Products Introduction

Material types

There are requirements of flatness and printing adaptability for Membrane switches and panel materials, in addition, flexible and highly elastic characteristics are of more importance.

Polyvinyl Chloride PVC\60℃\0.175~0.5/glossy\ is stable to acids, alkali and salts at room temperature. And it is with good abrasion resistance, flame-resistant and self-extinguishing, sound and vibration damping, good electrical insulation. But it is with poor thermal stability.

Polycarbonate PC\-60 ~ 120 ℃ \0.175 ~ 1.0\ is with glossy high light transmission, low water absorption, good dimensional stability, in addition, bending, tensile, compressive strength is very superior. Heat resistance, cold resistance, electrical insulation and atmospheric aging resistance is excellent. But it is with poor drug resistance & fatigue resistance, so it is easily broken by stress cracking, output interface terminal circuit is printed by carbon material, and there is no protective coating, it will gradually form shedding layers when it is affected by air oxidation , which will lead to disconnection and end of life. This is where the membrane switch is prone to failures, mainly environmentally determined, the physical damage time is 3-10 years regardless of use it or not. Application scope for PC is wide, in addition, it can meet most of the requirements of the membrane switch panel, in which the high transmittance of glossy PC can meet the requirements of the window with liquid crystal display.

Sand surface polyester (PET)\-30~120℃\0.1~0.2 with glossy surface is drug resistance, insoluble in general organic solvents, not alkali resistance. It has excellent mechanical properties, electrical properties, rigidity, hardness and strong toughness in thermoplastics, low water absorption, excellent resistance to abrasion and friction, high dimensional stability. Tensile strength can be comparable to aluminum film, it is much higher than that of PC, PVC. It is inexpensive because the surface is difficult to process into a matte type, so the textured PET is more expensive. That’s why the textured PET is the ideal substrate to make membrane switch. What’s more, the textured PET is suitable for products with higher requirements on surface or with liquid crystal display window.

Material Thickness

Plastic substrate thickness 0.25mm and below is called film, it is mainly used as a membrane switch panel layer, the back of which is printed with a variety of indicative patterns and text to indicate the corresponding switch key position of the operating area, the choice of thickness should be based on the size of the panel and the key. The thicker the material is, the more force of touching and the slower the response is; the thinner the material is , the poorer the touching feel is, so does rebound. Thickness over 0.25mm is called plate,which is not suitable for three-dimensional key molding, but it can be used as a key-less operation area of the indicative signage panel, also it can be used as a membrane switch liner to improve its hardness.

Circuit layer substrate material:

The substrate for making circuits should be polyester (Polyethylene Phthalate) film (Polyester abbreviated as PET). It has good performance of insulation, heat resistance, high mechanical strength, transparency and air tightness, especially with folding resistance and high elasticity, so it is the ideal material for making membrane switch circuit.

Membrane Switch Structure

(1)Flat type without tactility : long service life, but without tactility;

(2)Film convex tactility: good tactility, but the service life is relatively short;

(3)Convex border type without tactility: beautiful appearance, a strong sense of three-dimensional, but no tactility;

(4)Convex frame tactility: beautiful appearance, strong sense of 3-D, and tactility

(5)Plate embossed tactile type

Type (a): When improper designed, it is easy to have the phenomenon of two sections, that is the plate is broken, but the electrical performance also exists;

Type (b): there is no two-section phenomenon, and the less structural layers, the more economical, when the plate is broken, electrical performance will not exist; 

(6) Metal shrapnel type:

Type (a): the basic and commonly used structure. The shrapnel plays both the role of touch and the role of the upper line;

type (b): It has complex structure and it is used in application which has more dense shrapnel and without jumper. Shrapnel was placed on the upper line, the upper and lower lines of conductive surface are placed 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 may be "two sections" . At the same time, the shrapnel is often in the excessive anti-concave state, so the shrapnel will not appear the phenomenon of rebound after a long time, which is recommended;

type (c): shrapnel placed in the upper line, only play a tactile role, the upper line conductive side down, the lower line conductive side up, there are "two sections", which is is not recommended;

type (d): shrapnel placed in the lower line, on and off the line are aligned, shrapnel not only play a tactile role but also play a role in connecting the upper and lower lines;  it is used in application which has more dense shrapnel and without jumper. Compared with (b) type, (d) type is of more structural simplicity. When designed, we should pay attention to line alignment to avoid the four legs of the shrapnel to ensure that there is no short circuit. 

(7）Luminescent body type: be sure to make primer mold

(a)LED circuit and the lower circuit in the same layer: simple structure, but the LED window should be convex, otherwise, the LED light will bump up plate; suitable for the use of shorter height of the small LED lights or LED lights with less number;

(b)LED circuit and the lower circuit not the same layer: complex structure, but the LED window does not necessarily have to be convex, suitable for two-color LED lamps or LED lamps in a larger numbers; which needs to make punching and primer molds

(8)Folding type: This type can avoid jumping lines , and the conductive surface can be directed downwards without making holes. Disadvantages of this structure is that the circuit of folding area is easy to break.

(9)Inner and outer frame waterproof type: The outer frame is a closed frame without any circuit, which serves as a protection for the inner frame and prevents moisture from circuit groove to enclosure.