JP2002267919A - Twin lena barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twin lens barrel which can prevent a cam ring from deviating in the optical axis direction and slanting from the optical axis direction in a twin lens barrel which move moving lean groups in right and left objective optical systems at the same time. SOLUTION: A zoom lens barrel 2 comprises a fixed right 3 which has a rectilinear groove 3e and holds 1st and 4th lens groups 221 and 231, and 224 and 234 of the respective zoom optical systems 220 and 230, the cam ring 4 which are held in the fixed ring 3 only rotatably and has cam grooves 4a and 4b for the two systems, 2nd and 3rd lens frames 5 and 6 which are fitted in the cam groove 4 and both hold 2nd and 3rd lens groups 222 and 232, and 223 and 233 of the zoom optical systems 220 and 230, cam followers 10 and 11 which are implanted in the outer peripheral surfaces of the leans frames 5 and 6 and inserted into the intersections of the rectilinear groove 3e and one of the cam grooves 4a and 4b, and a tension spring 18 which energizes the 3rd lens frame toward the bottom 3a of the fixed ring 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binocular lens barrel for holding a moving lens group in a pair of objective optical systems arranged at a predetermined base line distance.

[0002]

2. Description of the Related Art An objective optical system of this kind is used as a part of a binocular optical system such as binoculars, a stereo microscope, and a stereo camera.

When a focusing lens (compensator lens) for adjusting the focus and a variable power lens (zoom lens) for changing the magnification are incorporated in the pair of objective optical systems, these lenses are moved and adjusted along the optical axis. Since it must be possible, the moving lens of each objective optical system needs to be housed in a lens barrel composed of a lens frame, a cam ring, and a fixed ring. However, if the moving lens groups of the pair of left and right objective optical systems are moved independently of each other, the magnification and the focus of the left and right images may be deviated. A zoom lens barrel fixed to a frame and moving the lens frame in the direction of the optical axis so that the left and right objective optical systems can be simultaneously enlarged or reduced by the same amount or focused. Have been proposed.

[0004] The applicant of the present invention has previously described an example of a lens barrel (zoom barrel) in which a pair of left and right objective optical systems (zoom optical systems) has a plurality of moving lens groups.
No. 5085. This patent application 2000-38
FIG. 11 shows a configuration in which the invention according to No. 5085 is further embodied.
13 to FIG.

[0005] A pair of left and right objective optical systems shown in each of these figures has four lens groups 411 including second lens groups (magnifying lenses) 412, 422 and third lens groups (focusing lenses) 413, 423. ~ 414, 421-424,
The optical axes Ax ′ and Ax ″ are arranged so as to be parallel to each other while being separated by a predetermined base line length. Among them, the first and fourth lens groups 411, 421, 414 and 424 are fixed. The configuration of the lens barrel 400 that enables the second lens group 412, 422 and the third lens group 413, 423 to move in the optical axis direction is, in short, a cylindrical fixed ring 401 with a bottom. The cam ring 402 is freely rotatably fitted into the cam ring 402, and the second and third lens frames 403, 4 having a flat bottomed cylindrical shape are inserted into the cam ring 402.
04 is movably inserted in the direction of the central axis, and a disc-shaped lid 401a is inserted into the open end of the fixed ring 401. In addition, an annular gear 402 a having teeth formed on the inner periphery is fitted and fixed to the lower end of the inner peripheral surface of the cam ring 402. The annular gear 15 has a fixed ring 4
The pinion 406a attached to the drive shaft of the motor 406 fixed to the bottom 401b of the motor 01 is engaged. Further, a straight through groove (straight-moving groove) parallel to the center axis is formed in the cylindrical surface of the fixed ring 401, and a pair of cams oblique to the center axis are formed in the cylindrical surface of the cam ring 402. Grooves are formed, and cam pins 403a and 404a implanted on the outer peripheral surfaces of the second and third lens frames 403 and 404 respectively penetrate the intersections between the respective cam grooves and the rectilinear grooves.

With such a configuration, when the motor 406 rotates the cam ring 402 in an arbitrary rotation direction via the cam ring drive gear 402a, the intersections between the cam grooves and the rectilinear grooves move in the optical axis direction, respectively. As the intersections move in the optical axis direction, the second and third lens frames 403 and 404 move in the optical axis direction. At this time, the second and third lens frames 40
3, 404 move while maintaining the orientation in the base line length direction, so that the second and third lens groups 412, 422, 413,
423 will move along each optical axis. Thus, the second lens group 41 is formed by the second lens frame 403.
As a result, the left and right images finally formed via these objective optical systems are simultaneously enlarged or reduced by the same amount. Further, as a result of the third lens group 413 and 423 being simultaneously moved by the third lens frame 403, the left and right images finally formed through these objective optical systems are simultaneously focused, and these left and right images are simultaneously focused. There is no left and right out-of-focus in the image stereoscopically viewed based on.

A tension spring 405 is provided between the two lens frames 403 and 404 so as to rotate each other around the center axis of the cam ring 402 and to apply a biasing force in a direction to draw each other in the optical axis direction. It is hooked at an angle to the central axis. Therefore, the cam pins 403a,
Since the 404a is always pressed against one side edge of the cam groove and one side edge of the rectilinear groove, the clearance 404a is smaller than the width of the cam groove and the rectilinear groove. With cam pins 403a, 4
The problem of so-called backlash in which the position of 04a is not determined has been solved.

[0008]

The lens barrel 4 described above
00, the lid 401a of the fixed ring 401 and the cam ring 402
Between the bottom of the fixed ring 401 and the cam ring 40.
2, there must be some clearance between the inner peripheral surface of the cylinder of the fixed ring 401 and the outer peripheral surface of the cylinder of the cam ring 402.

However, when the amount of such clearance is large, when gravity is applied to the cam ring 402 in various directions by inclining the lens barrel 400 in various directions during observation of the subject, the fixed ring 401 A problem arises that the relative position of the cam ring 402 with respect to is not determined.

In this case, since the center axis of the cam ring 402 is inclined with respect to the center axis of the fixed ring 401 or the cam ring 402 moves in the center axis direction in accordance with the direction in which the lens barrel 400 is turned, the second And the third lens groups 412, 422, 41
In some cases, the left and right images move or the focus position is shifted due to the inclination of the optical axis 3423 with respect to the optical axis of the objective optical system. In particular, when the magnification is high, the movement and out-of-focus of the image become remarkable.

In this case, when the cam ring 402 is rotated by the motor 406 in order to move the second and third lens frames 403 and 404 in the optical axis direction, the driving force of the motor 406 is reduced. , The cam ring 402 is inclined in accordance with the direction in which the driving force is applied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a cylindrical lens for moving a part of lens groups constituting a pair of right and left objective optical systems in synchronization with each other. Despite the configuration in which the lens frame is moved in the central axis direction by rotating the cylindrical cam ring with respect to the fixed ring of the shape, even when a large clearance is taken between the fixed ring and the cam ring, An object of the present invention is to provide a binocular lens barrel capable of restricting the movement of the cam ring in the optical axis direction within the range and suppressing the cam ring from falling in the optical axis direction.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an objective optical system having a pair of objective optical systems for forming images of the same object from positions separated by a predetermined base line length. A binocular lens barrel for holding a moving lens group, comprising a cylindrical member having a central axis parallel to an optical axis of each of the objective optical systems, and a fixed groove formed with a rectilinear groove parallel to the central axis. A ring and a cylindrical member having a center axis parallel to the optical axis are formed so as to be freely rotatably fitted to the fixed ring, and have a cam groove having a portion inclined with respect to the center axis. And a lens frame that is held movably only in a direction parallel to the optical axis inside the fixed ring and the cam ring, and that holds the moving lens groups in both the objective optical systems together. Attached to this lens frame A cam follower extending through the intersection of the Rutotomoni the straight groove and the cam groove, in that the lens frame and a biasing member for urging the end portion of the fixed ring, characterized.

With this configuration, since the lens frame is urged to the end of the fixed ring by the urging member, the lens frame held in the cam ring via the cam follower and the cam groove is formed by the cam frame. Press the ring against the end of the stationary ring. As a result, the cam ring included in the fixed ring with a predetermined clearance always comes into contact with the fixed ring at a fixed position, so that the cam ring moves in the optical axis direction or tilts with respect to the optical axis direction. There is no. Therefore, a pair of movable lens groups held in the cam ring via the lens frame may be displaced in the focus position due to the movement of the cam ring in the optical axis direction, or may be a movable lens group by the cam ring being inclined from the optical axis direction. The image does not move due to the group falling down.

In the present invention, the moving lens group may be a focusing lens or a variable power lens. In other words, the moving lens group needs to be moved by the same amount on the left and right simultaneously. The moving lens groups are all targeted. The urging member may be a tension spring or rubber.

Either of the cam ring and the fixed ring may be inside as long as they fit each other. In this case, the groove formed on the inner side must be a through groove, but the groove formed on the outer side is a through groove even if it is a bottomed groove drilled from the inside. Is also good. The rectilinear groove, the cam groove and the cam follower may be only one set as long as the lens frame is guided in the optical axis direction without play. However, if a plurality of sets surround the center of the lens frame, eccentricity of the lens group is prevented. Preferred above. In particular, it is desirable to be provided at equal angular intervals in the circumferential direction of the fixed ring and the cam ring.

When there are a plurality of lens frames, it is desirable to provide a second biasing member between the lens frames and to attract each other. The number of the second urging members may be only one, or may be plural.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

[0019]

[Embodiment 1] A binocular lens barrel according to a first embodiment described below is incorporated in, for example, a video stereo microscope constituting a surgery support system used in neurosurgery. This surgery support system displays a stereoscopic image (stereo image) obtained by video-taking a patient's tissue with a stereoscopic microscope on a stereoscopic viewer dedicated to the operator or a monitor for other staff, and also records the image. This is a system for recording on the device.

(Overall Configuration of Surgery Support System) FIG.
It is a system configuration diagram showing an outline of this surgery support system. As shown in FIG. 1, the surgery support system
A stereo microscope 101 and a high-vision CCD camera 10 attached near the upper end of the back of the stereo microscope 101
2, a counterweight 104 attached to the upper surface of the stereo microscope 101, and the counterweight 104
A light guide fiber bundle 105 penetrated through the through-hole opened in the stereoscopic microscope 101 and
A light source device 106 for introducing illumination light to the stereo microscope 101 through the light guide fiber bundle 105 and a distributor 11 connected to the high-vision CCD camera 102
1 and the recording devices 115 connected to the distributor 111,
It comprises a monitor 114, a stereoscopic viewer 113, and the like.

The above-mentioned stereo microscope 101 is detachably fixed to the tip of the free arm 100a of the first stand 100 via a mount mounted on the back surface. Therefore, the stereoscopic microscope 101 is provided with the first stand 1
The free arm 100a can move freely and can face any direction within the radius that the free arm 100a can reach. However, here, for convenience, the direction of the subject with respect to the stereo microscope 101 is defined as “down”, and the opposite direction is “up”.
Shall be defined as

The optical configuration of the stereo microscope 101 will be described in detail later.
The object to be observed is a CCD 11 in the high-vision CCD camera 102 by a pair of left and right zoom optical systems and a relay optical system that converge light transmitted through different portions in a large-diameter close-up optical system having a single optical axis.
6 is formed.

With such a pair of photographing optical systems, CC
Left and right imaging regions on the imaging surface of D116 (two regions divided in the direction of the base line length on the imaging surface)
Is equivalent to a stereo image in which images respectively taken from two locations separated by a predetermined base line length are arranged on the left and right. The output signal of the CCD 116 is generated as a Hi-Vision signal by the image processor 117, and is output from the Hi-Vision CCD camera 102 to the distributor 111.
Output to. Note that the stereoscopic microscope 101 has a built-in illumination optical system 300 (see FIG. 3) for illuminating the observation object. The illumination optical system 300
, Illumination light is introduced from the light source device 106 via the light guide fiber bundle 105.

The HDTV signal output from the HDTV CCD camera 102 is distributed by a distributor 111 to a stereoscopic viewer 113 for the operator D, a monitor 114 for other surgical staff or an advisor at a remote location,
Then, they are supplied to the recording device 115, respectively.

The stereoscopic viewer 113 includes the second stand 1
Twelve free arms 112a are attached by hanging from the tips. Therefore, it is possible to arrange the stereoscopic viewer 113 according to a posture in which the main operator D can easily perform the treatment. As shown in FIG. 2, the stereoscopic viewer 113 includes a high-definition LCD panel 120.
Is built in as a monitor. This LCD panel 1
When an image based on a high-definition signal from the distributor is displayed on the area 20, the CCD 1 is located in the left area 120b.
The video captured in the left capturing area in 16 is displayed, and the video captured in the right capturing area in the CCD 116 is displayed in the right area 120a. Therefore, through a pair of left and right loupes provided for each of the left and right regions 120a and 120b, the main operator D can display the left and right images displayed in the left and right regions 120a and 120b with both eyes. , It is possible to stereoscopically view an enlarged image of the observation target.

(Configuration of Stereo Microscope) Next, a specific configuration of the above-described stereo microscope 101 (including the high-vision CCD camera 102) will be described in detail.

<Optical Configuration> FIG. 3 is a perspective view showing the optical system of the stereo microscope 101.

As shown in FIG. 3, the optical system in the stereo microscope 101 is a photographing optical system 2 for electronically photographing an image of a subject.
The illumination optical system 300 illuminates a subject with illumination light guided from the light source device 106 by the light guide fiber bundle 105.

As described above, the photographing optical system 200 has a single close-up optical system 210 shared by the left and right and a pair of left and right objective optical systems composed of a pair of left and right zoom optical systems 220 and 230, as described above. And a pair of left and right relay optical systems 240 and 25 for relaying a primary image of the subject formed by the objective optical system and forming a secondary image of the subject.
0, and a converging prism 260 as an inter-optical axis distance reducing element for bringing the subject light from these relay optical systems 240 and 250 closer to each other.

Field stops 270 and 271 are arranged at positions where the primary optical images are formed by the zoom optical systems 220 and 230, respectively.
Inside, a pentaprism 272 that deflects the optical path at right angles,
273 are respectively arranged.

With such a configuration, the CCD camera 10
The left and right subject images having a predetermined parallax can be formed in two adjacent regions on the CCD 116 arranged in the second CCD 2. In the description of the optical system, “left and right” is C
When projected onto the CD 116, the direction coincides with the longitudinal direction of the imaging surface, and “up / down” refers to the direction orthogonal to the left / right direction on the CCD 116. Hereinafter, the configuration of each optical system will be described in order.

The close-up optical system 210 is constructed by arranging a negative first lens 211 and a positive second lens 212 in order from the object side. Second lens 21
Reference numeral 2 is movable in the optical axis direction, and can adjust the movement to focus on objects at different distances. That is, since the close-up optical system 210 adjusts the second lens 212 so that the main subject (observation target) is located at the object side focal position, the divergent light from the main subject (observation target) is substantially reduced. It has a collimating function for converting into parallel light.

The first and second lenses 211 and 212 constituting the close-up optical system 210 extend along a plane passing through a position parallel to the optical axis and slightly deviated from the optical axis, and are positioned at a higher position than the plane. The outer edge is cut off. Therefore, when viewed from the direction of the optical axis, each of the planar shapes has a D-cut shape, so that there is a space beside the cutout surface. In this space, the illumination optical system 300 is arranged with its optical axis Ax4 parallel to the optical axis Ax1 of the close-up optical system 210.

The pair of zoom optical systems 220 and 230 function as image forming optical systems for forming subject light from the close-up optical system 210 at infinity at the positions of the field stops 270 and 271 respectively.

One zoom optical system 220 has first to fourth lens groups 221, 222, 222 having positive, negative, negative, and positive powers, respectively, from the close-up optical system 210 side.
223, 224, and the first and fourth lens groups 2
21 and 224 are fixed, and the second and third lens groups 222 and 2 are fixed.
23 is moved in the optical axis direction to perform zooming. mainly,
The magnification is changed by moving the second lens group 222 that is a variable power lens, and the focal position is kept constant by moving the third lens group 223 that is a compensator lens.

The other zoom optical system 230 has the same configuration as the above-described zoom optical system 220, and includes first to fourth lens groups 231, 232, 233, and 234. These zoom optical systems 220 and 230 are linked by a zoom lens barrel 2 described later, and can simultaneously change the photographing magnification of the left and right images.

The optical axes Ax2 of the zoom optical systems 220 and 230
Ax3 is arranged to be offset parallel to the optical axis Ax1 of the close-up optical system 210. However, the optical axes Ax2 and Ax3 of the zoom optical systems 220 and 230 are equidistant from each other with respect to the optical axis Ax1 of the close-up optical system 210 and at positions where the distances from the notch plane are equal to each other.
Offset. When viewed from the optical axis Ax1 direction of the close-up optical system 210, the optical axis Ax1 of the close-up optical system 210 and the optical axes Ax2 and Ax3 of both zoom optical systems 220 and 230 form an obtuse angle of the position of the optical axis Ax1. They are arranged to form an isosceles triangle with vertices.

The diameter of the close-up optical system 210 is set to be larger than the diameter of a circle containing the maximum effective diameter of the zoom optical systems 220 and 230 and the maximum effective diameter of the illumination optical system 300. Therefore, both zoom optical systems 220 and 23
The 0 optical axes are deflected by the close-up optical system 210 and cross each other at the object-side focal position of the close-up optical system 210. As a result, both zoom optical systems 2
At the image-side focal positions 20 and 230, images equivalent to those obtained by imaging the same object from two positions separated by a predetermined base line length are respectively formed.

The field stops 270 and 271 are arranged at positions that are planned as the image forming positions of the primary images by the zoom optical systems 220 and 230 created as designed. The field stop 270, 271 has a circular outer shape and a semicircular opening inside each of the left and right directions. Each field stop 27
0,271 indicates that the linear edge of this opening is the CCD 11
6 are arranged so as to correspond to the direction corresponding to the boundary line between the left and right images and transmit only the light flux inside the same.

The relay optical systems 240 and 250 have the function of re-forming the primary image formed by the zoom optical systems 220 and 230 as described above, and each is constituted by three positive lens groups.

One relay optical system 240 includes a first lens group 241 composed of a single positive meniscus lens,
The second lens group 242 is composed of negative and positive lenses and has a positive power as a whole, and the third lens group 243 includes a single biconvex lens. The first lens group 241 and the second lens group 242 have the object-side focal point as a whole fixed at the image forming plane of the primary image by the zoom optical system 220 (the same plane as the field stop 271). The third lens group 243 causes the parallel light emitted from the second lens group 242 to converge on the imaging surface of the CCD 116. A pentaprism 272 for deflecting the optical path at right angles is disposed between the first lens group 241 and the second lens group 242, and a light amount adjustment is provided between the second lens group 242 and the third lens group 243. Aperture 244 for
Is provided.

The other relay optical system 250 has the same configuration as the above-mentioned relay optical system 240, and includes first, second, and third lens groups 251, 252, and 253. A pentaprism 273 is disposed between the second lens group 252 and the lens group 252, and a brightness stop 254 is provided between the second lens group 252 and the third lens group 253.

The divergent light that has passed through the field stops 270 and 271 is again converted into substantially parallel light by the first lens groups 241 and 251 and the second lens groups 242 and 252 of the relay optical system. After passing through, the light is converged again by the third lens groups 243 and 253 to form a secondary image.

A convergence shifting prism 260 disposed between the relay optical systems 240 and 250 and the CCD camera 102
Has a function of narrowing the left and right intervals of subject light from the respective relay optical systems 240 and 250. In order to obtain a stereoscopic effect by stereoscopic vision, left and right zoom optical systems 220 and 23 are used.
0, a predetermined base line length is required between the relay optical systems 240 and 250. On the other hand, in order to form a secondary image in an adjacent area on the CCD 116, the distance between the optical axes needs to be smaller than the base length. Therefore, the congestion approaching prism 260
By shifting the optical axis of the relay optical system inward, the same CCD can be maintained while maintaining a predetermined base line length.
It is possible to form an image on the image 116.

The convergence shifting prism 260 is formed by joining pentagonal prism symmetrical optical axis shift prisms 261 and 262 (with a predetermined gap).
Each of the optical axis shift prisms 261 and 262 has an incident end face and an exit end face that are parallel to each other, and has first and second reflective surfaces that are parallel to each other inside and outside. When viewed in a plane perpendicular to the entrance and exit end faces and the reflection surface, these optical axis shift prisms 261 and 262 form one of the acute apex angles of the parallelogram as a line perpendicular to the exit end face. It is a pentagonal shape formed by cutting out the surface, and the surface formed by cutting out is a joining surface.

The subject light from the relay optical systems 240 and 250 enters from the entrance end faces of the optical axis shift prisms 261 and 262, is reflected by the outer reflecting surface, is directed inward in the left-right direction, and is directed to the inner reflecting surface. Is reflected again in the same optical axis direction as at the time of incidence, exits from the exit end face, and is
Incident on. As a result, the left and right object lights are narrowed only in the left and right intervals without changing their traveling directions, and the same CCD 1
16 to form a secondary image.

The illumination optical system 300 has a function of irradiating the object with illumination light.
5 includes an illumination lens 310 for adjusting the degree of divergence of the divergent light emitted from the lens 5 and a wedge prism 320 for matching the illumination range and the photographing range. Lighting lens 3
The optical axis Ax4 of 10 is the optical axis of the close-up optical system 210.
Since it is parallel to Ax1 and decentered by a predetermined amount, the center of the illumination range and the center of the photographing range do not match, and the amount of illumination light is wasted. By providing the wedge prism 310, the above mismatch can be eliminated, and the amount of illumination light can be used effectively.

<Optical System Holding Mechanism> Next, a pair of left and right zoom optical systems 220 and 23 of the above-described photographing optical system 200 are described.
The mechanical configuration of a mechanism that holds the “0” in the housing 1 of the stereoscopic microscope 101 will be described. FIG. 4 shows each of the zoom optical systems 220 and 2.
FIG. 3 is a schematic longitudinal sectional view (part) of the stereoscopic microscope 101 along a plane including both the 30 optical axes Ax2 and Ax3. FIG.
Is a cross section taken along line VV in FIG.
6 is a schematic longitudinal sectional view taken along line VI-VI in FIG. 5, and FIGS. 7 and 8 are zoom optical systems 220. And FIG. 230 are partial front views of the stereoscopic microscope 101 in the vicinity of the second and third lenses 222, 223, 232, and 233.

As shown in these figures, both zoom optical systems 220 and 230 are held by a common zoom lens barrel 2. The zoom lens barrel 2 includes a cylindrical fixed ring 3 fixed inside the housing 1, a cam ring 4 fitted in the fixed ring 3 so as to be rotatable only, and a straight line in the cam ring 4. The two lens frames (the second lens frame 5 and the third lens frame 6) which are inserted only as possible constitute a main configuration.

The fixed ring 3 has a substantially cylindrical shape with a bottom, and a circular through hole 3 having a center at a position where the optical axes Ax2 and Ax3 of the zoom optical systems 220 and 230 pass through the bottom 3a.
b, 3c are formed. Also, D in each of the lenses 211 and 212 constituting the close-up optical system 210
An illumination hole 3d substantially overlapping the cut portion (substantially half-moon-shaped portion) is formed. And both through holes 3b, 3c
First lens frames 7, 7 each having a cylindrical shape having substantially the same inner diameter as these and holding the first lens groups 221 and 231 are fixed to the lower edge thereof.

Further, three locations at equal angular intervals in the circumferential direction of the fixed ring 3 (a plane orthogonal to a plane including both optical axes Ax2 and Ax3, and a plane including the central axis of the fixed ring 3 are connected to the illumination hole 3d). Are located at a position where the fixed ring 3 intersects with the distant side and two positions which are displaced by 120 degrees in the circumferential direction from the distant side).
A straight through groove (straight-moving groove) 3e is formed in parallel with the central axis.

The upper side of the stationary ring 3 (relay optical system side)
A disk-shaped lid 8 is fitted into the open end of the disk. Each of the through holes 3 b and 3 c of the fixed ring 3 and the illumination
Corresponding to d, there are formed through holes 8b and 8c centered on the passing positions of both optical axes Ax2 and Ax3 and an illumination hole 8d having the same shape and position as the illumination hole 3d. The fourth lens frames 9, 9 holding the fourth lens groups 224, 234 of the zoom optical systems 220, 230 therein are fixed to the through holes 8b, 8c in a penetrating state.

The cam ring 4 is formed to be shorter by a small clearance in the axial direction than the distance from the bottom 3a of the fixed ring 3 to the lid 8. This cam ring 4 has 120
A pair of cam grooves for driving the two lens frames 5 and 6 (the first cam groove 4a for driving the second lens frame 5 and the third lens frame 6 are driven at equal angular intervals every step) A second cam groove 4b) is formed. The positions of the respective ends of the two cam grooves 4a and 4b coincide with each other in the circumferential direction. The area occupied by the cam grooves 4a and 4b in the axial direction coincides with the area occupied by the rectilinear groove 3e in the axial direction.

Each of the lens frames 5 and 6 has a flat bottomed cylindrical shape having an outer diameter substantially equal to the inner diameter of the cam ring 4. The second lens frame 5 is fitted into the cam ring 4 with its open end facing upward (toward the relay optical system), and the third lens frame 6 has its open end facing downward (closed). (To the up optical system side). On the outer peripheral surface of the second lens frame 5, each of the rectilinear grooves 3 e and each of the first cam grooves 4
Three cam followers 10 penetrating the three intersections with a are planted. Each cam follower 10 includes a cam pin fixed to the lens frame 5 and a cylindrical collar that rotates around the cam pin. Similarly, on the outer peripheral surface of the third lens frame 6, three cam followers penetrating through three intersections of each straight groove 3 e and each second cam groove 4 b in a state of being fitted into the cam ring 4. 11 are planted. Each cam follower 11 is a cam follower 10
It has the same configuration as. Therefore, these two lens frames 5, 6
Are restricted from rotating with respect to the fixed ring 3 and are positioned at an axial position corresponding to the rotational position of the cam ring 4.

The illumination holes 5d and 6d overlapping with the illumination hole 3d of the fixed ring 3 and the illumination hole 8d of the lid 8 are opened in the two lens frames 5 and 6, respectively, in such a state that the rotation is restricted. I have. The second lens frame 5 has both optical axes Ax2 and Ax3.
The lens-fixed cylindrical portions 5b and 5c having a cylindrical shape are integrally formed so as to protrude downward. At approximately the center of the interior of these two lens fixing cylinder portions 5b and 5c, respectively,
Second lens groups 222 and 232 are held. Also,
Also in the third lens frame 6, cylindrical lens fixing cylinders 6b and 6c are integrally formed coaxially with both optical axes Ax2 and Ax3 so as to protrude downward. These two lens fixing cylinders 6
b and 6c, the third lens group 223 and
233 are held. Note that the inner diameters of both lens fixing cylindrical portions 6b and 6c are such that the lower ends of the fourth lens frames 9 and 9 enter the inside thereof, and the third lens groups 223 and 233 are opposed to the fourth lens groups 224 and 234. The fourth lens frames 9 are formed to be larger than the outer diameter of the lower end of the fourth lens frames 9 so that they can approach each other.

As shown in FIGS. 4, 7 and 8, at the center of the third lens frame 6, a cylindrical spring end fixing cylinder 6e coaxial with the center axis protrudes upward. It is integrally formed in a state. Similarly, at the center of the bottom 3a of the fixed ring 3, a cylindrical spring end fixed cylindrical portion 3f coaxial with the center axis thereof is integrally formed so as to protrude downward.
Further, near the upper open end of the spring end fixed cylindrical portion 6e and near the lower open end of the spring end fixed cylindrical portion 3f, the rod-shaped members 3 for hooking the ends of the tension springs 18 are respectively provided.
g, 6f are formed so as to be orthogonal to the central axis.
At the center of the second lens frame 5, a through hole 5e for passing the tension spring 18 is formed, and at the center of the lid 8 of the fixed ring 3, a through hole 8e into which the spring end fixed cylindrical portion 6e enters. Are formed. Further, the tension spring 18 is used for the rod-shaped member 3 when the third lens frame 6 is closest to the bottom 3 a of the fixed ring 3.
It has a free length shorter than the length between g and 6f.

Therefore, these spring end fixed cylindrical portions 3f, 6e
And the tension spring 18 is inserted into the through hole 5e,
Both ends of the tension spring 18 are fixed to the respective spring end fixed cylindrical portions 3f, 6e.
In the state of being hooked on the rod-shaped members 3g and 6f, the third
The lens frame 6 is urged toward the bottom 3 a of the fixed ring 3.
The urging force applied to the third lens frame 6 is
Is transmitted to the cam ring 4 because the cam follower 11 presses the second cam groove 4b of the cam ring 4 downward. Therefore, the cam ring 4 to which the urging force applied to the third lens frame 6 is transmitted is always pressed against the bottom 3 a of the fixed ring 3.

At the lower end of the inner peripheral surface of the cam ring 4 described above, an annular gear 15 having teeth formed on the inner periphery is fitted and fixed. This annular gear 15 has a bottom 3 a of the fixed ring 3.
The pinion 17 attached to the drive shaft of the motor 16 fixed to the gear is engaged. Therefore, this motor 1
6 rotates the pinion 17 in an appropriate direction by an appropriate amount, so that the cam ring 4 rotates by an arbitrary angle in an arbitrary direction. As a result, the second lens groups 222 and 232 and the third lens groups 223 and 2 held by the respective lens frames 5 and 6
33 is moved to a position uniquely determined by the shapes of both cam grooves 4a and 4b, and the photographing magnification by the photographing optical system 200 changes. Then, even during this movement, since the urging force applied to the third lens frame 6 is applied to the cam ring 4, the cam ring 4 is pressed against the bottom 3 a of the fixed ring 3.

As described above, according to the zoom lens barrel 2 of the first embodiment, the urging force of the tension spring 18 transmitted through the third lens frame 6 causes the cam ring 4 to constantly fix the cam ring 4.
Therefore, even when the zoom lens barrel 2 is oriented in various directions, the cam ring 4 does not separate from the bottom 3 a of the fixed ring 3. Therefore, the cam ring 4 does not move in the optical axis direction within the range of the clearance with the fixed ring 3, and the focus position is not shifted. Further, even if a driving force in an arbitrary rotation direction is applied to the cam ring 4 by driving the motor 16, the cam ring 4 is always pressed against the bottom 3 a of the fixed ring 3,
Does not fall, thereby preventing the second and third lens groups 222, 232, 223 and 233 from being decentered with respect to the optical axes Ax2 and Ax3 of the respective objective optical systems.

As shown in the plan view of FIG. 5, three locations (e.g., clockwise displaced from the respective cam followers 10 when viewed from above) at equal angular intervals on the inner peripheral surface of the second lens frame 5. Positions) are each fixed with a hook 12 for hanging a spring. Similarly, spring-hook hooks are also provided at three locations on the inner peripheral surface of the third lens frame 6 at equal angular intervals (positions slightly counterclockwise from the cam followers 11 when viewed from above). 13 is fixed. Then, each hook 12 of the second lens frame 5 whose rotation is regulated by each of the cam followers 10 and 11.
And three hooks 13 of the third lens frame 6 corresponding to each of the three hooks so as to obliquely cross each rectilinear groove 3e from the lower left to the upper right when viewed from the outside of the fixed ring 3. The tension springs 14 are hung respectively (see the middle tension spring 14 and the straight groove 3e in FIGS. 7 and 8). 4 to 8 show the tension springs 14 existing on the near side of the cross section.
And hooks 12 and 13 are also shown in an overlapping manner. Due to the contraction force of each of the tension springs 14, each of the cam followers 10 of the second lens frame 5 causes the counterclockwise inner edge of the rectilinear groove 3e and the upper inner edge of the first cam groove 4a when viewed from above. And the cam followers 11 of the third lens frame 6 always contact the clockwise inner edge of the rectilinear groove 3e and the lower inner edge of the second cam groove 4b when viewed from above. Accordingly, the side edges of the cam grooves 4a, 4b and the rectilinear grooves 3e to which the cam followers 10, 11 abut are switched in accordance with the direction of rotation of the cam ring 3, and the rectilinear grooves 3e, the first and second cam grooves 4a. , 4b, the cam followers 10, 11 do not shift.

Incidentally, the stationary ring 3, the second lens frame 5, the third lens frame 6, and the illumination holes 3d, 5d, 6d, 8d of the lid 8 are provided.
Have the same shape, and do not shift in the circumferential direction regardless of the rotational position of the cam ring 4. The light guide fiber bundle 105 for introducing illumination light into the illumination optical system 300 is provided with these illumination holes 3d, 5d, 6d,
8d and fixed. Therefore, regardless of the existence of the light guide fiber bundle 105, both zoom optical systems 220 and 230 can be accommodated in the common zoom lens barrel 2.

[0062]

Second Embodiment A second embodiment of the present invention is different from the first embodiment in that the third lens frame 6 is urged toward the bottom 3a of the fixed ring 3 as in the first embodiment. All the configurations are the same except that the configuration is such that the configuration is such that the cover is biased toward the lid 8 of the fixed ring 3. Therefore, only the differences between the second embodiment and the first embodiment will be described below. 9 and 10 show the optical axes Ax2 and Ax of the zoom optical systems 220 and 230, respectively.
FIG. 3 is a schematic vertical cross-sectional view (part) of the stereoscopic microscope 101 along a plane including both of them.

As shown in these figures, the center of the lid 8 has a cylindrical spring-end fixed cylindrical portion 8 coaxial with its central axis.
f is integrally formed so as to protrude upward. Similarly, at the center of the second lens frame 5, a cylindrical spring end fixed cylindrical portion 5 f coaxial with the center axis thereof is integrally formed so as to protrude downward. In the vicinity of the lower open end of the spring-end fixed cylindrical portion 5f and the vicinity of the upper open end of the spring-end fixed cylindrical portion 8f, bar-shaped members 5g and 8g for hooking the ends of the tension springs 18 are provided, respectively. It is formed so as to be orthogonal to the central axis. In the center of the third lens frame 6, a through hole 6f for passing the tension spring 18 is formed, and in the center of the bottom 3a of the fixed ring 3, a through hole 3h into which the spring end fixed cylindrical portion 5f enters. Are formed. Also, the tension spring 18
Is a free length shorter than the length between the rod-shaped members 5g and 8g when the second lens frame 5 is closest to the lid 8 of the fixed ring 3.
Have.

Accordingly, these spring end fixed cylindrical portions 5f, 8f
And the tension spring 18 is inserted into the through hole 6f,
In a state where both ends of the tension spring 18 are hooked on the respective bar-shaped members 5g, 8g of the spring-end fixed cylindrical portions 5f, 8f, the second
The lens frame 5 is urged toward the lid 8 of the fixed ring 3. This urging force applied to the second lens frame 5 is also transmitted to the cam ring 4 because the cam follower 10 of the second lens frame 5 presses the first cam groove 4a of the cam ring 4 upward. Therefore, the second
The cam ring 4 to which the urging force applied to the lens frame 5 is transmitted is always pressed against the lid 8 of the fixed ring 3.

As described above, the biasing force of the tension spring 18 transmitted through the second lens frame 5 is also transmitted by the zoom lens barrel 2 'of the second embodiment, as in the first embodiment, as in the first embodiment. Always presses the cam ring 4 against the fixed ring 3,
Even when the zoom lens barrel 2 is oriented in various directions,
The cam ring 4 does not separate from the lid 8 of the fixed ring 3. Further, since the cam ring 4 is constantly pressed against the lid 8 of the fixed ring 3 as described above, even if a driving force in an arbitrary rotational direction is applied to the cam ring 4 by driving the motor 16, The center axis of the cam ring 4 does not fall.

[0066]

As described above, according to the binocular lens barrel of the present invention, the cylindrical fixed ring is used to move a part of the lens groups constituting the pair of right and left objective optical systems in synchronization with each other. Despite the configuration in which the lens frame is moved in the direction of the central axis by rotating the cylindrical cam ring with respect to, even when a large clearance is taken between the fixed ring and the cam ring, the lens frame is kept within the range. The movement of the cam ring in the optical axis direction is restricted, and the cam ring is prevented from falling in the optical axis direction. As a result, the enlarged image of the observation target can be stereoscopically viewed in a natural state without any discomfort.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a surgery support system incorporating a video stereo microscope according to a first embodiment of the present invention;

FIG. 2 is a plan view of an LCD panel built in a stereoscopic viewer constituting the surgery support system of FIG. 1;

FIG. 3 is a perspective view showing an optical system of a video stereo microscope.

FIG. 4 is a schematic longitudinal sectional view of a video stereo microscope along a base line length direction.

FIG. 5 is a schematic cross-sectional view taken along line VV in FIG.

6 is a schematic longitudinal sectional view taken along the line VI-VI in FIG.

FIG. 7 is a partial cross-sectional front view of a part of a zoom lens barrel constituting the video stereo microscope.

FIG. 8 is a partial cross-sectional front view of a part of a zoom lens barrel constituting the video stereo microscope.

FIG. 9 is a schematic longitudinal sectional view along a base line length direction of a zoom lens barrel constituting a video stereoscopic microscope according to a second embodiment of the present invention.

FIG. 10 is a schematic longitudinal sectional view of the zoom lens barrel along a base line length direction.

FIG. 11 is a longitudinal sectional view of a conventional zoom lens barrel taken along a base line length direction.

FIG. 12 is a longitudinal sectional view of a conventional zoom lens barrel taken along a direction perpendicular to a base line length direction.

FIG. 13 is a perspective view showing an assembled state of both lens frames and a tension spring constituting a conventional zoom lens barrel.

[Explanation of symbols]

 Reference Signs List 1 housing 2 zoom lens barrel 3 fixed ring 4 cam ring 4a first cam groove 4b second cam groove 5 second lens frame 6 third lens frame 10 cam follower 11 cam follower 12 hook 13 hook 14 extension spring 18 extension spring 18 extension spring 220 zoom optical System 222 Second lens group 223 Third lens group 230 Zoom optical system 232 Second lens group 233 Third lens group

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/10 G02B 21/22 21/22 7/04 D

Claims (4)

[Claims] 1. A binocular lens barrel for holding a moving lens group in a pair of objective optical systems for forming images of the same object from positions separated by a predetermined base line length, respectively. A fixed ring formed of a cylindrical member having a central axis parallel to the optical axis of the optical system, a straight groove formed parallel to the central axis, and a cylindrical member having a central axis parallel to the optical axis; A cam ring, which is rotatably fitted only to the fixed ring and has a cam groove having a portion inclined with respect to the center axis thereof, and the optical axis inside the fixed ring and the cam ring. A lens frame that is held movably only in a parallel direction and that holds the moving lens groups in the two objective optical systems together; and a lens frame that is attached to the lens frame and that has the rectilinear groove and the cam groove. Camfo penetrating the intersection A binocular lens barrel comprising: a lower member; and a biasing member that biases the lens frame toward an end of the fixed ring. 2. Each of the objective optical systems includes two moving lens groups, and the cam groove, the lens frame, and the cam follower are provided corresponding to the moving lens groups, respectively. 2. The binocular lens barrel according to claim 1, further comprising a second urging member that relatively urges the two lens frames in a direction oblique to the optical axis. 3. 3. The apparatus according to claim 2, wherein a plurality of said rectilinear grooves, said cam grooves, said cam followers and said second biasing member are provided at equal angular intervals around the central axis of said fixed ring and said cam ring. The binocular lens barrel according to claim 2. 4. The binocular lens barrel according to claim 1, wherein said urging member is a tension spring.