Surface Capacitive Touch
What is RRFC™ (Reversing Ramped Field Capacitive) Touch Technology?
The touchscreen is very similar in operation to the legacy (existing) surface capacitive touch technologies manufactured by others today. However, the CapPLUS touchscreens manufactured by Wacom not only provide several physical improvements over these existing capacitive screens, but with the unique performance features of Wacom’s new RRFC™ touch technology embedded in their own patented controller, many new opportunities and markets are opened up to this revolutionary technology.
The sensor (touchscreen)
One area of re-design, critical to the enhanced performance that CapPLUS offers is in the high-precision border designs which make CapPLUS accurate right up to the edge of the active area, even in screen sizes of 46” and larger. In addition, Wacom will:
- Use ITO (Indium-Tin-Oxide) coatings in addition to ATO. ITO-based coatings have better optical properties but higher power consumption and is the standard for product aimed at AC-powered applications.
- Provide a hardcoat that is 4X thicker than the coatings typically used by current manufacturers without optical degradation thus reducing risk of damage from scratching
- Provide the option of specialty hardcoats with extra hardness and other coating and bonding services to enhance optical properties
- Provide custom sensor border trace and tail designs that can enable even a flush-to-the-glass-edge user surface.
The Controller
The unique performance features of Wacom’s CapPLUS touch technology are embedded in the revolutionary controller electronics. The controller generates an AC voltage which is applied to two adjacent corners and a DC voltage that is applied to the other two corners. This creates a linear voltage across the conductive surface as well as a corresponding ramp-shaped electro-static field.
The controller then switches the signals around all the corners (four possible combinations) and current flow is measured in each case. So, there are effectively two measurements, thus two views on the actual touch location in each axis. As with legacy surface capacitive screens, the changes detected in the current flow are proportional to the position of touch. With other unique features of the Wacom RRFC™ controller, the results of all the corner combinations are checked and certain currents that are related to system componentry can be cancelled out.
A much purer signal that represents the actual touch event in each axis emerges that is independent of signal level strength.
The RRFC™ controller then does a significant amount of digital signal processing to further tune the signal to actively compensate for several other factors that can affect system accuracy and drift such as temperature and humidity.
With this technology, many legacy problems with capacitive touch technology such as temperature drift and issues with metal kiosks and bezels are a thing of the past!
