JP3189382B2 - ND filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ND filter for adjusting the brightness of a recorded image of a video camera or the like, and more particularly to a lock for locking the ND filter at a rotational position by a motor drive. It concerns the mechanism.

[0002]

2. Description of the Related Art Generally, the brightness of an image recorded by a video camera is adjusted by an iris. However, in the case of an iris, if the aperture is excessively reduced, the resolution of an image is reduced. Therefore, conventionally, an ND filter is attached to the iris to solve the above-described optical problem at the time of a small aperture of the iris.

[0003]

However, the above-described method has problems that the blurred image is poor and the image resolution is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to adjust the brightness of an image by a motor drive using a filter without deteriorating the image blur and reducing the resolution. It is an object of the present invention to obtain an ND filter provided with a mechanism capable of securely locking the rotational position of the filter.

[0005]

In order to achieve the above-mentioned object, an ND filter according to the present invention is provided for controlling the brightness of an image.
Frame holding filter for adjustment and iris
A fulcrum that is the center of rotation of the frame so that it can be moved in and out
Axis and the center line connecting the center of the filter from the fulcrum axis
Slotted hole formed parallel to one side of the frame
Guide hole and the outer periphery of the disc supported on the output shaft of the motor
Operation that is biased toward the
It is composed of a work pin.

[0006]

In the ND filter according to the present invention having the above-described structure, when the disk is rotated through the output shaft by driving the motor, the operation pin engaged with the guide hole of the filter is rotated. The filter rotates about a fulcrum axis. When the filter reaches the top dead center and slightly exceeds the top dead center, the motor stops. At this point, the filter attempts to return due to its own weight, but the operation pin hits the end of the guide hole, so that the so-called guide hole forms a difficult angle with the operation pin, and the filter is locked.

Also, when the filter is pivoted downward, when the filter slightly exceeds the bottom dead center, the operation pin abuts on the end of the guide hole due to the weight of the filter itself as described above. The filter is locked due to the difficulty of the operation pin.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an ND filter according to the present embodiment and its peripheral mechanism in a video camera, and FIGS. 2 and 3 are front views of respective operations showing how the ND filter is inserted into and removed from an iris.

In FIG. 1, reference numeral 1 denotes a pair of upper and lower irises as an aperture mechanism of a video camera, and an ND filter (hereinafter simply referred to as a filter) 2 according to the present invention is disposed in front of the iris 1. The filter 2 is held on the large-diameter portion 3a side of a substantially raindrop-shaped frame 3, and the small-diameter portion 3b of the frame 3 is rotatably supported by a fixing member of a camera body (not shown) around a fulcrum shaft 4 as a rotation center. The iris 1 can be put in and out of the iris 1 described above. An elongated guide hole 5 substantially parallel to the center line L is formed in an upper portion of the frame 3 with respect to the center line L of the frame 3.

Reference numeral 6 denotes a drive mechanism for operating the filter 2 with respect to the iris 1 by using a motor drive. The drive mechanism 6 includes a motor 7 and the motor 7
A gear section 8 for reducing the rotational torque of the gear section, a rotating disk 10 provided on a motor output shaft 9 of the gear section 8, and the rotating disk 1
And an operation pin 11 protruding to be biased to the outer peripheral portion of the O.D. The operation pin 11 is slidably engaged with the guide hole 5 formed in the frame 3 of the filter 2 described above.

That is, the gear section 8 is driven by the driving of the motor 7.
The rotating disk 10 rotates at a low speed via the
The frame 3 can be rotated about the fulcrum shaft 4 while the operation pin 11 protruding from the guide hole 5 slides in the long hole range of the guide hole 5.

FIG. 2 shows that the filter 2 is an iris 1
FIG. 3 shows a front view of a locked state removed from the optical axis of the iris 1, and FIG. 3 shows a locked state in which the filter 2 is inserted on the optical axis of the iris 1 .
The operation in the lock state will be described.

In the locked state shown in FIG. 2 in which the filter 2 is removed from the optical axis of the iris 1, as can be understood from FIG. 2, the position of the operation pin 11 is located closer to the fulcrum shaft 4 of the frame 3 than the motor output shaft 9. Thereby, the operation pin 11 abuts on the end of the guide hole 11 and an effect of locking the filter 2 at its rotational position can be obtained. This will be described in more detail. The position of the operation pin 11 in a state where the frame 3 rotates outside the optical axis and the frame 3 slightly exceeds the top dead center is a position indicated by a virtual line. , The drive of the motor 7 is stopped, but the operation pin 11 is rotated from the position of the imaginary line to the position of the solid line by the rotating action of returning the frame 3 by its own weight, and the end 5a of the guide hole 5 is formed.
, The frame 3 is locked. That is, the operating pin 11 has a biting angle with respect to the guide hole 5 and can be locked by these frictional actions.

On the other hand, in the state shown in FIG. 3 in which the filter 2 is inserted on the optical axis of the iris 1, the position of the operation pin 11 is located on the fulcrum shaft 4 side of the frame 3 with respect to the motor output shaft 9 in the same manner as described above. The position of the operation pin 11 in a state where the frame 3 is inserted over the optical axis and the frame 3 slightly exceeds the bottom dead center is a position indicated by a virtual line,
At this point, the drive of the motor 7 is stopped, but the operation pin 11 is rotated from the position of the imaginary line to the position of the solid line by the rotating action of returning the frame 3 by its own weight, and the frame 3 is moved to the end 5 a of the guide hole 5. When hit, the frame 3 is locked. That is, the operating pin 11 has a biting angle with respect to the guide hole 5 and can be locked by these frictional actions.

As described above, in the ND filter according to the present invention, the filter 2 can be moved in and out of the iris 1 by a motor drive, so that the brightness of the image can be reduced without deteriorating the image blur and the resolution as in the prior art. There is an advantage that the height can be easily adjusted. In addition, the rotational operation position of the filter 2 with respect to the iris 1 can be accurately locked without being displaced.

The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, the locking means of the filter 1 is not limited to that of the embodiment, and the operation pin 11 for rotating the filter 1 at each rotation position is locked by the action force that causes the filter 3 to form a hard angle into the frame 3. Other configurations may be used as long as they are performed. Also, it is preferable that the filter be put in and taken out, for example, during a rec pause, not during video recording.

[0017]

As described above, the ND in the present invention is
Since the filter allows the filter to be moved in and out of the iris by a motor drive, there is an effect that the brightness of the image can be easily adjusted without reducing the blurring or the resolution of the image as in the related art.

A filter is provided for the iris.
When the top dead center and bottom dead center in the insertion position are exceeded
And the operation pin moves to the guide hole due to the weight of the frame.
Since bite angle has to be locked to occur, can be stopped accurately without filter is Oite positional deviation out position.

[Brief description of the drawings]

FIG. 1 is a perspective view of a filter and a peripheral mechanism of the filter in this example.

FIG. 2 is a front view of a state in which a filter has been removed from an iris.

FIG. 3 is a front view of a state where a filter is inserted into an iris.

[Explanation of symbols]

 Reference Signs List 1 iris 2 filter 3 frame 4 fulcrum shaft 5 guide hole 7 motor 8 gear section 9 motor output shaft 10 rotating disk 11 operating pin

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-68325 (JP, A) JP-A-61-11731 (JP, A) JP-A-2-123335 (JP, A) JP-A-62 191837 (JP, A) JP-A-62-139536 (JP, A) JP-A-4-31130 (JP, U) JP-A-1-79031 (JP, U) JP-A-58-5022 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 11/00 H04N 5/235

Claims (2)

(57) [Claims] 1. A filter for adjusting brightness of an image.
The held frame and the filter are placed in front of the iris optical axis,
Turn the frame so that it can be taken in and out of the iris.
A fulcrum axis serving as a moving center, and a center line connecting the fulcrum axis to the center of the filter.
It is formed almost parallel to one side of the frame.
A long hole-shaped guide hole and a protruding part are provided on the outer periphery of the disk supported on the output shaft of the motor.
Operating pins that are engaged with the guide holes
At the position where the filter is moved in and out of the iris.
Above the top dead center and bottom dead center.
The operation pin is positioned at the end of the guide hole due to the weight of the arm.
The cut-off angle hits the part and the filter
An ND filter characterized in that the ND filter is locked at the insertion position . 2. The filter according to claim 1, wherein the top dead center and the bottom dead center are turned off.
The ND filter according to claim 1, wherein the position of the operation pin is set closer to the fulcrum shaft side than the output shaft of the motor at the time of overturn .