Slim pop-out tele camera lenses
Lens systems for compact digital cameras having a pop-out state and a collapsed state, the lens systems comprising: an image sensor having a sensor diagonal SD, and a lens with N≥6 lens elements L1-LN arranged along a lens optical axis (OA) starting with L1 from an object side toward an image side, each lens element Li having a respective clear aperture diameter DA Li 1≤i≤N, and having in the pop-out state a field of view 35deg<FOV<50deg, a f number (f/ #), a lens thickness T Lens , a back focal length BFL, an effective focal length EFL, and a total track length TTL<20 mm, the lens having in the collapsed state a collapsed total track length c-TTL, wherein c-TTL=T Lens +1 mm, wherein EFL≥10 mm, wherein f/ #<2, and wherein a ratio c-TTL/EFL<0.8.
1 . A lens system for a compact digital camera, the lens system configured to switch from a pop-out state associated with a total track length (TTL) to a collapsed state associated with a collapsed total track length (c-TTL) that fulfills c-TTL<TTL and vice versa by collapsing a back focal length BFL to a collapsed BFL (c-BFL)<BFL and vice versa, the lens system comprising:
an image sensor; and
a lens with N≥6 lens elements L1-LN arranged from an object side towards an image side along a lens optical axis (OA) starting with a first lens element L1 and having an effective focal length (EFL), the first lens element L1 having a clear aperture diameter DA L1 ≥7 mm,
wherein the lens has a 35 mm equivalent focal length (35 mm EqFL) in the range of 30 mm<35 mm EqFL<100 mm and a f number (f/ #)≤2, wherein TTL<15 mm, and wherein 0.9×EFL<TTL<1.1×EFL.
2 . The lens system of claim 1 , wherein c-TTL/EFL<0.8.
3 . The lens system of claim 1 , wherein c-TTL/EFL<0.7.
4 . The lens system of claim 1 , wherein the lens has a lens thickness T Lens measured along the OA, and wherein c-TTL≤T Lens +1 mm.
5 . The lens system of claim 4 , wherein c-TTL≤T Lens +0.7 mm.
6 . The lens system of claim 1 , wherein N≥7, and wherein TTL<14 mm.
7 . The lens system of claim 6 , wherein TTL≤13 mm.
8 . The lens system of claim 1 , wherein f/ #<1.9.
9 . The lens system of claim 1 , wherein f/ #<1.7.
10 . The lens system of claim 1 , wherein 0.04≤c-BFL/BFL<0.9.
11 . The lens system of claim 1 , wherein 35 mm<35 mm EqFL<70 mm.
12 . The lens system of claim 1 , wherein 40 mm<35 mm EqFL<55 mm.
13 . The lens system of claim 1 , wherein lens elements L1, L2, L3 and L4 have respective air gaps therebetween with respective widths d12, d23 and d34 along the OA, and wherein each of d12, d23 and d34 is smaller than 0.5 mm.
14 . The lens system of claim 1 , wherein lens elements L1, L2, L3 and L4 have respective air gaps therebetween with respective widths d12, d23 and d34 along the OA, and wherein respective ratios between each of d12, d23 and d34 and the TTL, d12/TTL, d23/TTL and d34/TTL, are smaller than 5%.
15 . The lens system of claim 1 , wherein L1 and L2 have respective thicknesses T1 and T2 along the OA greater than 1 mm, have respective refractive indices n1 and n2 smaller than 1.55, have respective Abbe numbers v1 and v2 greater than 50, and each have a positive lens power.
16 . The lens system of claim 1 , wherein L1 and L2 form a doublet lens.
17 . The lens system of claim 1 , wherein L2 and L3 form a doublet lens.
18 . The lens system of claim 1 , wherein L4 and L5 form a doublet lens.
19 . The lens system of claim 1 , wherein L6 and L7 form a doublet lens.
20 . The lens system of claim 1 , wherein the lens system is integrated in a camera module, and wherein the camera module is integrated in a smartphone.