Patent ID: 8814365

Claim:
An optical device comprising: a light synthesis prism that synthesizes incident light beams which are incident to a plurality of incidence surfaces and outputs the synthesized light beams; a light modulation unit that includes an optical compensation element and a reflective light modulation device; and a fixing member that fixes a reflective polarization element and the light modulation unit to the light synthesis prism so as to correspond to one of the incidence surfaces, wherein the light modulation unit includes a light blocking member that blocks light from reaching the light modulation unit and limits light with which the optical compensation element and the reflective light modulation device are irradiated, to light passing an aperture portion; and a heat insulating member that comes into contact with the light blocking member and the fixing member, wherein the light blocking member includes: a heat insulating member contact portion that comes into contact with the heat insulating member; and a light blocking portion that has the aperture, and wherein the light blocking portion and the heat insulating member contact portion have a step difference of a predetermined height.