Luminance control apparatus and luminance control method

A luminance control device for controlling luminance of a light emitting member by varying a duty ratio of a pulse current or a pulse voltage for driving the light emitting member in each of a plurality of unit periods into which a luminance transition period is equally divided, the luminance control device comprising:

• a duty ratio storage unit for storing a reference duty ratio in each of the plurality of unit periods;
• a division number storage unit for storing an interpolation division number;
• a calculation unit for calculating an interpolation variation width in one unit period by dividing by the interpolation division number a value obtained subtracting the reference duty ratio in the one unit period from the reference duty ratio in the next unit period among the plurality of unit periods;
• an integration unit for integrating the interpolation variation width into the reference duty ratio in the unit period every time an interpolation period elapses, the interpolation period in which the unit period is equally divided by the interpolation division number in each of the plurality of unit periods;
• and
• a control unit for causing the light emitting member to emit light at the duty ratio determined by the integrating unit.