Camera optical lens including six lenses of ++-+-+ refractive powers

1. A camera optical lens comprising, from an object side to an image side:

a first lens;

a second lens having a positive refractive power;

a third lens having a negative refractive power;

a fourth lens;

a fifth lens; and

a sixth lens;

wherein at least one of the lenses has an off-axis critical point on object side surface and/or image side surface, and the camera optical lens satisfies following conditions:

1.00≤ f 1/ f 2≤3.00; and

4.00≤( R 1+ R 2)/( R 1− R 2)≤15.00;

where

f1 denotes a focal length of the first lens;

f2 denotes a focal length of the second lens;

R1 denotes a curvature radius of an object-side surface of the first lens; and

R2 denotes a curvature radius of an image-side surface of the first lens.

2. The camera optical lens according to claim 1 further satisfying following conditions:

1.2≤ f 1/ f 2≤3.00; and

4.08≤( R 1+ R 2)/( R 1− R 2)≤14.95.

3. The camera optical lens according to claim 1 , wherein the first lens has a positive refractive power, the object-side surface of the first lens is concave in a paraxial region and the image-side surface of the first lens is convex in the paraxial region; and

the camera optical lens further satisfies following conditions:

1.22≤ f 1/ f≤ 7.78; and

0.03≤ d 1/ TTL≤ 0.09;

where

f denotes a focal length of the camera optical lens;

d1 denotes an on-axis thickness of the first lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

4. The camera optical lens according to claim 3 further satisfying following conditions:

1.96≤ f 1/ f≤ 6.23; and

0.04≤ d 1/ TTL≤ 0.07.

5. The camera optical lens according to claim 1 , wherein the second lens comprises an object-side surface being convex in a paraxial region and an image-side surface being concave in the paraxial region; and

the camera optical lens further satisfies following conditions:

0.87≤ f 2/ f≤ 3.53;

−5.65≤( R 3+ R 4)/( R 3− R 4)≤−1.58; and

0.06≤ d 3/ TTL≤ 0.18;

where

f denotes a focal length of the camera optical lens;

R3 denotes a curvature radius of the object-side surface of the second lens;

R4 denotes a curvature radius of the image-side surface of the second lens;

d3 denotes an on-axis thickness of the second lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

6. The camera optical lens according to claim 5 further satisfying following conditions:

1.39≤ f 2/ f≤ 2.83;

−3.53≤( R 3+ R 4)/( R 3− R 4)≤−1.98; and

0.09≤ d 3/ TTL≤ 0.15.

7. The camera optical lens according to claim 1 , wherein the third lens comprises an object-side surface being convex in a paraxial region and an image-side surface being concave in the paraxial region, and

the camera optical lens further satisfies following conditions:

−32.92≤ f 3/ f≤− 5.46;

2.00≤( R 5+ R 6)/( R 5− R 6)≤10.76; and

0.03≤ d 5/ TTL≤ 0.10;

where

f denotes a focal length of the camera optical lens;

f3 denotes a focal length of the third lens;

R5 denotes a curvature radius of the object-side surface of the third lens;

R6 denotes a curvature radius of the image-side surface of the third lens;

d5 denotes an on-axis thickness of the third lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

8. The camera optical lens according to claim 7 further satisfying following conditions:

−20.57≤ f 3/ f≤− 6.82;

3.20≤( R 5+ R 6)/( R 5− R 6)≤8.61; and

0.05≤ d 5/ TTL≤ 0.08.

9. The camera optical lens according to claim 1 , wherein the fourth lens has a positive refractive power, and comprises an object-side surface being concave in a paraxial region and an image-side surface being convex in the paraxial region, and

the camera optical lens further satisfies following conditions:

0.83≤ f 4/ f≤ 2.55;

0.99≤( R 7+ R 8)/( R 7− R 8)≤3.04; and

0.04≤ d 7/ TTL≤ 0.13;

where

f denotes a focal length of the camera optical lens;

f4 denotes a focal length of the fourth lens;

R7 denotes a curvature radius of the object-side surface of the fourth lens;

R8 denotes a curvature radius of the image-side surface of the fourth lens;

d7 denotes an on-axis thickness of the fourth lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

10. The camera optical lens according to claim 9 further satisfying following conditions:

1.33≤ f 4/ f≤ 2.04;

1.59≤( R 7+ R 8)/( R 7− R 8)≤2.43; and

0.06≤ d 7/ TTL≤ 0.10.

11. The camera optical lens according to claim 1 , wherein the fifth lens has a negative refractive power, and comprises an object-side surface being concave in a paraxial region and an image-side surface being convex in the paraxial region, and

the camera optical lens further satisfies following conditions:

−2.34≤ f 5/ f≤− 0.77;

−8.61≤( R 9+ R 10)/( R 9− R 10)≤−2.75; and

0.03≤ d 9/ TTL≤ 0.10;

where

f denotes a focal length of the camera optical lens;

f5 denotes a focal length of the fifth lens;

R9 denotes a curvature radius of the object-side surface of the fifth lens;

R10 denotes a curvature radius of the image-side surface of the fifth lens;

d9 denotes an on-axis thickness of the fifth lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

12. The camera optical lens according to claim 11 further satisfying following conditions:

−1.47≤ f 5/ f≤− 0.96;

−5.38≤( R 9+ R 10)/( R 9− R 10)≤−3.44; and

0.05≤ d 9/ TTL≤ 0.08.

13. The camera optical lens according to claim 1 , wherein the sixth lens has a positive refractive power, and comprises an object-side surface being convex in a paraxial region and an image-side surface being concave in the paraxial region, and

the camera optical lens further satisfies following conditions:

0.88≤ f 6/ f≤ 2.65;

−42.79≤( R 11+ R 12)/( R 11− R 12)≤−13.66; and

0.08≤ d 11/ TTL≤ 0.24;

where

f denotes a focal length of the camera optical lens;

f6 denotes a focal length of the sixth lens;

R11 denotes a curvature radius of the object-side surface of the sixth lens;

R12 denotes a curvature radius of the image-side surface of the sixth lens;

d11 denotes an on-axis thickness of the sixth lens; and

TTL denotes a total optical length from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis.

14. The camera optical lens according to claim 13 further satisfying following conditions:

1.40≤ f 6/ f≤ 2.12;

−26.74≤( R 11+ R 12)/( R 11− R 12)≤−17.08; and

0.12≤ d 11/ TTL≤ 0.19.

15. The camera optical lens according to claim 1 further satisfying following condition:

0.58≤ f 12/ f≤ 1.89;

where

f denotes a focal length of the camera optical lens;

f12 denotes a combined focal length of the first lens and the second lens.

16. The camera optical lens according to claim 15 further satisfying following condition:

0.93≤ f 12/ f≤ 1.52.

17. The camera optical lens according to claim 1 , where a total optical length TTL from the object-side surface of the first lens to an image surface of the camera optical lens along an optical axis is less than or equal to 5.06 mm.

18. The camera optical lens according to claim 17 , wherein the total optical length TTL of the camera optical lens is less than or equal to 4.83 mm.

19. The camera optical lens according to claim 1 , wherein an F number of the camera optical lens is less than or equal to 2.27.

20. The camera optical lens according to claim 19 , wherein the F number of the camera optical lens is less than or equal to 2.22.