When we need to diffuse or concentrate the light source from a simple point, we use a reflective lampshade. For example, the reflective umbrella used in photography is to turn the light source into a single surface, and the lampshade of a car headlight is to make the light source become a column and propagate horizontally forward. The shadowless lamp on the operating table can also be seen as concentrating many light sources from different directions to a single point.
Official WeChat