JPS6360433A - Motor-driven diaphragm device - Google Patents

Abstract

PURPOSE:To make the whole motor-driven diaphragm device small in size and light in weight, and to smoothly turn a rotor ring by a low voltage and a low current, by using a structure in which the rotor ring provided with a winding, and a diaphragm blade have been inserted and installed, and supported between a disk-shaped annular base member having a bearing part and a holder plate. CONSTITUTION:A motor-driven diaphragm device 1 is constituted of a disk- shaped annular base member 10 having a bearing part in the inside peripheral edge of one side face, a sheet-shaped annular rotor ring 20 which has been supported so as to be freely turntable by the bearing part of this base member 10, a flexible substrate 22 having a feeder part 28, plural pieces of diaphragm blades 30 for opening and closing an optical path (A) by interlocking with turning of the rotor ring 20, and a sheet-shaped annular holder plate 40 which is joined and fixed at a prescribed interval on one side face of the base member 10, and inserts and installs, and supports said rotor ring 20 and diaphragm blade 30, respectively. The rotor ring 20 is formed in a shape of an annular sheet by a metal of a non-magnetic material such as aluminum, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an electric aperture device for cameras such as still cameras and video cameras.

[Summary of the Invention] The present invention provides an electric diaphragm device in which a plurality of windings are mounted on a bearing portion on an inner peripheral edge of a disc-shaped base member having at least one side surface formed of a magnet, and a plurality of windings on a staggered side surface facing the magnet. By using a so-called moving filter, which rotatably supports a thin, annular, non-magnetic rotor ring and opens and closes the optical path using a plurality of aperture blades that move in conjunction with the rotation of the rotor ring, the number of parts can be reduced. The structure is simplified with less noise, making the entire device even smaller and lighter. Furthermore, the rotor ring can be rotated smoothly with low voltage and low current.

[Prior art] The lens barrel of cameras such as still cameras and video cameras has
Some cameras are equipped with an automatic diaphragm device that opens and closes an optical path by driving a plurality of diaphragm blades with a motor, thereby constantly providing appropriate exposure to an image pickup tube or the like according to the brightness of the field. With the recent demand for smaller and lighter camera barrels,
The aperture blade drive motor is built into the aperture device main body,
For example, Japanese Utility Model Application Laid-Open No. 58-170624 discloses an automatic diaphragm device in which the diaphragm blade drive motor is made small and flat so that it does not protrude from the lens barrel. This will be explained in detail with reference to FIG. 8. Reference numeral 50 is a so-called moving magnet type electric aperture device.

This electric diaphragm device 50 includes a first annular presser 51, a printed coil pattern 52a formed on both sides thereof, and a thin annular printed coil 52 disposed on one side of the first presser 51. Relief groove hole 53 for magnet loose fitting
a, and a plurality of rolling grooves 53 on one side.
b and a ball bearing portion 53d consisting of a ball 53c that transfers within the rolling groove 53b, a disc-shaped case 53 disposed on one side of the printed coil 52, and a ball bearing portion 53d formed on the side surface facing the ball bearing portion 53d. A cylindrical magnet 54 that is loosely fitted into a plurality of magnet loosely fitting escape groove holes 53a is fixed, and these magnets 54 are rotatable on the bearing part 53d with a predetermined clearance from one side of the printed coil 52. An annular rotor ring 5 supported by
5, a round hole 56a at the base end is rotatably supported by a pin 53e protruding from the outer peripheral edge of one side of the case, and a long hole 56b at the base protrudes from the other side of the rotor ring 55. A plurality of diaphragm blades 56 are engaged with and regulated by pins 55e that open and close the optical path in conjunction with the rotation of the rotor ring 55, and a spacer 57 is provided on one side of the first temporary presser foot 51.
．． It is comprised of an annular second presser plate 59 which is fastened and fixed at a predetermined interval via screws 58 or the like, and rotatably sandwiches the rotor ring 55 and the aperture blades 56, respectively. When a current is applied to the printed coil 52, the interaction between the current passing through the radially extending drive coil portion of the printed coil 52 and the magnetic flux of the magnet 54 causes the rotor ring 55 to be rotated around the ball bearing portion 53d of the case 53. For example, when the rotor ring 55 rotates clockwise, the aperture blades 56 open and open the optical path, and when the rotor ring 55 rotates counterclockwise, the aperture blades 56 close and close the optical path. It has become. As a result, a drive current is supplied to the printed coil 52 via a control circuit (not shown) equipped with a differential amplifier or the like by comparing an information signal corresponding to the field brightness with a reference value to obtain an appropriate exposure aperture aperture. By supplying power, it is possible to construct an electric diaphragm device that always provides proper exposure to the image pickup tube or the like according to the brightness of the field by opening and closing the optical path using the diaphragm blades 56.

[Problems to be Solved by the Invention] In the moving magnet type electric throttle device 50, in order to rotate the rotor ring 55 to which the magnet 54 is fixed, the ball bearing portion 53d has a complicated structure and is heavy.
A disc-shaped case 54 has a pair of press plates 51 and 59.
Since other components are also essential, the number of parts increases accordingly, making it impossible to sufficiently reduce the weight of the entire device.

In addition, since the thin plate annular printed coil 52 is used as the drive source for the rotor ring 55, the overall thickness of the device can be made relatively thin, or if the number of phases of the pattern 52a formed on the printed coil 52 is small. It is difficult to rotate the rotor ring 55 with low voltage and low current, and to solve this problem, increasing the number of phases of the pattern 52a has the disadvantage of increasing costs.

Therefore, this invention allows the rotor ring to rotate smoothly with low voltage and low current, and at low cost.
The present invention provides a moving coil type electric diaphragm device that is small and lightweight.

[Means for Solving the Problems] The electric diaphragm device of the present invention includes a disc-shaped base member in which at least one side surface is formed of a magnet and has a bearing portion on the inner peripheral edge of the one side surface; a thin annular non-magnetic rotor ring having a plurality of windings on a side facing the magnet, the windings being rotatably supported on the bearing part with a predetermined clearance from the magnet; a flexible substrate that is pulled out along the inner peripheral surface side of the base member in the optical path and supplies power to each of the windings; and a base end that is rotatably supported by a pin on the outer peripheral edge of one side of the base member. and a plurality of aperture blades whose tip end side is slidably stacked on the other side of the rotor ring and which opens and closes the optical path in conjunction with rotation of the rotor ring, and one of the base member. It is provided with a thin annular holding plate which is fastened and fixed to the side surface at a predetermined interval and rotatably supports the rotor ring and the aperture blades.

[Operation] A disc-shaped base member has a bearing portion that rotatably supports a rotor ring having a plurality of windings, and the rotor ring and the aperture blades are respectively rotatable; Because only one holding plate is required, the number of parts is significantly reduced, and the device is made smaller and lighter.When current flows through the windings of the rotor ring, torque is generated in the windings, and the rotor The ring rotates around the bearing portion of the base member through a predetermined angle. A plurality of aperture blades open and close the optical path in conjunction with the rotation of the rotor ring.

[Example] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 to 5, reference numeral 1 indicates a moving coil type electric diaphragm device. This electric diaphragm device 1 includes a disc-shaped base member IO having a bearing portion 10a on the inner peripheral edge of one side (upper surface in FIG. 1), and a thin plate rotatably supported by the bearing portion IQa of the base member IO. An annular rotor ring 20, a flexible substrate 22 having a power supply line portion 28, and a plurality of sheets that open and close an optical path (indicated by the symbol A in FIGS. 2 to 4) in conjunction with the rotation of the rotor ring 20. and a thin annular holding plate 40 which is fastened and fixed to one side of the base member 10 at a predetermined interval and rotatably supports the rotor ring 20 and the aperture blades 30, respectively. It consists of

The base member 10 is made of glass fiber-containing plastic and is formed into a circular disc shape except for a part of the circumferential side of one side, and the navigation bearing part 10a is formed in an arc shape along the inner circumferential edge of the one side. It has a protruding shape. This bearing portion 10a has a step portion tob on which the inner circumferential edge side of the other side surface (lower surface in FIG. 2) of the rotor ring 20 slides, and a vertical step portion tob on which the inner circumferential surface of the rotor ring 20 is slidably fitted. It has a portion 10c. For example, five thin fan-shaped ferrite magnets 11 are embedded in the circumference of one side of the base member 10 at approximately equal intervals. These ferrite magnets 11 are magnetized with magnetic poles N and S, as shown in FIG.

Further, a plurality of raised portions 10d having the same height as the vertical portion toe of the bearing portion 10a are formed protruding from the outer peripheral line of one side of the base member 10 so as to sandwich the ferrite magnet 11 therebetween. Pins 12 are vertically embedded in the top surfaces of these upright portions 10d. In addition, the elongated standing portion 1
In addition to the pin 12, a screw hole 13 is formed on the top surface of 0d. These base portion 110 and ferrite magnet 1
1 is a stator serving as a motor for driving the aperture blades. Incidentally, the pin 12 may be integrally molded with the base member IO in order to improve mass productivity.

The rotor ring 20 is formed into an FJ temporary shape from a non-magnetic metal such as aluminum. The inner diameter of the rotor ring 20 is approximately the same as the outer circumferential diameter of the vertical portion IQc of the bearing portion 10a, and the outer diameter is smaller than the outer circumferential diameter of the base member IO. For example, five pins 21 are protruded from one side of the rotor ring 20 (upper surface in FIG. 1). In addition, on the other side of the rotor ring 20 (lower surface in FIG. 1), for example, four drive windings 23 are connected via an arc-shaped flexible substrate 22, as shown in FIG. One brake winding 24 is fixed to each of the brake windings 24 and 24. These four drive windings 23 and one brake winding 24 form a drive circuit configured as shown in the plot diagram in FIG. Through the cooperation of the ferrite magnet 11, a braking voltage is generated in the braking winding 24 to apply braking to the drive winding 23, thereby controlling the rotation of the rotor ring 20 so that the aperture blades 30 can slowly open and close the optical path A. It has become. Incidentally, reference numerals 25 and 26 are amplifiers (operational amplifiers), and 27 is an input of a signal that controls the amount of opening and closing.

Furthermore, a power supply line portion 28 serving as a lead wire for supplying power to the drive winding 23 is integrally molded approximately on the inner side of the flexible substrate 22 . This power supply line section 28 is formed into a long rectangular plate shape with elastic force, and its base end 28
8a is erected and fixed perpendicularly to the other side surface of the rotor ring 20 by a resin presser plate 29, and extends into the optical path A from one notch lee of the bearing portion 10a of the base member 10. , the midway portion 28b passes through the other notch 10f of the bearing portion 10a along the inner circumferential surface side of the base member 10 in the optical path A, and the notch 10f passes through the other notch 10f of the bearing portion 10a.
It extends outward from a groove 10g formed in the upright portion 10d of the nearby base member 10. Therefore, this power supply line section 28
The midway portion 28b is held in the groove 10r of the upright portion 10d and fixed with an adhesive or the like, and has a semicircular shape so that its elastic force constantly urges the rotor ring 20 to rotate clockwise in FIG. It is curved and bent in an arc. These rotor ring 20 and each winding 23, 24 form a rotor as an aperture drive motor, and each winding 23, 24 is disposed opposite to the plastic magnet 11 of the base member 10 with a predetermined clearance. be.

A round hole 31 rotatably supported by the pin 12 of the upright portion 10d of the base member 10 is formed at the base end of the surface aperture blade 30, and the pin 21 of the rotor ring 20 is formed at the base. A slanted elongated hole 32 is formed to be engaged with and regulated by. Such a round hole 31. Five aperture blades 3 with long holes 32
0 are slidably stacked on one side of the rotor ring 20 so as to open and close the optical path A in conjunction with the rotation of the rotor ring 20.

The holding plate 40 is formed into an annular thin plate made of iron or the like and having substantially the same shape as the base member 10 .

It also serves as a yoke for the ferrite magnet 11 in order to increase its strength. Five holes 41 into which the pins 12 of the upright portion 10d of the base member 10 fit are formed in the outer peripheral edge of the presser plate 40, and the pins 21 of the rotor ring 20 are inserted into the central peripheral part. Five circular arc-shaped elongated holes 42 to be fitted are formed intermittently around the center of the optical path A. Furthermore, three recesses 43 (recessed toward the lower surface in FIG. 1) serving as spacers are formed on the outer peripheral edge of the holding plate 40. By screwing the screw 45 from the hole 44 formed in this recess 43 into the screw hole 13 of the upright portion 10d of the base member 10, the presser plate 40 is attached to the base member l.
The rotor ring 20 and the aperture blade 30 are each rotatably supported between the base member IO and the presser plate 40 by being fastened and fixed to one side of the base member IO at a predetermined interval.

According to the electric diaphragm device l of the above embodiment, when a current is applied to the drive winding 23 in the direction shown by the arrow in FIG.
A torque is generated which attempts to rotate the rotor ring 20 clockwise in FIG. 2. As a result, rotor ring 2
0 rotates smoothly and slowly clockwise around the bearing 10a of the base member 1O, and in conjunction with the rotation of the rotor ring 20, the aperture blades 30 rotate counterclockwise to the base member 1.
By rotating around the pin 12 at 0, the optical path A is closed as shown in FIG.

Furthermore, when a current is passed through the drive winding 23 in the opposite direction to that described above,
The rotor ring 20 rotates counterclockwise, and the aperture blades 30
rotates clockwise, opening optical path A. In this way, the optical path A
By opening and closing, it is possible to mechanically always provide appropriate exposure to the image pickup tube of a camera such as a still camera or a video camera according to the brightness of the field.

When the power supply to the drive winding 23 is cut off with the optical path A open as shown in FIG.
Midway portion 2 of the feeder line portion 28 bent in a curve along the inner circumferential surface of the
Due to the elastic force of 8b, the rotor ring 20
is rotated clockwise, the aperture blades 30 are rotated counterclockwise, and the optical path A is automatically closed. This reliably blocks sunlight from entering the electric aperture device.
It is possible to automatically prevent burn-in of the imaging tube, etc. of the camera.

Incidentally, since the power supply line section 28 is disposed in an upright state along the inner circumferential surface of the base member 10, the light is blocked by the aperture blades 30 and does not have any adverse effect on the optical system. Further, the power supply line portion 28 passes through the optical path A and the base member 1
Since the drive winding 2 is not pulled out along the outer peripheral surface of the
This has the advantage that the wiring structure for feeding power to the rotor ring 3 is simplified and does not interfere with the rotation of the rotor ring 20.

In addition, by integrally molding the bearing portion 10a with a simple structure on the base member 10 and using the presser plate 40 as one piece,
The number of parts is greatly reduced, and the drawing device can be made smaller and lighter.

Furthermore, since an inexpensive drive winding 23 wound with several hundred turns is used instead of an expensive printed coil, the rotor ring 20 can be rotated with low voltage and low current.
It consumes less power and is economically superior.

In this embodiment, the ferrite magnet 11 is embedded in the plastic base member IO containing glass fiber, but the entire base member may be made of a plastic magnet to reduce costs. Moreover, although the presser plate 40 is made magnetic, it may be made of a non-magnetic metal such as aluminum to further reduce the weight.

[Effects of the Invention] As described above, according to the present invention, the rotor ring provided with the winding and the aperture blade can be rotated between the disc-shaped base member which serves as the bearing part and the presser plate. By adopting a simple structure with clamping support, the number of parts can be reduced, making it possible to further reduce the size and weight of the entire electric diaphragm device. In addition, since the winding is used, the rotor ring can be rotated smoothly with low voltage and low current, and the maintenance cost is low and it is economically superior. Furthermore, by pulling out the flexible board that supplies power to the windings along the inner circumferential surface of the base member in the optical path, the structure of the power supply wiring is simplified, and the optical path is open to the windings. When the power supply is turned off, the elastic force of the flexible substrate allows the aperture blades to rotate and automatically close the optical path, thereby preventing burn-in of the camera's image pickup tube, etc.

[Brief explanation of drawings]

1 to 7 show embodiments of the present invention. FIG. 1 is an exploded perspective view of the electric throttle device, FIG. 2 is a front view of the same, and FIG. Fig. 4 is a sectional view taken along line IV-■ in Fig. 2, Fig. 5 is a front view of the closed electric diaphragm, and Fig. 6 is a perspective view of the a-talling turned over. , FIG. 7 is a block diagram of a drive circuit, and FIG. 8 is an exploded perspective view of a conventional electric diaphragm device. ! ...Electric diaphragm device, lO...Base member, lea
... bearing part, 11 ... ferrite magnet, 20
...Rotor ring, 23...Drive winding, 24...
Brake winding, 28... supply IT line part (flexible board)
, 30... Aperture blade, 40... Presser plate, A.
...light path. Figure 2 Figure 70 Middle Go ■ Line cross-sectional opening Figure 3 Figure 2 m Middle To Patent Application No. 204976 2, name of the invention Electric wringer device 3, relationship with the person making the amendment case Applicant (21g) Sony Corporation and above

Claims (1)

[Scope of Claims] A disc-shaped base member having at least one side surface formed of a magnet and having a bearing portion on the inner peripheral edge of the one side surface, and a plurality of windings on the side surface facing the magnet. Equipped with
These windings are pulled out along the inner peripheral surface side of the base member in the optical path and a thin plate annular non-magnetic rotor ring rotatably supported on the bearing part with a predetermined clearance from the magnet. a flexible substrate that supplies power to each of the windings; a proximal end is rotatably supported by a pin on the outer peripheral edge of one side of the base member, and a distal end side is slidable on the other side of the rotor ring; A plurality of aperture blades are movably stacked and arranged to open and close an optical path in conjunction with the rotation of the rotor ring, and the rotor ring is fastened and fixed to one side of the base member at a predetermined interval. An electric diaphragm device comprising: a thin annular holding plate that rotatably clamps and supports the diaphragm blades and the diaphragm blades.