Investigation and improvement of atomization efficiency based on SAW device coated with amorphous fluoropolymer film for olfactory display

This paper reports on a method to realize the instant and high-efficiency atomization for liquid perfumes in an olfactory display system using surface acoustic wave device coated with amorphous fluoropolymer film. The liquid perfumes diluted with ethanol tend to spread into a thin film on LiNbO3 substrate before atomization, which causes low atomization efficiency and serious smell persistence. The proposed method employs a layer of 400 nm thick amorphous fluoropolymer film Cytop on SAW substrate to maintain the droplet's sphere-like shape due to the excellent hydrophobicity. Amino-based silane coupling agent was used to enhance the adhesion. The difference of atomization process between hydrophilic and hydrophobic surfaces was clearly revealed. With the finer and more stable mists being generated on coated surface, the significant improvement of atomization efficiency was demonstrated. Sensory test results on three liquid perfumes show that the smell persistence was greatly reduced after the coating.