Resistance to electromagnetic interference of capacitive touch screens can be achieved through the following structural design:
Capacitor board isolation: In the structural design of the capacitor touch screen, the physical isolation of the capacitor board and other circuit boards can be used to avoid the conduction of electromagnetic interference. The shield or metal isolation layer is placed around the capacitor board to prevent the influence of external electromagnetic fields on the capacitor board.
Grounding design: A reasonable grounding design can reduce the interference of electromagnetic noise on the capacitive touch screen. In the design, it is necessary to establish a good grounding path, and connect the grounding line closely with the main control chip and the shielding layer, so that the interference signal can be quickly introduced to the ground.
Shielding layer: Capacitive touch screens usually add a shielding layer near the glass or plastic surface to shield interference from external electromagnetic waves. The shielding layer can absorb or reflect most of the electromagnetic radiation, reducing the impact on the touch screen capacitive sensor. Commonly used shielding materials are metal oxides, metal films, etc., such as ITO (indium tin oxide).
Filters: The use of filters in capacitive touch screen circuits can suppress high-frequency noise and stray signals, reducing the impact of electromagnetic interference. Common filters include RC filters and LC filters, which can be used to filter out interference signals.
Ground layout: A reasonable ground layout can reduce the impact of electromagnetic interference on the capacitive touch screen. In the design, the length of the ground wire should be shortened as much as possible and the area of the loop should be reduced. At the same time, the ground cable of the touch screen needs to be isolated from other circuits to avoid interference caused by shared ground cables.
Coupling capacitance reduction: Coupling capacitance refers to the capacitor interaction between different parts of the capacitive touch screen circuit. By optimizing the circuit layout and reducing the cross interference between capacitor boards, the coupling capacitance can be reduced and the anti-interference ability can be improved.
In terms of electromagnetic shielding, the following are several common types of glass, which have different shielding performance and application scenarios:
ITO (indium tin oxide) glass: ITO glass is one of the most common electromagnetic shielding materials. It forms a conductive layer on the glass by depositing a thin film of indium tin oxide on the glass surface. ITO glass has high transparency and good conductivity, and can be used for electromagnetic shielding in touch screen, display and other fields.
AMG (Metal mesh) glass: AMG glass is an electromagnetic shielding material composed of a metal mesh. The metal mesh is distributed in a uniform manner on the glass surface and blocks electromagnetic radiation through an effective shielding structure. AMG glass is suitable for electronic equipment, wireless communication and other fields, can provide a high shielding effect.
AGC (aluminate glass) : AGC glass is a special glass with good electromagnetic shielding properties. It doping specific metal ions, so that the glass has a high conductivity and shielding ability. AGC glass is widely used in electronic display, solar cells, information technology and other fields.
XIR (colorless infrared) glass: XIR glass is a special glass with infrared shielding function. It can effectively block infrared radiation by introducing special chemical elements into the composition of the glass. XIR glass is mainly used in infrared sensors, thermal imaging equipment and other fields to provide excellent electromagnetic shielding performance.