Mechanical characteristics of laminated film vibrator using an ultra-thin MEMS actuator

Abstract

This paper describes fabrication of a laminated film vibrator that uses an ultra-thin micro-electric mechanical system (MEMS) and the effect of lamination on the actuator. The thickness of the ultra-thin MEMS actuator fabricated by ultra-thin MEMS technology was 7.26 µm, making it especially flexible. The vibrator was actuated by applying voltage on a lead zirconate titanate (PZT) thin film. Then, we applied a lamination method to package the actuator. However, the lamination structure influenced the mechanical characteristics of the vibrator. Therefor, we evaluated the effect of the lamination structure on the static and dynamic characteristics of the laminated film vibrator. Four types of laminated film vibrators with different layer structures were prepared, and their displacements and velocity were measured when DC and AC voltages were applied. The maximum displacement of the cantilevers constructed from the laminated film vibrator (PZT: 11 mm  11 mm) was 113.3 µm at 40 V DC. This result is in good agreement with the calculated result. Furthermore, the dynamic characteristics from both the experimental and simulated results confirmed that the resonant frequency of the laminated film vibrator depends on the film structure. This means the dynamic characteristics can be adjusted to suit the application. Applications of this laminated film actuator include use as a flexible hybrid electronics (FHE) haptic device for monitoring vital signs.

Lever Mechanism for Diaphragm-Type Vibrators to Enhance Vibrotactile Intensity

“…A resonant frequency change due to mounting the mechanism and applying load on the vibrator might also enhance vibrotactile intensity at its frequency. Although we confirmed that the vibrators we developed had no resonance within the vibrotactile bandwidth (∼500 Hz), with no load applied to the vibrator [18], it is insightful to measure the resonant frequency with a load considering that the skin is pressed against the vibrator. Therefore, Experiment 1 (Section III-A) measures the displacement frequency response of the vibrator with the lever mechanism and load.…”

A Review of Ultrathin Piezoelectric Films

“…Since the discovery and synthesis of piezoelectric materials, researchers have gradually realized that piezoelectric technology can be widely used in biomedicine [1][2][3], flexible electronic devices [4,5], flexible generators [6][7][8][9], ultrathin film vibrators [10], piezoelectric photoelectronic solar cells [11,12] and many other fields. Many kinds of piezoelectric materials have been reported to have high piezoelectric properties and high electromechanical coupling, such as epitaxial wurtzite Sc x Al 1-x N ultrathin films [13] and nanocomposite [14,15].…”