Patent ID: 8169131

Claim:
A fluorescent material comprising a first phosphor that at least partially converts energy emitted by an excitation source to a first emission spectrum that is different from the energy, and a second phosphor that at least partially converts the first emission spectrum to a second emission spectrum that is different from the first emission spectrum, wherein the first phosphor is a light-storing phosphor, which is represented by the general formula: (Sr 1-a-b Eu a Q b )O. n (Al 2 O 3 ) wherein Q is at least one type selected from the group consisting of Pr, Nd, Dy, Er and Ho; and a is a number that satisfies 0.0001≦a≦0.5; b is a number that satisfies 0.0001≦b≦0.5, and n is a number that satisfies 0.5≦n≦3, a peak wavelength of the emission spectrum of the first phosphor and a peak wavelength of the emission spectrum of the second phosphor have a relation of complementary colors so that when the light created due to the peak wavelength of the first phosphor and the light created due to the peak wavelength of the second phosphor are mixed, the resulting light is in the white region.