Backlight modules for autostereoscopic 3d display devices and scanning backlights for lcd devices

A scanning backlight for a stereoscopic 3D liquid crystal display apparatus includes a light guide having a first side and a second side opposite the first side, and having a first surface extending between the first and second sides and a second surface opposite the first surface. The first surface substantially re-directs light and the second surface substantially transmits light. A plurality of first light sources are arranged along the first side of the light guide for transmitting light into the light guide from the first side and a plurality of second light sources are arranged along the second side of the light guide for transmitting light into the light guide from the second side. The first light sources are divided into a plurality of first groups and the second light sources are divided into a plurality of second groups, each first group having a corresponding and opposing second group, and the first groups and second groups are selectively turned on and off in a particular pattern where only the fi