There are two main digitizer technologies: Electromagnetic Resonance (EMR) and Active Electrostatic (AES). We covered the basics of each in our last active pen explainer, now let’s take a look at their strengths and weaknesses.
You’ll find Wacom’s EMR technology in is professional-caliber devices, including Cintiqs and the Wacom Mobile Studio Pro line, complete with marketing and prices targeted at professional artists and designers.
One key EMR advantage: it’s significantly cheaper to produce a large pen display, than it is a capacitive touch-based AES pen display. Another is that the two separate digitizers (as described in the previous Wacom and N-trig article) eliminate any delay or hesitation in registering the input signal. EMR devices can quickly discern between pen and touch inputs, and this makes for a very smooth pen experience, which translates to being better professional art devices.
AES Good Enough, Too
AES devices are also good enough for artists and designers, though require some getting used to and compensation. There are plenty of artists using Wacom AES or N-trig DuoSense 2 digitizer/pen combo devices. The success of the Microsoft Surface Pro line and the various Lenovo ThinkPad tablets and 2-in-1s is evidence.
AES also has significant performance advantages over EMR. Due to the location of the resonance coil in the pens, the EMR experience is marred by cursor drift (the distance between the pen tip and the actual cursor location, which can vary depending on the angle of the pen tip). AES does not suffer from this problem, since the digitizer reacts to the conductive pen tip.
EMR devices also suffer from parallax. This is similar to cursor drift, but is caused by the distance between the digitizer board (under the LCD) and the actual display glass. Device makers can mitigate the parallax effect somewhat by bonding the display glass directly to the LCD, and many do just that.
Because AES devices have a much shorter distance between the pen tip and touch-panel bonded glass, they do not suffer from parallax issues.
Yet another performance problem for EMR is edge drift, or jitter. This problem arises at the display edges. EMR’s precision depends on the coil radiating it’s location back to the digitizer board 360 degrees outward. Near the edge of the board, this interaction is limited to only 180 degrees from pen’s touchpoint. Corners are an even bigger problem, with only 90 degrees.
This manifests itself with a drifting or jittery cursor, which has trouble pinpointing the locations.
Again, AES devices don’t suffer from this issue as severely, since AES uses the physical touchpoint of the pen tip to the surface to determine location.