JP4730500B2 - Lens device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens apparatus, and more particularly to a lens apparatus applied to a small-sized and high-pixel digital camera.
[0002]
[Prior art]
In recent digital cameras, as the CCD (solid-state imaging device) has become higher in pixel size and smaller in size, the lens device is also required to have high precision. It is necessary to lose.
[0003]
In a lens apparatus (lens apparatus such as Japanese Patent Laid-Open No. 9-113791) configured to perform zooming and focusing by changing the interval between a plurality of lenses, the tolerance of each part may be added, resulting in an increase in assembly error. In addition, the above-described tilting and axial deviation occur excessively.
[0004]
Therefore, in the conventional lens device, one of the plurality of guide shafts supporting the lens frame is cantilevered on the lens barrel, and the lens frame is moved by shaking the free end of the guide shaft. By adjusting, the tilt of the lens and the axis deviation were adjusted. After the adjustment, the free end of the guide shaft is fixed to the lens barrel.
[0005]
[Problems to be solved by the invention]
However, the above-described conventional lens device that adjusts the tilting and axial deviation of the lens by swinging the guide shaft has the following drawbacks. That is, when the guide shaft is fixed in a state where it is not parallel to the optical axis but is tilted, the parallel arrangement relationship of the plurality of guide shafts is lost, and the slidability of the lens frame is deteriorated. In addition, since the conventional adjustment method is mainly a method of adjusting the tilt, there is a drawback that an axis deviation may occur during the tilt adjustment, and the optical performance may be deteriorated.
[0006]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lens device capable of improving optical performance by improving a structure for adjusting the tilting and axial displacement of the lens.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a lens apparatus in which a guide shaft is disposed in parallel with an optical axis in a lens barrel, and the lens frame is supported by the guide shaft. A guide shaft main body part, and a bearing part formed at both ends of the guide shaft main body part and having a central axis that is eccentric with respect to the central axis of the guide shaft main body part. The central shaft is coaxial, and the guide shaft main body portion rotates eccentrically around the central axis of the bearing portion by each of the bearing portions being rotatably supported by the lens barrel. It is a feature.
[0008]
According to the present invention, when the guide shaft is rotated around the central axis of the bearing portion, the guide shaft main body portion rotates eccentrically around the central axis of the bearing portion, so that the lens frame supported by the guide shaft main body portion. Is operated by the guide shaft main body and moves in a plane orthogonal to the optical axis. As a result, the optical axis of the lens can be aligned.
[0009]
In the present invention, since the guide shaft is arranged in parallel with the optical axis, the central axis of the guide shaft (the central axis of the bearing portion) remains in parallel with the optical axis even when the guide shaft is rotated. Rotate with. Therefore, even if the guide shaft is rotated, the guide shaft does not fall down, so that only the adjustment of the axis deviation needs to be carried out, and the sliding performance of the lens frame with respect to the guide shaft can be prevented. Furthermore, in the case of a lens device having a plurality of guide shafts, the guide shaft of the present invention is applied to each guide shaft, so that the degree of freedom in the adjustment direction of the lens is widened and fine adjustment is possible.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a lens apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0011]
FIG. 1 is an external view of an electronic still camera 100 to which a lens apparatus according to the present invention is applied. On the front surface of the camera body 100A of the electronic still camera 100, a lens device 102, a finder window 103, a flash light control sensor 104, and a self-timer lamp 105 are disposed at predetermined positions. Further, a pop-up strobe 106 and a release switch 107 are disposed on the upper surface of the main body 100A, and various operation buttons including a viewfinder eyepiece, a liquid crystal display panel, and a power button (not shown) are provided on the rear surface of the main body 100A. They are arranged at predetermined positions. The lens device 102 is of a retractable / retractable type, and when the power is turned on with the power button, the lens barrel 108 is extended forward from the front surface of the main body 100A.
[0012]
As shown in FIG. 2, the lens device 102 includes a first lens 12, a second lens group 14, a third lens 16, a first lens cylinder 18, a second lens cylinder 20, a moving cylinder 22, a fixed cylinder 24, a cam cylinder 26, and a diaphragm. It comprises a shutter unit 28 and the like.
[0013]
A gear portion 26a is formed on the outer periphery of the cam cylinder 26, and a driving force of a zoom motor (not shown) is transmitted to the gear portion 26a. The cam cylinder 26 is rotated by the driving force of the motor while contacting the outer periphery of the fixed cylinder 24 with the optical axis 30 as the rotation center.
[0014]
Further, the lens device 102 is moved from the retracted position to the tele position by rotating the cam cylinder 26 in the “storage rotation range” from the “initial position” to the “intermediate position”. Further, the cam cylinder 26 is moved from the tele position to the wide position by rotating in the “magnifying power range” from the “intermediate position” to the “end position”.
[0015]
A cam groove 26 b for moving the second lens cylinder 20 along the optical axis 30 and a rectilinear groove 26 c for moving the movable cylinder 22 along the optical axis 30 are formed on the inner peripheral surface of the cam cylinder 26. Is formed. The rectilinear groove 26 c transmits the rotational force of the cam cylinder 26 to the moving cylinder 22 via the cam follower 32.
[0016]
The fixed cylinder 24 is formed with a rectilinear groove 24 a that moves the second lens cylinder 20 along the optical axis 30 and a cam groove 24 b that moves the movable cylinder 22 along the optical axis 30.
[0017]
A cam follower 32 is provided on the outer peripheral surface of the moving cylinder 22. The cam follower 32 is fitted in the cam groove 24b, and is fitted in the rectilinear groove 26c through the cam groove 24b. Therefore, the moving cylinder 22 moves back and forth in the direction of the optical axis 30 with respect to the fixed cylinder 24 while rotating in conjunction with the rotation of the cam cylinder 26. A cam groove 22 a is formed on the inner peripheral surface of the movable cylinder 22. Note that the cam groove 24 b, the rectilinear groove 26 c, and the cam follower 32 are provided in three divided positions around the optical axis 30.
[0018]
The first lens 12 is held inside the first lens cylinder 18. Further, a rectilinear groove 34 is formed on the inner peripheral surface of the first lens cylinder 18, and a cam follower 36 that fits in the cam groove 22 a is provided on the outer peripheral surface of the first lens cylinder 18. Accordingly, the first lens cylinder 18 is optically guided with respect to the moving cylinder 22 by the rectilinear guide action (described later) by the second lens cylinder 20 and the feeding action of the cam groove 22a of the moving cylinder 22 by the rotation of the moving cylinder 22. Move back and forth in 30 directions. The cam follower 36 and the cam groove 22a are provided at three divided positions around the optical axis 30, respectively.
[0019]
A second lens 14 is held inside the second lens cylinder 20. A cam follower 38 is provided on the outer peripheral surface of the second lens cylinder 20. The cam follower 38 is fitted in the rectilinear groove 24a and the cam groove 26b. Therefore, the second lens cylinder 20 moves back and forth in the direction of the optical axis 30 with respect to the fixed cylinder 24 by the rotation of the cam cylinder 26. The cam follower 38, the cam groove 26b, and the rectilinear groove 24a are provided at three divided positions around the optical axis 30, respectively.
[0020]
Arm portions 50 and 50 are formed at the front end of the second lens barrel 20, and a rectilinear guide protrusion 52 is formed on the outer peripheral surface side of the tip of each arm portion 50. Since these rectilinear guide protrusions 52 are fitted in the rectilinear grooves 34 of the first lens cylinder 18, the rectilinear guide action described above is generated. Reference numeral 10a denotes an imaging plane of the lens device 102, and an imaging plane of a CCD (not shown) is disposed at this position.
[0021]
The third lens 16 is held by the third lens frame 40. The third lens frame 40 has a nut portion (not shown) screwed onto a screw shaft (not shown) of the feed screw device so that the third lens frame 40 moves back and forth in the direction of the optical axis 30, and light in the lens barrel 108. The second lens barrel 20 is supported via two guide shafts 42 and 44 arranged in parallel with the shaft 30.
[0022]
The screw shaft of the feed screw device is arranged in parallel with the optical axis 30 and is connected to an output shaft (not shown) of a focusing motor (not shown) built in the lens barrel 108, and a third lens. The nut 40 (not shown) of the frame 40 is screwed. Therefore, when the focus motor is driven, the third lens frame 40 moves back and forth in the direction of the optical axis 30 by the feed action of the feed screw device and the linear guide action of the guide shafts 42 and 44, and focusing by the third lens 16 is performed. Done.
[0023]
Incidentally, the guide shaft 42 shown in FIG. 2 includes a guide shaft main body portion 42A and a bearing portion 42B. The guide shaft main body 42 </ b> A is formed in a long shape and is inserted into a sleeve 41 formed on the third lens frame 40. Accordingly, the third lens frame 40 is slidably supported on the guide shaft 42 via the sleeve 41.
[0024]
The bearing portion 42B is integrally formed with the guide shaft main body portion 42A at both ends of the guide shaft main body portion 42A. The bearing portion 42B is formed to have a smaller diameter than the guide shaft main body portion 42A, and the center shaft 42b of the bearing portion 42B is located with respect to the central shaft 42a of the guide shaft main body portion 42A as shown in FIGS. It is formed at a fixed (s) eccentric position. As shown in FIG. 2, the bearing portions 42B and 42B are rotatably supported by the left bearing portion 42B in the hole 21A of the second lens barrel 20, and the right bearing portion 42B is supported by the second lens barrel 20. The attached stop plate 54 is rotatably supported in a hole 54A shown in FIG. A driver insertion groove 43 shown in FIG. 5 is formed on the end surface of the right bearing portion 42B.
[0025]
Therefore, when the tip of a driver (not shown) is inserted into the driver insertion groove 43 and the guide shaft 42 is rotated about the central axis 42b of the bearing portion 42B by the driver, the guide shaft main body portion 42A moves the central shaft 42b. Eccentric rotation about the center. By this eccentric rotation operation, the third lens frame 40 supported by the guide shaft main body portion 42A via the sleeve 41 is operated by the guide shaft main body portion 42A, and the arrow in FIG. It moves in a substantially vertical direction indicated by. This is because the third lens frame 40 is slidably supported by the guide shaft 44 via a horseshoe-shaped groove 40A formed in the vertical direction below the third lens frame 40. Therefore, the third lens frame 40 is rotated by the rotation of the guide shaft 42. The moving direction of 40 is only the substantially vertical direction defined by the horseshoe-shaped groove 40A. Thereby, the 3rd lens 16 moves to an up-down direction.
[0026]
On the other hand, the guide shaft 44 shown in FIG. 2 includes a guide shaft main body 44A and a bearing portion 44B. The guide shaft main body 44A is formed in a long shape, and a horseshoe-shaped groove 40A in FIG. 5 formed in the lower portion of the third lens frame 40 is slidably fitted therein.
[0027]
As shown in FIG. 6, the bearing portion 44B of the guide shaft 44 is formed integrally with the guide shaft main body 44A at both ends of the guide shaft main body 44A. The bearing portion 44B is formed to have a smaller diameter than the guide shaft main body portion 44A, and the center shaft 44b of the bearing portion 44B has a predetermined amount (s) relative to the central shaft 44a of the guide shaft main body portion 44A as shown in FIG. ) It is formed at an eccentric position. As shown in FIG. 2, the bearing portions 44B and 44B are supported such that the left bearing portion 44B is rotatably supported by the hole 21B of the second lens barrel 20, and the right bearing portion 42B is supported by the second lens barrel 20. The attached stopper plate 56 is rotatably supported in a hole 56A shown in FIG. A driver insertion groove 45 shown in FIG. 8 is formed on the end surface of the right bearing portion 44B.
[0028]
Therefore, when the tip of a driver (not shown) is inserted into the driver insertion groove 45 and the guide shaft 44 is rotated around the central axis 44b of the bearing portion 44B by the driver, the guide shaft main body 44A moves the central shaft 44b. Eccentric rotation about the center. By this eccentric rotation operation, the third lens frame 40 supported by the guide shaft main body portion 44A via the horseshoe-shaped groove 40A is operated by the guide shaft main body portion 44A, and within the plane orthogonal to the optical axis 30, FIG. Move in a substantially horizontal direction indicated by an arrow. This is because the third lens frame 40 swings about the center axis 42b of the bearing portion 42B of the guide shaft 42, and the third lens 16 moves in the horizontal direction by this swing.
[0029]
Thus, by appropriately rotating the guide shafts 42 and 44, the third lens 16 can be moved in the vertical and horizontal directions, so that the optical axis of the third lens 16 that has been shifted from the optical axis 30. O can be aligned with the optical axis 30.
[0030]
In the lens device 102 according to the embodiment, the guide shafts 42 and 44 are arranged in advance in parallel with the optical axis 30. Therefore, even if the guide shafts 42 and 44 are rotated, the central axes (bearings) The central axes 42b and 44b) of the portions 42B and 44B rotate while maintaining a parallel relationship with the optical axis 30. Therefore, even if the guide shafts 42 and 44 are rotated, the guide shafts 42 and 44 are not tilted. Therefore, it is only necessary to adjust the shaft misalignment, and the guide shafts 42 and 44 are rotated to perform the shaft misalignment adjustment. However, since the guide shafts 42 and 44 do not fall down, it is possible to prevent the slidability of the third lens frame 40 from being lowered with respect to the guide shafts 42 and 44.
[0031]
Furthermore, not only the two guide shafts 42 and 44 but also the lens frame is supported by three or more guide shafts, all the guide shafts are configured as the guide shafts 42 and 44 of the embodiment. As a result, the degree of freedom in the adjustment direction of the lens increases, and fine adjustment becomes possible.
[0032]
【The invention's effect】
As described above, according to the lens device of the present invention, when the guide shaft is rotated around the central axis of the bearing portion, the guide shaft main body portion rotates eccentrically around the central axis of the bearing portion. The lens frame supported by the main body is operated by the guide shaft main body, moves in a plane perpendicular to the optical axis, and the optical axis of the lens can be aligned. Further, according to the present invention, since the guide shaft does not fall even when the guide shaft is rotated, it is possible to prevent the slidability of the lens frame from being lowered with respect to the guide shaft. As described above, in the lens device of the present invention, the lens tilting and axis misalignment adjustment structures are improved, and the optical performance is improved.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electronic still camera to which a lens apparatus according to the present invention is applied. FIG. 2 is a sectional view of the lens apparatus shown in FIG. 1. FIG. 3 is a support structure for one guide shaft that supports a lens frame. FIG. 4 is a cross-sectional view of the guide shaft along line 4-4 in FIG. 3. FIG. 5 is an explanatory view showing the operation of the lens frame when the other guide shaft is rotated. FIG. 7 is a sectional view of the guide shaft taken along line 7-7 in FIG. 6. FIG. 8 is a view showing the operation of the lens frame when the other guide shaft is rotated. Explanatory drawing showing [signs]
DESCRIPTION OF SYMBOLS 12 ... 1st lens, 14 ... 2nd lens, 16 ... 3rd lens, 18 ... 1st lens cylinder, 20 ... 2nd lens cylinder, 22 ... Moving cylinder, 40 ... 3rd lens frame, 42, 44 ... Guide shaft , 42A, 44A ... guide shaft main body, 42B, 44B ... bearing, 100 ... electronic still camera, 102 ... lens device, 108 ... lens barrel

Claims (1)

In a lens apparatus in which a guide shaft is disposed in parallel with the optical axis in a lens barrel, and a lens frame is supported on the guide shaft,
The guide shaft includes a guide shaft main body portion on which the lens frame is supported, and a bearing portion that is formed at both ends of the guide shaft main body portion and has a central axis that is eccentric with respect to the central axis of the guide shaft main body portion. Consists of
The central axis of each bearing portion is coaxial,
A lens device, wherein each of the bearing portions is rotatably supported by the lens barrel so that the guide shaft main body portion rotates eccentrically around the central axis of the bearing portion .

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