Many consumers are interested in three-dimensional (3-D) technologies that make display images as real as possible. In response, a number of fairly mature 3-D technologies have already been introduced in various studies. Among them, we reviewed the integral imaging system and the multiview system, which can realize 3-D, from the past to the present. Those systems, however, suffer from problems such as depth range, two-dimensional (2-D) and 3-D conversions, and 3-D resolution. Therefore, a liquid lens is proposed as a technique to resolve the drawbacks. Using a liquid lens with variable focal length, the depth range was enhanced using a time-division multiplexing technique in an integral imaging system, and the function of 2-D and 3-D switching was enabled in a multiview system. Furthermore, methods were introduced to solve the problems of 3-D resolution reduction in multiview systems and vergence–accommodation conflicts in VR systems.