In recent years, more and more industrial products use capacitive touch technology, which further enhances the user experience between people and machines. Automobiles, home appliances and office equipment have taken the lead in using this technology. Capacitive touch membrane switches make products more fashionable, simpler, more durable and cost-effective.

1. Introduction

Capacitive touch membrane switch, also known as capacitive membrane switch or capacitive sensor, works by detecting changes in capacitance caused by finger touch. This technology moves away from mechanical button switches, and eliminates failures caused by mechanical wear.

This kind of membrane switch can be made very thin. The thicknesses is typically between 0.10 and 0.50mm. It is flexible, and can be used in applications with different shapes or curved surfaces.

Capacitive membrane switch has high transparency in graphic area, allowing backlight from the bottom circuit to pass through the plastic graphic. The capacitive touch film is applied to the back of the user interface. The film is usually a glass or plastic cover with a graphic icon or switch.

2. Features

Good look

Capacitive touch membrane switch becomes popular. It can bring an overall improvement in the appearance of the product. It has a smooth surface and no protruding keys. Through the transparent conductive film, the lighting function can be easily realized.

Simple structure

The structure is simple, with a maximum of three layers. The thickness can be flexibly controlled. It can be thinner than traditional membrane switch. Its flexibility enables it to be combined with curved products.

Safety

There is no need for human body to directly contact the metal, which can completely eliminate safety hazards. It can be used even with gloves, and is not affected by dry or humid weather, changes in human body resistance, etc., making it easy to use.

The sensing part can be placed behind any insulating layer (usually glass or plastic material), making it easy to make a keyboard sealed from the surrounding environment.

Long service life

There are no mechanical parts like in traditional membrane switches, capacitive touch membrane switch is virtually free of wear, extending their lifespan. This reduces future maintenance costs.

High sensitivity, low resistance

The touch sensing execution time (sensitivity) can be freely adjusted according to requirements. The circuit is highly precise. The minimum lead spacing can be 0.5mm. The resistance is extremely low. It is easy and quick to use.

Wide applications

It can be widely used in industrial control switches, instrument control panels, washing machine control panels, smart access control system control panels, home appliance membrane switches, etc..

3. Raw materials

Indium Tin Oxide (ITO)

Indium tin oxide is new, and it's good. With magnetron sputtering technology, people use ITO material as a sputtering target, sputtering an indium tin oxide conductive film coating on a polyester film, and then anneal it at high temperature. ITO conductive film is a metal compound with good transparent conductivity.

The circuit is presented through silkscreen printing and etching technology, thus make transparent conductivity come true. ITO transparent electrode has high transmittance and low resistance, making it an excellent choice for products with high display requirements.

PEDOT

PEDOT offers an economical alternative. As an alternative to ITO, PEDOT sensors have been shown to withstand more than 5000 bending cycles. PEDOT also offers a more cost-effective solution.

PEDOT is printed on polyester film through silkscreen printing. It can replace indium tin oxide (ITO). PEDOT is widely used in capacitive touch membrane switches. The thickness of printed film is usually within 1um.