Key button structure for handheld mobile phone and its similar instrument, and method for forming the same

Abstract

A key button switch structure for use in a handheld mobile phone, comprises an input button 1 having a push-down pressure transmitting projection A1 and a button inclination preventing projection B 3 both projected from a bottom surface of the input button, integrally with the input button. Two electrodes A9 and B 10 are formed on a substrate 8 fixed to a body casing 6. A dome-like switch contact 7 is provided to be pushed down by the push-down pressure transmitting projection A1 of the input button when the input button is depressed, thereby to electrically contact both the two electrodes. Thus, since the button inclination preventing projection B 3 is provided, even in the case that an action center line of the dome-like switch contact is not coincident with an input pressure center line of the input button, when the input button is depressed, the electrodes A9 and B 10 formed on the substrate 8 are surely electrically interconnected by the dome-like switch contact effectively uniformly collapsed by the push-down pressure transmitting projection A1 of the input button.

Dependencies are inferred from the claim text.