Achromatic Phase Retarder with Anisotropic Layered Structure

摘要

A phase retarder including a transparent substrate; and at least a symmetrical or pseudo symmetrical film stack stacked on the transparent substrate, the symmetrical or pseudo symmetrical film stack having odd numbers of thin film, the odd numbers of thin film having an intermediate thin film located at the center of the symmetrical or pseudo symmetrical film stack and at least one thin film located respectively on two sides of the intermediate thin film, and, with respect to the central thin film, properties of the thin films located respectively on two sides of the intermediate thin film are symmetrical or pseudo-symmetrical, there is at least one anisotropic thin film in the symmetrical or pseudo symmetrical film stack.