Touch sensors are increasingly integrated into 4K interactive digital signage to create immersive interactive visual experience. Know and understand how to overcome the common technical obstacles of 4K interactive digital signage is the key to the success of the installation. The following lists three common challenges to achieve 4K interactive digital signage:
4K displays have a high electronic interference (EMI), so the need for better pixel density of the driver circuit to increase the complexity of the. This can be increased by three to four times the interference with respect to the normal HD display. This interference or noise, so that the touch screen and control electronics is more difficult to identify the surrounding noise. This reduces the signal to noise ratio, but also the real touch identification. In other words, increased interference reduces the accuracy of touch sensing.
An improved touch controller for electronic design and touch detection firmware is necessary to ensure that the integrity of the signal is maintained at a high level. The projected capacitive touch technology (P-CAP) is embedded in the X-Y matrix of the laminated glass substrate using the micro electrodes, and the frequency modulation is used to detect the capacitance change of the conductive electrode. One way to combat EMI is to achieve the touch controller “smart” frequency scanning function. Work frequency 0.7-mhz and 2.2-mhz to identify and avoid the environment “noise”, otherwise it will prevent the detection of touch events.
The most critical issue in the response time of the 4K resolution touch operation is the combination of the UHD display touch screen function. This is a challenge for all touch technology, and now the typical HD display touch screen pixel is about 120 Hz refresh rate. The required control data processing needs a large number of pixels and (> 8 million) in the UHD display means that the latest 4K practical operation in 60Hz or less; this makes it challenging to handle real-time touch events, such as drag on the screen cursor, because the display board processing ability is the background image effectively be refreshed. So the UHD screen mobile touch is like a line, there are traces of the finger than high-definition display obvious, and even the P-CAP touch screen delay will be in the speed of the touch event report.
Of course, this delay in the ordinary watch (no touch) is unknown because the viewer has no reference to measure it’s frame. Dynamic touch applications require drawings or fast objects; however, the delay of the 4K system is obvious compared to the current HD type touch screen.
With the new 4K monitor entering the market, the higher refresh rate and the potential to improve the driving circuit to reduce the EMI, these problems will be reduced. But before this, the influence of the touch controller’s selection and touch application on the user experience should be carefully considered in the UHD display.