University of Michigan

Other

Peter D Washabaugh

Khalil Najafi

Luis P Bernal

Hanseup S Kim

Aaron A Astle

Tsung-Kuan A Chou

A MEMS-fabricated microvacuum pump assembly is provided. The pump assembly is designed to operate in air and can be easily integrated into MEMS-fabricated microfluidic systems. The pump assembly includes a series of pumping cavities with electrostatically-actuated membranes interconnected by electrostatically-actuated microvalves. A large deflection electrostatic actuator has a curved fixed drive electrode and a flat movable polymer electrode. The curved electrodes are fabricated by buckling the electrode out-of-plane using compressive stress, and the large deflection parallel-plane electrostatic actuators are formed by using the curved electrode. The curved electrode allows the movable electrode to travel over larger distances than is possible using a flat electrode, with lower voltage. The movable electrode is a flat parylene membrane that is placed on top of the curved electrode using a wafer-level transfer and parylene bonding process. Using this approach, large out-of-plane deflection of the parylene membrane is achieved using a voltage smaller than is achievable using flat parallel-plate electrodes.

Micropump assembly for a microgas chromatograph and the like

A method of low-temperature (150-300&#xb0; C.) patterned wafer bonding of complex 3D MEMS comprising providing a first pre-processed wafer having a first surface and a second pre-processed wafer having a second surface. Photosensitive benzocyclobutene (BCB) polymer is then applied to the first surface of the first wafer in a predetermined pattern to define a bonding layer. The second wafer is then bonded to the first wafer only along the bonding layer.

Low-temperature patterned wafer bonding with photosensitive benzocyclobutene (BCB) and 3D MEMS (microelectromechanical systems) structure fabrication

The design of transducers utilizing finite length sensor paths is discussed. Within the framework of linear elastostatics of an isotropic homogeneous material the normal, transverse, and shear components of strain along a path can be integrated over a finite length to separate and yield external loading components. These displacement measurements over a long distance accommodate the use of fiber optic displacement sensors. The use of optical interferometric sensors in contrast with electrical strain gauges, has the potential to allow the precision and range of the component measurement to scale with the geometry of the device rather than the maximum strain in the instrument. It becomes possible by virtue of these scaling properties to construct a better transducer. The design of transducers that measure all six resultant-load components using both electrical strain gauges and fiber-optic interferometric sensors are described. An advanced torsion sensor and a linear acceleration transducer are also discussed. In addition, a 'null' transducer that is potentially useful as a 'structural integrity' sensor is presented. Finally, practical consideratios in the design of finite length sensor path transducers are noted.

Growing community of inventors

Ann Arbor, MI, United States of America

Peter D Washabaugh