Application and characteristics of membrane switch

As we all know, switches play a role in transmitting command information in electronic products. There are many kinds of switches, and their development is constantly updated with the progress of electronic machine products. In the 1950s, the toggle switch, toggle switch and change-over switch of Endeavour element dominated; In the 1960s, the combination switch represented by the piano key switch appeared to complete simple function conversion; With the expansion of the application field and the increase of the whole machine functions, conductive rubber keyboard switches appeared again in the 1970s. The membrane switch is a new type of electronic device researched and developed in the late 1970s and early 1980s. It is a product that meets the needs of the miniaturization, digitalization, intelligence and multi-function development of the whole electronic product.

Membrane switch is a kind of contact switch, which is made by printing contact circuit with conductive paste on flexible polycarbonate or polyester film.

The membrane switch is a plane type, multi-layer combination, sealed structure, and an assembly of electronic whole machine control system integrating key switch, panel function mark, reading display transparent window, indicator window hole and circuit.

It has the following characteristics:

(1) Durability

The service life of the membrane switch can generally reach more than one million times. The reason for such a long service life is that the action of the switch is only realized by the spring of the elastic membrane in the vertical direction. Although the elastic film has undergone millions of times of creep, the creep amplitude is very small, only 0.1~0.3mm (i.e. switching travel). In addition, the material selection is reasonable, which is far from reaching the yield limit of the film. Therefore, the film material can withstand more than a million times of life without deformation. On the other hand, the contacts of the switch

It is vertical contact with little wear; The screen printed contact can form enough thickness, and a layer of conductive carbon is printed on the silver paste contact to achieve the purpose of high wear resistance and self-lubricating. Therefore, the service life of the membrane switch is more than ten times longer than that of the mechanical contact switch.

(2) Good sealing performance

Because the membrane switch is an integral sealing structure, the contact of the switch is not corroded by harmful gases and is not easy to be oxidized; It is waterproof and dust-proof, so it is more suitable for various harsh environments.

(3) Small size, light weight and reliable structure

The membrane switch can be arranged and combined into a membrane keyboard in design. Its setting density is large, and it is a sealed sheet structure composed of multilayer films. The connecting lines and outgoing lines between all switches are screen printed at one time, with a total thickness of 1~3mm. Therefore, the volume is reduced, the quality is reduced, and the reliability is improved.

(4) Rich colors and beautiful appearance

The membrane switch can be personalized in the design of color patterns according to the user's design concept, and can reflect the comprehensive characteristics of material beauty, decorative beauty and craft beauty in the decorative effect.

(5) Reduce the supporting cost of mechanical and electrical products

Traditional mechanical switches need to be welded during installation, or even matched with fixed supports. The membrane switch is installed as a stick on type. As long as the adhesive paper is removed, it can be firmly pasted on the surface of the whole machine. Its lead outlet is inserted into the socket of the rear circuit of the whole machine, and the circuit can be connected instantly. It saves labor and materials, and reduces the supporting cost of the whole machine.

2. Application

Membrane switch is a non self locking switch. It is applicable to the situations where the switching power is less than 1W, * working voltage: 42V (DC) or 25V (DC), * working current is less than 100mA. Can be widely used in all microcomputers, CNC. Intelligent instruments, meters and electronic circuits with discrimination and memory functions.