A system and method corrects luminance non-uniformity caused by images being obliquely projected onto a screen. The phosphor is excited by vacuum ultraviolet radiation and may be used to create a mercury-free germicidal lamp. A skirt centrally and downward extends from a bottom of the cover to define a cavity for receiving a battery. Movement of the camming mechanism results in movement of a drawer with respect to the drawer slide during installation. Some action is taken relative to the actions that are likely to occur, before those actions actually happen.