Patent ID: 8786916

Claim:
A light-source driving device comprising: driving circuitry configured to drive a light source unit that emits light onto an object; and driving control circuitry configured to receive a first constant amplitude electric-current control signal in a first driving mode and a second constant amplitude electric-current control signal in a second driving mode and to control the driving circuitry to drive the light source unit in the first driving mode and the second driving mode, wherein a light emission time of the light source unit is controlled in the first driving mode, and an instantaneous value of a quantity of light of the light source unit is controlled in the first driving mode and in the second driving mode, and wherein, in the first driving mode, the instantaneous value of the quantity of light of the light source unit is based on the first constant amplitude electric-current control signal, and in the second driving mode, the instantaneous value of the quantity of light of the light source unit is based on the second constant amplitude electric-current control signal.