JPS6361211A - Lens moving device - Google Patents

Abstract

PURPOSE:To obtain a small-sized and inexpensive lens moving device by forming the first and second lens holding frames, which can be moved in the direction of the optical axis, with thin plates which are provided with auxiliary grooves for reduction of the change due to forming and providing a cylindrical driving member. CONSTITUTION:A cam cylinder 30 is made from a thin stainless steel plate, and the first cam groove 30a, the section cam groove 30b, a notched part 30c, and auxiliary grooves 31a, 31b, 31c, and 31d are formed on the plane thin stainless steel plate by a press and this stainless steel is rolled into the cam cylinder 30. It is rolled into the cam cylinder 30 having a prescribed outside diameter, and end faces 30d parallel with the optical axis are welded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a lens movement Vi'' that is effective for use in video cameras and the like.

Conventional Technique 447 As a conventional zooming mechanism for a lens barrel, a cam barrel attached to a fixed barrel is generally used to move the lens.

An example of the conventional lens moving device mentioned above will be described below with reference to the drawings.

FIG. 3 is a partial sectional view of the main parts of a conventional zoom lens barrel. Helicoid screw l provided in fixed barrel 1
The helicoid screw 2a provided on the focusing ring 2 is fitted onto a, and the focusing lens L is rotated around the optical axis.
1. L2. Extend L3 in the optical axis direction. Focusing lens LL
, L2. L3 is pressed and fixed by a lens holder 3 and a spacer 4. Variable power lens group L4. L5. L6 is inserted into the first lens holding frame 8, and the threaded part 9a of the holding ring 9 of the variable magnification lens L4 is inserted into the threaded part 8a of the first lens holding frame 8.
It is fixed to the first lens holding frame 8 by being screwed into the first lens holding frame 8. The correction lens L7 is inserted into the second lens holding frame 10 and fixed by the pressing force of the presser spring 11. The first lens holding frame 8 is supported so as to be movable in the optical axis direction by inserting a guide ball 6a into a long six part 8b and engaging a guide pole 6c in a notch part 8c. Similarly, the second lens holding frame IO is also supported movably in the optical axis direction by inserting a guide pole 6b into the long portion 10a and engaging a guide ball 6C in the notch Job. The cam frame 5 has a first cam groove 1 for driving the first lens holding frame 8 and the second lens holding frame 10 in the optical axis direction.
4 and a second cam groove 15 are provided. first cam'd4
14 and the second cam/315 are variable magnification lens groups L4 and L5, respectively. In order to regulate the positions of L6 and the correction lens L7 on the optical axis, pins 12 and 13 implanted in the first lens holding frame 8 and the second lens holding frame 10, respectively, are engaged and the cams are engaged. A pin 16 is implanted in the cylinder 5, and extends through an elongated hole 17 to the outside of the fixed cylinder l.

In the zoom ring 18 having the legitimate child 20, a zoom gear 21 is fitted so as to be rotatable around the optical axis, and a pin 16 is engaged with a long groove 19 formed on the inner circumferential side. That is,
When the zoom ring 18 is rotated, the pin 16 engaged with the long groove 19 is driven, and the cam barrel 5 is rotated, so that the variable power lens in the first lens holding frame 8 and the second lens holding frame 10 is rotated. Group L4. L5. Zooming is performed by regulating the positions of lens L6 and correction lens L7 by first cam groove 14 and second cam groove 15.

As mentioned above, the cam barrel is one of the important parts that regulates the position of each movable lens, which requires high positional accuracy, so up until now, high-precision machining has been performed using lathes, milling, and other machining methods. .

However, the above-mentioned machined cam cylinder has a disadvantage in that the machining cost associated with high-precision machining is high. Further, in a cam cylinder formed by a cam groove obtained by penetrating the inside of the cylinder, it is impossible to eliminate deformation and distortion of the cylinder due to cam groove machining. Furthermore, even if the cam cylinder is made thinner in order to reduce the size and weight, there is a certain limit due to the deformation and distortion of the cylinder caused by the above-mentioned processing.

The problem that the invention seeks to solve The present invention solves the above problems by conventional lathe processing.

A small and inexpensive lens moving device is provided by replacing the cam cylinder, which has been processed using expensive processing methods such as milling, with a thin plate member molded into a cylindrical shape.

Means for Solving the Problems In order to solve the above problems, 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 a first lens holding frame and a second lens holding frame that can be moved in the optical axis direction. A first cam for driving the lens holding frame, a second cam for driving the second lens holding frame, and an effect of reducing deformation due to molding of the first cam and the second cam. The drive member is formed into a thin plate shape with auxiliary grooves arranged at different angles, and is formed into a cylindrical shape centered on the optical axis.

According to the above-described configuration, the present invention reduces the processing cost of the cam cylinder by constructing the cam cylinder that moves the lens and positions it at a predetermined position from a thin member molded into a cylindrical shape, such as a thin stainless steel plate or resin. By reducing the width and making the cam cylinder three-thick, it is possible to downsize the other constituent members, thereby making it possible to create a compact and inexpensive lens moving device.

EXAMPLE Hereinafter, a lens moving device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a cam cylinder in one embodiment of the present invention. In FIG. 1, the cam cylinder 30 is a thin stainless steel plate, which is pressed into a flat plate to form a first cam groove 30a, a second cam groove 30b, a notch 30c, and auxiliary grooves 31a, 31b, and 31c.

31d and then rolled by roll forming. FIG. 2 shows the variations among the first cam grooves and the second cam grooves after molding in three types of cam plates with different arrangement of auxiliary grooves. As is clear from FIG. 2, it can be seen that the variations in the cam plate 3 in which the auxiliary grooves are effectively arranged are further suppressed.

The outer diameter of the cam cylinder is rounded to a required size for rotatably mounting it on the mounting section of the lens moving device. moreover,
The end face 30d parallel to the optical axis is welded at both ends as shown in FIG. This is mounted on the inner peripheral side of the fixed barrel 1 shown in FIG. 3 so as to be rotatable around the optical axis. Cam grooves 30a, 30b
The pin 12 of the first lens holding frame 8 and the pin 13 of the second lens holding frame 10 are engaged with each other.

A pin (not shown) implanted in the zoom ring 18 having the eldest child 20 passes through an elongated hole 17 provided in the fixed barrel 1 and engages with a notch 30c of the cam cylinder 30.

That is, when the zoom ring 18 is rotated, the cam cylinder 30 is rotated by the pin, and zooming is performed.

As described above, according to this embodiment, the cam cylinder, which was conventionally made by machining, is made of a thin material molded into a cylindrical shape, such as a thin stainless steel plate or resin, thereby significantly reducing the processing cost of the cam cylinder. In addition, as the cam cylinder becomes thinner, the lens moving device can be made smaller.

Moreover, although the material of the cam cylinder is described as a stainless steel plate, other steel plates or resin materials having the required performance may be used.

Further, the cam groove formed in the cam cylinder is not limited to being formed by press working, but may be formed by etching, for example.

Effects of the Invention As described above, the present invention reduces deformation due to molding of the first lens holding frame and the second lens holding frame movable in the optical axis direction, and the first cam and the second cam. By providing a drive member formed in a thin plate shape with auxiliary grooves arranged in such an effective manner and formed into a cylindrical shape centered on the optical axis, an inexpensive and compact lens moving device can be provided.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a cam cylinder according to an embodiment of the present invention, and Fig. 2 shows the first cam groove and the second force J4 after molding of a cam plate of a third type door with a different arrangement of auxiliary grooves. FIG. 3 is a partial cross-sectional view showing the main parts of a conventional lens moving device. 1...Fixed cylinder, 5a, 5b, 5c...
Guide ball, 8...First lens holding frame, 2
0... Second lens holding frame, 5, 30...
...Cam tube. Name of agent Patent attorney Toshio Nakao Haka1 Figure 0d Figure 2 (/Jml

Claims (1)

[Claims] A first lens holding frame and a second lens holding frame movable in the optical axis direction, a first cam for driving the first lens holding frame, and a first cam for driving the second lens holding frame. a second cam, and a thin plate-like cylindrical shape having auxiliary grooves arranged effectively to reduce deformation due to molding of the first cam and the second cam, and having a cylindrical shape centered on the optical axis. A lens moving device comprising a driving member.