What are the Types of Capacitive Touch Switches?

Capacitive Touch Switch

In the field of capacitive touch switches, a variety of materials and technologies demonstrate their unique characteristics and advantages. These include traditional solutions like springs and conductive foam, as well as more advanced technologies such as FPC (Flexible Printed Circuits) and PET (Polyethylene Terephthalate) films, especially when employing materials like ITO (Indium Tin Oxide) and PEDOT (Poly(3,4-ethylenedioxythiophene)) on PET films.

Application of Springs in Capacitive Touch Switches

Typically, springs are combined with capacitive touch electrodes on PCBs (Printed Circuit Boards). One end of the spring is soldered to the capacitive touch electrode on the PCB, while the other end contacts the graphical interface panel. This method offers a unique and effective solution, particularly suitable for products with sufficient internal space. Spring-based capacitive touch buttons are economically beneficial, but they may not meet the requirements for more demanding products, such as waterproof design and noise control.

Use of Conductive Foam in Capacitive Touch Switches

Conductive foam, similar to springs in function, is also integrated with PCBs. It’s a material known for good compressibility and conductivity, placed at the PCB touch electrode location and contacting the graphical interface panel. However, like springs, its drawbacks limit its application to lower-end market products.

FPC in Capacitive Touch Switches

FPC, or Flexible Printed Circuit, is a thin, soft, and bendable circuit board material. It offers a highly flexible way to create complex circuit layouts for capacitive touch switches. FPCs can be designed in precise patterns to form the sensitive areas of touch switches, enhancing design flexibility and adapting to various shapes and sizes. However, FPCs typically lack transparency in the touch electrode areas and are relatively costly, thus they’re used in specialized products. Notably, the WeGlow team has overcome the issue of FPC transparency in capacitive touch buttons, offering customized FPC touch solutions.

PET Films in Capacitive Touch Switches

PET films, widely used in capacitive touch applications, come in two types: ITO and PEDOT.

1. ITO Films: ITO, an Indium Tin Oxide layer, is deposited on PET films through a vacuum plating process. The non-conductive parts are removed through etching, and silver paste is printed in contact with the ITO layer. ITO is commonly used in products requiring high transparency.
2. PEDOT: PEDOT is a conductive polymer that, due to its cost advantage over ITO, is widely used in capacitive touch fields. PEDOT is screen-printed onto films, and conductive silver paste is printed to make contact with it. For more information about PEDOT, please read ”What is the PEDOT that is used for capacitive touch switch?“

ITO and PEDOT offer revolutionary solutions in the field of capacitive touch, fulfilling functional needs while providing significant advantages in design flexibility and cost-effectiveness.

The article ‘ITO Film vs. PEDOT Ink: Which is the Best Solution for Capacitive Touch Switches?’ will help you choose the right solution for yourself.