JPH06273822A - Light quantity controller - Google Patents

Abstract

PURPOSE:To eliminate the need of replacing a driving part even in the case a lens barrel is replaced by separably integrating a substrate for assembling a magnet rotor and an electromagnet coil in a circular-arculate shape and a base plate for storing a diaphragm blade in the lens barrel into one body. CONSTITUTION:When the electromagnet coil 2 is energized through the flexible substrate 7, stators 3 and 4 are energized, and then, the magnet rotor 1 is rotated. When a current to the electromagnet coil 2 is controlled by a control part based on the output from Hall element 6 at this time, an angular position for stopping the magnet rotor 1 and a rotational speed which is required to reach the position are controlled. By rotating the magnet rotor 1, a driving force is transmitted to a diaphragm blade 10 by the pin 1a of the magnet rotor 1 through the oblong hole 10a of the diaphragm blade 10 so as to open and close the diaphragm blade 10. By pushing the stepped parts 8g and 8f of the substrate 8 after making the stepped parts abut on the hook pawls 9c and 9d installed integrally with the base plate 9 and having a proper amount of elasticity, the driving part unit (substrate) 8 is engaged with the base plate 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount control device for controlling the amount of light received in an optical device of a video camera.

[0002]

2. Description of the Related Art Conventionally, the drive unit of a light quantity control device (diaphragm device) incorporated in a video camera or the like is of a cylindrical galvanometer type. FIG. 8 is an exploded perspective view showing this type of diaphragm device. In FIG. 8, reference numeral 24 is a diaphragm mechanism section and a base of a galvanometer section which is a drive source of the diaphragm mechanism section, 37 is an electromagnetic coil, and 33 is an electromagnetic coil 37.
Is a bobbin for winding. 38 is a bobbin 3
3 is the same as that of 3, but the electromagnetic coil is a bobbin not wound, 36 is a magnet rotor, 34 is a Hall element, 31 is a yoke for stabilizing magnetic flux, 35 is a wiring board, 32 is an upper cover, 39 Is a screw.

FIG. 9 (b) is a diagram showing a schematic structure of the cylindrical electromagnetic circuit portion of FIG. The outermost diameter of the galvanometer portion is at least the outer diameter of the yoke 31 with respect to the basic diameter D of the magnet, which is about 2D. As shown in FIG. 9B, a dead space occurs in the light quantity control device of the type in which the magnet rotor 36 is driven by the electromagnetic coil 37 and the speed is controlled by the hall element 34. That is, although the ideal shape of the lens barrel used in a video camera or the like is a cylindrical shape, in the conventional galvanometer type, the galvanometer portion extends out of the lens barrel circle as shown in FIG. 9B. ing.

Further, as to assembly, as shown in FIG. 8, the magnet rotor 36 has bobbins 33 and 38 as main constituent elements. Then, the base 24 and the upper cover 32
Between the members 31, 33, 34, 35, 36, 37, 3
8 is incorporated and is integrated by screwing the upper cover 32 to the base 24 with the screw 39. Next, the lever 22 is assembled using the shaft 36a of the magnet rotor 36 and the hole 22a of the lever 22 by using a joining means such as press fitting or adhesion. Then, by assembling the spring 23, a shape that can function as a drive unit is completed. Above the drive unit, a wind turbine lever 20 and diaphragm blades 25, 26, 2 are further provided.
7. The cover 28 is assembled.

[0005]

However, the above-mentioned conventional example has the following drawbacks. (1) As the lens (camera) becomes smaller, even if the diaphragm mechanism is housed inside the lens cylinder, the drive unit extends out of the cylinder. (2) In the galvanometer type of which the speed is controlled by the hall element, the conventional braking coil is unnecessary and a space is left in the space, but it remains as a dead space. (3) Since the galvanometer unit, which is the drive unit, is integrated with the diaphragm mechanism unit, when the lens barrel changes,
The drive unit must also be changed.

In view of the above drawbacks, it is an object of the present invention to provide a light quantity control device which does not need to change the driving unit even if the lens barrel changes.

[0007]

The light amount control device of the present invention is a light amount control device for controlling the amount of passing light by opening and closing diaphragm blades, and is composed of a cylindrical permanent magnet, and is rotated around a cylindrical axis. A magnet rotor that opens and closes the diaphragm blades, a magnetic force detection element that detects the magnetic force generated by the magnet rotor, and an electromagnetic coil for setting the magnet rotor at a desired angular position based on the detection result of the magnetic force detection element. And a base for assembling at least the magnet rotor and the electromagnetic coil in an arc shape so as to be stored along the inner wall of the lens barrel, and a base that is separably integrated with the base and the diaphragm blade It has a main plate for storing in a cylinder.

Preferably, the base and the base plate are separably integrated by hook claws or screws, and the magnetic force detecting element is a Hall element.

[0009]

The magnet rotor, the magnetic force detecting element and the electromagnetic coil are mounted on the base so that the magnet rotor can be housed along the inner wall of the lens barrel. The base plate is housed in the lens barrel together with the diaphragm blades. In this state, the base and the ground plate are separably integrated and used. Even if the lens barrel changes
It is only necessary to change the base plate and diaphragm blades, and it is not necessary to change the base and the drive members such as a magnet rotor attached to the base.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. 1 is an exploded perspective view showing a first embodiment of the light quantity control device of the present invention, FIG. 2 is a view of the upper portion of the embodiment of FIG. 1 seen from below, FIG. 3 is a sectional view of a 5f portion of FIG. 4 is a cross-sectional view of the 5e portion of FIG. 1, FIG. 5 is a cross-sectional view of the magnet rotor of FIG. 1, and FIG. 6 is a diagram showing a drive relationship between the electromagnetic coil, the stator, and the magnet rotor of FIG.

In FIG. 1, reference numeral 1 is a magnet rotor in which a magnet, a shaft and a drive lever are integrated. The magnet rotor 1 is integrally formed in a lever shape by a method of insert molding a molding material such as a resin into a hollow cylindrical magnet. Reference numeral 2 is an electromagnetic coil, 3 is a stator for inducing an exciting force of the electromagnetic coil, and 4 is a stator which is separate from the stator 3 but serves as an integrated electromagnetic force induction with the stator 3 when assembled. The stators 3 and 4 are magnet rotors 1 at one end.
And the other ends are in contact with each other to form a magnetic path.

Reference numeral 5 is an upper cover provided with a bearing portion for rotatably supporting the magnet rotor 1, 6 is a Hall element,
Reference numeral 7 has a solder joint portion for solder-joining the solder joint portion of the Hall element 6 and the lead portion of the electromagnetic coil 2 to each other.
Flexible substrate for exchanging I / O (hereinafter FP
(Abbreviated as C), 8 is a drive unit base for assembling the members 1 to 5, 9 is a base plate which is a base of the entire light amount control device, and 10 is a diaphragm for controlling the amount of passing light. Feather,
Reference numeral 11 is a cover plate for confining the diaphragm blade 10 with the base plate 9. When the electromagnetic coil 2 is energized via the FPC 7, the stators 3 and 4 are excited and the magnet rotor 1 rotates. At this time, the current from the Hall element 6 to the electromagnetic coil 2 is controlled by the controller (not shown).
Is controlled, the angular position at which the magnet rotor 1 stops and the rotation speed up to that position are controlled. The rotation of the magnet rotor 1 causes the pin 1 of the magnet rotor 1 to rotate.
The driving force a is transmitted to the diaphragm blades through the elongated holes 10a of the diaphragm blades 10 to open and close the diaphragm blades 10.

The members 1 to 8 are constructed so that they can be unitized as a drive unit. First, the stator 4
Is dropped while fitting the holes 4a and 4b into the shafts 8a and 8b for positioning provided on the base 8 (FIG. 3, FIG.
(Fig. 4). Next, so that the shaft 8c of the base 8 can be slidably engaged,
The engaging hole 1c (FIGS. 1 and 5) provided in the magnet rotor 1 is engaged with the shaft 8c. Next, the stator 3 previously inserted into the rectangular hole 2a of the electromagnetic coil 2 is dropped into the positioning shaft portion 8d provided on the base 8 while fitting the hole 3d. By appropriately pushing the hook portions 5e, 5f integrally provided on the upper cover 5 into the step portions 8e, 8f provided on the base 8, the hook portions 5e, 5f are pressed against each other. Engage (FIGS. 3 and 4).
Here, the hook 5f also has an acting force in the direction of bringing the stator 3 into close contact with the stator 4. At this time, positioning shafts (shafts 5g and 5d in FIG. 2) provided on the rear side of the upper cover 5 corresponding to the holes 4a and 3d of the stator are simultaneously lightly press-fitted, and the shaft of the base 8 is also fitted. Portion 8i and hole 5 in upper cover 5
i is lightly press-fitted. At the same time, the shaft portion 1b of the magnet rotor 1 is slidably inserted into the bearing hole 5a of the upper cover 5. At the same time, the coil lead terminals 2b and 2c provided on the electromagnetic coil 2 are allowed to pass through the clearance holes 5b and 5c of the upper cover 5 with a clearance. Next, the FPC 7 on which the Hall element 6 is mounted in advance is fixed to the upper cover 5 using a fixing means such as an adhesive material. At this time, the terminals 2b and 2c penetrating the holes 5b and 5c and projecting from the upper cover 5 are F
The solder land holes 7b and 7c of the PC 7 are penetrated, and the hole 7
The solder land pattern provided around b and 7c and the terminals 2b and 2c are soldered to complete a drive unit. The drive unit is applied to hook claws 9c and 9d integrally provided on the base plate 9 and having appropriate elasticity, and is engaged by pushing in the stepped portions 8g and 8f of the base 8 to drive the base 8 (drive Part unit) and the main plate 9 are integrated.

Next, the operation of the arc-shaped galvanometer section will be described with reference to FIG. FIG. 6A shows a state in which the diaphragm blade 10 of the embodiment shown in FIG. 1 is held in the closed position. At this time, the electromagnetic coil 2 is not excited, and the pole position of the magnet rotor 1 and the stator 3,
From the positional relationship of the shape of No. 4, the magnet rotor 1 has a biasing force in the counterclockwise direction of the arrow due to its own magnetic force. At this time, the magnet rotor 1 is restrained by the base 8 and the stopper 8k (9e) of the base plate 9.

As shown in FIG. 6B, while energizing the electromagnetic coil 2 while applying servo by the output of the Hall element 6, the stator 3 is an N pole and the stator 4 is an S pole.
When magnetized to the pole, the magnet rotor 1 rotates clockwise. Then, it is suppressed by the stopper 8l (9f), and the diaphragm blade 10 becomes the maximum opening. As shown in FIG. 6C, when the amount of electricity supplied to the electromagnetic coil 2 is reduced while applying servo based on the output of the Hall element 6, the magnet rotor 1 rotates counterclockwise and the diaphragm blade 10 closes. , And returns to the state of FIG. Further, the light quantity control device of this embodiment can be housed in the lens barrel in an ideal shape as shown in FIG. 8A due to the arcuate shape.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the screw 1 is used instead of the base 8 and the base plate 9 shown in FIG.
The base 13 and the main plate 14 are fastened together by 5.

[0017]

As described above, according to the present invention, the diaphragm blade is opened and closed by the magnet rotor driven by the electromagnetic coil, and the base for assembling the magnet rotor and the electromagnetic coil in an arc shape and the diaphragm blade are provided. The following effects can be obtained by detachably integrating the base plate for storing in the lens barrel.

(1) The magnet rotor makes it possible to integrate the magnet, the shaft and the drive lever. That is, if the molding material used for ferrite magnets is used,
Instead of combining three parts made of different materials such as a shaft and a drive arm, it is possible to form the same material into an integral shape and configure it as one part. This enables downsizing of the diaphragm device and effective use of dead space.

(2) The arc-shaped shape can contribute to downsizing of the lens barrel of a video camera or the like.

(3) Since the integral molding is possible as described above, uniform and high accuracy is guaranteed, and problems such as performance deterioration and instability due to the positional deviation between the arm and Mg are solved.

(4) Since the base and the base plate can be separated, the drive unit assembled to the base can be unitized. That is,
Even if the lens barrel or the diaphragm mechanism is changed, the drive unit can be used in common and it has versatility.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a light quantity control device of the present invention.

FIG. 2 is a view from above of the upper part of the embodiment of FIG.

FIG. 3 is a sectional view taken along line 5f in FIG.

FIG. 4 is a sectional view taken along line 5e of FIG.

5 is a cross-sectional view of the magnet rotor 1 of FIG.

6 (a), (b) and (c) are diagrams showing a driving relationship among the electromagnetic coil 2, the stators 3, 4 and the magnet rotor 1 of FIG.

FIG. 7 is an exploded perspective view showing a second embodiment of the present invention.

FIG. 8 is an exploded perspective view of a conventional light amount control device.

9A and 9B are schematic diagrams comparing the space between the ideal shape and the shape of the conventional example.

[Explanation of symbols]

 1 Magnet Rotor 2 Electromagnetic Coil 3,4 Stator 5 Upper Cover 6 Hall Element 7 FPC 8,13 Drive Unit Base 9,14 Base Plate 10 Aperture Blade 11 Cover Plate 15 Screw

Claims (4)

[Claims] 1. A light quantity control device for opening and closing diaphragm blades to control the amount of light passing therethrough, comprising: a magnet rotor which is made of a cylindrical permanent magnet and opens and closes the diaphragm blades by rotating around a cylindrical axis. A magnetic force detection element that detects the magnetic force generated by the rotor, an electromagnetic coil that sets the magnet rotor at a desired angular position based on the detection result of the magnetic force detection element, and at least the magnet rotor and the electromagnetic coil that are lens mirrors. It has a base for assembling in an arc shape so that it can be stored along the inner wall of the cylinder, and a base plate that is separably integrated with the base and that stores the diaphragm blade in the lens barrel. A characteristic light amount control device. 2. The light amount control device according to claim 1, wherein the base and the base plate are separably integrated by hook claws. 3. The light quantity control device according to claim 1, wherein the base and the base plate are separably integrated by a screw. 4. The light quantity control device according to claim 1, wherein the magnetic force detection element is a Hall element.