JP2012144685A - Phosphor and light emitting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor excellent in light emission property when being excited with light in near-ultraviolet or blue region, and suitably usable, for example, in combination of a near-ultraviolet or blue LED and the phosphor.SOLUTION: The phosphor is represented by the composition formula (1): MEu(PO)(wherein M is a divalent metal element, and contains at least Sr and Ca; and p and q satisfies 0.02<p≤0.1 and 1.6≤q≤2.4).

Description

  The present invention relates to a phosphate phosphor that essentially contains Sr, Ca, and Eu, and a light-emitting device using the phosphor.

The phosphor is used for various applications such as a fluorescent display tube (VFD), a field emission display (FED), a plasma display panel (PDP), a cold cathode tube (CRT), and a white light emitting diode (white LED). . For example, a white LED can be configured by combining a blue LED with a Y ₃ Al ₅ O ₁₂ : Ce yellow phosphor (YAG phosphor). Further, natural phosphate minerals such as (Ca, Sr) ₃ (PO ₄ ) ₂ : Sn ²⁺ phosphor and Sr ₅ (PO ₄ ) 3Cl: Eu ²⁺ phosphor are used as phosphors for fluorescent lamps. ing. Further, Patent Documents 1 and ₂ disclose a Ca _3-x Sr _x-0.02 Eu _0.02 (PO ₄ ) ₂ phosphor as a green light-emitting phosphor for ultraviolet excitation. When this phosphor is excited with ultraviolet light having a wavelength of 280 nm, it has a light emission peak at 515 nm and exhibits green light emission with a half-value width of 98 nm.

JP 2008-2222988 A JP 2008-2222989 A

  In the phosphor disclosed in Patent Document 1 or the like, the light emission characteristics when excited by light in the near ultraviolet to blue region and the application to LED applications have not been studied.

  Therefore, the present invention provides a phosphor that has excellent light emission characteristics when excited with light in the ultraviolet to blue region (particularly near ultraviolet to blue light) and can be suitably used in combination with, for example, a blue LED. Let it be an issue.

In the phosphor of a Ca ₃ (PO ₄ ) ₂ —Sr (PO ₄ ) ₂ binary system, when the Eu ²⁺ concentration is higher than that of the conventional, the present inventors are excited by near ultraviolet or blue light. The inventors have found that the light emission characteristics are excellent and completed the present invention.

That is, the first aspect of the present invention is a phosphor represented by the following composition formula (1).
M _3-p Eu _p (PO ₄ ) _q (1)
(Here, M is a divalent metal element and contains at least Sr and Ca. Moreover, p and q satisfy the following expressions, respectively.
0.02 <p ≦ 0.1
1.6 ≦ q ≦ 2.4)

  In the composition formula (1) according to the first aspect of the present invention, in the element M, the molar ratio of Sr to the total mole of Sr and Ca is preferably 0.2 or more and 0.9 or less.

The phosphor according to the first aspect of the present invention has chromaticity coordinates (x, y) when excited with light having a peak wavelength of 405 nm.
0.3940 ≦ x ≦ 0.5500
0.4500 ≦ y ≦ 0.6200
It is preferable that

  When the phosphor according to the first aspect of the present invention is excited with light having a wavelength of 450 nm, the ratio of the emission intensity at 530 nm to the emission intensity at 600 nm is preferably 1.26 or less.

  A second aspect of the present invention includes a first light emitter, and a second light emitter capable of emitting light by converting light from the first light emitter into visible light, the second light emitter. A light-emitting device including the phosphor according to the first aspect of the present invention.

  In the second aspect of the present invention, the first light emitter preferably emits light having an emission peak in the wavelength range of 300 nm to 500 nm. Examples of the first light emitter include a near-ultraviolet light-emitting lamp, a semiconductor light-emitting device (LED) that emits ultraviolet to blue light, a semiconductor laser diode (LD), other inorganic electroluminescent devices, and organic electroluminescent devices. Preferably used.

  ADVANTAGE OF THE INVENTION According to this invention, the fluorescent substance excellent in the light emission characteristic when excited by ultraviolet thru | or blue light, especially near ultraviolet thru | or blue light can be provided. Further, since the phosphor of the present invention exhibits broad light emission over a wide wavelength range, when the light emitting device is configured by combining the phosphor of the present invention with a near-ultraviolet or blue light emitting LED, the present phosphor is used as the phosphor. Even when the phosphor of the invention is used alone, a light emitting device having high color rendering properties can be provided.

It is a figure which shows roughly the light-emitting device 10 of this invention which concerns on 1st Embodiment. It is a figure which shows schematically the light-emitting device 20 of this invention which concerns on 2nd Embodiment. It is a figure which shows schematically the light-emitting device 30 of this invention which concerns on 3rd Embodiment. It is a figure which shows roughly the illuminating device 100 in which the light-emitting device 20 was integrated. It is a figure which shows the emission spectrum at the time of exciting with the light of wavelength 450nm about the fluorescent substance which concerns on Example 1, 2 and the comparative example 1. FIG. It is a figure which shows the emission spectrum at the time of exciting with the light of wavelength 450nm about the fluorescent substance which concerns on Example 3 and Comparative Examples 2 and 3. FIG. It is a figure which shows the emission spectrum at the time of exciting with the light of wavelength 450nm about the fluorescent substance which concerns on Examples 4-7 and the comparative example 4. FIG. It is a figure which shows the emission spectrum at the time of exciting with the light of wavelength 450nm about the fluorescent substance which concerns on Example 8, 9 and the comparative example 5. FIG. It is a figure which shows the emission spectrum at the time of exciting with the light of wavelength 450nm about the fluorescent substance which concerns on Example 10 and Comparative Example 10. FIG. It is a figure which shows the X-ray-diffraction pattern about the fluorescent substance concerning Example 1, 2 and the comparative example 1. FIG. It is a figure which shows the emission spectrum of the semiconductor light-emitting device based on Example 11. It is a figure which shows the emission spectrum of the semiconductor light-emitting device based on Example 12.

1. Phosphor 1.1. Composition of phosphor The phosphor according to the present invention is a phosphor represented by the following composition formula (1).
M _3-p Eu _p (PO ₄ ) _q (1)
(Here, M is a divalent metal element and contains at least Sr and Ca. Moreover, p and q satisfy the following expressions, respectively.
0.02 <p ≦ 0.1
1.6 ≦ q ≦ 2.4)

  In the composition formula (1), the proportion of Sr and Ca in the entire M element, which is a divalent metal element, is preferably 80 mol% or more, and more preferably 90 mol% or more. As M element, Mg, Ba, etc. may be contained in addition to Sr and Ca.

About p of the said composition formula (1), it is 0.02 <p <= 0.1. By setting p in this range, the emission wavelength component near 600 nm is enhanced, and the emission spectrum is broadened from the green region to the orange region. In this case, the emission color tends to be yellow. The lower limit of p is preferably 0.025 or more, more preferably 0.030 or more, particularly preferably 0.050 or more, and the upper limit is preferably 0.090 or less, more preferably 0.085 or less. If p is too large, concentration quenching tends to occur, and if p is too small, yellow light emission tends not to occur.
Further, regarding q in the composition formula (1), 1.6 ≦ q ≦ 2.4, but the lower limit is preferably 1.8 or more, more preferably 1.9 or more, and the upper limit is preferably 2. .2 or less, more preferably 2.1 or less, and the closer to 2, the better. In such a range, since the crystal phase becomes a single phase, a phosphor having particularly excellent light emission characteristics can be obtained.

  In the composition formula (1), the lower limit of the molar ratio of Sr to the total moles of Sr and Ca in the element M is preferably 0.2 or more, more preferably 0.3 or more, and further preferably 0.4 or more. The upper limit is preferably 0.9 or less, more preferably 0.8 or less, and even more preferably 0.7 or less. In the case where the Eu concentration is in the specific range described above, when the molar ratio of Sr to the total mole of Sr and Ca is in such a range, a phosphor having particularly excellent yellow light emission characteristics can be obtained.

  In addition to the constituent elements of M (divalent metal element), Eu, P, and O described in the above formula (1), they are inevitably mixed within a range that does not affect the effect of the present invention. It may contain an impurity element.

1.2. Crystal Structure of Phosphor When the phosphor according to the present invention is analyzed by an X-ray diffractometer, the X-ray diffraction pattern is described in “AA Belik et al., Chem. Mater. 14 (2002) 3197-3205”. Β′-Ca _5/7 Sr _16/7 (PO ₄ ) ₂ is considered to belong to the whitlockite structure type.

1.3. Excitation / emission characteristics of phosphor The phosphor according to the present invention has chromaticity coordinates (x, y) of 0.3940 ≦ x ≦ 0.5500 and 0.4500 ≦ y when excited with light having a peak wavelength of 405 nm. It is preferable that ≦ 0.6200. For x, the lower limit is preferably 0.3944 or more, more preferably 0.3948 or more, and the upper limit is preferably 0.5400 or less, more preferably 0.5300 or less. As for y, the lower limit is preferably 0.4510 or more, more preferably 0.4520 or more, and the upper limit is preferably 0.6150 or less, more preferably 0.6100 or less.

  In the phosphor according to the present invention, when excited with light having a wavelength of 450 nm, the ratio of the emission intensity at 530 nm to the emission intensity at 600 nm is preferably 1.26 or less, and preferably 1.25 or less. More preferably, it is particularly preferably 1.24 or less. Although it does not specifically limit about a minimum, Preferably it is 0.60 or more, More preferably, it is 0.70 or more, More preferably, it is 0.80 or more.

  When the phosphor according to the present invention is excited with light having a peak wavelength of 405 nm or 450 nm, the emission spectrum preferably exhibits a broad shape including a green component to a red component.

  The emission spectrum of the phosphor according to the present invention usually rises from around the wavelength of 460 nm and emits light up to around the wavelength of 700 nm. One emission peak wavelength is usually in the range of 480 nm or more, preferably 500 nm or more, more preferably 510 nm or more, and usually 550 nm or less, preferably 545 nm or less, more preferably 540 nm or less. The peak is usually in the range of 560 nm or more, preferably 565 nm or more, more preferably 570 nm or more, and usually 630 nm or less, preferably 625 nm or less, more preferably 620 nm or less. The two emission peaks described above do not necessarily have a clear boundary, and may have a plateau shape.

  The shape of the emission spectrum of the phosphor according to the present invention varies depending on the composition of the contained crystal phase. For example, the shape of the emission spectrum changes depending on the ratio of Sr to the sum of Sr and Ca in the M element in the composition formula (1). Furthermore, the shape of the emission spectrum changes depending on the Eu concentration.

The reason why the emission color (the shape of the emission spectrum) changes depending on the Eu concentration can be considered as follows.
In general, in the whitlockite structure type crystal described above, there are five types of crystal positions occupied by Ca or Sr: three 8-coordinate positions, one 9-coordinate position, and one 6-coordinate position. Here, when the Eu ²⁺ concentration is low, Eu ²⁺ occupies a relatively wide crystal position (8 to 9 coordination), so Eu ²⁺ is affected by a relatively small crystal field, and the emission spectrum is as follows. The green emission peak will be emphasized. In contrast, when the Eu ²⁺ concentration is high, it becomes to occupy even Eu ²⁺ narrow crystal position (six-coordinate), Eu ²⁺ affected by large crystal field is to be increased. In such a case, one site of long-wavelength light emission is increased, and the light emission spectrum emphasizes not only green light emission but also light emission components in the yellow to orange region. That is, it is considered that when the Eu ²⁺ concentration is higher than the conventional one as in the phosphor represented by the composition formula (1), a broad emission spectrum over the green to orange region can be obtained.

  The phosphor according to the present invention has excellent emission characteristics when excited with ultraviolet or blue light having a wavelength of 300 nm or more, preferably 330 nm or more, more preferably 360 nm or more, 500 nm or less, preferably 480 nm or less, more preferably 460 nm or less. .

2. Method for Producing Phosphor The phosphor according to the present invention is prepared, for example, by weighing each phosphor material so as to have the composition represented by the above composition formula (1) to prepare a phosphor material mixture, and the obtained phosphor It can manufacture by baking a raw material mixture.

2.1. Phosphor raw material As the phosphor raw material, for example, at least an Sr compound and a Ca compound are used as a raw material constituting the M element, and further, an Eu compound or a phosphoric acid compound is used. The forms of the Sr compound and the Ca compound are not particularly limited, and a carbonate or the like may be used. The form of the Eu compound is not particularly limited, and an oxide or the like may be used. Moreover, as a phosphoric acid compound, although various phosphates can be used, what a cation volatilizes during a heating is preferable. For example, (NH ₄ ) ₃ PO ₄ .3H ₂ O, NH ₄ H ₂ PO _{4 and the} like. In addition, you may include Mg compound and Ba compound as a raw material which comprises M element. In addition, the phosphor material may contain inevitable impurities.

2.2. Mixing of phosphor raw materials Such phosphor raw materials are weighed and mixed so as to have the composition represented by the composition formula (1). The mixing method is not particularly limited, and examples thereof include the following methods (A) and (B).
(A) Dry pulverizer such as hammer mill, roll mill, ball mill, jet mill, etc., or pulverization using mortar and pestle, and mixer such as ribbon blender, V-type blender, Henschel mixer, or mortar and pestle And a dry mixing method in which the above phosphor raw materials are pulverized and mixed.
(B) A solvent or dispersion medium such as water is added to the phosphor material described above, and mixed using, for example, a pulverizer, a mortar and a pestle, or an evaporating dish and a stirring rod, to obtain a solution or slurry. A wet mixing method in which drying is performed by spray drying, heat drying, or natural drying.

  The mixing of the phosphor raw material may be either the wet mixing method or the dry mixing method, but in order to avoid contamination of the phosphor raw material with moisture, a dry mixing method or a wet mixing method using a water-insoluble solvent is more preferable. . A phosphor raw material mixture is obtained by mixing.

2.3. Calcination of the phosphor raw material mixture The phosphor according to the present invention can be manufactured by drying and baking the obtained phosphor raw material mixture as necessary. For example, the firing may be performed by filling a phosphor raw material mixture in a container such as a crucible and using a firing furnace, a pressure furnace, or the like. The firing conditions may be any conditions as long as the phosphor according to the present invention can be manufactured. As a result of investigations by the present inventors, it has been found that, for example, the phosphor can be appropriately manufactured under the following conditions.
Firing time: usually 0.5 hours or longer, preferably 1 hour or longer, and usually 10 hours or shorter, preferably 5 hours or shorter.
Firing temperature: usually 1200 ° C. or higher, preferably 1350 ° C. or higher, and usually 1600 ° C. or lower, preferably 1500 ° C. or lower.
Firing atmosphere: a mixed atmosphere of an inert gas and a reducing gas, a mixed atmosphere of nitrogen and a reducing gas, and the like are preferable, and a mixed atmosphere of argon and hydrogen is preferable.
Pressure during firing: Although pressure may be applied, it is usually 0.09 MPa or more and 0.11 MPa or less, and firing is preferably performed under normal pressure.
In addition, you may repeat baking several times as needed.

2.4. Post-treatment of phosphor The phosphor according to the present invention obtained after firing becomes granular or massive. This may be pulverized, pulverized, and / or classified into a predetermined size of powder. For example, it may be processed so that D50 is about 30 μm or less. 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 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.

3. Use of phosphor The phosphor according to the present invention can be used for any application using a phosphor. In addition, the phosphor according to the present invention can be used alone, but depending on the application, the phosphor according to the present invention and other phosphors may be used in combination, and used as a phosphor mixture of any combination. It is also possible. Moreover, the phosphor according to the present invention can be used as a phosphor-containing composition by mixing with a known liquid medium (for example, a silicone compound). Furthermore, the phosphor according to the present invention can be used in various light emitting devices by combining with a light source that emits near ultraviolet or blue light, taking advantage of its excellent emission characteristics when excited with near ultraviolet or blue light. It can be used suitably.

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

  The type of the liquid medium is not particularly limited, and a curable material that can be molded over the semiconductor light emitting element can be used. The curable material is a fluid material that is cured by performing some kind of curing treatment. Here, the fluid state means, for example, a liquid state or a gel state.

  The curable material is not particularly limited as long as it ensures the role of guiding light emitted from the solid light emitting element to the phosphor. Moreover, only 1 type may be used for a curable material and it may use 2 or more types together by arbitrary combinations and a ratio. Therefore, as the curable material, any of inorganic materials, organic materials, and mixtures thereof can be used.

  As the inorganic material that can be used as the curable material, for example, a solution obtained by hydrolytic polymerization of a solution containing a metal alkoxide, a ceramic precursor polymer or a metal alkoxide by a sol-gel method, or a combination thereof is solidified. Examples thereof include inorganic materials (for example, inorganic materials having a siloxane bond).

  On the other hand, examples of the organic material that can be used as the curable material include a thermosetting resin and a photocurable resin. Specific examples include (meth) acrylic resins such as poly (meth) acrylic acid methyl; styrene resins such as polystyrene and styrene-acrylonitrile copolymers; polycarbonate resins; polyester resins; phenoxy resins; butyral resins; Cellulose resins such as cellulose acetate and cellulose acetate butyrate; epoxy resins; phenol resins; silicone resins and the like.

  Among these curable materials, it is preferable to use a silicon-containing compound that is less deteriorated with respect to light emitted from the semiconductor light-emitting element and is excellent in alkali resistance, acid resistance, and heat resistance. A silicon-containing compound is a compound having a silicon atom in the molecule, organic materials such as polyorganosiloxane (silicone compounds), inorganic materials such as silicon oxide, silicon nitride, and silicon oxynitride, and borosilicates and phosphosilicates. Examples thereof include glass materials such as salts and alkali silicates. Among these, silicone materials are preferable from the viewpoints of transparency, adhesion, ease of handling, and excellent mechanical and thermal stress relaxation characteristics.

  The silicone-based material usually refers to an organic polymer having a siloxane bond as a main chain, and for example, condensation-type, addition-type, improved sol-gel type, photo-curing type silicone-based materials can be used. As the condensed silicone material, for example, semiconductor light-emitting device members described in JP-A-2007-112973 to 112975, JP-A-2007-19459, JP-A-2008-34833, and the like can be used. Condensation-type silicone materials have excellent adhesion to components such as packages, electrodes, and light-emitting elements used in semiconductor light-emitting devices, so the addition of adhesion-improving components can be minimized, and crosslinking is mainly due to siloxane bonds. There is an advantage of excellent heat resistance and light resistance.

  Examples of the addition-type silicone material include potting silicone materials described in JP-A-2004-186168, JP-A-2004-221308, JP-A-2005-327777, JP-A-2003-183881, Organically modified silicone materials for potting described in JP-A-2006-206919, silicone materials for injection molding described in JP-A-2006-324596, silicone materials for transfer molding described in JP-A-2007-231173, etc. Can be suitably used. The addition-type silicone material has advantages such as a high degree of freedom in selection such as a curing speed and a hardness of a cured product, a component that does not desorb during curing, hardly shrinking due to curing, and excellent deep part curability.

  Moreover, as an improved sol-gel type silicone material that is one of the condensation types, for example, the silicone materials described in JP-A-2006-077234, JP-A-2006-291018, JP-A-2007-119569 and the like are used. It can be used suitably. The improved sol-gel type silicone material has an advantage that it has a high degree of crosslinking, heat resistance, light resistance and durability, and is excellent in the protective function of a phosphor having low gas permeability and low moisture resistance.

As the photocurable silicone material, for example, silicone materials described in JP 2007-131812 A, JP 2007-214543 A, and the like can be suitably used. The ultraviolet curable silicone material has advantages such as excellent productivity because it cures in a short time, and there is no need to apply a high temperature for curing, and the light emitting element is hardly deteriorated.
These silicone materials may be used alone, or a mixture of a plurality of silicone materials may be used if curing inhibition does not occur when mixed.

  The content of the liquid medium is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 25% by weight or more, preferably 40% by weight or more, and usually 99% by weight with respect to the entire phosphor-containing composition. % By weight or less, preferably 95% by weight or less, more preferably 80% by weight or less. When the amount of the liquid medium is large, no particular problem occurs. However, in order to obtain a desired chromaticity coordinate, color rendering index, luminous efficiency, etc. in the case of a semiconductor light emitting device, it is usually at a blending ratio as described above. It is desirable to use a liquid medium. On the other hand, when there is too little liquid medium, fluidity | liquidity may fall and it may become difficult to handle.

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

  The phosphor content in the phosphor-containing composition is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 1% by weight or more, preferably 5% by weight or more based on the entire phosphor-containing composition. More preferably, it is 20% by weight or more, usually 75% by weight or less, preferably 60% by weight or less. If the phosphor content in the phosphor-containing composition is too high, the flowability of the phosphor-containing composition may be inferior and difficult to handle, and if the phosphor content is too low, the light emission efficiency of the light-emitting device decreases. There is a tendency.

  Moreover, you may include other fluorescent substance other than the fluorescent substance concerning this invention as a fluorescent substance contained in a fluorescent substance containing composition. The proportion of the phosphor according to the present invention in the phosphor in the phosphor-containing composition is arbitrary, but is usually 30% by weight or more, preferably 50% by weight or more, and usually 100% by weight or less.

There is no restriction | limiting in particular in fluorescent substance other than the fluorescent substance based on this invention used in a fluorescent substance containing composition. For example, metal oxides typified by Y ₂ O ₃ , YVO ₄ , Zn ₂ SiO ₄ , Y ₃ A ₁₅ O ₁₂ , Sr ₂ SiO _4, etc., which are the base material crystals, typified by Sr ₂ Si ₅ N _8, etc. Metal nitrides, phosphates typified by Ca ₅ (PO ₄ ) ₃ Cl, etc. and sulfides typified by ZnS, SrS, CaS etc., typified by Y ₂ O ₂ S, La ₂ O ₂ S, etc. Ions of rare earth metals such as Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Ag, Cu, Au, Al, Mn, Sb, etc. The thing which combined the ion of metal as an activator element or a coactivator element is mentioned. Table 1 below shows specific examples of preferable host crystals.

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

<Blue phosphor>
When a blue phosphor is used in addition to the phosphor according to the present invention, any blue phosphor can be used as long as the effects of the present invention are not significantly impaired. The phosphors that can be used as the blue phosphor are shown in Table 2 below.

Among these, as the blue phosphor, (Ca, Sr, Ba) MgAl ₁₀ O ₁₇ : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ (Cl, F) ₂ : Eu, (Ba , Ca, Mg, Sr) ₂ SiO ₄ : Eu, (Ba, Ca, Sr) ₃ MgSi ₂ O 8: Eu are preferred, and (Ba, Sr) MgAl ₁₀ O ₁₇ : Eu, (Ca, Sr, Ba) ₁₀ ( PO ₄ ) ₆ (Cl, F) ₂ : Eu and Ba ₃ MgSi ₂ O ₈ : Eu are more preferable, and Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu and BaMgAl ₁₀ O ₁₇ : Eu are particularly preferable.

<Green phosphor>
When using a green phosphor in addition to the phosphor according to the present invention, any green phosphor can be used as long as the effects of the present invention are not significantly impaired. The phosphors that can be used as the green phosphor are shown in Table 3 below.

Among these, as the green phosphor, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, CaSc ₂ O ₄ : Ce, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Sr, Ba) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ : N ₂ : Eu, SrGa ₂ S ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn is preferred. When the light emitting device obtained by using the phosphor according to the present invention is used for an illumination device, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, CaSc ₂ O ₄ : CeCa ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Sr, Ba) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu Is preferred. When the obtained light emitting device is used for an image display device, (Sr, Ba) ₂ SiO ₄ : Eu, (Si, Al) ₆ (O, N) ₈ : Eu (β-sialon), (Ba, Sr) ₃ Si ₆ O ₁₂ N ₂ : Eu, SrGa ₂ S ₄ : Eu, and BaMgAl ₁₀ O ₁₇ : Eu, Mn are preferable.

<Yellow phosphor>
When a yellow phosphor is used in addition to the phosphor according to the present invention, any yellow phosphor can be used as long as the effects of the present invention are not significantly impaired. The phosphors that can be used as the yellow phosphor are shown in Table 4 below.

More in even, as the yellow _{phosphor, Y 3 Al 5 O 12:} Ce, (Y, Gd) 3 A l5 O 12: Ce, (Sr, Ca, Ba, Mg) 2 SiO 4: Eu, (Ca, Sr) Si ₂ N ₂ O ₂ : Eu is preferred.

<Orange to red phosphor>
When an orange or red phosphor is used in addition to the phosphor according to the present invention, any orange or red phosphor can be used as long as the effects of the present invention are not significantly impaired. The phosphors that can be used as orange or red phosphors are shown in Table 5 below.

Among these, as red phosphors, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Ca, Sr, Ba) Si (N, O) ₂ : Eu, (Ca, Sr , Ba) AlSi (N, O) ₃ : Eu, (Sr, Ba) ₃ SiO ₅ : Eu, (Ca, Sr) S: Eu, (La, Y) ₂ O ₂ S: Eu, Eu (dibenzoylmethane) ) Β-diketone Eu complex such as 3,1,10-phenanthroline complex, carboxylic acid Eu complex, K ₂ SiF ₆ : Mn is preferred, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, (Sr, Ca) AlSi (N, O): Eu, (La, Y) ₂ O ₂ S: Eu, and K ₂ SiF ₆ : Mn are more preferable. As the orange phosphor, (Sr, Ba) ₃ SiO ₅ : Eu, (Sr, Ba) ₂ SiO ₄ : Eu, (Ca, Sr, Ba) ₂ Si ₅ (N, O) ₈ : Eu, ( Ca, Sr, Ba) AlSi (N, O) ₃ : Ce is preferred.

  In the phosphor-containing composition, unless the effect of the present invention is significantly impaired, in addition to the phosphor and the liquid medium, other components such as metal oxide for adjusting the refractive index, diffusing agent, filler, viscosity adjustment You may contain additives, such as an agent and a ultraviolet absorber. Only 1 type may be used for another component and it may use 2 or more types together by arbitrary combinations and a ratio.

3.2. Light-emitting device The light-emitting device according to the present invention includes a first light-emitting body and a second light-emitting body that can emit light by converting light from the first light-emitting body into visible light. The body includes the phosphor of the present invention. The emission color of the light-emitting device is not limited to purple or white, and the light-emitting device emits light in any color such as a light bulb color (warm white) or pastel color by appropriately selecting the combination and content of phosphors. Can be manufactured. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

  The light emitting device according to the present invention has a first light emitter as an excitation light source, and the configuration thereof is not limited, except that the second light emitter includes at least the phosphor according to the present invention. A known apparatus configuration can be arbitrarily adopted. A specific example of the device configuration will be described later.

For example, when the light-emitting device according to the present invention is a white light-emitting device, an excitation light source as will be described later is used as the first light emitter, and the phosphor according to the present invention is used as the second light emitter, as described above. A known phosphor such as a phosphor emitting a strong blue fluorescence, a phosphor emitting a green fluorescence, a phosphor emitting a red fluorescence, and a phosphor emitting a yellow fluorescence is used in combination as necessary. What is necessary is just to take an apparatus structure.
Here, the white color of the white light emitting device means all of (yellowish) white, (greenish) white, (blueish) white, (purple) white and white defined by JIS Z 8701 Of these, white is preferred.

3.2.1. First Light Emitter As described above, the phosphor according to the present invention has excellent light emission characteristics when excited with ultraviolet or blue light. Therefore, in order to appropriately excite the phosphor according to the present invention contained in the second luminous body to emit light, the first luminous body emits light having a peak wavelength in a wavelength range of 300 nm or more and 500 nm or less. Is preferred. Among them, those emitting light having a peak wavelength in the near ultraviolet or blue region of 330 nm or more, preferably 360 nm or more, and 480 nm or less, preferably 460 nm or less are preferable.

  Examples of such a first light emitter include a near-ultraviolet light-emitting lamp, a semiconductor light-emitting element that emits ultraviolet to blue light, a semiconductor laser diode (LD), other inorganic electroluminescent elements, and an organic electroluminescent element. Can do. Among them, it is preferable to use a near-ultraviolet LED or a blue LED as the first light emitter.

3.2.2. Second phosphor The second phosphor may be any material as long as it contains at least the phosphor according to the present invention. Any other known phosphor (the blue phosphor, green phosphor, red phosphor, yellow) (Phosphor) may be included. By using these phosphors in appropriate combination, the color tone of the second light emitter can be adjusted. Note that the phosphor-containing composition described above can also be used as the second light emitter.

  As described above, in the light emitting device according to the present invention, the second light emitter includes at least the phosphor according to the present invention. The phosphor according to the present invention, when combined with a first light emitter such as a near-ultraviolet light-emitting lamp or a blue LED, receives light from the first light emitter and emits broad light over a wide wavelength range. be able to. That is, according to the present invention, a light emitting device with high color rendering properties can be provided.

3.2.3. FIG. 1 schematically shows a light emitting device 10 of the present invention according to a first embodiment. As shown in FIG. 1, the light emitting device 10 includes a first light emitter 1 serving as an excitation light source, a second light emitter 2 that emits light upon receiving excitation light from the first light emitter 1, and a substrate 3. ing. An example of the first light emitter used in the first embodiment is a surface-emitting GaN-based LD. In FIG. 1, the wiring of the first light emitter 1 is omitted. The first light emitter 1 is provided so that one surface side is in contact with the second light emitter 2, and the other surface side is bonded to the substrate 3. When the second light emitter 2 is provided on the one surface side of the first light emitter 1, for example, the first light emitter 1 is prepared, and the phosphor-containing composition described above is provided on the one surface side of the first light emitter 1. By applying (injecting) and drying, the second light emitter 2 can be formed on one surface of the first light emitter 1. Alternatively, the first light emitter 1 and the second light emitter 2 may be separately prepared and attached to each other using an adhesive. When the other surface side of the first light emitter 1 is bonded to the substrate 3, it may be bonded using, for example, an adhesive. In addition, as the board | substrate 3, what is normally used as a board | substrate of light-emitting devices, such as resin and a metal, can be used suitably, The shape is not specifically limited, either. When the configuration of the light emitting device 10 is adopted, it is possible to avoid light loss such as light from the first light emitter 1 that is an excitation light source being reflected by the surface of the second light emitter 2 and leaking outside. Therefore, the light emission efficiency of the entire device can be improved.

  FIG. 2 schematically shows the light emitting device 20 of the present invention according to the second embodiment. As shown in FIG. 2, the light emitting device 20 has a configuration generally referred to as a shell type, and includes a first light emitter 11, a second light emitter 12, a mount lead 13, an inner lead 14, and a conductive wire. 15 and a mold member 16.

  FIG. 3 schematically shows a light emitting device 30 according to the third embodiment of the present invention. As shown in FIG. 3, the light emitting device 30 has a configuration generally called a surface mount type, and includes a first light emitter 21, a second light emitter 22, a frame 23, a conductive wire 25, and an electrode. 27 and 28 are provided.

3.3. Application of Light-Emitting Device The application of the light-emitting device according to the present invention is not particularly limited, and can be used in various fields where the light-emitting device is used. In particular, since the light emitting device according to the present invention has high color rendering properties and a wide color reproduction range, it can be suitably used as a light source for an illumination device or an image display device.

3.3.1. Illumination device When the light-emitting device according to the present invention is applied to an illumination device, the above-described light-emitting device may be appropriately incorporated into a known illumination device. For example, a surface emitting illumination device 100 incorporating a plurality of light emitting devices 20 as shown in FIG. The illuminating device 100 is provided with a large number of light emitting devices 20, 20,... On the bottom surface of a rectangular holding case 101 whose inner surface is light-opaque such as a white smooth surface, and the light emitting device is provided on the outside thereof. A power source and a circuit (not shown) for driving 20, 20,... Are provided. In addition, a diffusion plate 102 such as a milky white acrylic plate is provided at a portion corresponding to the lid portion of the holding case 101 for uniform light emission.

  According to the illumination device 100, excitation light is emitted by applying a voltage to the light emitter 1 of the light emitting device 20, and a part of the light emission is absorbed by the light emitter 2, so that the light emitter 2 is diffused to the diffusion plate 102. Visible light is emitted, and illumination light with uniform brightness can be obtained within the surface of the diffusion plate 102. Note that light that has not been absorbed by the light emitter 2 from the light emitter 1 is also emitted to the outside, but rather, it is possible to emit light with high color rendering properties by color mixing.

3.3.2. Image Display Device When the light emitting device according to the present invention is used as a light source of an image display device, the form is not particularly limited, but it is particularly preferable to use it with a color filter. For example, when a color image display device using a color liquid crystal display device is used as the image display device, the light emitting device is used as a backlight, and an optical shutter using liquid crystal is combined with a color filter having red, green, and blue pixels. Thus, an image display device can be configured.

  Hereinafter, the phosphor and the light emitting device according to the present invention will be described in more detail with reference to Examples and Comparative Examples.

<Phosphor>
[Examples 1 to 10, Comparative Examples 1 to 6]
(Raw materials used)
As a raw material compound of the phosphor, CaCO ₃ (manufactured by Kanto Chemical, purity 99.99%), SrCO ₃ (manufactured by Kanto Chemical, purity 99.9%), NH ₄ H ₂ PO ₄ (manufactured by Kanto Chemical, purity 99.99%). 0%), (NH ₄ ) ₃ PO ₄ .3H ₂ O (manufactured by Kanto Chemical Co., Ltd., purity 95.0%) and Eu ₂ O ₃ (manufactured by Mitsuwa Chemical Co., Ltd., high purity, purity 99.99%) were used.

The phosphor sample was synthesized as follows.
CaCO ₃ , SrCO ₃ , NH ₄ H ₂ PO ₄ , (NH ₄ ) ₃ PO ₄ .3H ₂ O, and Eu ₂ O ₃ were weighed as shown in Table 6 below. The weighed raw material compounds were mixed for 10 minutes in an agate mortar, and filled into an alumina boat (length 8 cm, width 1 cm, height 0.8 cm). This was installed in a tubular furnace (manufactured by Asahi Rika Seisakusho). There, a reducing gas was flowed at a flow rate of 1 liter / min. The reducing gas used was an argon base manufactured by Kotobuki Sangyo Co., Ltd. with an H ₂ concentration of 5% by volume. The heating rate was 1400 ° C./40 minutes, and Examples 1 to 2, Examples 4 to 10, Comparative Example 1, and Comparative Examples 4 to 6 were heated at 1400 ° C. (maximum temperature reached) for 2 hours under normal pressure. It was. Then, it cooled at about 2 degree-C / min to 500 degreeC, and took out the sample indoors. The reducing gas continued to flow until the sample was taken out. On the other hand, about Example 3 and Comparative Examples 2-3, the highest ultimate temperature was 1300 degreeC (other baking conditions are Examples 1-2, Examples 4-10, Comparative Example 1, Comparative Examples 4-6. And the same).

  The composition formulas of the phosphors according to Examples 1 to 10 and Comparative Examples 1 to 6 are as shown in Table 7 below. In Table 7, Sr / (Sr + Ca) and Eu / (Ca + Sr) indicate the molar ratio of Sr to the total mole of Sr and Ca, and the molar ratio of Eu to the total mole of Ca and Sr.

<Evaluation of phosphor>
(Emission spectrum, emission intensity, emission peak wavelength)
The emission spectrum was measured using a spectrofluorometer F-4500 (manufactured by Hitachi, Ltd.) at room temperature after putting the phosphor sample in a solid cell. The excitation wavelength was 300 to 450 nm, and the emission wavelength was 400 to 700 nm. The emission intensity and emission peak wavelength were determined from the obtained emission spectrum.

(Chromaticity coordinates)
The chromaticity coordinates are from a 150W xenon lamp using a spectroscope manufactured by Hamamatsu Photonics, irradiating the phosphor sample with light of 405 ± 5 nm through an optical fiber cable, and the light emission location is indicated by a luminance meter BM-5A (Topcon Corporation). The measurement was performed by using The field of view at this time was set to 0.1 °.

(Crystal structure analysis)
Rigaku Multiflex was used for crystal structure analysis. At this time, powder X-ray diffraction was performed using the characteristic X-ray (0.15418 nm) of Cu Kα. The scan speed was 2 ° / min.

<Results and discussion>
(About emission characteristics)
In the case of Sr / Ca = 70/30 (Examples 1-2, Comparative Example 1)
FIG. 5 shows emission spectra when the phosphors according to Examples 1 and 2 and Comparative Example 1 are excited with light having a wavelength of 450 nm.

When Sr / Ca = 2/1 (Example 3, Comparative Examples 2 to 3)
FIG. 6 shows emission spectra when the phosphors according to Example 3 and Comparative Examples 2 to 3 are excited with light having a wavelength of 450 nm. Note that it is considered that the emission intensity was low because the firing temperature was 1300 ° C.

In the case of Sr / Ca = 60/40 (Examples 4 to 7, Comparative Example 4)
FIG. 7 shows emission spectra when the phosphors according to Examples 4 to 7 and Comparative Example 4 are excited with light having a wavelength of 450 nm.

When Sr / Ca = 50/50 (Examples 8 to 9, Comparative Example 5)
FIG. 8 shows emission spectra when the phosphors according to Examples 8 to 9 and Comparative Example 5 are excited with light having a wavelength of 450 nm.

When Sr / Ca = 40/60 (Example 10, Comparative Example 6)
FIG. 9 shows emission spectra when the phosphors according to Example 10 and Comparative Example 6 are excited with light having a wavelength of 450 nm.

  As can be seen from FIGS. 5 to 9, when the Eu concentration p is larger than 0.02, the emission wavelength component near 600 nm is enhanced. That is, a yellow phosphor having a broad emission spectrum from the green region to the orange region was obtained.

  Table 8 below shows the analysis results of the emission spectra of the phosphors according to Examples 1 to 10 and Comparative Examples 1 to 6 when excited with light having a wavelength of 405 nm. Table 9 below shows Examples 1 to 10 and About the fluorescent substance which concerns on Comparative Examples 1-6, the analysis result of the emission spectrum when excited with the light of a wavelength of 450 nm is shown. In Tables 8 and 9, the numerical value related to “arbitrary unit” indicates the value when the emission intensity of the emission spectrum is integrated in the range of 460 nm to 700 nm, and the “area ratio” indicates the values in Examples 1 and 2. Is the value obtained by dividing the integral value of Examples 1 and 2 by the integral value of Comparative Example 1, and for Example 3 and Comparative Example 2, the integral value of Example 3 and Comparative Example 2 is the same as that of Comparative Example 3. For the values divided by the integral value, Examples 4-7, the value obtained by dividing the integral value of Examples 4-7 by the integral value of Comparative Example 4, and for Examples 8, 9, the values of Examples 8, 9 The value obtained by dividing the integral value by the integral value of Comparative Example 5 and Example 10 show values obtained by dividing the integral value of Example 10 by the integral value of Comparative Example 6, respectively. “530/600 intensity ratio” means “ratio of emission intensity at 530 nm to emission intensity at 600 nm” and is calculated from the emission spectrum with respect to the emission intensity (arbitrary unit) at 600 nm calculated from the emission spectrum. The ratio of the emission intensity (arbitrary unit) at 530 nm is calculated.

As is clear from the results shown in Tables 8 and 9, the phosphors according to Examples 1 to 10 are
(1) The chromaticity coordinates (x, y) when excited with light having a peak wavelength of 405 nm are 0.3940 ≦ x ≦ 0.5500, 0.4500 ≦ y ≦ 0.6200,
(2) When excited with light having a wavelength of 450 nm, the ratio of the emission intensity at 530 nm to the emission intensity at 600 nm is 1.26 or less.

(Crystal structure)
The X-ray diffraction patterns of the phosphors of Examples 1 and 2 and Comparative Example 1 were measured. The results are shown in FIG. From FIG. 10, the X-ray diffraction patterns of the phosphors of Example 1, Example 2, and Comparative Example 1 are described in “A. A. Belik et al., Chem. Mater. 14 (2002) 3197-3205”. Β'-Ca _5/7 Sr _16/7 (PO ₄ ) ₂ is considered to belong to the same crystal structure (whitrockite structure type). The X-ray diffraction patterns of other examples and comparative examples also showed similar crystal structures.

<Light emitting device>
[Examples 11 to 12]
A light-emitting device (semiconductor light-emitting device) was manufactured using the phosphors obtained in Example 2 and Example 9 and evaluated as follows.

(Semiconductor light emitting device)
As a semiconductor light-emitting device, one 350-μm square InGaN-based LED chip formed using a sapphire substrate and a main emission peak wavelength of 405 nm is formed on the cavity bottom surface of a 3528 SMD type PPA resin package using a silicone resin-based transparent die-bond paste. Glued to. After bonding, the die bond paste was cured by heating at 150 ° C. for 2 hours, and then the LED chip-side electrode and the package-side electrode were connected using an Au wire having a diameter of 25 μm. Two bonding wires were used.

(Encapsulant)
It was used at a ratio of 100 parts by weight of the curing agent with respect to 100 parts by weight of the main component of the two-pack type silicone resin. Hereinafter, this is referred to as “sealing material liquid”.

(Phosphor)
For Example 11, the phosphor according to Example 9 was used, and for Example 12, the phosphor according to Example 2 was used.

(Phosphor-containing liquid)
A phosphor-containing liquid using the phosphor according to Example 9 was prepared as follows. That is, a phosphor-containing liquid was prepared by adding 33 parts by weight of a phosphor to 100 parts by weight of the sealing material liquid and vacuum-defoaming and mixing at -81 kPa, 1400 rpm for 3 minutes with a vacuum defoaming mixer.
The phosphor-containing liquid using the phosphor according to Example 2 was prepared as follows. That is, a mixture containing 27 parts by weight of a phosphor with respect to 100 parts by weight of the sealing material solution was vacuum defoamed and mixed at -81 kPa, 1400 rpm, 3 minutes with a vacuum defoaming mixer to prepare a phosphor-containing liquid.

(Production of light emitting device)
Using an air dispenser, 4 μL of the phosphor-containing liquid is injected into a semiconductor light-emitting device in which the semiconductor light-emitting element is installed, held at 100 ° C. for 1 hour, and then held at 150 ° C. for 5 hours to cure the formation liquid. A semiconductor light emitting device (white LED) was obtained.

<Evaluation of light emitting device>
(Measurement of emission spectrum and calculation of color rendering index)
Using a fiber multichannel spectrometer (USB2000 manufactured by Ocean Optics (integrated wavelength range: 200 nm to 1100 nm, light receiving method: integrating sphere (diameter: 1.5 inches)) with a current of 20 mA supplied to the semiconductor light emitting device. The color rendering index was calculated using Phoscal 3 manufactured by Mitsubishi Chemical Corporation.

<Results and discussion>
The obtained emission spectra are shown in FIGS. The color rendering index Ra of Example 11 was 81, and the color rendering index Ra of Example 12 was 79. Thus, it was found that the light emitting device using the phosphor according to the present invention exhibits excellent color rendering.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. However, the present invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a phosphor accompanying such a change and a light emitting device using the same are also within the technical scope of the present invention. Must be understood as encompassed by.

  The phosphor according to the present invention can be used for any application using the phosphor, and can be suitably used as a light source of a light emitting device applied to a light source of an illumination device or an image display device.

DESCRIPTION OF SYMBOLS 1 1st light-emitting body 2 2nd light-emitting body 3 Board | substrate 10 Light-emitting device 11 1st light-emitting body 12 2nd light-emitting body 13 Mount lead 14 Inner lead 15 Conductive wire 16 Mold member 20 Light-emitting device 21 1st light emission Body 22 Second light emitter 23 Frame 25 Conductive wire 27 Electrode 28 Electrode 100 Lighting device 101 Holding case 102 Diffusion plate

Claims (5)

A phosphor represented by the following composition formula (1).
M _3-p Eu _p (PO ₄ ) _q (1)
(Here, M is a divalent metal element and contains at least Sr and Ca. Further, p and q satisfy the following formula.
0.02 <p ≦ 0.1
1.6 ≦ q ≦ 2.4) 2. The phosphor according to claim 1, wherein, in the composition formula (1), a molar ratio of Sr to a total mole of Sr and Ca in the M element is 0.2 or more and 0.9 or less. The chromaticity coordinates (x, y) when excited with light having a peak wavelength of 405 nm are
0.3940 ≦ x ≦ 0.5500
0.4500 ≦ y ≦ 0.6200
The phosphor according to claim 1 or 2, wherein The phosphor according to any one of claims 1 to 3, wherein a ratio of emission intensity at 530 nm to emission intensity at 600 nm when excited with light having a wavelength of 450 nm is 1.26 or less. A first light-emitting body and a second light-emitting body capable of emitting light by converting light from the first light-emitting body into visible light, wherein the second light-emitting body includes any one of claims 1 to 4. A light emitting device comprising the phosphor according to claim 1.