METHOD FOR COMPENSATING FOR OPTICAL ABERRATIONS BY MEANS OF TN-LCD-TYPE LIQUID CRYSTAL SCREENS, AND DEVICE FOR IMPLEMENTING SAME

摘要

The method consists in causing the beam (2) whose aberration is to be compensated for to impact upon a TN-LCD screen (1), applying, to each pixel of the screen, the appropriate voltage level for modifying the birefringence thereof, such that a change in the polarization state of the incident wave is induced. The aberration is compensated for in two steps: static compensation equal to the mean temporal value of the aberration of the wavefront to be corrected; and time-dependent dynamic compensation of the residual aberration that persists in the wavefront after the aforementioned static compensation has been completed. The device comprises a dynamic-compensation submodule consisting of a TN-LCD liquid crystal screen (1) placed between a pair of retardation plates (4-5) and two linear polarizers (3-6) and a submodule consisting of an optional optical element (8), which may be static or dynamic, of refractive, diffractive or hybrid type, which are coupled together.