Deformable mirror reduces speckle

Projection-display manufacturers are increasingly motivated to use brighter, more energy-efficient, and broader color-space laser illumination in applications ranging from digital cinema to mobile phones.

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Projection-display manufacturers are increasingly motivated to use brighter, more energy-efficient, and broader color-space laser illumination in applications ranging from digital cinema to mobile phones. One problem that must be addressed is the artifact of speckle—bright and dark spots that arise in the image due to constructive and destructive interference in the coherent beam.

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To reduce laser speckle, Dyoptyka (Dublin, Ireland) announced a “dynamic optics” solution that is an evolution of classical adaptive optics. Its deformable mirror is used in an open-loop configuration to rapidly change the phase and coherence of the illumination laser beam. This approach is similar to the more common, but less effective and practical to integrate, mechanically actuated diffuser approach: to generate a sequence of minimally correlated speckle patterns that vary so rapidly that the human eye sees only an average pattern without speckle. Dyoptyka’s approach reduces the speckle contrast ratio to a level of less than 1%—far below the typical 5% sought by many projector manufacturers. With a medium-term volume price target of $10 per optic, Dyoptyka currently supplies 1- and 3-in.-diameter evaluation kits as part of its technology evaluation program. Contact Fergal Shevlin at fshevlin@dyoptyka.com.

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