A lightweight, flexible loudspeaker that looks like a thick sheet of foil could signal the beginning of the end for conventional speakers in some applications.
The speakers which are only 0.25mm thick are cheap to manufacture and could be concealed inside ceiling tiles or car interiors, or printed with a design and hung on the wall like a picture - its size and flexibility means it can be used in all sorts of areas where space is at a premium.
The researchers say that they are perfect for use in public spaces such as railway stations, where many distorted announcements are made from existing PA systems. The sound produced by the Flat, Flexible Loudspeakers (FFLs) can be directed straight at its intended audience. The sound volume and quality does not deteriorate as it does in conventional speakers, which means that public announcements in passenger terminals, for example, could be clearer, crisper, and easier to hear.
All speakers work by converting an electric signal into sound. Normally, the signal is used to generate a varying magnetic field, which in turn vibrates a mechanical cone, thus producing the sound.
The technology developed by the University of Warwick is a combination of thin, conducting and insulating materials resulting in the development of a flexible laminate, which when excited by an electrical signal will vibrate and produce sound.
The speaker laminate operates as a perfect piston resonator. The entire diaphragm therefore radiates in phase, forming an area source. The wave front emitted by the vibrating surface is phase coherent, producing planar directional sound waves, which project further than sound from conventional speakers which is why it is suitable for public spaces.
Audio visual companies are investigating its use as point of sale posters for smart audio messaging and car manufacturers are particularly interested in it for its light weight and thinness, which means it can be incorporated into the headlining of cars, rather than lower down in the interior.
The technology is being commercialized through university spin off company Warwick Audio Technologies, who are in negotiations with a number of companies, with a view of bringing a product to market later this year.
We understand that Coventry University has also developed an ultra-thin and flexible loudspeaker working on electrostatic principles. Some time ago they were at the stage of looking for licensing partners to further develop the speakers for commercialization - It is not clear what happened beyond that.
Top image: Dr Duncan Billson, Inventor (courtesy of University of Warwick).
Reference: University of Warwick
For more attend Printed Electronics USA 2009.
