ENIAC 1946 System miniaturization brings us function enhance

ENIAC (1946) System miniaturization brings us: function enhance more reliable save material and energy TX-0 cost down (1956) IBM 360 (1964) 第一台电子管计算机 第一台晶体管计算机 Osborne I (1981) Libretto 110 CT Today 第一台集成电路计算机 第一台便携式计算机 1

Look into the MEMS • MEMS is never a science category but a technical solution for many application fields. However, MEMS needs many categories of scientific and engineering knowledge • MEMS is Art and Science, needs not only IQ but also EQ • Along with shrinking from Macro-machine to MEMS : 1. The most knowledge already existing 2. But two things adapting mechanics to micro scale that are of great importance in MEMS 1) Electrostatic effect; 2) Air damping control 2

Electrostatic Effect Comb-drive • The work initiated by Bill Tang and Roger Howe should have been cited for many times. • But actually no people would like to do so. 3

Liquid Manipulation Using Electro. Wetting On Dielectric (EWOD) by C-J Kim et al，UCLA 4

Wanted Electric feedback damping conditioning -ke / km = Electrostatic Driving Electric Tuning ’ = /(1+ )1/2 f 0’ = f 0 (1+ )1/2 C km > 0, ke < 0 f 0 = [(km- ke )/m]1/2 Electric feedback 5

So now you know: How does E and M couple each other in MEMS 6

Electrostatic Pull-in Xinxin Li et al, J. Micomech. Microeng. , 2000 7

Avoiding in MEMS Sensor offset: sensitivity: nonlinearity: MH Bao et al, Sens. Actuators, 2002 8

Improvement: Push-pull balance and feedback loop 9

Positive utilization of Pull-in DMD by TI 17µm 10 H Yang et al, IEEE SENSORS 2005

Air damping Problem in existing Christian Model for rare air or low vacuum MH Bao et al, J. Micromech. Microeng. 2003 11

Bao Model based on energy method l 1. Energy method for Q, l 1. 3. Momentum method for Q，big difference from with test verification 2. Christian Model testing results Influenced by adjacent electrode considered 2. That not considered Related to geometry 3. That not related 12

I－test，II－Christian，III－Bao model 13

Modified Reynolds Equation for squeeze film damping of perforated plate structure Equivalent cell radius rc Hole radius ro b=ro/rc MH Bao et al, J. Micromech. Microeng. 2002 14

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So now you know: Why I chose this Bao’s textbook for your course Now I assign the 1 st homework: pre-reading 17

The 2 nd part of your homework: Thinking about 1. What is MEMS by your thinking? try to give your own definition. try your best to use four English words with their capitals in the order of M, E, M and S For example: Miniaturized Everything Making Sense 2. Why people use MEMS? i. e. the advantage of MEMS 3. Who is the Korean researcher doing micro-fluidic bio-MEMS? And who does NEMS probes 4. How MEMS can be put into volume production? i. e. make big money 5. Which kind of MEMS work you are the most interested in? 18