Patent attributes
A projection optical system includes: a first optical system and a second optical system disposed in that order from an enlargement side. The second optical system forms an intermediate image of the image, and the first optical system enlarges and projects the intermediate image. The first optical system includes: a first lens group, a first reflecting optical element, and a part of a second lens group, disposed in that order from the enlargement side. The second optical system includes: a remainder of the second lens group, a second reflecting optical element, and a third lens group, disposed in that order from the enlargement side. The second reflecting optical element reflects light output from the third lens group toward the second lens group. The first reflecting optical element reflects light output from the second lens group toward the first lens group.
