Fabrication and evaluation of variable focus and large deformation plano-convex microlens based on non-ionic poly(vinyl chloride)/dibutyl adipate gels

Abstract

In this paper, we propose a variable focus microlens module based on a transparent, electroactive, and non-ionic PVC/DBA gel. A non-ionic PVC/DBA (nPVC) gel on an ITO glass was confined beneath a rigid annular electrode, and applied pressure squeezed a bulge of the nPVC gel into the annular electrode, resulting in a hemispherical plano-convex nPVC gel microlens. The proposed nPVC gel microlens was analyzed and optimized. When voltage is applied to the circular perimeter (the annular electrode) of this fabricated microlens, electrically induced creep deformation of the nPVC gel occurs, changing its optical focal length. The focal length remarkably increases from 3.8 mm up to 14.3 mm with increasing applied voltages from 300 V to 800 V. Due to its compact, transparent, and electroactive characteristics, the proposed nPVC gel microlens can be easily inserted into small consumer electronic devices, such as digital cameras, camcorders, cell phones, and other portable optical devices.

Fabrication of a High-Performance Bending Actuator Made with a PVC Gel

“…Because the crystalline region of PVC is a turbid state, increase of the PVC molecular weight decreases the optical transmittance [23,24]. To show this effect, we prepared three PVC films (1 mm thick) with different molecular weights and measured their transmittance on indium tin oxide (ITO) glass using UV-vis spectroscopy (HP 8452, HP, Palo Alto, CA, USA).…”

“…Previously, we synthesized PVC and dibutyl adipate (DBA) to fabricate an electroactive PVC gel [23,24]. When a voltage was applied to the developed electroactive PVC gel, the plasticizers in the PVC matrix migrated to the anode side with dragging PVC chains, consequently deforming the PVC gel.…”

Tunable‐focus negative poly(vinyl chloride) gel microlens driven by unilateral electrodes

“…Since the sectional surface has been smoothly polished, the viscous PVC gel is very sticky on it . It is noted that both the anode and the cathode are on the same side of the PVC gel, which is different from the sandwich‐like structure of those microlenses in previous work . The plastic part of the electrode assembly is necessary for the microlens.…”

“…So far, electroactive polymers have drawn attention for microlens as an alternative of liquid ones. Electroactive polymers are responsive to external stimuli of electric fields, which are used for tunable lenses, such as dielectric elastomers as actuators, transparent ion‐implanted EAPs, and poly(vinyl chloride) (PVC) gels …”

“…It was reported that when a voltage was applied between the two electrodes, the PVC gel would creep along the surface of the anode or bend around the anode edge and adhere to the surface of anode . Particularly, in the work of Hirai et al ., Kim et al ., and Kim and coworkers, the PVC gel is sandwiched between a metal anode with a hole and a transparent cathode of indium–tin oxide glass. The glass has its own refractive index and would weaken the clarity of the microlens.…”