Abstract: A light emitting device according to embodiments includes a light emitting element emitting light with a peak wavelength of 420˜445 nm, a first phosphor emitting light with a peak wavelength of 485˜530 nm, a second phosphor emitting light with a peak wavelength of 530˜580 nm, and a third phosphor emitting light with a peak wavelength of 600˜650 nm. The device emits light having an emission spectrum that has a local minimum value of light intensity between a wavelength of 450˜470 nm or less, the local minimum value being 60% or less of a maximum value of light intensity at a longer wavelength side from the local minimum value, and the device emits light having a color temperature of 4600 K or higher and 5400 K or less.

Abstract: The fluorescent substance according to the present disclosure emits luminescence with a peak in the wavelength range of 500 to 600 nm under excitation by light with a peak in the wavelength range of 250 to 500 nm, and has an optical absorption coefficient ?560nm of 4×10?5 or less at 560 nm. The substance is represented by the following formula (1): (M1-xCex)2yAlzSi10-zOuNw??(1). In the formula, M is a metal element selected from the group consisting of Ba, Sr, Ca, Mg, Li, Na and K; and x, y, z, u and w are variables satisfying the conditions of 0<x?1, 0.8?y?1.1, 2?z?3.5, u?1, 1.8?z?u and 13?u+w?15, respectively.

Abstract: According to one embodiment, the luminescent material shows a luminescence peak in a wavelength range of 570 to 670 nm when excited with light having an emission peak in a wavelength range of 250 to 520 nm. The luminescent material includes a host material having a crystal structure substantially same as the crystal structure of Sr2Si7Al3ON13. The host material is activated by Eu, and includes Sr and Ca to satisfy a relationship of 0.008?MCa/(MSr+MCa)?0.114, where MCa is a number of moles of Ca and MSr is a number of moles of Sr.

Abstract: According to one embodiment, the phosphor exhibits a luminescence peak in a wavelength ranging from 500 to 600 nm when excited with light having an emission peak in a wavelength ranging from 250 to 500 nm. The phosphor has a composition represented by (M1-xCex)2yAlzSi10-zOuNw (M represents Sr and a part of Sr may be substituted by at least one selected from Ba, Ca, and Mg; x, y, z, u, and w satisfy 0<x?1, 0.8?y?1.1, 2?z?3.5, 0<u?1, 1.8?z?u, and 13?u+w?15). The phosphor has a crystalline aspect ratio of 1.5 to 10.

Abstract: A light emitting device includes a light emitting element that emits light having a wavelength of 250 nm to 500 nm and a fluorescent layer that is disposed on the light emitting element. The fluorescent layer includes a phosphor having a composition expressed by the equation, ((M1?x1Eux1)3?ySi13?zAl3+zO2+uN21?w), and an average particle diameter of 12 ?m or more, wherein in the equation, M is an element that is selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al, rare-earth elements, and IVB group elements, and x1, y, z, u, and w satisfy each of the inequalities simultaneously, that is to say each of the following inequalities is satisfied by the choice of values of the identified paramaters within the noted ranges of 0<x1<1, ?0.1<y<0.3, ?3<z?1, ?3<u?w?1.5, 2<u, w<21.

Abstract: The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1): (M1-xECx)aM1bAlOcNd??(1). In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; M1 is different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0<x<0.2, 0.55<a<0.80, 2.10<b<3.90, 0<c?0.25 and 4<d<5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.

Abstract: The present invention provides a fluorescent substance excellent both in quantum efficiency and in temperature characteristics, and also provides a process for producing the fluorescent substance. This fluorescent substance is an oxynitride phosphor having a low paramagnetic defect density and comprising aluminum, silicon, either or both of oxygen and nitrogen, and a metal element M, provided that the metal element M is partly replaced with an emission center element R. That phosphor can be produced by the steps of: subjecting a mixture of starting materials to heat treatment under a nitrogen atmosphere so as to obtain an intermediate fired product, and then further subjecting the intermediate fired product to heat treatment under an atmosphere of nitrogen-hydrogen mixed gas.

Abstract: The present invention provides a fluorescent substance excellent both in quantum efficiency and in temperature characteristics, and also provides a process for producing the fluorescent substance. This fluorescent substance is an oxynitride phosphor having a low paramagnetic defect density and comprising aluminum, silicon, either or both of oxygen and nitrogen, and a metal element M, provided that the metal element M is partly replaced with an emission center element R. That phosphor can be produced by the steps of: subjecting a mixture of starting materials to heat treatment under a nitrogen atmosphere so as to obtain an intermediate fired product, and then further subjecting the intermediate fired product to heat treatment under an atmosphere of nitrogen-hydrogen mixed gas.

Abstract: A light emitting device according to one embodiment includes a board; a light emitting element mounted on the board, emitting light having a wavelength of 250 nm to 500 nm; a red fluorescent layer formed on the element, including a red phosphor expressed by equation (1), having a semicircular shape with a diameter r; (M1?x1Eux1)aSibAlOcNd??(1) (In the equation (1), M is an element that is selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al (Aliminum), rare-earth elements, and IVB group elements), an intermediate layer formed on the red fluorescent layer, being made of transparent resin, having a semicircular shape with a diameter D; and a green fluorescent layer formed on the intermediate layer, including a green phosphor, having a semicircular shape. A relationship between the diameter r and the diameter D satisfies equation (2): 2.0r(?m)?D?(r+1000)(?m).

Abstract: According to one embodiment, the phosphor exhibits a luminescence peak in a wavelength ranging from 500 to 600 nm when excited with light having an emission peak in a wavelength ranging from 250 to 500 nm. The phosphor has a composition represented by (M1-xCex)2yAlzSi10-zOuNw (M represents Sr and a part of Sr may be substituted by at least one selected from Ba, Ca, and Mg; x, y, z, u, and w satisfy 0<x?1, 0.8?y?1.1, 2?z?3.5, 0<u?1, 1.8?z?u, and 13?u+w?15). The phosphor has a crystalline aspect ratio of 1.5 to 10.

Abstract: According to one embodiment, the phosphor exhibits a luminescence peak within a wavelength range of 500 to 600 nm when it is excited with light having an emission peak within a wavelength range of 250 to 500 nm. The phosphor has a composition represented by (M1-xCex)2yAlzSi10-zOuNwBs (M represents Sr and a part of Sr may be substituted by at least one selected from the group consisting of Ba, Ca and Mg; and x, y, z, u, w and s satisfy 0<x?1, 0.8?y?1.1, 2?z?3.5, 1<u?1, 1.5?z?u, 13?u+w?15, and 0<s<0.245.

Abstract: The embodiment provides a process for production of an oxynitride fluorescent substance. In the process, a compound represented by the formula: (Sr,Eu)2Si5N8, silicon nitride and aluminum nitride are mixed and then fired in a nitrogen atmosphere under high pressure.

Abstract: The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1): (M1-xECx)aM1bAlOcNd??(1). In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; M1 is different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0<x<0.2, 0.55<a<0.80, 2.10<b<3.90, 0<c?0.25 and 4<d<5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.

Abstract: A light emitting device according to embodiments includes a light emitting element emitting light having a peak wavelength of 425 nm or more and 465 nm or less, a first phosphor emitting light having a peak wavelength of 485 nm or more and 530 nm or less, a second phosphor emitting light having a peak wavelength longer than that of the first phosphor, and a third phosphor emitting light having a peak wavelength longer than that of the second phosphor. Then, when the peak wavelength of the light emitting element is ?0 (nm) and the peak wavelength of the first phosphor is ?1 (nm), a relation of 30??1??0?70 is satisfied.

Abstract: The present embodiments provide a yellow light-emitting fluorescent substance of high luminous efficiency and also a production method thereof. This substance is represented by the formula (1): (M1-xREx)2yAlzSi10-zOuNw ??(1) (in the formula, M is at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Li, Na and K), and emits luminescence with a peak within 500 to 600 nm when excited by light of 250 to 500 nm. In the emission spectrum of the substance, the emission band with the above peak has a half-width corresponding to an energy difference of 0.457 eV or less. The substance can be obtained by pulverizing a material mixture so that the D90 value may be 5 ?m or less and then by firing the pulverized mixture.

Abstract: The embodiment provides a red light-emitting fluorescent substance represented by the following formula (1): (M1-xECx)aM1bAlOcNd??(1). In the formula (1), M is an element selected from the group consisting of IA group elements, IIA group elements, IIIA group elements, IIIB group elements, rare earth elements and IVA group elements; EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, Tl, Pb, Bi and Fe; M1 is different from M and is selected from the group consisting of tetravalent elements; and x, a, b, c and d are numbers satisfying the conditions of 0<x<0.2, 0.55<a<0.80, 2.10<b<3.90, 0<c?0.25 and 4<d<5, respectively. This substance emits luminescence having a peak in the wavelength range of 620 to 670 nm when excited by light of 250 to 500 nm.

Abstract: The present disclosure provides a phosphor excellent in temperature characteristic and capable of highly efficiently emitting yellow light with a wide half-width in the emission spectrum. This phosphor emits luminescence with a peak wavelength of 500 to 600 nm under excitation by light with a peak wavelength of 250 to 500 nm, and is represented by the following formula (1): (M1-xCex)2yAlzSi10-zOuNvCw??(1) [M is mainly Sr and may be partly replaced with at least one element selected from the group consisting of Ba, Ca and Mg; and x, y, z, u, v and w satisfy the conditions of 0<x?1, 0.8?y?1.1, 2?z?3.5, 0<u?1.5, 0.01?w?0.1 and 13?u+v+w?15, respectively].

Abstract: The embodiment of the present disclosure provides yellow luminescent substance having high luminous efficiency. This fluorescent substance is represented by the formula (1): (M1-xREx)2yAlzSi10-zOuNwCla??(1) (in the formula, M is at least one element selected from the group consisting of Ba, Sr, Ca, Mg, Li, Na and K), and it emits luminescence with a peak within 500 to 600 nm when excited by light of 250 to 500 nm.

Abstract: The embodiment of the present disclosure provides a phosphor having such high luminous efficiency as to be capable of realizing a light-emitting device suffering less from color drift even when working with high power. This phosphor is a Ce-activated phosphor having a crystal structure of Sr2Si7Al3ON13, and emitting luminescence with a peak wavelength of 500 to 600 nm under excitation by light with a peak wavelength of 250 to 500 nm. The XRD profile of the phosphor measured with Cu—K? line radiation according to Bragg-Brendano method shows diffraction lines having the intensities I0 and I1 at diffraction angles 2?s in the ranges of 31.55-31.85° and 24.75-250.5°, respectively, on the condition that the ratio of I1/I0 is 0.24 or less.

Abstract: A light-emitting device of an embodiment includes a light-emitting element emitting blue excitation light and a first phosphor excited by the blue excitation light and emitting fluorescence. A peak wavelength of the fluorescence is not shorter than 520 nm and shorter than 660 nm and the peak wavelength of the fluorescence shifting in the same direction when a peak wavelength of the blue excitation light shifts. The first phosphor is one of a yellow phosphor emitting yellow fluorescence, a green phosphor emitting green fluorescence, a yellow-green/yellow phosphor emitting yellow-green/yellow fluorescence and a red phosphor emitting red fluorescence.