Folded camera lens designs including eight lenses of +−+−+++− refractive powers
Folded cameras with a total track length (TTL), f numbers smaller than 1.2 and large fields of view, e.g. of at least 60 degrees. Such folded cameras may comprise a lens with N≥7 lens elements, an image sensor and an optical path folding element for providing a folded optical path between an object and the lens, wherein an aperture stop of the lens is located closer to a first surface of the first lens element facing the object than a distance d that fulfills d/TTL=0.2.
1. A folded camera, comprising:
a) a lens having an effective focal length (EFL) and including N≥7 lens elements L i along a lens optical axis, wherein a first lens element L 1 faces an object side, each lens element L i comprising a respective front surface S 2i-1 and a respective rear surface S 2i , the lens element surfaces marked S k where 1≤k≤2N, wherein each lens element surface S k has a clear height value CH(S k ) and a clear aperture value CA(S k );
b) a lens barrel carrying the lens;
c) an image sensor; and
d) an optical path folding element (OPFE) for folding a first optical path parallel to a plane that includes the image sensor to a second optical path perpendicular to the first optical path and parallel to the lens optical axis,
wherein the folded camera has a total track length (TTL), wherein an aperture stop of the lens is located closer to a first surface of the first lens element facing the object than a distance d that fulfills d/TTL=0.2, and wherein the camera has an f number f/#<1.1, and
wherein a clear aperture value CA(S 2N ) in the lens element L N is greater than a clear aperture value CA(S 1 ) in the lens element L 1 .
2. The folded camera of claim 1 , wherein f/#≤1.0.
3. The folded camera of claim 1 , additionally including an optical element located between the lens and the image sensor.
4. The folded camera of claim 1 , wherein the camera has a diagonal field of view (FOV) larger than 60 degrees.
5. The folded camera of claim 1 , wherein at least some of the lens elements are cut lens elements that have a width W Li greater than a height H Li , wherein H Li is measured along a direction parallel to the first optical path, and wherein W L,i is measured along a direction perpendicular to the first optical path and perpendicular to the second optical path.
6. The folded camera of claim 1 , wherein at least some of the lens elements have a width W Li and a height H Li that satisfy W Li /H Li >1.1.
7. The folded camera of claim 1 , wherein at least some of the lens elements have a width W Li and a height H Li that satisfy W Li /H Li >1.2.
8. The folded camera of claim 1 , wherein the lens barrel has a lens barrel height≤5.5 mm.
9. The folded camera of claim 1 , wherein the image sensor has a sensor diagonal SD>6 mm.
10. The folded camera of claim 1 , wherein for the OPFE has a height H O , wherein the lens has a height H L and wherein H O >H L , wherein H O and H L are measured along a direction parallel to the first optical path.
11. The folded camera of claim 1 , wherein for an OPFE's height H O and a lens barrel height H LB , H O >H LB , wherein H O and H LB are measured along a direction parallel to the first optical path.
12. The folded camera of claim 1 , wherein the camera has a height He determined by a height H O of the OPFE, and wherein H O and He are measured along a direction parallel to the first optical path.
13. The folded camera of claim 1 , wherein |f i |>5×EFL for 1≤i≤3.
14. The folded camera of claim 1 , wherein lens element L 5 has a strongest optical power of all lens elements |f 5 |<|f i | for i±5.
15. The folded camera of claim 1 , wherein f 5 <EFL.
16. The folded camera of claim 1 , wherein a lens sub-system that includes lens elements L 4 and L 5 has positive refractive power.
17. The folded camera of claim 1 , wherein focal lengths f 4 of L 4 and f 5 of L 5 satisfy |f 4 |<4×f 5 .
18. The folded camera of claim 1 , wherein focal lengths f 4 of L 4 and f 5 of L 5 satisfy |f 4 |<3×f 5 .
19. The folded camera of claim 1 , wherein the lens includes at least one air gap between lens elements that complies with the condition STD <0.020, where STD is a normalized gap standard deviation.
20. The folded camera of claim 1 , wherein an air gap between lens elements L 4 and L 5 satisfies STD <0.020, where STD is a normalized gap standard deviation.
21. A folded camera comprising:
a) a lens having an effective focal length (EFL) and including N≥7 lens elements L i along a lens optical axis, wherein a first lens element L 1 faces an object side, each lens element L i having a respective focal length f i , and comprising a respective front surface S 2i-1 and a respective rear surface S 2i , the lens element surfaces marked S k where 1≤k≤2N, wherein each lens element surface S k has a clear height value CH(S k ) and a clear aperture CA(S k ), wherein clear height value CH(S 2N ) of the last surface S 2N is greater than or equal to a clear height value of each of surfaces S 2 to S 2N−1 ;
b) a lens barrel carrying the lens;
c) an image sensor; and
d) an optical path folding element (OPFE) for folding a first optical path parallel to a plane that includes the image sensor to a second optical path perpendicular to the first optical path and parallel to the lens optical axis,
wherein the folded camera has a total track length (TTL), wherein an aperture stop of the lens is located closer to a first surface of the first lens element facing the object than a distance d that fulfills d/TTL=0.2, and wherein the camera has an f number f/#<1.1, and
wherein a clear aperture value CA(S 2N ) in the lens element L N is greater than a clear aperture value CA(S 1 ) in the lens element L 1 .
22. The folded camera of claim 21 , wherein f/#≤1.0.
23. The folded camera of claim 21 , wherein the camera has a diagonal field of view (FOV) that is larger than 60 degrees.
24. The folded camera of claim 21 , wherein |f i |>4×EFL for 1≤i≤3.
25. The folded camera of claim 21 , wherein |f i |>5×EFL for 1≤i≤3.
26. The folded camera of claim 21 , wherein lens element L 5 has a strongest optical power of all lens elements |f 5 |≤|f i | for i±5.
27. The folded camera of claim 21 , wherein f 5 <EFL.
28. The folded camera of claim 21 , wherein a lens sub-system that includes lens elements L 4 and L 5 has positive refractive power.
29. The folded camera of claim 21 , wherein focal lengths f 4 of L 4 and f 5 of L 5 satisfy |f 4 |<4×f 5 .
30. The folded camera of claim 21 , wherein focal lengths f 4 of L 4 and f 5 of L 5 satisfy |f 4 |<3×f 5 .
31. The folded camera of claim 21 , wherein the lens includes at least one air gap between lens elements that comply with the condition STD <0.020, where STD is a normalized gap standard deviation.
32. The folded camera of claim 21 , wherein the lens includes at least one air gap between lens elements that comply with the condition STD <0.010, where STD is a normalized gap standard deviation.
33. The folded camera of claim 21 , wherein an air gap between lens elements L 4 and L 5 satisfies STD <0.020, where STD is a normalized gap standard deviation.
34. The folded camera of claim 21 , additionally including an optical element, wherein the optical element is located between the lens and the image sensor.
35. The folded camera of claim 1 wherein the at least one lens elements L i having a clear aperture value CA(S k ) greater than the clear height value CH(S k ) comprises all the lens elements L i .