Microlenses in Groups

The microlenses discussed to this point utilize one tuning chamber or cell. By adjusting the fluidic pressure inside the lens chamber or cell, one can turn a fluidic lens into various other types such as planoconvex, planoconcave, biconvex, biconcave, positive meniscus, and negative meniscus [8,9]. For each lens type, the optical parameters including/and NA can be freely adjusted. 

Zhang et al. formed a fluidic adaptive lens consisting of two back-to-back PDMS fluidic chambers, each covered by a thin (60 pm) PDMS membrane [12]. A thin glass slide (150 pm) was sandwiched between the two lens 

Fluidic control system for fluidic adaptive lenses. (Source Zhang, D.Y., N. Justis, and Y.H. Lo. 2004. Fluidic adaptive lens of transformable lens type. Applied Physics Letters, 84(21), 4194M.196. With permission.) 

The chambers in layers 2 and 3 (chambers 2 and 3) were connected and created a single cross-shaped chamber in the middle plane of the device. The chambers in layers 1 and 4 (chambers 1 and 4) were separated from chambers 2 and 3 by two flexible membranes about 200 pm thick. The two 

The cross-shaped chamber in the middle plane was filled with a liquid having a high refractive index fi2- Chambers 1 and 4 were filled with another liquid with a lower refractive index n. The optically fimctional area of the device was in the center where the two membranes overlapped. Differences in the pressures of the liquid in chamber 1 (Pj), and in chambers 2-3 (P2) caused bending of membrane A. 

---