JP4843990B2 - Phosphor and light emitting device using the same - Google Patents

Description

  The present invention relates to a light emitting device used for electrical decoration, a display, a backlight light source, a display, an illuminated switch, various indicators, and the like, and a phosphor usable for the same.

  A light emitting device capable of emitting white color mixed light by combining a light emitting element formed of a gallium nitride compound semiconductor and a fluorescent material has been developed. This light-emitting device converts a part of blue light output from a light-emitting element with a fluorescent material, and mixes the wavelength-converted light with blue light from a light-emitting element chip, thereby producing a white color mixture. It emits light.

As a photoluminescent phosphor suitable for use in combination with such a gallium nitride based semiconductor light emitting device,
1. Because it is exposed to strong light from the light emitting element, it has excellent light resistance without being deteriorated for a long time against irradiation of such strong light.
2. Since it is excited by the light emitting element, it emits light efficiently by the light emitting element. In particular, when using mixed colors, emit light efficiently with blue light, not ultraviolet light.
3. It must be capable of emitting green, yellow or red light so that it is mixed with blue light to give a white color tone.
4). Good temperature characteristics because it is affected by temperature changes due to heat generation when the chip emits light near the light emitting element.
5). The color tone can be continuously changed by changing the composition ratio or the mixing ratio of a plurality of phosphors.
6). Characteristics such as weather resistance according to the environment in which the light emitting diode is used are required. Examples of the phosphor satisfying such characteristics include a phosphor having a garnet structure as disclosed in International Publication No. WO 98/5078, for example, an yttrium aluminum garnet phosphor.

  Furthermore, a light emitting device using a semiconductor light emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode) as described above has the following excellent characteristics. (1) Small size, high power efficiency and bright color emission. (2) Since it is a semiconductor element, there is no worry about a broken ball. (3) Excellent initial drive characteristics and strong against vibration and repeated on / off lighting.

  Because of such excellent characteristics, the above-described light-emitting device is used in a wide range of fields such as indoor lighting, in-vehicle lighting, displays, and backlights for liquid crystals.

WO 98/5078 publication.

  In the future, various optical devices using the above-described light emitting device can be considered. For example, it is an electrical decoration in which the luminance of light emitted from the light emitting device is different for each predetermined region.

  However, it is not easy for the above-described light emitting device to vary the light emission luminance for each predetermined region while keeping the color tone substantially constant. For example, a light-emitting device including a plurality of light-emitting elements and yttrium, aluminum, and garnet phosphors having the same composition disposed in each of the light-emitting elements is provided. Further, by supplying different amounts of power for each of the plurality of light emitting elements, the luminance is changed for each predetermined region while keeping the color tone of the mixed color light substantially constant. Such a light-emitting device requires a driving device that controls the power supplied to each light-emitting element, and the configuration of the light-emitting device is also complicated overall.

  In addition, the phosphor combined with the gallium nitride-based light-emitting element is preferably a phosphor having a garnet structure with excellent emission characteristics, such as the yttrium-aluminum-garnet-based phosphor described above. Further, such a phosphor needs to be efficiently excited even by light in the blue region, and the light emission luminance needs to be improved.

  Therefore, as a phosphor that can be used in a light-emitting device, a phosphor having a light emission luminance different from that of an yttrium / aluminum / garnet phosphor is required without changing the basic characteristics of the yttrium / aluminum / garnet phosphor. That is, an object of the present invention is to provide a phosphor capable of simplifying the configuration of a light-emitting device that changes the emission luminance step by step for each predetermined region.

  The present invention is a phosphor having a general formula represented by the following formula.

_{(Ln 1-x-y,} Y x, Ce y) 3 (A 1-m-n, Sc m, Ga n) 5 O 12
Here, Ln represents at least one element selected from the group consisting of Gd and Tb, A represents at least one element selected from the group consisting of Al and In, and x, y, m, and n are as follows: Satisfies the numerical value of
0 ≦ x ≦ 0.6
0.0001 ≦ y ≦ 0.3
0.1 ≦ m ≦ 0.9
0 ≦ n ≦ 0.5
Further, the present invention provides a light-emitting device including a light-emitting element and a fluorescent material that emits light having a different wavelength by absorbing at least part of the light of the light-emitting element, wherein the fluorescent material is represented by the general formula. A light emitting device characterized by being a phosphor.

  In addition, the fluorescent material includes rare earth aluminate phosphor, alkaline earth silicate phosphor, alkaline earth halogen apatite phosphor, alkaline earth borate halogen phosphor, alkaline earth aluminate, rare earth acid It is preferable to have at least one phosphor selected from sulfide phosphors, nitride phosphors, oxynitride phosphors, or organic complex phosphors. Thereby, it can be set as the light-emitting device which has various chromaticity and brightness | luminance.

  The phosphor of the present invention can be a phosphor with the emission luminance changed, while maintaining the basic characteristics of the aluminum garnet phosphor as described above. That is, the phosphor according to the present invention is a phosphor with little deterioration in optical characteristics even when combined with a nitride semiconductor light emitting device. Furthermore, the phosphor according to the present invention can have a light emission luminance lower than that of the yttrium / aluminum / garnet phosphor. Therefore, the phosphor according to the present invention can be combined with a light emitting device including an yttrium / aluminum / garnet-based phosphor to produce an illuminating device in which the intensity of light emission is changed for each predetermined observation region, or high luminance light emission. It can also be applied as a phosphor for an inexpensive light-emitting device that is not planned.

  In addition, the phosphor according to the present invention is obtained by moving the excitation wavelength and the emission wavelength in the short wavelength direction by partially replacing aluminum, which is one of the constituent elements of the rare earth aluminate phosphor, with scandium. . Therefore, the phosphor according to the present invention can be efficiently excited by a light emitting element having a peak wavelength of emission intensity on the short wavelength side, and can be a light emitting device with high wavelength conversion efficiency.

  In addition, the light emitting device according to the present invention does not require a driving device for controlling the power supplied to each light emitting element, and the intensity of light emission is increased step by step with a simpler configuration. It can be used as a changed lighting device.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light emitting device for embodying the technical idea of the present invention, and the present invention does not limit the light emitting device to the following.

  Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In this specification, JIS Z8110 is taken into consideration for the relationship between the color name and the chromaticity coordinates.

  In order to solve the above-described problems, the phosphor according to the present invention includes (a) at least one selected from the group consisting of gadolinium and terbium, and (b) at least one selected from the group consisting of aluminum, indium and gallium. And (c) a rare earth aluminate phosphor having scandium. Furthermore, the rare earth aluminate phosphor according to the present invention preferably has (d) gallium or yttrium.

  More specifically, the present invention is a phosphor characterized in that the general formula is represented by the following formula.

_{(Ln 1-x-y,} Y x, Ce y) 3 (A 1-m-n, Sc m, Ga n) 5 O 12
Here, Ln represents at least one element selected from the group consisting of Gd and Tb, A represents at least one element selected from the group consisting of Al and In, and x, y, m, and n are as follows: Satisfies the numerical value of
0 ≦ x ≦ 0.6
0.0001 ≦ y ≦ 0.3
0.1 ≦ m ≦ 0.9
0 ≦ n ≦ 0.5
In order to solve the above-described problem in a light-emitting device including a light-emitting element and a fluorescent material that absorbs part of light of the light-emitting element and emits light having a different wavelength, the present invention provides It is represented by the above general formula.

  In the present invention, the fluorescent substance may be a rare earth aluminate-based phosphor, an alkaline earth silicate phosphor, an alkaline earth halogen apatite phosphor, an alkaline earth borate phosphor, an alkaline earth aluminate. And at least one phosphor selected from rare earth oxysulfide phosphors, nitride phosphors, oxynitride phosphors, and organic complex phosphors. Thereby, it can be set as the light-emitting device from which a color tone and a brightness | luminance differ for every predetermined area | region.

  Furthermore, it is set as the illuminating device which has the light-emitting device provided with the fluorescent substance represented by the said general formula, and the light-emitting device provided with at least 1 type of fluorescent substance selected from these fluorescent substances.

  Thereby, it can be set as the light-emitting device from which color tone and brightness differ for every light-emitting device. In particular, the phosphor according to the present invention can be used in a lighting device in which the color tone is substantially constant and the luminance is different for each light-emitting device when combined with a light-emitting device including an yttrium, aluminum, and garnet phosphor. Hereafter, each structure of this invention is explained in full detail.

[Fluorescent substance]
The fluorescent substance in the light emitting device according to this embodiment absorbs part of visible light and ultraviolet light emitted from the light emitting element, and emits light having a wavelength different from the wavelength of the absorbed light. In particular, the phosphor used in this embodiment refers to a phosphor that emits a wavelength-converted light that is excited by at least light emitted from the light-emitting element, and constitutes a wavelength conversion member together with a binder that fixes the phosphor. To do.

  The fluorescent substance in this embodiment can be made into a wavelength conversion member by binding with various binders (binders) such as an organic material resin or an inorganic material glass. For example, when an organic material is used as the binder, a translucent resin such as an epoxy resin, an acrylic resin, or a silicone resin is preferably used as a specific material. In particular, a silicone resin is preferable because it is excellent in light resistance and can improve dispersibility of a fluorescent substance.

  A binder mainly composed of an inorganic material is preferable because it has little absorption with respect to radiation in the ultraviolet to visible region and is extremely stable in the wavelength conversion member. As a specific method of forming an inorganic substance as a binder and a wavelength conversion member, a precipitation method, a sol-gel method, or the like can be used. For example, a fluorescent material, a metal alkoxide, and ethanol are mixed to form a slurry, and the slurry is discharged from a nozzle, and then heated at 300 ° C. for 3 hours to fix the fluorescent material to a desired location. .

  When the light emitted from the light-emitting element and the light emitted from the phosphor are in a complementary color relationship or the like, white mixed color light can be emitted by mixing each light. Specifically, the light emitted from the light emitting element and the phosphor light excited and emitted thereby correspond to the three primary colors of light (red, green, and blue), or the blue light emitted from the light emitting element. And yellow light of a phosphor that is excited to emit light.

  The emission color of the light emitting device can be adjusted by variously adjusting the ratio of the phosphor and the binder of the phosphor, the specific gravity of the phosphor, the amount and shape of the phosphor, and the light emission wavelength of the light emitting element. The color temperature of the mixed color light can be changed to provide an arbitrary white color tone such as a light bulb color region.

Since such a phosphor settles under its own weight in the gas phase or liquid phase, it is dispersed and uniformly released in the gas phase or liquid phase, and in particular in the liquid phase, the suspension is allowed to stand, A layer having a phosphor with higher uniformity can be formed. Furthermore, a desired phosphor amount can be formed by repeating a plurality of times as desired.
Two or more kinds of phosphors formed as described above may be present in a single-layer wavelength conversion member on the surface of the light-emitting device, or one or two of each of the two-layer wavelength conversion member. There may be more than one type. In this way, white light can be obtained by mixing colors from different types of phosphors. In this case, it is preferable that the average particle diameters and shapes of the phosphors are similar in order to better mix the light emitted from the phosphors and reduce color unevenness.

  Here, the particle size in the present specification is a value obtained from a volume-based particle size distribution curve. The volume-based particle size distribution curve is obtained by measuring the particle size distribution by a laser diffraction / scattering method, and specifically, hexametaphosphoric acid having a concentration of 0.05% in an environment of an air temperature of 25 ° C. and a humidity of 70%. Each substance was dispersed in an aqueous sodium solution and measured with a laser diffraction particle size distribution analyzer (SALD-2000A) in a particle size range of 0.03 μm to 700 μm. In this volume-based particle size distribution curve, it is a particle size value when the integrated value is 50%, and the central particle size of the fluorescent material used in the present invention is preferably in the range of 5 μm to 50 μm. Moreover, it is preferable that the fluorescent substance which has this center particle size value is contained frequently, and the frequency value is preferably 20% to 50%. In this way, by using a fluorescent material with small variation in particle size, a light emitting device having a favorable color tone with more suppressed color unevenness can be obtained. Hereinafter, each phosphor will be described in detail.

(Rare earth aluminate phosphor)
The phosphor according to the present invention includes (a) at least one element selected from the group consisting of gadolinium and terbium; (b) at least one element selected from the group consisting of aluminum, indium and gallium; ) Scandium, and a rare earth aluminate phosphor. Furthermore, the rare earth aluminate phosphor according to the present invention has (d) yttrium as necessary. That is, the general formula of the rare earth aluminate phosphor according to the present invention can be expressed by the following formula.
_{(Ln 1-x-y,} Y x, Ce y) 3 (A 1-m-n, Sc m, Ga n) 5 O 12
Here, Ln represents at least one element selected from the group consisting of Gd and Tb, A represents at least one element selected from the group consisting of Al and In, and x, y, m, and n are the following: Satisfy the numerical value. Thereby, the brightness | luminance of the rare earth aluminate fluorescent substance concerning this invention can be improved.
0 ≦ x ≦ 0.6
0.0001 ≦ y ≦ 0.3
0.1 ≦ m ≦ 0.9
0 ≦ n ≦ 0.5
In particular, when x = 0, n = 0, Ln = Gd, and A = Al, the above general formula can be expressed by the following formula.
_{(Gd 1-y, Ce y} ) 3 (Al 1-m, Sc m) 5 O 12
Specific composition formula of such a rare-earth aluminate phosphor, for _{example, Gd 2.85 Ce 0.15 ScAl 4 O} 12, Gd 2.85 Ce 0.15 Sc 2 Al 3 O 12, Gd 2.85 Mention may be made of Ce _0.15 Sc ₃ Al ₂ O ₁₂ , Gd _2.85 Ce _0.15 Sc ₄ AlO ₁₂ . As a comparative example of the rare earth aluminate phosphor according to the present embodiment, it includes a phosphor having a composition formula of _Gd 2.85 _Ce 0.15 _Al 5 _{O 12} as a comparative example 1.

Table 1 below shows the emission characteristics of these rare earth aluminate phosphors. Here, the emission characteristics of Examples 1 to 4 and Comparative Example 1 shown in Table 1 are the chromaticity coordinate values (x, y) and the relative values of the luminous flux (when the phosphor is excited by light of 460 nm). %). 3 to 7 show emission spectra when the phosphors of Examples 1 to 4 and Comparative Example 1 are excited by light of 460 nm, respectively. The luminous flux and emission spectrum of each phosphor are obtained by exciting a phosphor represented by the composition formula Gd _0.6 Ce _0.03 Y _2.4 Al ₅ O ₁₂ (referred to as Comparative Example 2) with light of 460 nm. This is compared with the luminous flux and the emission spectrum (FIG. 8).

As shown in Table 1, the rare earth aluminate phosphor of Example 4 from the first embodiment, a rare earth aluminate Comparative Example 1 in which the composition formula is represented by _Gd 2.85 _Ce 0.15 _Al 5 _{O 12} Of the elements constituting the phosphor, it can be considered that a part of Al is replaced with Sc. As described above, the phosphor according to the present invention can improve the light emission luminance of the rare earth aluminate phosphor having a relatively small light emission luminance as in Comparative Example 1 by replacing a part of Al with Sc. it can. Here, the ratio of Al being replaced by Sc is preferably 0.5 to 0.7. This is because, in the rare earth aluminate phosphor, if the ratio of Al substituted with Sc becomes too high, the emission luminance is remarkably lowered. Further, the composition in which Al is replaced with Sc is more preferably about 0.6. This is because the emission luminance of the rare earth aluminate phosphor according to the present invention can be increased.

  The rare earth aluminate phosphor according to the present invention is a phosphor having an emission spectrum having a main peak wavelength in the range of 510 nm to 580 nm and an excitation spectrum having a main peak wavelength in the visible range of 430 nm to 470 nm. Further, according to the first to fourth embodiments, the chromaticity coordinate value x tends to decrease and the chromaticity coordinate value y tends to increase as the rate of replacement of Al with Sc increases. Thereby, the aluminate fluorescent substance concerning this form can be adjusted to a desired color tone.

  The rare earth aluminate phosphor of this embodiment preferably has a garnet structure, like the yttrium / aluminum / garnet phosphor. In addition to rare earth aluminate phosphors, rare earth aluminate phosphors, alkaline earth silicate phosphors, alkaline earth halogen apatite phosphors, alkaline earth borate halogen phosphors, alkaline earth aluminates It is preferable to have at least one phosphor selected from a salt, a rare earth oxysulfide phosphor, a nitride phosphor, an oxynitride phosphor or an organic complex phosphor.

  Thereby, it can be set as the light-emitting device which has various chromaticity and brightness | luminance for every predetermined area | region of a light-emitting device. For example, the phosphor of Comparative Example 3 can be arranged in a region different from the region where the phosphor of Example 3 is arranged, and the luminance can be changed for each predetermined observation region of the light emitting element. In addition, by changing the type of the phosphor combined with the light emitting element, it becomes easy to change the chromaticity or luminance for each light emitting device, and to make an illumination device for illumination that combines these light emitting devices. For example, it is set as the illuminating device for electrical decoration which has a light-emitting device provided with the fluorescent substance of the said Example 3, and a light-emitting device provided with the fluorescent substance of the said comparative example 2. FIG. This makes it easy to change the luminance of the light emitting device while maintaining the chromaticity substantially constant by changing the type of the phosphor without requiring a control means for changing the output of the light emitting element.

(Rare earth aluminate phosphor manufacturing method)
The rare earth aluminate phosphor of the present invention can be produced, for example, as follows, but is not limited thereto.

  First, a mixture as a raw material is prepared. Each constituent element is mixed so as to have a predetermined composition ratio to obtain a phosphor raw material mixture. The compound used for the raw material mixture of the phosphor is selected according to the elements constituting the target composition. The compound having the constituent elements (a) to (d) as described above can be, for example, an oxide or a compound that easily becomes an oxide at a high temperature.

  The mixing method is, for example, (1) a method in which a powdery compound is mixed as it is to obtain a raw material mixture, and (2) a mixture in a slurry form using water and / or an organic solvent and then dried to obtain a raw material mixture. (3) A method in which an aqueous solution of the above-mentioned compound is mixed and precipitated, and the resulting precipitate is dried to obtain a raw material mixture. (4) A method in which these are used in combination.

  Next, the raw material mixture is fired. The firing temperature, time, atmosphere, and the like are not particularly limited, and can be appropriately determined according to the purpose.

  The lower limit of the firing temperature is preferably 800 ° C. This is because if the firing temperature is lower than this temperature, unreacted raw materials remain in the fluorescent material, which may affect the light emission characteristics of the fluorescent material. On the other hand, the upper limit of the firing temperature is preferably 2000 ° C. This is because if the firing temperature is higher than this temperature, the particle size of the fluorescent material becomes too large and the light emission characteristics may deteriorate.

  The firing time is preferably 1 to 20 hours. When the firing time is short, the diffusion reaction between the raw material particles does not proceed. This is because if the firing time is long, firing after the diffusion reaction is almost completed is wasted, and coarse particles may be formed by sintering.

  The firing may be divided into a plurality of firing steps. For example, the first baking step can be performed at 800 to 1000 ° C. for 2 to 3 hours, and the second baking step can be performed at 1300 to 1600 ° C. for 2 to 3 hours.

The firing atmosphere is, for example, air, oxygen gas, a mixed gas of these with an inert gas such as nitrogen gas or argon gas, an atmosphere in which the oxygen concentration (oxygen partial pressure) is controlled, a weak oxidizing atmosphere, H ₂ , N _2. And reducing atmosphere. In particular, a reducing atmosphere such as H ₂ and N ₂ is preferable.

  After firing the raw material mixture, it is pulverized using a rough mortar, ball mill, vibration mill, pin mill, jet mill or the like, and passed through a sieve to obtain a powder having a desired particle size.

(Rare earth aluminate phosphor)
The light-emitting device in this embodiment can also include a rare earth aluminate-based phosphor as a fluorescent material. The rare earth aluminate-based phosphor is at least one element selected from the group consisting of Al, Y, Lu, Sc, La, Gd, Tb, Eu and Sm, and a kind selected from Ga and In. And an oxide phosphor having at least one element selected from Ce, Pr and other rare earth elements as an activator. For example, YAlO ₃ : Ce, Y ₃ Al ₅ O ₁₂ : Ce, Y ₄ Al ₂ O ₉ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al _{0.8 Ga 0.2) 5 O 12: Ce} , Tb 2.95 Ce 0.05 Al 5 O 12, Y 2.90 Ce 0.05 Tb 0.05 Al 5 O 12, Y 2.94 Ce 0.05 Pr _0.01 Al ₅ O ₁₂ , Y _2.90 Ce _0.05 Pr _0.05 Al ₅ O ₁₂ , (Lu _0.99 Ce _0.01 ) ₃ Al ₅ O ₁₂ , (Lu _0.90 Ce _0.10 ) ₃ Al ₅ O ₁₂ , (Lu _0.99 Ce _0.01 ) ₃ (Al _0.5 Ga _0.5 ) ₅ O ₁₂ .

In particular, at the time of high luminance and long-term use, the general formula _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1 However, Re is at least one element selected from the group consisting of Y, Gd, and La.) Yttrium, aluminum, garnet phosphor (hereinafter referred to as “YAG phosphor”) Is preferred). Since such a YAG phosphor has a garnet structure, it is resistant to heat, light and moisture, and the excitation spectrum peak can be set to around 470 nm. In addition, the emission peak is in the vicinity of 530 nm, and a broad emission spectrum that extends to 720 nm can be provided.

  YAG-based phosphors activated with cerium are resistant to heat, light, and moisture, and the peak wavelength of the excitation absorption spectrum can be adjusted to around 420 nm to 470 nm. Also, the emission peak wavelength λp is near 510 nm, and has a broad emission spectrum that extends to the vicinity of 700 nm. On the other hand, the YAG phosphor that emits red light, which is an yttrium-aluminum oxide phosphor activated by cerium, has a garnet structure, is resistant to heat, light and moisture, and has a peak wavelength of 420 nm in the excitation absorption spectrum. To about 470 nm. Further, the emission peak wavelength λp is in the vicinity of 600 nm, and has a broad emission spectrum that extends to the vicinity of 750 nm.

  The rare earth aluminate-based phosphor can be manufactured by the following method. First, phosphors use oxides or compounds that easily become oxides at high temperatures as raw materials for Y, Gd, Ce, La, Al, Sm, Pr, Tb and Ga, and they are added in a stoichiometric ratio. Mix thoroughly to obtain the raw material. Or a coprecipitated oxide obtained by calcining a solution obtained by coprecipitation of oxalic acid with a solution obtained by dissolving a rare earth element of Y, Gd, Ce, La, Sm, Pr, and Tb in an acid at a stoichiometric ratio with acid; Aluminum and gallium oxide are mixed to obtain a mixed raw material. An appropriate amount of fluoride such as ammonium fluoride is mixed with this as a flux and packed in a crucible, fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then the fired product in water. It can be obtained by ball milling, washing, separating, drying and finally passing through a sieve.

(Nitride phosphor)
The fluorescent material in the present embodiment contains N and is selected from at least one element selected from Be, Mg, Ca, Sr, Ba, and Zn, and C, Si, Ge, Sn, Ti, Zr, and Hf And a nitride-based phosphor activated with at least one element selected from rare earth elements. In addition, the nitride-based phosphor in this embodiment refers to a phosphor that emits light when excited by absorbing visible light, ultraviolet light, or light emitted from another phosphor. For _{example, Sr 2 Si 5 N 8:} Eu, Pr, Ba 2 Si 5 N 8: Eu, Pr, Mg 2 Si 5 N 8: Eu, Pr, Zn 2 Si 5 N 8: Eu, Pr, SrSi 7 N 10 _{: Eu, Pr, BaSi 7 N} 10: Eu, Ce, MgSi 7 N 10: Eu, Ce, ZnSi 7 N 10: Eu, Ce, Sr 2 Ge 5 N 8: Eu, Ce, Ba 2 Ge 5 N 8: _{Eu, Pr, Mg 2 Ge 5} N 8: Eu, Pr, Zn 2 Ge 5 N 8: Eu, Pr, SrGe 7 N 10: Eu, Ce, BaGe 7 N 10: Eu, Pr, MgGe 7 N 10: Eu _{, Pr, ZnGe 7 N 10:} Eu, Ce, Sr 1.8 Ca 0.2 Si 5 N 8: Eu, Pr, Ba 1.8 Ca 0.2 Si 5 N 8: Eu, Ce, Mg 1.8 Ca _0.2 Si ₅ N ₈ : Eu, Pr, Zn _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Ce, Sr _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, La, etc. Not to say that it is not done.

In particular, the basic constituent element of the nitride-based phosphor is represented by the general formula L _X Si _Y N _{(2 / 3X + 4 / 3Y)} : Eu (L is any one of Sr, Ca, Sr and Ca). In the general formula, X and Y are preferably X = 2, Y = 5, or X = 1, Y = 7. Specifically, the basic constituent elements, Mn is added _{(Sr X Ca 1-X)} 2 Si 5 N 8: Eu, Sr 2 Si 5 N 8: Eu, Ca 2 Si 5 N 8: Eu, Sr _{X Ca 1-X Si 7 N} 10: Eu, SrSi 7 N 10: Eu, CaSi 7 N 10: it is preferable to use a phosphor represented by Eu.

The nitride-based phosphor has europium (Eu), which is a rare earth element, at the emission center. The nitride phosphor uses Eu ²⁺ as an activator relative to the base alkaline earth metal silicon nitride. Mn, which is an additive, promotes diffusion of Eu ²⁺ and improves luminous efficiency such as luminous brightness, energy efficiency, and quantum efficiency. Mn is contained in the raw material, or Mn alone or a Mn compound is contained in the manufacturing process and fired together with the raw material.

Hereinafter, a nitride-based phosphor: While explaining the manufacturing method of _{((Sr X Ca 1-X} ) 2 Si 5 N 8 Eu), of course, not limited to this manufacturing method.

Raw materials Sr and Ca are pulverized. The raw materials Sr and Ca are preferably used alone, but compounds such as imide compounds and amide compounds can also be used. The raw materials Sr and Ca may contain B, Al, Cu, Mg, Mn, MnO, Mn ₂ O ₃ , Al ₂ O ₃ and the like. The raw materials Sr and Ca are pulverized in a glove box in an argon atmosphere.

The raw material Si is pulverized. The raw material Si is preferably a simple substance, but a nitride compound, an imide compound, an amide compound, or the like can also be used. For example, Si ₃ N ₄ , Si (NH ₂ ) ₂ , Mg ₂ Si, or the like. Similar to the raw materials Sr and Ca, Si is pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere.

  Next, the raw materials Sr and Ca are nitrided in a nitrogen atmosphere. Sr and Ca are nitrided in a nitrogen atmosphere at 600 to 900 ° C. for about 5 hours. Sr and Ca may be mixed and nitrided, or may be individually nitrided. Thereby, a nitride of Sr and Ca can be obtained. The raw material Si is nitrided at 800 to 1200 ° C. for about 5 hours in a nitrogen atmosphere. Thereby, silicon nitride is obtained.

Sr, Ca or Sr—Ca nitride is pulverized. Sr, Ca, and Sr—Ca nitrides are pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere. Similarly, Si nitride and Eu compound Eu ₂ O ₃ are pulverized.

After the pulverization, Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ are mixed, and Mn is added. Since these mixtures are easily oxidized, they are mixed in a glove box in an Ar atmosphere or a nitrogen atmosphere.

Finally, a mixture of Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ is fired in an ammonia atmosphere. A phosphor represented by (Sr _X Ca _1-X ) ₂ Si ₅ N ₈ : Eu to which Mn is added can be obtained by firing. However, the composition of the target phosphor can be changed by changing the blending ratio of each raw material.

  For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature can be in the range of 1200 to 1700 ° C, but the firing temperature is preferably 1400 to 1700 ° C. By using the above manufacturing method, it is possible to obtain a target phosphor.

(Oxynitride phosphor)
In addition to the fluorescent material described above, the fluorescent material in the present embodiment can further contain an oxynitride phosphor represented by the following general formula.
_{L x M y O z N {} (2 / 3x + (4/3) y- (2/3) z}: R
However, L has at least one element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn, and M is from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. Having at least one element selected. N is nitrogen, O is oxygen, and R is a rare earth element. x, y, and z satisfy the following numerical values.
x = 2, 4.5 ≦ y ≦ 6, 0.01 <z <1.5
Or x = 1, 6.5 ≦ y ≦ 7.5, 0.01 <z <1.5
Or x = 1, 1.5 ≦ y ≦ 2.5, 1.5 ≦ z ≦ 2.5
Hereinafter, although the manufacturing method of oxynitride fluorescent substance is demonstrated, it cannot be overemphasized that it is not limited to this manufacturing method. First, L nitride, M nitride and oxide, and rare earth element oxide are mixed as raw materials so as to obtain a predetermined blending ratio. By changing the blending ratio of each raw material, the composition of the target phosphor can be changed.

Next, the mixture of the above raw materials is put into a crucible and fired. For firing, a tubular furnace, a small furnace, a high-frequency furnace, a metal furnace, or the like can be used. The firing temperature is not particularly limited, but the firing is preferably performed in the range of 1200 to 1700 ° C, more preferably 1400 to 1700 ° C. The phosphor material is preferably fired using a boron nitride (BN) crucible and boat. Besides the crucible made of boron nitride, a crucible made of alumina (Al ₂ O ₃ ) can also be used. Moreover, it is preferable to perform baking in a reducing atmosphere. The reducing atmosphere is a nitrogen atmosphere, a nitrogen-hydrogen atmosphere, an ammonia atmosphere, an inert gas atmosphere such as argon, or the like. By using the above manufacturing method, the target oxynitride phosphor can be obtained.

(Alkaline earth metal silicate)
The fluorescent substance in the present embodiment can also contain an alkaline earth metal silicate activated with europium as the phosphor. The alkaline earth metal silicate can be a light-emitting device that emits warm color mixed light using blue light as excitation light. The alkaline earth metal silicate is preferably an alkaline earth metal orthosilicate represented by the following general formula.
(2-x-y) SrO · x (Ba, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation Medium, 0 <x <1.6, 0.005 <y <0.5, 0 <a, b, c, d <0.5.)
(2-x-y) BaO · x (Sr, Ca) O · (1-a-b-c-d) SiO 2 · aP 2 O 5 bAl 2 O 3 cB 2 O 3 dGeO 2: yEu 2+ ( Equation (Inside, 0.01 <x <1.6, 0.005 <y <0.5, 0 <a, b, c, d <0.5.)
Here, preferably, at least one of the values of a, b, c and d is greater than 0.01.

The fluorescent substance in the present embodiment is a phosphor composed of an alkaline earth metal salt, in addition to the alkaline earth metal silicate described above, alkaline earth metal aluminate activated by europium and / or manganese, and Y (V , P, Si) O ₄ : Eu, or an alkaline earth metal-magnesium-disilicate represented by the following formula:

Me (3-xy) MgSi ₂ O ₃ : xEu, yMn (wherein 0.005 <x <0.5, 0.005 <y <0.5, Me represents Ba and / or Sr and / or Or Ca.)
As the alkaline earth metal silicate in this embodiment, specifically, Sr _1.4 Ba _0.6 SiO ₄ : Eu ²⁺ , Sr _1.6 Ba _0.4 SiO ₄ : Eu ²⁺ , Sr _1.9 Ba _0.08 Ca _0.02 SiO ₄ : Eu ²⁺ , Sr _1.9 Ba _0.02 Ca _0.08 SiO ₄ : Eu ²⁺ , Sr _0.4 Ba _1.6 SiO ₄ : Eu ²⁺ , Sr _1.6 Ba _0.4 (Si _0.08 B _0.02 ) O ₄ : Eu ²⁺ , Sr _0.6 Ba _1.4 SiO ₄ : Eu ^{2 +} . Needless to say, the composition formulas are not limited to these.

  Next, the manufacturing process of the phosphor made of alkaline earth metal silicate in the present embodiment will be described. For the production of alkaline earth metal silicates, the stoichiometric amounts of the starting materials alkaline earth metal carbonate, silicon dioxide and europium oxide are intimately mixed according to the selected composition, and the phosphor is produced. In a conventional solid reaction, the desired phosphor is converted at a temperature of 1100 ° C. and 1400 ° C. under a reducing atmosphere. At this time, it is preferable to add less than 0.2 mol of ammonium chloride or other halide. If necessary, part of silicon can be replaced with germanium, boron, aluminum, and phosphorus, and part of europium can be replaced with manganese.

One of the phosphors as described above, ie, alkaline earth metal aluminates activated with europium and / or manganese, Y (V, P, Si) O ₄ : Eu, Y ₂ O ₂ S: Eu ³⁺ By combining one or these phosphors, an emission color having a desired color temperature and high color reproducibility can be obtained.

(Alkaline earth metal halogen borate phosphor)
The alkaline earth metal borate phosphor is, for example, a fluorescent material represented by the general formula ((M _{1 -xy} Eu _x M ′ _y ) ₂ B ₅ O ₉ M ″, where M is Mg. , Ca, Ba, Sr, M ′ is a red light emitting activator, and has at least one selected from Mn, Fe, Cr, Sn, and 0.0001 ≦ x ≦ 0.5, 0.0001 ≦ y ≦ 0.5. M ″ has at least one selected from halogen elements of F, Cl, Br, and I. x is the first activator Eu element. 0.0001 ≦ x ≦ 0.5, which indicates the composition ratio. When x is less than 0.0001, the emission luminance decreases, and even when x exceeds 0.5, the emission luminance tends to decrease due to concentration quenching. More preferably, 0.005 ≦ x ≦ 0.4, and still more preferably 0.01 ≦ x. In addition, y represents the composition ratio of at least one element of Mn, Fe, Cr, and Sn, preferably 0.0001 ≦ y ≦ 0.5, more preferably 0.8. 005 ≦ y ≦ 0.4, more preferably 0.01 ≦ y ≦ 0.3 When y exceeds 0.5, the emission luminance tends to decrease due to concentration quenching. Specific examples of the metal halide borate phosphors include (Ca, Ba, Sr) ₂ B ₅ O ₉ Cl: Eu (Mn).

A method for forming the alkaline earth metal halogen borate phosphor will be described below. Predetermined amounts of various chemical compounds that can be converted into oxides of oxides or oxides by thermal decomposition and ammonium chloride are weighed and mixed with a ball mill or the like, and put in a crucible in a reducing atmosphere of N ₂ and H ₂ . Baked at a temperature of 500 ° C. to 1000 ° C. for 3 to 7 hours. The obtained fired product can be pulverized wet, sieved, dehydrated and dried to obtain a powder of an alkaline earth metal borate phosphor.

  Alkaline earth metal halogen borate phosphors are blue to white (for example, white in conventional colors of JIS Z8110) by excitation light in the visible region of the relatively short wavelength from the ultraviolet region (for example, the dominant wavelength is 440 nm or less). Alternatively, the light emission colors of white) to red can be shown.

  In particular, since the main wavelength can be efficiently emitted with high luminance by ultraviolet light having a relatively long wavelength or short-wavelength visible light, and the red component is sufficiently contained, the average color rendering index Ra is 90 or more. It can also be obtained.

(Other phosphors)
In the present embodiment, a phosphor that emits light when excited by ultraviolet light can also be used as the phosphor, and specific examples include the following phosphors.
(1) Eu, Mn or alkaline earth halogen apatite phosphor activated with Eu and Mn; for example, M ₅ (PO ₄ ) ₃ (Cl, Br): Eu (where M is Sr, Ca, Ba, Phosphor such as Ca ₁₀ (PO ₄ ) ₆ ClBr: Mn, Eu, or the like selected from Mg.
(2) Eu, Mn or alkaline earth aluminate phosphor activated by Eu and Mn; for example, BaMg ₂ Al ₁₆ O ₂₇ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, Sr ₄ Al ₁₄ Phosphors such as O ₂₅ : Eu, SrAl ₂ O ₄ : Eu, CaAl ₂ O ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Mn and the like.
(3) A rare earth oxysulfide phosphor activated with Eu; for example, a phosphor such as La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, or Gd ₂ O ₂ S: Eu.
(4) (Zn, Cd) S: Cu, Zn ₂ GeO ₄ : Mn, 3.5 MgO · 0.5 MgF ₂ · GeO ₂ : Mn, Mg ₆ As ₂ O ₁₁ : Mn, (Mg, Ca, Sr, Ba ) Ga ₂ S ₄ : Eu, Ca ₁₀ (PO ₄ ) ₆ FCl: Sb, Mn, (5) Organic complex phosphor activated with Eu.

  In addition, these phosphors may be used alone in a single-layer wavelength conversion member, or may be used as a mixture. Furthermore, they may be used alone or in combination in a wavelength conversion member in which two or more layers are laminated.

[Light emitting element]
The light-emitting element in this embodiment is preferably a semiconductor light-emitting element having a light-emitting layer capable of emitting a light emission wavelength capable of efficiently exciting a fluorescent substance. Examples of the material of such a semiconductor light emitting device include various semiconductors such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN. Especially as a material of a light emitting layer capable of efficiently emitting a short wavelength of visible light from an ultraviolet region capable of efficiently exciting a fluorescent substance, a nitride semiconductor (for example, a nitride semiconductor containing Al or Ga, a nitride containing In or Ga) the semiconductor as _{in X Al Y Ga 1-X} -Y N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) can be mentioned as more preferable.

  As a semiconductor structure, a homostructure having a MIS junction, a pn junction, or the like, a heterostructure, or a double hetero configuration is preferably exemplified. Various emission wavelengths can be selected depending on the semiconductor layer material and the mixed crystal ratio. Further, the output can be further improved by adopting a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film that produces a quantum effect.

  When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, GaAs, or GaN is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by HVPE method, MOCVD method or the like. A buffer layer made of GaN, AlN, GaAIN or the like is grown at a low temperature on the sapphire substrate to form a non-single crystal, and a nitride semiconductor having a pn junction is formed thereon.

As an example of a light emitting element capable of efficiently emitting light in an ultraviolet region having a pn junction using a nitride semiconductor, SiO ₂ is formed in a stripe shape on the buffer layer substantially perpendicular to the orientation flat surface of the sapphire substrate. GaN is grown on the stripe using the HVPE method. Subsequently, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum nitride / gallium, a well layer of indium nitride / aluminum / gallium, and aluminum nitride / gallium are formed by MOCVD. An active layer having a multiple quantum well structure in which a plurality of barrier layers are stacked, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. Examples include a double hetero configuration. A semiconductor laser device may be provided by providing a guide layer and a cavity end face in the active layer.

  Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, it is preferable to dope p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. When the sapphire substrate is not used, the contact layer is exposed by etching from the p-type side to the surface of the first contact layer. A light emitting element made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips after forming electrodes on each contact layer.

  In the light-emitting device of this embodiment, it is preferable to use a light-transmitting resin such as an epoxy resin or a silicone resin as the material for binding the fluorescent substance in order to improve mass productivity. Here, in consideration of excitation efficiency of the fluorescent substance, deterioration of the light-transmitting resin, and the like, the light-emitting element has an emission spectrum in a blue region, and the main emission wavelength is preferably 400 nm to 500 nm, preferably 420 nm to 490 nm. More preferred.

  Hereinafter, the light emitting device having the rare earth aluminate phosphor according to the present invention will be described with reference to examples. However, the present invention is not limited to these examples.

  FIG. 1 is a schematic top view of a light emitting device 100 according to this embodiment. FIG. 2 is a cross-sectional view taken along the line II of FIG. The light emitting device 100 according to this embodiment includes a support member 110 having a recess in which a light emitting element is placed, a covering member 108 that covers the light emitting element 103 and the conductive wire 102 connected to the light emitting element 103, and the covering member 108. And a fluorescent material 109 contained in the. Further, as shown in FIG. 1, the light emitting device 100 has notches at four corners of the support member 110, and the conductor wiring 101 is exposed at the notches, and is electrically connected to external electrodes. Can do. Note that the conductor wiring 101 exposed at the notch is electrically connected to the conductor wiring 104 disposed in the recess of the support member 110.

  The light emitting element in this example is an LED chip having an InGaN semiconductor with an emission peak wavelength of about 460 nm as a light emitting layer. The specific element structure of this LED chip is that an n-type GaN layer that is an undoped nitride semiconductor on a sapphire substrate, a GaN layer that forms an n-type contact layer by forming an Si-doped n-type electrode, and an undoped nitride The single quantum well structure includes an n-type GaN layer that is a semiconductor, an n-type AlGaN layer that is a nitride semiconductor, and then an InGaN layer that constitutes a light-emitting layer. On the light emitting layer, an AlGaN layer as a p-type cladding layer doped with Mg and a GaN layer as a p-type contact layer doped with Mg are sequentially laminated. A GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.

  Etching is performed on the nitride semiconductor on the sapphire substrate to expose the surface of each pn contact layer. Positive and negative pedestal electrodes are formed on each contact layer by sputtering. After a scribe line is drawn on the semiconductor wafer thus completed, it is divided by an external force to form an LED chip as a light emitting element.

  An LED chip is die-bonded to the center of the bottom surface of the recess of the support member 110 using an epoxy resin as an adhesive. After this adhesive is cured at 140 ° C. for 2 hours, the electrode of the LED chip and the conductor wiring 104 of the support member 110 are each wire-bonded with a gold wire having a diameter of 30 μm.

Next, a method for forming a phosphor in this example will be described. First, _Sc 2 _{O 3} as a raw material 20.7 g, a CeO ₂ 2.58 g, _Gd 2 a _{O 3} 51.7 g, _Al 2 a _{O 3} were weighed 10.2g, respectively, a mixer such as a ball mill both appropriate amount of flux Mix thoroughly dry. Next, the mixed raw materials are packed in a crucible such as alumina, and the temperature is raised to 1100 to 1400 ° C. at 300 ° C./hr in a reducing atmosphere of N ₂ and H ₂ , and the temperature is kept at 1200 to 1400 ° C. for about 3 hours. Bake. The obtained pulverized calcined product, the dispersion to obtain a powder of the phosphor represented by a composition formula of _{Gd 2.85 Ce 0.15 Sc 3 Al 2} O 12 sieved. The emission color of the obtained phosphor by excitation at 460 nm is light in the yellow region.

  In the light emitting device 100 according to the present embodiment, the covering member 108 formed in the concave portion of the support member 110 is a wavelength conversion member containing the fluorescent material 109. A method for forming the covering member 108 in this embodiment will be described. First, 10 wt% of the alkaline earth oxide phosphor is contained in the silicone resin composition, and the mixture is stirred for 5 minutes with a rotation and revolution mixer. The curable composition thus obtained is filled into the recesses of the package. Finally, heat treatment is performed at 70 ° C. × 2 hours and 150 ° C. × 1 hour.

  According to this embodiment, a light-emitting device that emits mixed light of light emitted from a light-emitting element in a blue region and fluorescence in a yellow region by a fluorescent material that has absorbed the light emission can be provided.

  In this example, the lighting device is a combination of the first light-emitting device formed in Example 1 and the second light-emitting device described below.

First, the phosphor in the second light-emitting device of this example is formed as follows. First, a solution obtained by dissolving rare earth elements of Y, Gd, and Ce in acid at a stoichiometric ratio is coprecipitated with oxalic acid. A co-precipitated oxide obtained by firing this and aluminum oxide are mixed to obtain a mixed raw material. This was mixed with ammonium fluoride as a flux, packed in a crucible, and fired in air at a temperature of 1400 ° C. for 3 hours to obtain a fired product. The fired product was ball milled in water, washed, separated, dried, and finally formed through a sieve. In this way, the phosphor represented by Gd _0.6 Ce _0.03 Y _2.4 Al ₅ O ₁₂ shown as Comparative Example 2 in Table 2 above is formed. Similar to Example 1, the phosphor is contained in a covering member formed in the concave portion of the support member, thereby obtaining a second light emitting device.

  Further, the first light-emitting device and the second light-emitting device are combined to form a lighting device having different brightness for each of the first light-emitting device and the second light-emitting device. That is, by supplying the same amount of power to the first light emitting device and the second light emitting device, mixed light of light from the light emitting element and fluorescence of the fluorescent material is output from each light emitting device. As a result, the color tone is made substantially constant for each predetermined observation region without requiring a driving means for controlling the amount of power for each light-emitting device, by simply changing the type of phosphor having a garnet structure with excellent emission characteristics. A simple lighting device in which the luminance is changed stepwise can be obtained.

  The light emitting device according to the present invention can be used for various light sources such as lighting, signals, illumination, displays, indicators, and backlights of mobile phones.

FIG. 1 is a schematic top view of a light emitting device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention. FIG. 3 is a diagram showing the light emission characteristics of the phosphor in one example of the present invention. FIG. 4 is a diagram showing the light emission characteristics of the phosphor in one example of the present invention. FIG. 5 is a diagram showing the light emission characteristics of the phosphor in one example of the present invention. FIG. 6 is a diagram showing the light emission characteristics of the phosphor in one example of the present invention. FIG. 7 is a diagram showing the light emission characteristics of a phosphor as a comparative example of the present invention. FIG. 8 is a diagram showing the light emission characteristics of a phosphor as a comparative example of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Semiconductor device 101, 104 ... Conductor wiring 102 ... Conductive wire 103 ... Semiconductor element 108 ... Cover member 109 ... Fluorescent substance 110 ... Support member

Claims (3)

In a light emitting device comprising: a semiconductor light emitting element; and a fluorescent material that emits light having a different wavelength by absorbing at least part of the light from the semiconductor light emitting element.
The phosphor material includes a phosphor having a general formula represented by the following formula:
_{(Gd 1-y, Ce y} ) 3 (Al 1-m, Sc m) 5 O 12
However, y and m are 0.0001 ≦ y ≦ 0.3 and 0.1 ≦ m ≦ 0.9.   The fluorescent material includes rare earth aluminate-based phosphor, alkaline earth silicate phosphor, alkaline earth halogen apatite phosphor, alkaline earth borate halogen phosphor, alkaline earth aluminate, rare earth oxysulfide The light emitting device according to claim 1, comprising at least one phosphor selected from a phosphor, a nitride phosphor, an oxynitride phosphor, or an organic complex phosphor. The first light-emitting device according to claim 1, and a second light-emitting device including a yttrium, aluminum, and garnet phosphor instead of the phosphor according to claim 1. ,
The lighting device, wherein the amounts of electric power supplied to the first light emitting device and the second light emitting device are substantially the same.

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