This invention is related to an active matrix liquid crystal display or an X-ray imaging device having a high aperture ratio, and method of making same. The methods involve preparing an amine-terminated first prepolymer by reacting isocyanate compound A with a stoichiometric excess of polyamine. Duty cycles of the light sources are a function of the control signal and vary inversely. When a container is locked on for a move, the mobile unit starts reporting positions and velocities to the dispatcher workstation over a radio channel.