A device for generation of three-dimensional images in the observer's eye using at least one two-dimensional display and an optical system with an adjustable focal length. The display generates planar images corresponding to the different depths of the designed three dimensional (3D) image and the images are then directed to at least one mirror or lens with the adjustable focal length synchronized to the particular image. The optical system generates virtual images at different virtual planes in such a way that the eye receives a complete 3D virtual image.