Patent attributes
A first optical system, a first mirror, a second optical system, a second mirror, and a third optical system are disposed in order on an optical axis from an image forming panel to a screen. A first optical axis of the first optical system, a second optical axis of the second optical system, and a third optical axis of the third optical system are formed in a U shape, and orientations of luminous fluxes of the first optical axis and the third optical axis are reversed. The first mirror, the second optical system, the second mirror, and the third optical system are held to make a second holding barrel with respect to the first optical system. The second holding barrel is rotationally moved in a rotational movement range of 45° with respect to a first holding barrel. In projecting portrait image instead of a landscape image, the second holding barrel is rotated in increments of 45° with respect to the first holding barrel.
