EMR stands for Electro Magnetic Resonance Technology. Touch screens using this technology are also known as electromagnetic touch screens. Unlike capacitive or resistive screens, in EMR the basic principle is to transmit electromagnetic signals through an electromagnetic pen and interact with the electromagnetic sensor board behind the display screen. When the electromagnetic pen is close to the touch screen, the electromagnetic induction board behind it, which contains an array of horizontal and vertical antenna will sense the signal from the pen due to magnetic flux change. By calculating the change, the X and Y coordinate of the pen's position can be determined.
Since the electromagnetic pen has a longitudinal pressure sensor, when the user writes through the pen, pressure is transmitted to the pressure sensor through the tip. The changing pressure will cause the electromagnetic signal emitted by the pen to change accordingly. The electromagnetic induction board therefore can sense the pressure change. This pressure-sensing feature is especially useful in high-accuracy handwriting and drawing application.