Touch screen embedded systems theory TFT Display Module

Touch screen attached to the surface of the display, with the display compatible use, if the touch point can measure the coordinate position on the screen, may be based on the corresponding coordinate points on the display or the display icons informed intention of touching. Touch screen can be divided into five categories according to their technical principles: vector pressure sensor, resistive, capacitive, infrared, surface acoustic wave, resistive touch screen which in embedded systems with more. Resistive touch screen is a four-layer composite film of a transparent screen, shown in Figure 2, the bottom is composed of glass or plexiglass grass, the top layer of the outer surface is so smooth and scratch-resistant hardened plastic layer, the middle two layers of conductive metal layer, respectively, at the grassroots level and the plastic layer on top of the inner surface of the conductive layer between two transparent isolation of many small points separate them. When a finger touches the screen, the two conductive layers in contact with the touch point. Character OLED Display
Touchscreen two metal conductive layers are two face touch screen, each end of each face is coated with a silver plastic, known as the face of a pair of electrodes, if a face is applied to the upper electrode voltage, in which the working surface will form a continuous parallel uniform voltage distribution. Shown in Figure 1, when the X-direction electrodes for applying a voltage determined, and the Y direction on the electrode when no voltage is applied, the voltage of the X parallel to the field, the voltage value at the contact in the Y + (or Y -) electrode reflected Y + by measuring the magnitude of the voltage electrode to ground contact will be aware of the X-coordinate value. Similarly, when a voltage is applied to the Y electrode, and the X electrode when no voltage by measuring the voltage of the electrode X +, Y coordinate of contact will be aware. Resistive touch screen with four lines and five line two. Four-wire touch screen X and Y face face increases in the two conductive layers, respectively, a total of four lead, are connected to a touch screen on the X electrode and the Y electrode pair. Five-wire touch screen face the X and Y are added to the face of the conductive coating on a glass substrate, but the work is still sharing the applied voltage, ie voltage field in both directions at the same time sharing the work face , the outer conductive layer is only used as a conductor and the voltage measuring electrodes. Therefore, the five-wire touch screen pinout need to 5. TFT Lcd Modules