Abstract: A micromirror array lens consists of many micromirrors with two degrees of freedom rotation and one degree of freedom translation and actuating components. As a reflective variable focal length lens, the array of micromirrors makes all lights scattered from one point of an object have the same periodic phase and converge at one point of image plane. As operating methods for the lens, the actuating components control the positions of micromirrors electrostatically and/or electromagnetically. The optical efficiency of the micromirror array lens is increased by locating a mechanical structure upholding micromirrors and the actuating components under micromirrors. Semiconductor microelectronics technologies can remove the loss in effective reflective area due to electrode pads and wires. The lens can correct aberration by controlling each micromirror independently. Independent control of each micromirror is possible by known semiconductor microelectronics technologies.