Adaptive Shell Spherical Reflector Actuated with PVDF-TrFE Thin Film Strain Actuators

This paper discusses the design and manufacturing of a thin polymer spherical adaptive reflector of diameter D=200 mm, controlled by an array of 25 independent electrodes arranged in a keystone configuration actuating a thin film of PVDF-TrFE in d31-mode. The 5 mu m layer of electrostrictive material is spray-coated. The results of the present study confirm that the active material can be modelled by a unidirectional quadratic model and that excellent properties can be achieved if the material is properly annealed. The experimental influence functions of the control electrodes are determined by a quasi-static harmonic technique; they are in good agreement with the numerical simulations and their better circular symmetry indicates a clear improvement in the manufacturing process, as compared to a previous study. The low order optical modes can be reconstructed by combining the 25 influence functions; a regularization technique is used to alleviate the ill-conditioning of the Jacobian and allow to approximate the optical modes with reasonable voltages.

Automated summary

This paper discusses the design and manufacturing of a thin polymer spherical adaptive reflector controlled by 25 independent electrodes. Experimental influence functions of control electrodes were determined, showing an improvement in manufacturing process and the ability to approximate optical modes with reasonable voltages. The study confirms that the active material can be modeled by a quadratic model and achieve excellent properties with proper annealing.