The application of membrane switches has a history of more than 30 years in China. Nowadays, whether it is intelligent consumer electronics products, general durable household appliances, or even children's toys, membrane switches are widely used. The typical structure of a membrane switch is a multi-layer, planar self-locking key switch composed of insulating materials and conductive material layers with certain elasticity. Its manufacturing process mostly uses screen printing to screen print conductive materials on a flexible polyester (PET) film according to pre designed contacts and circuits, and then combines the screen printed circuit film with the screen printed flexible substrate, PCB board or other panel materials. Compared with traditional mechanical switches, membrane switches have the advantages of simple structure, beautiful appearance, excellent environmental resistance, and long service life. Meanwhile, due to the unique structural form of membrane switches, it is more conducive to the development of electronic devices towards lightweight, thin, short, small, and highly intelligent directions.

Function and application scope of membrane switch

The membrane switch is neither a single new panel nor a single switching element, but a new electronic device based on the working principle of membrane pressure sensors. It can be integrated into the entire machine panel or used as a functional marker; It can be used as an exterior decoration and also as a simple switch button. With the core of thin film pressure sensors, without selecting substrate materials, it can achieve many different functions. Nowadays, it can be seen in various fields such as household appliances, 3C electronics, automotive control, etc. So, it is appropriate for people to refer to membrane switches as the assembly of electronic products that integrate functionality and decoration for operation.

As a novel electronic device, although the application and popularization of thin film switches have been around since the 1980s, with the advancement of technology and the development and application of new materials, their use has spread to various fields such as industry, agriculture, national defense, scientific research, medical care, office automation, household appliances, children's toys, etc. Especially after entering the 21st century, the booming 3C consumer electronics market has driven the continuous development of thin film switches towards miniaturization, intelligence, and multifunctionality. The application of membrane switches in some electronic products can be seen in the following figure:

Technical principle of membrane switch

The membrane switch is actually a set of point touch switches that only transmit operation instructions to the rear circuit of the whole machine. Under normal circumstances, due to the gap determined by the thickness of the window isolation layer in the membrane switch, the contacts of the upper and lower circuits are separated (even in a single-layer circuit structure, the circuit contacts are also separated in a maze like manner). When an external force is applied to a certain function button on the panel to reach the response point, the two contacts corresponding to the button are instantly closed. At the same time, the signal is transmitted to the rear circuit through the connector connected to the whole machine, so that the whole machine works according to the predetermined instructions. After removing the external force, due to the elasticity of the membrane switch substrate, the contacts quickly separate and reset. At this point, the input of a signal has been established, and the overall working state of the machine is not affected by the separation of contacts.

Development of new functions for membrane switches

In the past, we could often see the following interpretation in the external promotion and technical performance parameters of membrane switches: "Membrane switches are only suitable for use in working environments with voltages below DC30V and currents less than 100mA. Literally speaking, membrane switches are only suitable for weak electrical environments, and it seems that membrane switches have lost their usefulness in strong electrical environments. However, nowadays in many high-voltage applications, especially in durable smart home appliances, membrane switches have emerged one after another. For example, Panasonic fully automatic washing machine; Haier washing machine; Haier cabinet air conditioner; Hisense Super Variable Frequency Air Conditioner; The membrane switches on the control panels and remote controllers of Haier, Midea, and Gree electric fans are all prominently displayed. It has been proven that membrane switches are not only suitable for weak current environments, but also play an important role in the field of strong current.

In addition to its application in the field of strong electricity, membrane switches also have another major feature of being able to control multiple functions with a single switch button. For example, on Gree electric fans, a wind type selection button can control the selection of three modes: natural wind, sleep wind, and normal wind; On Haier washing machines, a standard water usage button actually controls 10 functions (ten types of water intake control); This phenomenon also occurs in some consumer electronics products, typical representatives of which are new century fashion appliances such as TWS earphones, electronic pens, and electric toothbrushes. This is another major advantage based on thin film pressure sensors: gradient control function, which can achieve different control functions according to different pressing forces and durations.

Is the membrane switch reliable

Although membrane switches have undergone market research and have established a foothold in fierce competition, they have gained the trust and love of a large number of users. However, its essence is still a manifestation of the application of thin film pressure sensors, and ultimately depends on the manufacturer's technical strength in the sensor industry and the solutions for product application. In the entire industry, the quality of products varies greatly, and the specifications are also diverse. What is the reliability of membrane switches? The membrane switch currently used in various products on the market is the best answer for those who are skeptical.

The reason why some users' processed membrane switches cannot work properly is not because the membrane switch technology is not good, but may be due to the quality problems of that manufacturer or their technical strength is not good. This is like a patient seeking medical treatment when they are sick. If you find a good doctor, you can cure the disease with medicine and regain vitality with skillful hands; If you find a quack like this among quack doctors, even if they use good medicine, if the medicine is not targeted, it can be a bad thing that is either incurable or life-threatening. As the saying goes, when you are sick, you should not seek medical treatment indiscriminately. Appropriate treatment is the most important, especially in the field of membrane switches. Our goal at Huiwen Technology is to strive for excellence in the production and manufacturing technology of thin film pressure sensors, and to become a trusted "miracle doctor" like Huatuo.