Capacitive Touch Panel (also known as CTP, Capacitive Touch Panel), which works by utilizing the current sensing of the human body. Capacitive touch screen is a four-layer composite glass screen, the inner surface of the glass screen and laminated each coated with a layer of ITO, the outermost layer is a thin layer of silica glass protective layer, laminated ITO coating as a working surface, the four corners of the four electrodes, the inner layer of ITO for the shielding layer to ensure a good working environment. When the finger touch in the metal layer, due to the human body electric field, the user and the surface of the touch screen to form a coupling capacitance, for high-frequency current, capacitance is a direct conductor, so the finger from the point of contact to suck a very small current. This current from the four corners of the touch screen electrode outflow, and flow through the four electrodes of the current and the finger to the four corners of the distance is proportional to the controller through the proportion of the four current is calculated accurately, resulting in the location of the touch point.

Nowadays, capacitive touch screen has become a mainstream product in the current display industry, widely used in cell phones, tablet PCs and other consumer electronics. It supports gesture operations such as scrolling, zooming, pinching, etc., and provides a smooth interactive experience that is incomparable to resistive touch screens.

I. Capacitive Touch Controller  

Capacitive touch controller is the core component to realize the function of capacitive screen. Usually, capacitive touch controllers for consumer electronics products have a shorter life cycle, and their design has a strong market bias and is constantly optimized for cost. As market demand changes, such controllers may face revision or discontinuation, and their life cycle is usually only 2-3 years. In contrast, industrial display capacitive touch controllers are more focused on performance stability and longevity. This means that some driver ICs may not require any changes for a decade or more. This characteristic is exactly what the industrial display field is looking for and what the industry expects. Once developed, the product does not require frequent adjustments or updates over a long period of time.

Anti-interference capability  

Capacitive screens realize coordinate positioning by detecting changes in capacitance values, so the accuracy of capacitance values is critical. However, capacitance values are susceptible to a variety of interfering factors, such as AC power supplies, inverter motors, GSM antennas, sensing chips, and stray signals. These interferences may lead to inaccurate RXTX coupling capacitance values, which may cause problems such as incorrect contact positioning, unresponsive contacts, or automatic triggering. Therefore, the anti-interference capability of capacitive touch driver ICs is particularly critical. Strong anti-interference design can effectively avoid the above problems and ensure the stability and reliability of the touch screen.

Second, electromagnetic compatibility, ESD and so on:

Third, the advantages and disadvantages of CTP:

Advantages:

. Novelty and intuitive operation: support for multi-touch, making the operation more intuitive and interesting.

. Not easy to accidentally touch: because of the need to sense the human body's current, so only the human body can be operated, other objects will not react when touched, effectively avoiding the possibility of accidental contact.

. High durability: better structural design, can effectively prevent dust, stains on the contact position, with better dustproof, waterproof, wear-resistant characteristics.

Disadvantages:

. Higher cost: compared to other types of touch screens, capacitive touch screens are more expensive to manufacture.

. Poor anti-interference ability: it may cause malfunction in a humid environment or when there is a large conductor nearby.