How to fix an ultrasonic variable-focus liquid crystal lens for substrate-mountable applications

Abstract

This paper proposed a board-mounted ultrasonic variable-focus liquid crystal (LC) lens. The lens controls the focus using the acoustic radiation force generated by the resonant flexural vibration mode. The LC lens was fixed to an aluminum substrate with a hole whose aperture corresponded to the inner diameter of the transducer. The part of the LC lens attached to the substrates functioned as a fixed condition, and the flexural vibration mode was successfully generated. The fixed lens exhibited a gradual focal change with current, confirming that fixing the condition affected the rate of focal change.

Acousto-thermal birefringence of iron(III) chloride using ultrasound flexural standing wave

“…21) These ultrasound LC lenses can be mounted on an electronic substrate by fabricating a hole with a diameter that corresponds to the transducer's inner diameter, enabling use of LC lenses in substrate-mountable applications. 22) Although LC materials can realize large refractive index changes, the physical mechanism behind the change in molecular orientation in the thickness direction induced by external forces is somewhat complex in the case of large LC layer thicknesses of more than 50 μm; the molecular orientation is determined by a combination of the external force, the collective elasticity of the LCs, and the anchoring force of the orientational films. In our previous report, we primarily investigated changes in the birefringence of α-iron(III) oxide colloids in an ultrasound standing-wave field and found that while ultrasound vibration can change the birefringence, its spatial distribution remains independent of the ultrasound vibrational distribution.…”