Membrane switch structure

1、 Panel layer

The panel layer is generally made by silk printing exquisite patterns and words on colorless transparent sheets such as pet and PC less than 0.25mm. Because the main function of the panel layer is to mark and press keys, the selected materials must have the characteristics of high transparency, high ink adhesion, high elasticity and high toughness.

2、 Surface adhesive layer

The main function of surface glue is to closely connect the panel layer with the circuit layer to achieve the effect of sealing and connection. Generally, the thickness of this layer is required to be between 0.05-0.15mm, with high viscosity and anti-aging; In production, special film switch double-sided adhesive tape is generally selected. Some film switches are required to be waterproof and high-temperature proof, so the surface adhesive must also use materials of different properties according to needs.

3、 Upper and lower layers of control circuit

This layer adopts polyester film (PET) with good performance as the carrier of switch circuit graphics, and uses special process silk screen to print conductive silver paste and conductive carbon paste on it to make it have conductive properties. Its thickness is generally within 0.05-0.175mm, and 0.125mm pet is the most common.

4、 Adhesive layer

It is located between the upper circuit and the lower circuit layer and plays the role of sealing and connection. Generally, pet double-sided adhesive is used, and its thickness ranges from 0.05 to 0.2mm; When selecting the material of this layer, the overall thickness, insulation, hand feel and sealing of the circuit key package shall be fully considered.

5、 Back adhesive layer

The use of back glue is closely related to the material of membrane switch. Common double-sided adhesive, 3M adhesive, waterproof adhesive, etc. are often used.