Patent ID: 9523907
Filing Date: 2016-12-20
CPC Classification: G02B,G03B

Claim Text:
1. A zoom optical system comprising, in order from an enlargement conjugate side to a reduction conjugate side: a first optical group; and a second optical group having a zoom function, wherein the zoom optical system is configured to conjugate an enlargement conjugation point on the enlargement conjugate side with an intermediate imaging position located between the first optical group and the second optical group, and to conjugate the intermediate imaging position with a reduction conjugation point on the reduction conjugate side, wherein the second optical group includes, in order from the enlargement conjugate side to the reduction conjugate side, a lens unit B wherein the lens unit B is satisfied, where fR represents a focal length of the second optical group in a wide-angle end, and fB22 represents a focal length of the lens unit B