Illumination system for reproducing the color temperature range of solar light for illuminating exhibits

An illumination system for illuminating a target, comprising:

• at least a first light source and a second light source,
• wherein the first light source and the second light source are configured so that a light component included in a luminous flux from the first light source and a corresponding light component included in a luminous flux from the second light source form different angles in a specific region on a surface of the target,
• emission spectra P1(λ) and P2(λ) of each of the first light source and the second light source have different color temperatures and satisfy conditions of the following Equations, respectively,
• −0.2≤[(P1(λ)×V(λ))/(P1(λ max 1)×V(λ max 1))−(B1(λ)×V(λ))/(B1(λ max 2)×V(λ max 2))]≤+0.2
• −0.2[(P2(λ)×V(λ))/(P2(λ max 1)×V(λ max 1))−(B2(λ)×V(λ)/(B2(λ max 2)×V(λ max 2))]≤+0.2,
• wherein B1(λ) and B2(λ) are emission spectra of black body radiation showing the same color temperatures as those of the first light source and the second light source, respectively, and V(λ) is a spectrum of spectral luminous efficiency, and
• λ is a wavelength, λmax 1 is a wavelength at which P1(λ)× V(λ) or P2(λ)× V(λ) becomes maximum, and λ max 2 is a wavelength at which B1(λ)× V(λ) or B2(λ)× V(λ) becomes maximum.

An illumination method for illuminating a target,

• wherein a first light source and a second light source are arranged so that a light component included in a luminous flux from the first light source and a corresponding light component included in a luminous flux from the second light source form different angles in a specific region on a surface of the target,
• emission spectra P1(λ) and P2(λ) of each of the first light source and the second light source have different color temperatures and satisfy conditions of the following Equations, respectively,
• −0.2≤[(P1(λ)×V(λ))/(P1(λ max 1)×V(λ max 1))−(B1(λ)×V(λ))/(B1(λ max 2)×V(λ max 2))]≤+0.2
• −0.2≤[(P2(λ)×V(λ))/(P2(λ max 1)×V(λ max 1))−(B2(λ)×V(λ))/(B2(λ max 2)×V(λ max 2))]≤+0.2,
• wherein B1(λ) and P2(λ) are emission spectra of black body radiation showing the same color temperatures as those of the first light source and the second light source, respectively, and V(λ) is a spectrum of spectral luminous efficiency, and
• λ is a wavelength, Δmax 1 is a wavelength at which P1(λ)× V(λ) or P2(λ)× V(λ) becomes maximum, and λ max 2 is a wavelength at which B1(λ)× V(λ) or B2(λ)× V(λ) becomes maximum.