Laser projection apparatus with liquid-crystal light valves and scanning reading beam

摘要: Laser lines at 635 nm or longer (ideally 647 nm) are preferred for red, giving energy-efficient, bright, rapid-motion images with rich, full film-comparable colors. Green and blue used too—and cyan retained best color mixing, an extra light-power boost, aid in speckle suppression. Speckle is suppressed through beam-path displacement—by deflecting the beam during projection, thereby avoiding both absorption diffusion of while preserving pseudocollimation (noncrossing rays). The latter turn important to infinite sharpness. Path displacement achieved by scanning on liquid-crystal valves (LCLVs), which also provides several enhancements—in energy efficiency, brightness, contrast, uniformity (by suppressing laser-mode ripple artifacts), convenient beam-turning transfer between apparatus tiers. Preferably deflection performed a mirror mounted galvanometer motor rotary oscillation; written incrementally successive portions LCLV control stage (either optical electronic) laser “reading beam” synchronized output stage. shaped, very little loss masking, into shallow cross-section shifted viewing screen as well LCLVs. Beam-splitter/analyzer cubes over polarizing sheets. Spatial modulation provided maintained enables imaging irregular projection media distinctly differing distances from projector—including domes, sculptures, monuments, buildings; waterfalls, sprays, fog, clouds, ice; scrims other structures; trees foliage; land rock surfaces; even assemblages living creatures including people.