JP4821221B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel used for camera video, for example.

  FIG. 3 is a partial cross-sectional view of a lens barrel according to a conventional example. The optical lens group 21 is held by a lens holding frame 22, and the lens holding frame 22 is fixed in a sliding frame 23. A fixed frame 24 and a cam cylinder 25 are fitted on the outer peripheral side of the sliding frame 23. A rectilinear groove 26 is formed in the fixed frame 24, and a cam groove 27 is formed in the cam cylinder 25. A cam pin 28 is erected on the sliding frame 23, and a roller 29 fitted to the outer periphery of the cam pin 28 is engaged with the rectilinear groove 26 and the cam groove 27.

Accordingly, when the sliding frame 23 rotates the cam cylinder 25, the cam pin 28 (roller 29) cooperates with the rectilinear groove 26 of the fixed cylinder 24 and the cam groove 27 of the cam cylinder 25 along the optical axis. It can move back and forth. A washer 30 is interposed between the lens holding frame 22 and the sliding frame 23. The other optical lens groups are omitted because they are irrelevant.
Japanese Patent Laid-Open No. 10-142471

  Normally, when manufacturing an interchangeable lens for a camera, flange back adjustment is performed. For example, in the case of a telephoto lens, adjustment may be made by slightly moving a lens in the focus group. In the case of FIG. 3, after detecting an error between the focusing position of the infinitely distant image in the combination and the film surface position at a predetermined distance from the mount reference surface, fine adjustment is performed so that the focus surface comes to the specified position at that position. . Conventionally, as shown in FIG. 3, adjustment is often performed using a selective washer 30.

  However, when this method is adopted, the washer 30 is built in the lens barrel in advance, so that it is necessary to disassemble the lens barrel once assembled to a position where the lens to be adjusted can be removed, and to assemble again. Inefficient. In addition, when the expected optical performance value is not satisfied due to various manufacturing errors, etc., the same problem occurs when performing tilt alignment that corrects the performance by tilting a specific lens slightly. is there.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a lens barrel that can perform the adjustment efficiently even when a predetermined adjustment is necessary.

In order to achieve the above object, in the lens barrel according to the present invention, a fixed frame and a cam barrel are fitted on the outer periphery of a sliding frame holding an optical lens group, and the cam barrel rotates to In a lens barrel that moves the sliding frame in the front-rear direction along the optical axis with respect to the fixed frame,
The sliding frame is divided in the front-rear direction into two sliding part frames, one of which holds the optical lens group,
The two sliding part frames are biased in a direction away from each other by a biasing means,
I said to the two sliding parts frame, respectively, mosquito Mupin is Yes erected,
At least one of the cam pins is externally fitted with a first roller that engages with the rectilinear groove of the fixed cylinder and a second roller that engages with the cam groove of the cam cylinder,
The relative position of the two sliding partial frames can be adjusted by changing the second roller to a roller having a different diameter .
In addition, a lens barrel according to the present invention is provided on the inner peripheral side of a fixed frame having a rectilinear groove, and is provided with a sense in the optical axis direction from the first portion that holds the optical lens group. A sliding frame having a second portion;
Biasing means for biasing the first part and the second part in a direction away from each other;
A cam cylinder having a cam groove and provided on the outer peripheral side of the fixed frame;
A first cam pin that is erected on the first portion and is disposed in the rectilinear groove of the fixed frame and the cam groove of the cam cylinder;
A second cam pin that is erected on the second portion and is disposed in the rectilinear groove of the fixed frame and the cam groove of the cam cylinder;
A first roller portion provided on an outer periphery of the first cam pin and engaged with the rectilinear groove;
A second roller portion that is provided on an outer periphery of the first cam pin and that is separate from the first roller portion that engages with the cam groove;
The relative position of the first part and the second part can be adjusted by changing the second roller part to a roller having a different diameter .
In addition, a camera according to the present invention includes the lens barrel.
The video according to the present invention is characterized by comprising the lens barrel.

  According to the present invention, even when a predetermined adjustment is necessary, the adjustment can be performed efficiently.

  Hereinafter, a lens barrel according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view of a lens barrel according to an embodiment of the present invention. FIG. 2 is a development view centering on the cam cylinder for explaining the relationship between the cam pin, the cam groove, and the rectilinear groove shown in FIG.

  The optical lens group 1 is held by a lens holding frame 2, and the lens holding frame 2 is fixed in a sliding frame 3. A fixed frame 4 and a cam cylinder 5 are fitted on the outer peripheral side of the sliding frame 3. A rectilinear groove 6 is formed in the fixed frame 4, and a cam groove 7 is formed in the cam cylinder 5.

  In the present embodiment, the sliding frame 3 is divided into a front sliding part frame 3a to which the lens holding frame 2 is fixed and a rear sliding part frame 3b. The front sliding part frame 3 a and the rear sliding part frame 3 b are biased by the spring 10 in a direction away from each other. The spring 10 is a wave washer or the like, but may be another biasing member as long as it can bias the front sliding part frame 3a and the rear sliding part frame 3b.

  A front cam pin 8a and a rear cam pin 8b are erected on the front sliding part frame 3a and the rear sliding part frame 3b, respectively. A front roller 11 and a rear roller 12 that are engaged with the groove 6 and the cam groove 7 of the cam cylinder 5 are externally fitted.

  Accordingly, when the sliding frame 3 rotates the cam cylinder 5, the cam pins 8 a and 8 b (rollers 11 and 12) are moved in the straight groove 6 of the fixed cylinder 4 and the cam groove of the cam cylinder 25 as shown in FIG. 2. 7 can be moved in the front-rear direction along the optical axis together with the optical lens group 1 and the lens holding frame 2. Other optical lens groups are omitted because they are irrelevant.

  Here, the roller 11 on the front side includes a roller 11a that engages with the cam groove 7 and a roller 11b that engages with the rectilinear groove 6, and each is provided separately. Moreover, the diameter of the roller 11a can be adjusted by replacement or the like.

  In other cases such as flange back adjustment and tilt alignment described later, a plurality of sets (for example, two to three sets) of cam pins 8a and 8b and rollers 11a, 11b, and 12 are provided in the circumferential direction around the optical axis. However, only one set is shown for convenience of explanation.

  Next, the procedure for adjusting the flange back with this configuration will be described. In the situation shown in FIG. 2, the lens is placed at the infinity position. In this embodiment, the roller 11a that is externally fitted to the cam pin 8a and engages with the cam groove 7 can be replaced as described above.

  When it is desired to move the optical lens group 1 forward by a small amount (left side in FIG. 1), the roller 11a is changed to a roller whose diameter is smaller than a necessary amount. As a result, the front sliding part frame 3 a is biased by the spring 10 and moves forward together with the lens holding frame 2 and the optical lens group 1. Thus, the position of the optical lens group 1 can be changed while the structural position remains unchanged.

  When it is desired to change the position of the optical lens group 1 to the rear (right side in FIG. 1), the roller 11a is changed to a roller whose diameter is larger than the required amount. In this case, the spring 10 is pushed in the contracting direction, and the front sliding part frame 3 a moves backward together with the lens holding frame 2 and the optical lens group 1.

  With the above method, the flange back adjustment can be performed only by changing the diameter of the roller 11a in a state where the optical lens group 1 is assembled. Since this configuration can be adjusted from the side (external) of the lens barrel, it is possible to adjust the flange back even in a state close to the finished product without disassembling the lens barrel as in the past. As a result, the workability of this adjustment can be made extremely good, and the adjustment can be performed efficiently.

  Also, for example, in the case of a photographic lens, if the expected optical performance value is not satisfied due to various manufacturing errors, a technique called tilt alignment is performed to correct the performance by tilting a specific lens slightly. There is a case.

  When this embodiment is used, for example, by changing the roller 11a to a different diameter for each cam pin 8a, the front sliding portion frame 3a is inclined together with the optical lens group 1 and the holding frame 2. be able to. This can also be adjusted from the side of the lens barrel in the assembled state, so that it can be adjusted from the outside without being disassembled.

  Further, for example, even if a method of integrating the lens holding frame 2 and the front sliding part frame 3a is used, the present embodiment can be used and the cost can be reduced.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

It is a fragmentary sectional view of the lens barrel which concerns on embodiment of this invention. FIG. 2 is a development view centering on a cam cylinder for explaining the relationship between the cam pin, the cam groove and the rectilinear groove shown in FIG. 1. It is a fragmentary sectional view of the lens barrel concerning a conventional example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical lens group, 2 ... Lens holding frame, 3 ... Sliding frame, 3a ... Front side sliding part frame, 3b ... Rear side sliding part frame, 4 ... Fixed frame, 5 ... Cam cylinder, 6 ... Straight groove, 7: Cam groove, 8a, 8b ... Cam pin, 11a, 11b ... Roller

Claims (8)

A fixed frame and a cam cylinder are fitted on the outer periphery of the slide frame holding the optical lens group, and the slide frame is moved back and forth along the optical axis with respect to the fixed frame by the rotation of the cam cylinder. In a lens barrel that moves in the direction,
The sliding frame is divided in the front-rear direction into two sliding part frames, one of which holds the optical lens group,
The two sliding part frames are biased in a direction away from each other by a biasing means,
I said to the two sliding parts frame, respectively, mosquito Mupin is Yes erected,
At least one of the cam pins is externally fitted with a first roller that engages with the rectilinear groove of the fixed cylinder and a second roller that engages with the cam groove of the cam cylinder,
The lens barrel according to claim 1, wherein the relative position of the two sliding part frames can be adjusted by changing the second roller to a roller having a different diameter . The lens barrel according to claim 1,
The lens barrel according to claim 1, wherein a plurality of the at least one cam pin and the second roller are provided in a circumferential direction. A sliding frame having a first portion that is provided on the inner peripheral side of the fixed frame having a rectilinear groove and that holds the optical lens group, and a second portion that is spaced from the first portion in the optical axis direction; ,
Biasing means for biasing the first part and the second part in a direction away from each other;
A cam cylinder having a cam groove and provided on the outer peripheral side of the fixed frame;
A first cam pin that is erected on the first portion and is disposed in the rectilinear groove of the fixed frame and the cam groove of the cam cylinder;
A second cam pin that is erected on the second portion and is disposed in the rectilinear groove of the fixed frame and the cam groove of the cam cylinder;
A first roller portion provided on an outer periphery of the first cam pin and engaged with the rectilinear groove;
A second roller portion that is provided on an outer periphery of the first cam pin and that is separate from the first roller portion that engages with the cam groove;
A lens barrel , wherein the relative position between the first part and the second part can be adjusted by changing the second roller part to a roller having a different diameter . In the lens barrel according to claim 3,
The lens barrel according to claim 1, wherein the second roller portion is provided so as to be replaceable from an outer peripheral side of the cam barrel. In the lens barrel according to claim 3 or 4,
A plurality of the first cam pins are provided in the circumferential direction around the optical axis,
The second roller portion is provided on the outer periphery of the first cam pin,
The lens barrel characterized in that the second roller portion can be changed to a roller having a different diameter . In the lens barrel according to any one of claims 3 to 5,
A lens barrel characterized in that, on the outer periphery of the second cam pin, a roller portion that engages with the rectilinear groove and a roller portion that engages with the cam groove are integrally formed. A camera comprising the lens barrel according to any one of claims 1 to 6. A video comprising the lens barrel according to any one of claims 1 to 6.

Images