Patent ID: 6373638
Filing Date: 2002-04-16
Classification: G02B

Abstract:
An image taking optical system comprising:a main optical system for forming an object image; and a reduction optical system including a plurality of lenses for reduction an image without re-forming the image formed by the main optical system, wherein the lens having the strongest positive optical power within the reduction optical system satisfies the following conditions: âˆ’2.51.2â€ƒwherein the lens having the strongest negative power within the reduction optical system satisfies conditional equations; 0.65âˆ’5.5where rP1 represents the radius of curvature on the object side of the positive lens, and rP2 represents the radius of curvature on the image side of the positive lens, rN1 represents the radius of curvature on the object side of the negative lens, and rN2 represents the radius of curvature on the image side of the negative lens, &phgr;P represents the optical power of the positive lens, &phgr;N represents the optical power of the negative lens and &phgr;s represents the optical power of the total system of the reduction optical system.