Patent ID: 8259243

Claim:
Controllable device for phase modulation of coherent light with a spatial light modulator which comprises a modulator matrix with a regular arrangement of controllable liquid crystal modulator cells, with at least one light source which illuminates the modulator matrix, and with a control unit which controls the phase modulation in the liquid crystal modulator cells, for realising a three-dimensional image representation, Where the controllable liquid crystal modulator cells have a layer with the functionality of a controllable λ/2 plate with liquid crystal molecules of the type and arrangement of polarization shielded smectic liquid crystal cells, said layer being disposed between two layers with the functionality of non-controllable λ/4 plates, Where each liquid crystal modulator cell can be controlled locally by the control unit with an individual positive or negative voltage value, depending on the positive or negative sign of a phase value to be written, Where the control unit is programmed such to generate a globally constant phase offset for the phase values to be written to the liquid crystal modulator cells, and Where the globally constant phase offset is generated in every other frame.