The principle of stylus is to locate by infrared ray and ultrasonic wave. When the tip of the stylus is pressed, it will emit ultrasonic waves and infrared rays, because there is a transmitter at the upper end of the stylus.

Touch screen pens can be roughly divided into resistive touch screen pens and capacitive touch screen pens, which are suitable for resistive and capacitive touch screen terminals respectively.

Stylus type:

1, resistive stylus

The resistive touch screen mainly realizes the operation and control of the screen content through the principle of pressure sensing, so the resistive stylus only needs to ensure that it can provide enough pressure, and most ordinary stylus can also meet the requirements.

2, capacitive touch screen pen

Capacitive touch screen technology works by using human body's current induction, so capacitive stylus must be made of conductive materials and have conductive characteristics. When the stylus touches the capacitive touch screen, the human body will form a coupling capacitance between the stylus and the surface of the touch screen.

For high frequency current, the capacitor is a direct conductor, so the stylus draws a small amount of current from the contact point. This current flows out from the electrodes at the four corners of the touch screen, and the current flowing through these four electrodes is proportional to the distance from the finger to the four corners. The controller can accurately calculate the ratio of these four currents, so as to get the position of the touch point.