JPH079498B2 - 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.

2. Description of the Related Art A conventional zooming mechanism for a lens barrel generally uses a cam barrel mounted on a fixed barrel to move a lens.

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

FIG. 3 is a partial cross-sectional view of a main part showing a conventional example of a zoom lens barrel. Helicoid screw 1a provided on the fixed body 1.
Then, the helicoid screw 2a provided on the focusing ring 2 is screwed into the focusing ring 2, and the focusing ring L1, L2,
L3 is extended in the optical axis direction. The focusing lenses L1, L2, L3 are pressed and fixed by the lens holder 3 and the spacer 4. The variable power lens groups L4, L5, L6 are inserted into the first lens holding frame 8, and the screw portion 9a of the holding ring 9 of the variable power lens L4 is screwed into the screw portion 8a of the first lens holding frame 8. As a result, it is fixed to 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 pressing spring 11. The first lens holding frame 8 has a guide pole in the long hole 8b.
6a is inserted and is supported so as to be movable in the optical axis direction by engaging the guide pole 6c with the notch 8c. Similarly, the second lens holding frame 10 also has a guide pole 6b in the long hole 10a.
Is inserted and is supported so as to be movable in the optical axis direction by engaging the guide pole 6c with the notch 10b. The cam frame 5 includes a first lens holding frame 8 and a second lens holding frame 10.
A first cam groove 14 and a second cam groove 15 for driving the optical axis in the optical axis direction are provided. First cam groove 14 and second cam groove 15
Each of them has a variable power lens group L4, L5, L6 and a correction lens L7.
Pins that are respectively implanted in the first lens holding frame 8 and the second lens holding frame 10 in order to regulate the position on the optical axis of the
12 and 13 are engaged with each other, and a pin 16 is planted in the cam barrel 5 so as to penetrate the elongated hole 17 and project to the outside of the fixed barrel 1. In a zoom ring 18 having a knob 20, a zoom gear 21 is rotatably fitted around an optical axis, and a pin 16 is engaged with a long groove 19 formed on the inner peripheral 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 change in the first lens holding frame 8 and the second lens holding frame 10 is caused. Double lens group L4, L
The positions of 5, L6 and the correction lens L7 are regulated by the first cam groove 14 and the second cam groove 15, and zooming is performed.

As described above, the cam barrel is one of the important parts that regulates the position of each moving lens that requires high positional accuracy, so until now, high precision processing was performed by machining such as lathe processing and milling processing. .

However, the above-described mechanically processed cam cylinder has a drawback in that the processing cost is high due to high accuracy. Further, the cam cylinder formed by the cam groove obtained by penetrating the inside of the cylinder cannot eliminate the deformation and distortion of the cylinder due to the machining of the cam groove. Further, even if the cam cylinder is made thin to reduce the size and weight, there is a certain limit because the cylinder is deformed and distorted by the above-described processing.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In view of the above problems, the present invention replaces a cam cylinder, which has been conventionally processed by an expensive manufacturing method such as lathe processing and milling processing, with a thin plate member molded into a cylindrical shape. A small and inexpensive lens moving device is provided.

Means for Solving the Problems In order to solve the above problems, a lens moving device of the present invention includes a first lens holding frame and a second lens holding frame that can move in the optical axis direction, and the first lens holding frame. A first cam for driving the lens holding frame, a second cam for driving the second lens holding frame, and an effect to reduce deformation due to molding of the first cam and the second cam And a driving member formed in a cylindrical shape centered on the optical axis and having auxiliary grooves formed therein.

Action The present invention has the above-described configuration, and the cam cylinder for moving the lens to position the lens at a predetermined position is made of a thin member formed into a cylindrical shape, such as a thin stainless steel plate or resin, thereby reducing the processing cost of the cam cylinder. It is possible to make the lens moving device compact and inexpensive, since the other components can be made smaller as the cam barrel becomes thinner.

Embodiment A lens moving device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a cam cylinder in an embodiment of the present invention. In FIG. 1, the cam cylinder 30 is a thin stainless steel plate, and is pressed by pressing the first cam groove 30 in a flat plate state.
a, second cam groove 30b, notch 30c, auxiliary grooves 31a, 31b, 3
It is obtained by forming 1c and 31d and then rolling them by roll molding. FIG. 2 shows variations in the widths of the first cam groove and the second cam groove after molding of the three types of cam plates in which the arrangement of the auxiliary grooves is changed. As is apparent from the second, it can be seen that the variation of the cam plate 3 in which the auxiliary groove is effectively arranged is further suppressed.

The outer diameter of the cam barrel is rounded to a required size so as to be rotatably mounted on the mounting portion of the lens moving device. further,
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. The pins 12 of the first lens holding frame 8 and the pins 13 of the second lens holding frame 10 engage with the cam grooves 30a and 30b, respectively. Then, a pin (not shown) planted in the zoom ring 18 having the knob 20 penetrates the long hole 17 provided in the fixed barrel 1 and engages with the cutout portion 30c of the cam barrel 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 the present embodiment, the cam barrel, which has been conventionally machined by machining, is formed into a cylindrical shape by using a thin material such as a thin stainless steel plate or resin. In addition, the lens moving device can be downsized as the cam barrel becomes thinner.

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

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

EFFECTS OF THE INVENTION As described above, the present invention reduces the deformation of the first lens holding frame and the second lens holding frame that can move in the optical axis direction, and the molding of the first cam and the second cam. By providing the thin plate-shaped drive member formed with the auxiliary groove effectively arranged as described above and the cylindrical driving member centered on the optical axis, it is possible to provide an inexpensive and small lens moving device.

[Brief description of drawings]

FIG. 1 is a perspective view showing a cam barrel according to an embodiment of the present invention, and FIG. 2 is a diagram showing three types of cam plates in which auxiliary grooves are arranged differently.
FIG. 3 is a view showing width variations of the first cam groove and the second cam groove after molding, and FIG. 3 is a partial sectional view showing a main part of a conventional lens moving device. 1 ... Fixed barrel, 6a, 6b, 6c ... Guide pole, 8 ... First lens holding frame, 10 ... Second lens holding frame, 5, 30 ...
Cam barrel.

Claims (1)

[Claims] 1. A first lens holding frame and a second lens holding frame that can move in the optical axis direction, a first cam for driving the first lens holding frame, and a second lens holding frame. A second cam for driving the frame, and a thin plate shape having an auxiliary groove effectively arranged so as to reduce deformation due to molding of the first cam and the second cam. And a drive member molded into a cylindrical shape.