screen backlight, auto stereoscopic display device or privacy screen, method for controlling the direction of a backlight output, and method for controlling an auto stereoscopic display device

摘要

The present invention relates to a screen backlight comprising an edge lit light guide having an array of outer light coupling structures to enable light to escape from the light guide at the location of the outer coupling structures. of light. a light source arrangement is used to provide light in the light guide at one or both opposite side edges; The light source arrangement is controllable to provide an output selected from at least the first and second light outputs in the light guide, the two different light outputs having a different angle to the overall light guide plane. and results in light escaping the light guide with a different range of exit angles. In this way, a directional backlight output is enabled based on the way the light is coupled to the light guide. This provides a simple structure that only requires control of the light provided to the light guide. Backlighting can, for example, enable a self-stereoscopic screen to be formed without the need for a lenticular matrix.