THREE DIMENSIONAL DISPLAYS

摘要

A 3D projection display system uses a holographic arrangement to produce a three dimensional real image of a CAD solid model displayed on a CAD workstation (1) in a scattering medium (2). Successive cross-sectional level slice images through the CAD solid model are displayed as holograms on a liquid crystal spatial light modulator (3), which is illuminated with a coherent read-out beam from a laser diode source (4) to "read-out" the holograms as they are displayed such that the corresponding cross-sectional image is reconstructed at the desired z-axis position within the scattering medium (2). To achieve the necessary complex encoding of the holograms to be displayed on the spatial light modulator (3), the pixels of the spatial light modulator (3) are arranged in pairs as "macropixels", with one pixel of each pair being used to represent the real component of the complex wavefront at that particular pixel location, and the second pixel of each pair being used to represent the imaginary component of the wavefront at that pixel location. The display of the cross-sections on the spatial light modulator (3) is time multiplexed and repeated in an appropriate manner to allow persistence of vision to give the illusion of a full three dimensional image in the scattering medium (2).