Emission currents in piezoelectric (PZ) transducers used in optoelectronic processing systems are considered. Charge carrier injection in dielectrics from metal electrodes lead to uneven polarization, piezoand electrooptical properties distributions across thickness of thin layer MDM structures. Theory of these combined PZ and elastic-optical effects in ferroelectric PLZT-type ceramics is given. Mechanical stressstrain state and electromechanical flextensional effect in homogeneous PZ layer used in spatial light modulator are investigated in detail.