JPH10301012A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel capable of surely and simply performing the adjustment of a back focal length. SOLUTION: In a lens barrel provided with a mounting part 17 for mounting it on an external optical equipment, a first cylindrical member 110 to which the mounting part is fixed at the end part, an optical system including a focusing optical system 9, a focusing ember 12 rotated by the operation from outside and driving the focusing optical system so as to enable focusing operation, a display part 15 for displaying the positional information of the focusing optical system, an index part of another member than the display part 15 and an information displaying means displaying the positional information by the display part 15 and the index part, the index part is almost integrally composed of the mounting part 17 through the first cylindrical member 110 and the position of index part in integration with the first cylindrical member 110 is made to be variable against the display part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for use in, for example, a camera and having a back focus adjusting mechanism.

[0002]

2. Description of the Related Art The prior art will be described with reference to FIGS. FIG. 4 shows a longitudinal section of a conventional photographing lens barrel for a single-lens reflex camera. This lens barrel is used by attaching a lens mount member 17 to a corresponding body mount portion on the camera body side during photographing. The focusing ring 12 is an operation member for so-called focus adjustment,
By operating the focusing ring 12, the focusing optical system 9 is operated.
Lens 9a moves back and forth with respect to the optical axis p, and focus adjustment is performed on the subject.

As shown in FIGS. 4 and 5, a distance scale plate 1 is displayed from a distance window 14 in correspondence with a photographing distance.
5 is observable, and the shooting distance can be confirmed from the distance index 16 and the distance scale 15. The distance window 14 is a hole formed in the cylindrical body 11, and a protection cover 14 b is attached to the distance window 14 for dust and water resistance. The index member 1 on which the distance index 16 is printed is provided on the protective cover 14b.
6b is pasted. The index member 16b is configured to be substantially transparent in a range corresponding to the distance scale near the index 16, and opaque in other areas. The aperture setting ring 1 is provided on the cylinder 11 near the mount member 17.

Here, the back focus adjustment according to the prior art will be described using two examples. The back focus adjustment refers to adjusting a distance from a predetermined reference plane in the lens barrel to a film plane which is a focal plane.

A first example is a method of performing back focus adjustment with reference to a distance scale plate 15 and a distance index 16 shown in FIGS. In this method, the infinity character (∞) of the distance scale 15 is matched with the distance index 16 in the adjustment process after the lens assembly is completed, and the focus state is measured at a position corresponding to the distance on the film surface. .

The focus adjustment described above will be described with reference to FIG.
Rotation about the optical axis p corresponding to the operation 2 Rotating cylinder 1
8 is loosely fitted to the fixed cylinder 21 so as to rotate around the fixed cylinder 21 during the rotation. The cylindrical body 11 is fastened to the fixed cylinder 21 by a fixing screw 22.

The rotary cylinder 18 is provided with a cam groove 19 which engages with an interlocking pin 9c provided on the focusing lens holding frame 9b, and the focusing optical system 9 is moved along the optical axis with the rotation of the rotary cylinder 18. Move in p direction. Here, the distance scale plate 1 is
5 is fixed by a method such as bonding or screwing, and rotates in accordance with the rotation of the rotary cylinder 18. The distance scale plate 15 is visible from the outside of the cylindrical body 11 through the distance window 14, and the distance index 16 shown in FIG.
The current shooting distance can be confirmed in combination with.

The back focus adjustment in this configuration is performed by disposing an adjustment spacer 20 between the lens mount member 17 and the lens barrel 11 in the initial state of assembly as shown in FIG. Specifically, in the example of FIG. 6, the adjustment is performed by appropriately adjusting the thickness of the incorporated spacers 20a based on the measurement result of the focus state described above. In the example of FIG. 7, a single adjusting spacer ring 20b is arranged and its thickness is adjusted.

The second example is a method of performing adjustment based on the state of assembling a lens. When this adjustment method is used, it is necessary to adopt a configuration in which the relative positions of the rotary cylinder and the distance scale can be externally adjusted after the lens barrel is assembled. FIG. 8 and FIG. 9 show examples of the configuration, which are basically the same as FIG.

[0010] As shown in FIG.
8b is provided with a screw hole, and the distance scale plate 15 is attached to the fixing portion 18b using the fixing screw 3. The fixing hole 15b of the distance scale plate 15 is a long hole, and when the screw 3 is loosened, the relative position with respect to the rotary cylinder 18 can be adjusted within the range of the long hole (fixing hole) 15b.

The distance window 14 shown in FIG. 9 is sufficiently larger than the display character portion of the distance scale 15, and when the protective cover 14b of the distance window 14 is removed as shown in FIG. Through the distance window 14. The range corresponding to the distance scale near the indicator 16 of the protective cover 14b is substantially transparent, and the other is opaque. If the protective cover 14b is attached to the distance window 14 after fastening the fixing screw 3, the focus ring 12 rotates. Even if the distance scale plate 15 and the fixing screw 3 move in response to the above, the fixing screw 3 cannot be seen from outside the cylindrical body 11.

A method of adjusting the back focus when this configuration is employed will be described. After assembling the lens barrel before attaching the protective cover 14b, the focusing state at infinity is adjusted to a specified state by operating the focusing ring at a substantial position on the film surface. In this state, the position of the distance scale plate 15 is adjusted in a state where the fixing screw 3 is loosened so that the infinite position of the distance scale plate 15 and the distance index 16 coincide with each other, and then the fixing screw 3 is tightened. 14b is attached to the cylinder 11. Thus, the back focus adjustment ends.

[0013]

The above-described method of adjusting the back focus has the following problems. In the first method, measurement of the focus state, the lens mount member 1
7 and spacers 20, 20a, 2 of appropriate thickness
A series of procedures, such as replacement of the lens 0b, attachment of the lens mount member 17, and measurement of the focus state, had to be repeated, placing a heavy burden on the adjustment process and requiring much time for the adjustment.

In the second method, if the protective cover 14b is fixed to the distance window 14 by bonding or the like, readjustment becomes difficult. If the long hole 15b is provided, a space for adjustment is secured. Therefore, there is a problem that the distance window 14 becomes large.

A protective cover 114b to which an index member 16b having a distance index 16 is attached as shown in FIG.
A method in which only the distance scale plate 15 and the fixed cylinder 21 are moved relatively can be considered. In this case, the index member 16b
And through hole 1 for fixing screw 122 of protective cover 114b
11b is an elongated hole in the adjustment direction, and the relative position with respect to the fixed cylinder 21 can be adjusted in the range of the elongated hole (through hole) 111b when the screw 122 is loosened. The standard and index are shifted,
There is a problem that the appearance is not preferable.

The present invention has been made in view of the above problems, and has as its object to provide a lens barrel capable of performing back focus adjustment reliably and easily.

[0017]

In order to achieve the above object, a lens barrel according to the present invention comprises a mounting portion for mounting to an external optical device, and a first portion in which the mounting portion is fixed to an end. A cylindrical member, an optical system including a focusing optical system, a focusing member that is rotated by an external operation and drives the focusing optical system to be able to focus, and a display indicating positional information of the focusing optical system Unit, and an indicator that is separate from the display unit, and an information display unit that displays the position information using the display unit and the indicator unit. It is configured substantially integrally with the mounting portion via a first cylindrical member,
The position of the indicator is made variable with respect to the display unit integrally with the first tubular member.

According to the present invention, the relative position between the index unit and the display unit can be changed by configuring the position of the index unit so as to be variable with respect to the display unit integrally with the first tubular member. Therefore, the back focus can be easily adjusted, and the adjustment process can be greatly simplified as compared with the related art. The first cylindrical member is substantially integrated with the mounting portion, and the mounting portion changes its relative position with respect to the display portion together with the first cylindrical member during back focus adjustment. For example, the reference position between the index portion and the camera does not deviate when mounted on the camera body.

The indicator is provided on the first tubular member, the display is supported by a second tubular member, and the first tubular member and the second tubular member are connected to each other. The first tubular member and the second tubular member can be configured to be variable when the back focus is adjusted.

According to such a configuration, even when readjustment is required, the readjustment can be performed only by loosening the connection between the first tubular member and the second tubular member. Problems such as difficulty in readjustment and enlargement of the distance window do not occur.

Further, the information display means can display the photographing distance as position information by rotating the display section with respect to the index section in accordance with the rotation of the focusing member. Further, the optical device is a camera, and the optical device can be attached to the camera by a mount member as the mounting portion.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a lens barrel according to an embodiment of the present invention. FIG. 2 is a perspective view of a main part of the lens barrel, and FIG. 3 is an external view thereof. In the lens barrel shown in FIG. 1, the same parts as those in the conventional example in FIGS. 4 and 5 are denoted by the same reference numerals. In the present embodiment, the back focus adjustment mechanism is configured by making the cylinder 11 including the distance index 16 and the mount member 17 relatively rotatable with respect to the distance scale plate 15.

The lens barrel shown in FIG.
A filter lens L1 and a plurality of lens optical systems L2, L3, L4, 9, which comprise a focusing ring 12, a cylindrical body 110, and a mount member 17, and constitute an optical system of a lens barrel.
L5 is provided, the lenses L1 to L5 are supported in a fixed barrel 210, and the focusing optical system 9 is held in a holding frame 9b.

The focusing ring 12 is a so-called focus adjustment operation member, and is inside the cylinder 110 and
Is connected to a rotary cylinder 18 disposed in a concave portion 210b formed on the substantially central outer peripheral surface. The rotating cylinder 18 is loosely fitted to the fixed cylinder 210 so as to rotate with respect to the outer peripheral surface of the fixed cylinder 210 during the rotation. The mounting member 17 is the cylinder 1
10 is fixed to an end face by a fixing screw 2. An aperture setting ring 1 is provided around the cylinder 110 near the mount member 17.
Is arranged.

The fixed cylinder 210 has a small diameter in the direction of the mount member 17, and the small diameter portion including the recess 210b is covered with the cylinder 110. The cylindrical body 110 has a step 11a formed so as to oppose the end surface 210a of the small diameter portion of the fixed cylinder 210, and the inner vertical surface 110 of the step 11a.
a is in contact with the end surface 210a of the fixed cylinder 210. Cylinder 1
As shown in FIG. 2, a plurality of through holes 11b are formed in the ten step portions 11a, and the through holes 11b are formed as long holes extending in the circumferential direction around the optical axis p. Fixed screw 2
2 is inserted into the through hole 11b and the end surface 21 of the fixed cylinder 210 is
The cylinder 110 and the fixed cylinder 210 are fastened by being screwed into the screw holes formed in Oa.

The cylinder 110 and the mount member 17 are fixed to the fixed cylinder 21 with the fixing screw 22 loosened so that the cylinder 110 and the mount member 17 can rotate integrally around the lens optical axis p.
The position relative to 0 can be adjusted within the range of the elongated hole 11b. As shown in FIG. 2, the elongated hole 11 b extends in the circumferential direction, and the circumferential distance is configured to be larger than the circumferential distance necessary for adjusting the distance scale 15 and the distance index 16. .

The rotary barrel 18 is provided with a cam groove 19 which engages with a pin 9c provided on the focusing lens holding frame 9b. A focusing optical system including the lens 9a with the rotation of the rotary barrel 18 is provided. Reference numeral 9 moves in the optical axis p direction. Thus, by rotating the focusing ring 12, the rotating barrel 18 is rotated, and the focusing optical system 9 is moved in the direction of the optical axis p, whereby focusing of the lens barrel can be performed.

A distance scale 15 is fixed to the rotary cylinder 18, and the distance scale 15 rotates in accordance with the rotation of the rotary cylinder 18. The cylindrical body 110 covers the distance scale plate 15.
The cylindrical body 110 has a distance window 14 corresponding to the distance scale plate 15. This distance window 14
The distance scale 15 can be viewed from the outside of the cylindrical body 110 through the through hole. An index member 16b including a distance index 16 similar to the index member shown in FIG. 5 is provided in the distance window 14 of the cylinder 110, and the current shooting distance is determined by a combination of the distance scale 15 and the distance index 16. Can be confirmed. Distance window 1
4, a protection cover 14b for the purpose of dustproofing and waterproofing having the same configuration as that of FIG. 4 is attached so as to cover the index member 16b.

The back focus adjustment for the lens barrel having the above configuration will be described. First, the focusing state at infinity is adjusted to a specified value by operating the focusing ring 12 at a position corresponding to the film surface. The focusing optical system 9 of this lens is set in advance so that the focusing lens group can be moved farther and closer to the design value infinity position and the closest position. In this state, after the fixing screw 22 shown in FIGS. 1 and 2 is loosened, the index member 1 having the distance index 16 in the distance window 14 is provided.
6b is rotated relative to the fixed cylinder 210 and the distance scale plate 15 so that the distance index 16 matches the infinite position (位置) of the distance scale plate 15,
After the distance scale plate 15 and the distance index 16 are aligned, the fixing screw 22 is tightened. In this way, the back focus adjustment ends.

In this adjustment, the focusing ring 1 is used to prevent the distance scale 15 from being accidentally moved during the adjustment.
2 is preferably fixed to the fixed cylinder 210.

As described above, in this embodiment, the cylinder 110 including the distance index 16 and the mount member 17 are moved from the outside of the lens to the focusing optical system 9, the fixed cylinder 210, and the distance scale plate 15. , So that a series of operations such as measurement of the focus state, removal of the mount part, replacement of the spacer, attachment of the mount part, and measurement of the focus state are performed as in the method described in the first related art. Can be omitted, and the adjustment process can be greatly simplified.

Further, even if re-adjustment such as repair or overhaul is required, the state can be re-adjusted only by loosening the screw 22 for fastening the rotary cylinder 210 and the cylinder 110. If the distance window 14 is fixed by a method such as bonding as described above, re-adjustment becomes difficult, and problems such as an increase in the size of the distance window to secure a space for adjustment do not occur. Further, the relative position with respect to the focusing optical system 9 and the distance scale plate 15 changes in a state where the cylindrical body 110 as an adjusting member in which the distance index 16 is integrally arranged and the mount member 17 is integrated. It is also possible to solve the problem that the index and the reference position of the camera are shifted when mounted on a camera body or the like. Further, since it is possible to give a margin to the diameter and length that can be adjusted as compared with other adjustment methods, there is an effect that accurate adjustment can be easily performed.

In this embodiment, the lens barrel is mounted on the camera. However, the lens barrel according to the present invention can of course be mounted on another optical device.

[0034]

According to the present invention, it is possible to provide a lens barrel capable of performing the back focus adjustment reliably and easily.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a lens barrel according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the lens barrel shown in FIG.

FIG. 3 is an external view of the lens barrel shown in FIG.

FIG. 4 is a longitudinal sectional view of a conventional lens barrel.

FIG. 5 is an exploded perspective view showing a distance window portion in a conventional lens barrel.

FIG. 6 is a perspective view showing a back focus adjusting mechanism of the conventional lens barrel shown in FIG.

FIG. 7 is a perspective view showing another back focus adjusting mechanism of the conventional lens barrel shown in FIG.

FIG. 8 is a longitudinal sectional view of another conventional lens barrel.

9 is an external view of the lens barrel shown in FIG.

FIG. 10 is an exploded perspective view showing another distance window portion in a conventional lens barrel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Aperture value setting ring 2 Mounting part mounting screw 9 Focusing optical system 9a Focusing lens 9b Focusing lens holding frame 9c Interlocking pin 110 Tube (first cylindrical member) 12 Focusing ring 14 Distance window 14b Distance window protection Cover 15 Distance scale plate 16 Distance index 16b Index member 17 Mount member 18 Rotating cylinder 19 Cam groove 20, 20a, 20b Adjustment spacer 210 Fixed cylinder (second cylindrical member) 22 Fastening screw

Claims (5)

[Claims] 1. A mounting section for mounting to an external optical device, a first cylindrical member to which the mounting section is fixed at an end, an optical system including a focusing optical system, and an operation from outside A focusing member that rotates to drive the focusing optical system so as to be able to focus, a display unit that indicates position information of the focusing optical system, and an indicator unit that is a member separate from the display unit, A lens barrel comprising: a unit and information display means for displaying the position information by the index unit, wherein the index unit is substantially integrated with the mounting unit via the first cylindrical member, A lens barrel, wherein the position of the index portion is made variable with respect to the display portion integrally with the first cylindrical member. 2. The lens barrel according to claim 1, wherein a back focus is adjusted by changing a relative position between the index section and the display section. 3. The indicator section is provided on the first tubular member, the display section is supported by a second tubular member, and the first tubular member and the second tubular member are connected to each other. 3. The lens barrel according to claim 2, wherein the lens barrel is fastened to allow a relative position between the first tubular member and the second tubular member to be variable during back focus adjustment. 4. The lens barrel according to claim 3, wherein the information display means displays a shooting distance as position information by rotating the display unit with respect to the index unit in accordance with rotation of the focusing member. 5. The lens barrel according to claim 1, wherein the optical device is a camera, and the optical device is mounted on the camera by a mount member as the mounting portion.