Patent ID: 7520621

Claim:
A manufacturing apparatus of an optical device that is used for a projector, the optical device including a plurality of optical modulators that respectively modulate each of a plurality of color lights in accordance with image information; and a color-combining optical device that combines the color lights modulated by the optical modulators to form an image light, the projector including a projection optical device that is disposed on a downstream of an optical path of the optical device and projects the image light formed by the optical device in an enlarged manner, the manufacturing apparatus, comprising: a holding unit that holds the color-combining optical device at a predetermined position; position adjusters that respectively hold the optical modulators and adjust positions of the optical modulators relative to the color-combining optical device; dimension-measuring units that measure an external dimension of the color-combining optical device in an optical-axis direction; and a controlling unit that drives the position adjusters, wherein the controlling unit includes: a storage that stores distance information relating to a back-focus distance defined in accordance with specifications of the projection optical device; a deviation-amount calculating unit that calculates a deviation amount of an optical path length of a light beam from the optical modulator to the projection optical device when the color-combining optical device is interposed between the optical modulator and the projection optical device based on the external dimension of the color-combining optical device in the optical-axis direction measured by the dimension-measuring units; a back-focus-position calculating unit that calculates a back-focus position of the projection optical device in correspondence with a deviation of the optical path length based on the distance information stored in the storage and the deviation amount of the optical path length calculated by the deviation-amount calculating unit; and a drive controller that drives the position adjusters and positions the optical modulators at the back-focus positions of the projection optical device in correspondence with the deviation of the optical path length calculated by the back-focus-position calculating unit.