US 12,235,518 B2
Lens assembly
Tsan-Haw Lee, Taichung (TW); and Rong-Shun Syu, Taichung (TW)
Assigned to SINTAI OPTICAL (SHENZHEN) CO., LTD., Shenzhen (CN); and ASIA OPTICAL CO., INC., Taichung (TW)
Filed by Sintai Optical (Shenzhen) Co., Ltd., Guandong (CN); and Asia Optical Co., Inc., Taichung (TW)
Filed on Dec. 7, 2021, as Appl. No. 17/543,868.
Claims priority of application No. 202011481740.3 (CN), filed on Dec. 16, 2020; and application No. 202011516284.1 (CN), filed on Dec. 21, 2020.
Prior Publication US 2022/0187569 A1, Jun. 16, 2022
Int. Cl. G02B 9/64 (2006.01)
CPC G02B 9/64 (2013.01) 16 Claims
OG exemplary drawing
 
1. A lens assembly comprising:
a first lens which is a meniscus lens with refractive power;
a second lens which is with refractive power and comprises a concave surface facing an image side;
a third lens which is with negative refractive power and comprises a concave surface facing an object side;
a fourth lens which is with positive refractive power;
a fifth lens which is with positive refractive power and comprises a convex surface facing the object side;
a sixth lens which is with positive refractive power and comprises a convex surface facing the image side;
a seventh lens which is with refractive power;
an eighth lens which is with refractive power and comprises a convex surface facing the image side; and
a ninth lens which is with positive refractive power and comprises a convex surface facing the object side;
wherein the refractive power of the first lens and the refractive power of the second lens are opposite in sign;
wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are arranged in order from the object side to the image side along an optical axis;
wherein the lens assembly satisfies at least one of following conditions:
Vd4>35;
10 mm<f4−Rk2<56.5 mm;
wherein Vd4 is an Abbe number of the fourth lens, f4 is an effective focal length of the fourth lens, Rk2 is a radius of curvature of an image side surface of the lens second close to the image side;
wherein the lens assembly satisfies following conditions:
−22<(Rm2+f1)/fk<−1;
wherein f1 is an effective focal length of the first lens, fk is an effective focal length of the lens second close to the image side, and Rm2 is a radius of curvature of an image side surface of the lens closest to the image side;
wherein an air gap is disposed between the sixth lens and the seventh lens;
wherein the lens assembly further satisfies:
3.0≤TTL/f≤3.8;
wherein f is an effective focal length of the lens assembly and TTL is an interval from an object side surface of the first lens to an image plane along the optical axis.