To provide an optical assembly capable of enhancing black level display while preventing deterioration of a WV film, and a projector assembled therewith, optical compensation elements are disposed before and after liquid crystal light valves, so that an unintended phase difference generated on the incident and emission sides of the liquid crystal light valves for individual colors is eliminated by adjusting the rotational positions of the optical compensation elements, thus enabling an enhancement in the contrast of a color image displayed on a transmission screen member. In case of B light including ultraviolet light in part, the optical compensation element is disposed at the subsequent stage of the liquid crystal light valve, so that as compared with when the optical compensation element is disposed at the preceding stage of the liquid crystal light valve, the optical compensation element can be reduced or prevented from deteriorating with age, thus enabling the contrast of image display to be maintained over a long period of time.
