According to one embodiment, a backlight device includes a light source, a light guide plate, a light beam controller, and a directivity control element. The system can include an illumination system, the object, spatial light modulators, and a controller. The invention also provides a method for producing the polyolefin graft copolymer. In yet a further embodiment, the door operator is implemented using an alternating current synchronous motor. Other methods, devices andor systems are also disclosed. The upper portion is releasably coupled to the at least one cable such that the upper portion is uncoupled from the at least one cable when the support post is displaced.