The working principle of metal dome membrane switch and the dismantling analysis of common structures

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The metal dome membrane switch is a control system integrating button function, appearance display and instrument panel. Because of its strict structure, beautiful appearance, good sealing, moisture-proof and long service life of keys, it is widely used in electronic communication equipment, electronic measuring instruments, industrial control equipment, medical equipment, automobile industry, smart toys, household appliances, etc. field.

metal dome membrane switch

Metal dome membrane switch can be divided into flat light touch membrane switch, convex button membrane switch, LED backlight membrane switch, waterproof membrane switch and so on from the overall design structure. It is in contact with the PET soft circuit contact below, and after the finger is released, the shrapnel or the upper circuit contact bounces back, the circuit is disconnected, and the circuit triggers a signal command to the motherboard PCB. The metal dome membrane switch has different material levels due to different structures. Generally, for the disassembly and analysis of the structure of defective products, we disassemble them from the surface layer by layer, but for the convenience of description, it is customary to follow the assembly sequence from the bottom to the top. Layer by layer description.

If it is a waterproof metal dome membrane switch, the outer ring from the adhesive is an integral waterproof ring. From the top panel to the bottom adhesive, the middle LED button shrapnel structure is enclosed inside to prevent water from entering the exhaust groove and the FPC outlet. This metal dome membrane switch has a higher waterproof rating.

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