Traditional micro-electro mechanical systems (MEMS) actuators have limited stroke and force characteristics. This paper describes the development of a hybrid actuation solution, which utilizes a micro-machined actuator array to provide switching of the mechanical motion of a larger meso-scale piezo-electric actuator. One motivating application of this technology is the development of a tactile display, where discrete mechanical actuators apply vibratory excitation at discrete locations on the skin. Specifically, this paper describes the development, fabrication, and characterization of a 4 × 5 micro-actuator array of individual vibrating pixels for fingertip tactile communication. The individual pixels are turned on and off by pairs of microscopic thermal actuators, while the main vibration is generated by a vibrating piezo-electric plate. The fabrication sequence and actuation performance of the array are also presented. © 2005 Elsevier B.V. All rights reserved.
An anodic bond is modeled as a moving non-material line forming the intersection of three material surfaces representing the unbonded conductor, the unbonded insulator, and the bonded interface. The component mass balance equations, Gauss' law, and the linear momentum equations are cast in a finite-element formulation, which is used to predict the evolution of the sodium ion concentration, electric potential, and stress during the anodic bonding of Pyrex glass and silicon. The method is applicable to the viscoplasticity of solid electrolytes, and the volume and interface free energies can be modified to model electromechanical interface phenomena such as debonding, space charge accumulation and sliding at grain boundaries in ionic crystals, and a cohesive zone theory of piezoelectric fracture.
The rapid development of reproductive biology has created a need for quantifying penetration forces during artificial fertilization. It has been demonstrated that the success of such procedures heavily depends on the mechanics of penetration of the egg's zona and membrane. To quantify the forces during intracytoplasmic injections we have developed a MEMS based force sensor. Deep RIE and fusion bonding are used to fabricate a variable capacitance type sensor. It is designed to measure the penetration force during intracytoplasmic injection of egg cells as well as other applications in the 1-500 μmN force range. The sensor measures tri-axial forces using a system of flexible beams subjected to bending and torsion. The process is relatively simple and allows for easy modification of the force range. A penetration pipette tip is attached to the sensor body using a low temperature bonding technique. Calibration, sensitivity and initial experimental data is provided.