JP2001174862A - Optical diaphragm device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize fine diaphragm control by combining respective diaphragm members even though the number of diaphragm members is small. SOLUTION: This device is equipped with a fixed diaphragm plate 7 having a fixed diaphragm hole 12 positioned on an optical path from a subject to an imaging device, a 1st movable diaphragm plate 8 having a movable diaphragm hole 14 moving onto the optical path and to the outside of the optical path, and a 2nd movable diaphragm plate 21 consisting of an ND filter moving onto the optical path and to the outside of the optical path. Therefore, the device is controlled to four stages such as a totally opened diaphragm state where the plates 8 and 21 are positioned on the outside of the optical path, a 1st middle diaphragm state where only the plate 21 is positioned on the optical path, a 2nd middle diaphragm state where only the hole 14 of the plate 8 is positioned on the optical path, and a minimum diaphragm state where the hole 14 of the plate 8 and the plate 21 are superposed and positioned on the optical path. Then, the fine diaphragm control is performed by combining and using the plates 8 and 21 even though the number of the plates 8 and 21 is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical diaphragm device used for a photographing device such as an electronic camera.

[0002]

2. Description of the Related Art In general, in an electronic camera which captures an image of a subject as an electric signal by an image pickup device such as a CCD, the pixel pitch of the image pickup device is small. The effect of diffraction occurs, and a clear captured image cannot be obtained. For this reason, in the conventional aperture device, the aperture is formed in an aperture having a diameter that does not cause the influence of diffraction, and an ND filter (neutral density filter) is provided in the aperture to control the amount of light. The ND filter is a light amount adjusting filter that forms a metal film on a transparent member such as glass or plastic by vapor deposition or the like, and reduces and transmits the light amount in a predetermined frequency region such as a visible region.

FIG. 10 and FIG. 11 are diagrams showing one example. In this electronic camera, as shown in FIG. 10, a first lens group 1, an aperture device 2, a second lens group 3, an optical low-pass filter 4, and an image sensor 5 are arranged in order from the subject side (the left side in FIG. 10). 6 and the image of the subject is first,
When an image is formed on the image sensor 5 via the optical low-pass filter 4 by the second lens groups 1 and 3 for photographing, the aperture device 2
Is configured to limit the light flux, light amount, and the like from the subject. In this case, the optical low-pass filter 4 is a quartz plate or the like, and the imaging device 5 is a solid-state imaging device such as a CCD.

As shown in FIGS. 10 and 11, the diaphragm device 2 includes a fixed diaphragm plate 7 and first and second movable diaphragm plates 8 and 9.
And first and second driving devices 10 and 11. The fixed aperture plate 7 is fixed between the first range group 1 and the second lens group 3, and has a fixed aperture hole 1 substantially at the center thereof.
2 is provided on the optical axis 6. The fixed aperture hole 12 regulates an optical path width which is a light flux width around the optical axis 6 in the fully opened state. One end of the first movable diaphragm member 8 is rotatably attached to the fixed diaphragm plate 7 by the support shaft 13, and the other end has a movable diaphragm hole 14 smaller in diameter than the fixed diaphragm hole 12. The hole 14 is configured to move within a light beam (hereinafter, simply referred to as an optical path) centered on the optical axis 6 overlapping the fixed aperture hole 12 and outside the optical path not overlapping the fixed aperture hole 12.

The second movable diaphragm plate 9 is, like the first movable diaphragm plate 8, one end rotatably mounted on the fixed diaphragm plate 7 by a support shaft 13 and the other end of the first movable diaphragm plate 8. A diaphragm hole 15 having a diameter substantially equal to or smaller than the movable diaphragm hole 14 is provided, and an ND filter 16 is provided so as to cover the diaphragm hole 15. The diaphragm hole 15 covered with the ND filter 16 is a fixed diaphragm. It is configured to move on the optical path overlapping with the hole 12 and outside the optical path that does not overlap. In this case, the aperture 15 of the second movable aperture plate 9 is formed to a size that does not affect the diffraction during imaging.

The first driving device 10 drives the first movable diaphragm plate 8, and the second driving device 11 drives the second movable diaphragm plate 9, both of which have the same configuration. Note that FIG. 11 shows only the second driving device 11, and the second driving device 11 will be described below. The second driving device 11 includes a motor 17 and a rotating arm 18 attached to the motor 17, and a tip of the rotating arm 18 is connected to a second movable diaphragm plate 9 by a connecting pin 19.
The rotation arm 18 rotates by the rotation of the motor 17, and the second movable diaphragm plate 9 rotates about the support shaft 13 with the rotation of the rotation arm 18.
The aperture hole 15 covered by the ND filter 16 is configured to move on the optical path and outside the optical path.

[0007]

The diaphragm device 2 described above
Then, the first and second movable diaphragm plates 8 and 9 are moved by the first and second driving devices 10 and 11, respectively, and the movable diaphragm hole 14 of the first movable diaphragm plate 8 and the second movable diaphragm plate 9 are moved. By positioning the aperture 15 covered with the ND filter 16 outside the optical path, a fully-open aperture state in which the amount of light is adjusted only by the fixed aperture 12 of the fixed aperture plate 7, and a first drive of the first movable aperture plate 8 The movable aperture 14 of the first movable aperture plate 8 is moved by the apparatus 10 so as to overlap the fixed aperture 12 of the fixed aperture plate 7, so that the amount of light is adjusted by the movable aperture 14 of the first movable aperture plate 8. The aperture state and the aperture 15 covered by the ND filter 16 of the second movable aperture plate 9 are overlapped with the fixed aperture 12 of the fixed aperture plate 7 by moving the second movable aperture plate 9 by the second driving device 11. As a result, the N of the second movable diaphragm plate 9
The aperture is controlled in three stages of a minimum aperture state in which the light amount is adjusted by the D filter 16 and the aperture hole 15.

However, the aperture device 2 has a fully-opened state in which the amount of light is adjusted only by the fixed aperture 12 of the fixed aperture plate 7 and an intermediate aperture state in which the amount of light is adjusted by the movable aperture 14 of the first movable aperture plate 8. Since the aperture control is a three-stage aperture control in which the amount of light is adjusted by the ND filter 16 and the aperture hole 15 of the second movable aperture plate 9, there is a disadvantage that fine aperture control cannot be performed. In order to perform fine aperture control, it is conceivable to increase the number of the first movable aperture plates 8. However, simply increasing the number of the first movable aperture plates 8 not only complicates the structure but also increases the light intensity. Since the thickness of the entire diaphragm device 2 in the direction along the axis 6 increases, the optical design is disadvantageous. Such a problem arises from the fact that the first and second movable diaphragm plates 8 and 9 cannot be combined and used in an overlapping manner.

An object of the present invention is to enable fine aperture control by using a combination of the first and second aperture members even if the number of aperture members is small.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an optical diaphragm apparatus for adjusting the amount of light from a subject to an image pickup unit, which has a stop hole that moves on the optical path from the subject to the image pickup unit and outside the optical path. It is characterized by comprising a first stop member and a second stop member comprising a light amount adjusting filter that moves on the optical path and outside the optical path. According to the present invention, a fully opened state in which the first and second diaphragm members are located outside the optical path, and a first intermediate diaphragm state in which only the second diaphragm member including the light amount adjusting filter is located in the optical path, A second intermediate aperture state where only the aperture of the first aperture member is located on the optical path, and a minimum aperture state where the aperture of the first aperture member and the second aperture member are overlapped and located on the optical path. The control can be performed in four stages. Therefore, even if the number of diaphragm members is small, fine diaphragm control can be performed by using the first and second diaphragm members in combination.

In this case, it is preferable that a fixed stop member that is located on the optical path and has a diameter larger than the diameter of the stop hole of the first stop member is provided. Also, as described in claim 3, the first throttle member is formed of one first movable plate provided with a plurality of the apertures having different diameters or a plurality of first movable plates provided with the apertures having different diameters. With such a configuration, finer aperture control can be performed than in the first aspect of the invention. Claim 4
As described in above, the second diaphragm member is one second movable plate made of a light amount adjusting filter having a specific transmittance or one second movable plate made of a light amount adjusting filter having a plurality of regions having different transmittances. With a movable plate or a configuration including a plurality of second movable plates each including a light amount adjusting filter having a different transmittance, fine aperture control can also be performed. Particularly, when the invention described in claim 3 and the invention described in claim 4 are combined, finer aperture control can be performed. Further, according to claim 5, the first
If there is provided a drive unit for independently driving the aperture member and the second aperture member, and a control unit for controlling the operation of the drive unit, the control unit can make the aperture state optimal.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the aperture device according to the present invention will be described below with reference to FIGS. The same parts as those in the conventional example shown in FIGS. 10 and 11 are denoted by the same reference numerals and described. The aperture device 20 is disposed between the first lens group 1 and the second lens group 3 of the electronic camera, as in the conventional example shown in FIG.
The structure of the second movable diaphragm plate 21 is different from that of the conventional example, and is otherwise substantially the same as that of the conventional example. That is, the diaphragm device 20 includes a fixed diaphragm plate 7 and a first movable diaphragm plate 8.
, The second movable diaphragm plate 21, the first and second driving devices 10,
And a control unit (not shown) for controlling the driving devices 10 and 11.

In this case, the second movable diaphragm plate 21 is formed by depositing a metal film on a transparent member such as glass or plastic by vapor deposition or the like, and reduces the amount of light in a predetermined frequency region such as a visible region and transmits the light. It is composed of only an ND filter which is a filter. One end of the second movable diaphragm plate 21 is rotatably attached to the fixed diaphragm plate 7 by the support shaft 22, and the other end overlaps the fixed diaphragm hole 12 of the fixed diaphragm plate 7 to form the fixed diaphragm hole 12. Light path to block (as before,
(The light flux area around the optical axis 6) and outside the optical path that does not overlap with the fixed aperture hole 12. As shown in FIG. 2, the second movable diaphragm plate 21 is raised in the direction along the optical path by the support shaft 22 by the thickness of the first movable diaphragm plate 8 so as not to abut on the first movable diaphragm plate 8. Supported.

The control unit is a central processing unit that controls the operation of the entire circuit of the electronic camera in accordance with a program registered in advance. The control unit includes an image pickup device 5, which is an input / output peripheral device, first and second drive units 10, In addition to 11, a storage unit (not shown), an exposure unit, various switches, and the like are connected, and control these operations according to an input / output program. That is, the control unit performs the first,
By controlling the operation of the second driving devices 10 and 11,
The movable diaphragm hole 14 of the first movable diaphragm plate 8 is selectively moved on the optical path and outside the optical path, and the second movable diaphragm plate 21 is selectively moved on the optical path and outside the optical path.

In such an aperture device 20, the first and second
The movable diaphragm plates 8 and 21 are respectively connected to the first and second driving devices 1
1 and the movable diaphragm hole 14 of the first movable diaphragm plate 8 and the second movable diaphragm plate 21 are positioned outside the optical path as shown in FIG. A fully opened state in which the light amount is adjusted only by the hole 12 is obtained. Further, by moving the second movable diaphragm plate 21 by the second driving device 11 and superposing only the second movable diaphragm plate 21 on the fixed diaphragm hole 12 of the fixed diaphragm plate 7 as shown in FIG.
The first intermediate aperture state is set in which the amount of light is adjusted by the ND filter of the second movable aperture plate 21.

The first movable diaphragm plate 8 is connected to the first driving device 1.
0, the first movable diaphragm plate 8 is moved as shown in FIG.
The movable aperture hole 14 of the first movable aperture plate 8 is overlapped with the fixed aperture hole 12 of the fixed aperture plate 7, so that a second intermediate aperture state in which the light amount is adjusted by the movable aperture hole 14 of the first movable aperture plate 8. Further, the first and second movable diaphragm plates 8 and 21 are moved by the first and second driving devices 10 and 11, respectively, to fix the movable diaphragm holes 14 of the first movable diaphragm plate 8 as shown in FIG. The first movable diaphragm plate 8 is overlapped with the fixed diaphragm hole 12 of the diaphragm plate 7 and the ND filter of the second movable diaphragm plate 21 is overlapped with the movable diaphragm hole 14 and the fixed diaphragm hole 12.
The minimum aperture state in which the amount of light is adjusted by the movable aperture hole 14 and the ND filter of the second movable aperture plate 21 is achieved.

As described above, according to the diaphragm device 20,
Since the second movable diaphragm plate 21 is formed of an ND filter, the first movable diaphragm plate 8 and the second movable diaphragm plate 21 are located outside the optical path in a fully open state, and only the second movable diaphragm plate 21 composed of an ND filter is provided. A first intermediate stop state in which is positioned on the optical path;
The second intermediate aperture state in which only the movable aperture hole 14 of the first movable aperture plate 8 is located on the optical path, and the movable aperture hole 14 of the first movable aperture plate 8 and the second movable aperture plate 21 are superimposed on each other. It can be controlled to the minimum aperture state located on the road, so that even if the number of the first and second movable aperture plates 8 and 21 is as small as two, the first and second movable aperture plates 8 and 21 can be controlled. By using in combination, the aperture control can be performed in four stages as a whole, so that the aperture control can be performed more finely than in the conventional example. Also,
In this diaphragm device 20, since the second movable diaphragm plate 21 is composed of only the ND filter, the second movable diaphragm plate 9 of the related art is used.
The thickness of the diaphragm device 20 can be made thinner than the thickness of the diaphragm device 20, and the optical design can be made advantageous.

In the above embodiment, the case where one fixed movable diaphragm plate 8 is provided on the fixed diaphragm plate 7 has been described. However, the present invention is not limited to this. For example, the first modified example shown in FIG. As described above, a structure in which the two first movable diaphragm plates 25 and 26 are each rotatably mounted on the support shaft 27 may be used.
In this case, the first movable aperture plates 25 and 26 are respectively formed with movable aperture holes 25a and 26a having a smaller diameter than the fixed aperture 12 of the fixed aperture plate 7 and having different sizes. I have. In such a structure, since the first movable diaphragm plates 25 and 26 are two, the diaphragm can be controlled in six stages by a combination of the first movable diaphragm plates 25 and 26 and the second movable diaphragm plate 21. Can be. in this case,
If the structure is such that the two first movable diaphragm plates 25 and 26 rotate in the same plane, the thickness of the entire apparatus can be made not to increase in the direction along the optical axis 6. The number of such first movable diaphragm plates does not need to be two, and three or more diaphragm plates may be provided to perform finer diaphragm control.

In the above embodiment, the case where one movable aperture hole 14 is provided in one first movable aperture plate 8 has been described. However, the present invention is not limited to this. For example, the second movable aperture plate 14 shown in FIG.
As in a modified example, a configuration in which a plurality of movable aperture holes 28a and 28b are provided in one first movable aperture plate 28 may be used. In this case, each of the movable throttle holes 28a and 28b is formed to have a diameter smaller than the diameter of the fixed throttle hole 12 of the fixed throttle plate 7 and to have different sizes. In such a structure, the amount of movement of the first movable diaphragm plate 28 is controlled so that one of the movable diaphragm holes 28 a and 28 b is selectively fixed to the fixed diaphragm plate 7.
The aperture can be controlled in six stages without increasing the number of the first movable aperture plates 28 by overlapping the fixed aperture 12 with. Also in this case, the first movable diaphragm plate 2
The number of the movable apertures 28a and 28b provided in the nozzle 8 need not be two, and three or more movable apertures having different diameters may be provided to perform finer aperture control.

Further, in the above embodiment, the fixed aperture plate 7
In the above, the case where one second movable diaphragm plate 21 is provided has been described. However, the present invention is not limited to this. For example, as in the third modification shown in FIG. Alternatively, a structure may be employed in which each of the bases 31 is rotatably attached by a support shaft 32. In this case, the two second movable diaphragm plates 30 and 31 are composed of ND filters having different transmittances, respectively,
The heights in the direction along are the same or different. In such a structure, when the two second movable diaphragm plates 30 and 31 have the same height, the two second movable diaphragm plates 30 and 31 overlap the fixed diaphragm plate 7 and the first movable diaphragm plate 8. Thus, the aperture can be controlled in six steps, and when the heights of the two second movable aperture plates 30 and 31 are different, the aperture can be controlled in eight steps. The number of such second movable diaphragm plates does not need to be two, and three or more diaphragm plates may be provided to perform finer diaphragm control.

In the third modification, the two second movable diaphragm plates 30 and 31 are respectively formed by ND filters having different transmittances. However, the present invention is not limited to this. As in the fourth modification, a single second movable diaphragm plate 35 may be constituted by an ND filter having a plurality of regions (two regions 36 and 37 in the figure) having different transmittances. In this case, the ND filter provides the transparent member with a first transmittance having a specific transmittance.
By forming a metal layer and forming a second metal layer having another different transmittance at a predetermined location (substantially half location) on the first metal layer, a plurality of regions having different transmittances in one ND filter 36 and 37 are formed. Even with such a structure using the second movable diaphragm plate 35,
Similar to the third modification, fine aperture control can be performed.
Since only one movable diaphragm plate 35 is required, the second driving device 11 is simplified, and the cost can be reduced.

Further, in the first to fourth modifications, the first
The number of the movable diaphragm plates, the number of the movable diaphragm holes of the first movable diaphragm plate, the number of the second movable diaphragm plates, and the number of regions having different transmittances are simply increased, respectively. A structure combining the first to fourth modified examples may be adopted. For example, two or more first movable diaphragm plates 25 and 26 are provided as in the first modified example shown in FIG. 6, and the second movable diaphragm plate 30 and the second movable diaphragm plate 30 are made as in the third modified example shown in FIG. 31
May be provided, or a structure in which the second movable diaphragm plate 35 is provided as in the fourth modification shown in FIG. Further, as in the second modification shown in FIG. 7, a plurality of movable aperture holes 28 are provided in one first movable aperture plate 28.
a and 28b and a structure in which two or more second movable diaphragm plates 30 and 31 are provided as in a third modification shown in FIG. 8, and a fourth modification shown in FIG. A structure in which the second movable diaphragm plate 35 is provided as in the example may be employed. With such a structure, very fine aperture control can be performed.

[0023]

As described above, according to the present invention, the first stop member having the stop hole which moves on the optical path from the subject to the imaging section and outside the optical path, Since there is provided a second aperture member made of a moving light amount adjusting filter, only a fully opened state where the first and second aperture members are located outside the optical path and only a second aperture member made of a light amount adjusting filter are provided. A first intermediate aperture state located on the optical path, a second intermediate aperture state where only the aperture of the first aperture member is located on the optical path, a movable aperture of the first aperture member, and a second
It can be controlled in four stages, that is, the minimum stop state in which the stop member is superimposed and positioned on the optical path, so that even if the number of stop members is small, the first and second stop members are used in combination. This enables fine aperture control.

In this case, the first throttle member may be constituted by one first movable plate provided with a plurality of apertures having different diameters or a plurality of first movable plates provided with apertures having different diameters. If this is the case, finer aperture control can be performed. In addition, the second diaphragm member is one second movable plate made of a light amount adjusting filter having a specific transmittance, or one second movable plate made of a light amount adjusting filter having a plurality of regions having different transmittances. Alternatively, a fine aperture control can also be performed by using a configuration including a plurality of second movable plates each including a light amount adjustment filter having a different transmittance.
In particular, if a structure combining these is used,
Fine aperture control is possible.

[Brief description of the drawings]

FIG. 1 is an enlarged front view showing a fully opened state of a diaphragm device according to an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is an enlarged front view showing a first intermediate stop state in the stop device of FIG. 1;

FIG. 4 is an enlarged front view showing a second intermediate aperture state in the aperture device of FIG. 1;

FIG. 5 is an enlarged front view showing a minimum aperture state in the aperture device of FIG. 1;

FIG. 6 is an enlarged front view showing a first modification of the aperture device of the present invention.

FIG. 7 is an enlarged front view showing a second modification of the aperture device of the present invention.

FIG. 8 is an enlarged front view showing a third modification of the aperture device of the present invention.

FIG. 9 is an enlarged front view showing a fourth modification of the aperture device of the present invention.

FIG. 10 is a diagram schematically illustrating an overall configuration of an electronic camera.

FIG. 11 is an enlarged front view showing a part of the conventional aperture device in a partially omitted manner.

[Explanation of symbols]

 Reference Signs List 5 imaging element 7 fixed aperture plate 8, 25, 26, 28 first movable aperture plate 10 first drive device 11 second drive device 12 fixed aperture hole 14, 25a, 26a, 28a, 28b movable aperture hole 20 aperture device 21, 30, 31, 35 Second movable diaphragm plate 36, 37 Region of different transmittance

Claims (5)

[Claims] 1. An optical diaphragm device for adjusting the amount of light from a subject to an image pickup unit, comprising: a first stop member having a stop hole moving on an optical path from the subject to the image pickup unit and outside the optical path; An optical diaphragm device comprising: a second diaphragm member including a light amount adjusting filter that moves on a road and outside the optical path. 2. The apparatus according to claim 1, further comprising a fixed diaphragm member located on the optical path and having a diaphragm hole having a diameter larger than a diameter of a movable diaphragm hole of the first diaphragm member. Optical diaphragm device. 3. The first diaphragm member comprises one first movable plate provided with a plurality of apertures having different diameters, or a plurality of first movable plates provided with the apertures having different diameters. The optical diaphragm device according to claim 1, wherein: 4. The second diaphragm according to claim 1, wherein the second diaphragm is a second movable plate made of a light amount adjusting filter having a specific transmittance, or a second light adjusting member made of a light amount adjusting filter having a plurality of regions having different transmittances. The optical diaphragm device according to claim 1, comprising two movable plates or a plurality of second movable plates each including a light amount adjustment filter having a different transmittance. 5. The apparatus according to claim 1, further comprising driving means for driving said first and second diaphragm members independently, and control means for controlling the operation of said driving means.
6. The optical diaphragm device according to 5.