Method for compensating electromagnetic inductive pressure level

A method for establishing a pressure level compensation value table for an electromagnetic pen, comprising:

• providing an electromagnetic pen with a standard or predetermined frequency and a standard or predetermined signal amplitude on a touch panel, wherein the touch panel has a sensor layer and at least one sensor coil on a transparent substrate, the sensor coil is located on the peripheral region of the transparent substrate and around the sensor layer;
• measuring signal amplitudes of the electromagnetic pen on predetermined locations on the touch panel;
• calculating distances between the electromagnetic pen and the sensor coil by calculating the differences between the measured signal amplitudes and the predetermined signal amplitude;
• measuring frequencies of the electromagnetic pen on the predetermined locations on the touch panel;
• and
• establishing a pressure level compensation table via obtaining frequency error values of the predetermined locations by calculating the differences between the measured frequencies of the electromagnetic pen on the predetermined locations and the standard frequency.