Image capturing optical system, imaging apparatus and electronic device
An image capturing optical system includes seven lens elements, the seven lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. An image-side surface of the fifth lens element is convex in a paraxial region thereof. An image-side surface of the sixth lens element is concave in a paraxial region thereof. The seventh lens element has negative refractive power.
1. An image capturing optical system comprising seven lens elements, the seven lens elements being, in order from an object side to an image side:
a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element;
wherein each of the seven lens elements has an object-side surface towards the object side and an image-side surface towards the image side;
wherein an image-side surface of the fifth lens element is convex in a paraxial region thereof; an image-side surface of the sixth lens element is concave in a paraxial region thereof; the seventh lens element has negative refractive power; an object-side surface of the seventh lens element is convex in a paraxial region thereof;
wherein each of at least three of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element has at least one surface being aspheric, and at least one surface of at least one of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element comprises at least one inflection point;
wherein an axial distance between the first lens element and the second lens element is smaller than an axial distance between the second lens element and the third lens element;
wherein an axial distance between an object-side surface of the first lens element and an image surface is TL, an entrance pupil diameter of the image capturing optical system is EPD, a focal length of the first lens element is f1, a focal length of the third lens element is f3, a curvature radius of an object-side surface of the third lens element is R5, a curvature radius of an image-side surface of the third lens element is R6, a curvature radius of the object-side surface of the seventh lens element is R13, a curvature radius of an image-side surface of the seventh lens element is R14, and the following conditions are satisfied:
1.05< TL/EPD< 2.38;
−1.50< f 3/ f 1<1.55;
−0.70< R 14/ R 13<1.40; and
| R 5/ R 6|<4.50.
2. The image capturing optical system of claim 1 , wherein the second lens element has negative refractive power.
3. The image capturing optical system of claim 1 , wherein the image-side surface of the seventh lens element is concave in a paraxial region thereof and comprises at least one convex shape in an off-axial region thereof.
4. The image capturing optical system of claim 1 , wherein a focal length of the image capturing optical system is f, the entrance pupil diameter of the image capturing optical system is EPD, and the following condition is satisfied:
0.85< f/EPD< 1.55.
5. The image capturing optical system of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, the entrance pupil diameter of the image capturing optical system is EPD, and the following condition is satisfied:
1.10< TL/EPD< 2.20.
6. The image capturing optical system of claim 5 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, the entrance pupil diameter of the image capturing optical system is EPD, and the following condition is satisfied:
1.15< TL/EPD< 2.0.
7. The image capturing optical system of claim 1 , wherein a curvature radius of the object-side surface of the first lens element is R1, the curvature radius of the image-side surface of the third lens element is R6, and the following condition is satisfied:
R 1/ R 6<0.25.
8. The image capturing optical system of claim 1 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, a focal length of the image capturing optical system is f, the entrance pupil diameter of the image capturing optical system is EPD, a maximum image height of the image capturing optical system is ImgH, and the following condition is satisfied:
( TL×f )/( EPD ×Img H )<2.50.
9. The image capturing optical system of claim 1 , wherein each of at least two of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element has an Abbe number smaller than 25.0, a focal length of the image capturing optical system is f, a focal length of the second lens element is f2, and the following condition is satisfied:
0.40<| f/f 2|<1.20.
10. The image capturing optical system of claim 1 , wherein a maximum of chief ray angles of the image capturing optical system is CRAmax, and the following condition is satisfied:
35.0 degrees<CRAmax<50.0 degrees.
11. The image capturing optical system of claim 1 , wherein a vertical distance between a non-axial critical point on the image-side surface of the sixth lens element and an optical axis is Yc62, a vertical distance between a non-axial critical point on the image-side surface of the seventh lens element and the optical axis is Yc72, and the following condition is satisfied:
0.50< Yc 72/ Yc 62<1.85.
12. The image capturing optical system of claim 1 , wherein a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of an image-side surface of the second lens element is R4, and the following condition is satisfied:
−1.50< R 4/ R 1<3.0.
13. The image capturing optical system of claim 1 , wherein a curvature radius of an object-side surface of the second lens element is R3, an axial distance between the object-side surface of the first lens element and the image-side surface of the seventh lens element is TD, and the following condition is satisfied:
−0.70< R 3/ TD< 0.80.
14. The image capturing optical system of claim 1 , wherein the axial distance between the first lens element and the second lens element is T12, the axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, an axial distance between the fifth lens element and the sixth lens element is T56, an axial distance between the sixth lens element and the seventh lens element is T67, and the following condition is satisfied:
7.50<( T 23+ T 34+ T 45+ T 67)/( T 12+ T 56)<45.0.
15. An imaging apparatus, comprising:
the image capturing optical system of claim 1 ;
a driving apparatus connected to the image capturing optical system; and
an image sensor, wherein the image sensor is disposed on an image surface of the image capturing optical system.
16. An electronic device, comprising:
the imaging apparatus of claim 15 .
17. An image capturing optical system comprising seven lens elements, the seven lens elements being, in order from an object side to an image side:
a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element;
wherein each of the seven lens elements has an object-side surface towards the object side and an image-side surface towards the image side;
wherein the second lens element has negative refractive power; the fifth lens element has positive refractive power; an image-side surface of the sixth lens element is concave in a paraxial region thereof; the seventh lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof;
wherein each of at least three of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element has at least one surface being aspheric, and at least one surface of at least one of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element comprises at least one inflection point;
wherein an axial distance between an object-side surface of the first lens element and an image surface is TL, a curvature radius of the image-side surface of the seventh lens element is R14, an entrance pupil diameter of the image capturing optical system is EPD, a focal length of the first lens element is f1, a focal length of the third lens element is f3, and the following conditions are satisfied:
1.05< TL/EPD< 2.38;
0.10< R 14/ EPD< 1.0; and
−7.0< f 3/ f 1<1.55.
18. The image capturing optical system of claim 17 , wherein the third lens element has positive refractive power.
19. The image capturing optical system of claim 17 , wherein one surface of the first lens element is concave in a paraxial region thereof, and the other surface of the first lens element is convex in a paraxial region thereof.
20. The image capturing optical system of claim 17 , further comprising:
an aperture stop located on an object side of the second lens element, wherein an axial distance between the aperture stop and the image-side surface of the seventh lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the seventh lens element is TD, and the following condition is satisfied:
0.80< SD/TD< 0.98.
21. The image capturing optical system of claim 17 , wherein a focal length of the image capturing optical system is f, the entrance pupil diameter of the image capturing optical system is EPD, and the following condition is satisfied:
0.75< f/EPD< 1.65.
22. The image capturing optical system of claim 17 , wherein the curvature radius of the image-side surface of the seventh lens element is R14, the entrance pupil diameter of the image capturing optical system is EPD, and the following condition is satisfied:
0.10< R 14/ EPD≤ 0.86.
23. The image capturing optical system of claim 17 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, a focal length of the image capturing optical system is f, the entrance pupil diameter of the image capturing optical system is EPD, a maximum image height of the image capturing optical system is ImgH, and the following condition is satisfied:
( TL×f )/( EPD ×Img H )<2.50.
24. The image capturing optical system of claim 17 , wherein each of at least two of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element has an Abbe number smaller than 25.0.
25. The image capturing optical system of claim 17 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, and the following condition is satisfied:
TL<7.5 mm.
26. The image capturing optical system of claim 17 , wherein a vertical distance between a non-axial critical point on the image-side surface of the seventh lens element and the optical axis is Yc72, a focal length of the image capturing optical system is f, and the following condition is satisfied:
0.10< Yc 72/ f< 0.85.
27. The image capturing optical system of claim 17 , wherein the focal length of the first lens element is f1, a focal length of the fourth lens element is f4, and the following condition is satisfied:
−0.30< f 1/ f 4<0.30.
28. The image capturing optical system of claim 17 , wherein the axial distance between the second lens element and the third lens element is T23, a central thickness of the second lens element is CT2, and the following condition is satisfied:
0.40< T 23/ CT 2<1.60.
29. The image capturing optical system of claim 17 , wherein an axial distance between the sixth lens element and the seventh lens element is T67, a central thickness of the sixth lens element is CT6, and the following condition is satisfied:
0.70< T 67/ CT 6<5.50.
30. The image capturing optical system of claim 17 , wherein the axial distance between the object-side surface of the first lens element and the image surface is TL, a maximum image height of the image capturing optical system is ImgH, a half of a maximum field of view of the image capturing optical system is HFOV, and the following conditions are satisfied:
TL /Img H <2.0; and
0.70<tan(HFOV)<1.20.