A three-dimensional display device includes a two-dimensional display displaying a depthwise image, and a variable focal length micromirror array lens receiving light from the two-dimensional display and forming a corresponding image in the required location in space. Each depthwise image represents a portion of an object or scene having the same image depth, and the two-dimensional display displays one depthwise image at a time. The focal length of the variable focal length micromirror array lens changes according to the depth of the depthwise image being displayed. The variable focal length micromirror array lens has enough speed and focusing depth range for the realistic three-dimensional display.