A low cost flexible electro-dynamic planar loudspeaker

Jium-Ming Lin,Cheng-Hung Lin,Ubadigha Chinweze Ukachukwu

doi:10.21595/jve.2015.16753

Abstract

This paper proposed a low cost flexible electro-dynamic planar loudspeaker (FEPL). The structure is very simple such as a flexible thin film diaphragm (polyimide) electroplated traces of copper coil above a flexible magnetic placed in the bottom of cavity, thus forming a seamless integration of electromagnetic actuation and planar flexible structure. The advantage is that it can be used in flexible electronics or can be deployed on the surface of any object easily. To optimize the performance, this study made detailed analyses on the thickness of cavity, magnet and coil, magnet polarization, and diaphragm dimension. Note that as the cavity height increasing, the magnetic flux densities of both vertically and horizontally polarized magnet are decreased. But they are nearly constant over the surface with the same height for the vertically polarized magnet. On the other hand, as the cavity height of the horizontally polarized magnet increases, the magnetic flux densities would be decrease rapidly at the locations moving farther away from the center point. These effects are not discussed in previous literature of study.

Highlights

Flexible electronics has been a hot research and development topic in the electronics industry since the past few years
Many different actuation mechanisms are employed for electro-acoustic transduction, such as electromagnetic [4, 12,13,14,15,16], piezoelectric [5, 6], electrostatic [8, 17], and electro-thermal [18,19] actuation mechanism
The flexible and transparent loudspeakers using piezoelectric actuation mechanism were developed [3, 5] by using PVDF as the piezoelectric polymer as radiator

Summary

Introduction

Flexible electronics has been a hot research and development topic in the electronics industry since the past few years. Industrial Technology Research Institute (ITRI) Taiwan in 2009 filed a patent [17] of an electrostatic actuated ultrathin flexible loudspeaker, it was able to produce sound within 200 Hz-20 KHz, and can be operated in medium and high frequency [11]. They combined arrays of tiny, bendable speakers to produce speaker systems of almost any size using standard inkjet printing on substrate of paper or plastic and a thin metal. This study has explored the possibility to develop a flexible electro-dynamic planar loudspeaker using finite element analysis in COMSOL. The paper is organized as follows: the first section is an introduction; the part illustrates the FEPL structure configuration and optimization method; Section 3 is results and discussions; the last part is a conclusion

FEPL structure configuration and design

Results and discussions

Conclusions