Auto-stereoscopic 3D Display Designs
Auto-stereosocpic 3D displays guide the left and right views to each eye without the need for the viewer to wear glasses or other devices. There are a number of competing optical technologies that achieve this effect and three of the most important design approaches are summarised below.
Two-View Auto-stereoscopic Displays.
Two view displays generate the two views for the left and right eyes in two viewing windows in space. These are primarily visible from a central viewing position and the user may have up to 20 or 30 mm of movement around the central viewing position before they loose the 3D effect.
Typically this type of display has high resolution per view and low cost. Some displays allow switching the display between 3D and 2D allowing the display to function as a standard monitor when the 3D effect is not required.
Multi-View Auto-stereoscopic Displays.
Multi-view displays provide more than two views simultaneously in multiple viewing windows, for example there may be eight or nine views. The viewer sees any two of these simultaneously and the views are arranged so that each simultaneously visible pair forms a valid stereo image. The key benefit of these displays is the wider lateral viewing freedom this allows. They can also allow multiple simultaneous viewers.
Typically modern displays of this type have low resolution per view as the underlying display must be divided into multiple views but they benefit from relatively low cost. Multi-view displays rarely allow 2D/3D switching.
Tracking Two View Auto-stereoscopic Displays.
Tracking two-view displays aim to provide the higher resolution per view of two-view displays and the wide viewing freedom of multi-view displays. They achieve this by generating just two views and steering these to follow the viewers head position. This requires a viewing window steering mechanism in the display and a head tracking mechanism linked to it to detect where the viewer is.
These displays provide high resolution per view and wide viewing freedom but at the cost of requiring tracking and steering mechanisms, Currently these displays will not normally have 2D/3D switching ability.