JP3255454B2 - Lens storage structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for storing a lens such as a photographing lens for a camera.

[0002]

2. Description of the Related Art Generally, it is desirable that a camera be as compact as possible when not photographing. For example, with a zoom lens camera,
It is desirable that the lens barrel can be further shortened from the position where the lens barrel becomes the shortest within the zooming range. Here, in the conventional zoom lens, a plurality of lens groups are brought into contact with each other in the optical axis direction by a cam mechanism formed by a combination of a cam groove formed in a cam ring and a cam follower member (pin or roller) engaged with the cam groove. Moving away and zooming. Therefore, in the conventional zoom lens, a housing groove for shortening (housing) is formed by extending from an end of the zooming groove, and the lens barrel length is further reduced by driving the lens in the housing groove. .

However, when the storage groove is extended from the end of the zooming groove, the storage groove may interfere with another adjacent cam groove, or even if there is no interference, there is no space for extending the cam groove. is there. In such a case, the circumference of the cam ring or the length in the optical axis direction must be increased, which hinders compactness. Further, when the storage groove extends in the opposite direction from the end of the zooming groove (has an inflection point), it is difficult to make the storage groove continuous with the zooming groove. Further, when the cam follower reaches the end of the zooming groove and is used as, for example, reference position information of the lens, the cam follower must be stopped at the end of the zooming groove without fail. Cannot be extended from the end of the zooming groove.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has a lens housing structure capable of shortening the length of a lens barrel with a simple structure without expanding the rotation angle range of a cam ring. The purpose is to provide.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cam ring which rotates or advances and retreats in the optical axis direction, a lens driving cam groove formed in the cam ring, and a lens driving cam groove. In a lens comprising a constrained cam follower member and a movable lens barrel which is constrained by the cam follower member and moves forward and backward in the optical axis direction when the cam ring moves.
The cam ring further branches from the middle of the lens drive cam groove, and extends in a direction different from the lens drive cam groove, and accommodates the cam follower member and allows the movable barrel to retract. And a biasing member that constantly biases the movable lens barrel with respect to the cam ring in a forward direction in which the cam follower does not enter the storage groove.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. 1 to 3 are cross-sectional views showing an upper half of an optical axis of an embodiment of a zoom lens to which the present invention is applied. FIG. 1 shows a state at a wide end (shortest focal length), and FIG. FIG. 3 shows an intermediate focal length state, and FIG.

This zoom lens is an interchangeable lens for a single-lens reflex camera, and includes a first lens unit L1 and a second lens unit L2. The first lens group L1 is held movably in the optical axis direction by a first lens holding lens barrel (moving lens barrel) 11, and the second lens group L2 is held in the optical axis direction by a second lens holding lens barrel. Movably held.

At the rear end of the fixed outer cylinder 31, a bayonet ring 33 mounted on a camera mount is fixed. On the outer periphery of the fixed outer cylinder 31, near the bayonet ring 33,
An aperture ring 35 for setting an aperture value at the time of switching between automatic / manual aperture and manual aperture is rotatably fitted, and a zooming operation ring 37 is rotatably fitted in front of the aperture ring 35. Further, a distance operation ring (focus adjustment ring) 41 is rotatably fitted to the distal end of the fixed outer cylinder 31. In the distance operation ring 41, a thrust pin 42 protruding from an outer peripheral surface in the fixed outer cylinder 31 is slidably fitted into a circumferential guide groove 33 a formed on an inner peripheral surface of the fixed outer cylinder 31, and thereby, light is emitted. It is rotatably guided in a state where it cannot move in the axial direction.

A fixed inner cylinder 43 is provided inside the fixed outer cylinder 31. Outside these, the inner cylinder 31, the fixed inner cylinder 43
Are fixed together by screws 38 with their rear end flanges overlapped. Reference numeral 39 in the drawing denotes a protection ring fixed to the bayonet ring 33 for protecting the connection member with the body, shielding light, and the like.

A cam ring 51 is rotatably fitted to the outer periphery of the fixed inner cylinder 43 so as not to move in the optical axis direction. The cam ring 51 rotates in conjunction with the rotation of the zooming operation ring 37 by an interlock mechanism (not shown).
The cam ring 51 includes a first group cam groove 53 for driving the first lens group L1 and the second lens group L2 in the optical axis direction,
A group cam groove 55 and a storage cam groove 57 that allows the first lens group L1 to retreat are formed (see FIG. 4).

The first lens holding lens barrel 11 holding the first lens unit L1 is a helicoid 1 formed on the inner peripheral surface.
1a meshes with the helicoid 13a formed on the outer periphery of the helicoid ring 13, and the guide portion 11 protrudes from the rear end.
“b” is slidably fitted in a linear guide groove (not shown) formed in the distance operation ring 41 in the optical axis direction. Therefore, when the helicoid ring 13 moves in the optical axis direction with the distance operation ring 41 not rotating, the first lens holding lens barrel 11 moves together. It moves in the optical axis direction relative to the helicoid ring 13.

The helicoid ring 13 is slidably fitted on the outer periphery of the cam ring 51. The helicoid ring 13 includes a shaft 14 protruding inward and a first group roller 15 rotatably supported by the shaft 14. The first group roller 15 is fitted in the first group cam groove 53 of the cam ring 51, and the tip of the shaft 14 protruding from the first group roller 15 is fitted in a straight guide groove 43 a formed in the fixed inner cylinder 43. . Therefore, when the cam ring 51 rotates, the helicoid ring 13 is restrained by the first group cam groove 53 and the linear guide groove 43a , and moves in the optical axis direction in the first group lens holding barrel 11 and the first lens group L1.
Move with.

The second lens group holding lens barrel 21 holding the second lens group L2 is slidably fitted on the inner peripheral surface of the fixed inner cylinder 43. The second group roller 23 is mounted on the outer peripheral surface of the fixed inner cylinder 43 via the pin 22. The second group roller 23 includes a linear guide groove 41 formed in the fixed inner cylinder 43.
a and fits in the second group cam groove 55 of the cam ring 51. Therefore, the second lens group holding lens barrel 21 is
When 1 rotates, it is constrained by the contour of the second group cam groove 55 and moves along the second lens group L2 in the optical axis direction. What
In addition, in FIGS. 1 to 3, reference numeral 23 s denotes a second group lens.
A diaphragm blade of a diaphragm mechanism mounted on the tip of the holding barrel 21
It is.

A spring 61 is provided between the first lens group holding lens barrel 11 and the second lens group holding lens barrel 21 to urge them in directions away from each other. When the first lens holding lens barrel 11 is retracted to the retracted position against the urging force of the spring 61, the outer surface of the distal end of the first lens holding lens barrel 11 and the inner peripheral surface of the distal end of the distance control ring 41 are biased. Further, an engagement pin 11c and an engagement groove 41c are provided as a stop mechanism for preventing the first group lens holding barrel 11 from projecting due to the urging force of the spring 61 (see FIG. 3).

First lens unit L1 and second lens unit L2
Moves during the zooming in the optical axis direction along the contours of the first group cam groove 53 and the second group cam groove 55. The zoom lens according to the present embodiment has a configuration in which the first lens unit L1 is most retracted substantially at an intermediate focal length between the shortest focal length (wide end) and the longest focal length (tele end). Therefore, in the present embodiment, a storage cam groove 57 branched from the intermediate focal length (the last retreat position, the inflection point) and extending further rearward is provided. The first group roller 15 enters the storage cam groove 57 when the lens is stored as described later.

The cam grooves 53 and 55 and the storage cam groove 57 operate as follows. Zooming operation ring 37
Is rotated by the photographer, the cam ring 51
Rotates. Here, when the zoom operation is performed in the telephoto direction from the wide end state in FIG. 1 (when the cam ring 51 rotates in the telephoto direction), the first group roller 15 (the first lens group L1) is moved to the first group cam groove 53. The second group roller 2
3 (second lens group L2) is advanced by being restrained by the second group cam groove 55. Then, the first group roller 15 reaches the switching port 57 a of the first group cam groove 53. Here, since the first lens unit L1 is urged in the forward direction by the spring 61,
The first group roller 15 is pressed against the front surface of the first group cam groove 53 and does not enter the storage cam groove 57 having the switching port 57a on the rear surface of the first group cam groove 53. When the cam ring 51 further rotates in the telephoto direction, the first group roller 15 is advanced by being restrained by the contour of the front surface of the first group cam groove 53. The same applies to the operation when the cam ring 51 rotates in the wide direction.

Next, the storing operation and storing operation of the lens barrel, which are features of the present invention, will be described. When storing, the photographer rotates the zooming operation ring 37 to an intermediate position where the first lens unit holding lens barrel 11 is most retracted.
This intermediate position is such that the first group roller 15 is
And the position facing the switching port 57a of the storage cam groove 57. In this state, when the photographer pushes the first group lens holding barrel 11 against the urging force of the spring 61, the first group roller 15 enters the storage cam groove 57 from the switching port 57a, and the first group lens holding mirror The cylinder 11 retreats along the storage cam groove 57 together with the helicoid ring 13. And the engagement pin 11c
Enter the engagement groove 41b, and the first
The group lens holding barrel 11 is held at the storage position regardless of the biasing force of the spring 61. Since the relative position of the first group lens holding barrel 11 with respect to the helicoid ring 13 is changed by the focus adjustment by rotating the distance operation ring 41, the engagement pin 11c and the engagement groove 41b are provided at any relative position. The total length of the storage cam groove 57 is set so that is engaged.

When projecting the first lens group holding lens barrel 11 from the storage position to the photographable position, the photographer grasps the first lens group holding lens barrel 11 with a finger and pulls it out, or moves the distance operation ring 41 to a short distance. The first group lens holding lens barrel 11 is protruded by rotating in the focusing direction.

Next, a second embodiment will be described with reference to FIG. This embodiment is a modification of the first embodiment, in which the storage lock can be released by operating a button. The engaging pin 45 is formed in a grooved hole 11 having a cross-section provided on the outer peripheral surface near the distal end of the first lens holding lens barrel 11.
d is movably fitted in the diametric direction so as not to come off, and is constantly urged to move by the elastic member 46 in the protruding direction.

An engagement hole 63 is formed at the distal end of the distance control ring 41, and an engagement release pin 64 is inserted into the engagement hole 63. The tip of the engagement release pin 64 is
The engagement operation button 65 is fixed to the protruding portion of the distance operation ring 41 from the hole 63a communicating with the hole 63a, and a flange portion 66 is formed at the rear end portion to prevent the engagement operation button 65 from coming out of the hole 63a. ing. Then, the disengagement operation button 6
An elastic member 67 for urging the disengagement pin 64 to move in the engagement direction is mounted between the distance operation ring 41 and the distance operation ring 41.

The storing operation of the second embodiment is as follows. First, the distance control ring 41 is rotated to a position where the first lens holding lens barrel 11 is most retracted (infinity in-focus position). Then, after rotating the zoom operation ring 37 to the storage position, the first lens holding lens barrel 11 is pushed in. At this time, the first group roller 15 enters the storage cam groove 57 from the switching port 57a.

On the other hand, when the first lens holding lens barrel 11 is pushed toward the storage position, the inclined portion 45
a slides against the edge of the distance operation ring 41 and is pushed in against the urging force of the elastic member 46, and when it reaches the engaging hole 63, it protrudes by the urging force of the elastic member 46 and fits into the engaging hole 63;
The first lens holding lens barrel 11 is locked at the storage position.

When the photographer presses the disengagement operation button 65, the flange portion 66 comes into contact with the engagement pin 45 and is pushed out from the engagement hole 63, so that the first lens holding lens barrel 11 has a spring 61. Projecting to the photographable position by the urging force.

FIG. 6 is a development view of the cam ring for the third embodiment, and FIGS. 7 and 8 show a third embodiment of the click stop mechanism. In this embodiment, a protruding edge 13b is provided at the rear edge of the helicoid ring 13, the helicoid ring 13 is retracted to the storage position on the inner surface of the fixed outer cylinder 31, and the zoom operation ring 37 is rotated to the lock position. sometimes,
A stopper plate 71 for locking the helicoid ring 13 and therefore the first lens group holding lens barrel 11 at the storage position by engaging a stopper portion 71a at one end with the protruding edge portion 13b is provided.

The stopper plate 71 has an axis 73 parallel to the optical axis X.
The stopper 75 is pivotally urged by a spring 75 in a direction to maintain the engagement with the engagement portion 13b at all times, but the other end 71b is normally zoomed. The stopper portion 71a is held at a position where the stopper portion 71a does not engage with the protruding edge portion by slidingly contacting the inner peripheral surface of the operation ring 37.

The lens housing operation of this embodiment is as follows. The operation of operating the zoom operation ring 37 to the intermediate position and then pushing the first group lens holding barrel 11 to the storage position is the same as in the first and second embodiments.

When the zoom operation ring 37 is rotated in the lock direction (wide direction) after the first lens holding lens barrel 11 is pushed into the storage position, the first group roller 15 enters the lock cam groove 58 and the lock cam groove 58 , The end 71b of the stopper plate 71 enters the lock hole 37a on the inner peripheral surface of the zoom operation ring 37. Therefore, the stopper plate 71 rotates in the locking direction, and the locking portion 71a
Engages with the protrusion 13b of the helicoid ring 13 to prevent the helicoid ring 13 from moving forward. That is, the first lens holding lens barrel 11 is locked at the storage position. Note that the lens holding lens barrel 11 is held at the storage position without providing the stopper plate 71, but the stopper plate 71
5 is reduced.

When the zoom operation ring 37 is rotated in the unlocking direction, the end 71b of the stopper plate 71 is
Since it is pushed out from a, the stopper plate 71 rotates in the lock release direction to release the stop of the helicoid ring 13.
When the first group roller 15 comes out of the lock groove 58 and enters the storage cam groove 57, the first group roller 15 can move forward along the storage cam groove 57. Therefore, the first lens group holding lens barrel 11 protrudes due to the urging force of the spring 61.

According to this embodiment, the first lens group holding lens barrel 11 retracted to the storage position can be locked by the stopper plate 71, so that an overload is applied to the lens driving system such as the first lens group 15. Absent. Moreover, since the lock can be easily released by rotating the zoom operation ring 37, the operability is very good.

Although the present invention has been described based on the embodiment applied to the zoom lens, the present invention is not limited to this embodiment. In short, the storage groove may be formed in the cam drive in the middle of the lens driving section, and the lens barrel may be configured to be retractable in the storage groove.

[0031]

As described above, according to the present invention, since the lens housing groove extending in the optical axis direction from the middle of the lens driving section of the cam groove is formed, it is not necessary to increase the rotation angle of the cam ring.
The cam design becomes easy. Also, even when the end of the lens drive section is used for a stopper or signal detection,
It does not affect these functions.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an upper half of an embodiment in which a lens housing structure of the present invention is applied to a two-unit zoom lens in a state where a lens barrel length is the longest along an optical axis.

FIG. 2 is a cross-sectional view showing the upper half of the zoom lens taken along the optical axis in a state where the lens barrel length is the shortest in a zoomable region.

FIG. 3 is a cross-sectional view showing the upper half of the zoom lens taken along the optical axis in a lens storage state in which the lens barrel length is the shortest.

FIG. 4 is a developed plan view showing a cam ring of the zoom lens.

FIG. 5 is a cross-sectional view of a principal part showing a side surface of another embodiment of the storage stopper mechanism of the zoom lens.

FIG. 6 is an expanded plan view showing a cam ring of another embodiment of the lens housing structure.

FIG. 7 is a cross-sectional view showing a main part of a side surface of the stopper mechanism of the embodiment.

FIG. 8 is a cross-sectional view showing a main part on the front side of the stopper mechanism of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 1st group lens holding barrel 11c Engagement pin 13 Helicoid ring 15 1st group roller 21 2nd group lens holding barrel 23 2nd group roller 31 Outside fixed barrel 37 Zoom operation ring 41 Distance adjustment ring 51 Cam ring 57 Storage cam groove 57b Lock groove 71 Stopper plate

Claims (5)

(57) [Claims] A cam ring that rotates or moves forward and backward in the optical axis direction; a lens driving cam groove formed in the cam ring; a cam follower member constrained by the lens driving cam groove; in the lens that includes a moving lens barrel that is bound to said cam follower member to move forward and backward in the optical axis direction when exercising, above Symbol cam ring further branched from the middle of the lens driving cam groove, the lens driving cam Extending in a different direction from the groove,
A storage groove for allowing the cam follower member to enter and allowing the movable lens barrel to retreat, wherein the movable lens barrel is always attached to the cam ring in a forward direction in which the cam follower member does not enter the storage groove. And a biasing member for biasing the lens. 2. The lens housing structure according to claim 1 , wherein said movable barrel is provided in said lens driving groove.
A zoom lens that is most retracted at a focal length between the shortest focal length and the longest focal length that is constrained to move ,
The storage structure of the lens, wherein the storage groove branches backward from the lens drive cam groove and extends rearward at a position where the movable lens barrel is most retracted. 3. A lens storage structure according to claim 1 or 2.
In the structure, between the fixed barrel and the movable barrel,
A lens storage structure comprising locking means for locking the movable lens barrel at the storage position when the cam follower member enters the storage groove and the movable lens barrel retreats to the storage position. 4. A housing for a lens according to claim 1 or 2.
In construction, the said accommodating cam groove from an end of the housing the cam grooves extending in different directions, storage structure of the lens is provided with a locking groove to prevent the projection of the moving lens barrel. 5. The lens storage structure according to claim 4, wherein
The movable barrel is moved from the last retracted position to the camshaft.
The follower member enters the storage groove and the storage position and the
It is formed so that it can be moved manually until it reaches the lock groove
Lens storage structure.