JP2003035922A - Diaphragm device of optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diaphragm device of an optical system which has a mechanical shutter function and is capable of reducing a size by suppressing the stroke in a moving direction of diaphragm blades. SOLUTION: This diaphragm device consists of a combination of the three diaphragm blades 47, 58 and 73 and the first diaphragm blade 47b is mounted with an ND filter 49 so as to cover its notch 48. On the other hand, the second diaphragm blade 58 is not provided with the filter. The third diaphragm blade 73 is mounted with a filter 75 having a density difference of >=2 steps so as to cover a portion of its opening 74. The first diaphragm blade 47 and the second diaphragm blade 58 are moved in directions opposite to each other by means of a motor 52. The third diaphragm blade 73 is independently moved in the same direction as the direction of the second diaphragm blade 58 by another motor 78.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm device for an optical system, and more particularly to a diaphragm device for an optical system that adjusts an aperture amount by moving diaphragm blades on a plane intersecting the optical axis.

[0002]

2. Description of the Related Art In an optical system of an image pickup apparatus such as a still camera or a video camera, a so-called iris diaphragm for rotating a plurality of diaphragm blades around an optical axis to adjust the diaphragm diameter is used instead of an optical axis. A small, lightweight, and low-cost diaphragm device in which the aperture amount is adjusted by using two diaphragm blades that move in opposite directions on a straight line is being used.

For example, in Japanese Unexamined Patent Publication No. 2001-117133, as shown in FIG. 4, a flat housing having a first diaphragm blade 1, a second diaphragm blade 2 and a third diaphragm blade 3 in common. A diaphragm device which is arranged inside the body 4 has been proposed.

Here, an ND filter (Neutral-density filter) 5 is provided on the first diaphragm blade 1.
However, an ND filter 6 is attached to the third diaphragm blade 3. The three diaphragm blades 1, 2, 3 are supported by a plurality of pins 7 provided on the inner surface of the housing 4 so as to be vertically movable in a direction orthogonal to the optical axis.

The pin 11 of the drive arm 10 fixed to the output shaft of the small motor 9 is engaged with the engaging hole 14 of the first diaphragm blade 1.
So that the second pin 12 is engaged with the engagement hole 15 of the second diaphragm blade and the third pin 13 is engaged with the engagement hole 16 of the third diaphragm blade 3. Has become.

Therefore, when the drive arm 10 is rotationally driven by the motor 9, the diaphragm blades 2 and 3 move in opposite directions. The first diaphragm blade 1 moves in the same direction as the second diaphragm blade 2 with a phase shift. Therefore, the combination of these three diaphragm blades 1, 2, and 3 changes the aperture amount of the aperture and the positional relationship between the ND filters 5 and 6 that cover the apertures, which makes it possible to adjust the aperture amount. .

Further, Japanese Patent Laid-Open No. 2000-122109 discloses a diaphragm device as shown in FIG. This diaphragm device includes a first housing blade 21 in a flat casing 20,
The second diaphragm blade 22 and the third diaphragm blade 23 are slidably arranged. Here, an ND filter 24 is attached to the third diaphragm blade 23.

Further, here, the casing 20 is divided into front and rear by a partition plate 25, and a first diaphragm blade 21 and a second diaphragm blade 22 are arranged on one side of the partition plate 25. On the other hand, the third diaphragm blade 23 is arranged in the space on the opposite side of the partition plate 25. The three diaphragm blades 21, 22, and 23 are vertically slidably guided by four pins 26 that are planted on the inner surface of the housing 20. The partition plate 25 is positioned and held by the pin 26. Then, the cover plate 27 is attached so as to cover the opening of the housing 20.

Here, a pair of motors 29 serving as driving means,
35 is used. One motor 29 is a drive arm 30
Are provided with pins 31 and 32 respectively at both ends, the pin 31 is engaged with the engagement hole 33 of the first diaphragm blade 21, and the pin 32 is engaged with the engagement hole 34 of the second diaphragm blade 22.

Further, the drive arm 3 is attached to the output shaft of the motor 35.
In such a structure in which 6 is fixed and the pin 37 implanted at the tip of the arm 36 is engaged with the elongated hole 38 of the third diaphragm blade 23, the motor 29 is driven to drive the drive arm. When 30 is rotated, a pair of diaphragm blades 2
Nos. 1 and 22 move in the opposite directions to each other, whereby the diaphragm amount is adjusted. On the other hand, another motor 3
When 5 is driven, the third diaphragm blade 23 moves, and the displacement amount of the ND filter 24 changes, which makes it possible to change the density of the ND filter that covers the aperture.

[0011]

[Problems to be Solved by the Invention]
The diaphragm device disclosed in Japanese Patent No. 133, which is shown in FIG. 4, employs a structure in which three diaphragm blades 1, 2 and 3 are moved by a single motor 9, and therefore, the diaphragm blades. The remaining two diaphragm blades 2 and 3 cannot be independently moved with respect to 1. The disadvantage of such a structure is that the mechanical shutter operation using the second diaphragm blade 2 and the third diaphragm blade 3 cannot be performed. That is, since it has only a function as a diaphragm and no shutter function, it cannot be applied to the still operation.

On the other hand, Japanese Unexamined Patent Publication No. 2000-122109
The diaphragm device disclosed in Japanese Patent Laid-Open Publication No. 2003-242242 has an ND filter 24 having three densities and a diaphragm blade 23.
Must be installed on. In particular, the smaller the size of the three-density ND filter, the more difficult it becomes to manufacture, which causes a problem of increased manufacturing cost. Since the ND filter 24 is provided only on the third diaphragm blade 23,
The third diaphragm blade 23 must be moved so as to cover the opening amount by the D filter 24.
The stroke of the diaphragm blade 23 in the height direction increases,
The size in the same direction becomes large, which hinders miniaturization.

The present invention has been made in view of the above problems, and provides a diaphragm device of an optical system capable of performing still operation and suppressing the stroke of the diaphragm blade in the height direction. The purpose is to provide.

[0014]

SUMMARY OF THE INVENTION The main invention of the present application is an optical system diaphragm apparatus for adjusting an aperture amount by moving diaphragm blades on a plane intersecting with an optical axis, which comprises a single density filter. A first diaphragm blade, a second diaphragm blade having no filter, and a third diaphragm blade having a filter having a density difference of at least two stages or more, the third diaphragm blade having a plurality of driving means. The present invention relates to a diaphragm device for an optical system, which is characterized in that three diaphragm blades are moved so as to make the displacement amount and the phase different from each other.

Here, a pair of driving means is provided, and the first driving means moves the first diaphragm blade and the second diaphragm blade, and the second driving means moves the third diaphragm blade. You may move.

Further, a cut is formed in the first diaphragm blade and the second diaphragm blade so as to face each other in the moving direction, and a single density filter is provided in the cut of the first diaphragm blade. You may be taken. Further, an opening for transmitting light may be formed in the third diaphragm blade, and a filter having a density difference of two or more steps may be attached so as to block a part of the opening. Further, a filter having a density difference of two stages or more provided in the third diaphragm blade may be provided on the same side in the moving direction as the single density filter of the first diaphragm blade.

Further, a partition plate is arranged in a flat casing having a small dimension in the optical axis direction, and the first diaphragm blade and the second diaphragm blade are arranged in one space with respect to the partition plate. The third diaphragm blade may be arranged in the other space with respect to the partition plate. Further, the filter provided on the third diaphragm blade and having a density difference of two or more stages may be formed by combining filters having a single density.

Next, preferred embodiments of the invention included in the present application will be listed below.

Aspect 1 In a diaphragm device for a photographing lens that restricts a diaphragm aperture by moving a diaphragm blade on a plane orthogonal to an optical axis, a first ND filter having no density difference is attached. A diaphragm blade, a second diaphragm blade without an ND filter attached, and a transmittance of at least 2
A third diaphragm blade to which one ND filter having a density difference of more than two stages is attached, and the displacement amounts and phases of the three diaphragm blades due to the rotation of the plurality of drive motors are different from each other. A unique photographic lens diaphragm device.

Aspect 2 A pair of drive motors attached to a case of the diaphragm device as a driving means for the three diaphragm blades,
An operating arm fixed to the rotary shaft of each drive motor, the operating arm of the first drive motor has two arms, and one connecting pin is provided at each of the distal ends of the two arms. And the operating arm of the second drive motor has one arm, and one connecting pin projects from the tip end of the one arm to connect the operating arms of the respective drive motors. The pins are slidably engaged with the connecting engagement holes of the corresponding diaphragm blades, and move so that the displacement amount and phase of the two diaphragm blades and one diaphragm blade due to the rotation of each drive motor are different. A diaphragm device for a photographing lens according to aspect 1, wherein:

Aspect 3 A first diaphragm blade to which one ND filter having no density difference is attached in order from the image pickup means side,
A second diaphragm blade to which an ND filter is not attached and one ND filter having a density difference of at least two levels or more are installed, or a density difference of at least two levels or more 3. A diaphragm device for a photographing lens according to aspect 1, further comprising: a third diaphragm blade having two ND filters attached thereto.

The diaphragm device for a photographing lens of the above-described aspect can be applied to both a diaphragm system using an ND filter having two or more densities and a still image system using a mechanical shutter. Moreover, even if there is no technology for manufacturing a 3-density or 2-density ND filter, which is difficult to manufacture, a 3-density ND filter system can be realized by sticking 1-density ND filters that can be produced by conventional manufacturing techniques.
In addition, two of the three diaphragm blades have N
By adopting a structure for mounting a D filter, N
It is not necessary to make the stroke of the specific diaphragm blade provided with the D filter larger than necessary, which makes it possible to reduce the dimension in the stroke direction and achieve miniaturization of the diaphragm device.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is an exploded view of a diaphragm device according to an embodiment of the present invention. The diaphragm device includes a flat housing 40 having a small dimension in the optical axis direction. A circular opening 41 is formed in the housing 40 so as to be located on the upper side thereof.
Is formed. The circular opening 41 serves as a light transmission hole. Further, a plurality of vertically extending projections 42 are formed on the inner surface of the housing 40, and a plurality of pins 43 are further implanted. Further, the housing 40 is provided with a plurality of arc-shaped openings 44 and 45 so as to be located on the lower side thereof.

A first diaphragm blade 47 is arranged in the housing 40. The diaphragm blade 47 has a V-shaped notch 48 so as to be opened downward, and the notch 4
8 to cover the ND filter (Neutral Den
A site filter) 49 is attached. In addition, a long hole 50 extending in the height direction is formed in the first diaphragm blade 47. These elongated holes 50 are adapted to engage with the pins 43 of the housing 40, thereby supporting the first diaphragm blade 47 slidably in the height direction.

An engaging hole 51 extending in the lateral direction is formed in the lower portion of the first diaphragm blade 47. This engagement hole 5
1 is one pin 5 of the drive arm 53 of the first motor 52
4 is received, whereby the diaphragm blade 47 is moved in the vertical direction in FIG.

A second diaphragm blade 58 is arranged in front of the first diaphragm blade 47. The diaphragm blade 58 is provided with a V-shaped notch 59 so as to be opened upward, and has a plurality of elongated holes 60 on its side portion. Further, engaging holes 61 extending in the lateral direction are formed on the lower end side, and these engaging holes 61 are adapted to receive another pin 62 of the drive arm 53 of the motor 52. Therefore, the rotation of the motor 52 causes the second diaphragm blade 58 to move in the direction opposite to that of the first diaphragm blade 47.

A partition plate 65 is arranged in front of the second diaphragm blade 58. The partition plate 65 has a circular opening 66 that defines the maximum opening amount, and has a ridge 67 on its surface. Further, a pin hole 68 is formed in the peripheral portion thereof so as to receive the pin 43 of the housing 40. Further, the partition plate 65 has openings 69, 7 below it.
0 is provided so that the pins 54 and 62 of the drive arm 53 of the motor 52 can escape.

A third diaphragm plate 73 is provided in front of the partition plate 65.
Are arranged. The diaphragm blade 73 is provided with an irregularly shaped opening 74, and an ND filter 75 having a density difference of two steps or more is attached so as to cover a substantially half region above the opening 74. In addition, a long hole 76 extending in the height direction is formed in the diaphragm blade 73, and an engaging hole 77 is formed in the lower portion of the diaphragm blade 73. The engagement hole 77 is engaged with the pin 80 of the drive arm 79 of the motor 78, so that the motor 78 can be moved in the vertical direction. Further, the third diaphragm blade 73 has cutouts 81 and 82 on its lower side and on both sides. These notches 81 and 82 are for allowing the pins 54 and 62 of the drive arm 53 of the motor 52 to escape.

A cover plate 85 is arranged in front of the third diaphragm blade 73. The cover plate 85 is provided with a long hole 86 that engages with the pin 43 of the housing 40, thereby covering the front side opening of the housing 40. Further, an opening 87 is formed in the central portion thereof. The bracket 90 is provided on the front side of the lid plate 85.
Is mounted and the bracket 78 holds the motor 78. And housing 4
A pair of screws 91 are screwed from the rear side so as to fix the 0, the lid plate 85, and the bracket 90 together.

As described above, in the diaphragm apparatus of the present embodiment, in the diaphragm apparatus of the photographing lens in which the diaphragm aperture is adjusted by moving the diaphragm blades on the surface orthogonal to the optical axis, the transmittance is at least two stages. N having the above density difference
A third diaphragm blade 73 to which a D filter 75 is attached;
A second diaphragm blade 58 to which a D filter is not attached;
A first diaphragm blade 47 to which an ND filter 49 having a transmittance different in density is attached, and two drive motors 52,
With the rotation of 78, the three diaphragm blades 47, 58, 7
It is characterized in that the displacement amount and the phase of 3 are different from each other.

The ND filter 49 provided on the first diaphragm blade 47 is an ND filter having the same transmittance as a whole and a transmittance of 33%. On the other hand, the ND filter 75 provided on the third diaphragm blade 73 has a density difference of two stages,
The upper part and the lower part have different transmittances. Ie ND
The lower part of the filter 75 has a transmittance of 33%, and the upper part has a transmittance of 10%.

The formation of the two-stage density difference of the ND filter 75 of the third diaphragm blade 73 is performed directly on a single transparent sheet.
A filter in which a thin film is formed so as to have a graded transmittance may be used. Alternatively, two filters having different transmittances may be combined. In particular, the latter method, in which two filters are combined, eliminates the need to apply a technique for manufacturing a two-density ND filter, which is difficult to manufacture, and reduces the cost of the ND filter 75. Planned. Here, as the ND filter 75 of the third diaphragm blade 73, it is possible to use a filter having a three-step density difference instead of the filter having a two-step density difference.

More specifically, as described above, the diaphragm device has three
It has two diaphragm blades 47, 58, 73. The ND filter 49 is attached to the diaphragm blade 47, and the ND filter 75 is attached to the diaphragm blade 73. A motor 52 is provided to drive the first diaphragm blade 47 and the second diaphragm blade 58, and another motor 78 is provided to drive the third diaphragm blade 73. Here, the ND filter 75 of the third diaphragm blade 73 has a transmittance of at least 2
The density difference is equal to or more than the level, whereas the ND filter 49 of the first diaphragm blade 47 has no density difference in transmittance.

Then, the notch 4 is formed in the diaphragm blades 47 and 58.
8 and 59 are formed, to which the third diaphragm blade 73 is formed.
An opening 74 is formed in the. In addition, diaphragm blades 47, 58, 7
3, elongated holes 50, 60, 76 extending in the vertical direction are formed and engage with the pins 43 of the housing 40. Further, these diaphragm blades 47, 58 and 73 are engaged holes 51 and 61, respectively.
Have 77.

A light transmission hole 41 and a guide pin 43 are formed in the case 40. The guide pin 43 has slits 50, 60, 7 of the three diaphragm blades 47, 58, 73.
6 by means of which the diaphragm blades 47, 5
8, 73 are supported slidably in the housing 40 in the vertical direction. On the other hand, the motors 52 and 78 are respectively the housing 40
And fixed to the bracket 90, these motors 5
It has drive arms 53 and 79 fixed to the rotating shafts of 2,78. The pins 54, 62, 80 at the tips of the drive arms 53, 79 are engaged with the engaging holes 51, 61, 77 of the corresponding diaphragm blades 47, 58, 73, respectively. Therefore, when the motors 52, 78 are driven and the operation arms 53, 79 rotate, the diaphragm blades 47, 58, 7
3 moves up and down. As a result, the shape of the aperture defined by the three diaphragm blades 47, 58, 73 changes, and the diaphragm function is exhibited.

Here, the operation arm 5 of the motors 52 and 78
3, 79 have arms, and the arms 53, 79 have motors 52, 78.
Since the length and direction from the center of rotation of are different,
Aperture blades 47, 58, 7 associated with driving the motors 52, 78
The displacement amount and the phase of 3 are different from each other. Therefore, the shape of the aperture opening and the region where the ND filters 49 and 75 cover the aperture opening 66 are sequentially changed as shown in FIGS. 2 and 3 as the drive motors 52 and 78 are driven.

FIG. 2A shows a first part of the upper side of the diaphragm opening 66.
The diaphragm blade 47 has the ND filter 49 applied thereto, and the diaphragm is almost fully opened.

FIG. 2B shows a notch 48 in the first diaphragm blade 47.
A diamond-shaped region defined by the notch 59 of the second diaphragm blade 58 is an opening, and this opening is entirely covered by the ND filter 49 of the first diaphragm blade 47.

FIG. 2C shows a cut 48 in the first diaphragm blade 47.
The amount of opening is determined by the rhombic region defined by and the notch 59 of the second diaphragm blade 58. Figure 2 shows the aperture
The same as B. However, here, the whole is covered with the ND filter 49 of the first diaphragm blade 47, and the upper half region is covered with the ND filter 75 of the third diaphragm blade 73 together with the ND filter 49.

In FIG. 3D, the aperture amount of the diaphragm is almost the same as in FIGS. 2B and 2C, but the third diaphragm blade 73 descends downward, and the entire area opened by this is covered by the ND filter 49. In addition, the entire area of the opening is covered with the ND filter 75.

In FIG. 3E, the opening amount is shown in FIGS. 2B, C and 3D.
But the entire area of the opening is covered by the ND filter 49, and further the entire area of the opening is completely covered by the dense area above the ND filter 75. The transmission amount of is greatly suppressed by the ND filters 49 and 75.

FIG. 3F shows a case where the first motor 52 is largely rotated, and thereby the first diaphragm blade 47 and the second diaphragm blade 58 are largely moved in the opposite directions. It shows a state in which the diaphragm aperture defined by 48 and 59 no longer exists. This state is a fully closed state, in which light is completely blocked. Therefore, the mechanical shutter operation is achieved by utilizing this fully closed state.

[0043]

The main invention of the present application is, in a diaphragm apparatus of an optical system for adjusting an aperture amount by moving diaphragm blades on a plane intersecting with an optical axis, a first diaphragm having a single density filter. The blade includes a blade, a second diaphragm blade having no filter, and a third diaphragm blade having a filter whose transmittance has a density difference of at least two stages or more. The displacement amount and the phase are moved so as to be different from each other.

Therefore, according to the diaphragm device of such an optical system, the mechanical shutter function is achieved by the combination of the operations of the first diaphragm blade and the second diaphragm blade. Further, since the first diaphragm blade and the third diaphragm blade are each provided with a filter and can be driven independently, it is not necessary to unnecessarily increase the stroke of the diaphragm blade having the filter, and the size in the moving direction is suppressed to reduce the size. An improved diaphragm device will be provided.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a diaphragm device of an optical system according to a first embodiment.

FIG. 2 is a front view showing an operation of adjusting an aperture amount of a diaphragm and adjusting a light transmission amount by a filter.

FIG. 3 is a front view showing an operation of adjusting an aperture amount of a diaphragm and adjusting a light transmission amount by a filter.

FIG. 4 is an exploded perspective view of a main part of a conventional diaphragm device.

FIG. 5 is an exploded perspective view of a main part of another conventional diaphragm device.

[Explanation of reference symbols] 40 ... Casing, 41 ... Circular opening, 42 ...
3 ... pin, 44, 45 ... opening, 47 ... first diaphragm blade, 48 ... notch, 49 ... ND filter, 50 ...
... elongated hole, 51 ... engaging hole, 52 ... motor, 53 ... drive arm, 54 ... pin, 58 ... second diaphragm blade, 5
9 ... Notch, 60 ... Long hole, 61 ... Engagement hole, 62 ...
Pins, 65, partition plates, 66, circular openings, 67
・ ・ ・ Ridge, 68 ・ ・ ・ Pin hole, 69, 70 ・ ・ ・ Opening, 73
3rd diaphragm blade, 74 opening, 75 ND filter, 76 long hole, 77 engaging hole, 78 motor, 79 driving arm, 80 pin, 81, 82 ...
Notch, 85, lid plate, 86, oblong hole, 87, opening, 90, bracket, 91, screw

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) G03B 9/24 G03B 9/24 11/00 11/00

Claims (7)

[Claims] 1. A diaphragm apparatus for an optical system, wherein a diaphragm blade is moved on a plane intersecting an optical axis to adjust an aperture amount, a first diaphragm blade having a single density filter and no filter. A second diaphragm blade; and a third diaphragm blade having a filter whose transmittance has a density difference of at least two stages or more, and a displacement amount and a phase of the three diaphragm blades by a plurality of driving means. A diaphragm device for an optical system, characterized in that it is moved so as to be different. 2. A pair of driving means, wherein the first driving means moves the first diaphragm blade and the second diaphragm blade, and the second driving means moves the third diaphragm blade. The diaphragm device for an optical system according to claim 1, wherein the diaphragm device moves. 3. A notch is formed in the first diaphragm blade and the second diaphragm blade so as to face each other in the moving direction, and a single density filter is provided in the notch of the first diaphragm blade. The diaphragm device for an optical system according to claim 1, wherein the diaphragm device is provided. 4. The third aperture blade is formed with an opening through which light passes, and a filter having a density difference of two or more steps is attached so as to block a part of the opening. A diaphragm device for the optical system according to. 5. A filter having a density difference of two stages or more provided on the third diaphragm blade is provided on the same side as a single density filter of the first diaphragm blade in the moving direction. The diaphragm device for an optical system according to claim 1. 6. A partition plate is arranged in a flat casing having a small dimension in the optical axis direction, and the first diaphragm blade and the second diaphragm blade are arranged in one space with respect to the partition plate. The diaphragm device for an optical system according to claim 1, wherein the third diaphragm blade is arranged in the other space with respect to the partition plate. 7. The filter according to claim 1, wherein the filter having a density difference of two stages or more provided on the third diaphragm blade is constituted by a combination of filters having a single density. Optical system diaphragm device.