The frame is collapsible longitudinally to the extension of the stroller to change from an open position to a folded position and the handlebar has arms engaging in a sliding manner in corresponding seats in the frame to enable traversing downward thereof upon folding of the frame towards the folded position so as to move from a use position to a retracted position. The parallax information generating section corrects the parallax information based on the reliability information. The output signal is controlled by a control circuit that sets up a control loop between the drop in the gate voltage level of the switching transistor and the voltage level of the output line that is controlled by the switching circuit. The one or more light modulating chips are operable to receive the one or more optical signals and to modulate the one or more optical signals based at least in part on the control signal.