A projection display apparatus includes a light source configured to emit a first light, a reflective light modulator configured to modulate the first light to form a second light conveying a rendered image, a polarizer and a light guide plate. The light guide plate can include a plurality of optical elements embedded in the thickness of the light guide plate or provided on an outer surface of the light guide plate. An illuminating light entering the light guide plate can be redirected toward the light modulator by reflection at the grooves or optical elements. Moreover, an image light from the light modulator can travel through the light guide plate to the polarizer.