Projection system, light beam generating device thereof and method for controlling light beam luminance

A projection system, comprising:

• a lens;
• and
• a light beam generating device, coupled to the lens comprising:
• a first controller;
• a driver, coupled to the first controller and adapted to generate a driving current according to a control command;
• a illuminating device, coupled to the driver and adapted to generate an output light beam according to the driving current;
• a sensing device, coupled to the driver and the illuminating device and adapted to detect the driving current and the output light beam, so as to respectively generate a sensing current signal and a sensing luminance signal;
• and
• a second controller, coupled to the first controller, the sensing device and the driver and adapted to generate an adjustment signal according to the sensing current signal and the sensing luminance signal,
• wherein the first controller or the second controller is adapted to generate the control command according to the adjustment signal, and a computing speed of the second controller is greater than a computing speed of the first controller.

A method for controlling light beam luminance, comprising:

• by a driver, generating a driving current according to a control command;
• by an illuminating device, generating an output light beam according to the driving current;
• by a sensing device, detecting the driving current and the output light beam, so as to respectively generate a sensing current signal and a sensing luminance signal;
• by a first controller or a second controller, generating the control command according to the adjustment signal;
• and
• by a second controller, generating the adjustment signal according to the sensing current signal and the sensing luminance signal,
• wherein a computing speed of the second controller is greater than a computing speed of the first controller.