JPS62189414A - Lens moving device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive and small-sized lens moving device by providing the first and the second lens holding frames, and a driving member which is shaped like a thin plate, and also, whose end face vicinity has been molded to a different height in a plane being parallel to an optical axis, from the surface on which the first and the second cams have been formed. CONSTITUTION:A cam cylinder 30 forms the first cam 30a and the second cam, 30b, and it is a stainless steel plate of a thin wall which is molded to a prescribed diameter. Also, as for the cam cylinder 30, beads 31, 32 having a triangular sectional shape are formed in order to increase the rigidity, and installed so as to be freely turnable to the inside peripheral part of both ends of a fixed drum 1. In such a case, to cam grooves 30a, 30b, a pin of the first lens holding frame and a pin of the second lens holding frame are engaged, respectively. To a zoom ring having a control, a pin is provided vertically, penetrates a long hole which has been provided on the fixed drum, and engaged to a notch part 30c of the cam cylinder 30. That is to say, when the zoom ring is turned, the cam cylinder 30 is turned and zooming is executed.

Description

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

2. Description of the Related Art Conventional zooming mechanisms for lens barrels generally use a cam barrel attached to a fixed barrel to move the lens.

An example of the above-mentioned conventional lens moving device 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 installed in fixed barrel l
The helicoid screw 2a provided on the focusing ring 2 is screwed into a, and the focusing lens L is rotated around the optical axis.
1, L2, and L3 in the optical axis direction. Focusing lens L1
, L2, and L3 are pressed and fixed by a lens holder 3 and a spacer 4. The variable power lens groups L4, L5, and L6 are inserted into the first lens holding frame 8, and the threaded portion 9a of the holding ring 9 of the variable power lens L4 is inserted into the threaded portion 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 IO and fixed by the pressing force of the presser spring 11. The first lens holding frame 8 is supported movably in the optical axis direction by having a guide ball 6a inserted into an elongated portion 8b and engaging the guide ball 6c with a notch portion 8C. Similarly, the second lens holding frame 10 is also supported movably in the optical axis direction by having a guide ball 6b inserted into the elongated portion 10a and engaging the guide ball 6C with the notch portion 10b. 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 groove 14
and the second cam groove 15 respectively include a variable magnification lens group L4,
In order to regulate the positions of L5, L6 and the correction lens L7 on the optical axis, bins 12 and 13 respectively installed in the first lens holding frame 8 and the second lens holding frame 10 are engaged. At the same time, a bottle 16 is implanted in the cam cylinder 5 and projects to the outside of the fixed cylinder 1 through an elongated hole 17. Handpick 2
A zoom gear 21 is fitted into the zoom ring 18 having a diameter of 0 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 cylinder 5 is rotated, so that the positions of the variable power lens group L4; Zooming is regulated by the cam groove 14 and the 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. Furthermore, it is impossible to eliminate deformation and distortion of the cylinder due to cam groove machining in a cam cylinder formed by a cam groove obtained by penetrating the inside of the cylinder Φ. 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.

Problems to be Solved by the Invention In view of the above-mentioned problems, the present invention replaces the cam cylinder, which has conventionally been processed by expensive methods such as lathe processing and milling, with press processing such as a thin stainless steel plate. The objective of the present invention is to provide a small and inexpensive lens moving device by replacing the flexible member with a flexible member that can be formed from.

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 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 near the end face. The driving member is formed at a different height in a plane parallel to the optical axis.

According to the above-described structure, the cam tube for moving the lens and positioning it at a predetermined position is constructed of a flexible member that can be formed by press working, such as a thin stainless steel plate. It is possible to reduce the processing cost to a large extent, and to make the cam cylinder thinner, it is possible to downsize the other constituent members. Therefore, the lens moving device can be made small and inexpensive.

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 barrel according to an embodiment of the present invention, and FIG. 2 is a sectional view of the cam barrel taken along a plane X parallel to the optical axis. In FIG. 1, the cam cylinder 30 is the first cam 3.
0a and a second cam 30b, and is a thin stainless steel plate molded to a predetermined diameter. In addition, the cam cylinder 30 is formed with grooves 31 and 32 having a triangular cross-sectional shape as shown in FIG. 2 in order to increase the rigidity. Then, it is rotatably attached to the inner peripheral portions of both ends of the fixed barrel 1 shown in FIG. 3.

At this time, the pins 12 of the first lens holding frame 8 and the pins 13 of the second lens holding frame 10 are engaged with the cam grooves 30a and 30b, respectively. Zoom ring 1 with handle 20
A bottle (not shown) is installed in 8, passes through an elongated hole 17 provided in the fixed shell, and engages with a notch 30c of the cam cylinder 3o. That is, when the zoom ring 18 is rotated, the cam cylinder 30 is rotated and zooming is performed.

As described above, according to this embodiment, a flexible material that can be used to form a cam cylinder, which was conventionally made by machining, by press working, etc.
For example, by constructing it from a thin stainless steel plate,
The machining cost of the cam cylinder can be greatly reduced, and the lens moving device can be downsized by making the cam cylinder thinner.

Although the shape of the bead has been described as a triangle, there is no restriction on the shape as long as it meets the purpose of increasing rigidity. Therefore, it may be an arc or a trapezoid. Similarly,
The number of beads is not limited in any way as long as it meets the above purpose. Therefore, for example, a bead may be additionally formed near the cam groove in order to increase the rigidity near the cam groove.

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

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

Effects of the Invention As described above, 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 cam for driving the first lens holding frame. A thin plate 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 respect to the surface on which the first cam and the second cam are formed. By providing the drive members molded at different heights, it is possible to provide an inexpensive and compact lens moving device.

[Brief explanation 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 of the cam barrel on plane X, and FIG. 3 is a partial sectional view showing the main parts of a conventional lens moving device. It is. 1...Fixed cylinder, 6a, 6b, 6c...
Guide ball, 8...First lens holding frame, l
O... Second lens holding frame, 5, 30...
...Cam cylinder, 31.32...Bead.

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 drive member formed of a thin plate shape having a second cam formed thereon, and having a height near the end surface that is different from the surface on which the first cam and second cam are formed in a plane parallel to the optical axis. A lens moving device characterized by comprising: