodiment of the light-emitting device of this invention. It is typical sectional drawing which shows an example of the surface emitting illumination apparatus using the light-emitting device of this invention. (A) is a chart showing a powder X-ray diffraction (XRD) pattern of the phosphor obtained in Example 1, and (b) is a PDF No. Is a chart showing a standard pattern of SRSC ₂ O ₄ of 20-1213. It is a chart which shows the emission spectrum and excitation spectrum of the fluorescent substance obtained in Example 1 and Example 3. It is a SEM photograph of the fluorescent substance obtained in Examples 9-16. It is a chart which shows the emission spectrum of the fluorescent substance obtained in Example 17, 20 and 23. 6 is a chart showing an emission spectrum of the phosphor obtained in Comparative Example 1. 6 is a chart showing an emission spectrum of a phosphor obtained in Comparative Example 3. 42 is a chart showing an emission spectrum of a white light emitting device produced in Example 41. 42 is a chart showing an emission spectrum of a white light emitting device produced in Example 45. 6 is a chart showing an emission spectrum of a white light emitting device manufactured in Example 50. FIG. 42 is a chart showing an emission spectrum of a white light emitting device produced in Example 54.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Frame 2A The recessed part of a frame 3 Blue LED (1st light-emitting body)
4 Phosphor-containing part 5 Silver paste 6 Wire 11 Surface emitting illumination device 12 Holding case 13 Light emitting device 14 Diffusion plate

Claims (19)

A phosphor having a chemical composition represented by the following formula [1].
M ¹ _1-x Eu _x M ² _y O _z [1]
(In the above formula [1],
M ¹ represents a divalent metal element in which M ¹ is essential for Sr.
M ² represents a trivalent metal element essentially containing Sc or Lu.
x, y, and z are each
0.0001 ≦ x ≦ 0.1
1.8 ≦ y ≦ 2.2
3.6 ≦ z ≦ 4.4
Represents a number that satisfies )   The phosphor according to claim 1, wherein Eu in the formula [1] is divalent Eu. In the formula [1],
The content of Sr in M ¹ is at least 40 mol% of the total ^{M 1,}
The phosphor according to claim 1 or claim 2 total content of Sc and Lu is equal to or less than 50 mole% of the total M ² in M ^2. In the formula [1],
M ¹ is one or two metal elements selected from the group consisting of Ca and Ba, and Sr only or Sr is essential.
M ² is a metal element composed solely of Sc and / or Lu, or Sc or Lu as an essential element, and one or more selected from the group consisting of Sc, Al, Y, Lu, Gd, and La The phosphor according to any one of claims 1 to 3, wherein the phosphor is a metal element.   The phosphor according to any one of claims 1 to 4, wherein the phosphor has an emission peak in a wavelength range of 610 nm to 750 nm.   The phosphor according to any one of claims 1 to 5, wherein the half-value width of the emission peak is 70 nm or more and 120 nm or less. In the formula [1], as M ^2, phosphor according to any one of claims 1, characterized in that it comprises a Sc and Lu 6. A phosphor characterized by satisfying the following conditions (1) to (4).
(1) Oxide phosphor showing red emission based on Eu ²⁺ emission
(2) Excited by light in the wavelength range from 420 nm to 550 nm
(3) The emission peak has a wavelength in the range of 610 nm to 750 nm, and the half width of the emission peak is 70 nm or more.
(4) The internal quantum efficiency in excitation with light having a wavelength of 455 nm at room temperature is 5% or more.   The phosphor according to claim 8, comprising Sr.   The phosphor according to claim 8 or 9, comprising Sc.   The phosphor according to any one of claims 8 to 10, comprising Lu.   A method for producing a phosphor according to any one of claims 1 to 11, comprising a step of firing the phosphor material in a strong reducing atmosphere.   A phosphor-containing composition comprising the phosphor according to any one of claims 1 to 11 and a liquid medium. A first light emitter, and a second light emitter that emits visible light by irradiation of light from the first light emitter,
12. The light emitting device, wherein the second light emitter contains one or more of the phosphors according to any one of claims 1 to 11 as a first phosphor.   The light emitting device according to claim 14, wherein the second phosphor includes at least one phosphor having an emission peak wavelength different from that of the first phosphor as the second phosphor. The first light emitter has a light emission peak in a wavelength range of 420 nm to 500 nm;
16. The light emitting device according to claim 15, wherein the second luminous body contains at least one kind of phosphor having an emission peak in a wavelength range of 500 nm to 610 nm as the second phosphor. . The first light emitter has a light emission peak in a wavelength range of 300 nm or more and 420 nm or less;
The second phosphor, as the second phosphor, has at least one phosphor having an emission peak in a wavelength range of 420 nm to 500 nm and at least one having an emission peak in a wavelength range of 500 nm to 610 nm. The light-emitting device according to claim 15, further comprising a seed phosphor.   An image display device comprising the light-emitting device according to claim 14 as a light source.   An illumination device comprising the light-emitting device according to claim 14 as a light source.

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