Electronics Production | June 11, 2008
All Eyes on Printed Electronics
Printed and potentially printed electronics was first seen as a way of sharply reducing the cost of everything from lighting to personal electronics. That remains an objective.
However, it is also proving to be a way of providing electronic and electrical devices that were previously impossible to manufacture. This is leading to components and products that can re-invigorate the following markets: Little wonder, then, that analysts see printed electronics rising exponentially to around $300 billion in twenty years' time, with the demand for conductive inks alone reaching several billion dollars yearly in little more than five years from now. Little wonder that over 1500 organisations across the world are now doing major work in this area, about half of them being academic. That is about twice the level of interest and investment of only three years ago and it goes beyond the well publicised organic electronics - indeed, half the materials being developed and used for printed electronics are inorganic. The number of patents in all aspects is sharply increasing as giant corporations down to start-ups announce a raft of exciting new inventions. The conventional silicon chip is hitting the buffers. Major problems include the cost of the research and development supporting improved production rising exponentially and the cost of silicon factories rising exponentially. This is what Professor Neil Gershenfeld of Massachusetts Institute of Technology calls the Inverse Moore's law. Making small quantities of chips is already very expensive and design and production changes are very slow and expensive. The next step down in transistor size (to reduce cost and provide cleverer circuits) results in short life of the chip. In addition, making chips ever smaller means you cannot subsume large components such as displays, batteries, antennas, microphones etc. They cannot be put on top of the tiny chip so they all have to be connected alongside thus creating something big and unreliable. Printed electronics can get over almost all of these problems but it can also take us into a new world. Here we have the magic of the new metamaterials, with their negative refractive index and other surreal properties promising previously impossible devices, from the cloak of invisibility to unusually small RFID labels. For example, some metamaterials are flexographically printed to give the necessary microscopic three dimensional patterns over a wide area, such as split ring resonators on microwires. We now have the reduction in melting point of metals by a factor of ten achieved by printing them in particles of only a few nanometers across. They can then be annealed on something as delicate as acetate film. What are the new products soon to be launched in biodegradable paper electronics and in electrophoretics where the display uses no electricity until it is changed? The leaders are being eagerly followed as they push the boundaries forward, from tightly rollable electronics and power to edible electronics. Development of exciting new materials is central to this revolution, there being rapid advances in performance thanks to the new nanosilicon semiconductors in printed transistors and photovoltaics, new organic materials printed in the form of batteries, inorganic compounds both as semiconductors and as photovoltaic films, some of which work off heat as well as light. Will printed copper finally replace the printed silver used in everything from touchpads and testers on Duracell batteries to smart skin patches for drug delivery? Where will the new concept of origami electronics take us beyond the foldable two meter disco light shown below? Packaging that is refolded after use into a useful electronic or electrical product is one hot idea for brand enhancement while enhancing environmental credentials. The end result is the replacement of billboards, posters and books with reprogrammable printed electronic film. Smart packaging will inform, prompt, warn and entertain and record when you took you pills thanks to printed logic, moving colour displays, light, sound and electronically triggered aromas. Medical test instruments will become everyday disposables kept in your pocket. The move of healthcare from hospital to home and on the move is also facilitated with printed diagnostic patches and other affordable inventions. The effects can be multiplied when electronics and electrics are printed onto smart substrates. These include self healing plastic recently developed in France and "Polymer based Ultrasonic Paper PUP" from ITRI Taiwan. Physiotherapy and large area motion detectors are envisaged that will use the latter. Polymers have recently been demonstrated that change electric properties when stretched and electroactive polymers change shape under electrical bias. Image Source: www.vtt.fi