Printed loudspeakers

They are one of the most unique set of speakers in the world, yet they look decidedly unremarkable. Paper thin and covered in a sponsor's name, they hang here on the wall of a display booth at the world famous Düsseldorf print expo, DRUPA, hidden in amongst huge printing presses and elegantly dressed hostesses in Hall 15.

Dr Georg Schmidt from Chemnitz University of Technology (TU Chemnitz) has been involved in the project since it started two-and-a-half years ago. He says the new technology functions differently to traditional speakers. 

"Electrodes are attached to both ends of a piezoelectric material - in this case a polymer," Schmidt told DW. "That stretches and retracts once it is exposed to voltage, and that creates oscillation. That then moves across the paper surface and is transmitted as sound."

The most notable omission from these speakers are magnets. Magnets are used in most loudspeakers to create the force needed to make the cone of the speaker to move. With this new technology, however, the piezoelectric material does the moving itself, meaning the speakers can be paper thin.

The interest from potential buyers at the DRUPA trade expo is high. But Schmidt says there are still some improvements that need to be made before the product can come onto the market. 

"At the moment a small amplifier is being used to improve the sound," Schmidt said, "we need to solve these problems in our future research."

Other uses for printed electronics

The printable loudspeakers are not the only unique product that the Print and Media Institute at TU Chemnitz has produced in the past few years. A tree made out of solar-panel leaves is also on display at the expo.

Professor Arved Hübler heads Schmidt's institute and has written a book about the increasing role of printed electronics. He says new markets are developing every day in the field.

"Printing is undergoing a revolution," said Hübler. "In this internet age, the traditional print media is being called into question, especially on issues of speed."

Schmidt and Hübler predict one of the initial major uses of their new idea will be the creation of audio advertising posters and packaging.

Talking soft drinks

But what would it be like at your local supermarket if you were faced with packaging on bottles, playing music or adverts at you? Guests at the Düsseldorf trade expo had mixed views.

"We are inundated with information as it is," a visitor called Norman said. "When I'm buying a drink, I know what I want. I don't need bottles talking to me."

Anja, on the other hand, says price will be the determining factor when people are deciding to buy a product with attached loudspeaker systems. 

"As long as it doesn't cost a lot more and isn't too expensive, I'd be interested," she says.

But if an industry wants to invest in these sorts of products, there is a feeling that cost won't be an issue because of mass production methods.

"Because of the potential to do large runs of prints, I predict more and more electronic products - which at the moment are being manufactured at a high cost - will be simply printed in the future," says Professor Hübler from TU Chemnitz. "Then they will be available on paper, on foil or on flexible materials."

So, musical advertising banners and soft drink bottles could be just around the corner. But scientists say it will be some years before the finished product hits the market.

Author: André Leslie
Editor: Zulfikar Abbany