Adaptive dielectric liquid lens

Abstract

A tunable-focus liquid lens using dielectrophoretic effect is demonstrated. When a voltage is applied to a dielectric liquid droplet, the generated electric field inside the droplet is inhomogeneous. As a result, the liquid bears a dielectric force and its surface profile can be reshaped which causes the focal length to change. Adaptive lenses with different apertures are fabricated and their performances evaluated. In comparison to the patterned-electrode liquid lenses, our lens uses continuous electrode which is much simpler for fabrication.

Fabrication of Microlens Arrays with Well‐controlled Curvature by Liquid Trapping and Electrohydrodynamic Deformation in Microholes

“…But these thermal approaches can only be used to fabricate microlenses with convex surfaces and are faced with a diffi culty in controlling the lens surface geometry or focal length. Recently, an adaptive or tunable focal liquid lens based on electrowetting actuation, [ 10 , 11 ] a liquid-dielectrophoretic (L-DEP) drive, [ 12 ] or the thermoresponsive manipulation of liquid droplets, [ 13 ] has shown an adequate controllability of the lens curvature or focal length by external an electric fi eld or by heating, which changes the geometrical profi le of the lens. However, it can be very hard (if possible) to achieve a high fi ll-factor or a stable curvature for the MLA over a large area, due to the nature of droplet-wise manipulation which causes merging of the droplet array, and also due to electrothermally induced liquid evaporation which causes a volumetric shrinkage of the droplets when working for a long time.…”

Adaptive Liquid Lens Actuated by Droplet Movement

“…According to the difference of the filled materials, it can be roughly classified into two categories: liquid crystal (LC) lens [1][2][3][4][5] and liquid lens [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. An adaptive LC lens usually employs an OPEN ACCESS inhomogeneous electric field to make the LC molecules reorient to produce a gradient refractive index profile.…”

“…Since the response time depends on the LC layer thickness and the size of the LC lens, it is more suitable for making microlens which constrains the real applications in imaging systems. There are three common operating mechanisms to design a liquid lens: electrowetting effect [6][7][8][9][10][11][12][13][14], dielectric force [15][16][17][18], and fluidic pressure [19][20][21][22][23][24].…”

Miniaturization of dielectric liquid microlens in package

“…Tunable liquid lenses that adjust focal lengths without movable mechanical parts emerge to be adopted in systems that include adaptive lenses, 1 endoscopes, 2 light valves, 3 optical communication systems, 4 and barcode readers. 5 Two actuation approaches, mechanical and electric energy, were applied.…”

“…The liquid microlens encounters drift of liquids, leading to unstable optic axis at the rest state and during actuation. 1,12 A cavityshaped polymer on indium tin oxide electrode was proposed but image resolution still remains a question due to structures where light passes through. Unlike macroscale liquid lenses, voltageeffective design is required to actuate the liquid microlens.…”