JPS6194012A - Focusing device of lens barrel - Google Patents

Abstract

PURPOSE:To eliminate the influence of the deviation of a lens from the optical axis by connecting levers to >=2 points on the outside periphery of a moving lens group, moving the levers to move the moving lens group in the optical axis direction and focusing the lens without rotating the same. CONSTITUTION:A moving lens holder 12 is pressed via steel balls 16 energized by a leaf spring 15 to a lens barrel 13 and the levers 19 are attached to >=2 points on the outside periphery of the holder 12. The levers 19 are constituted rotatable around a shaft 20 and are fixed at one end to cam levers 21 connected to a disk cam 22 provided with a gear. When the cam 22 is rotated by a driving motor, the levers 19 are rotated around the shaft 20 via the lever 21 and the holder 12 is axially moved and focussed. The image having no turning fluctuation of the image is thus obtd. even if there is the deviation of the lens from the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a focusing device for a lens barrel used in a camera or the like.

The configuration of the conventional example and its problems The configuration of the focusing mechanism section in the conventional example of the focusing device is explained in the first example.
As shown in the figure.

In FIG. 1 on page 2, after the focusing lens holder 1 has set the back focus on the movable lens barrel 2, it engages with the helicoid 4 provided on the movable lens barrel 2, which is fixed with the bank focus fixing screw 3. By fitting them together, the movable lens barrel 2 is incorporated into the fixed lens barrel 6.

A variable power lens holder 6 is attached to a fixed lens barrel 5 by a shaft 7.
incorporated into. A pin 9 provided on the variable power lens holder 6 is incorporated into a cylindrical cam 8 incorporated into the fixed lens barrel 6.

Ten gears provided on the movable lens barrel 2 are attached so as to mesh with a drive gear 11 that transmits driving force from a drive section having a drive source such as a motor capable of decelerating or speeding up.

As the driving gear 11 rotates, the gear A10 rotates, and rotational force is generated in the movable lens barrel 2. When the movable lens barrel 2 rotates, the helicoids 4 provided on the movable lens barrel 2 and the fixed lens barrel 5 engage with each other, so the movable lens barrel 2 moves in the axial direction while rotating, and comes to a focused point. It has become.

3 to 2 However, in such a conventional focusing mechanism device using a helicoid 4, since the movable lens barrel 2 and the vericoid 4 provided on the fixed lens barrel 5 are engaged with each other, the precision of the helicoid 4 cannot be improved. In addition, it required skill to engage the helicoids 4 during assembly, resulting in high costs.

Also, since the movable lens barrel 2 rotates, the lens rotates when focusing, so if the lens is misaligned with the optical axis,
There was a drawback that the image of the subject rotated.

Furthermore, there is also a disadvantage in operation that if foreign matter or the like gets into the helicoid 40, the helicoid 4 will not rotate smoothly.

OBJECTS OF THE INVENTION The present invention provides a focusing device that eliminates the above-mentioned conventional drawbacks, is inexpensive and easy to assemble, and allows easy focusing by moving the lens straight in the axial direction without rotating it. With the goal.

Structure of the Invention In the present invention, the mechanism for moving the lens to focus does not use a helicoid, but instead uses a cam or lever to move the lens straight in the axial direction instead of rotating it. .

DESCRIPTION OF THE EMBODIMENTS A focusing device for a lens barrel according to an embodiment of the present invention is shown in FIGS. 2 and 3.

In FIGS. 2 and 3, the movable lens holder 12 is
It is built into the lens barrel 13 so that it is pressed against the lens barrel 13 via a steel ball 16 by the elastic force of a leaf spring 16 that is elastically attached to the lens barrel 13 with screws 14 .

The guide pin 17 allows the movable lens holder 12 to
After being attached to the lens barrel 13, the guide groove 1 provided in the lens barrel 13
8 is assembled properly.

The variable power lens holder 6 is assembled into the lens barrel 13 by a shaft 7. The barrel cam 8 built into the lens barrel 13
A pin 9 provided on the variable power lens holder 6 is incorporated into the lens.

6. The vane levers 19 are installed in grooves at two positions on the outer periphery of the movable lens holder 12. Moreover, the lever 19 is
It is rotatable about the shaft 20 as a fulcrum, and the shaft 2
0 is fixed to the lens barrel 13 by a bearing or the like. One end of the cam lever 21 is fixed to the cam lever 19, and the other end is connected to a cam groove of a geared disc cam 22. The cam lever 21 has a long arc-shaped screw hole 23 in the center of the shaft hole.
is provided, and is fixed to the lever 19 with a back focus adjustment screw 24 after back focus adjustment.

Next, the operation will be described. When the geared disc cam 22 is rotated by the drive of a motor, etc., the lever 19 rotates about the shaft 20 via the cam lever 21, and the movable lens holder 12 is thereby moved in the axial direction. Move and focus.

Furthermore, the movable lens holder 12 is pressed against the lens barrel 13 by a steel ball 16 via a leaf spring 15, so that when the movable lens holder 12 moves in the axial direction, the lens barrel 13
Even if there is play between the vane movable lens holder 12 and the lens holder 12, the vane movable lens holder 12 can be moved in the axial direction without falling down.

Therefore, with this configuration, υ focusing can be achieved by moving the lens straight without using a helicoid mechanism that requires high precision and without rotating the lens. Even if there is a deviation from the optical axis of the lens, an image can be formed without rotational fluctuations.

Moreover, since the high-precision processing required for helicoid processing is no longer required, costs can be reduced, and the helicoid assembly work, which requires skill, is no longer required, resulting in improved workability.

Effects of the Invention As described above, according to the present invention, it is possible to focus by moving the movable lens holder straight forward without rotating it, so even if there is a deviation from the optical axis of the lens,
Image formation without image rotational fluctuations can be obtained.

In addition, since there is no helicoid processing that requires high precision, the cost is reduced, and there is no need to assemble helicoid fittings that require skill, improving workability.

了・＼- Also, back focus adjustment can be done without rotating the lens holder as in the conventional case, so it is possible to obtain effects such as improved work efficiency.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional camera barrel focusing device;
The figure is a sectional view of a focusing device of a camera barrel in one embodiment of the present invention, and FIG. 3 is a perspective view of the same device. 12...Moving lens holder, 13...
Lens barrel, 14...screw, 15...plate spring,
16... Steel ball, 17... Guide pin,
18... Guide groove, 19... Lever, 2
0...Shaft, 21...Cam lever, 22...Disc cam, 23...Long screw hole, 24...Back focus adjustment screw. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A movable lens group is mounted in the lens barrel so as to be freely axially oriented, a guide pin is provided on the movable lens group, the guide pin is fitted into an axial guide hole provided in the lens barrel, and an elastic body is attached to the lens barrel. and press it against the lens barrel, and connect levers to two or more positions on the outer periphery of the movable lens group, and drive the lever to move the lens group in the optical axis direction without rotating the lens. A focusing device for a lens barrel, characterized in that the focusing device focuses on the lens barrel.