Patent ID: 7911411

Claim:
A projection apparatus comprising: a light tunnel of square tube shape configured to pass light emitted from a light source and change the light to condensed uniform light; a mirror configured to reflect the light passed through the light tunnel; a DMD (Digital Micro-mirror Device) configured to reflect the light at an image forming surface irradiated with the light reflected by the mirror and form an image; a lens configured to project the image formed with the DMD; a frame on which the light tunnel, the mirror, the DMD, and the lens are supported; and a rotation adjustment fixing mechanism comprising: a base rotatably supported on a supporting part formed on the frame at one surface side of the base so that, when an incident port of the light tunnel faces the light source and an exit port faces the mirror, a rotation axis of the base is aligned with a central axis of the light tunnel, the light tunnel being fixed at an opposite surface side at the center of the base with a fixture; a plurality of pins configured to swingably support one end of the base, each of the plurality of pins being passed through a plurality of holes formed at the one end of the base in a direction perpendicular to the central axis of the light tunnel and attached to the frame; a spring arranged around each pin and configured to press an inclined surface of the base formed so as to incline in an axial direction of the light tunnel around each hole of the base towards the supporting part side of the frame; a first screw passed through a hole formed on the other end of the base in a direction perpendicular to the central axis of the light tunnel and screwed into a screw hole formed on the frame, the first screw being configured to press the other end of the base towards the supporting part of the frame with a head; and a second screw screwed into a screw hole formed on the other end of the base to be passed through the base so that an inclined part formed at a distal end of the second screw engages with an inclined surface formed on the frame, the inclined part formed at the distal end of the second screw being parallel to the inclined surface of the frame, and the second screw being configured to press the base against a side wall of the frame in the axial direction of the light tunnel, wherein the rotation adjustment fixing mechanism adjusts a rotation angle of the base and fixes the light tunnel to the frame by changing the screw-fit depth of the first screw with respect to the screw hole of the frame and screwing the second screw into the screw hole of the base so as to engage with the inclined surface of the frame.