Abstract: Capacitive touch keys are widely used in display panel touch control system of household appliances for their advantages of high accuracy and durability. As the first step of human-computer interaction, the sensitivity and reliability evaluation of touch keys is very important. In order to study the influence of circuit board level structure on touch sensitivity and reliability, based on the principle of capacitive touch, the change of touch effect caused by the difference of metal medium in the top layer (only copper plating and tin plating on the copper surface) was discussed. Finally, through the verification and comparison of different media schemes, it is found that the copper plating scheme has better performance in data sensitivity and stability. Through 8 mm and 3 mm copper rod tests, the frequency of z-value>6 in copper plating scheme is about 65.2%, which is higher than that in copper tin plating scheme (28.8%). Through z -value analysis, it can guide the design and manufacture of touch keys.

Key words: Touch key, Capacitive induction, Panel layer medium, Effect analysis