Membrane Switch

Shanben offers custom membrane switch solution within 72 hours.

Basics of Membrane Switch: Structure and Material

There are two main structures:

Raised structure:

The switch button is slightly raised, slightly higher than the panel, forming a 3D membrane switch. The convex is helpful to stimulate the operator’s sensitive touch, so as to help the operator accurately determine the position of the button and improve the recognition speed. The convex of the membrane switch can be designed into a variety, improving the decorative effect of the product and achieving a perfect appearance.

Flat structure:

Flat structure was common in the initial stage of membrane switch. The buttons on the membrane switch simply use color to express position, shape and size. The accuracy of the operation can only be identified by the operator’s vision, and there is no appropriate feedback information to indicate whether the fingers press the effective range of the switch to make it work, thus affecting the confidence of the whole machine monitoring and control, and the speed of operation as well.
There are three main materials used for membrane switch:
Material: Polycarbonate (PC) 

Advantage:
Temperature resistance – 60 ~ 120 ℃, thickness 0.125 ~ 1.2, smooth surface, high transmittance, environmental protection, low water absorption, good dimensional stability, excellent bending, tensile and compressive strength, excellent heat resistance, cold resistance, electrical insulation and atmospheric aging resistance. It can meet the requirements of most membrane switch panels, and the high transmittance of PC can meet the requirements of LCD window.
Disadvantage:
Chemical resistance (organic solvent) is poor, fatigue resistance is poor, stress cracking is easy to occur, air oxidation is easy to gradually form a falling off layer, determined by the environment, and finally gradually decomposed. The physical damage time is 3-8 years.

Material:Polyester (poly (ethylene phthalate) (PET)

Advantage:
Temperature resistance – 30 ~ 160 ℃ / thickness 0.075 ~ 0.25/smooth, good drug resistance.
It has excellent mechanical properties, insulation, heat resistance, hardness and the largest strength and toughness of thermoplastic, excellent wear resistance and friction resistance, especially with bending resistance and high elasticity, and high dimensional stability.
The tensile strength is comparable to that of aluminum film, much higher than that of PC and PVC. It is the most ideal substrate for making thin film switch circuit. Textured pet is the preferred material for membrane switch panel.
Disadvantage:
Insoluble in general organic solvents, not alkali resistant.
Low water absorption.
Textured pet is expensive.

Material:Polyvinyl chloride (PVC)
Advantage:

Temperature resistance -20~60 ℃ / thickness 0.175~1.5/ smooth surface, stable to acid, alkali and salt under normal temperature. It has good wear resistance, flame resistance and self extinguishing, noise elimination and shock absorption, and good electrical insulation.
Disadvantage:
Poor thermal stability.

Membrane Switch Product Categories

According to their main characteristics, Shanben’s core products are classified as follows. All are able to be customerized as per customers’ specific demands.

1. Flat light-touch type

Main feature: no secondary process adopted for the contact surface
Advantages: service life over 2 million times, with large contact area
Disadvantages: monotonous, easy to cause misoperation
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2. Light guide plate type

Main feature: light guide plate embedded in conventional membrane switch
Advantages: able to operate with insufficient light; nice looking at lower cost than EL type
Disadvantages: high thickness, suitable ONLY for embedded fixed mode
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3. FPC type

Main features: flexible circuit board used for the circuit layer
Advantages: high precision circuit, min. wire distance 0.5mm, low resistance value, able to weld small components like LED, resistance and optical fiber, reliable and long service life. outperforming the general silver slurry type
Disadvantages: high cost
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4. Metal shrapnel type

Main feature: shrapnel as the key contact surface of the upper circuit

Advantages: 
a) good handle and even strength 
b) Operation accompanied by clear sound
c) High temp resistance
Disadvantages: vulnerable to damage caused by bumpy lining plate or too large bending arc, resulting in short circuit or non rebound; no secondary assembly
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5.Hot pressing type

Main feature: the key uses PET material to print the contact surface, and then it is embossed to form resilience
Advantages: service life over 1 million, with good hand feeling
Disadvantages: the touch of keys may be weakened by high temperature 

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6. PCB type

Main features: PCB (hard circuit board) used for the circuit layer
Advantages: small resistance, precise circuit,able to be directly welded on the back of some components in the circuit
Disadvantages: not as convenient as the flexible switch in the whole machine assembly, needing for welding the connector and leading out thru flat cable
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7. LED light type

Main features: LED lights are assembled in a membrane switch as a whole
Advantages: (a) the LED line and the lower line are on the same layer: the structure is simple, but the LED window should be convex, otherwise, the LED light will jack up the panel; it is suitable to select small LED lights with low height or occasions with small number of LED lights; 
(b) Different layers of LED lines and lower lines: the structure is complex, but the LED window does not have to be convex, which is suitable for the occasions with more LED lights; punching die and bottom rubber die need to be opened.
Disadvantages: vulnerable to heavy pressure damage, and difficult to recover
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