IP Library › Granted Patent US 7,164,540
Granted Patent B2
US 7,164,540 · App. 11/081,497 · Granted Jan 16, 2007

Zoom lens system

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Quick Facts
Patent No.
US 7,164,540
App. No.
11/081,497
Granted
Jan 16, 2007
Kind
B2
Abstract

A zoom lens system includes ‘n’ (n≧3) lens groups. A first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of the zoom lens system has a negative refractive power. The distance from the most object-side surface of the positive first lens group to the most image-side surface of the negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity.

Claims (133)

1. A zoom lens system comprising ‘n’ (n≧3) lens groups,

wherein a first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of said zoom lens system has a negative refractive power;

wherein the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity; and

wherein the zoom lens system satisfies the following condition:

1.0 <f M /f W <3.0

wherein

f M designates an intermediate focal length of said zoom lens system at which the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

2. The zoom lens system according to claim 1 , satisfying the following condition:

0.3<( LD W −LD M )/( f T /f W )<1.0

wherein

LD W designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the short focal length extremity;

LD M designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the intermediate focal length f M ; and

f T designates the focal length of said zoom lens system at the long focal length extremity.

3. The zoom lens system according to claim 1 , satisfying the following condition:

0< LD T −LD W

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity; and

LD W designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the short focal length extremity.

4. The zoom lens system according to claim 1 , satisfying the following condition:

0.3<( LD T −LD W )/( f T /f W )<0.9

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity;

LD W designates the distance from the most object-side surface of the positive first lens group to the most image-side surface of the negative final lens group, at the short focal length extremity; and

f T designates the focal length of said zoom lens system at the long focal length extremity.

5. The zoom lens system according to claim 1 , satisfying the following condition:

3 <f T /f W

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity.

6. The zoom lens system according to claim 1 , wherein said zoom lens system comprises three lens groups (n=3); and

wherein said three lens groups comprise said positive first lens group, a positive second lens group, and said negative final lens group, in this order from an object.

7. The zoom lens system according to claim 1 , wherein said zoom lens system comprises four lens groups (n=4); and

wherein said four lens groups comprise said positive first lens group, a negative second lens group, a positive third lens group, and said negative final lens group, in this order from an object.

8. The zoom lens system according to claim 7 , satisfying the following condition:

1.2 <f M /f W <3.0.

9. The zoom lens system according to claim 7 , satisfying the following condition:

0.3<( LD T −LD W )/( f T /f W )<0.7

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative fourth lens group, at the long focal length extremity;

LD W designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative fourth lens group, at the short focal length extremity; and

f T designates the focal length of said zoom lens system at the long focal length extremity.

10. The zoom lens system according to claim 7 , satisfying the following condition:

0.3<( d 23W −d 23T )/( f T /f W )<1.5

wherein

d 23W designates the axial distance between said negative second lens group and said positive third lens group at the short focal length extremity;

d 23T designates the axial distance between said negative second lens group and said positive third lens group at the long focal length extremity; and

f T designates the focal length of said zoom lens system at the long focal length extremity.

11. The zoom lens system according to claim 7 , satisfying the following condition:

−12< f T /f 2G <−9

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f 2G designates the focal length of said negative second lens group.

12. The zoom lens system according to claim 7 , satisfying the following condition:

1.05< h 3G /h 1<1.30

wherein

h 3G designates the height of a paraxial light ray incident on the final surface of said positive third lens group; and

h 1 designates the height of a paraxial light ray incident on the first surface of said positive first lens group.

13. The zoom lens system according to claim 7 , satisfying the following condition:

4.5< f T /f W

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity.

14. A zoom lens system comprising ‘n’ (n≧3) lens groups,

wherein a first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of said zoom lens system has a negative refractive power;

wherein the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity; and

wherein the zoom lens system satisfies the following condition:

0.3<( LD W −LD M )/( f T /f W )<1.0

wherein

LD W designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the short focal length extremity;

LD M designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the intermediate focal length f M ;

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

15. The zoom lens system according to claim 14 , satisfying the following condition:

0 <LD T −LD W

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity.

16. The zoom lens system according to claim 14 , satisfying the following condition:

0.3<( LD T −LD W )/( f T /f W )<0.9

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity.

17. The zoom lens system according to claim 14 , satisfying the following condition:

3 <f T /f W .

18. The zoom lens system according to claim 14 , wherein said zoom lens system comprises three lens groups (n=3); and

wherein said three lens groups comprise said positive first lens group, a positive second lens group, and said negative final lens group, in this order from an object.

19. The zoom lens system according to claim 14 , wherein said zoom lens system comprises four lens groups (n=4); and

wherein said four lens groups comprise said positive first lens group, a negative second lens group, a positive third lens group, and said negative final lens group, in this order from an object.

20. A zoom lens system comprising ‘n’ (n≧3) lens groups,

wherein a first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of said zoom lens system has a negative refractive power;

wherein the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity; and

wherein the zoom lens system satisfies the following condition:

0 <LD T −LD W

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity; and

LD W designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the short focal length extremity.

21. The zoom lens system according to claim 20 , satisfying the following condition:

0.3<( LD T −LD W )/( f T /f W )<0.9

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

22. The zoom lens system according to claim 20 , satisfying the following condition:

3 <f T /f W

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

23. The zoom lens system according to claim 20 , wherein said zoom lens system comprises three lens groups (n=3); and

wherein said three lens groups comprise said positive first lens group, a positive second lens group, and said negative final lens group, in this order from an object.

24. The zoom lens system according to claim 20 , wherein said zoom lens system comprises four lens groups (n=4); and

wherein said four lens groups comprise said positive first lens group, a negative second lens group, a positive third lens group, and said negative final lens group, in this order from an object.

25. A zoom lens system comprising ‘n’ (n≧3) lens groups,

wherein a first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of said zoom lens system has a negative refractive power;

wherein the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity; and

wherein the zoom lens system satisfies the following condition:

0.3<( LD T −LD W )/( f T /f W )<0.9

wherein

LD T designates the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group, at the long focal length extremity;

LD W designates the distance from the most object-side surface of the positive first lens group to the most image-side surface of the negative final lens group, at the short focal length extremity;

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

26. The zoom lens system according to claim 25 , satisfying the following condition:

3 <f T /f W .

27. The zoom lens system according to claim 25 , wherein said zoom lens system comprises three lens groups (n=3); and

wherein said three lens groups comprise said positive first lens group, a positive second lens group, and said negative final lens group, in this order from an object.

28. The zoom lens system according to claim 25 , wherein said zoom lens system comprises four lens groups (n=4); and

wherein said four lens groups comprise said positive first lens group, a negative second lens group, a positive third lens group, and said negative final lens group, in this order from an object.

29. A zoom lens system comprising ‘n’ (n≧3) lens groups,

wherein a first lens group that is the most object-side lens group of said zoom lens system has a positive refractive power, and a final lens group that is the most image-side lens group of said zoom lens system has a negative refractive power;

wherein the distance from the most object-side surface of said positive first lens group to the most image-side surface of said negative final lens group becomes shortest at an intermediate focal length between the short focal length extremity and the long focal length extremity;

wherein said zoom lens system comprises three lens groups (n=3); and

wherein said three lens groups comprise said positive first lens group, a positive second lens group, and said negative final lens group, in this order from an object.

30. The zoom lens system according to claim 29 , satisfying the following condition:

3 <f T /f W

wherein

f T designates the focal length of said zoom lens system at the long focal length extremity; and

f W designates the focal length of said zoom lens system at the short focal length extremity.

Assignments (2)
CORPORATE SPLIT Recorded Dec 2, 2011
From: HOYA CORPORATION
To: PENTAX RICOH IMAGING COMPANY, LTD.
Reel/Frame 027315/0115 →
MERGER Recorded Sep 26, 2011
From: PENTAX CORPORATION
To: HOYA CORPORATION
Reel/Frame 026970/0554 →