a projection - type liquid - crystal display in which a fresnel lens in placed on the exit side of the liquid crystal panel to focus the image toward a projection lens . preferably , the fresnel lens has a non - symmetric pattern so as to efficiently gather light propagating through the display panel at an oblique angle coinciding with a reorientation angle of the liquid crystal . additional optics on the incident side of the panel , perhaps including another non - symmetric fresnel lens , collimates the light at the oblique angle .