Patent ID: 7114811

Claim:
An optical assembly, comprising: an optical unit for a predetermined color having a transmissive optical modulation element that is illuminated by illumination light; a first polarizing plate disposed directly opposite an incident side of the optical modulation element; a second polarizing plate disposed on an emission side of the optical modulation element; an optical compensation element disposed between the optical modulation element and the second polarizing plate, a clip portion pressing the optical compensation element by a predetermined force; a holding member to hold the optical compensation element so as to allow adjustment of a rotational position thereof about an optical axis, the holding member including: a movable frame to fix the optical compensation element; a main body member to house the movable frame and support the movable frame rotatably about the optical axis via a pivot shaft; and an adjusting screw to adjust a predetermined portion provided in a periphery of the movable frame to fix the movable frame to the main body member in a direction perpendicular to the optical axis; and a light combining device that is disposed on the emission side of the second polarizing plate assembled in the optical unit and that combines image light from the optical unit for the predetermined color and image light of another color and emits the combined image light, the movable frame detachably fixing the optical compensation element, and the movable frame holding the optical compensation element slidably in a lateral direction perpendicular to the optical axis in response to a predetermined or greater force, thereby allowing the optical compensation element to be detachable.