Taking lens apparatus

• US 20040246362A1
• Filed: 07/29/2003
• Published: 12/09/2004
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: Minolta Co., Ltd. (Konica Minolta Inc.)
• Original Assignee: Minolta Co., Ltd. (Konica Minolta Inc.)
• Inventors: Konno, Kenji
• Granted Patent: US 7,079,325 B2
• Time in Patent Office: Days
• US Class Current: 348/335
• CPC Class Codes: G02B 15/143507 arranged -++
• CPC Class Codes: G02B 15/177 having a negative front lens or group of lenses
• CPC Class Codes: G02B 5/04 Prisms

Abstract

A taking lens apparatus has a zoom lens system that is composed of a plurality of lens units and that achieves zooming by varying the distances between the lens units and an image sensor that converts the optical image formed by the zoom lens system into an electrical signal. The zoom lens system has a first lens unit that is disposed at the object-side end of the zoom lens system, that has a negative optical power as a whole, that includes a reflective member for bending the optical axis of the zoom lens system as a whole at substantially 90°, and that remains stationary relative to the image sensor during the zooming of the zoom lens system, a second lens unit that is disposed on the image-sensor side of the first lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward the object side during the zooming of the zoom lens system from the wide-angle end to the telephoto end, and a third lens unit that is disposed on the image-sensor side of the second lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward the object side during the zooming of the zoom lens system.

Claims

1. A taking lens apparatus comprising:

a zoom lens system that is composed of a plurality of lens units and that achieves zooming by varying distances between the lens units; and

an image sensor that converts an optical image formed by the zoom lens system into an electrical signal;

wherein the zoom lens system comprises;

a first lens unit that is disposed at an object-side end of the zoom lens system, that has a negative optical power as a whole, and that remains stationary relative to the image sensor during zooming of the zoom lens system;

a second lens unit that is disposed on an image-sensor side of the first lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an object side during zooming of the zoom lens system from a wide-angle end to a telephoto end; and

a third lens unit that is disposed on an image-sensor side of the second lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an image side during initial zooming from the wide-angle end to the telelphoto end.

2. A taking lens apparatus as claimed in claim 1, wherein the third lens unit moves toward an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

3. A taking lens apparatus as claimed in claim 1, wherein the third lens unit moves along a U-shaped trajectory convex to an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

4. A taking lens apparatus as claimed in claim 1, wherein the first lens unit includes an aspherical surface.

5. A taking lens apparatus as claimed in claim 1, wherein an aperture stop is disposed between the first and second lens units.

6. A taking lens apparatus as claimed in claim 1, wherein an aperture stop is disposed between the second and third lens units.

7. A taking lens apparatus as claimed in claim 1, wherein the zoom lens system includes an aperture stop that moves together with the second lens unit during zooming.

8. A taking lens apparatus as claimed in claim 1, wherein the zoom lens system includes an aperture stop that remains stationary relative to an image plane during zooming.

9. A taking lens apparatus as claimed in claim 1, wherein the third lens unit is composed of a plurality of lens elements.

10. A taking lens apparatus as claimed in claim 1, wherein the following condition is fulfilled:

2.5<

Dref/Ymax<

4

where

Dref represents a sum of axial distances between an object-side optical component located immediately in front of the reflective member and an image-side optical component located immediately behind the reflective member; and

Ymax represents a maximum image height.

11. A taking lens apparatus as claimed in claim 1, wherein the following condition is fulfilled:

1.0<

(ft·

m2w)/(fw·

m2t)

where

fw represents a focal length of the zoom lens system as a whole at the wide-angle end;

ft represents a focal length of the zoom lens system as a whole at the telephoto end;

m2w represents an imaging magnification of the second lens unit at the wide-angle end; and

m2t represents an imaging magnification of the second lens unit at the telephoto end.

12. A taking lens apparatus as claimed in claim 1, wherein focusing is achieved by moving the third lens unit.

13. A taking lens apparatus as claimed in claim 1, wherein only one lens element is disposed on an object side of the reflective member.

14. A taking lens apparatus comprising:

a zoom lens system that is composed of a plurality of lens units and that achieves zooming by varying distances between the lens units; and

an image sensor that converts an optical image formed by the zoom lens system into an electrical signal;

wherein the zoom lens system comprises;

a first lens unit that is disposed at an object-side end of the zoom lens system, that has a negative optical power as a whole, that includes a reflective member for bending an optical axis of the zoom lens system as a whole at substantially 90°

, and that remains stationary relative to the image sensor during zooming of the zoom lens system;

a second lens unit that is disposed on an image-sensor side of the first lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an object side during zooming of the zoom lens system from a wide-angle end to a telephoto end; and

a third lens unit that is disposed on an image-sensor side of the second lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an image side during initial zooming from the wide-angle end to the telelphoto end.

15. A taking lens apparatus as claimed in claim 14, wherein the third lens unit moves toward an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

16. A taking lens apparatus as claimed in claim 14, wherein the third lens unit moves along a U-shaped trajectory convex to an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

17. A taking lens apparatus as claimed in claim 14, wherein the first lens unit includes an aspherical surface.

18. A taking lens apparatus as claimed in claim 14, wherein an aperture stop is disposed between the first and second lens units.

19. A taking lens apparatus as claimed in claim 14, wherein an aperture stop is disposed between the second and third lens units.

20. A taking lens apparatus as claimed in claim 14, wherein the zoom lens system includes an aperture stop that moves together with the second lens unit during zooming.

21. A taking lens apparatus as claimed in claim 14, wherein the zoom lens system includes an aperture stop that remains stationary relative to an image plane during zooming.

22. A taking lens apparatus as claimed in claim 14, wherein the third lens unit is composed of a plurality of lens elements.

23. A taking lens apparatus as claimed in claim 14, wherein the following condition is fulfilled:

2.5<

Dref/Ymax<

4

where

Dref represents a sum of axial distances between an object-side optical component located immediately in front of the reflective member and an image-side optical component located immediately behind the reflective member; and

Ymax represents a maximum image height.

24. A taking lens apparatus as claimed in claim 14, wherein the following condition is fulfilled:

1.0<

(ft·

m2w)/(fw·

m2t)

where

fw represents a focal length of the zoom lens system as a whole at the wide-angle end;

ft represents a focal length of the zoom lens system as a whole at the telephoto end;

m2w represents an imaging magnification of the second lens unit at the wide-angle end; and

m2t represents an imaging magnification of the second lens unit at the telephoto end.

25. A taking lens apparatus as claimed in claim 14, wherein focusing is achieved by moving the third lens unit.

26. A taking lens apparatus as claimed in claim 14, wherein only one lens element is disposed on an object side of the reflective member.

27. A camera comprising:

a taking lens apparatus including a zoom lens system that is composed of a plurality of lens units and that achieves zooming by varying distances between the lens units and an image sensor that converts an optical image formed by the zoom lens system into an electrical signal;

wherein the zoom lens system comprises;

a first lens unit that is disposed at an object-side end of the zoom lens system, that has a negative optical power as a whole, and that remains stationary relative to the image sensor during zooming of the zoom lens system;

a second lens unit that is disposed on an image-sensor side of the first lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an object side during zooming of the zoom lens system from a wide-angle end to a telephoto end; and

a third lens unit that is disposed on an image-sensor side of the second lens unit with a variable aerial distance secured in between, that has appositive optical power as a whole, and that moves toward an image side during initial zooming from the wide-angle end to the telelphoto end.

28. A camera as claimed in claim 27, wherein the third lens unit moves toward an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

29. A camera as claimed in claim 27, wherein the third lens unit moves along a U-shaped trajectory convex to an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

30. A camera as claimed in claim 27, wherein the first lens unit includes an aspherical surface.

31. A camera as claimed in claim 27, wherein an aperture stop is disposed between the first and second lens units.

32. A camera as claimed in claim 27, wherein an aperture stop is disposed between the second and third lens units.

33. A camera as claimed in claim 27, wherein the zoom lens system includes an aperture stop that moves together with the second lens unit during zooming.

34. A camera as claimed in claim 27, wherein the zoom lens system includes an aperture stop that remains stationary relative to an image plane during zooming.

35. A camera as claimed in claim 27, wherein the third lens unit is composed of a plurality of lens elements.

36. A camera as claimed in claim 27, wherein the following condition is fulfilled:

2.5<

Dref/Ymax<

4

where

Dref represents a sum of axial distances between an object-side optical component located immediately in front of the reflective member and an image-side optical component located immediately behind the reflective member; and

Ymax represents a maximum image height.

37. A camera as claimed in claim 27, wherein the following condition is fulfilled:

1.0<

(ft·

m2w)/(fw·

m2t)

where

fw represents a focal length of the zoom lens system as a whole at the wide-angle end;

ft represents a focal length of the zoom lens system as a whole at the telephoto end;

m2w represents an imaging magnification of the second lens unit at the wide-angle end; and

m2t represents an imaging magnification of the second lens unit at the telephoto end.

38. A camera as claimed in claim 27, wherein focusing is achieved by moving the third lens unit.

39. A camera as claimed in claim 27, wherein only one lens element is disposed on an object side of the reflective member.

40. A camera comprising:

a taking lens apparatus including a zoom lens system that is composed of a plurality of lens units and that achieves zooming by varying distances between the lens units and an image sensor that converts an optical image formed by the zoom lens system into an electrical signal;

wherein the zoom lens system comprises;

a first lens unit that is disposed at an object-side end of the zoom lens system, that has a negative optical power as a whole, that includes a reflective member for bending an optical axis of the zoom lens system as a whole at substantially 90°

, and that remains stationary relative to the image sensor during zooming of the zoom lens system;

a second lens unit that is disposed on an image-sensor side of the first lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an object side during zooming of the zoom lens system from a wide-angle end to a telephoto end; and

a third lens unit that is disposed on an image-sensor side of the second lens unit with a variable aerial distance secured in between, that has a positive optical power as a whole, and that moves toward an image side during initial zooming from the wide-angle end to the telelphoto end.

41. A camera as claimed in claim 40, wherein the third lens unit moves toward an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

42. A camera as claimed in claim 40, wherein the third lens unit moves along a U-shaped trajectory convex to an image side during zooming of the zoom lens system from the wide-angle end to the telephoto end.

43. A camera as claimed in claim 40, wherein the first lens unit includes an aspherical surface.

44. A camera as claimed in claim 40, wherein an aperture stop is disposed between the first and second lens units.

45. A camera as claimed in claim 40, wherein an aperture stop is disposed between the second and third lens units.

46. A camera as claimed in claim 40, wherein the zoom lens system includes an aperture stop that moves together with the second lens unit during zooming.

47. A camera as claimed in claim 40, wherein the zoom lens system includes an aperture stop that remains stationary relative to an image plane during zooming.

48. A camera as claimed in claim 40, wherein the third lens unit is composed of a plurality of lens elements.

49. A camera as claimed in claim 40, wherein the following condition is fulfilled:

2.5<

Dref/Ymax<

4

where

Dref represents a sum of axial distances between an object-side optical component located immediately in front of the reflective member and an image-side optical component located immediately behind the reflective member; and

Ymax represents a maximum image height.

50. A camera as claimed in claim 40, wherein the following condition is fulfilled:

1.0<

(ft·

m2w)/(fw·

m2t)

where

fw represents a focal length of the zoom lens system as a whole at the wide-angle end;

ft represents a focal length of the zoom lens system as a whole at the telephoto end;

m2w represents an imaging magnification of the second lens unit at the wide-angle end; and

m2t represents an imaging magnification of the second lens unit at the telephoto end.

51. A camera as claimed in claim 40, wherein focusing is achieved by moving the third lens unit.

52. A camera as claimed in claim 40, wherein only one lens element is disposed on an object side of the reflective member.