A heads-up display system includes a liquid crystal display unit that can
change optical characteristics in accordance with a video signal. The
light modulated by the liquid crystal display unit is projected on a
surface of a transparent plate that can reflect the light so as to
realize a projection display. The light projected on the transparent
plate is polarized light having a transmission axis extending in a
direction parallel to a line defining the center with respect to incident
light and reflective light of the transparent plate.