Design and modeling of an acoustically excited double-paddle scanner

Abstract

Dynamic analysis is an essential factor in the design, fabrication and optimization of micro-systems. Micro-scanners are currently subjected to wide research work. In this paper, the dynamic behavior of a monolithic single-crystal silicon microstructure is investigated. The microstructure used is a double-paddle scanning mirror for laser applications. It consists of two similar plates (wings) connected to another plate (mirror) and is suspended by one torsion bar. The dynamic analysis is conducted numerically, using finite element analysis. The numerical modeling is described. The numerical results are validated experimentally by measuring the frequency response functions collected at some points on the scanner surface. The experimental modal analysis is performed using a laser Doppler vibrometer and an acoustic excitation device. The excitation device consists of a polyester resin mount with two conic-shaped ducts which give access to the back of the two wings from one side and to two mini loudspeakers on the other side. This excitation device was used and good agreement was found between the numerically predicted and the experimentally identified modal parameters. The non-intrusive excitation mechanism and the optical measurement techniques used in the experiments are discussed. A high quality factor is identified for the chosen operational mode shape.

Design and modeling of an acoustically excited double-paddle scanner

“…The existence of this acoustic cavity may have a significant effect on the dynamic characteristics of the DPS. For this reason, the influence of the air/structure interaction was investigated in a previous work conducted by Ahmida et al (2003a). In this work new structural modes were observed.…”

Tuned-Sinusoidal Method for the Operational Modal Analysis of Small and Light Structures

“…This method is suitable for small and light structures. Ahmida and Ferreira [6] tested it on a very small structure, consisting of silicon plates. However, the method does not include the mass normalisation of the mode shapes, because the actual excitation force on the structure is not measured (only the signal that is sent to the loudspeakers is measured).…”

“…A similar method to [6] was also used by Xu and Zhu [7]. The structure was excited acoustically (with white noise) and the response was measured at individual points with an LDV.…”

A single-layer tilting actuator with multiple close-gap electrodes

“…Tilting elements are typically suspended using compliant torsion axes [11] or bending flexures [12] while an actuating torque is provided by an electromechanical transducer. While a large variety of actuation methods were developed, including magnetic actuation [13,14], thermal actuation [15], actuation based on the use of piezoelectric materials [16] and even acoustic actuation [17], electrostatic actuation remains the most widely used due to its efficiency, low power consumption, simplicity, compatibility with established fabrication processes and common materials used in microfabrication as well as integrated circuit compatibility [18].…”