Deep analysis of touch screen technology
Find out what the design needs is the most important first step in touch design. Many of the providers on the touchscreen supply chain often offer many confusing different components, and more often some providers are united to provide a value chain for end customers. Figure 1 shows the structure of the touch screen ecosystem. Interestingly, the ecosystem is the same for both the latest laptops and the latest touchscreen phones.
1, front panel or frame
The front panel or frame is the top surface of the end product. In some products, the frame will be transparent cover plate enclosed, so as not to be affected by the external bad weather or moisture, but also to prevent the following sensing products are scored and destroyed. There are times when the outermost box is simply covered over the touch sensor, which in this case is just a decoration.
2, touch controller
Typically, the touch controller is a small microcontroller chip that is located between the touch sensor and the PC / or embedded system controller. The chip can be mounted on the controller board inside the system, or it can be placed on a flexible printed circuit (FPC) that is pasted onto a glass touch sensor. The touch controller extracts the information from the touch sensor and converts it into information that the PC or embedded system controller can understand.
3, touch sensing
Touchscreen “Sensor” is a transparent glass plate with a touch-responsive surface. The sensor is mounted 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 using a different method to detect touch input. Basically, these techniques are in touch, so that current flows through the panel, resulting in a voltage or signal changes. 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 LCDs. LCD selection for touch products and traditional systems are basically the same, including resolution, clarity, refresh speed, cost and so on. But another major consideration in the touch screen is the radiation level. Because the technology in the touch sensor is based on the tiny electrical changes that the panel is touched, it is difficult to radiate many electrical noise LCDs. Before selecting an LCD for touching the system, you should consult with the touch sensor provider.
5, the system software
Touchscreen driver software can come from the original manufacturer (such as mobile phone embedded OS), it can be later installed software (like a traditional PC plus a touch screen). The software should enable the touch screen and the system controller to work together. It will tell the product’s operating system how to resolve touch events from the touch controller information. In PC-type applications, the vast majority of touch-screen drivers work like a mouse. This makes the touch screen very similar to the mouse on the same position on the screen. In an embedded system, the embedded control driver must match the information that appears on the screen with the location where the touch is received.

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