1. Laser diode excites electrons and generates laser radiation by injecting current into semiconductor materials. The working principle of laser diode is similar to that of laser, and it has the characteristics of clear orientation, good monochromaticity and high brightness, while light-emitting diode releases energy by injecting current into semiconductor materials, and generates optical radiation by combining electrons and holes, but the optical radiation generated is not laser, but broad-spectrum light.
2. The laser diode outputs a highly focused laser beam. On the contrary, the light emitting diode outputs scattered light with a large beam angle. The beam of laser diode is monochromatic, coherent and focused, while the light radiation of light-emitting diode is polychromatic and scattered light with large observation angle.