Membrane switch, also known as touch keyboard, adopts an overall sealed structure composed of multiple layers of planes. It is a new type of electronic component that integrates optics, machinery and electricity, sealing the key switch, panel, mark, symbol display and lining together. Next, we will explain the structure of membrane switch to you.
1. Panel layer
The panel layer is generally a colorless and light-transmitting sheet of less than 0.25MM such as PET and PC with exquisite patterns and texts printed on it. Because the main function of the panel layer is to play the role of marking and button, the selected material must have high transparency. , high ink adhesion, high elasticity, high toughness and other characteristics.
2. Surface adhesive layer
The main function of the surface adhesive is to tightly connect the panel layer and the circuit layer to achieve a sealed connection. This layer is generally required to be between 0.05-0.15MM thick and have high viscosity and anti-aging properties; special membrane switch double-sided adhesive is generally used in production. Some membrane switches need to be waterproof and high temperature resistant. Therefore, the surface adhesive must also use materials with different properties according to needs.
3. Upper and lower layers of the control circuit
This layer uses high-performance polyester film (PET) as the carrier of the switch circuit pattern, and uses a special process to screen-print conductive silver paste and conductive carbon paste on it to make it conductive. Its thickness is generally within 0.05-0.175MM, and the most common is 0.125MMPET.
4. Interlayer
It is located between the upper circuit and the lower circuit layer, and plays a role in sealing and connecting. Generally, PET double-sided tape is used, and its thickness ranges from 0.05 to 0.2MM; when selecting the material of this layer, the integrity of the product should be fully considered. Thickness, insulation, circuit key package feel and sealing.
5. Adhesive layer
The use of adhesive is closely related to the material to which the membrane switch is attached. Commonly used ones include double-sided adhesive, 3M adhesive, waterproof adhesive, etc.