PURPOSE: To improve the picture quality such as colors of a color image and obtain an excellent composite image by providing a converting member which changes the direction of polarized light on the incidence or projection side of a liquid crystal display panel.

CONSTITUTION: Respective liquid crystal display panels 2-4 for red. green, and blue which are arranged nearby a dichroic prism 1 are all placed in the same polarization state, namely, the transmission axes of respective polarizing plates are all set to the direction of S-polarized light; and a wavelength plate 14 is arranged on the projection side of the liquid crystal display panel 3 for green. Consequently, the light from a light source 5 is divided by dichroic mirrors 6 and 7 and total reflecting mirrors 8-12 into three kinds of red, green. and blue to only irradiate the respective liquid crystal display panels 2-4. Therefore, the need to divide the light from the light source 5 into a P-polarized light component and an S-polarized light component and irradiate the respective liquid crystal display panels 2-4 is eliminated, the optical paths from the light source 5 to the respective optical display panels 2-4 are made simple, and restrictions on the optical path design are reduced to facilitate the optical path design and increase the degree of freedom.