Light emitting diode display panel

A writing device, comprising:

• a lighting pen;
• and
• a light emitting diode display panel, comprising:
• a control circuit;
• and
• a plurality of pixels arranged in a matrix, each of the pixels comprising a first light source and a first light sensing element, the first light sensing element receiving a first optical signal from the lighting pen and generating a first control signal to the control circuit, according to the first control signal, the control circuit turning on the first light source in the pixel;
• wherein the pixels further comprise a first polarizer covering the first light sensing element, when the lighting pen emits the first optical signal, a polarization direction of the light from the lighting pen is parallel to a polarization direction of the first polarizer, therefore, the first optical signal can pass through the first polarizer and be received by the first light sensing element.