JP2007009141A - Blue light-emitting phosphor and its manufacturing method, light-emitting apparatus, illumination apparatus, back light for display, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient blue phosphor for displays and illumination that highly efficiently emits light in combination with a light source emitting light in the near ultraviolet region, and a light-emitting apparatus using the phosphor. <P>SOLUTION: The blue light-emitting phosphor comprises a europium-activated alkaline earth metal silicate (Ba<SB>a</SB>Ca<SB>b</SB>Sr<SB>c</SB>Mg<SB>d</SB>Eu<SB>x</SB>)SiO<SB>4</SB>, where the coefficient a, b, c, d and x satisfy a+b+c+d+x=2, 0<a<2, 0<b<2, 0≤c<0.5, 0≤d<0.5, and 0<x≤0.5. The manufacturing method of the blue light-emitting phosphor comprises baking a mixture of raw material compounds in the coexistence of carbon. The light-emitting apparatus comprises a first illuminant emitting light having a wavelength of 420 nm or shorter and a second illuminant emitting visible light by irradiation with light from the first illuminant, where the blue light-emitting phosphor is used as the second illuminant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a blue light-emitting phosphor that absorbs light in the ultraviolet light or visible light region and emits long-wavelength visible light, in which the base compound contains an activating element, and a method for producing the same.
The present invention also uses this blue light-emitting phosphor as the second light emitter and combines it with the first light emitter that emits light from the ultraviolet light to the visible light region with a power source, so that it has high intensity regardless of the use environment. The present invention relates to a light-emitting device capable of generating the light emission, a lighting device using the light-emitting device as a light source, a display backlight, and a display.
In the present invention, the blue phosphor refers to the chromaticity coordinates (x, x, x, y, and blue) of JISZ8110-1995 "Color display method-color name of light source color", particularly preferably in the blue range. This refers to a phosphor exhibiting y) emission.

  Excitation of phosphors of three colors of blue, green, and red with ultraviolet light generated by mercury discharge to generate white light is a technology realized in a fluorescent lamp. In recent years, blue light-emitting GaN-based semiconductor light-emitting elements with high luminous efficiency have been developed. The blue light is used to excite a phosphor that emits yellow light, and white light is emitted using the complementary color relationship between blue and yellow. A method of obtaining has been disclosed. However, it has been pointed out that in this method, there is no red component in white light and color rendering is inferior. For this reason, a method has been proposed in which phosphors of three colors, blue, green, and red, are excited by a semiconductor light emitting element that emits near ultraviolet light based on the same principle as a fluorescent lamp. Although this method is still inferior in efficiency and color rendering as compared with a fluorescent lamp, if the semiconductor light emitting device and the phosphor are improved, the performance of the fluorescent lamp can be surpassed.

  Various phosphors used in this method have been proposed. Among these, alkaline earth metal silicate phosphors are considered promising.

For example, Non-Patent Document 1 includes a Me (Me = Ca, Sr, Ba) ₃ MgSi ₂ O ₈ : Eu ²⁺ phosphor, which exhibits blue light emission, from near ultraviolet to around 460 nm. It is shown that it can be excited by blue light, and describes that it belongs to the same orthorhombic system as the natural mineral merwinite. Further, Patent Document 1 discloses a compound represented by the following chemical formula [1] (where a1, b1, and x are in the range of 0 ≦ a1 ≦ 0.3, 0 ≦ b1 ≦ 0.8, and 0 <x <1, respectively. Is the number of
_{(Sr 1-a1-b1-} x Ba a1 Ca b1 Eu x) 2 SiO 4 [1]
FIG. 42 in Patent Document 1 describes that phosphors having a composition satisfying the formula [1] are orthorhombic crystals and monoclinic crystals, and light emission is yellow light emission in the vicinity of a wavelength of 535 nm to 580 nm. Yes.

In Patent Document 2, silicate alkaline earth activated with Eu ²⁺ metal salt phosphor _{A 2 DSi 2 O 7: Eu} 2+ ( wherein, A is Ba, singly of Ca and Sr And D includes one or more of Mg and Zn), and when A and D are Sr and Mg, the wavelength is 470 nm, when Sr and Zn, the wavelength is 470 nm, and when Sr / Ba and Mg, the wavelength is 440 nm. It is disclosed that blue light emission can be seen. However, as can be seen from the description in Patent Document 2, the emission wavelength of Eu ²⁺ is greatly influenced by the host crystal structure such as the composition, crystal structure, and activator concentration, so that a high-efficiency blue phosphor can be stabilized. There were various problems to produce.

Further, Patent Document 3 discloses an alkaline earth metal silicate phosphor activated by Eu ²⁺ represented by the following general formula, and discloses that light emission from blue to green is observed.
_{2 (Ba 1-XY Eu X} M Y) O · nMgO · SiO 2
(However, M has at least one selected from Be, Ca, Sr, and Zn.
X is 0.0001 ≦ X ≦ 0.3
Y is 0 <Y ≦ 0.6
n is 0 ≦ n ≦ 3.0. )

Furthermore, Patent Document 4 discloses that an alkaline earth metal silicate phosphor activated with Eu ²⁺ represented by the following general formula emits blue light.
_{(Ae) ad (Be) Si} b O c: Eu d
(However, Ae is at least one selected from Sr, Ca and Ba, Be is at least one selected from Mg or Zn, and a, b and c are a = 1, b = 1, c = 4 or a = 1, b = 2, c = 6 or a = 2, b = 2, c = 7 or a = 3, b = 2, c = 8, d is 0.01 ≦ d ≦ 0.1 is there)
WO2003 / 021691 Special table 2004-501512 gazette JP 2004-161981 A JP 2004-176010 A Phosphor Handbook, Phosphor Research Society, CRC Press p414〜415 (1998)

However, the blue phosphors disclosed in the above-mentioned known literatures still have insufficient luminous efficiency, and the emission wavelength of Eu ²⁺ has a great influence on the host crystal structure such as composition, crystal structure, and activator concentration. In order to stably produce a high-efficiency blue light emitter, there are various problems. Therefore, in order to provide a display and illumination that emit light with high efficiency in combination with a light source in the near ultraviolet region, It is desired to obtain a phosphor that emits blue light with higher efficiency.

  In addition, as a blue light emitting phosphor, it is of course important that the blue light emission efficiency is high, but there is a degree of freedom in selecting an appropriate emission spectrum shape according to the purpose of the light emitting device to be used. desirable. For example, in applications in which color rendering is more important than luminous efficiency, it is advantageous that the half-value width of the emission spectrum is wide.

In view of this point, an object of the present invention is to provide a blue phosphor having a wide half-value width of an emission spectrum and a method for producing the same.
The present invention also provides a light emitting device having high color rendering properties using such a blue light emitting phosphor, an illumination device using the light emitting device as a light source, a backlight for display, and a display.

Blue-emitting phosphor of the present invention (claim 1) the composition _{formula: (Ba a Ca b Sr c} Mg d Eu x) consisting of europium activated alkaline earth metal silicate represented by SiO ₄ blue-emitting phosphor In the composition formula, the coefficients a, b, c, d and x are a + b + c + d + x = 2
0 <a <2
0 <b <2
0 ≦ c <0.5
0 ≦ d <0.5
0 <x ≦ 0.5
It is characterized by satisfying.

The blue light-emitting phosphor according to claim 2 is a specific crystal satisfying the following conditions (1) and (2) in the phosphor according to claim 1 in an X-ray diffraction measurement using a CuKα X-ray source. It is characterized by including a phase.
(1) A diffraction peak is observed in a diffraction angle (2θ) range of 21.30 to 22.50 ° (R ₀ ). This diffraction peak is defined as a reference diffraction peak (P ₀ ), and a Bragg angle (θ ₀ ) of P ₀ is used. ) When the following ranges of the five diffraction angles are R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ , at least one diffraction peak exists in each of these ranges.
(2) P ₀ is a diffraction peak height ratio of 20% with respect to the strongest diffraction peak among a total of six diffraction peaks of the reference diffraction peak P ₀ and the peaks existing in the range of R _{1 to} R _5. The other diffraction peaks have the above intensity, and the diffraction peak height ratio is 9% or more.
However, in any of the above (1) and (2), when two or more diffraction peaks exist in one angle range, a peak having a high intensity is adopted.
R ₁ : 2 × arcsin {sin (θ ₀ ) / (0.720 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.720 × 0.985)}
R ₂ : 2 × arcsin {sin (θ ₀ ) / (0.698 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.698 × 0.985)}
R ₃ : 2 × arcsin {sin (θ ₀ ) / (0.592 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.592 × 0.985)}
R ₄ : 2 × arcsin {sin (θ ₀ ) / (0.572 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.572 × 0.985)}
R ₅ : 2 × arcsin {sin (θ ₀ ) / (0.500 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.500 × 0.985)}

  The blue phosphor according to claim 3 is characterized in that, in the phosphor according to claim 1 or 2, the coefficients a and b satisfy 1 ≦ (a / b) ≦ 10.

  The method for producing a blue-emitting phosphor according to the present invention (invention 4) is the method for producing a phosphor according to any one of claims 1 to 3, wherein element source compounds of Ba, Ca, Eu and Si are used. And a mixture of Sr and / or Mg element source compounds used as necessary, is characterized by firing in the presence of carbon.

  The light-emitting device of the present invention (Claim 5) includes a first light-emitting body that generates light having a wavelength of 420 nm or less, and a second light-emitting body that generates visible light when irradiated with light from the first light-emitting body. A light emitting device comprising: the second light emitter includes the phosphor according to any one of claims 1 to 3 or the phosphor obtained by the manufacturing method according to claim 4. To do.

  The illumination device of the present invention (Claim 6) is characterized by using the light-emitting device according to Claim 5.

  The display backlight according to the present invention (invention 7) is characterized in that the light emitting device according to claim 5 is used.

  The display of the present invention (invention 8) is characterized by using the light emitting device according to claim 5.

  According to the present invention, a high-luminance and high-efficiency blue phosphor having a broad half-value width of an emission spectrum is obtained. Using this blue-emitting phosphor, a light-emitting device with high color rendering properties and this light-emitting device are used. And high performance lighting devices, display backlights and displays are provided.

  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.

[1] blue-emitting phosphor of the blue-emitting phosphor present invention is a blue-emitting phosphor consisting of europium-activated alkaline earth metal silicate _{(Ba a Ca b Sr c Mg} d Eu x) SiO 4, coefficients a, b, c, d and x are a + b + c + d + x = 2
0 <a <2
0 <b <2
0 ≦ c <0.5
0 ≦ d <0.5
0 <x ≦ 0.5
And preferably has a specific crystal phase described later.

  That is, in the present invention, it is made of Eu-activated alkaline earth silicate containing at least one element selected from the group consisting of Ba, Sr, Ca, and Mg, and preferably emits light by having a specific crystal phase. A high-intensity blue-emitting phosphor is realized.

[Difference between the conventional phosphor and the blue light-emitting phosphor of the present invention]
Prior to describing the blue light-emitting phosphor of the present invention in detail, first, the difference between the blue light-emitting phosphor of the present invention and the above-described conventional phosphor will be described.

The Me (Me = Ca, Sr, Ba) ₃ MgSi ₂ O ₈ : Eu ²⁺ phosphor described in Non-Patent Document 1 activates Eu to a natural mineral merwinite itself and a base crystal substituted with Ca, Ba, or Sr. Although only a composition that becomes (Me _1.5-x Eu _x Mg _0.5 ) SiO ₄ is disclosed using the same notation method as in the present invention, the present invention does not include this composition.

  Japanese Patent Application Laid-Open No. H10-260707 excites a phosphor that emits yellow light by blue light from a GaN-based semiconductor light-emitting element, and uses yellow-based light emission for a method of obtaining white light by utilizing the complementary color relationship between blue and yellow of the semiconductor light-emitting element. This phosphor is different from the blue light-emitting phosphor excited by near-ultraviolet light of the present invention.

The phosphor described in Patent Document 2 has a matrix crystal composition of A ₂ DSi ₂ O ₇ (wherein A includes one or more of Ba, Ca and Sr, and D includes one or more of Mg and Zn). The present invention is basically M ₂ SiO ₄ type and has a different composition.

The composition represented by Patent Literature _{3 2 (Ba 1-XY Eu} X M Y) O · nMgO · SiO 2 ( where, M is Be, Ca, Sr, .X having at least one or more selected from Zn is 0.0001 ≦ X ≦ 0.3, Y is 0 <Y ≦ 0.6, and n is 0 ≦ n ≦ 3.0) according to the same notation as the present invention (Ba _{2 -2X-2Y} Eu _2X M _2Y Mg _n ) SiO _{4 + n}
Thus, except for the case of n = 0, the composition is different from that of the present invention. In the case of n = 0, in the example of Patent Document 3, the chromaticity coordinates (x, y) are in the range of x = 0.156 to 0.366, y = 0.499 to 0.548, and exhibit green light emission. It is. On the other hand, the blue light emitting phosphor of the present invention is a blue light emitting phosphor having an emission color in the range of x = 0.160 to 0.187 and y = 0.172 to 0.263. That is, different emission colors mean different phosphors. The fact that such a clear difference occurs is considered to be due to the fact that the special reducing atmosphere at the time of firing in the present invention has brought the reduced state of Eu ions into a state of emitting blue light.

Furthermore, Patent Document _{4, (Ae) ad (Be} ) Si b O c: Eu d ( provided that at least one Ae is at least one selected from Sr, Ca and Ba, Be is selected from Mg or Zn Where a = 1, b = 1, c = 4 or a = 1, b = 2, c = 6 or a = 2, b = 2, c = 7 or a = 3, b = 2, c = 8, and d is 0.01 ≦ d ≦ 0.1). A blue light-emitting phosphor mainly used for a plasma display panel is disclosed. Among them, when a = 1, b = 1, and c = 4, the general formula is the same as that of the present invention, but in Patent Document 4, at least one selected from Sr, Ca, and Ba represented by Ae In the present invention, the number of moles of Mg is less than the number of moles of at least one alkaline earth metal ion selected from Sr, Ca and Ba. It has been found that extremely high luminous efficiency can be obtained by near-ultraviolet light excitation.

  Further, in the present invention, the crystal phases of the blue light emitting phosphor of the present invention are specified by X-ray diffraction and clearly differentiated from the phosphors of all known documents exemplified here.

[composition]
In the blue-emitting phosphor of the composition formula of the europium-activated alkaline earth metal silicate _{(Ba a Ca b Sr c Mg} d Eu x) SiO 4 of the present invention, the alkaline earth metals Ba, Ca, Sr, Mg and activated For the total number of moles of the element Eu, a + b + c + d + x = 2 holds. However, since the value of a + b + c + d + x may deviate by about ± 1% depending on the purity of the element source compound, experimental error, etc., the case of deviation of about ± 1% is also included in the scope of the present invention.
The ratio of Ba to Ca (molar ratio a / b) is usually 1 ≦ (a / b) ≦ 10, but preferably 1.5 ≦ (a / b) ≦ from the viewpoint of color rendering properties and emission peak intensity. 8, more preferably 2 ≦ (a / b) ≦ 4.

  From the viewpoint of blue emission intensity, the ratio of the total of Ba and Ca in the alkaline earth metal is preferably 70 mol% or more, more preferably 90 mol% or more, and further preferably 100 mol%. preferable.

  Si can be partially substituted by Ge or other tetravalent elements. Examples of tetravalent elements other than Si and Ge include Zn, Ti, and Hf. These may be included as long as the performance such as blue emission intensity is not impaired. However, it is preferable that Si and Ge are included in total in a total including Si and other tetravalent elements. From the viewpoint of the light emission intensity, etc., it is preferable that Si is contained in an amount of 80 mol% or more, and it is more preferable that all be made of Si.

  The Sr molar ratio c is 0 ≦ c <0.5, but preferably c ≦ 0.2 from the viewpoint of color rendering.

  The Mg molar ratio d is 0 ≦ d <0.5, but d ≦ 0.2 is preferable from the viewpoint of color rendering.

For Eu molar ratio x, Eu ²⁺ can be represented because replacing an alkaline earth metal element and _{(Ba a Ca b Sr c Mg} d Eu x) SiO 4, wherein, x is 0 <x ≦ Although the number satisfies 0.5, if the molar ratio x of the emission center ion Eu ²⁺ is too small, the emission intensity tends to decrease, whereas if it is too large, the emission peak shifts to the long wave side and blue light emission occurs. No longer shows. The lower limit of the Eu molar ratio x is preferably 0.001 ≦ x, more preferably 0.005 ≦ x, and the upper limit is more preferably x ≦ 0.1.

[Crystal phase]
The present inventors have found that a phosphor having a specific crystal structure in addition to the above composition range has particularly high emission intensity.

The crystal structure is generally defined using a crystal system, a space group, etc., but the crystal phase in the present invention is a crystal system, a space due to a crystal structure distortion (subtle structural change) accompanying a change in composition. Since the change of the group occurs, it is not possible to define a unique structure.
Therefore, an X-ray diffraction pattern necessary for specifying a crystal phase contributing to light emission is disclosed.
Usually, in order to specify that the crystal structures of two compounds are the same based on the X-ray diffraction pattern, the angles (2θ) of about six diffraction peaks including the strongest diffraction peak based on the crystal structure should coincide. . However, when the constituent element ratios are different as in the compound of the present invention, the angle of the diffraction peak shifts even if the crystal structure is the same. Therefore, the specific angle of the diffraction peak cannot be defined as a numerical value.
Therefore, the inventors focused on the diffraction peak plane distance calculated using the Bragg equation, and specified the diffraction peak angle range by the following display method.
Bragg's equation d = λ / {2 × sin (θ)} (Equation 1)
θ = arcsin {λ / (2 × d)} (Expression 2) * Expression 2 is a modification of Expression 1, where
d: Surface spacing (Å)
θ: Bragg angle (°)
λ: CuKα X-ray wavelength = 1.54184
It is.

If the interplanar spacing range of the reference diffraction peak is defined as 4.17 ° to 3.95 °, the range (R ₀ ) of the diffraction angle (2θ) is 21.30 ° to 22.50 ° from Equation 2.

From the observed angle (θ ₀ ) of the reference diffraction peak, the interplanar spacing (d ₀ ) of the reference diffraction peak P ₀ is expressed by Equation 3 below from Equation 1.
d ₀ = λ / {2 × sin (θ ₀ )} (Equation 3)

Five peaks other than the reference diffraction peak are designated as P ₁ , P ₂ , P ₃ , P ₄ , and P ₅ from the low angle side, and the angle ranges where each peak appears are R ₁ , R ₂ , R ₃ , R in order. ₄ and R ₅ .

The angle range R _{1 in which} P ₁ appears is determined as follows.
When the diffraction plane has a plane spacing of 0.720 times the plane spacing (d ₀ ) derived from the reference diffraction peak, and the deviation of the plane spacing due to structural distortion is 1.5%, the starting angle of the angle range R ₁ (R _1s ) and end angle (R _1e ) are derived from Equation 1 as follows.
R _1s : 2 × arcsin {λ / (2 × d ₀ × 0.720 × 1.015)}
R _1e : 2 × arcsin {λ / (2 × d ₀ × 0.720 × 0.985)}
Substituting Equation 3 for each,
R _1s : 2 × arcsin {sin (θ ₀ ) / (0.720 × 1.015)}
R _1e : 2 × arcsin {sin (θ ₀ ) / (0.720 × 0.985)}
It becomes.

Similarly, the angle range in which P ₂ , P ₃ , P ₄ , and P ₅ appear is 0.698 times, 0.592 times, 0.572 times, and 0.500 times with respect to the plane distance derived from the reference diffraction peak. defined, the deviation of the interplanar spacing accompanying distortion of the structure is 1.5% uniformly, the start angle of the angle range R ₂ (R _2s) and ending angle (R _2e), the start angle of the angle range R ₃ (R _3s) and ending angle (R _3e), the start angle of the angle range R ₄ (R _4s) and ending angle (R _4e), start angle (R _5s) and end angle of the angle range R ₅ (R _5e) is represented by the following It becomes as follows.
R _2s : 2 × arcsin {sin (θ ₀ ) / (0.698 × 1.015)}
R _2e : 2 × arcsin {sin (θ ₀ ) / (0.698 × 0.985)}
R _3s : 2 × arcsin {sin (θ ₀ ) / (0.592 × 1.015)}
R _3e : 2 × arcsin {sin (θ ₀ ) / (0.592 × 0.985)}
R _4s : 2 × arcsin {sin (θ ₀ ) / (0.572 × 1.015)}
R _4e : 2 × arcsin {sin (θ ₀ ) / (0.572 × 0.985)}
R _5s : 2 × arcsin {sin (θ ₀ ) / (0.500 × 1.015)}
R _5e : 2 × arcsin {sin (θ ₀ ) / (0.500 × 0.985)}

That is, by confirming that each peak from the reference peaks P ₀ to P ₅ appears in the following angle range in the obtained X-ray diffraction measurement result, the specific crystal structure according to the present invention exists. Can be confirmed.
R ₁ : 2 × arcsin {sin (θ ₀ ) / (0.720 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.720 × 0.985)}
R ₂ : 2 × arcsin {sin (θ ₀ ) / (0.698 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.698 × 0.985)}
R ₃ : 2 × arcsin {sin (θ ₀ ) / (0.592 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.592 × 0.985)}
R ₄ : 2 × arcsin {sin (θ ₀ ) / (0.572 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.572 × 0.985)}
R ₅ : 2 × arcsin {sin (θ ₀ ) / (0.500 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.500 × 0.985)}
This crystal phase is a crystal phase different from merwinite.

More preferably, the angular ranges R _{1 to} R ₅ are as follows, assuming that the deviation of the interplanar spacing due to the strain of the structure is uniformly 1.0%.
R ₁ : 2 × arcsin {sin (θ ₀ ) / (0.720 × 1.010)}
˜2 × arcsin {sin (θ ₀ ) / (0.720 × 0.990)}
R ₂ : 2 × arcsin {sin (θ ₀ ) / (0.698 × 1.010)}
˜2 × arcsin {sin (θ ₀ ) / (0.698 × 0.990)}
R ₃ : 2 × arcsin {sin (θ ₀ ) / (0.592 × 1.010)}
˜2 × arcsin {sin (θ ₀ ) / (0.592 × 0.990)}
R ₄ : 2 × arcsin {sin (θ ₀ ) / (0.572 × 1.010)}
˜2 × arcsin {sin (θ ₀ ) / (0.572 × 0.990)}
R ₅ : 2 × arcsin {sin (θ ₀ ) / (0.500 × 1.010)}
˜2 × arcsin {sin (θ ₀ ) / (0.500 × 0.990)}

The crystal phase of the blue light-emitting phosphor of the present invention has at least one diffraction peak in each of the angle ranges of R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ , and P ₀ and R ₁ to P ₀ has a diffraction peak height ratio of 20% or more with respect to the strongest diffraction peak out of a total of six diffraction peaks with each peak present in R ₅ . Those having a P ₀ diffraction peak height ratio of less than 20% cannot be said to be a specific crystal structure according to the present invention. This height ratio is preferably 20% or more and 100% or less. The other diffraction peaks have a diffraction peak height ratio of 9% or more. Those having a height ratio of less than 9% cannot be said to be a specific crystal structure according to the present invention. Preferably, the height ratio is 9% or more and 100% or less.
However, when there are two or more diffraction peaks in one angle range, a peak having a high intensity is adopted.

[2] Method for producing blue-emitting phosphor The blue-emitting phosphor of the present invention has an alkaline earth metal source, an Si source, and an element source of Eu as an activator so as to have the composition as described above. It can be produced by heating and firing a mixture obtained by mixing the compounds by the following mixing method (A) or (B) (hereinafter referred to as “raw material mixture”).
(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., pulverization using mortar and pestle, etc., and mixer such as ribbon blender, V-type blender, Henschel mixer, or mortar and pestle Dry mixing method combined with mixing.
(B) A wet mixing method in which water or the like is added and mixed in a slurry state or a solution state by a pulverizer, a mortar and pestle, or an evaporating dish and a stirring bar, and then dried by spray drying, heat drying, natural drying or the like.

  As the alkaline earth metal source, silicon source, and Eu source compound of the activating element used for preparing the raw material mixture, the respective oxides, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates Among them, the halide is selected in consideration of the reactivity to the composite oxide and the non-generation of NOx, SOx, etc. during firing.

Specific examples of the Ba, Ca, Sr, and Mg source compounds mentioned as alkaline earth metals include BaO, Ba (OH) ₂ .8H ₂ O, BaCO ₃ , Ba. (NO ₃ ) ₂ , BaSO ₄ , Ba (OCO) ₂ .2H ₂ O, Ba (OCOCH ₃ ) ₂ , BaCl _2, etc., and Ca source compounds include CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, Ca (OCO) ₂ .H ₂ O, Ca (OCOCH ₃ ) ₂ .H ₂ O, CaCl _{2 and the} like are also used as Sr source compounds. Are SrO, Sr (OH) ₂ .8H ₂ O, SrCO ₃ , Sr (NO ₃ ) ₂ , SrSO ₄ , Sr (OCO) ₂ .H ₂ O, Sr (OCOCH ₃ ) ₂ .0.5H ₂ O, Examples thereof include SrCl ₂ . The Mg source _{compound, MgO, Mg (OH) 2} , MgCO 3, Mg (OH) 2 · 3MgCO 3 · 3H 2 O, Mg (NO 3) 2 · 6H 2 O, MgSO 4, Mg (OCO) 2 · 2H ₂ O, Mg (OCOCH ₃ ) ₂ .4H ₂ O, MgCl _{2 and the} like.

Specific examples of compounds that are raw materials for Si and Ge include SiO ₂ , H ₄ SiO ₄ , Si (OCOCH ₃ ) _{4 and the} like as the Si source compound, and GeO as the Ge source compound. ₂ , Ge (OH) ₄ , Ge (OCOCH ₃ ) ₄ , GeCl _{4 and the} like.

Further, with respect to Eu mentioned as an activator element, specific examples of the element source compound include Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (OCO) ₆ , EuCl ₂ , EuCl. ₃ , Eu (NO ₃ ) ₃ · 6H ₂ O, and the like.

  One of these raw material compounds may be used alone, or two or more thereof may be mixed and used.

As a firing atmosphere of the raw material mixture, an atmosphere necessary for obtaining an ion state (valence) in which the activating element contributes to light emission is selected. In the present invention, Eu as the luminescent center element that causes blue light emission needs to be a divalent ion. However, as the Eu source compound, a raw material in which Eu is trivalent such as Eu ₂ O ₃ is usually used. Therefore, in order to obtain a phosphor that emits blue light of Eu ²⁺ , it is necessary to reduce trivalent Eu to divalent Eu during firing. For this reason, conventionally, firing is generally performed in some kind of reducing atmosphere such as carbon monoxide, nitrogen / hydrogen, or hydrogen.

On the other hand, the present inventors specialize that carbon (solid carbon) coexists when the raw material mixture is calcined and trivalent Eu ions are reduced to divalent ions and simultaneously introduced into the host crystal. It has been found that when calcination is performed under various reducing conditions, a blue-emitting phosphor having a wavelength shorter than 490 nm and high luminance and simultaneously having a broad emission spectrum width can be realized.
Further, it has been found that the crystal structure of the phosphor fired under these conditions brings about the X-ray diffraction result of claim 2 and is a special structure.

  Here, various types of materials can be used as the solid carbon. For example, 1 type (s) or 2 or more types, such as carbon black, activated carbon, pitch, coke, graphite, can be used.

  Here, the firing in the presence of carbon is sufficient if carbon is present in the same firing container, and it is not necessary to mix the raw material mixture and carbon for firing. In general, when carbon is mixed in a phosphor product, the black carbon absorbs light and the efficiency is lowered. As an example of coexistence, there is a method of using a graphite crucible as a firing container. In addition, when using a crucible other than graphite, for example, an alumina crucible, a method of coexisting graphite beads, granules, blocks and the like as follows can be mentioned. In other words, in the same crucible, use a container filled with carbon in a container without a lid, and place this container on the top of the filled raw material, embed it in the raw material powder, or conversely without another lid Examples thereof include a method of filling a container with a raw material mixture and arranging carbon around the container. In any case, it is important to devise so that the coexisting carbon and the raw material mixture are present in the same atmosphere and that carbon is not mixed into the phosphor from which the carbon is obtained.

The firing is performed in a heat-resistant container such as a crucible or a tray using a material having low reactivity with the raw material mixture, usually at a temperature of 750 to 1400 ° C., preferably 900 to 1300 ° C., in the atmosphere, carbon monoxide, carbon dioxide. It is performed by heating for 10 minutes to 24 hours under the condition of coexisting with carbon as described above, alone or in a mixed atmosphere of a gas such as nitrogen, hydrogen, and argon.
After such heat treatment, washing, drying, classification, etc. are performed as necessary.

  In addition, when manufacturing a light-emitting device by the below-mentioned method using the obtained fluorescent substance, it is preferable to disperse | distribute in resin after performing well-known surface treatment, for example, a calcium phosphate process.

[3] Light-emitting device The light-emitting device of the present invention includes a first light-emitting body that generates light having a wavelength of 420 nm or less, and a second light-emitting body that generates visible light by irradiation of light from the first light-emitting body. The blue light-emitting phosphor of the present invention described above is used as the second light emitter.

In the present invention, the first light emitter that irradiates the second phosphor with light generates short-wave light having a wavelength of 420 nm or less. Specific examples of the first light emitter include a light emitting diode (LED) or a laser diode (LD). A laser diode is more preferable because it consumes less power. Of these, GaN LEDs and LDs using GaN compound semiconductors are preferred. This is because GaN-based LEDs and LDs have much higher light output and external quantum efficiency than SiC-based LEDs that emit light in this region, and are extremely low power when combined with the blue light-emitting phosphor of the present invention. This is because very bright light emission can be obtained. For example, for a current load of 20 mA, the GaN system usually has a light emission intensity 100 times or more that of the SiC system. 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 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 GaN-based LDs, the multiple quantum of the In _X Ga _Y N layer and the GaN layer is preferred. 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 constituent elements. The light-emitting layer is made of n-type and p-type Al _x Ga _y N layers, GaN layers, or In _x. Those having a heterostructure sandwiched between Ga _Y N layers and the like have high luminous efficiency, and those having a heterostructure having a quantum well structure have higher luminous efficiency and are more preferable.

In the light emitting device of the present invention, in addition to the method of using the phosphor of the present invention alone, a light emitting device that emits a desired color can be configured by using in combination with a phosphor having other light emission characteristics. As an example of this, an ultraviolet LED light emitting device of 330 to 420 nm, a red phosphor excited at this wavelength and having an emission peak at a wavelength of 600 to 660 nm, a green phosphor having an emission peak at a wavelength of 500 to 550 nm, There are phosphor combinations of the invention. The red phosphor used here is a europium-activated rare earth oxychalcogenite-based phosphor represented by (Y, La, Gd, Lu) ₂ O ₂ S: Eu, with europium represented by CaAlSiN ₃ : Eu. Examples thereof include active nitride phosphors, europium represented by Ba ₃ CaSi ₂ O ₈ : Eu, Mn, and manganese-activated alkaline earth metal silicate phosphors. As the green phosphor, europium activated aluminate phosphor represented by BaMgAl ₁₀ O ₁₇ : Eu, Mn, europium activated by (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu Examples include alkaline earth silicon oxynitride phosphors, europium activated alkaline earth metal silicate phosphors represented by Ba ₂ SiO ₄ : Eu. In this configuration, when ultraviolet light emitted from the LED is irradiated onto the phosphor, light of three colors of red, green, and blue is emitted, and a light emitting device that emits white light by mixing these fluorescences is obtained.

  Hereinafter, a light emitting device of the present invention including such a first light emitter and a second light emitter will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a light emitting device of the present invention having a first light emitter (light emitter that generates light having a short wavelength of 420 nm or less) and a second light emitter. FIG. 2 is a schematic cross-sectional view showing an embodiment of a surface-emitting illumination device incorporating the light-emitting device shown in FIG. 1 and 2, 1 is a light emitting device, 2 is a mount lead, 3 is an inner lead, 4 is a first light emitter, 5 is a phosphor-containing resin portion as a second light emitter, and 6 is a conductive wire. , 7 is a mold member, 8 is a surface emitting illumination device, 9 is a diffusion plate, and 10 is a holding case.

  As shown in FIG. 1, the light emitting device 1 has a general shell shape, and a first light emitter (350 to 430 nm) made of a GaN-based light emitting diode or the like is placed in the upper cup of the mount lead 2. The phosphor-containing resin portion formed as a second phosphor by mixing and dispersing the phosphor in a binder such as a silicon resin, an epoxy resin, or an acrylic resin and pouring the phosphor into the cup. It is fixed by being covered with 5. On the other hand, the first light emitter 4 and the mount lead 2, and the first light emitter 4 and the inner lead 3 are electrically connected by a conductive wire 6, respectively, which are entirely covered with a mold member 7 made of epoxy resin or the like, Protected.

  In addition, as shown in FIG. 2, the surface-emitting illumination device 8 incorporating the light-emitting device 1 has a large amount of light emission on the bottom surface of a rectangular holding case 10 whose inner surface is light-opaque such as a white smooth surface. The device 1 is arranged with a power supply and a circuit (not shown) for driving the light emitting device 1 provided outside thereof, and a milky white acrylic plate or the like is provided at a position corresponding to the lid portion of the holding case 10. The diffusion plate 9 is fixed for uniform light emission.

  Then, by driving the surface emitting illumination device 8 and applying a voltage to the first light emitter 4 of the light emitting device 1, light having a wavelength shorter than 420 nm is emitted, and a part of the light emission is converted into the second light emitter. The phosphor in the phosphor-containing resin part 5 absorbs and emits visible light having a longer wavelength (exceeding 420 nm), while color rendering is achieved by color mixing with blue light or the like that is not absorbed by the phosphor. High light emission is obtained, and this light is transmitted through the diffusion plate 9 and emitted upward in the drawing, and illumination light with uniform brightness can be obtained within the surface of the diffusion plate 9 of the holding case 10.

  The phosphor-containing resin portion 5 in the light emitting device 1 has the following effects. That is, the light from the first light emitter and the light from the second light emitter are usually directed in all directions, but when the phosphor powder of the second light emitter is dispersed in the resin, Since part of the light is reflected when it goes out of the resin, the direction of light can be aligned to some extent. Accordingly, since light can be guided to a certain degree in an efficient direction, it is preferable to use a phosphor in which the phosphor powder is dispersed in a resin as the second luminous body. Further, when the phosphor is dispersed in the resin, the total irradiation area of the light from the first light emitter to the second light emitter is increased, so that the light emission intensity from the second light emitter can be increased. It also has the advantage of being able to.

As a resin that can be used for the phosphor-containing resin part, various kinds such as silicon resin, epoxy resin, polyvinyl resin, polyethylene resin, polypropylene resin, and polyester resin can be used alone or in combination of two or more. In view of the good dispersibility of the phosphor powder, silicon resin and epoxy resin are preferable. When the phosphor powder is dispersed in the resin, the weight ratio of the phosphor powder to the total of the phosphor powder and the resin is usually 0.1 to 20% by weight, preferably 0.3 to 15% by weight, More preferably, it is 0.5 to 10% by weight. If there is too much phosphor within this range, the luminous efficiency may decrease due to aggregation of the phosphor powder, and if it is too small, the luminous efficiency may decrease due to light absorption or scattering by the resin. In this resin, a bulking agent may be added in order to prevent color spots (unevenness).
As described above, the phosphor is preferably dispersed in the resin after performing a known surface treatment if necessary.

  In the present invention, it is particularly preferable to use a surface-emitting type illuminant, particularly a surface-emitting GaN-based laser diode, as the first illuminant because the luminous efficiency of the entire light-emitting device is increased. A surface-emitting type illuminant is an illuminant that emits strong light in the surface direction of a film. In a surface-emitting GaN-based laser diode, the crystal growth of a light-emitting layer or the like is controlled, and a reflective layer or the like is successfully performed. By devising, the light emission in the surface direction can be made stronger than the edge direction of the light emitting layer. When the surface emitting type is used, the light emission cross-sectional area per unit light emission amount can be increased compared to the type that emits light from the edge of the light emitting layer. As a result, the phosphor of the second light emitter is irradiated with the light Since the irradiation area can be made very large with the same amount of light and the irradiation efficiency can be improved, stronger light emission can be obtained from the phosphor that is the second light emitter.

  As described above, when a surface-emitting type is used as the first light emitter, the second light emitter is preferably a film. Since the light from the surface-emitting type first light emitter has a sufficiently large cross-sectional area, if the second light emitter is formed into a film shape in the direction of the cross section, irradiation per unit amount of phosphor from the first light emitter Since the cross-sectional area is increased, the intensity of light emitted from the phosphor can be further increased.

  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 means to create a state in which the first light emitter and the second light emitter are in close 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 in which a surface light emitting type is used as the first light emitter and a film-like one is used as the second light emitter. 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 separately formed, and the surfaces may be brought into contact with each other by an adhesive or other means. The second light emitter 11 may be formed (molded) on the light emitting surface of the LD 12. As a result, the LD 12 and the second light emitter 11 can be brought into contact with each other.

A light emitting device of the present invention includes a second light emitter as a wavelength conversion material including the above-described blue light emitting phosphor of the present invention, and a first light emitter that generates light having a short wavelength of 420 nm or less. The blue light-emitting phosphor of the present invention in the light-emitting body 2 absorbs light having a short wavelength of 420 nm or less emitted from the first light-emitting body, has good color rendering properties regardless of the use environment, and has high-intensity visible light. It is a light emitting device capable of generating light. In such a light emitting device, the blue light emitting phosphor of the present invention having the specific crystal phase and composition described above emits blue light when irradiated with light from the first light emitter that generates light having a short wavelength of 420 nm or less. It emits light in a wavelength region of a wavelength shorter than 500 nm, preferably 450 to 490 nm.
Such a light emitting device of the present invention is suitable for a light source such as a backlight source, a light source such as a traffic light, an image display device such as a color liquid crystal display, and a lighting device such as a surface emitting device.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Example 1>
BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , SiO ₂ as raw material compounds are weighed so that the molar ratio of Ba, Ca, Eu, Si is 1.49: 0.5: 0.01: 1, and flux NH ₄ Cl was added and mixed with a ball mill for 1 hour. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. Activated carbon was filled in the gap between the large crucible and the small crucible. The lid is for preventing the activated carbon from being mixed into the small crucible. Since there is a slight gap between the lid and the small crucible body, the carbon coexistence condition is satisfied.
In this state, phosphor Ba _1.49 Ca _0.5 Eu _0.01 SiO ₄ was produced by heating at 1200 ° C. for 4 hours under a nitrogen gas flow containing 4% hydrogen. X-ray diffraction measurement of this phosphor was performed under the following conditions.
Using a Bragg-Brentano type powder X-ray diffractometer comprising a CuKα X-ray source optically adjusted so that the diffraction angle error within the scanning range is Δ2θ = 0.05 ° or less, and the diffraction angle error due to sample eccentricity is Using the 111 peak of standard silicon, powder X-ray diffraction measurement was performed under conditions where an angle reproducibility of Δ2θ = 0.05 ° or less was guaranteed. In addition, the divergence angle of the divergence slit is adjusted so that the X-ray irradiation width does not exceed the width of the sample during measurement, and the diffraction peak position (peak top) and diffraction intensity (height) are measured in the fixed slit mode. The value of was read.
FIG. 4 and Table 1 show the X-ray diffraction measurement results.

  From these results, it was confirmed that the obtained phosphor satisfied the conditions described in claim 2 and contained the specific crystal phase described above.

  FIG. 5 shows an emission spectrum when this phosphor is excited at 400 nm, which is the dominant wavelength in the near ultraviolet region of a GaN-based light emitting diode. Here, in order to remove the influence of the excitation light source on the emission spectrum, light having a wavelength of 420 nm or less is cut.

  In addition, Table 2 shows the emission characteristics of the present phosphor: peak intensity, peak wavelength, half width, and chromaticity coordinates (x, y). The peak intensity is a value with the luminance of Comparative Example 1 described later as 100.

<Example 2>
BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , and SiO ₂ as raw material compounds are weighed so that the molar ratio of Ba, Ca, Eu, and Si is 1.46: 0.49: 0.05: 1, and flux NH ₄ Cl was added and mixed with a ball mill for 1 hour. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. Activated carbon was filled in the gap between the large crucible and the small crucible. In this state, phosphor Ba _1.46 Ca _0.49 Eu _0.05 SiO ₄ was produced by heating at 1300 ° C. for 2 hours under a nitrogen gas flow containing 4% hydrogen.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1.
FIG. 6 shows the result of X-ray diffraction measurement of this phosphor, FIG. 7 shows the emission spectrum, and Table 2 summarizes the characteristics.

<Example 3>
BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , and SiO ₂ as raw material compounds are weighed so that the molar ratio of Ba, Ca, Eu, and Si is 1.46: 0.49: 0.05: 1, and flux NH ₄ Cl was added and mixed with a ball mill for 1 hour. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. Activated carbon was filled in the gap between the large crucible and the small crucible. In this state, phosphor Ba _1.46 Ca _0.49 Eu _0.05 SiO ₄ was produced by heating at 1200 ° C. for 4 hours under a nitrogen gas flow.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
FIG. 7 shows the emission spectrum of this phosphor, and Table 2 summarizes its characteristics.

<Example 4>
BaCO ₃ , CaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , and SiO ₂ are used as raw material compounds, and the molar ratio of Ba, Ca, Mg, Eu, and Si is 1.37: 0.5: 0.1: 0.03: Weighed to 1 and added NH ₄ Cl as flux and mixed for 1 hour in a ball mill. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. Activated carbon was filled in the gap between the large crucible and the small crucible. In this state, phosphor Ba _1.37 Ca _0.5 Mg _0.1 EuSiO ₄ was produced by heating at 1100 ° C. for 4 hours under a nitrogen gas flow containing 4% hydrogen.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
FIG. 7 shows the emission spectrum of this phosphor, and Table 2 summarizes its characteristics.

<Example 5>
BaCO ₃ , CaCO ₃ , SrCO ₃ , Eu ₂ O ₃ , and SiO ₂ are used as raw material compounds, and the molar ratio of Ba, Ca, Sr, Eu, and Si is 1.39: 0.5: 0.1: 0.01: A phosphor Ba _1.39 Ca _0.5 Sr _0.1 Eu _0.01 SiO ₄ was obtained in the same manner as in Example 3 except that the weight was adjusted to 1.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
FIG. 7 shows the emission spectrum of this phosphor, and Table 2 summarizes its characteristics.

<Example 6>
Except that BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ and SiO ₂ were measured as raw material compounds so that the molar ratio of Ba, Ca, Eu and Si was 1.593: 0.4: 0.007: 1. In the same manner as in Example 1, a phosphor Ba _1.593 Ca _0.4 Eu _0.007 SiO ₄ was obtained.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
FIG. 7 shows the emission spectrum of this phosphor, and Table 2 summarizes its characteristics.

<Comparative example 1>
BaCO ₃ , MgCO ₃ , Eu ₂ O ₃ , SiO ₂ as raw material compounds are weighed so that the molar ratio of Ba, Mg, Eu, Si is 1.49: 0.5: 0.01: 1, and flux NH ₄ Cl was added and mixed with a ball mill for 1 hour. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. The gap between the large crucible and the small crucible was not filled with activated carbon. In this state, phosphor Ba _1.49 Mg _0.5 Eu _0.01 SiO ₄ was produced by heating at 1200 ° C. for 4 hours under a nitrogen gas flow containing 4% hydrogen.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1.
FIG. 8 shows the X-ray diffraction measurement results of this phosphor, FIG. 9 shows the emission spectrum, and Table 2 summarizes the characteristics.

<Comparative example 2>
Except that BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , SiO ₂ were measured as raw material compounds so that the molar ratio of Ba, Ca, Eu, Si was 1.75: 0.2: 0.005: 1. A phosphor Ba _1.75 Ca _0.2 Eu _0.005 SiO ₄ was produced in the same manner as in Example 1.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1.
FIG. 10 shows the X-ray diffraction measurement results of this phosphor, FIG. 11 shows the emission spectrum, and Table 2 summarizes the characteristics.

<Comparative Example 3>
Except that BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , SiO ₂ were measured as raw material compounds so that the molar ratio of Ba, Ca, Eu, Si was 1.0: 0.95: 0.005: 1. In the same manner as in Example 1, a phosphor Ba _1.00 Ca _0.95 Eu _0.005 SiO ₄ was obtained.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1.
FIG. 12 shows the X-ray diffraction measurement results of this phosphor, FIG. 11 shows the emission spectrum, and Table 2 summarizes the characteristics.

<Comparative example 4>
BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , and SiO ₂ as raw material compounds are weighed so that the molar ratio of Ba, Ca, Eu, and Si is 1.46: 0.49: 0.05: 1, and flux NH ₄ Cl was added and mixed with a ball mill for 1 hour. The raw material mixture was weighed in a small alumina crucible with a lid, lightly capped, and placed on the bottom of a large alumina crucible. The gap between the large crucible and the small crucible was not filled with activated carbon. In this state, phosphor Ba _1.46 Ca _0.49 Eu _0.05 SiO ₄ was produced by heating at 1200 ° C. for 4 hours under a nitrogen gas flow.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
The phosphor hardly emits light. Table 2 summarizes the characteristics of this phosphor.

<Comparative Example 5>
Implementation was performed except that BaCO ₃ , CaCO ₃ , Eu ₂ O ₃ , and SiO ₂ were measured as raw material compounds so that the molar ratio of Ba, Ca, Eu, and Si was 1.35: 0.45: 0.2: 1. In the same manner as in Example 1, a phosphor Ba _1.35 Ca _0.45 Eu _0.2 SiO ₄ was produced.
The X-ray diffraction measurement of this phosphor was performed under the same conditions as in Example 1. The X-ray diffraction measurement result was not different from Example 2.
FIG. 11 shows the emission spectrum of this phosphor, and Table 2 summarizes its characteristics.

From the above results, the following is clear.
In Examples 1 to 6, phosphors were produced by firing all of the raw material mixture having the composition range of claim 1 in a coexisting state of carbon. The phosphors thus obtained were all shown to be a crystal phase satisfying the conditions defined in claim 2 from the results of X-ray diffraction.

  On the other hand, Comparative Example 1 was fired with a merwinite composition and showed a merwinite crystal structure. Since the compositions of Comparative Examples 2 and 3 were outside the scope of the present invention, the same crystal structure as that of Examples 1 to 6 could not be obtained despite firing in the presence of carbon.

  Considering the emission characteristics, the emission peak wavelengths of Examples 1 to 6 are in the range of 445 nm to 471 nm, and the half width is 69 nm to 113 nm. On the other hand, Comparative Example 1 showed an emission peak wavelength of 440 nm and a narrow half-value width of 33 nm. The half widths of the emission peaks of Comparative Examples 2 and 3 were 80 nm and 110 nm, respectively, but the peak wavelengths were 530 nm and 509 nm, respectively. Comparative Example 4 had the same composition as Example 3, but did not emit light because it was not fired in the presence of carbon. In Comparative Example 5, since the Eu concentration was high, the emission peak wavelength was a long wavelength of 490 nm or more.

It is typical sectional drawing which shows embodiment of the light-emitting device of this invention. It is typical sectional drawing which shows an example of the surface emitting illumination apparatus using the light-emitting device of this invention. It is a typical perspective view which shows other embodiment of the light-emitting device of this invention. 2 is an X-ray diffraction pattern (X-ray source: CuKα) diagram of the phosphor of Example 1. FIG. FIG. 3 is an emission spectrum (excitation light: 400 nm) diagram of the phosphor of Example 1. 6 is an X-ray diffraction pattern (X-ray source: CuKα) diagram of the phosphor of Example 2. FIG. It is an emission spectrum (excitation light: 400 nm) figure of the fluorescent substance of Examples 2-6. 4 is an X-ray diffraction pattern (X-ray source: CuKα) diagram of the phosphor of Comparative Example 1. FIG. FIG. 3 is an emission spectrum (excitation light: 400 nm) of the phosphor of Comparative Example 1. 6 is an X-ray diffraction pattern (X-ray source: CuKα) diagram of a phosphor of Comparative Example 2. FIG. It is an emission spectrum (excitation light: 400 nm) figure of the fluorescent substance of the comparative examples 2, 3, and 5. It is an X-ray diffraction pattern (X-ray source: CuKα) diagram of the phosphor of Comparative Example 3.

DESCRIPTION OF SYMBOLS 1; Light-emitting device 2; Mount lead 3; Inner lead 4; 1st light-emitting body 5; Phosphor containing resin part (2nd light-emitting body)
6; Conductive wire 7; Mold member 8; Surface-emitting illuminating device 9; Diffuser 10; Holding case 11; Second light emitter 12; First light emitter 13;

Claims (8)

Composition formula: In _{(Ba a Ca b Sr c Mg} d Eu x) blue-emitting phosphor consisting of europium-activated alkaline earth metal silicate represented by SiO _4,
In the composition formula, coefficients a, b, c, d, and x are a + b + c + d + x = 2.
0 <a <2
0 <b <2
0 ≦ c <0.5
0 ≦ d <0.5
0 <x ≦ 0.5
A blue-emitting phosphor characterized by satisfying 2. The phosphor according to claim 1, comprising a specific crystal phase satisfying the following conditions (1) and (2) in an X-ray diffraction measurement using a CuKα X-ray source: Phosphor.
(1) A diffraction peak is observed in a diffraction angle (2θ) range of 21.30 to 22.50 ° (R ₀ ). This diffraction peak is defined as a reference diffraction peak (P ₀ ), and a Bragg angle (θ ₀ ) of P ₀ is used. ) When the following ranges of the five diffraction angles are R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ , at least one diffraction peak exists in each of these ranges.
(2) P ₀ is a diffraction peak height ratio of 20% with respect to the strongest diffraction peak among a total of six diffraction peaks of the reference diffraction peak P ₀ and the peaks existing in the range of R _{1 to} R _5. The other diffraction peaks have the above intensity, and the diffraction peak height ratio is 9% or more.
However, in any of the above (1) and (2), when two or more diffraction peaks exist in one angle range, a peak having a high intensity is adopted.
R ₁ : 2 × arcsin {sin (θ ₀ ) / (0.720 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.720 × 0.985)}
R ₂ : 2 × arcsin {sin (θ ₀ ) / (0.698 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.698 × 0.985)}
R ₃ : 2 × arcsin {sin (θ ₀ ) / (0.592 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.592 × 0.985)}
R ₄ : 2 × arcsin {sin (θ ₀ ) / (0.572 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.572 × 0.985)}
R ₅ : 2 × arcsin {sin (θ ₀ ) / (0.500 × 1.015)}
˜2 × arcsin {sin (θ ₀ ) / (0.500 × 0.985)}   3. The blue phosphor according to claim 1, wherein the coefficients a and b satisfy 1 ≦ (a / b) ≦ 10. 4.   The method for producing a phosphor according to any one of claims 1 to 3, wherein an element source compound of Ba, Ca, Eu and Si and an element source compound of Sr and / or Mg used as necessary A method for producing a blue-emitting phosphor, comprising firing the mixture in the presence of carbon.   In a light emitting device including a first light emitter that generates light having a wavelength of 420 nm or less and a second light emitter that generates visible light by irradiation of light from the first light emitter, the second light emitter A light emitting device comprising the phosphor according to any one of claims 1 to 3 or the phosphor obtained by the manufacturing method according to claim 4.   An illumination device using the light emitting device according to claim 5.   A display backlight comprising the light-emitting device according to claim 5.   A display using the light-emitting device according to claim 5.

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