JPS59116627A - Driving device of photographic lens - Google Patents

Abstract

PURPOSE:To use a space effectively to make the device small-sized, by fitting a cylindrical movable coil member, which is moved linearly in the axial direction when electric power is supplied, to a cylindrical fixed permanent magnet and providing a lens unit on them as one body and driving the lens unit. CONSTITUTION:When a release button is depressed, the in-focus position of an optical system of a lens unit 29 is discriminated; and if it is placed in the closest distance, electric power is supplied to a coil 16 to move a cylindrical movable coil member 15 forward. Then, the lens unit 29 is moved forward against a spring 31, and its front end 25 is brought into contact with an inside end face 19a, namely, a point P' of a cylinder frame 19 and is fixed. If the optical system is placed in the far distance, the cylindrical movable coil member 15 is moved backward, and the lens unit 29 is moved backward against a spring 32, and a shutter supporting plate 12 is brought into abutment to inside end faces 5a and 6a of cylindrical yokes 5 and 6 namely, a point P and is fixed. When the in- focus position is determined, a shutter 13 is operated to perform the exposure operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photographing lens drive device that linearly drives a lens unit using electromagnetic force to enable two-focus operations and the like.

Conventionally, when driving a lens unit for a focusing operation or the like, there have been two methods: one that uses a motor as a driving source, and the other that uses electromagnetic force as a driving source.

In the former case, as is used in lens-shift cameras, after shooting is complete, the shooting lens is energized to an infinite distance position when the film is advanced, and the distance measurement signal determined by the distance measurement signal at the time of shooting is energized. The method of moving the photographic lens to the position by motor drive, and the Δ of -eye reflex camera.
As seen in the F device, there was a method in which the photographing lens was driven by changing the rotation amount and direction of the motor depending on the distance measurement signal, but both methods involved a gear reduction device or a device that converted rotary operation into linear operation. Therefore, it has become difficult to incorporate it into modern cameras, which are becoming smaller and lighter.

In addition, in the case of the rear fj, since it is an electromagnetic drive system, the possible
Depending on the direction and amount of current flowing through the coil section (A), some additional devices such as a controller drive system can be made unnecessary.

In this sense, although it was possible to downsize the device, the driving force of the lens unit was also reduced, making it impractical. That is, the magnitude of the electromagnetic force in the electromagnetic drive device is as follows, assuming that the current is constant.

Although it is proportional to the effective length of the coil in the magnetic field, in the case of conventional electromagnetic drive devices, the fixed permanent magnet and the movable coil member are arranged so as to face each other in a plane.

Moreover, since a space necessary for the optical system is provided in the center of the coil, it is extremely difficult to increase the effective length of the coil.

This invention is intended to solve the above problems, and includes 9 fixed permanent magnets arranged in a cylindrical shape, and 2 fixed permanent magnets fitted into the fixed permanent magnets.
By providing a cylindrical moving coil member that moves linearly in the axial direction when energized and a lens unit that is driven integrally with the cylindrical moving coil member, the effective length of the coil can be extremely large, resulting in a large electromagnetic force. It is an object of the present invention to provide a photographic lens driving device which has a linear drive and effectively utilizes a small amount of space.

Next, the present invention will be described based on one embodiment not shown in the accompanying drawings.

1 is a lens barrel, and a cylindrical yoke 2 provided with a groove 2a is fixed to the inner surface of the base of the lens barrel 1. 3
．． Reference numeral 4 designates fixed permanent magnets disposed in a cylindrical shape in two inner and outer holding cylinders 5 and 6 which are fitted into the groove 2a of the cylindrical yoke 2 with a certain gap 1 therebetween. , 4 are not shown, but of course they may themselves be cylindrical. It is necessary that the facing surfaces of the fixed permanent magnets 3.4 facing inside and outside have mutually different polarities. Reference numeral 7 designates a lens frame for rear lens groups 8a and 8b, and the lens frame 7 is slidably supported by a flange portion 2b provided on the inner diameter surface of the cylindrical yoke 2 via a ball bearing 9. 10 is a spacer 10a that holds between the lens i group 8a and Bb.
11 is a holding member for preventing the ball bearing 9 from falling off. I
Reference numeral 2 denotes a support plate for the shutter 13, and the support plate 12 is provided integrally with the lens frame 7. 14 is a cylindrical body protruding from the rear surface of the shutter support plate 12, and is fitted into the gap β between the inner and outer fixed permanent magnets 3.4. Reference numeral 15 denotes a cylindrical moving coil member composed of the cylindrical body 14 and a coil 16 wound around its outer periphery. 17 is a front lens group 18a.

In the lens frame 18b, the lens frame 17 is slidably supported via a ball bearing 20 on the inner diameter of a cylindrical frame 19 fixed to the inner surface of the tip of the lens barrel l. 21 is a front frame which also serves to prevent the ball bearing 20 from falling off; 22
is a holding member for the front lens groups 18a and 18b. Reference numeral 23 denotes a fixed permanent magnet for electromagnetically driving the shutter 13, and the fixed permanent magnet 23 is arranged in a holding frame 24 that is integrated with the front group lens frame 17. A yoke 25 is attached to the front surface of the fixed permanent magnet 23 for driving the shutter, and a yoke 26 is provided behind the fixed permanent magnet 23 with a certain gap therebetween. A plurality of plate-shaped movable coil members 27 and 28 are interposed in the gap between the fixed permanent magnet 23 and the yoke 26. One side of the plate-shaped movable coil members 27 and 28 is for driving the shutter.

The other one is designed to function as a control.

Reference numeral 29 denotes a lens unit formed by integrally connecting the rear group lens frame 7 and the front group lens frame 17 via a connecting member 30, and the lens unit 29 is configured such that the cylindrical movable coil member 15 receives electromagnetic power when energized. The lens unit 29 is driven linearly in the axial direction (back and forth as it moves) by force.
The inner end surfaces 5a and 6a of the cylindrical frame 19 fixed to the inner surface of the tip of the lens barrel 1 are simply referred to as P'.
The range is defined as P-P'. 31 is a wing that bends and presses the lens unit 29 backward; 32
is a spring that presses the lens unit 29 forward.

The spring forces of both springs 31 and 32 are balanced, and when the cylindrical movable member is in a non-energized state, the lens unit 29 is held at the midpoint of its drive range pp'.

Next, the operation of the camera incorporating the photographic lens driving device according to the present invention will be explained.

First, when you point the camera at the subject and press the release button (not shown), the distance measuring circuit (not shown) etc. will determine whether the optical system of the lens unit 29 is at the normal focus or closer to the subject. It is determined whether the object is close or far away.

In the case of close range, the coil 16 is energized to move the two cylindrical movable coil members 15 forward.

As a result, the lens unit 29 moves forward against the spring 31, and the yoke 29 forming the front end of the lens barrel interior I.29 moves forward.
is the inner end surface 19a of the cylindrical frame 19.

In other words, it is fixed by abutting against P'. On the contrary, in the case of a long distance, the cylindrical movable coil member 15 bends backward, and the lens unit 29 moves backward against the spring 32.
The shutter support plate 12 constituting the rear end of the lens unit 29 is fixed in contact with the inner end surfaces 5a and 6a of the cylindrical yokes 5 and 6, that is, the rear point P. The lens unit 29 is moved forward or backward by changing the direction of current when the cylindrical movable coil portion 15 is energized. It goes without saying that the direction of this current is determined by the polarity of the fixed permanent magnet 3.4 arranged in a cylindrical shape.

In addition, when the focusing position of the optical system is at the normal focal position, the position where the balance of the wings 31 and 32 is maintained is maintained, so the two cylindrical movable coil members 15 have CI).
The U control tt3t +R (not shown) prevents energization.

When the lens barrel interior 1-29 operates as described above and the second focal position is determined, an exposure signal is sent by the exposure control circuit (not shown), and the plate-shaped movable coil members 27 and 28 are energized. The shack 13 is activated by a constant aperture value and a second time control.

After the exposure control is completed, the two cylindrical movable coil members 15
When the power to the lens unit 29 is cut off, the spring 31
or 32, the camera is returned to the midpoint (initial position) and waits for the secondary photographing.

As described above, according to the present invention, there are three fixed permanent magnets arranged in a cylindrical shape, and the magnet is fitted into the fixed permanent magnets.

It is equipped with a cylindrical moving coil member that moves linearly in the axial direction when energized, and a lens unit that is driven integrally with the cylindrical moving coil member, so the lens unit can be moved back and forth for focusing operation. The device to move it is extremely simple,
Since no special control mechanism is required, it can be easily miniaturized.
It can also be sufficiently stored inside the lens barrel.

In addition, since it consists of a combination of a fixed permanent magnet arranged in a cylindrical shape and a cylindrical moving coil member, the effective length of the coil is greatly increased compared to the case of conventional electromagnetic drive devices. Even if electric current is consumed, the driving force is much greater and the efficiency is also improved, which brings about various excellent effects.

Note that this invention has the above-described configuration.

It can be easily applied not only to the focusing operation of a photographic lens, but also to a collapsing device, zooming, etc., as long as the device can move in a straight line. Further, in the above embodiments, the lens unit is considered to have the rear group lens frame and the front group lens frame as one unit, but it goes without saying that either one of them may be used.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. 2. FIG. 1 is a sectional view of the main part in the direction of the optical axis, and FIG. 2 is a sectional view of the main part in the direction perpendicular to the optical axis. 3./V-- Fixed permanent magnet 15 Cylindrical moving coil member 29- Lens unit. Patent applicant: Roku Konishi Photo Industry Co., Ltd. Procedural stress letter (method) April 28, 1980 Commissioner of the Patent Office Kazuo Wakasugi 1 - Indication of the case 1988 Patent application No. 225056 2 - Name of the invention Photography Lens drive device 3-? Relationship with the case of a person under pressure Patent applicant address 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name
Konishiroku Photo Industry Co., Ltd. Representative Nobuhiko Moto 4-Agent ■151 Address 2-5-1 Yoyogi, Shibuya-ku, Tokyo 6-? II
i-Correct Subject Application and Specification 7 - Contents of Amendment

Claims (1)

[Scope of Claims] (11) A fixed permanent magnet arranged in a cylindrical shape, a cylindrical movable coil member that fits into the fixed permanent magnet and moves linearly in the axial direction when energized, and the cylindrical movable coil member. and a lens unit that is driven integrally with a lens unit. (2) The fixed permanent magnets are provided dually inside and outside. Between the fixed permanent magnets, the cylindrical movable coil member is disposed. The photographic lens driving device according to claim 11, wherein: