Light scanning unit and method of detecting scanning synchronization signal

A light scanning unit, comprising:

• a light source configured to produce light;
• a deflection mirror having a reflective surface, the deflection mirror being positioned such that the light produced by the light source is incident upon the reflective surface;
• a driver having an input through which to receive a driving current, the driver being configured, in response to the received driving current, to drive the deflection mirror to oscillate such that the light incident upon the reflective surface of the deflection mirror is deflected bidirectionally across a scanned range;
• a detection mirror disposed in proximity to a first end of the scanned range, the detection mirror being configured to receive the deflected light from the deflection mirror and to reflect the received deflected light toward a second end opposite the first end of the scanned range;
• a photo-sensor disposed in proximity to the second end of the scanning range, the photo-sensor being configured to output a detection signal in response to receiving each of the deflected light from the deflection mirror and the reflected light from the detection mirror;
• and
• a controller configured to synchronize a scanning operation based on the detection signal and an information associated with the driving current.