Display device having output directivity control, and backlight and light directing method for such display device

摘要

The display backlight includes an edge illuminated lightguide having an array of light extraction structures that allows light to exit the lightguide at the location of the light extraction structures. The light source device is used to provide light to the light guide at one or both of the opposing side edges. The light source device is controllable to supply at least a selected one of the first and second light outputs to the light guide, the two light outputs being in the overall plane of the light guide. It produces light that exits the light guide with different angles to the exit angle in different ranges. In this way, directional backlight output is possible based on the manner in which light is coupled to the light guide. This provides a simple structure that only requires control of the light supplied to the light guide. The backlight allows, for example, an autostereoscopic display to be formed without the need for a lenticular array.