JP2543297Y2 - Zoom lens device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a zoom lens device used as a lens assembly or the like in a television camera device.

[Related Art] A lens assembly having a zoom mechanism is used in a television camera device. This lens assembly is usually
The lens system includes four lens groups including a focus lens group, a variator lens group, a compensator lens group, and a relay lens group in this order from the subject side. Here, the zooming operation is performed by the variator lens and the compensator lens. Displacing both lens groups in a direction to separate them from each other results in a low magnification (wide) and a displacement in a direction close to each other. In general, a high magnification (telephoto) is used.

In order to move the movable lens composed of the variator lens and the compensator lens described above in the optical axis direction, a plurality of support pins are provided on a lens frame that supports these movable lenses, and a direction parallel to the optical axis is provided on the lens barrel. A guide groove is provided in each of the guide pins, and each of the support pins is engaged with the guide groove so as to be displaceable in the optical axis direction. The movable lenses are connected to a zoom cam mechanism in order to perform a zoom operation. As this zoom cam mechanism, a pair of groove cams is formed on the outer peripheral surface of a cylindrically formed cam cylinder, and drive pins are protruded from the lens frame of each movable lens, and each of the drive pins is respectively fitted to the groove cam. The movable lens is moved by rotating the cam barrel.

The zoom operation described above includes a system using a servo mechanism including a motor and the like and a manual operation system.

As a zooming method by manual operation, for example, a zoom operating means is provided, and a photographer pushes and pulls the zoom operating means by hand, thereby moving the movable lenses close to and away from each other, in a wide direction and a tele direction. There is known a configuration in which a zoom operation is performed. In addition, it is necessary to regulate each position of the wide end and the telephoto end in the zoom operation. For this purpose, a rotation restricting member is provided on the cam cylinder, and the rotation restricting member restricts the rotation range of the cam cylinder. ing.

[Problem to be Solved by the Invention] By the way, when operating the zoom operation means to displace the movable lens for zooming, if the operation is performed at a low speed, there is no particular problem. When displaced from the stroke end to the other stroke end position at a high speed as described below, when the cam cylinder comes into contact with the stopper and the lens stops, the lens is in contact with the drive pin due to the inertial force acting on the lens. It can be swung around the connection with the cam cylinder. Here, when the movable lens for zoom is heavy, such as a lens assembly in a television camera device, a large inertia force acts and shakes greatly, which may damage the drive pin and the groove cam. There is a disadvantage that there is. In addition, when the lens is shaken, a phenomenon in which an image displayed on the monitor is momentarily shaken or blurred, and it is difficult to see the image.

In recent years, particularly in recent years, there has been a strong demand for downsizing and downsizing of the lens assembly, and in order to meet such demands, the length of the entire lens assembly in the optical axis direction must be reduced. However, when the variator lens is displaced at a high speed in the wide direction with the focus lens set at infinity (inf), the variator lens collides with the focus lens and damages the lens surface. As a result, there is a problem that the size and size of the lens assembly cannot be reduced.

The present invention has been made in view of the above points, and its purpose is to displace a movable lens and a cam when a movable lens constituting a zoom lens is displaced by manual operation of a cam mechanism. It is an object of the present invention to provide a zoom lens device in which there is no possibility of damaging a connecting portion or colliding lenses.

Means for Solving the Problems In order to achieve the above-mentioned object, a rod-shaped cam member arranged outside the lens barrel and having a rotation axis parallel to the optical axis is provided. By providing a drive pin that engages with the lens barrel and a support pin that engages with a guide groove that is provided in the lens barrel and that is long in the optical axis direction on the lens frame of the movable lens for zooming, and by operating the cam member, The movable lens is displaced in the optical axis direction, and when the movable member is displaced at least in the wide direction by the cam member, the movable member is at a stroke end position of the cam member or a position immediately after the stroke end. A stopper is provided on the fixed-side member, the stopper being in contact with at least a portion of the movable lens that is substantially opposite in the circumferential direction to the drive pin. You.

[Operation] With this configuration, when the movable lens forming the zoom lens is displaced and the zoom operation is performed at a high speed to the stroke end position, the lens frame of the movable lens is centered on the drive pin due to its inertia force. However, since a stopper is provided at a stroke end position of the movable lens or at a position immediately after the movable lens, for example, a fixed cylinder formed of a lens barrel or the like, Will surely stop. Accordingly, since an excessive inertia force does not act on the connecting portion between the driving pin and the cam portion, there is no possibility that this portion is damaged. Moreover, since the stopping accuracy of the movable lens is improved, the stopper is provided at the stroke end position in the wide direction of the variator lens constituting the movable lens, so that the variator lens does not collide with the focus lens. By reducing the interval between them, the entire zoom lens can be made smaller and more compact.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows the overall appearance of the zoom lens device, and FIG. 2 shows its cross section.

In FIG. 1, reference numeral 1 denotes a lens barrel. Inside the lens barrel 1, focus lenses 10,
A variator lens 11, a compensator lens 12, and a relay lens 13 are provided, and a diaphragm 14 is interposed between the compensator lens 12 and the relay lens 13. Here, the variator lens 11 and the compensator lens 12 constitute a movable lens for zoom which is movable in the optical axis direction.

These variator lens 11 and compensator lens
In order to make the lens 12 displaceable, as shown in FIG. 3, three support pins 15 and 16 are provided at positions shifted by 120 ° on the lens frames 11a and 12a of the lenses 11 and 12, respectively. The bearings 15a, 16a are connected to the tips of the support pins 15, 16, respectively. The bearings 15a, 16a of the support pins 15, 16 are provided on the peripheral body of the lens barrel 1.
Are provided at three places, and each of the guide grooves 2 is elongated in the optical axis direction. in this way,
The lenses 11 and 12 are supported by the lens barrel 1 at three points, and the bearings 15a and 16a roll along the guide grooves 2 so that the lenses 11 and 12 can move in the optical axis direction. ing.

Thus, when the lenses 11 and 12 are displaced in a direction approaching each other, the lens becomes higher in magnification (tele side), and conversely, when the lenses 11 and 12 are separated from each other, the lens becomes lower in magnification (wide). Side). As described above, the zoom cam mechanism 20 is provided to displace the lenses 11 and 12 to the tele side and the wide side.

The zoom cam mechanism 20 includes a cam cylinder 21 which is disposed outside the lens barrel 1 and forms a rod-shaped cam member arranged so that the rotation axis is parallel to the optical axis. Groove cams 22a and 22b are formed. This groove cam 22
Drive pins protruding from lens frames 11a and 12a respectively on a and 22b
Bearings 17a, 18a provided at the tips of the 17, 17 are engaged. In order to enable the drive pins 17 and 18 to be engaged with the groove cams 22a and 22b, a slit 3 parallel to the guide groove 2 is formed in the peripheral barrel of the lens barrel 1. Therefore, when the cam cylinder 21 is rotated, the bearings 17a, 18a provided at the tips of the drive pins 17, 18 roll along the groove cams 22a, 22b, and the variator lens 11 and the compensator lens 12 come close to each other. -The zoom operation is performed by being displaced in the separating direction. Further, in order to regulate the displacement stroke ends of the variator lens 11 and the compensator lens 12 in the wide direction and the tele direction, the cam cylinder 21 is provided with a rotation regulating member (not shown) for regulating the rotation range thereof. .

The cam cylinder 21 is rotatably mounted on a support shaft 23. In order to rotate the cam cylinder 21, a pulley 24 is
Are integrally connected. An operation wire 25 is wound around the pulley 24, and the operation wire 25 is connected to a reciprocating block 28 via pulleys 26a, 26b, 27a, 27b. The reciprocating block 28 is attached to a slide ring 30 fitted to a sheath member 29a of a flexible cable 29. This slide ring 30 is connected to an operation rod 29b through a slit 31 provided in a sheath member 29a,
By pushing and pulling the operation stick 29b, a zoom operation can be performed. The push / pull operation of the operation rod 29b is performed by a manual operation of a person who performs photographing. For this purpose, a finger hook 32 is provided at the tip of the operation rod 29b.

Further, reference numeral 40 denotes a stopper 40 attached to the inner surface 1a of the lens barrel 1 as a fixed-side member that does not move during zoom operation.
As shown in FIG. 4, the stopper 40 has a regulating portion 40b formed of an inwardly projecting wall connected to one end of a mounting portion 40a formed on the lens barrel 1 and having an annular shape. I have. When the cam barrel 21 rotates and the compensator lens 11 and the compensator lens 12 are displaced in the wide direction, the stoppers 40 move the lens frames 11a and 12a at the same time as the end of the displacement stroke or with a slight delay. A position where the lens frames 11a and 12a can abut on the stroke end position or a position immediately after the stroke end when the variator lens 11 and the compensator lens 12 are displaced in the wide direction. It is arranged in.

This embodiment is configured as described above. To perform a zoom operation on the lens assembly, the photographer manually pushes and pulls the operation rod 29b. As a result, the reciprocating block 28 moves in the direction of the arrow in FIG. 1 and the wire 25 is pulled, so that the pulley 24 around which the wire 25 is wound rotates, and the cam cylinder 21 rotates together therewith. Here, the cam cylinder 21 is provided with groove cams 22a and 22b, and each of the groove cams 22a and 22b has a drive pin 17 and a compensator lens 1 protruding from the lens frame 11a of the variator lens 11, respectively.
Since the drive pin 18 protruding from the second lens frame 12a is engaged, the lenses 11, 12 are displaced in the direction of approaching / separating. Here, when the lenses 11 and 12 are separated from each other, a low magnification state is set, and when the lenses 11 and 12 are displaced in a direction approaching each other, a high magnification state is set.

Thus, in the lens assembly of the television camera device, since the variator lens 11 and the compensator lens 12 are relatively heavy, when these lenses 11 and 12 are displaced by performing a zoom operation, the Lens 1
Inertial force works on 1,12. In particular, when the operation is performed rapidly in the wide direction, the lenses 11, 12 are displaced at high speed. And when it reaches the stroke end position in the wide direction,
The cam cylinder 21 engages with the regulating member and its rotation is stopped. However, between the cam cylinder 21 and the lenses 11 and 12, drive pins 17 and 18 are provided.
Since these drive pins 17 and 18 only contact the groove ends of the groove cams 22a and 22b of the cam cylinder 21 and are not particularly restricted in the direction returning from the stroke ends, the lenses 11, 12 are It does not stop with high accuracy, and is swung in the direction indicated by the arrow in FIG. 2 around the drive pins 17 and 18 by the inertial force.

However, since the stoppers 40 are provided at the positions of the displacement stroke ends of the lenses 11 and 12 in the wide direction, the lens frames 11a and 12a are moved simultaneously with or immediately after the rotation of the cam cylinder 21 is stopped. The stoppers 40 absorb the inertial forces of the lenses 11 and 12 so that the lenses 11 and 12 are stopped smoothly. Therefore, since the inertial force does not directly act on the engaging portion between the drive pins 17, 18 and the groove cams 22a, 22b, there is no possibility that these may be damaged. In addition, when the stop accuracy of the lenses 11 and 12 is improved in this way, even if the focus lens 10 is at infinity, that is, in a state of inflation, it is located at a position very close to the stroke end position in the wide direction of the variator lens 11. Since there is no possibility that the two lenses 10 and 11 come into contact with each other, the distance between them can be shortened, and the entire lens assembly can be made compact.

In the above-described embodiment, the stopper is provided at the stroke end position in the wide direction of the lens. However, a similar stopper can be provided at the stroke end position in the tele direction as necessary. . Although the stopper is formed in the shape of an annular ring, this configuration is most preferable because the stopper can be in contact with the entire surface of the lens and the inertia force can be absorbed more smoothly and efficiently. However, for example, the lens may be divided into a plurality of portions in the circumferential direction, and the lens may be prevented from touching even if a stopper is provided only at a position opposite to the projecting portion of the drive pin. Further, in addition to the stopper described above, the stopper may be constituted by a means such as protruding a pin on the inner surface of the lens barrel, or providing a step on the inner surface of the lens barrel. Furthermore,
Although shown as a lens assembly in a television camera device, a similar stopper may be provided in a lens assembly for ordinary photography, and the configuration of the zoom cam mechanism is limited to that shown. Not to mention that it is not.

[Effects of the Invention] As described above, in the present invention, when the movable lens is displaced at least in the wide direction by the zoom cam, the lens frame of the movable lens is applied at the stroke end position or a position immediately after the stroke end. Since the movable stopper is provided, even if the movable lens is rapidly displaced to the displacement stroke end position, the stop accuracy of the movable lens is extremely good, and the inertial force can be effectively absorbed. There is no danger of excessive force acting on the connection between the drive pin and the zoom cam to damage that part.In addition, the stopper is provided in this way, but the movable lens is restricted by the stopper until it reaches the stroke end position. And it can be reliably displaced to the stroke end position in the wide direction. Further, since the movable lens can be prevented from swaying at the stroke end position, the distance between the movable lens and another lens can be reduced, and the effect of reducing the size and size of the entire lens assembly can be achieved. Play.

[Brief description of the drawings]

1 shows an embodiment of the present invention, FIG. 1 is an external view of a lens assembly, FIG. 2 is a cross-sectional view of a main part of the lens assembly, and FIG. 3 is an end view taken along the line III-III of FIG. , Fourth
The figure is an external view of the stopper. 1: lens barrel, 2: guide groove, 3: slit, 10: focus lens, 11: variator lens, 12: compensator lens, 11a, 12a: lens frame, 13: relay lens, 14: aperture,
15, 16: support pins, 17, 18: drive pins, 20: zoom cam mechanism, 21: cam cylinder, 22a, 22b: groove cam, 40: stopper, 40a: mounting portion, 40b: regulating portion.

Claims (1)

(57) [Scope of request for utility model registration] A driving pin for engaging a groove cam of the cam member, the driving pin being provided on the lens barrel; And a support pin that engages with a guide groove that is long in the optical axis direction is provided on the lens frame of the movable lens for zooming, and the movable lens is displaced in the optical axis direction by operating the cam member. In the above, when the movable lens is displaced at least in the wide direction by the cam member, at least at the stroke end position of the cam member or at a position immediately after the stroke end, at least a circumferential direction of the lens with respect to the drive pin is provided. A zoom lens device, wherein a stopper that abuts on a substantially opposite side is provided on a fixed side member.