JP2017008184A - Fluophor, light-emitting device, lighting system and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel fluophor useful for white emission LED applications.SOLUTION: A fluophor contains a crystal phase having a composition represented by the following formula [1], and has an emission peak wavelength in a range of 470 nm to 530 nm by irradiating excitation light having a wavelength of 280 nm to 450 nm. The formula [1] is MCaAlSiN, where M represents an activation element, m, a, b, c and d are each independently a value satisfying the following formulas of 0<m≤0.2, m+a=1, 0.8≤b≤1.2, 3.2≤c≤4.8 and 5.6≤d≤8.4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phosphor, a light emitting device, a lighting device, and an image display device.

In recent years, with the trend of energy saving, there is an increasing demand for illumination or backlight using LEDs. The LED used here is a white light emitting LED in which a phosphor is arranged on an LED chip that emits light of blue or near ultraviolet wavelength.
As such a type of white light emitting LED, in recent years, a blue LED chip using a phosphor that emits green light to yellow light using blue light from the blue LED chip as excitation light has been used.
Especially in display applications, among these three colors of blue, green and red, green has a particularly high visual sensitivity to human eyes and contributes greatly to the overall brightness of the display. Therefore, development of a green phosphor that is particularly important and excellent in light emission characteristics is desired.

Various phosphors emitting blue to blue-green have been developed. For example, in Patent Document 1, Eu ²⁺ activated barium magnesium aluminate phosphor or Eu ²⁺ activated alkaline earth chlorophosphate phosphor is used. It is disclosed. In Non-Patent Document 1, a nitride phosphor represented by a composition formula of BaSi ₄ Al ₃ N ₉ : Eu ²⁺ has been developed.
As a phosphor that emits green light, for example, in Patent Document 2, a composite oxynitride represented by a composition formula of Ba ₃ Si ₆ O ₁₂ N ₂ : Eu, Ce has been developed as a broadband phosphor.
As a yellow phosphor, a YAG (yttrium, aluminum, garnet) phosphor is known. For example, Patent Document 3 discloses that light emission characteristics are improved by using a flux.
Further, as other yellow to orange phosphors, for example, in Patent Document 4, an α sialon phosphor represented by a composition formula of Sr _1.11 Al _2.25 Si _9.75 N ₁₆ : Eu _0.02 is used. It is disclosed.

JP 2013-12711 A International Publication No. 2007/088966 Pamphlet JP 2010-163555 A JP 2009-256558 A

Chemistry of Materials 2014, 26, 4280-4288

As described above, various phosphors have been developed. Further, phosphors with improved light emission characteristics are desired.
In view of the above problems, the present invention provides a novel phosphor useful for white light emitting LED applications.
The present invention also provides a light emitting device including a novel phosphor, and an illumination device and an image display device including the light emitting device.

In view of the above-mentioned problems, the present inventors diligently studied new phosphors, and as a result, came up with a new phosphor that has a crystal structure different from that of conventional phosphors and is effectively used for LED applications. Completed the invention.
The present invention is as follows.
<1>
Including a crystal phase having a composition represented by the following formula [1],
A phosphor having an emission peak wavelength in a range of 470 nm to 530 nm by irradiating excitation light having a wavelength of 280 nm to 450 nm.
_{M m Ca a Al b Si c} N d [1]
(In the above formula [1],
M represents an activation element,
m, a, b, c, and d are values satisfying the following formulas independently.
0 <m ≦ 0.2
m + a = 1
0.8 ≦ b ≦ 1.2
3.2 ≦ c ≦ 4.8
5.6 ≦ d ≦ 8.4)
<2>
The phosphor according to <1>, further having an emission peak wavelength in a range of 580 nm or more and 620 nm or less.
<3>
A first illuminant, and a second illuminant that emits visible light when irradiated with light from the first illuminant, wherein the second illuminant is the fluorescence according to <1> or <2>. A light-emitting device comprising a body.
<4>
An illumination device comprising the light-emitting device according to <3> as a light source.
<5>
An image display device comprising the light-emitting device according to <3> as a light source.

The phosphor of the present invention has a crystal structure different from that of conventional phosphors, and is useful for white light emitting LED applications.
In addition, the light emitting device including the phosphor of the present invention, and the illumination device and the image display device including the light emitting device are of high quality.

It is an image by the scanning electron microscope of the fluorescent substance obtained in Example 1 (drawing substitute photograph). 2 is a diagram showing a powder X-ray diffraction (XRD) pattern of the phosphor obtained in Example 1. FIG. FIG. 3 is a diagram showing excitation / emission spectra of the phosphor obtained in Example 1. The broken line represents the excitation spectrum, and the solid line represents the emission spectrum.

Hereinafter, the present invention will be described with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and may be arbitrarily modified without departing from the gist of the present invention. Can be implemented.
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. Further, in the phosphor composition formula in this specification, each composition formula is delimited by a punctuation mark (,). In addition, when a plurality of elements are listed separated by commas (,), one or two or more of the listed elements may be included in any combination and composition. For example, the composition formula “(Ca, Sr, Ba) Al ₂ O ₄ : Eu” has “CaAl ₂ O ₄ : Eu”, “SrAl ₂ O ₄ : Eu”, and “BaAl ₂ O ₄ : Eu”. “Ca _1−x Sr _x Al ₂ O ₄ : Eu”, “Sr _1−x Ba _x Al ₂ O ₄ : Eu”, “Ca _1−x Ba _x Al ₂ O ₄ : Eu”, _{"Ca 1-x-y Sr x} Ba y Al 2 O 4: Eu " (. in the formula, 0 <x <1,0 <y <1,0 < a x + y <1) all the comprehensive It shall be shown in

  The present invention includes the phosphor according to the first embodiment, the light emitting device according to the second embodiment, the illumination device according to the third embodiment, and the image display device according to the fourth embodiment.

<About phosphor>
[Regarding Formula [1]]
The phosphor according to the first embodiment of the present invention includes a crystal phase having a composition represented by the following formula [1],
It is characterized by having an emission peak wavelength in a range of 470 nm to 530 nm by irradiating excitation light having a wavelength of 280 nm to 450 nm.
_{M m Ca a Al b Si c} N d [1]
(In the above formula [1],
M represents an activation element,
m, a, b, c, and d are values satisfying the following formulas independently.
0 <m ≦ 0.2
m + a = 1
0.8 ≦ b ≦ 1.2
3.2 ≦ c ≦ 4.8
5.6 ≦ d ≦ 8.4)

  In the formula [1], as the activation element M, europium (Eu), manganese (Mn), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium ( It represents one or more elements selected from the group consisting of Dy), holmium (Ho), erbium (Er), thulium (Tm) and ytterbium (Yb). M preferably contains at least Eu, and more preferably Eu.

Further, all or part of Eu may be substituted with at least one element selected from the group consisting of Ce, Pr, Sm, Tb, and Yb, and Ce is more preferable in terms of emission quantum efficiency.
That is, M is more preferably Eu and / or Ce, and more preferably Eu.
The ratio of Eu with respect to the entire activation element is preferably 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

In formula [1], Ca represents calcium. Ca may be partially substituted with other divalent elements such as magnesium (Mg), strontium (Sr), barium (Ba), zinc (Zn) and the like.
In particular, when a part of Ca is replaced with Sr, up to 50% of Ca can be replaced. When a part of Ca is replaced with Ba, it is possible to replace up to 20% of Ca.

  In formula [1], Al represents aluminum. Al is another trivalent element such as boron (B), gallium (Ga), indium (In), scandium (Sc), yttrium (Y), lanthanum (La), gadolinium (Gd), lutetium (Lu). ) Etc. may be partially substituted.

  In formula [1], Si represents silicon. Si may be partially substituted with other tetravalent elements such as germanium (Ge), tin (Sn), titanium (Ti), zirconium (Zr), hafnium (Hf), and the like.

  In formula [1], N represents a nitrogen element. N may be partially substituted with other elements such as oxygen (O), halogen atoms (fluorine (F), chlorine (Cl), bromine (Br), iodine (I)) and the like.

Oxygen may be mixed as an impurity in the raw material metal, or may be introduced during a manufacturing process such as a pulverization process or a nitriding process, and is inevitably mixed in the phosphor of this embodiment.
In addition, when a halogen element is contained, it may be mixed as an impurity in the raw material metal or introduced during a manufacturing process such as a pulverization process or a nitriding process. In particular, when a halide is used as a flux, a phosphor May be included.

  m represents the content of the activating element M, the range is usually 0 <m ≦ 0.2, and the lower limit is preferably 0.001, more preferably 0.01, and particularly preferably 0.00. 02, and the upper limit thereof is preferably 0.15, more preferably 0.12, and still more preferably 0.1.

a represents the content of Ca.
The relationship between m and a is usually
m + a = 1
Satisfied.

b represents the content of Al, the range is usually 0.8 ≦ b ≦ 1.2, the lower limit is preferably 0.9, and the upper limit is preferably 1.1.
c represents the content of Si, and the range is usually 3.2 ≦ c ≦ 4.8, and the lower limit is preferably 3.4, more preferably 3.6, and still more preferably 3.8. The upper limit is preferably 4.6, more preferably 4.4, and still more preferably 4.2.
d represents the content of N, the range is usually 5.6 ≦ c ≦ 8.4, the lower limit is preferably 6.3, and the upper limit is preferably 7.7. is there.

Any content is within the above-described range, which is preferable in terms of good emission characteristics of the obtained phosphor, particularly emission luminance.
The phosphor according to the first embodiment of the present invention can replace Si—N and Al—O while maintaining the crystal structure in the crystal structure. When Al is increased with respect to Si, O can be introduced into the N site while maintaining the charge compensation relationship.

<Physical properties of phosphor>
[Luminescent color]
The emission color of the phosphor of this embodiment is excited by light in the near ultraviolet region to blue region having a wavelength of 280 nm to 450 nm by adjusting the chemical composition and the like, and is blue, blue green, green, yellow green, yellow, orange , Red, etc., and a desired emission color can be obtained.

[Emission spectrum]
The phosphor of this embodiment preferably has the following characteristics when an emission spectrum is measured when excited with light having a wavelength of 280 nm to 450 nm.
The phosphor of this embodiment has a peak wavelength in the above-described emission spectrum of usually 470 nm or more, preferably 480 nm or more, more preferably 490 nm or more. Moreover, it is 530 nm or less normally, Preferably it is 520 nm or less, More preferably, it is 510 nm or less.
Moreover, it is preferable that the phosphor of this embodiment further has an emission peak on the longer wavelength side than the above. The second peak wavelength of the phosphor of this embodiment is usually 580 nm or more, preferably 585 nm or more, more preferably 590 nm or more, more preferably 595 nm or more, and usually 620 nm or less, preferably 615 nm or less, more preferably It is 610 nm or less, more preferably 605 nm or less.

  In order to excite the phosphor of this embodiment with light having a wavelength of 280 nm or more and 450 nm or less, for example, a GaN-based LED can be used. In addition, the measurement of the emission spectrum of the phosphor of this embodiment and the calculation of the emission peak wavelength, peak relative intensity and peak half width are, for example, a 150 W xenon lamp as an excitation light source and a multichannel CCD detector as a spectrum measurement device. It can be performed using a fluorescence measuring apparatus (manufactured by JASCO Corporation) equipped with C7041 (manufactured by Hamamatsu Photonics).

[Excitation wavelength]
The phosphor of this embodiment has an excitation peak in a wavelength range of usually 280 nm or more, preferably 300 nm or more, and usually 450 nm or less, preferably 420 nm or less, more preferably 400 nm or less, and further preferably 380 nm or less. That is, it is excited by light in the near ultraviolet to blue region.

[Crystal system and space group]
The crystal system in the phosphor of this embodiment is orthorhombic.
In addition, the space group in the phosphor of the present embodiment is not particularly limited as long as the average structure indicates a repetition period of the above length, but “International Tables for
No. 33 (Pna2 ₁ ) based on Crystallography (Third, revised edition), Volume A SPACE-GROUP SYMMETRY.
Here, the lattice constant and the space group can be obtained according to a conventional method. If it is a lattice constant, the results of X-ray diffraction and neutron diffraction can be obtained by Rietveld analysis, and if it is a space group, it can be obtained by electron beam diffraction.
In such a crystal structure, the activating element M is in a solution-substituted state at the Sr site.

[Lattice constant]
The lattice constant of the phosphor of this embodiment is as follows.
The a-axis is usually 11.33 mm or more, preferably 11.57 mm or more, and is usually 12.4 mm or less, preferably 11.8 mm or less, more preferably 11.74 mm or less.
The b-axis is usually 20.37 mm or more, preferably 20.79 mm or more, and usually 21.63 mm or less, preferably 21.30 mm or less, more preferably 21.21 mm or less.
The c-axis is usually 4.77 mm or more, preferably 4.87 mm or more, and usually 5.07 mm or less, preferably 4.97 mm or less, more preferably 4.95 mm or less.
It is preferable that all of the a-axis, b-axis, and c-axis are within the above ranges because crystals are stably generated, generation of impurity phases is suppressed, and light emission luminance is improved.

[Unit cell volume]
In the phosphor of the present embodiment, the unit cell volume calculated from the lattice constant (V) is usually 1110.75A ³ or more, preferably 1159.05A ³ or more, more preferably 1195.27A ³ or more, Usually 1303.93A ³ or less, preferably 1255.63A ³ or less, more preferably 1247.11A ³ or less, further preferably 1219.41A ³ or less.
Within the above range, it is preferable because crystals are stably generated, generation of impurity phases is suppressed, and light emission luminance is improved.

[Ratio of a-axis to c-axis (a / c)]
In the phosphor of this embodiment, the ratio of the a axis to the c axis (a / c) is usually 2.24 or more, preferably 2.33 or more, more preferably 2.36 or more, and usually 2.52 or less. Preferably it is 2.42 or less.
Within the above range, it is preferable because crystals are stably generated, generation of impurity phases is suppressed, and light emission luminance is improved.

<Method for producing phosphor>
The raw materials, the phosphor production method, and the like for obtaining the phosphor of this embodiment are as follows.
The method for producing the phosphor of the present embodiment is not particularly limited. For example, the raw material of the element M as an activator (hereinafter referred to as “M source” as appropriate) and the Ca raw material (hereinafter referred to as “Ca source” as appropriate). ), A raw material of Al (hereinafter referred to as “Al source” as appropriate), and a raw material of Si (hereinafter referred to as “Si source” as appropriate) are mixed with each other so as to have a composition represented by the formula [1]. (Mixing step), the obtained mixture can be baked (baking step).
Hereinafter, for example, the raw material of the element Eu may be referred to as “Eu source”, and the raw material of the element Sm may be referred to as “Sm source”.

[Phosphor material]
The phosphor raw materials (that is, the M source, the Ca source, the Al source, and the Si source) used in the manufacture of the phosphor of this embodiment include metals, alloys, and imides of each of the elements M, Ca, Al, and Si. Examples thereof include compounds, oxynitrides, nitrides, oxides, hydroxides, carbonates, nitrates, sulfates, oxalates, carboxylates, and halides. From these compounds, the reactivity to the composite oxynitride and the low generation amount of NOx, SOx, etc. during firing may be selected as appropriate.

(M source)
Of the M sources, specific examples of Eu sources include Eu ₂ O ₃ , Eu ₂ (SO ₄ ) ₃ , Eu ₂ (C ₂ O ₄ ) ₃ · 10H ₂ O, EuCl ₂ , EuCl ₃ , Eu (NO _{3 ) 3 · 6H 2 O, EuN} , EuNH and the like. Of these, Eu ₂ O ₃ , EuN and the like are preferable, and EuN is particularly preferable.
In addition, as specific examples of raw materials of other activating elements such as Sm source, Tm source, Yb source, etc., compounds in which Eu is replaced with Sm, Tm, Yb, etc. in the respective compounds listed as specific examples of Eu source Is mentioned.

(Ca source)
Specific examples of the Ca source include CaO, Ca (OH) ₂ , CaCO ₃ , Ca (NO ₃ ) ₂ .4H ₂ O, CaSO ₄ .2H ₂ O, Ca (C ₂ O ₄ ) · H ₂ O, and Ca. _{(OCOCH 3) 2 · H 2} O, CaCl 2, Ca 3 N 2, CaNH and the like. Among these, CaO, CaCO ₃ , Ca ₂ N, and Ca ₃ N ₂ are preferable, and Ca ₂ N and Ca ₃ N ₂ are particularly preferable. Further, those having a small particle size from the viewpoint of reactivity and high purity from the viewpoint of light emission efficiency are preferable.
Specific examples of the other divalent element raw materials include compounds in which Ca is replaced with Mg, Sr, Ba, Zn, or the like in each of the compounds listed as specific examples of the Ca source.

(Al source)
Specific examples of the Al source include AlN, Al ₂ O ₃ , Al (OH) ₃ , AlOOH, Al (NO ₃ ) _{3 and the} like. Among these, AlN and Al ₂ O ₃ are preferable, and AlN is particularly preferable. Moreover, as AlN, the thing with a small particle size from a reactive point and a high purity from the point of luminous efficiency is preferable.
Specific examples of other trivalent element materials include compounds in which Al is replaced with B, Ga, In, Sc, Y, La, Gd, Lu, or the like in each of the compounds listed as specific examples of the Al source. Is mentioned.

(Si source)
As a specific example of the Si source, it is preferable to use SiO ₂ or Si ₃ N ₄ . It is also possible to use a compound as a SiO _2. Specific examples of such a compound include SiO ₂ , H ₄ SiO ₄ , Si (OCOCH ₃ ) _{4 and the} like. Further, Si ₃ N ₄ is preferably one having a small particle diameter and high purity in terms of light emission efficiency from the viewpoint of reactivity. Furthermore, the thing with few content rates of the carbon element which is an impurity is preferable.
Specific examples of other raw materials for tetravalent elements include compounds in which Si is replaced by Ge, Ti, Zr, Hf, etc. in the respective compounds listed as specific examples of the Si source.

  Each of the above-described M source, Ca source, Al source, and Si source may be used alone or in combination of two or more in any combination and ratio.

[Mixing process]
Weigh the phosphor materials so that the desired composition is obtained, mix them well using a ball mill, etc., fill them in a crucible, fire them under a predetermined temperature and atmosphere, and pulverize and wash the fired product. The phosphor of the aspect can be obtained.

The mixing method is not particularly limited, and may be either a dry mixing method or a wet mixing method.
Examples of the dry mixing method include a ball mill.
As the wet mixing method, for example, a solvent or dispersion medium such as water is added to the above-described phosphor raw material, mixed using a mortar and pestle, and in a solution or slurry state, spray drying, heat drying, Alternatively, it is a method of drying by natural drying or the like.

[Baking process]
The obtained mixture is filled in a heat-resistant container such as a crucible or a tray made of a material having low reactivity with each phosphor raw material. The material of the heat-resistant container used at the time of firing is not particularly limited as long as the effects of the present embodiment are not impaired, but for example, a crucible such as boron nitride is preferably exemplified.

Although the firing temperature varies depending on other conditions such as pressure, the firing can be usually performed in a temperature range of 1900 ° C. or more and 2200 ° C. or less. The maximum temperature reached in the firing step is usually 1900 ° C or higher, preferably 1950 ° C or higher, more preferably 2000 ° C or higher, and usually 2200 ° C or lower, preferably 2150 ° C or lower.
If the calcination temperature is too high, nitrogen will fly and tend to produce defects in the host crystal and color, while if it is too low, the progress of the solid phase reaction will tend to be slow, making it difficult to obtain the target phase as the main phase. .

  The pressure during the firing step varies depending on the firing temperature and the like, but is usually 0.2 MPa or more, preferably 0.4 MPa or more, and is usually 200 MPa or less, preferably 190 MPa or less.

When firing at a pressure of 10 MPa or less in the firing step, the highest temperature achieved during firing is usually 1900 ° C or higher, preferably 1950 ° C or higher, more preferably 2000 ° C or higher, and usually 2200 ° C or lower, preferably 2100 ° C. It is as follows.
If the firing temperature is less than 1900 ° C., the solid phase reaction does not proceed, so that only the impurity phase or the unreacted phase appears, and it may be difficult to obtain the target phase as the main phase.

  Moreover, even if a very small target crystal phase is obtained, there is a possibility that the element that becomes the light emission center, particularly the Eu element, is not diffused in the crystal and the quantum efficiency is lowered. If the firing temperature is too high, the elements constituting the target phosphor crystal are likely to volatilize, and there is a high possibility that another phase will be formed as an impurity by forming or decomposing lattice defects.

  The heating rate in the firing step is usually 2 ° C./min or more, preferably 5 ° C./min or more, more preferably 10 ° C./min or more, and usually 30 ° C./min or less, preferably 25 ° C./min or less. It is. If the rate of temperature rise is below this range, the firing time may be long. In addition, if the rate of temperature rise exceeds this range, the firing device, container, etc. may be damaged.

  The firing atmosphere in the firing step is arbitrary as long as the phosphor of the present embodiment is obtained, but a nitrogen-containing atmosphere is preferable. Specific examples include a nitrogen atmosphere and a hydrogen-containing nitrogen atmosphere, and a nitrogen atmosphere is particularly preferable. The oxygen content in the firing atmosphere is usually 10 ppm or less, preferably 5 ppm or less.

  The firing time varies depending on the firing temperature, pressure, etc., but is usually 10 minutes or longer, preferably 30 minutes or longer, and usually 72 hours or shorter, preferably 12 hours or shorter. If the firing time is too short, grain formation and grain growth cannot be promoted, so that a phosphor with good characteristics cannot be obtained. If the firing time is too long, volatilization of the constituent elements is promoted, so atomic deficiency As a result, defects may be induced in the crystal structure and a phosphor having good characteristics may not be obtained.

In the case of producing the phosphor of the present embodiment, during the sintering step, for _example, it is preferable to use _{Mg 3 N 2, Li 3 N} , Na 3 N and the like as flux (crystal growth supplements).

[Post-processing process]
The obtained fired product is granular or massive. This is pulverized, pulverized and / or classified into a powder of a predetermined size. _Here, it is preferable to process as _{D 50} is less than about 30 [mu] m.
Specific examples of the treatment include a method of subjecting the synthesized product to sieve classification with an opening of about 45 μm, and passing the powder that has passed through the sieve to the next step, or the synthesized product to a general method such as a ball mill, a vibration mill, or a jet mill. The method of grind | pulverizing to a predetermined particle size using a grinder is mentioned. In the latter method, excessive pulverization not only generates fine particles that easily scatter light, but also generates crystal defects on the particle surface, which may cause a decrease in luminous efficiency.

Moreover, you may provide the process of wash | cleaning fluorescent substance (baked material) as needed. After the cleaning step, the phosphor is dried until it has no adhering moisture and is used. Further, if necessary, dispersion / classification treatment may be performed to loosen the aggregation.
Note that the phosphor of this embodiment may be formed by a so-called alloy method in which a constituent metal element is alloyed in advance and nitrided.

<Phosphor-containing composition>
The phosphor according to the first embodiment of the present invention can be used by mixing with a liquid medium. In particular, when the phosphor according to the first embodiment of the present invention is used for a light emitting device or the like, it is preferable to use the phosphor in a form dispersed in a liquid medium. What dispersed the fluorescent substance which concerns on 1st embodiment of this invention in the liquid medium as one embodiment of this invention is suitably with "the fluorescent substance containing composition which concerns on one embodiment of this invention", etc. Shall be called.

[Phosphor]
There is no restriction | limiting in the kind of fluorescent substance which concerns on the 1st embodiment of this invention contained in the fluorescent substance containing composition of this embodiment, It can select arbitrarily from what was mentioned above. Further, the phosphor according to the first embodiment of the present invention to be contained in the phosphor-containing composition of the present embodiment may be only one type, or two or more types may be used in combination in any combination and ratio. Also good. Furthermore, the phosphor-containing composition of the present embodiment may contain a phosphor other than the phosphor according to the first embodiment of the present invention as long as the effects of the present embodiment are not significantly impaired.

[Liquid medium]
The liquid medium used in the phosphor-containing composition of the present embodiment is not particularly limited as long as the performance of the phosphor is not impaired within the intended range. For example, any inorganic material and any material can be used as long as it exhibits liquid properties under the desired use conditions, suitably disperses the phosphor according to the first embodiment of the present invention, and does not cause an undesirable reaction. An organic material can be used, and examples thereof include a silicone resin, an epoxy resin, and a polyimide silicone resin.

[Content of liquid medium and phosphor]
The phosphor and the liquid medium content in the phosphor-containing composition of the present embodiment are arbitrary as long as the effects of the present embodiment are not significantly impaired, but for the liquid medium, the phosphor-containing composition of the present embodiment. The total amount is usually 50% by weight or more, preferably 75% by weight or more, and usually 99% by weight or less, preferably 95% by weight or less.

[Other ingredients]
In addition, you may make the fluorescent substance containing composition of this embodiment contain other components other than a fluorescent substance and a liquid medium, unless the effect of this embodiment is impaired remarkably. Moreover, only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

<Light emitting device>
A second embodiment of the present invention is a light-emitting device including a first light emitter (excitation light source) and a second light emitter that emits visible light when irradiated with light from the first light emitter. The second luminous body contains the phosphor according to the first embodiment of the present invention. Here, any one of the phosphors according to the first embodiment of the present invention may be used alone, or two or more thereof may be used in any combination and ratio.

  As the phosphor in this embodiment, for example, a phosphor that emits fluorescence in a blue or blue-green region under irradiation of light from an excitation light source is used. The phosphor is preferably a phosphor that emits fluorescence in the yellow to orange region. Specifically, when constituting a light emitting device, the blue or blue-green phosphor preferably has a light emission peak in a wavelength range of 470 nm to 530 nm. The phosphor preferably further has an emission peak in a wavelength range of 580 nm or more and 620 nm or less.

In this case, the light-emitting device of this embodiment uses, for example, a semiconductor light-emitting element having a light emission peak in the wavelength range of 280 nm to 450 nm as the first light emitter, and the first light emitter of the present invention as the second light emitter. The phosphor according to the embodiment can be used.

(Red phosphor)
In the above aspect, a red phosphor may be further used as necessary.
As the red phosphor, for example, the following phosphors are preferably used.
Examples of the Mn-activated fluoride phosphor include K ₂ (Si, Ti) F ₆ : Mn, K ₂ Si _1-x Na _x Al _x F ₆ : Mn (0 <x <1),
Examples of sulfide phosphors include (Sr, Ca) S: Eu (CAS phosphor), La ₂ O ₂ S: Eu (LOS phosphor),
Examples of the garnet phosphor include (Y, Lu, Gd, Tb) ₃ Mg ₂ AlSi ₂ O ₁₂ : Ce,
Examples of nanoparticles include CdSe,
Examples of the nitride or oxynitride phosphor include (Sr, Ca) AlSiN ₃ : Eu (S / CASN phosphor), (CaAlSiN ₃ ) _1-x · (SiO ₂ N ₂ ) _x : Eu (CASON fluorescence). Body), (La, Ca) ₃ (Al, Si) ₆ N ₁₁ : Eu (LSN phosphor), (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu (258 phosphor), ( _{Sr, Ca) Al 1 + x} Si 4-x O x N 7-x: Eu (1147 _{phosphors), M x (Si, Al} ) 12 (O, N) 16: Eu (M is, Ca, Sr, etc.) ( α sialon phosphor), Li (Sr, Ba) Al ₃ N ₄ : Eu (wherein x is 0 <x <1).

(Yellow phosphor)
In said aspect, you may use further the fluorescent substance (yellow fluorescent substance) which has the light emission peak of the range of 550-600 nm as needed.
For example, the following phosphors are preferably used as the yellow phosphor.
Examples of the garnet phosphor include (Y, Gd, Lu, Tb, La) ₃ (Al, Ga) ₅ O ₁₂ : (Ce, Eu, Nd),
Examples of the orthosilicate include (Ba, Sr, Ca, Mg) ₂ SiO ₄ : (Eu, Ce),
Examples of (acid) nitride phosphors include (Ba, Ca, Mg) Si ₂ O ₂ N ₂ : Eu (SION phosphor), (Li, Ca) ₂ (Si, Al) ₁₂ (O, N ₁₆ : (Ce, Eu) (α-sialon phosphor), (Ca, Sr) AlSi ₄ (O, N) ₇ : (Ce, Eu) (1147 phosphor)
Etc.
The phosphor is preferably a garnet phosphor, and most preferably a YAG phosphor represented by Y ₃ Al ₅ O ₁₂ : Ce.

[Configuration of light emitting device]
The light emitting device of this embodiment has a first light emitter (excitation light source) and uses at least the phosphor according to the first embodiment of the present invention as the second light emitter, The configuration is not limited, and a known device configuration can be arbitrarily employed.
Examples of the device configuration and the light emitting device include those described in Japanese Patent Application Laid-Open No. 2007-291352.
In addition, examples of the form of the light emitting device include a shell type, a cup type, a chip on board, a remote phosphor, and the like.

<Applications of light emitting device>
The use of the light-emitting device according to the second embodiment of the present invention is not particularly limited and can be used in various fields where a normal light-emitting device is used, but has a wide color reproduction range and color rendering properties. In particular, it is particularly preferably used as a light source for illumination devices and image display devices.

[Lighting device]
A third embodiment of the present invention is an illumination device including the light emitting device according to the second embodiment of the present invention as a light source.
When the light-emitting device according to the second embodiment of the present invention is applied to a lighting device, the light-emitting device as described above may be appropriately incorporated into a known lighting device. For example, a surface emitting illumination device in which a large number of light emitting devices are arranged on the bottom surface of the holding case can be used.

[Image display device]
According to a fourth embodiment of the present invention, there is provided an image display device comprising the light emitting device according to the second embodiment of the present invention as a light source.
When the light emitting device according to the second embodiment of the present invention is used as a light source of an image display device, the specific configuration of the image display device is not limited, but it is preferably used with a color filter. For example, when the image display device is a color image display device using color liquid crystal display elements, the light emitting device is used as a backlight, a light shutter using liquid crystal, and a color filter having red, green, and blue pixels; By combining these, an image display device can be formed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples without departing from the gist thereof.

<Measurement method>
[Luminescent characteristics]
The sample was packed in a copper sample holder, and the excitation emission spectrum and emission spectrum were measured using a fluorescence spectrophotometer FP-6500 (manufactured by JASCO). During the measurement, the slit width of the light-receiving side spectroscope was set to 1 nm and the measurement was performed. The emission peak wavelength (hereinafter sometimes referred to as “peak wavelength”) and the half width of the emission peak were read from the obtained emission spectrum.

[Elemental analysis]
In order to examine the composition of the phosphor obtained in the first embodiment of the present invention, the following elemental analysis was performed. After selecting several crystals by observation with a scanning electron microscope (SEM), each element is analyzed using an electron probe microanalyzer (wavelength dispersive X-ray analyzer: EPMA) JXA-8200 (manufactured by JEOL). Carried out.

[Crystal structure analysis]
X-ray diffraction data of single crystal particles was measured with a single crystal X-ray diffractometer R-AXIS RAPID-II (manufactured by Rigaku) equipped with an imaging plate and a graphite monochromator and using Mo Kα as an X-ray source. PROCESS-AUTO was used to collect data and refine the lattice constant, and NUMABS was used to correct X-ray shape absorption. The crystal structure parameters were refined for the F ² data using SHELXL-97.

<Synthesis of phosphor>
[Example 1]
The phosphors were prepared as follows using Ca ₃ N ₂ (manufactured by Shellac), EuN (manufactured by Shellac), Si ₃ N ₄ (manufactured by Ube Industries), and AlN (manufactured by Tokuyama). did.

The raw materials were weighed with an electronic balance so as to have the weights shown in Table 1, placed in an alumina mortar, and ground and mixed until uniform. Further, 0.11 g of Mg ₃ N ₂ (manufactured by Shellac Co.) was added to this mixed powder, and further pulverized and mixed. These operations were performed in a glove box filled with Ar gas.

About 0.5 g of the obtained raw material mixed powder was weighed and filled into a boron nitride crucible as it was. This crucible was placed in a vacuum pressure firing furnace (manufactured by Shimadzu Mectem Co.). Then, after reducing the pressure to 8 × 10 ⁻³ Pa or less, vacuum heating was performed from room temperature to 800 ° C. at a heating rate of 20 ° C./min. When the temperature reached 800 ° C., high-purity nitrogen gas (99.9995%) was introduced for 5 minutes until the pressure inside the furnace reached 0.85 MPa. After the introduction of the high purity nitrogen gas, while maintaining the furnace pressure at 0.85 MPa, the temperature was further increased to 1600 ° C. at a rate of temperature increase of 20 ° C./min and held for 1 hour. Furthermore, it heated to 2150 degreeC with the temperature increase rate of 20 degree-C / min, and when it reached 2150 degreeC, it hold | maintained for 4 hours. After calcination, it was cooled to 1200 ° C. at a temperature lowering rate of 20 ° C./min, and then allowed to cool. Transparent crystals were picked up from the obtained product to obtain the phosphor of Example 1.

  The result of having observed the fluorescent substance of Example 1 by the scanning electron microscope is shown in FIG. Table 2 shows the results of composition analysis of the phosphor crystals of Example 1.

  As shown in Table 2, in the phosphor of Example 1 of the present application, oxygen (O) element and magnesium (Mg) element were not detected. Therefore, mixing of oxygen and magnesium elements into the crystal phase is considered to be substantially zero.

Based on the above results, a single crystal structure analysis was performed with the composition formula of the phosphor of Example 1 as (Eu _0.01 Ca _0.99 ) AlSi ₄ N ₇ , and the lattice constant, space group, The coordinates of each atom (Table 3) were determined.

<Crystal structure analysis>
As a result of considering the fundamental reflection obtained by the single crystal X-ray diffraction of Example 1, a simple lattice (P lattice, lattice constant a = 11.6849 (5) Å, b = 2.0027 (9) Å, c = 4.9196 (2) Å, α = 90 °, β = 90 °, γ = 90 °). The numbers in parentheses after the above lattice constants represent standard deviations.

In addition, the reflection point of the obtained basic reflection was examined based on the extinction law, and the space group in the phosphor of Example ₁ was analyzed as Pna21. The results of the obtained crystal structure analysis are shown in Table 3. Eu is assumed to partially substitute the Sr site in the crystal structure.
Further, the X-ray diffraction pattern is simulated based on the coordinates obtained by the structural analysis, and the composition ratio calculated from the composition analysis result and the electron density is taken into consideration, and the phosphor according to the first embodiment of the present invention is used. The chemical composition was determined as (Eu _0.01 Ca _0.99 ) AlSi ₄ N ₇ .

The lattice constant obtained by structural analysis of the phosphor single crystal of Example 1 is used as an initial value, and FIG.
Table 4 shows the results obtained by refining the lattice constant of the phosphor of Example 1 powdered from the XRD pattern. A value almost coincident with the lattice constant obtained by single crystal X-ray diffraction was obtained, and it was confirmed that there was little variation for each crystal. The number in parentheses after the lattice constant represents the standard deviation.

The excitation / emission spectrum of the phosphor of Example 1 is shown in FIG. The excitation spectrum is a measurement result when emission at 500 nm is monitored and the emission spectrum is excited at 400 nm.
The phosphor of Example 1 has two emission peaks, a light emission spectrum having a first light emission peak wavelength of 500 nm and a second light emission peak of 608 nm, and has a whitish green color as shown in FIG. It was confirmed that luminescence was observed. Moreover, the excitation spectrum which shows that it can excite in the wide wavelength range from 280 nm to 450 nm was shown.

Claims (5)

Including a crystal phase having a composition represented by the following formula [1],
A phosphor having an emission peak wavelength in a range of 470 nm to 530 nm by irradiating excitation light having a wavelength of 280 nm to 450 nm.
_{M m Ca a Al b Si c} N d [1]
(In the above formula [1],
M represents an activation element,
m, a, b, c, and d are values satisfying the following formulas independently.
0 <m ≦ 0.2
m + a = 1
0.8 ≦ b ≦ 1.2
3.2 ≦ c ≦ 4.8
5.6 ≦ d ≦ 8.4)   The phosphor according to claim 1, further having an emission peak wavelength in a range of 580 nm or more and 620 nm or less.   A first illuminant and a second illuminant that emits visible light when irradiated with light from the first illuminant, wherein the second illuminant comprises the phosphor according to claim 1 or 2. A light-emitting device comprising:   An illumination device comprising the light-emitting device according to claim 3 as a light source. An image display device comprising the light-emitting device according to claim 3 as a light source.

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