Patent ID: 8063584

Claim:
A light output device comprising: an output unit configured to output light from a light source; a feedback-signal generating unit configured to generate a feedback control signal for maintaining output power of the light at a predetermined value, wherein the feedback-signal generating unit is further configured to generate the feedback control signal in a gradually rising manner and to supply the generated feedback control signal to the output unit so that output power of the light is gradually increased at a time of power-on; a controller configured to set the predetermined value of the output power and to control output of the output unit; a discharge circuit configured to discharge a charge stored in the feedback-signal generating unit and to accelerate decrease of the feedback control signal; and a power-voltage monitoring circuit configured to monitor a voltage of the power supplied to the output unit and to detect at least one of shutdown and return of the power, wherein the power-voltage monitoring circuit is further configured to, upon detecting shutdown of the power, controls the discharge circuit and cause discharge of the charge stored in the feedback-signal generating unit.