Projected capacitive touch screens (PCAP)
Two different types of touch systems are available: resistive touch and capacitive touch. Resistive touch systems react to pressure and can be operated with any object. With capacitive touch systems, the voltage field is changed by a conductive object.
In projected capacitive touch screens, two isolated planes are used as a sensor and driver. In addition, a conductive pattern is created in a strip or diamond shape. If a finger or other conductive object hits one of these intersections, the capacitor's capacitance will change. This technology can also be used for gesture control and multi-touch. The sensitivity of the system must be adjusted depending on the conductivity of the objects used or if gloves are worn.
How is calibration performed?
You send us the gloves you use and tell us whether the panels will come into contact with water or other liquids. External factors like these play a major role in the calibration process. We then test the behaviour of the touch system under the defined surrounding conditions. We evaluate the raw data of the touch controller, adjust the settings and increase the signal strength if necessary. This procedure is particularly important if thick gloves are worn, as most glove materials are poor conductors, which increases the risk of a touch operation error. In a capacitive touch system, the sensors react to the conductivity of human fingers, and this response reduces in line with the thickness of the gloves worn. With thicker glovers, the voltage field needs to be stronger and the sensors more sensitive, so the signal strength is increased. Separate tests must be carried out for each type of glove, as there is no universal setting. If the touch system also comes into contact with water or other conductive liquids, these factors must also be taken into account during calibration.
The trick is to ensure operability on the one hand and system stability on the other, avoiding any false triggering that could negatively influence machine operation.
The system, which is perfectly configured to suit your requirements, is tested directly in live operation under real environmental influences to ensure smooth functionality.
In many sectors, including pharmaceuticals and wider industry, employees are required to wear gloves in the workplace, which greatly affects the operation of the touch system. Touching the screen with water and other liquids will also affect the system.
For smooth operation of the touch panel, it is important to adjust the entire touch system to the surrounding conditions—such as the presence of liquids, severe temperature fluctuations or electromagnetic interference—in addition to configuring the sensitivity level to take factors such as thick gloves into account.
We can support you through this process, drawing on our experience in the custom calibration of touch systems.