Three dimensional projection display

• Main Authors: CHRISTOPHER REGINALD CHATWIN, RUPERT CHARLES DAVID YOUNG
• Format: Patent
• Language: English
• Published: 07.12.2005
• Edition: 7
• Subjects: CINEMATOGRAPHY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHIC PROCESSES OR APPARATUS; HOLOGRAPHY; PHOTOGRAPHY; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION

A method of generating a 3D image, preferably colour and user controllable, from a 3D CAD model, or another object, comprises the following steps: dividing the object into sequential cross-sectional slices; determining a near field hologram for each slice, calculated as Fresnel transform; displaying each transform, preferably more than one simultaneously, on an SLM 3, and; illuminating the SLM 3, preferably with laser source 4, to project a 3D image for display. Display and illumination of each transform is repeated to create a persistence of vision effect. The image displayed is preferably reconstructed in a holographic medium 2, (fig. 3, 30), from which images may be recorded when it is illuminated by the laser source 4, (fig. 3, 4). Recorded images can be displayed in the medium (fig. 3, 30) using a light source (fig. 3, 31). The SLM 3 is composed of pixels pairs, the real and imaginary components of each transform being displayed on respective pixels of each pair. A f /2 relative phase shift between real and imaginary components may be achieved using a phase detour technique. Preferably, a step of multiplying the data on every second real and imaginary pixel pair by -1 is included. A number of independent claims are included.