Patent ID: 7898664

Claim:
A method for measuring chromaticity values in a colorimeter, comprising: (a) emitting three visible band light of different spectra, S(λ)* x (λ)/PM(λ), S(λ)* y (λ)/PM(λ) and S(λ)* z (λ)/PM(λ) individually on a surface of an object with a multi-band illuminant, wherein the multi-band illuminant comprises a plurality of color light emitting diodes (LEDs) to form the spectra, S(λ)* x (λ)/PM(λ), S(λ)* y (λ)/PM(λ) and S(λ)* z (λ)/PM(λ) individually based on a requested S(λ) of a certain color temperature; (b) receiving reflective lights reflected off the surface of the object with a power meter, wherein the power meter is calibrated to perform the function of 683*∫PM(λ)dλ, wherein the reflective lights are with spectra of R(λ)*[S(λ)* x (λ)/PM(λ)], R(λ)*[S(λ)* y (λ)]/PM(λ)] and R(λ)*[S(λ)* z (λ)/PM(λ)]; (c) computing chromaticity values X, Y, Z of the object based upon a luminous intensity received by the power meter, wherein the power meter receives the reflective lights reflected off the surface of the object; and (d) obtaining the chromaticity values X, Y, Z that is X = 683 * ∫ S ⁡ ( λ ) ⁢ x _ ⁡ ( λ ) PM ⁡ ( λ ) ⁢ R ⁡ ( λ ) ⁢ PM ⁡ ( λ ) ⁢ ⅆ λ Y = 683 * ∫ S ⁡ ( λ ) ⁢ y _ ⁡ ( λ ) PM ⁡ ( λ ) ⁢ R ⁡ ( λ ) ⁢ PM ⁡ ( λ ) ⁢ ⅆ λ Z = 683 * ∫ S ⁡ ( λ ) ⁢ z _ ⁡ ( λ ) PM ⁡ ( λ ) ⁢ R ⁡ ( λ ) ⁢ PM ⁡ ( λ ) ⁢ ⅆ λ , wherein an illuminating spectrum tunes the effect of S(λ) based upon various requested colorimetric conditions, wherein the various requested colorimetric conditions are CIE standard illuminants A and C.