Membrane switches sound very professional, in fact, the popular is the panel buttons, the name is more familiar with, many of the device's control panel use Membrane Switch, which is widely used in electronic communications, electronic measurement equipment, industrial control, medical equipment, Automotive industry, smart toys, household appliances and other fields. Next Xiaobian introduced the principles of membrane switch and membrane switch.
Membrane switch principle
Membrane switch is a multi-layer (planar) type (non-locking) key switch composed of a certain elastic insulating material layer, integrated circuit, key, indicating element, instrument panel and other functions. The movement of the membrane switch is only achieved by the elastic membrane in the vertical direction. The elastic membrane has a creepage of one million times, and the amplitude of the peristaltic movement is very small, only 0.1-0.3 MM, plus the rationality of material selection, so the membrane material It can withstand more than 1 million times of life without deformation, which determines the durability of the membrane switch.
Membrane switch has beautiful appearance, long service life, simple structure, convenient installation, good hand feeling, small occupied area, etc., and is widely used in all walks of life, from household appliances to high-tech products, slowly replacing Some touch switches have a huge share of the market and their advantages.
Membrane switch composition
1. The panel: The panel is the “outer garment” of the entire membrane switch. On the basis of proper arrangement of the keys, different colors, patterns, and key shapes are used to perform the necessary decorative effects on the entire membrane switch. The most important role of the panel layer is to identify and press buttons. Therefore, the materials must have high transparency, high ink adhesion, high elasticity, and anti-folding properties.
2. Upper circuit and lower circuit: The upper and lower circuits are the components of the electrical switch of the membrane switch and are also the “off” and “keys” of the switch. Its performance directly affects the performance of the switch electrical apparatus, and is mainly printed on the film. A layer of conductive material is formed. The upper and lower circuits act as the two electric shock roles necessary for the switch closure. The thickness is generally within 0.05--0.175mm. The most common is the use of 0.125mm PET.
3, surface glue, insulation layer, primer: The three-layer structure of the material are double-sided adhesive, due to the different positions in the switch structure and have different names. The three-layer double-sided tapes have different thicknesses depending on their respective layers. This is mainly determined by the thickness of the switch and the operating force of the keys.
Membrane switch by structure
1, flat type non-touch type
Long life, but no touch;
2, film convex touch type
Have a good touch, but the service life is relatively short;
3, convex frame type without touch
Beautiful appearance, strong three-dimensional, but no touch;
4, convex border touch type
Appearance is beautiful, there is a strong sense of three-dimensional, and there is a sense of touch;
5, face plate touch convex type
(a) Type: When the design is not proper, there are two phenomena easily, but the face plate is damaged, and the electrical performance also exists;
Type (b): There is no two-stage phenomenon, and there are few structural layers and it is more economical. If the panel is damaged, the electrical performance will not exist;
6, metal shrapnel type
Type (a): The most basic and most commonly used structure. The shrapnel acts as both a tactile and a line;
(b) type: The structure is complex, and it is used for occasions where the shrapnel is relatively dense and does not have jumpers. The shrapnel is placed on the upper line, and the upper and lower lines of the conductive surface are all upward, and the upper line needs punching. When the structure is turned on, the four legs of the spring clip are not in the same plane as the center point, and a "two-stage" situation occurs. At the same time, the shrapnel is often in a state of excessive anti-concavity. After a long time, the shrapnel will not rebound. It is not recommended.
(c) Type: The shrapnel is placed on the upper line, only acts as a touch, the upper line of the line is facing downwards, and the lower line is facing upwards. There is a “two-stage” situation and is not recommended;
(d) type: The shrapnel is placed on the lower line. Both the upper and lower lines have a track. The shrapnel acts as a tactile sensation and connects the upper and lower lines; it is used for more shrapnel, denser, and less hops. Lines are simpler than type (b). When designing, pay attention to the wiring of the circuit to avoid the four legs of the spring to ensure that there is no short circuit.
7, luminous body type: must open the bottom mold
(a) The LED line is the same layer as the lower line: the structure is simple, but if the selected LED lamp height is high, the LED lamp will push up the panel. At this time, the LED window on the panel should be treated as convex or thickened. The thickness is greater than the thickness of the LED lamp;
(b) Different layers of the LED line and the lower line: The structure is complicated, but the LED window does not have to be convex, but the upper area of the LED lamp must be hollowed out to prevent light from passing through the LED lamp hole. It should be noted that at this time, it is necessary to avoid the wiring around the LED lamp hole when the lower line is being routed.
8, folded type
This type can avoid jumpers and can prevent the conductive surface from going down without holes. The disadvantage of this structure is that it is easy to break the circuit at the fold.
9, inside and outside the box waterproof type
The outer frame is a closed frame with no traces, which protects the inner frame and prevents moisture from entering the housing from the outlet groove.
Editor's summary: The principle of the membrane switch and the composition of the membrane switch are introduced here. We hope to help everyone. If you want to know more about yourself, you can follow the information on this site.
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