A display includes a light source, a first color wheel, a second color wheel, an actuator, a controller, and a light modulator. The light source is for providing a light beam. The first color wheel includes plural primary-color filtering areas, and the second color wheel includes plural left or right eye filtering areas. The actuator rotates the first color wheel and the second color wheel. The controller is for controlling the rotations of the first color wheel and the second color wheel, such that the light beam passing through the first color wheel and the second color wheel is filtered to plural left or right eye primary-color light beams with different spectra. The light modulator is for modulating the left or right primary-color light beams and projecting the modulated left or right primary-color light beams onto a screen to display an image.