JP2006072059A - Lens barrel eccentricity adjustment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eccentricity adjustment device for a lens barrel that expands an adjustment range of a position in a direction perpendicular to an optical axis of a lens and enables adjustment to an arbitrary optical axis position.
A lens frame 61 constituting a part of a lens barrel, a lens 6 supported in the lens frame 61, an elastic member 71 that supports the lens 6 movably in a direction perpendicular to the optical axis, A part of the lens holding frame 64 is brought into contact with the peripheral surface of the lens holding frame 64. When the lens holding frame 64 is rotated, the lens holding frame 64 is moved in a direction perpendicular to the optical axis to adjust the eccentric position. The lens 6 can be adjusted in the eccentric range of the eccentric piece 72 because the position of the lens 6 in the direction perpendicular to the optical axis can be adjusted by the eccentric piece 72 while being held elastically supported by the elastic member 71. Adjustment to the optical axis position becomes possible.
[Selection] Figure 3

Description

  The present invention relates to a device for adjusting the optical axis of a lens mounted in a lens barrel with respect to the center of the lens barrel, and in particular, it is possible to adjust the optical axis of a lens to an arbitrary position. Further, the present invention relates to an eccentricity adjustment device that expands the adjustment range.

In a lens barrel provided in an optical device such as a camera, the optical axis position of the lens is set so that the center position of a plurality of lenses supported internally, that is, the optical axis position coincides with the center of the lens barrel cylinder axis. It is necessary to adjust the eccentricity to adjust in the direction perpendicular to the direction. Hereinafter, adjustment in the direction perpendicular to the optical axis of the lens is referred to as eccentricity adjustment. In particular, in recent years, the accuracy required for optical axis adjustment has become severe with the miniaturization of the lens optical system, and it is difficult to satisfy the required optical performance only with the component accuracy. This is because even if individual parts are manufactured within tolerances, assembly errors accumulate and optical performance cannot be satisfied. Therefore, it is necessary to adjust the eccentricity of the lens when assembling the lens barrel in order to minimize the assembly error, and an eccentricity adjusting device for that purpose has been proposed. For example, in patent document 1, it is set as the structure which hold | maintained rotatably the outer peripheral surface of the lens frame of the 2nd lens unit with respect to the internal peripheral surface of the lens frame of the 1st lens unit which comprises the lens barrel, The eccentricity of the second lens unit with respect to the first lens unit is adjusted by adjusting the rotational position of the lens frame of the second lens unit within the lens frame of the first lens unit. Further, in Patent Document 2, an elastic member is interposed between the lens and the lens frame that supports the lens, and the screw amount of the countersunk screw screwed to the lens frame is adjusted around the lens, thereby using a countersunk screw. The amount of deformation of the elastic member in the radial direction is changed, and the lens is adjusted in the radial direction within the lens frame to adjust the eccentricity.
JP 2003-161868 A JP 2001-208946 A

  Since the technique of Patent Document 1 performs eccentric adjustment by rotating the second lens frame with respect to the first lens frame, the adjustable eccentric position is limited to a position on a predetermined arc locus, It cannot be adjusted to an arbitrary optical axis position. Further, since the lens is rotated together with the lens frame, the aberration of the lens may be changed with the rotation of the lens, which may affect the optical characteristics of the lens barrel. The technique of Patent Document 2 is superior to Patent Document 1 in that it can arbitrarily adjust the eccentricity and does not rotate the lens, but the range in which the eccentricity can be adjusted is the amount by which the elastic member is deformed by the countersunk screw. Therefore, since the deformation amount of the elastic member is on the order of several μm at most, there is a problem that it is difficult to perform eccentricity adjustment on the order of several millimeters beyond that. Further, in Patent Document 2, it is difficult to uniquely determine the screwing amount of the countersunk screw and the deformation amount of the elastic member. Therefore, the screwing amount of the countersunk screw becomes the deformation amount of the elastic member as it is, and the eccentricity adjustment of the lens is performed. It is difficult to perform eccentric adjustment with high accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens barrel eccentricity adjustment device that expands the eccentricity adjustment range of the optical axis position of a lens, enables eccentric adjustment to an arbitrary position, and enables high-precision eccentricity adjustment. Is.

  The present invention relates to a lens frame that constitutes a part of a lens barrel, a lens that is supported in the lens frame, and an elastic member that supports the lens in a state movable in a direction perpendicular to the optical axis in the lens frame. A position adjusting member provided on the lens frame, a part of which is in contact with the peripheral surface of the lens, and when operated, the lens is moved in a direction perpendicular to the optical axis to adjust the eccentric position. And

  According to the present invention, the lens is elastically supported in the direction perpendicular to the optical axis in the lens frame, and the lens is operated in the direction perpendicular to the optical axis in the lens frame by operating a position adjusting member provided on the lens frame. Adjust the position. The lens is elastically supported by the elastic member, and the position adjustment member defines the position in the direction perpendicular to the optical axis. Therefore, the lens can be adjusted in the same large range as the adjustment range of the position adjustment member. In addition, adjustment to an arbitrary optical axis position within the position adjustment range by the position adjustment member becomes possible. In addition, the amount of eccentricity can be directly adjusted by the position adjusting member, and highly accurate eccentricity adjustment can be performed.

  In the present invention, the elastic member is composed of a plurality of elastic members that are arranged at a plurality of locations in the circumferential direction of the lens frame and can be deformed in the radial direction of the lens, and the lens is suspended in the lens frame so as to be movable in the radial direction. The structure is supported.

  In the present invention, the position adjusting member is formed of an eccentric piece that can be adjusted in the radial dimension, and the eccentric piece is formed integrally with a screw portion that is screwed into the lens frame in the optical axis direction, and the screw portion. The cylindrical portion is eccentric with respect to the axis of the screw portion, and the circumferential surface of the cylindrical portion of the eccentric piece is in contact with the outer peripheral surface of the lens in the radial direction. In this case, it is preferable that the eccentric pieces are arranged at four locations divided into four equal parts in the circumferential direction of the lens frame. Alternatively, the plurality of elastic members are configured to urge the optical axis position of the lens in one radial direction with respect to the lens frame, and the eccentric coma has a central angle in a circumferential region of the lens frame along the urged radial direction. It is preferable to be disposed at two places where the angle is 90 degrees.

  In the present invention, the lens is fixedly held in a cylindrical lens holding frame, is supported by the lens frame by an elastic member in the lens holding frame, and the position adjustment member abuts on the lens holding frame and can be adjusted in position. . In addition, the elastic member is configured to be formed of an elastic ribbon having an S-shape or a shape close to the S-shape in which one end is connected to the lens frame and the other end is connected to the lens holding frame supporting the lens.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment in which the present invention is applied to a photographing lens of a camera, and shows only one side portion along the optical axis of a lens barrel. Here, the photographing lens is configured as a zoom lens. The lens barrel is a main barrel 1, a zoom ring 2 that is rotatably fitted to the outer periphery of the main barrel 1, and the main barrel 1. And a cam cylinder 3 which is disposed on the inner periphery and is integrally rotated by the zoom ring 2. A first lens frame 41 is internally provided on the inner periphery of the front end side of the main lens barrel 1, and a second lens frame 51 and a third lens frame 61 are provided on the inner periphery of the cam tube 3. The first to third lens frames 41, 51, 61 support the first to third lenses 4, 5, 6, respectively. The lens frames 41, 51, 61 are respectively connected to the main barrel 1. The cam cylinder 3 supports the movement position in each optical axis direction while being supported so as to be movable along the optical axis direction. That is, three cam grooves (not shown) are formed in the cam cylinder 3, and the cam pieces 42, 52 provided integrally with the first to third lens frames 4, 5, 6 respectively. , 62 are inserted into the respective cam grooves, and when the cam cylinder 3 is rotated, the lens frames 41, 51, 61 are moved in the optical axis direction by the engagement between the cam grooves and the cam pieces. is there. Here, in this embodiment, the eccentric adjustment device 7 is configured in the third lens frame 61, and the third lens 6 is supported by the eccentric adjustment device 7 so that the eccentric adjustment can be performed with respect to the third lens frame 61. Has been.

  FIG. 2 is a partially exploded perspective view of the eccentricity adjusting device 7 provided on the third lens 6, and FIG. 3 is a front view as seen from the optical axis direction. 1 is a cross-sectional view of the portion along the line P-P in FIG. 3, and FIG. 4 shows a cross-sectional view of the portion along the line Q-Q in FIG. The third lens frame 61 is configured as an annular frame having a lateral L-shaped cross section, and a part of the diaphragm mechanism 8 is provided on the inner surface thereof, and an annular inner rib 63 is provided. It is integrally formed to project toward the inner diameter direction. An annular lens holding frame 64 is fitted to the peripheral surface of the third lens 6, and the third lens 6 is disposed at the inner peripheral position of the inner rib 63 of the third lens frame 61 via the lens holding frame 64. ing. The outer diameter dimension of the lens holding frame 64 is slightly smaller than the inner diameter dimension of the inner rib 63, and therefore, 1 between the outer peripheral surface of the lens holding frame 64 and the inner peripheral surface of the inner rib 63 is 1 in the radial direction. A gap with a minute dimension of about ˜2 mm is generated, and the eccentricity of the third lens 6 can be adjusted within the third lens frame 61 by this gap dimension.

  The eccentricity adjusting device 7 includes elastic ribbons 71 that are bent into S-shapes at four circumferential portions equally arranged in the circumferential direction of the third lens frame 61 and elastically deformable in the radial direction. The lens holding frame 64 is supported by these elastic ribbons 71 in a state of being suspended in the third lens frame 61. That is, the elastic ribbon 71 is formed by molding rubber or elastic resin, and locking pieces 71a and 71b having a large thickness are formed integrally at both ends, respectively. One 71a is fitted into a T-shaped groove 65 formed on the outer peripheral surface of the lens holding frame 64, and the other 71b is inserted into a T-shaped groove 66 formed on the inner peripheral surface of the third lens frame 61. It is inserted. At this time, each elastic ribbon 71 is inserted in a state of being slightly expanded by its own elasticity, and the lens holding frame 64 is stretched in the outer diameter direction by the elastic ribbon 71 at four locations around the circumference, and the third lens. The frame 61 is elastically supported. Therefore, the elastic ribbon 71 is elastically deformed in the length direction, so that the lens holding frame 64 can move in the surface direction perpendicular to the optical axis of the main barrel 1 in the third lens frame 61. . The amount by which the lens holding frame 64 moves in the radial direction is a gap size generated by the difference between the inner diameter of the inner rib 63 and the outer diameter of the lens holding frame 64 as described above.

  Further, the third lens frame 61 is provided with a semicircular recess 67 having an inner peripheral surface recessed in the outer diameter direction at four circumferential positions sandwiching the elastic ribbon 71 in the circumferential direction. Is secured, and an eccentric piece 72 is disposed in the space in each recess 67. The eccentric piece 72 is screwed to the front surface of the inner rib 63 in the optical axis direction, and is formed integrally with the screw portion 72a, and the center is displaced with respect to the axis of the screw portion 72a. A cylindrical portion 72b is provided, and is screwed in the optical axis direction to the front surface of the inner rib 63 through one opening of the main barrel 1 in the optical axis direction. The circumferential surface of the cylindrical portion 72b of the eccentric piece 72 is in contact with the outer peripheral surface of the lens holding frame 64, and the cylindrical portion 72b is eccentrically rotated by rotating the screw portion 72a. Only the lens holding frame 64 can be moved in the radial direction.

  In this eccentricity adjusting device 7, when the screw portion 72a of the eccentric piece 72 is rotated by a predetermined angle as shown in FIG. 5 with some eccentric pieces 72, as shown in FIG. 5A, the screw portion 72a. The cylindrical portion 72b integral with the outer peripheral surface is eccentrically rotated, and the circumferential surface presses the outer peripheral surface of the lens holding frame 64 in the inner diameter direction, or, as shown in FIG. Try to leave. When the lens holding frame 64 is pressed in the inner diameter direction, the elastic ribbons 71 on both sides sandwiching the eccentric piece 72 in the circumferential direction are extended, and the lens holding frame 64 is moved in the inner diameter direction. When the elastic ribbons 71 are separated in the outer diameter direction, the elastic ribbons 71 on both sides are shortened, and the lens holding frame 64 is moved in the outer diameter direction. In any case, since the circumferential surface of the eccentric piece 72 and the outer circumferential surface of the lens holding frame 64 are always in contact with each other by the elastic force of the elastic ribbon 71, the lens holding frame 64 is moved to the third lens by the eccentric piece 72. 6 is adjusted eccentrically, and when the adjustment is completed, the lens holding frame 64 is supported stably by the eccentric adjustment position 7 because the outer peripheral surface of the lens holding frame 64 is supported by the four eccentric pieces 72. Will be.

  As described above, the eccentric adjustment of the third lens 6 by the lens holding frame 64 is performed by the amount of eccentricity of the eccentric piece 72 within the range of the radial gap between the lens holding frame 64 and the inner rib 63. It is possible to make adjustments. Therefore, if the eccentric amount of the eccentric piece 72 is made larger than the gap dimension, the eccentric adjustment of 1 to 2 mm which is the gap dimension of the present embodiment is possible, which is extremely large compared to the technique of Patent Document 2. The eccentricity adjustment of the dimensional range can be realized. Further, as the eccentric operation of the four eccentric pieces 72 is performed, as shown in FIG. 3, the lens holding frame 64 can be adjusted in any direction in the X and Y directions within a plane perpendicular to the optical axis. As in Patent Document 1, the eccentric position is not limited. In particular, the lens holding frame 64 is in direct contact with the eccentric piece 72 on the outer peripheral surface, and the amount of eccentricity of the eccentric piece 72 becomes the amount of eccentricity adjustment of the lens 6 as it is. The eccentricity can be adjusted with higher accuracy than the configuration in which the amount of eccentricity is determined by the amount. Further, since the lens holding frame 64 adjusted in eccentricity is sandwiched in the radial direction by the four eccentric pieces 72, the eccentric position is maintained even if the elastic force of the elastic ribbon 71 is deteriorated. Furthermore, the eccentricity adjustment work only needs to be performed by rotating and adjusting the four eccentric pieces 72, and no other work is required, so that it can be performed very easily and quickly.

  FIG. 6 is a front view of the eccentricity adjusting apparatus according to the second embodiment of the present invention, and is the same view as FIG. 3 according to the first embodiment. Parts equivalent to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. This embodiment is characterized in that the number of eccentric pieces is reduced. That is, the eccentric pieces 72 are arranged at three positions arranged in three equal parts in the circumferential direction of the third lens frame 61, respectively. The other configuration is the same as that of the first embodiment, and elastic ribbons 71 are arranged at four positions that are equally spaced in the circumferential direction, and the lens holding frame 64 is elastically suspended in the third lens frame 61. Suspended and held. It is possible to adjust the lens holding frame 64 to an arbitrary optical axis position only by providing three eccentric pieces 72 as in this embodiment, and the configuration can be simplified by reducing the number of eccentric pieces 72. become. Further, the eccentric adjustment can be performed quickly and easily.

  Fig.7 (a) is a front view of the eccentricity adjustment apparatus of Example 3 of this invention. In this embodiment, the number of eccentric pieces is further reduced, and two eccentric pieces 72 are formed. In other words, the eccentric pieces 72 are arranged at two positions that form 90 degrees in the circumferential direction of the third lens frame 61 with respect to the optical axis. The other configuration is the same as that of the first embodiment, but the four elastic ribbons 71 that suspend and support the lens holding frame 64 are provided as one elastic ribbon 71A that is sandwiched between two eccentric pieces 72 in the circumferential direction. Is different from the first and second embodiments in that it is set to be slightly larger than the elastic force of the other three elastic ribbons 71.

  In the third embodiment, in the state before the eccentricity adjustment, as shown in FIG. 7A, the lens holding frame 64 is pulled by the elastic ribbon 71A having a large elastic force. The third lens 6 is normally elastic having a larger elastic force than the optical axis of the main lens barrel. The optical axis is shifted to the ribbon 71A side and is deflected. Then, as shown in FIG. 7B, the third lens 6 is moved to the main mirror by adjusting the two eccentric pieces 72 and moving the lens holding frame 64 in a direction other than the upper right in the figure. It is possible to match the optical axis of the cylinder 1. The lens holding frame 64 adjusted in eccentricity is held in the adjustment position by the elastic force of the elastic ribbons 71 and 71A and the radial abutment force by the two eccentric pieces 72. Thereby, the configuration of the eccentricity adjustment device can be further simplified, and accordingly, the eccentricity adjustment can be performed more easily and quickly.

  Here, in each of the above embodiments, the lens holding frame is suspended and supported by elastic ribbons at four positions in the circumferential direction. However, the lens holding frame is suspended and supported only by providing elastic ribbons at three positions in the circumferential direction. The configuration of the eccentricity adjusting device can be further simplified by reducing the number of elastic ribbons. Further, the configuration of the elastic ribbon is not limited to the shape of the embodiment, and any shape elastic member can be used as long as the lens holding frame can be elastically supported in the third lens frame. It is.

  The eccentric piece is not limited to the configuration of the embodiment as long as it can be operated from the outside of the lens barrel. However, the configuration of the embodiment can be adjusted by operating the eccentric piece through the opening of the lens barrel, which is advantageous for easy adjustment.

  The present invention is not limited to the photographing lens of a camera, but can be similarly applied to lens barrels of various optical apparatuses that require adjustment of the decentering of the lens optical axis.

It is sectional drawing of the principal part of Example 1 (PP sectional view taken on the line of FIG. 3). 2 is a partial exploded perspective view of a main part of Example 1. FIG. It is the figure which looked at the principal part of Example 1 from the optical axis direction. It is sectional drawing which follows the QQ line of FIG. It is a schematic diagram for demonstrating operation | movement of an eccentric top. It is the figure which looked at the principal part of Example 2 from the optical axis direction. It is the figure which looked at the principal part for demonstrating the structure and operation | movement of Example 3 from the optical axis direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main barrel 2 Zoom ring 3 Cam cylinder 4 1st lens 5 2nd lens 6 3rd lens 7 Eccentricity adjustment apparatus 8 Aperture 61 3rd lens frame (lens frame)
64 Lens holding frame 65, 66 (T-shaped) groove 67 Recess 71, 71A Elastic ribbon 72 Eccentric piece

Claims (7)

  An eccentricity adjustment device for adjusting the optical axis of a lens supported internally in the lens barrel with respect to the center of the lens barrel, the lens frame constituting a part of the lens barrel; A lens supported in the lens frame, an elastic member for supporting the lens in a state movable in a direction perpendicular to the optical axis in the lens frame, and a part of the lens provided in the lens frame. A lens barrel eccentricity adjusting device comprising: a position adjusting member that is in contact with a peripheral surface and adjusts an eccentric position by moving the lens in the vertical direction when operated.   The elastic member is provided at a plurality of locations in the circumferential direction of the lens frame, and includes a plurality of elastic members that can be deformed in the radial direction of the lens, and the lens is suspended in the lens frame so as to be movable in the radial direction. 2. The lens barrel eccentricity adjusting device according to claim 1, wherein the lens barrel is eccentrically supported.   The position adjusting member includes an eccentric piece that can be adjusted in a radial dimension, and the eccentric piece is integrally formed with the screw portion that is screwed into the lens frame in the optical axis direction. 3. A cylindrical portion eccentric with respect to an axis of the screw portion, and a circumferential surface of the cylindrical portion of the eccentric piece is in contact with an outer peripheral surface of the lens in a radial direction. The lens barrel eccentricity adjusting device as described in 1.   4. The lens barrel eccentricity adjusting device according to claim 3, wherein the eccentric pieces are arranged at four locations divided into four equal parts in a circumferential direction of the lens frame. 5.   The plurality of elastic members are configured to bias the optical axis position of the lens in one radial direction with respect to the lens frame, and the eccentric piece is a circumference of the lens frame along the biased radial direction. 4. The lens barrel eccentricity adjusting device according to claim 3, wherein the lens barrel is disposed at two locations having a central angle of 90 degrees in the region.   The lens is fixedly supported in a cylindrical lens holding frame, and the lens holding frame is supported by the lens frame by the elastic member, and the position adjusting member is configured to be in contact with the lens holding frame so that the position can be adjusted. 6. The lens barrel eccentricity adjusting device according to claim 1, wherein the lens barrel eccentricity adjusting device is provided. The elastic member is formed of an S-shaped elastic ribbon having one end connected to the lens frame and the other end connected to a lens holding frame that supports the lens. The decentering adjustment device for a lens barrel according to any one of claims 1 to 6.

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