JP2005093912A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device of an amber color which has a relatively broad emission spectrum, and less color shift. <P>SOLUTION: The light-emitting device comprises a light-emitting element which emits a light extending from ultraviolet to blue, a first phosphor which is excited by the light emitted from the light-emitting element to emit first light whose wavelength is longer than that of the excitation light, and a second phosphor, comprising a nitride phosphor, which is excited by the light emitted from the light-emitting element to emit second light whose wavelength is further longer than the first light. Its emission color is a mixture of the first light and the second light. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light emitting device including a light emitting element and a phosphor, and more particularly to an amber light emitting device.

  Conventionally, the amber color for traffic signals has been an incandescent bulb with a colored glass filter or an AlInGaP light emitting diode (LED). Since the type with a colored glass filter has a problem that it is difficult to recognize the presence or absence of lighting by simulating light emission by sunlight, recently, an AlInGaP-based light emitting diode (LED) has been widely used. It was.

JP-A-8-306957

However, although the AlInGaP-based light emitting diode (LED) has the advantages that it is efficient, can be manufactured relatively inexpensively, and has no pseudo light emission due to sunlight, the emission spectrum of the AlInGaP-based light emitting diode is a line spectrum ( Because of its narrow and sharp spectrum, there is a problem that it is difficult for people with color blindness to recognize.
In addition, there is a problem that color shift occurs when the input current to the light emitting element changes.

  Accordingly, an object of the present invention is to provide an amber light emitting device having a relatively broad broad emission spectrum and little color shift.

In order to achieve the above object, a first light emitting device according to the present invention includes a light emitting element that emits ultraviolet to blue light, and a light having a longer wavelength range than the excitation light that is excited by light emitted from the light emitting element. A first phosphor that emits first light and a nitride phosphor that emits second light in a longer wavelength region than the first light when excited by the light emitted from the light-emitting element. And having a light emission color due to a color mixture of the first light and the second light.
Here, the nitride phosphor is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, C, Si, Ge, Sn, Ti, Zr, At least one group IV element selected from the group consisting of Hf and N, and consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu A phosphor activated by at least one rare earth element selected from the group.

The light emitting device according to the present invention including the nitride phosphor configured as described above is a light emitting device capable of amber light emission because the emission color of the nitride phosphor is in a yellow to yellow-red region. realizable.
In addition, the amber light emitting device according to the present invention has a wide half-value width of 50 nm or more because the emission spectrum of the nitride phosphor can be easily recognized by a person with color blindness.

The nitride phosphor has the general formula L _X M _Y N _{((2/3) X + (4/3) Y)} : R or L _X M _Y O _Z N _{((2/3) X + (4 / 3) Y- (2/3) Z)} : R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. At least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, At least one rare earth element selected from the group consisting of Tb, Dy, Ho, Er, and Lu, where X, Y, and Z are 0.5 ≦ X ≦ 3, 1.5 ≦ Y ≦ 8, and 0 <. It is preferable that the nitride phosphor represented by Z ≦ 3.

In the light emitting device according to the present invention, when the light emitting element is configured using a blue light emitting element, the first phosphor is preferably a YAG phosphor.
Here, the YAG phosphor has a garnet structure containing Y and Al, and refers to a phosphor activated with at least one element selected from rare earth elements. This YAG phosphor is referred to as the nitride fluorescence. By using it together with the body, a light emitting device capable of easily emitting amber light can be realized.

In the light emitting device according to the present invention, when an ultraviolet light emitting element is used as the light emitting element, the first phosphor is preferably an oxynitride phosphor.
Here, the oxynitride phosphor uses a rare earth element as an activator, and is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and A phosphor including an oxynitride phosphor crystal containing at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf.

In the present invention, the oxynitride phosphor has the general formula L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _X M _{Y Q T O Z N ((} 2/3) X + (4/3) Y + T- (2/3) Z): R ( where, L is composed of Be, Mg, Ca, Sr, Ba, and Zn group It is a Group II element that is at least one selected from: M is a Group IV element that is at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. Q is at least one group III element selected from the group consisting of B, Al, Ga, and In, O is an oxygen element, N is a nitrogen element, and R is a rare earth element The element is 0.5 <X <1.5, 1.5 <Y <2.5, 0 <T <0.5, 1.5 <Z <2.5. It is preferably in a oxynitride phosphor represented.

  Furthermore, in the light emitting device according to the present invention, the nitride phosphor is preferably a nitride phosphor containing Ca and Si.

  Still further, in the light emitting device according to the present invention, the emission peak wavelength of the light emitting element is determined such that the peak wavelength of the first excitation spectrum of the first phosphor and the peak of the second excitation spectrum of the second phosphor. It is preferable to set the slopes of the first excitation spectrum and the excitation spectrum to be negative in the fluctuation range of the emission peak wavelength of the light emitting element, which is set longer than the wavelength.

In this way, the fluctuation of the ratio of the emission intensity of the first phosphor and the emission intensity of the second phosphor can be reduced, and the emission color fluctuation can be reduced.
In this case, it is preferable that the rate of change of the excitation efficiency of the first phosphor and the second phosphor with respect to the excitation wavelength is set to be substantially equal in the fluctuation range of the emission peak wavelength of the light emitting element. As a result, it is possible to eliminate fluctuations in the emission color.

In the light emitting device according to the present invention, it is preferable that the nitride phosphor contains B at a ratio of 1 ppm to 10000 ppm, thereby improving light emission characteristics such as light emission luminance and quantum efficiency. Thus, an amber light emitting device with high luminance is realized.
That is, by adding boron element to the nitride phosphor, the activator is diffused and the growth of particles is promoted, and the boron element enters the crystal lattice of the nitride phosphor and the crystal lattice. The distortion is removed. Thereby, the light emission luminance and quantum efficiency of the nitride phosphor are improved.
Here, the crystal structure of the nitride phosphor is monoclinic or orthorhombic.

Furthermore, in the light emitting device according to the present invention, it is preferable that the intensity of light directly leaking out of the light emitted from the light emitting element is 10% or less of the intensity at the main peak of light emission of the phosphor.
In this case, for example, even when a light emitting element that emits blue light is used, the emission color can be substantially determined by light emission of only the phosphor.

  A second light emitting device according to the present invention includes a light emitting element that emits ultraviolet light, a blue phosphor that emits blue light when excited by light emitted from the light emitting element, and a blue phosphor that is excited by the blue light and emits blue light. A first phosphor that emits first light in a longer wavelength region than light, and a nitride phosphor that emits second light in a longer wavelength region than the first light when excited by the blue light. And having a light emission color due to a color mixture of the first light and the second light.

In the second light emitting device according to the present invention configured as described above, the light emitting element excites the blue phosphor to generate blue light, and the blue light emits the first phosphor and the second fluorescence. The body is excited, and the emission color is determined by the color mixture of the first light and the second light.
The blue light emitted from the blue phosphor excited by the light of the light emitting element hardly changes the wavelength of the blue light even if the wavelength of the ultraviolet light of the light emitting element changes. Therefore, the first phosphor and the first phosphor The wavelength of light (blue light) that excites the second phosphor hardly changes.
Therefore, in the second light emitting device according to the present invention, even if the excitation wavelength dependency of the excitation efficiency of the first phosphor and the second phosphor is different, the emission intensity of the first phosphor The ratio of the emission intensity of the second phosphor does not change.
That is, the emission color of the second light emitting device according to the present invention is determined by the color mixture of the first light emitted from the first phosphor and the second light emitted from the second phosphor. However, even when the emission wavelength of the light emitting element fluctuates, the intensity ratio between the first light and the second light is kept constant, so that the emission color due to the color mixture does not change.

In the present invention, the nitride phosphor may have a general formula, L _X M _Y N _{((2/3) X + (4/3) Y)} : R or L _X M _Y O _Z N _{((2/3 ) X + (4/3) Y- (2/3) Z)} : R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf, R is Y, La, Ce, Pr, Nd, Sm, At least one rare earth element selected from the group consisting of Eu, Gd, Tb, Dy, Ho, Er, and Lu, where X, Y, and Z are 0.5 ≦ X ≦ 3 and 1.5 ≦ Y ≦. 8 and 0 <Z ≦ 3)).

  Further, the first phosphor is preferably a YAG phosphor.

  Further, the nitride phosphor is more preferably a nitride phosphor containing Ca and Si, and the nitride phosphor preferably contains B at a ratio of 1 ppm to 10000 ppm.

As described above, according to the present invention, an amber light emitting device can be provided.
It is also possible to realize amber color by using a color filter. However, in the structure using the color filter, there is a problem that the color of the color filter is observed when not lit, as in the present invention. When the amber color is realized only with the phosphor without using the color filter, the amber color is not observed when the light is not turned on, and for example, the present invention has excellent applicability for use as a traffic light.

  Hereinafter, the phosphor and the method for producing the same according to the present invention will be described using embodiments and examples. However, the present invention is not limited to this embodiment and example.

Embodiment 1 FIG.
The light emitting device according to the first embodiment of the present invention absorbs at least a part of blue light of a light emitting element (blue light emitting diode) that emits blue light having a relatively short wavelength of visible light. And a phosphor that emits amber light.
Here, in particular, the light emitting device according to the first embodiment is characterized by using a nitride phosphor and a YAG phosphor, which will be described later, and a desired amber color can be obtained by mixing colors of the two phosphors. Realized.

Specifically, in the first embodiment, first, the amber color, which is difficult to realize with only the YAG phosphor, is used by using a nitride phosphor with a large red component together with the YAG phosphor. Amber color is realized.
In the first embodiment, second, a light emitting element that emits visible blue light is used. The light emitting element is used to excite a nitride phosphor and a YAG phosphor. Blue light is not directly output to the outside, and amber light in which the light emission of the nitride phosphor and the light emission of the YAG phosphor are mixed is output.

Here, the amber color is a region composed of a long wavelength region of yellow in JIS standard Z8110 and a short wavelength region of yellow red, or a yellow region and a short wavelength region of yellow red in JIS standard Z9101 of safe colors. The chromaticity range of the sandwiched region corresponds to, for example, a region located in a range of 580 nm to 600 nm in terms of dominant wavelength.
Specifically, there are a vehicle-mounted amber color JIS standard and a yellow traffic signal light standard, but in this specification, the range including all of these standards is amber color.
More specifically, there is a SAE standard (SAE J588) as an amber color standard for in-vehicle use. According to this, the region (A) in the chromaticity charts of FIGS. x, y) = (0.56, 0.44), (0.54, 0.42), (0.60, 0.39), (0.61, 0.39) It is color. Similarly, there is a JIS standard (JIS D5500) as an amber color standard for in-vehicle use. According to this, the (B) region in the chromaticity charts of FIGS. ) = (0.571, 0.429), (0.564, 0.429), (0.595, 0.398), (0.602, 0.398) is an amber color. . Furthermore, there is a CIE standard (CIE DS004 2 / E-1996) as a yellow traffic signal light, which indicates the region (C) in the chromaticity charts of FIGS. 14 and 15, where (x, y) = (0 .547, 0.452), (0.536, 0.444), (0.593, 0.387), and (0.613, 0.387) are the amber colors. In the present specification, it is assumed that at least one in the range of (A) to (C) is amber.
The relationship between the color name and the chromaticity coordinate in the specification is based on the JIS standard (JIS Z8110).

Hereinafter, the configuration of the light-emitting device of Embodiment 1 will be described in detail.
As shown in FIG. 1, the light-emitting device of Embodiment 1 is separated from the light-emitting element 10 in the ultraviolet region, the cathode-side lead frame 13a having a cup for mounting the light-emitting element 10, and the lead frame 13a. The anode-side lead frame 13b provided, the coating member 12 including the phosphor 11 provided in the cup of the lead frame 13a, and a transparent mold member 15 covering the whole are provided. Nitride phosphors and YAG phosphors are used.
The positive electrode 3 of the light emitting element 10 is connected to the lead frame 13b by the conductive wire 14, and the negative electrode 4 of the light emitting element 10 is connected to the lead frame 13a by the conductive wire 14. 10, the conductive wire 14, the cup of the lead frame 13 a and the tip of the lead frame 13 b are covered with a transparent mold member 15.

The light emitting device according to the first embodiment configured as described above is manufactured as follows.
First, the light emitting element 10 is die-bonded (adhered) to the cup of the lead frame 13a with a die bonder.
After die bonding, the lead frame 13 is transferred to a wire bonder, the negative electrode 3 of the light emitting element is wire bonded to the upper end portion of the cup of the lead frame 13a with a gold wire (conductive wire), and the positive electrode 3 is connected to the other lead frame. Wire bond to 13b.

  Next, the phosphor 11 and the coating member 12 are injected into the cup of the lead frame 13a using a dispenser of the molding apparatus. The phosphor 11 and the coating member 12 are uniformly mixed in a desired ratio in advance before injection. In particular, in the light emitting device of the first embodiment, the emission color of the light emitting device is determined by the emission colors of the two phosphors, and the emission color changes when the blue light leaks directly outside. The phosphor content is set so as not to be output to the outside.

  And after inject | pouring the fluorescent substance 11 and the coating member 12, resin is hardened, after immersing the lead frame 13 in the mold frame in which the mold member 15 was injected previously, the resin is hardened again, and finally the mold frame By removing the, a bullet-type light emitting device as shown in FIG. 1 can be manufactured.

  Hereinafter, each element of the first embodiment will be described in more detail.

[Phosphor]
The phosphor used in the first embodiment is a combination of an yttrium / aluminum / garnet phosphor and a phosphor capable of emitting red light, particularly a nitride phosphor. These YAG phosphor and nitride phosphor are mixed as phosphor 11 and contained in coating member 12. A two-layer structure of a coating layer containing a YAG phosphor and a coating layer containing a nitride phosphor may be used.

Each phosphor will be described in detail.
(Yttrium / Aluminum / Garnet phosphor)
The yttrium / aluminum / garnet phosphor (YAG phosphor) used in the first embodiment is a general term for a garnet structure containing Y and Al, and is activated by at least one element selected from rare earth elements. The phosphor is excited by blue light emitted from the light emitting element 10 and emits light. The YAG-based phosphor, for _{example, (Re 1-x Sm x} ) 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1, where, Re is, Y And at least one element selected from the group consisting of Gd, La).
_{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce phosphor, for garnet structure, heat, resistant to light and moisture, in particular, when used for a long time at a high intensity Is preferred. Further, the peak of the excitation spectrum can be set around 470 nm. The emission peak is in the vicinity of 530 nm, and a broad emission spectrum that extends to 720 nm is obtained.

In particular, YAG-based phosphor, Al, Ga, In, Y , La and Gd and the Sm content is two or more kinds of _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12 : RGB wavelength components can be increased by mixing Ce phosphors. At present, there are some variations in the emission wavelength of the semiconductor light emitting device, but by mixing two or more kinds of phosphors, a desired white mixed color light or the like can be obtained. That is, by combining phosphors having different chromaticity points according to the emission wavelength of the light emitting element, light at an arbitrary point on the chromaticity diagram connected between the phosphors and the light emitting element can be emitted. .
The aluminum garnet-based phosphor includes Al and at least one element selected from Y, Lu, Sc, La, Gd, Tb, Eu, and Sm, and one element selected from Ga and In. And a phosphor activated by at least one element selected from rare earth elements and excited by visible light or ultraviolet light to emit light.

  In this type of phosphor having a garnet structure, the emission spectrum is shifted to the short wavelength side by substituting part of Al with Ga, and part of Y of the composition is replaced with Gd and / or La. Thus, the emission spectrum shifts to the longer wavelength side. In this way, it is possible to continuously adjust the emission color by changing the composition. Therefore, an ideal condition for converting white light emission using the blue light emission of the nitride semiconductor is provided such that the intensity on the long wavelength side is continuously changed by the composition ratio of Gd. If the Y substitution is less than 20%, the green component is large and the red component is small, and if it is 80% or more, the red component is increased, but the luminance is drastically decreased.

  Similarly, this type of phosphor having a garnet structure also has an excitation absorption spectrum that shifts the excitation absorption spectrum to the short wavelength side by substituting a part of Al with Ga. By substituting the part with Gd and / or La, the excitation absorption spectrum is shifted to the longer wavelength side. The peak wavelength of the excitation absorption spectrum of the phosphor is preferably shorter than the peak wavelength of the emission spectrum of the light emitting element. With this configuration, when the current input to the light emitting element is increased, the peak wavelength of the excitation absorption spectrum substantially matches the peak wavelength of the emission spectrum of the light emitting element, so that the excitation efficiency of the phosphor is not reduced. Occurrence of chromaticity deviation can be suppressed.

Specifically, in addition to the YAG phosphor described above, 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 , and the like, and those shown in Table 3 below may be mentioned. Of these, an yttrium-aluminum oxide phosphor containing Y and activated with Ce or Pr is preferable. In particular, it is preferable to use a combination of two or more phosphors having different compositions.
For example, an yttrium / aluminum oxide phosphor activated with cerium can emit green or red light. The phosphor capable of emitting green light has a garnet structure and is resistant to heat, light, and moisture. The peak wavelength of the excitation absorption spectrum is from 420 nm to 470 nm, and the emission peak wavelength λp is from 510 nm to 700 nm. It has a broad emission spectrum that draws a tail. The phosphor capable of emitting red light has a garnet structure, is resistant to heat, light and moisture, has a peak wavelength of excitation absorption spectrum of 420 nm to 470 nm, and an emission peak wavelength λp of 600 nm, which is 750 nm. It has a broad emission spectrum that extends to the vicinity.

When YAG phosphors are used, even if they are placed in contact with or close to LED chips with irradiance of (Ee) = 0.1 W · cm ⁻² or more and 1000 W · cm ⁻² or less, sufficient light resistance with high efficiency The light emitting device can be made to have the property.
The cerium-activated yttrium / aluminum oxide phosphor used in the first embodiment, which emits green light, has a garnet structure and is highly resistant to heat, light, and moisture. The peak wavelength of the absorption spectrum can be set in the range of 420 nm to 470 nm. Also, the emission peak wavelength λp is near 510 nm, and has a broad emission spectrum that extends to around 700 nm. On the other hand, the YAG phosphor capable of emitting 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 an excitation absorption spectrum of 420 nm. To 470 nm. In addition, 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.

  In YAG phosphors with a garnet structure, the emission spectrum can be shifted to the short wavelength side by substituting part of Al with Ga, and part of Y in the composition is replaced with Gd and / or La. By doing so, the emission spectrum can be shifted to the longer wavelength side. If the substitution of Y is less than 20%, the green component is large and the red component is small. On the other hand, at 80% or more, although the reddish component increases, the luminance rapidly decreases. Similarly, in the YAG phosphor having a garnet structure, the excitation absorption spectrum can be shifted to the short wavelength side by substituting part of Al with Ga. By substituting a part of Gd and / or La, the excitation absorption spectrum can be shifted to the longer wavelength side.

(Method for producing YAG phosphor)
The YAG phosphor of the first embodiment can be produced as follows.
First, oxides or compounds that easily become oxides at high temperatures are used as raw materials for Y, Gd, Ce, La, Al, Lu, Tb, Sc, Pr, Sm, and Ga. Mix thoroughly to obtain the raw material. Alternatively, coprecipitation oxidation 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, Lu, Tb, Sc, Pr, Sm in an acid in a stoichiometric ratio with an acid. A mixed raw material is obtained by mixing the product with aluminum oxide and gallium oxide.
An appropriate amount of fluoride such as ammonium fluoride or NH ₄ Cl is mixed as a flux into this crucible and packed in a crucible and baked in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a baked product. The fired product can be produced by ball milling in water, washing, separating, drying, and finally passing through a sieve.

  The mixture of the raw material of the phosphor mixed with the raw material and the flux is fired in the atmosphere or weakly reducing atmosphere (first firing step) and then fired in the reducing atmosphere (second firing step). Step calcination is preferred. Here, the weak reducing atmosphere refers to a weak reducing atmosphere set to include at least the amount of oxygen necessary in the reaction process of forming a desired phosphor from the mixed raw material. By performing the first firing step until the formation of the phosphor structure is completed, blackening of the phosphor can be prevented and a decrease in light absorption efficiency can be prevented. In addition, the reducing atmosphere in the second firing step refers to a reducing atmosphere stronger than the weak reducing atmosphere. When firing in two stages in this way, a phosphor with high absorption efficiency at the excitation wavelength is obtained, and a light-emitting device with high efficiency is obtained.

  Moreover, in this Embodiment 1, you may comprise using the yttrium aluminum oxide type | system | group fluorescent substance activated with two or more types of cerium from which a composition differs. In this case, the two or more types of phosphors may be used in combination, or may be arranged as separate layers.

(Nitride phosphor)
The nitride phosphor in the light emitting device of the first embodiment is at least one selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. From at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn and C, Si, Ge, Sn, Ti, Zr, Hf A phosphor containing at least one group IV element selected from the group consisting of N and N.
O may be contained in the composition of the nitride phosphor.

Of the combinations of the above elements, a nitride phosphor composed of at least one element of Ca and Sr, Si, and N activated by Eu is particularly preferable.
That is, since the nitride phosphor using Ca is excellent in temperature characteristics, the deterioration rate can be kept small even when used for a long time. A nitride phosphor using Sr is the most preferable in terms of preventing light from the light emitting element from leaking to the outside because the particle size is the smallest among the nitride phosphors using Ca. Since the particle size is small, it is possible to prevent light from the light emitting element from leaking to the outside even when the concentration of the phosphor is small. Therefore, it is possible to suppress a decrease in light output due to an increase in the concentration of the phosphor.

  Based on this composition, a part of Eu is at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Lu. Can be replaced. A part of at least one of Ca and Sr can be substituted with at least one Group II element selected from the group consisting of Be, Mg, Ba, and Zn. A part of Si can be replaced by at least one group IV element selected from the group consisting of C, Ge, Sn, Ti, Zr, and Hf.

Specifically, the nitride phosphor of the first embodiment has a general formula L _X M _Y N _{((2/3) X + (4/3) Y)} : R or L _X M _Y O _Z N _{( (2/3) X + (4/3) Y- (2/3) Z)} : R (L is at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn) M is at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, and R is Y, La, Ce, Pr, At least one rare earth element selected from the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu, where X, Y, and Z are 0.5 ≦ X ≦ 3, 1. 5 ≦ Y ≦ 8 and 0 <Z ≦ 3)).

Preferred specific examples of the nitride phosphor included in the above general formula include (Sr _T Ca _1-T ) ₂ Si ₅ N ₈ : Eu, Ca ₂ Si ₅ N ₈ : Eu, Sr _T Ca _1-T Si ₇ N ₁₀ : Eu, SrSi ₇ N ₁₀ : Eu, CaSi ₇ N ₁₀ : Eu, Sr ₂ Si ₅ N ₈ : Eu, Ba ₂ Si ₅ N ₈ : Eu, Mg ₂ Si ₅ N ₈ : Eu, Zn ₂ Si ₅ N _{8: Eu, SrSi 7 N 10} : Eu, BaSi 7 N 10: Eu, MgSi 7 N 10: Eu, ZnSi 7 N 10: Eu, Sr 2 Ge 5 N 8: Eu, Ba 2 Ge 5 N 8: Eu, Mg ₂ Ge ₅ N ₈ : Eu, Zn ₂ Ge ₅ N ₈ : Eu, SrGe ₇ N ₁₀ : Eu, BaGe ₇ N ₁₀ : Eu, MgGe ₇ N ₁₀ : Eu, ZnGe ₇ N ₁₀ : Eu, Sr _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Ba _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Mg _1.8 Ca _0.2 Si ₅ N ₈ : Eu, Zn _1.8 Ca _{0 .2} Si ₅ N ₈ : Eu, Sr _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, Ba _0.8 Ca _0.2 Si ₇ N ₁₀ : Eu, Mg _0.8 Ca _0.2 Si ₇ N _{10: Eu, Zn 0.8 Ca 0.2} Si 7 N 10: Eu, Sr 0.8 Ca 0.2 Ge 7 N 10: Eu, Ba 0.8 Ca 0.2 Ge 7 N 10: Eu, Mg _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Zn _0.8 Ca _0.2 Ge ₇ N ₁₀ : Eu, Sr _0.8 Ca _0.2 Si ₆ GeN ₁₀ : Eu, Ba _0.8 Ca _{0 .2} Si ₆ GeN ₁₀ : Eu, Mg _0.8 Ca _0.2 Si ₆ GeN _{10: Eu, Zn 0.8 Ca 0.2} Si 6 GeN 10: Eu, Sr 2 Si 5 N 8: Pr, Ba 2 Si 5 N 8: Pr, Sr 2 Si 5 N 8: Tb, BaGe 7 N 10 : Ce (0 <T <1).

  L is at least one Group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. That is, Mg, Ca, Sr, etc. can be used alone as a group II element, or two kinds of combinations such as Ca and Sr, Ca and Mg, Ca and Ba, Ca and Sr and Ba, It may also be a combination of three or more kinds of elements. In particular, by using at least one of Ca and Sr as the Group II element in the composition of the nitride phosphor, a phosphor excellent in emission luminance, quantum efficiency, and the like can be obtained. At least one element of Ca and Sr may be included, and a part of Ca or Sr may be substituted with Be, Mg, Ba, or Zn. When using 2 or more types of mixtures, a compounding ratio can be changed as desired. In the present nitride phosphor, the peak wavelength shifts to the longer wavelength side when Sr and Ca are mixed than when only Sr or Ca is used. When the molar ratio of Sr and Ca is 7: 3 or 3: 7, the peak wavelength is shifted to the long wavelength side compared to the case where only Ca and Sr are used. Furthermore, when the molar ratio of Sr and Ca is approximately 5: 5, the peak wavelength is shifted to the longest wavelength side.

  M is at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. That is, as the group IV element, C, Si, Ge, etc. can be used alone, or C and Si, Ge and Si, Ti and Si, Zr and Si, Ge and Ti and Si, etc. It may be a combination of three or more kinds of elements. In particular, nitride phosphors can be provided at low cost and with good crystallinity by using Si as the Group IV element. In this case, a part of Si may be replaced with C, Ge, Sn, Ti, Zr, and Hf. When Si is contained as an essential component, the blending ratio can be changed as desired. For example, 95% by weight of Si and 5% by weight of Ge can be used as Group IV elements.

R is at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. That is, as rare earth elements, Eu, Pr, Ce and the like can be used alone, or two kinds of combinations such as Ce and Eu, Pr and Eu, La and Eu may be used, and three or more It may be a combination of types. In particular, by using Eu as a rare earth element as an activator, a nitride phosphor having excellent emission characteristics having a peak wavelength in the yellow to red region can be provided. A part of Eu may be replaced with Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Lu. By substituting a part of Eu with another element, the other element acts as a co-activation. By co-activation, the color tone can be changed, and the light emission characteristics can be adjusted. When using a mixture in which Eu is essential, the blending ratio can be changed as desired. In the following examples, europium Eu, which is a rare earth element, is used for the emission center. Europium mainly has bivalent and trivalent energy levels. The phosphor of the present invention uses Eu ²⁺ as an activator with respect to the base alkaline earth metal silicon nitride. Eu ²⁺ is easily oxidized and is commercially available with a trivalent Eu ₂ O ₃ composition. For example, it is preferable to use europium alone or europium nitride.

The nitride phosphor used in the present invention preferably contains boron.
When boron is added, diffusion of Eu ²⁺ is promoted, and emission characteristics such as emission luminance, energy efficiency, and quantum efficiency can be improved. Further, the particle size can be increased, and the light emission characteristics can be improved.

  The nitride phosphor may further include 1 to 500 ppm of at least one group I element selected from the group consisting of Li, Na, K, Rb, and Cs. Since Group I elements are scattered during firing in the production process, the amount added after firing is smaller than the amount added to the raw material. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less. This is because light emission efficiency such as light emission luminance can be adjusted. By adding the Group I element, it is possible to improve the light emission luminance and the quantum efficiency as described above.

  The nitride phosphor further includes a group I element composed of Cu, Ag, Au, a group III element composed of Al, Ga, In, a group IV element composed of Ti, Zr, Hf, Sn, Pb, P 1 to 500 ppm of at least one element selected from Group V elements consisting of Sb, Bi, and Group VI elements consisting of S can also be included. These elements, like the Group I elements, are scattered during firing in the production process, so that the amount added after firing is less than the amount initially added to the raw material. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less. The luminous efficiency can be adjusted by adding these elements.

  The nitride phosphor may further contain 1 or more and 500 ppm or less of any element of Ni and Cr. This is to adjust the afterglow. Therefore, it is preferable to adjust the amount added to the raw material to 1000 ppm or less.

  The elements to be added to the above-described nitride phosphor are usually added as oxides or oxide hydroxides, but are not limited thereto, and are not limited to metals, nitrides, imides, amides, or other inorganic substances. A salt may be sufficient and the state previously contained in the other raw material may be sufficient.

  Oxygen may be contained in the composition of the nitride phosphor. It is conceivable that oxygen is introduced from various oxides as raw materials, or oxygen is mixed during firing. This oxygen is considered to promote the effects of Eu diffusion, grain growth, and crystallinity improvement. That is, even if one compound used as a raw material is replaced with metal, nitride, or oxide, the same effect can be obtained, but rather the effect when using an oxide may be great. The crystal structure of the nitride phosphor may be monoclinic or orthorhombic, but may be non-single crystal or hexagonal.

(Nitride phosphor manufacturing method)
Next, a method for producing ((Sr _X Ca _1-X ) ₂ Si ₅ N ₈ : Eu) will be described as an example of a method for producing a nitride phosphor. In addition, this invention is not limited to the following manufacturing methods. Further, the phosphor may contain Mn and O.
First, 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, Al ₂ O ₃ or the like. Sr and Ca obtained by pulverization preferably have an average particle size of about 0.1 μm to 15 μm. The purity of Sr and Ca is preferably 2N or higher. In order to improve the mixed state, at least one of the metal Ca, the metal Sr, and the metal Eu can be alloyed, nitrided, pulverized, and used as a raw material.

Next, 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. The purity of the raw material Si is preferably 3N or more, but Al ₂ O ₃ , Mg, metal borides (Co ₃ B, Ni ₃ B, CrB), manganese oxide, H ₃ BO ₃ , B ₂ O ₃ , Compounds such as Cu ₂ O and CuO may be contained. Si is also pulverized in the same manner as the raw materials Sr and Ca. The average particle size of the Si compound is preferably about 0.1 μm to 15 μm.

Next, the raw materials Sr and Ca are nitrided in a nitrogen atmosphere. This reaction formula is shown in the following formula 1 and formula 2, respectively.
3Sr + N ₂ → Sr ₃ N ₂ (Formula 1)
3Ca + N ₂ → Ca ₃ N ₂ (Formula 2)
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. Sr and Ca nitrides are preferably of high purity, but commercially available ones can also be used.

The raw material Si is nitrided in a nitrogen atmosphere. This reaction formula is shown in the following formula 3.
3Si + 2N ₂ → Si ₃ N ₄ (Formula 3)
Silicon Si is also nitrided in a nitrogen atmosphere at 800 to 1200 ° C. for about 5 hours. Thereby, silicon nitride is obtained. The silicon nitride used in the present invention is preferably highly pure, but commercially available ones can also be used.

Sr, Ca or Sr—Ca nitride is pulverized.
Similarly, Si nitride is pulverized. Similarly, the Eu compound Eu ₂ O ₃ is pulverized. Europium oxide is used as the Eu compound, but metal europium, europium nitride, and the like can also be used. In addition, as the raw material Z, an imide compound or an amide compound can be used. Europium oxide is preferably highly purified, but commercially available products can also be used. The average particle size of the alkaline earth metal nitride, silicon nitride and europium oxide after pulverization is preferably about 0.1 μm to 15 μm.

The raw material may contain at least one selected from the group consisting of Mg, Sr, Ca, Ba, Zn, B, Al, Cu, Mn, Cr, O, and Ni. In addition, the above elements such as Mg, Zn, and B can be mixed by adjusting the blending amount in the following mixing step. These compounds can be added alone to the raw material, but are usually added in the form of compounds. Such compounds include H ₃ BO ₃ , Cu ₂ O ₃ , MgCl ₂ , MgO · CaO, Al ₂ O ₃ , metal borides (CrB, Mg ₃ B ₂ , AlB ₂ , MnB), B ₂ O ₃ , Cu ₂ O, CuO, and the like.
After the pulverization, Sr, Ca, Sr—Ca nitride, Si nitride, and Eu compound Eu ₂ O ₃ are mixed, and Mn is added.

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. The reaction formula of the base nitride phosphor by this firing is shown in the following formula 4.
(Formula 4)
(X / 3) Sr ₃ N ₂ + ((1.97-X) / 3) Ca ₃ N ₂ + (5/3) Si ₃ N ₄ + (0.03 / 2) Eu ₂ O ₃
→ Sr _X Ca _1.97-X Eu _0.03 Si ₅ N _7.98 O _0.045

As described above, a nitride phosphor represented by (Sr _X Ca _1-X ) ₂ Si ₅ N ₈ : Eu can be manufactured.
Nitride phosphors with other compositions can be produced by changing the selection of raw materials and the blending ratio.
The firing temperature can be in the range of 1200 to 1700 ° C, but the firing temperature is preferably 1400 to 1700 ° C. It is preferable to use a one-step baking in which the temperature is gradually raised and the baking is performed at 1200 to 1500 ° C. for several hours, but the first baking is performed at 800 to 1000 ° C. and the heating is gradually started from 1200. Two-stage firing (multi-stage firing) in which the second stage firing is performed at 1500 ° C. can also be used. 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.

By using the above manufacturing method, it is possible to obtain a target phosphor.
As described above, the nitride phosphor of the first embodiment described above can adjust the excitation spectrum and the emission spectrum within a relatively wide range depending on its composition, and a desired amber-colored light emitting device by combining with the YAG phosphor. Can be configured.
In addition, it is possible to select a composition that suppresses a color shift caused by a change in the emission wavelength of the light emitting element, which may occur when the light emitting device is configured using two types of phosphors.

The nitride phosphor preferably contains 1 ppm or more and 10000 ppm or less of B in order to increase the light emission luminance. In order to contain boron, for example, each starting raw material in manufacturing is used. A boron compound may be added together. Alternatively, it can be contained in advance in a raw material composition such as Ca ₃ N ₂ or Si ₃ N ₄ . For example, in wet mixing, when H ₃ BO ₃ is added separately from the raw material, it is preferably set to 1 ppm or more and 1000 ppm or less, and more preferably 100 ppm or more and 1000 ppm or less. In the dry mixing, when boron is added, it is preferably set to 1 ppm or more and 10,000 ppm or less, more preferably 100 ppm or more and 10,000 ppm or less. The boron acts as a flux.
Boron, boride, boron nitride, boron oxide, borate, etc. can be used as boron added to the raw material. Specific examples include BN, H ₃ BO ₃ , B ₂ O ₆ , B ₂ O ₃ , BCl ₃ , SiB ₆ , and CaB ₆ . A predetermined amount of these boron compounds is weighed and added to the raw material. The amount of boron added to the raw material does not necessarily match the boron content after firing. Since boron partially scatters at the firing stage in the manufacturing process, the boron content after firing is less than when added to the raw material.

The YAG phosphor described above can freely adjust the chromaticity in the range from green to yellow by selecting the composition and composition ratio, and can adjust the excitation spectrum and excitation efficiency in a relatively wide range.
In addition, the nitride phosphor can freely adjust the chromaticity in the yellow-red range by selecting the composition and composition ratio, and can adjust the excitation spectrum and excitation efficiency in a relatively wide range.
Therefore, the composition and composition ratio are adjusted so that a desired amber color can be obtained by combining a YAG phosphor whose composition and composition ratio have been adjusted so as to obtain a predetermined chromaticity, and the YAG phosphor. By combining the nitride phosphor with an appropriate range, a predetermined amber color can be realized.

(Coating material)
The coating member 12 (light transmissive material) is provided in the cup of the lead frame 13 and is used by mixing with the phosphor 11 that converts the light emission of the light emitting element 10. Specific materials for the coating member 12 include a transparent resin excellent in temperature characteristics and weather resistance such as epoxy resin, urea resin, and silicone resin, a translucent inorganic material generated by a sol-gel method from a metal alkoxide, glass, inorganic A binder or the like is used. In addition to the phosphor 11, a diffusing agent, barium titanate, titanium oxide, aluminum oxide, or the like may be included. Moreover, you may contain a light stabilizer and a coloring agent.

(Ratio of coating material to phosphor)
In the first embodiment, by setting the amount of the phosphor contained in the coating member to 15 wt% or more, the output of the blue light of the light emitting element to the outside is suppressed, and the emission color is substantially emitted only by the phosphor. It is determined by the light to be.
Specifically, when the amount of the phosphor is 15 weight percent of the coating member, the amount of light emitted from the light emitting element directly to the outside is 10% with respect to the total luminous flux. As described above, when the amount of light directly emitted from the light emitting element is 10% or less, the light emitting color is substantially determined only by the light emission of the phosphor, and a light emitting device capable of amber light emission is obtained. Can do.

<Light emitting element>
In the light emitting element of the first embodiment, for example, a substrate 1 made of sapphire, a semiconductor layer 2 formed thereon, and positive and negative electrodes formed on the same plane side of the semiconductor layer 2 are formed. The semiconductor layer 2 includes a plurality of layers including a light emitting layer (not shown), and blue light is output from the light emitting layer.
Examples of the material of the semiconductor light emitting device capable of emitting light of 500 nm or less in the ultraviolet to blue region include various semiconductors such as BN, SiC, ZnSe, GaN, InGaN, InAlGaN, AlGaN, BAlGaN, and BInAlGaN. These elements can contain Si, Zn, or the like as an impurity element to serve as a light emission center. As a material particularly suitable 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 phosphor, a nitride semiconductor (for example, a nitride semiconductor containing Al or Ga, In or Ga, etc.) _{In X Al Y Ga 1-X} -Y N, 0 <X <1,0 <Y <1, X + Y ≦ 1) is mentioned as a nitride semiconductor containing.

  As a preferable structure of the light-emitting element, a homostructure having a MIS junction, a PIN junction, a pn junction, or the like, a heterostructure, or a double heterostructure can be given. In the semiconductor light emitting device, various emission wavelengths can be selected depending on the material of the semiconductor layer 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 active layer is formed in a thin film in which a quantum effect is generated.

  When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, GaAs, or GaN is preferably used as the 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 grown on the sapphire substrate by HVPE method, MOCVD method or the like. In this case, preferably, a buffer layer made of GaN, AlN, GaAIN or the like is grown on the sapphire substrate at a low temperature to form a non-single crystal, and a nitride semiconductor having a pn junction is formed thereon.

Examples of light-emitting elements that can efficiently emit light in the ultraviolet region having a pn junction using a nitride semiconductor include the following structures.
In the structure example, first, SiO ₂ is formed in a stripe shape on the buffer layer substantially perpendicular to the orientation flat surface of the sapphire substrate. Next, GaN is grown on the stripes by HVPE using ELOG (Epitaxial Lateral Over Grows GaN). Subsequently, by MOCVD, 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 Double the 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. Configure the heterostructure. In this structure, the active layer can be formed into a ridge stripe shape and sandwiched between guide layers, and a resonator end face can be provided to provide a semiconductor laser device that can be used in the present invention.

  Nitride semiconductors exhibit n-type conductivity without being doped with impurities, but it is preferable to form an n-type nitride semiconductor having a predetermined carrier concentration for the purpose of improving luminous efficiency. Si, Ge, Se, Te, C, etc. are introduced as appropriate as n-type dopants. On the other hand, when forming a p-type nitride semiconductor, the p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to lower the resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. When forming the positive and negative electrodes while leaving the sapphire substrate as it is, a part of the p-type side is etched to the surface of the first contact layer, and both the p-type and n-type contact layers are formed on the same surface side. Expose. And after forming an electrode on each contact layer, the nitride semiconductor light emitting device (chip) is manufactured by cutting the wafer into chips.

In the first embodiment, a blue light emitting element is used. However, when a translucent resin is used as a coating member or a mold member, the excitation wavelength of the nitride phosphor and the deterioration of the translucent resin are reduced. Considering both, it is preferable to set the emission wavelength of the light emitting element to 450 nm or more and 470 nm or less.
In addition, in the light emitting device according to the present invention, when a device other than a blue light emitting element is used as in the second embodiment described later, both the excitation wavelength of the nitride phosphor and the deterioration of the translucent resin are considered. The emission wavelength of the light emitting element is preferably set so that the main emission wavelength is 360 nm or more and 420 nm or less.

Further, in the semiconductor light emitting device, the sheet resistance Rn of the n-type contact layer formed with an impurity concentration of 10 ¹⁷ to 10 ²⁰ / cm ³ and the sheet resistance Rp of the translucent p electrode have a relationship of Rp ≧ Rn. It is preferable that the adjustment is performed. For example, the n-type contact layer is preferably formed to a thickness of 3 to 10 μm, more preferably 4 to 6 μm, and its sheet resistance Rn is estimated to be 10 to 15Ω / □. It is good to form in a thin film so that it may have a sheet resistance value more than a value. Specifically, the translucent p-electrode is preferably formed of a thin film having a thickness of 150 μm or less. Moreover, ITO other than a metal and ZnO can also be used for a p electrode. Here, instead of the translucent p-electrode, an electrode having a plurality of light extraction openings such as a mesh electrode can also be used.

  Further, when the translucent p-electrode is formed of a multilayer film or alloy composed of one kind selected from the group of gold and platinum group elements and at least one other element, it is contained. When the sheet resistance of the translucent p-electrode is adjusted by the content of the gold or platinum group element, stability and reproducibility are improved. Since gold or a metal element has a high absorption coefficient in the wavelength region of the semiconductor light emitting device used in the present invention, the smaller the amount of gold or platinum group element contained in the translucent p-electrode, the better the transparency. In the conventional semiconductor light emitting device, the relationship of sheet resistance is Rp ≦ Rn. However, in the present invention, Rp ≧ Rn, and therefore the translucent p-electrode is formed in a thin film as compared with the conventional one. However, thinning can be easily performed by reducing the content of gold or platinum group elements.

  As described above, in the semiconductor light emitting device used in the present invention, the sheet resistance RnΩ / □ of the n-type contact layer and the sheet resistance RpΩ / □ of the translucent p-electrode form a relationship of Rp ≧ Rn. Preferably it is. It is difficult to measure Rn after it is formed as a semiconductor light emitting device, and it is practically impossible to know the relationship between Rp and Rn, but what is the relationship between Rp and Rn from the state of the light intensity distribution during light emission? You can know if they are in a relationship.

  When the translucent p-electrode and the n-type contact layer have a relationship of Rp ≧ Rn, providing a p-side pedestal electrode in contact with the translucent p-electrode and having an extended conductive portion further improves external quantum efficiency. Can be achieved. There is no limitation on the shape and direction of the extended conductive portion, and when the extended conductive portion is on the satellite, it is preferable because the area for blocking light is reduced, but a mesh shape may be used. Further, the shape may be a curved shape, a lattice shape, a branch shape, or a hook shape in addition to the straight shape. At this time, since the light shielding effect increases in proportion to the total area of the p-side pedestal electrode, it is preferable to design the line width and length of the extended conductive portion so that the light shielding effect does not exceed the light emission enhancing effect.

(Lead frame)
The lead frame 13 includes a mount lead 13a and an inner lead 13b.

  The mount lead 13a has a cup in which the light emitting element 10 is disposed. A plurality of light emitting elements 10 can be arranged in the cup of the mount lead 13 a and the mount leads 13 a can be used as a common electrode for the plurality of light emitting elements 10. In this case, sufficient electrical conductivity and connectivity with the conductive wire 14 are required. Die bonding (adhesion) between the light emitting element 10 and the cup of the mount lead 13a can be performed with a thermosetting resin or the like. Examples of the thermosetting resin include an epoxy resin, an acrylic resin, and an imide resin. Further, as a face-down structure, Ag paste, carbon paste, metal bump, or the like can be used for die-bonding the light emitting element 10 and the mount lead 13a and making electrical connection. An inorganic binder can also be used.

  The inner lead 13 b is electrically connected to the other electrode 3 of the light emitting element 10 disposed on the mount lead 13 a by the conductive wire 14. The inner lead 13b is disposed at a position away from the mount lead 13a in order to avoid a short circuit due to electrical contact with the mount lead 13a. When a plurality of light emitting elements 10 are provided on the mount lead 13a, it is necessary to configure the wire bonding so that the conductive wires do not contact each other. The inner lead 13b is preferably made of the same material as that of the mount lead 13a, and iron, copper, iron-containing copper, gold, platinum, silver, or an alloy thereof can be used.

(Conductive wire)
The conductive wire 14 electrically connects the electrode 3 of the light emitting element 10 and the lead frame 13. The conductive wire 14 preferably has good ohmic properties, mechanical connectivity, electrical conductivity, and thermal conductivity with the electrode 3. Specific materials for the conductive wire 14 are preferably metals such as gold, copper, platinum, and aluminum, and alloys thereof.

(Mold member)
The mold member 15 is provided to protect the light emitting element 10, the phosphor 11, the coating member 12, the lead frame 13, the conductive wire 14, and the like from the outside. In addition to the purpose of protection from the outside, the mold member 15 also has the purposes of widening the viewing angle, relaxing the directivity from the light emitting element 10, and converging and diffusing the emitted light. The mold member can have a shape suitable for achieving these purposes. For example, the mold member 15 may have a structure in which a plurality of layers are stacked in addition to a convex lens shape and a concave lens shape. As a specific material of the mold member 15, a translucent inorganic material produced by a sol-gel method from an epoxy resin, a urea resin, a silicone resin, a metal alkoxide, or the like, a glass or the like has excellent translucency, weather resistance and temperature characteristics Material can be used. The mold member 15 can contain a diffusing agent, a colorant, an ultraviolet absorber, and a phosphor. As the diffusing agent, barium titanate, titanium oxide, aluminum oxide or the like is preferable. In order to reduce the resilience of the material with the coating member 12, it is preferable to use the same material in consideration of the refractive index.

Embodiment 2. FIG.
The light emitting device according to the second embodiment of the present invention considers the excitation wavelength dependency of the excitation efficiency of the nitride phosphor and the excitation wavelength dependency of the excitation efficiency of the YAG phosphor in the light emitting device of the first embodiment. By setting the composition and composition ratio of the nitride phosphor and the composition and composition ratio of the YAG phosphor, the color shift due to the variation in the emission wavelength of the light emitting element is prevented.
That is, when the light emitting device is configured using two types of phosphors as in the first embodiment, when the wavelength dependence of the excitation efficiency of the two phosphors is different due to the variation in the emission wavelength of the light emitting element, The light mixing ratio changes, and the emission color changes.
However, in the light emitting device of the second embodiment, even when the emission wavelength of the light emitting element changes, the excitation efficiency of the nitride phosphor and the excitation efficiency of the YAG phosphor change in the same way, The composition of the nitride phosphor and the YAG phosphor is set so that the light mixing ratio is always kept constant within the fluctuation range of the emission wavelength.

  Specifically, in the light-emitting device of Embodiment 1, the peak wavelength of the light-emitting element that excites the phosphor is long when the current value input to the light-emitting element is small, and the peak value of the current input to the light-emitting element is large. Will be shorter. Therefore, in the second embodiment, in consideration of the change in the emission wavelength due to the current value of the light emitting element, the peak wavelength of the excitation absorption spectrum of the YAG phosphor is higher than the peak wavelength of the light emitting element when the input current value is low. Set to short wavelength side. Preferably, the peak wavelength of the light emitting element when the current input to the light emitting element is maximized is substantially matched with the peak wavelength of the excitation absorption spectrum of the YAG phosphor. In this way, the YAG phosphor can be excited efficiently.

The group and composition ratio of the nitride phosphors are set so that the peak wavelength of the excitation absorption spectrum of the nitride phosphor is located on the shorter wavelength side than the peak wavelength of the light emitting device when the input current value is low. In this case, preferably, in order to efficiently excite the nitride phosphor, the peak wavelength of the light emitting element when the current input to the light emitting element is maximized and the peak wavelength of the excitation absorption spectrum of the nitride phosphor are A set of nitride phosphors and a composition ratio are set so as to substantially match.
In this way, when the composition and composition ratio of the YAG phosphor and the nitride phosphor are set, an amber light emitting device with little color shift can be realized.

Hereinafter, the mechanism for preventing color misregistration in the second embodiment will be described using a phosphor having a specific composition as an example.
First, as shown in FIG. 2, the peak wavelength of the semiconductor light emitting element is shifted to the short wavelength side by increasing the input current. This is because when the input current is increased, the current density is increased and the band gap is increased. The variation between the peak wavelength of the emission spectrum when the current density to the light emitting element is small and the peak wavelength of the emission spectrum when the input current is increased is, for example, about a change in the input current from 20 mA to 100 mA. It is about 10 nm (FIG. 2).

On the other hand, for example, the peak wavelength in the excitation spectrum of the YAG phosphor represented by Y ₃ (Al _0.8 Ga _0.2 ) ₅ O ₁₂ : Ce (phosphor 3 in FIG. 3) is about 448 nm. However, when the emission intensity when excited with light having a peak wavelength of 448 nm in the excitation spectrum is 100, the emission intensity when excited with light having a wavelength of 460 nm is 95. Further, in the YAG phosphor, the emission intensity changes substantially linearly with respect to light having a wavelength in the range of 448 nm to 460 nm.

On the other hand, for example, the peak wavelength in the excitation spectrum of the nitride phosphor represented by (Sr _0.579 Ca _0.291 Eu _0.03 ) ₂ Si ₅ N ₈ is about 450 nm. When the emission intensity at 450 nm is 100, the emission intensity at 460 nm is 95 (shown as phosphor 5 in FIG. 4). Further, the emission intensity of the nitride phosphor changes substantially linearly with respect to light in the range of 448 nm to 460 nm.
Therefore, when an element having an emission peak wavelength of 460 nm immediately after the current is input (for example, at a current value as low as about 20 mA) is selected as the light emitting element, the input current is increased in the light emitting element to obtain a current of 100 mA. In this case, the emission peak wavelength is about 450 nm. However, the excitation efficiency of the nitride phosphor and the excitation efficiency of the YAG phosphor are different when excited with light having a wavelength of 460 nm and excited with light having a wavelength of 450 nm. There is no change in the ratio.

Accordingly, when the current input amount of the light emitting element is increased from 20 mA to 100 mA, the change amount of the emission intensity of the YAG phosphor and the change amount of the emission intensity of the nitride phosphor with respect to the change of the emission wavelength of the light emitting element are equal. Become.
As a result, even when the emission peak wavelength changes due to the amount of input current in the light emitting element, the ratio of the emission intensity of the YAG phosphor and the emission intensity of the nitride phosphor can be made constant, and the occurrence of color shift is eliminated. Can do.
Note that when the current input amount of the light emitting element is increased from 20 mA to 100 mA, for example, the light emission intensity of the light emitting element increases, and the light emission intensity of the YAG phosphor and the light emission intensity of the nitride phosphor increase. The emission intensity ratio between the YAG phosphor and the nitride phosphor is kept constant. Therefore, although the light emission intensity as a whole of the light emitting device is increased, no color shift occurs.

  As described above, according to the light emitting device of the second embodiment, even when used as a dimmable illumination light source, illumination without color misregistration can be achieved, and light is emitted in the case of pulse driving and continuous light emission. The color never changes.

Embodiment 3 FIG.
The light emitting device according to the third embodiment of the present invention is nitrided in consideration of the temperature dependency of the emission intensity of the nitride phosphor and the temperature dependency of the emission intensity of the YAG phosphor in the light emitting device of the first embodiment. Color misregistration is prevented by setting the composition and composition ratio of the phosphor and the composition and composition ratio of the YAG phosphor.

  That is, in the third embodiment, the respective compositions and composition ratios are preferably set so that the changes in emission intensity accompanying changes in the ambient temperature of the respective phosphors are substantially equal to each other. This is to prevent color misregistration due to a change in ambient temperature of the phosphor due to a change in use environment temperature or heat generation of the light emitting element. That is, if the temperature dependence of the emission intensity is different, the emission intensity ratio between the phosphors varies due to the change in the ambient temperature, resulting in a color shift.

In general, since the excitation efficiency of the phosphor decreases as the ambient temperature increases, the output of light emitted from the phosphor also decreases, but it is needless to say that the rate of decrease is small.
In the first embodiment, the decrease rate of the relative light emission output when the ambient temperature is changed by 1 ° C. is defined as the light emission output decrease rate, and the light emission output decrease rates of two or more phosphors are both 4.0 × 10. ^-3 [a. u. / ° C.] or less, preferably 3.0 × 10 ⁻³ [a. u. / ° C.] or less, more preferably 2.0 × 10 ⁻³ [a. u. / ° C.] The composition of the phosphor is adjusted so as to be below. Thereby, it is possible to further suppress the decrease in the luminous flux [lm] of the entire light emitting device that generates heat as compared with the conventional case. Therefore, in the first embodiment, the light emission output decrease rate is adjusted within the above-described range, and the light emission output decrease rate with respect to the temperature increase of two or more phosphors is substantially equal. By doing so, the temperature characteristics of the phosphors whose excitation efficiency decreases due to heat generation are substantially the same, and a light emitting device capable of suppressing the occurrence of color misregistration even when the ambient temperature changes can be formed.

Embodiment 4 FIG.
The light emitting device according to Embodiment 4 of the present invention is the same as that of Embodiment 1 except that (1) a light emitting element that emits ultraviolet light is used instead of a blue light emitting element, and (2) a YAG phosphor is used. The configuration is the same as in the first embodiment except that an oxynitride phosphor is used.
That is, the light-emitting device of the fourth embodiment is characterized in that a light-emitting element that emits ultraviolet light, a nitride phosphor, and an oxynitride phosphor are combined. A desired amber color is realized by the color mixture of the luminescent color with the oxynitride phosphor.

In the light emitting device of the fourth embodiment, the excitation efficiency and oxynitridation of the nitride phosphor with respect to fluctuations in the emission wavelength of the light emitting element that emits ultraviolet light, as in the second embodiment. It is preferable that the excitation efficiency of the fluorescent substance is changed at the same rate, thereby preventing color shift.
For example, the nitride phosphor represented by (Ca _0.985 Eu _0.015 ) ₂ Si ₅ N ₈ has an excitation spectrum peak wavelength of about 370 nm, and the excitation efficiency decreases when the wavelength becomes longer than the peak wavelength. . Moreover, the peak wavelength in the excitation spectrum of the oxynitride phosphor represented by CaSi ₂ O ₂ N ₂ : Eu is about 370 nm, and the excitation efficiency decreases as the wavelength becomes longer than the peak wavelength.
The rate of decrease in excitation efficiency can be made substantially the same by appropriately selecting the composition of the nitride phosphor and the oxynitride phosphor.

Therefore, when an element having an emission peak wavelength of 380 nm immediately after supplying current (for example, at a current value as low as about 20 mA) is selected as the light emitting element, the light emission of the nitride phosphor with respect to the change in the emission wavelength of the light emitting element. The amount of change in intensity and the amount of change in emission intensity of the oxynitride phosphor can be made substantially equal.
In the present embodiment, the peak wavelength in the excitation spectrum of the nitride phosphor and the peak wavelength in the excitation spectrum of the oxynitride phosphor are selected by appropriately selecting each composition, so that the shorter wavelength side or the longer wavelength side. And can be adjusted according to the wavelength of the light emitting element to be selected.

In the present invention, the peak wavelength in the excitation spectrum of the nitride phosphor and the peak wavelength in the excitation spectrum of the oxynitride phosphor are preferably matched, but the present invention is not limited to this.
As described above, according to the light emitting device of the fourth embodiment, an amber light emitting device can be realized using a light emitting element that emits ultraviolet light.
Since the amber light emitting device of the fourth embodiment is configured using a light emitting element that emits ultraviolet light, the light emitted from the light emitting element is emitted to the outside as in the case of the first embodiment. It is not necessary to suppress it.

  In addition, by considering the excitation wavelength dependency of the excitation efficiency of the nitride phosphor and the excitation wavelength dependency of the excitation efficiency of the oxynitride phosphor, light emission with less color shift is selected by selecting each composition and composition ratio. Equipment can be provided. Further, by optimizing the composition, it is possible to substantially match the temperature characteristics of the nitride phosphor and the oxynitride phosphor, thereby preventing color shift.

Hereinafter, the oxynitride phosphor will be described in detail.
The oxynitride phosphor according to the fourth embodiment uses a rare earth element as an activator, and is a group II which is at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. The phosphor includes an oxynitride phosphor crystal containing at least one element and at least one group IV element selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. .
Here, the oxynitride phosphor crystal is, for example, an oxynitride phosphor made of a crystal belonging to an orthorhombic crystal shown in an example described later.
The combinations of the group II elements and group IV elements listed above are arbitrary, but those having the following compositions are preferably used.

The oxynitride phosphor of the preferred embodiment 4 has the general formula L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _{X M Y Q T O Z N (} (2/3) X + (4/3) Y + T- (2/3) Z): represented by the general formula of R. Here, L is a Group II element that is at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. M is a Group IV element that is at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. Q is a Group III element that is at least one selected from the group consisting of B, Al, Ga, and In. O is an oxygen element. N is a nitrogen element. R is a rare earth element. 0.5 <X <1.5, 1.5 <Y <2.5, 0 <T <0.5, 1.5 <Z <2.5.

  The oxynitride phosphor represented by the general formula can include a crystal in which elements are arranged at least partially according to a certain rule, and high-luminance light is efficiently emitted from the crystal. In the above general formula, by setting 0.5 <X <1.5, 1.5 <Y <2.5, 0 <T <0.5, 1.5 <Z <2.5, the light emitting part Therefore, it is possible to provide a phosphor with high luminance and high luminance.

In the above general formula, X, Y, and Z are preferably X = 1, Y = 2, and Z = 2. With this composition, more crystal phases are formed and the crystallinity thereof is increased. The luminous efficiency and luminance can be increased. The proportion of crystals (crystal phase) contained in the oxynitride phosphor of the fourth embodiment is preferably 50% by weight or more, more preferably 80% by weight or more.
For the purpose of adjusting the light emission luminance and the like, when it is desired to set the ratio of contained crystals to a desired value, it can be adjusted by the values of X, Y, and Z in the above general formula.
However, the above range is a preferable range, and the present invention is not limited to the above range.

Specifically, the oxynitride phosphor of the present invention includes CaSi ₂ O ₂ N ₂ : Eu, SrSi ₂ O ₂ N ₂ : Eu, BaSi ₂ O ₂ N ₂ : Eu, ZnSi ₂ O ₂ N ₂ : Eu, CaGe ₂ O ₂ N ₂ : Eu, SrGe ₂ O ₂ N ₂ : Eu, BaGe ₂ O ₂ N ₂ : Eu, ZnGe ₂ O ₂ N ₂ : Eu, Ca _0.5 Sr _0.5 Si ₂ O ₂ N ₂ : Eu, Ca _0.5 Ba _0.5 Si ₂ O ₂ N ₂ : Eu, Ca _0.5 Zn _0.5 Si ₂ O ₂ N ₂ : Eu, Ca _0.5 Be _0.5 Si ₂ O ₂ N ₂ : Eu, Sr _0.5 Ba _0.5 Si ₂ O ₂ N ₂ : Eu, Ca _0.8 Mg _0.2 Si ₂ O ₂ N ₂ : Eu, Sr _0.8 Mg _0.2 Si _{2 O 2 N 2: Eu, Ca} 0.5 Mg 0.5 Si 2 O 2 N 2: E _{, Sr 0.5 Mg 0.5 Si 2 O} 2 N 2: Eu, CaSi 2 B 0.1 O 2 N 2: Eu, SrSi 2 B 0.1 O 2 N 2: Eu, BaSi 2 B 0.1 O ₂ N ₂ : Eu, ZnSi ₂ B _0.1 O ₂ N ₂ : Eu, CaGe ₂ B _0.01 O ₂ N ₂ : Eu, SrGe ₂ Ga _0.01 O ₂ N ₂ : Eu, BaGe ₂ In _{0 .01 O 2 N 2: Eu,} ZnGe 2 Al 0.05 O 2 N 2: Eu, Ca 0.5 Sr 0.5 Si 2 B 0.3 O 2 N 2: Eu, CaSi 2.5 O 1. ₅ N ₃ : Eu, SrSi _2.5 O _1.5 N ₃ : Eu, BaSi _2.5 O _1.5 N ₃ : Eu, Ca _0.5 Ba _0.5 Si _2.5 O _1.5 N _{3 : Eu, Ca 0.5 Sr 0.5 Si} 2.5 O 1.5 N 3: Eu, _{a 1.5 Si 2.5 O 2.5 N 2.7} : Eu, Sr 1.5 Si 2.5 O 2.5 N 2.7: Eu, Ba 1.5 Si 2.5 O 2.5 N _2.7 : Eu, Ca _1.0 Ba _0.5 Si _2.5 O _1.5 N ₃ : Eu, Ca _1.0 Sr _0.5 Si _2.5 O _1.5 N ₃ : Eu, Ca _0.5 Si _1.5 O _1.5 N _1.7 : Eu, Sr _0.5 Si _1.5 O _1.5 N _1.7 : Eu, Ba _0.5 Si _1.5 O _1.5 N _1.7 : Eu, Ca _0.3 Ba _0.2 Si _2.5 O _1.5 N ₃ : Eu, Ca _0.2 Sr _0.3 Si _2.5 O _1.5 N ₃ : represented by Eu, etc. Oxynitride phosphors are included.

Further, as shown here, the oxynitride phosphor of the fourth embodiment can change the ratio of O and N, and the color tone and brightness can be adjusted by changing the ratio. Can do. Further, the molar ratio of the cation and the anion represented by (L + M) / (O + N) can be changed, whereby the emission spectrum and intensity can be finely adjusted. This can be achieved, for example, by performing a process such as vacuum to desorb N and O, but the present invention is not limited to this method. The composition of the oxynitride phosphor may contain at least one of Li, Na, K, Rb, Cs, Mn, Re, Cu, Ag, and Au. The light emission efficiency such as quantum efficiency can be adjusted. Further, other elements may be included so as not to impair the characteristics.
Part of the Group II element contained in the oxynitride phosphor is replaced with the activator R. The amount of the activator R with respect to the mixed amount of the Group II element and the activator R is (the mixed amount of the Group II element and the activator R): (the amount of the activator R). It is preferable that the molar ratio is 1: 0.001 to 1: 0.8.

  L is a Group II element that is at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, and Zn. In the present invention, L may be a simple substance such as Ca and Sr, but may be composed of a combination of a plurality of elements such as Ca and Sr, Ca and Ba, Sr and Ba, and Ca and Mg. Further, when L is a combination of a plurality of elements, the composition ratio can be changed. For example, the mixture ratio of Sr and Ca can be changed as desired.

In particular, L is preferably a Group II element that is at least one or more of Ca, Sr and Ba selected from the group consisting of Mg, Ca, Sr, Ba and Zn.
M is a Group IV element that is at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. M may be a single element of Si, Ge, or a combination of a plurality of elements such as Si and Ge or Si and C. In the present invention, the above-mentioned group IV elements can be used, but it is particularly preferable to use Si or Ge. By using Si or Ge, an inexpensive phosphor with good crystallinity can be provided.

In particular, M is preferably a Group IV element that is at least one or more of Si, which is essentially selected from the group consisting of C, Si, Ge, Sn, Ti, and Hf.
R is a rare earth element. Specifically, R is one or more elements selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lr. In the present invention, among these rare earth elements, Eu is preferably used. Further, Eu and at least one element selected from rare earth elements may be included. In that case, as R, it is preferable that Eu is contained by 50% by weight or more, more preferably 70% or more. That is, the activator R is at least one or more types including Eu selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lr. A certain rare earth element is preferable. This is because elements other than Eu act as a co-activator.

In the fourth embodiment, europium Eu, which is a rare earth element, is used for the emission center. Europium mainly has bivalent and trivalent energy levels. In the phosphor of the fourth embodiment, Eu ²⁺ is used as an activator with respect to the base alkaline earth metal silicon nitride. Eu ²⁺ is easily oxidized and is generally commercially available with a trivalent Eu ₂ O ₃ composition.
In this specification, a case where Eu, which is a representative example, is used as the emission center may be described, but the present invention is not limited to this.

As the base material, each of the main components L and M can also be used. For these main components L and M, metals, oxides, imides, amides, nitrides and various salts can be used. In addition, the main components L and M may be mixed and used in advance.
Q is a Group III element that is at least one selected from the group consisting of B, Al, Ga, and In. As Q, metals, oxides, imides, amides, nitrides, various salts, and the like can be used. For example, B ₂ O ₆ , H ₃ BO ₃ , Al ₂ O ₃ , Al (NO ₃ ) ₃ .9H ₂ O, AlN, GaCl ₃ , InCl _{3 and the} like.

L nitride, M nitride, and M oxide are mixed as a base material. In the base material, an oxide of Eu is mixed as an activator. These are weighed to obtain a desired phosphor composition and mixed until uniform. In particular, the base material L nitride, M nitride, and M oxide are 0.5 <L nitride <1.5, 0.25 <M nitride <1.75,2. It is preferable that the oxides are mixed in a molar ratio of 25 <M oxide <3.75. That is, these base _{materials, L X M Y O Z N} ((2/3) X + Y- (2/3) Z-α): R or _{L X M Y Q T O Z} N ((2/3) _{X + Y + T− (2/3) Z−α)} : A predetermined amount is weighed and mixed so as to have a composition ratio of R.

(Method for producing oxynitride phosphor)
Next, a method for producing the oxynitride phosphor, CaSi ₂ O ₂ N ₂ : Eu, according to the fourth embodiment will be described. In addition, this invention is not limited to the following manufacturing methods.
First, Ca nitride, Si nitride, Si oxide, and Eu oxide are prepared. It is better to use purified materials, but commercially available materials may be used.

1. Preparation of Ca nitride First, raw material Ca is pulverized. As the raw material Ca, it is preferable to use a simple substance, but compounds such as an imide compound, an amide compound, and CaO can also be used. The raw material Ca may contain B, Ga, or the like. The raw material Ca is pulverized in a glove box in an argon atmosphere. Ca obtained by pulverization preferably has an average particle diameter of about 0.1 μm to 15 μm, but is not limited to this range. The purity of Ca is preferably 2N or higher, but is not limited thereto.
Next, the pulverized raw material Ca is nitrided in a nitrogen atmosphere. The nitride of Ca can be obtained by nitriding pulverized Ca in a nitrogen atmosphere at 600 to 900 ° C. for about 5 hours. This reaction formula is shown in Formula 5.
(Formula 5)
3Ca + N ₂ → Ca ₃ N ₂
Needless to say, a high-purity Ca nitride is preferable. A commercially available Ca nitride can also be used.
Next, the Ca nitride is pulverized. Ca nitride is pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere.

2. Preparation of Si Nitride First, 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, Ca ₂ Si, SiC, or the like. The purity of the raw material Si is preferably 3N or higher, but may contain B, Ga and the like. Si is also pulverized in a glove box in an argon atmosphere or a nitrogen atmosphere as in the case of the raw material Ca. The average particle size of the Si compound is preferably about 0.1 μm to 15 μm.
The raw material Si is nitrided in a nitrogen atmosphere. Silicon nitride can be obtained by nitriding silicon Si in a nitrogen atmosphere at 800 to 1200 ° C. for about 5 hours. This reaction formula is shown in Formula 6.
(Formula 6)
3Si + 2N ₂ → Si ₃ N ₄
Needless to say, the silicon nitride used in the present invention is preferably of high purity. A commercially available silicon nitride may be used.

Next, the Si nitride is pulverized.
3. Preparation of Si Oxide Commercially available SiO ₂ is used as Si oxide (Silicon Dioxide 99.9%, 190-09072, manufactured by Wako Pure Chemical Industries, Ltd.).
The raw materials (Ca nitride, Si nitride, Si oxide, Eu oxide) purified or manufactured as described above are weighed to a predetermined molar amount.
Then, the weighed raw materials are mixed.
Next, a mixture of Ca nitride, Si nitride, Si oxide, and Eu oxide is fired at about 1500 ° C. in an ammonia atmosphere. The fired mixture is put into a crucible and fired.
By mixing and firing, an oxynitride phosphor represented by CaSi ₂ O ₂ N ₂ : Eu can be obtained. The reaction formula of the basic constituent elements by this firing is shown in Formula 7.
(Formula 7)
(1/3) Ca ₃ N ₂ + (1/3) Si ₃ N ₄ + SiO ₂ + aEu ₂ O ₃
→ CaSi ₂ O ₂ N ₂ : Eu
However, this composition is a representative composition estimated from the blending ratio, and has sufficient characteristics to withstand practical use in the vicinity of the ratio. Moreover, 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 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.
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, it is possible to obtain a target oxynitride phosphor.
Incidentally, B _Ca X _Si containing _{Y B T O Z N ((} 2/3) X + Y + T- (2/3) Z-α): oxynitride represented by Eu phosphor as follows manufacturing can do.
In advance, Eu compound is dry-mixed with B compound H ₃ BO ₃ . Europium oxide is used as the Eu compound, but metal europium, europium nitride, and the like can be used in the same manner as the other constituent elements described above. In addition, an imide compound or an amide compound can also be used as the raw material Eu. Europium oxide is preferably highly purified, but commercially available products can also be used. The compound of B is dry mixed, but can also be wet mixed. Since some of these mixtures are easily oxidized, they are mixed in a glove box in an Ar atmosphere or a nitrogen atmosphere.

The production method of the oxynitride phosphor will be described by taking the compound H ₃ BO ₃ of B as an example. Component constituent elements other than B include Li, Na, K, etc., and these compounds, for example, LiOH. H ₂ O, Na ₂ CO ₃ , K ₂ CO ₃ , RbCl, CsCl, Mg (NO ₃ ) ₂ , CaCl ₂ .6H ₂ O, SrCl ₂ .6H ₂ O, BaCl ₂ .2H ₂ O, TiOSO ₄ .H ₂ O, ZrO (NO ₃ ) ₂ , HfCl ₄ , MnO ₂ , ReCl ₅ , Cu (CH ₃ COO) ₂ .H ₂ O, AgNO ₃ , HAuCl ₄ .4H ₂ O, Zn (NO ₃ ) ₂ .6H _{2 O,} it can be used _{GeO 2, Sn (CH 3 COO} ) 2 or the like.

Grind the mixture of Eu and B. The average particle size of the mixture of Eu and B after pulverization is preferably about 0.1 μm to 15 μm.
After the above pulverization, Ca nitride, Si nitride, Si oxide, and Eu oxide containing B are substantially the same as the manufacturing process of CaSi ₂ O ₂ N ₂ : Eu described above. Mix. After the mixing, firing is performed to obtain the target oxynitride phosphor.

The oxynitride phosphor of the fourth embodiment described above has the same or better stability as the YAG phosphor and has the following characteristics.
(1) The oxynitride phosphor of the fourth embodiment can set a desired emission color in a relatively wide range from the blue-green region to the yellow-red region by selecting the composition and composition ratio, and the color tone and emission Brightness, quantum efficiency, etc. can be adjusted widely.
For example, the color tone, light emission luminance, and quantum efficiency can be adjusted by using two or more Group II elements and changing the ratio.
(2) Although the YAG phosphor hardly emits light when excited by light in the ultraviolet to short wavelength visible region, the oxynitride phosphor of the fourth embodiment excites light in the ultraviolet to short wavelength visible region. High luminous efficiency can be obtained.
That is, the phosphor suitable for combination with the light emitting element in the visible region of ultraviolet to short wavelength can be provided by the oxynitride phosphor of the fourth embodiment.
(3) Since it is crystalline, it can be easily produced as a powder or granule, and its handling and processing are easy.
In the light emitting device of the fourth embodiment, the constituent elements other than the oxynitride phosphor are the same as those of the first embodiment, and thus the description thereof is omitted.

Embodiment 5 FIG.
The light emitting device according to the fifth embodiment of the present invention is the same as the light emitting device according to the first embodiment except that a light emitting element that emits ultraviolet light and a blue phosphor are used instead of the blue light emitting element. It is comprised similarly to the form 1 of.
In the light emitting device of the fifth embodiment configured as described above, the light emitting element that emits ultraviolet light excites the blue phosphor to generate blue light, and the blue light generates the YAG phosphor and the nitride fluorescence. Excites the body.
That is, the light emitting device of the fifth embodiment is different from the first embodiment in that a blue phosphor excited by a light emitting element that emits ultraviolet light is used as an excitation light source. This is the same as in Embodiment 1 in that the color of light emitted from the light emitting device is determined by the color mixture of the color and the color of light emitted from the nitride phosphor.

The blue phosphor as the excitation light source has a feature that its emission wavelength (emission spectrum) hardly changes even if the wavelength of ultraviolet light of the light emitting element changes.
Therefore, in the light emitting device of the fifth embodiment, the color shift due to the fluctuation of the wavelength of the excitation light source hardly occurs, so that an amber light emitting device with little color shift can be realized.
Therefore, in the light emitting device of the fifth embodiment, it is not necessary to consider the wavelength dependency of each phosphor in setting the emission color of the YAG phosphor and the composition and composition ratio of the nitride phosphor. In addition to increasing the degree of freedom in selecting the ratio, an amber light emitting device with little color misregistration can be realized as in the light emitting device of the second embodiment.

Hereinafter, the blue phosphor of the fifth embodiment will be described.
As a blue fluorescent substance of this Embodiment 5, it can select from the following (1)-(13), for example.
_{(1) (M1 1-a} -b Eu a L1 b) 10 fluorescent substance represented by _{(PO 4)} 6 _{Q 2,}
However, M1 is at least one selected from Mg, Ca, Ba, Sr, Zn, L1 is at least one selected from Mn, Fe, Cr, Sn, and Q is a halogen element F, Cl, Br. , At least one selected from I. 0.0001 ≦ a ≦ 0.5 and 0.0001 ≦ b ≦ 0.5.
(2) a fluorescent substance represented by (M1 _1-a Eu _a ) ₁₀ (PO ₄ ) ₆ Q ₂ ;
However, M1 has at least one selected from Mg, Ca, Ba, Sr, and Zn, and Q has at least one selected from halogen elements F, Cl, Br, and I. 0.0001 ≦ a ≦ 0.5.
_{(3) (M1 1-a} -b Eu a Mn b) 10 fluorescent substance represented by _{(PO 4)} 6 _{Q 2,}
However, M1 has at least one selected from Mg, Ca, Ba, Sr, and Zn, and Q has at least one selected from halogen elements F, Cl, Br, and I. 0.0001 ≦ a ≦ 0.5 and 0.0001 ≦ b ≦ 0.5.
_{(4) (M2 1-a} -c Eu a Ba c) 10 fluorescent substance represented by _{(PO 4)} 6 _{Q 2,}
However, M2 has at least one selected from Mg, Ca, Sr, and Zn, and Q has at least one selected from halogen elements F, Cl, Br, and I. 0.0001 ≦ a ≦ 0.5 and 0.10 ≦ c ≦ 0.98.
(5) a fluorescent material represented by M1 _1-a Eu _a Al ₂ O ₄ ;
However, M1 has at least 1 sort (s) selected from Mg, Ca, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5.
(6) a fluorescent material represented by M1 _1-ab Eu _a Mn _b Al ₂ O ₄ ,
However, M1 has at least 1 sort (s) selected from Mg, Ca, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5 and 0.0001 ≦ b ≦ 0.5.
(7) a fluorescent material represented by M3 _1-ac Eu _a Ca _c Al ₂ O ₄ ;
However, M3 has at least 1 sort (s) selected from Mg, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5 and 0.10 ≦ c ≦ 0.98.
(8) A fluorescent material represented by M4 _1-a Eu _a MgAl ₁₀ O ₁₇ ,
However, M4 has at least 1 sort (s) selected from Ca, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5.
(9) A fluorescent material represented by M4 _1-a Eu _a Mg _1-b Mn _b Al ₁₀ O ₁₇ ,
However, M4 has at least 1 sort (s) selected from Ca, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5 and 0.0001 ≦ b ≦ 0.5.
(10) A fluorescent material represented by (M1 _1-a Eu _a ) ₄ Al ₁₄ O ₂₅ ,
However, M1 has at least 1 sort (s) selected from Mg, Ca, Ba, Sr, and Zn. 0.0001 ≦ a ≦ 0.5.
(11) a fluorescent material represented by ZnS: Ag,
(12) A fluorescent material represented by (Zn, Cd) S: Ag, Mn,
(13) (M _1-a Eu _a ) ₂ B ₅ O ₉ Q (M is at least one selected from Mg, Cu, Ba, Sr, Zn, and Q is from F, Cl, Br, I) And at least one selected fluorescent material).
Since other elements such as other nitride phosphors, YAG phosphors, and light emitting elements are the same as those in the first embodiment, detailed description thereof will be omitted.

Embodiment 6 FIG.
The light-emitting device of Embodiment 6 according to the present invention is a surface-mounted light-emitting device that includes a light-emitting element of visible light with ultraviolet or relatively short wavelength and a nitride phosphor, and is capable of emitting amber color ( FIG. 5).
In Embodiment 5, a light-emitting element 101 similar to the light-emitting element 10 of Embodiment 1 can be used.

The package 105 of the light emitting device according to the sixth embodiment is made of Kovar, and includes a central portion in which a concave portion is formed and a bowl-shaped base portion positioned around the central portion. A Kovar lead electrode 102 is inserted and fixed in the base portion in an airtight manner so as to sandwich the concave portion. A Ni / Ag layer is formed on the surfaces of the package 105 and the lead electrode 102.
The LED chip 101 is die-bonded with an Ag—Sn alloy in the recess of the package 105 configured as described above. With this configuration, all the constituent members of the light emitting device can be made of an inorganic material, and the light emitted from the LED chip 101 can be remarkably reliable even if the light emitted from the LED chip 101 is in the ultraviolet region or the short wavelength region of visible light. A light emitting device with high brightness can be obtained.

Next, each electrode of the die-bonded LED chip 101 and each lead electrode 102 are electrically connected by an Ag wire 104, respectively. Then, after sufficiently removing moisture in the concave portion of the package, a Kovar lid 106 having a glass window 107 at the center is put and sealed by seam welding.
The glass window 107 includes, for example, a nitride phosphor such as Ca ₂ Si ₅ N ₈ : Eu, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce added with B, and a YAG phosphor. The color conversion layer 109 containing is formed. The color conversion layer 109 contains a phosphor 108 made of a nitride phosphor in a slurry made of 90 wt% nitrocellulose and 10 wt% γ-alumina in advance, and the back surface of the translucent window 107 (the surface facing the recess). It is formed by being applied to and cured by heating at 220 ° C. for 30 minutes.

  In the surface-mounted light emitting device of the sixth embodiment configured as described above, the combination of the light emitting element and the phosphor is the same blue light emitting element and nitride phosphor as in any of the first to third embodiments. And a combination of a YAG phosphor, an ultraviolet light emitting device similar to that of the fourth embodiment, a combination of a nitride phosphor and an oxynitride phosphor, an excitation light source comprising the same ultraviolet light emitting device and a blue phosphor as those of the fifth embodiment, and Any combination of nitride phosphors and YAG phosphors may be used, and each has the same effect as in the first to fifth embodiments.

In the above embodiment, an example in which a light emitting diode is used as excitation light for a phosphor has been described. However, the present invention is not limited to this, and a laser diode may be used.
Moreover, it cannot be restricted to a semiconductor light emitting element, You may use another excitation light source.
In the above embodiment, a combination of a nitride phosphor and a YAG-based phosphor or an oxynitride phosphor has been described. However, the present invention is not limited to this, for example, a nitride phosphor. And phosphors other than YAG phosphors or oxynitride phosphors can be combined.

  Hereinafter, examples according to the present invention will be described in detail with reference to comparative examples. Needless to say, the present invention is not limited to the following examples.

[Example 1]
In Example 1, a blue light emitting element is used as the light emitting element, a YAG phosphor as the first phosphor of the present invention, and a nitride phosphor as the second phosphor, and the structure shown in FIG. A light emitting device (light emitting diode) was prepared. In addition, as a comparative example, characteristics with an AlInGaP light emitting element were evaluated.
Specifically, in Example 1, a blue light-emitting element having an emission peak wavelength of 460 nm is used as the light-emitting element, and (Y, Gd) ₃ Al ₅ O ₁₂ : Ce is used as the YAG-based phosphor. , Ca ₂ Si ₅ N ₈ : Eu was used.
In Example 1, the ratio of resin to phosphor was resin: YAG phosphor: nitride phosphor = 10: 3.5: 3.5.
As described above, when the amount of the phosphor with respect to the resin is 70%, the light emitting device having the structure of FIG.

FIG. 6 shows the emission spectrum of Example 1 configured as described above together with the emission spectrum of the comparative example. As shown in FIG. 6, both Example 1 and the comparative example can emit amber light, but the half value width of the comparative example is about 15 nm, whereas Example 1 has 120 nm, which is remarkable in the half value width. There is a big difference. This Example 1 is very excellent in visibility since the half width is wide.
The measurement values shown in FIGS. 6 to 11 and 14 are measured under the conditions of DC drive and environmental temperature Ta = 25 ° C. FIG. 6 shows measured values at If = 20 mA.

  FIG. 7 shows the change of the emission spectrum (the spectrum of the light emitting device) when the input current to the light emitting element is changed in the light emitting device of Example 1, and FIG. 8 shows the AlInGaP type of the comparative example. In the light emitting element, the change in the emission spectrum when the input current is changed is shown. 7 and 8, the light-emitting device of Example 1 shows almost no change in the emission peak of the emission spectrum even when the input current to the light-emitting element is changed, whereas the AlInGaP-based light-emitting element of the comparative example When the input current is changed, the peak wavelength of the emission spectrum changes (the emission peak wavelength shifts to the longer wavelength side).

In addition, in FIG. 14, for each of Example 1 and Comparative Example, the change in chromaticity with respect to the change in current input to the light emitting element is shown on the chromaticity diagram.
As shown in FIG. 14, in the light emitting device of Example 1, the chromaticity hardly changes with respect to the fluctuation of the current input to the light emitting element, whereas in the comparative example, the color with respect to the fluctuation of the current input to the light emitting element. The degree is changing.
FIG. 9 shows the fluctuation of the emission spectrum with respect to the change in input current in the light emitting element used in Example 1.

By comparing FIG. 7 and FIG. 9, in the light emitting device of Example 1, when the current input to the light emitting element is changed, the peak wavelength of the emission spectrum of the light emitting element changes (the blue light emitting element increases the current). The emission peak shifts to the short wavelength side), but it can be seen that the peak wavelength of the emission spectrum of the entire light emitting device hardly changes.
That is, the emission peak wavelength due to the color mixture of the first light from the first phosphor excited by the light emitted from the light emitting element emitting blue light and the second light from the second phosphor is input. Even if the current is increased, there is no deviation. This result indicates that the light emitted from the blue light emitting element is hardly emitted to the outside.

  FIG. 10 shows an increase in light output when the input current is increased for each of the example and the comparative example. As shown in FIG. 10, it can be seen that the output of the light emitting device of Example 1 is higher than that of the comparative example with respect to the input current. In the light emitting diode of the comparative example, the light output is saturated at 40 mA, and the light output hardly increases even if the input current is increased further. In contrast, in the light emitting device of Example 1, the light output increases almost linearly until the input current is 60 mA or more.

  FIG. 11 is a graph showing the total luminous flux with respect to the input current for each of Example 1 and the comparative example. Similar to the light output, with respect to the total light output from the light emitting device, the output of Example 1 is higher than that of the comparative example when the input current is increased. In the light emitting diode of the comparative example, the total luminous flux is almost saturated at 40 mA, and the total luminous flux hardly increases even when the input current is further increased. In contrast, in the light emitting device of Example 1, the total luminous flux increases almost linearly until the input current is 60 mA or more.

Further, the total luminous flux with respect to the ambient temperature of the light emitting device of Example 1 was evaluated. The results are shown in FIG. 12 together with commercially available AlInGaP-based light-emitting elements (manufactured by A company, manufactured by B company, and manufactured by C company).
The measured values shown in FIG. 12 are measured under conditions of pulse driving, Ifp = 20 mA, frequency 200 Hz, pulse width = 50 μsec, and duty ratio 1%.
As shown in FIG. 12, the light emitting device of Example 1 has a smaller temperature dependency of the light emission output (total luminous flux) than the commercially available AlInGaP light emitting elements (manufactured by A, B, and C). It can be seen that a stable light output can be obtained.

[Examples 2 to 4]
In Examples 2 to 4, the same blue light-emitting element and phosphor as in Example 1 were used, and the ratio of the phosphor to the resin in the coating part was changed to produce and evaluate the light-emitting device shown in FIG.
In addition, the density | concentration of fluorescent substance was computed by the total amount of the 1st fluorescent substance and the 2nd fluorescent substance with respect to resin.
The ratio of the phosphor to the resin is 15% in Example 2, 20% in Example 3, and 25% in Example 4. In addition, the ratio here is a weight ratio.
Here, three samples were prepared for each example in consideration of manufacturing variations.

Table 1 shows the chromaticity (x, y) of each sample.
[Table 1]

Further, on the chromaticity diagram, as shown in FIG. 15, the second embodiment is on the boundary of the amber standard (C), the third embodiment is in the standards (A) and (C), and Example 4 was included in all of the standards (A) to (C). From this, it can be seen that by setting the concentration of the phosphor in the coating portion to 15% or more with respect to the resin, it is possible to obtain amber light emitting devices that can be used for various applications.
The measured values shown in FIG. 15 are measured under conditions of pulse driving, Ifp = 350 mA, environmental temperature Ta = 25 ° C., frequency 200 Hz, pulse width = 50 μsec, and duty ratio 1%.

Moreover, the emission spectrum of Examples 2-4 is shown in FIG. As shown in FIG. 16, the emission colors of the light emitting devices of Examples 2 to 4 are all amber, whereas in the light emitting devices of Examples 3 and 4, no peak due to light emission of the blue light emitting element is observed. In the light-emitting device of Example 2, a peak due to light emission of the blue light-emitting element (approximately 10% intensity with respect to the main peak of the light-emitting device) is observed at a wavelength of 460 nm. That is, in the present invention, an amber light emitting device can be realized by suppressing at least leakage of light from the light emitting element to 10% or less with respect to the main peak of the light emitting device.
In the light emitting devices of Examples 3 and 4, the light leakage of the light emitting elements to the outside is 0.03 and 0.01 with respect to the main peak of the light emitting device, respectively, and this ratio is 0.01 or less. Thus, the amber color standard (B) can be satisfied.

In the present invention, since the emission color of the light emitting device is substantially determined by the emission color of the phosphor, the main peak intensity of the light emitting device is substantially equal to the emission intensity of the phosphor. Therefore, suppressing the light leakage of the light emitting element to 10% or less with respect to the main peak of the light emitting device means that the light leakage intensity of the light emitting element is suppressed to 10% or less with respect to the main peak of the light emission intensity of the phosphor. Means that.
In Example 2, the peak wavelength was 605 nm, the half width was 108.4 nm, the output Po was 36.4 mW, and the total luminous flux was 11.5 lm (lumen).
In Example 3, the peak wavelength was 606 nm, the half width was 105.9 nm, the output Po was 31.3 mW, and the total luminous flux was 9.4 lm (lumen).
Further, in Example 4, the peak wavelength was 607 nm, the half width was 102.5 nm, the output Po was 26.8 mW, and the total luminous flux was 7.7 lm (lumen).

[Example 5]
In Example 5, a blue light-emitting element having an emission peak wavelength of 460 nm is used as the light-emitting element, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce is used as the YAG phosphor, and Ca ₂ is used as the nitride-based phosphor. Si ₅ N ₈ : Eu was used. The ratio of the phosphor to the resin was 25%.
As a result, the chromaticity point deviated from the amber color standard (B) but entered the standards (A) and (C), and no color shift due to an increase in input current was observed.

[Example 6]
In Example 6, a blue light-emitting element having an emission peak wavelength of 460 nm is used as the light-emitting element, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce is used as the YAG phosphor, and Sr ₂ is used as the nitride-based phosphor. Si ₅ N ₈ : Eu was used. The ratio of the phosphor to the resin was 25%.
As a result, the chromaticity point entered the amber color standard (B), and no color shift due to an increase in input current was observed.

[Example 7]
In Example 7, a blue light emitting element having an emission peak wavelength of 465 nm is used as the light emitting element, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce is used as the YAG phosphor, and Ca ₂ is used as the nitride phosphor. Si ₅ N ₈ : Eu was used. The ratio of the phosphor to the resin was 25%. As a result, the chromaticity point entered the amber color standard (B), and no color shift due to an increase in input current was observed.

It is sectional drawing which shows the structure of the light-emitting device of Embodiment 1 which concerns on this invention. It is a figure which shows the emission spectrum of the light emitting diode which can be used for this invention, and has shown the transition of the spectrum with respect to input current. It is a graph which shows the excitation spectrum of a YAG type fluorescent substance. It is a graph which shows the excitation spectrum of nitride fluorescent substance. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 6 which concerns on this invention. It is a graph which shows the emission spectrum of the light-emitting device of Example 1 which concerns on this invention. In the light-emitting device of Example 1, it is a graph which shows the change of the emission spectrum when an input current value is changed. It is a graph which shows the change of the emission spectrum when the input current value is changed in the light emitting device of the comparative example. 4 is a graph showing changes in the emission spectrum when the input current value is changed in the light-emitting element used in the light-emitting device of Example 1. 6 is a graph showing light emission intensity with respect to input current value in the light emitting device of Example 1. 4 is a graph showing the total luminous flux with respect to the input current value in the light emitting device of Example 1. 4 is a graph showing the temperature dependence of the total luminous flux in the light emitting device of Example 1. It is a chromaticity diagram showing the approximate range of amber color. FIG. 3 is a chromaticity diagram illustrating a light emission color of the light-emitting device of Example 1. It is a chromaticity diagram which shows the luminescent color of the light-emitting device of Examples 2-4 which concerns on this invention. It is a figure which shows the emission spectrum of the light-emitting device of Examples 2-4 which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Semiconductor layer 3 Electrode 4 Bump 10 Light emitting element 11 Phosphor 12 Coating member 13 Lead frame 13a Mount lead 13b Inner lead 14 Conductive wire 15 Mold member 101 Light emitting element 102 Lead electrode 103 Insulating sealing material 104 Conductive wire 105 Package 106 Lid 107 Window 108 Phosphor 109 Coating member

Claims (17)

A light emitting element that emits ultraviolet to blue light, a first phosphor that is excited by light emitted from the light emitting element and emits first light in a longer wavelength region than the excitation light, and the light emitting element emits light. A second phosphor made of a nitride phosphor that is excited by light and emits second light in a longer wavelength region than the first light, and includes the first light and the second light. A light emitting device having an emission color by color mixing. The nitride phosphor has the general formula, L _X M _Y N _{((2/3) X + (4/3) Y)} : R or L _X M _Y O _Z N _{((2/3) X + (4/3) ) Y- (2/3) Z)} : R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is C, At least one group IV element selected from the group consisting of Si, Ge, Sn, Ti, Zr, and Hf, where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, And at least one rare earth element selected from the group consisting of Dy, Ho, Er, and Lu. X, Y, and Z are 0.5 ≦ X ≦ 3, 1.5 ≦ Y ≦ 8, and 0 <Z ≦. The light-emitting device according to claim 1, wherein the light-emitting device is a nitride phosphor represented by 3). The light emitting device according to claim 1, wherein the light emitting element is a blue light emitting element, and the first phosphor is a YAG phosphor. The light-emitting device according to claim 1, wherein the light-emitting element is an ultraviolet light-emitting element, and the first phosphor is an oxynitride phosphor. The oxynitride phosphor has a general formula L _X M _Y O _Z N _{((2/3) X + (4/3) Y- (2/3) Z)} : R or L _X M _Y Q _T O _Z N _{((2/3) X + (4/3) Y + T− (2/3) Z)} : R (where L is at least selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn) It is a Group II element that is one or more, and M is a Group IV element that is at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf. It is at least one group III element selected from the group consisting of B, Al, Ga, and In, O is an oxygen element, N is a nitrogen element, and R is a rare earth element. 0.5 <X <1.5, 1.5 <Y <2.5, 0 <T <0.5, 1.5 <Z <2.5.) The light emitting device according to claim 4, wherein the object phosphor. The light-emitting device according to claim 1, wherein the nitride phosphor is a nitride phosphor containing Ca and Si. The emission peak wavelength of the light emitting element is longer than the peak wavelength of the first excitation spectrum of the first phosphor and the peak wavelength of the second excitation spectrum of the second phosphor, and the light emission The light-emitting device according to claim 1, wherein each of the first excitation spectrum and the excitation spectrum has a negative slope in a fluctuation range of an emission peak wavelength of the element. The rate of change of the excitation efficiency of the first phosphor and the second phosphor represented by the first excitation spectrum and the inclination of the excitation spectrum with respect to the excitation wavelength is substantially within the fluctuation range of the emission peak wavelength of the light emitting element. The light emitting device according to claim 7, which is equal to each other. The light-emitting device according to claim 1, wherein the nitride phosphor includes B at a ratio of 1 ppm to 10000 ppm. The light emitting device according to claim 1, wherein a crystal structure of the nitride phosphor is monoclinic or orthorhombic. The light emitting device according to any one of claims 1 to 10, wherein the intensity of light leaking directly to the outside of the light emission of the light emitting element is 10% or less of the intensity at the main peak of light emission of the phosphor. A light emitting element that emits ultraviolet light; a blue phosphor that emits blue light when excited by light emitted from the light emitting element; and first light that is excited by the blue light and has a longer wavelength range than the blue light. A first phosphor that emits light, and a second phosphor made of a nitride phosphor that is excited by the blue light and emits second light in a longer wavelength region than the first light, and A light emitting device having a light emission color by a color mixture of the first light and the second light. The nitride phosphor has the general formula, L _X M _Y N _{((2/3) X + (4/3) Y)} : R or L _X M _Y O _Z N _{((2/3) X + (4/3) ) Y- (2/3) Z)} : R (L is at least one group II element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is C, At least one group IV element selected from the group consisting of Si, Ge, Sn, Ti, Zr, and Hf, where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, And at least one rare earth element selected from the group consisting of Dy, Ho, Er, and Lu, where X, Y, and Z are 0.5 ≦ X ≦ 3, 1.5 ≦ Y ≦ 8, and 0 <Z ≦. 13. The light-emitting device according to claim 12, wherein the light-emitting device is a nitride phosphor represented by (3). The light emitting device according to claim 12 or 13, wherein the first phosphor is a YAG phosphor. The light-emitting device according to claim 12, wherein the nitride phosphor is a nitride phosphor containing Ca and Si. The light-emitting device according to any one of claims 12 to 15, wherein the nitride phosphor contains B at a ratio of 1 ppm to 10000 ppm. The light emitting device according to any one of claims 12 to 16, wherein a crystal structure of the nitride phosphor is monoclinic or orthorhombic.

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