Projected capacitive touch technology and surface capacitive touch technology TFT Display Module

PCT is built on the concept of a matrix. In part of touchscreen Country, the the PCT panel of ITO etched to produce a specific pattern, in order to improve the signal-to-noise ratio of each contact, and to enhance the recognition accuracy. According to the scan mode, generally can be divided into self-capacitance and mutual capacitance two:TFT Lcd Modules
Self-capacitance, usually refers to the scan electrodes and the capacitor constituted. In the glass surface, the horizontal and vertical scanning electrode made of ITO, the poles of a capacitor is formed between these electrodes and the ground, when the fingers touch the human body capacitance generated in parallel to the circuit caused by a change in capacitance, the capacitor control by projections the contact point of the coordinate values ​​of the detected value of this change.
Mutual capacitance, generally refers to the coupling capacitance is formed between the glass surface of the lateral and longitudinal ITO electrode. Mutual capacitance detection method is to determine the position of the touch point by detecting each crossing point of the capacitance change. When the touch of the human body, the electric field of the electrode is reduced by the influence of the human body, thus affecting the size of the coupling capacitor. Capacitance controller is able to detect the change in capacitance, by processing these changes, you can get accurate coordinate information. Because the mutual capacitance scanning method is to detect the variation of capacitance values ​​of each intersection, so it needs to scan time longer need to detect X * Y data, but it is precisely because of this detection method, it can achieve a true multi-point touch detection.Character LCD Display

Surface capacitive touch technology (SCT):
SCT the panel is a uniform distribution of the ITO layer, the four corners of the panel each have one lead connected to the controller SCT. SCT controller internal driving circuit panel for charging, and the formation of a uniform electric field, electric field change caused by a very small amount of current flows when the finger touch. In this case, the detection circuit inside the IC amount of current analytical four-line, respectively, and calculate the amount of data according to the various points X, Y coordinates. In order to overcome the interference, the filter hardware or software filters for processing coordinate values ​​derived.