JPH0679100B2 - Lens moving device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens moving device effective for use in a video camera or the like.

Configuration of Conventional Example and Problems Thereof A conventional zooming mechanism for a lens barrel generally uses a cam barrel mounted on a fixed barrel to move a lens. This will be described with reference to FIG. FIG. 1 is a partial cross-sectional view of a main part showing a conventional example of a zoom lens barrel, in which 1 is a fixed barrel, 2 is a focus ring, a helicoid screw 1a provided on the fixed barrel 1, and a focus ring 2 The provided helicoid screw 2a is screwed and rotated around the optical axis to extend the focusing lenses L1, L2, L3 in the optical axis direction. The second lenses L4, L5, L6 are inserted into the first lens holding frame 8, and the screw portion 9a of the retainer 9 of the second lens L4 is screwed into the screw portion 8a of the first lens holding frame 8. Is fixed to the first lens holding frame 8. Third lens L7
Is loaded into the second lens holding frame 10 and fixed by pressing the retaining ring 11 of the third lens L7. The first and second lens holding frames 8 and 10 are fitted into guide poles 6 and 7 whose base ends are supported by the fixed barrel 1. Numeral 5 is provided with a first cam groove 14 and a second cam groove 15 for moving the first lens holding frame 8 and the second lens holding frame 10 in the optical axis direction on the peripheral surface in a direction intersecting the optical axis direction. It is a cam tube and a guide ball
The positions of the balls 6 and 7 are regulated with respect to the fixed barrel 1 by a ball support plate 17 which supports the tips of the fixed barrel 1. In the first cam groove 14 and the second cam groove 15, the second lenses L4, L5,
The cam followers 12 and 13 of the first lens holding frame 8 and the second lens holding frame 10 are engaged with each other to regulate the positions of the L6 and the third lens L7 on the optical axis. Also, the cam barrel 5
A pin 16 is planted in the inner surface of the fixed barrel 1. The pin 16 penetrates a long groove 18 formed in the fixed barrel 1 in the circumferential direction orthogonal to the optical axis direction and projects outward from the fixed barrel 1. Reference numeral 19 denotes a zoom ring, in which a zoom gear 20 is rotatably fitted around an optical axis, and a pin 16 is engaged with a long groove 21 formed on the inner peripheral side in the optical axis direction. That is, the zoom ring is operated by the operation knob 22.
When 19 is rotated, the pin 16 engaged with the long groove 21 is driven and the cam barrel 5 is rotated, so that the second lens L4 in the first lens holding frame 8 and the second lens holding frame 10 L5, L6 and third
The position of the lens L7 is regulated by the first cam groove 14 and the second cam groove 15, and zooming is performed.

However, in the above construction, the assembly is carried out by supporting the first and second lens holding frames 8 and 9 on the fixed barrel 1 through the guide poles 6 and 7 and then inserting the cam barrel 5 and supporting the balls. The plate 17 holds the cam barrel 5. Then, the first and second lens holding frames 8 and 9 are moved to predetermined positions, and the cam followers 12 and 13 are moved to the first and second positions through through holes (not shown) appropriately provided in the fixed barrel 1. There is a problem that a procedure of attaching to the lens holding frames 8 and 9 is required, and skill is required for assembling.

An object of the present invention is to provide a small-sized lens moving device that simplifies the configuration by introducing a flat plate cam mechanism for lens movement and opening at least one end of the cam groove, and simplifying the configuration. It is intended.

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 are movable in the optical axis direction, and the first and second lens holding frames. A guide shaft that guides the first lens follower, a first cam follower provided on the first lens holding frame, a second cam follower provided on the second lens holding frame, and the first and second
First and second movable elements that are engaged with the cam follower and are arranged in a direction intersecting the optical axis on a plane parallel to the optical axis, at least one end side is open, and are movable in a direction substantially orthogonal to the optical axis. Of the flat cam member having a groove cam, and a substrate having a guide member for holding the guide shaft and for guiding the flat cam member, the assembly is facilitated, A compact and inexpensive lens moving device can be obtained.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

2 is a perspective view of an essential part of a lens moving device according to an embodiment of the present invention, FIG. 3 is a plan view of the essential part, and FIG. 4 is A of FIG.
-A is a sectional view. The lens substrate 31 is a member for mounting the first lens group A, the second lens group B, the third lens group C, the fixed lens D, the master lens group E, and the diaphragm 32, and the first lens holding frame 33 is The first lens group A is held, the second lens holding frame 34 holds the second lens group B, and the third lens holding frame 35 holds the third lens group C. The second lens holding frame 34 is inserted into a guide pole 36 supported by the lens substrate 31 through a hole 34a, and is engaged with a guide pole 37 supported by the lens substrate 31 via a rotation preventing cutout portion (not shown). When combined, the lens substrate 31 is supported so as to be movable in the optical axis direction 50.
Similarly, the third lens holding frame 35 also has a hole 35a in the guide pole 37.
And is supported so as to be movable in the optical axis direction 50 on the lens substrate 31 by engaging with the guide pole 36 via the rotation preventing notch 35b. A cam plate 38 is a first groove cam 39 for moving the second lens holding frame 34 in the optical axis direction 50 and a second groove cam 39 for moving the third lens holding frame 35 in the optical axis direction 50. 40 is formed in a direction intersecting the optical axis direction. Further, an opening portion 39a is formed at one end of the first groove cam 39, and an opening portion 40a is formed at one end of the second groove cam 40. The cam plate 38 is a guide member formed on the lens substrate 31. Optical axis direction 50 by 31a, 31b, 31c
It is movably supported in the direction of arrow 49 orthogonal to.
A first cam follower 41 provided on the second lens holding frame 34 engages with the first groove cam 39, and a second cam follower provided on the third lens holding frame 35 engages with the second groove cam 40. 42 is engaged. Further, a concave portion 43 shown by a broken line in FIG. 3 is formed on the back surface of the cam plate 38. Further, as shown in FIGS. 3 and 4, a projection 31d is formed on the lens substrate 31, and a flexible stop member 44 is fixed by a fastening member 45. The stop member 44 will be located in the recess 43 of the cam plate 38 after assembly.

The zoom motor 46 is supported by the lens substrate 31, and a motor pinion 47 press-fitted into its motor shaft (not shown) meshes with a rack 48 formed on the cam plate 38.

The operation of the lens moving device of the present embodiment configured as described above will be described below. 5 and 6 are plan views of relevant parts for explaining the operation. In FIG. 5, the second lens holding frame 34 and the third lens holding frame 35 are provided on the lens substrate 31 by a guide pole (not shown) in the optical axis direction 50.
The procedure for mounting the cam plate 38 is as follows. First, the cam follower 41 provided on the second lens holding frame 34 and the cam follower 42 provided on the third lens holding frame 35 are connected to the open portion 39a of the first grooved cam 39 of the cam plate 38 and the second grooved cam 40. It is moved to a position that engages with each opening 40a. Next, the cam plate 38 is attached to the guide members 31a, 31b, 31c.
Insert it in the direction of arrow 49 along with. At this time, the projection 31d formed on the lens substrate 31 and the stop member 44 are attached to the cam plate 3
It goes into the recess 43 of 8. Further, the flexible stop member 44 is pressed in the counterclockwise direction by the wall 43a of the recess 43 to bend, but the cam plate 3 reaches the position of FIG. 6 where the wall 43a disappears.
When 8 is inserted, the stop member 44 returns to the position where it is not pressed. In this state, the cam plate 38 stops the stop member 44 shown in FIG.
From the position where the front end portion 44a of the lens and the wall 43b formed in the concave portion 43 of the cam plate 38 contact each other, the projection 31d of the lens substrate 31 shown in FIG.
And the wall 43c formed in the recess 43 of the cam plate 38 comes into contact with the wall 43c so as to be movable. Next, the zoom motor 46 supporting the motor pinion 47 is attached to the lens substrate 31, and the motor pinion 47 and the rack 48 formed on the cam plate 38 are meshed with each other. This allows the zoom motor
The rotation output of 46 is transmitted to the cam plate 38, and the cam plate 38
The cam follower 41 of the second lens holding frame 34 engaged with the first groove cam 39 and the cam follower 42 of the third lens holding frame 35 engaged with the second groove cam 40 move toward the optical axis. Direction 50
Will be driven to.

As described above, according to the present embodiment, the lens moving device that facilitates the assembling can be realized by forming the opening portion on at least one end of the groove cam. Also, by using a flat cam, it is possible to easily form a high-precision cam, and it is possible to reduce the weight as compared with a conventional lens barrel that uses a cam barrel mounted on a fixed barrel. In addition, a compact and inexpensive lens moving device can be realized.

In the above embodiments, the cam plate in which the groove is formed is described, but any structure may be used as long as it has a function of guiding the cam follower. For example, as shown in FIG. 7, the cam follower is guided to the plate. The walls 39 'and 40' may be formed. Further, in the above embodiments, the stop member is provided on the lens substrate, but the stop member may be provided on the cam plate.

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, it is possible to extremely easily perform the conventional assembly, and to realize a small-sized and inexpensive lens moving device having a simplified configuration. The effect of being able to be obtained is obtained. In addition, since it is easy to mold by using a flat cam, it is rich in mass production,
In addition, it is possible to reduce the weight as compared with the conventional one in which the lens is moved by using the cam barrel mounted on the fixed barrel.

[Brief description of drawings]

FIG. 1 is a partially cutaway side sectional view showing a conventional zoom lens barrel, FIG. 2 is a perspective view of a main portion of a zoom lens barrel according to an embodiment of the present invention, and FIG. Figure 4 is the third
FIG. 5 is a cross-sectional view taken along the line AA of FIG. 5, FIG. 5 and FIG. 6 are plan views of relevant parts for explaining the operation, and FIG. 7 is a perspective view showing a cam plate in another embodiment of the present invention. 31 …… Lens substrate, 31a, 31b, 31c …… Guide member, 33, 3
4,35 …… First to third lens holding frame, 36,37 …… Guide pole, 38 …… Cam plate, 39,40 …… First and second groove cams, 39a, 40a …… Groove cam Opening part, 41, 42 …… Cam follower, 44 …… Stopping member, 46 …… Zoom motor, 47 …… Motor pinion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Kajino 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-53-32726 (JP, A) JP-A-53-44021 (JP, A) Actual development Sho 58-141206 (JP, U)

Claims (1)

[Claims] 1. A first and second lens moving frame movable along the optical axis, a guide shaft for guiding the first and second lens moving frames, and a first lens moving frame provided on the first lens moving frame. First
Of the cam follower, the second cam follower provided on the second lens moving frame, the first and second cam followers, and intersecting the optical axis on a plane parallel to the optical axis. The first and second grooved cams, which are arranged in the same direction, at least one end side of which is released and whose one end side merges, and which are movable in a direction substantially orthogonal to the optical axis, and regulate the movement range. Flat cam member provided with a concave portion on the back surface, regulating means for engaging the concave portion of the planar cam member to regulate the movement range, and a guide member for holding the guide shaft and guiding the flat cam member. And a substrate on which the lens is formed.