IMAGING OPTICAL SYSTEM, IMAGE PROJECTION OPTICAL SYSTEM AND IMAGE PROJECTION APPARATUS

摘要

The imaging optical system makes magnification conjugate side and reduction conjugate side predetermined positions conjugate to each other and forms an intermediate image conjugate to both the predetermined positions. The optical system includes a magnification side positive lens as a first lens disposed on the magnification conjugate side further than an intermediate imaging position, a reduction side positive lens as a third lens disposed on the reduction conjugate side further than the intermediate imaging position, and a negative lens as a second lens disposed between these positive lenses. Conditions of 5<ν2−ν1<80, 5<ν2−ν3<80, 0.03

主权项

1. An imaging optical system configured to make a predetermined position on a magnification conjugate side and another predetermined position on a reduction conjugate side conjugate to each other and to form an intermediate image conjugate to both the predetermined positions, the optical system comprising:
a magnification side positive lens disposed on the magnification conjugate side further than an intermediate imaging position where the intermediate image is formed and being convex toward the magnification conjugate side, the intermediate imaging position being located between two points at both of which an off-axis principal ray of a light flux entering the optical system intersects with an optical axis of the optical system; a reduction side positive lens disposed between the two points and on the reduction conjugate side further than the intermediate imaging position and being convex toward the reduction conjugate side; and a negative lens disposed between the magnification side positive lens and the reduction side positive lens, wherein, when the magnification side positive lens, the negative lens and the reduction side positive lens are referred to as a first lens, a second lens and a third lens, respectively, the following conditions are satisfied:
5<ν2−ν1<805<ν2−ν3<800.03