JPS59104613A - Lens moving device - Google Patents

Abstract

PURPOSE:To realize a small-sized and inexpensive video camera with a simple constitution by constituting so that each holding frame is moved in the optical axis direction by a rotation of a plane cam plate for driving two lens holding frames. CONSTITUTION:When an output of a zoom motor is transferred to a gear provided on the end face of a plane cam plate 23 from a driving gear 33, the plane cam plate 23 rotates in the direction as indicated with an arrow 43 centering around a shaft 40. As a result, the first lens holding frame 27 and the second holding frame 28 are controlled by cam grooves 25 and 26, respectively, and execute a zooming operation. Accordingly, a small-sized and inexpensive video cameras can be realized by a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lens moving device that is effective for use in video cameras and the like.

Conventional Structure and Problems The conventional zooming mechanism for a lens barrel generally uses a cam barrel attached to a fixed barrel to move the lens. This will be explained with reference to FIG. FIG. 1 is a partial sectional view of the main parts of a conventional example of a zoom lens barrel. 1 is a rigid 5t barrel, 2 is a focus link, and a focus ring 2 is attached to a helicoid screw 1a provided on a fixed barrel 1. The focusing lens Ll is screwed together with the helicoid screw 2ad5 provided therein and rotated about the optical axis.
.

L2. L3 is light/I! Maneuver in the 111 direction. Second lens L4. L5. L6 is inserted into the first lens holding frame 8, and the threaded part 9a of the presser foot 9 of the second lens L4 is screwed into the threaded part 8a of the first lens holding frame 8. It is fixed at 8.

The third lens L7 is inserted into the second lens holding frame 10, and is fixed by being pressed by the presser ring 11 of the third lens L7. 5 is a first cam a14 for moving the first lens holding frame 8 and the second lens holding frame 10 in the optical axis direction.
This is a cam cylinder provided with a second cam 1R15, and its position is regulated by a pole support plate 17. first cam a1
4 and the second cam groove 15, a second lens L4,
L5.

In order to regulate the positions of L6 and third lens L7 on the optical axis, first lens holding frame 8 and second lens holding frame 1 are used.
0 pins 12 and 13 are engaged, and a pin 16 is implanted in the cam cylinder 5.

18 is a zoom ring, in which a zoom gear 21 is rotatably rotated around the optical axis, and the inner circumference 11. Ill
The pin 16 is held in a long groove 19 formed in the groove.

That is, when the zoom ring 18 is rotated, the pin 16 engaged with the long groove 19 is driven and the cam cylinder 5 is rotated.
The second lenses L4 and L5 in the first lens holding frame 8 and the second lens holding frame 10.

Zooming is performed by regulating the positions of L6 and third lens L7 by the first cam groove 14 and second cam groove 15.

However, 1. In the configuration in which the lens is moved using a cam attached to a fixed barrel as described above, it is necessary to cover the lens movement frame with at least a triple barrel consisting of a cam barrel, a fixed barrel, and an operation ring. There is.

Furthermore, in the cam cylinder and fixed cylinder, extremely high positional accuracy is required for each movable lens group, so high-precision machining for positioning each movable lens group is essential.

For this reason, there is a certain limit to the reduction in the number of parts, and there are disadvantages in that the processing noise associated with high-precision processing is also expensive. 1. The cam cylinder formed by the cam groove obtained by penetrating the inside of the cylinder is deformed by the cam in process,
It is impossible to eliminate distortion. In order to reduce the deformation of the cam cylinder, the rotation angle of the cam groove cannot be made large.

Since the cam groove's rotational power is small, the cam curve becomes tight, which tends to cause uneven operation.Also, since the cam advance relative to the rotation angle: 1k is large, even a small error has a large effect. Was.

OBJECTS OF THE INVENTION An object of the present invention is to provide a lens moving device that simplifies the configuration by introducing an \11-plane cam mechanism to move the lens, thereby making it possible to realize a compact and inexpensive video camera.

Structure of the Invention In order to achieve the above object, the lens moving device of the present invention includes a first lens holding frame and a second lens holding frame that can move in the direction of the light beam Qh force.
a lens holding frame, a first cam for driving the first lens holding frame, and a second cam for driving the second lens holding frame, and the cams are aligned with the optical axis. By rotating within parallel planes, 1) the first lens holding frame and the second holding frame are moved in the optical axis direction;

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows a perspective view of essential parts of a lens barrel in an embodiment of the present invention. In FIG. 2, reference numerals 22 refer to a lens group A, a second lens group B, a third lens [C, a fixed lens moving frame 34, and a master V lens group (not shown)] for performing focusing operations, zooming operations, and fixed positions, respectively. Attachment to the lens substrate is also done with gold. 37 is a second lens holding frame, 27 is a second lens holding frame, and 28 is a third lens holding frame. The second lens holding frame 27 has a guide pole 36 supported by the lens substrate 22 with a hole 27aK.
Guide pole 3 inserted through and supported by lens board 22
7 is fully engaged with a rotation prevention notch (not shown), thereby being supported on the lens substrate 22 so as to be movable in the optical axis direction.

Similarly, the guide pole 37 of the third lens holding block 28 is connected to the hole 2.
8a, and is supported so as to be movable in the optical axis direction on the lens substrate 22 by engaging with the guide pole 36.

23 is a first lens unit for moving the second lens group B in the optical axis direction.
511 is a cam plate provided with a cam groove 25 and a second cam groove 26 for moving the third lens group C in the optical axis direction,
It is rotatably attached to a shaft (not shown) implanted in the lens substrate 22. 29 is a zoom motor, which is attached to a plate 30;
The output of 9 is transmitted from the motor tooth p431 press-fitted into the motor shaft 29a to the drive gear 33 via the idler gear 32 and the crown gear (not shown), and further transmitted to the gear 24 formed on the end surface of the planar cam plate 23. will be done. As a result, the planar cam plate 23 is rotated, and the second lens holding frame and the third lens holding frame are moved in the optical axis direction.

The operation of the lens moving device of this embodiment configured as described above will be described below.

Fig. 3 is a plan view showing the relationship between the planar cam plate, the second lens holding frame, and the third lens holding frame in the wide-angle state, and Fig. 4 is a plan view showing the relationship between the planar cam plate, the second lens holding frame, and the third lens holding frame in the telephoto state.
There are 11 drawings showing the relationship between the lens holding frames. In the second lens holding frame 27, a guide pole 36 supported by the lens substrate is pushed through the hole 27a, and a rotation prevention notch (not shown) is secured to the guide pole 37 supported by the lens substrate 22. By doing so, it can be moved in the direction of the optical axis. Similarly, the guide pole 37 of the third lens holding frame 28 is pushed through the hole 286, and the third lens holding frame 28 is moved in the optical axis direction by engaging the guide pole 36 with a circulation prevention opening (not shown). A first cam follower 41 implanted in the second lens holding frame 27 is engaged with the first cam groove 25 of the planar cam plate 23, and the second cam follower 41 is supported by the second lens holding frame 27.
A second cam follower 42 implanted in the third lens holding frame 28 is engaged with the cam groove 26 .

In J3LJ, the output of the zoom motor is the drive figure 33
When the signal is transmitted to the gear 24 provided on the end surface of the planar cam plate, the planar cam plate 23 rotates about the shaft 40 in the direction of the arrow 43. As a result, the second lens holding frame 27 and the second lens holding frame 28 respectively
, performs a zooming operation while being regulated by the second cam groove 26, and moves at a position of +t-4 as shown in FIG.

As described above, according to this embodiment, by introducing a planar cam mechanism to the zooming mechanism of the lens theory one word, compared to the conventional system in which the lens is moved using a cam attached to a fixed j word. It is possible to greatly reduce the number of parts, and by using a flat cam, a high-precision cam can be molded using a spacer, making it possible to realize a compact and inexpensive video camera. , In the above implementation row, the first cam groove and the @2 cam groove were integrated.・As explained in terms of the drive member,
The first cam groove and the fj2 cam groove may be formed as separate members, and these may be joined by a ring.

Effects of the Invention As is clear from the above description, the present invention has the advantage that the cam t required in the conventional configuration in which the entire lens movement is performed using a cam piece attached to a fixed barrel is increased by 1° II! A large number of parts such as a fixed cylinder and an operating ring are required, and it is possible to reduce the number of parts to a large extent by using, for example, a flat cam plate. Further, when a planar cam plate is used, excellent effects such as ease of molding and ease of mass production and easy high-precision machining can be obtained. And with this,
An excellent effect can be obtained in that a compact and inexpensive video camera with a simplified configuration can be realized.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side sectional view showing a conventional zoom lens barrel, FIG. 2 is a perspective view of the main part of the lens barrel O in an embodiment of the present invention, and FIGS. 3 and 4 are the same according to the present invention. FIG. 3 is a plan view of main parts in the embodiment. 1...Fixed barrel, 2...Focus ring, 5...Cam simple, 18...Zoom operation ring, 22...Lens Board, 23...
・117-sided cam plate, 25.26...cam 7g,
27.2B...Lens movement frame, 29...
・Zoom motor, 31... Motor gear, 33.
...Drive gear, 36.37...Guide pole, 41.42...Cam follower, A...
...Focus lens group, B...Second lens group, C...Third lens group. Name of agent: Patent attorney Toshio Nakao and 1 other person
3 Figure 4 z 3

Claims (4)

[Claims] (1) A first lens holding frame and a second lens holding frame that are movable in the optical axis direction, and a first lens holding frame that rotates within a plane parallel to the optical axis for driving the first lens holding frame. and a second cam that rotates in a plane parallel to the optical axis for driving the second lens holding frame. (2) Patent No. 311 characterized in that the il cam and the second cam are configured (1'4) so that they can rotate synchronously.
” The lens moving device according to item (1) of the desired scope. (3) The lens moving device according to claim (1), wherein the first cam and the second cam are formed on the same member. (4) The lens moving device according to claim (1), wherein the first cam and the second cam are drive cams.