JPS60260926A - Electromagnetic driving device for driving and controlling light quantity control member and photographing lens - Google Patents

Abstract

PURPOSE:To obtain the titled compact electromagnetic driving device of a compact structure, by providing a movable coil member for controlling light quantity and another movable coil member for driving and controlling photographing lens within one gap formed by a common magnetic field. CONSTITUTION:The 1st yoke 2 is firmly fitted to a holding frame 4 by utilizing the attracting force of a permanent magnet 5 under a condition where the holding frame 4 is controlled in position. In addition, the 2nd yoke 3 is also firmly fitted to the frame 4 by utilizing the attracting force of the magnet 5 under a position-controlled condition. Therefore, the gap of the magnetic circuit, which is formed by the permanent magnet 5 and 2nd yoke 3 and into which the 1st and 2nd movable coil members 6 and 7 are inserted, is always maintained constantly. The 1st movable coil member 6 repeats reciprocating motions little by little upon receiving the pulse signal of a distance measuring circuit assembled in the main body of a camera and transmits the power to a focussing device (not shown in the figure) through a pin 10 planted in the member 6.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a camera that uses electromagnetic force obtained by a fixed permanent magnet and a moving coil member as a driving source to open and close shutter blades and to operate a photographic lens. This invention relates to an electromagnetic drive device.

[Prior art]

BACKGROUND ART Conventionally, when driving a lens unit in a camera for focusing operations, etc., there have been two methods: one using a motor as a driving source, and the other using electromagnetic force as a driving source.

In the former case, as used in lens-shutter cameras, after shooting is completed, the shooting lens is driven by a motor to a close distance position when the film is advanced, and the shooting lens is moved to the position determined by the distance measurement signal during shooting. There were two methods: one method used a spring force to return the lens, and the other method used a distance measurement signal, such as the one found in the AF system of an eye reflex camera, to drive the photographic lens by changing the rotation amount and direction of the motor. Because it is necessary to add a device that converts rotational action into linear action, it has become difficult to incorporate it into Kamechika's cameras, which are becoming smaller and lighter. Therefore, the latter electromagnetic drive is required for focusing operation of photographic lenses. However, shutter devices that use electromagnetic force are used because of their simple and compact structure in terms of force control, that is, the opening and closing operations of the shutter blades. The trend is strengthening.

In such an electromagnetic drive device that drives and controls both the focusing operation of the photographing lens and the opening and closing of the shutter blades, at least two or more members, that is, moving coil parts, driven by electromagnetic force are required, and they are Each must be placed in a magnetic field with an appropriate magnetic flux to receive the electromagnetic force.

For this reason, in the past, each moving coil member was configured to maintain its driving force by being placed individually within a magnetic field formed by a dedicated magnet, but this method requires a large number of parts and space. This becomes necessary and becomes an obstacle to miniaturization and cost reduction of cameras.

One way to solve this problem is to
A proposal has been made in Publication No. 8. In other words, a single row of permanent magnets is held in the middle of a pair of left and right yokes, and movable coil members are placed in the magnetic fields formed on both sides of the magnet, thereby saving parts and space. This method requires extremely difficult work to precisely align multiple permanent magnets, and if an error occurs in the installation, the strength of the left and right magnetic fields will be significantly imbalanced, causing functions such as focusing the photographic lens and operating the shutter to be disrupted. The result is that the process is not carried out smoothly.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic drive device for driving and controlling a light amount control unit and a photographing lens of a camera, which has a simple structure, is compact, and is low in cost.

[Structure of the Invention] ), 1 The present invention provides a structure in which the movable coil for controlling the amount of light and the movable filter for controlling the drive of the photographic lens are permanently attached so that the magnetic field strength corresponding to the driving force required for each can be obtained. It is constructed by sequentially arranging a magnet and a yoke within the same magnetic field, and it is possible to connect the moving coil member for light amount control and the moving coil member for photographing lens drive control into one gap formed by a common magnetic field. This is achieved by an electromagnetic drive device that drives and controls the light amount control section and the photographing lens, which are characterized by being disposed inside the camera.

〔Example〕

One embodiment according to the present invention is shown in FIGS. 1 to 4. FIGS. 1 to 4 show a typical example of the present invention. A first yoke 2 and a second yoke 3 are provided on the outer periphery of the body 1 to face each other via a holding frame 4 in which permanent magnets 5 are equally distributed along the circumference. In the cap between the second yoke 3 and the permanent magnet 5, there is a first movable coil part 6 which is a moving coil member for controlling the driving of the photographic lens and has a coil pattern 6a, and a first movable coil part 6 having a coil pattern 7a for controlling the light quantity. The second movable coil member 7, which is a movable coil part, has ring-shaped spacers 11a and 11 of two sizes, large and small, as shown in FIG.
They are arranged in a stacked manner so as not to interfere with each other. Note that the spacers lla and llb may be provided in a fixed or floating state with respect to the holding frame 4.

The first yoke 2 is fixed to the holding frame 4, and the holding frame 4 is attached to the holding frame 4.
is fixed by attraction using the attraction force of the permanent magnet 5 in a state in which the position is regulated, and furthermore, the second yoke 3 is attracted to this holding frame 4 by the attraction force of the permanent magnet 5 in a state in which the position is regulated. Fixed.

Therefore, the gap in the magnetic circuit between the permanent magnet 5 and the second yoke 3, in which the first and second moving coil members 6 and 7 are interposed, is always maintained at -.

The first movable coil member 6 repeats small reciprocating rotations in response to pulse signals from a distance measuring circuit built into the camera body, and is connected to a focusing device (not shown) via a bottle 1o implanted thereon. It is designed to transmit power.

Reference numeral 14 denotes a shutter blade provided between the second yoke 3 and the shutter base plate 15 disposed behind it. A pin 18 implanted in the second movable coil member 7 is engaged with the arcuate groove 17 provided on the side.

Therefore, when the second movable coil member 7 is rotated clockwise by electricity from a circuit built into the camera body, the shutter blade 14 is operated to the open side.

In this way, the magnetic field gap in the electromagnetic drive device of the present invention is determined by the dimensions of the holding frame 4 and the permanent magnet 50, so the machining accuracy is extremely high, and the magnetic field strength is also stable. It is possible to apply appropriate electromagnetic force, that is, driving force, to the coil portions 6 and 7, respectively.

Furthermore, since the first and second movable coil members 6 and 7 are kept apart by the spacers lla and llb, they are placed in an environment where they can rotate without interfering with each other and can fully exert their respective functions. It's dark.

FIG. 5 shows an example of a camera lens focusing device using the electromagnetic drive device of the present invention.

An electromagnetic drive device 100 is fixed to a lens barrel (not shown) of a camera, and a lens drive base plate 110 is attached to the front surface of the electromagnetic drive device 100 by screwing or the like to a flange portion 111 thereof.

A body 141 of a lens drive tube 140 is fitted into the inner surface of the body 112 of the lens drive base plate 110, and an outer peripheral portion 131 of a photographing lens frame 130 is fitted into the inner surface of the body 141 so as to be rotatable and slidable. and the outer peripheral portion 131
The three bottles 132 installed in the lens drive tube 140
three inclined grooves 142 provided in the body 141 of the lens drive base plate 110 and three straight grooves 11 provided in the body 112 of the lens driving base plate 110.
3 respectively, and protrudes slightly above the outer periphery of the body portion 112.

A cam member 120 is rotatably fitted to the base of the outer periphery of the body portion 112 of the lens drive base plate 110, and a step cam 1 consisting of three blocks is formed at the end of the body portion 121.
22 are installed so as to correspond to the bins 132 protruding from the body 112 of the lens drive base plate 110, respectively.

On the other hand, the tip of the swing bottle lO on the movable coil member for controlling the photographic lens that protrudes from the elongated hole 101 on the front surface of the electromagnetic drive device 100 is inserted through the elongated hole 114 on the flange portion 111 of the lens drive base plate 110. The flange portion 111
The upper part is connected to an arc-shaped member 116 provided so as to be able to swing in the circumferential direction along three guide rollers 115. That is, the swing motion of the moving coil member for controlling the photographic lens in the electromagnetic drive device 100 is transmitted to the arc-shaped member 116 via the swing bin 10.

A pawl 117 is provided at one end of the arc-shaped member 116 and is biased in the chronological direction by an elastic paulownia member (not shown). The mold wheel 123 is in mesh with the teeth, is pivotally supported by the lens drive base plate 110, and is supported by an elastic member (not shown).
The reverse rotation is prevented by the claw 124 which is biased clockwise.

Further, the shaft 71 of the driving motor 70 provided in the lens barrel is connected to the through hole 103 of the electromagnetic driving device 100,
Flange portion 1110 through hole 11 of the lens barrel 110
8 and fixed to the tip of the shaft 171 is the notched gear 14 of the lens drive barrel 140.
He has reached the point where he can mesh with 3. That is, the rotation of the drive motor 170 rotates the lens drive barrel 140, so that the photographing lens 133 attached to the lens frame 130 can be moved in the direction of its optical axis.

The operation in this example will be explained below.

When the control circuit energizes the photographing lens drive control movable coil member, that is, the first movable coil member 6, with a number of pulses corresponding to the detected distance in response to a signal from a distance measuring device in the camera body, the swing bin 10 Swings are repeated in the circumferential direction according to the number of pulses.

Therefore, the mold 117 reciprocates clockwise to move the step cam 122 corresponding to the detection distance to the bin 13 of the lens frame 130.
2 and stops, the drive motor 170 starts rotating clockwise in response to a signal from the control circuit and rotates the lens drive barrel 140 counterclockwise, so that the lens frame 130 The inclined groove 142 recedes linearly along the straight groove 113, and the bottle 13
2 comes into contact with a step corresponding to the detection distance of the step cam 122 to align the photographic lens 133 with its focus position,
Thereafter, the drive wheel 170 stops its rotation.

Then, when the shunter blades are opened and closed by energizing the light quantity control movable coil member 7 in the electromagnetic drive device 100 and the exposure is completed, the erasure drive motor 170 moves counterclockwise. The lens driving barrel 140 is returned clockwise to its initial position, that is, the lens frame 130 is returned to the most advanced position, and then stopped.

After that, the control circuit again controls the first moving coil member 6.
Pulse energization is started, and the pawl 117 further rotates the cam part 120 clockwise, until the highest step of the step cam 122 reaches the lens frame 1.
When the position facing the bin 132 of No. 30 is reached, the protrusion 125 provided on the circumferential surface of the step cam 1220 is at that position.
26 act to cut off the pulse current from the control circuit and stop the rotation of the cam member 120.

That is, the lens driving tube 1401 and the lens frame 130
, restore the cam part 1'120 to its initial state before photographing,
A position can be established in which the described action can be repeatedly initiated.

Note that 150 is a presser metal fitting that regulates the positions of the lens drive barrel 140 and the cam member 120 in the optical axis direction;
51 is added to the front surface of the lens driving base plate 110, while 161 is the one attached to the photographing lens 133.
A conversion lens that can change the focal length of the photographic lens 133 by combining the switching device 1
60 allows it to be inserted and removed on the optical axis.

1' FIG. 6 is a time chart showing a program for each operation in the photographing lens focusing device ζ of this example.

As is clear from the above description, the electromagnetic drive device of the present invention has a simple configuration because each moving coil member is arranged by effectively utilizing the magnetic flux distribution within the magnetic field, and the structure is simple. Since it is unitized so that it can be combined with the focusing mechanism in one bottle, assembly and adjustment are extremely easy.

〔Effect of the invention〕

The present invention provides a simple, high-performance, and compact N-magnetic drive device, which can be used to perform both the focusing operation of the photographic lens and the light amount control using electromagnetic force. This led to the realization of a compact camera.

[Brief explanation of the drawing]

1 to 4 are cross sections of the electromagnetic drive device of the present invention,
Plan and perspective views. FIG. 5 is a perspective view of a photographic lens focusing device using this electromagnetic drive device. Figure 6 is the time chart. 2.22・First yoke 3,23 Second yoke 4.24
Holding frame 5.25 Permanent magnet 6 First moving coil member 7 Second moving coil member 6a, 7a Coil pattern 1o... Swinging bin 11a, llb-7, pacer 14 - Shutter blade 15 Shutter base plate agent Patent attorney No. 1 ) Parent-in-law Figure 1

Claims (4)

[Claims] (1) Driving control of the light amount control member and the photographing lens, characterized in that the light amount control movable coil member and the photographing lens drive control movable coil member are disposed within one gap formed by a common magnetic field. electromagnetic drive device. (2) An electromagnetic drive for driving and controlling the light amount control member and the photographing lens according to claim 1, wherein one or two of the movable coil members are for driving and/or controlling the lens. Device. (3) The electromagnetic drive device according to claim 1 or 2, wherein the plurality of movable coil members are separated and arranged by a spacer for preventing interference. (4) Claim 1, characterized in that the movable coil member for driving the lens is disposed on the side closer to the permanent magnet.
The electromagnetic drive device according to items 1 to 3.