JP3353138B2 - Aperture control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aperture control device provided on a lens of a CCTV camera.

[0002]

2. Description of the Related Art Conventionally, this type of aperture control device has
There is known an apparatus in which the aperture of a diaphragm is adjusted by raising and lowering a plurality of diaphragm blades. In this configuration, each aperture blade is connected by a link mechanism, and the link mechanism is connected to a drive shaft of a servo meter. The drive shaft is provided with a spring that urges the diaphragm blade in a direction to close the opening. The link mechanism rotates when the servo meter is energized, and stops at a position where the electromagnetic force generated by the energization and the spring force are balanced. That is, the opening degree of the throttle is determined by the current value supplied to the servo meter.

[0003]

The diaphragm blades are supported by a guide mechanism so as to be displaced linearly, for example, but the guide mechanism has a mechanical error or clearance. Therefore, when the servo meter is energized, that is, when the aperture blade is stationary with the opening being opened by a predetermined amount, the aperture blade may move due to, for example, a change in the attitude of the camera. When the diaphragm blade moves in this manner, an error occurs in the degree of opening of the diaphragm. Further, if there is a clearance in the guide mechanism, a time delay occurs in adjusting the opening degree of the diaphragm, and hysteresis occurs in the opening and closing operation of the diaphragm.

An object of the present invention is to provide a diaphragm control device which prevents various problems due to mechanical errors of a guide mechanism, has high reliability, and can adjust the degree of opening of the diaphragm with high accuracy. The purpose is.

[0005]

An aperture control device according to the present invention comprises an aperture unit substrate having an opening formed therein and an aperture unit substrate supported by the aperture unit substrate in a reciprocating manner. First and second aperture blades whose degree can be adjusted;
And a first link mechanism for connecting the second aperture blade,
A driving source for reciprocating the first and second aperture blades by driving the first link mechanism;
A second link mechanism provided on the opposite side to the first link mechanism with the opening interposed therebetween, and a spring for urging the second link mechanism in a predetermined direction. It is characterized by:

[0006] The spring biases the second link mechanism in a direction in which the opening is closed or opened. The spring is preferably a coil spring provided around the rotation axis of the second link mechanism.

The first and second link mechanisms have, for example, first and second levers which are rotatable in a plane parallel to the aperture unit base material. These levers may be configured to always rotate in opposite directions, or may be configured to always rotate in the same direction.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a diaphragm control device according to a first embodiment of the present invention.

The aperture unit base member 11 is a rectangular plate member, and a circular opening 12 is formed substantially at the center. On the front side of the aperture unit base material 11, a blade holding plate 21 is provided in parallel with the aperture unit base material 11. The blade holding plate 21 is a plate member that is thinner than the aperture unit base material 11, and its outer shape is substantially the same as the aperture unit base material 11. Blade holding plate 2
1 also has a circular opening 22 formed therein. This opening 22
Has substantially the same size as the opening 12 of the aperture unit base material 11, and these openings 12, 22 are provided at positions corresponding to each other.

Aperture unit substrate 11 and blade holding plate 21
Between them, first and second aperture blades 31 and 41 are provided. The aperture blades 31 and 41 are the aperture unit base material 1
1 can be reciprocated freely, and its moving direction is shown in FIGS.
In the vertical direction. As shown in FIG. 3, first and second aperture holes 32 and 42 are formed in the aperture blades 31 and 41, respectively. The apertures 32, 42 are arc-shaped portions 32a, 42 each having an outer shape of a three-quarter circle.
a and linear portions 32b, 42b extending from the ends of the arc-shaped portions 32a, 42a. Therefore, when the arc-shaped portions 32a and 42a are completely overlapped with each other, a circular hole is formed. When the arc-shaped portions 32a and 42a are shifted, a substantially square hole is formed by the linear portions 32b and 42b (reference P in FIG. 5). Is formed.

The aperture holes 32 and 42 are provided with the aperture blades 3.
When they are in the inoperative position (the state shown in FIGS. 1 to 4), they do not overlap each other, so that the apertures 12, 22 are closed by the aperture blades 31, 41. On the other hand, when the diaphragm blades 31 and 41 move from the non-operation position (the state shown in FIG. 5), the diaphragm holes 32 and 42 overlap and the openings 12 and 22 are opened. That is, the first and second aperture blades 3
1, 41 can adjust the opening degree of the openings 12, 22 in cooperation with each other.

As shown in FIG. 3, the first diaphragm blades 31 are formed on both sides of the diaphragm hole 32 and extend vertically and first and second vertical slits 33 and 34, and a first vertical slit 33. A first horizontal slit 35 is provided near the upper end of the vertical slit 33 and extends in the horizontal direction. . Similarly, the second diaphragm blade 41 is provided near first and second vertical slits 43 and 44 extending vertically and near the upper end of the second vertical slit 44 and extends in the first horizontal direction. A slit 45 and a second horizontal slit 4 that is provided at a portion extending from the lower end of the first vertical slit 43 and extends in the horizontal direction.
6.

The aperture unit substrate 11 is provided with four guide pins 61, 62, 63, 64, which are fixed to holes formed in the blade holding plate 21. ing. In the first diaphragm blade 31, guide pins 61 and 62 are engaged with the first vertical slit 33, and guide pins 64 are engaged with the second vertical slit. Therefore, the first diaphragm blade 31 can move up and down along the first and second vertical slits 33 and 34. In the second diaphragm blade 41, the first vertical slit 43
Are engaged with the guide pins 62, and the second vertical slits 44 are engaged with the guide pins 63 and 64. Therefore, the second aperture blade 41 is provided with the first and second vertical slits 43, 4
4 can be moved up and down freely.

A servo meter 51 as a drive source is provided at the upper end on the back side of the aperture unit base material 11.
The drive shaft 52 of the servo meter 51 is
, And a first lever 53 is fixed to the end thereof. The first lever 53 is connected to the aperture unit base material 1.
It is rotatable in a plane parallel to 1. An electromagnetic coil is provided inside the servo meter 51, and the drive shaft 52 and the first lever 53 rotate by an angle corresponding to a current value supplied to the electromagnetic coil.

Drive pins 54 and 55 are fixed to both ends of the first lever 53. Slots 13, 14, 23, and 24 extending along an arc centered on the drive shaft 52 are formed in the aperture unit base material 11 and the blade holding plate 21, respectively. The long hole 13 of the aperture unit base material 11 and the long hole 23 of the blade holding plate 21 overlap each other. The first horizontal slit 35 formed in the first diaphragm blade 31 is located at the position of the slots 13 and 23, and the drive pin 54 is connected to the slot 1.
3 and 23 and the first horizontal slit 35. On the other hand, the first horizontal slit 45 formed in the second diaphragm blade 41 is located at the position of the long holes 14 and 24 and the driving pin 55
Penetrates the long holes 14, 24 and the first horizontal slit 45.

That is, the first lever 53 and the drive pin 5
4, 55, the first and second aperture blades 31, 4
1 is formed, and when the servo meter 51 is driven, the first lever 53 is rotationally displaced,
As a result, the first and second aperture blades 31, 41 move in the vertical direction.

A second lever 57 is rotatably provided at the lower end on the back surface side of the aperture unit base material 11 via a rotary shaft 56. The second lever 57 is rotatable in a plane parallel to the aperture unit base material 11. Drive pins 58, 59 are fixed to both ends of the second lever 57. A slot 1 extending along an arc centered on the rotation axis 56 is provided in the aperture unit base material 11 and the blade holding plate 21.
5, 16, 25, and 26 are formed respectively. The elongated hole 15 of the aperture unit base material 11 and the elongated hole 25 of the blade holding plate 21 overlap each other. The second horizontal slit 46 formed in the second diaphragm blade 41 is at the position of the long holes 15 and 25, and the drive pin 59 passes through the long holes 15 and 25 and the second horizontal slit 46. On the other hand, the first diaphragm blade 3
The second horizontal slit 36 formed in the slot 1
6, the drive pin 58 passes through the elongated holes 15, 25 and the second horizontal slit 36.

That is, the second lever 57 and the drive pin 5
8, 59, the first and second aperture blades 31, 4
A second link mechanism that connects the first link mechanism and the first link mechanism is provided across the openings 12 and 22.

A coil spring 71 is provided around the rotation shaft 56. One end of the coil spring 71 is connected to a fixing pin 72 provided on the aperture unit base material 11. The spring 71 moves the second link mechanism or lever 57 clockwise in FIGS. 1, 4 and 5, that is, the first and second aperture blades 31 and 41.
Are urged in a direction to close the openings 12 and 22. Therefore, when the servo meter 51 is not energized and is not operated, FIG.
As shown in FIG. 4 and FIG. 4, the first diaphragm blade 31 is at the raised position, the second diaphragm blade 41 is at the lowered position, and the openings 12 and 22 are closed.

On the other hand, when the servo meter 51 is energized, the first lever 53 rotates clockwise, whereby the first diaphragm blade 31 descends and the second diaphragm blade 41 rises. I do. That is, the second lever 57 rotates counterclockwise against the spring force of the spring 71,
And the movement of the second diaphragm blades 31 and 41 causes the opening 1 to move.
2, 22 are released. The aperture blades 31 and 41 stop at a position where the electromagnetic force generated in the servo meter 51 and the spring force generated in the spring 71 are balanced.

As described above, in the present embodiment, the first and second levers 53 and 57 are configured to always rotate in opposite directions.

As described above, in the present embodiment, the openings 12,
The first and second aperture blades 31 and 4 are attached to a second lever 57 located on the opposite side of the first lever 53 with respect to the first lever 53.
A spring 71 is provided to urge the first lever 53 in a direction to close the first lever 53, and the driving force of the servo meter 51 is controlled by the first lever 53, the first and second aperture blades 31 and 41, and the second lever 57.
Is transmitted to the spring 71 via the. Thus the first
And the second diaphragm blades 31 and 41 always have the spring 71
Urged in a predetermined direction by the guide pin 6
1 to 64 and the drive pins 54, 55, 58, 59 always contact the edges of the slits 33 to 36, 43 to 46.

Therefore, even if the attitude of the CCTV camera to which the aperture control device of this embodiment is mounted changes, the aperture blades 31 and 41 do not move, and the aperture of the aperture is always kept constant. Further, since there is no backlash between the pin and the slit, there is no time delay in adjusting the opening degree of the aperture, and the occurrence of hysteresis in opening / closing operation of the aperture is prevented.

Further, according to the present embodiment, the spring 7
Since 1 is provided at a portion different from the side where the servo meter 51 is provided, the axial length of the drive shaft 52 can be shortened by the length of the spring 71. In other words,
The size of the aperture control device in the optical axis direction (the size in the left-right direction in FIG. 2) can be reduced.

The first and second aperture blades 31, 4
Since 1 is always subjected to a force by the servo meter 51 or the spring 71, a certain rigidity is required, and it is preferable that the 1 is as light as possible to operate with a small driving force. Therefore, each of the diaphragm blades 31, 4
1 is formed from a light metal such as titanium.

FIGS. 6 and 7 show a diaphragm control device according to a second embodiment. FIG. 6 corresponds to FIG. 4 and FIG. 7 corresponds to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals. A configuration different from the first embodiment will be described.

The first diaphragm blade 81 is formed on the right side of the diaphragm hole 82 in FIG. 7 and extends vertically, and a first horizontal slit provided above the vertical slit 83 and extending horizontally. 84 and vertical slit 8
3 and a second horizontal slit 85 extending in the horizontal direction. Similarly, the second diaphragm blade 91 is formed on the left side of the diaphragm hole 92 and extends vertically, a first horizontal slit 94 provided above the vertical slit 93 and extending horizontally, and Slit 9
3 and a second horizontal slit 95 extending in the horizontal direction.

The drawing unit base 11 is provided with four guide pins 101, 102, 103 and 104.
The vertical slit 83 of the first diaphragm blade 81 is provided with the guide pin 10.
1 and 102, so that the first diaphragm blade 81 can move up and down along the vertical slit 83. The vertical slit 93 of the second diaphragm blade 91 is provided with guide pins 103 and 104.
Therefore, the second diaphragm blade 91 can move up and down along the vertical slit 93.

Drive pins 54 and 55 provided at both ends of the first lever 53 are provided with horizontal slits 84 and 94, respectively.
Is engaged. Driving pins 59 and 58 provided at both ends of the second driving lever 57 are respectively provided with horizontal slits 8.
5, 95 are engaged. A coil spring 71 is provided around the rotation shaft 56 of the second drive lever 57. The spring 71 urges the lever 57 in a direction in which the first and second aperture blades 81 and 91 close the opening 12.

Therefore, when the servo meter 51 is not energized and is not operated, as shown in FIG.
Reference numeral 1 denotes a raised position, the second diaphragm blade 91 is at a lowered position, and the opening 12 is closed.

On the other hand, when the servo meter 51 is energized, the first lever 53 rotates clockwise, whereby the first diaphragm blade 81 descends and the second diaphragm blade 91 rises. I do. That is, the second lever 57 rotates clockwise against the spring force of the spring 71, and the opening 12 is moved by the movement of the first and second diaphragm blades 81 and 91.
Is released.

As described above, in the second embodiment, the first and second levers 53 and 57 are configured to always rotate in the same direction.

According to the second embodiment, effects similar to those of the first embodiment can be obtained.

In each of the above embodiments, the spring 71
Has been urged in the direction to close the opening. Alternatively, it may be urged in the direction to open the opening. In this case, when the servo meter 51 is not operated, the opening is fully opened. In state.

[0035]

As described above, according to the present invention, various problems due to mechanical errors in the guide mechanism can be prevented, and the reliability and the degree of opening of the diaphragm can be adjusted with high accuracy. An aperture control device is obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an aperture control device according to a first embodiment of the present invention.

FIG. 2 is a side view of the aperture control device shown in FIG.

FIG. 3 is an exploded view showing first and second aperture blades provided in the aperture control device shown in FIG. 1;

FIG. 4 is a front view showing the aperture control device shown in FIG. 1 with a blade holding plate removed.

FIG. 5 is a diagram showing a state in which the diaphragm opening is opened by a predetermined amount in the diaphragm control device shown in FIG. 1;

FIG. 6 is a front view showing an aperture control device according to a second embodiment.

FIG. 7 is an exploded view showing first and second aperture blades provided in the aperture control device of FIG. 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 aperture unit base material 12 opening 31, 81 first aperture leaf 41, 91 second aperture leaf 53 lever (first link mechanism) 57 lever (second link mechanism) 71 spring

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 9/00-9/70

Claims (7)

(57) [Claims] An aperture unit substrate having an opening formed therein;
First and second aperture blades supported reciprocally by the aperture unit base material and capable of adjusting the opening of the opening in cooperation with each other, and connecting the first and second aperture blades. Connecting a first link mechanism, a drive source for reciprocating the first and second aperture blades by driving the first link mechanism, and the first and second aperture blades, A second link mechanism provided on a side opposite to the first link mechanism with respect to the opening;
Of the first and second aperture blades
A diaphragm control device , comprising: a spring for urging the second link mechanism in a predetermined direction in order to reduce backlash . 2. The aperture control device according to claim 1, wherein the spring biases the second link mechanism in a direction in which the opening is closed. 3. The aperture control device according to claim 1, wherein the spring urges the second link mechanism in a direction in which the opening is opened. 4. The aperture control device according to claim 1, wherein the spring is a coil spring provided around a rotation shaft of the second link mechanism. 5. The apparatus according to claim 1, wherein the first and second link mechanisms have first and second levers rotatable in a plane parallel to the aperture unit base. 3. The aperture control device according to 1. 6. The aperture control device according to claim 5, wherein said first and second levers always rotate in opposite directions. 7. The aperture control device according to claim 5, wherein the first and second levers always rotate in the same direction.