Patent ID: 7775667

Claim:
An optical device comprising: a plurality of optical modulation devices which modulate an incident luminous flux in accordance with image information; an optical element provided on a luminous flux irradiation-side of each optical modulation device which optically converts the luminous flux emerging from each of the optical modulation devices; a prism having a plurality of luminous flux incidence surfaces positioned on a luminous flux irradiation-side of each optical element, the prism forming an optical image by synthesizing a luminous flux emerging from each optical element; a holding member which holds at least one of the plurality of optical modulation devices; and a pair of light-transmissive substrates which sandwich the optical element, the pair of light-transmissive substrates comprised of an incident-side substrate disposed on a luminous flux incident-side of the optical element and an irradiation-side substrate disposed on the luminous flux irradiation-side of the optical element, wherein the irradiation-side substrate has a dimension larger than that of the optical element and includes an upward extending portion which extends above the one of the luminous flux incidence surfaces and a downward extending portion which extends below the one of the luminous flux incidence surfaces, and is secured to the one of the luminous flux incidence surfaces of the prism, and the holding member has an aperture through which the luminous flux emerging from the optical modulation device passes, the holding member secured to the prism by being affixed to a surface of the upward extending portion and the downward extending portion of the irradiation-side substrate so as to cover the optical element.