Light source driving device

A light source driving device, comprising:

• a storage unit that stores therein three or more combinations of a level indicating brightness of light emitted from a light source, and a control value used when light with brightness corresponding to the level is emitted from the light source, the control value having a nonlinear relation with the level;
• and
• a control unit that controls the light source so that the brightness of the light emitted from the light source is gradually changed to brightness corresponding to a target level indicated by a light control instruction signal during the first time period, by calculating an intermediate level indicating the brightness of the light emitted from the light source between an initial level when a light control instruction signal is supplied and the target level indicated by the light control instruction signal, at each second time period that is shorter than the first time period, by specifying two adjacent levels among the combinations stored in the storage unit, adjacent to the calculated intermediate level, for calculating the control value corresponding to the intermediate level,
• wherein the first time period is a time period in which the brightness of the emitted light has been changed to the target level,
• the first time period comprises two or more successive second time periods, and
• the two adjacent levels adjacent to the intermediate level include a greater level greater than the intermediate level and a smaller level smaller than the intermediate level.