Display apparatus with scanning backlight

Display apparatus comprising an image-generating screen repetitively scanned at a predetermined rate to display images, and a backlight for illuminating the screen, the backlight including:

• at least one light source;
• a light guide arranged to constrain light derived from said at least one source by total internal reflection, the light guide having an output surface with various locations from which light may be selectively coupled;
• and
• scanning means configured to selectively couple light from said various locations on the output surface of said light guide to sequentially and repeatedly illuminate selected areas of said screen in synchronism with the repetitive scanning of said screen.