A 3D
display device with controllable device for tracking
visibility regions is disclosed, and includes a controllable device for tracking a
visibility region, generated by way of superposition of
light source images, in a observer plane of the
display device. In preferred embodiments, the cladding of a
waveguide comprises at least one material with optical properties of an anisotropic liquid, or at least two materials with optical properties of an isotropic liquid; a matrix arrangement of control electrodes defines multiple positions to be generated for local exit points in the cladding of the
waveguide at which the total reflection is locally cancelled; and a
system controller modifies positions of the output
coupling points for superposing the output-coupled light through the
lens array to the
visibility region by displacing an output
coupling point, or by switching off one output
coupling point and switching on another one.