US 12,231,758 B2
Imaging optical system, and imaging device and camera system provided with same
Yoshiaki Kurioka, Osaka (JP); and Takahiro Kitada, Osaka (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
Filed on Jan. 10, 2023, as Appl. No. 18/095,240.
Application 18/095,240 is a continuation of application No. 16/437,372, filed on Jun. 11, 2019, granted, now 11,582,370.
Application 16/437,372 is a continuation of application No. PCT/JP2017/045241, filed on Dec. 18, 2017.
Claims priority of application No. 2016-254962 (JP), filed on Dec. 28, 2016.
Prior Publication US 2023/0171477 A1, Jun. 1, 2023
Int. Cl. G02B 15/20 (2006.01); G02B 7/02 (2021.01); G02B 13/18 (2006.01); G03B 17/14 (2021.01); H04N 23/55 (2023.01)
CPC H04N 23/55 (2023.01) [G02B 7/021 (2013.01); G02B 13/18 (2013.01); G02B 15/20 (2013.01); G03B 17/14 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An imaging optical system, comprising:
a lens group Gm having negative power and including
a lens element LGmF1 having a strongest negative power among lens elements located on an object side with respect to an aperture diaphragm, and
a lens element LGmF2 adjacent to an image side of the lens element LGmF1 and having a negative power, both surfaces of the lens element LGmF2 each having an aspherical shape;
a lens group Gf located on the image side of the lens group Gm, moving in an optical axis direction during focusing from an infinity focusing state to a proximity focusing state and having power; and
a lens element located on the image side of the lens group Gf,
wherein THGm_A is an air distance between the lens element LGmF1, which is a first lens element from the object side of the lens group Gm, and the lens element LGmF2, which is a second lens element from the object side of the lens group Gm, and THGm_B is an air distance between a lens element LGmR2, which is a second lens element from the image side of the lens group Gm, and a lens element LGmR3, which is a third lens element from the image side of the lens group Gm, and a condition (2) below is satisfied
0.5<THGm_A/THGm_B<1.5 . . .   (2),
wherein a lens element of the lens group Gm which is farthest on the image side is adjacent to the object side of the aperture diaphragm, and
wherein R2_LGmF1 is a radius of curvature on the image side of the lens element LGmF1, and R1_LGmF2 is a radius of curvature on the object side of the lens element LGmF2, and a condition (14) below is satisfied
1<(R1_LGmF2+R2_LGmF1)/(R1_LGmF2−R2_LGmF1)<1.6 . . .   (14).