폴더블 키보드용 FSR잉크의 개발

Abstract

Miniaturization and increase on penetration rate of Smart Device replaced the role of computer or laptop that people use smart phone or tablet instead. However, there are limits on performance for tablet and smart phone, which are emphasized on portability, to conduct; lack of accuracy and speed of virtual keyboard. Consequently, more and more people use Bluetooth keyboard as an alternative. PCB etching method is utilized to product Bluetooth keyboard at the moment, but this method consumes more time and money compare to printing method. Especially, copper etching produce massive amount of pollutant that cause difficulties on waste management. With the reasons above, PCB manufacture utilized printed electronics technology is highly prominent in the industry. When applying printed electronics technology on the production process, cleaner production and simplification of the process are plausible that bring the cost down. For example, there are more than 8 processes to form a gate electrode on TFT (thin film transistor) production and 40 or more process to produce one TFT. When we apply printed electronics technology, there are only 4 processes for it, 10 times fewer. We conducted this study as categorizing types of resin and content of resin of carbon paste for FSR(Force Sensing Resistor) sensor that utilized screen print method on production. We utilized two different types of resin and selected 2 resins with different molecular weight for each kind. We aimed for carbon paste with high adhesive strength and hardness and steady conductivity. We drew that paste with 10,000∼30,000 cps on viscosity, adhesive strength that would not be removable on cross-cutting test, over 3H on hardness, and 18.0~27.0 Ω⋅㎝ on conductivity are most appropriate. Based on this, we tried to find best resin and the content. Epoxy resin FPE-50, bisphenol A polymer, are selected as the most suitable candidate through the first test, comparison on type of resin, and the most suitable content are confirmed as 21.51% via the second test, comparison on content of resin.