JP4140235B2 - Lens device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens device used as a photographing lens of an imaging device such as a camera or a projection lens such as a projector.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been proposed a lens apparatus configured as a zoom lens that includes a plurality of lens groups and can change the focal length by moving some lens groups in the optical axis direction. As such a zoom lens, a so-called inner focus type zoom lens that consists of a fixed group and a moving group and changes the focal length and adjusts the focus by moving the moving group in the optical axis direction is proposed. Has been.
[0003]
Such an inner focus type zoom lens is configured as a high-magnification zoom lens, and is also suitable for constituting an imaging device such as a video camera or a so-called digital camera, which is reduced in size and improved in image quality. It is used as
[0004]
In such a lens device, in order to maintain the optical characteristics, the inclination of the optical axis may be adjusted during the manufacturing process for at least one lens. Then, as shown in FIG. 14, the lens barrel body 101 is moved with respect to the lens barrel main body 101 (a part of the lens barrel is omitted while others are omitted) so that the tilt adjustment of the optical axis can be performed. There has been proposed a lens apparatus configured by supporting one lens 103 to be adjusted by a movable frame 102 supported in a possible manner.
[0005]
In such a lens device, one lens 103 is fixed and held with respect to the movable frame 102 by means such as adhesion or heat caulking. The movable frame has a spherical outer peripheral surface portion, and is movable with respect to the barrel main body 101 in a state where the outer peripheral surface is in contact with the barrel main body 101. The spherical curvature center forming the outer peripheral surface portion of the movable frame 102 becomes a movable center point for adjusting the inclination of the optical axis of one lens 103.
[0006]
Note that, for example, three adjustment arms 104 protrude from the movable frame 102 on the outer peripheral surface portion. The inclination of the optical axis of the lens 103 held by the movable frame 102 is adjusted by moving the tip side portion of the adjusting arm 104 in the optical axis direction.
[0007]
[Problems to be solved by the invention]
By the way, in the lens device as described above, the lens 103 that is capable of adjusting the inclination of the optical axis has a movable frame 102 interposed between the lens body 101 and the lens body 101. On the other hand, positioning is performed via the movable frame 102. That is, the lens 103 is as much as the assembly error between the lens 10 and the movable frame 102 and the shape error of the movable frame 102 compared to the case where the lens 103 is positioned in direct contact with the lens barrel main body 101. Position accuracy will be inferior.
[0008]
Moreover, since the movable frame 102 has a complicated shape, it is often made of a resin mold. It is difficult to increase the rigidity of the movable frame 102 that is a resin mold part, and there is a possibility that the lens 103 may be slightly deformed by a load for holding the lens 103. The position accuracy of the center position of the lens 103 may deteriorate due to such bending of the movable frame 102.
[0009]
Therefore, the present invention is proposed in view of the above-described circumstances, and is a lens device including a plurality of lenses including at least one lens that is capable of adjusting the inclination of the optical axis, It is an object of the present invention to provide a lens device in which a single lens can be positioned with high accuracy.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, a lens device according to the present invention is configured by housing a plurality of lenses in a lens barrel body, and at least one of the plurality of lenses has an optical axis tilt adjustment. A lens device made possible, comprising a frame-like movable frame disposed in the lens barrel main body so as to be movable with respect to the lens barrel main body, and holding an outer peripheral portion of one lens, The movable frame has at least three cutout portions that allow the outer peripheral surface portion of the one lens to face the lens barrel main body portion, and the one lens has at least 3 of the outer peripheral surface portion that faces the cutout portion. a portion being in contact against the lens barrel body, characterized in that the movement in the direction of tilting the optical axis is supported is possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
In this embodiment, the lens device according to the present invention is configured as a zoom lens including four lens groups. As shown in FIG. 1, the zoom lens includes a first lens group 1, which is a positive power fixed group having a rotation mechanism around the X axis and the Y axis with the optical axis as the Z axis, zooming (magnification operation) Negative power second lens group 2 which is a moving group for the third lens group, third lens group 3 which is a positive power fixed group having rotation mechanisms around the X axis and the Y axis, and focusing (focus adjustment operation) And a fourth lens group 4 which is a positive power moving group. That is, in this zoom lens, the first lens group 1 and the third lens group 3 are lenses capable of adjusting the inclination of the optical axis.
[0013]
In this zoom lens, the lens 5 forming the third lens group 3 is fixed to the movable frame 6 by means such as adhesion or thermal caulking as shown in FIG. 2, and as shown in FIG. 6 and is integrated with the movable frame 6. As shown in FIG. 4, the lens 5 is fitted and positioned with respect to the movable frame 6 at the outer peripheral surface portion of the lens 5 and the peripheral portion of the front surface of the lens 5.
[0014]
As shown in FIGS. 2 and 3, the movable frame 6 has notches 7 formed at four locations corresponding to the outer peripheral surface of the lens 5. From these notches 7, a part 5 a of the outer peripheral surface of the lens 5 faces the outer side of the movable frame 6. These cutout portions 7 are not limited to four locations as long as at least three portions of the outer peripheral surface portion of lens 5 face outward, and are generated at three locations or five or more locations. Also good.
[0015]
As shown in FIG. 5, the movable frame 6 holding the lens 5 is incorporated in a barrel main body 8 (a part of the barrel is cut off and the others are omitted). At this time, as shown in FIG. 6, the movable frame 6 is inserted into and supported by the fitting hole 9 provided in the lens barrel main body portion 8. As shown in FIG. 5, a plurality of protrusions 10 corresponding to the notches 7 of the movable frame 6 are formed on the inner peripheral edge of the fitting hole 9. When the movable frame 6 is inserted into the fitting hole 9, as shown in FIG. 7, a part 5 a of the outer peripheral surface portion of the lens 5 that faces outward through the notch portion 7 has a lens barrel main body portion. Each protrusion 10 which is a part of 8 abuts. That is, at this time, as shown in FIGS. 8 and 9, which are cross-sectional views taken along the line BB in FIG. 6, the lens 5 is in a state of being fitted in the respective protruding portions 10. Thus, positioning is performed in the coordinate X direction and the coordinate Y direction shown in FIG. The contact between the lens 5 and each projection 10 of the lens barrel main body 8 may be made at least at three locations on the outer peripheral surface of the lens 5. The protrusions 10 come into contact with at least three locations on the outer peripheral surface portion of the lens 5, thereby restricting movement of the lens 5 in the direction (X direction and Y direction) perpendicular to the optical axis (Z axis) with respect to the lens barrel main body portion 8. Then, the lens 5 is positioned with respect to the lens barrel body 8.
[0016]
As shown in FIG. 7, the outer peripheral surface portion of the lens 5 is processed into a spherical shape centering on the movable center point 11 for adjusting the inclination of the optical axis of the lens 5. Rotation around the X axis, rotation around the Y axis, rotation around the Z axis, and movement in the Z axis (optical axis) direction (movement in the four directions of arrows θx, θy, θz, and Z shown in FIG. 5). It is possible.
[0017]
As shown in FIG. 10, even if the outer peripheral surface portion of the lens 5 is cylindrical, the outer peripheral surface portion indicated by t in FIG. 10 contacts the protruding portion 10 by providing the chamfered portion 12 on the outer peripheral surface portion. If the width is made sufficiently narrow, the rotation around the X axis and the rotation around the Y axis can be adjusted in the same manner as in the case where the outer peripheral surface portion is a spherical surface within a very small angle range.
[0018]
As shown in FIG. 5, a columnar protrusion 12 is formed on the movable frame 6 in the Y-axis direction orthogonal to the optical axis (Z-axis). The protrusion 12 is inserted into a groove 13 provided in the lens barrel main body 8. The groove 13 is formed as a portion between the two protrusions 10 and 10. The protrusion 12 is perpendicular to the optical axis (Z axis) and parallel to the Y axis, as shown in FIG. 11 which is a CC sectional view in FIG. 4 which is an AA sectional view in FIG. In addition, the lens 5 is formed in a shape that forms a part of a cylinder whose central axis is a straight line passing through the movable center point 11 for adjusting the inclination of the optical axis of the lens 5. The groove portion 13 has a shape that restricts movement of the protrusion 12 in the X-axis direction and does not restrict movement in the Z-axis direction. Therefore, the movable frame 6 is restricted from rotating around the optical axis (Z axis), and is moved around the X axis, the Y axis, and the Z axis (optical axis) (indicated by arrows θx, θy, and Z shown in FIG. 5). Only movement in three directions is possible.
[0019]
The movable frame 6 is provided with three arm portions 14, 15, and 16 as shown in FIGS. If the position in the optical axis direction of these three arm portions 14, 15, 16 is adjusted by any means in the lens barrel main body portion 8, the lens axis is rotated around the X axis and the Y axis, that is, the optical axis of the lens 5. Tilt adjustment can be performed arbitrarily. For example, as shown in FIG. 12 and FIG. 13 which is a DD cross-sectional view in FIG. 12, the movable frame 6 is disposed so that the ring-shaped leaf spring 20 is overlapped on the movable frame 6. The movement in the direction of the optical axis (Z-axis) is restricted by pressing to the main body 8 side, and the female screw 17 is screwed into the screw hole 18 provided in the barrel main body 8 as shown in FIGS. The distal end portion of the female screw 17 is brought into contact with a tapered portion 19 provided on the distal end side of the arm portion 16.
[0020]
The leaf spring 20 has four (or three) bulging portions 21 toward the movable frame 6 for making point contact with the movable frame 6 at four points (or three points). Is formed. The leaf spring 20 is attached to the lens barrel main body 8 with the outer peripheral edge portion held by a plurality of spring hooking pieces 22 provided on the lens barrel main body 8.
[0021]
In this configuration, the position of the arm portion 16 in the optical axis direction can be adjusted by the screwing amount of the tube screw 17 into the barrel main body portion 8. Various means and configurations for moving the arm portions 14, 15, and 16 in the direction of the optical axis are conceivable and not particularly limited.
[0022]
In addition, when the rotation of the movable frame 6 around the Z axis can be restricted by the frictional force between the arm portions 14, 15, 16 and the portions that support the arm portions 14, 15, 16, or the arm portions 14, 15 , 16 is provided with a flange portion, and even if the movable frame 6 rotates around the Z axis, the rotation position around the X axis and the Y axis does not change, the projection 12 and the groove portion 13 described above. It is not necessary to regulate the rotation of the movable frame 6 around the Z axis.
[0023]
【The invention's effect】
As described above, in the lens apparatus according to the present invention, the lens that is the target of the optical axis tilt adjustment is positioned in direct contact with the lens barrel main body, and thus is orthogonal to the optical axis of the lens. Directional positioning can be performed with high accuracy.
[0024]
Therefore, even if the precision and rigidity of the movable frame that holds the lens are lowered, the lens can be positioned with higher accuracy than in the conventional lens device, making the manufacturing easier, reducing the manufacturing cost, and moving the lens. It is possible to reduce the size and weight by reducing the thickness of the frame.
[0025]
That is, the present invention is a lens device including a plurality of lenses including at least one lens in which the inclination of the optical axis can be adjusted, and the lens capable of positioning the one lens with high accuracy. An apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a side view showing a configuration of a lens apparatus according to the present invention.
FIG. 2 is an exploded perspective view illustrating a configuration of a lens that is an object of tilt adjustment of an optical axis and a movable frame that holds the lens in the lens device.
FIG. 3 is a perspective view showing a state where the lens is held by the movable frame.
4 is a longitudinal sectional view corresponding to the AA sectional view in FIG. 6 showing a state in which the lens is held by the movable frame and disposed in the barrel main body.
FIG. 5 is an exploded perspective view showing a state in which the lens is held in the movable frame and disposed in the barrel main body.
FIG. 6 is a front view showing a state in which the lens is held in the movable frame and arranged in the barrel main body.
FIG. 7 is a longitudinal sectional view showing a configuration of a main part when the lens is held by the movable frame and disposed in the barrel main body.
8 is a vertical cross-sectional view corresponding to a cross-sectional view taken along the line BB in FIG. 6 showing a state where the lens is held by the movable frame and disposed in the barrel main body.
FIG. 9 is a rear view showing a state in which the lens is held in the movable frame and disposed in the barrel main body.
FIG. 10 is a longitudinal sectional view showing another example of the configuration of the main part when the lens is held by the movable frame and disposed in the barrel main body.
11 is a cross-sectional view corresponding to a cross-sectional view taken along a line CC in FIG. 4 showing a configuration of a main part when the lens is held by the movable frame and disposed in the barrel main body.
FIG. 12 is a front view showing a state in which the lens is held by the movable frame and disposed in the barrel main body and pressed by a leaf spring.
13 is a longitudinal sectional view corresponding to a DD sectional view in FIG. 12 showing a state in which the lens is held by the movable frame and disposed in the barrel main body and pressed by a leaf spring.
FIG. 14 is a longitudinal sectional view showing a configuration of a main part of a conventional lens device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st lens group, 2nd 2nd lens group, 3rd 3rd lens group, 4th 4th lens group, 5 lens, 6 movable frame, 7 notch part, 8 lens barrel main-body part, 9 fitting hole, 10 protrusion part , 11 Movable center point for adjusting the tilt of the optical axis, 12 protrusions, 13 grooves, 14, 15, 16 arm, 17 grommet

Claims (4)

A plurality of lenses housed in a lens barrel body, and at least one of the plurality of lenses is a lens device capable of adjusting an optical axis inclination;
In the lens barrel main body, a frame-shaped movable frame that is disposed so as to be movable with respect to the lens barrel main body and holds an outer peripheral portion of one lens,
The movable frame has at least three notches that allow the outer peripheral surface of the one lens to face the lens barrel body.
The one lens, at least three of the outer peripheral surface portion to face from the notch while being contact with the lens barrel body is supported is allowed to move in the direction of tilting the optical axis A lens device.   2. The lens apparatus according to claim 1, wherein the one lens has a spherical shape with an outer peripheral surface portion having a center of curvature at a movable center point in adjusting the inclination of the optical axis.   The movable frame has a cylindrical protrusion on the outer peripheral portion that is perpendicular to the optical axis of the one lens and that has a straight line passing through the movable center point in adjusting the tilt of the optical axis of the one lens as a central axis. 2. The lens apparatus according to claim 1, wherein the protrusion is inserted into a groove provided in the lens barrel main body in a direction along the optical axis.   The lens apparatus according to claim 1, wherein the lens apparatus is configured as a four-group zoom lens, and the optical axis inclination of the third group lens can be adjusted.

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