Thursday, May 10, 2012

The Printable Speaker

A team of scientists at the Institute for Print and Media Technology at Chemnitz University of Technology, in Germany, has managed to make paper-thin speaker that can be fabricated at-will, in other words... printed. I foresee this technology leading to very annoying subway posters and greeting cards. The evils of marketing can ruin anything. More here.

But the technology is fascinating. The Chemnitz University team spent over two years on this project. This prototype is  made by printing layers of a conductive organic polymer and a piezoelectric layer  onto a piece of paper. The layers vibrate against each other to produce sound. I just cant figure out how to plug it in. They claim the speaker can produce sounds up to 80 decibels. That is in fact as loud as a freight train. [More on db references here.]  The team did admit the speaker didn't produce much bass. More here.

When most people see the word "polymer" they think plastics but that's not necessarily the case. Polymers can be organic or synthetic. They are just macromolecules comprised of repeating structural units connected by covalent chemical bonds. So you may have been thinking Bakelite is a polymer, and you are right.  But  so are PVC, silly putty, cellulose and even your own DNA. What I'm getting at here is that describing the layer as a polymer isn't very specific.

This is not the first paper speaker. It's just the first printable one. Last year the Journal of Mechanical Science and Technology published a paper on Piezoelectric electro-active paper speakers by Professor Jaehwan Kim  and some grad students at INHA University, South Korea. It described the acoustic characteristics of cellulose electroactive paper (EAPap).  cellulose... yes that's a polymer. The INHA University press release described it's potential in glowing terms:
"...cellulose EAPap is ultra-lightweight, inexpensive, biodegradable, it is advantageous for many applications such as micro insect robots, micro flying objects, microelectro-mechanical systems, biosensors, flexible electrical displays, RFID tags and smart packaging."
(More here.)  It sounds over the top, but even Forbes has been following the story, and with similar levels of enthusiasm, repeating claims that printable electronics may  generate up to $13 billion by 2016. Remember back when technology companies marketed to audiophiles?