JPH07319005A - Light control device - Google Patents

Abstract

PURPOSE:To provide a quantity-of-light adjuster which is excellent in assembly property and can materialize the highly accurate positioning between a light-of- quantity adjuster and a driver by attaching a plurality of quantity-of-light adjusters to a common attaching member. CONSTITUTION:A lens retaining member 3 is provided with a stopper 3e for a stopping vane 14 and a stopper 3f for a stopping vane 15, and the stopping vane 14 is positioned in the position where the tip of the vane bumps against the vane stopper 3e of the lens retaining member 3. Moreover, the stopping vane 15 is positioned in the position where it bumps against the vane stopper 3f. Next, the claw 18d of a driver 18 abuts on the engaging part of the lens retaining member 3, and after the claw 18d is charged, each claw engages with the engaging part of the lens retaining member 3, and the driver 18 and the lens retaining member 3 are fixed. Hereby, a plurality of vanes can be positioned to the attaching member by means of a first restriction means, and a driving power transmitting member can be positioned by a second restricting means, so the highly accurate positioning of the latter to the former becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light quantity adjusting device used in a video camera or the like, and more particularly to a support structure for a light quantity adjusting member such as a diaphragm blade and a mounting structure for a driving portion for driving the light quantity adjusting member. It is a thing.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Utility Model Laid-Open No. 2-87222, a light quantity adjusting device used in a video camera or the like has a plurality of diaphragm blades for changing the area of the aperture diameter and a plurality of these diaphragms. A base plate having guide means for restricting the movement of the diaphragm blade so that the blade moves only in a predetermined direction, a blade pressing member for preventing the diaphragm blade from falling off the guide means, and a diaphragm blade drive attached to the base plate. And a drive unit for these components, and these elements are configured as a diaphragm unit. The assembly procedure is that the drive unit is installed in the main plate and then the blades are installed in the main plate,
The last blade holding plate is attached to the main plate.

There is also a conventional technique for reducing the size of a lens barrel as disclosed in Japanese Patent Laid-Open No. 4-310905. This is one in which the base plate described above is configured as a part of a lens barrel.

The drive unit has a drive lever attached to the end of the rotary shaft of, for example, a magnet rotor magnetized in two poles, and a drive pin implanted at the tip of the arm of the drive lever is used as a drive hole for the diaphragm blade. And is wound around an exciting coil around a yoke having magnetic poles arranged to face the outer circumference of the magnet rotor. In the drive unit having such a configuration, the magnet rotor returns to a predetermined position by the action of the detent torque when the exciting coil is de-energized, and, for example, the detent torque moves the diaphragm blades in the closing direction. The position of the diaphragm blade is determined by detecting the rotation of the magnet rotor by the Hall element provided in the drive unit. It has also been proposed to cancel the detent torque described above and move the diaphragm blade in the closing direction by a spring.

[0005]

However, in the conventional light quantity adjusting device, it is necessary to previously install the driving unit in the base plate and then to install the diaphragm blades in the base plate, so that the following problems are pointed out. There is.

(1) Since the diaphragm driving unit is provided with mounting components such as Hall elements, it is difficult to adjust the position of the Hall element with respect to the position of the diaphragm blade when the driving unit is first assembled to the base plate.

(2) Since it is necessary to position and install the diaphragm blades at two points, assembly workability is poor.

(3) In the unitized light quantity adjusting device, the rotation range of the arm of the drive unit is determined by the stopper provided on the base plate, which is the opening diameter or the minimum diaphragm diameter, which is the limit value of the diameter of the diaphragm blade. However, there is a drawback in that the accuracy of the light quantity at the time of opening and the light quantity at the time of the minimum aperture are deteriorated due to the influence of the assembly accuracy of the light quantity adjusting device and the lens barrel.

An object of the present invention is to solve the conventional problems described above, and to provide a light quantity adjusting device which is easy to assemble and which can realize highly accurate positioning between the light quantity adjusting member and the driving portion.

[0010]

A light quantity adjusting device according to claim 1 for achieving the object of the present invention is a plurality of light amount adjusting devices which are movably mounted on a mounting member so as to change an area of an opening diameter. Light amount adjusting means and driving means which is unitized and is attached to the mounting member for transmitting the driving force to the plurality of light amount adjusting means via the driving force transmitting member. The present invention is characterized in that a first regulating means for regulating the moving positions of the plurality of light amount adjusting means and a second regulating means for regulating the moving range of the driving force transmitting member are provided.

In this structure, a plurality of light quantity adjusting means, for example, the diaphragm blades and the driving means can be mounted on a common mounting member, for example, a lens holding member, and the first restricting means for the mounting member. Thus, the plurality of diaphragm blades can be positioned, and the driving force transmission member can be positioned by the second restricting means, so that the driving force transmission member can be accurately positioned with respect to the diaphragm blade.

A light quantity adjusting device according to a second aspect is
The fitting portion between the position where the driving force transmitting member is restricted by the second restricting means provided on the mounting member and the specific position where the plurality of light amount adjusting means are positioned by the balance of their own weights are substantially the same. It is characterized by being the same.

With this structure, when the lens barrel or the like to which the light quantity adjusting device or the like is attached is rotated by a predetermined angle, the connection with the driving force transmitting member becomes possible, and when the driving means is attached, the driving force transmitting member is attached. Is naturally connected to the light quantity adjusting means.

According to a third aspect of the present invention, there is provided the light amount adjusting device according to the first or second aspect, wherein the plurality of light amount adjusting means have portions which overlap each other even in the fully opened state.

With this structure, when the light amount adjusting means is moved from the fully open position to the closing direction, they are prevented from engaging with each other and interfering with each other, and the light amount adjusting means such as the diaphragm blades cannot be moved to the closing side. It

[0016]

FIG. 2 is an exploded perspective view showing an embodiment of a light amount adjusting device according to the present invention, and FIG. 1 is an exploded perspective view in which the light amount adjusting device of FIG. 2 is applied to a video camera lens. 3 shows a front view of the light quantity adjusting device of FIG.

In FIG. 1, 1 is a first holding member for holding the first lens group, 2 is a second lens holding member for holding the second lens group, and 3 is a third holding member for holding the third lens group. A lens holding member 4 is a fourth lens holding member that holds a fourth lens group, the first and third lens groups are fixed lens groups, and the second lens group is a moving lens group that performs a zooming action. The fourth lens group is a moving lens group that performs a focusing action.

The second lens holding member 2 is slid in the optical axis direction by the first guide bars 5 and 6 supported at one end by the first lens holding member 1 and at the other end by the third lens holding member 3. It is movably held.

The rack member 7 supported by the second lens holding member 2 meshes with the screw screw shaft 8a of the arc-shaped magnification changing motor 8 fixed to the third lens holding member 3 to change the magnification. The rotation of the screw shaft 8a of the motor moves the second lens holding member 2 in the optical axis direction. Here, the tip of the screw screw shaft 8a is pivotally supported by a bearing portion (not shown) provided in the first lens holding member 1.

The fourth lens holding member 4 has a second guide bar 10, one end of which is supported by the third lens holding member 3 and the other end of which is supported by a rear fixed lens barrel 9 having an image sensor mounting portion 9a.
It is held by 11 so as to be movable in the optical axis direction.

The rack member 12 supported by the fourth lens holding member 4 meshes with a screw screw shaft 13a of an arc-shaped focusing motor 13 fixed to the rear fixed lens barrel 9, and the rack motor 12 of the focusing motor 13 is engaged. The rotation moves the fourth lens holding member 4 in the optical axis direction. Similar to the screw screw shaft 8a of the zoom motor 8 described above, the tip of the screw screw shaft 13a is pivotally supported by a bearing portion (not shown) provided in the rear barrel 9.

The moving lens groups 2 and 4 are formed with flat plate-shaped projections 2a and 4b, respectively, and the infrared sensor 1
The positions of the respective movable lens groups are detected by 9 and 20. These protrusions 2a and 4b are the infrared sensor 1
This is to prevent outside light from entering into 9 and 20, and this may be such that the first holding member 1 is integrally provided with rib-shaped projections.

Reference numerals 14 and 15 denote diaphragm blades, which are diaphragm members and are formed in a substantially C-shape in a plane.
The D filter 16 is provided in the opening. The pair of diaphragm blades 14 and 15 are formed in a bilaterally symmetrical shape, and are sandwiched between the blade pressing plate 17 and the third lens holding member, and the driving arm 1 of the arc-shaped diaphragm driving unit 18 is provided.
By rotating 8a in the direction of the arrow, both diaphragm blades 14, 15
To drive the aperture blades 1 in the direction orthogonal to the optical axis.
It is possible to turn the light beams 4 and 15 to narrow the light beam.

FIG. 2 is a perspective view of the main part of the diaphragm section. In the exterior case of the unitized drive section 18, the rotation range of the rotor is restricted to a range wider than that determined by the optical conditions of the lens. A drive arm opening also serving as a stopper is provided, and the drive arm 18a penetrates through the opening to transmit the power generated in the drive unit to the outside.

The drive portion 18 is provided with spring means for urging the drive arm in a predetermined rotation direction, for example, in a closing direction. When the drive arm 18a is not energized, the drive arm 18a moves in a predetermined direction of the stopper. Hitting

The lens holding member 3 is provided with an opening 3a which also serves as a stopper for restricting the range of rotation of the drive arm 18a of the drive unit 18 to a range required for optical performance. When the drive unit 18 is assembled to the lens holding member 3,
Since the stopper range of the opening 3a provided in the lens holding member 3 is narrower than the opening for the drive arm provided in the drive unit 18, the drive arm 18a is set in the predetermined direction of the opening 3a of the lens holding member 3. It will hit the end.

On one surface side of the lens holding member 3, a rotation support shaft 3b on which the shaft holes 14b and 15b of the diaphragm blades 14 and 15 are respectively supported, and a guide rail 3c with which the diaphragm blade 14 is in contact.
There are provided a diaphragm blade stopper 3e with which the rotating tip of the diaphragm blade 14 abuts, an aperture blade stopper 3f with which the rotating tip of the diaphragm blade 15 abuts, and a blade holding plate fixing claw 3d.

The holding plate 17 is fixed by being snap-fitted and held by the claw portions 3d provided on the lens holding member 3 so as to maintain a predetermined clearance with the lens holding member 3, and the light of the diaphragm blades 14 and 15 is fixed. Axial position is restricted.

As described above, the lens holding member 3 is provided with the stopper 3e for the diaphragm blades 14 and the stopper 3f for the diaphragm blades 15, and with the diaphragm blades 14 and 15 and the holding plate 17 assembled, When the lens holding member 3 is rotated counterclockwise by 90 ° from the state shown in FIG. 2 so that the position where the drive unit 18 is attached comes to the upper side, the diaphragm blade 149 is centered on the shaft hole 14b which is a fulcrum by its own weight. The blade stopper 3 of the lens holding member 3 rotates when the blade tip is rotated.
It is positioned at the position hit by e. Similarly, the diaphragm blade 15 rotates by its own weight around the shaft hole 15b, which is a fulcrum, and the blade tip is positioned at a position where it comes into contact with the blade stopper 3f of the lens holding member 3. Here, the state where the tips of both diaphragm blades hit the blade stoppers 3e and 3f of the lens holding member 3 coincides with the substantially minimum diaphragm position for light amount adjustment. In a current video camera, the diaphragm is generally fully closed. Therefore, in the present embodiment, the diaphragm blade is in a state where the tip ends of both diaphragm blades 14 and 15 hit the blade stoppers 3e and 3f of the lens holding member 3. Is fully closed.

The guide rails 17a formed integrally with the holding plate 17 contact the diaphragm blades 15 so that both diaphragm blades can operate smoothly without contacting each other. In the fully open position, overlapping portions 14c and 15c shown by diagonal lines are formed on both diaphragm blades 14 and 15 to provide a guide overlap so that the rotating tip portions of both diaphragm blades do not interfere with each other. .

On the other hand, in the outer case of the driving portion 18, there are provided a first positioning pin 18b which fits into the first positioning hole 3g of the lens holding member 3 and a second positioning pin 18b of the lens holding member 3 as well.
Positioning pin 18c that fits into the positioning hole 3h
And a plurality of mounting hooks 18d having a spring property for engaging with the engaging portion of the lens holding member 3 are formed, and the lens holding member 3 is formed along the optical axis direction of the drive portion 18.
When pressed against, the first and second positioning pins 18b, 1
8c are fitted into the first and second positioning holes 3g and 3h, respectively, so that the drive unit 18 is positioned with respect to the lens holding member 3 in the direction orthogonal to the optical axis. The plurality of mounting hooks 18 d included therein are engaged with the engaging portions of the lens holding member, and the drive portion 18 is fixed to the lens holding member 3.

At this time, the drive arm 18a of the drive unit 18 is provided with the elongated holes 14 of the diaphragm blades 14 and 15 which overlap each other.
a, 15a. That is, when assembling the light quantity adjusting device according to the present embodiment, both aperture blades 14 and 15 and the holding plate 17 are assembled to the lens holding member 3 as described above, and rotated 90 ° counterclockwise from the state shown in the drawing. Let
When the diaphragm blades 14 and 15 are set to the fully closed position by their own weight and the driving unit 18 is assembled to the lens holding member 3 from the optical axis direction, first, the first and second positioning pins 18 of the driving unit 18
b and 18c are fitted into the first and second positioning holes of the lens holding member 3, and are urged by the spring means built in the drive unit 18 toward one end of the opening of the drive unit 18 which also serves as a stopper. The drive arm 18a is biased against one end of the opening 3a that also functions as a stopper of the lens holding member 3 against the biasing force, and then the tip of the drive arm 18a is moved toward the diaphragm blades 14 and 15 from each other. When the drive unit 18 is pushed in as it is, the drive arms 18a are aligned with the overlapping elongated holes 14a and 15a in the optical axis direction.
The tip end of the is inserted into and fitted into the elongated holes 14a and 15a.

Next, the claw portions 18d of the driving portion 18 contact the engaging portions of the lens holding member 3, and after the claw portions 18d are charged, the respective claw portions engage with the engaging portions of the lens holding member 3. The drive unit 18 and the lens holding member 3 are fixed.

Here, the stopper for determining the position of the drive arm 18a corresponding to the fully closed position of the diaphragm blade is effective because the stopper of the lens holding member 3 close to the diaphragm blade is effective. Even if the diaphragm blades are separated from each other in the optical axis direction, the arm pin and the diaphragm blades are surely fitted to each other and the minimum diaphragm position including a predetermined fully closed position is determined.

Further, the positioning pin and the lens holding member 3
, The drive arm and the diaphragm blade are fitted together, and then the mounting claw portion 18d is charged. Therefore, the clearance between the positioning pin and the positioning hole is relatively large,
The drive unit 1 is driven by the force that charges the mounting claw 18d.
Even when the relative positions of the lens holding member 8 and the lens holding member 3 are easily misaligned, the drive arm pin can securely assemble the diaphragm blade without damaging the diaphragm blade.

The third lens holding member 3 has a structure shown in FIG.
As shown in FIG. 3, since the diaphragm blades slide near the hole supporting the guide bar 6, a wall surface 3i is formed to prevent the oil applied to the guide bar 6 from bleeding.

Further, in the above-mentioned embodiment, the arc-shaped motor drive portion is used in order to make the entire lens barrel compact, but the invention is not limited to this.
The same effect can be obtained with a round actuator.

Further, the third part which constitutes the diaphragm unit
The lens holding member is also integrated in order to reduce the number of parts and space, and of course the lens holding portion and the diaphragm base plate portion may be provided separately.

[0039]

As described above, according to the first aspect of the invention, the plurality of light amount adjusting means, for example, the diaphragm blades and the driving means are mounted on a common mounting member such as a lens holding member. Since the plurality of diaphragm blades can be positioned with respect to this mounting member by the first restricting means, and the driving force transmitting member can be positioned by the second restricting means, the height of the driving force transmitting member with respect to the diaphragm blade can be increased. Accurate positioning is possible.

According to the second aspect of the invention, when the lens barrel or the like to which the light amount adjusting device is attached is rotated by a predetermined angle, the driving force transmitting member can be connected and the driving means is driven. When the is attached, the driving force transmission member is naturally connected to the light quantity adjusting means.

According to the third aspect of the invention, when the light amount adjusting means is moved from the fully open position to the closing direction, they are engaged with each other and interfere with each other, and the light amount adjusting means such as the diaphragm blades can be moved to the closing side. It is prevented from disappearing.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a state in which the light quantity adjusting device of FIG. 2 is assembled to a video lens.

FIG. 2 is an exploded perspective view showing a first embodiment of the light quantity adjusting device according to the present invention.

FIG. 3 is a front view of the light quantity adjusting device of FIG.

[Explanation of symbols]

 1 1st lens holding member 2 2nd lens holding member 3 3rd lens holding member 4 4th lens holding member 5, 6 guide bar 3e, 3f stopper 14, 15 diaphragm blade 17 blade holding plate

Claims (3)

[Claims] 1. A plurality of light amount adjusting means movably assembled to a mounting member so as to change an area of an opening diameter, and a driving force is transmitted to the plurality of light amount adjusting means via a driving force transmitting member. Drive unit attached to the mounting member as a unit, and the mounting member includes a first restricting unit for restricting movement positions of the plurality of light amount adjusting units, and the driving force transmitting member. A light amount adjusting device, comprising: a second restricting means for restricting a moving range. 2. The driving force transmitting member according to claim 1, wherein the driving force transmitting member is regulated by the second regulating means provided on the mounting member, and the specific position at which the plurality of light amount adjusting means are positioned by the balance of their own weight. The light quantity adjusting device, wherein the fitting portions are substantially the same. 3. The light amount adjusting device according to claim 1 or 2, wherein the plurality of light amount adjusting means have portions overlapping with each other even in a fully opened state.