Scientists create near-invisible speakers

24 November 2008

In a surprise discovery, scientists found they had created the world's first transparent, flexible and stretchable loudspeaker. They say its potential uses are endless - but what do experts from the world of design think? Antenna tunes in to find out more...

The prototype speaker.

Image: Shoushan Fan

Carbon nanotubes are so tiny that you could fit 50,000 of them across the width of a human hair.

Image: Wikimedia Commons

The research team were experimenting with tiny tubes of carbon molecules known as nanotubes when they were amazed to find that simply connecting sheets of this material to an electric current produced a loud sound.
Normal speakers generate sound by producing vibrations, but the nanotube sheet stays completely still when it produces sound. The scientists think that the electric current heats the sheet and changes the pressure of the surrounding
air - which generates the sound.

This close-up image of the carbon nanotube sheet was taken with a powerful electron microscope.

Image: Shoushan Fan

The sheet heats up to 80 degrees Celsius as it plays sound, but the researchers say by improving the design they could cool it down for everyday use. They suggest that their discovery could replace the relatively bulky loudspeakers on electronic kit such TVs and music players.
'Because the sheets are transparent, flexible and stretchable, they can be made into any shape without changing the sound quality. These unique properties offer a big space for the imagination of designers,' says research leader Shoushan Fan.

Shoushan Fan (right) and researcher Kaili Jiang (left), nanotechnology experts, Tsinghua
University, China.

Image: Shoushan Fan

Antenna asked some designers and materials experts how they thought the invention could be used...
'We can imagine the discovery being used throughout the arts, in architecture, fashion, exhibitions, live events and interior design,' say Amy Winters and Kseniya Zagorodnyuk, futuristic fashion designers.

Amy Winters and Kseniya Zagorodnyuk, fashion designers and founders of Couture Clubbing.

Image: Couture Clubbing

'We'd like to see it used for interaction design - enabling people to interact with their environment. For example, an event could be really evocative if the spectator could wear a live audio jacket, becoming part of
the performance.'
Sharon Baurley, a textile expert, says: 'I think it's a fantastic discovery. The fact that it's flexible and would still work if ripped is great. One application could be interactive materials in the home, office or car that respond to your actions with sound.'

Sharon Baurley, textile expert, Central Saint Martins College of Art and Design.

Image: Sharon Baurley

'This finding seems pretty amazing,' agrees Markys Cain, a materials expert from the National Physical Laboratory. 'As it's transparent you could place it over windows, and its flexibility means that you could make singing balloons! This is yet another use for carbon nanotubes - will their list of properties never end?'
The question is whether this material can be made in vast quantities and be affordable enough to use in everyday items. If it can, it sounds like this invention might be catching people's ears in all kinds of places.

Here, a speaker sheet is connected to an iPod - could this one day become the slimmest docking station ever?

Image: Shoushan Fan