Disclosed is a projection display device that displays an image using a coherent light source. In the projection display device, a liquid crystal scattering element comprising a liquid crystal layer held between two light transparent substrates is disposed.The liquid crystal layer is formed of a liquid crystal mixture composed of a liquid crystal composition and 0.005 to 1.0% by weight of an ionic compound added to the liquid crystal composition.Upon the application of a low-frequency rectangular wave voltage across the liquid crystal layer, light passed through the liquid crystal layer is scattered to eliminate the coherence and thus to reduce speckle noises.
