Harri Kopola

Towards roll-to-roll fabrication of electronics, optics and optoelectronics for smart and intelligent packaging

Embedding of optoelectrical, optical, and electrical functionalities into low-cost products like packages and printed matter can be used to increase their information content. These functionalities make also possible the realization of new type of entertaining, impressive or guiding effects on the product packages and printed matter. For these purposes, components like displays, photodetectors, light sources, solar cells, battery elements, diffractive optical elements, lightguides, electrical conductors, resistors, transistors, switching elements etc. and their integration to functional modules are required. Additionally, the price of the components for low-end products has to be in cent scale or preferably below that. Therefore, new, cost-effective, and volume scale capable manufacturing techniques are required. Recent developments of liquid-phase processable electrical and optical polymeric, inorganic, and hybrid materials - inks - have made it possible to fabricate functional electrical, optical and optoelectrical components by conventional roll-to-roll techniques such as gravure printing, embossing, digital printing, offset, and screen printing on flexible paper and plastic like substrates. In this paper, we show our current achievements in the field of roll-to-roll fabricated, optics, electronics and optoelectronics. With few examples, we also demonstrate the printing and hot-embossing capabilities of table scale printing machines and VTT Electronics PICO roll-to-roll pilot production facility.

Micro Roll-to-Roll Patterning Process and Its Application on Flexible Display

Novel electrode patterning techniques on thin polymer substrates were developed on a roll-to-roll (reel-to-reel, R2R) printing system. Hot embossing, laser ablation, and lift-off processes were evaluated for mass production for active-matrix display arrays with 1000 µm display pixels by using the concept of micro electro mechanical system (MEMS) Fabry–Perot etalon. Among which, the newly developed lift-off flexography process provided the best pattern integrity with 100 µm resolution. The demonstrator of display array proved R2R printing systems possibility and capability under 1 m/s speed. A complete multilayer stack demonstration with alignment process also indicated its variable application. Further actuation for the MEMS display proved the robustness of device made by printing techniques.

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.

Low operation voltage non self-emissive MEMS color filter pixels

A 50% reduction of operation voltage improvement was achieved on a non self-emissive color filter pixels based on MEMS (micro electro mechanical system) Fabry-Perot interference device by minimizing its Newtons rings size. Newly designed air grooves in spacer layer were proved to be efficient to evacuate air trapped inside pixels which in turn effectively lowered its operation voltage. A seesaw effect was also found if air groove occupied too large area which degrades the operation voltage lowering benefit.

Bioactive hybrid materials for photonic microsysterns

Bioactive hybrid materials have been produced by the sol-gel method. Antibodies used in this work retained their activity after doping and processing. The developed materials can be used e.g. for optical MEMS applications in diagnostics

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