Teleconverter optical system

Patent metadata

Field	Value
Publication number	US-10627608-B2
Application number	US-201615392149-A
Country	US
Kind code	B2
Filing date	Dec 28, 2016
Priority date	Jan 27, 2016
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A converter optical system includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having negative refractive power; and a fifth lens having positive refractive power; wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the converter optical system to an image side of the converter optical system; and the fourth lens is bonded to either one or both of the third lens and the fifth lens.

First claim

What is claimed is:

1. A teleconverter optical system comprising:
a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power;
a fourth lens having negative refractive power; and
a fifth lens having positive refractive power;
wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the teleconverter optical system to an image side of the teleconverter optical system;
the fourth lens is bonded to either one or both of the third lens and the fifth lens;
an expression 1000<f/D is satisfied, where f is an overall focal length of the teleconverter optical system, and D is a distance from an object-side surface of the first lens to an image-side surface of the fifth lens; and
the teleconverter optical system has a magnification of two times or more.

2. The teleconverter optical system of claim 1 , wherein an expression 26<D<45 mm is satisfied.

3. The teleconverter optical system of claim 1 , wherein an expression f-number <2.0 is satisfied, where f-number is an f-number of the teleconverter optical system.

4. The teleconverter optical system of claim 1 , wherein the object-side surface of the first lens is convex.

5. The teleconverter optical system of claim 1 , wherein an image-side surface of the first lens is concave.

6. The teleconverter optical system of claim 1 , wherein an object-side surface of the second lens is convex.

7. The teleconverter optical system of claim 1 , wherein an image-side surface of the second lens is concave.

8. The teleconverter optical system of claim 1 , wherein both an object-side surface and an image-side surface of the fourth lens are concave.

9. The teleconverter optical system of claim 1 , wherein an object-side surface of the fifth lens is convex.

10. The teleconverter optical system of claim 1 , wherein the first to fifth lenses are the only lenses that have refractive power in the teleconverter optical system.

11. The teleconverter optical system of claim 1 , wherein an expression 1.55<n1<1.65 is satisfied, where n1 is a refractive index of the first lens.

12. A teleconverter optical system comprising:
a first lens having positive refractive power;
a second lens having refractive power;
a third lens having a convex object-side surface and a convex image-side surface;
a fourth lens having a concave object-side surface and a concave image-side surface; and
a fifth lens having refractive power;
wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the teleconverter optical system to an image side of the teleconverter optical system;
the image-side surface of the third lens is bonded to the object-side surface of the fourth lens;
an expression 1000<f/D is satisfied, where f is an overall focal length of the teleconverter optical system, and D is a distance from an object-side surface of the first lens to an image-side surface of the fifth lens; and
the teleconverter optical system has a magnification of two times or more.

13. The teleconverter optical system of claim 12 , wherein the first to fifth lenses are plastic lenses.

14. The teleconverter optical system of claim 12 , wherein absolute values of effective radii of the first to fifth lenses decrease as a distance of a lens from the object side of the teleconverter optical system increases so that an expression |r1|>|r2|>|r3|>|r4|>|r5| is satisfied, where r1 is the effective radius of the first lens, r2 is the effective radius of the second lens, r3 is the effective radius of the third lens, r4 is the effective radius of the fourth lens, and r5 is the effective radius of the fifth lens.

15. The teleconverter optical system of claim 12 , wherein an expression 1.55<n1<1.65 is satisfied, where n1 is a refractive index of the first lens.

16. A teleconverter optical system comprising:
a first lens having positive refractive power;
a second lens having negative refractive power;
a third lens having positive refractive power;
a fourth lens having negative refractive power; and
a fifth lens having positive refractive power;
wherein the first to fifth lenses are sequentially disposed in numerical order from the first lens to the fifth lens from an object side of the teleconverter optical system to an image side of the teleconverter optical system;
an expression 1000<f/D is satisfied, where f is an overall focal length of the teleconverter optical system, and D is a distance from an object-side surface of the first lens to an image-side surface of the fifth lens; and
an expression f-number <2.0 is satisfied, where f-number is an f-number of the teleconverter optical system.

17. The teleconverter optical system of claim 16 , wherein absolute values of effective radii of the first to fifth lenses decrease as a distance of a lens from the object side of the teleconverter optical system increases so that an expression |r1|>|r2|>|r3|>|r4|>|r5| is satisfied, where r1 is the effective radius of the first lens, r2 is the effective radius of the second lens, r3 is the effective radius of the third lens, r4 is the effective radius of the fourth lens, and r5 is the effective radius of the fifth lens.

18. The teleconverter optical system of claim 16 , wherein an image-side surface of the first lens is concave.

19. The teleconverter optical system of claim 16 , wherein an object-side surface of the fourth lens is concave.

20. The teleconverter optical system of claim 16 , wherein the image-side surface of the fifth lens is convex.

21. The teleconverter optical system of claim 16 , wherein an expression 1.55<n1<1.65 is satisfied, where n1 is a refractive index of the first lens.

22. The teleconverter optical system of claim 16 , wherein an expression 26<D<45 mm is satisfied.

23. The teleconverter optical system of claim 16 , wherein the teleconverter optical system has a magnification of two times or more.

Assignees

• Samsung Electro Mech

Inventors

• Ko Jung Hui

Classifications

• G02B13/18

  with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)} · CPC title

• G02B13/0045 Primary

  having five or more lenses · CPC title

• G02B13/001

  Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras (G02B23/243 takes precedence) · CPC title

• G02B15/12 Primary

  by adding telescopic attachments (G02B15/14 takes precedence) · CPC title