US 12,072,552 B2
Wide-angle lens
Tsukasa Tsuchiya, Nagano (JP)
Assigned to NIDEC SANKYO CORPORATION, Nagano (JP)
Appl. No. 17/427,661
Filed by NIDEC SANKYO CORPORATION, Nagano (JP)
PCT Filed Jan. 9, 2020, PCT No. PCT/JP2020/000400
§ 371(c)(1), (2) Date Aug. 2, 2021,
PCT Pub. No. WO2020/162094, PCT Pub. Date Aug. 13, 2020.
Claims priority of application No. 2019-019787 (JP), filed on Feb. 6, 2019.
Prior Publication US 2022/0146797 A1, May 12, 2022
Int. Cl. G02B 9/60 (2006.01); G02B 13/06 (2006.01); G02B 13/18 (2006.01)
CPC G02B 9/60 (2013.01) [G02B 13/06 (2013.01); G02B 13/18 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A wide-angle lens comprising:
a plurality of lenses; and
a diaphragm,
wherein the plurality of lenses are a first lens, a second lens, a third lens, a fourth lens, and a fifth lens that are arranged in this order from an object side,
the diaphragm is arranged between the third lens and the fourth lens,
the first lens is a negative meniscus lens in which a lens surface on an image side is a concave curved surface,
the second lens is a biconcave lens in which both of a lens surface on the object side and a lens surface on the image side are concave curved surfaces,
the third lens is a biconvex lens in which both of a lens surface on the object side and a lens surface on the image side are convex curved surfaces,
the fourth lens is a negative lens in which a lens surface on the image side is a concave curved surface,
the fifth lens is a biconvex lens in which both of a lens surface on the object side and a lens surface on the image side are convex curved surfaces, and
when a refractive index of the first lens is set as n1, a focal length of the second lens is set as f2, and a focal length of an entire lens system is set as f0, the refractive index n1, the focal length f2, and the focal length f0 satisfy both of the following conditional expressions,
1.800<n1
−3.000<f2/f0<−2.500,
wherein
when a focal length of the first lens is set as f1, the focal length f1 and the focal length f0 satisfy the following conditional expression,
−5.000<f1/f0<−1.000.