Principle of membrane switch
Membrane switch is a certain flexibility of the insulating material layer composed of a multi-layer structure (plane) type (non-locking) key switch, integrated circuit. Keys, indicating elements, instrument panels and other functions as a whole. Membrane switch action only by the vertical direction of the elastic film bouncing to achieve, the elastic film, although after millions of times of creep, and creep when the amplitude is very small, only 0.1-0.3MM, coupled with the reasonableness of the choice of materials, so the film material can withstand a million times more than a large life without deformation, these are the durability of the decision of the membrane switch.
Membrane switches are characterized by beautiful appearance, long service life, simple structure, easy installation, good feel, small footprint, etc., and are widely used in all walks of life, from small household appliances to high-tech products, slowly replacing some of the light touch switch market, occupying a huge share of the market and advantage.
Membrane switch composition
1, panel: the panel is the whole membrane switch "coat", in the appropriate arrangement of the keys on the basis of different colors, patterns, key shapes, the whole membrane switch to play a necessary decorative role. The main role of the panel layer is to play the role of marking and key, so the choice of materials must have high transparency, high ink adhesion, high elasticity, anti-folding and other characteristics.
2, the upper circuit, the lower circuit: the upper and lower circuits are the electrical components of the membrane switch, but also the switch "off" "key" where its performance directly affects the switch electrical performance, mainly by printing a layer of conductive material on the film. It is mainly formed by printing a layer of conductive material on the film. The upper and lower circuits bear the two electrochemical roles necessary for the closure of the switch, the thickness of which is generally within 0.05-0.175MM, the most common is to use 0.125MMPET.
3, surface adhesive, isolation layer, bottom adhesive: these three layers of structural materials are double-sided adhesive, due to the different positions in the switch structure and have different names. The three layers of double-sided adhesive by their respective levels of different and different thickness, this is mainly based on the thickness of the switch, the operating force of the key to decide.
Membrane switches are classified by structure
1, flat non-tactile type
Long service life, but no tactile sensation;
2, film convex tactile type
Good tactile sensation, but the service life is relatively shorter;
3, convex bezel-type non-tactile type
Aesthetically pleasing appearance, has a strong three-dimensional sense, but no Tactile;
4. Convex frame tactile type
Beautiful appearance, strong three-dimensionality, and tactile;
5. Convex tactile faceplate
(a) type: when the design is not right, it is easy to have the phenomenon of two segments, but the faceplate is broken, the electrical performance also exists;
(b) type: there is no phenomenon of two segments, and the structure of the layer is less, more economical.
6, metal shrapnel type
(a) type: the most basic and most commonly used structure. Shrapnel plays both the role of touch and the role of the upper line;
(b) type: complex structure, used for more dense shrapnel and do not have to jump the line of the occasion. Shrapnel placed on the upper line, the upper and lower lines of the conductive surface are up, the upper line needs to be punched. This structure of the four feet and the center of the shrapnel conductive point is not in the same plane, there are "two sections" of the situation. At the same time, the shrapnel is often in excessive anti-concave state, after a long time, the shrapnel will not rebound phenomenon, is not recommended;
(c) type: the shrapnel is placed in the upper line, only play a tactile role, and its upper line conductive surface down, the lower line conductive surface up, there is a "two-section" of the situation, is not recommended;
(d) type: shrapnel placed in the lower line, the upper and lower lines are aligned, the shrapnel both play a tactile role and play a role in connecting the upper and lower lines; used for more shrapnel, denser and do not want to have a jumper occasions, simpler than the structure of the (b) type. Designed to pay attention to the line alignment to avoid the four legs of the shrapnel to ensure that there is no short circuit.
7, light-emitting body type: be sure to open the bottom of the rubber mold
(a) LED lines and the lower line with the same layer: the structure is simple, but if the selected LED lamp height is high, LED lamps will be topped up the panel, at this time should be the panel on the LED window to do convex processing, or thickening of the surface of the rubber layer thickness, so that its thickness is greater than the thickness of the LED lamp;
(b) LED Line and the lower line of different layers: the structure is complex, but the LED window does not have to be convex, but must be hollowed out in the upper area of the LED lights to prevent the light can not pass through the LED light holes. Note: At this time, the lower line alignment needs to be avoided around the LED light hole alignment.
8, folded
This type can be avoided to avoid jumping lines and do not need to make the conductive surface can be down the hole, the disadvantage of this structure in the folded easily line is easy to break.
9, inside and outside the frame of the waterproof type
The outer frame is a closed frame, there is no line, the inner frame to play a protective role in preventing moisture from the line notch into the chassis.