| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light-emitting device whose color temperature is variable, and that is capable of downsizing and reducing a color phase irregularity, and to provide a lighting device using the light-emitting device. <P>SOLUTION: A light-emitting device 1 has a LED chip 4 and a wavelength conversion member 6. The wavelength conversion member 6 includes a phosphor 8 which gets excited by a portion of the emitted light from the LED chip 4 to emit a light which has a different wavelength from the light emitted from the LED chip 4. The light-emitting device 1 irradiates a white light which is attained by mixing the emitted light from the LED chip 4 with the light from the phosphor 8. An external quantum efficiency of the phosphor 8 included in the wavelength conversion member 6 has a temperature dependency which decreases in the ranges of 5% or more and 90% or less with respect to a temperature increase of 10°C when the temperature range of the wavelength conversion member 6 is 80°C or more. When a control circuit 10 increases a driving current to the LED chip 4 to raise the temperature of the wavelength conversion member 6, the external quantum efficiency of the phosphor 8 declines and the light emitted from the phosphor 8 decreases, so that the color temperature of the mixed light changes. <P>COPYRIGHT: (C)2012,JPO&INPIT |
