Membrane switches are structurally divided into two categories: tactile and non-tactile. The non-touch type usually has a flat type of non-touch type and a convex button frame (in some cases, a blind spot) and has no tactile sensation.

The non-touch type membrane switch does not require a hand, but the sensitivity is high, and the touch is turned on, but the button cannot be short-circuited when the button is not pressed, so a reasonable isolation point should be added to the lower circuit key body. The buttons of the early non-tactile membrane switch used color to express the position, shape and size of the key body, and the operator visually recognized the operation. In order to facilitate the operation and improve the accuracy, the panel is designed to be a button frame protrusion or a blind spot protrusion. In recent years, many flat-touchless membrane switches have been changed to capacitive membrane switches.

The touch-sensitive membrane switch has many structural forms, and the most classic ones are the blister touch type and the elastic piece (pot).

Commonly used in the blister touch type, there are two types of upper circuit and panel bulge and panel blister. Some ultra-thin structures remove the upper circuit, and the upper circuit contacts are directly printed on the panel. The blister of the membrane switch is made by heating and hydraulicizing the mold, so that the key body is slightly bulged, slightly higher than the panel, forming a three-dimensional shape of the membrane switch button, the material is selected to be very tough and heat-shrinkable PET, hot pressing The bubble forms a resilience, so the touch of the blister touch membrane switch is very good, and the pressing performance is sensitive, but care should not be used for a long time in a high temperature environment, and the high temperature may cause the button feel to be weakened. The blister-type membrane switch generally uses the upper circuit and the panel to have convex blister. When the upper circuit is not convex, the filter should be filtered at the position of the venting groove, and the upper circuit is opened for the small hole, and if necessary, the lower circuit. The contact points are added with reasonable isolation points to avoid the shortcomings of short circuit and connection; if the contacts are directly printed on the panel, the filter should be filtered until the panel is deformed by high temperature, and the deformation time of the panel is too long. The deformation is large, which causes great trouble to the assembly and paste of the membrane switch. When the baking time of the high temperature is too short, the contact aging time on the panel is not enough, the contact is easy to wear, and the service life of the product is shortened.

The shrapnel (pot) is a touch-sensitive membrane switch, which means that the shrapnel is fixed on the lower circuit to form a pole as an upper circuit, and when the shrapnel is pressed, it communicates with another pole of the lower circuit to form a loop. The buttons of the shrapnel touch-sensitive membrane switch can be designed to be diversified, which makes the product more stable and reliable, and at the same time enhances the decorative effect of the product and achieves a perfect appearance. The panel can be designed as a plane, a convex spherical surface, a convex plane, and the shape can be an irregular shape such as a circle, a square, a triangle, or the like. When the button is designed as a flat or convex button border and a blind spot, the surface layer should be thickened, There is enough space to make the stroke of the shrapnel freely. If the feel is not good, add a small spacer on the back of the panel button; the design of the fixed layer of the shrapnel can be divided into punches at the corresponding key positions (the hole diameter is smaller than the shrapnel) ) or bubbling two forms, the punch design will be more crisp and even, and the bubbling design will have better overall sealing. The second structure of the shrapnel type refers to the fact that the shrapnel is directly applied to the key position of the upper circuit to enhance the hand feeling. In the case where the number of the keys is particularly large and the overall shape is small, and the space is not arranged, the upper and lower circuit structures are designed to adopt this structure. Form, but the sensitivity of this structure is slightly weaker, the pressure of pressing is slightly larger, and the time of releasing the finger is slightly longer. Sometimes there is a feeling of pressing and the sound of the shrapnel is heard and the circuit is not turned on. .
 
The LED embedded membrane switch has two structures: the LED line and the lower layer of the same layer in the same layer.
     The structure of the same layer of the LED circuit and the lower circuit is relatively simple, but the LED window should be bubbling. Otherwise, the LED lamp will jack up the panel, and the LED is also easily damaged by heavy pressure. The LED of the 0603 is shorter in height but smaller in pad. It is difficult to solder. The LED height of 0806 is 0.8mm. The pad is larger and the soldering is less. The structure of the different layers of the LED circuit and the lower circuit is relatively complicated, but the thickness of the whole membrane switch is thick. It is not necessary to bubble. The membrane switch with LED has to design an electrostatic shielding layer on the panel. The green and blue LEDs are easily broken by static electricity, especially in winter.
     Waterproof two structures, the waterproof structure is generally designed as a retro-shaped embedded structure, one structure is exactly the same material, the two parts are finished, and the circuit part is embedded into the panel part into one product. This kind of structure is more commonly used, each layer of glue should use waterproof glue; the other structure is the material of the thickness of the upper and lower circuit and the isolation layer, and the outer frame structure of the membrane switch is made with the panel, and the circuit part is embedded inside. Into a whole. Waterproof glue can generally be used 3M9495LE or 3MGTM920.

     The light guiding type structure refers to embedding a light guide sheet in a conventional membrane switch, and illuminating the button with a side light LED (EL cold light sheet can also be used). Make the membrane switch use at night and in low light, more ornamental. To make a light-guide type membrane switch, it is necessary to consider that the side of the panel and the membrane switch should not leak light and cross-talk, and all double-sided adhesives should use black glue. After the light guide is added, the button feel is weakened, and a gasket is added on the back of the button position of the panel to enhance the hand feeling.
   
     The double-fold structure is also considered to be adopted in the case of a large number of buttons and a small overall shape without wiring at the position of the space. The structure is designed as an upper and lower circuit structure. This structure pays special attention to the hemming process to be carried out under heating, taking into account the service life. The increase in the impact on the bend.

     Each structure has its own characteristics. At the beginning of the design, the most suitable structure is selected to produce high-quality products and serve the users.