Arto Maaninen

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.

Spectroscopic studies of a ring opening process between epoxy- and aminosilanes and imine formation reactions in aqueous solutions

AbstractNMR and Raman spectroscopy studies were performed for different 3-aminopropyl(trimethoxy)- and 3-glycidoxypropyl(trimethoxy)silane based sol-gel systems containing different ketones. Exceptionally stable imine products were obtained depending on a reaction system at alkaline pH conditions and in the presence of water. These imine formation reactions were carried out without further catalyst. In addition, effect of water for the epoxy ring opening process was demonstrated, as well as the effect of solvents for the reaction path was confirmed. The reaction between 3-aminopropyl(trimethoxy)- and 3-glycidoxypropyl(trimethoxy)silane needs additional catalyst to proceed fast or the reaction between the organic parts remains very slow. In case of isopropyl alcohol as the solvent, the result is the same. Water catalyses the organic and hydrolysation/condensation reactions. Ketones, like acetone initiates stable imine formation and water as a by-product methoxy group hydrolysation, but the epoxy groups remains unchanged after long periodHighlightsStable organosiloxane based imines were synthesised in the presence of water as a by-product and in a very alkaline conditions (pH ≥ 12).Synthesised and characterised amine/epoxy/ketone – sol-gel one-pot systems proved that ketones and amines form imines, as was expected, and these imines showed to be very stable in aqueous solutions and no drying agents, extraction or precursors having aromatic substituents were used during the syntheses.

Photo-crosslinkable hybrid material with improved aging stability for integrated optics

In the last decade, the processing of the waveguide structures on various substrates under mild conditions has been an appealing aim. The lithographic patterning of organic-inorganic hybrid materials processed by means of sol-gel technology allows the production of waveguides and other optical components. We describe the synthesis of a new, photo-patternable, organically modified material with an improved ageing stability. Synthesis step does not involve widely used zirconia precursors, but it retains the same possibility of altering the refractive index by tailoring of the material composition. Refractive index values varied from 1.4700 to 1.5100. Measured birefringence values meet the requirements of most integrated planar optic applications. The synthesized material is compatible with silicon, glass and plastic substrates. Material was analyzed using 29Si NMR techniques. The processed slab waveguides were characterized by using the prism coupling technique at various wavelengths. The attenuation in the waveguide was determined by the cut-back method, and it was found to be less than 0.5dB/cm at the wavelength of 830 nm. The morphology of the microstructures was measured by using the interferometer equipment. Slab waveguides rms values were in order of only 2 nm.