Phosphor, light emitting device, lighting device, image display device, and indicator lamp for vehicles

Abstract

The present invention addresses the problem of providing: a phosphor which has good emission peak wavelength and / or good absorption efficiency of excitation light; and a light emitting device which has good color rendering properties or color reproducibility, and good conversion efficiency. The present invention relates to a phosphor which includes a crystal phase that has a composition represented by formula (1) or (2). (1): MAa-x-y-zRexMYyMZzMBbMC3-wMWwDd (2): MAa-x-yRexMYyMBb+v1MC3-v2Dd (In the formulae, the definition of each symbol is as set forth in the description.)

Description

Phosphor, light-emitting device, lighting device, image display device, and vehicle indicator light

[0001] The present invention relates to a phosphor, a light-emitting device, a lighting device, an image display device, and a vehicle indicator light.

[0002] In recent years, the trend toward energy conservation has led to an increasing demand for LED-based illumination and backlights. The LEDs used here are white-emitting LEDs that have a phosphor disposed on an LED chip that emits light in the blue or near-ultraviolet wavelengths.

[0003] In recent years, white light-emitting LEDs of this type have been developed that use a nitride phosphor that emits red light and a phosphor that emits green light on a blue LED chip, using blue light from the blue LED chip as excitation light. LEDs are required to have higher luminous efficiency, and there is a demand for phosphors with excellent luminous properties as red phosphors, as well as light-emitting devices that include such phosphors.

[0004] The red phosphor used in the light emitting device is, for example, a compound represented by the general formula K ２ (Si,Ti)F ６ : Mn, K ２ Si １－ｘ Na ｘ Al ｘ F ６ : KSF phosphor represented by Mn (0<x<1), general formula (Sr, Ca)AlSiN ３ However, KSF phosphors are activated with Mn and are therefore toxic, and therefore phosphors that are more environmentally friendly and friendly to humans are being sought. Furthermore, many S / CASN phosphors have a relatively wide half-width in their emission spectra (hereinafter sometimes referred to as "spectral half-width", "A full width at half maximum", or "FWHM") of about 80 nm to 90 nm, and therefore the emission wavelength range tends to include a wavelength range with low luminous efficiency. Therefore, from the viewpoint of improving conversion efficiency, red phosphors with narrower spectral half-widths are being sought.

[0005] Furthermore, as a red phosphor that can be applied to recent light-emitting devices, for example, Patent Document 1 discloses in the examples thereof SrLiAl ３ N４ :Eu, and Non-Patent Document 1 discloses SrLi(Al,Ga) ３ N ４ :Eu are disclosed.

[0006] Japanese Patent No. 6335884

[0007] CHEMISTRY OF MATERIALS, Vol. 31, pp. 4614-4618

[0008] However, Patent Document 1 only provides phosphors with an emission peak wavelength of 650 nm or more, and because the emission intensity is high at wavelengths above 650 nm, where the relative luminous efficiency is low, the emission intensity is high at wavelengths above 650 nm, where the relative luminous efficiency is low, causing a decrease in the conversion efficiency of the light-emitting device. Furthermore, Non-Patent Document 1 successfully achieves a blue shift in the emission peak wavelength compared to the composition of Patent Document 1, but samples with an emission peak wavelength of 648 nm or less have low quantum efficiency, which also causes a decrease in the conversion efficiency of the light-emitting device. Thus, in order to obtain a light-emitting device with excellent conversion efficiency, a red phosphor is needed that has an appropriate emission peak wavelength and can efficiently convert excitation light into emitted light.

[0009] In view of the above problems, the present invention aims to provide a phosphor having a good emission peak wavelength and / or good excitation light absorption efficiency, and a light-emitting device having good color rendering or color reproducibility and good conversion efficiency.

[0010] After extensive research, the inventors discovered that the above-mentioned problems can be solved by using a phosphor containing a crystalline phase represented by a specific composition, and thus completed the present invention. Several non-limiting embodiments are presented below. The present invention also includes embodiments that further include some or all of the features of one or more of the other embodiments in addition to any of the embodiments presented below.

[0011] A first aspect of the present invention relates to a phosphor comprising a crystalline phase having a composition represented by the following formula [1]: MA ａ－ｘ－ｙ－ｚ Re ｘ M.Y. ｙ MZ ｚ MB ｂ MC ３－ｗ MWｗ D ｄ [1] (In the above formula [1], MA includes one or more elements selected from the group consisting of Sr, Ca, and Ba, MB includes Li, MC includes one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc, D includes one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes N (nitrogen), Re includes one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb, MY includes one or more elements selected from the group consisting of Y, La, and Lu, MZ includes one or more elements selected from the group consisting of Na, K, and Rb, MW includes one or more elements selected from the group consisting of Mg and Zn, a, b, d, x, y, z, and w each independently satisfy the following formulae: 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦z≦0.5 0.0<x+y+z<a 0.0≦w≦0.5

[0012] A second aspect of the present invention relates to a phosphor comprising a crystalline phase having a composition represented by the following formula [2]: MA ａ－ｘ－ｙ Re ｘ M.Y. ｙ MB ｂ＋ｖ１ MC ３－ｖ２ D ｄ[2] (In the above formula [2], MA contains one or more elements selected from the group consisting of Sr, Ca, and Ba; MB contains Li; MC contains one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc; D contains one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and containing N (nitrogen); Re contains one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MY contains one or more elements selected from the group consisting of Y, La, and Lu; and a, b, d, x, y, v1, and v2 each independently satisfy the following formula: 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦v1≦y 0.0≦v2≦y 0.5y≦v1+v2≦1.5y)

[0013] A third aspect of the present invention relates to the phosphor of the first or second aspect, wherein MC contains at least Al and Ga.

[0014] A fourth aspect of the present invention is a phosphor according to any one of the first to third aspects, wherein the crystal structure of the crystal phase having the composition represented by the formula [1] or [2] is SrLiAl ３ N ４ The same applies to the phosphor.

[0015] A fifth aspect of the present invention relates to the phosphor of any one of the first to fourth aspects, which has an emission peak wavelength in the range of 620 nm or more and 660 nm or less in its emission spectrum.

[0016] A sixth aspect of the present invention relates to a light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body includes the phosphor of any one of aspects 1 to 5.

[0017] A seventh aspect of the present invention relates to the light emitting device of the sixth aspect, wherein the second light emitting body further includes a yellow phosphor and / or a green phosphor.

[0018] An eighth aspect of the present invention relates to the light-emitting device of the seventh aspect, wherein the yellow phosphor and / or the green phosphor includes at least one phosphor selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

[0019] A ninth aspect of the present invention relates to a lighting device including the light-emitting device according to any one of the sixth to eighth aspects as a light source.

[0020] A tenth aspect of the present invention relates to an image display device including the light-emitting device according to any one of the sixth to eighth aspects as a light source.

[0021] An eleventh aspect of the present invention relates to a vehicle indicator lamp including the light-emitting device according to any one of the sixth to eighth aspects as a light source.

[0022] In multiple embodiments, the present invention can provide a phosphor having a good emission peak wavelength and / or good excitation light absorption efficiency, and a light-emitting device having good color rendering or color reproducibility and good conversion efficiency.

[0023] Fig. 1A shows the emission spectra of the phosphors according to Comparative Example 1 and Examples 1 to 4, normalized with the maximum emission intensity set to 1.0. Fig. 1B is an enlarged view of Fig. 1A. Fig. 2 shows the unit cell volumes and measurement errors of the phosphors according to Comparative Example 1 and Examples 1 to 4.

[0024] The present invention will be described below with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and can be modified and implemented as desired within the scope of the gist of the present invention.

[0025] In this specification, a numerical range expressed using "to" means a range including the numerical values ​​written before and after "to" as the lower and upper limits. In addition, in the composition formula of the phosphor in this specification, each composition formula is separated by a comma (,). In addition, when multiple elements are listed separated by a comma (,), it means that one or more of the listed elements may be contained in any combination and composition. For example, "(Ca, Sr, Ba)Al ２ O ４The composition formula "CaAl:Eu" ２ O ４ :Eu" and "SrAl ２ O ４ :Eu” and “BaAl ２ O ４ :Eu" and "Ca １－ｘ Sr ｘ Al ２ O ４ :Eu" and "Sr １－ｘ Ba ｘ Al ２ O ４ :Eu" and "Ca １－ｘ Ba ｘ Al ２ O ４ :Eu" and "Ca １－ｘ－ｙ Sr ｘ Ba ｙ Al ２ O ４ :Eu" (wherein, 0<x<1, 0<y<1, 0<x+y<1).

[0026] <Phosphor> In one embodiment, the present invention provides a phosphor (hereinafter, sometimes referred to as "phosphor according to embodiment 1") that includes a crystalline phase having a composition represented by the following formula [1]: MA ａ－ｘ－ｙ－ｚ Re ｘ M.Y. ｙ MZ ｚ MB ｂ MC ３－ｗ MW ｗ D ｄ[1] (In the above formula [1], MA includes one or more elements selected from the group consisting of Sr, Ca, and Ba, MB includes Li, MC includes one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc, D includes one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes N (nitrogen), Re includes one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb, MY includes one or more elements selected from the group consisting of Y, La, and Lu, MZ includes one or more elements selected from the group consisting of Na, K, and Rb, MW includes one or more elements selected from the group consisting of Mg and Zn, a, b, d, x, y, z, and w each independently satisfy the following formulae: 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦z≦0.5 0.0<x+y+z<a 0.0≦w≦0.5

[0027] In one embodiment, the present invention provides a phosphor (hereinafter, sometimes referred to as "phosphor according to embodiment 2") that includes a crystalline phase having a composition represented by the following formula [2]: MA ａ－ｘ－ｙ Re ｘ M.Y. ｙ MB ｂ＋ｖ１ MC ３－ｖ２ D ｄ[2] (In the above formula [2], MA contains one or more elements selected from the group consisting of Sr, Ca, and Ba; MB contains Li; MC contains one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc; D contains one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and containing N (nitrogen); Re contains one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MY contains one or more elements selected from the group consisting of Y, La, and Lu; and a, b, d, x, y, v1, and v2 each independently satisfy the following formula: 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦v1≦y 0.0≦v2≦y 0.5y≦v1+v2≦1.5y)

[0028] In formula [1] or [2], europium (Eu), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), or the like can be used as Re. From the viewpoint of improving the emission wavelength and the emission quantum efficiency, Re preferably contains one or more elements selected from the group consisting of Eu, Ce, Pr, Tb, and Dy.

[0029] In an embodiment in which Re includes Eu, the proportion of europium (Eu) relative to the total Re activation elements is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more. By including an appropriate amount of Re element in the phosphor, a phosphor exhibiting good luminescence intensity can be obtained.

[0030] In formula [1] or [2], MA usually contains one or more elements selected from the group consisting of calcium (Ca), strontium (Sr), and barium (Ba), and preferably contains Sr.

[0031] In one embodiment, the elements contained in MA account for 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the total MA, and in a specific embodiment, MA consists of the elements described above. Also, in one embodiment, the elements described above are divalent.

[0032] In formula [1] or [2], MB contains at least lithium (Li). In one embodiment, Li accounts for 70 mol % or more of MB, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more. It is particularly preferable that MB consists of Li. Furthermore, Li in MB is usually monovalent. MB may be optionally partially substituted with another element, but the substituted element is preferably monovalent.

[0033] In formula [1] or [2], MC contains one or more elements selected from the group consisting of B (boron), aluminum (Al), silicon (Si), gallium (Ga), indium (In), and scandium (Sc), preferably contains Al, Ga, or Sc, and more preferably contains one or more elements selected from the group consisting of Al and Ga.

[0034] In one embodiment, the elements contained in the MC described above account for 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the entire MC, and in a specific embodiment, the MC consists of the elements described above. Also, in one embodiment, the elements contained in the MC are trivalent.

[0035] In a specific embodiment, 80 mol % or more of MC is Al, preferably 90 mol % or more, more preferably 95 mol % or more, and even more preferably 98 mol % or more. When 80 mol % or more of MC is Al, a red phosphor can be provided that exhibits an emission peak wavelength comparable to that of existing red phosphors such as S / CASN and has a narrow spectral half-width. By including such a red phosphor, a light emitting device can be provided that has good color rendering properties or color reproducibility while maintaining conversion efficiency (Lm / W) comparable to or higher than conventional ones.

[0036] In another particular embodiment, M C comprises Al and one or more elements selected from the group consisting of Si, Ga, In, and Sc (hereinafter, “M C ２ In this embodiment, "MC" in formula [1] and formula [2] ３ "is" (Al １－ｃ MC ２ ｃ ) ３ " can be read as

[0037] In certain embodiments, MC ２ Preferably, c contains Ga, and more preferably consists of Ga. Also, the above c is usually greater than 0.00 and not greater than 0.70.

[0038] From one perspective, the smaller the value of c, the longer the emission peak wavelength and the brighter the red light emitted. A light-emitting device including such a phosphor has a good red color rendering index R9 value. From this perspective, c is preferably 0.67 or less, more preferably 0.60 or less, even more preferably 0.50 or less, and particularly preferably 0.40 or less, with more preferred values ​​being 0.30 or less, 0.20 or less, 0.10 or less, 0.05 or less, and 0.03 or less.

[0039] From another perspective, the larger the value of c, the shorter the emission peak wavelength and the more wavelength components with high relative luminous efficiency are emitted, and therefore a light emitting device including such a phosphor has good conversion efficiency. From this perspective, the values ​​of c in the preferred to most preferred embodiments are, in order, 0.03 or more, 0.05 or more, 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, and 0.65 or more.

[0040] It is preferable that MC contains at least Al and Ga, since the emission peak wavelength can be adjusted and a phosphor having a desired emission peak wavelength can be obtained. In particular, when Re contains Eu and the phosphor is a phosphor that emits red light, the emission peak wavelength can be shortened by including Ga or the like in MC, and a phosphor that emits more light in a region with high relative luminosity can be obtained, which is preferable because it can provide a light-emitting device with good color rendering and improved conversion efficiency. Furthermore, the effect of changing the emission peak wavelength can be further enhanced by combining it with the use of the MY elements described below.

[0041] In the formula [1] or [2], D is selected from nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and I (iodine), and contains one or more elements including at least N (nitrogen).

[0042] In an embodiment in which D contains nitrogen (N) or oxygen (O), the total proportion of nitrogen (N) and oxygen (O) relative to all of D is usually 70 mol % or more, preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more.

[0043] Nitrogen (N) or oxygen (O) may partially contain other elements, such as fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). In the present invention, "containing an element" refers to both a form in which the element is substituted and a form in which the element is included without being substituted.

[0044] In formula [1] or [2], MY contains one or more elements selected from the group consisting of Y, La, and Lu, preferably contains La or Lu, and more preferably contains La. Preferably, 80 mol % or more of MY consists of the above-mentioned elements, more preferably MY consists of the above-mentioned elements. In one embodiment, MY is trivalent.

[0045] When the crystalline phase contains the MY element, a phosphor having an appropriate emission peak wavelength or good absorption efficiency of excitation light can be obtained, and by using such a phosphor, a light-emitting device having good conversion efficiency can be provided.

[0046] In formula [1], MZ contains one or more elements selected from the group consisting of Na, K, and Rb, and preferably contains Na or K. Preferably, 80 mol % or more of MZ is composed of the above elements, and more preferably, MZ is composed of the above elements. In one embodiment, the above elements contained in MZ are monovalent.

[0047] In formula [1], MW contains one or more elements selected from the group consisting of Mg and Zn, preferably Mg. Preferably, 80 mol % or more of MW is composed of the above elements, more preferably, MW is composed of the above elements. In one embodiment, the above elements contained in MW are divalent.

[0048] When the crystalline phase having the composition represented by formula [1] contained in the phosphor according to the first embodiment contains an appropriate amount of MZ or MW, the overall charge balance is stabilized.

[0049] In addition to the intended elements, impurity elements having similar properties may be unintentionally or unavoidably mixed into the MA, MB, MC, D, Re, MY, MZ and MW. However, these are not excluded from the present invention as long as they do not impair the essence or effect of the present invention or eliminate the effect of the present invention.

[0050] Here, the impurity element may be an element not intended to be included in each site among the elements listed as elements that may be included in the MA, MB, MC, D, Re, MY, MZ, and MW sites, or an element other than the listed elements. For example, when a phosphor is manufactured with the intention that MA be composed of Ca and / or Sr, elements other than the aforementioned Ca and Sr may be inevitably mixed into the raw materials, or trace amounts may be mixed in when a flux (flux) is used in the manufacture of the phosphor, resulting in partial substitution of MA with Ba, Mg, or other elements. However, this invention does not exclude these, as long as they do not impair the essence of the invention or the effects of the invention. The same applies when the above MA is replaced with MB, MC, D, or Re, the above Ca or Sr is replaced with one or more of the elements listed as elements that may be included in each site, and the above Ba and Mg are replaced with other elements.

[0051] O (oxygen) may be intentionally included in the phosphor for the purpose of maintaining the charge balance of the entire phosphor or for adjusting the emission peak wavelength, but even when the phosphor is produced with the intention of not containing oxygen, it may be mixed in as an impurity in the raw material metal or introduced during the production process, such as the crushing step or nitriding step, and therefore, in the phosphor of the present invention, oxygen will inevitably be mixed in even if it is not intended to be.

[0052] The allowable oxygen content when formula [1] is produced with the intention of not containing oxygen is usually 10% by mass or less, preferably 6% by mass or less, more preferably 4% by mass or less, and even more preferably 2% by mass or less, within the range in which a decrease in the luminescence properties of the phosphor is acceptable.

[0053] In another embodiment, the amount of O (oxygen) contained in the formula [1] or [2] is 1.0 mol or less, preferably 0.8 mol or less, more preferably 0.6 mol or less, even more preferably 0.4 mol or less, and particularly preferably 0.2 mol or less, when the total of MC and MW is 3.0 mol, and the lower limit is not particularly limited.

[0054] Like oxygen, halogen atoms may be contained in the phosphor of the present invention. Halogen atoms may be contained in the phosphor when they are mixed in as impurities in the raw material metals, or when they are introduced during the manufacturing process such as the pulverization step or nitriding step. In particular, when a halide is used as a flux, halogen atoms may be contained in the phosphor.

[0055] As described above, examples of the halogen element to be mixed include fluorine, chlorine, bromine, and iodine. The halogen element content is preferably 1% by mass or less, more preferably 0.5% by mass or less, so that the light-emitting properties of the phosphor are acceptable.

[0056] In the formula [1], a represents the total molar content of MA, Re, MY, and MZ, and b, d, x, y, z, and w represent the molar contents of MB, D, Re, MY, MZ, and MW, respectively. In the formula [2], a represents the total molar content of MA, Re, and MY, and b+v1, d, x, y, and 3-v2 represent the molar contents of MB, D, Re, MY, and MC, respectively.

[0057] The ideal ratio for a stable crystal structure is when a, b, and d are 1, 1, and 4, respectively. However, in reality, the values ​​of a, b, and d may vary slightly from the ideal ratio due to various factors such as single atom vacancies, changes in composition due to oxidation of the phosphor surface, heterogeneous phases, and charge compensation. However, these variations are not excluded from the present invention as long as they do not impair the essence or effect of the present invention. Specifically, the ranges of values ​​that can be tolerated for a, b, d, x, y, z, w, v1, and v2 are listed below.

[0058] In the formula [1] or [2], the value of a is 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, and is 1.3 or less, preferably 1.2 or less, more preferably 1.1 or less.

[0059] In the formula [1] or [2], the value of b is 0.7 or more, preferably 0.8 or more, more preferably 0.9 or more, and is 1.3 or less, preferably 1.2 or less, more preferably 1.1 or less.

[0060] In the formula [1] or [2], the value of d is 3.2 or more, preferably 3.4 or more, more preferably 3.6 or more, and even more preferably 3.8 or more, and is 4.8 or less, preferably 4.6 or less, more preferably 4.4 or less, and even more preferably 4.2 or less.

[0061] When the value of a is within the above range, the crystal structure is stabilized and a phosphor with few heterophases is obtained. By including such a red phosphor, it is possible to provide a light-emitting device that has good absorption efficiency of excitation light and good red and overall conversion efficiency.

[0062] Furthermore, when b and d are within the above ranges, the crystal structure is stabilized. Furthermore, the value of d can be adjusted appropriately in order to maintain the charge balance of the entire phosphor.

[0063] In the formula [1] or [2], the value of x is greater than 0.0, preferably 0.0001 or more, more preferably 0.001 or more, and is 0.2 or less, preferably 0.15 or less, more preferably 0.12 or less, even more preferably 0.1 or less, and still more preferably 0.08 or less.

[0064] When the value of x is equal to or greater than the above-mentioned lower limit or greater than 0, or equal to or greater than the above-mentioned preferable lower limit, a phosphor with good luminescence intensity can be obtained, and when the value of x is equal to or less than the above-mentioned upper limit, Re can be well incorporated into the crystal, and a phosphor that easily functions as a luminescence center can be obtained. By including such a red phosphor, a light-emitting device with good conversion efficiency can be provided.

[0065] In the formula [1] or [2], the value of y is greater than 0.0, preferably 0.0005 or more, more preferably 0.001 or more, even more preferably 0.005 or more, and is 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less, even more preferably 0.2 or less, particularly preferably 0.1 or less, extremely preferably 0.05 or less, and most preferably 0.02 or less.

[0066] When the value of y is equal to or greater than the lower limit, a phosphor having a shorter emission peak wavelength or a phosphor having good absorption efficiency of excitation light can be obtained, and by including such a phosphor, a light-emitting device having good conversion efficiency can be provided. When the value of y is equal to or less than the upper limit, a phosphor having good emission intensity can be obtained, and by including such a phosphor, a light-emitting device having good conversion efficiency can be provided.

[0067] In the formula [1], the values ​​of z and w are each independently 0.0 or more and 0.5 or less. In one embodiment, the sum of z and w is 0.5 times or more of y, preferably 0.7 times or more of y, more preferably 0.8 times or more of y, and even more preferably 0.9 times or more of y, and is usually 1.5 times or less of y, preferably 1.3 times or less of y, more preferably 1.2 times or less of y, and even more preferably 1.1 times or less of y.

[0068] When the values ​​of z and w satisfy the above ranges, charge balance can be maintained throughout the crystalline phase having the composition represented by formula [1]. When both values ​​are within the above ranges, it is preferable in that the red phosphor obtained has a good emission peak wavelength and a good half-value width in the emission spectrum.

[0069] In the formula [1], the sum of x, y, and z is greater than 0.0 and less than a. In this embodiment, Re, MY, and MZ are elements that substitute for the MA site as a solid solution, and a means the sum of the elements contained in the MA site, i.e., MA, Re, MY, and MZ, which means that the sum of x, y, and z does not exceed the total value a of the MA site.

[0070] In the formula [2], v1 and v2 are each independently 0 or more and y or less. The sum of v1 and v2 is 0.5y or more, preferably 0.6y or more, more preferably 0.7y or more, even more preferably 0.8y or more, particularly preferably 0.9y or more, and 1.5y or less, preferably 1.4y or less, more preferably 1.3y or less, even more preferably 1.2y or less, particularly preferably 1.1y or less. When MY substitutes for the MA site, the molar contents of the MB and MC sites decrease, thereby maintaining an overall charge balance and making the phosphor chemically and electrically stable.

[0071] The method for identifying the elemental composition of the red phosphor is not particularly limited, and can be determined by a conventional method, such as GD-MS, ICP spectroscopy, or energy dispersive X-ray analysis (EDX).

[0072] The phosphors according to the first and second embodiments share the same problems and effects in the technical concept of attempting to solve the above-mentioned problems by substituting part of the MA element with MY to obtain a phosphor with a good emission wavelength, while maintaining the overall charge balance by substituting other elements or adjusting the element ratio.

[0073] [Particle size of phosphor] The particle size of a phosphor containing a crystalline phase having a composition represented by formula [1] or [2] is typically 2 μm or more and 40 μm or less in volume median particle size (volume median particle size), with the lower limit being preferably 3 μm, more preferably 4 μm, and even more preferably 5 μm, and the upper limit being preferably 35 μm, more preferably 30 μm, even more preferably 25 μm, and particularly preferably 20 μm.

[0074] A volume-based median particle size (volume median particle size) of not less than the above lower limit is preferable from the viewpoint of improving the light-emitting characteristics exhibited by the crystalline phase within the LED package, and a volume-based median particle size of not more than the above upper limit is preferable from the viewpoint of preventing nozzle clogging during the manufacturing process of the LED package.

[0075] The volume-based median particle size (volume median particle size) of the crystalline phase of the phosphor can be measured by a measurement technique known to those skilled in the art, but in a preferred embodiment, it can be measured by, for example, a laser granulometer. In the examples herein, the volume-based median particle size (volume median particle size, (d ５０ ) is defined as the particle size at which the volume-based relative particle amount becomes 50% when a sample is measured using a particle size distribution analyzer that uses the laser diffraction / scattering method as its measurement principle and the particle size distribution (cumulative distribution) is calculated.

[0076] {Physical Properties of Red Phosphors, etc.} [Space Group] The crystal system (space group) of the crystalline phase having the composition represented by the formula [1] or [2] is not limited as long as the effects of the invention can be obtained. In one embodiment, the crystal system (space group) of the crystalline phase having the composition represented by the formula [1] or [2] is SrLiAl ３ N ４ In one embodiment, tetragonal P4 ２ / m, monoclinic P-1, etc., and preferably P-1. The space group in the phosphor of this embodiment is not particularly limited as long as the average structure considered statistically within a range distinguishable by powder X-ray diffraction or single crystal X-ray diffraction exhibits a repeating period of the above length, but it is preferable that it belongs to number 2 based on "International Tables for Crystallography (Third, revised edition), Volume A SPACE-GROUP SYMMETRY". For example, in a phosphor according to one embodiment, the crystal structure of the crystalline phase having the composition represented by the formula [1] or [2] is SrLiAl ３ N ４ The above space group narrows the full width at half maximum (FWHM) of the emission spectrum, and a phosphor with high luminous efficiency can be obtained.

[0077] Here, the space group can be determined by a conventional method, for example, by electron diffraction, X-ray diffraction structure analysis using powder or single crystal, or neutron diffraction structure analysis.

[0078] In a specific embodiment of the phosphor according to embodiment 1 or 2, when the intensity of the peak appearing in the region of 2θ=38 to 39 degrees in a powder X-ray diffraction spectrum is Ix and the intensity of the peak appearing in the region of 2θ=37 to 38 degrees is Iy, and Ix / Iy is the relative intensity of Ix when Iy is 1, it is preferably 0.140 or less, more preferably 0.120 or less, even more preferably 0.110 or less, still more preferably 0.080 or less, particularly preferably 0.060 or less, and especially preferably 0.040 or less, and is usually 0 or more, but the smaller the better.

[0079] The peak in the region of 2θ=37 to 38 degrees is one of the peaks characteristic of the main phase of the phosphor according to embodiment 1 or 2, and a red phosphor with higher phase purity can be obtained by having a relatively high Iy. When Ix / Iy is equal to or less than the upper limit, a phosphor with high phase purity and a narrow full width at half maximum (FWHM) in the emission spectrum can be obtained, thereby improving the luminous efficiency of the light-emitting device.

[0080] [Internal Quantum Efficiency of Red Phosphor] In one embodiment, the phosphor has an internal quantum efficiency of 30% or more. The internal quantum efficiency is preferably 35% or more, more preferably 40% or more, even more preferably 45% or more, particularly preferably 50% or more, and especially preferably 55% or more. There is no upper limit, and the higher the efficiency the better, but it is usually 100% or less.

[0081] The internal quantum efficiency of the red phosphor can be determined by a conventional method, for example, it can be calculated from an emission spectrum measured using a spectrophotometer.

[0082] [Emission Spectrum Characteristics] The phosphor according to embodiment 1 or 2 is excited by irradiation with light having an appropriate wavelength, and emits red light that exhibits a favorable emission peak wavelength and peak full width at half maximum (FWHM) in the emission spectrum. The emission spectrum, excitation wavelength, emission peak wavelength, and peak full width at half maximum (FWHM) in the emission spectrum will be described below.

[0083] (Excitation Wavelength) The phosphor according to embodiment 1 or 2 has an excitation peak in a wavelength range of usually 270 nm or more, preferably 300 nm or more, more preferably 320 nm or more, even more preferably 350 nm or more, particularly preferably 400 nm or more, and usually 550 nm or less, preferably 520 nm or less, more preferably 500 nm or less. That is, it is excited by light in the near ultraviolet to blue region.

[0084] The shape of the emission spectrum and the following descriptions of the emission peak wavelength and the peak half width in the emission spectrum are applicable regardless of the excitation wavelength. However, from the viewpoint of improving quantum efficiency, it is preferable to irradiate with light having a wavelength in the above-mentioned range, which has good absorption and excitation efficiency.

[0085] (Emission Peak Wavelength) In one embodiment, the emission spectrum of the red phosphor has an emission peak wavelength in the range of 620 nm or more and 660 nm or less.

[0086] In a specific embodiment, the emission spectrum of the red phosphor preferably includes at least one emission peak at 625 nm or more, more preferably at 630 nm or more, even more preferably at 635 nm or more, even more preferably at 640 nm or more, and extremely preferably at 645 nm or more. A light-emitting device including a red phosphor including at least one emission peak having an emission peak wavelength equal to or greater than the lower limit has good red color rendering or color reproducibility and is suitable for applications such as backlights for image display devices (displays). Alternatively, it can emit bright red light and is suitable for applications such as brake lamps.

[0087] In another specific embodiment, the emission spectrum preferably includes one or more emission peaks at 655 nm or less, more preferably 650 nm or less, even more preferably 648 nm or less, still more preferably 645 nm or less, particularly preferably 640 nm or less, and extremely preferably 637 nm or less. A red phosphor whose emission spectrum includes one or more emission peaks at or below the upper limit has low emission intensity in the wavelength region around 700 nm, where relative luminous efficiency is low, and a light-emitting device including such a red phosphor has good conversion efficiency and is suitable for use in, for example, a lighting device.

[0088] The method for adjusting the emission peak wavelength is not particularly limited, but for example, by adjusting the composition of the M C element, the emission peak wavelength can be adjusted while maintaining a narrow peak half width in the emission spectrum. In a specific embodiment, the emission peak wavelength can be adjusted to the long wavelength side by increasing the proportion of Al in M ​​C, and the emission peak wavelength can be adjusted to the short wavelength side by increasing the proportion of elements other than Al in part of M C in formula [1] or formula [2].

[0089] (Peak Half Width in Emission Spectrum) The phosphor according to embodiment 1 or 2 has a peak half width in the emission spectrum of usually 70 nm or less, preferably 65 nm or less, more preferably 60 nm or less, even more preferably 57 nm or less, particularly preferably 55 nm or less, and most preferably 50 nm or less, and is usually 10 nm or more.

[0090] By using a red phosphor whose emission spectrum has a half-peak width within the above range, it is possible to widen the color reproduction range without reducing the color purity in image display devices such as liquid crystal displays. Furthermore, by having an emission peak wavelength and an emission spectrum whose half-peak width are equal to or less than the above upper limits, it is possible to provide a red phosphor having a relatively high relative luminous efficiency in the emission wavelength region, and by using such a red phosphor in a light-emitting device, it is possible to provide a light-emitting device with high conversion efficiency.

[0091] In order to excite the red phosphor with light having a wavelength of about 450 nm, for example, a GaN-based LED can be used. Measurement of the emission spectrum of the red phosphor and calculation of its emission peak wavelength, peak relative intensity, and peak half-width in the emission spectrum can be performed using, for example, a commercially available spectrum measurement device, such as a fluorescence measurement device equipped with a light source having an emission wavelength of 300 to 400 nm, such as a commercially available xenon lamp, and a general photodetector.

[0092] In one embodiment of the light emitting device, it is preferable that the emission peak wavelength x (nm) and the peak half width y (nm) in the emission spectrum of the red phosphor satisfy the relationship y≦184−0.2x. By using a phosphor whose emission peak wavelength and peak half width satisfy the above formula, the conversion efficiency of the light emitting device can be improved.

[0093] <Method for Producing Phosphor> The phosphor of this embodiment can be synthesized by mixing raw materials of the elements constituting the phosphor so that the ratio of the elements satisfies the above formula [1] or formula [2], and heating the mixture.

[0094] [Phosphor Raw Materials] The phosphor raw materials that serve as the supply sources of each element (MA, MB, MC, Re, MY, MZ, MW) are not particularly limited, and examples thereof include simple substances of each element, oxides, nitrides, hydroxides, halides such as chlorides and fluorides, inorganic salts such as sulfates, nitrates and phosphates, and organic acid salts such as acetates. Compounds containing two or more of the above element groups may also be used. Each compound may also be a hydrate. In the examples described below, nitrides were used for elements other than MW, and fluorides were used for the MW element as phosphor raw materials.

[0095] There is no particular limitation on the method for obtaining each phosphor raw material, and commercially available products can be purchased and used.

[0096] The purity of each phosphor raw material is not particularly limited, but from the viewpoint of ensuring strict element ratios and avoiding the appearance of different phases due to impurities, the higher the purity, the better, and it is usually 90 mol% or more, preferably 95 mol% or more, more preferably 97 mol% or more, and even more preferably 99 mol% or more, and although there is no particular upper limit, it is usually 100 mol% or less, and it may contain impurities that are inevitably mixed in. In the examples described below, phosphor raw materials with a purity of 95 mol% or more were used.

[0097] The oxygen (O), nitrogen (N) or halogen element that can be contained in the D element can be supplied by using oxides, nitrides, halides, etc. as phosphor raw materials that serve as sources of the respective elements, or can be appropriately contained by creating an oxygen- or nitrogen-containing atmosphere during the synthesis reaction.

[0098] [Mixing Step] The method for mixing the phosphor raw materials is not particularly limited, and conventional methods can be used. For example, the phosphor raw materials are weighed so as to obtain the desired composition, and then thoroughly mixed using a ball mill or the like to obtain a phosphor raw material mixture. The mixing method is not particularly limited, but specific examples include the following methods (a) and (b). (a) A dry mixing method in which the phosphor raw materials are pulverized and mixed using a dry pulverizer such as a hammer mill, roll mill, ball mill, or jet mill, or a mortar and pestle, combined with mixing using a mixer such as a ribbon blender, V-type blender, or Henschel mixer, or a mortar and pestle. (b) A wet mixing method in which a solvent or dispersion medium such as water is added to the phosphor raw materials, and the mixture is mixed using, for example, a pulverizer, a mortar and pestle, or an evaporating dish and a stirring rod to form a solution or slurry, which is then dried by spray drying, heat drying, natural drying, or the like.

[0099] The phosphor raw materials may be mixed by either the dry mixing method or the wet mixing method, but in order to avoid contamination of the phosphor raw materials by moisture, the dry mixing method or the wet mixing method using a non-aqueous solvent is preferred. Note that in the examples described below, method (a) was adopted.

[0100] [Heating Step] In the heating step (hereinafter also referred to as the firing step), for example, the mixture of phosphor raw materials obtained in the mixing step is placed in a crucible, and then heated at a temperature of 500° C. to 1200° C. The temperature in the heating step is preferably 600° C. or higher, more preferably 700° C. or higher, and is preferably 1000° C. or lower, more preferably 950° C. or lower, and may be 900° C. or lower.

[0101] By lowering the heating temperature (hereinafter sometimes referred to as the firing temperature), particularly to 950° C. or lower, a phosphor with a high phase purity and high luminescence intensity of the composition represented by formula [1] can be obtained. The reason for this is that at high temperatures such as 1000° C. or higher or 1100° C. or higher, substances containing Li, Mg, Na, etc., which have high vapor pressures, tend to volatilize, and the ratio of each element is likely to fluctuate in the phosphor synthesis reaction. However, by performing the synthesis at a low temperature such as 950° C. or lower, it is possible to suppress fluctuations in the ratio of each element.

[0102] The pressure in the heating step may be either normal pressure or pressurized as long as the desired phosphor is obtained, but pressurization is preferred to prevent volatilization of elements contained in the phosphor raw material. When pressurization is used, the pressure is usually 0.1 MPa or more and 200 MPa or less, preferably 100 MPa or less. By keeping the pressure within the above range, good reactivity of the phosphor raw material can be ensured.

[0103] The method of pressurization is not limited, and for example, a method of heating a sealed container, a method of mechanically pressurizing, or a method using gas pressure can be used.

[0104] The material of the crucible is preferably one that does not react with the phosphor raw material or reactant, and examples thereof include ceramics such as alumina, quartz, boron nitride, silicon carbide, and silicon nitride, metals such as nickel (Ni), platinum (Pt), molybdenum (Mo), tungsten (W), tantalum (Ta), niobium (Nb), iridium (Ir), and rhodium (Rh), and alloys containing these as the main components.

[0105] Heating is preferably carried out in an inert atmosphere, and gases containing nitrogen, argon, helium, etc. as the main component can be used. In the examples described later, heating was carried out in a nitrogen atmosphere.

[0106] In the heating step, heating is performed in the above temperature range for typically 10 minutes to 200 hours, preferably 1 hour to 100 hours, and more preferably 2 hours to 50 hours. This heating step may be performed once or multiple times. Examples of a heating step performed multiple times include an annealing step in which heating is performed under pressure to repair defects, and a secondary heating step in which secondary particles or a final product are obtained after primary heating to obtain primary particles or an intermediate. This results in the phosphor of this embodiment.

[0107] <Light-emitting device> In one embodiment, the present invention provides a light-emitting device comprising a first light-emitting body and a second light-emitting body that emits visible light when irradiated with light from the first light-emitting body, wherein the second light-emitting body comprises a phosphor according to embodiment 1 or 2. The descriptions relating to the phosphor described above can be applied to the respective configurations and characteristics of the phosphor according to embodiment 1 or 2 included in the light-emitting device of this embodiment. Here, the second light-emitting body may comprise one type of phosphor alone, or two or more types of phosphors may be used in any combination and ratio. Furthermore, the second light-emitting body may comprise a phosphor other than the phosphor according to embodiment 1 or 2.

[0108] The light emitting device of this embodiment includes, as the second light emitting body, at least the phosphor according to embodiment 1 or 2, and can further use a yellow phosphor that emits yellow fluorescence, a green phosphor that emits green fluorescence, or a red phosphor that emits fluorescence in the red region (orange to red) (a red phosphor different from the phosphor according to embodiment 1 or 2) under irradiation with light from an excitation light source. In a specific embodiment, the light emitting device according to the present invention is a light emitting device in which the second light emitting body further includes a yellow phosphor and / or a green phosphor.

[0109] Specifically, when configuring a light emitting device, the yellow phosphor preferably has an emission peak in the wavelength range of 550 nm to 600 nm, and the green phosphor preferably has an emission peak in the wavelength range of 500 nm to 560 nm. The orange to red phosphor has an emission peak in the wavelength range of usually 615 nm or more, preferably 620 nm or more, more preferably 625 nm or more, and even more preferably 630 nm or more, and usually 660 nm or less, preferably 650 nm or less, more preferably 645 nm or less, and even more preferably 640 nm or less.

[0110] By appropriately combining phosphors in the above wavelength ranges, a light emitting device exhibiting excellent color reproducibility can be provided. Note that the excitation light source may have an emission peak in a wavelength range of less than 420 nm.

[0111] Hereinafter, the configuration of the light emitting device will be described in the case where at least the phosphor according to the first or second embodiment is used as the red phosphor, but the present embodiment is not limited to these.

[0112] In the above case, the light emitting device of this embodiment can be, for example, in the following form (X), (Y), or (Z): (X) An aspect comprising a first light emitting body and a second light emitting body, wherein the second light emitting body comprises at least the phosphor according to the first or second embodiment and further comprises at least one phosphor (yellow phosphor) having an emission peak in a wavelength range of 550 nm to 600 nm; (Y) An aspect comprising a first light emitting body and a second light emitting body, wherein the second light emitting body comprises at least the phosphor according to the first or second embodiment and further comprises at least one phosphor (green phosphor) having an emission peak in a wavelength range of 500 nm to 560 nm; (Z) An aspect comprising a first light emitting body and a second light emitting body, wherein the second light emitting body comprises at least the phosphor according to the first or second embodiment and further comprises at least one phosphor (yellow phosphor) having an emission peak in a wavelength range of 550 nm to 600 nm and at least one phosphor (green phosphor) having an emission peak in a wavelength range of 500 nm to 560 nm.

[0113] The yellow phosphor and / or green phosphor in the above embodiment can be commercially available, such as a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, an oxynitride phosphor, etc. In a specific embodiment, the yellow phosphor and / or green phosphor includes one or more phosphors selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

[0114] (Yellow Phosphor) Examples of garnet-based phosphors that can be used as the yellow phosphor include (Y, Gd, Lu, Tb, La) ３ (Al, Ga) ５ O １２ : (Ce, Eu, Nd), and silicate-based phosphors such as (Ba, Sr, Ca, Mg) ２ SiO ４ : (Eu, Ce), nitride phosphors and oxynitride phosphors include, for example, (Ba, Ca, Mg)Si２ O ２ N ２ : Eu (SiON-based phosphor), (Li, Ca) ２ (Si, Al) １２ (O, N) １６ : (Ce, Eu) (α-sialon phosphor), (Ca, Sr)AlSi ４ (O, N) ７ : (Ce, Eu) (1147 phosphor), (La, Ca, Y, Gd) ３ (Al, Si) ６ N １１ :(Ce,Eu)(LSN phosphor), etc. These may be used alone or in combination of two or more.

[0115] As the yellow phosphor, garnet-based phosphors are preferred among the above phosphors, and among them, Y ３ Al ５ O １２ A YAG-based phosphor represented by the formula:Ce is most preferred.

[0116] (Green Phosphor) Examples of garnet-based phosphors that can be used as the green phosphor include (Y, Gd, Lu, Tb, La) ３ (Al, Ga) ５ O １２ : (Ce, Eu, Nd), Ca ３ (Sc, Mg) ２ Si ３ O １２ : (Ce, Eu) (CSMS phosphor), and silicate-based phosphors include, for example, (Ba, Sr, Ca, Mg) ３ SiO １０ : (Eu, Ce), (Ba, Sr, Ca, Mg) ２ SiO ４ : (Ce, Eu) (BSS phosphor), and oxide phosphors such as (Ca, Sr, Ba, Mg) (Sc, Zn) ２ O ４ : (Ce, Eu) (CASO phosphor), nitride phosphors and oxynitride phosphors include, for example, (Ba, Sr, Ca, Mg)Si ２ O ２ N ２ : (Eu, Ce), Si ６－ｚ Al ｚ Oｚ N ８－ｚ : (Eu, Ce) (β-sialon phosphor) (0 < z ≦ 1), (Ba, Sr, Ca, Mg, La) ３ (Si, Al) ６ O １２ N ２ : (Eu, Ce) (BSON phosphor), (La, Ca, Y, Gd) ３ (Al, Si) ６ N １１ :(Ce,Eu)(LSN phosphor), etc. These may be used alone or in combination of two or more.

[0117] (Red Phosphor) As the red phosphor, at least the phosphor according to the first or second embodiment is used. In addition to the phosphor of this embodiment, other orange or red phosphors such as garnet-based phosphors, sulfide phosphors, nanoparticle phosphors, nitride phosphors, and oxynitride phosphors can be used. As other orange or red phosphors, for example, the following phosphors can be used. As sulfide phosphors, for example, (Sr, Ca)S:Eu (CAS phosphor), La ２ O ２ S:Eu (LOS phosphor), garnet-based phosphors include, for example, (Y, Lu, Gd, Tb) ３ Mg ２ AlSi ２ O １２ : Ce, nanoparticles such as CdSe, nitride or oxynitride phosphors such as (Sr,Ca)AlSiN ３ : Eu (S / CASN phosphor), (CaAlSiN ３ ) １－ｘ (SiO ２ N ２ ) ｘ : Eu (CASON phosphor), (La, Ca) ３ (Al, Si) ６ N １１ : Eu (LSN phosphor), (Ca, Sr, Ba) ２ Si ５ (N, O) ８ : Eu (258 phosphor), (Sr, Ca) Al １＋ｘ Si ４－ｘ O ｘ N７－ｘ : Eu (1147 phosphor), M ｘ (Si, Al) １２ (O, N) １６ : Eu (M is Ca, Sr, etc.) (α-sialon phosphor), Li(Sr,Ba)Al ３ N ４ :Eu (wherein x is 0<x<1 in all cases). These may be used alone or in combination of two or more.

[0118] [Configuration of the Light-Emitting Device] The light-emitting device according to this embodiment has a first light-emitting body (excitation light source), and can use at least the phosphor according to the first or second embodiment as the second light-emitting body. The configuration is not limited, and any known device configuration can be used.

[0119] The first light emitter may be an LED element having a light emitting structure formed of various semiconductors such as a GaN-based semiconductor, a ZnO-based semiconductor, or a SiC-based semiconductor.

[0120] Examples of device configurations and light-emitting device embodiments include those described in Japanese Patent Application Laid-Open No. 2007-291352. Alternatively, the LED element may be fixed to a package such as a bullet-type package or an SMD-type package, or directly fixed to a circuit board, as in the case of a chip-on-board light-emitting device. The form of optical coupling between the LED element and the phosphor is not limited; the space between them may simply be filled with a transparent medium (including air), or an optical element such as a lens, optical fiber, light guide plate, or reflecting mirror may be interposed between them. A structure in which phosphor particles are dispersed in a translucent matrix is ​​typically formed by curing a resin paste in which particulate phosphor is dispersed. In addition to a structure in which the LED element is embedded in the cured paste, various structures are possible, such as a structure in which the cured product covers a portion of the surface of the LED element in a film-like form, or a structure in which a film made of the cured product is disposed at a location separate from the LED element.

[0121] {Uses of Light-Emitting Devices} The uses of light-emitting devices are not particularly limited, and they can be used in various fields in which ordinary light-emitting devices are used, but light-emitting devices with high color rendering properties can be particularly suitably used as light sources for lighting devices and image display devices. Furthermore, light-emitting devices including a red phosphor with a good emission wavelength can be used in red vehicle indicator lights or vehicle indicator lights that emit white light containing the red light.

[0122] [Lighting Device] In one embodiment, the present invention may provide a lighting device including the light-emitting device as a light source.

[0123] When the light-emitting device is applied to a lighting device, there is no limitation on the specific configuration of the lighting device, and the light-emitting device as described above may be appropriately incorporated into a known lighting device for use. For example, a surface-emitting lighting device in which a number of light-emitting devices are arranged on the bottom surface of a holding case may be mentioned.

[0124] [Image Display Device] In one embodiment, the present invention may be an image display device including the light emitting device as a light source.

[0125] When the light emitting device is used as a light source for an image display device, the specific configuration of the image display device is not limited, but it is preferable to use it together with a color filter. For example, when the image display device is a color image display device using a color liquid crystal display element, the image display device can be formed by using the light emitting device as a backlight and combining it with an optical shutter using a liquid crystal and a color filter having red, green, and blue pixels.

[0126] [Vehicle Indicator Light] In one embodiment, the present invention may provide a vehicle indicator light including the light-emitting device as a light source.

[0127] In a specific embodiment, the light-emitting device used in the vehicle indicator lamp is preferably a light-emitting device that emits white light. In the light-emitting device that emits white light, the deviation duv (also referred to as Δuv) of the light color from the blackbody radiation locus is preferably −0.0200 to 0.0200, and the color temperature is preferably 5000 K or more and 30000 K or less.

[0128] In a specific embodiment, the light emitting device used in the vehicle indicator light is preferably a light emitting device that emits red light. In this embodiment, for example, the light emitting device may absorb blue light irradiated from a blue LED chip and emit red light, thereby forming a red light vehicle indicator light.

[0129] Vehicle indicator lights include headlights, side lights, back lights, turn signals, brake lights, fog lights, and other lighting provided on a vehicle for the purpose of providing some kind of indication to other vehicles, people, etc.

[0130] Hereinafter, several specific embodiments of the present invention will be described with reference to examples, but the present invention is not limited to the following as long as it does not deviate from the gist of the present invention.

[0131] {Measurement Method} [Measurement of Emission Spectrum] The emission spectrum was measured using a spectrofluorometer FP8500 (manufactured by JASCO Corporation) under the following measurement conditions: Light source: xenon lamp Excitation wavelength: 455 nm Measurement wavelength range: 380 to 780 nm Measurement interval: 1.0 nm The chromaticity coordinate values ​​were calculated from the emission spectrum data from 480 nm to 780 nm using the CIE 1931 XYZ equation function.

[0132] [Measurement of Reflectance] Reflectance was measured using an ultraviolet-visible spectrophotometer (V-750, manufactured by JASCO Corporation) under the following measurement conditions: Reflectance is the reflectance value for light of 455 nm, with a standard reflector being taken as 100%. Light source: deuterium lamp, halogen lamp Measurement wavelength range: 380 to 780 nm Measurement interval: 1.0 nm

[0133] [Unit Cell Volume] The unit cell volume was calculated by X-ray diffraction (XRD) and Rietveld structural analysis. XRD was precisely measured using a powder X-ray diffractometer, X'Pert PRO MPD (manufactured by PANalytical). The measurement conditions were as follows: - CuKα tube used - X-ray output = 45 kV, 40 mA - Divergence slit = automatic - Detector = high-speed semiconductor array detector X'Celerator - Search range 2θ = 10 to 150 degrees - Reading width = 0.008 degrees The Rietveld analysis software "RIETAN-FP" was used to refine the lattice constants and calculate the unit cell volume.

[0134] [Spectral efficiency in the red region] The emission spectral efficiency in the red region was evaluated by integrating the product of the emission intensity for each wavelength from 550 to 780 nm and the bright light luminous efficiency, dividing the integrated value by the emission intensity for each wavelength from 550 to 780 nm alone, and multiplying the resulting value by the maximum bright light luminous efficiency of 683 Lm / W.

[0135] <Production of Phosphor> [Comparative Example 1] An exemplary red phosphor for use in a light-emitting device according to one embodiment of the present invention or a comparative example was produced. Referring to JP 2017-008130 A and Chemistry of Materials 2019 31 (12), 4614-4618, nitrides of each element were dry-mixed so that the molar ratio of each element was the ratio shown in Table 1, and the mixture was placed in a boron nitride crucible, which was then placed in a firing furnace. The atmosphere in the firing furnace was replaced with nitrogen gas, the nitrogen gas pressure was adjusted to 0.9 MPa, and the furnace was heated to 850°C and held at 850°C for 5 hours, thereby producing the phosphor according to Comparative Example 1.

[0136] [Examples 1 to 4] The phosphors of Examples 1 to 4 were manufactured in the same manner as in Comparative Example 1, except that La, Na, and K raw materials were used appropriately and the raw materials were mixed so that the molar ratios of each element were as shown in Table 1.

[0137]

[0138] [Comparative Example 2, Examples 5 to 8] Phosphors according to Comparative Example 2 and Examples 5 to 8 were produced in the same manner as in Comparative Example 1, except that raw materials were mixed so that the molar ratios of each element were as shown in Table 2, and the temperature inside the firing furnace was changed to 830°C. Table 3 shows the results of component analysis of the phosphors according to Comparative Example 2 and Examples 5 to 8 by SEM-EDS. The conditions for SEM-EDS were as follows: Apparatus: Hitachi S-3400N and Thermo Fisher Scientific Noran System Measurement conditions: BSE image, acceleration voltage 20 kV, low vacuum (90 Pa) Analysis: EDS measurement was performed on samples with two fields of view and n numbers of 29 to 41. In the atomic ratios (at%) of the measurement results, the Sr composition ratio and La composition ratio were calculated based on the total composition ratio of Al + Ga.

[0139]

[0140]

[0141] Table 4 shows various properties of the phosphors according to Comparative Example 1 and Examples 1 to 4. Table 5 shows various properties of the phosphors according to Comparative Example 2 and Examples 5 to 8. Furthermore, the emission spectra of the phosphors according to Comparative Example 1 and Examples 1 to 4, normalized with the maximum emission intensity set to 1.0, and their enlarged views are shown in FIGS. 1A and 1B, respectively. Furthermore, Table 4 and FIG. 2 show the unit cell volumes of the phosphors according to Comparative Example 1 and Examples 1 to 4.

[0142] When the components of the phosphor according to Example 3 were analyzed by a scanning electron microscope (SEM)-EDX (energy dispersive X-ray spectroscopy) technique, the molar ratio of each element was Sr:La:Al:Ga = 0.89:0.14:2.03:0.92, which was almost the same as the mixing ratio of the raw materials. The powder X-ray diffraction patterns of the phosphors according to Examples 1 to 4 were all SrLiAl ３ N ４ Since the results showed good agreement with the molar ratio of Al:Eu, it was estimated that the molar ratio of nitrogen atoms was approximately 4 when the total molar ratio of Al and Ga was 3. Since the unit cell volume changed and the molar ratio of the elements reflected the ratio at the time of mixing the raw materials, it is believed that the solid solution substitution of MA with MY occurred as intended.

[0143] As can be seen from Table 3, the molar ratios of the elements in the phosphors according to Comparative Example 2 and Examples 5 to 8 were almost the same as the mixing ratios of the raw materials. Note that although La is not 0 in Comparative Example 2, this is a baseline, and it can be considered that La is not contained in the phosphor according to Comparative Example 2.

[0144]

[0145]

[0146] As can be seen from Table 4, the phosphors according to Examples 1 to 4 all have significantly improved excitation light absorption efficiency and significantly improved spectral efficiency in the red region compared to the phosphor according to Comparative Example 1. In addition, the unit cell volume has changed, which is thought to be due to the presence of a different element from that in the phosphor according to Comparative Example 1, namely, MY, MZ, or MW, in solid solution.

[0147] As can be seen from Table 5, the phosphors according to Examples 5 to 8 all had significantly improved excitation light absorption efficiency compared to the phosphor according to Comparative Example 2. In addition, the unit cell volume changed, which is thought to be due to the presence of a different element from that in the phosphor according to Comparative Example 2, namely, MY, in solid solution.

[0148] As described above, according to the present embodiment, it is possible to provide a phosphor having a good emission peak wavelength and / or good excitation light absorption efficiency. Furthermore, by including such a phosphor, it is possible to provide a light-emitting device, a lighting device, an image display device, and / or a vehicle indicator lamp having good color rendering properties or color reproducibility and good conversion efficiency.

[0149] Although various embodiments have been described above, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any manner as long as they do not deviate from the spirit of the invention.

[0150] This application is based on a Japanese patent application (Patent Application No. 2023-194412) filed on November 15, 2023, the contents of which are incorporated herein by reference.

[0151] The phosphor of the present invention is a red phosphor that has an appropriate emission peak wavelength and efficiently converts excitation light into emitted light, and can provide a light-emitting device with good conversion efficiency, so it can be used in lighting devices, image display devices, vehicle indicator lights, etc.

Claims

1. A phosphor comprising a crystalline phase having a composition represented by the following formula [1]: MA ａ－ｘ－ｙ－ｚ R ｘ M.Y. ｙ M.Z. ｚ MB ｂ M.C. ３－ｗ M.W. ｗ D ｄ [1] (In the above formula [1], MA includes one or more elements selected from the group consisting of Sr, Ca, and Ba, MB includes Li, MC includes one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc, D includes one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes N (nitrogen), Re includes one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb, MY includes one or more elements selected from the group consisting of Y, La, and Lu, MZ includes one or more elements selected from the group consisting of Na, K, and Rb, MW includes one or more elements selected from the group consisting of Mg and Zn, a, b, d, x, y, z, and w each independently satisfy the following formula: 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦z≦0.5 0.0<x+y+z<a 0.0≦w≦0.5) 2. A phosphor comprising a crystalline phase having a composition represented by the following formula [2]: MA ａ－ｘ－ｙ R ｘ M.Y. ｙ MB ｂ＋ｖ１ M.C. ３－ｖ２ D ｄ [2] (In the above formula [2], MA includes one or more elements selected from the group consisting of Sr, Ca, and Ba; MB includes Li; MC includes one or more elements selected from the group consisting of B (boron), Al, Si, Ga, In, and Sc; D includes one or more elements selected from the group consisting of N (nitrogen), O (oxygen), F (fluorine), Cl, Br, and I (iodine), and includes N (nitrogen); Re includes one or more elements selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Tb, Dy, Ho, Er, Tm, and Yb; MY includes one or more elements selected from the group consisting of Y, La, and Lu; and a, b, d, x, y, v1, and v2 each independently satisfy the following formula. 0.7≦a≦1.3 0.7≦b≦1.3 3.2≦d≦4.8 0.0<x≦0.2 0.0<y≦0.5 0.0≦v1≦y 0.0≦v2≦y 0.5y≦v1+v2≦1.5y) 3. The phosphor according to claim 1 or 2, wherein MC contains at least Al and Ga.

4. The crystal structure of the crystal phase having the composition represented by the formula [1] or [2] is SrLiAl ３ N ４ The phosphor according to claim 1 or 2, wherein 5. The phosphor according to claim 1 or 2, which has an emission peak wavelength in the range of 620 nm or more and 660 nm or less in its emission spectrum.

6. A light emitting device comprising a first light emitting body and a second light emitting body that emits visible light when irradiated with light from the first light emitting body, wherein the second light emitting body comprises the phosphor according to claim 1 or 2.

7. The light emitting device according to claim 6, wherein the second luminescent material further comprises a yellow phosphor and / or a green phosphor.

8. The light emitting device according to claim 7, wherein the yellow phosphor and / or the green phosphor comprises at least one selected from the group consisting of a garnet-based phosphor, a silicate-based phosphor, a nitride phosphor, and an oxynitride phosphor.

9. A lighting device comprising the light-emitting device according to claim 6 as a light source.

10. An image display device comprising the light emitting device according to claim 6 as a light source.

11. A vehicle indicator lamp comprising the light emitting device according to claim 6 as a light source.