JP2625629B2 - Light control device - Google Patents

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 a camera or the like, and more particularly to a light amount control device suitable for a video camera which is excellent in productivity and whose operation is ensured.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional light quantity control device. In the figure, 1 is a drawn ground plate, 2 is a yoke, 3A,
3B is a coil part, 4 is a flexible printed wiring board, 5
Is a Hall element, 6 is an insulating tape, 7 is a magnet, 8 is a drive arm, 10 and 11 are aperture blades, 12 is an ND filter, 13 is an aperture cover, 14 is a cap, and 15 is a shaft.

[0003] The assembly of the light quantity control device composed of the above members is generally performed as follows. That is,
The upper part of the shaft 15 to which the magnet 7 is fixed is inserted into the upper bearing 1a provided on the squeezed base plate 1, and the drive arm 3 is press-fitted or bonded to the upper end of the shaft. Then, a return spring 9 is attached to the drive arm 8, and the aperture blades 10 and 11 are attached to the drive arm 8.

In the lower part of the base plate, coils 3A, 3B, insulating tape 6, yoke 2
And the lower end of the shaft 15 is inserted through the lower bearing 14 a provided on the cap 14, and the cap 14 is fixed to the squeezed base plate 1 with screws 16.

[0005]

The conventional example has a structure in which the assembly as described above with reference to FIG. 2 is performed. Therefore, there were the following disadvantages.

(1) Since various parts are assembled from above and below the drawing base plate 1, it is difficult to automate the production. (2) A member constituting the bearing, that is, a cap is separately required.
(3) Since one bearing is free with respect to the other bearing, a tilt of the shaft occurs, operation becomes inaccurate, and shaft loss occurs. (4) The drive arm and the shaft must be formed as separate members. The cost of parts is high and the number of assembling man-hours is increased. (5) Supports and screws for fixing the meter section are required. (6) The yoke of the outer peripheral member of the meter section is illuminated by a lens or the like. Is reflected and a problem such as a ghost occurs. An object of the present invention is to solve the above problems.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a light amount control device for controlling a passing light amount by driving a diaphragm blade housed between a diaphragm base plate and a diaphragm cover by a driving arm rotated by a servomotor. In the apparatus, a rotation axis of the servomotor is formed on a drive arm, and the rotation axis is held between a first bearing formed on the aperture base plate and a second bearing formed on the aperture cover. By doing so, the number of parts and the number of assembling steps can be reduced, the size and weight can be reduced, and the operating characteristics can be improved.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing which best illustrates the features of the present invention. In the figure, reference numeral 1 denotes a drawn ground plate, 1a denotes a lower bearing as a first bearing, 1b denotes a relief hole for terminal pins of coils 3A and 3B described later, 1c denotes a positioning hole, and 1d denotes a coil 3
A, a hook for positioning or fixing 3B, 1e is a guide or positioning pin, 1f is a dowel, 1g, 1h,
1j, 1k is a guide pin, 1i is a hook claw, 1l is a hole,
1m is the aperture diameter, 1n is the recess for storing the aperture blades, 1p
Is a recess that houses the servomotor or yoke,
These elements 1 a to 1 p are provided on the drawn ground plate 1. The drawn ground plate 1 and the drawn cover 13 are preferably made of anodized aluminum, plastic reinforced with carbon fiber, or the like. 2 is a yoke having a concave portion 2a, 3 is 3A, 3B is a coil, 3Aa, 3Ab, 3B
Reference numerals a and 3Bb are provided on the coils 3A and 3B, respectively, and projections that fit into the positioning holes 1c of the drawing ground plate, 4 is a flexible printed wiring board, 5 is a hall element, 6 is an insulating tape, and 7 is a magnet having a hole 7a. It is. Reference numeral 8 denotes an arm 8-1, a shaft 8 serving as a rotation axis of a servomotor.
A drive arm with a shaft comprising:
a, a shaft portion 8b press-fit into the hole 7a of the magnet 7, a shaft portion 8c for winding the return spring 9, a flange portion 8d for pressing the return spring 9, and an upper bearing 13a to be described later. Shaft portion 8e, driving pin 8f,
8g and a locking pin 8h. 9 is a return spring, 1
Reference numerals 0 and 11 are aperture blades, and the blade 10 is a driving slot 10.
a, and guide slots 10b and 10c, and similarly, the blade 11 includes a drive slot 11a and guide slots 11b and 11b.
c. Reference numeral 12 denotes an ND filter. An aperture cover 13 is an upper bearing 13a as a second bearing.
A convex portion 13b for protecting the shaft portion, holes 13c provided at four locations so as to be hooked by the claws 1i, and positioning holes 13
d, aperture diameter 13e.

A light quantity control device according to one embodiment of the present invention
It is composed of the above-described members, and these members are assembled as follows.

The fixed portion 8b of the drive arm 8 around which the return spring 9 is wound is fixed to the hole 7a of the magnet 7 by press-fitting or bonding, the magnet is sandwiched between the coils 3A and 3B, and the Hall element 5 is soldered or the like. The fixed flexible printed wiring board 4 is bonded to one of the coils 3A or 3B with an adhesive or a double-sided tape, and is fixed with an insulating tape 6 so that no gap is formed between the bobbins. In this case, the outer diameter of the tape is such that there is no gap between the tape and the inner diameter of the yoke 2. Next, the yoke 2 is inserted into the recess of the drawing base plate, and the claw 1d of the drawing base plate 1 is
And fixedly positioned. In this case, the bearing 1a has a mortar shape, and guides the shaft tip smoothly to the bearing 1a. Further, as described above, the servomotor is formed mainly by the yoke, the coil, and the magnet.

The flexible printed wiring board 4 has a hole 1 l
Each of the holes 1c is provided with a corresponding one of the projections 3 of the coils 3A and 3B.
Aa and 3Ba, 3Ab and 3Bb are engaged to position the coil. The dowel 1f engages with the hole 2a of the yoke 2 for positioning. As described above, the meter section is drawn with the squeezed ground plate 1
Fixed to Next, one end of the return spring 9 is locked to a locking pin 8h of the drive arm 8 and the other end is locked to a locking portion (not shown) of the squeezed base plate 1, so that the drive arm 8 is in an auto-closed state. You will take a posture. Next, the guide pins 1g, 1h, 1j, and 1k of the aperture base plate 1 are inserted into the guide elongated holes 10b, 10c, 11b, and 11c of the aperture blade 10 and the aperture blade 11 to which the ND filter is bonded, respectively. Slots 10a, 11 for driving the blades 10, 11
a, insert the drive pins 8f and 8g of the drive arm 8 into
Each of the aperture blades 10 and 11 is housed in a recess of the aperture base plate 1.

Finally, the fitting shaft portion 8e of the drive arm 8 is fitted to the bearing 13a of the diaphragm cover 13, and
Insert the pin 1e of the drawn ground plate 1 into the hole 13d
The hook c is hook-engaged with the hook claw 1i, and the aperture base plate 1 and the aperture cover 13 are fixed to each other. In this case, the distal end of the shaft portion 8e is largely chamfered or rounded to facilitate insertion, and is protected by the convex portion 13b.

The embodiment of the present invention can be constructed and assembled as described above, and it is possible to assemble by a throw-in method from above with reference to the drawing ground plate, thereby enabling consistent automatic assembling. In addition, the shaft and the drive arm can be integrated, and the cap that supports the shaft of the drive arm can be eliminated and the fixing screw for the cap can be eliminated, reducing the number of parts, reducing manufacturing costs, and reducing weight and space. Becomes possible. Furthermore, by completely covering the yoke of the servomotor with the diaphragm base plate made of an anti-reflection color (material), it is possible to prevent optical image disturbance such as ghost and flare. Further, by positioning the members constituting the bearings, the centers of the upper and lower bearings are easily set, so that the shaft loss can be reduced, and the operating performance can be stabilized and improved.

[0014]

As described above, according to the present invention, the diaphragm blade housed between the diaphragm base plate and the diaphragm cover is driven by the drive arm rotated by the servomotor,
In the light amount control device for controlling the amount of transmitted light, a rotation axis of the servomotor is formed on a drive arm, and the rotation axis is formed on a first bearing formed on the diaphragm base plate and a second bearing formed on the diaphragm cover. By being sandwiched between the bearings, the light amount control device can be reduced in size and weight, and the number of parts and the number of assembly steps can be reduced, so that productivity is improved. Further, since the position accuracy of the rotary shaft of the servomotor is also improved, it is possible to provide a light quantity control device with low shaft loss and stable operation characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration of a light quantity control device embodying the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional light amount control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Drawing base plate, 1a ... Lower bearing (1st bearing), 2
... yoke, 3 ... coil, 4 ... flexible printed wiring board, 5 ... hall element, 6 insulating tape, 7 ... magnet,
8 ... drive arm, 8-2 ... shaft part (rotation axis), 9 ...
Return spring, 10, 11: diaphragm blade, 12: ND filter, 13: diaphragm cover, 13a: upper bearing (second bearing)

Claims (1)

(57) [Claims] 1. A squeezed base plate and a squeezed cover are accommodated between
Drive blades that rotate the aperture blades
In a light amount control device that controls the amount of transmitted light by driving with a system, a rotation axis of the servomotor is formed on a drive arm.
A first bearing formed on the drawn ground plate;
And a second bearing formed on the aperture cover.
A light amount control device characterized in that the light amount control device is sandwiched between the light amount control devices.