Unveil the Mysteries of Capacitive Touch Screens

Traditional resistive touch screens are considerably different from capacitive touch screens. When running, resistive touch screens can only judge one touch point at a time. If there are more than two points, a proper judgment cannot be formed.

As a result, resistive touch screens are only used for simple action decisions such as clicking, dragging, and a few others. While using a capacitive touch screen, the user's touch can be broken down into a series of multi-point signals and judgment signals, allowing for the completion of complex action judgement.

In truth, the touch screen's operating concept is essentially the same, whether it's a regular LCD screen or a transparent touch panel. The resistive and capacitive varieties are distinguished by their different operating principles.

The four types of touch screens currently in use are resistive touch panels, capacitive touch screens, infrared touch screens, and surface acoustic wave touch screens. Resistive touch screens, which are commonly utilized in mobile phones and portable digital items, are the ones we are most familiar with in real life.


Ⅰ. The basis of a resistive touch screen operation

The principal application of a resistive touch screen is for pressure sensing control. It's made up of a screen and a resistive film screen that fits snugly over it. The resistive film screen is usually divided into two layers: one layer is made up of a glass or plexiglass base with a transparent conductive layer on its surface.

The base is pressed outside of our usual direct contact with the plastic layer of hardened and scratch-resistant, and the plastic layer of resistive touch screen is pressed inside the same layer of conductive layer. Separated from each other are the two conductive layers.

When we touch the screen with our fingers or other things, the two conductive layers come into contact, and the resistance changes. The controller determines the coordinates of the contact point and the accompanying operation based on the precise changes in resistance.

Ⅱ. The working principles of capacitive touch screens

Capacitive touch screens, unlike resistive touch screens, work by using the current induction of the body. The inner surface of the glass screen is laminated with a layer of conductive layer, and the outermost layer is a thin layer of silica glass protective layer. The induction screen of capacitive touch screen is a four-layer composites glass screen.

The electric field of human allows the finger and the capacitive touch screen surface to form a coupling capacitance when we touch the inductive screen with our finger. Because the capacitance is a direct conductor for high frequency currents, the finger draws a small current from the contact point.

The current flowing through the electrodes on the four corners of the touch screen is proportional to the distance between the finger and the four corners, and the controller calculates the position of the touch point by calculating the proportion of these four currents.

Ⅲ. What are the advantages of capacitive touch screen over the traditional resistive touch screen?

1. Operational novelty. Multi-touch is supported by capacitive touch screens, making operation more intuitive and engaging.

2. It's less likely to touch by accident. Because a capacitive touch screen relies on the body's current to operate, which can only be operated by the human body. Therefore, when other objects touch it, it will not respond, which basically avoids the possibility of accidental touch.

3. Extremely long-lasting application. Capacitive touch screens outperform resistive touch screens in terms of dust resistance, waterproofness, wear resistance, and other factors.