Optical imaging lens group
The present disclosure discloses an optical imaging lens group. The optical imaging lens group comprises, sequentially along an optical axis from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have refractive powers. At least one lens in the first lens to the eighth lens has a non-rotationally symmetric aspheric surface; a total effective focal length fy of the optical imaging lens group in a Y-axis direction and a total effective focal length fx of the optical imaging lens group in an X-axis direction satisfy: fy/fx<0.8; and an f-number Fnoy of the optical imaging lens group in the Y-axis direction satisfies: Fnoy<2.9.
1. An optical imaging lens group, comprising, sequentially along an optical axis from an object side to an image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have refractive powers,
wherein at least one lens in the first lens to the eighth lens has a non-rotationally symmetric aspheric surface;
the seventh lens has a positive refractive power, and an image-side surface of the seventh lens is a convex surface;
a total effective focal length fy of the optical imaging lens group in a Y-axis direction and a total effective focal length fx of the optical imaging lens group in an X-axis direction satisfy: fy/fx<0.8; and
an f-number Fnoy of the optical imaging lens group in the Y-axis direction satisfies: Fnoy<2.9.
2. The optical imaging lens group according to claim 1 , wherein an f-number Fnox of the optical imaging lens group in the X-axis direction satisfies: Fnox<3.0.
3. The optical imaging lens group according to claim 1 , wherein an effective focal length f1y of the first lens in the Y-axis direction of the optical imaging lens group, an effective focal length f8y of the eighth lens in the Y-axis direction of the optical imaging lens group and an effective focal length f8x of the eighth lens in the X-axis direction of the optical imaging lens group satisfy: 0.5<(f8x+f8y)/f1y<1.5.
4. The optical imaging lens group according to claim 1 , wherein an effective focal length f4 of the fourth lens in the Y-axis direction of the optical imaging lens group, an effective focal length f5 of the fifth lens in the Y-axis direction of the optical imaging lens group and an effective focal length f7 of the seventh lens in the Y-axis direction of the optical imaging lens group satisfy:−1.5<(f4+f7)/f5<−0.5.
5. The optical imaging lens group according to claim 1 , wherein an effective focal length f3y of the third lens in the Y-axis direction of the optical imaging lens group and an effective focal length f3x of the third lens in the X-axis direction of the optical imaging lens group satisfy: 0.5<f3y/(f3y+f3x)<2.0.
6. The optical imaging lens group according to claim 1 , wherein a radius of curvature R1 of an object-side surface of the first lens, a radius of curvature R2 of an image-side surface of the first lens, a radius of curvature R5 of an object-side surface of the third lens and a radius of curvature R6 of an image-side surface of the third lens satisfy: 0<(R5+R6)/(R1+R2)<1.0.
7. The optical imaging lens group according to claim 1 , wherein a radius of curvature R7 of an object-side surface of the fourth lens, a radius of curvature R8 of an image-side surface of the fourth lens, a radius of curvature R9 of an object-side surface of the fifth lens and a radius of curvature R10 of an image-side surface of the fifth lens satisfy: 0<(R9+R10)/(R7−R8)<1.0.
8. The optical imaging lens group according to claim 1 , wherein a radius of curvature R14 of an image-side surface of the seventh lens, a radius of curvature R15 of an object-side surface of the eighth lens and a radius of curvature R16 of an image-side surface of the eighth lens satisfy: 0.2<R14/(R16−R15)<1.0.
9. The optical imaging lens group according to claim 1 , wherein a maximal effective radius DT21 of an object-side surface of the second lens and a maximal effective radius DT81 of an object-side surface of the eighth lens satisfy: 0.5<DT21/DT81<1.0.
10. The optical imaging lens group according to claim 1 , wherein an edge thickness ET5 of the fifth lens and an edge thickness ET6 of the sixth lens satisfy: 0.3<ET6/ET5<0.8.
11. The optical imaging lens group according to claim 1 , wherein a maximal effective radius DT32 of an image-side surface of the third lens and a maximal effective radius DT52 of an image-side surface of the fifth lens satisfy: 0.5<DT52/DT32<1.0.
12. The optical imaging lens group according to claim 1 , wherein a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis and a center thickness CT5 of the fifth lens on the optical axis satisfy: 1.3<(CT2+CT3)/(CT4+CT5)<2.0.
13. The optical imaging lens group according to claim 1 , wherein a center thickness CT6 of the sixth lens on the optical axis, a center thickness CT7 of the seventh lens on the optical axis and a center thickness CT8 of the eighth lens on the optical axis satisfy: 0.3<CT7/(CT6−CT8)<0.8.
14. The optical imaging lens group according to claim 1 , wherein the fifth lens has a negative refractive power.
15. The optical imaging lens group according to claim 1 , wherein the eighth lens has a negative refractive power, an object-side surface of the eighth lens is a concave surface, and an image-side surface of the eighth lens is a convex surface at an area close to the optical axis in the Y-axis direction of the optical imaging lens group.
16. The optical imaging lens group according to claim 1 , wherein a maximal field-of-view FOV of the optical imaging lens group in a direction of a bisector of an angle between the Y-axis direction and the X-axis direction satisfies: FOV>80°.
17. The optical imaging lens group according to claim 1 , wherein the f-number Fnoy of the optical imaging lens group in the Y-axis direction and an f-number Fnox of the optical imaging lens group in the X-axis direction satisfy: Fnox/Fnoy≥1.1.
18. An optical imaging lens group, comprising, sequentially along an optical axis from an object side to an image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens have refractive powers,
wherein at least one lens in the first lens to the eighth lens has a non-rotationally symmetric aspheric surface;
an effective focal length f3y of the third lens in a Y-axis direction of the optical imaging lens group and an effective focal length f3x of the third lens in an X-axis direction of the optical imaging lens group satisfy: 0.5<f3y/(f3y+f3x)<2.0; and
an f-number Fnoy of the optical imaging lens group in the Y-axis direction satisfies: Fnoy<2.9.
19. The optical imaging lens group according to claim 18 , wherein an f-number Fnox of the optical imaging lens group in the X-axis direction satisfies: Fnox<3.0.