Photographing lens Number:7,167,644 from the United States Patent and Trademark Office (PTO) owispatent A lens barrel includes a housing having a ring portion surrounding an optical axis; a first optical element and a second optical element which are positioned inside the ring portion and which are movable along the optical axis relative to the housing; a support frame which supports the second optical element, and has at least one arm portion which projects radially outwards to such an extent that an outer end of the arm portion is positioned radially outside the ring portion of the housing; and at least one guide shaft positioned radially outside the ring portion, and configured to guide the arm portion in the optical axis direction.<H Photographing, lens, Photographing, l, 7167644.html, Patent, pto, 7167644

Title: Photographing lens

Abstract: A lens barrel includes a housing having a ring portion surrounding an optical axis; a first optical element and a second optical element which are positioned inside the ring portion and which are movable along the optical axis relative to the housing; a support frame which supports the second optical element, and has at least one arm portion which projects radially outwards to such an extent that an outer end of the arm portion is positioned radially outside the ring portion of the housing; and at least one guide shaft positioned radially outside the ring portion, and configured to guide the arm portion in the optical axis direction.

Patent Number: 7,167,644 Issued on 01/23/2007 to Nomura

Inventors: Nomura; Hiroshi (Saitama, JP)
Assignee: PENTAX Corporation (Tokyo, JP)

Appl. No.: 11/287,282

Filed: November 28, 2005

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
10646812	Aug., 2003	6990291

Foreign Application Priority Data


Aug 27, 2002 [JP]			2002-247338
Feb 03, 2003 [JP]			2003-25444

Current U.S. Class: 396/73 ; 396/350

Current International Class: G03B 17/00 (20060101); G03B 5/06 (20060101)

Field of Search: 396/72,73,348,349,350 359/699,700,701

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Primary Examiner: Mahoney; Christopher
Attorney, Agent or Firm: Greenblum & Bernstein, P.L.C.

Parent Case Text

This application is a continuation of pending U.S. patent application Ser. No. 10/646,812, filed Aug. 25, 2003 now U.S. Pat. No. 6,990,291, the disclosure of which is expressly incorporated herein by reference in its entirety.

Claims

What is claimed is:

1. A lens barrel comprising: a housing having a ring portion surrounding an optical axis; a first optical element and a second optical element which are positioned inside said ring portion and which are movable along said optical axis relative to said housing; a support frame which supports said second optical element, and has at least one arm portion which projects radially outwards to such an extent that an outer end of said arm portion is positioned radially outside said ring portion of said housing; and at least one guide shaft positioned radially outside said ring portion, and configured to guide said arm portion in said optical axis direction.

2. The lens barrel according to claim 1, wherein the lens barrel is a retractable lens barrel, wherein said support frame comprises a ring-shaped portion which holds said second optical element, said arm portion projecting radially outwards from a rear end of said ring-shaped portion, and wherein said first optical element is positioned radially outside said ring-shaped portion of said support frame, and between said ring-shaped portion of said support frame and said ring portion of said housing when said lens barrel is in a retracted state.

3. The lens barrel according to claim 2, wherein said ring-shaped portion is a substantially rectangular ring shape.

4. The lens barrel according to claim 1, wherein said arm portion comprises a pair of arm portions which project radially outwards to be positioned on substantially opposite sides of an optical axis of said second optical element.

5. The lens barrel according to claim 1, further comprising: at least one third optical element positioned behind said second optical element; and a rear-end cover fixed to a rear end of said ring portion of said housing and substantially covering said rear end of said ring portion, and further supporting said third optical element on a front side of said rear-end cover; wherein said housing includes at least one radial projection which projects radially outwards from said ring portion of said housing, and wherein said radial projection and said rear-end cover have front and rear shaft-supporting holes which oppose each other in said optical axis direction to support opposite ends of said at least one guide shaft, respectively.

6. The lens barrel according to claim 5, wherein said third optical element comprises an image pick-up device.

7. The lens barrel according to claim 1, wherein said first optical element and said second optical element comprise a front lens group and a rear lens group, respectively.

8. The lens barrel according to claim 7, further comprising a lens group positioned in front of said front lens group, wherein said lens group and said front lens group are configured to be moved along said optical axis while changing a distance therebetween to vary a focal length in an operating state of said lens barrel.

9. The lens barrel according to claim 8, wherein the lens barrel is a retractable lens barrel, and wherein said lens group, which is positioned in front of said front lens group, is positioned closer to said rear lens group in a retracted state of said lens barrel than said operating state of said lens barrel.

10. The lens barrel according to claim 7, wherein said rear lens group is movable along said optical axis via said support frame and said guide shaft to perform a focusing operation.

11. The lens barrel according to claim 1, wherein the lens barrel is fixed to a camera body, wherein said camera body comprises an LCD panel positioned behind said support frame in said optical axis direction, and wherein said guide shaft extends in said optical axis direction such that at least a portion of said guide shaft overlaps said LCD panel in a radial direction of said optical axis.

12. The lens barrel according to claim 11, wherein a rear end of said guide shaft is extended rearward to a position radially outside said LCD panel.

13. The lens barrel according to claim 1, wherein said housing is a stationary barrel fixed to a camera body.

14. The lens barrel according to claim 1, further comprising at least four optical elements including said first optical element and said second optical element, wherein said four optical elements include a third optical element and a fourth optical element which are positioned behind said second optical element and in front of said first optical element, respectively.

15. The lens barrel according to claim 1, wherein said first optical element and said second optical element are positioned radially inside said ring portion.

16. The lens barrel according to claim 1, further comprising an annular member configured to move said first optical element along the optical axis, wherein said at least one guide shaft is further positioned radially outside of said annular member.

17. The lens barrel according to claim 1, further comprising a third optical element.

18. The lens barrel according to claim 17, wherein said third optical element and said first optical element comprise a forward lens group and a rearward lens group, respectively.

19. The lens barrel according to claim 18, further comprising a fourth optical element positioned forwardly of said forward lens group.

20. The lens barrel according to claim 19, wherein: said fourth optical element comprises a fourth optical element lens group; and said fourth optical element lens group and said forward lens group are configured to be moved along said optical axis while changing a distance therebetween to vary a focal length in an operating state of said lens barrel.

21. The lens barrel according to claim 20, wherein said fourth optical element lens group is positioned closer to said rearward lens group in a retracted state of said lens barrel than said operating state of said lens barrel.

22. The lens barrel according to claim 17, wherein the lens barrel is a retractable lens barrel.

23. The lens barrel according to claim 22, wherein said support frame comprises a ring-shaped portion which holds said first optical element, said arm portion projecting outwards from a rear end of said ring-shaped portion.

24. The lens barrel according to claim 23, wherein said third optical element is positioned outside said ring-shaped portion of said support frame, and between said ring-shaped portion of said support frame and said ring portion of said housing when said lens barrel is in a retracted state.

25. A digital camera comprising: a body; an image pick-up device disposed within the body; a housing disposed within said body and having a ring portion surrounding an optical axis; a first optical element and a second optical element which are positioned inside said ring portion and which are movable along said optical axis relative to said housing; a support frame which supports said second optical element, and has at least one arm portion which projects radially outwards to such an extent that an outer end of said arm portion is positioned radially outside said ring portion of said housing; and at least one guide shaft positioned radially outside said ring portion, and configured to guide said arm portion in said optical axis direction.

26. The camera according to claim 25, further comprising a retractable lens barrel, wherein said support frame comprises a ring-shaped portion which holds said second optical element, said arm portion projecting radially outwards from a rear end of said ring-shaped portion, and wherein said first optical element is positioned radially outside said ring-shaped portion of said support frame, and between said ring-shaped portion of said support frame and said ring portion of said housing when said retractable lens barrel is in a retracted state.

27. The camera according to claim 25, wherein said arm portion comprises a pair of arm portions which project radially outwards to be positioned on substantially opposite sides of an optical axis of said second optical element.

28. The camera according to claim 25, wherein said image pick-up device is positioned behind said second optical element, the camera further comprising a rear-end cover fixed to a rear end of said ring portion of said housing and substantially covering said rear end of said ring portion, and further supporting said image pick-up device on a front side of said rear-end cover; wherein said housing includes at least one radial projection which projects radially outwards from said ring portion of said housing, and wherein said radial projection and said rear-end cover have front and rear shaft-supporting holes which oppose each other in said optical axis direction to support opposite ends of said at least one guide shaft, respectively.

29. The camera according to claim 25, wherein said first optical element and said second optical element comprise a front lens group and a rear lens group, respectively.

30. The camera according to claim 29, further comprising a lens group positioned in front of said front lens group, wherein said lens group and said front lens group are configured to be moved along said optical axis while changing a distance therebetween to vary a focal length in an operating state of the camera.

31. The camera according to claim 30, further comprising a retractable lens barrel, and wherein said lens group, which is positioned in front of said front lens group, is positioned closer to said rear lens group in a retracted state of said retractable lens barrel than said operating state of said retractable lens barrel.

32. The camera according to claim 25, further comprising a lens barrel attached to said body; wherein said camera body comprises an LCD panel positioned behind said support frame in said optical axis direction, and wherein said guide shaft extends in said optical axis direction such that at least a portion of said guide shaft overlaps said LCD panel in a radial direction of said optical axis.

33. The camera according to claim 25, wherein said housing is a stationary barrel fixed to said camera body.

34. The camera according to claim 25, further comprising at least four optical elements including said first optical element and said second optical element, wherein said four optical elements include a third optical element and a fourth optical element which are positioned behind said second optical element and in front of said first optical element, respectively.

35. The lens barrel according to claim 25, wherein said first optical element and said second optical element are positioned radially inside said ring portion.

36. The lens barrel according to claim 25, further comprising an annular member configured to move said first optical element along the optical axis, wherein said at least one guide shaft is further positioned radially outside of said annular member.

37. A lens barrel comprising: a housing having a ring portion surrounding an optical axis; an optical element positioned inside said ring portion; and a support frame configured to support said optical element, said support frame comprising at least one arm portion which projects outwards such that an end of said arm portion is positioned outside said ring portion of said housing; and at least one guide shaft positioned outside said ring portion, said at least one guide shaft configured to guide said arm portion such that said optical element is movable along the optical axis relative to the housing.

38. The lens barrel according to claim 37, wherein said at least one arm portion comprises at least one sleeve through which said at least one guide shaft extends, said at least one sleeve extending for at least half of a length of said at least one guide shaft.

39. The lens barrel according to claim 37, wherein said arm portion comprises a pair of arm portions which project radially outwards to be positioned on substantially opposite sides of an optical axis of said optical element.

40. The lens barrel according to claim 37, wherein said ring portion is a substantially rectangular ring shape.

41. The lens barrel according to claim 37, wherein said optical element is a focusing lens.

42. The lens barrel according to claim 37, wherein said optical element is a first optical element, the lens barrel further comprising: a second optical element positioned behind said first optical element; and a rear-end cover fixed to a rear end of said ring portion of said housing and substantially covering said rear end of said ring portion, and further supporting said second optical element on a front side of said rear-end cover; wherein said housing includes at least one projection which projects outwards from said ring portion of said housing, and wherein said projection and said rear-end cover have front and rear shaft-supporting holes which oppose each other in said optical axis direction to support opposite ends of said at least one guide shaft, respectively.

43. The lens barrel according to claim 42, wherein said second optical element comprises an image pick-up device.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photographing (imaging) lens (lens barrel), more specifically to a mechanism thereof for supporting one or more optical elements and for guiding the same along the optical axis of the photographing lens.

2. Description of the Related Art

In a conventional lens barrel in which various elements thereof are installed inside a housing (stationary barrel) of the lens barrel that serves as an outermost wall of the lens barrel, a mechanism for supporting one or more optical elements such as a lens group and for guiding such optical elements along the optical axis of the lens barrel is entirely positioned in the housing.

Due to this structure, such a supporting and guiding mechanism becomes an obstacle to a reduction of the length of the lens barrel if the lens barrel is designed so that the length thereof becomes smaller in an non-operating state of the lens barrel than in an operating state of the lens barrel, i.e., if the lens barrel is designed to be a retractable lens barrel. Namely, the supporting and guiding mechanism makes it difficult to reduce the length of the lens barrel.

SUMMARY OF THE INVENTION

The present invention provides a lens barrel having a mechanism for supporting one or more optical elements and for guiding such optical elements along the optical axis of the lens barrel, wherein the mechanism has a structure making it possible to reduce the size of the lens barrel, especially the length thereof in the optical axis direction, and can guide the optical element with a high degree of travel accuracy.

According to an aspect of the present invention, a lens barrel is provided, including a housing having a ring portion surrounding an optical axis; a first optical element and a second optical element which are positioned radially inside the ring portion and which are movable along the optical axis relative to the housing; a support frame which supports the second optical element, and has at least one radial arm portion which projects radially outwards to such an extent that an outer end of the radial arm portion is positioned radially outside the ring portion of the housing; and at least one guide shaft positioned radially outside the ring portion, and configured to guide the radial arm portion in the optical axis direction.

The lens barrel can be a retractable lens barrel, and the support frame can include a ring-shaped portion which holds the second optical element, the radial arm portion projecting radially outwards from a rear end of the ring-shaped portion. It is desirable for the first optical element to be positioned radially outside the ring-shaped portion of the support frame, and between the ring-shaped portion of the support frame and the ring portion of the housing when the lens barrel is in a retracted state.

The radial arm portion can include a pair of radial arm portions which project radially outwards to be positioned on substantially opposite sides of an optical axis of the second optical element.

The lens barrel can further include at least one third optical element positioned behind the second optical element; and a rear-end cover fixed to a rear end of the ring portion of the housing and substantially covering the rear end of the ring portion, and further supporting the third optical element on a front side of the rear-end cover. The housing can include at least one radial projection which projects radially outwards from the ring portion of the housing. The radial projection and the rear-end cover can have front and rear shaft-supporting holes which oppose each other in the optical axis direction to support opposite ends of the at least one guide shaft, respectively.

The third optical element can be an image pick-up device.

The first optical element and the second optical element can be a front lens group and a rear lens group, respectively.

The lens barrel can further include a lens group positioned in front of the front lens group. The lens group and the front lens group can be configured to be moved along the optical axis while changing a distance therebetween to vary a focal length in an operating state of the lens barrel.

It is desirable for the lens barrel to be a retractable lens barrel, and for the lens group, which is positioned in front of the front lens group, to be positioned closer to the rear lens group in a retracted state of the lens barrel than the operating state of the lens barrel.

It is desirable for the rear lens group to be movable along the optical axis via the support frame and the guide shaft to perform a focusing operation.

It is desirable for the lens barrel to be fixed to a camera body. The camera body can include an LCD panel positioned behind the support frame in the optical axis direction. The guide shaft can extend in the optical axis direction such that at least a portion of the guide shaft overlaps the LCD panel in a radial direction of the optical axis.

It is desirable for a rear end of the guide shaft to be extended rearward to a position radially outside the LCD panel.

The housing can be a stationary barrel fixed to a camera body.

The lens barrel can further include at least four optical elements including the first optical element and the second optical element. The four optical elements can include a third optical element and a fourth optical element which are positioned behind the second optical element and in front of the first optical element, respectively.

It is desirable for the ring-shaped portion to be a substantially rectangular ring shape.

In another embodiment, a lens barrel is provided, including a photographing optical system including a first optical element and a second optical element; a stationary barrel including a ring positioned around an optical axis of the photographing optical system, the first optical element and the second optical element positioned radially inside the ring and configured to be guided along the optical axis relative to the ring; a linearly movable frame positioned behind the ring, the linearly movable frame including a lens holder which holds the second optical element, and a pair of radial arm portions which project radially outwards from the lens holder in substantially opposite directions away from each other to such an extent that respective outer ends of the pair of radial arm portions are positioned radially outside the ring; and a pair of guide shafts positioned radially outside the ring and configured to guide the pair of radial arm portions in the optical axis direction, respectively.

The present disclosure relates to subject matter contained in Japanese Patent Application Nos. 2002-247338 (filed on Aug. 27, 2002) and 2003-25444 (filed on Feb. 3, 2003) which are expressly incorporated herein by reference in their entireties.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described below in detail with reference to the accompanying drawings in which:

FIG. 1 is an exploded perspective view of an embodiment of a zoom lens according to the present invention;

FIG. 2 is an exploded perspective view of a structure supporting a first lens group of the zoom lens;

FIG. 3 is an exploded perspective view of a structure supporting a second lens group of the zoom lens;

FIG. 4 is an exploded perspective view of a lens barrel advancing-retracting structure of the zoom lens for advancing and retracting a third external barrel from a stationary barrel;

FIG. 5 is a perspective view, partly exploded, of the zoom lens, showing a fixing procedure of a viewfinder unit to the zoom lens and a fixing procedure of a gear train to the zoom lens;

FIG. 6 is a perspective view of a zoom lens assembly made from the elements shown in FIG. 5;

FIG. 7 is a side elevational view of the zoom lens assembly shown in FIG. 6;

FIG. 8 is a perspective view of the zoom lens assembly shown in FIG. 6, viewed obliquely from behind;

FIG. 9 is an axial cross sectional view of an embodiment of a digital camera incorporating the zoom lens assembly shown in FIGS. 6 through 8, wherein an upper half above a photographing optical axis and a lower half below the photographing optical axis show a state of the zoom lens at telephoto extremity and a state of the zoom lens at wide-angle extremity, respectively;

FIG. 10 is an axial cross sectional view of the digital camera shown in FIG. 9 in the retracted state of the zoom lens;

FIG. 11 is a developed view of the stationary barrel shown in FIG. 1;

FIG. 12 is a developed view of a helicoid ring shown in FIG. 4;

FIG. 13 is a developed view of the helicoid ring shown in FIG. 1, showing a structure of the inner peripheral surface thereof by broken lines;

FIG. 14 is a developed view of the third external barrel shown in FIG. 1;

FIG. 15 is a developed view of a first linear guide ring shown in FIG. 1;

FIG. 16 is a developed view of a cam ring shown in FIG. 1;

FIG. 17 is a developed view of the cam ring shown in FIG. 1, showing a structure of the inner peripheral surface thereof by broken lines;

FIG. 18 is a developed view of a second linear guide ring shown in FIG. 1;

FIG. 19 is a developed view of a second lens group moving frame shown in FIG. 1;

FIG. 20 is a developed view of a second external barrel shown in FIG. 1;

FIG. 21 is a developed view of a first external barrel shown in FIG. 1;

FIG. 22 is a conceptual diagram of elements of the zoom lens, showing the relationship among these elements in relation to the operations thereof;

FIG. 23 is a developed view of the helicoid ring, the third external barrel and the stationary barrel, showing the positional relationship thereamong in the retracted state of the zoom lens;

FIG. 24 is a developed view of the helicoid ring, the third external barrel and the stationary barrel, showing the positional relationship thereamong at the wide-angle extremity the zoom lens;

FIG. 25 is a developed view of the helicoid ring, the third external barrel and the