JPS6118910A - Lens barrel - Google Patents

Abstract

PURPOSE:To adjust the focus position of the lens barrel which incorporates a floating system by fixing a helicoid member adjustably in the optical-axis direction to a fixed frame member during focusing operation. CONSTITUTION:The 1st lens frame 35 united with the focus frame of the zoom lens barrel is coupled with the helicoid member 40 through a helicoid screw, and this helicoid member 40 is fixed to the frame member 33 with an adjusting screw 54 adjustably in the optical-axis direction. A floating frame 58 which supports a floating lens 57 is fitted movably in the 2nd lens frame 43, and a guide pin 59 implanted in the outer periphery of the floating frame 59 is fitted in the fork groove of a transmission arm 55 for floating fixed to the lens frame 35. The lens frame 35 does not rotate during the adjustment of the helicoid member 40, so the floating frame 58 is stationary to the lens frame 43 and the floating lens 57 does not move associatively.

Description

Detailed Description of the Invention (Technical Field) The present invention provides a lens barrel, more specifically, an adjustment function for correcting a shift in the focus position during assembly, when zooming while keeping the focus. , it is possible to focus on infinity at all focal lengths. However, in reality, due to the precision of parts such as the lens frame and lens, or the precision of the M-crossing, the focus position may shift due to zooming if the lens is simply assembled.

Currently, there are two ways of thinking regarding adjustment of the focus position. One is the focus frame for adjusting the focus.For example, it should be able to rotate further away than infinity, so that even if the focus position shifts due to zooming, the focus frame can be used to refocus. What I did.

The other is a system in which the parts used for focusing in the optical system of the zoom lens barrel are made adjustable once during assembly, thereby eliminating movement of the focus position during zooming. be. However, the former
Since the focus position shifts due to zooming, a focus position adjustment method that adopts the latter idea will be described here.

FIG. 14 is a sectional view showing an example of a conventional lens barrel. The lens barrel 1 is a zoom lens barrel, and the fixed frame 2
The lens frame 5 supporting the first lens group 4 is attached to the helicoid screw 6 on the outer periphery of the tip of the helicoid frame 3 fitted on the outer periphery of the helicoid frame 3.
A focus frame 8 is fixed to the outer periphery of the lens frame 5 by an adjustment screw 7.

Since the guide bin 9 installed in the fixed frame 2 is fitted into the optical axis OK G straight groove 3a of the helicoid frame 3, the helicoid frame 3 does not rotate when the focus frame 8 is rotated. Instead, the lens frame 5 is rotated integrally with the focus frame 8 and moved in the front-rear direction along the optical axis 0 by the helicoid screw 6. Note that the notch 8a of the focus frame 8
A stock hinge 11 embedded in the helicoid frame 3 is disposed within the helicoid frame 3 for regulating the rotation range of the focus frame 8 from close range to infinity. The inner circumference of the fixed frame 2 has a second
A second lens frame 13 holding a lens group 12 is fitted therein, and a guide bin 14. which is implanted in the helicoid frame 3 is fitted therein.
The guide bins 15 installed in the second lens frame 15 and passing through the relief holes 2b on the identification frame 2 are connected to the cams 16a of the zoom frame 16, which are rotatably provided.

16b IC is fitted. The guide bin 17 implanted in the second lens frame 13Vc is fitted into the straight groove 2a formed on the optical axis 0 of the fixed frame 2. For this reason, the zoom frame 16 is
b) When moving, the helicoid frame 3 moves back and forth along the optical axis 0 according to the shape of the cam groove 16a integrally with the first lens frame 5, and the second lens frame 13 moves along the light 4110 according to the shape of the cam groove 16b. move back and forth. An aperture ring 19 is rotatably fitted to the rear outer periphery of the fixed frame 2, and an intermediate frame 20 is fixed to the rear end of the fixed frame 2 with a set screw 21. The mount 23 is fixedly mounted.

In this way, in the zoom lens barrel 1, by rotating the zoom frame 16, the helicoid frame 3 and the second lens frame 13 are moved back and forth in the optical axis direction to change the focal length, and the focus frame 8 is moved back and forth in the optical axis direction. By rotating it...
The distance control is performed by moving the lens frame 5 back and forth in the optical axis direction with respect to the helicoid frame 3.

During assembly work, in order to eliminate movement of the focus position due to zooming, the adjustment screw 7 is loosened to make the focus frame 8 and the lens frame 5 independent, and then the focus frame 8 is rotated. The positional relationship between the first lens frame 5 and the second lens frame 13 in the optical axis direction is adjusted by rotating only the first lens frame 5 while making sure not to After the adjustment, the adjustment screw 7 is tightened again to unite the lens frame 5 and the focus frame 8. By doing this, errors in the optical system caused by precision of parts of the lens frame and lenses of the zoom lens barrel 1 and assembly precision are eliminated.

However, in the case of the method for adjusting the focus position leg in the zoom lens barrel 1, since the first lens frame 5 always rotates with adjustment, the rotational component of the first lens frame 5 is used as information to adjust the focus position to other lenses. This method cannot be applied to a lens barrel that employs a floating system (near distance correction mechanism) that moves the floating lens for five reasons, since the position of the floating lens shifts.

(Objective) In view of the above-mentioned conventional drawbacks, an object of the present invention is to have a focus position adjustment function for correcting the focus position, and to
To provide a lens barrel capable of accurately transmitting a rotational component of a focus lens for a 7-ring lens to a 74-ring lens.

(Summary) The lens barrel of the present invention performs focusing by rotating a focus frame connected to a helicoid member with a helicoid screw, and also moves a fluting lens in the optical axis direction by a rotational component of the focus frame. In the lens barrel with a built-in 70-ting system, the helicoid member is fixed to an immovable frame member during focusing so as to be freely adjustable in the optical axis direction, and the focus position during assembly is adjusted according to the man 1. In this case, the positional relationship between the helicoid member and the frame member is adjusted.

(Example) The present invention will be explained below based on the following embodiments.

FIG. 2 is a sectional view of a lens barrel showing a first embodiment of the present invention. In this zoom lens barrel 51, the focus frame 38 is integrated with the second lens frame 43 supporting the first lens group 54 by means of a fixing screw 37, and is formed on the rear outer periphery of the second lens frame 43. The helicoid screw 35a has a helicoid screw 40a of the helicoid member 40.
are screwed together. As shown in the first picture, this helicoid member 40 has three protrusions 4 [IB] integrally formed at equal angular intervals on the inner wall of the link part 40^, and the protrusions 40
The helicoid screw 40g is formed on the inner peripheral surface of B. A stopper bin 4 is provided on the outer periphery of this helicoid member 40.
1 is planted, and the stopper bin 41 is the focus frame 58.
was formed on the inner periphery of It is disposed within a notch 38a for regulating the rotation range of the focus frame 38 from close range to infinity.

The tip portion of the frame member 33 is fitted into the inner periphery of the ring portion 40A of the helicoid member 40, as shown in FIG. That is, at the tip of this frame member 33, a notch 53b having a width comparable to the ring of the protrusion 40B is formed at a position facing the protrusion 40B of the helicoid member 40,
This notch 35b fits into the protrusion 40B. Therefore, when the frame member 33 and the helicoid member 40 are fitted together, the helicoid member 40 is integral with the frame member 33 in terms of rotational force, and is movable in the direction along the optical axis 0. It has become. Further, as shown in FIG. 1, an elongated hole 40b is formed in the ring portion 40A of the helicoid member 40 at a position offset from the protruding portion 40B in the direction along the optical axis O. The helicoid member 40 and the frame member 3 are connected by an adjustment screw 54 that passes through the frame member 33 and screws into the frame member 33.
3 are integrally fixed.

Therefore, when adjusting the position of the helicoid member 40 in the optical axis direction with respect to the frame member 33, the adjustment screw 54 is loosened, and after adjustment, the screw 54 is tightened to integrate the two members.

The frame member 36 has a rectilinear groove 55a formed in its inner peripheral surface into which the guide bin 39 implanted in the fixed frame 32 fits, and a cam groove 55a of the zoom frame 46 in the rear part of the outer peripheral surface.
A guide bin 44 that fits into 68' is installed,
Therefore, when the zoom frame 46 is rotated, the frame member 33 moves in the optical axis direction according to the shape of the cam f1146a.

A second lens frame 43 holding a second lens group 42 is fitted into the inner periphery of the fixed frame 32 . This second lens frame 45
K is a straight groove 528 formed on the inner peripheral surface of the fixed frame 52.
A guide bin 47 that fits K is implanted on the outer periphery of its front end, and a guide bin 45 that passes through the escape hole 32b of the fixed frame 32 and fits into the cam groove 46b of the zoom frame 46 is implanted. Therefore, when the zoom frame 46 is rotated, the second lens frame 43 moves in the optical axis direction according to the shape of the cam groove 46b.

One end of a 74-ting transmission arm 55 is fixed to the rear end surface of the first lens frame 35 with a set screw 56. This 70-ting transmission arm 55 has an optical axis OVc,
They extend rearward in parallel, and the other end passes through the through hole 45a of the second lens frame 43 and reaches the rear of the second lens frame 43. As shown in FIG. 3, a fork groove 55a is formed at the other end of the transmission arm 55. As shown in FIG. Furthermore, a floating lens 57 is provided on the rear inner circumference of the second lens frame 43.
The 74-ting frame 58 supporting the
A guide pin 59 installed on the outer periphery of the floating frame 58 is fitted into the 74-ring cam hole 43b formed at the rear of the second lens frame 43 and the fork groove 55aK.

Further, on the rear outer periphery of the fixed frame 32, as shown in FIG.
An aperture ring 49 is rotatably fitted together, and an intermediate frame 50 is fixed to the rear end of the fixed frame 32 with a set screw 51.
A mount member 53 is fixed to 0 by a set screw 52. Note that since a well-known diaphragm mechanism can be applied, the operation will be explained with reference to an expanded plan view of each lens frame of the zoom lens barrel 31 shown in FIG. 4 to simplify the illustration. The state shown in Fig. 2.4 is a telephoto (T
) state. In this telephoto (T) state, the frame member 33 has moved completely rearward due to the relationship between the cam groove 46B and the guide pin 44, and the guide bin 39 on the fixed frame 32 is located at the front end of the straight groove 35a. This frame member 33 is connected to the helicoid member 40! M] Since it is integrated by the adjustment screw 54, the helicoid member 40, this helicoid member 40
The second lune frame 35 screwed together with the helicoid screws 40a and 55a and the floating transmission arm 55 fixed to the WJ lune frame 35 are in a state of being moved rearward integrally with the frame member 33. Further, due to the relationship between the cam f#46b and the guide pin 45, the second shutter frame 43 has moved completely forward, and the guide bin 47 is located at the front end of the straight groove 62a on the fixed frame 32.

When the zoom frame 46 is rotated counterclockwise from the above-mentioned telephoto state to zoom to the wide-angle (W) side, the frame member 33 moves forward due to the relationship between the guide bin 44 and the cam @ 46a. Helicoid member 40. The third lens frame 35 and the floating transmission arm 55 also move forward. Further, the second lens frame 43 moves rearward due to the relationship between the guide pin 45 and the cam signal 46b.

In addition, the state shown in FIG. 2.4 above is the focus frame 38.
is rotated clockwise to focus on infinity (oQ). That is, the focus frame 38 is set to
When the focus frame 38 is rotated in the direction of
The lune frame 35 rotates clockwise, but since the helicoid member 40 fits into the notch 35b of the frame member 33 and is restricted from rotating, at this time, the lune frame 35 is rotated clockwise by the helicoid screw 55m. Due to the relationship between Rotation in the direction of the hour hand is restricted. When the 70-ring transmission arm 55 integrated with the second lens frame 43 is fully rotated clockwise, the 70-ring #f 55 of the transmission arm 55 is fully rotated.
The guide pin 59 fitted into the lens frame 70 is at an infinite position at one end of the floating cam hole 45b on the second lens frame 46, and therefore the 70-teating frame 58 is also at an infinite position.

Then, when the zoom frame 46 is zoomed from the telephoto state to the wide-angle state as described above while the focus frame 38 remains in the infinity position, the floating transmission arm 55 moves forward together with the lens frame 35. move,
Since the second lens frame 43 moves rearward, the guide bin 59 of the 70-ting frame 58 is aligned with the fork groove 55a K f
Ej moves backwards.

The guide pin 59 during this zooming is attached to the second lens frame 43.
ftN2 lens frame 43.
The position of the floating frame 58 relative to the frame 58 is constant.

When the focus frame 38 is rotated counterclockwise to change from the infinity state to the close-up state, the floating transmission arm 55 of the lens frame 35 is also rotated counterclockwise and simultaneously extended forward, and the notch portion It stops at the position where the other end of 58a abuts against stopper bin 41. Then, the guide pin 59 rotates together with the transmission arm 55, and
It moves forward into the fork groove 55a and reaches a position close to the other end of the 70-ting cam groove 43b of the second lens frame 43, so at this time, the 70-ting frame 58 moves forward. 43, and short distance correction is performed.

By the way, the zoom lens barrel 31 that operates as described above
However, as described above, simply assembling the lens will cause a shift in the focus position due to zooming, so it is necessary to correct this shift. Therefore, the above zoom lens barrel 3
During the assembly work 1, the helicoid member 40
and the adjustment screw 54 that integrally fixes the frame #33.
Loosen it once. In this state, the helicoid member 40 is movable in the optical axis direction independently of the frame member 33, so by moving the focus frame 38 back and forth, the first lens frame 35 is moved together with the helicoid member 40 in the optical axis direction. Move it back and forth. For example, the relationship between the first lens frame 35 and the frame member 33 in the state shown in FIG. 5(A) is changed from the state shown in FIG. 5(B) to the state shown in FIG. Hole 40
Adjustment is possible within the length range of b.

Therefore, the second lens frame 35 is reset to a position where the focus position does not move even when the second lens frame 43 zooms, and then the helicoid member 40 and the frame member 33 are fixed by tightening the adjustment screw 54. and integrate. When adjusting the movement of the first lens frame 35 in the optical axis direction, since the second lens frame 35 does not rotate IJh, the floating transmission arm 55 also moves smoothly in the optical axis direction without any automatic movement. For this reason.

The guide pin 59 on the floating frame 58 slides within the seven-oak groove 55a of the transmission arm 55, and since no force is applied to the guide pin 59 in the direction of automatic movement, this adjustment movement of the focus position is At times, the floating frame 58 remains stationary relative to the second lens frame 43. Therefore, after assembly, movement of the focus position due to zooming is adjusted, and short distance correction will not be disturbed. Note that the helicoid member 40 with respect to the frame member 33
After correcting the shift in focus position due to zooming by adjusting the optical axis direction of It is adjustable.

In the above embodiment, the helicoid member 40, which integrally has a plurality of protrusions 40B with helicoid threads 40a formed on the inner periphery, is fitted onto the outer periphery of the frame member 33. The relationship with the frame member may be configured as shown in FIGS. 6 and 7, for example. That is, in the second embodiment shown in FIG. 6.7, the helicoid member 7
0 has a helicoid screw 70a formed on the entire inner periphery of the short cylinder, which screws into the helicoid screw 35a of the first lens frame 35, and a cylindrical frame member 73 is fitted on the outer periphery of this helicoid member 70. ing. Six elongated holes 75C parallel to the optical axis O are formed in this frame member 73 at equal angular intervals, and each of these elongated holes 75c! # After the adjustment screws 74 are fitted, these screws 74 are screwed into the helicoid member 70. Further, a stopper pin 41 located within the notch 38a of the focus frame 38 is implanted on the outer periphery of the frame member 73, and a guide pin 39 implanted in the fixed frame 52 is further implanted on the inner periphery of the frame member 75 behind the stopper bin 41. A straight groove 73a that fits is provided. Therefore, this second embodiment also operates in the same manner as the first embodiment, and in particular,
When adjusting the movement of the focus position due to zooming, loosen the adjusting screw 74 and adjust the position of the helicoid member 700 in the optical axis direction with respect to the frame member 73.
4 to fix the frame member 73 and the helicoid member 70, the above adjustment is completed without imparting a rotational component to the 70-ting transmission arm 55.

Further, the relationship between the helicoid member and the frame member is as follows:
It can also be configured as shown in FIG.

That is, in the third embodiment shown in FIGS. 8 and 9, the edge fitting member 80 having a helicoid screw 80a that is screwed into the helicoid screw 35a on the outer periphery of the second lune frame 35 is made of a piece, and Three pieces are arranged at equal angular intervals around the outer circumference. These three helicoid members 80 are the frame member 8
They fit into four guide portions 83b formed at equal angular intervals on the inner wall of 3 and are slidable in the direction along the optical axis OK. Then, the guide recess 8 of the frame member 83. From the outside into the long hole 85C formed along the longitudinal direction in the center of b! ! An adjustment screw 84 is fitted, and the helicoid member 80 is fixed to the guide recess 83b by the same screw 84.

Therefore, in this embodiment as well, when adjusting the movement of the focus position by zooming, loosen the adjustment screw 84 and move the helicoid member 80 on the guide recess 83c in the optical axis direction to select the optimum position. It is only necessary to identify the screw 84 mentioned above. In this embodiment, the helicoid member 80 may be a small piece, so the zoom lens frame is @Sf.

Further, Figure 11g1() shows the configuration of the 70-ting transmission arm in the zoom lens barrel of the fourth embodiment of the present invention, and Figure @11 shows the configuration of the relationship between the helicoid member and the frame member. This shows that.

Since the focal length of a zoom lens barrel changes with zooming, in order to perform highly accurate 70-ting, it is desirable to change the amount of 70-ting according to zooming. In a zoom lens barrel that employs such a highly accurate floating system, the 74-ring transmission arm 95 fixed to the lens frame 35 (see Figure 2) is oriented in the direction along the optical axis 0. Seven oak grooves 95a are formed which are inclined by an angle θ. Now, in the telephoto (T) state, in the infinity (oo) state where the No. 1 lens frame 35 has completely rotated clockwise, the guide bin 59 on the floating frame 58 fitted in the 7 oak groove 95a of the transmission arm 95 is also Rotate clockwise, 7
Although it is located at the position T- at one end of the zeroing cam hole 43b, as described in the operation of the zoom lens barrel 31 of the first embodiment, the % focus frame 38 (see FIG. 2)
to rotate the second run frame 35 in the counterclockwise direction,
When the helicoid screw 90a and the helicoid screw 55a are used to feed the 7-keying transmission arm 495 to a close position, the 7-keying transmission arm 495 also rotates counterclockwise and moves forward. 45b and reaches the position ToK. Further, when zooming is performed toward the wide-angle (W) side from the state where the guide bin 59 is at position T-, the second lens frame 35 moves forward and
Since the lens frame 43 moves backward along the optical axis OK, the guide bin 59 is pushed by the side edge of the fork groove 95a and moves the 70-ting cam hole 43b to position W6o.
Move up to. From this wide-angle side infinity state, when the seventh focus frame 38 is operated and the second lens frame 65 is rotated counterclockwise in the direction of the hour hand to a close state, the guide bin 59
-Ting transmission arm A95)/l, therefore, moves within the 70-Ting cam hole 43b and reaches the position Wo at the other end of the cam hole 43b.

In this way, the amount of focusing that changes depending on the distance also changes with zooming, and in such a zoom lens barrel, when adjusting the movement of the focus position due to zooming, the lens frame If the guide bin 65 is moved in the direction along the optical axis 0, the guide bin 59 will move inside the 70-ting cam hole 43b and the amount of loading will be incorrect.To avoid this, In this case, a helicoid member 90 and a frame member 93 configured as shown in FIG. 11 are used.

The helicoid member 90 shown in FIG. 11, like the helicoid member 40 in the first embodiment, has three protrusions 90B integrally formed on the inner wall of the ring portion 90 at equal angular intervals. A helicoid screw 90a that is screwed into the helicoid screw 55a of the first lens frame 35 is formed on the inner periphery of the portion 90B, but this protrusion portion 90B is inclined at an angle θ' with respect to the direction parallel to the optical axis 0. It is provided. Therefore, the frame member 93 fitted into this helicoid member 90
Also, the three notches 95b formed at equal angular intervals on the # end are at an angle θ with respect to the direction parallel to the optical axis O.
It is inclined by I. This angle θI corresponds to the inclination angle θ of the seven oak grooves 95a of the transmission arm 95. Then, the ring part 90AK of the helicoid member 90 is made of a piece of cotton in which the protruding part 90B is fitted into each notch part 93b, and the ring part 90AK of the helicoid member 90 has a length that is also inclined at an angle θl with respect to the direction parallel to the light #IO. The adjusting screw 94 is fitted into the hole 90b and the frame member 93KII* is fitted together, so that the frame member and the helicoid member 90 are integrated.

Therefore, in the fourth embodiment, when adjusting the movement of the focus position by zooming, the adjustment screw 94 is loosened, and the helicoid member 90 is moved back and forth along the optical axis direction together with the focus frame 38 and the #11 lens frame 35. Then, the helicoid member 90 moves back and forth while rotating with respect to the frame member 96 as the protrusion portion 90B slides within the cutout portion 95b. For example, @Luns frame 35
When the lens frame 43 is extended forward, the second lens frame 43 moves at the angle θ'
When the lens frame 35 is slightly rotated in the clockwise direction VC according to the above-mentioned inclination and retracted rearward, the second lens frame 35 is also slightly rotated in the counterclockwise direction according to the above-mentioned inclination. For this reason, the first
When adjusting the focus position of the lens frame 35, the 70-ring transmission arm 55 moves back and forth in the direction along the inclination angle θ of the 7-oak groove 95a.
does not apply any driving force to the guide bin 59, so %
The position of the 70-ting frame 58 does not change. In addition, in the fourth embodiment, as described in the first embodiment, after adjusting the movement of the focus position due to zooming, that is, after making the shift of the focus position constant regardless of zooming. V4 adjustment is performed by moving the entire lens frame in the optical axis direction with respect to the fixed/frame by means of an adjustment means (not shown) to correct the deviation of the focus position which has become constant.

In each of the above embodiments, a zoom lens barrel has been described; however, the present invention can also be applied to a normal lens barrel whose focal length does not change, and which employs a 70-ting system. Next, such a lens barrel will be explained.

The twelfth factor shows a sectional view of a lens barrel showing the fifth embodiment of the present invention, and FIG. 15 is a developed plan view showing the relationship between the respective lens frames. This lens barrel 101 holds a lens group 104, and a focus frame 108 and a fixing screw 1.
A helicoid member 110 is attached to the lens frame 105 integrated by the lens frame 105 by screwing a helicoid screw 110a into the helicoid screw 105a. The helicoid member 110 has a protrusion 110B on the inside of the ring portion 110, similar to the helicoid member 40 in the first embodiment (see FIG. 1). A stopper bin 111 installed on the outer periphery of the helicoid member 110 is located within the notch 108a of the focus frame 108, and a long hole 111 is formed in the helicoid member 110 in the optical axis direction.
An adjustment screw 114 is fitted into b, and the screw 114 is screwed into the fixed frame 102. A notch 102b is formed at the front end of the fixed frame 102 to restrict the rotational direction of the protrusion 110B of the helicoid member 110 and to fit in the notch 102b so as to be movable in the optical axis direction. Therefore, by loosening the adjusting screw 114, the position of the helicoid member 1100 in the optical axis direction with respect to the fixed frame 102 can be adjusted. A set screw 11 is attached to the rear end surface of the lens frame 105.
The front end of the 7p-ting transmission section #115 is fixed by t5. A floating cam hole 115a is formed at the rear of the 70-ring transmission member 115, and a floating lens 117 is formed in the cam hole 115a.
A guide bin 119 is fitted onto a 70-teating frame 118 holding a guide bin 119. This guide bin 119 has a long hole ID2 formed on the fixed frame 102 along the optical axis direction.
It is also penetrated by a. Note that an aperture ring 109 is fitted to the ridge on the outer periphery of the fixed frame 102, and an inner frame 120 is fixed to the rear end surface of the fixed frame 102 with a set screw 121.
The mounting member 1 is attached to the middle frame 120 by a set screw 122.
23 is fixed. Elongated hole 10 on the fixed frame 102
The length dimension of 2a is at least the helicoid screw 110a.
, 105a of the helicoid member 110 relative to the fixed frame 102! The length is longer than the sum of the adjustment movement J1 (the length of the elongated hole 110b).

In the lens barrel 101 configured as described above, the state shown in FIG.
When rotated in one direction counterclockwise H1, the helicoid member 110
Since the rotation of the lens frame 105 is restricted by the fixed frame 102, the lens frame 105 is rotated and extended forward by the pitch of the helicoid screws 105a and 110a. Then, the transmission member 115 for 70-ting is moved integrally with the lens frame 105, so the guide bin 119, which was located at the infinity position of the 70-ring cam hole 115a, is moved to the cam hole 1.
Since the floating frame 118 moves along the elongated hole 102a Vc according to the shape of the lens frame 15, the floating frame 118 moves in a direction approaching the lens frame 105, that is, in a forward direction, and close-range correction is performed.

When adjusting the focus position shift during assembly work, the adjustment screw 114 is first loosened to make the helicoid member 110 movable in the optical axis direction relative to the fixed frame 102.

When the lens frame 105 is moved in the optical axis direction, the helicoid member 110 and the unloading transmission member 115 are also moved in the optical axis direction together with the lens frame 105. cam hole 115
The guide bin 119 fitted with aVc also moves along the elongated hole 102aK on the fixed frame 102 in the optical axis direction together with the transmission member 115. That is, the lens frame 105 does not rotate when adjusting the focus position shift, and the position of the guide bin 119 above the cam hole 115a does not change.

Therefore, the relative positional relationship between the 70-ring frame 118 and the lens frame 105 does not change, and there is no possibility that the 70-ring system will be distorted during this focus position adjustment. For the above N trimming, tighten the adjustment screw 114,
The helicoid member 110 is fixed to the fixed frame 102, and the assembly work is completed.

(Effects) As described above, according to the present invention, the helicoid member is fixed to the immovable frame member so as to be adjustable in a direction having an optical axis direction component at least during focusing. There is no need to rotate the focus frame when adjusting the focus position during assembly.
In a lens barrel that uses a 70-ting system that converts the rotational component of the focus lens into a movement in the optical axis direction and performs floating, the position of the 7-keying lens shifts and the close-range correction amount becomes incorrect, resulting in problems such as 5. This has the effect of making it possible to adjust the focus position with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of the main parts of a lens barrel according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the upper half of the lens barrel according to a first embodiment of the present invention. , FIG. 6 is a perspective view of the near-field aberration correction mechanism in the lens barrel shown in FIG. 2 above, and FIG. 4 is for explaining the relationship between each lens frame of the lens barrel shown in FIG. 2 above. Developed plan view of Figure 5 (A), (
B) and (C) are main part sectional views for explaining the movement of the focus position due to zooming in the lens barrel shown in FIG. 2 above, and FIG. FIG. 7 is an exploded perspective view of the helicoid member and frame member in the lens barrel shown in the sixth factor. 8 is a cross-sectional view of a main part of a lens barrel showing a third embodiment of the present invention, FIG. 9 is an exploded perspective view of the helicoid member and frame member in the lens barrel shown in FIG. 8, and FIG. 11 is a plan view showing the relationship between the 70-ting transmission arm and the 7-ting cam hole in the lens barrel of the fourth embodiment of the present invention. FIG. 11 is the lens mirror shown in FIG. 10 above. FIG. 12 is an exploded perspective view of the helicoid member and frame member in the barrel; FIG. 12 is a sectional view of the upper half of the lens barrel showing the fifth embodiment of the present invention; FIG. 13 is J: FIG. FIG. 14 is a developed plan view for explaining the relationship between the respective frames of the lens barrel shown in FIG. 14, and FIG. 14 is a sectional view of the upper half of the lens barrel showing an example of a conventional lens barrel.

Claims (1)

[Claims] By rotating a focus frame connected to a helicoid member with a helicoid screw, a focus lens is moved back and forth in the optical axis direction to perform focusing, and a rotational component of the focus frame is transmitted via a transmission mechanism. In a lens barrel in which the floating lens is moved by converting it into a movement in the optical axis direction, the position does not change at least during focusing, and the relative position in a direction having an optical axis direction component with respect to the helicoid member is adjusted. a frame member that is later fixed integrally with the helicoid member by a fixing means; and a frame member that is interposed in the transmission mechanism, and that the floating lens is interlocked with the rotation of the focus frame during focusing, and the floating lens is connected to the helicoid member. A lens barrel comprising: a cam mechanism such that the floating lens does not move in response to movement of the focus frame due to relative position adjustment between the member and the frame member.