Imaging lens unit

Patent metadata

Field	Value
Publication number	US-9523839-B2
Application number	US-201414473938-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Oct 10, 2011
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

Disclosed herein is an imaging lens unit, including: a first lens having a positive (+) power; a second lens having a negative (−) power; a third lens selectively having one of a positive (+) and negative (−) power; a fourth lens having a negative (−) power; and a fifth lens having a negative (−) power, wherein the first lens, the second lens, the third lens, the fourth lens, and fifth lens are arranged in order from an object to be formed as an image, and the fourth lens is concave toward an image side.

First claim

What is claimed is:

1. An image lens unit, comprising:
a first lens having positive (+) power and being convex toward an object side;
a second lens having negative (−) power and being concave toward an image side;
a third lens having positive (+) power and being concave near an axial perimeter toward the object side;
a fourth lens having negative (−) power and a meniscus shape being concave in the center toward the object side and convex toward the image side; and
a fifth lens having a refractive power and being convex toward the object side and concave toward the image side,
wherein:
an Abbe number v 2 of the second lens satisfies the following conditional expression:
0<v2<30,

at least one inflection point is formed on an image-side surface of the fifth lens, and
the first lens, the second lens, the third lens, the fourth lens and the fifth lens are arranged in order from the object side toward the image side.

2. The image lens unit of claim 1 , wherein:
an object-side surface of the fifth lens is convex in the center and concave at the periphery, and
the image-side surface of the fifth lens is concave in the center and convex at the periphery.

3. The image lens unit of claim 2 , wherein the third lens is convex toward the image side.

4. The image lens unit of claim 1 , wherein an Abbe number v 1 of the first lens satisfies the following conditional expression:
50<v1.

5. The image lens unit of claim 4 , wherein an Abbe number v 4 of the fourth lens satisfies the following conditional expression:
0<v4<30.

6. The image lens unit of claim 5 , wherein the Abbe number v 1 of the first lens, the Abbe number v 2 of the second lens, an Abbe number v 3 of the third lens, and the Abbe number v 4 of the fourth lens satisfy the following conditional expression:
0.7<( v 1+ v 2)/( v 3+ v 4)≦1.0.

7. The image lens unit of claim 1 , wherein a total focal length f of the imaging lens unit and a distance tt on an optical axis from an object-side surface of the first lens to an imaging sensor satisfy the following conditional expression:
0< tt/f< 1.3.

8. The image lens unit of claim 1 , wherein the second lens, the third lens, and the fourth lens are made of a plastic material.

9. The image lens unit of claim 8 , wherein the first lens is made of a plastic material.

10. The image lens unit of claim 1 , wherein the second lens and the fourth lens are formed of a high dispersion material.

11. The image lens unit of claim 1 , further comprising an aperture stop disposed in front of the first lens.

12. The image lens unit of claim 1 , wherein a focal length of the first lens is greater than a focal length of the second lens.

13. The image lens unit of claim 12 , wherein the focal length of the second lens is greater than a focal length of the fourth lens.

14. The image lens unit of claim 1 , wherein the second lens has the thinnest thickness among the first lens, the second lens, the third lens, the fourth lens and the fifth lens.

15. An image lens unit, comprising:
a first lens having positive (+) power and being convex toward an object side;
a second lens having negative (−) power and being concave toward an image side;
a third lens having positive (+) power and being concave near an axial perimeter toward the object side and convex toward the image side;
a fourth lens having negative (−) power and being concave in the center toward the object side and convex toward the image side; and
a fifth lens having a refractive power and comprising:
an object-side surface being convex in the center and concave at the periphery; and
an image-side surface being concave in the center and convex at the periphery, wherein:
an Abbe number v 2 of the second lens and an Abbe number v 4 of the fourth lens satisfy the following conditional expressions:
0<v2<30
0<v4<30

the third and fourth lenses have a meniscus shape, and
the first lens, the second lens, the third lens, the fourth lens and the fifth lens are arranged in order from the object side toward the image side.

16. The image lens unit of claim 15 , wherein an Abbe number v 1 of the first lens satisfies the following conditional expression:
50<v1.

17. The image lens unit of claim 16 , wherein the Abbe number v 1 of the first lens, the Abbe number v 2 of the second lens, an Abbe number v 3 of the third lens, and the Abbe number v 4 of the fourth lens satisfy the following conditional expression:
0.7<( v 1+ v 2)/( v 3+ v 4)≦1.0.

18. The image lens unit of claim 15 , wherein a total focal length f of the imaging lens unit and a distance tt on an optical axis from an object-side surface of the first lens to an imaging sensor satisfy the following conditional expression:
0< tt/f< 1.3.

19. The image lens unit of claim 15 , wherein the second lens, the third lens, and the fourth lens are made of a plastic material.

20. The image lens unit of claim 19 , wherein the first lens is made of a plastic material.

21. The image lens unit of claim 15 , wherein the second lens and the fourth lens are formed of a high dispersion material.

22. The image lens unit of claim 15 , further comprising an aperture stop disposed in front of the first lens.

23. The image lens unit of claim 15 , wherein a focal length of the first lens is greater than a focal length of the second lens.

24. The image lens unit of claim 23 , wherein the focal length of the second lens is greater than a focal length of the fourth lens.

25. The image lens unit of claim 15 , wherein the second lens has the thinnest thickness among the first lens, the second lens, the third lens, the fourth lens and the fifth lens.

Assignees

• Samsung Electro Mech

Inventors

• You Ho Sik

Classifications

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B13/0045 Primary

  having five or more lenses · CPC title

• G02B9/60 Primary

  having five components only · CPC title

• G02B13/0015

  characterised by the lens design · CPC title

• G02B2003/0093

  characterised by the shape · CPC title