Movable optical lens array using ultrasonic vibration

A movable optical lens array that uses acoustic radiation force was investigated. The lens array consists of a glass plate, two piezoelectric bimorph transducers, and a transparent viscoelastic gel film. A flexural vibration with a wavelength of approximately 9 mm was generated along the glass plate in the length direction at a frequency of 113 kHz. A cylindrical lens array with a lens pitch of 4.6 mm was fabricated using the acoustic radiation force that was generated by the flexural vibration of the glass plate. The focal point of the lens array can be changed by varying the input voltage. The flexural vibration distribution can be changed by varying the driving phase difference between the two transducers, and the positions of the lenses can be shifted along the length direction of the glass plate. The translation property of this lens array was applied in an optical scanner. The transmitted light could be swept and the maximum angle of refraction was 4.9°.