JPH08327870A - Eccentricity adjusting method for lens barrel and lens system - Google Patents

Abstract

PURPOSE: To provide an eccentricity adjustment method for lens barrel and lens system by which the eccentricity adjustment for a 1st lens group and a 2nd lens group is accurately secured and the 1st and the 2nd lens groups are surely fixed. CONSTITUTION: The lens barrel is provided with the 1st lens group L2, the 2nd lens group L3, a holding member 50 holding the lens group L2, a holding member 11 holding the lens group L3, projecting parts 50c at plural spots on the outer circumference of one holding member, projecting parts 11e, corresponding to the projecting parts at plural spots on the outer circumference of the one holding member, on the inner circumference of another holding member, and a clearance (c) through which the eccentricity adjustment for either holding member is performed when the other holding member is rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel capable of adjusting decentering of a first lens group and a second lens group, and a method of adjusting decentering of a lens system.

[0002]

2. Description of the Related Art Conventionally, as a method for adjusting the eccentricity of a lens,
As described in Japanese Utility Model Laid-Open No. 5-36410, appropriate play is provided on the lens outer diameter and the inner peripheral surface of the lens holding member, and the outer diameter of the lens is adjusted from the outer peripheral direction of the holding member by a plurality of adjusting screws. There is a mechanism for adjusting the eccentricity of a plurality of lenses by bringing them into contact with each other. In addition, JP-A-6-265766
As described in Japanese Patent Laid-Open Publication No. 2003-242242, parallel light passing through the first and second lens systems is used to obtain an alignment correction amount by performing image processing on the imaging performance, and one of the lens systems is directly connected. There is a method of adjusting the amount of correction with an adjusting jig and then adhering.

[0003]

However, in the above-mentioned prior art, in the adjusting screw method described in Japanese Utility Model Laid-Open No. 5-36410, since the lens is directly pushed, the surface opposite to the body-bearing surface of the lens is adjusted. Not only does it cause a tare on the lens, but during the lens adjustment, the press ring is loosened and then tightened again after adjustment, so there is a high possibility that the lens will move when the press ring is tightened. .

Further, as described in Japanese Patent Application Laid-Open No. 6-265766, the alignment performance is corrected by image-processing the image-forming performance by utilizing the parallel light transmitted through the first and second lens systems. The method of determining the amount, adjusting one lens system directly by the adjustment amount by the adjustment amount, and adhering it is possible only when the lens to be adjusted can be moved directly by the adjustment jig. Adjustment is difficult when the system is composed of a plurality of lenses.

Further, in all of the conventional techniques, it is premised that the eccentricity is adjusted for all the produced lens systems. Therefore, there is a problem that it takes time and effort for adjustment.

By the way, depending on the lens, it is often the case that the lens performance can be ensured by the component precision without necessarily performing the eccentricity adjustment. Even if it is difficult to secure a 100% good product due to variations in component tolerances, it may be sufficient to secure a good product by adjusting the eccentricity only for defective products. However, in the conventional technology, such an idea has not been considered at all.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is the first
An object of the present invention is to provide a structure of a lens barrel capable of accurately adjusting the eccentricity of the lens group and the second lens group.

Another object of the present invention is to provide an eccentricity adjustment of a lens system which can accurately perform the eccentricity adjustment of the first lens group and the second lens group.

[0009]

To achieve the above object, according to one aspect of the present invention, in a lens barrel having a first lens group and a second lens group, a first lens group is provided. And a second holding member for holding the second lens group. The first holding member and the second holding member are fitted to each other so that one of them is coaxially fitted to the other. The fitting portion has an inward projecting portion that projects inward on the inner circumference of the outer fitting member and an outward projecting portion that projects outward on the outer circumference of the inner fitting member. , And each of the inner fitting member and the outer fitting member has no radial play when the tip of the inward projection and the tip of the outward projection are in contact with each other, and there is no inward projection. Has a structure with radial play when it is not in a position where the tip of the part and the tip of the outwardly projecting part abut. The lens barrel is provided, characterized and.

Here, a plurality of inward projections and outward projections can be provided at corresponding angular positions.

Further, the first holding member and the second holding member are
It can be fixed with an adhesive while one is coaxially fitted to the other.

Further, the first holding member and the second holding member respectively have contact surfaces that contact each other in the optical axis direction,
In addition, a recess may be provided on one of the contact surfaces, and the recess may be filled with an adhesive for bonding the first holding member and the second holding member. In this case, two types of recesses are provided, a first recess and a second recess.

One of the first holding member and the second holding member has a flange, and the other of them has a cylindrical opening end that abuts the flange, and the end face of the opening end and the flange. The first surface and the second surface may be provided so as to form contact surfaces. In this case, a first recess is provided on the end face of the opening end, the flange has a through hole at a position facing the first recess when abutting, and the outer periphery of the end face of the opening end is provided. The second recess may be provided on the side.

The first concave portion is filled with, for example, a short-time curing type first adhesive, and the second concave portion is filled with, for example, a non-short-time curing type second adhesive. can do.

According to another aspect of the present invention, a first holding member for holding the first lens group and a second holding member for holding the second lens group are provided, and the first holding member is provided. The second holding member has a fitting portion for fitting one side coaxially with the other, and the fitting portion is an inward projecting portion that projects inwardly on the inner circumference of the outer fitting member. Has an outwardly projecting portion projecting outwardly on the outer periphery of the inner fitting member,
In addition, the inner fitting member and the outer fitting member have no radial play when the tip of the inward protruding portion and the tip of the outward protruding portion are in contact with each other, and there is no play in the radial direction. A method for adjusting the eccentricity of a lens system having a structure having radial play when the tip of the inward protruding portion is not in contact with the tip of the inward protruding portion. Whether the optical axes of the first lens group and the second lens group are decentered with the first holding member and the second holding member fitted so that they are in contact with each other at the tip end If there is no eccentricity, the first holding member and the second holding member are fixed with an adhesive in this state, and if there is eccentricity,
Of the first holding member and the second holding member, one lens group is fixed, and the holding member of the other lens group is displaced in a direction orthogonal to the optical axis of the fixed lens group to fix the lens. There is provided an eccentricity adjusting method for a lens system, which is characterized in that the optical axes of the lens group and the other lens group are aligned with each other, and in this state, the first holding member and the second holding member are fixed with an adhesive.

[0016]

The first holding member and the second holding member are fitted so that their fitting portions are coaxial with each other. At this time, the first holding member and the second holding member are fitted so that the tip of the inward protruding portion and the tip of the outward protruding portion are in contact with each other in the fitting portion. In this state, the tip of the inward protruding portion and the tip of the outward protruding portion are in contact with each other, so that the first holding member and the second holding member are fixedly fitted to each other.

In this state, the presence or absence of decentering of the optical axes of the first lens group and the second lens group is detected. The method of detecting the presence or absence of eccentricity is, for example, a method used in the embodiments described later.
Here, when there is no eccentricity, the first holding member and the second holding member are fixed with an adhesive in this state.

On the other hand, when there is eccentricity, when there is eccentricity, one of the first holding member and the second holding member is rotated so as to rotate the tip of the inward projection and the tip of the outward projection. Do not touch and. Thereby, a play (clearance) is formed between the inner peripheral side and the outer peripheral side of the fitting portion. Therefore,
Of the first holding member and the second holding member, one of the lens groups is fixed, and the holding member of the other lens group is displaced in a direction orthogonal to the optical axis of the fixed lens group to fix the lens. The optical axes of the lens group and the other lens group are matched. Then, in this state, the first holding member and the second holding member are fixed with an adhesive.

As described above, the fitting protrusions corresponding to the positions provided on the respective holding members are set to be in a default state, and in a state where the fitting protrusions are fitted, specific surfaces of the lens groups are accurately arranged. If there is no problem, the mutual holding members can be fixed with an adhesive without adjusting the eccentricity. Therefore, unnecessary adjustment can be omitted, and eccentric adjustment, which is time-consuming, can be reduced as a whole. On the other hand, if the eccentricity accuracy is not reached, rotate one of the holding members by a predetermined amount,
By shifting the positions of the protrusions, mutual holding members can be adjusted.

The eccentricity adjustment is performed by fixing one lens group of the first holding member and the second holding member and fixing the holding member of the other lens group in a direction orthogonal to the optical axis of the fixed lens group. It is performed by displacing the fixed lens group and the optical axis of the other lens group to coincide with each other. Specifically, since the adjustment is performed by using the lens surface having the center of the radius of curvature in the same direction in each lens system, highly accurate adjustment is possible. Further, since either the holding member that holds the first lens group or the holding member that holds the second lens group is moved during the eccentricity adjustment, deterioration of the lens system does not occur. Only the eccentricity can be adjusted directly.

The first holding member and the second holding member are fixed with an adhesive. Therefore, each of the first holding member and the second holding member has an abutting surface that abuts each other in the optical axis direction, and one of the abutting surfaces is provided with a recess. The recess is filled with an adhesive for bonding the first holding member and the second holding member. For example, two types of recesses are provided, one of which is filled with a short-time curable adhesive, and the other of which is filled with a non-short-curable adhesive. Specifically, after adjusting the optical axes to coincide with each other, in this state, the first holding member and the second holding member are temporarily fixed with an adhesive of a short-time curing type, and further, a short-time curing type. The first holding member and the second holding member are fixed to each other with an adhesive which is not.

By thus fixing the first holding member and the second holding member with the adhesive, there is an advantage that the relative positional relationship between these members does not change after the adjustment. In particular, by using a short-time curable adhesive,
Since the first holding member and the second holding member can be fixed in a short time, the optical axis adjusted state can be held accurately. Also, by using an adhesive that is not curable for a short time, it can be firmly fixed. In this case, since the first holding member and the second holding member are fixed by the short-time curable adhesive, the first holding member and the second holding member due to the deformation caused by the curing process of the non-short-time curable adhesive. The occurrence of a change in the positional relationship with the holding member is suppressed.

[0023]

Embodiments of the present invention will be described below. Before describing the embodiments, an outline of the structure of the lens barrel will be first described, and then a holding structure for the lens groups L2 and L3 will be described, and then the lens barrel and the overall structure and operation will be described.

FIG. 2 is a sectional view of the lens barrel of the embodiment of the present invention. As shown in FIG. 2, the lens barrel of the present invention includes a male fixed mount 1 for mounting on a female mount of a camera body (not shown), a fixed portion 2 integrated with the fixed mount 1, and an optical axis. The zoom ring 3 for zooming by rotating the zoom ring 3 in the direction, the adjusting member 4 fixed to the zoom ring 3 so as to rotate integrally with the zoom ring 3 after assembly and adjustment, and the movement of the lens units L1, L2, L3 are controlled. And a male helicoid member 6 for zooming and moving the lens unit L1 in association with the cam ring 5.
A holding frame 7 for the lens unit L1, a drive ring 8 that rotates around the optical axis by a drive gear (not shown), and the fixed portion 2.
Straight advance interlocking key 10 that is positioned and fixed with screws 12
And a holding member 50 for holding the lens group L2 and a holding member 11 for holding the lens group L3.

Next, the holding structure of the lens groups L2 and L3 will be described with reference to FIG. FIG. 1 is a sectional view showing a holding structure for the lens groups L2 and L3.

As shown in FIG. 1, the structure for holding the lens group L2 and the lens group L3 includes a first holding member 50 for holding the lens group L2, and a second holding member 11 for holding the lens group L3. Equipped with. The lens group L2 includes the lens G.
4 and G5. The lens group L3 is composed of lenses G6 and G7. The lens unit L2 and the lens unit L3 are configured such that at least one lens surface (G5R1 surface and G6R2 surface) having the center of curvature radius in the same direction exists in each lens group. These surfaces are used in the optical axis adjustment described later.

The second holding member 11 includes lenses G6 and G6.
7, a lens holding part 111 for holding 7, a connecting part 113 having a larger diameter than that for connecting to the first holding member 50, and a flange part for integrally connecting the lens holding part 111 and the connecting part 113. And 112. The lens G6 is directly attached to the lens holding portion 111, and the lens G6
7 is held via the fixing member 21. Fixing member 21
Is formed in a tubular shape and holds the lens 7 at one end thereof. Further, the fixing member 21 has a screw thread cut on the outer circumference and is screwed with a screw cut on the inner circumference of the lens holding portion 111.

The connecting portion 113 engages with the cam ring 5 and is held by the cam ring 5 on the outer circumference thereof. Also,
At the end of the connecting portion 113, the opening end surface 1 that functions as an abutting surface that abuts the first holding member 50 in the optical axis direction.
Have 1f. The opening end surface 11f is provided with two types of recesses. That is, the concave groove 11d is provided as the first concave portion. The groove 11d has, for example, a depth of about 0.03 to 0.05 mm, a length of about 4 mm, and a width of about 2 mm. In this embodiment, the concave groove 11d is
As shown in FIG. 4 (B), the opening end face 11f is provided at three positions at 120 ° intervals. Further, as the second concave portion, a cutout portion 11c that is deeper in the axial direction and longer in the circumferential direction than the concave groove 11d is provided.
The notch 11c has, for example, a depth of about 1 mm, a length of about 20 mm, and a width of about 1.5 mm. In this embodiment, the cutout portions 11c are provided at two positions on the opening end surface 11f. Of course, the shape, structure, size, and arrangement of the recessed groove 11d and the cutout portion 11c are merely examples. The reason why the notch 11c is not a groove but has a wall surface on the outer peripheral surface, that is, a stepped shape, is to allow the adhesive to be injected from the outer peripheral side. Therefore, other structures can be used as long as the adhesive can be injected.

The first holding member 50 includes lenses G4 and G4.
5, a lens holding unit 501 holding the lens 5, and a lens holding unit 50.
1. The lens holding part 501 which is provided integrally with
And a flange portion 503 that is integrally provided on the tip end side of the tubular body 502.

The flange portion 503 is a portion for fixing to the connecting portion 113 of the holding member 11 with an adhesive. The back surface 50f of the flange portion 503 has an opening end surface 11f.
And function as contact surfaces that contact each other in the optical axis direction. Further, the flange portion 503 is provided with a through hole 50a. The through hole 50a is provided corresponding to the position of the recessed groove 11d, as shown in FIGS. 1, 4A and 4B.

The connecting portion 113 and the tubular body 502 constitute a fitting portion for fitting one of the first holding member and the second holding member coaxially with the other. That is, the connecting portion 113 serves as an outer fitting member, and the tubular body 502 serves as an inner fitting member, and the both constitute a fitting portion. As shown in FIGS. 4 (B), 8 and 9, the inner periphery of the outer fitting member (113) has an inward protruding portion 11 protruding inward.
e is provided. Also, the inner fitting member (502)
As shown in FIG. 4C, FIG. 7, FIG. 8 and FIG. 9, an outer protruding portion 50c that protrudes outward is provided on the outer periphery of the. A plurality of inward protrusions 11e and outward protrusions 50c are provided at corresponding angular positions. In this embodiment, three pieces are provided at intervals of 120 degrees. of course,
It is not limited to this.

Further, the connecting portion 113 and the cylindrical body 502 are
When the tips of the inward protrusion 11e and the outward protrusion 50c are in contact with each other (default state), there is no play in the radial direction, and the tip of the inward protrusion 11e and the tip of the outward protrusion 50c are Has a structure having a radial play when it is not in the contact position. That is, the tubular body 5
Regarding the outer diameter of 02 and the inner diameter of the connecting portion 113, the outer diameter of the former is smaller than the inner diameter of the latter by 2c, excluding the protruding height of the protruding portion. That is, there is a gap c between the outer circumference of the tubular body 502 and the inner circumference of the connecting portion 113. Therefore, if the protrusion heights of the inward protruding portion 11e and the outward protruding portion 50c are set to be equal to each other, they are 1/2 of c respectively.
Becomes That is, in the range of play (clearance) c,
Eccentricity adjustment is possible. In the present embodiment, this c is, for example, about 0.1 mm.

Specifically, in the state shown in FIG. 8, since the tip of the inward protrusion 11e and the tip of the outward protrusion 50c are in contact with each other, the connecting portion 113 and the tubular body 502 are It is in a fixed state. On the other hand, in the state shown in FIG. 9, since the tip of the inward protruding portion 11e and the tip of the outward protruding portion 50c are not in contact with each other, the connecting portion 113 and the tubular body 502 are not present.
And are displaceable within a range of play (clearance) c. Therefore, with the state of FIG. 8 as the default, the presence or absence of eccentricity is checked first in this default state. If the eccentricity is within the allowable range, the holding members 50 and 11 are fixed without adjusting the eccentricity. On the other hand, if the eccentricity exceeds the permissible range, as shown in FIGS. 7 and 9, the holding member 50 is rotated counterclockwise to release the contact between the protrusions 11e and 50c, and the eccentricity is increased. The core can be adjusted. Then, after adjusting the eccentricity as described later, the holding members 50 and 11 are fixed.

Next, the fixing of the holding members 50 and 11 will be described. Fixing is performed using two kinds of adhesives.
That is, a short-time curable adhesive called instant adhesive,
For example, an ethyl cyanoacrylate-based adhesive and an adhesive that is not a short-time curing type, for example, an epoxy-based secondary adhesive are used. The short-time curing type adhesive 101 is dripped into the groove 11d through the through hole 50a. The epoxy-based secondary adhesive 10 is provided in the cutout portion 11c.
0 is filled. As a result, temporary fixing after eccentricity adjustment is reliably performed with the short-time curing type adhesive 101. Further, when the secondary adhesive is hardened, the first holding member 50 and the second holding member 11 are prevented from moving with the hardening of the secondary adhesive 100. Then, the epoxy-based secondary adhesive 10
At 0, the strength after the lens is assembled can be maintained.

Next, a method of adjusting the eccentricity of the lens system will be described. The decentering adjustment between the lens systems of the present invention is an application of the reflection decentering measuring method. FIG. 3 is an explanatory diagram of the principle of eccentricity adjustment of the lens system.

In each lens group, there are G5R1 surfaces and G6R2 surfaces having lens surfaces having centers of curvature in the same direction. Mutual eccentricity accuracy is required for these two surfaces, and the mutual eccentricity accuracy is 0.
It is necessary to keep the accuracy within 01 mm. The reflection eccentricity measuring method projects an index by a collimator lens on the center of the radius of curvature of the surface to be measured (G5R1 surface, G6R2 surface),
This is a method of checking the shift position of the reflected image. Lens group L
2 G5R1 surface reflection image (P1) and lens group L3 G
The reflection image (P2) of the 6R2 surface is simultaneously monitored. P2
It is determined that the core has come out by matching P1 with reference to. In the eccentricity adjustment of the lens of the present invention, two light sources (not shown) are used to create the reflection images of the two surfaces to be observed and form the images on the same surface.

Such eccentricity adjustment is specifically shown in FIG.
And the eccentricity adjusting device shown in FIG.

FIG. 5 is a schematic view of an example of a lens eccentricity adjusting device. The apparatus shown in FIG. 5 has an XY stage 610.
And a fine movement unit 630 installed thereon. First
The holding member 50 of the second lens unit L2 is installed in the lens chamber 631 of the XY stage 610, and the holding member 50 of the first lens unit L2 is directly pushed and pulled to perform shift adjustment. In the present embodiment, the fine movement part 630 has a structure that presses the second lens group holding member 50 from four directions. That is, the micrometer heads 632 and 633 are respectively provided in the two axial directions.
Equipped with respective micrometer heads 632, 63
On the opposite side of 3, the biasing mechanism 635, 63 with a built-in spring
6 are arranged respectively. Energizing mechanism 635,636
Thus, the holding member 50 of the first lens unit L2 is pressed against the micrometer heads 632 and 633 side. Therefore, the micrometers 632 and 633 are adjusted so that the deviation of the image formation point detected by the above-described method is eliminated.
By adjusting each, the eccentricity of the optical axis position of the first lens unit L2 is suppressed within the allowable range. The micrometer heads 632 and 633 and the biasing mechanisms 635 and 63
6 can be displaced by air pressure between the adjustment position and the retracted position.

FIG. 6 shows an example of an eccentricity adjusting device having a fine moving part 630 which is substantially the same as the fine moving part shown in FIG. More specifically, the eccentricity adjusting device shown in FIG. 6 includes an XY stage 610, a fine movement unit 630 installed on the XY stage 610, and a lens fixing unit 620 which is between them and which fixes the second lens unit L3. Have. Further, the work pressing unit 640 is arranged above the XY stage 610 and presses the holding member 50 of the first lens group L2 against the holding member 11 of the second lens group L3. The fine movement unit 630 is provided with a micrometer head 632 and an urging mechanism 635 including a spring on the opposite side thereof. Although not shown, similarly to FIG. 5, a micrometer head and a biasing mechanism having a built-in spring are arranged on opposite sides of the micrometer head in a direction orthogonal to the micrometer heads.

Next, other parts of the lens barrel will be described with reference to FIG.

In FIG. 2, the fixed mount 1 is provided with a bayonet 1a. The fixed portion 2 has three straight-moving keys 2a protruding from the inner diameter portion thereof, a guide groove 2b provided around the optical axis and functioning as an angular groove for covering the range of zooming, and a tip portion of the fixed portion 2. And a guide groove 2c provided in the.

The zoom ring 3 has a pin 3a protruding at three positions on the inner diameter side and engaged with the guide grooves 2b, and a straight-moving key 3b protruding on the inner diameter side at the front end of the zoom ring 3. Have. The adjusting member 4 is provided with a female helicoid screw 4a provided on the inner diameter side. Here, 15 is an adhesive tape for fixing the zoom ring 3 and the adjusting member 4 after the adjustment. Reference numeral 20 denotes a rubber ring which is fixed to the zoom ring 3 and the adjusting member 4 after being fixed with the adhesive tape 15.

The cam ring 5 has a straight guide groove 5a provided on the outer right side and a male helicoid screw 5b provided on the outer diameter side.
It has a cam protrusion 5c provided on the left outer peripheral portion of the cam ring 5 and a concave cam groove 5d provided on the inner diameter portion. The male helicoid member 6 includes a helicoid screw 6a provided on the outer diameter left portion and a cam follower 6 provided on the inner diameter portion.
b, 6c, and a straight guide groove 6 provided on the right side portion of the outer diameter
d and.

The holding frame 7 of the lens group L1 has a female helicoid screw 7a provided on the inner diameter portion and an engaging key 7b provided on the outer diameter right portion. The drive ring 8 has an interlocking key 8a that extends integrally with the drive ring 8 in the optical axis direction, and a drive gear 8b provided in the inner diameter portion. Lens group L
The holding member 11 for holding 3 is provided on the outer diameter portion, the interlocking protrusion 11a engaging with the cam groove 5d, and the straight advance interlocking key 1
And a guide groove 11b that engages with 0. The holding member 50 that holds the lens group 3 has an escape groove 50 b for the key 10.

According to the above structure, when the zoom ring 3 is rotated about the optical axis, the adjusting member 4 and the cam ring 5 fixed integrally with the zoom ring 3 rotate about the optical axis. Since the cam projection 5c rotates around the optical axis, the cam projection 5c
cam followers 6b and 6c that are engaged so as to sandwich c,
The male helicoid member 6 moves back and forth in the optical axis direction by the action of the rectilinear groove 6d that engages with the rectilinear key 2a of the fixed portion 2.
As a result, the holding frame 7 of the lens unit L1 that is screw-engaged with the male helicoid member 6 is also integrally zoomed in the optical axis direction. On the other hand, the holding member 11 for the lens unit L3
The holding member 50 of the lens group 2 includes the interlocking protrusion 11a that engages with the inner diameter cam groove 5d of the cam ring 5, and the linear interlocking key 1.
By the action of the guide groove 11b engaging with the cam ring 5,
When is rotated, it moves in the optical axis direction. Along with this, the lens groups L2 and L3 move in the optical axis direction by zooming.

The lens unit L1 is also a focusing lens unit,
When the holding frame 7 is rotated, the helicoid screws 7a and 6a are driven to move in the optical axis direction to perform a focusing operation. Since the engaging key portion 7b is rotationally interlocked with the interlocking key portion 8a of the drive ring 8, the drive ring 8 rotates when performing the focusing operation. The drive ring 8 is constrained by the guide groove 2c of the fixed portion 2 to be rotatable only around the optical axis. When driving with a motor and a gear for AF, the gear 8b provided on the drive ring 8 and a drive gear (not shown) rotate about the optical axis.

Next, the flange back adjustment of the zoom lens of the embodiment will be described. In the zoom lens, an error occurs in the focus position of the optical system due to manufacturing variation of parts. In order to eliminate this error, the position of the focusing lens (in this case, the lens unit L1) is adjusted in the optical axis direction by adjusting the washer and shifting the rotation limit position before the flange back adjustment (the structure is not shown). Adjust so that the focal point does not move on the wide and tele sides. If this focus movement adjustment is performed, the flange back of the entire optical system will shift. In order to adjust the flange back, according to the present invention, when the adjusting member 4 is rotated around the optical axis, the helicoid screw 5 of the cam ring engages with the helicoid screw 4a of the adjusting member 4.
b, the optical axis movement is adjusted while the cam ring 5 is rotationally interlocked with the zoom ring 3 by the action of the linear key portion 3b of the zoom ring 3 which engages with the straight groove 5a of the cam ring. Further, the cam ring 5 holds the entire optical system. As described above, the flange back adjustment can be performed by rotating the adjusting member 4. After the flange back adjustment, the zoom ring 3 and the adjusting member 4 are fixed by the adhesive tape 15, and the rubber ring 20
On the zoom ring 3 and the adjusting member 4.

As described above, according to the present invention, the protrusions corresponding to the positions provided on the respective holding members are in a state in which their tips are in contact with each other as default, and the protrusions are fitted to each other in the lens group. If there is no problem in terms of accuracy between the specific surfaces, mutual holding members are fixed with an adhesive, so that extra eccentricity adjustment is not required. Further, if the eccentricity is not within the accuracy, one of the holding members is rotated by a predetermined amount and the position of the projecting portion is shifted, so that the mutual holding members can be adjusted.

Further, according to the present invention, either the holding member for holding the first lens group or the holding member for holding the second lens group is moved during the eccentricity adjustment. There is an advantage that does not occur. Moreover, only the eccentricity can be directly adjusted, and since the lens surfaces having the centers of curvature radius in the same direction in each lens system are adjusted,
Highly accurate adjustment is possible, and the imaging performance of the lens is improved. The first and second holding members for holding the lens group are provided with contact surfaces of the respective holding members for adhering the other lens group holding member, and the contact surfaces are adhesively fixed. Therefore, it is possible to easily fix the holding member after the adjustment. Moreover, since the adhesive is temporarily fixed with a short-time curing type adhesive, the accuracy after the eccentricity adjustment is surely performed, so that the assembling workability is good. Further, by injecting the epoxy-based secondary adhesive into the groove, the first holding portion position and the second holding member can be firmly fixed. In that case, since it is temporarily fixed with a short-time curing type adhesive, when the secondary adhesive cures, there is a concern that the first and second holding members may move as the secondary adhesive cures. rare.

[0050]

As described above, according to the present invention, the eccentricity adjustment of the first lens group and the second lens group can be accurately performed.

[Brief description of drawings]

FIG. 1 is a main part sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a lens showing an embodiment of the invention.

FIG. 3 is a diagram illustrating the principle of eccentricity adjustment of the lens system.

FIG. 4 is a front view of a main part showing an embodiment of the present invention.

FIG. 5 is a schematic view of an eccentricity adjusting device.

FIG. 6 is a schematic view of a stage portion and a work fixing portion of the lens eccentricity adjusting device.

FIG. 7 is a front view of a main part showing an embodiment of the present invention (a view seen from the left side of FIG. 1).

FIG. 8 is an enlarged view of a main part of FIG.

9 is an enlarged view of a main part of FIG.

[Explanation of symbols for main parts]

 11 ... Holding member 50 ... Holding member L2 ... 1st lens group L3 ... 2nd lens group 50f, 11f ... Flange surface 11d ... Recessed groove 11c ... Notch part 50c, 11e ... Projection part

Claims (10)

[Claims] 1. A lens barrel having a first lens group and a second lens group, wherein a first holding member for holding the first lens group and a second holding member for holding the second lens group. And a first holding member and a second holding member each have a fitting portion for fitting one of them coaxially with the other, and the fitting portion includes an inner portion on an inner circumference of the outer fitting member. The inner fitting member and the outer fitting member each have an inward projecting portion projecting inwardly, an outer projecting portion projecting outwardly on the outer periphery of the inner fitting member, and There is no radial play when the tip of the protrusion and the tip of the outward protrusion contact each other, and there is no play in the radial direction when the tip of the inward protrusion does not contact the tip of the outward protrusion. A lens barrel having a structure having play. 2. The lens barrel according to claim 1, wherein a plurality of inward projections and outward projections are provided at corresponding angular positions. 3. The lens barrel according to claim 1, wherein the first holding member and the second holding member are fixed by an adhesive in a state where one of them is coaxially fitted to the other. 4. The first holding member and the second holding member according to claim 3, each having an abutting surface that abuts each other in the optical axis direction, and one of the abutting surfaces has a recess. A lens barrel, wherein the concave portion is provided with an adhesive for bonding the first holding member and the second holding member. 5. The lens barrel according to claim 4, wherein the concave portion is provided with two kinds of first concave portion and second concave portion. 6. The first holding member and the second holding member according to claim 5, wherein one of the first holding member and the second holding member has a flange, and the other of the first holding member and the second holding member has a cylindrical open end that abuts the flange. A lens barrel in which an end surface of the opening end and one surface of the flange each constitute a contact surface. 7. The first recess is provided on the end face of the opening end, and the flange has a through hole at a position facing the first recess when abutting, A lens barrel in which a second recess is provided on the outer peripheral side of the end surface of the opening end. 8. The method according to claim 4, 5, 6 or 7,
The concave portion of is filled with a first adhesive of a short-time curing type,
A lens barrel in which the second concave portion is filled with a second adhesive that is not a short-time curing type. 9. A first holding member for holding the first lens group and a second holding member for holding the second lens group, wherein one of the first holding member and the second holding member is the other. Has a fitting portion for fitting coaxially with the fitting portion, and the fitting portion has an inwardly projecting portion protruding inwardly on the inner circumference of the outer fitting member and an outer circumference of the inner fitting member. , An outwardly projecting portion that projects outwardly, and the inner fitting member and the outer fitting member are at positions where the tip of the inward projection and the tip of the outward projection contact each other. A method for adjusting the eccentricity of a lens system having a structure having radial play when sometimes there is no play in the radial direction and when the tip of the inward projection and the tip of the outward projection are not in contact with each other. In the joining portion, the first protrusion is so that the tip of the inward protrusion and the tip of the outward protrusion contact each other. With the holding member and the second holding member fitted together, the presence or absence of eccentricity of the optical axes of the first lens group and the second lens group is detected. If there is no eccentricity, this state is detected. Then, the first holding member and the second holding member are fixed with an adhesive, and when there is eccentricity, one of the first holding member and the second holding member is rotated to move the tip of the inward protruding portion and the outer side. The optical axis of the lens group in which one of the first holding member and the second holding member is fixed and the holding member of the other lens group is fixed so that the tip of the projecting portion does not abut. The optical axis of the fixed lens group and the optical axis of the other lens group are made to coincide with each other by displacing in a direction orthogonal to and the first holding member and the second holding member are fixed with an adhesive in this state. Decentering adjustment method for lens system. 10. The first holding member and the second holding member according to claim 9.
The first holding member and the second holding member are temporarily fixed with a short-time curing adhesive, and the first holding member and the second holding member are fixed with a non-short-time curing adhesive. A method of adjusting eccentricity of a lens system, which comprises fixing a holding member.