Abstract: A light emitting apparatus has light emitting units. The light emitting units can be respectively provided with current densities, so that the light emitted by each of the light emitting unit has a light intensity, wherein the current densities are different from each other, or partial of the current densities are different from each other. A number of the light emitting units can be larger than or equal to four, all of the four lighting frequencies of the four light emitting units are different from each other, or partial of the four lighting frequencies of the four light emitting units are identical to each other, and the light emitting apparatus and the object under test rotate relative to each other. A light emitting method, a spectrum detection method and a lighting correction method are also illustrated for increasing SNR, correcting the light intensity or the spectrum signal.

Abstract: An optical analysis system and an optical analysis method, which simply change driving electric currents of light-emitting units via using a control and process unit, so that a wavelength range and a peak wavelength of an irradiated light generated by each light-emitting unit may be fine-tuned. A plurality of irradiating lights with different wavelength ranges and peak wavelengths are irradiated to the object to be tested in different times, so that merely fewer light-emitting units may be used to improve a detection resolution and a detection accuracy of a spectrum of the object to be tested.