Patent ID: 7954967

Claim:
A directional backlight comprising: a surface light source having a characteristic that luminance distribution of light rays emitted from a light-emitting surface of the surface light source are concentrated close to the normal direction of the light-emitting surface; a polarizing device unit that includes a first transparent substrate that faces the light emitting surface of the surface light source, a second transparent substrate that faces the first transparent substrate, a pair of electrodes that are formed between the first transparent substrate and the second transparent substrate, the electrodes having wiring patterns arranged in stripes, a liquid crystal layer retained between the electrodes, and a light-shielding layer that is provided on the second transparent substrate and has a plurality of openings corresponding to the wiring patterns of the electrodes, wherein the openings defined in the light-shielding layer are smaller in size than sub-pixels that form a display pixel of a liquid-crystal display device that faces the polarizing device unit; and a voltage controller that switches a voltage application state of the wiring patterns of the electrodes among a plurality of voltage application states and individually controls values of voltages to be applied to the wiring patterns in the voltage applications states, thereby controlling a direction of light rays emitted from the surface light source and passing through the openings toward a predetermined position.