Patent attributes
A projection device adapted to be placed on a vehicle and a control method of the projection device are provided. The projection device includes a storage device storing image data of at least one projection image, a projection module, a distance detection device measuring a projection distance from the distance detection device to a projection plane, and a control device electrically connected to the storage device, the projection module, and the distance detection device. The control device enables the projection module to project the projection image and controls brightness or size of the projection image according to the corresponding projection distance. The projection device is activated by opening a door of the vehicle, and power of the projection device comes from the vehicle. The projection image can be adjusted according to the projection distance to maintain stable brightness and the size of the projection image.