JP2006113315A - Collimation device and collimation method for lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collimation device and collimation method for a lens barrel which enable easy collimation of lenses at high accuracy when the lens barrel is assembled. <P>SOLUTION: The collimation device 100 is used for collimating both first lens 7 and second lens 8 when the lens barrel is assembled by integrating respective lens frames 71 and 81 for the first and second lenses 7 and 8, in the directions of their optical axes. The collimation device 100 has, in a ring body 101, a first opening 110 in which the first lens frame 71 is fitted and a second opening 120 in which the second lens frame 81 is fitted so that both openings are disposed adjacent to each other in the optical axis direction. By fitting the first lens frame 71 and the second lens frame 81 into the first opening 110 and second opening 120 respectively, the respective optical axes of the lenses 7 and 8 are positioned and thus the first and second lenses 7 and 8 are automatically collimated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical axis adjusting device for adjusting the optical axes of a plurality of lenses when assembling a lens barrel composed of a plurality of lenses, and an optical axis adjusting method using the optical axis adjusting device. It is.

In a lens barrel provided in an optical device such as a camera, it is necessary to adjust the optical axis positions of a plurality of lenses that are internally supported with respect to the lens barrel. Particularly in recent years, the accuracy required for the optical axis position has become severe as the lens optical system becomes smaller, 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, an error occurs on the imaging surface due to the optical axis error of the lens, and aberrations appear. In order to correct aberration due to such an optical axis error, conventionally, the optical axis of the lens is adjusted when the lens barrel is assembled, and an optical axis adjusting device for that purpose has been proposed. For example, in Patent Document 1, when two lenses are supported on one lens frame, one lens is fixedly supported with respect to the lens frame, while the other lens is placed between the lens frame. A lens pressing ring made of an elastic member is interposed, and a plurality of countersunk screws are screwed to the elastic member and the lens frame around the lens. In this patent document 1, after assembling two lenses into a lens frame, individual counter screws arranged around the other lens are manually operated to adjust the screwing amount to the lens frame, thereby adjusting the countersunk screws. Thus, the lens pressing ring is deformed in the radial direction, and the optical axis is adjusted by adjusting the position of the other lens in the radial direction in the lens barrel by this deformation force.
JP 2001-208946 A

  As an apparatus for adjusting the lens optical axis in such a lens barrel, as represented by the technique of Patent Document 1, the optical axis of the lens is adjusted with respect to the lens frame, or the lens frame that supports the lens is used as the lens mirror. The optical axis is adjusted with respect to the cylinder, but in any adjustment, the multiple screws etc. arranged around the lens are tightened to adjust the lens while slightly displacing it in the radial direction. Yes. This is because since two lenses are supported by one lens frame, it is difficult to support both lenses at the correct optical axis position with respect to the lens frame. In other words, the lens frame that supports the two lenses has a relatively long length in the optical axis direction. Therefore, when processing the lens frame, a tilt in the optical axis direction of the tolerance occurs on the inner peripheral surface of the lens frame. This is because the inclination in the optical axis direction appears as it is as an eccentricity of the optical axis between the two lenses. When adjusting the optical axis deviation generated in this way using the technique of Patent Document 1 as described above, it is possible to adjust the lens in the XY directions on a plane perpendicular to the optical axis only by operating one screw. Therefore, the optical axis adjustment must be performed while simultaneously operating two or more screws, and the adjustment work for performing the optical axis adjustment with high accuracy becomes complicated. In addition, since the lens is simultaneously displaced in the X and Y directions during the optical axis adjustment, it is difficult to set the optical axis at a desired position, and skill is required for adjustment, and the adjustment time is long and workability is poor. There is also a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical axis adjusting device and an optical axis adjusting method for a lens barrel capable of easily and accurately performing optical axis adjustment when assembling a lens barrel.

  The present invention is based on the premise that a lens barrel is assembled by integrating a first lens frame supporting a first lens and a second lens frame supporting a second lens in the optical axis direction. An optical axis adjusting device used for assembling, wherein a first opening having an inner peripheral surface to which an outer peripheral surface of a first lens is fitted and an outer peripheral surface of a second lens are fitted A second opening having a peripheral surface is provided adjacent to the axial direction. For example, each of the first and second lens frames is formed in an annular shape, and each of the first and second openings is formed to have an inner diameter that fits the outer peripheral surface of each lens frame. Here, it is preferable that the first opening is provided at one end portion in the axial direction, and the second opening is configured by an annular body provided at the opposite end portion in the axial direction. Moreover, it is preferable that each axial position of the 1st opening and the 2nd opening is coaxial, or is eccentric by the required dimension.

  In the present invention, when the first and second lenses are assembled side by side in the optical axis direction, the first lens frame that supports the first lens is fitted into the first opening provided in the optical axis adjusting device. Then, the second lens frame that supports the second lens is fitted in the second opening provided in the optical axis adjusting device and aligned in the axial direction with the first opening, and both lens frames are fitted. It is characterized by being integrated in a state. Here, an optical axis adjusting device including a first opening and a second opening formed with an eccentric dimension corresponding to the eccentric dimension required between the first lens and the second lens is used. .

  According to the present invention, the first lens frame supporting the first lens is fitted in the first opening of the optical axis adjusting device, and the second lens frame supporting the second lens in the second opening. When these are fitted, both lenses are positioned, and the optical axes of the first lens and the second lens are automatically adjusted. Therefore, it is possible to assemble the lens adjusted in the optical axis by integrally connecting both lenses fitted in each opening in that state, so that the operation of adjusting the optical axis while moving the lens becomes unnecessary. Adjustment work can be simplified, and the optical axis can be adjusted with high accuracy. Further, in the case of the optical axis adjusting device in which the first opening and the second opening are decentered by a required dimension, the first lens and the second lens are rotated by rotating the optical axis adjusting device around the axis. The optical axis can be adjusted. Alternatively, the optical axes of the first lens and the second lens can be adjusted by changing the amount of eccentricity between the first opening and the second opening.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of one side portion of a photographing lens of a camera assembled using the optical axis adjusting device of the present invention, broken along the optical axis of the 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 front lens frame 41 is internally provided on the inner periphery of the front end side of the main barrel 1, and an intermediate lens frame 51 and a rear lens frame 61 are provided on the inner periphery of the cam tube 3. The front, middle, and rear lens frames 41, 51, and 61 support the front, middle, and rear lenses 4, 5, and 6, respectively. The main barrel 1 is supported so as to be movable along the optical axis direction, and the cam barrel 3 sets a movement position in each optical axis direction. That is, three cam grooves (not shown) are formed in the cam cylinder 3, and cam pieces 42 provided integrally with the front, middle, and rear lens frames 4, 5, and 6, respectively. , 52, 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.

  Further, as shown in an enlarged view in FIG. 2, the rear lens 6 is composed of a first lens 7 and a second lens 8, and a first lens that supports the first lens 7. A second lens frame 81 that supports the second lens 8 is connected to the frame 71 by screws 10. The second lens frame 71 is formed in an annular shape having a slightly smaller outer diameter than the second lens frame 81, supports the second lens 8 on its inner peripheral surface, and has a plurality of circumferential directions. It is fastened to and integrated with the side surface of the first lens frame 71 by screws 10 arranged in four places, here. The first lens frame 71 is supported inside the rear lens frame 61. The rear lens frame 61 is integrally provided with a diaphragm drive unit 9, but detailed description thereof is omitted here.

  FIG. 3 is an external perspective view of an optical axis adjusting device used when the second lens frame is assembled with the rear lens, that is, the first lens frame. 4A is a front view of the optical axis adjusting device viewed from the optical axis direction, and FIG. 4B is an enlarged sectional view taken along the line AA. The optical axis adjusting device 100 has a cylindrical shaft length slightly longer than at least the length of the second lens frame 71 in the optical axis direction, and has an outer diameter larger than the outer diameter of the first lens frame 71. It is formed as a torus 101. In addition, the inner peripheral surface of the torus 101 is formed in a state of being divided into a first opening 110 and a second opening 120 having different inner diameter dimensions in the optical axis direction. The inner diameter dimension of the inner peripheral surface 111 of the first opening 110 on the left side of the figure is substantially equal to the outer diameter dimension of the first lens frame 71, and the inner diameter dimension of the inner peripheral surface 121 of the second opening 120 on the right side of the figure is The outer diameter of the second lens frame 81 having a smaller diameter is substantially equal to the outer diameter of the second lens frame 81. In this embodiment, the inner diameter of the first opening 110 is larger than the inner diameter of the second opening 120. Yes. Further, in this optical axis adjusting device, the first opening 110 and the second opening 120 are formed coaxially.

  Such an optical axis adjusting apparatus 100, in other words, an optical axis adjusting jig, can easily manufacture a material having a small thermal expansion change with respect to an environmental temperature change by cutting such as a lathe. Alternatively, it can also be manufactured by a casting method that provides high dimensional accuracy.

  In the method of assembling the lens barrel shown in FIG. 1, the front lens 4 is supported by the front lens frame 41 and the intermediate lens 5 is supported by the intermediate lens frame 51. Further, for the rear lens frame 61, the first lens 7 is supported by the first lens frame 71, and the second lens 8 is supported by the first lens frame 71. The frame 81 is fixed and integrated. Then, the integrated first and second lens frames 71 and 81 are supported by the rear lens frame 61. Accordingly, the front, middle, and rear lens frames 41, 51, and 61 are each assembled to the main barrel 1. At this time, the front, middle, and rear lenses 4, 5, and 6 (7, 8) are assembled by assembling the front, middle, and rear lens frames 41, 51, and 61 with respect to the main barrel 1, respectively. Assembling is performed in a state where the optical axis of the main barrel 1 is adjusted almost automatically. Further, the first lens frame 71 and the second lens frame 81 supported in the rear lens frame 61 are fixed to each other with screws. Since the first lens frame 71 and the second lens frame 81 have short dimensions in the optical axis direction, the inclination in the optical axis direction on the inner peripheral surface due to tolerance can be ignored, so the first lens 7 and the second lens 8 can be supported in a state where the optical axis position is set with high accuracy. However, when connecting the first lens frame 71 and the second lens frame 81, it is before being supported in the rear lens frame 61, so that the first lens 7 and the second lens 8 are connected. There is a risk of optical axis misalignment between them. Therefore, when the second lens frame 81 is fixed to the first lens frame 71, the optical axis adjustment of the second lens 8 with respect to the first lens 7 is performed using the optical axis adjustment device 100 shown in FIG. Execute.

  FIG. 5 is a diagram for explaining this optical axis adjustment. The first lens 7 is previously supported by the first lens frame 71, and the second lens 8 is supported by the second lens frame 81. At this time, the lenses 7 and 8 can be supported with high precision in the both lens frames 71 and 81 as described above. Then, the first lens frame 71 is inserted from the front end side in the optical axis direction of the annular body 101 of the optical axis adjusting device 100, and the outer periphery of the first lens frame 71 is inserted into the inner peripheral surface 111 of the first opening 110. Fit the faces. At this time, the end edge portion of the first lens frame 71 abuts on the step portion 102 formed at the boundary between the large-diameter first opening 110 and the small-diameter second opening 120, and axial positioning is performed. . On the other hand, the second lens frame 81 is inserted from the rear end side in the optical axis direction of the annular body 101 of the optical axis adjusting device 100, and the outer peripheral surface of the second lens frame 81 is inserted into the inner peripheral surface 121 of the second opening 120. Mate. By inserting the first lens frame 71 and the second lens frame 81 into the torus 101 in this way, both the lens frames 71 and 81 are respectively in the torus 101 inside the first opening 110. As a result, both the lens frames 71 and 81 are arranged coaxially according to both the openings 110 and 120. Therefore, the light of the second lens 8 with respect to the first lens 7 is obtained by fastening the four screws 10 in the circumferential direction in this state and fixing the second lens frame 81 to the first lens frame 71. Axis adjustment is realized.

  As described above, the optical axis adjusting device 100 shown in FIGS. 3 and 4 includes the first lens frame 71 and the first lens frame in the first opening 110 and the second opening 120, which are formed coaxially in advance in the annular body 101, respectively. It is possible to adjust the optical axes of the first lens 7 and the second lens 8 by positioning both lens frames 71 and 81 simply by inserting and fitting the second lens frame 81. Therefore, since the optical axis adjustment of the lens is automatically performed according to the openings 110 and 120 formed in the torus 101, the diameter of one of the lenses 7 or 8 is adjusted while tightening the plurality of screws 10. The operation of adjusting the optical axis while moving in the direction becomes unnecessary, the adjustment work can be simplified, and the optical axis can be adjusted with high accuracy.

  FIG. 6 is a front view of the optical axis adjusting device 100A according to the second embodiment as viewed from the optical axis direction. Portions equivalent to those of the optical axis adjusting device in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted, but in this optical axis adjusting device 100A, the second opening 120 with respect to the first opening 110. Is eccentric by a dimension C in the vertical direction (Y direction) in FIG.

  The optical axis adjustment using the optical axis adjustment device 100A of FIG. 6 is the same as the optical axis adjustment using the optical axis adjustment device of FIG. That is, referring to FIG. 5 again, the first lens frame is inserted from the front end side in the optical axis direction of the optical axis adjusting device 100A, and the first lens frame 71 is fitted to the inner peripheral surface of the first opening 110. . Further, the second lens frame 81 is inserted from the rear end side in the optical axis direction of the optical axis adjusting device 100 </ b> A, and the second lens frame 81 is fitted to the inner peripheral surface of the second opening 120. Then, by fastening the four screws 10 in the circumferential direction and fixing the second lens frame 81 to the first lens frame 71, the optical axis of the second lens 8 with respect to the first lens 7 is secured. Adjustment is realized.

  Thus, by inserting the first lens frame 71 and the second lens frame 81 into the openings 110 and 120 of the annular body 101 of the optical axis adjusting device 100A, the both lens frames 71 and 81 are respectively the first lens frame 71 and 81. In particular, in the case of the optical axis adjusting device 100A, the second lens 8 is decentered by the dimension C in the Y direction with respect to the first lens 7. Will be assembled. Therefore, in the case where aberration is caused by these lenses due to manufacturing errors of the first lens 7 or the second lens 8, it is possible to correct the aberration by decentration occurring between both lenses. Even in this case, since the optical axes of both the lenses 71 and 81 are automatically adjusted according to the first opening 110 and the second opening 120 of the torus 101, a plurality of screws 10 are tightened. There is no need to adjust the optical axis while moving the lens while loosening, the adjustment work can be simplified, and the optical axis can be adjusted with high accuracy. In the second embodiment, the first lens 7 and the second lens 8 are decentered by rotating only the optical axis adjusting device 100A with the lens frames 71 and 81 inserted into the openings 110 and 120, respectively. It is possible to adjust in the X direction and the Y direction, and it is also possible to adjust the amount of eccentricity.

  FIGS. 7A and 7B are a front view and an arrow B view of the optical axis adjusting apparatus 100B of the third embodiment in which the eccentric dimensions of the first lens and the second lens can be adjusted. The optical axis adjusting device 100B includes a first annular body 101A in which a first opening 110 is formed and a second annular body 101B in which a second opening 120 is formed. The toric bodies 101A, 101B are arranged side by side in close contact with each other in the axial direction. Both annular bodies 101A and 101B are formed with tapered surfaces 104 inclined at a required angle (for example, 45 degrees) with respect to the axial direction at two locations along the X axis, and both annular bodies 101A and 101B are tapered. The surfaces 104 are in close contact with each other. As a result, the two toroids 101A and 101B can move relative to each other along the X-axis direction in a state of sliding contact with each other on the tapered surface 104. Further, both toric bodies 101A and 101B are connected to a micrometer 103, and when the micrometer 103 is operated, both toric bodies 101A and 101B are relatively moved in the X direction.

  The optical axis adjustment device 100B can move the second torus 101B relative to the first torus 101A in the X-axis direction by operating the micrometer 103, and the first opening 110 can be moved. It is possible to adjust the amount of eccentricity of the second opening 120 with respect to. That is, it is possible to increase the amount of eccentricity by moving the second torus 101B in the Y direction from the state where the second opening 120 is positioned coaxially with respect to the first opening 110. When the optical axes of the first lens 7 and the second lens 8 are adjusted using the optical axis adjusting device 100B, the first lens 7 and the second lens are checked by checking the scale of the micrometer 103. 8 can be confirmed at a glance, and high-precision optical axis adjustment can be realized. Moreover, since the amount of eccentricity can be set arbitrarily, it is not necessary to prepare a plurality of optical axis adjusting devices having different amounts of eccentricity, which is advantageous for cost reduction. Also in the third embodiment, the eccentricity of the first lens 7 and the second lens 8 can be reduced by rotating only the optical axis adjusting device 100B with the lens frames 71 and 81 inserted into the openings 110 and 120, respectively. Not only the axial direction but also the Y-axis direction and further the XY-axis direction can be adjusted, and the amount of eccentricity can also be adjusted.

  Here, as shown in FIG. 8 showing an improved example of the optical axis adjusting apparatus 100A of the second embodiment, when it is required to perform circumferential positioning when assembling the lens, for example, the torus 101 Grooves 112 and 122 extending in the axial direction are formed in a part of the circumference of each inner circumferential surface of the first opening 110 and the second opening 120. Further, although not shown in the drawing, a protruding strip extending in the axial direction is formed on a part of the outer peripheral surface of each of the first lens frame 71 and the second lens frame 82 in the circumferential direction. Then, when the lens frames 71 and 81 are inserted and fitted into the openings 110 and 120, respectively, the protrusions are fitted into the grooves 112 and 122, respectively. As a result, when the lens frames 71 and 81 are inserted into the openings 110 and 120, the relative circumferential positions of the lenses 7 and 8 can be defined. This optical axis adjusting device is effective when the decentering direction between both lenses 7 and 8 is decentered in a specific direction in the X-axis direction or Y-axis direction.

  If it is difficult to form concave grooves or ridges in terms of processing, place a mark on the circumference of the torus, and put a similar mark on the lens frame to adjust the optical axis. Sometimes, the lens frame may be fitted into the opening while aligning both marks.

  Here, although illustration is omitted, if a plurality of optical adjustment devices having different amounts of eccentricity of the front end side opening and the rear end side opening are prepared, it is required when assembling the first lens and the second lens. Assembling with an appropriate eccentric dimension can be realized simply by selecting an optical adjusting device having an eccentric amount corresponding to the eccentric amount and assembling both lenses.

  The present invention can be applied not only to the photographing lens of a camera but also to lens barrels of various optical devices that require adjustment of the optical axis of the lens optical axis.

It is sectional drawing of the lens-barrel to which this invention is applied. It is sectional drawing of the principal part of a rear side lens. It is an external appearance perspective view of an optical axis adjusting device. It is the front view and AA line expanded sectional view of the optical axis adjustment apparatus of FIG. It is sectional drawing for demonstrating the optical axis adjustment method. It is a front view of the modification of an optical axis adjustment apparatus. It is the front view and B arrow view of the modification of an optical axis adjusting device. It is a front view of the example of improvement of an optical axis adjusting device.

Explanation of symbols

1 Main barrel 2 Zoom ring 3 Cam barrel 4 Front lens 5 Intermediate lens 6 Rear lens 7 First lens 8 Second lens 9 Aperture drive unit 10 Screw 61
71 1st lens frame 81 2nd lens frame 100,100A, 100B Optical axis adjustment apparatus 101,101A, 101B Torus 110 1st opening 120 2nd opening

Claims (7)

  An optical axis adjustment device for assembling a lens barrel by integrating a first lens frame supporting a first lens and a second lens frame supporting a second lens in the optical axis direction, A first opening having an inner peripheral surface into which the outer peripheral surface of the first lens frame is fitted, and a second opening having an inner peripheral surface into which the outer peripheral surface of the second lens frame is fitted. An optical axis adjusting device for a lens barrel, which is provided adjacent to the axial direction.   Each of the first lens frame and the second lens frame is formed in an annular shape, and each of the first and second openings is formed to have an inner diameter dimension in which an outer peripheral surface of each lens frame is fitted. The optical axis adjusting device of the lens barrel according to claim 1.   The said 1st opening is provided in the one end part of the axial direction, and the said 2nd opening is comprised by the torus provided in the opposite side edge part of the axial direction, The 1st or 2 characterized by the above-mentioned. The optical axis adjusting device of the lens barrel described in 1.   4. The optical axis adjustment device for a lens barrel according to claim 1, wherein each of the first opening and the second opening has an axial position that is coaxial or eccentric with a required dimension. .   The first opening and the second opening are formed as separate members, respectively, and the two members can be moved relative to each other in a direction perpendicular to the optical axis direction so that the eccentric amount of both openings can be adjusted. The optical axis adjusting device for a lens barrel according to any one of claims 1 to 3.   When assembling the first and second lenses side by side in the optical axis direction, the first lens frame supporting the first lens is fitted into the first opening provided in the optical axis adjusting device, and the second lens A second lens frame supporting the lens is fitted in a second opening provided in the optical axis adjusting device and aligned in the axial direction with the first opening, and the both lens frames are fitted. A method of adjusting an optical axis of a lens barrel, characterized by integrating. Corresponding to an eccentric dimension required between the first lens and the second lens, an optical axis adjusting device including a first opening and a second opening formed with the eccentric dimension is used. The method of adjusting an optical axis of a lens barrel according to claim 6

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