About the controller!
Engineering firms that want to use touchscreens in their designs must dedicate significant time to evaluating the most suitable technology for each application and operating environment. This is not surprising, as there are different types of technology, and an error in selection can have very negative repercussions on the success of the final product.
For example, standard resistive and capacitive technologies might seem attractive at first glance due to their low cost, but if the location where they will be used lacks surveillance or is outdoors, they are no longer recommended because of how easily the user can damage them, since their active sensors are located on the outside of the glass. Furthermore, these technologies do not function correctly when certain amounts of liquid are deposited on the glass surface.
Other technologies, such as infrared or acoustic wave touchscreens, require a frame around their entire perimeter to prevent dust or grease from accumulating on the sensors, as this affects not only the functionality of the touchscreen but also the aesthetics of the machine. Furthermore, these technologies are highly sensitive to shocks and vibrations. Acoustic wave technology is also sensitive to all types of liquids, negatively impacting its proper functioning.
For all these reasons, designers are increasingly choosing a technology that allows for complete touchscreen protection through safety glass.
The solution is Projected Capacitive Technology (PCT™) patented by Zytronic, which uses an array of capacitive copper wires (10 µm thick) arranged in an XY configuration and embedded in a laminated substrate (see Figure 1). Since the substrate is located behind an overlay layer (usually glass or polycarbonate) up to 20 mm thick, the sensors are protected from dust, water ingress, scratches, and impacts, and even withstand extreme temperatures.

However, while sensor characteristics are an essential element in the design process, other aspects must be considered, such as the characteristics of the touch controller used. As the 'brain' of any touch system, this essential component is responsible for collecting and interpreting data from the screen and transmitting it to the host computer (see Figure 2). Even high-performance monitors with integrated touchscreens, when paired with a powerful computer, can experience significant performance limitations if the touch controller does not meet expectations.

Advances in Controllers:
As touch technology becomes more widespread, the need grows to develop increasingly sophisticated controllers to meet the evolving demands with ever-increasing performance levels and new functionalities. Among the factors driving the development of new technologies and control systems is the ability to optimize response times on larger touchscreens to achieve maximum speed in the interaction between the user and the final product.
New controllers, in which many components are integrated into a single integrated circuit (ASIC), simplify the design (see Figure 3) while offering greater flexibility in device placement and ease of use. Depending on the application, engineers can even integrate the controller chip onto the motherboard, thus reducing the number of components and potential sources of failure, resulting in higher reliability.
At the same time, these new controllers help improve the signal-to-noise ratio (SMR) and contribute to increased touch sensitivity. In the case of PCT touchscreens, this allows for an increase in the thickness of the front glass, thus achieving higher levels of vandal protection (Figure 4 shows a PCT touchscreen used in an interactive "Shop Windows" display).

Along with more stringent integration requirements, there is a need to build higher-performance controllers, improve microprocessors with higher performance, and increase the capacity of onboard flash memory. This results in greater performance, allowing for faster response times and increased accuracy, while also enabling the optimization of performance for the advanced algorithms required to support features such as multitouch.
The advantages of multitouch have been increasingly in demand in the consumer market since the release of the Microsoft® Windows® 7 operating system, which supports multitouch input. Consequently, this feature is also beginning to be requested in the industrial market. With multitouch, users can drag and drop icons and files, cut and paste text, recreate graphics, and pan, zoom, and rotate images on the screen for applications such as photo viewing and 3D design.

Summary:
The evolution of touch technology associated with controllers will continue to accelerate as the demand for touchscreen technology grows. The new generation of high-performance controllers is poised to significantly improve the performance of touch systems, delivering greater speed and precision in a more compact design. This simplifies manufacturing and adjustment processes while reducing inventory management and costs. The new generation of controllers will offer new levels of functionality, including multi-touch operation, on-the-fly firmware updates, and advanced interaction methods.