To continuously update and break through in the design of touch products, understanding the requirements of design is the first and most important  step. The touch screen is composed of lens (panel), TP Sensor (contact sensor), FPC (flexible circuit board), IC (touch chip) and other accessories.

The common ones are resistive and capacitive touch, and capacitive touch screens are more commonly used on mobile phones and tablets. The capacitive touch screen can realize multi-touch, it is with sensitive operation, not easy to touch by mistake, and high durability. Capacitive touch screens can only be operated when they sense the current of the human body, avoiding the touch of other objects, and perform well in terms of dustproof, waterproof, and abrasion resistance. Capacitive touch screens have a long life and do not require pressure to generate signals. Just touch it directly can it generate signals.

Then the ecosystem structure of a touch screen can probably be understood from the following 5 points

1.Panel

The front panel or frame is the outermost layer of the touch screen. In the touch screen, the outer frame encloses a transparent cover plate to avoid being affected by external harsh weather or humidity, and also to prevent the following sensing products from being scratched and damaged. Sometimes, the outermost frame simply covers the top of the touch sensor. In this case, it is just a decoration.

2. Touch chip

Generally, the touch controller is a small microcontroller chip located between the touch sensor and the PC/or embedded system controller. The chip can be assembled on the controller board inside the system, or it can be placed on a flexible printed circuit (FPC) glued to the glass touch sensor. The touch controller will extract the information from the touch sensor and convert it into information that the PC or embedded system controller can understand.

3. Touch sensor

The touch screen sensor is a transparent glass plate with a touch-responsive surface. The sensor is placed on the LCD so that the touch area of the panel can cover the visible area of the display. There are many different touch sensing technologies on the market today, each of which uses a different method to detect touch input. Basically, when the current  flow through the panel during touch, thereby generating a voltage or signal change. This voltage change will be sensed by the touch controller to determine the touch position on the screen.

4. Liquid crystal display (LCD)

The vast majority of touch screen systems are used on traditional LCD. The LCD selection method for touch products is basically the same as in traditional systems, including resolution, clarity, refresh speed, cost, etc. But another major consideration in touch screens is the radiation level. Since the technology in the touch sensor is based on the tiny electrical changes generated by the touch panel, an LCD that can radiate a lot of electrical noise is a difficult point in the design. Before selecting an LCD for use in a touch system, you should negotiate with the touch sensor provider.

5. System software

The touch screen driver software can come from the original manufacturer (such as the embedded OS in the mobile phone), or it can be later installed software (such as adding a touch screen to a traditional PC). The software should enable the touch screen and the system controller to work together. It will tell the product's operating system how to parse the touch event information from the touch controller. In PC-type applications, most touch screen drivers work like a mouse. This makes the touch screen very similar to pressing the mouse continuously on the same position on the screen. In an embedded system, the embedded control driver must compare the information that appears on the screen with the position where the touch is received.