A display system requiring no special glasses is a useful technology for 3D images. In this paper, two types of real- time 3D displays using a holographic screen instead of a lenticular screen are described. One is a stereoscopic 3D display system with viewing apertures such as conventional two-step holographic stereogram. The other is a stereoscopic 3D display system based on a reconstruction of parallax- rays. These systems consist of a liquid crystal device and a holographic screen formed on holographic optical elements. These systems can construct animated 3D images in real-time by updating LCD pixels.