Speckle reduction apparatus for laser image projections

摘要

The apparatus includes an ultra sound source which is used to divide the illumination beam of a projector in different diffraction orders with different frequencies. After superimposition of the beam components, a running, locally deep modulated interference strip system on the projection screen. The interference strip system illuminates within an illuminated pixel on the screen different locations. Temporally variable different speckle patterns are formed which are superimposed in the eye of the observer and the speckle effect can be reduced by appropriate temporal averaging.