JPH07120651A - Lens position regulating mechanism - Google Patents

Abstract

PURPOSE:To regulate the optical axial position of a lens without rotating the lens by providing a tapered support part having a tapered face tapered toward the optical axis and capable of sliding in the optical axial direction on the holding part of a lens frame holding member. CONSTITUTION:A lens holding means for holding a third lens group L3 has a third lens frame 31 for directly holding the third lens group L3, and a third lens frame holding cylinder 41 for holding the third lens frame 31 holding the third lens group L3. A tapered support part 35 having a Y-shaped front view is protruded on the outer circumferential face of the third lens frame 31. On the other hand, the third lens frame holding cylinder 41 has a taper support part 44 to which the tapered support part 35 is fitted. The optical axial position is regulated by fitting a regulating jig to a pentagon hole, rotating the regulating jig in the direction to move the third lens frame 31, and moving the third lens frame 31 in the optical axial direction without rotating to the third lens frame holding cylinder 41 by the screwing action of a male screw part 62 and a female screw part 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens position adjusting mechanism such as a taking lens of a camera.

[0002]

2. Description of the Related Art Among conventional photographic lenses for cameras, there is a lens holding member provided with a mechanism for adjusting the position of a part of the lenses in the optical axis direction. For example, as shown in FIGS. 6 and 7, there is one in which a lens frame 101 that holds the lens L and a lens frame holding member 121 that holds the lens frame 101 are joined by screwing helicoids 103 and 123. When the position is adjusted, the gear portion 105 formed on the outer periphery of the lens frame 101.
The pinion (not shown) meshed with is rotated to rotate the lens frame 101 with respect to the lens frame holding member 201. The rotation of the lens frame 101 causes the lens frame 101,
Therefore, the lens L is moved back and forth in the optical axis direction while rotating, and the lens position is adjusted. Reference numeral 125 is a guide member which is fitted in a straight guide groove of a lens barrel (not shown) and which guides the lens frame holding member 121 so as to be movable back and forth in the optical axis direction.

Lens frame 101 and lens frame holding member 121
The biasing member 111 is provided between the lens frame 101 and the lens frame holding member 121 in order to prevent looseness between the lens frame 101 and the lens frame 101. The urging member 111 causes the lens frame 10 to move by the elastic bending force of the three claws 113 cut and raised from the annular body.
1 and the lens frame holding member 121 are urged to separate from each other in the optical axis direction.

However, such a configuration in which the lens frame is rotated and adjusted has a problem that the optical axis of the lens and the optical axis of the photographing lens are deviated if the lens frame or the like is decentered.
Further, if some projection or member is provided on the lens frame, there is a problem that a space must be secured so that this portion can pass by rotation.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens position adjusting mechanism capable of adjusting the position of the lens in the optical axis direction without rotating the lens. .

[0006]

SUMMARY OF THE INVENTION The present invention which achieves this object comprises a lens frame for holding a lens and a lens frame holding member for holding the lens frame movably in the optical axis direction. The holding portion is provided with a taper support portion having a taper surface that is tapered toward the optical axis and is slidable in the optical axis direction.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a sectional view showing a lens shutter type camera to which the present invention is applied along the optical axis, showing an upper half of a main portion, and FIG. 2 is an exploded perspective view of an essential portion of a third lens holding member of the camera. Three
Is the cutting line II with the third lens holding member assembled.
FIG. 3 is a cross-sectional view taken along the line I-III. The camera is a zoom lens camera including three lens groups L1, L2, and L3. In FIGS. 1, 2, and 4, the left side is the subject side in the front direction, and the right side is the film side in the rear direction.

An adjusting ring 13 for adjusting the back focus is fixed to the subject side of the body frame 11 as a fixed structure, and a guide ring which moves in the optical axis direction in the body frame 11 and the adjusting ring 13 when adjusting the back focus. 15 is fitted. A cam ring 17 is arranged in the guide ring 15, a first lens barrel 19 is arranged in the cam ring 17, and a rectilinear lens barrel 21 is arranged in the first lens barrel 19.

The guide ring 15 and the cam ring 17 are the guide ring 15
Helicoid 15a formed on the inner peripheral surface of the
Are linked by meshing with a helicoid 17a formed on the outer periphery of the. The cam ring 17 and the first lens barrel 19 are
The helicoid 17b formed on the inner circumference of the cam ring 17 and the first
The lens barrel 19 is linked by meshing with a helicoid 19b formed on the outer periphery of the lens barrel 19. The first lens barrel 19 and the rectilinear lens barrel 21 are fitted with straight guide grooves and ridges (not shown) formed on the inner circumference of the first lens barrel 19 and the outer circumference of the rectilinear lens barrel 21, respectively. It is linked so as to be relatively movable in the optical axis direction without rotating. Cam ring 17 and rectilinear lens barrel 2
The reference numeral 1 and 1 are linked to each other so that they can rotate relative to each other and integrally move in the optical axis direction.

A bent portion 23a at the tip of a guide plate 23 fixed to the end of the rectilinear lens barrel 21 is fitted in a rectilinear guide groove (not shown) formed in the guide ring 15 and extending in the optical axis direction. . Therefore, the rectilinear lens barrel 21 is restricted by the guide plate 23 and the rectilinear guide groove, and is guided so as to be movable in the optical axis direction along the rectilinear guide groove.

A first lens unit L1 is fixed to the tip of the first lens barrel 19. In the straight lens barrel 21, the second
The lens unit L2 is arranged. The second lens unit L2 is fixed to the second lens frame 25, and is helicoidally coupled in a donut-shaped AF / shutter block 27. AF
The shutter block 27 is fixed to a shutter holding frame 29, and rollers (not shown) projecting from a plurality of positions of the shutter holding frame 29 are linearly guided by the linear lens barrel 21 and the first lens barrel 19. It penetrates a groove (not shown) and is fitted in a cam groove (not shown) formed in the cam ring 17. Therefore, when the cam ring 17 rotates, the second lens frame 25 and the second lens group L2 move relative to the rectilinear lens barrel 21 in the optical axis direction.

A third lens unit L3 is arranged in the rectilinear lens barrel 21 behind the second lens unit L2. Third
The lens unit L3 is fitted in the third lens frame 31, and the third lens frame 31 is a third lens frame holding cylinder (lens frame holding member) 4
1 is fitted. Guide portions 42 are provided at a plurality of locations on the outer periphery of the third lens frame holding cylinder 41, and a roller 43 is axially supported by each guide portion 42 in a radial direction orthogonal to the optical axis O. Each guide portion 42 is slidably fitted in a straight guide groove (not shown) formed in the straight lens barrel 21.
Further, the roller pin 43 penetrates through an opening at the bottom of the straight guide groove of the straight lens barrel 21 and is fitted into a cam groove formed in the cam ring 17. Therefore, the third lens frame holding cylinder 41, the third lens frame 31, and the third lens group L3 are connected to the rectilinear lens barrel 2
It is guided along the straight guide groove 1 so as to be movable back and forth in the optical axis direction.

Further, although not shown, a pinion meshes with a spiral gear formed on the outer periphery of the cam ring 17, and this pinion is linked to the drive shaft of the zoom motor via a gear train. When this zoom motor rotates,
The cam ring 17 rotates via a pinion, a spiral gear, etc. for zooming.

This zoom lens having the above-mentioned mechanism,
The following works during zooming. Cam ring 17
When is rotated, the cam ring 17 moves in the optical axis direction while rotating. By rotating the cam ring 17 and moving in the optical axis direction,
The first lens barrel 19 moves in the optical axis direction without rotating. Therefore, the first lens unit L1 is the first lens barrel 1
It moves in the optical axis direction together with 9.

Further, due to the movement of the cam ring 17 in the optical axis direction, the rectilinear lens barrel 21 moves in the optical axis direction without rotating with the cam ring 17. Since the cam ring 17 and the rectilinear lens barrel 21 move relatively in the optical axis direction, the second lens unit L2 and the third lens unit L
3 moves relatively in the optical axis direction by the action of the cam groove of the cam ring 17. Zooming is performed by the relative movement of the first lens unit L1, the second lens unit L2, and the third lens unit L3 relative to each other.

Next, the support structure for the third lens unit L3, which is the essential part of the present invention, will be described. The lens holding means for holding the third lens group L3 includes a third lens frame 31 for directly holding the third lens group L3 and a third lens frame holding for holding the third lens frame 31 holding the third lens group L3. A cylinder 41 is provided. The third lens frame 31 has a cylindrical shape,
The third lens unit L3 is held in the hollow portion. The third lens group L3 mounted on the third lens frame 31 is elastically pressed and fixed to the third lens frame 31 by the annular lens pressing plate 51, and is prevented from falling off. Third lens frame 31
Is fitted in the third lens frame holding cylinder 41 so as to be movable in the optical axis direction.

The third lens frame holding cylinder 41 has three guide portions 42 and rollers 43 as already described. The guide portion 42 is fitted in a straight guide groove formed in the straight lens barrel 21, and the roller 43 penetrates the straight guide groove and is fitted in a cam groove formed in the cam ring 17. That is, the third lens frame holding barrel 41 is guided so as to be movable back and forth in the optical axis direction along the straight guide groove of the straight lens barrel 21, and the rotation of the cam ring 17 causes the cam action of the cam groove and the roller 43 to cause the optical axis. Move back and forth in the direction.

The lens pressing plate 51 is a member having elasticity,
For example, it is formed of metal or synthetic resin.
The lens pressing plate 51 includes a hollow disk-shaped annular main body 52, and a tongue piece 54 that extends by bending in the optical axis direction from a plurality of locations on the outer peripheral edge portion of the annular main body 52, and engages with the tongue piece 54 at substantially the center thereof. It has a hole 55. The lens pressing plate 51 is fixed to the third lens frame 31 by engaging the engaging holes 55 with the engaging claws 33 projecting from the outer peripheral surface of the third lens frame 31, and fixing the third lens group L3. It is held with respect to the third lens frame 31.

On the outer peripheral surface of the third lens frame 31, a taper support portion 35 having a front Y shape is provided in a protruding manner. The taper support portion 35 has a pair of guide walls 36 extending parallel to the optical axis O. A taper surface 37 is formed on the outer surface of each guide wall 36 so as to approach each other toward the optical axis O.
Between both the tapered surfaces 37, there is a split groove-shaped female screw portion 38 extending in the optical axis direction.

On the other hand, the third lens frame holding cylinder 41 is formed with a taper support portion 44 into which the taper support portion 35 is fitted. The taper support portion 44 includes a pair of taper guide grooves 45 for accommodating the guide wall 36 so as to be movable in the optical axis direction, and a pair of bridges 46 a that straddle the pair of taper guide grooves 45.
46b is provided. Each of the pair of taper guide grooves 45 is provided with a taper surface 47 approaching toward the optical axis. This tapered surface 47 is the tapered surface 3 of the tapered support portion 35.
It comes into contact with 7 slidably. Also, a pair of bridges 46
a and 46b are separated from each other in the optical axis direction, and bridges 46a and 4b
On the optical axis side surface of 6b, a semi-cylindrical small-diameter split bearing 48a and a large-diameter split bearing 4 extending parallel to the optical axis O about the same axis.
8b is formed. The split bearings 48a and 48b are formed such that their axial centers substantially coincide with the axial center of the female screw portion 38 in a state of being fitted to the third lens frame holding cylinder 41.

A screw member 61 is mounted between the bridges 46a and 46b from the optical axis side. The screw member 61 includes a male screw portion 62, and a small diameter shaft 63 and a large diameter shaft 64 extending from both ends of the male screw portion 62, and the shafts 63 and 64 fit into the split bearings 48a and 48b, respectively. The female threaded portion 38 and the male threaded portion 62 are formed according to a standard in which they are screwed together.

The third lens frame 31 is fitted with the screw member 61 attached to the third lens frame holding cylinder 41. At the time of this fitting, the screw member 61 is rotated by a rotating tool fitted in a hexagonal hole 65 formed in the end surface of the large diameter shaft 64. By the rotation of the screw member 61, the male screw portion 62 meshes with the female screw portion 38, the third lens frame 31 moves in the optical axis direction, and is fitted into the third lens frame holding cylinder 41. In this fitted state, the third lens frame 31 and the third lens frame holding cylinder 41 hold the outer peripheral surface of the third lens frame 31 and the third lens frame holding state with the tapered surface 37 and the tapered surface 47 in contact with each other. A small gap is left between the inner peripheral surface of the cylinder 41.

The position adjustment of the third lens unit L3 in the optical axis direction is performed by
It is performed as follows. The adjustment jig is fitted in the hexagonal hole 65, and the adjustment jig is rotated in the direction in which the third lens frame 31 is to be moved. Then, the third lens frame 31 has the male screw portion 6
Due to the screwing action of 2 and the female screw portion 38, the third lens frame holding cylinder 41 moves in the optical axis direction without rotating. Here, since the male screw portion 62 and the female screw portion 38 are formed so as to overlap in the radial direction at the time of fitting, the female screw portion 38 elastically moves toward the optical axis by the male screw portion 62 at the time of fitting. Be energized. Therefore, the taper support portion 35 is
It is formed of a member having elasticity. In the rectilinear movement of the third lens frame 31, the taper support portion 35 and the taper guide groove 45 slide while maintaining a contact state due to the radial urging force of the male screw portion 62 and the elastic stress of the taper support portion 35. Therefore, there is no play between the third lens frame 31 and the third lens frame holding cylinder 41.

The second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Members having the same functions or actions as those of the embodiment shown in FIGS. 1 to 3 are designated by the same reference numerals and the description thereof will be omitted.

The taper support portion 71 projectingly provided on the outer peripheral surface of the third lens frame 31 is provided with a pair of taper surfaces 72 which taper narrowly toward the optical axis O on both side surfaces of the root portion. A screw hole 73 extending parallel to the optical axis O is formed in the center of the front surface of 71. The tapered surface 72 is orthogonal to the orthogonal surface of the optical axis O.

A pair of engagement grooves 7 extending in the lateral direction (parallel to the surface orthogonal to the optical axis) are provided in front of and behind the outer surface of the taper support portion 71.
4 are formed at predetermined intervals. A biasing leaf spring 75 is inserted between the pair of engagement grooves 74. Energizing leaf spring 75
Has a cut-and-raised piece 76 at approximately the center. The cut-and-raised piece 76 extends in the optical axis direction and in a direction away from the optical axis O, and is bent by its own elastic force.

On the other hand, the third lens frame holding cylinder 41 is provided with a taper support portion 81 having a fitting hole 82 into which the taper support portion 71 is fitted. The fitting hole 82 has an inner edge portion that forms an opening on the optical axis side, and the tapered surface 7 of the tapered support portion 71.
The tapered surface 83 that is in sliding contact with the tapered support portion 7 is formed.
A wall 84 is formed on the side opposite to the insertion port of No. 1, and a hole 85 is formed in this wall. An adjusting screw 91 is inserted into the hole 85 from the rear side, and the adjusting screw 91 is inserted into the hole 8
5 is locked so as to be rotatable and not to move in the optical axis direction.

The third lens frame 31 is fitted into the third lens frame holding cylinder 41 from the front side. In this fitted state,
The taper support portion 71 is fitted in the fitting hole 82. In this state, the taper support portion 71 is elastically biased toward the optical axis O by the elastic restoring force of the cut-and-raised piece 76 that comes into pressure contact with the upper wall of the fitting hole 82. Therefore, the third lens frame 31
The tapered surface 72 is elastically pressed against the tapered surface 83. Further, the adjusting screw 91 is screwed into the screw hole 73. That is, the rotation of the adjusting screw 91 moves the third lens frame 31 in the optical axis direction, and the position of the third lens group L3 in the optical axis direction is adjusted. Further, since the taper surface 72 tapering toward the optical axis is pressed by the taper surface 83, the third lens L3 is centered by this taper action.

Thus, in this embodiment, the third lens frame 3
The taper surface 3 of the taper support members 35, 44 or 71, 81 provided with the first lens frame holding cylinder 41 and the third lens frame holding cylinder 41 at one place.
It can be supported movably in the optical axis direction by sliding contact of 7, 47 or the tapered surfaces 72, 83. According to this configuration, since the biasing member that biases the third lens frame 31 and the third lens frame holding cylinder 41 relatively in the radial separation direction can be provided in the radial direction, the space in the optical axis direction can be provided. Can save
Further, in the lens position adjusting mechanism of the present embodiment, since the third lens frame 31 does not rotate about the optical axis, a space for accommodating the taper support portion is sufficient, and the lens barrel has irregularities. Also, since it is only necessary to make a space for accommodating the taper support portion or to dispose the taper support portion in the space portion, it is possible to easily configure.

Further, in the illustrated embodiment, the example in which the present invention is applied to the lens holding means of the third lens unit L3 that moves by zooming has been described, but the present invention is not limited to this, and is applied to the lens holding means of the fixed lens. It can also be applied.

[0031]

As is apparent from the above description, the present invention is
The lens frame and the holding part of the lens frame holding member are provided with a taper portion that has a taper surface that is tapered toward the optical axis and is slidable in the optical axis direction, and can be moved in the optical axis direction by sliding contact with the tapered surface. Since the urging member for urging the lens frame and the lens frame holding cylinder can be provided in the radial direction, the space in the optical axis direction can be saved. Also,
In the present invention, since the lens frame does not rotate, it suffices if there is a space only in the tapered support portion, and even if the lens barrel has irregularities,
Since it is sufficient to make a space only for the taper support portion or to locate the taper support portion in the space portion, it is possible to easily configure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of an upper half of a lens shutter type camera to which the present invention is applied, which is longitudinally cut along an optical axis.

FIG. 2 is an exploded perspective view showing a main part of a lens position adjusting mechanism in the embodiment.

3 is a cross-sectional view showing a main part by cutting along a cutting line III-III in FIG.

FIG. 4 is an exploded perspective view showing a main part of a second embodiment of the present invention.

5 is a cross-sectional view showing a main part by cutting along a cutting line VV in FIG.

FIG. 6 is a sectional view showing a main part of a conventional lens position adjusting mechanism.

FIG. 7 is an exploded perspective view showing a main part of the conventional example.

[Explanation of symbols]

 11 body frame 13 adjustment ring 15 guide ring 17 cam ring 19 first lens barrel 21 straight lens barrel 25 second lens frame 27 AF / shutter block 31 third lens frame 33 engaging claw 35 taper support portion 37 taper surface 38 female screw Part 41 Third lens frame holding cylinder 44 Tapered support part 47 Tapered support surface 51 Lens pressing plate 54 Tongue piece 55 Engagement hole 56 Friction part 61 Screw member 71 Tapered support part 72 Tapered surface 81 Tapered support part 83 Tapered surface 91 Adjustment screw

Claims (5)

[Claims] 1. A lens frame for holding a lens, and a lens frame holding member for holding the lens frame movably in the optical axis direction, wherein the lens frame and the holding portion of the lens frame holding member face the optical axis. The lens position adjusting mechanism is characterized in that a taper supporting portion having a tapered surface that is slidable along the optical axis is provided. 2. The lens frame according to claim 1, wherein the lens frame is formed so as to be freely inserted into and removed from the lens frame holding member, and a female screw portion extending parallel to the optical axis is formed in the vicinity of the one tapered portion. A lens position adjusting mechanism in which a screw member that is rotatably supported by the lens frame holding member is screwed into the portion. 3. The female screw portion according to claim 2, wherein the female screw portion is formed in a portion between the pair of tapered surfaces, and is formed in a groove of a half circumference or less extending in the optical axis direction. A lens position adjusting mechanism, which is pressed and held in the direction of the internal thread by a pair of split bearings formed on the lens frame holding member. 4. The female threaded portion according to claim 2, wherein the female threaded portion is a threaded hole formed through the intermediate surface of the pair of tapered surfaces and parallel to the optical axis, and the threaded member is attached to the lens frame holding member. A lens position adjusting mechanism that is rotatably supported and screwed into the screw hole. 5. The elastic urging member for urging the lens frame and the lens frame holding member in a direction for holding the contact between the tapered surfaces is provided between the tapered support portions. Lens position adjustment mechanism.