Single and multi-user head tracked glasses-free 3D displays

This paper describes two head tracked displays; both provide glasses-free 3D (autostereoscopic) to viewers by producing pairs of exit pupils where the left and right stereo images are directed to the appropriate viewers´ eyes under the control of a head tracker. The first display is single viewer where exit pupils are formed by a pair of picoprojectors whose position moves in accordance with the viewer´s head position. Light is reflected back to the viewer´s eyes using a retroreflecting screen. The second display is multi-user and is laser-based. A Gabor superlens screen is scanned with a vertical illumination column that acts as the backlight for a direct-view liquid crystal display (LCD). The emergent beam directions are controlled by a spatial light modulator (SLM) such that they land on the viewers´ left and right eyes alternately. For each display the principle of operation, the display hardware and the results are presented here.