JPH0715531B2 - Zoom lens moving device for camera - 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 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 is rotated around the optical axis to focus lenses L1 and L.
2, L3 is extended in the optical axis direction. The focusing lenses L1, L2, L3 are pressed and fixed by the lens presser 3 and the spacer 4. The variable power lens groups L4, L5, L6 are the first lens holding frame 8
And is fixed to the first lens holding frame 8 by screwing the screw portion 9a of the pressing ring 9 of the variable power lens L4 into the screw portion 8a of 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 is movably supported in the optical axis direction by inserting the guide pole 6a into the elongated hole portion 8b and engaging the guide pole 6c with the cutout portion 8c. Similarly, the second lens holding frame 10 is also supported so as to be movable in the optical axis direction by inserting the guide pole 6b into the elongated hole portion 10a and engaging the guide pole 6c with the cutout portion 10b. The cam frame 5 is a first cam groove 14 for driving the first lens holding frame 8 and the second lens holding frame 10 in the optical axis direction.
And a second cam groove 15 is provided. In the first cam groove 14 and the second cam groove 15, in order to restrict the positions of the variable power lens groups L4, L5, L6 and the correction lens L7 on the optical axis, respectively, the first lens holding frame 8 and Pins 12 and 13 which are respectively planted in the second lens holding frame 10 are engaged with each other, and pins 16 are planted in the cam barrel 5 so as to penetrate through the elongated hole 17 to the outside of the fixed barrel 1. It is protruding. 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. The positions of the magnification lens groups L4, L5, L6 and the correction lens L7 are regulated by the first cam groove 14 and the second cam groove 15 to perform zooming. 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 up until now, high precision processing was performed by machining such as lathe processing and milling. .

However, the above-described mechanically processed cam cylinder has a drawback that the processing cost associated with high precision processing is expensive. 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-mentioned problems, the present invention uses a cam cylinder, which has been conventionally processed by an expensive construction method such as lathe processing and milling processing, to press work such as a thin stainless steel plate. The present invention provides a small-sized and inexpensive lens moving device by replacing it with a flexible member that can be formed by.

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 thin plate having a first cam for driving the lens holding frame and a second cam for driving the second lens holding frame, and the first cam and the second cam in the vicinity of the end face. The surface on which is formed is a surface provided with a driving member molded at different heights in a plane parallel to the optical axis.

Effect of the Invention According to the present invention, the cam cylinder having the above-described structure is formed by a flexible member that can be formed by press working such as a thin stainless steel plate to move the lens and position it at a predetermined position. The processing cost can be greatly reduced, and other components can be downsized with the thinning of the cam barrel, so that a small and inexpensive lens moving device can be obtained.

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 barrel according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along a plane X parallel to the optical axis of the cam barrel. In FIG. 1, the cam barrel 30 is the first cam 30a.
And a second cam 30b, which is a thin stainless steel plate molded into a predetermined diameter. Further, the cam barrel 30 is a bead having a triangular cross-sectional shape as shown in FIG. 2 in order to increase rigidity.
31 and 32 are formed. Then, it is rotatably mounted on the inner peripheral portions of both ends of the fixed body 1 shown in FIG. At this time, the pin 1 of the first lens holding frame 8 is inserted into the cam grooves 30a and 30b.
2 and the pin 13 of the second lens holding frame 10 are engaged with each other. A pin (not shown) is planted in the zoom ring 18 having the knob 20 and penetrates a long hole 17 provided in the fixed barrel 1 to engage with a cutout portion 30c of the cam barrel 30. That is, when the zoom ring 18 is rotated, the cam cylinder 30 is rotated and zooming is performed.

As described above, according to the present embodiment, a flexible material that can form a cam cylinder that has been conventionally machined by press working,
For example, by constructing a thin stainless steel plate,
The processing cost of the cam barrel can be greatly reduced, and the lens moving device can be downsized as the cam barrel becomes thinner.

The shape of the bead has been described as a triangle, but the shape is not limited as long as it meets the purpose of increasing the rigidity. Therefore, it may be a circular arc or a trapezoid. Similarly,
If the number of beads meets the above-mentioned purpose, the number of beads is not limited. Therefore, for example, a bead may be additionally formed in the vicinity of the cam groove in order to increase the rigidity in the vicinity of the cam groove.

Further, although the material of the cam cylinder is described by using the stainless steel plate, the material is not limited to this as long as the material has the required performance, and other steel plates or resin materials may be used.

The cam groove formed in the cam groove 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 provides a first lens holding frame and a second lens holding frame that can move in the optical axis direction, and a first cam for driving the first lens holding frame. A thin plate shape having a second cam for driving the second lens holding frame, and the vicinity of the end surface is in a plane parallel to the optical axis with the surface on which the first cam and the second cam are formed. By providing the driving members molded at different heights in 1., it is possible to provide an inexpensive and compact 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, FIG. 2 is a sectional view taken along the plane X of the cam barrel, and FIG. 3 is a partial sectional view showing a main part of a conventional lens moving device. Is. 1 ... Fixed barrel, 6a, 6b, 6c ... Guide pole, 8 ... First lens holding frame, 10 ... Second lens holding frame, 5, 30 ...
Cam barrel, 31,32 ... bead.

Claims (1)

[Claims] 1. A first zoom lens holding frame and a second zoom lens holding frame which are movable in the optical axis direction of a camera, and a first hole formed by a through hole for driving the first zoom lens holding frame. The first cam and the first cam and the second cam formed by a second cam formed by a through hole for driving the second zoom lens holding frame for driving the first cam and at least near the end face. For a camera, characterized in that a strip-shaped reinforcing groove having a convex or concave shape as compared with the surface on which the second cam is formed is provided with a drive member formed in a direction substantially perpendicular to the optical axis direction. Zoom lens moving device.