Working Principle of LCD Touch Screen

Usually the working part of the touch LCD screen is generally composed of three parts: there are two layers of transparent resistive conductor layer, the isolation layer between the two layers of conductors and the electrode. Resistive conductor layer is generally made of resistive materials, such as indium tin oxide coated on the substrate, the upper substrate using plastic, the lower substrate using glass. The isolation layer is a viscous insulating liquid material, such as polyester film. The conductive property of the electrode is about 1000 times that of ITO. 
 
When touching the lcd display screen, the upper and lower conductor layer is equivalent to the resistance network, as shown in the figure above. When a certain layer of electrode adds voltage, a voltage gradient is formed on the network. If there is an external force that causes the upper and lower layers to contact at one point, the voltage at the contact point can be measured at the other layer where the voltage is not applied to the electrode, and the coordinates of the contact point can be obtained. If a voltage is added to the electrode at the top layer, a voltage gradient is formed on the top conductor layer, and if there is an external force that causes the upper and lower layers to contact at a certain point, the voltage at the contact point can be measured at the bottom layer. Then according to the distance relationship between the voltage and the electrode, we know the X coordinates here. The voltage is then switched to the bottom electrode and the voltage at the contact point is measured at the top level to know the Y coordinates.

XIANHENG specializes in the production and sale of touch LCD screens such as industrial display screen, industrial touch screen and optical fitting. The products are widely used in medical equipment, industrial handheld terminals, Internet of Things terminals and smart home. Any questions please feel free to contact us by e-mail to [email protected].