A strong up and coming technology is capacitive sensing. As we getting more and more used to touchscreens behind glass (mobiles, tablets, etc.), switching behind glass attracts the interest of the industry. If one takes into account the possibilities switching behind a cover lens gives, it is clear that capacitive sensing technology is recognized as future proof. With the glass examples we have produced we have demonstrated the following advantages:
● Easy to clean
● Highly decorative solutions including full colour printing (both transparent and light blocking)
● Backlight options
● Death fond printing options
● Integration of displays and insert labels behind the glass
Many applications still use membrane switch technology which is based on polyester graphical overlays with a switching layer underneath. This technology is not suitable to be used with a glass cover lens. Capacitive sensing is the solution to overcome this problem. With the use of a sensing layer and a microcontroller we can operate switches behind glass or other surfaces. This Technology is known within SCHURTER as CapKey®.
One of the essential components within a CapKey® solution is the sensor. The sensor can be made of polyester or directly tracked on a PCB. The tracks and layout of the sensor is essential for good functionality. Transparent switch areas are possible with the use of conductive transparent material (ITO). The sensor itself will be laminated behind the chosen cover lens material. Each sensor requires a connection tail made of polyester or Kapton material. As the sensors are made by a screen print process, sensors can be produced in any required size and shape. This will give you similar design freedom as a traditional membrane switch.
Unlike PCAP touchscreens with limited number of available controllers, there are many different kind of CapKey® controllers on the market. SCHURTER has selected, based on experience and knowledge, a preferred list of CapKey® controllers. These controllers are from well known manufacturers like Atmel, Microchip, Cypress and Freescale. Each controller has its own unique set of features and specifications. Before we can help you with the design of the correct sensor and selecting the corresponding controller, a decision has to be made of the required features like:
- Number of keys
This set of features will determine the best suitable controller and the required sensor design. SCHURTER will keep the focus on their core business of producing and assembling the sensors and cover lens. Regarding the controller you can choose the SCHURTER organization to take care of this or we can provide the schematics, BOM and libraries to integrate the CapKey® controller onto your own PCB. Please contact us to learn more how SCHURTER can help you with the design of the CapKey® controller.
Specification sheet CapKey:
CapKey products are relatively new in the industry. They can replace membrane switches and easily combine with a PCAP touchscreen. They are also perfectly suitable to make equipment with a modern look and feel. It also introduces new features like sliders and wheels. An ideal technology for state of the art medical equipment.