JPH04184404A - Zoom lens barrel - Google Patents

Abstract

PURPOSE:To accomplish focusing driving for a focusing lens group whose moving amount by zooming is large by providing a focusing communicating barrel which mediates and transmits the focusing driving force of a focusing driving member to a focusing lens. CONSTITUTION:The focusing communicating barrel 8 which mediates and transmits the focusing driving force of the focusing driving member to the focusing lens is provided. This figure shows the state of the wide end of a focusing cam 13g and the telephoto end of a focusing cam 13g' provided in the small diameter part 13b of a cam barrel 13 and a detail around the focusing communicating barrel 8 which is concerned in the state, and an arrow A show progress that the barrel 8 shifts to a focusing close state from a focusing infinity state. Then, an arrow B shows progress that the barrel 8 moves to the telephoto end from the wind end of previous zooming, and is equal to a fixed pin cam 13c provided in the large diameter part 13a of the cam barrel 13. Thus, the focusing driving of the focusing lens whose moving amount by zooming is large is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an inner focus zoom lens, and is particularly effective when a lens with a large zoom stroke is used as a focus lens.

"Prior Art" In recent years, as zoom lenses have become more compact, have higher magnification, and have become more autofocus, an inner focus method in which lenses other than the first group on the object side are moved has become common. As a focus driving method, as shown in Japanese Patent Application No. 1-284594 proposed by the present applicant, a focus pin provided on a focus lens is driven by a key protruding from a focus drive section.

"Problem to be Solved by the Invention" However, in the above proposal, if the amount of zooming movement of the focus lens group is large, it may be difficult to connect the focus spin and the focus key. I tried to make the smaller groups into focus groups.

"Means for Solving the Problem" According to the present invention, the first lens group and the focus lens behind the optical axis of the first group lens move by zooming, and in response to this, the focus lens is held, rotated and A cam cylinder that moves in the axial direction, a focus drive section,
In the zoom lens barrel having a focus drive member protruding from the focus drive unit, the zoom lens barrel is provided with a focus communication tube that transmits the focus drive force of the focus drive member via an intermediary to the focus lens to be focus driven. This makes it possible to focus drive a focus lens that requires a large amount of movement during zooming.

"Embodiment" Figures 1 to 1O show one embodiment of the present invention.
The figure is a sectional view showing the telephoto end state of the lens. FIG. 2 is a sectional view showing the wide end of the lens. FIG. 3 is a developed view of the cam cylinder. FIG. 4 is a developed view of the fixed cylinder. FIG. 5 is a developed view of the fitting portion of the fifth group lens barrel. FIG. 6 is a developed view of the first group lens barrel. FIG. 7 is a developed view of the hood cam cylinder.

FIG. 8 is a developed view of the focus communication cylinder. FIG. 9 is a zoom movement diagram during zooming of each zoom group. FIG. 1O is a detailed view around the focus.

In FIGS. 1 to 9, ■ represents the 1st group lens, ■ represents the 2nd group lens, ■ represents the 3rd group lens, ■ represents the 4th group lens, ■ represents the 5th group lens, and ■ represents the 6th group lens. (The part indicated by A in Figure 1 is a removable filter.) In the figure, 1 is a fixed cylinder, 1a is an outer straight groove, 1b is an inner straight groove, and IC is a 2nd group holding hole. There are three equal parts in each area. Further, the outer diameter portion 1h has a hole 11 for use. 2
A mount is fixed to the fixed tube 1 with screws 2a, holds the bottom cover 3, and has a detachable stopper pin 2b. The fixed cylinder 1 has an outer peripheral part 1e, a distance window part 4 in the large diameter part 1e, and a step part if and a fitting part 1g in the inner surface of the outer peripheral part 1e. 1f and the fitting portion 1g, the rotary cylinder 5 is rotatably held. At the tip of the rotary cylinder 5, a pin 5a is connected to the opposing pin 2.
It is screwed in from the outer periphery at two points, and has three protrusions 5b toward the inner periphery at the rear end. 6 is a focus unit, and a unit main body 6a is fixed to the fixed barrel 1 with screws 6b.

Further, 6c is a known ultrasonic motor. 6d is an output member. Reference numeral 6e designates roller members which are rotatably held at three equal locations on the outer periphery of the roller ring 6g with shaft screws 6f. The inner diameter of the roller ring 6g is fitted into the unit main body 6a and is rotatably held, and a distance scale 61 is provided on the outer periphery. Reference numeral 6h denotes an intermediate member which is fitted and held in the unit main body 6a and has three fitting vertical grooves 6j on its outer periphery. It fits into the protrusion 5b on the periphery and can rotate two times integrally with the rotary cylinder 5. Further, 6 is a pressure member of the ultrasonic motor 6C, and the unit main body 6
In a, the ultrasonic motor 6c, the output member 6d, and the roller member 6e.

The intermediate members 6h are sequentially and simultaneously pressurized. 7 is a focus key, which is connected to the focus unit 6 by a screw 7a.
It is fixed to the 6g roller ring inside. Further, the key 7 has a fitting vertical groove portion 7b (not shown).

Reference numeral 8 denotes a focus communication cylinder, which is fitted into the inner surface of the fixed cylinder 1. It also has a vertical groove 8b on its inner circumferential surface. pin 8a
is screwed into the outer peripheral surface of the focus communication tube 8,
Thrust is regulated by a hole 11 in the small diameter portion 1h of the fixed cylinder 1, and rotation is regulated by a fitting longitudinal groove 7b (hereinafter referred to as the key) of the key 7 (not shown).

Reference numeral 9 denotes a first group lens barrel that holds the first group lens I, and also holds the fixed barrel 1 at a fitting portion 9a on the inner surface of the rear end.
At the same time, a straight key 9b is fixed to the inner surface of the rear end with a screw 9c.

Then, the straight key 9b is inserted into the straight groove 1 on the outer surface of the fixed cylinder 1.
By fitting with a, it is held in the fixed cylinder 1 so as to be freely movable in a straight line. Further, the first group lens barrel 9 has three cam grooves 9d equally divided in its front half. In addition, the hood cam barrel 10 is fitted and held in the outer circumferential fitting portion, and thrust regulation of the hood cam barrel 10 is also realized, so that the hood cam barrel 10 is not connected to the first group lens barrel 9. It is held in place so that it can rotate freely.

Reference numerals 9e denote dowels provided at the front outer periphery of the first group lens barrel 9, and are provided at three equal locations. Reference numeral 9f denotes a collar extending toward the outer periphery of the first group lens barrel 9, and has a fitting portion 9g on the outer periphery. The cam cylinder 10 for the hood is provided with three straight grooves lOa and three cam grooves 10a at equal intervals.

Reference numeral 11 denotes an operation ring, which has a fitting portion 11a at the middle portion of the inner surface, and the fitting portion 11a is a fitting portion 9g provided on a collar portion 9f extending toward the outer circumferential side of the first group lens barrel 9. By fitting with and controlling the thrust, the operation ring 11 is connected to the first group lens barrel 9.
However, it is possible to simultaneously control the movement forward and backward. Further, the inner surface of the operating ring 11 is provided with two opposing inner longitudinal grooves 11b, and the inner longitudinal grooves 11b are provided with pins 5a screwed into the tip of the rotary cylinder 5 at two opposing locations from the outer periphery. Due to the fitting, it is possible to always stably transmit the rotational operation of the operation ring 11 to the rotary cylinder 5 and the intermediate member 6h in the focus unit 6.

12 is a filter frame, and the filter A is attached to the inner circumference of the tip.
A filter screw 12a is cut for screwing in the filter, and a fitting portion 12b is provided on the inner peripheral portion of the rear end, and dowels 12c are provided at three equal locations on the inside of the fitting portion 12b. Furthermore, vertical grooves 12d are provided at three equal locations on the inner surface of the intermediate portion. The vertical groove 12d fits into a dowel 9e provided on the front outer periphery of the first group lens barrel 9, thereby restricting rotation. Furthermore,
At the same time that the fitting part 12b on the inner periphery of the rear end of the filter frame 12 is fitted with the outer periphery of the hood cam cylinder lO, a 3.
Since the dowels 12c provided at equal intervals engage with the cam grooves 10a provided in the hood cam cylinder 1o,
Eventually, when the hood cam cylinder 10 rotates, the filter frame 1
2 moves the first group lens (2) held in the first group lens barrel 9 in a straight line.

13 is a cam cylinder having a substantially large diameter portion 13a and a small diameter portion 13b;
The large diameter portion 13a is fitted and held on the inner diameter of the fixed cylinder 1. Further, as shown in FIG. 3, the large diameter portion 13a has
Fixed pin cam 13013 group cam 13d, 4 group cam 13e
, three fifth group cams 13f are provided at equal intervals. Further, the small diameter portion 13b is provided with a focus cam 13g. Further, there is a fitting part 13h with a diameter one step larger on the outer peripheral part of the front end, and a fitting pin 1 is provided on the outer surface of the fitting part 13h.
3i are screwed into three equally spaced places.

The fitting pin 13i passes through the cam groove 9d of the first lens barrel 9 and simultaneously engages with the linear groove 10a of the hood cam barrel 10. Therefore, the amount of rotation of the cam cylinder 13 regulates the amount of rotation of the hood cam cylinder 10, and the amount of extension of the filter frame 12 is determined as explained above.

Reference numeral 14 denotes a second group lens barrel, which holds the second group lens and has a fitting portion 14a on its outer periphery, and fixing pins 14b are provided at three equal locations on the fitting portion 14a. Note that the fixing pin 14b provided on the fitting portion 14a engages with the fixing pin cam 13c provided on the large diameter portion 13a of the cam barrel 13, and at the same time engages with the second group holding hole 1c provided in the fixing barrel 1. engaged. Therefore, the second group lens barrel 14 is fixed to the fixed barrel 1. Further, the cam barrel 13 has two positional elements in the shape of a fixed pin cam 13c provided on the large diameter portion 13a and a cam groove 9d provided in the front half of the first group lens barrel 9, so that the rotational position and the thrust position are determined. As a result, the cam cylinder 13 performs a rotating movement by moving the operating ring 11 back and forth. 13j is a movable diaphragm fixed to the front end surface of the cam cylinder 13.

Reference numeral 15 denotes a fifth group lens barrel that holds the fifth group lens, has a fitting portion 15a, and is fitted and held in the large diameter portion 13a of the cam barrel 13. Further, as shown in FIG. 5, a fifth group pin 15b is screwed into the fitting portion 15a of the fifth group lens barrel 15, and three third group grooves 150 and three fourteenth group grooves 15d are equally provided. ing. The fifth group pin 15b screwed into the fitting portion 15a of the fifth group lens barrel 15 is connected to the cam barrel 13.
Since the fifth group cam 13f provided on the large-diameter portion 13a of the cam 13f engages with the linear groove 1b on the inner surface of the fixed barrel 1 at the same time, the predetermined zoom movement can be made in a straight line by the rotational movement of the cam barrel 13. I can do it.

16 is a known electromagnetic aperture unit.

Reference numeral 17 denotes a third group lens barrel, which holds a third group lens (2) and an electromagnetic diaphragm unit 16.

Further, the third group lens barrel 17 is fitted and held in the fifth group lens barrel 15, and a third group pin 17a screwed into the fitting surface is provided on the fitting portion 15a of the fifth group lens barrel 15. Group groove 15c and
Since they are simultaneously engaged with the third group cam 13d provided on the large diameter portion of the cam barrel 13, a predetermined zoom movement can be performed in a straight line by the rotational movement of the cam barrel 13.

Reference numeral 18 denotes a 4th group lens barrel, which holds the 4th group lens (2). Further, the fourth group pin 18a, which is fitted and held in the fifth group lens barrel 15 and screwed into the fitting surface, is attached to the fitting portion 15 of the fifth group lens barrel 15.
Since it is simultaneously engaged with the fourth group groove 15d provided in a and the fourth group cam 13e provided in the large diameter part of the cam cylinder 13,
As with the third group lens barrel 17, a predetermined zoom movement can be performed in a straight line by rotating the cam barrel 13.

Reference numeral 19 denotes a 6th group lens barrel that holds the 6th group lens (2), is fitted and held on the inner surface of the small diameter portion 13b of the cam barrel 13, and is screwed into the fitting portion of the 6th group lens barrel 19. pin 19a
is positioned by engaging with the focus cam 13g of the cam cylinder 6 and the vertical groove 8b on the inner peripheral surface of the focus communication cylinder 8.

In Figure 9, the zoom parameter is set to P= at the wide end.
0, and P=1 at the telephoto end.

The 1st nI is a nearly linear movement, but if the zoom movement amount Z, (P) of the 1st group I is expressed as a function of P, Z, (P) = -8
7,7291xP ~5.9751xP2 -1-38.227xP3 -18.8765xP'-7,2885XP'+6.64197xP' (Formula 1).

The second group is a fixed group.

The third group pays out nonlinearly.

The fourth group also moves out nonlinearly.

The fifth group also moves out nonlinearly.

The sixth group also moves out nonlinearly. Furthermore, in this example,
Since the 6th group (■) is also used for focus operation, the zoom movement amount in the infinite shooting state can be expressed as a function Za (P) of P, similar to the zoom movement amount Z+ (P) of the 1st group I mentioned above. , Z, (P)=-52,2729xP +23.3911xP2 +39.3588xP"-236,458xP'+530.4948xP'-580,5656xP'+292.4738xP'-56,326298xP'... When the amount of movement of the 6th group (■) when focusing is expressed as DX (P) when considering the above-mentioned 26 (P) as the reference position for each shooting object, the amount of movement at each distance from infinity is as follows. It is expressed as follows.

DX,;,=O...(Formula 3) %Formula%...(Formula 4) DX7. ,'=0.0988010890+0.342
63702xP 10, 706005850xP2 +0.857507810xP' +0. 486142130xP' +3. 78180260xP'-6,76691370xP' +9. 04521350xP'-3,90948150xP"...(Formula 5) %Formula%...(Formula 6) DXjP,"=0. 196421380+0,6
82520480xP 11.38218740xP2 +1. 40201600xP3 +3. 18587210xP' 10, 552946600xP'-3,22240080xP' +10. 4507290xP'-5,61543700xP'...(Formula 7) %Formula%...(Formula 8) %Formula%,,''= 0.358994040+1.2
5004060xP +2. 46682720xP" +1. 77421100xP' +11. 5002260xP' = 16, 9023260 ) Dx ::;= 0. 901905270 3.06
121860xP 16.06886870xP2 +7. 03123610xP'13.33171080xP' +25. 0760880xP'-38,7647970xP'150.1789960xP'-20,9403790xP' (Formula 11) % Formula % (Formula 12) FIG. This is a detailed view of the wide end of the focus cam 13g and the tele end of the focus cam 13g', and the surroundings of the focus connecting tube 8 related thereto. 8 shows the progress of transition. Further, arrow B indicates the transition from the wide-angle end to the telephoto end of the zoom, and arrow B is equal to the fixed pin cam 13c provided on the large diameter portion 13a of the cam barrel 13.

*The length 26 in the figure is the amount of zooming movement of the 6 groups in an infinite state.

In the figure, θ is the rotation angle of the focus from infinity.

In the figure, FX (wide, θ) is the amount of focus movement at the wide end in F(θ).

In the figure, FX(tele, θ) is the amount of focus movement at the telephoto end in F(θ).

As is clear from the figure, the closer the zoom is to the telephoto end, the larger the focus movement amount FX becomes.

*Note that point A in the figure is the origin when representing the cam shape.

"Description of Focus Cam Shape" In FIG. 1O, point A corresponds to the infinite focus position at the wide end, and is set as the origin. Consider a parameter P that is positive in the right direction in the figure from point A, and P
=1 is the abscissa of the infinite position of the telephoto end. Also, when the ordinate of the cam is DF (P), which gives a positive value in the direction in which the light passes from the origin A (downward direction in the figure).

DF(P)=0.16483574xP+0.234
11311xP2 +1.0812920xP3 -3.0355993xP'+6.0473302xP'-4,0403452xP'+1.3991619xP' (Formula 13).

"Explanation of zoom operation" Next, in the above configuration, when the operation ring 11 is pulled out from the wide end to the tele end for zooming operation, the first group lens barrel 9 moves straight by the same amount as described above, and at the same time The cam cylinder 13 performs rotational feeding. For this reason, the filter frame is extended in a straight line relative to the first group lens barrel 9. Further, the rotation of the cam ring 9 causes the fifth group lens barrel 15 to move in a straight line,
At the same time, the third group lens barrel 17 and the fourth group lens barrel 18 also move straight forward at the same time.

On the other hand, when the focus is fixed as described above, the sixth group lens barrel moves in a straight line because its rotation is restricted by the vertical groove 8b of the focus communication tube 8 which is connected to the focus key.

"Description of Focus Operation" The focus rotation angle θ has a positive value in this embodiment.

(This is called a wide start cam.) The amount of extension at the focus rotation angle θ at the zoom amount P is as follows: The cam coordinate DF (P 〇) at (P + θ) is (
What is necessary is to find out how much the cam coordinates have changed from the cam coordinates DF (P) at P).

Therefore, if the amount of feeding is set as DF (P, θ), then DF
It is expressed as (P, θ)=DF (P+θ)−DF (P). Here, for example, P=1, that is, at the telephoto end, the amount of extension DX (1
) If xm and DF (1,0) become the same, it means that the focus is at the telephoto end, and without changing θ (in other words, fixing the focus), zoom from P=O to P=
When changing to 1, the cam deviation amount ΔDX (P)xm is: ΔDX (P) = DF (P, θ) - DX (1)xm
... is expressed by (Equation 15), and ΔDX (P) is always 0 (between P-0 and P=1)
The cam 13g expressed by the above-mentioned (Equation 13) is determined so that it is close to .

"Effects of the Invention" As explained above, the first lens group and the focus lens group behind the first lens on the optical axis move due to zooming, and in response, the focus lens group is held and rotated in the optical axis direction. In a zoom lens barrel having a cam barrel that moves, a focus drive section, and a focus drive member protruding from the focus drive section, the focus drive force of the focus drive member is applied to the focus lens to be focus driven. By providing a focus communication tube for mediating transmission, it is possible to drive the focus of a focus lens group that requires a large amount of movement during zooming, and there is an effect that a high-magnification zoom lens barrel can be designed compactly.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a zoom lens barrel as an example in a telephoto end state. FIG. 2 is a sectional view of the zoom lens barrel of FIG. 1 in a wide end state. FIG. 3 is a developed view of the cam cylinder of FIG. 1. FIG. 4 is a developed view of the fixed cylinder of FIG. 1. FIG. 5 is a developed view of the fitting portion of the fifth group lens barrel shown in FIG. FIG. 6 is a developed view of the first group lens barrel shown in FIG. FIG. 7 is a developed view of the hood cam cylinder of FIG. 1. FIG. 8 is a developed view of the focus communication tube of FIG. 1. FIG. 9 is a zoom movement diagram of each zoom group in this embodiment. FIG. 10 is a detailed diagram of the focus area of this embodiment. l...Fixed barrel 5...Rotating barrel 6...Focus unit 6a...Unit body 6C...Ultrasonic motor 6d...Motor output member 6h...Intermediate member 7...Key 8 ...Focus connecting tube 8a...Pin 8b...Vertical groove 9...1st group lens barrel lO...Cam tube for hood 11...Operation knob 13...Cam tube 13d...3 Group cam 13e...Fourth group cam 13f...Fifth group cam 13g...Focus cam 14...Second group barrel 15...Fifth group barrel 17...Third group barrel 18... 4th group lens barrel 19... 6th group lens barrel point A... Cam origin arrow A... Close focus rotation direction θ... Focus rotation angle FX... Focus extension amount Z6... Focus group Zoom movement amount procedural amendment (Mutsu) March 15, 1991 Director General of the Patent Office Satoshi Uematsu Patent Application No. 316239 of 1990 2 Name of the invention Zoom lens barrel 3 Relationship with the person making the amendment case Patent applicant address 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (100
) Canon Co., Ltd. Representative: Keizo Yamaji 4, Agent address: Canon Co., Ltd., 3-30-2 Shimomaruko, Ota-ku, Tokyo 146 (telephone: 3758-2111) 5, Specification subject to amendment and drawings 6. Contents of amendment (1) Delete "2" on page 5, line 14 of the specification. (2) Correct Figure 10 of the drawings as shown in the attached sheet.

Claims (1)

[Claims] (1) A first group lens group and a focus lens behind the first group lens on the optical axis move due to zooming, and a cam cylinder that holds the focus lens and rotates and moves in the optical axis direction in response to the movement; In a zoom lens barrel having a focus drive unit and a focus drive member protruding from the focus drive unit, a focus transmits the focus drive force of the focus drive member via an intermediary to the focus lens to be focus driven. A zoom lens barrel characterized by being equipped with a connecting tube.