Lens assembly

Patent metadata

Field	Value
Publication number	US-2016282585-A1
Application number	US-201514664941-A
Country	US
Kind code	A1
Filing date	Mar 23, 2015
Priority date	Mar 24, 2014
Publication date	Sep 29, 2016
Grant date	—

Abstract

A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is with negative refractive power. The second, third, fourth and sixth lens are with refractive power. The fifth lens is with positive refractive power. The lens assembly satisfies: 0.078≦BFL/TTL≦0.4, 0.01≦f/TTL≦0.61, (Nd 1 +Nd 2 +Nd 3 +Nd 4 +Nd 5 +Nd 6 )/6<(Nd 2 +Nd 3 )/2 wherein BFL is a distance from an image side surface of the sixth lens to an image plane along the optical axis, TTL is a distance from the convex surface of the first lens to the image plane along the optical axis, f is an effective focal length of the lens assembly, and Nd 1 , Nd 2 , Nd 3 , Nd 4 , Nd 5 and Nd 6 are indexes of refraction of the first, second, third, fourth, fifth and sixth lenses.

First claim

What is claimed is:

1 . A lens assembly comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in sequence from an object side to an image side along an optical axis, wherein:
the first lens is with negative refractive power and comprises a convex surface facing the object side and a concave surface facing the image side; the second lens is with refractive power; the third lens is with refractive power; the fourth lens is with refractive power; the fifth lens is with positive refractive power and comprises a convex surface facing the image side; the sixth lens is with refractive power; and the lens assembly satisfies:
0.078≦ BFL/TTL≦ 0.4,

0.01≦ f/TTL≦ 0.61,

( Nd 1 +Nd 2 +Nd 3 +Nd 4 +Nd 5 +Nd 6 )/6<( Nd 2 +Nd 3 )/2
wherein BFL is a distance from an image side surface of the sixth lens to an image plane along the optical axis, TTL is a distance from the convex surface of the first lens to the image plane along the optical axis, f is an effective focal length of the lens assembly, Nd 1 is an index of refraction of the first lens, Nd 2 is an index of refraction of the second lens, Nd 3 is an index of refraction of the third lens, Nd 4 is an index of refraction of the fourth lens, Nd 5 is an index of refraction of the fifth lens and Nd 6 is an index of refraction of the sixth lens.

2 . The lens assembly as claimed in claim 1 , wherein:
the second lens is a biconcave lens and with negative refractive power; the third lens is with positive refractive power and comprises a convex surface facing the object side; the fourth lens is a convex-concave lens with negative refractive power and comprises a convex surface facing the object side and a concave surface facing the image side; and the fifth lens further comprises a convex surface facing the object side.

3 . The lens assembly as claimed in claim 2 , wherein the sixth lens is with positive refractive power or the sixth lens is with negative refractive power.

4 . The lens assembly as claimed in claim 2 , wherein the lens assembly further satisfies:
0.01≦ f/TTL≦ 0.2
wherein f is an effective focal length of the lens assembly and TTL is a distance from the convex surface of the first lens to an image plane along the optical axis.

5 . The lens assembly as claimed in claim 2 , wherein the first lens and the second lens satisfy:
3≦ f 1 /f 2 ≦6
wherein f 1 is an effective focal length of the first lens and f 2 is an effective focal length of the second lens.

6 . The lens assembly as claimed in claim 2 , wherein the fourth lens satisfies:
0.54<| f 4 /f|< 20 wherein f 4 is an effective focal length of the fourth lens and f is an effective focal length of the lens assembly.

7 . The lens assembly as claimed in claim 2 , wherein the sixth lens satisfies:
−20≦ f 6 /f≦ 50
wherein f 6 is an effective focal length of the sixth lens and f is an effective focal length of the lens assembly.

8 . The lens assembly as claimed in claim 2 , wherein the third lens satisfies:
−10≦( R 31 −R 32 )/( R 31 +R 32 )≦5
wherein R 31 is a radius of curvature of the convex surface of the third lens and R 32 is a radius of curvature of an image side surface of the third lens.

9 . The lens assembly as claimed in claim 2 , wherein the fifth lens satisfies:
−70≦( R 51 −R 52 )/( R 51 +R 52 )≦20
wherein R 51 is a radius of curvature of the convex surface of the object side of the fifth lens and R 52 is a radius of curvature of the convex surface of the image side of the fifth lens.

10 . The lens assembly as claimed in claim 2 , wherein the convex surface of the first lens and the concave surface of the first lens are spherical surfaces.

11 . The lens assembly as claimed in claim 2 , wherein the first lens is made of glass material.

12 . The lens assembly as claimed in claim 2 , further comprising a stop disposed between the third lens and the fourth lens.

13 . The lens assembly as claimed in claim 1 , wherein:
the second lens is a biconvex lens and with positive refractive power; the third lens is with negative refractive power and comprises a concave surface facing the object side; the fourth lens is a biconvex lens and with positive refractive power; the fifth lens further comprises a concave surface facing the object side; and the sixth lens is with negative refractive power and comprises a convex surface facing the object side.

14 . The lens assembly as claimed in claim 13 , wherein:
the third lens further comprises a concave surface facing the image side; and the sixth lens further comprises a concave surface facing the image side.

15 . The lens assembly as claimed in claim 14 , wherein the lens assembly further satisfies:
0.4≦ f/TTL≦ 0.5
wherein f is an effective focal length of the lens assembly and TTL is a distance from the convex surface of the first lens to an image plane along the optical axis.

16 . The lens assembly as claimed in claim 14 , wherein the first lens and the sixth lens satisfy:
2≦ f 1 /f 6 ≦5
wherein f 1 is an effective focal length of the first lens and f 6 is an effective focal length of the sixth lens.

17 . The lens assembly as claimed in claim 14 , wherein the second lens satisfies:
−3≦( R 21 −R 22 )/( R 21 +R 22 )≦−1
wherein R 21 is a radius of curvature of an object side surface of the second lens and R 22 is a radius of curvature of an image side surface of the second lens.

18 . The lens assembly as claimed in claim 14 , wherein the fourth lens satisfies:
−1≦( R 41 −R 42 )/( R 41 +R 42 )≦20
wherein R 41 is a radius of curvature of an object side surface of the fourth lens and R 42 is a radius of curvature of an image side surface of the fourth lens.

19 . The lens assembly as claimed in claim 13 , wherein the first lens satisfies:
2.19 <|f 1 /f|< 2.74 wherein f 1 is an effective focal length of the first lens and f is an effective focal length of the lens assembly.

20 . The lens assembly as claimed in claim 13 , wherein the second lens satisfies:
0.53<| f 2 /f|< 1.03 wherein f 2 is an effective focal length of the second lens and f is an effective focal length of the lens assembly.

21 . The lens assembly as claimed in claim 13 , wherein the third lens satisfies:
0.72<| f 3 /f|< 1.37 wherein f 3 is an effective focal length of the third lens and f is an effective focal length of the lens assembly.

22 . The lens assembly as claimed in claim 13 , wherein the lens assembly further satisfies:
0.17<| BFL/TTL|< 0.20 wherein TTL is a distance from an object side surface of the first lens to an image plane along the optical axis and BFL is a distance from an image side surface of the sixth lens to the image plane along the optical axis.

23 . The lens assembly as claimed in claim 13 , further comprising a stop disposed between the first lens and the third lens.

24 . The lens assembly as claimed in claim 1 , wherein:
the second lens is a convex-concave lens with positive refractive power and comprises a convex surface facing the object side and a concave surface facing the image side; the third lens is a concave-convex lens with positive refractive power and comprises a concave surface facing the object side and a convex surface fa

Assignees

• Shih Po-Yuan
• Chen Po-Yu
• Sintai Optical Shenzhen Co Ltd
• Asia Optical Co Inc

Inventors

• Shih Po-Yuan
• Chen Po-Yu

Classifications

• G02B13/0045 Primary

  having five or more lenses · CPC title

• G02B9/62 Primary

  having six components only · CPC title

• G02B13/06

  Panoramic objectives; So-called "sky lenses" {including panoramic objectives having reflecting surfaces} · CPC title