JP2004295112A5 - - Google Patents

Claims (8)

In order from the object side, a first positive meniscus lens having a convex surface facing the object side, an aperture stop, a second negative meniscus lens having a convex surface facing the image side, and a third positive lens are arranged. An imaging optical system in which the object side surface of the lens is an aspheric surface whose curvature decreases toward the periphery, and the image side surface thereof is an aspheric surface whose curvature increases toward the periphery. 2. The imaging optical system according to claim 1, wherein the following condition (1) is satisfied.
(1) −100 <(r1r ² / f1) / (r2f ² / f2) <− 1
Where r1r is the radius of curvature of the image side surface of the first positive lens, r2f is the radius of curvature of the object side surface of the second negative lens, f1 is the focal length of the first positive lens, and f2 is the focal point of the second negative lens. Distance. The imaging optical system according to claim 1 or 2, wherein the following condition (2) is satisfied.
(2) 0.1 <f1 / f <3.0
Here, f1 is the focal length of the first positive lens, and f is the focal length of the entire system. The imaging optical system according to claim 1, 2 or 3, wherein the following condition (3) is satisfied.
(3) 1.0 <f23 / f <4.0
Here, f23 is the combined focal length of the second lens and the third lens, and f is the focal length of the entire system. 5. The imaging optical system according to claim 1, wherein the imaging optical system satisfies the following condition (4).
(4) -10.0 <f1 / f23 <3.0
Here, f1 is the focal length of the first positive lens, and f23 is the combined focal length of the second negative lens and the third positive lens. The imaging optical system according to claim 1, 2, 3, 4, or 5, wherein the following condition (5) is satisfied.
(5) 0.1 <(ν2-ν1) / (ν3-ν2) <8.0
Here, ν1, ν2, and ν3 are Abbe numbers of the first lens, the second lens, and the third lens, respectively. An imaging optical system for forming an object image on an image sensor disposed on an imaging plane, wherein the following condition (7) is satisfied: 6 imaging optical system;
(7) 0.50 [μm] <Fno / P [μm] <2.00 [μm]
Here, Fno is the open F number of the imaging optical system, and P is the pixel interval of the image sensor. An optical apparatus comprising the imaging optical system according to claim 1, 2, 3, 4, 5, 6, or 7.