Why do three-color laser projectors speckle?


Many people say that speckle appears when using a three-color laser projector, so when watching a movie, the screen will feel a clear frosted feeling. Why does the three-color laser projector have speckles and a matte feeling?


Most of the three-color laser projectors use RGB pure laser light sources, so they have the characteristics of high brightness, pure color and strong coherence. Too strong coherence will affect the quality of the picture. Therefore, the reasons for speckle in three-color laser projectors are as follows.

1. The laser light source is used, and the laser light source is a coherent light source;

2. The laser is monochromatic light, and the frequencies of multiple laser beams separated by the same laser are the same;

3. Microscopically, the screen is uneven, and the laser hits the uneven screen to produce a constant phase difference;

4. The direction of the laser reflected from the screen to the observation point is also the same.

Why do three-color laser projectors speckle.jpg

When the three-color laser projector is projected on the screen, it is reflected or transmitted to the human eye through the screen. It uses pure laser light as the light source, which produces disordered interference on the screen, forming random and countless bright and dark spots, resulting in speckle.