Patent ID: 8118437

Claim:
An optical device comprising: a light source; a light modulation device that modulates a light beam emitted from the light source to an image light in accordance with image information; a projection optical device that magnifies and projects the image light; and a retention member configured to hold the light modulation device and the projection optical device, including: a projection optical device attachment section for attaching the projection optical device, and a light modulation device attachment section provided for attaching the light modulation device with a protrusion to a side opposite to the projection optical device along an optical-axis direction of the projection optical device, wherein: the projection optical device attachment section includes: a fixing section that fixes the projection optical device substantially at a position of the center of gravity; a support section that is disposed opposing the fixing section in the optical-axis direction, and supports the light modulation device attachment section such that the light modulation device attachment section is fixed to a side of the support section that is opposite the fixing section in the optical-axis direction; and a connection section that connects together the fixing section and the support section, the support section is formed with a concave section, and the light modulation device attachment section is formed with a collar section, the collar section being fixed to at least two places of both sides of the concave portion by screw.