Emerald Group Publishing Limited
Copyright © 2011, Emerald Group Publishing Limited
Printed Electronics 2011 Düsseldorf Germany 5 and 6 April
Article Type: Conferences and exhibitions From: Microelectronics International, Volume 28, Issue 3
Owing to unfamiliarity with the transportation system of Dusseldorf, both above and below ground, we arrived on the first day just in time to hear the man from Mars saying that 29 per cent of shoppers like chocolate, but tend to avoid the chocolate aisle in a supermarket, and he wanted to know how printed electronics (PE) could help steer these wayward shoppers down towards his products. On that entirely reasonable request hinges the whole question of PE. PE is seen as a solution to problems that have yet to arise, and yet, and yet. There are plenty of applications, but the need is for them to be driven, not led. The supplier push far exceeds the user pull at this moment in time, although there is evidence of some imaginative use of PE in consumer products wherein lies volume. As the man from Mars summarised, he wanted to NAG, getting products noticed, where the products were attractive and where customers got the message. He wanted to convey the brand message in a way that supports the brand, where the message and the carrier were fully aligned. He felt that PE could do this, but it should be a means to an end, not an end goal. Let’s innovate together, he said. A Mars bar code, possibly?
According to Raghu Das of IDTechEx, $44 billion will be the projected value of the PE market by the end of the next decade. Right now the market is a modest $2.2 billion, dominated by photovoltaics and OLEDs. The use of OLEDs in displays will see the most significant growth, of 35 per cent of these will be printed, 18 per cent flexible.
E-paper has been the big success story; it is used in over $1 billion worth of products. This is a ten-year old technology that became mainstream about four years ago, with e-readers being the dominant application; this is the successful case study of creating a new market from an enabling technology. The Holy Grail will be colour and video, with Hanvon in China being the first, but the ones to watch are Samsung, who have acquired Liquavista, and LG who have acquired I&M. The design of inclusive multi-layer conductors, sensors and actuators printed within plastic mouldings is also making products more attractive to end-users, where novel functionality and originality have great appeal.
To speak about stretchable electronics in mobile devices came Dr Darryl Cotton of the Nokia Research Centre, Cambridge. Located on the university site, his department has been working on nanotechnologies and smart surface materials since 2006. Capital investment of £600 million has been spent in Cambridge start-up companies. What are stretchable electronics? They are a composition of electronic materials and/or components formed across a substrate in a manner to allow the overall substrate to repeatedly deform without failure. Carbon nanotubes fall into this category; they create stretchable electronics using an elastomeric substrate, with rigid island platforms (diamond like carbon, polyimide) and then active devices on top with stretchable inter connects using Au thin film. This has been proved to be reliable to 250,000 cycles. They have followed this by making multi-layered stretchable conductors on silicone polydemethylsiloxane and stretchable transistors on a polyimide island. Stretchable electronics have exciting possibilities for mobile devices which can conform to the human body, can be folded up, and provide a conductive path of minimal intrusion.
Ross Bringans of the Palo Alto Research Centre (PARC) explained how his company had started life under the Xerox label; they run partnerships with new ventures, creating new business, and licensing and technology transfer. They see printed and flexible electronics in two formats – there will be new applications which need flexibility, and products which benefit from flexibility. People want solutions, not technology. They have taken standard circuit technology and made it flexible, using ink-jet technology, and they are now looking at gravure. He described how they had developed inorganic electronics, such as printed sensor tape used on a soldier’s helmet to monitor pressure, acceleration, sound and light, and for monitoring the environment. They used MEMS sensors merged into PE on substrates for array building, and have partnered with Soligie in the field of device fabrication and printing, and with thin film on a 20-bit non-volatile rewritable memory, which is available now.
The future of retailing was displayed by Metro Cash & Carry GmbH, which has Frank Rehme as its Innovation Manager. Metro Stores in Germany are no. 3 in the world, and have started a new future store initiative to meet the needs of people. People are changing, they are ageing, and 50 per cent of the households in Germany have just two people in them. Shopping is, for many, a leisure activity, but buying groceries, for many, is stressful. In their new Future store, they stock over 55,000 articles in a store of 6,000 m2, and serve some 3,000 customers each day. Here, each customer has a “Mobile shopping assistant” which is a mobile phone. The camera in the phone photographs a bar code as you enter the store, which opens your account, and you then photo the bar code on each product. And you pay by photographing the barcode of the summary. Now, they have their own iPhone which is for the shopper to use, complete with cookery book so that culinary inspiration may be sought whilst on the hoof. They use RFID tags in the butcher’s shop for quality assurance, and on the basis that it is better to buy wine you have tasted; they have wine tasting stations, accessed by using a special card so that young people are not compromised. There are five different check-out scenarios, and you pay using your mobile phone. Alternatively, you can order online and pick it up in the store if that is more convenient.
Sascha Voigt is the MD of Printechnologics, a member of the 3M Group. Founded in 2006 as a systems integrator, they are based in Chemnitz, Germany and they licence technology, working with a range of clients including advertising agencies and leading brands. Using a proven and standard printing process, which can be licensed anywhere and at anytime, they produce AirCode technology; this is an identification system, it is near-field RFID functionality, up to 140 bit for unique encoding; it is thin, flexible and invisible, and is fully recyclable. It can be used for tracing and tracking, for identification, and has the major advantage of being able to transfer data contactlessly. It allows direct communication with the customer via their mobile phone, and can be used for on-line shopping, product guides, loyalty programmes, product verification, games, or customer surveys. AirCode can, for example, allow a whole publication/magazine to be downloaded to an iPad. Most interesting technology with enormous implications.
Dr Karsten Danielmeier of Bayer Material Science spoke about light management with polycarbonate films. Polycarbonate has high heat resistance, high-dimensional stability, and a glass like transparency. But what is new? Well, it can be used as a light reflective medium, as a light diffuser, and they have produced light-shaping films. By combining all these three technologies, they produce a backlight unit. The new horse in their stable is Haptic Feedback. Here, they have incorporated high-fidelity actuators and printed electrodes, into what they call a reflex actuator, which sits between the touch screen and the device body. The whole is to be launched soon under the name of Bayfol Reflex™ actuator.
MIT Professor Karen K. Gleason, of the Solar Frontiers Centre, described the various attributes of paper substrates in the field of PE, and the work they are doing with oxidative chemical vapour deposition (oCVD) which is used to produce patterning, which conforms to the paper surface, and has the potential for all-dry processing. It can be used to avoid solvent degradation of the paper, it eliminates wetting issues, and no substrate pre-treatment is needed. The oCVD substrate has good conductivity, and when oCVD is used on PET it is possible to create printed circuitry of great durability.
Patterning can be done down to 60 nm, and roll-to-roll processing is possible. Building photovoltaics with oCVD was described, all vapour deposited, and PV cells are being produced on paper which can be folded without loss, with long-term stability. Much interesting work being done here.
Dr Bonwon Koo from Samsung Advanced Institute of Technology covered organic electronics in three parts. The first was functionality, then features, then application. The latter lending themselves to new applications and new market creation. By 2020, he sees a fully printed intelligent system of integrated electronics being low cost, eco-disposable, comprising an embedded system on integrated PE. Flexible displays are needed for multimedia smart devices, from e-ink or OLED for the displays, pressure sensors as touch sensors, and antenna within an RFID tag. Customers favour a small size for carrying and a large size for viewing, so here a flexible display would be able to fulfil these needs. Polymer semiconductors are suitable options for flexible electronics because of their processability and mechanical flexibility. Demands for the realisation of colour and moving images in e-paper are growing, and Samsung have now made a 4.8″ QVGA colour reflective polymer dispersed liquid crystal display driven by an ink-jet printed polymer thin-film transistor array.
Track 1 in the afternoon was very well attended, as they all were. The first speaker was Mr Eric Penot of JCDECAUX of France who spoke about how his company approaches the subject of PE. His company is the no. 1 outside advertising company world wide, with a €2,350 million turnover. He spoke about Digital Out of Home advertising, where street furniture (bus shelters to you and I) is looked after by JCDecaux in return for exclusive rights to sell advertising space, which is becoming more and more digital. By December 2010, they had 6,670 sites, but out of a potential of one million that is not very big. Most of their digital screens are in China, but the UK is a good market; in the transport mode one can change the offer according to the time of day, and interactive screens are popular, too. Pretty much all of them are plasma, with LEDs accounting for only 1 per cent of the market. The main barrier to digital deployment is electricity consumption, and LEDs are really not suited to outside conditions. There is a long list of requirements for LEDs and OLEDs if they are to meet JCD ambitions. The dream product is a 2 m2 screen, with full video facility, a life of ten years, which needs no maintenance, but is monitorable, and uses very low power. It should also be thin. Something to shoot at for someone.
Blue Spark Technologies have Matt Ream as their VP Marketing. His paper was entitled “The role of printed carbon-zinc thin film batteries in interactive printed media” which is where electronics are used in traditional packaging, print media, materials and designs, enabling increased interactivity. PE are one thing, low power integrated circuits are quite another, but both need power. They need power from a slim source, easily carried and cheap to buy. His company manufactures thin-film batteries using traditional techniques, they are both thin and flexible; the smallest is just 500-μm thick. Using carbon-zinc chemistry, the batteries are manufactured on a roll-to-roll line using screen printing processes. Printing is the key to high volume production, and high volume equals lower costs. 1.5-V cell carbon-zinc battery has + and – terminals on the same side for use with flex circuitry. A magazine cover was demonstrated, showing how a very flexible, lightweight battery was invaluable in getting the customer to interact.
Novalia had sent along Dr Kate Stone, who we had met last year in Dresden. Her interest was in print processes, such as offset litho, gravure, screen, and as an example of how PE could be utilised, they had created a greeting card with a circuit in the image, engaging the recipient in an experience, here the image was of a candle lighting up and responding to being blown out, which would delight a child, doubtless. She showed other examples, such as children’s books with a voice, and interactive packaging, in which a carton becomes a toy. PE is a platform on which one can enable things to happen, said Dr Kate, and all the ingredients are in place. There is the circuitry, there is the power, there are the designers, the creative engineers, the materials in the shape of substrates, there are the components; all that is now needed is the imagination in the ways in which it might all come together to provide a fully interactive world. One just hopes that there is the time for us all to benefit from it, but it may be our grandchildren who will see such things as normal. But we are creating it all now.
Dr David Sime from Soligie had new product development and integration to talk about. His company is just over five-year old and they, like so many, wonder about how the future will shape up. When does PE make sense? When the practical value is revealed, he said.
In this context, he spoke about the role of PE in wearable devices, which are minimally invasive, and are thin, flexible and lightweight. Whilst we have the inks, the dielectrics, the roll-to-roll production, the mass markets were not there yet, it is the low to mid-volume market thus far. He thinks that sensing is where we should be focussing, but there have been difficulties with materials. He detailed the areas of risk, and summarised his view that an efficiently structured PE project requires partners with the flexibility to work effectively in new fields, who have an understanding of materials and development, have the ability to design to meet functional requirements, have manufacturing capabilities suitable to market, and the resources to minimise time to market with new capabilities
At the end of the day, there was an end-user forum, in which all of the speakers formed a panel for discussion with conference delegates. Whilst it may be said that PE are a solution looking for a problem, the problems exist, and what is required is the inspirational expertise to convert the formula. The problems include food problems, medication (medication is responsible for 23 per cent of US nursing home admissions), and there are huge possibilities for healthcare, in consumer electronics, consumer goods, in military applications, toys, advertising and publishing.
There were four different tracks to follow, dealing with no less than 22 different topics within the PE world, and such was the precise timing of the parallel tracks that delegates were able to move from room to room quite easily to listen to the speakers of their choice.
From the De La Rue Group came Dr Philip Cooper to talk about putting power into paper. His company is working with Acreo AB in Sweden on just this. The challenge is to produce a stream of anti-counterfeiting products, as well as brand protection. Amongst other things, his company prints money, and produces passports, and ID cards, chipped or otherwise. Getting power into paper for a display is tricky as power sources are large, and things have to last long time, passports for ten years, for example. So what about energy harvesting? Harvesting energy from a mobile phone is a possibility, by rectifying the AC output into DC power, so the need is to develop a printed rectifier capable of powering overt displays that switch in a second. Here, Acreo AB and Dr Geran Gustavsson became involved. They needed rectification up to 2.4 GHz, which meant a Schottkey diode. The rectifier needed to be thin (<50 μm), the number of printing steps needed to be low, and at a low processing temperature. Acreo have experience in R2R printing, and they have produced a Si Schottkey diode with lower threshold voltage, sufficient for energy harvesting, up to 2.4 GHz, which is sufficient to light up a display. They produce these by R2R printing, making their own ink, using a Nilpeter system. For the future, they wish to obtain a longer reading distance, but the diodes work, and meet the criteria in that they are printable, and you can rectify mobile phone energy sufficient to light up a display.
Dr Juha Maijala of Stora Enso in Finland had the topic of wireless healthcare solution using printed and conventional electronics. His company, famous for newsprint and paper products, has a turnover of €11 billion. He manages their Intelligent Solutions division, where the basic idea is to create products or clinical trials for paper products used in the pharmaceutical field. They have a wireless DDSi package that tracks one pill at a time and using GSM/GPRS networks delivers data to electronic health record systems. Life is 100 days, and the electronics section of the card can be re-used. The system allows follow-up possibilities toward patients, such as a voice call, SMS, or a personal visit, if medication is not taken. For patients suffering from schizophrenia, Alzheimer’s, or Parkinson’s, where self-medication can be unreliable, this system is effective.
Balance cost of hospitalising a patient at $20,000 per time, against the cost of the package and it make sense. Consumers are unwilling to pay a premium for packaging that just communicates product information, but they would pay more if related to health, convenience, and safety. Further R&D will look at sensors for gas, bacteria, and thereby improving food safety.
Professor Elvira Maria Fortunato is from the Faculty of Science and Technology at the University of Lisbon and specialises in transparent electronics, which have application in the display field. They need high resolution, high brightness, and high data transfer speed, but transparent electronics offer high electrical performance, and have enhanced stability. Oxide thin-film transistors based on an indium gallium zinc oxide system were used, with application by sputtering. They have also replaced the indium with tin, and the TFTs thus produced work well. The results have been excellent overall, passivation brings great improvement in stability and shelf-life is enhanced. It is possible to use these inorganic materials now; they offer a 54 per cent reduction in the cost of PE. High-performance p-type oxide TFTs will promote a new area in flexible electronics, allowing a move away from silicon. The demand for low processing temperatures will motivate the continued research with p- and n-type oxide TFTs, so far they have produced high-performance p-type p-channel oxides on glass which are looking very promising. The work continues under a seventh Framework project.
The University of Technology in Chemnitz houses the Institute for Print and Media Technology, whose Professor Arved Hubler presented the case for printed solar cells on paper – the why and the how. He saw the need for mass printing of electronics, in the billions, and for a real added value; here the mass would be photovoltaics; energy is seriously needed in various conditions, and if it really works a demand will be there.
They have used traditional material, PCBM in a sandwich with electrodes, one of which is transparent, and a PEDOT anode for conductivity, all on a base of paper. No clean room is needed, only standard equipment; it is a low cost, simple application with easy recycling. The investment level is low, and they have proved that it can be done, and if a paper PV sheets needs replacement, then this is an inexpensive operation. Sure the process needs some optimisation, but overall it works. They claim a lifetime of 100 days, with the paper PVs offering full recycling. It is cheap, and in reality can be produced by anyone anywhere. From the delegates came a number of questions about moisture ingress? UV barriers might be possible. The next research fields would be looking at increasing efficiency, optimising the processes, and at life time, humidity, UV exposure, mechanical stability, as well as the merits of paper v foil, amongst others.
Dr Carl Taussig from Hewlett Packard presented a paper on roll-to-roll manufacturing of displays on plastic substrates using self-aligned imprint lithography (SAIL); recent developments. HP started on R2R five years ago, and decided upon imprint lithography, for better resolution, for which the system relies on the UV curable imprint. The technique comprises the vacuum deposition of the TFT stack on the substrate, then coat with polymer, emboss, cure with UV, release, and etch. The line runs at 5 m/m, with high-feature resolution, and the system self-aligns as the mask distorts with the substrate. SAIL offers substantial savings in comparison with normal photolithography. They have a flexible OLED display approach as well; OLEDs are great but there are queries on lifetime, colour stability, and material compatibly. They can now laminate the OLEDs to give longer life, and they are also working with SAIL backplanes with multicomponent oxide TFTs, which increase semiconductor performance 10xs whilst reducing the number of process steps by 25 per cent. As an example of what can be produced with this technology, Carl demonstrated the wonderfully named “Dick Tracy” watch for the US Army, a wrist-worn display that is very tough, solar powered, has a display in b/w with text and maps, and is powered by an integrated flexible solar cell.
The R&D team leader at Applied Materials GmbH in Germany is Dr Neil Morrison who is working on silicon-based flexible TFT device technologies. There is quite a wide variety, used for displays, energy, etc. but PVs, batteries, and touch screens are all now mature products and are out in the market. Such flexible electronics are best supported by being low cost. The cost per function is important, so R2R processing is attractive, as it handles substrates that are kms in length, with widths up to 1.4 m. It is an in-line coating process, and has an in-line monitoring and control necessary to maximise productivity. Production speed is 0.5-10.0 m/m depending upon layer stacks. Substrates need to be low Tg, have a high CTE, and as they tend to have high levels of water absorption, need a barrier coating. Polyimide is the best substrate so far. They have a Smartweb, well suited to flexible electronics, for flexible TF-Si process integration.
Dr Andrew Flewitt from Cambridge University came to talk about metal oxide sputtering at low temperatures. How do they fit? They fit everything from semiconductors to dielectrics. This is a room temperature process, where the substrate is amorphous silicon, a well-known material; it is stable, non-toxic, it tolerates low-temperature processing, but it has low carrier mobility, it is metastable, and there are patterning costs. Dr Flewitt made a thoroughly comprehensive presentation that would be of interest to those familiar with the application of silicon dioxide as a dielectric, and with hafnium oxide as a semiconductor.
High Density Printed Memory was the heading, under which a paper entitled The path to integrated devices came from Dr Davor Sutija of Thinfilm Electronics in Norway. He thinks that PE will change our lives, and that it will be in high volume in many different applications. However, one area that has little focus is memory. His company has proven that 2-bit memory (a tag) can be produced in high volume on a R2R system, and used everywhere. You can store rewritable memory anywhere, and stored memory can be added to any smart systems and devices. Tagging has two faces, one is to tell you all about the object, and the other is to identify it. WalMart plan to RFID tag all men’s clothing, which will need 2,540 million tags. The Royal Jordanian Government plans to tag all artefacts in their country, for example, and with a mobile phone you can call down all the information from Google. Open up PE to the consumer market and then you have the volumes you need. This rewritable tag can change the way we do retailing in the coming years, as polymeric memory replaces flash memory. The cost of producing is per mm2 and if you can make a memory cheap enough, you can bypass Si. Polymeric RFIDs will have a unique cost advantage. Printed tags have a cost potential well below the integration costs of silicon chips. NFC-enabled phones able to read RF tags are coming. Working with PARC, they can now offer a tag of thin-film memory up to 128 bits. Proximity ID tags, price displays, NFC RFID will be another direction. The ID market boom has started, with thin film uniquely positioned with low power rewritable memory that meets the standards.
Professor Margit Harting of the University of Cape Town came to speak in the most engaging way about printed silicon technology. But you cannot print silicon? Can you? Yes, you can, said Margit. It is very simple. Taking some nanoparticles down to 60 nm, they mix them with some silicon ink, and they screen print on any substrate. They make temperature sensors called thermistors, which decrease in resistance as the temperature increases. They can be printed, and they can measure temperature from −40°C to +120°C. Their sensors can be used to measure area, and volume, and over large areas.
The n- and p-type nanoparticles are milled from bulk Si, and this small size eliminates the oxide layer normally seen between si particles, and with the resulting ink they can screen print 50 μm lines with 100 um gaps using water-based inks with good uniformity in solid areas. Printing has to be done so that there is a charge transport or link through the particle network. Other applications include touch switches and proximity switches, and she engagingly demonstrated how everything worked.
Dr Volker Zoellmer from Fraunhofer IFAM presented a paper entitled “InkTelligent printing of sensor structures” which was most apt. Amongst the 60 Fraunhofer institutes all over Germany, his division specialises in printing, in all forms. From design and layout, material screening, printing, and processing, they cover all aspects of production. He introduced us to aerosol printing, which uses ink at a much higher viscosity than inkjet, and with aerosol you can print a track on a human hair, so, yes, the definitions are fine.
Metallic alloy inks have been formulated, such as CuNi, and after printing sintering takes place, by such methods can strain gauges be printed, and mechanical tests showed no significant changes. Bio printing was described, using a protein to create sensors. A method substitution wire bonding was illustrated; the direct write of conductive contacts was used. Finally, the rapid prototyping of hetero-integrated modules using CuNi ink on non-conformal surfaces. Sintering takes place in an oven. By combining ink-jet and aerosol printing, they could now print capacitors.
Mr Laurent Jamet is the Director of Business Development at ISORG in France.
This is a start-up company in electronics, presenting new features to the market. Based in Grenoble, they are a spin-off from CEA Grenoble Nanomaterials Laboratoire. Organic photonics was the subject under discussion; by transferring glass and plastic into a “smart” surface that can see, i.e. it becomes an image sensor. By transferring R&D into products, they are confident of striking it rich in the consumer market. They enjoy strong links with suppliers, and a pilot line will be completed by the end of this year. How the image sensor was formed was described and explained. Flexible, thin, transparent and robust, their sensors have been used in industrial process control, in the pharmaceutical and biotech industries, in the food industry, and semiconductor and display industry, although to a lesser extent.
Professor Emil List is the Scientific Director at NanoTecCentre in Wiez, Austria. His production company is entitled Isotec, who make sensor devices for application in the field of integrated organic sensors and RF tags. They can be used in the medical field, detecting electrical signals. Overall, the professor prefers ink-jet printing, and if one could achieve an output of 1,000 m2 per hour this would produce all the devices we would ever need! Inkjet has a low investment barrier, it is direct write technology, and the development of inkjet he thinks is protracted, and although ink-jet printed nanocrystal photo-detectors are operating at up to 3 μm wavelengths, optimising ink-jet printing for homogenous films is very difficult.
ISIQIRI Interface is also from Austria, and Dr Robert Koeppe introduced us to Q-Foil technology, large area position sensitive photo-detectors. These photo-detectors are based on polycarbonate, which is very smooth, and very transparent, and by using multiple laser beams, can detect images, and the technology lends itself to interactive projection systems (presentations, teaching, marketing, entertainment, games, training, etc.) large touchscreens (digital signage, marketing, entertainment, teaching, training, etc.) as well as safety and security. The technology allows very large screens to be produced for some €5,000.
Looking at PE applied to vehicles, Dr Peter Harrop of IDTechEx said that thin film and PE and electrics are being used more and more in electric vehicles, as traction batteries, super capacitors, supercabatteries, photovoltaics wide area sensors, harvesting movement, e.g. piezoelectrics, are replacing conventional control/ lighting clusters and are used in wireless sensors and actuators. The present generation of lithium-ion traction battery will give way to batteries with less cobalt or no cobalt cathode, and will be more stable, eventually we shall see lithium sulphur or lithium air. There will be fully solid-state thin films, usually inorganic. In ten years time, 15-20 per cent of cars will be electric and this will be a $60 billion business. The Indians, who own Jaguar/Land Rover are being very strategic, and are investing £50 million in electric vehicles in the UK. Fuel cells using thin film and printed technology. In the future, there will be aircraft having electric wheels for taxiing. Peter illustrated a CIGS PV powered surveillance airship with hydrogen which could stay airborne for ten years, and a submersible that could surface for recharging from solar and wave power before submersing once again. There are some fascinating PV projects such as a bullet train powered by solar cells along the tracks, and a drone called Com-BAT which would be solar powered.
Summary – the move from Dresden to Dusseldorf is entirely understandable. This annual event has grown from one room in Cambridge to an international event for over 1,000 delegates, with 87 exhibitors in the Congress Hall in Dusseldorf. That is has done so is largely due to the fact that, whilst the PE industry has been growing, it is an organisation such as IDTechEX that has brought this into public focus and attention. Not only that, but they have the gift of being able to plan and organise an event of this ilk with great skill and accomplishment, and it would be hard to imagine any better partner for an industry that has yet to come of age.
John LingAssociate Editor