JP2012207228A - Phosphor and light-emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high-luminance complex nitride or an oxynitride phosphor.SOLUTION: In the phosphor having a nitride or an oxynitride as a base, the supernatant liquid obtained by dispersing the phosphor in water, wherein the weight ratio of the water to the phosphor is 1:10, and then leaving the resulting dispersion to stand for one hour has electrical conductivity of not more than 50 mS/m. In the light-emitting device having an excitation light source and a phosphor which makes the wavelength conversion of at least part of the light from the excitation light source, this phosphor is used as the phosphor.

Description

  The present invention relates to a high-luminance phosphor based on nitride or oxynitride. The present invention also relates to 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.

  Phosphors are used in fluorescent lamps, fluorescent display tubes (VFD), field emission displays (FED), plasma display panels (PDP), cathode ray tubes (CRT), white light emitting diodes (LEDs) and the like. In any of these applications, in order to make the phosphor emit light, it is necessary to supply the phosphor with energy for exciting the phosphor, and the phosphor is not limited to vacuum ultraviolet rays, ultraviolet rays, visible rays, electron beams, etc. When excited by an excitation source having high energy, it emits ultraviolet rays, visible rays, and infrared rays. However, when the phosphor is exposed to the excitation source as described above for a long time, there is a problem that the luminance of the phosphor decreases.

  Therefore, in recent years, ternary systems have been used in place of conventional phosphors such as silicate phosphors, phosphate phosphors, aluminate phosphors, borate phosphors, sulfide phosphors, and oxysulfide phosphors. Many new materials have been synthesized for the above nitrides. Particularly recently, phosphors having excellent characteristics in multi-component nitrides and oxynitrides based on silicon nitride have been developed.

In Patent Document 1, the general formula M _x Si _y N _z : Eu [where M is at least one alkaline earth metal element selected from the group consisting of Ca, Sr, and Ba, and z = 2 / 3x + 4. / 3y] is disclosed. These phosphors are synthesized by nitriding an alkaline earth metal metal to synthesize an alkaline earth metal nitride and adding silicon nitride thereto, or using an alkaline earth metal and silicon imide as a raw material. It is synthesized by heating in ₂ or Ar airflow. In both cases, alkaline earth metal metals sensitive to air and moisture had to be used as raw materials, and there was a problem in industrial mass synthesis.

In addition, Patent Document 2 discloses an oxynitride having a structure M ₁₆ Si ₁₅ O ₆ N ₃₂ , a structure MSiAl ₂ O ₃ N ₂ , M ₁₃ Si ₁₈ Al ₁₂ O ₁₈ N ₃₆ , MSi ₅ Al ₂ ON _9, and M ₃ Si _5. An oxynitride phosphor derived from AlON ₁₀ sialon is disclosed. In particular, when M is Sr, SrCO ₃ and AlN and Si ₃ N ₄ are mixed at a ratio of 1: 2: 1, heated in a reducing atmosphere (N ₂ / H ₂ ), and SrSiAl ₂ O ₃ N ₂ : It is described that Eu ²⁺ was obtained.
In this case, the obtained phosphor is only oxynitride, and no nitride containing no oxygen is obtained.

  In addition, since the nitride or oxynitride phosphor has a low reactivity of the raw material powder used, it is compression molded at a high temperature for the purpose of promoting a solid phase reaction between the raw material mixed powders during firing. That is, in order to be heated by increasing the contact area between the raw material powders, it is synthesized in the state of a very hard sintered body. Therefore, the sintered body obtained in this way needs to be pulverized to a fine powder suitable for the intended use of the phosphor. However, when a phosphor made of a hard sintered body is pulverized over a long period of time and with a large amount of energy using a normal mechanical pulverization method such as a jaw crusher or a ball mill, many defects are present in the crystal matrix of the phosphor. Has been caused, and the emission intensity of the phosphor is significantly reduced.

  For this reason, a method of firing in a powder state without compression molding at the time of heating was attempted, but since the target phosphor is not generated at low temperature without promoting a solid phase reaction between the nitride powders of the raw material, It was necessary to synthesize the phosphor at a high temperature of 1800 ° C. or higher. However, when firing at such a high temperature, there arises a disadvantage that a decomposition reaction accompanied by desorption of nitrogen from the nitride raw material occurs, and thus firing is performed in a nitrogen gas atmosphere of 5 atm or more for the purpose of suppressing it. Therefore, not only high firing energy is required, but also a very expensive high-temperature and high-pressure firing furnace is required, which increases the manufacturing cost of the phosphor.

When a nitride having a low oxygen concentration is synthesized, an alkaline earth such as calcium nitride (Ca ₃ N ₂ ) or strontium nitride (Sr ₃ N ₂ ) is used instead of using an alkaline earth metal oxide raw material powder. Although it is necessary to use a metal nitride, in general, a divalent metal nitride is unstable in a moisture-containing atmosphere, and easily reacts with moisture to form a hydroxide, particularly in the case of Sr. The trend is remarkable. For this reason, it was difficult to keep the oxygen concentration contained in the synthesized phosphor low.

  For these reasons, a new manufacturing method that does not use these metal nitrides as raw materials has been demanded.

  In recent years, Patent Document 3 has been reported regarding a method for producing a nitride phosphor using a metal as a starting material. Patent Document 3 discloses an example of a method for producing an aluminum nitride phosphor, which describes that transition elements, rare earth elements, aluminum and alloys thereof can be used as raw materials. However, an example using an alloy as a raw material is not described, and it is characterized by using Al metal as an Al source. In addition, it differs from the present invention in that a combustion synthesis method is used to ignite the raw material and instantaneously raise the temperature to a high temperature (3000 K). That is, with the method of instantaneously raising the temperature to 3000 K, the activating elements cannot be uniformly distributed, and it is difficult to obtain a phosphor with high characteristics. Moreover, there is no description regarding a nitride phosphor containing an alkaline earth element obtained from an alloy raw material, and further a nitride phosphor containing silicon.

Special table 2003-515665 gazette JP 2003-206481 A JP 2005-54182 A

In a new method for producing a phosphor using an alloy as a raw material and a nitride or oxynitride as a base material, a technique capable of providing a phosphor with higher brightness is required.
An object of this invention is to provide the technique which improves the brightness | luminance of fluorescent substance by a simple method.

The inventors of the present invention have prepared phosphors based on nitrides or oxynitrides manufactured using alloys as raw materials, and pulverizing and classifying the phosphors as necessary, and water having a weight 10 times that of the phosphors. And found that there is a correlation between the electrical conductivity, which is an indicator of the amount of dissolved ions in the supernatant obtained by standing for 1 hour, and the luminous efficiency of the phosphor. I let you.
That is, the gist of the present invention is the following (1) to (7).

(1) A nitride phosphor represented by the following general formula [2], wherein 2θ is 35.5 ° to 37 ° in a powder X-ray diffraction pattern using Cu-Kα rays (1.54184 mm). When the intensity ratio of the peak height I _p of 2θ = 33.2 ° ± 0.2 ° to the height I _max of the strongest peak in the range is I = (I _p × 100) / I _max A nitride phosphor characterized by being 3 or less.
M ^{1 ′} _{a ′} Sr _{b ′} Ca _{c ′} Al _{e ′} Sif _′ N _{g ′} [2]
(However, a ′, b ′, c ′, e ′, f ′, and g ′ are values in the following ranges, respectively.
0.00001 ≦ a ′ ≦ 0.15
0.6 ≦ b ′ ≦ 0.99999
0 ≦ c ′ <1
a ′ + b ′ + c ′ = 1
0.8 ≦ e ′ ≦ 1.2
0.8 ≦ f ′ ≦ 1.2
2.5 ≦ g ′ ≦ 3.5
M ^{1 ′} represents Eu and / or Ce. )

(2) The nitride phosphor according to (1), wherein M ^{1 ′} is Eu.

(3) The nitride phosphor according to (1) or (2), wherein 0.7 ≦ b ′ ≦ 0.99999.

(4) The nitride phosphor according to any one of (1) to (3), which contains 5% by weight or less of oxygen.

(5) A phosphor-containing composition comprising the phosphor according to any one of (1) to (4) and a liquid medium.

(6) In a light emitting device having an excitation light source and a phosphor that converts the wavelength of at least part of light from the excitation light source, the phosphor is any one of (1) to (4). A light emitting device characterized by the above.

(7) An image display device comprising the light emitting device according to (6).

(8) A lighting device comprising the light emitting device according to (6).

According to the present invention, the brightness of the phosphor can be improved by a simple method.
In addition, by using a composition containing this phosphor, a light emitting device with high luminous efficiency can be obtained. This light emitting device is suitably used for applications such as an image display device and a lighting device.

It is typical sectional drawing which shows one Example 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. It is a typical perspective view which shows other embodiment of the light-emitting device of this invention. 6 is a chart showing an emission spectrum of a phosphor after washing in Example 3. 6 is a chart showing a powder X-ray diffraction pattern of the phosphor after cleaning in Example 3. FIG. 6 is a chart showing a powder X-ray diffraction pattern of an unwashed phosphor of Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Composition of phosphor]
Although there is no restriction | limiting in particular about the composition of the fluorescent substance which makes the nitride or oxynitride of this invention a base material, An example is given and demonstrated below.

Phosphor of the present invention is intended preferably include the activator elements M ^1, and tetravalent metal elements M ⁴ including at least Si, one or more and the metal elements other than Si, particularly, the The phosphor of the invention includes an activating element M ¹ , a divalent metal element M ² , and a tetravalent metal element M ⁴ containing at least Si. For _{example, Sr 2 Si 5 N 8:} Eu, Ce , and the like. Here, as a metal element other than Si, an alkaline earth metal element is preferable.

The phosphor of the present invention can also contain an activating element M ¹ , a divalent metal element M ² , a trivalent metal element M ³ , and a tetravalent metal element M ⁴ containing at least Si. It is preferable to use a nitride or oxynitride represented by the general formula [1] as a base.
_{^{M 1 a M 2 b M 3}} c M 4 d N e O f [1]
(However, a, b, c, d, e, and f are values in the following ranges, respectively.
0.00001 ≦ a ≦ 0.15
a + b = 1
0.5 ≦ c ≦ 1.5
0.5 ≦ d ≦ 1.5
2.5 ≦ e ≦ 3.5
0 ≦ f ≦ 0.5)

As the activator element M ¹ , various light-emitting ions that can be contained in a crystal matrix constituting a phosphor having a nitride or oxynitride as a matrix can be used, but Cr, Mn, Fe, Ce, Pr It is preferable to use one or more elements selected from the group consisting of Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb because a phosphor with high emission characteristics can be produced. The activator element M ¹ preferably contains one or more of Mn, Ce, Pr and Eu, and particularly contains Ce and / or Eu to obtain a phosphor exhibiting high-luminance red light emission. More preferably. Moreover, in order to give various functions, such as raising a brightness | luminance and providing luminous property, as activator element M1, ¹ or more types of coactivators may be contained in addition to Ce and / or Eu. good.

The elements other than the activating element ^{M 1,} divalent various trivalent, but tetravalent metal elements may be used, the divalent metal elements ^{M 2} is Mg, Ca, Sr, Ba, and from Zn one or more elements selected from the group consisting of trivalent metal elements ^{M 3} is Al, Ga, in, and at least one element selected from the group consisting of Sc, 4-valent metal elements ^{M 4} is Si, Ge , Sn, Ti, Zr and Hf are preferably one or more elements selected from the group consisting of Hf, because a phosphor with high emission characteristics can be obtained.

Also preferred since divalent and 50 mol% or more of the metal elements M ² to adjust the composition so that the Ca and / or Sr emission characteristics of high phosphor obtained, more than 80 mole% of M ² Ca And / or Sr, more preferably 90 mol% or more is Ca and / or Sr, and most preferably all M ² is Ca and / or Sr.

Further, it is preferable to adjust the composition so that 50 mol% or more of the trivalent metal element M ³ is Al, because a phosphor having high emission characteristics can be obtained. However, 80 mol% or more of M ³ is preferably Al. Preferably, 90 mol% or more is more preferably Al, and most preferably all M ³ is Al.

Further, it is preferable to adjust the composition so that at least 50 mol% of the tetravalent metal element M ⁴ containing Si becomes Si, so that a phosphor with high emission characteristics can be obtained. However, 80 mol% or more of M ⁴ is preferably Si mol. More preferably, 90 mol% or more is Si, and all M ⁴ is preferably Si.

In particular, 50 mol% or more of M ² is Ca and / or Sr, 50 mol% or more of M ³ is Al, and 50 mol% or more of M ⁴ is Si. It is preferable because a phosphor having particularly high emission characteristics can be produced.

  In addition, the reason why the numerical range of a to f in the general formula [1] is preferable is as follows.

  When a is smaller than 0.00001, sufficient light emission intensity tends to be not obtained, and when a is larger than 0.15, concentration quenching increases and the light emission intensity tends to decrease. Accordingly, the raw materials are mixed so that a is in the range of 0.00001 ≦ a ≦ 0.15. For the same reason, 0.0001 ≦ a ≦ 0.1 is preferable, 0.001 ≦ a ≦ 0.05 is more preferable, 0.002 ≦ a ≦ 0.04 is further preferable, and 0.004 ≦ a ≦ 0. .02 is most preferred.

Since the activator M ¹ replaces the atomic position of the metal element M ^{2 in} the phosphor crystal matrix, the total of a and b is adjusted so that the raw material mixture composition is 1.

  When c is smaller than 0.5 or when c is larger than 1.5, a heterogeneous phase is produced during production, and the yield of the phosphor tends to be low. Therefore, the raw materials are mixed so that c is in the range of 0.5 ≦ c ≦ 1.5. From the viewpoint of emission intensity, 0.5 ≦ c ≦ 1.5 is preferable, 0.6 ≦ c ≦ 1.4 is more preferable, and 0.8 ≦ c ≦ 1.2 is most preferable.

  Whether d is smaller than 0.5 or d is larger than 1.5, a heterogeneous phase is produced during production, and the yield of the phosphor tends to be low. Accordingly, the raw materials are mixed so that d is in the range of 0.5 ≦ d ≦ 1.5. From the viewpoint of light emission intensity, 0.5 ≦ d ≦ 1.5 is preferable, 0.6 ≦ d ≦ 1.4 is more preferable, and 0.8 ≦ d ≦ 1.2 is most preferable.

となる。この式に０．５≦ｃ≦１．５，０．５≦ｄ≦１．５を代入すれば、ｅの範囲は
１．８４≦ｅ≦４．１７
となる。しかしながら、前記一般式［１］で表される蛍光体組成において、窒素の含有量を示すｅが２．５未満であると蛍光体の収率が低下する傾向にある。また、ｅが３．５を超えても蛍光体の収率が低下する傾向にある。従って、ｅは通常２．５≦ｅ≦３．５である。 e is a coefficient indicating the nitrogen content;

It becomes. If 0.5 ≦ c ≦ 1.5 and 0.5 ≦ d ≦ 1.5 are substituted into this equation, the range of e is 1.84 ≦ e ≦ 4.17.
It becomes. However, in the phosphor composition represented by the general formula [1], the yield of the phosphor tends to decrease when e indicating the nitrogen content is less than 2.5. Even if e exceeds 3.5, the yield of the phosphor tends to decrease. Therefore, e is usually 2.5 ≦ e ≦ 3.5.

  The oxygen in the phosphor represented by the general formula [1] may be mixed as an impurity in the raw metal, or may be introduced during a manufacturing process such as a pulverization process or a nitriding process. The ratio of oxygen f is preferably in the range of 0 ≦ f ≦ 0.5 within a range in which a decrease in the light emission characteristics of the phosphor is acceptable.

Among the phosphors represented by the general formula [1], the phosphor represented by the following general formula [2] can be used.
M ^{1 ′} _{a ′} Sr _{b ′} Ca _{c ′} M ^{2 ′} _{d ′} Al _{e ′} Sif _′ N _{g ′} [2]
(However, a ′, b ′, c ′, d ′, e ′, f ′, and g ′ are values in the following ranges, respectively.
0.00001 ≦ a ′ ≦ 0.15
0.1 ≦ b ′ ≦ 0.99999
0 ≦ c ′ <1
0 ≦ d ′ <1
a ′ + b ′ + c ′ + d ′ = 1
0.5 ≦ e ′ ≦ 1.5
0.5 ≦ f ′ ≦ 1.5
0.8 × (2/3 + e ′ + 4/3 × f ′) ≦ g ′ ≦ 1.2 × (2/3 + e ′ + 4/3 × f ′))

Here, M ^{1 ′} is the group consisting of Cr, Mn, Fe, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb, similarly to M ¹ in the general formula [1]. Represents an activation element selected from Among them, the activator element M ^{1 ′} preferably includes one or more of Mn, Ce, Pr, and Eu, and particularly preferably includes Eu and / or Ce.

M ^{2 ′} represents Mg and / or Ba, and is preferably Mg. By containing Mg, the emission wavelength of the phosphor can be made long wave.

  The range of a ′ is usually 0.00001 ≦ a ′ ≦ 0.15, preferably 0.001 ≦ a ′ ≦ 0.05, more preferably 0.002 ≦ a ′ ≦ 0.01.

  The range of b ′ is usually 0.1 ≦ b ′ ≦ 0.99999, preferably 0.6 ≦ b ′ ≦ 0.99999, and more preferably 0.7 ≦ b ′ ≦ 0.99999.

  The range of c ′ is usually 0 ≦ c ′ <1, preferably 0 ≦ c ′ ≦ 0.5, and more preferably 0 ≦ c ′ ≦ 0.3.

  The range of d is usually 0 ≦ d ′ <1, preferably 0 ≦ d ′ ≦ 0.5, and more preferably 0 ≦ d ′ ≦ 0.2.

The relationship between a ′, b ′, c ′, d ′ is usually
a ′ + b ′ + c ′ + d ′ = 1
Satisfied.

  The range of e ′ is usually 0.5 ≦ e ′ ≦ 1.5, preferably 0.8 ≦ e ′ ≦ 1.2, and more preferably 0.9 ≦ e ′ ≦ 1.1.

  The range of f ′ is usually 0.5 ≦ f ′ ≦ 1.5, preferably 0.8 ≦ f ′ ≦ 1.2, and more preferably 0.9 ≦ f ′ ≦ 1.1.

The range of g ′ is usually 0.8 (2/3 + e ′ + 4/3 × f ′) ≦ g ′ ≦ 1.2 × (2/3 + e ′ + 4/3 × f ′), preferably 0.9. × (2/3 + e ′ + 4/3 × f ′) ≦ g ′ ≦ 1.1 × (2/3 + e ′ + 4/3 × f ′), more preferably 2.5 ≦ g ′ ≦ 3.5. .

  Hereinafter, a phosphor in which the value of b ′ in the general formula [2] is in the range of 0.6 ≦ b ′ ≦ 0.99999 and d ′ = 0, that is, a phosphor having a large amount of Sr substitution. Is abbreviated as “SCASN phosphor”.

Oxygen contained in the phosphor of the present invention may be mixed as an impurity in the raw metal, or mixed during a manufacturing process such as a pulverization process or a nitriding process.
The oxygen content is usually 5% by weight or less, preferably 2% by weight or less, and most preferably 1% by weight or less as long as the reduction in the light emission characteristics of the phosphor is acceptable. There is a tendency that the oxygen content of the phosphor is decreased by the cleaning described later.
Specific examples of the composition of the phosphor include (Sr, Ca, Mg) AlSiN ₃ : Eu, (Sr, Ca, Mg) AlSiN ₃ : Ce, (Sr, Ca) ₂ Si ₅ N ₈ : Eu, (Sr, Ca, Mg) _{Ca) 2 Si 5 N 8:} Ce , and the like.

[Phosphor production method]
In order to produce the phosphor of the present invention, for example, a metal as a raw material or an alloy thereof is weighed so as to have the composition of the following general formula [3], and melted to be alloyed to obtain an alloy for phosphor raw material. Next, the phosphor raw material alloy is pulverized, nitrided, and washed. In that case, for example, when manufacturing an alloy containing Si and an alkaline earth metal element, after melting a high melting point (high boiling point) Si metal and / or an alloy containing Si, a low melting point (low boiling point) It is preferable to melt the alkaline earth metal.
M ¹ _a M ² _b M ³ _c M ⁴ _d [3]
(However, M ¹ , M ² , M ³ , M ⁴ , a, b, c, and d are respectively synonymous with those in the general formula [1].)

<Purity of raw metal>
The purity of the metal used for the production of the alloy is 0.1 mol% or less, preferably 0.01 mol% or less, as the metal raw material of the activation element M ¹ from the viewpoint of the light emission characteristics of the phosphor to be synthesized. It is preferable to use a metal that has been purified to a minimum. When using Eu as activator elements M ^1, it is preferable to use Eu metal as Eu raw material. As the raw material of the activator elements M ¹ other elements, divalent, trivalent, but using a tetravalent various metals such as, for the same reason, the impurity concentration of both of which are contained in 0.1 mol% or less Preferably, it is preferable to use a high-purity metal raw material of 0.01 mol% or less from the viewpoint that a phosphor with high emission characteristics can be produced.

<Raw metal shape>
Although there is no restriction | limiting in the shape of a raw material metal, Usually, the thing of a granular form or a lump shape with a diameter of several mm to several dozen mm is used.
When using the divalent alkaline earth metal as the metallic element M ^2, as a raw material thereof, granular, but shapes such as bulk is not limited, it is preferable to select an appropriate shape depending on the chemical nature of the material. For example, Ca is stable in the atmosphere in either a granular form or a lump, and can be used. However, since Sr is chemically more active, it is preferable to use a lump raw material.

<Melting of raw metal>
In the melting of the raw material metal, there is the following problem particularly when an alloy for a phosphor raw material containing an alkaline earth metal element as Si and the divalent metal element M ² is produced.

  The melting point of Si is 1410 ° C., which is about the same as the boiling point of alkaline earth metals (for example, Ca has a boiling point of 1494 ° C., Sr has a boiling point of 1350 ° C., and Ba has a boiling point of 1537 ° C.). In particular, since the boiling point of Sr is lower than the melting point of Si, it is extremely difficult to simultaneously melt Sr and Si.

Therefore, in the present invention, this problem has been solved by melting the Si metal first, preferably producing a master alloy, and then melting the alkaline earth metal.
Furthermore, by melting the alkaline earth metal after melting the Si metal in this way, the purity of the obtained alloy is improved, and the effect of significantly improving the properties of the phosphor using it as a raw material is also exhibited.

Although there is no restriction | limiting in particular about the melting method of the raw material metal in this invention, Usually, an arc melting method, a high frequency melting method, etc. can be used.
Hereinafter, the case of (1) arc melting / electron beam melting and (2) high frequency melting will be described in more detail as an example.

(1) In the case of arc melting and electron beam melting In the case of arc melting and electron beam melting, melting is performed according to the following procedure.
i) melting Si metal or an alloy containing Si by electron beam or arc discharge;
ii) Next, the alkaline earth metal is melted by indirect heating to obtain an alloy containing Si and the alkaline earth metal.
Here, after the alkaline earth metal is dissolved in the molten metal containing Si, mixing may be promoted by heating and stirring with an electron beam or arc discharge.

(2) In the case of high-frequency melting Since an alloy containing alkaline earth has high reactivity with oxygen, it must be melted in a vacuum or an inert gas, not in the atmosphere. Under such conditions, high frequency melting is usually preferred. However, Si is a semiconductor and is difficult to melt by induction heating using high frequency. For example, the resistivity of aluminum at 20 ° C. is 2.8 × 10 ⁻⁸ Ω · m, while the resistivity of polycrystalline Si for semiconductor is 10 ⁵ Ω · m or more. Since a material having such a large specific resistance cannot be directly melted at high frequency, generally, a conductive susceptor is used, and heat is transferred by heat conduction or radiation to melt. The susceptor may be disc-shaped or tubular, but a crucible is preferably used. As the material of the susceptor, graphite, molybdenum, silicon carbide and the like are generally used, but these have a problem that they easily react with an alkali metal. On the other hand, crucibles (alumina, calcia, etc.) capable of melting alkaline earth metals are insulators and cannot be used as susceptors. Therefore, when alkaline earth metal and silicon are charged into a crucible and melted at high frequency, Si metal and alkaline earth metal are simultaneously melted by indirect heating using a known conductive crucible (such as graphite) as a susceptor. It is impossible to do. Therefore, this problem is solved by melting in the following order.
i) The Si metal is melted by indirect heating using a conductive crucible.
ii) Next, an alloy containing Si and alkaline earth is obtained by melting the alkaline earth metal using an insulating crucible.

  The Si metal may be cooled between the steps i) and ii), or the alkaline earth metal may be continuously melted without being cooled. When performing continuously, a crucible coated with calcia, alumina or the like suitable for melting an alkaline earth metal in a conductive container can be used.

More specific steps are described as follows.
i) In high frequency melting, Si metal and metal M (for example, Al, Ga) are melted by indirect heating using a conductive crucible to obtain a conductive alloy (mother alloy).
ii) Next, an alkaline earth metal resistant crucible is used to melt the mother alloy of i), and then the alkaline earth metal is melted to obtain an alloy containing Si and the alkaline earth metal.

  As a specific method for melting the Si metal or the Si-containing master alloy first and then melting the alkaline earth metal, for example, the Si metal or Si-containing master alloy is first melted, and then the alkaline earth metal is melted there. And the like.

Si can be alloyed with a metal M other than the divalent metal element M ² to impart conductivity. In this case, the melting point of the obtained alloy is preferably lower than that of Si. An alloy of Si and Al is particularly preferable because the melting point is around 1010 ° C. and the melting point is lower than the boiling point of the alkaline earth metal.
When a mother alloy of Si and a metal M other than the divalent metal element M ² is used, the composition is not particularly limited, but the mother alloy preferably has conductivity, and is usually in molar ratio. In the range of Si: M = 1: 0.01-5, it is preferable to manufacture a mother alloy having a melting point lower than the boiling point of the alkaline earth metal.
In addition, Si metal can also be added to the master alloy containing Si.

In the present invention, other than melting the alkaline earth metal after melting the Si metal, there is no particular limitation on the melting time of the other raw metal, but usually a large amount or a high melting point Thaw first.
In order to disperse the activation element M ¹ uniformly, and since the addition amount of the activation element M ¹ is small, it is preferable to melt the activation element M ¹ after melting the Si metal.

In the case of producing a phosphor raw material alloy represented by the above general formula [3], in which the tetravalent metal element M ⁴ is Si and at least Sr is contained as the divalent metal element M ² , the following procedure is performed. It is preferable to melt with.
(1) preparing a mother alloy of Si and trivalent metal elements M ^3. At this time, preferably Si and M ³ are alloyed at a Si: M ³ ratio in the general formula [3].
(2) After melting the master alloy of (1), melt Sr.
(3) Thereafter, the divalent metal elements other than Sr, to melt the activator elements M ^1.

  The atmosphere at the time of melting such a raw material metal is preferably an inert atmosphere, and Ar is particularly preferable.

Further, the pressure is usually preferably 1 × 10 ³ Pa or more and 1 × 10 ⁵ Pa or less, and it is desirable that the pressure is not more than atmospheric pressure from the viewpoint of safety.

<Casting of molten metal>
There are many technical problems in producing a phosphor directly from a molten alloy produced by melting a raw metal. Therefore, a solidified body is obtained through a casting process in which molten alloy produced by melting the raw metal is poured into a mold and molded. However, in this casting process, segregation occurs due to the cooling rate of the molten metal, and a composition that has a uniform composition in the molten state may have an uneven composition distribution. Therefore, it is desirable that the cooling rate be as fast as possible. The mold is preferably made of a material having good thermal conductivity such as copper, and preferably has a shape in which heat is easily dissipated. It is also preferable to devise cooling the mold by means such as water cooling if necessary.

  By such a device, for example, it is preferable to use a mold having a large bottom area with respect to the thickness and solidify as soon as possible after pouring the molten metal into the mold.

  Also, since the degree of segregation varies depending on the composition of the alloy, it is necessary to prevent segregation by collecting samples from several places of the obtained solidified body by using necessary analytical means such as ICP emission spectroscopy. It is preferable to set a proper cooling rate.

  The casting atmosphere is preferably an inert atmosphere, and Ar is particularly preferable.

<Ingot crushing>
The alloy lump obtained in the casting process is then pulverized to prepare an alloy powder having a desired particle size and particle size distribution. As the pulverization method, a dry method or a wet method using an organic solvent such as ethylene glycol, hexane, or acetone can be used. Hereinafter, the dry method will be described in detail as an example.
This pulverization step may be divided into a plurality of steps such as a coarse pulverization step, a medium pulverization step, and a fine pulverization step as necessary. In this case, the entire pulverization process can be pulverized using the same apparatus, but the apparatus used may be changed depending on the process.

  The coarse pulverization step is a step of pulverizing to a diameter of about 1 cm, and a pulverizing apparatus such as a jaw crusher, a gyre crusher, a crushing roll, or an impact crusher can be used. The medium pulverization step is a step of pulverizing to a diameter of about 1 mm, and a pulverizer such as a cone crusher, a crushing roll, a hammer mill, or a disk mill can be used. In the fine pulverization step, a pulverizer such as a ball mill, a tube mill, a rod mill, a roller mill, a stamp mill, an edge runner, a vibration mill, and a jet mill can be used.

  Among these, from the viewpoint of preventing contamination of impurities, it is preferable to use a jet mill in the pulverization step. In order to use a jet mill, the alloy lump needs to be pulverized in advance to a particle size of about several mm (for example, 50 μm to 5 mm). In the jet mill, the particles are pulverized mainly by using the expansion energy of the fluid injected from the nozzle original pressure to the atmospheric pressure. Therefore, the particle size can be controlled by the pulverization pressure, and contamination of impurities can be prevented. Is possible. Although the pulverization pressure varies depending on the apparatus, it is usually in the range of 0.01 MPa or more and 2 MPa or less in gauge pressure. Among them, 0.05 MPa or more and less than 0.4 MPa is preferable, and 0.1 MPa or more and 0.3 MPa or less. Is more preferable.

In any case, it is necessary to appropriately select the relationship between the material of the pulverizer and the object to be crushed so that impurities such as iron do not enter during the pulverization process. For example, the contact portion is preferably provided with a ceramic lining, and among ceramics, alumina, tungsten carbide, zirconia and the like are preferable.
In order to prevent oxidation of the alloy powder, the pulverization is preferably performed in an inert gas atmosphere, and the oxygen concentration in the inert gas atmosphere is preferably 10% or less, particularly preferably 5% or less. Moreover, as a minimum of oxygen concentration, it is about 10 ppm normally. By setting the oxygen concentration within a specific range, it is considered that an oxide film is formed on the surface of the alloy during pulverization and stabilized. When the pulverization step is performed in an atmosphere having an oxygen concentration higher than 5%, dust may be exothermic and combusted during the pulverization. Therefore, equipment that does not generate dust is necessary. Although there is no restriction | limiting in particular in the kind of inert gas, Usually, 1 type single atmosphere or 2 or more types mixed atmosphere is used among gases, such as nitrogen, argon, and helium, and nitrogen is especially preferable from a viewpoint of economical efficiency.

<Classification of alloy powder>
The alloy powder pulverized in the pulverization process is divided into a desired weight median by using a sieving device using a mesh such as a vibrating screen and a shifter, an inertia classifier such as an air separator, and a centrifuge such as a cyclone. It is adjusted to the diameter _{D 50} and particle size distribution.

  This classification step is also preferably performed in an inert gas atmosphere, and the oxygen concentration in the inert gas atmosphere is preferably 10% or less, particularly preferably 5% or less. Although there is no restriction | limiting in particular in the kind of inert gas, Usually, 1 type (s) or 2 or more types, such as nitrogen, argon, helium, are used, and nitrogen is especially preferable from a viewpoint of economical efficiency.

<Nitriding of alloys>
For example, the nitriding treatment of the phosphor raw material alloy is performed as follows.
That is, first, an alloy powder as a nitriding raw material is filled in a crucible or a tray. Examples of the material of the crucible or tray used here include boron nitride, silicon nitride, aluminum nitride, and tungsten. Boron nitride is preferable because of its excellent corrosion resistance.

  After putting the crucible or tray filled with the alloy powder into a heating furnace capable of controlling the atmosphere, a gas containing nitrogen is circulated to sufficiently replace the inside of the system with the nitrogen-containing gas. If necessary, a nitrogen-containing gas may be circulated after the system is evacuated.

  Examples of the nitrogen-containing gas used in the nitriding treatment include a gas containing nitrogen, such as nitrogen, ammonia, or a mixed gas of nitrogen and hydrogen. The oxygen concentration in the system affects the oxygen content of the phosphor to be produced, and if the content is too high, high light emission cannot be obtained. Therefore, the oxygen concentration in the nitriding atmosphere is preferably as low as possible, usually 1000 ppm or less, Preferably it is 100 ppm or less, More preferably, it is 10 ppm or less. Further, if necessary, an oxygen getter such as carbon or molybdenum may be placed in the in-system heating portion to lower the oxygen concentration.

  The nitriding treatment is performed by heating in a state filled with or containing a nitrogen-containing gas, but the pressure may be any of a reduced pressure, an atmospheric pressure or a pressurized pressure rather than atmospheric pressure. In order to prevent oxygen from being mixed in the atmosphere, the pressure is preferably set to atmospheric pressure or higher. If the pressure is less than atmospheric pressure, if the heating furnace has poor sealing properties, a large amount of oxygen may be mixed and a phosphor having high characteristics may not be obtained. The pressure of the nitrogen-containing gas is preferably at least 0.2 MPa as a gauge pressure, and most preferably from 10 MPa to 200 MPa.

  The heating of the alloy powder is usually performed at a temperature of 800 ° C. or higher, preferably 1000 ° C. or higher, more preferably 1200 ° C. or higher, and usually 2200 ° C. or lower, preferably 2100 ° C. or lower, more preferably 2000 ° C. or lower. When the heating temperature is lower than 800 ° C., the time required for the nitriding treatment becomes very long, which is not preferable. On the other hand, when the heating temperature is higher than 2200 ° C., the generated nitride is volatilized or decomposed, the chemical composition of the obtained nitride phosphor shifts, and a phosphor with high characteristics cannot be obtained, and the reproducibility is also poor. There is a risk of becoming something.

  The heating time (holding time at the maximum temperature) during the nitriding treatment may be a time required for the reaction between the alloy powder and nitrogen, but is usually 1 minute or more, preferably 10 minutes or more, more preferably 30 minutes or more, Preferably it is 60 minutes or more. When the heating time is shorter than 1 minute, the nitriding reaction is not completed and a phosphor having high characteristics cannot be obtained. The upper limit of the heating time is determined from the viewpoint of production efficiency, and is usually 24 hours or less.

<Washing>
The phosphor obtained by nitriding the phosphor raw material alloy is roughly pulverized with a jaw crusher, stamp mill, hammer mill or the like, and then washed with a neutral or acidic solution.
As a neutral solution used here, it is preferable to use water. The type of water that can be used is not particularly limited, but demineralized water or distilled water is preferred. The electric conductivity of the water used is usually 0.001 mS / m or more, preferably 0.01 mS / m, and usually 1 mS / m or less, preferably 0.1 mS / m or less. The temperature of water is usually preferably room temperature (about 25 ° C.), preferably 40 ° C. or higher, more preferably 50 ° C. or higher, preferably 90 ° C. or lower, more preferably 80 ° C. or lower. By using water, it is possible to reduce the number of times of washing for obtaining the target phosphor.

  An acidic aqueous solution is preferable as the acidic solution. Although there is no restriction | limiting in particular in the kind of acidic aqueous solution, The aqueous solution which diluted 1 type, or 2 or more types of mineral acids, such as hydrochloric acid and a sulfuric acid, can be used. The acid concentration of the acid aqueous solution is usually 0.1 mol / l or more, preferably 0.2 mol / l or more, and usually 5 mol / l or less, preferably 2 mol / l or less. It is preferable to use an acidic aqueous solution instead of a neutral aqueous solution in terms of the efficiency of reducing the amount of dissolved ions of the phosphor. However, if the acid concentration of the acid aqueous solution used for this washing exceeds 5 mol / l, the phosphor surface is removed. Since there exists a possibility that it may melt | dissolve, it is not preferable, and if it is less than 0.1 mol / l, the effect using an acid is not fully acquired. In the present invention, a highly corrosive acid such as hydrofluoric acid is not required as the acid.

  Although there is no restriction | limiting in particular as the washing | cleaning method of fluorescent substance, Specifically, the obtained fluorescent substance particle is put into the above-mentioned neutral or acidic solution (it may be hereafter called a "cleaning medium"). A method of dispersing by stirring for a predetermined time and then separating the phosphor particles into a solid and a liquid can be mentioned.

  There is no particular limitation on the stirring method for cleaning the phosphor, and it is sufficient that the phosphor particles can be uniformly dispersed. For example, a chip stirrer or a stirrer can be used.

The amount of the cleaning medium is not particularly limited, but if it is too small, a sufficient cleaning effect cannot be obtained. If it is excessively large, a large amount of cleaning medium is required, which is unreasonable. It is preferably at least double, particularly at least 5 times, at most 1000 times, particularly at most 100 times.
The stirring time is 10 minutes in the examples described later, but may be any time that can sufficiently bring the phosphor and the above-described cleaning medium into contact with each other, and is usually 1 minute or more and 1 hour or less. is there.

  There is no restriction | limiting in particular in the method of solid-liquid-separating a washing | cleaning medium and fluorescent substance particle, For example, filtration, centrifugation, a decantation etc. are mentioned.

  However, the method of cleaning the phosphor particles is not particularly limited to the solid-liquid separation after dispersion by stirring the phosphor particles in the cleaning medium as described above, and the method of exposing the phosphor particles to the fluid of the cleaning medium, etc. It may be.

Moreover, you may perform such a washing | cleaning process in multiple times.
In addition, when performing a plurality of washing steps, water washing and washing with an acid aqueous solution may be performed in combination, but in that case, after washing with an acid aqueous solution in order to prevent adhesion of acid to the phosphor, It is preferable to perform water washing. Further, after washing with water, washing with an acid aqueous solution and then washing with water may be performed.
Moreover, when performing the washing | cleaning process in multiple times, you may put the above-mentioned grinding | pulverization process and classification process between washing | cleaning processes.

In the present invention, the phosphor is washed by performing the following water dispersion test on the washed phosphor until the electrical conductivity of the supernatant liquid becomes a predetermined value or less.
That is, the phosphor after washing is pulverized or pulverized by a dry ball mill or the like as necessary, classified by a sieve or a water tank, and sized to a desired weight median diameter, and then 10 wt. The phosphor particles having a specific gravity heavier than that of water are naturally precipitated by stirring and dispersing in double water for a predetermined time, for example, 10 minutes, and then allowing to stand for 1 hour. The electrical conductivity of the supernatant liquid at this time is measured, and the above-mentioned washing is performed as necessary until the electrical conductivity is usually 50 mS / m or less, preferably 10 mS / m or less, and most preferably 5 mS / m or less. Repeat the operation.

  The water used for the water dispersion test of the phosphor is not particularly limited, but desalted water or distilled water is preferable as in the case of the above-mentioned cleaning medium, and the electric conductivity is usually 0.001 mS / m or more. , Preferably 0.01 mS / m or more, and usually 1 mS / m or less, preferably 0.1 mS / m or less. The temperature of the water used for the water dispersion test of the phosphor is usually room temperature (about 25 ° C.).

  By carrying out such washing, the phosphor of the present invention in which the electrical conductivity of the supernatant obtained by dispersing the phosphor in water 10 times by weight and allowing it to stand for 1 hour is 50 mS / m or less is obtained. Can be obtained.

  In addition, the electrical conductivity of the supernatant liquid in the phosphor aqueous dispersion test can be measured using an electrical conductivity meter “EC METER CM-30G” manufactured by Toa Decay Co., Ltd.

The electrical conductivity of the supernatant liquid in the phosphor aqueous dispersion test increases as a result of dissolution of some of the constituent components of the phosphor into ions as a result of dissolution. That the electrical conductivity of the supernatant liquid is low means that the content of the water-soluble component in the phosphor is small.
As described above, the oxygen content of the phosphor is also reduced by the above-described cleaning, because the impurity phase containing oxygen, for example, a hydroxide formed by hydrolysis of poorly crystalline nitride is removed. Inferred.

For example, in the SCASN phosphor described above, it can be estimated that the following occurs in the cleaning process.
(1) Nitride having poor crystallinity is hydrolyzed to form a hydroxide such as Sr (OH) ₂ and dissolves in water. When washed with warm water or dilute acid, they are efficiently removed and the electrical conductivity is lowered. On the other hand, if the acid concentration is too high, or if exposed to an acid for a long time, the parent SCASN phosphor itself may be decomposed, which is not preferable.
(2) Boron mixed from a boron nitride (BN) crucible used during firing in the nitriding process of the alloy forms a water-soluble boron nitrogen-alkaline earth compound and mixes into the phosphor. Disassembled and removed.

  The reason for the improvement in luminous efficiency and brightness in the present invention is not completely clarified, but since a slight ammonia odor is felt when the phosphor immediately after firing is taken out into the air, this unreacted by washing. Alternatively, it is considered that a portion generated by decomposition of a portion with insufficient reaction was removed.

  In many cases, the phosphor is used as a powder and is used in a state dispersed in another dispersion medium. Therefore, in order to facilitate these dispersing operations, various surface treatments are performed on phosphors as a normal method among those skilled in the art. In the case of the phosphor that has been subjected to such surface treatment, it is appropriate to understand that the stage before the surface treatment is performed is the phosphor according to the present invention.

  After the washing, the phosphor is dried until it has no adhering moisture and is used.

[Characteristics of phosphor]
(Powder X-ray diffraction pattern)
In the case of the SCASN phosphor, by performing the above-described cleaning operation, the peak intensity (high 2θ = 33.2 ± 0.2 °) of the powder X-ray diffraction peak using the Cu—Kα ray (1.54184Å) is high. The ratio tends to decrease. This indicates that impurities are removed from the phosphor by washing.

In the powder X-ray diffraction pattern of the SCASN phosphor, the peak height I _{p of} 2θ = 33.2 ° ± 0.2 ° with respect to the height I _max of the strongest peak in the range of 2θ of 35.5 ° to 37 °. When I = (I _p × 100) / I _max , I is usually 15% or less, preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. Here, the peak intensity is a value obtained by performing background correction.

(Emission spectrum)
For example, the Eu-activated SCASN phosphor obtained by the present invention has the following characteristics when an emission spectrum is measured when excited with light having a wavelength of 465 nm, in view of the use as an orange to red phosphor. Is preferred.

  First, the phosphor of the present invention preferably has a peak wavelength λp (nm) in the above-described emission spectrum of usually greater than 590 nm, particularly 600 nm or more, and usually 650 nm or less, particularly 640 nm or less. If this emission peak wavelength λp is too short, it tends to be yellowish, whereas if it is too long, it tends to be dark reddish, both of which are not preferred because the characteristics as orange or red light may be reduced.

  In addition, the phosphor of the present invention has a full width at half maximum (hereinafter, abbreviated as “FWHM” where appropriate) in the above-described emission spectrum, which is usually larger than 50 nm, particularly 70 nm or more, and even 75 nm. In addition, the thickness is preferably less than 120 nm, more preferably 100 nm or less, and even more preferably 90 nm or less. 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.

  In order to excite the phosphor of the present invention with light having a wavelength of 465 nm, for example, a GaN light emitting diode can be used. Moreover, 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-value width can be carried out using an apparatus such as a fluorescence measuring apparatus manufactured by JASCO Corporation.

(Weight median diameter D ₅₀ )
The phosphor of the present invention preferably has a weight median diameter D ₅₀ in the range of usually 3 μm or more, especially 5 μm or more, and usually 30 μm or less, especially 20 μm or less. When the weight-average median diameter D ₅₀ is too small, and the luminance decreases tends to phosphor particles tend to aggregate undesirably. On the other hand, when the weight-average median diameter D ₅₀ is too large, there is a tendency for blockage, such as coating unevenness and dispenser is not preferable.
The weight-average median diameter D ₅₀ of the phosphor in the present invention, for example, can be measured using a device such as a laser diffraction / scattering particle size distribution measuring apparatus.

(Other)
The phosphor of the present invention is more preferable as its internal quantum efficiency is higher. The value is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more. If the internal quantum efficiency is low, the light emission efficiency tends to decrease, which is not preferable.

  The phosphor of the present invention is preferably as its absorption efficiency is high. The value is usually 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more. If the absorption efficiency is low, the light emission efficiency tends to decrease, which is not preferable.

[Use of phosphor]
The phosphor of the present invention can be suitably used for various light-emitting devices (hereinafter referred to as “light-emitting device of the present invention”) by taking advantage of its high luminance and high color rendering properties. For example, when the phosphor of the present invention is an orange or red phosphor, a high color rendering white light emitting device can be realized by combining a green phosphor, a blue phosphor, and the like. 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.

[Phosphor-containing composition]
When the phosphor of the present invention is used for a light emitting device or the like, 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.

  The liquid medium that can be used in the phosphor-containing composition of the present invention is a liquid medium that exhibits liquid properties under the desired use conditions, and that suitably disperses the phosphor of the present invention and does not cause undesirable reactions. If there is, it is possible to select an arbitrary one according to the purpose. Examples of the liquid medium include a thermosetting resin and a photocurable resin before curing, and examples thereof include an addition reaction type silicone resin, a condensation reaction type silicone resin, a modified silicone resin, and an epoxy resin. In addition, a solution obtained by hydrolytic polymerization of a solution containing an inorganic material, for example, a ceramic precursor polymer or a metal alkoxide by a sol-gel method can be used. These liquid media may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The amount of the liquid medium used may be appropriately adjusted according to the application, etc., but in general, the weight ratio of the liquid medium to the phosphor of the present invention is usually 3% by weight or more, preferably 5% by weight or more, Moreover, it is 30 weight% or less normally, Preferably it is the range of 15 weight% or less.

  In addition to the phosphor of the present invention and the liquid medium, the phosphor-containing composition of the present invention may contain other optional components depending on its use and the like. Examples of other components include a diffusing agent, a thickener, a bulking agent, and an interference agent. Specifically, silica-based fine powder such as Aerosil, alumina and the like can be mentioned.

[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 as an excitation light source and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body.

(First luminous body)
The 1st light-emitting body in the light-emitting device of this invention light-emits the light which excites the 2nd light-emitting body mentioned later. The light emission wavelength of the first light emitter is not particularly limited as long as it overlaps with the absorption wavelength of the second light emitter described later, and a light emitter having a wide light emission wavelength region can be used. Usually, an illuminant having an emission wavelength from the near ultraviolet region to the blue region is used, and the specific numerical value is usually 300 nm or more, preferably 330 nm or more, and usually 500 nm or less, preferably 480 nm or less. A light emitter having the following is used. As the first light emitter, a semiconductor light emitting element is generally used. Specifically, a light emitting diode (hereinafter abbreviated as “LED” as appropriate) or a semiconductor laser diode (semiconductor laser diode). Hereinafter, it is abbreviated as “LD” where appropriate).

Among these, as the first light emitter, a GaN LED or LD using a GaN compound semiconductor is preferable. This is because GaN-based LEDs and LDs have significantly higher light emission output and external quantum efficiency than SiC-based LEDs that emit light in this region, and are extremely bright with very low power when combined with the phosphor. This is because 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 preferable.

(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 light from the first light emitter described above, and a first phosphor (orange or red phosphor) to be described later is used. A second phosphor (a green phosphor, a blue phosphor, etc.) to be described later is contained as appropriate according to the application.

There is no particular limitation on the composition of the phosphor, _Y 2 _O 3 is a host _crystal, Zn 2 metal oxide represented by SiO ₄ and the _like, a metal nitride typified by Sr 2 _Si 5 _{N 8} such, Ca ₅ (PO ₄ ) ₃ Cl etc. and phosphates such as ZnS, SrS, CaS etc., Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, A combination of rare earth metal ions such as Tm and Yb and metal ions such as Ag, Cu, Au, Al, Mn, and Sb as activators or coactivators is preferred.

Preferred examples of the crystal matrix include sulfides such as (Zn, Cd) S, SrGa ₂ S ₄ , SrS, and ZnS, oxysulfides such as Y ₂ O ₂ S, and (Y, Gd) ₃ Al ₅ O. ₁₂ , YAlO ₃ , BaMgAl ₁₀ O ₁₇ , (Ba, Sr) (Mg, Mn) Al ₁₀ O ₁₇ , (Ba, Sr, Ca) (Mg, Zn, Mn) Al ₁₀ O ₁₇ , BaAl ₁₂ O ₁₉ , CeMgAl ₁₁ O ₁₉ , (Ba, Sr, Mg) O.Al ₂ O ₃ , BaAl ₂ Si ₂ O ₈ , SrAl ₂ O ₄ , Sr ₄ Al ₁₄ O ₂₅ , aluminate such as Y ₃ Al ₅ O ₁₂ , Y Silicates such as ₂ SiO ₅ and Zn ₂ SiO ₄ , oxides such as SnO ₂ and Y ₂ O ₃ , borates such as GdMgB ₅ O ₁₀ and (Y, Gd) BO ₃ , Ca ₁₀ (PO ₄ ) ₆ ( _{F, Cl) 2, (Sr} , Ca, Ba, g) ₁₀ (PO ₄₎ such as ₆ Cl _{2 halophosphate,} Sr ₂ P _{2 O 7,} can be cited (La, Ce) phosphate PO _4, etc. and the like.

  However, the crystal matrix and the activator element or coactivator element are not particularly limited in element composition, and can be partially replaced with elements of the same family, and the obtained phosphor is light in the near ultraviolet to visible region. Any material that absorbs and emits visible light can be used.

Specifically, the following phosphors can be used, but these are merely examples, and phosphors that can be used in the present invention are not limited to these. In the following examples, phosphors that differ only in part of the structure are omitted as appropriate. For example, “Y ₂ SiO ₅ : Ce ³⁺ ”, “Y ₂ SiO ₅ : Tb ³⁺ ” and “Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ ” are changed to “Y ₂ SiO ₅ : Ce ³⁺ , Tb ³⁺ ”, “ “La ₂ O ₂ S: Eu”, “Y ₂ O ₂ S: Eu” and “(La, Y) ₂ O ₂ S: Eu” are collectively shown as “(La, Y) ₂ O ₂ S: Eu”. ing. Omitted parts are shown separated by commas (,).

<First phosphor (orange to red phosphor)>
The second light emitter in the light emitting device of the present invention contains at least the above-described phosphor of the present invention as an orange to 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, one or more other orange or red phosphors may be used in combination as the first phosphor.

  Illustrating the specific wavelength range of the fluorescence emitted by the phosphor emitting red fluorescence (hereinafter referred to as “red phosphor” as appropriate), the peak wavelength is usually 570 nm or more, preferably 580 nm or more, and usually 700 nm or less. Preferably, it is 680 nm or less.

The orange or red phosphor other than the phosphor of the present invention is composed of, for example, fractured particles having a red fracture surface and emits light in a red region (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu Europium-activated alkaline earth silicon nitride phosphor expressed by the following formula: growth particles having a substantially spherical shape as a regular crystal growth shape, and emitting light in the red region (Y, La, Gd, Lu) ₂ Examples include europium activated rare earth oxychalcogenide phosphors represented by O ₂ S: Eu.

  Furthermore, the oxynitride and / or acid containing at least one element selected from the group consisting of Ti, Zr, Hf, Nb, Ta, W, and Mo described in JP-A-2004-300247 A phosphor containing a sulfide and containing an oxynitride having an alpha sialon structure in which a part or all of the Al element is substituted with a Ga element can also be used in this embodiment. These are phosphors containing oxynitride and / or oxysulfide.

In addition, examples of red phosphors include Eu-activated oxysulfide phosphors such as (La, Y) ₂ O ₂ S: Eu, Y (V, P) O ₄ : Eu, Y ₂ O ₃ : Eu, and the like. Eu-activated oxide phosphor, (Ba, Sr, Ca, Mg) 2 SiO 4: Eu, Mn, (Ba, Mg) 2 SiO 4: Eu, Eu such as Mn, Mn-activated silicate phosphor, (Ca, Sr) S: Eu-activated sulfide phosphors such as Eu, YAlO ₃ : Eu-activated aluminate phosphors such as Eu, LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu, Ca ₂ Y ₈ ( SiO ₄ ) ₆ O ₂ : Eu, (Sr, Ba, Ca) ₃ SiO ₅ : Eu, Sr ₂ BaSiO ₅ : Eu-activated silicate phosphor such as Eu, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce _{, (Tb, Gd) 3 Al} 5 O 12: Ce -activated aluminate phosphor such as Ce, (Ca, Sr, Ba ) 2 Si 5 _{8: Eu, (Mg, Ca} , Sr, Ba) SiN 2: Eu, (Mg, Ca, Sr, Ba) AlSiN 3: Eu -activated nitride phosphor such as Eu, (Mg, Ca, Sr , Ba) AlSiN ₃ : Ce-activated nitride phosphor such as Ce, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, Mn-activated halophosphate phosphor such as Eu and Mn, (Ba ₃ Mg) Si ₂ O ₈ : Eu, Mn, (Ba, Sr, Ca, Mg) ₃ (Zn, Mg) Si ₂ O ₈ : Eu, Mn activated silicate phosphor such as Eu, Mn, 3.5MgO 0.5MgF ₂ · GeO ₂ : Mn-activated germanate phosphor such as Mn, Eu-activated oxynitride phosphor such as Eu-activated α-sialon, (Gd, Y, Lu, La) ₂ O ₃ : eu, eu Bi, etc., Bi-activated oxide phosphor, (Gd, Y, Lu, La) 2 O 2 S: Eu, Bi Of Eu, Bi Tsukekatsusan sulfide phosphor, (Gd, Y, Lu, La) VO 4: Eu, Eu Bi, etc., Bi-activated vanadate _phosphor, SrY ₂ S 4: _Eu, such as Ce Eu, Ce activated sulfide phosphor, Ce activated sulfide phosphor such as CaLa ₂ S ₄ : Ce, (Ba, Sr, Ca) MgP ₂ O ₇ : Eu, Mn, (Sr, Ca, Ba, Mg) , Zn) ₂ P ₂ O ₇ : Eu, Mn activated phosphor phosphor such as Eu, Mn, (Y, Lu) ₂ WO ₆ : Eu, Mo activated tungstate phosphor such as Eu, Mo, (Ba, Sr, Ca) _x Si _y N _z : Eu, Ce activated nitride phosphor such as Eu, Ce (where x, y, z are integers of 1 or more), (Ca, Sr, Ba, _{mg) 10 (PO 4) 6} (F, Cl, Br, OH): Eu, Eu such as Mn, Mn-activated halophosphate phosphor, ((Y, Lu, d, Tb) can also be used such as _{1-x Sc x Ce y)} 2 (Ca, Mg) 1-r (Mg, Zn) 2 + r Si z-q GeqO Ce -activated silicate phosphors _{12 + [delta],} etc. .

  As the red phosphor, β-diketonate, β-diketone, aromatic carboxylic acid, or a red organic phosphor composed of a rare earth element ion complex having an anion such as 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 pigment, Lake pigments, azo pigments, quinacridone pigments, anthracene pigments, isoindoline pigments, isoindolinone pigments, phthalocyanine pigments, triphenylmethane basic dyes, indanthrone pigments, indophenol pigments, It is also possible to use a cyanine pigment or a dioxazine pigment.

Among the red phosphors, those having a peak wavelength in the range of 580 nm or more, preferably 590 nm or more, and 620 nm or less, preferably 610 nm or less can be suitably used as the orange phosphor. Examples of such orange phosphors include (Sr, Ba) ₃ SiO ₅ : Eu, (Sr, Mg) ₃ (PO ₄ ) ₂ : Sn ^{2+, and the} like.

<Second phosphor>
Furthermore, the 2nd light-emitting body in the light-emitting device of this invention may contain the fluorescent substance from which an emission wavelength differs from the above-mentioned 1st fluorescent substance (phosphor of this invention) according to the use. (This is hereinafter referred to as “second phosphor” as appropriate). As the second phosphor, one kind of phosphor may be used alone, or two or more kinds of phosphors may be used in any combination and ratio.

  Examples of the second phosphor used in combination with the first phosphor (orange to red phosphor) include phosphors emitting green light (hereinafter referred to as “green phosphors” as appropriate) and blue light emission. And a phosphor that emits light (hereinafter referred to as “blue phosphor” as appropriate).

{Green phosphor}
When a specific wavelength range of fluorescence emitted by a phosphor emitting green fluorescence (hereinafter referred to as “green phosphor” as appropriate) is exemplified, the peak wavelength is usually 490 nm or more, preferably 500 nm or more, and usually 570 nm or less. Preferably, it is 550 nm or less.

As such a green phosphor, for example, a europium-activated alkali represented by (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu that is composed of fractured particles having a fracture surface and emits light in the green region. Europium-activated alkaline earth silicate composed of an earth silicon oxynitride phosphor, broken particles having a fracture surface, and emitting in the green region (Ba, Ca, Sr, Mg) ₂ SiO ₄ : Eu System phosphors and the like.

In addition, as the green phosphor, Eu-activated aluminate phosphor such as Sr ₄ Al ₁₄ O ₂₅ : Eu, (Ba, Sr, Ca) Al ₂ O ₄ : Eu, (Sr, Ba) Al ₂ Si ₂ O ₈ : Eu, (Ba, Mg) ₂ SiO ₄ : Eu, (Ba, Sr, Ca, Mg) ₂ SiO ₄ : Eu, (Ba, Sr, Ca) ₂ (Mg, Zn) Si ₂ O ₇ : Eu activated silicate phosphor such as Eu, Y ₂ SiO ₅ : Ce, Tb activated silicate phosphor such as Ce, Tb, Sr ₂ P ₂ O ₇ —Sr ₂ B ₂ O ₅ : Eu such as Eu Activated boric acid phosphor, Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu activated halosilicate phosphor such as Eu, Zn ₂ SiO ₄ : Mn activated silicate phosphor such as Mn, CeMgAl ₁₁ O _{19: Tb, Y 3 Al 5} O 12: Tb -activated aluminate Sanshiohotaru of Tb such _{Body, Ca 2 Y 8 (SiO 4} ) 6 O 2: Tb, La 3 Ga 5 SiO 14: Tb -activated silicate phosphors such as Tb, (Sr, Ba, Ca ) Ga 2 S 4: Eu, Tb, Eu, Tb, Sm activated thiogallate phosphors such as Sm, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Y, Ga, Tb, La, Sm, Pr, Lu) ₃ (Al, Ga) ₅ O ₁₂ : Ce-activated aluminate phosphor such as Ce, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, Ca ₃ (Sc, Mg, Na, Li) ₂ Si ₃ O ₁₂ : Ce-activated silicate such as Ce Phosphor, Ce activated oxide phosphor such as CaSc ₂ O ₄ : Ce, SrSi ₂ O ₂ N ₂ : Eu, (Sr, Ba, Ca) Si ₂ O ₂ N ₂ : Eu, Eu activated β sialon, Eu-activated oxynitride phosphors such as Eu-activated α sialon, BaMgAl ₁₀ O ₁₇ : Eu, Mn activated aluminate phosphor such as Eu, Mn, SrAl ₂ O ₄ : Eu activated aluminate phosphor such as Eu, (La, Gd, Y) ₂ O ₂ S: Tb such as Tb Activated oxysulfide phosphor, LaPO ₄ : Ce, Tb activated phosphate phosphor such as Ce, Tb, Sulfide phosphor such as ZnS: Cu, Al, ZnS: Cu, Au, Al, (Y, Ga, Lu, Sc, La) BO 3: Ce, Tb, Na 2 Gd 2 B 2 O 7: Ce, Tb, (Ba, Sr) 2 (Ca, Mg, Zn) B 2 O 6: K, Ce, Ce, Tb activated borate phosphor such as Tb, Eu, Mn activated halosilicate phosphor such as Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu, Mn, (Sr, Ca, Ba) (Al, _{Ga, in) 2 S 4:} Eu activated thioaluminate phosphor or thiogallate phosphor such as _{Eu, (Ca, Sr) 8} (M _{, Zn) (SiO 4) 4} Cl 2: Eu, it is also possible to use Eu such as Mn, a Mn-activated halo-silicate phosphors and the like.

  In addition, as the green phosphor, it is also possible to use a pyridine-phthalimide condensed derivative, a benzoxazinone-based, a quinazolinone-based, a coumarin-based, a quinophthalone-based, a naltalimide-based fluorescent pigment, or an organic phosphor such as a terbium complex. is there.

{Blue phosphor}
Illustrating the specific wavelength range of the fluorescence emitted by a phosphor emitting blue fluorescence (hereinafter referred to as “blue phosphor” as appropriate), the peak wavelength is usually 420 nm or more, preferably 440 nm or more, and usually 480 nm or less. Preferably, it is 470 nm or less.

As such a blue phosphor, a europium-activated barium magnesium aluminate system represented by BaMgAl ₁₀ O ₁₇ : Eu, which is composed of growing particles having a substantially hexagonal shape as a regular crystal growth shape and emits light in a blue region. Europium activated halo represented by (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ Cl: Eu, which is composed of phosphors and growing particles having a substantially spherical shape as a regular crystal growth shape, and emits light in the blue region. Calcium phosphate-based phosphor, composed of growing particles having a cubic shape as a regular crystal growth shape, emits light in the blue region, and is activated by europium represented by (Ca, Sr, Ba) ₂ B ₅ O ₉ Cl: Eu Consists of alkaline earth chloroborate phosphors and fractured particles with fractured surfaces, and emits light in the blue-green region Examples include europium-activated alkaline earth aluminate-based phosphors represented by (Sr, Ca, Ba) Al ₂ O ₄ : Eu or (Sr, Ca, Ba) ₄ Al ₁₄ O ₂₅ : Eu.

In addition, as the blue phosphor, Sn-activated phosphate phosphors such as Sr ₂ P ₂ O ₇ : Sn, Sr ₄ Al ₁₄ O ₂₅ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, BaAl ₈ O ₁₃ : Eu-activated aluminate phosphors such as Eu, Ce-activated thiogallate phosphors such as SrGa ₂ S ₄ : Ce, CaGa ₂ S ₄ : Ce, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu activated aluminate phosphor such as Eu, Tb, Sm, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, Mn activated aluminate phosphor such as Eu, Mn, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Ba, Sr, Ca) ₅ (PO ₄ ) ₃ (Cl, F, Br, OH): Eu activation such as Eu, Mn, Sb halophosphate phosphor, BaAl _{Si 2 O 8: Eu, (} Sr, Ba) 3 MgSi 2 O 8: Eu -activated silicate phosphors such as _{Eu, Sr 2 P 2 O 7} : Eu -activated phosphate phosphor such as Eu, ZnS: Sulfide phosphors such as Ag, ZnS: Ag, Al, etc. Y ₂ SiO ₅ : Ce-activated silicate phosphors such as Ce, tungstate phosphors such as CaWO ₄ , (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 such as Eu, Mn-activated borate phosphate It is also possible to use a salt phosphor, an Eu-activated halosilicate phosphor such as Sr ₂ Si ₃ O ₈ .2SrCl ₂ : Eu, or the like.

  In addition, as the blue phosphor, for example, naphthalic acid imide-based, benzoxazole-based, styryl-based, coumarin-based, pyralizone-based, triazole-based compound fluorescent dyes, thulium complexes and other organic phosphors can be used. .

  In addition, the above-mentioned fluorescent substance may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

(Selection of second phosphor)
In the light emitting device of the present invention, the presence / absence and type of the second phosphor (red phosphor, blue phosphor, green phosphor, etc.) described above may be appropriately selected according to the use of the light emitting device. . For example, when the light emitting device of the present invention is configured as an orange or red light emitting device, only the first phosphor (orange or red phosphor) may be used, and the second phosphor is usually used. Is unnecessary.

  On the other hand, when the light-emitting device of the present invention is configured as a light-emitting device that emits white light, the first light-emitting body, the first phosphor (orange or red phosphor), and a desired white light are obtained. What is necessary is just to combine a 2nd fluorescent substance appropriately. 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) to (iii) are included.

(I) A blue phosphor (such as a blue LED) is used as the first phosphor, a red phosphor (such as the phosphor of the present invention) is used as the first phosphor, and green fluorescence is used as the second phosphor. Use the body.

(Ii) A near ultraviolet light emitter (near ultraviolet LED or the like) is used as the first light emitter, a red phosphor (such as the phosphor of the present invention) is used as the first phosphor, and the second phosphor is used as the second phosphor. A blue phosphor and a green phosphor are used in combination.

(Iii) A blue phosphor (such as a blue LED) is used as the first phosphor, an orange phosphor (such as the phosphor of the present invention) is used as the first phosphor, and green fluorescence is used as the second phosphor. Use the body.

(Physical properties of the second phosphor)
The weight median diameter of the second phosphor used in the light emitting device of the present invention is usually in the range of 10 μm or more, especially 15 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.

(Configuration of light emitting device)
The light-emitting device of the present invention is only required to include the first light-emitting body and the second light-emitting body described above, and other configurations are not particularly limited. Usually, the above-described first light-emitting element is formed on an appropriate frame. A body 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 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 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.

  As a sealing material used, a thermoplastic resin, a thermosetting resin, a photocurable resin, etc. are mentioned normally. Specifically, methacrylic resin such as methyl polymethacrylate; styrene resin such as polystyrene and styrene-acrylonitrile copolymer; polycarbonate resin; polyester resin; phenoxy resin; butyral resin; polyvinyl alcohol; ethyl cellulose, cellulose acetate, cellulose Cellulose resins such as acetate butyrate; epoxy resins; phenol resins; silicone resins and the like. 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.

(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 resin 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 light-emitting substance (the first phosphor and the second phosphor) in the phosphor-containing part 4, and another part is The light is emitted from the light emitting device 1 in a predetermined direction.

  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, and 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. 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, and the sum of the light emitted from the blue LED 3 and the light emitted from the phosphor light-emitting 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. An epoxy resin can be mainly used for the mold part 7.

  FIG. 2 is a schematic cross-sectional view showing an embodiment of a surface emitting illumination device incorporating the light emitting device 1 shown in FIG. In FIG. 2, 8 is a surface emitting illumination device, 9 is a diffusion plate, and 10 is a holding case.

  This surface-emitting illuminating device 8 has a large number of light-emitting devices 1 on the bottom surface of a rectangular holding case 10 whose inner surface is light-opaque such as a white smooth surface, and a power source for driving the light-emitting device 1 on the outside thereof. And a circuit or the like (not shown). In order to make the light emission uniform, a diffusion plate 9 such as an acrylic plate made of milky white is fixed to a portion corresponding to the lid portion of the holding case 10.

  Then, the surface-emitting illumination device 8 is driven to apply blue voltage to the blue LED 3 of the light-emitting device 1 to emit blue light or the like. Part of the emitted light is absorbed in the phosphor-containing portion 4 by the phosphor of the present invention, which is a wavelength conversion material, and another phosphor added as necessary, and converted into light having a longer wavelength. Light emission with high luminance is obtained by mixing with blue light or the like that has not been absorbed. This light passes through the diffusion plate 9 and is emitted upward in the drawing, and illumination light with uniform brightness is obtained within the surface of the diffusion plate 9 of the holding case 10.

  In the light emitting device of the present invention, in particular, when a surface emitting type light source is used as the excitation light source (first light emitter), the phosphor-containing portion (second light emitter) is preferably formed into a film. That is, since the cross-sectional area of the light from the surface-emitting type illuminant is sufficiently large, if the second illuminant is formed into a film shape in the direction of the cross section, the irradiation cross-sectional area from the first illuminant to the phosphor is increased. Since it becomes large per fluorescent substance unit amount, the intensity | strength of light emission from fluorescent substance can be made larger.

  Further, when a surface-emitting type is used as the first light emitter and a film-like one is used as the second light emitter, the second light emitter directly in the form of a film on the light-emitting surface of the first light emitter. It is preferable to have a shape in which is contacted. Contact here refers to creating a state in which the first light emitter and the second light emitter are in perfect contact with each other without air or gas. As a result, it is possible to avoid a light amount loss in which light from the first light emitter is reflected by the film surface of the second light emitter and oozes out, so that the light emission efficiency of the entire apparatus can be improved.

  FIG. 3 is a schematic perspective view showing an example of a light-emitting device using a surface-emitting type as the first light emitter and applying a film-like one as the second light-emitting body. In FIG. 3, 11 is a film-like second light emitter having the phosphor, 12 is a surface-emitting GaN-based LD as the first light emitter, and 13 is a substrate. In order to create a state where they are in contact with each other, the LD of the first light emitter 12 and the second light emitter 11 may be formed separately, and the surfaces may be brought into contact with each other by an adhesive or other means. Then, the second light emitter 11 may be formed (molded) on the light emitting surface of the first light emitter 12. As a result, the first light emitter 12 and the second light emitter 11 can be brought into contact with each other.

[Applications of light emitting devices]
The use of the light-emitting device of the present invention is not particularly limited, and can be used in various fields where a normal light-emitting device is used. However, since it has high luminance and high color rendering properties, image display is particularly important. It is particularly preferably used as a light source for a device or a lighting device. In addition, when using the light-emitting device of this invention as a light source of an image display apparatus, using with a color filter is preferable.

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.
In each Example and each Comparative Example described later, various evaluations were performed by the following methods.

<Electric conductivity of supernatant liquid in water dispersion test>
After classification with a sieve and sizing to a median diameter of 9 μm (however, when the weight median diameter of the washed phosphor particles is 9 μm, this operation is not performed), the phosphor particles are adjusted to the weight of the phosphor. The mixture was placed in 10 times the amount of water and dispersed by stirring for 10 minutes using a stirrer. After standing for 1 hour, it was confirmed that the phosphor had settled, and the electrical conductivity of the supernatant was measured.
The electric conductivity was measured using an electric conductivity meter “EC METER CM-30G” manufactured by Toa Decay. Washing and measurement were performed at room temperature.
In addition, the electrical conductivity of the water used for the washing | cleaning and the water dispersion test of fluorescent substance in each Example and each comparative example is 0.03 mS / m.

<Emission spectrum, chromaticity coordinates, and brightness>
In a fluorescence measuring apparatus manufactured by JASCO Corporation, a 150 W xenon lamp was used as an excitation light source. The light from the xenon lamp was passed through a diffraction grating spectrometer having a focal length of 10 cm, and only the light of 450 nm to 475 nm was irradiated to the phosphor through the optical fiber. The light generated by the irradiation of the excitation light was dispersed with a diffraction grating spectrometer having a focal length of 25 cm, and the emission intensity of each wavelength of 300 nm to 800 nm was measured with a multichannel CCD detector “C7041” manufactured by Hamamatsu Photonics. Subsequently, an emission spectrum was obtained through signal processing such as sensitivity correction by a personal computer.
Chromaticity coordinates x and y in the XYZ color system defined by JIS Z8701 were calculated from data in the wavelength region of 480 nm to 800 nm of this emission spectrum.
Moreover, the relative brightness | luminance which made the value of the stimulus value Y of the fluorescent substance in the reference example 1 mentioned later 100% from the stimulus value Y in the XYZ color system calculated based on JISZ8724 was calculated.
The chromaticity coordinates and the luminance were measured by cutting the excited blue light.

<Chemical composition>
ICP emission spectroscopy (Inductively
Coupled Plasma-Atomic Emission Spectrometry; hereinafter referred to as “ICP method”. ) Using an ICP chemical analyzer “JY 38S” manufactured by Jobibon.

_{<Weight-average} median diameter _{D 50} of the phosphor>
Before the measurement, an ultrasonic disperser (manufactured by Kaijo Co., Ltd.) was used, the frequency was 19 KHz, the intensity of the ultrasonic wave was 5 W, and the sample was dispersed with ultrasonic waves for 25 seconds. In addition, in order to prevent re-aggregation, water to which a small amount of a surfactant was added was used for the dispersion.
In the measurement of the weight median diameter, a laser diffraction / scattering particle size distribution measuring device (manufactured by Horiba, Ltd.) was used.

<Powder X-ray diffraction measurement>
The details of the powder X-ray diffraction measurement conditions are as follows.
Measuring apparatus: PANALYTIC PW1700 type powder X-ray diffraction measurement conditions:
X-ray source: Cu—Kα ray (λ = 1.54184Å),
Output setting: 40 kV, 30 mA
Optical conditions during measurement: Divergent slit = 1 °
Scattering slit = 1 °
Receiving slit = 0.2mm
Diffraction peak position 2θ (Diffraction angle)
Measurement range: 2θ = 10 to 89.95 °
Scanning speed: 0.05 degree (2θ) / sec, continuous scanning Sample preparation: Sample molding jig (manufactured by Philips, formerly milled manually using an agate mortar)
Sample holder: PANALYTIC PW1781 / 00 type Sample part size Outer diameter: 53mm
Inner diameter: 27mm
Depth: 2.6mm

  In the following, the simple metals used for the alloy raw materials are all high-purity products having an impurity concentration of 0.01 mol% or less. In addition, as for the shape of the raw metal, Sr is a lump and the others are granular.

(Synthesis Example 1)
The fired products used in Examples 1 to 3 and Comparative Example 1 were synthesized by the following method.
Each metal was weighed so that the metal element composition ratio was Al: Si = 1: 1 (molar ratio), and after melting the raw material metal using a high-frequency induction melting furnace in an argon atmosphere using a graphite crucible, the crucible Was poured into a mold and solidified to obtain an alloy (mother alloy) having an element ratio of Al: Si = 1: 1.

  The mother alloy and other raw materials were weighed so that Eu: Sr: Ca: Al: Si = 0.008: 0.792: 0.2: 1: 1 (molar ratio). After evacuating the inside of the furnace, the evacuation was stopped, and the furnace was filled with argon to a predetermined pressure. In this furnace, after melting the mother alloy in the calcia crucible, and then adding Sr, Eu, and Ca, and confirming that the molten metal with all components melted is agitated by the induced current, a copper mold that is water cooled from the crucible The molten metal was poured into a (plate shape with a thickness of 40 mm) and solidified.

The obtained plate-like alloy having a thickness of 40 mm was subjected to composition analysis by ICP method. About 10g was sampled from one point near the center of gravity of the plate and one point near the end face of the plate, and elemental analysis was performed by ICP method.
Central part of plate Eu: Sr: Ca: Al: Si = 0.000: 0.782: 0.212: 1: 0.986,
End face of the plate Eu: Sr: Ca: Al: Si = 0.000: 0.756: 0.210: 1: 0.962
The composition was substantially the same in the range of analysis accuracy. Therefore, it was considered that each element including Eu was distributed uniformly.

The obtained alloy showed a powder X-ray diffraction pattern similar to Sr (Si _0.5 Al _0.5 ) ₂ and was identified as an intermetallic compound called AlB ₂ type alkaline earth silicide.

  5 g of alloy powder obtained by pulverizing this plate-like alloy lump in a nitrogen stream to a weight median diameter of 17.4 μm is filled in a boron nitride tray having an inner diameter of 55 mm, and a hot isostatic press (HIP device) Set inside. After evacuating the inside of the apparatus, the apparatus was heated to 300 ° C., and evacuation was continued at 300 ° C. for 1 hour. Thereafter, filling with 1 MPa of nitrogen, releasing the pressure to 0.1 MPa after cooling, and then filling with nitrogen again to 1 MPa were repeated twice. Before starting the heating, nitrogen was filled up to 50 MPa, the temperature was raised to 1900 ° C. at 600 ° C./hr, and at the same time, the internal pressure was increased to 190 MPa at an average of 45 MPa / hr. Then, while maintaining the internal pressure of the apparatus at 190 MPa, it was heated to 1900 ° C. and kept at this temperature for 1 hour to obtain the target phosphor, and coarsely pulverized.

As a result of powder X-ray diffraction measurement of the obtained phosphor, an orthorhombic crystal phase of the same type as CaAlSiN ₃ was generated.

Example 1
The phosphor obtained in Synthesis Example 1 was placed in 10 times the amount of water by weight and stirred for 10 minutes using a stirrer to be dispersed. After standing for 1 hour, it was confirmed that the phosphor had settled, and the phosphor was separated by filtration.
The washed phosphor was subjected to a water dispersion test, the electrical conductivity of the supernatant was measured, and the results are shown in Table 1.
Further, after the washed phosphor was dried at 120 ° C., the emission characteristics were measured, and the results are shown in Table 1.
In Table 1, the luminance is set to 100 as the luminance of the phosphor obtained in Reference Example 1 described later.

(Example 2)
The phosphor obtained in Synthesis Example 1 was placed in 10 times the amount of water by weight and stirred for 10 minutes using a stirrer to be dispersed. After standing for 1 hour, it was confirmed that the phosphor had settled, and the phosphor was separated by filtration. This operation was repeated 17 times.
The washed phosphor was subjected to a water dispersion test, the electrical conductivity of the supernatant was measured, and the results are shown in Table 1.
Further, after the washed phosphor was dried at 120 ° C., the emission characteristics were measured, and the results are shown in Table 1.

(Example 3)
The phosphor obtained in Synthesis Example 1 was placed in a 5-fold amount of 0.5 mol / l hydrochloric acid aqueous solution by weight and stirred for 10 minutes using a stirrer to be dispersed. After standing for 1 hour, it was confirmed that the phosphor had settled, and the phosphor was separated by filtration. This operation was repeated 6 times.
The washed phosphor was subjected to a water dispersion test, the electrical conductivity of the supernatant was measured, and the results are shown in Table 1.
Further, after the washed phosphor was dried at 120 ° C., emission characteristics were measured, emission spectra were shown in FIG. 4, and emission characteristics data were shown in Tables 1 and 2.
In Table 2, the relative peak intensity is shown with the relative peak intensity of Reference Example 1 described later as 100.
Further, FIG. 5 shows a powder X-ray diffraction pattern of the phosphor after washing. From FIG. 5, the peak intensity ratio I of 2θ = 33.2 ° ± 0.2 ° with respect to the strongest peak (I _max ) where 2θ is in the range of 35.5 ° to 37 ° is 1.9%. I understood.

(Comparative Example 1)
The phosphor obtained in Synthesis Example 1 was subjected to a water dispersion test as it was without washing, and the electrical conductivity of the supernatant was measured. The results are shown in Table 1.
The light emission characteristics were measured, and the results are shown in Tables 1 and 2.
Further, the powder X-ray diffraction pattern of this phosphor is shown in FIG. FIG. 6 shows that the peak intensity ratio I of 2θ = 33.2 ° ± 0.2 ° with respect to the strongest peak in the range of 2θ of 35.5 ° to 37 ° is 4.6%.

(Synthesis Example 2)
The phosphors used in Example 4 and Comparative Example 2 were prepared in the same manner as in Synthesis Example 1 except that they were calcined at 1030 ° C. for 8 hours in a normal pressure nitrogen stream before firing in the HIP apparatus. Synthesized.

Example 4
The phosphor obtained in Synthesis Example 2 was put into 10 times the amount of water by weight and stirred for 10 minutes using a stirrer to be dispersed. After standing for 1 hour, it was confirmed that the phosphor had settled, and the phosphor was separated by filtration. The obtained phosphor was pulverized with a ball mill and classified to make the weight median diameter D ₅₀ 9 μm. The obtained phosphor was put into a 0.5 mol / l hydrochloric acid aqueous solution having a weight ratio of 5 times, and stirred and dispersed for 10 minutes using a stirrer. After standing for 1 hour, the phosphor was separated by filtration, and the operation of dispersing in 10 times the amount of water and filtering was repeated 6 times. Since the weight median diameter D ₅₀ of the obtained phosphor was 9 μm, the weight median diameter D ₅₀ was not changed by the above-described washing operation.
The washed phosphor was subjected to a water dispersion test, the electrical conductivity of the supernatant was measured, and the results are shown in Table 1. The light emission characteristics were measured, and the results are shown in Table 1.

(Comparative Example 2)
Without washing the phosphor obtained in Synthesis Example 2, a water dispersion test was conducted as it was, and the electrical conductivity of the supernatant was measured. The results are shown in Table 1. The light emission characteristics were measured, and the results are shown in Table 1.

(Reference Example 1)
Eu ₂ O ₃ , Ca ₃ N ₂ , AlN, and Si ₃ N ₄ are placed in an argon atmosphere so that the metal element composition ratio is Eu: Ca: Al: Si = 0.008: 0.992: 1: 1. And weighed using a mixer. This mixed powder was filled into a boron nitride crucible and set in an atmosphere heating furnace. After evacuating the inside of the apparatus to 1 × 10 ⁻² Pa, evacuation was stopped, filling the apparatus with nitrogen up to 0.1 MPa, heating to 1600 ° C. and holding for 5 hours to obtain the target phosphor. It was.
With respect to this phosphor, when the light emission characteristic by excitation at 465 nm was measured with a fluorescence altitude spectrometer, the emission wavelength was 648 nm.

As is clear from these results, the phosphor cleaning operation improves the luminance of the phosphor as the electrical conductivity of the supernatant liquid in the water dispersion test decreases.
Further, when the powder X-ray diffraction patterns of Example 3 and Comparative Example 1 are compared, it can be seen that in Example 3, the crystallinity is improved, and the portion with poor crystallinity is removed by washing.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Frame 2A Recessed part of frame 3 Blue LED (first light emitter)
4 Phosphor-containing part (second light emitter)
DESCRIPTION OF SYMBOLS 5 Silver paste 6 Wire 7 Mold part 8 Surface emitting illuminating device 9 Diffusion plate 10 Holding case 11 Second light emitter 12 First light emitter 13 Substrate

Claims (8)

Nitride phosphor represented by the following general formula [2], which is the strongest in a powder X-ray diffraction pattern using Cu-Kα rays (1.54184Å) in the range of 2θ of 35.5 ° to 37 ° peak to the height _{I max,} the intensity ratio of the height _{I p} of 2 [Theta] = 33.2 ° ± 0.2 ° peak when the _{I = (I p × 100)} / I max, I is 3 or less There is provided a nitride phosphor.
M ^{1 ′} _{a ′} Sr _{b ′} Ca _{c ′} Al _{e ′} Sif _′ N _{g ′} [2]
(However, a ′, b ′, c ′, e ′, f ′, and g ′ are values in the following ranges, respectively.
0.00001 ≦ a ′ ≦ 0.15
0.6 ≦ b ′ ≦ 0.99999
0 ≦ c ′ <1
a ′ + b ′ + c ′ = 1
0.8 ≦ e ′ ≦ 1.2
0.8 ≦ f ′ ≦ 1.2
2.5 ≦ g ′ ≦ 3.5
M ^{1 ′} represents Eu and / or Ce. ) The nitride phosphor according to claim 1, wherein M ^{1 '} is Eu.   3. The nitride phosphor according to claim 1, wherein 0.7 ≦ b ′ ≦ 0.99999.   The nitride phosphor according to any one of claims 1 to 3, comprising 5% by weight or less of oxygen.   A phosphor-containing composition comprising the phosphor according to any one of claims 1 to 4 and a liquid medium.   5. A light emitting device having an excitation light source and a phosphor that converts at least part of light from the excitation light source, wherein the phosphor is the phosphor according to claim 1. A light emitting device characterized.   An image display device comprising the light emitting device according to claim 6.   An illumination device comprising the light-emitting device according to claim 6.

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