Markus Tuomikoski

Printed hybrid systems

This paper presents research activities carried out at VTT Technical Research Centre of Finland in the field of hybrid integration of optics, electronics and mechanics. Main focus area in our research is the manufacturing of electronic modules and product structures with printed electronics, film-over-molding and polymer sheet lamination technologies and the goal is in the next generation of smart systems utilizing monolithic polymer packages. The combination of manufacturing technologies such as roll-to-roll -printing, injection molding and traditional component assembly is called Printed Hybrid Systems (PHS). Several demonstrator structures have been made, which show the potential of polymer packaging technology. One demonstrator example is a laminated structure with embedded LED chips. Element thickness is only 0.3mm and the flexible stack of foils can be bent in two directions after assembly process and was shaped curved using heat and pressure. The combination of printed flexible circuit boards and injection molding has also been demonstrated with several functional modules. The demonstrators illustrate the potential of origami electronics, which can be cut and folded to 3D shapes. It shows that several manufacturing process steps can be eliminated by Printed Hybrid Systems technology. The main benefits of this combination are small size, ruggedness and conformality. The devices are ideally suited for medical applications as the sensitive electronic components are well protected inside the plastic and the structures can be cleaned easily due to the fact that they have no joints or seams that can accumulate dirt or bacteria.

Hybrid in-mould integration for novel electrical and optical features in 3D plastic products

Next generation of smart systems in different application areas such as automotive, medical and consumer electronics will utilize various electronic, optical and mechanical functions integrated in plastic product structures. In this study, hybrid in-mould integration of electronic and optoelectronic modules was examined in order to embed novel functionality into polymer matrix. The feasibility to converge the printed electronics, component assembly and injection moulding manufacturing processes was examined by simulations, experimental tests and by realizing three demonstrators: over-moulded optical touch panel, plastic embedded flexible organic light emitting diode (OLED) foil and disposable healthcare sensor with over-moulded flexible printed circuit (FPC) connector. The demonstrators proved that hybrid in-mould integration could be feasible technology enabling seamless integration of optical, electrical and mechanical features into 3D plastic products.

Freeform and flexible electronics manufacturing using R2R printing and hybrid integration techniques

Printed electronics and other large-area roll-roll - compatible processes are opening up the new opportunity for cost-efficient mass manufacturing of electronics among other functionalities, on large-area and flexible substrates such as plastic, paper, metal foils, glass and fabrics. Data processing power and other functionalities still require high performance microelectronics circuits and therefore, also traditional electronic/semiconductor technology are also needed. These needs lead to technical manufacturing requirements that can be fulfilled best with concept of utilization combination of printed electronics and hybrid integration of silicon electronics to flexible printed platforms. Extending the continuous roll-to-roll manufacturing approach as far as possible (in air or/and in vacuum) in the manufacturing process to assembly and bonding, the manual assembly and handling phases can be almost fully eliminated. In this paper recent development to manufacture freeform and flexible electronics components and systems using printing and hybrid integration processes is presented. Production examples of hybrid integration will be presented for 1) LED display, 2) a large area roll-to-roll processed LED luminaire, 3) over-moulded optical touch panel and 4) over-moulded OLED subassembly.

Gravure printed optoelectronic thin films for flexible polymer LEDS and microsystems

Polymer LEDs based on gravure printed light-emitting polymer film were investigated. The printed films achieved flat uniformity over large area given a capability of roll-to-roll manufacturing of optoelectrical thin film components

Indoor air quality sensing indicators

The indoor air quality sensing indicators introduce people to novel concepts necessary for being aware and analysing of the indoor environments and help them to recognise and address indoor environmental quality problems in the building environments and the link to health, comfort and productivity of the occupants.It is known that people spend most of their time indoors, thus healthy air where they live, work and play is very critical. The European Lung Foundation (ELF) has estimated that respiratory illness in Europe costs some EUR 102 billion a year in poor inefficiency and absenteeism from work [1]. In addition, according to US Environmental Protection Agency (EPA), indoor air pollution is ranked as the highest risk to human health among all types of environmental problems [2]. The important factor and indicator for indoor air quality (IAQ) in room environment is the concentration of carbon dioxide (CO2), which is detected and measured in this study. Moreover, light delivered by the indoor air quality sensing indicators guide people to healthy space, which then increase comfort and work performance. Ultimately, wirelessly connected indoor air quality indicators will become an integral part of the Internet-ofThings infrastructure. They will not only produce light. They will form an essential part of the indoor environment quality, providing decoration and serving as context-detecting sensors delivering semantic information, such as wellbeing, to other systems, such as building ventilation. The indoor air quality sensing indicators in this paper utilise low energy radio network operating at Bluetooth Smart waveband in wireless communication. The radio system provides link to a smartphone app. The CO2 sensing is based on an integrated COTS (commercial-offthe-self) sensor platform engine. The system operation is based on a microcontroller which decodes the CO2 sensor signal, and PWM (pulse width modulation) module which controls operations for light output of LED foil. In the first demonstrator, thin film LED foil is based on the green, yellow and red light emitting InGaN bare die LEDs. And in the second demonstrator, it is based on COTS RGB LED components with built in control IC, which allows individual addressable RGB LEDs. Furthermore, the RGB LED foil is injection moulded into thermoplastics to form a product with improved durability and usability. In this paper, the demonstrators as well as VTTs pilot environment - roll-to-roll (R2R) MAXI pilot printing line, Datacon 2200 EVO pick-and-place bonding machine and ENGEL hybrid in-mould integration line - will be presented.

Overview of the EC project FLEXIBILITY: Organic and thin-film ICs up to radio frequencies for multifunctional flexible systems

This paper provides an overview of the research activities within the frame of the European project FLEXIBILITY. The project aims at advancing the competitiveness of Europe in the area of multifunctional, ultra-lightweight, ultra-thin, bendable organic and large area electronics (OLAE). An overview of the technologies available to the consortium is provided, together with details of the performance achieved by the first prototypes. Particular focus is given to the circuit design in technologies compatible with the flexible components and systems. Using a 50 MHz IGZO TFT technology, several circuits have been demonstrated, including a 20 MHz AM demodulator.

Towards User-Driven Cyber-Physical Systems—Strategies to Support User Intervention in Provisioning of Information and Capabilities of Cyber-Physical Systems

The provisioning of information and capabilities of a Cyber-Physical System (CPS) can be performed directly in the CPS or in external applications and services. A Cyber Physical Production System (CPPS) can be seen to be an example of an evolving CPS, where new elements such as machines can be added to produce desired products. Human interaction with the CPPS can be reorganized among users that participate in the constantly evolving production tasks. This all requires solutions that enable the users to affect provisioning of information and capabilities of CPPS in different kinds of tasks. This chapter outlines an example of a user-driven CPPS and strategies for enabling user intervention in the behaviour of cyber-physical systems and in the behaviour of applications and services that are based on cyber-physical systems. In addition, we outline an architecture for user-driven CPSs that offers support for the proposed user intervention strategies.

Intelligent warning sign system utilising printed functionalities and hybrid integration

The direct medical care cost of all hospital treated injuries in the EU is estimated to be at least 78 billion Euros each year. Therefore, significant savings can be achieved in economical and human resources, when amount of injuries are decreased. Intelligent and active warning sign can prevent accidents more effectively than traditional passive graphical warning sign. Intelligent and active warning sign alerts person approaching potentially dangerous spot using both visual and audible warning. In areas without infrastructure, however, intelligent warning sign need to be autonomous. We have manufactured an intelligent and autonomous warning sign prototype utilising printed functionalities and hybrid integration. Our intelligent warning sign system utilises low energy radio network operating at 2.4 GHz ISM waveband in wireless communication. Radio system provides wireless link to other warning signs nearby and up and down gateway to server. In addition, system retains energy harvesting system based on flexible solar cell and bendable Li-Ion battery. Sensing is based on infrared sensor enabling person detection by emitted thermal radiation from 2 meter distance. Microcontroller decodes sensor signal and controls operations for warning signals based on six blinking LEDs and beeping buzzer. LED flexible substrate was PET foil on which conductive traces were printed using Asahi 411AW silver ink. Miniature high brightness 0402 size μSMD LEDs producing up to 50 mcd in ±65° angle were bonded on PET foil using isotropic conductive adhesive, type EPOTEK H20E. Final measures of the prototype were 75 mm × 220 mm with maximum thickness of 20 mm and weight of 58 grams. System assembly with rigid central part and flexible flanges enabled prototype attachment on flat, angulated or curved surfaces. Implemented warning sign system platform offers also possibility to implement other intelligent guiding and sensing information transmission applications in areas lacking connection to grid and wired Internet.

Roll-to-roll manufacturing technologies for flexible MEMS applications

Roll-to-roll fabrication of electrical and optical structures and functional elements on web will be described. Based on the realized components, the potential of the printing techniques for volume-scale MEMS fabrication will be introduced