According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

In a phosphor according to an aspect, an emission site has a perovskite crystal structure expressed by ABX.sub.3, in which A and B are each a cation and X is an anion, and an emission element is located at a B site serving as a body center of the perovskite crystal structure.

Provided is an oxide fluorescent material having a light emission peak in a wavelength range from red light to near-infrared light.

The oxide fluorescent material has a composition including: a first element M.sup.1 being at least one element selected from the group consisting of Li, Na, K, Rb, and Cs; a second element M.sup.2 being at least one element selected from the group consisting of Ca, Sr, Mg, Ba, and Zn; Ge; O (oxygen); and Cr, the composition optionally including: a third element M.sup.3 being at least one element selected from the group consisting of Si, Ti, Zr, Sn, Hf, and Pb; and a fourth element M.sup.4 being at least one element selected from the group consisting of Eu, Ce, Tb, Pr, Nd, Sm, Yb, Ho, Er, Tm, Ni, and Mn. When the molar ratio of Ge, or the total molar ratio of the third element M.sup.3 and Ge in the case of comprising the third element M.sup.3, in 1 mol of the composition of the oxide fluorescent material is 6, the molar ratio of the first element M.sup.1 is 1.5 or more and 2.5 or less, the molar ratio of the second element M.sup.2 is 0.7 or more and 1.3 or less, the molar ratio of the third element M.sup.3 is 0 or more and 0.4 or less, the molar ratio of O (oxygen) is 12.9 or more and 15.1 or less, and the molar ratio of Cr is 0.2 or less. The oxide fluorescent material has a light emission peak wavelength of 700 nm or more and 1,050 nm or less in a light emission spectrum of the oxide fluorescent material.

The present invention discloses one or more compounds that oscillate between a first state and a second state due to absorption of high energy, with the oscillations facilitating prevention of solarization of a glass system for reuse while generating scintillations for determining existence of high radiation energy. The generation of scintillations have a duration that is commensurate with a duration of the irradiation of the glass system, and cease when irradiation is ceased without affecting the glass system.

The present invention discloses one or more compounds that oscillate between a first state and a second state due to absorption of high energy, with the oscillations facilitating prevention of solarization of a glass system for reuse while generating scintillations for determining existence of high radiation energy. The generation of scintillations have a duration that is commensurate with a duration of the irradiation of the glass system, and cease when irradiation is ceased without affecting the glass system.

A phosphor according to an embodiment is a europium-activated alkaline-earth chloroapatite phosphor having a composition expressed by a composition formula: (M.sub.1-xEu.sub.x).sub.5(PO.sub.4).sub.3Cl, where M is an alkaline-earth element containing at least Sr and Ba, x is an atomic ratio satisfying 0.04x0.2. 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.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.

An object of the invention is to provide a blue-green light-emitting phosphor having excellent high-temperature property and excellent light-emitting properties such as brightness and half width. The phosphor is constituted of a plurality of alkaline earth metal elements including a barium element, phosphoric acid and a halogen element, and Eu as an activator, in which the molar ratio of the barium element to the total content of the alkaline earth metal elements is larger than 60% and smaller than 95%, and upon irradiation with a near-ultraviolet ray, the blue-green light-emitting phosphor is excited to thereby emit blue-green visible light.