Label:Membrane Switches
Jan 10, 20245800
There is a wide range of application for membrane switches. The structure and producing process of them are different according to the user group, environment and terminal equipment. Let’s talk about some common types of membrane switches.
1. Metal dome
This type of membrane switch uses metal dome as the conductive medium.
Pros
Good feel of keys, even force and high stroke accuracy;
Crisp sounds during operation, and you can clearly know the operation status, avoiding repeated actions due to the buffering time of some equipment;
The operating temperature can reach -20 ~ 80℃.
Cons
When the liner is uneven or pasted at an excessively large bend, the spring fragments may cause short circuits, malfunctions, and non-rebound.
Note: Put this membrane switch on a flat liner that can withstand the force of the keys, or directly use a thickened PCB as the circuit layer.
2. Die pressing ( keys type)
It is an embossed silver pad in the circuit layer by the "embossing" process, the silver pad of the button as the upper circuit is pressed into a fixed spherical crown shape with a mold.
Pros
Long service life of more than 500000 times pressing;
Good handfeel, and the stroke and strength can be customized according to customer needs;
Cons
High mold cost, and convex mold is required;
High temperature may cause the key force to weaken.
Note: Use hardware mold for the convex mold to ensure the consistency of the button strength and stroke.
3. Flat keys (no embossing)
The contact points use film substrates printed conductors. There is no secondary processes.
Pros
The keys have long service life of one million times pressing;
Large conductive contact area to ensure conduction rate.
Cons
There is no operating feel, and it is easy to cause repeated actions or misoperations.
Note: Enlarge the distance between keys as much as possible. Otherwise, the failure rate will increase and the lifespan will be reduced.
4. Capacitive induction type
It uses conductors to induce conduction.
Pros
It can sense motion within a certain distance like a capacitive touch screen;
The sensing distance can be designed according to customer specifications.
Cons
The qualification rate of finished products is low. It is allergic to surrounding electromagnetic interference, and the design requirements are very high.
Relevant electronic components and chip support are required.
5. LED light guide plate type
It is made based on the ordinary membrane switch, the built-in light guide plate allows the product to work in places with insufficient lighting.
Pros
The product is high-end and elegant. The light part can be customized according to customer needs;
It can work in places with insufficient light;
Colors can be customized according to customer requirements. Blue, red, orange, white, and green are popular.
Cons
Due to the existence of light guide plate, this type of membrane switch is thicker. Generally, the thickness is 2.5-3.5mm.
6. EL cold light type
EL cold light source is embedded in the conventional membrane switch.
Pros
Compared with the LED light guide plate type, the thickness is greatly reduced. Overall, it's 1.5-2mm;
The cold light source is suitable for the normally on state, without taking into account the heating problem;
The luminous area and color can be customized according to customer needs.
Cons
Cold light sources need to be equipped with drivers.
7. PCB type
PCB replaces the conventional membrane switch.
Pros
The circuit has high precision. The welded LED is stronger and more reliable, and the resistance value is low;
The thickened PCB layer can be used directly as a lining board.
Cons
PCB is rigid, it cannot be bent.
8. FPC type
The circuit layer of the membrane switch adopts FPC (flexible printed circuit).
Pros
FPC has high precision. The welded LED is more solid and reliable, and the resistance value is low;
It can be as resistant to bending as film printed circuits.
Cons
The cost is high. It requires large quantity.
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