JP6372368B2 - Phosphor, light emitting device, lighting device, and image display device - Google Patents

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, the demand for lighting and backlights using LEDs is increasing. 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, a LED using a nitride phosphor that emits red light using blue light from the blue LED chip as an excitation light and a phosphor that emits green light on a blue LED chip has recently been used. It has been.

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.
As green phosphors, phosphors such as nitrides and oxynitrides are attracting attention, and in particular, β-sialon phosphors are being developed.

  For example, Patent Document 1 discloses that the light emission characteristics of a β sialon phosphor are improved by mixing raw materials by a specific method.

JP 2007-145919 A

However, for example, when the phosphor described in Patent Document 1 is used for an LED, the light emission efficiency of the obtained LED may be insufficient, and further improvement of the emission characteristics of the β sialon phosphor is desired.
In view of the above problems, the present inventor has an object to provide a β sialon phosphor that is excellent in light emission characteristics and has good light emission efficiency when used in an LED.

As a result of intensive studies in view of the above problems, the present inventors have found that the light emission efficiency of the obtained LED is improved by using a specific β sialon phosphor, and have reached the present invention. .
That is, the present invention resides in a phosphor represented by the following formula [1] and having a La content of 10 ppm or more and 2000 ppm or less, a light emitting device, a lighting device, and an image display device.

Eu _a Si _b Al _c O _d N _e [1]
(In the above formula [1], a, b, c, d, and e are values satisfying the following ranges, respectively.
0 <a ≦ 0.2
5.6 <b ≦ 5.99
0.01 ≦ c <0.4
0.01 ≦ d <0.4
7.6 <e ≦ 7.99)

  The β sialon phosphor of the present invention is excellent in light emission characteristics, and has good light emission efficiency when used in an LED. Therefore, the light-emitting device including the phosphor of the present invention has good luminous efficiency and excellent color reproducibility. Furthermore, the illumination device and the image display device including the light emitting device of the present invention are of high quality.

2 is a diagram showing an emission spectrum of the phosphor obtained in Example 1. FIG.

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 <x + y < 1) all inclusive It shall be shown.
The present invention relates to a phosphor, a light emitting device, a lighting device, and an image display device. Details will be described below in this order.

<About phosphor>
The β sialon phosphor of the present invention is a phosphor represented by the following formula [1], and has a La content of 10 ppm or more and 2000 ppm or less.

Eu _a Si _b Al _c O _d N _e [1]
(In the above formula [1], a, b, c, d, and e are values satisfying the following ranges, respectively.
0 <a ≦ 0.2
5.6 <b ≦ 5.99
0.01 ≦ c <0.4
0.01 ≦ d <0.4
7.6 <e ≦ 7.99)
In the formula [1], Eu represents europium. Eu is partially activated by other elements such as manganese (Mn), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium ( It may be activated by Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or the like.

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], 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). ) And the like may be partially substituted.

In the formula [1], O represents an oxygen element, and N represents a nitrogen element. O or N may partially contain other elements such as halogen atoms (fluorine (F), chlorine (Cl), bromine (Br), iodine (I)) and the like.
In addition, halogen atoms may be mixed as impurities in the raw material metal or introduced during the manufacturing process such as pulverization process, nitriding process, etc. Especially when halide is used as flux, it is included in the phosphor. There is a case that it will be.

a represents the content of Eu, the range is usually 0 <a ≦ 0.2, the lower limit is preferably 0.0001, more preferably 0.001, and the upper limit is preferably 0.15, more preferably 0.1, particularly preferably 0.08.
b represents the content of Si, and the range is usually 5.6 <b ≦ 5.99, the lower limit is preferably 5.7, and the upper limit is preferably 5.97. .

c represents the content of Al, the range is usually 0.01 ≦ c <0.4, the lower limit is preferably 0.03, and the upper limit is preferably 0.3.
d represents the content of O, the range is usually 0.01 ≦ d <0.4, the lower limit is preferably 0.03, and the upper limit is preferably 0.3.
e represents the content of N, and the range thereof is usually 7.6 <e ≦ 7.99, the lower limit value is preferably 7.7, and the upper limit value is preferably 7.77.

Any content is within the above-described range, which is preferable in terms of good light emission characteristics of the obtained phosphor.
The phosphor of the present invention contains La. The La content is usually 10 ppm or more and 2000 ppm or less, and the upper limit is preferably 1500 ppm or less, more preferably 1000 ppm or less.
It is preferable that it is within the above-mentioned range from the viewpoint that the emission luminance of the obtained phosphor is good.

<Physical properties of phosphor>
[Peak emission wavelength]
The β sialon phosphor of the present invention is excited by light having a wavelength of 300 nm or more and 500 nm or less, its emission peak wavelength is usually 500 nm or more and 560 nm or less, and the lower limit is preferably 510 nm or more, preferably 520 nm or more, and the upper limit is preferably 550 nm or less.

<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 Si raw material (hereinafter referred to as “Si source” as appropriate). ), An Al raw material (hereinafter referred to as “Al source” as appropriate) is mixed (mixing step), and the resultant mixture is fired (firing 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]
As the phosphor raw material used for producing the phosphor of the present invention, known materials can be used, for example, silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), silicon oxide (SiO ₂ ). ) And / or aluminum oxide (Al ₂ O ₃ ), and Eu compounds selected from metals, oxides, carbonates, chlorides, fluorides, nitrides, or oxynitrides of Eu. Moreover, although Si metal can be used as the Si source, it is preferable to use silicon nitride (Si ₃ N ₄ ) in the present invention because the oxygen concentration contained in the phosphor tends to decrease.

  Note that O (oxygen) and N (nitrogen) in the formula [1] may be supplied from a Si source, an Al source, and a Eu source, and N (nitrogen) may be supplied from a firing atmosphere. Each raw material may contain inevitable impurities.

(Mixing process)
The phosphor raw materials are weighed so that the target composition can be obtained, and thoroughly mixed using a ball mill or the like to obtain a phosphor raw material mixture (mixing step). In the present invention, it is preferable to mix sufficiently so that each constituent element (especially, Eu as an activating element) is uniformly distributed.
As described above, Eu is collapses the balance of charge as a solid solution in the crystal, by a +2 content of Eu Si and Al, believed to balance the charge of the entire crystal, Si ⁴⁺ 2 When the number of Al3 + is decreased and the number of Al3 + is increased, the total number is -2, which is considered to correspond to the solid solution of Eu2 ⁺ . Considering this, it is preferable that Al and Eu are present in the vicinity in the phosphor raw material mixture, and Al ³⁺ and Eu ²⁺ are present in the vicinity when they are dissolved in the crystal.

When mixed sufficiently, Eu is uniformly distributed in the phosphor raw material mixture, so that the deviation of Al and Eu is reduced, and Eu ²⁺ and Al are uniformly distributed during firing. It is considered that when Eu is dissolved in the form of Eu ²⁺ , the balance of charges in the crystal is easily maintained, and the luminance is improved.
On the other hand, in the case of non-uniform mixing where the Al compound does not exist near Eu but is biased, Al does not reach the vicinity of Eu even during ion diffusion during firing, and the charge balance cannot be maintained. it is conceivable that. If the charge balance is not maintained, since hardly dissolved in the crystal in the form of Eu 2 ⁺ ions, the absorption efficiency of the excitation light, such as light-emitting luminance is practically provided in the light emitting device phosphor There is a tendency that the light emission characteristics required at this time are lowered. On the other hand, a phosphor containing a crystal with a balanced charge is chemically more stable and becomes a phosphor excellent in emission characteristics.

Although the method of the said mixing is not specifically limited, Specifically, the following methods (A) and (B) are mentioned.
(A) Dry pulverizers such as hammer mill, roll mill, ball mill, jet mill, vibration mill, etc., or pulverizers using mortar and pestle and mixers such as ribbon blender, V-type blender, Henschel mixer, rocking mixer, etc. Alternatively, a dry mixing method in which the above-described phosphor raw materials are pulverized and mixed by combining mortar and mixing using a pestle.
(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, and Examples include a method in which a stable phosphor raw material component in water is first wet mixed in a water-soluble solvent and dried, and then an unstable raw material component is added in water and mixed dry. .
In order to sufficiently mix the phosphor raw materials, in the case of mixing by the method (A), it is preferable to mix for at least 60 minutes, more preferably 90 minutes or more, and 120 minutes or more. More preferably, they are mixed. Moreover, it is preferable to mix by the mixing method of two steps, mixing and grinding | pulverization. In the case of mixing by the method (B), it is preferable to mix for at least 60 minutes in the state of a solution or slurry. In addition, in order to mix Eu as an activation element well in the raw material, for example, a water-soluble Eu compound such as carbonate, nitrate, sulfate, chloride is dissolved in water, and then other phosphors A method of mixing with the raw material is preferred.

(Baking process)
The raw material mixture obtained in the mixing step is fired (firing step). The above phosphor raw material mixture is dried, if necessary, and then filled in a container such as a crucible having at least the surface in contact with the raw material made of boron nitride, and fired using a firing furnace, a pressure furnace, or the like.
Since the firing temperature varies depending on the desired phosphor composition, it cannot be defined in general, but in general, the phosphor can be stably obtained in a temperature range of 1820 ° C. or higher and 2200 ° C. or lower. If the firing temperature is 1820 ° C. or higher, Eu can enter the β sialon crystal, and a phosphor having sufficient luminance can be obtained. Further, if the heating temperature is 2200 ° C. or less, it is not necessary to suppress the decomposition of β sialon by applying a very high nitrogen pressure, and therefore, a special apparatus is not required, which is industrially preferable.

  A preferable firing temperature is preferably 1850 ° C. or higher, particularly preferably 1900 ° C. or higher, more preferably 2200 ° C. or lower, and particularly preferably 2100 ° C. or lower. The firing atmosphere in the firing step is arbitrary as long as the phosphor of the present invention is obtained, but is usually a nitrogen-containing atmosphere. 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 rate of temperature rise is usually 2 ° C./min or more, preferably 3 ° C./min or more, and usually 10 ° C./min or less, preferably 5 ° C./min or less. It is preferable that the rate of temperature increase be in the above-mentioned range because it is possible to avoid an excessively long firing time.
The firing time varies depending on the firing temperature, pressure, etc., but is usually 10 minutes or longer, preferably 1 hour or longer, and usually 24 hours or shorter, preferably 12 hours or shorter. The pressure during firing varies depending on the firing temperature or the like, but is usually 0.1 MPa or more, preferably 0.5 MPa or more, and the upper limit is usually 2.0 MPa or less, preferably 1.5 MPa or less. Among these, 0.6 MPa or more and 1.2 MPa or less are industrially preferable in terms of cost and labor.

The obtained fired product is granular or massive. This is pulverized, pulverized and / or classified into a powder of a predetermined size. Here, the processing may be performed 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.

(Heat treatment process)
In order to produce the phosphor of the present invention, it is preferable to further heat-treat the phosphor obtained in the firing step (heat treatment step). This is because the impurity phase of oxynitride is thermally decomposed. When the heat treatment process is performed, ions such as Eu distributed unevenly in the phosphor are easily diffused, and the thermal decomposition of the impurity phase formed on the surface of the phosphor during the firing process is promoted. Can be improved.

An appropriate heat treatment temperature in the heat treatment step varies depending on the atmosphere or the like, but a temperature range of 1200 ° C. or higher and 1550 ° C. or lower is preferable. The decomposition of the impurity phase tends to proceed at 1200 ° C. or higher, and the rapid decomposition of β sialon can be suppressed at 1550 ° C. or lower.
Examples of the heat treatment atmosphere include a nitrogen atmosphere, a hydrogen-containing nitrogen atmosphere, an argon atmosphere, a hydrogen-containing argon atmosphere, and a vacuum atmosphere, and an argon atmosphere is preferable.

The pressure during the heat treatment varies depending on the heat treatment temperature and the like, but is usually 0.09 MPa or more, preferably 0.1 MPa or more, and the upper limit is usually 1 MPa or less, preferably 0.5 MPa or less.
The heat treatment time varies depending on the temperature and pressure during the heat treatment, but is usually 10 minutes or longer, preferably 1 hour or longer, and usually 24 hours or shorter, preferably 12 hours or shorter.
In addition, although a baking process and a heat processing process may be performed continuously at the time of the cooling after the heating in the above-mentioned baking process, it is more effective to heat-treat after adjusting to a predetermined particle size. This is because not only crystal defects formed during firing but also crystal defects formed during crushing and pulverization can be removed.

In addition, when manufacturing the fluorescent substance of this embodiment, it is preferable to use LaN as a flux (crystal growth adjuvant) at the time of the said baking process, for example.
Further, as the flux, LaN, AlF ₃ , LaF ₃ or the like may be used in combination with LaN.

(Washing process)
In the β sialon phosphor, Si metal tends to be generated on the phosphor surface by thermal decomposition in a firing step or a heat treatment step. Therefore, in order to improve the characteristics of the phosphor, it is preferable to remove and reduce this Si metal as much as possible. Therefore, it is preferable to provide a cleaning step after the firing step and the heat treatment step. By the cleaning process, it is possible to remove and reduce Si metal or impurity phase other than Si metal generated on the surface of the phosphor in the firing process or heat treatment process. Thereby, the component which absorbs the light emission from fluorescent substance reduces, and there exists an effect that a light emission characteristic improves. In the present invention, the cleaning method is not particularly limited as long as impurities can be removed and reduced. For example, cleaning can be performed using hydrofluoric acid and nitric acid.

Here, while it is immersed in the aqueous solution, it may be left standing, but from the viewpoint of work efficiency, it is preferable to stir to such an extent that the cleaning time can be shortened. Moreover, although work | work is normally performed at room temperature (about 25 degreeC), you may heat aqueous solution as needed.
Although the time for immersing the phosphor varies depending on the stirring conditions and the like, it is usually 1 hour or longer, preferably 2 hours or longer, and usually 24 hours or shorter, preferably 12 hours or shorter.

[Use of phosphor]
The β sialon phosphor of the present invention can be used for any application using a phosphor. In addition, the phosphor of the present invention can be used alone, but two or more of the phosphors of the present invention can be used together, or the phosphor of the present invention and other phosphors It is also possible to use as a phosphor mixture of any combination.

The phosphor of the present invention can be used as a phosphor-containing composition by mixing with a known liquid medium (for example, a silicone compound).
In addition, the phosphor of the present invention is suitably used for various light-emitting devices by combining with a light source that emits near-ultraviolet light or blue light, taking advantage of the fact that it can be excited by near-ultraviolet light or blue light. be able to. Since the phosphor of the present invention is usually a green light emitting phosphor, for example, when an excitation light source that emits blue light is combined with the phosphor of the present invention, a blue to green light emitting device can be manufactured. In addition, the phosphor of the present invention is combined with an excitation light source that emits blue light and a phosphor that emits red light, or an excitation light source that emits near-ultraviolet light, a phosphor that emits blue light, and a fluorescence that emits red light. If the bodies are combined, the phosphor of the present invention emits green light, and thus a white light emitting device can be manufactured.

  The emission color of the light-emitting device is not limited to white, and by appropriately selecting the combination and content of phosphors, a light-emitting device that emits light in any color such as light bulb color (warm white) or pastel color is manufactured. can do. The light-emitting device thus obtained can be used as a light-emitting portion (particularly a liquid crystal backlight) or an illumination device of an image display device.

<Phosphor-containing composition>
The phosphor of the present invention can be used by mixing with a liquid medium. In particular, when the phosphor of the present invention is used for applications such as a light emitting device, it is preferably used in a form dispersed in a liquid medium. A dispersion of the phosphor of the present invention in a liquid medium is appropriately referred to as “the phosphor-containing composition of the present invention” as an embodiment of the present invention.

[Phosphor]
There is no restriction | limiting in the kind of fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention, It can select arbitrarily from what was mentioned above. Moreover, the fluorescent substance of this invention contained in the fluorescent substance containing composition of this invention may be only 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Furthermore, you may make the fluorescent substance containing composition of this invention contain fluorescent substances other than the fluorescent substance of this invention, unless the effect of this embodiment is impaired remarkably.

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

[Content of liquid medium and phosphor]
The content of the phosphor and the liquid medium in the phosphor-containing composition of the present invention is arbitrary as long as the effects of the present embodiment are not significantly impaired, but the liquid medium is included in the entire phosphor-containing composition of the present invention. On the other hand, it 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 invention 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 light-emitting device of the present invention is a light-emitting device that includes a first light-emitting body (excitation light source) and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body. The phosphor of the present invention is contained as the first phosphor in the second light emitter. Here, any one of the phosphors of the present invention may be used alone, or two or more thereof may be used in any combination and ratio.

As the β sialon phosphor of the present invention, for example, a phosphor that emits fluorescence in the green region under irradiation of light from an excitation light source is used. Specifically, in the case of constituting a light emitting device, the β sialon phosphor in the first embodiment of the present invention preferably has a light emission peak in a wavelength range of 500 nm or more and 560 nm or less.
Hereinafter, a light-emitting device in which the phosphor of the present invention has a light emission peak in a wavelength range of 500 nm to 560 nm and a first light emitter has a light emission peak in a wavelength range of 300 nm to 500 nm. However, the present embodiment is not limited to these.

In the above case, the light emitting device of the present invention can be set, for example, as follows.
That is, as the first light emitter, one having a light emission peak in the wavelength range of 300 nm to 500 nm is used, and as the second phosphor of the second light emitter, the light emission peak is present in the wavelength range of 500 nm to 560 nm. At least one kind of phosphor (the phosphor of the present invention) and a phosphor having a light emission peak in the wavelength range of 580 nm to 680 nm (red phosphor) can be used.

(Red phosphor)
As a red fluorescent substance in said aspect, the following fluorescent substance is used suitably, for example.
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 the fluorescent substance (yellow fluorescent substance) which has the light emission peak of the range of 550-580 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 the present invention has a first light emitter (excitation light source), and at least the phosphor of the present invention is used as the second light emitter. It is possible to arbitrarily adopt the apparatus configuration.
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 light-emitting device of the present invention is not particularly limited and can be used in various fields in which ordinary light-emitting devices are used, but has a wide color reproduction range and high color rendering properties. Therefore, it is particularly preferably used as a light source for an illumination device or an image display device.

[Lighting device]
The illumination device of the present invention includes the light emitting device of the present invention as a light source.
When the light-emitting device of the present invention is applied to a lighting device, the above-described light-emitting device may be appropriately incorporated into a known lighting device. For example, 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]
The image display device of the present invention includes the light emitting device of the present invention as a light source.
When the light emitting device of the present invention is used as a light source of an image display device, the specific configuration of the image display device is not limited, but it is preferably used together 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.

[Relative brightness]
The relative luminance is a sample of Comparative Example 1 from the stimulation value Y in the XYZ color system calculated based on JIS Z8701 based on the data in the wavelength region of 480 nm to 800 nm (when excitation wavelength is 455 nm) of the emission spectrum. Relative value (hereinafter, referred to as 100%)
It may be simply referred to as “luminance”. ).

[Chromaticity coordinates]
The chromaticity coordinates of the x, y color system (CIE 1931 color system) are the chromaticity coordinates in the XYZ color system defined in JIS Z8701- from the data of the wavelength region excluding the excitation wavelength region of the emission spectrum. Calculated as CIEx and CIEy.

[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. In the analysis of the metal elements (Si, Al, Eu) that were formed, the measurement was performed by inductively coupled plasma emission spectroscopy (ICP-AES). ICPS-8100 (manufactured by Shimadzu Corporation) was used as a measuring device.
EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded.

[Examples 1 to 5]
α-type silicon nitride powder “SN-E10” grade (manufactured by Ube Industries), aluminum nitride powder “E” grade (manufactured by Tokuyama), europium oxide powder “RU” grade (manufactured by Shin-Etsu Chemical Co., Ltd.), lanthanum oxide powder ( (Shin-Etsu Chemical Co., Ltd.) was weighed so as to have the blended amount shown in Table 1 and mixed until it was sufficiently uniform.

The obtained raw material mixture was filled in 300 g of a boron nitride crucible having an outer diameter of 9 cm and a height of 10 cm, fired by holding at 2025 ° C. for 18 hours under an atmosphere of nitrogen pressure of 0.95 MPa, and then argon pressure of 0 In a 205 MPa atmosphere, heat treatment was performed by holding at 1450 ° C. for 12 hours, and a nylon mesh (NMG23, mesh opening: 900 μm) was passed to obtain heat treated powder. The obtained heat-treated powder was washed and dried to obtain phosphors of Examples 1 to 5. When the phosphor of Example 1 obtained at this time was analyzed by ICP-AES, the concentration of La in the phosphor was 761 ppm. From this, it can be seen that the La content in the phosphor is about half of the charged amount. That is, about the phosphor obtained in Examples 2 to 5, about half of the charged amount is similarly contained in the phosphor.
In addition, Table 2 shows the results of measuring the emission characteristics of the phosphors obtained in Examples 1 to 5. The relative luminance is a value when the phosphor obtained in Comparative Example 1 described later is 100%.

[Comparative Example 1]
The phosphor of Comparative Example 1 was obtained through the same process as Example 1 except that the lanthanum oxide powder was not included in the raw material mixing process.

  As shown in Table 2, it can be seen that the phosphor of the present invention has high emission luminance. Accordingly, 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.

Claims (5)

A phosphor represented by the following formula [1],
A β-sialon phosphor having a La content of 10 ppm or more and 2000 ppm or less.

Eu _a Si _b Al _c O _d N _e [1]

(In the above formula [1], a, b, c, d, and e are values satisfying the following ranges, respectively.
0 <a ≦ 0.2
5.6 <b ≦ 5.99
0.01 ≦ c <0.4
0.01 ≦ d <0.4
7.6 <e ≦ 7.99)   The β sialon phosphor according to claim 1, wherein the β sialon phosphor has a light emission peak in a wavelength range of 500 nm or more and 560 nm or less by irradiation with excitation light having a wavelength of 300 nm or more and 500 nm or less.   A first light emitter and a second light emitter that emits visible light when irradiated with light from the first light emitter, wherein the second light emitter is the phosphor according to claim 1. A light emitting device characterized by the above.   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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