JPS5823603B2 - zoom lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zoom lens, and more particularly, the present invention relates to a zoom lens, and more particularly, the present invention includes a single operating ring, and performs zooming by sliding operation of the operating ring along the optical axis of the lens system. Focusing is performed by rotating the lens system around the optical axis.
This invention relates to an improvement of a zoom lens.

Various so-called linear operation type zoom lenses of this type have already been proposed and implemented as products.

In these zoom lenses, the movable barrel for focusing is connected to the fixed barrel via a helicoid mechanism, and the movable barrel for zooming is connected to the fixed barrel through a helicoid mechanism. The operating ring is fitted into the fixed barrel in such a way that the rotation of the lens system is blocked by the fixed barrel and only sliding movement along the optical axis of the lens system is possible. For the movable barrel, a coupling means capable of transmitting only the rotation about the optical axis of the lens system to the movable focusing barrel, for example, a coupling mechanism consisting of a pin and a linear keyway, is used. On the other hand, the movable barrel for zooming is connected to the movable barrel for zooming via a coupling means capable of transmitting only the sliding movement along the optical axis of the lens system to the movable barrel for zooming. When the operation ring slides along the optical axis of the lens system, the movable barrel for focusing is not driven in any way due to the interposition of the coupling mechanism consisting of the pin and the linear keyway, and only the movable barrel for zooming is moved. The lens system of the operating ring is slid along the optical axis together with the operating ring, thereby displacing the zooming lens group on the optical axis to perform zooming.On the other hand, the lens system of the operating ring rotates around the optical axis. During the movement, the movable barrel for zooming is not driven in any way through the intervention of the above-mentioned connecting means, and only the movable barrel for focusing is rotationally driven via the above-mentioned pin and keyway.
At that time, it is extremely common to have a configuration in which the lens group for focusing is moved along the optical axis by the helicoid mechanism described above, and thereby the focusing lens group is displaced on the optical axis to achieve focusing. It is true.

By the way, when a coupling mechanism consisting of a pin and a keyway is adopted as a means for coupling the operation ring and the movable focusing barrel, it is necessary to adjust the fit between the pin and the keyway. This arises as a very troublesome problem.

In other words, it is desirable that the fit between the pin and the keyway be gentle in order to make the operation of the operation ring easier and to improve the operability of the operation ring during zooming and focusing. However, if this is too loose, the fit between the pin and keyway will increase, making it easy for the pin and keyway to be damaged due to shocks when operating the operating ring, etc. Additionally, the operation ring may move due to a slight impact, causing inconveniences such as the carefully adjusted zoom magnification or the focus plane being changed inadvertently during photographing.

Furthermore, if the movable cylinder and the pin are made of metal, for example, the sliding play between the pin and the keyway will be directly transmitted to the operating ring when the operating ring is operated. This also brings about the inconvenience of giving the user a very unpleasant feeling.

One way to solve this problem is, for example, by fitting a roller made of rubber or synthetic resin onto the pin, and then inserting the pin into the keyway through this roller. A configuration in which they fit together is conceivable, but in such a configuration, the friction against the key groove increases due to the roller, which in particular causes new inconveniences such as the following: arise.

In other words, when the focusing movable cylinder is rotationally driven by the rotating operation of the operating ring, it is moved along the optical axis by a part of the torsion of the helicoid mechanism. If the pin and keyway that connect the movable cylinder and the operation ring are relatively tight, and therefore there is a lot of friction between them, the focusing will be difficult. As the movable barrel for zooming moves, the operating ring is dragged by it and moves as a unit, and as a result, the movable barrel for zooming slides, causing fluctuations in the adjusted zoom magnification. This causes inconveniences such as the following.

The present invention has been made in view of the above-mentioned circumstances, and in particular, as mentioned above, the connection of the operating ring to the movable barrel for focusing is relatively strong, and therefore, the focusing As the movable barrel for zooming moves back and forth, the operating ring is moved in the direction along the optical axis following the movable barrel, and as a result, the movable barrel for zooming is slid and completely The purpose is to prevent the occurrence of situations such as zooming being performed unexpectedly or the zoom magnification that has been carefully adjusted being changed every time focusing is performed. In order to achieve the desired purpose, when focusing, the movable barrel for zooming and the operating ring are moved in the direction along the optical axis of the operating ring relative to the movable barrel for zooming. to,
Its feature is that it is connected by a connecting means that allows movement following the focusing movable cylinder.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, to explain the structure of one embodiment, in FIGS. 1 and 2, 1 is a lens mount tube (not shown here) fixed to the camera body, and a relay is mounted on the inner periphery of the lens mount tube. - Lens holding frames 2.3 holding lenses R1 and R2 are fixedly attached to their threaded parts 2a and 3a, respectively, and an aperture adjustment ring 4 is rotatably mounted on the outer periphery of the lens holding frames 2.3. It is fitted.

Reference numeral 5 denotes an intermediate cylinder that holds the aperture device, and is fixed to the mount cylinder 1 with screws 6, and a fixed ring 8 that holds the aperture blades 7 and a rotating ring 9 are fitted to the inner circumference of the intermediate cylinder. equipped.

The rotating ring 9 has an aperture drive pin 10 on a part of its outer circumference.
The pin 10 is inserted into the circumferential groove hole 5a formed in the intermediate tube 5 and extends to the outside, and the tip thereof is connected to the aperture adjustment ring 4. The aperture drive lever 11 is engaged.

Therefore, when the aperture adjustment ring 4 is rotated with respect to the mount tube 1, the rotation ring 9 is rotated, and the photographing aperture diameter defined by the aperture blades 7 is adjusted.

Reference numeral 12 denotes a fixed cylinder fixed to the intermediate cylinder 5 by screws 13, and has a helicoid threaded portion 12a formed on the outer periphery of its front end, and a linear guide groove 12b formed in its center. Furthermore, an auxiliary cylinder 14 is attached to a screw 15 at the rear end.
It is installed depending on the

Note that 12c is a stepped portion for defining a focusing area.

Reference numeral 16 denotes a movable focusing barrel which is rotatably fitted into the helicoidal threaded portion 12a of the fixed barrel 12 by its helicoidal threaded portion 16a, and a focusing lens F is held on the inner periphery thereof. The lens holding frame 17 is fixed by its threaded portion 17a, and a linear keyway 16b is formed in the center thereof.

In addition, 18 is a stopper pin implanted in the movable cylinder 16, and a stopper pin 18 provided in the fixed cylinder 12 is a stopper pin.
c to define the focusing area.

Reference numeral 19 denotes a seat plate fixed to the front end surface of the fixed cylinder 12 with screws 20, and the seat plate 20 and a part 12d of the fixed cylinder 12
Guide rods 21 and 22 are respectively fixed parallel to the optical axis O of the lens system, and a lens holder holding a variator lens V is attached to the rods 21 and 22. A frame 23 and a lens holding frame 24 holding the compensator lens C are fitted so as to be slidable along the optical axis 0, respectively.

25 is a zooming cam ring rotatably fitted on the inner periphery of the fixed cylinder 12, and includes cam grooves 25a and 25b for controlling the movement of the variator lens (2) and the compensator lens C; Furthermore, it has a cam groove 25c for its own rotational drive, and the cam grooves 25a and 2
Pins 26 and 27, which are implanted in the lens holding frames 23 and 24, are fitted into the holes 5b, respectively.

Reference numeral 28 denotes a movable barrel for zooming that is loosely fitted around the outer periphery of the fixed barrel 12 and the auxiliary barrel 14, and near the rear end is a helicoid threaded portion formed in the fixed barrel 12 and the movable barrel 16 for focusing. A circumference Q28a having an inclination angle corresponding to the torsion angle α of parts 12a and 16a is formed (shown in the second figure), and a pin 29 is implanted in the front end of the circumference Q28a. The cam ring 25 is inserted through the linear guide groove 12b formed in the fixed cylinder 12.
It fits into a cam groove 25c formed in the cam ring which is being rotated.

Therefore, the movable barrel 28 for zooming is connected to the fixed barrel 12.
On the other hand, only sliding in the direction along the optical axis 0 is allowed, and during the sliding, the cam ring 25 is rotationally driven via the cam groove 25c.

30 is provided on the outer periphery of the movable barrels 16 and 28 for focusing and zooming so as to be able to both slide along the optical axis O of the lens system and rotate about the optical axis O. A roller 32 made of a rubber material or a synthetic resin material is fitted into a linear keyway 16b formed in the movable barrel 16 for the movable barrel 16 for focusing. via the pin 31 fitted with the zooming cylinder 28,
They are connected to each other via a pin 33 that fits into a circumferential groove 28a formed in the movable cylinder 28.

In the above configuration, when the operating ring 30 is first slid along the optical axis O of the lens system, the pin 31 and roller 32 of the focusing movable barrel 16 slide in the linear keyway 16b. Only the movable barrel 28 for zooming is slid integrally with the operating ring 30 along the optical axis 0 by the pin 33 without being driven in any way to move the movable barrel 28 for zooming. Pin 2 installed in 28
9 rotates the cam ring 25 through the cam groove 25c, and the cam grooves 25a and 2 formed in the cam ring 25 rotate.
5b, the variator lens holding frame 23 and the compensator lens holding frame 24 are moved in a predetermined relationship along the optical axis 0 while being guided by the guide rods 21 and 22, respectively, to perform zooming. It is done.

On the other hand, when the operation ring 30 is rotated about the optical axis 0 of the lens system, the movable focusing cylinder 16 is rotationally driven via the pin 31 and the keyway 16b, and at this time, the helicoid threaded portion 16a and the focusing cylinder 16 are rotated. The fixed barrel 12 is moved along the optical axis O by a screw lead in the helicoid threaded portion 12a, and thereby the focusing lens F is displaced along the optical axis O to perform focusing.

By the way, during this focusing, the pin 31
is relatively tightly fitted into the key groove 16b by the roller 32, the operating ring 30 is moved for focusing by the friction of the fitting between the roller 32 and the key groove 16b. It is dragged by the cylinder 16 and is also moved in the direction along the optical axis 10 following the movable cylinder 16, but at this time, the circumference of the movable cylinder 28 for zooming, in which the pin 33 is fitted, is moved. Since the groove 28a is formed with an inclination angle corresponding to the screw lead angle α of the helicoid threaded portions 12a and 16a in the fixed barrel 12 and the movable focusing barrel 16, the angle of inclination of the circumferential groove 28a movement in the optical axis 0 direction with respect to the zooming movable cylinder 28 is allowed, and as a result, the optical axis 0 direction of the operation ring 30 is
Despite the movement in the direction along the zoom lens, the zooming cylinder 28 is not driven, so that a situation in which the adjusted zoom magnification is changed during focusing is prevented. It will become like that.

In the embodiment described above, the operating ring 30 and the movable barrel 28 for zooming are connected using a connecting means consisting of the pin 33 and the circumferential groove 28a.
For example, it is of course possible to replace it with a threaded connection using screws, and even in this case, a very simple method can be used to
During focusing, the operation ring can be allowed to move along the optical axis relative to the zooming movement barrel.

That is, in FIG. 3, 28' indicates a movable barrel for zooming, and a part of its outer periphery is provided with a groove formed in the fixed barrel 12 and the movable barrel 16 for focusing, in place of the circumferential groove 28a in the above embodiment. A male screw 28'-a is formed having a helix angle corresponding to the torsion angle α of the helicoid screw portions 12a and 16a.

Further, 30' indicates an operation ring, and a part of its inner circumference is provided with the movable cylinder 28' instead of the pin 33 in the above embodiment.
A female thread 30'a is formed to be screwed into the male thread 28'a of the operating ring 30' and the movable cylinder 28' are screwed together by these threads 30'a and 28'a. There is.

Therefore, when the operating ring 30' is slid along the optical axis 0,
A movable barrel 28' for zooming, which is threadedly connected to this, is slid integrally along the optical axis O, so that zooming is performed in the same manner as described above, and the operation ring 30' is When rotated about axis 0, the focusing movable cylinder 16 is moved along the optical axis O by the helicoid mechanism to perform focusing, and at this time, the operating ring 30' and the zooming movement According to the leads of screws 30'a and 28'a in the cylinder 28', the operating ring 30'
The optical axis 0 follows the moving cylinder 16 for focusing.
Movement in the direction along the zooming cylinder 28' is allowed, and therefore the same operation and effect as in the previous embodiment can be obtained.

To further explain the structure of the zoom lens described above, in the embodiment of the present invention, the arrangement of the cam ring and the movable barrel for zooming with respect to the fixed barrel is as follows: The structure is such that the cam ring is rotatably fitted on the inner periphery of the fixed cylinder, and the movable cylinder for zooming is slidably fitted on the outer periphery of the fixed cylinder. This is particularly advantageous in improving the operability of the operating ring during zooming.

That is, during zooming, the movable barrel for zooming is slid along the optical axis of the lens system, while the cam ring is rotated around the optical axis of the lens system by the stationary movement of the movable barrel. However, if a moving tube for zooming is directly fitted on the outer periphery of this cam ring with a string, a very complex frictional force will be exerted on the circumferential area between the two due to their different movements. As a result, there is a fear that the operability of the operating ring will be extremely deteriorated.In contrast, according to the above-mentioned configuration shown in the embodiment of the present invention,
Since a fixed barrel is interposed between the movable barrel for zooming and the cam ring, complex frictional forces based on mutually different movements act between the movable barrel and the cam ring during zooming. There is no possibility that they will fit together, and therefore, there is an effect of maintaining good operability of the operating ring.

As detailed above, the present invention provides a conventional so-called linearly operated zoom lens that moves along the optical axis of the lens system integrally with the operation ring only during zooming.
During focusing, a movable barrel for zooming, which is prevented from rotating about the optical axis with respect to the fixed barrel, and the operation ring are connected to each other, so that the optical axis of the lens system of the operation ring is moved relative to the movable barrel for zooming. According to this, the operation ring can be connected to the movable focusing barrel. It is relatively strong, and therefore, during focusing, as the movable barrel for focusing moves back and forth, the operation ring is moved in the direction along the optical axis following the movable barrel, and as a result, zooming Situations may occur where the movable barrel for the camera is slid and zooming is performed completely unexpectedly, or the zoom magnification that has been carefully adjusted is changed each time focusing is performed. This has the effect of preventing this from occurring.

In the detailed explanation of the present invention, an example has been described in which the pin 31 is fitted into the keyway 16b by the roller 32 in the connecting means between the operation ring 30 and the moving cylinder 16 for focusing. Keyway 16b
The present invention is also useful for zoom lenses where the coupling means is configured to fit into the lens.

That is, even when the pin 31 is directly fitted into the key groove 16b without using the roller 32, the pin 31 is moved into the movable barrel 16 by the focusing operation by rotating the operating ring 30 around the optical axis.
The movable cylinder 16 engages with the side wall of the straight groove 16b, and the movable cylinder 16 is moved in the optical axis direction by the helicoid coupling of the helicoids 16a and 12a, and the acting force that moves the focusing movable cylinder 16 in the optical axis direction is Operation ring 3 via pin 31
0, a force that moves the operating ring 30 in the optical axis direction also acts on the operating ring 30.

Therefore, especially if the fitting relationship between the operation ring 30 and the zooming movable barrel 28 is relatively loose, the zooming movable barrel 28 will be easily moved by the focusing operation, and the present invention is useful in such a case.

BRIEF DESCRIPTION OF THE DRAWINGS) FIG. 1 is a sectional view showing details of the configuration of an embodiment of the zoom lens according to the present invention, and FIG.
FIG. 3 is a partially cutaway perspective view showing the configuration of the lens, especially the main parts related to the present invention, which is a modified example of the embodiment shown in FIGS. 1 and 2, especially FIG. 1. and FIG. 2 is a partially cutaway perspective view showing only the configuration of essential parts that are different from that shown in FIG. 2.

12... Fixed barrel, 16... Moving barrel for focusing, 12a and 16a... Components of helicoid mechanism, 25... Cam ring for zooming. , 28゜28'...Moving barrel for zooming, 30, 30'...Operation ring, 16b, 31 and 32...Operation ring and moving barrels for focusing. 28a and 33, 28'
a and 30'a... Components of means for connecting the operating ring and the movable tube for zooming, 25c and 29...
...Constituent element of the means for connecting the movable barrel for zooming and the cam ring, F...Focusing lens, ■...Variator lens, C...
Compensator lens, R...11 Ray lens, 0...Lens system optical axis.

Claims (1)

[Scope of Claims] 1. An operating ring capable of focusing and zooming operations, and a movable focusing barrel that is helicoidally coupled to a fixed barrel and engaged with the operating ring in a locking relationship consisting of a linear groove and a key member. and a zoomin connected to the operating ring by a connecting means that moves together in the optical axis direction and rotates relative to the optical axis. In the zoom lens having a movable barrel for zooming, the coupling means includes an engagement pin implanted in one of the operating ring or the movable barrel for zooming, and an engagement pin formed in the other of the operating ring or the movable barrel for zooming, which engages with the engagement pin. 1. A zoom lens comprising circumferential grooves that meet each other, the circumferential groove having a lead angle corresponding to a lead of a helicoid joint between the movable focusing barrel and the fixed barrel. 2. The zoom lens according to claim 1, wherein the connecting means is a screw mechanism having a lead corresponding to the lead in the helicoidal connection.