© 2019 IEEE. We obtain theoretical expressions and experimental data on various dependences of the perceived depth in an arc 3D display and find that the theoretical and experiment values coincide with each other. We devise two on/off switching methods for an arc 3D display that use liquid-crystal devices and clarify the on/off characteristics. The perceived depth in the arc 3D display increases as the arc radius increases or the lighting angle decreases. The perceived depth keeps its value even when the observer's position changes horizontally, resulting in continuous motion parallax. Moreover, we develop two liquid-crystal active devices that can switch the arc 3D image on or off by changing either the high applied voltage or the frequency of the applied voltage.