Title :

Creating the Next-Generation Small-scale Machines for Precision Engineering, Microscopy and Biomedical Applications

Speaker :

Dr. Shih-Chi CHEN

Senior Engineer

Nano Terra, Inc., USA

Venue :

Room 215, William M. W. Mong Engineering Building, CUHK

Date :

Oct 11, 2010, Monday
4:00 PM - 5:00 PM

Abstract :

Study of nanoscale phenomena and biological systems has been the focus of researchers across different fields in recent years. Accordingly, small-scale machines such as biological imaging equipment, equipment for nanomanufacturing and instruments for nanoscale research are increasingly needed. These machines/positioning systems must be of small scale in order to achieve viable bandwidth (kHz), high resolution (nanometers), low cost ($10s/device) and high thermal stability (Å/min). Miniaturized precision machines require an integrated structure, powerful and efficient small-scale actuators, well-designed flexural bearings, and control systems. Unfortunately, the current state-of-the-art is not capable of simultaneously satisfying all of these requirements. For example, the design of an endoscopic scanner requires a micro-actuator to simultaneously generate high force (~10mN), stroke (~100μm) and bandwidth (~1kHz).

This talk will address these issues with examples from two projects: (1) Development of two-photon endomicroscope with sub-cellular volumetric imaging capability. The heart of the instrument is a thermally actuated 3-D micro-scanner that runs at 3.5kHz x 100Hz x 30Hz throughout a 125x200x200 μm3 volume. This performance can be achieved by thermomechanical actuators (TMAs) through the use of two new design techniques that I developed—Geometric Contouring and Mechanical Frequency Multiplication. (2) Development of the µHexFlex, the first microscale six-axis nanopositioner that provides 0.6 nanometer repeatability and angstrom level resolution. The µHexFlex, which has a 2.5-mm device envelope, sandwiches a layer of silicon dioxide between two layers of silicon. The integrated TMAs can exert both in-plane and out-of-plane forces on the central stage and flexure bearings, and thus enable six-axis positioning.

The presentation will be concluded with future research directions, including the development of the next-generation small-scale biomedical devices/machine elements, and issues relating to light microscopy and endoscopy for minimally-invasive imaging.

Biography :

Dr. Shih-Chi Chen received his B.S. degree in power mechanical engineering from the National Tsing Hua University, Taiwan, in 1999. Subsequently he received his S.M. and Ph.D. degrees in mechanical engineering from the Massachusetts Institute of Technology, Cambridge, in 2003 and 2007, respectively. Between 2007 and 09, he was a joint Research Fellow at the Laboratory for Manufacturing and Productivity of MIT and Wellman Center for Photomedicine of Massachusetts General Hospital, Harvard Medical School, where he applied his engineering knowledge to solve biomedically/clinically-oriented problems. In 2009, he joined Nano Terra, a start-up company founded by Prof. George Whitesides at Harvard University, to lead and manage multiple interdisciplinary project teams in the areas of Microcontact Printing, automated precision machines, and flow system design. Dr. Chen was the recipient of a 2003 R&D 100 Award for the design of a microscale six-axis nanopositioner. His research is focused on the design and development of next-generation micro- to meso-scale electromechanical devices and optical systems for precision and biomedical applications.

    **************************************** ALL ARE WELCOME ****************************************

Enquiries: Ms. Winnie Wong or Prof. Wen J. Li, Department of Mechanical and Automation Engineering, CUHK at 2609 8337. *MAE Series (2010-11) is contained in the World-Wide Web home page at http://www3.mae.cuhk.edu.hk/maeseminars.php#mae.