DISPLAY SYSTEM UTILIZING AMBIENT LIGHT AND A DEDICATED LIGHT SOURCE

摘要

A display system (20) generally comprising a display device (28) operable to display an image and configured for illumination by ambient light or light emitted by a dedicated light source (22) and a light directing system. The light directing system is operable to direct one of the ambient light and the light emitted by the light source towards the display device. The light directing system comprises at least one holographic optical element (34) which is switchable between an active state wherein light incident on the element is diffracted and a passive state wherein light incident on the element is transmitted without substantial alteration.