four-wire resistive touch screen

Principle of four-wire resistive touch screen

The surface touched by the finger is a hard coating to protect the underlying PET layer. The PET layer is a thin, flexible PET film that bends downward when the surface is touched, and allows the two layers of ITO coatings below to contact each other and connect the circuit at this point. Between the two ITO layers are some isolation fulcrums about one thousandth of an inch thick to separate the two layers. Multilayer polyester structure, also called plastic-plastic-glass (plexiglass) structure. Due to the layered structure attached to the back of the glass or plastic by the adhesive, the additional layer produced will reduce the light clarity, and in long-term use, it is easy to produce inter-Film delamination and linear decline due to film type deformation. At the bottom is a transparent hard bottom to support the structure above, usually glass or plastic. The multilayer structure of the resistive touch screen will cause a large light loss. For handheld devices, it is usually necessary to increase the backlight source to compensate for the problem of poor light transmission, but this will also increase battery consumption. The advantage of resistive touch screen is that its screen and control system are relatively cheap, and the response sensitivity is also very good.

Touch coordinates and electric shock pressure

The ITO ceramic layer is divided into upper and lower layers, separated by an isolation fulcrum in the middle, the two layers are the X layer and the Y layer. The four-wire resistive touch screen can not only get the X/Y coordinates of the contacts, but also measure the pressure of the contacts. This is because after pressing the touch screen, the upper and lower ITO layers are in contact, and there is actually resistance on the contacts. The larger the contact, the smaller the resistance. The pressure can be quantified by measuring the resistance.