Compact optical system displaying mid-air images movable in depth by rotating light source and mirror

Mid-air imaging technology enables computer graphics (CG) images to move around in the real world. However, the big form-factor of large-format mid-air displays makes them bulky and limits their applicability. To reduce the size of such displays, we propose an optical design that realizes mid-air image movement by rotating the reflecting surface and the light source with motors and thus moving the virtual image of the light source. We made a prototype based on the calculation of the mirror and display angles and the distance between them and evaluated the luminance, sharpness, and position of the mid-air image of this prototype. We confirmed that the size of the prototype was smaller than that produced by the previous method, which will allow a smaller form-factor for creating mid-air images for different applications.