US 12,270,974 B1
Image forming lens
Makoto Uehara, Tokyo (JP); and Kouhei Nakamura, Tokyo (JP)
Assigned to MEJIRO 67 INC., Tokyo (JP)
Appl. No. 18/839,730
Filed by MEJIRO 67 INC., Tokyo (JP)
PCT Filed May 18, 2023, PCT No. PCT/JP2023/018580
§ 371(c)(1), (2) Date Aug. 20, 2024,
PCT Pub. No. WO2023/234051, PCT Pub. Date Dec. 7, 2023.
Claims priority of application No. 2022-089667 (JP), filed on Jun. 1, 2022.
Int. Cl. G02B 13/00 (2006.01); H04N 23/55 (2023.01)
CPC G02B 13/0045 (2013.01) [G02B 13/006 (2013.01); H04N 23/55 (2023.01)] 20 Claims
OG exemplary drawing
 
1. An imaging lens, comprising:
a focusing lens assembly with a positive refractive power, enabled to move in a direction of an optical axis depending on an object distance; and
a fixed lens assembly with a negative refractive power, fixedly disposed in a vicinity of an imaging plane,
wherein the focusing lens assembly comprises two positive lens groups with an aperture disposed therebetween;
the focusing lens assembly comprises, sequentially from the object side, a 2-division-3-piece front group with a positive refractive power consisting of a single lens and doublet lenses, the aperture, and a 2-division-3-piece back group with a positive refractive power consisting of doublet lenses and a single lens; and
one of the lens of the focusing lens assembly, which is closest to the object side, is a meniscus lens that is convex at the object side and concave at an image side, and has a weakest refractive power out of all, and the front group and the back group, between which the aperture is disposed, have respective focal lengths f1 and f2 complying with a correlation of 0.9<f1/f2<1.3.