JP3493809B2 - Lens barrel and lens system eccentricity adjustment method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
And a lens barrel having the second lens group, and a decentering adjustment method for a lens system having the first lens group and the second lens group.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for adjusting the eccentricity of a lens, Japanese Utility Model Laid-Open No. 5-36410 and JP-A-6-265 are known.
Some are described in Japanese Patent No. 766. In the former device, a proper play is provided on the lens outer diameter and the inner peripheral surface of the lens holding member, and a plurality of adjusting screws abut against the outer diameter portion of the lens from the outer peripheral direction of the holding member, thereby providing a plurality of lenses. Adjust the lens eccentricity. In the latter device, the parallel light transmitted through the first and second lens systems is used to obtain the correction amount of the centering by performing image processing on the imaging performance to directly adjust one lens system. Adjust the amount of correction with a tool and glue.

[0003]

However, in the above prior art, in the adjusting screw method of Japanese Utility Model Laid-Open No. 5-36410, since the lens is directly pushed, the adjustment is performed on the surface opposite to the body-attached surface of the lens. Taore will occur.
In addition to this, the presser ring is loosened during the lens adjustment and is tightened again after the adjustment, so that the lens is likely to move when the presser ring is tightened. On the other hand, as described in Japanese Unexamined Patent Publication No. 6-265766, the correction amount of the centering is obtained by image-processing the image forming performance by utilizing the parallel light transmitted through the first and second lens systems. , The method of adhering one lens system directly by the adjustment jig by the correction amount and adhering it is possible only when the lens to be adjusted can be moved directly by the adjustment jig. Adjustment is difficult in the case of a lens.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a first lens group and a second lens group which are required to mutually adjust their optical axes. An object of the present invention is to provide a lens barrel capable of accurately adjusting the eccentricity.

Another object of the present invention is to provide a method of adjusting the eccentricity of a lens system, which is capable of accurately adjusting the eccentricity of a lens system having a first lens group and a second lens group. is there.

[0006]

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. a first holding member for holding the, and a second holding member for holding the second lens group, the first holding member and the <br/> second holding member, together with the optical axis parallel to the direction Each has an abutting surface to abut, and one of the corresponding abutting surfaces,
A deep recess and a shallow recess are provided independently,
In each of the recesses and the shallow recess, the adhesive for bonding the said first holding member and the <br/> second holding member are filled Tei
A lens barrel, wherein Rukoto is provided.

[0007]

[0008] The first holding member and the second holding member, for example, one of them has a flange, those of the other has a said flange abutting cylindrical open end of the open end The end surface and the flange may respectively form a contact surface. For example, the shallow recess can be provided on the end face of the opening end. On the other hand, the flange may be provided with a through hole at a position facing the shallow recess when contacted .

Furthermore, the outer peripheral side of the end surface of the open end, the
A deep recess may be provided. This deep
The concave portion may be provided in a stepped shape on the outer peripheral side of the end surface of the opening end.

According to another aspect , the first lens group
A lens barrel having a first lens group and a second lens group,
Holding member for holding the second lens group, and the second lens group
A second holding member for holding the first holding member and
The second holding members contact each other in a direction parallel to the optical axis.
Each has a contact surface, and one of the contact surfaces is
First recess, a second recess is provided, the said first recess, is filled with a first adhesive for a short time curing, the the second recess, the second is not a short-curable A lens barrel is provided which is filled with two adhesives.

According to another aspect of the present invention in order to achieve another object of the present invention, there is provided a first method for adjusting an eccentricity of a lens system having a first lens group and a second lens group.
Of the first holding member and the second holding member, and the second lens group is held by a second holding member independent of the first holding member. The lens group of is fixed, the holding member of the other lens group is displaced in a direction orthogonal to the optical axis of the fixed lens group, the fixed lens group and the optical axis of the other lens group are aligned, In this state, the first holding member and the second holding member are temporarily fixed with a short-time curable adhesive, and the first holding member and the second holding member are further fixed with a non-short-time adhesive. There is provided a method for adjusting the eccentricity of a lens system, characterized in that

[0012]

According to the present invention, the first lens group is held by the first holding member, and the second lens group is held by the second holding member independent of the first holding member. As a result, the optical axes of the first lens group and the second lens group can be adjusted by relatively displacing the first holding member and the second holding member. The optical axis adjustment is performed by fixing one lens group of the first holding member and the second holding member and displacing the holding member of the other lens group in a direction orthogonal to the optical axis of the fixed lens group. , By making the optical axes of the fixed lens group and the other lens group 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. In addition, a holding member that holds the first lens group, and a second
Since either one of the holding members for holding the lens group is moved during the eccentricity adjustment, deterioration of the lens system rotation 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.

Thus, by 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.

[0015]

EXAMPLES Examples 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 for 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 unit L2 and the lens unit L3 holds the first holding member 50 for holding the first lens unit L2 and the second lens unit L3. The second holding member 11 is provided. In addition, the lens unit L2
Is composed of lenses G4 and G5. Lens group L
3 is composed of lenses G6 and G7. The lens groups L2 and 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 outer diameter of the cylindrical body 502 is smaller than the inner diameter of the connecting portion 113 by 2c. That is, a gap c exists between the outer circumference of the tubular body 502 and the inner circumference of the connecting portion 113, and the eccentricity adjustable range of the play (clearance) 2c is set. Here, in the present embodiment, the value of c is, for example, 0.
It is 1 mm.

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 holding members 50 and 11 are fixed by using two kinds of adhesives. That is, a short-time curable adhesive called an instant adhesive, for example, an ethyl cyanoacrylate-based adhesive and a non-short-time adhesive, for example, an epoxy-based secondary adhesive are used. Groove 1
The short-time curing type adhesive 101 is dropped onto the 1d through the through hole 50a. The notch 11c is filled with an epoxy-based secondary adhesive 100. As a result, temporary fixing after eccentricity adjustment is reliably performed with the short-time curing type adhesive 101. In addition, when the secondary adhesive is cured, the first holding member 50 and the second holding member 11 are separated from each other by the secondary adhesive 100.
I am trying not to move with the hardening of. Then, the epoxy-based secondary adhesive 100 can maintain the strength after the lens is assembled.

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 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 to press the holding member 50 of the second lens group against the third lens group holding member 11. The fine movement unit 630 is provided with a micrometer head 632.
And a biasing mechanism 6 with a built-in spring on the opposite side.
And 35 are arranged. 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 thereof and engaged with the guide grooves 2b, and a straight-moving key 3b protruding on the inner diameter side of the front end portion 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 includes a straight guide groove 5a provided on the outer right side, 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 unit 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, 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 the deterioration of the system does not occur. Moreover, only the eccentricity can be adjusted directly, and the lens surfaces having the same radius of curvature center in the same direction within each lens system are adjusted, which enables highly accurate adjustment and improves the imaging performance of the lens. To do. 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.

[0038]

According to the present invention, it is possible to accurately perform decentering adjustment of the first lens group and the second lens group, which require mutual adjustment of the optical axes.

[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 present 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 for a lens.

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

[Explanation of symbols for main parts]

11 ... Second lens unit L2 holding member 11f ... Open end face 50 ... First lens unit L3 holding member 50f flange surface L2 ... the first lens group L3 ... second lens group 11d ... concave groove 11c ... Notch

Claims (9)

(57) [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. with the door, the first holding member and the second holding member, the optical axis and flat
Have contact surfaces that contact each other in the running direction,
One of the contact surfaces has a deep recess or a shallow recess.
Are provided independently of each other, and the deep recess and the shallow recess are aligned with each other.
To respectively, the lens barrel adhesive for bonding the said first holding member and the second holding member is characterized in that it is filled. 2. The lens barrel according to claim 1, wherein the deep recess has a depth 20 times or more that of the shallow recess.
A lens barrel characterized by that . 3. The register according to claim 1,
In lens barrel, the first holding member and the second holding member, one of them having a flange, those of the other has a said flange abutting cylindrical open end of the open end this to the one surface of the end face and the flange constitutes the abutment surface, respectively
And lens barrel. 4. The lens barrel according to claim 3, the end face of the open end, this said shallow recess is provided
And lens barrel. 5. A lens barrel according to claim 4, said flange, at a position opposed to the shallow recess when in contact with the lens barrel and having a through-hole. 6. at the lens barrel according to any one of claims 3 to 5, on the outer peripheral side of the end face of the open end, a lens barrel, wherein the deep recess is provided . 7. The lens barrel according to claim 6, wherein the deep recess, the lens barrel, characterized in that provided in the stepped on the outer peripheral side of the end surface of the open end. 8. A first lens group and a second lens group
In the lens barrel, the first holding member holding the first lens group and the second lens
And a second holding member for holding the lens group, wherein the first holding member and the second holding member are in a direction parallel to the optical axis.
Have contact surfaces that contact each other, and
The first recess and the second recess are provided on either of the surfaces.
Is, the in the first recess, is filled with a first adhesive for a short time curing, the the second recess, the second adhesive is not a short curing is filled Characteristic lens barrel. 9. A method of adjusting eccentricity of a lens system having a first lens group and a second lens group, wherein the first lens group is held by a first holding member, and
This lens group is held by a second holding member independent of the first holding member, one of the first holding member and the second holding member is fixed, and the holding member of the other lens group is fixed. Displace in a direction orthogonal to the optical axis of the fixed lens group so that the optical axis of the fixed lens group and the optical axis of the other lens group coincide with each other. A method for adjusting eccentricity of a lens system, which comprises temporarily fixing a member and a second holding member, and further fixing the first holding member and the second holding member with an adhesive that is not a short-time curing type.