JP2003185899A - Lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately position a lens in the case that the inclination of the optical axis of at least the one lens out of several lenses is adjusted. <P>SOLUTION: The lens 5 to be adjusted is supported so as to be movable in a direction in which the optical axis is inclined while at least three points of an outer peripheral surface part are brought into contact with a lens barrel main body 8. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens device used as a photographing lens of an image pickup device such as a camera or a projection lens of a projector.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a lens device composed of a plurality of lens groups, which is configured as a zoom lens capable of changing a focal length by moving a part of the lens groups in the optical axis direction. Further, as such a zoom lens, a so-called inner focus type zoom lens is proposed which is composed of a fixed group and a movable group, and changes the focal length and adjusts the focus by moving the movable group in the optical axis direction. Has been done.

Such an inner focus type zoom lens is constructed as a high-magnification zoom lens, and is downsized and has high image quality, and is suitable for constituting an image pickup device such as a video camera or a so-called digital camera. Used as a simple zoom lens.

In such a lens device, in order to maintain the optical characteristics, at least one lens is
The tilt of the optical axis may be adjusted during the manufacturing process.
Then, in order to adjust the inclination of the optical axis as described above, 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 cut into a circle and the other is omitted). A lens device has been proposed in which a movable frame 102 supported as much as possible supports one lens 103 to be adjusted.

In such a lens device, one lens 103 is fixed and held to the movable frame 102 by means such as adhesion or heat caulking. The movable frame is
The outer peripheral surface portion has a spherical shape and is movable with respect to the lens barrel body portion 101 in a state where the outer peripheral surface portion is in contact with the lens barrel body portion 101. This movable frame 10
The center of curvature of the spherical shape forming the outer peripheral surface 2 of FIG. 2 becomes the movable center point for adjusting the inclination of the optical axis of the one lens 103.

Incidentally, the movable frame 102 is provided with, for example, three adjusting arms 104 projecting from the outer peripheral surface thereof. By moving the tip end side portions of these adjustment arms 104 in the optical axis direction, the lens 10 held by the movable frame 102 is moved.
The tilt adjustment of the optical axis 3 is performed.

[0007]

By the way, in the lens device as described above, the movable frame 1 is provided between the lens 103 and the lens barrel body 101 in which the tilt of the optical axis can be adjusted.
Since 02 is interposed, the lens barrel body 101 is positioned via the movable frame 102. That is, this lens 103 is
As compared with the case where the lens 10 and the movable frame 102 are directly contacted with each other for positioning, the positional accuracy is deteriorated by the assembly error between the lens 10 and the movable frame 102 and the shape error of the movable frame 102.

Since the movable frame 102 has a complicated shape, it is often formed by resin molding. It is difficult to increase the rigidity of the movable frame 102, which is a resin-molded component, and there is a possibility that the movable frame 102 may be slightly deformed by the load for holding the lens 103. Such bending of the movable frame 102 may also deteriorate the positional accuracy of the central position of the lens 103.

Therefore, the present invention is proposed in view of the above situation, and is a lens device composed of a plurality of lenses including at least one lens capable of adjusting the tilt of the optical axis. Therefore, the present invention is intended to provide a lens device capable of highly accurately positioning the one lens.

[0010]

In order to solve the above-mentioned problems, a lens device according to the present invention is constructed such that a plurality of lenses are housed in a lens barrel body, and at least one of the plurality of lenses is a lens. Is a lens device in which the tilt of the optical axis can be adjusted, and the one lens is configured so that the optical axis is tilted in a state where at least three positions of the outer peripheral surface portion are in contact with the lens barrel body. It is characterized in that it is movable and supported.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the lens apparatus according to the present invention is configured as a zoom lens composed of four lens groups. As shown in FIG. 1, this zoom lens includes a first lens group 1 which is a fixed group of positive power and has a rotating mechanism around the X axis and the Y axis with the optical axis as the Z axis, and zooming (variable magnification operation). Of the second lens group 2 of negative power, which is a moving group for, and the third lens group 3 of a fixed group of positive power, which has a rotating mechanism about the X axis and the Y axis, and focusing (focus adjustment operation). The fourth lens group 4 which is a moving group of positive power for That is, in this zoom lens, the first lens group 1 and the third lens group 3 are lenses capable of adjusting the tilt of the optical axis.

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 heat caulking as shown in FIG. 2, and as shown in FIG. It is held by the movable frame 6 and integrated with the movable frame 6. As shown in FIG. 4, the lens 5 is fitted and positioned in the outer peripheral surface portion of the lens 5 and the peripheral portion of the front surface of the lens 5 with respect to the movable frame 6.

As shown in FIGS. 2 and 3, the movable frame 6 is provided with notches 7 at four positions corresponding to the outer peripheral surface of the lens 5. A part 5 a of the outer peripheral surface of the lens 5 faces the outer side of the movable frame 6 from these cutouts 7. These cutouts 7 are not limited to four, as long as at least three of the outer peripheral surface of the lens 5 are exposed to the outside, and two, three,
Alternatively, it may be generated at five or more locations.

As shown in FIG. 5, the movable frame 6 holding the lens 5 is incorporated in a lens barrel main body 8 (a part of the lens barrel is cut into a ring and the other is omitted). At this time, as shown in FIG. 6, the movable frame 6 is inserted into and supported by a fitting hole 9 provided in the lens barrel body 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. Each protrusion 10, which is a part of 8, contacts. That is, at this time, the lens 5
As shown in FIGS. 8 and 9 which are sectional views taken along the line BB in FIG. 6, each of the protrusions 10 is fitted in a state of being inscribed, and these protrusions 10 are shown in FIG. Positioning is performed in the coordinate X direction and the coordinate Y direction. The contact between the lens 5 and each protrusion 10 of the lens barrel body 8 may be made at least at three positions on the outer peripheral surface of the lens 5. The protrusions 10 contact at least three positions on the outer peripheral surface of the lens 5 to restrict movement of the lens 5 with respect to the lens barrel body 8 in directions (X and Y directions) orthogonal to the optical axis (Z axis). Then, the lens 5 is positioned with respect to the lens barrel body 8.

As shown in FIG. 7, the outer peripheral surface of the lens 5 is formed into a spherical shape centered on a movable center point 11 for adjusting the tilt of the optical axis of the lens 5, and is inscribed in each projection 10. In the state, rotation around the X axis, rotation around the Y axis,
It is possible to rotate around the Z axis and move in the Z axis (optical axis) direction (movement in four directions of arrows θx, θy, θz, and Z shown in FIG. 5).

As shown in FIG. 10, even if the outer peripheral surface of the lens 5 has a cylindrical shape, by providing the chamfered portion 12 on the outer peripheral surface, the outer peripheral surface indicated by t in FIG. If the width of the contact with the slab is sufficiently narrowed, the rotation about the X axis and the rotation about the Y axis can be adjusted within the minute angular range in the same manner as when the outer peripheral surface portion is a spherical surface. .

As shown in FIG. 5, the movable frame 6 is provided with columnar protrusions 12 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 body 8. This groove portion 13 is formed as a portion between the two protruding portions 10, 10. The protrusion 12 is orthogonal to the optical axis (Z axis) and parallel to the Y axis as shown in FIG. 11 which is a sectional view taken along the line CC of FIG. 4 which is a sectional view taken along the line AA of FIG. In addition, the lens 5 is formed in a shape that forms a part of a cylinder whose center 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 arm portion 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 about the optical axis (Z axis), moves about the X axis, about the Y axis, and moves in the Z axis (optical axis) direction (indicated by arrows θx, θy, and Z shown in FIG. 5). Only movement in three directions) is possible.

The movable frame 6 is provided with three arm portions 14, 15 and 16 as shown in FIGS. If the positions of these three arm portions 14, 15, 16 in the optical axis direction are adjusted by some means in the lens barrel body portion 8, the lens can be rotated about the X axis and the Y axis, that is, the optical axis of the lens 5. It is possible to arbitrarily adjust the inclination. For example, as shown in FIG. 12 and FIG. 13 which is a cross-sectional view taken along the line D-D in FIG. 12, the movable frame 6 is arranged so that the ring-shaped leaf spring 20 is superposed on the movable frame 6 to thereby dispose the lens barrel. The movement in the optical axis (Z-axis) direction is regulated by pressing it toward the body portion 8 side, and as shown in FIGS. The tip portion of the set screw 17 is brought into contact with the taper portion 19 provided on the tip side of the arm portion 16.

It should be noted that the leaf spring 20 has 4
There are four bulging portions 21 (or three points) facing the movable frame 6 for making substantially point contact at the points (or three points).
Formed). Further, the leaf spring 20 is attached to the lens barrel main body 8 by holding the outer peripheral edge portion thereof by a plurality of spring locking pieces 22 provided on the lens barrel main body 8.

In this structure, the position of the arm portion 16 in the optical axis direction can be adjusted by the screwing amount of the set screw 17 into the lens barrel body portion 8. As described above, various means and configurations for moving and operating the arm portions 14, 15, 16 in the optical axis direction are conceivable, and are not particularly limited.

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 supporting the arm portions 14, 15, 16, or In the case where a flange portion is provided in place of 14, 15, 16 and the movable frame 6 has a structure in which the rotational position around the X axis and the Y axis does not change even when the movable frame 6 rotates around the Z axis, the above-described protrusion 12 and Movable frame 6 by the groove portion 13
It is not necessary to regulate the rotation around the Z axis.

[0023]

As described above, in the lens device according to the present invention, since the lens for which the tilt of the optical axis is adjusted is positioned in direct contact with the lens barrel body,
Positioning of the lens in the direction orthogonal to the optical axis can be performed with high accuracy.

Therefore, even if the precision and rigidity of the movable frame for holding the lens is reduced, the lens can be positioned with higher precision than in the conventional lens device.
The manufacturing can be facilitated, the manufacturing cost can be reduced, and the movable frame can be reduced in thickness to be reduced in size and weight.

That is, the present invention is a lens device constituted by a plurality of lenses including at least one lens whose optical axis tilt can be adjusted, and enables highly accurate positioning of the one lens. It is possible to provide the made lens device.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a lens device according to the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a lens to be an optical axis tilt adjustment target and a movable frame holding the lens in the lens device.

FIG. 3 is a perspective view showing a state where the lens is held by the movable frame.

FIG. 4 is a vertical cross-sectional view corresponding to a cross-sectional view taken along the line AA in FIG. 6, showing a state in which the lens is held by the movable frame and arranged in the barrel main body portion.

FIG. 5 is an exploded perspective view showing a state in which the lens is held by the movable frame and is arranged in the lens barrel body.

FIG. 6 is a front view showing a state in which the lens is held by the movable frame and arranged in a lens barrel main body portion.

FIG. 7 is a vertical cross-sectional view showing a configuration of a main part when the lens is held by the movable frame and arranged in a lens barrel body.

FIG. 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 arranged in the lens barrel main body.

FIG. 9 is a rear view showing a state in which the lens is held by the movable frame and arranged in the lens barrel body.

FIG. 10 is a vertical cross-sectional view showing another example of the configuration of the main part when the lens is held by the movable frame and arranged in the lens barrel body.

FIG. 11 is a C in FIG. 4 showing a configuration of a main part when the lens is held by the movable frame and arranged in the lens barrel body.
It is a cross-sectional view corresponding to the -C cross-sectional view.

FIG. 12 is a front view showing a state in which the lens is held by the movable frame, arranged inside the barrel main body, and pressed by a leaf spring.

13 is a vertical cross-sectional view corresponding to a DD cross-sectional view in FIG. 12, showing a state in which the lens is held by the movable frame, is disposed inside the barrel main body, and is pressed by a leaf spring.

FIG. 14 is a vertical cross-sectional view showing a configuration of a main part of a conventional lens device.

[Explanation of symbols]

1 1st lens group, 2 2nd lens group, 3 3rd lens group, 4 4th lens group, 5 lenses, 6 movable frames, 7
Notch, 8 barrel body, 9 fitting hole, 10 protrusion,
11 Movable center point for tilt adjustment of optical axis, 12 protrusions, 13
Grooves, 14, 15, 16 Arms, 17 Set screws

Claims (6)

[Claims] 1. A lens device in which a plurality of lenses are housed in a lens barrel main body, and at least one of the plurality of lenses is capable of adjusting an inclination of an optical axis, The one lens is capable of moving in a direction in which the optical axis is tilted and supported in a state where at least three positions of the outer peripheral surface are in contact with the lens barrel main body. 2. The lens device according to claim 1, wherein the outer peripheral surface of the one lens has a spherical shape having a center of curvature as a center of curvature in adjusting the inclination of the optical axis. 3. The lens according to claim 1, wherein the width of the outer peripheral surface portion in contact with the lens barrel body is such that the inclination of the optical axis can be adjusted while the outer peripheral surface portion is in contact with the lens barrel body. The lens apparatus according to claim 1, wherein the lens apparatus is a lens apparatus. 4. A frame-shaped movable frame, which is disposed in the lens barrel body so as to be movable with respect to the lens barrel body and holds an outer peripheral portion of one lens, wherein the movable frame is At least two notched portions that expose the outer peripheral surface of the lens to the inside of the lens barrel body,
2. The lens device according to claim 1, wherein an outer peripheral surface portion of the one lens exposed from the cutout portion is in contact with the lens barrel body. 5. The movable frame is provided with a cylindrical protrusion on the outer peripheral portion whose center axis is a straight line which is perpendicular to the optical axis of one lens and which passes through the movable center point in tilt adjustment of the optical axis of this one lens. 5. The lens apparatus according to claim 4, wherein the projection is inserted into a groove provided in the lens barrel main body in a direction along the optical axis. 6. A fourth group zoom lens constructed as a third lens group.
The lens device according to claim 1, wherein the tilt of the optical axis of the group lens can be adjusted.