Importance

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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(λ)×V(λ))/(P(λmax1)×V(λmax1))−(Bλ)×V(λ))/(B(λmax2)×V(λmax2))]≦+0.2, assuming that: a light emission spectrum of the white light source is P(λ); a light emission spectrum of black-body radiation having a same color temperature as that of the white light source is B(λ); a spectrum of a spectral luminous efficiency is V(λ); a wavelength at which P(λ)×V(λ) becomes largest is λmax1; and a wavelength at which B(λ)×V(λ) becomes largest is λmax2, 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. According to the above white light source, there can be provided a white light source capable of reproducing the same light emission spectrum as that of natural light.

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First Claim