An achromatic quarter-wave film using one twisted-nematic liquid-crystal (TNLC) cell, a chromatic half-wave plate, and a chromatic quarter-wave plate is presented. The Jones matrix is used to calculate the optical properties of the system. An optimal algorithm is used for optimizing the configuration parameters. Simulation results indicate that the designed configuration is capable of turning a linearly polarized light into perfectly circularly polarized light in the wavelength range 400-700 nm. The manufacturing tolerance of the cell gap and twisted angle of the TNLC are good.