We can view it as a video screen, so with it, we can increase the safety when driving, and see the rear more clearly when reversing, helping drivers drive better. We can also find that there are some door lock actuators in it, which can lock or open the door through the driver's command, and there are also some electromagnetic or DC electromotive force driving modes in it. With such a structure, some movement directions can be changed to achieve some special automation results, so it also makes the car more intelligent.