Light emission control apparatus and light emission control method with temperature-sensitive driving current control

A light emission control apparatus comprising:

• a temperature-current profile storage unit storing a table mapping the ambient temperatures to tolerable currents showing characteristics of the ambient temperature with respect to the tolerable current of the light emitting element;
• a temperature determining unit determining the ambient temperatures;
• a driving current determining unit determining a command value defining a maximum tolerable current of the light emitting element allowable when the ambient temperature is to be restricted to a predetermined level, by referring to the table mapping the ambient temperatures to the tolerable currents;
• and
• a driving current control unit controlling the driving current to drive the light emitting element in accordance with the command value thus determined.

A light emission control method comprising:

• detecting a forward voltage of a light emitting element;
• determining an ambient temperature of the light emitting element from the detected forward voltage, by referring to a table mapping the forward voltages to the ambient temperatures showing characteristics of the ambient temperature with respect to the forward voltage of a light emitting element;
• and
• determining a feedback point of a driving current to drive the light emitting element in accordance with the ambient temperature thus determined so as to control the driving current to drive the light emitting element accordingly, wherein
• the determining the feedback point of the driving current to drive the light emitting element and controlling the driving current to drive the light emitting element accordingly includes referring to a table mapping the ambient temperatures to tolerable currents showing characteristics of the ambient temperature with respect to the tolerable current of the light emitting element, and wherein
• a maximum tolerable current of the light emitting element allowable when the ambient temperature is to be restricted to a predetermined level is determined by referring to the table mapping the ambient temperatures to the tolerable currents, and the command value defining the driving current is determined in accordance with the maximum tolerable current.