CPC G02B 13/0045 (2013.01) [G02B 9/60 (2013.01)] | 17 Claims |
1. An optical imaging system, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens in sequence from an object side to an image side along an optical axis, wherein
the first lens has positive focal power, with an object-side surface being convex at the optical axis;
the second lens has focal power, with an image-side surface being concave convex at the optical axis;
the third lens has focal power;
the fourth lens has positive focal power, with an image-side surface being convex at the optical axis;
the fifth lens has negative focal power, with an object-side surface being convex at the optical axis and an image-side surface being concave at the optical axis, at least one of the object-side surface and the image-side surface of the fifth lens comprising at least one inflection point;
a diaphragm is arranged between the object side of the optical imaging system and the fifth lens; and
the optical imaging system satisfies the following relations:
SD11/SD12<1.1; and
80°≤FOV≤120°;
where SD11 is a maximum effective semi-diameter of the object-side surface of the first lens, SD12 is a maximum effective semi-diameter of an image-side surface of the first lens, and FOV is a maximum field-of-view angle of the optical imaging system,
|θ|<20°;
where θ is an angle between a tangent line of a vertex of a maximum effective diameter of the object-side surface of the first lens and a normal of the optical axis.
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