Abstract: In one embodiment, an antibacterial material includes at least one microparticles selected from tungsten oxide microparticles and tungsten oxide complex microparticles. The microparticles, which have undergone a test to evaluate viable cell count by inoculating in a test piece, to which the microparticles are adhered in a range of 0.02 mg/cm2 or more and 40 mg/cm2 or less, at least one bacterium selected from among Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and enterohemorrhagic Escherichia coli, and storing for 24 hours, have an antibacterial activity value R of 0.1 or more expressed by the following: R=log(B1/C1) where, B1 denotes an average value (number) of viable cell count after storing an untreated test piece for 24 hours, and C1 denotes an average value (number) of viable cell count after storing the test piece on which the microparticles are coated for 24 hours.

Abstract: A phosphor according to an embodiment is a europium-activated alkaline-earth chloroapatite phosphor having a composition expressed by a composition formula: (M1-xEux)5(PO4)3Cl, where M is an alkaline-earth element containing at least Sr and Ba, x is an atomic ratio satisfying 0.04?x?0.2. In the phosphor of this embodiment, absorptance of light at a wavelength of 400 nm is 90% or more, and absorptance of light at a wavelength of 650 nm is 2% or less.

Abstract: A phosphor has a composition represented by Chemical formula 1: 1.5Y2O3·2.5aAl2O3:Ce where a is a number satisfying 1.02<a<1.1.

Abstract: A white LED lamp including: a conductive portion; a light emitting diode chip mounted on the conductive portion, for emitting a primary light having a peak wavelength of 360 nm to 420 nm; a transparent resin layer including a first hardened transparent resin, for sealing the light emitting diode chip; and a phosphor layer covering the transparent resin layer, the phosphor layer being formed by dispersing a phosphor powder into a second hardened transparent resin, and the phosphor powder receiving the primary light and radiating a secondary light having a wavelength longer than that of the primary light. An energy of the primary light contained in the radiated secondary light is 0.4 mW/lm or less.

Abstract: In one embodiment, an antibacterial material includes at least one microparticles selected from tungsten oxide microparticles and tungsten oxide complex microparticles. The microparticles, which have undergone a test to evaluate viable cell count by inoculating in a test piece, to which the microparticles are adhered in a range of 0.02 mg/cm? or more and 40 mg/cm? or less, at least one bacterium selected from among Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and enterohemorrhagic Escherichia coli, and storing for 24 hours, have an antibacterial activity value R of 0.1 or more expressed by the following: R=log(B1/C1) where, B1 denotes an average value (number) of viable cell count after storing an untreated test piece for 24 hours, and C1 denotes an average value (number) of viable cell count after storing the test piece on which the microparticles are coated for 24 hours.

Abstract: According to one embodiment, there is provided a white light source system including white light sources. An absolute value of a difference between (P(?)×V(?))/(P(?max1)×V(?max1)) and (B(?)×V(?))/(B(?max2)×V(?max2)) for each of the white light sources satisfies a relational expression represented by |((P(?)×V(?))/(P(?max1)×V(?max1))?(B(?)×V(?))/(B(?max2)×V(?max2))|?0.15 The white light source system has a light emission characteristic of white light emitted by the system is continuously changed along with an elapse of time by changing a mixing ratio of light beams from the white light sources.

Abstract: According to one embodiment, an illumination system includes a plurality of white light sources that satisfies ?0.2?[(P(?)×V(?))/(P(? max 1)×V(? max 1))?(B(?)×V(?))/(B(? max 2)×V(? max 2))]?+0.2 where P(?) is an emission spectrum of a white light source having a specific color temperature, B(?) is an emission spectrum of black body radiation having a corresponding color temperature, V(?) is a spectrum of spectral luminous efficiency, ? max 1 is a wavelength at which P(?)×V(?) becomes maximum, and ? max 2 is a wavelength at which B(?)×V(?) becomes maximum. The respective white light sources have different color temperatures, and light from the respective white light sources is irradiated from different directions to a target.

Abstract: A phosphor according to an embodiment is a europium-activated alkaline-earth chloroapatite phosphor having a composition expressed by a composition formula: (M1-xEux)5(PO4)3Cl, where M is an alkaline-earth element containing at least Sr and Ba, x is an atomic ratio satisfying 0.04?x?0.2. In the phosphor of this embodiment, absorptance of light at a wavelength of 400 nm is 90% or more, and absorptance of light at a wavelength of 650 nm is 2% or less.

Abstract: A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.

Abstract: A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.

Abstract: According to one embodiment, there is provided a white light source system including white light sources. An absolute value of a difference between (P(?)×V(?))/(P(?max1)×V(?max1)) and (B(?)×V(?))/(B(?max2)×V(?max2)) for each of the white light sources satisfies a relational expression represented by |((P(?)×V(?))/(P(?max1)×V(?max1))?(B(?)×V(?))/(B(?max2)×V(?max2))|?0.15 The white light source system has a light emission characteristic of white light emitted by the system is continuously changed along with an elapse of time by changing a mixing ratio of light beams from the white light sources.

Abstract: A phosphor has a composition represented by Chemical formula 1: 1.5Y2O3.2.5aAl2O3:Ce where a is a number satisfying 1.02<a<1.1.

Abstract: A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.

Abstract: According to one embodiment, an illumination system includes a plurality of white light sources that satisfies ?0.2?[(P(?)×V(?))/(P(?max1)×V(?max1))?(B(?)×V(?))/(B(?max2)×V(?max2))]?+0.2 where P(?) is an emission spectrum of a white light source having a specific color temperature, B(?) is an emission spectrum of black body radiation having a corresponding color temperature, V(?) is a spectrum of spectral luminous efficiency, ?max1 is a wavelength at which P(?)×V(?) becomes maximum, and ?max2 is a wavelength at which B(?)×V(?) becomes maximum. The respective white light sources have different color temperatures, and light from the respective white light sources is irradiated from different directions to a target.

Abstract: A visible-light-responsive photocatalyst powder includes a tungsten oxide powder. The tungsten oxide powder has color whose a* is ?5 or less, b* is ?5 or more, and L* is 50 or more when the color of the powder is expressed by an L*a*b* color system. Further, the tungsten oxide powder has a BET specific surface area in a range of 11 to 820 m2/g.

Abstract: An LED light emitting device is provided that has high color rendering properties and is excellent color uniformity and, at the same time, can realize even luminescence unattainable by conventional techniques. A phosphor having a composition represented by formula: (Sr2-X-Y-Z-?BaXMgYMnZEu?)SiO4 wherein x, y, z, and ? are respectively coefficients satisfying 0.1<x<1, 0<y<0.5, 0<z<0.1, y>z, and 0.01<?<0.2 is provided. The phosphor is used in combination with ultraviolet and blue light emitting diodes having a luminescence peak wavelength of 360 to 470 nm to form an LED light emitting device.

Abstract: The present invention provides a white light source comprising a light emitting diode having a light emission peak wavelength of 350 to 490 nm and a phosphor that emits visible light upon excitation by a light emitted from the light emitting diode; wherein, with respect to an arbitrary local maximum value of light-emission intensity between 350 and 780 nm of a light emission spectrum of the white light source, a ratio of a local minimum value of light-emission intensity that is closest on a long wavelength side to the local maximum value is such that, when the local maximum value is taken as 1, the local minimum value is 0.5 or more.

Abstract: A visible-light-responsive photocatalyst powder includes a tungsten oxide powder. When the tungsten oxide powder is measured by X-ray diffractometry, (1) among intensity ratios of a peak A (2?=22.8 to 23.4°), a peak B (2?=23.4 to 23.8°), a peak C (2?=24.0 to 24.25°), and a peak D (2?=24.25 to 24.5°), an A/D ratio and a B/D ratio each fall within a range of 0.5 to 2.0, and a C/D ratio falls within a range of 0.04 to 2.5, (2) an intensity ratio (E/F) of a peak E (2?=33.85 to 34.05°) to a peak F (2?=34.05 to 34.25°) falls within a range of 0.1 to 2.0, and (3) an intensity ratio (G/H) of a peak G (2?=49.1 to 49.7°) to a peak H (2?=49.7 to 50.3°) falls within a range of 0.04 to 2.0, and the tungsten oxide powder has a BET specific surface area in a range of 1.5 to 820 m2/g.

Abstract: A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.

Abstract: The present invention provides a white light source comprising: a blue light emitting diode (blue LED) having a light emission peak wavelength in a range of 421 to 490 nm; and a phosphor layer including phosphor and resin, wherein the white light source satisfies a relational equation of ?0.2?[(P(?)×V(?))/(P(?max1)×V(?max1))?(B?)×V(?))/(B(?max2)×V(?max2))]?+0.2, assuming that: a light emission spectrum of the white light source is P(?); a light emission spectrum of black-body radiation having a same color temperature as that of the white light source is B(?); a spectrum of a spectral luminous efficiency is V(?); a wavelength at which P(?)×V(?) becomes largest is ?max1; and a wavelength at which B(?)×V(?) becomes largest is ?max2, and wherein an amount of chromaticity change on CIE chromaticity diagram from a time of initial lighting up of the white light source to a time after the white light source is continuously lighted up for 6000 hours is less than 0.010.