Folded camera lens designs
Digital cameras, optical lens modules for such digital cameras and methods for assembling lens elements in such lens modules. In various embodiments, the digital cameras comprise an optical lens module including N≥3 lens elements L i , each lens element comprising a respective front surface S 2i−1 and a respective rear surface S 2i . In various embodiments the first lens element toward the object side, L 1 and its respective front surfaces S 1 have optical and/or mechanical properties, such as a clear aperture, a clear height and a mechanical height that are larger than respective properties of following lens elements and surfaces. This is done to achieve a camera with large aperture stop, given a lens and/or camera height.
1. A digital camera comprising:
a) an optical lens module including N≥3 lens elements L i having a first optical axis, each lens element comprising a respective front surface S 2i−1 and a respective rear surface S 2i wherein 1≤i≤N, 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 wherein clear height value CH(S 1 ) of surface S 1 is greater than a clear height value of each of surfaces S 2 to S 2N ,
b) an image sensor; and
c) an optical path folding element (OPFE) for providing a folded optical path between an object and the lens elements.
2. The digital camera of claim 1 , wherein the N lens elements have an axial symmetry.
3. The digital camera of claim 1 , wherein CH(S 1 )≥1.1×CH(S 2 ).
4. The digital camera of claim 3 , wherein CH(S 1 )≥1.2× CH(S k ) for 3≤k≤2N.
5. The digital camera of claim 1 , wherein the digital camera has a total track length TTL and a focal back length BFL and wherein BFL≥0.3×TTL.
6. The digital camera of claim 1 , wherein L 1 is made of glass.
7. The digital camera of claim 1 , wherein L 1 is made of plastic.
8. The digital camera of claim 7 , wherein L i is made of plastic for any 2≤i≤N.
9. The digital camera of claim 1 , wherein the optical lens module is a front aperture lens.
10. The digital camera of claim 1 , wherein CH(S 1 )<7 mm.
11. The digital camera of claim 1 , wherein each respective lens element surface S k has a clear aperture value CA(S k ) and wherein CA(S 1 ) is greater than CA(S k ) for 2≤k≤2N−1, and wherein CA(S 2N )≤CA(S 1 ).
12. The digital camera of claim 11 , wherein CA(S 1 ) is substantially equal to CH(S 1 ).
13. The digital camera of claim 11 , wherein CA(S 1 )≥1.1×CA(S 2 ).
14. The digital camera of claim 11 , wherein CA(S 1 )≥1.2× CA(S k ) for 3≤k≤2N.
15. The digital camera of claim 1 , wherein at least some of the lens elements have a width W L greater than their height H L .
16. The digital camera of claim 11 , wherein CA(S 1 ) is substantially equal to CA(S 2N ).
17. The digital camera of claim 16 , wherein CA(S 1 ) is substantially equal to CH(S 1 ).
18. The digital camera of claim 1 , wherein the optical lens module includes a cavity that holds the plurality of lens elements, wherein the cavity comprises a first portion in which the first lens element Li is located and a second portion in which a least one of the other lens elements are located, wherein the height of the first portion is greater than the height of the second portion.
19. The digital camera of claim 1 , wherein the optical lens module includes a cavity that holds at least some of lens elements L 2 to L N , wherein first lens element L 1 is located outside of the optical lens module.
20. The digital camera of claim 1 , wherein the image sensor is a rectangular sensor or a circular sensor.
21. The digital camera of claim 1 , wherein N≤6.
22. A digital dual-camera, comprising:
a) the digital camera of claim 1 , wherein the camera is a Tele sub-camera configured to provide a Tele image; and
b) a Wide sub-camera configured to provide a Wide image.