Abstract: A key signal-generating device has a thin film circuit board to generate key signals and a plurality of hollow rubber domes set on the thin film circuit board that are compressed by their corresponding keys to activate the thin film circuit board to generate corresponding signals. The rubber domes have a predetermined space that is filled with air. The thin film circuit board has a top surface and a trench on the top surface. One end of the trench extends into the predetermined space so that the predetermined space is in communication with the atmosphere. When a key is pressed, the corresponding rubber dome is squeezedby the key, causing the air in the predetermined space to exit out to the atmosphere through the trench.

Abstract: A key signal-generating device has a thin film circuit board to generate key signals and a plurality of hollow rubber domes set on the thin film circuit board that are compressed by their corresponding keys to activate the thin film circuit board to generate corresponding signals. The rubber domes have a predetermined space that is filled with air. The thin film circuit board has a top surface and a trench on the top surface. One end of the trench extends into the predetermined space so that the predetermined space is in communication with the atmosphere. When a key is pressed, the corresponding rubber dome is squeezed by the key, causing the air in the predetermined space to exit out to the atmosphere through the trench.