Lasers are divided into four safety levels. Different levels cause different hazards to the human body, and the protection standards for lasers are also different.

I think everyone is silly and confused about LED and LD.

The light-emitting principle of the laser diode: The P-N junction in the laser diode is formed by two doped gallium arsenide layers.

A blue laser diode is a semiconductor laser that can generate a concentrated photon beam with a wavelength of about 400 to 500 nanometers (the visible electromagnetic spectrum region considered blue or violet by the human eye).

The color of light is determined by the wavelength (or frequency) of the light. A certain wavelength corresponds to a certain color.

The laser diode has three pins: LD transmitting terminal, PD receiving terminal, LD-N common terminal