Projection display using computer-generated phase screens
N. Collings · SPIE Newsroom · 2008
An approach to a robust and efficient projection display uses phase-modulating screens that reduce computer overhead. The first device based on a phase screen for projection display was the Eidophor system, initially developed in the 1940s.1 An oil film is deformed by a cathode ray beam to produce the phase profile, while a so-called Schlieren system is used to convert the phase image into an amplitude image. Schlieren optics result in light loss because the light diffracted from the beam path is de-posited on the bars of a mirror bar system. In a more efficient phase structure, light is redirected from the dark to the illumi-nated parts of the image. Today, more complex phase screens than the ones used in the Eidophor system perform this opera-tion. At a meeting with contractors in December 2000, two of us (NC and BC) raised the prospect of using phase-modulating