| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light-emitting device with high luminous efficacy. <P>SOLUTION: A light-emitting device comprises: first luminous bodies 7 and 22; and second luminous bodies 8 and 23 that emit visible light by light irradiation from the first luminous bodies. The light-emitting device includes a first fluorescent substance and a second fluorescent substance as the second luminous body. In a chromaticity coordinate of an emission spectrum of the light-emitting device, x of a CIE coordinate is 0.285 or less, and y is 0.300 or less. The light-emitting device includes as the first fluorescent substance a β-type sialon phosphor whose mass median diameter D<SB POS="POST">50</SB>is not less than 8 μm nor more than 25 μm, and includes as the second fluorescent substance a phosphor whose mass median diameter D<SB POS="POST">50</SB>is not less than 8 μm nor more than 15 μm, and having an excitation band in a wavelength range of not less than 500 nm nor more than 560 nm. The mass median diameter D<SB POS="POST">50</SB>of the first fluorescent substance is equal to the mass median diameter D<SB POS="POST">50</SB>of the second fluorescent substance, or is greater than the mass median diameter D<SB POS="POST">50</SB>of the second fluorescent substance. <P>COPYRIGHT: (C)2013,JPO&INPIT |
