JP2008026892A - Lens position adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provides a lens position adjusting device which makes it possible to finely and continuously adjust the position of a lens group in an optical axis direction relative to the rotation position of a manual rotating ring. <P>SOLUTION: A lens position adjusting device of a lens barrel includes a stationary ring 5, and a manual rotating ring 4 which is screw-engaged with the stationary ring to be manually rotatable about an optical axis to move a movable lens group L2 in the optical axis direction, wherein the manual rotating ring 4 includes an operating ring member 41; and a sub-ring member 42 which is screwed into the stationary ring 5 by screw grooves 5a, 42a, wherein the operating ring member 41 and the sub-ring member 42 are constituted adjustably in a relative rotation position by an arcuate groove 412 and a screw 43. By position adjusting the adjusting screw 43 within the arcuate groove 412, the position in the optical axis direction of the lens L2 relative to the rotation position of the manual rotating ring 4 can be continuously adjusted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens position adjusting device for a camera, and in particular, in a lens barrel configured to rotate an operating ring provided in a lens barrel to move the lens in an optical axis direction, The present invention relates to a lens position adjusting device that can adjust the position in the axial direction.

  The lens of the camera is provided with a lens barrel and is equipped with a focus operation ring and zoom operation ring for setting focus (focal position) and zoom (focal length), and the photographer manually operates these operation rings. Is rotated to change the position of the lens in the lens barrel in the optical axis direction to set the focus and zoom. Various mechanisms have been proposed for rotating the operating ring to change the optical axis position of the lens, and one of them is to rotate the cam ring in the lens barrel by rotating the operating ring. In addition, a cam roller that engages with a cam groove provided in the cam ring is integrally provided on the lens frame that supports the lens, and the amount of rotation of the cam ring is set to the amount of movement of the cam roller, that is, the lens in the optical axis direction. There is a configuration to convert.

In such a configuration, adjustment for correctly aligning the rotational position of the operation ring and the position of the lens in the optical axis direction is necessary. For example, the focus adjustment is performed such that when the focus operation ring is set to a distance scale provided on the lens barrel, the lens is moved to a position in the optical axis direction corresponding to the distance. A method for adjusting the relative distance in the optical axis direction between the focus operation ring and the focus cam ring as a method for performing focus adjustment for associating the rotation position of the focus operation ring with the position in the optical axis direction of the lens. There is. That is, if the position of the focus cam ring in the optical axis direction with respect to the focus operation ring is changed, the position of the focus cam ring in the optical axis direction is different even when the focus operation ring is rotated to the same position, and the lens position is changed. Can be changed. In order to perform this adjustment, conventionally, an adjustment shim having a required thickness in the direction of the optical axis is interposed at a portion connecting the focus operation ring and the focus cam ring, and the number of adjustment shims is changed. The relative position between the focus operation ring and the focus cam ring is changed. For example, Patent Document 1 discloses, as an explanation of the prior art, that there is a method of adding an adjustment washer that works equivalent to an adjustment shim in the lens system as one of the lens focus adjustment methods. .
JP 2002-62466 A

  In the technique of adjusting the lens position by adjusting the optical axis direction between members using such an adjustment shim, the adjustment shim has a preset thickness, and therefore the adjustable focus amount is the thickness of the adjustment shim. In the case where a plurality of adjustment shims are used, the focus amount is limited to the number of the adjustment shims. Further, when the adjustment shims having different thicknesses are used, it is possible to change the amount of the numerical value that can be adjusted, but it cannot be solved that the numerical value that can be adjusted is a stepwise numerical value. In addition, there is a limit to reducing the thickness of the adjustment shim, and there is a limit to increasing the accuracy of the thickness dimension, so it is difficult to set the adjustment amount finely. Therefore, conventionally, there is a problem that it is extremely difficult to finely and continuously adjust the position adjustment of the lens in the focus adjustment and the zoom adjustment and perform an adjustment without error.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens position adjusting device that can finely and continuously adjust the position in the optical axis direction of a lens with respect to the rotational position of an operating ring.

  The present invention provides a lens barrel that includes an operation ring that is supported by a fixed ring with a screw structure and is rotated around an optical axis, and a lens that is moved in the optical axis direction following the rotation of the operation ring. The operation ring is composed of an operation ring part that is rotated and an auxiliary ring part that is screwed to the fixed ring, and the operation ring part and the auxiliary ring part are configured such that the relative rotation position can be adjusted. It is characterized by.

  The present invention also includes a cam ring that is rotated integrally with the operation ring and moved in the optical axis direction, and the lens is rotated in the optical axis direction by cam means provided on the cam ring. The optical axis direction relative position adjusting means for adjusting the relative position of the operation ring and the cam ring in the optical axis direction is provided. The optical axis direction relative position adjusting means is configured by an adjustment shim interposed between the operating ring and the cam ring for adjusting the dimension in the optical axis direction of both.

  In the present invention, it is preferable that a circular arc groove in the circumferential direction is formed in one of the operation ring portion and the auxiliary ring portion, and the other is configured such that the relative rotation position can be changed along the circular arc groove. An adjustment screw for connecting the operation ring portion and the auxiliary ring portion in the arc groove is provided, and the relative rotation position is adjusted by changing the position of the adjustment screw in the arc groove. The arc length of the arc groove is such that the distance moved in the optical axis direction when the auxiliary ring portion is rotated by the angle of the arc length is equal to or greater than the thickness dimension of one adjustment shim.

  According to the present invention, since the relative rotation position of the operation ring portion and the auxiliary ring portion of the operation ring can be continuously adjusted, the optical ring direction of the lens with respect to the rotation position of the operation ring is made to follow this. The position can be adjusted continuously. Further, since the relative position of the operation ring and the cam ring in the optical axis direction can be adjusted by the adjustment shim, the optical axis direction of the lens can be adjusted over a long distance range. Further, the operation ring portion and the auxiliary ring portion can be adjusted in relative rotation positions by an arc groove provided on one side and an adjusting screw disposed inside the operation ring portion, and the arc length of the arc groove can be adjusted by the adjustment shim. By setting the length corresponding to the thickness dimension of one sheet, the optical axis direction of the lens can be continuously adjusted over a length range including at least the thickness dimension of the adjustment shim. Therefore, the position adjustment over a very long range is possible by using it together with the adjustment shim.

  Next, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a lens barrel in which the present invention is applied to a focus mechanism, and FIG. 2 is a schematic exploded perspective view of a part thereof. A fixed lens L1 is fixed to the inner front end of the fixed ring 1 in the lens barrel. A lens support frame 2 that is movable along the optical axis direction is inserted at an inner peripheral position of the fixed ring 1, and a movable lens L <b> 2 is supported by the lens support frame 2. The movable lens L2 is for performing focus adjustment in the lens barrel when the movable lens L2 is moved in the optical axis direction. In the first embodiment, the fixed lens L1 and the movable lens L2 are each configured as a lens group, but may be configured by one lens each. A cylindrical focus cam ring 3 is fitted to the outer peripheral position of the fixed ring 1 and is integrally connected to a focus operation ring 4 disposed on the outer periphery of the lens barrel at the front end thereof. A predetermined cam groove 31 is formed in the focus cam ring 3, and is a linear groove in the optical axis direction that is erected on the lens support frame 2, protrudes in the outer diameter direction, and opens in the fixed ring 1. A cam roller 21 is inserted through 11 in the radial direction. Thus, when the focus cam ring 3 is rotated around the optical axis Ax, the lens support frame 2, that is, the movable lens L2 is moved in the optical axis direction by the cam operation of the cam groove 31 and the cam roller 21, and the lens mirror Focus adjustment in the cylinder becomes possible.

  The focus operation ring 4 is screwed and supported by an outer peripheral fixed ring 5 provided on the outermost periphery of the lens barrel. That is, the focus operation ring 4 includes an operation ring portion 41 that is manually rotated by a photographer, and a cylindrical auxiliary ring portion 42 that is connected to the rear side of the operation ring portion 41 in the optical axis direction. The operation ring portion 41 is disposed at a position substantially the same diameter as the outer peripheral fixed ring 5, but the auxiliary ring portion 42 is formed to have a smaller diameter than the outer peripheral fixed ring 5, It is arranged at the circumferential position. The screw groove 5 a provided on the inner peripheral surface of the outer peripheral fixed ring 5 and the screw groove 42 a provided on the outer peripheral surface of the auxiliary ring portion 42 are screwed together. Further, the operation ring portion 41 and the auxiliary ring portion 42 are connected to each other by adjusting screws 43 at three locations in the circumferential direction, as shown in a front view of the operation ring portion 41 seen from the optical axis direction in FIG. Yes. That is, an annular groove 411 centered on the optical axis is formed on the rear surface of the operation ring portion 41 in the optical axis direction, and the concave surface 411 is fitted on the front surface of the auxiliary ring portion 42 in the optical axis direction. An annular flange portion 421 is provided, and the operation ring portion 41 and the auxiliary ring portion 42 are configured to be relatively rotatable about the optical axis Ax by sliding connection between the concave groove 411 and the flange portion 421. ing. Further, arc grooves 412 having a predetermined arc length are respectively penetrated in the plate thickness direction (optical axis direction) at three locations in the circumferential direction of the operation ring portion 41 facing the concave grooves 411 as will be described in detail later. The three adjustment screws 43 inserted through the arc grooves 412 from the front to the rear in the optical axis direction are screwed into the flange portion 421 of the auxiliary ring portion 42, and the three adjustments are made. The operation ring portion 41 and the auxiliary ring portion 42 are integrally connected by sandwiching a part of the region where the arc groove 412 is formed with the screw 43 in the optical axis direction. Therefore, in this connection structure, when the three adjustment screws 43 are loosened, the adjustment screws 43 can be moved relative to each other in the circumferential direction within each arc groove 412. It is possible to rotate the ring portion 41 with respect to the auxiliary ring portion 42 and adjust the relative rotation positional relationship between them.

  In the focus structure including the focus operation ring 4, when the focus operation ring 4 is rotated around the optical axis in the operation ring part 41, the auxiliary ring part 42 connected to the adjustment ring 43 is also rotated integrally. The auxiliary ring portion 42 and the operation ring portion 41, that is, the focus operation ring 4 are slightly moved in the optical axis direction simultaneously with the rotation by screwing of the screw grooves 5a and 42a of the outer peripheral fixed ring 5 and the auxiliary ring portion 42. As described above, the focus cam ring 3 is also rotated by the rotation of the focus operation ring 4 to move the movable lens L2 in the optical axis direction. However, the focus operation ring 4 is moved in the optical axis direction simultaneously with the rotation. In order to move, in the focus cam ring 3, the shape of the cam groove 31 is designed so that the movable lens L2 is moved to a desired optical axis position in consideration of the movement in the optical axis direction.

  Here, the focus cam ring 3 is positioned in the optical axis direction with respect to the inner flange portion 413 provided at the front end portion of the operation ring portion 41 of the focus operation ring 4 at the outer flange portion 32 provided at the front end portion in the optical axis direction. They are in contact with each other and are integrally connected by connecting screws not shown in the drawing. At this time, an annular adjustment shim 6 having a required thickness is interposed between the outer flange portion 32 of the focus cam ring 3 and the inner flange portion 413 of the focus operation ring (operation ring portion) 4, thereby focusing. The relative distance in the optical axis direction between the cam ring 3 and the focus operation ring 4 can be separated by the thickness of the adjustment shim 6. Thereby, when the focus operation ring 4 is rotated and the position in the optical axis direction with respect to the outer peripheral fixed ring 5 is changed and adjusted, the position in the optical axis direction of the focus cam ring 3 that moves in the optical axis direction following this is adjusted. Can be changed by the thickness of the adjustment shim 6, and further, the position of the lens support frame 2 that performs focus adjustment, that is, the position of the movable lens L2 in the optical axis direction can be adjusted. It should be noted that a plurality of adjustment shims 6 having the same thickness are prepared, and an adjustment shim having substantially different thicknesses can be configured by selecting the number of adjustment shims 6 to be interposed. Then, a plurality of such adjustment shims 6 are used.

  According to the configuration of the first embodiment described above, when the photographer rotates the focus operation ring 4, the operation ring portion 41 is rotated, and the auxiliary ring portion 42 connected thereto is integrally rotated. . Since the auxiliary ring portion 42 is screwed to the outer peripheral fixed ring 5 by the screw grooves 42a and 5a, the auxiliary ring portion 42 rotates with the pitch of the screw grooves 5a and 42a as shown in the schematic view of FIG. According to the dimension Lp, it is moved in the optical axis direction by a distance corresponding to the rotation angle. Thereby, the operation ring portion 41, that is, the focus operation ring 4 is also moved in the optical axis direction. The focus cam ring 3 is also integrally rotated in the direction around the optical axis by the rotation of the operation ring portion 41 in the direction around the optical axis and the movement in the optical axis direction, and is simultaneously moved in the optical axis direction. The cam roller 21 engaged with the cam groove 31 is moved in the optical axis direction by the movement of the focus cam ring 3 around the optical axis and in the optical axis direction, and the lens support frame 2, that is, the movable lens L2 is moved in the optical axis direction. As a result, a predetermined position in the optical axis direction corresponding to the rotation position of the focus operation ring 4 is set.

Here, in the case where the optical axis position of the movable lens L2 is not correctly adjusted with respect to the rotation position of the focus operation ring 4, the focus operation ring 4 is actually adjusted to the distance scale provided on the outer peripheral fixed ring 5. An error occurs in the focus position. Therefore, as the focus adjustment, an adjustment operation for increasing or decreasing the number of the adjustment shims 6 interposed between the focus cam operation ring 4 and the focus cam ring 3 is performed. Decreasing the number of adjustment shims 6 shortens the distance between the focus operation ring 4 and the focus cam ring 3 in the optical axis direction, and increasing the number of adjustment shims 6 increases the distance between the two in the optical axis direction. By performing the adjustment using the adjustment shim 6, the position of the focus cam ring 3 in the optical axis direction can be changed even if the focus operation ring 4 is set to the same rotation position. It becomes possible to adjust the focus of the optical axis position.

  However, in the focus adjustment using this adjustment shim, the adjustable dimension unit is the thickness dimension of the adjustment shim, and therefore, the adjustment amount is a step of the thickness dimension Ls unit of one adjustment shim as shown by the broken line in FIG. Therefore, it is difficult to adjust a dimension smaller than the dimension Ls. Therefore, in the first embodiment, adjustment at the connecting portion between the operation ring portion 41 and the auxiliary ring portion 42 of the focus operation ring 4 is executed in order to increase the accuracy of focus adjustment. That is, the three adjustment screws 43 screwed into the auxiliary ring portion 42 are loosened so that the adjustment screws 43 can be relatively moved in the circumferential direction within the respective arc grooves 412 of the operation ring portion 41. The auxiliary ring portion 42 is rotated relative to the operation ring portion 41 within the range of the arc length of 412 to change the relative rotation positional relationship between them. Then, the three adjustment screws 43 are fastened again, and the operation ring portion 41 and the auxiliary ring portion 42 are integrally connected. As a result, the auxiliary ring portion 42 is moved in the optical axis direction with respect to the outer peripheral fixed ring 5 by the rotation of the auxiliary ring portion 42, and the operation ring portion 41 and the focus cam ring 3 connected thereto are moved along with this movement. Even if the operation ring portion 41 is moved in the optical axis direction, the rotation position of the operation ring portion 41 with respect to the outer peripheral fixed ring 5 is not changed, so that the optical axis position of the focus cam ring 3 with respect to the rotation position of the operation ring portion 41 is changed. It will be. That is, the optical axis position of the focus cam ring 3 with respect to the rotation position of the operation ring portion 41 of the focus operation ring 4 is changed, and further, the optical axis position of the movable lens L2 is changed. In other words, the focus adjustment with the movable lens L <b> 2 can be performed by adjusting the relative rotational position of the auxiliary ring portion 42 and the operation ring portion 41 with the three adjustment screws 43.

That is, when adjusting the rotation position of the operation ring portion 41 with the adjusting screw 43, the auxiliary ring portion 42 is rotated with respect to the operation ring portion 41 within the range of the circumferential length of the arc groove 412 shown in FIG. It is possible to adjust. As shown in FIG. 5, the adjustable rotation range is such that the auxiliary ring portion 42 rotates in the optical axis direction when the auxiliary ring portion 42 rotates by the central angle θa of the circumferential length of the circular arc groove 412 with respect to the outer peripheral fixed ring 5. The length to move. When the central angle of the arc groove 412 is θa and the pitch dimension of the screw grooves 5a and 42a (the length that moves in the optical axis direction when the auxiliary ring portion 42 makes one rotation) is Lp, this length Lx is Lp.
Lx = Lp · (θa / 360)
It is. Therefore, if the length Lx is set to be larger than the dimension Ls as a unit of adjustment by the adjustment shim 6, adjustment in a range longer in the optical axis direction than the adjustment dimension Ls by the adjustment shim 6 becomes possible. On the other hand, the focus adjustment with a dimension smaller than the dimension Ls becomes possible, and the auxiliary ring part 42 can be relatively rotated at a continuous angle with respect to the operation ring part 41, so that the focus adjustment amount is reduced. It becomes possible to carry out while changing continuously. In the first embodiment, the adjustment length Lx is set to twice the dimension Ls due to the adjustment shim 6. Accordingly, instead of increasing or decreasing the number of the adjustment shims 6, it is possible to perform an adjustment corresponding to two adjustment shims 6 only by adjustment with the adjustment screw 43.

  As described above, in the first embodiment, the relative rotation position of the operation ring portion 41 and the auxiliary ring portion 42 of the focus operation ring 4 can be continuously adjusted by the adjustment screw 43. The rotation of the focus cam ring 3 relative to the rotation position 4 and the position in the optical axis direction can be continuously adjusted. Thereby, in addition to the stepwise adjustment of the position of the movable lens L2 in the optical axis direction by the adjustment shim 6, it is possible to adjust the position of the focus lens in the optical axis direction with the continuous characteristic of the movable lens L2 by the adjustment screw 43. Can be continuously and accurately adjusted.

  In the present invention, the central angle (the length in the arc direction) of the arc groove 412 only needs to be equal to or greater than the length corresponding to the thickness of one sheet of the adjustment shim 6, and the length is doubled as in the first embodiment. Good. Needless to say, the size may be twice or more, or twice or less. In the present invention, needless to say, the adjustment by the adjustment shim and the adjustment by the arc groove may be used together. In this case, the central angle of the arc groove is a length corresponding to the thickness of one adjustment shim. If it is, adjustment in a very wide range is possible by increasing or decreasing the number of adjustment shims. Furthermore, the present invention is not limited to the configuration of the first embodiment as long as the relative rotation position of the operation ring portion 41 and the auxiliary ring portion 42 of the focus operation ring 4 can be adjusted. For example, an arc groove may be provided in the auxiliary ring portion, and an adjustment screw may be screwed into the operation ring portion.

  The lens position adjusting device of the present invention is not limited to the focus adjusting device of the first embodiment. For example, a zoom operation of a zoom lens mechanism may be used as long as the lens moves in the optical axis direction when the operation ring is rotated. It is also possible to configure as a zoom adjustment device for adjusting the optical axis positions of the ring and the zoom lens.

It is sectional drawing of the principal part of the lens-barrel of Example 1 of this invention. It is a disassembled perspective view which shows schematic structure of the principal part. It is the front view which looked at the focus operation ring from the optical axis direction. It is an expanded sectional view of the principal part. It is a figure for demonstrating the focus adjustment characteristic by an adjustment shim and an adjustment screw.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed ring 2 Lens support frame 3 Focus cam ring 4 Focus operation ring 5 Outer periphery fixed ring 5a Screw groove 6 Adjustment shim 41 Operation ring part 42 Auxiliary ring part 42a Screw groove 43 Adjustment screw 412 Arc groove L1 Fixed lens L2 Movable lens

Claims (7)

  In a lens barrel including an operation ring supported by a fixed ring with a screw structure and rotated around an optical axis, and a lens that moves in the optical axis direction following the rotation of the operation ring, the operation The ring includes an operation ring portion that is rotated and an auxiliary ring portion that is screwed to the fixed ring, and the operation ring portion and the auxiliary ring portion are configured such that a relative rotation position can be adjusted. A lens position adjusting device.   The cam ring is rotated integrally with the operation ring and moved in the optical axis direction, and the lens follows the rotation of the cam ring and the movement in the optical axis direction by cam means provided on the cam ring. The optical axis direction relative position adjusting means for adjusting the relative position of the operation ring and the cam ring in the optical axis direction is provided. Lens position adjustment device.   The optical axis direction relative position adjusting means is an adjustment shim that is interposed in a connecting portion between the operation ring and the cam ring and adjusts the dimension in the optical axis direction of both. Lens position adjustment device.   A circular arc groove in a circumferential direction is formed in one of the operation ring part and the auxiliary ring part, and the other is configured such that a relative rotation position can be changed along the circular arc groove. Item 4. The lens position adjusting device according to any one of Items 1 to 3.   An adjustment screw for connecting the operation ring portion and the auxiliary ring portion in the arc groove is provided, and the relative rotation position is adjusted by changing the position of the adjustment screw in the arc groove. The lens position adjusting device according to claim 5.   The arc length of the arc groove is characterized in that the distance moved in the optical axis direction when the auxiliary ring portion is rotated by the angle of the arc length is equal to or greater than the thickness dimension of one sheet of the adjustment shim. The lens position adjusting device according to claim 5. 7. The lens position adjusting device according to claim 1, wherein the operation ring is a focus operation ring, and the lens is a lens for focus setting.

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