Explain the Internal Structure of the Membrane Switch in Detail

Membrane switch is a control system that integrates key functions, indicating elements, and instrument panels. It is made of soft materials such as PC, PET, FPC and double-sided tape, and is made by screen printing technology. It is a multi-plane combination and sealed plastic electronics that integrates graphics, buttons, symbol display, conduction and electronic switch functions. 

Ⅰ. Application range of membrane switch

Membrane switches are widely used in electronic communications, industrial control, medical equipment, automotive industry, instrumentation, household appliances, children's toys, military equipment and other industries and fields.

Ⅱ. The material of each part of the common membrane switch

1. Panel layer

The panel layer is generally made of exquisite patterns and text printed on colorless transparent sheet materials such as PET, PC, etc. that do not exceed 0.25MM. Because the panel layer mainly serves as a logo and button, the selected material must have the characteristics of high transparency, high ink adhesion, high elasticity, and high toughness.

2. Surface adhesive layer

The main function of the surface glue is to closely connect the panel layer and the circuit layer to achieve the effect of sealing and connection. The thickness of this layer is generally required to be between 0.05 and 0.15 mm, with high viscosity and anti-aging properties; in production, generally, special membrane switch double-sided adhesive is used. Some membrane switches require waterproof and high temperature resistance, such as waterproof membrane switch. Therefore, the surface adhesive must also use materials of different properties according to needs.

3. The upper and lower layers of the control circuit

This layer uses polyester film (PET) with good performance as the carrier of the membrane switch circuit pattern, and uses a special process to silk-screen conductive silver paste and conductive carbon paste to make it conductive, and its thickness is generally 0.05 - Within 0.175MM, 0.125MM PET is commonly used.

4. Laminated layer

It is located between the upper circuit and the lower circuit layer and functions as a seal and connection. Generally, PET double-sided tape is used, and its thickness ranges from 0.05 to 0.2MM; when choosing this layer of material, the overall product thickness, insulation, feel and tightness of the circuit key package should be fully considered.

5. Adhesive layer on the back

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