JPH0590457U - Light intensity adjustment device - Google Patents

Abstract

(57) [Abstract] [Purpose] In a device of a type in which a connecting member for connecting an opening / closing member such as an aperture blade and the driving unit are not directly connected, an engaging hole such as a slit and an engaging protrusion such as a pin By reducing the total amount of backlash due to the clearance as much as possible, the opening / closing operation of the opening / closing member is smooth, thereby improving the optical accuracy. [Structure] First slit 9 formed in first blade 4
And a second slit 10 and a third slit 11 formed in the second blade 5, and pins 12 and 13 that engage with the first slit 9 and the second slit 10, respectively, and an intermediate portion. And a pin 16 that engages with the third slit 6
And a rotating arm 17 connected to the drive unit.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a light amount adjusting device such as a diaphragm device and a shutter in a camera such as a video camera.

[0002]

[Prior Art]

 Generally, a light quantity adjusting device such as a diaphragm device of a video camera has two diaphragm blades slidably provided in a direction orthogonal to the optical axis in a direction in which they come close to and away from each other (relatively opposite directions), A notch formed in each of these two blades and having a light-receiving area that changes depending on the proximity / separation of the two blades; and a drive mechanism for sliding the two blades in a direction of approaching / separating from each other. Those equipped with are known.

A conventional example of this type of apparatus is shown in FIG. In FIG. 2, 30 is a light receiving opening formed in the base plate 41, 31 and 32 are blades, and 33 is a notch. Slits 34 and 35 are formed in the two blades 31 and 32, respectively. A connecting lever 38 having pins 36 and 37 that engage with the slits 34 and 35 is connected to a drive unit 40 so as to be rotatable about a shaft 39. However, depending on the structure of the camera, there is a case where the device of the type shown in FIG. 2 in which the drive unit 40 is directly connected to the connecting lever 38 is not applicable.

Therefore, depending on the structure of the camera, as shown in Japanese Utility Model Laid-Open No. 62-84031 and FIG. 3, the drive unit and the connecting lever are not directly connected, but are connected between the drive unit and the connecting lever. There is no choice but to adopt a structure that interposes a moving arm.

In FIG. 3, two diaphragm blades 51 and 52 are provided with slits 53 and 54, respectively. A connecting lever 57 having pins 55 and 56 that engage with the slits 53 and 54 at one end is provided. A slit 58 is formed on one end side of the connecting lever 57, and a rotating arm 60 having a pin 59 that engages with the slit 58 is provided, and the other end of the rotating arm 60 is connected to the drive portion 61. ing.

[0006]

[Problems to be solved by the device]

 By the way, the apparatus of FIG. 2 is configured to transmit the drive of the drive unit 40 to the blades 31, 32 via only the connecting lever 38. On the other hand, the device of FIG. 3 is configured to transmit the drive of the drive unit 61 to the blades 51 and 52 via the rotating arm 60 and the connecting lever 57. Therefore, the device of FIG. 3 has more power transmission links than the device of FIG. 2, and therefore the total amount of play due to the clearance of the engaging portion between the slit and the pin increases. Therefore, the apparatus of FIG. 3 has a problem in that the blades are not smoothly moved toward and away from each other as compared with the apparatus of FIG. 2 and the optical accuracy is inferior.

An object of the present invention is to provide a device of a type in which a connecting member for connecting an opening / closing member such as a diaphragm blade and a driving unit are not directly connected to each other, in which an engaging hole such as a slit and an engaging protrusion such as a pin are connected. It is an object of the present invention to obtain a light quantity adjusting device in which the opening / closing operation of the opening / closing member is smooth and the optical accuracy is improved by reducing the total amount of backlash due to the clearance.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is directed to a light amount adjusting device that moves the first and second opening / closing members in opposite directions along the light receiving opening to adjust the amount of light passing through the light receiving opening. In the above, the first and second opening / closing members are connected by a connecting member that rotates around a fulcrum, and the connecting member causes the first and second opening / closing members to interlock with each other, and is also rotated by a drive unit. A driving member connected to one of the opening / closing members, and the driving force of the driving unit is transmitted to one of the opening / closing members via the driving member.

Further, a first engaging hole formed in the first opening / closing member, a second engaging hole and a third engaging hole formed in the second opening / closing member, and the first engaging hole A connecting member having first and second engaging projections that engage with the first engaging hole and the second engaging hole, and is rotatable about a rotation fulcrum; and the third engaging hole. A drive member having a third engagement protrusion that engages with the drive member, and a drive unit that rotates the drive member.

[0010]

[Action]

 In this invention, the first and second opening / closing members are connected by a connecting member that rotates about a fulcrum, and the connecting member causes the first and second opening / closing members to interlock with each other, and is rotated by the drive unit. The driving member is connected to one of the opening / closing members, and the driving force of the driving unit is transmitted to one of the opening / closing members via the driving member.

Here, the total amount of backlash between the conventional example of FIG. 3 and this device (see FIG. 1) will be compared.

In general, the opening / closing member is a very thin sheet having an engaging hole, and thus can be formed by precision press processing. On the other hand, the connecting member and the driving member have engaging protrusions and are often formed by molding. The molding accuracy is inferior to the precision press. Therefore, even with the same engagement hole, the dimensions of the engagement holes of the molded connecting member and the driving member are inferior in accuracy to the dimensions of the engagement holes of the opening / closing member made of precision press. Therefore, if the required clearance of the connecting portion between the engaging hole of the connecting member or the drive member and the engaging protrusion is a, and the required clearance of the connecting portion between the engaging hole of the opening / closing member and the engaging protrusion is b, then a is It becomes larger than b (a> b).

In the conventional example of FIG. 3, the driving force of the driving unit is transmitted to the first opening / closing member and the second opening / closing member via the driving member and the connecting member. That is, the power transmission path includes a drive member-> coupling member-> first opening / closing member path and a drive member-> connecting member-> second opening / closing member path. The required clearance of the former route is a for the drive member → connecting member and b for the connecting member → first opening / closing member. The required clearance of the latter path is a for the drive member → coupling member and b for the coupling member → second opening / closing member. Therefore, the total amount of backlash in the conventional example of FIG. 3 is (2a + 2b).

On the other hand, in the present invention, the driving force of the driving unit is transmitted to the second opening / closing member via the driving member on the one hand and via the driving member, the second opening / closing member and the connecting member on the other hand. It is transmitted to the first opening / closing member. That is, as the power transmission path, there are a path of the driving member → the second opening / closing member and a path of the driving member → the second opening / closing member → the connecting member → the first opening / closing member. The required clearance of the former route is b from the drive member to the second opening / closing member. The required clearance of the latter path is b for the drive member → the second opening / closing member, b for the second opening / closing member → the connecting member, and b for the connecting member → the first opening / closing member. Therefore, the total amount of backlash in this device is 4b.

That is, the total amount of play in the conventional example of FIG. 3 is (2a + 2b), and the total amount of play in this invention is 4b. By the way, since a> b as described above, the backlash of the present invention is smaller than that of the conventional example of FIG.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. This embodiment shows a diaphragm device used for a video camera or the like. <Structure> A base plate 1 is formed with a circular opening (light receiving opening) 2. The opening 2 faces an image pickup lens (not shown). Slits 6 formed on the opening / closing member, for example, the first diaphragm blade 4 and the second diaphragm blade 5 are engaged with a plurality of pins 3 projecting from the base plate 2. That is, the first blade 4 and the second blade 5 are slidable in a direction in which they approach and separate from each other on a surface orthogonal to the optical axis. The first blade 4 and the second blade 5 are formed with notches 7 and 8 whose light-receiving area (overlap area) changes as the blades 4 and 5 approach and separate, respectively. A first engaging hole, for example, a slit 9 is formed on one side of the first blade 4. A second engaging hole such as a slit 10 and a third engaging hole such as a slit 11 are formed on the same one side of the second blade 5. Here, the blades 4 and 5 are, for example, synthetic resin sheets of several tens of microns to several hundreds of micron and are formed by precision press working.

A connecting member, for example, a connecting member, having engaging projections, for example, pins 12 and 13 which engage with the first slit 9 of the first blade 4 and the second slit 10 of the second blade 5, respectively, at both ends. A connecting lever 14 is provided. The connecting lever 14 is rotatable about an intermediate shaft 15 and the distance between the shaft 15 and the pin 12 and the distance between the shaft 15 and the pin 13 are equal.

Further, a driving member, for example, a rotating arm 17 having a pin 16 engaging with the third slit 11 of the second blade 5 at one end side is provided. The other end of the rotating arm 17 is connected to the rotary shaft 19 of the drive unit 18. The drive unit 18 has a built-in motor (not shown) that rotates by a predetermined angle. Here, the connecting lever 14 and the rotating arm 17 are formed by molding. The diaphragm blades 4 and 5 slidably mounted on the main plate 1 are covered with a cover (not shown).

<Operation> The drive of the drive unit 18 is transmitted to the second blade 5 via the rotating arm 17 on the one hand and via the rotating arm 17, the second blade 5 and the connecting lever 14 on the other hand. Is transmitted to the first blade 4. When the drive unit 18 is driven clockwise in the figure, the first blade 4 and the second blade 5 move in a direction in which they are separated from each other (a light-transmitting area decreases). On the other hand, when the drive unit 18 drives in the counterclockwise direction, the first blade 4 and the second blade 5 move in the direction in which they approach each other (the light receiving area increases).

<Effects of Embodiment> In this embodiment, the driving force of the drive unit 18 is transmitted to the second diaphragm blade 5 via the rotating arm 18 on the one hand, and the rotating arm 17 and the second arm 5 on the other hand. It is transmitted to the first diaphragm blade 4 via the diaphragm blade 5 and the connecting lever 14.

Here, the total amount of backlash between the conventional example of FIG. 3 and the embodiment of FIG. 1 is compared. Since the diaphragm blade is generally a very thin sheet made of synthetic resin having slits, it is formed by precision pressing, but the connecting lever and the pivot arm have pins and are formed by molding. Molding is inferior to precision presses in processing accuracy.Therefore, even with the same slit, the dimensions of the slits of the connecting lever and rotary arm made of molds are more accurate than those of the blades of precision presses. Inferior Therefore, if the required clearance of the connecting portion between the connecting lever and the slit of the rotating arm and the pin is a, and the required clearance of the connecting portion between the blade slit and the pin is b, a becomes larger than b (a> b). ).

In the conventional example of FIG. 3, the driving force of the drive unit 16 is transmitted to the first blade 51 and the second blade 52 via the rotating arm 60 and the connecting lever 57. That is, the dynamic force transmission path includes a path of the rotating arm 60 → the connecting lever 57 → the first blade 51, and a path of the rotating lever 60 → the connecting lever 57 → the second blade 52. The required clearance of the former route is a for the rotating arm 60 → the connecting lever 57 and a for the connecting lever 57 → the first blade 51. The necessary clearance of the latter path is a for the rotating arm 60 → the connecting lever 57 and a for the connecting lever 57 → the second blade 52. Therefore, the total amount of backlash in the conventional example of FIG. 3 is (2a + 2b).

On the other hand, in the embodiment of FIG. 1, the driving force of the driving unit 18 is transmitted to the second blade 5 via the rotating arm 17 on the one hand, and the rotating arm 17 and the second blade 5 on the other hand. It is transmitted to the first blade 4 via the blade 5 and the connecting lever 14. That is, the power transmission path includes a path of the rotating arm 17 → the second blade 5 and a path of the rotating arm 17 → the second blade 5 → the connecting lever 14 → the first blade 4. The required clearance of the former route is b from the rotating arm 17 to the second blade 5. The necessary clearance for the latter path is: rotating arm 17 → b for second blade 5, second blade 5 → b for connecting lever 17 and b for connecting lever 17 → first blade 4. Therefore, the total amount of backlash in this embodiment is 4b.

That is, the total amount of play in the conventional example of FIG. 3 is (2a + 2b), and the total amount of play in this embodiment is 4b. By the way, since a> b as described above, the backlash of this embodiment is smaller than that of the conventional example of FIG. Therefore, the opening / closing operation of the diaphragm blades 4 and 5 is smoother than that of the apparatus of FIG. 3, and the optical accuracy is high.

<Modification> The present invention is not limited to the above embodiment, and various embodiments can be implemented. For example, although the diaphragm device is used in the above embodiment, it may be applied to a shutter or the like. Although the guide of the diaphragm blades 4 and 5 is performed by the pin 3, a guide side plate may be provided on the side surface of the base plate 1 and the side edges of the diaphragm blades 4 and 5 may be brought into contact with this side plate for guiding. The slits 9, 10 and 11 may be round holes depending on the structure of the diaphragm device.

[Effect of the device]

 As described above, in the present invention, the drive of the drive unit is transmitted to the second opening / closing member via the drive member on the one hand and the first member via the drive member, the second opening / closing member and the connecting member on the other hand. Is transmitted to the opening / closing member. That is, since the opening / closing member is formed with the engaging hole with which the engaging protrusion of the driving member engages and the engaging hole with which the engaging protrusion of the connecting member engages, the total amount of play due to the clearance of the connecting portion can be reduced. As a result, the operation of the opening / closing member becomes smooth, and thus the optical accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional diaphragm device.

FIG. 3 is a diagram showing a configuration of a conventional diaphragm device.

[Explanation of symbols]

 4 1st diaphragm blade (1st opening / closing member) 5 2nd diaphragm blade (2nd opening / closing member) 9 1st slit (1st engagement hole) 10 2nd slit (2nd engagement) Hole 11 third slit (third engaging hole) 12 pin (first engaging protrusion) 13 pin (second engaging protrusion) 14 connecting lever (connecting member) 16 pin (third engaging) 17) Rotating arm (driving member) 18 Driving unit

Claims (2)

[Scope of utility model registration request] 1. A light quantity adjusting device for adjusting the quantity of light passing through the light receiving opening by relatively moving first and second opening / closing members in opposite directions along the light receiving opening. The opening / closing member is connected by a connecting member that rotates about a fulcrum, and the connecting member causes the first and second opening / closing members to interlock with each other, and the drive member rotated by the drive unit is connected to the opening / closing member. A light amount adjusting device, wherein the light amount adjusting device is connected to one side and transmits the driving force of the driving unit to one of the opening / closing members via the driving member. 2. A light amount adjusting device for adjusting the amount of light passing through the light receiving opening by moving the first and second opening and closing members in relatively opposite directions along the light receiving opening. A first engaging hole formed in the first opening, a second engaging hole and a third engaging hole formed in the second opening / closing member, the first engaging hole and the second engaging First and second engaging holes
And a driving member having a third engaging protrusion that engages with the third engaging hole, and a connecting member that is rotatable about a rotation fulcrum. A light quantity adjusting device comprising: a drive unit for moving the light quantity.