PROJECTION OPTICAL SYSTEM AND HEAD-UP DISPLAY

A projection optical system includes an eyepiece optical system configured to refract and reflect a light emitted from an image forming unit for forming image information to display a virtual image, wherein the eyepiece optical system includes at least a concave lens, a folding mirror, and a concave mirror which are successively placed in order from the image forming unit including a liquid crystal display panel. The projection optical system configured as above is provided on a head-up display.