Reference light source device used for calibration of spectral luminance meter and calibration method using same

A method of calibrating a spectral radiance meter using an integrating sphere having a radiance reference plane, which is an opening;

• and also using a plurality of first optical ports, which are formed apart from each other in an outer wall of the integrating sphere to allow light rays with equivalent wavelength characteristics to enter an interior of the integrating sphere, the method comprising the steps of:
• supplying a light ray using a single light source, to each of the plurality of first optical ports through an optical fiber,
• measuring a radiance of the radiance reference plane with a spectral radiance meter to be calibrated;
• measuring an irradiance of the radiance reference plane with a calibrated spectral irradiance meter;
• and
• calibrating the spectral radiance meter to be calibrated based on the measured radiance, the measured irradiance, and a relationship between the radiance and the irradiance,
• wherein the light rays emitted from the plurality of first optical ports overlap each other on the radiance reference plane,
• wherein the plurality of first optical ports include one first optical port and another first optical port,
• wherein the positions of the one first optical port and the another first optical port are equidistant from the center of the radiance reference plane and have 2-fold symmetry or 3-fold symmetry with respect to a rotational symmetry axis R,
• wherein the radiance reference plane is formed by a circular opening at a center of the integrating sphere;
• and
• a light ray emitted from the one first optical port and a light ray emitted from the another first optical port are irradiated on the radiance reference plane at a same time.