No abstract

This paper presents a generalization of the hydrodynamic focusing technique to three-dimensions. Three-dimensional (3-D) hydrodynamic focusing offers the advantages of precision positioning of molecules in both vertical and lateral dimensions and minimizing the interaction of the sample fluid with the surfaces of the channel walls. In an ideal approach, 3-D hydrodynamic focusing could be achieved by completely surrounding the sample flow by a cylindrical sheath flow that constrains the sample flow to the center of the channel in both the lateral and the vertical dimensions. We present here design and simulation, 3-D fabrication, and experimental results from a piecewise approximation to such a cylindrical flow. Two-dimensional (2-D) and 3-D hydrodynamic focusing chips were fabricated using micromolding methods with polydimethylsiloxane (PDMS). Three-dimensional hydrodynamic focusing chips were fabricated using the "membrane sandwich" method. Laser scanning confocal microscopy was used to study the hydrodynamic focusing experiments performed in the 2-D and 3-D chips with Rhodamine 6G solution as the sample fluid and water as the sheath fluid.[1027]

Abstract-We have designed, fabricated, and demonstrated large vertical displacement vertical microlens scanners with low ( 10 V) driving voltage using silicon-on-insulator technology. The unique isolated and pre-engaged vertical comb-drive sets and the coupled-torsion flexure design provide both upward and downward piston motions, as well as low driving voltages.Single-directional devices demonstrate maximum static downward displacement of 8 m at 10 dc . Bidirectional devices demonstrate vertical actuation from 6.5 to +9 m at max 12 dc , and a vertical displacement of up to 55 m peak-to-peak is achieved at the resonance near 400 Hz. The lens motion shows piston motion with a small tilt angle of less than 0.034 and the compensation of the tilt using an isolated comb bank is demonstrated.

No abstract

Abstract-We introduce a backside island isolation method for silicon-on-insulator (SOI)-based microelectromechanical systems technology and demonstrate vertical comb drive-based two-dimensional gimbaled micromirrors with large static rotation using the isolation method. The proposed isolation method provides electrical isolation and mechanical coupling of SOI structures without additional dielectric backfill and planarization by utilizing timed etched backside handle wafer structures. The backside island is a hidden layer beneath the gimbal and allows independent application of actuation potentials to the gimbal and inner mirror. We developed the fabrication process that accommodates the backside island isolation structures into an established vertical comb drive process, thereby allowing implementation of two-axis gimbaled structures. The maximum static optical deflections of the gimbal and mirror are 46 and 15 , respectively. Index Terms-Backside island isolation, deep reactive ion etching (DRIE), micromirror, raster scanning, silicon-on-insulator (SOI), two-axis scanner, two-dimensional (2-D) scanner, vertical combdrive.