DISPLAY DEVICE, DISPLAY SYSTEM, AND MOBILE OBJECT

A display system A includes a light deflector that scans the light beams that are emitted from a light-source device in the main scanning direction and the sub-scanning direction orthogonal to the main scanning direction to form an intermediate image on a screen , the screen that disperses the light, a front windshield that reflects the diverging light diverging from the screen , and a free-form surface mirror that projects the diverging light diverging from the screen towards the screen to form a virtual image . The screen is arranged so as to satisfy the condition in the following equation: S*O*(M+O)/(T*E*M)≤1.95 where S denotes distance between a location of eyepoint of the viewer of the virtual image and the virtual image, E denotes distance between the location of eyepoint of the viewer of the virtual image and an image forming optical system that uses the diverging light to form the virtual image, M denotes distance between the light deflector and the intermediate image, and O denotes distance between the intermediate image and the image forming optical system, and T denotes distance between the virtual image and the image forming optical system, where each distance indicates length of an optical path that passes through a center of an image formed by the light when an object is observed from a reference eyepoint.