JP2018163246A - Blade driving device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blade driving device that prevents a ghost.SOLUTION: A blade driving device comprises: an opening formation member which forms a fixed opening for allowing light to pass; a plurality of diaphragm blades 104 which move to and away from the fixed opening to form a diaphragm opening; a power transmission member which transmits driving force to the plurality of diaphragm blades 104 through rotating operation; and a plurality of engagement parts which are arranged at the power transmission member and engage engaged parts that the plurality of diaphragm blades 104, the plurality of engagement parts being arranged based upon positions, in the fixed opening, of the diaphragm blades 104 forming a diaphragm opening formed to differ in opening center from the fixed opening.SELECTED DRAWING: Figure 2

Description

The present invention relates to a light-shielding structure of a photographing lens, and more particularly to a light-shielding structure of a photographing lens that removes a ghost image due to incidence of harmful light rays from outside the photographing angle of view.

  In a conventional camera, for example, a first lens group, a second lens group, a third lens group, and a fourth lens group are arranged in this order in a lens barrel, and between the third lens group and the fourth lens group. There is a diaphragm in which the light passing through each lens group and the diaphragm is imaged on an imaging surface such as a CCD.

  By the way, when extremely strong light such as the sun or illumination light enters from outside the shooting angle of view of a conventional photographic lens, the light is reflected from the aperture opening end face or the inner surface of the lens barrel and reaches the imaging surface. There is a problem that occurs. In order to prevent harmful rays that cause such ghosts from entering the imaging surface, conventional imaging lenses have a light blocking structure to reduce the aperture diameter of the aperture and lens frame, and to block harmful light. I do.

JP-A-8-234072 JP-A-8-334725

However, if a light shielding structure is provided in the optical path as in the photographing lens disclosed in Patent Document 1, the effective area of the lens when the aperture is opened is affected. Further, as with the photographing lens disclosed in Patent Document 2, there is a problem that if the aperture diameter is made small, a part of the light passing area necessary for photographing is shielded widely. This unnecessarily reduces the effective aperture of the lens, and there is a problem that the F-number when the aperture is opened is increased.

The blade driving device according to the present invention is made in view of such circumstances,
An opening forming member having a fixed opening through which light passes;
A plurality of diaphragm blades entering and exiting the fixed opening;
A power transmission member for applying a driving force to the plurality of diaphragm blades,
The center of the aperture opening formed by the plurality of aperture blades is located between the center of the fixed aperture and the opening edge of the fixed aperture.

  According to the present invention, it is possible to prevent the occurrence of ghosts caused by harmful rays incident from outside the shooting angle of view without reducing the effective aperture.

The disassembled perspective view of the blade | wing drive device which concerns on Embodiment 1 of this invention. FIG. 3 is a front view showing a change in the aperture opening of the first embodiment. 1 is a cross-sectional view 1 of a photographic lens according to Embodiment 1 of the present invention. Sectional drawing 2 of the imaging lens which concerns on Embodiment 1 of this invention. Sectional drawing 3 of the imaging lens which concerns on Embodiment 1 of this invention. The disassembled perspective view of the blade | wing drive device which concerns on Embodiment 2 of this invention. FIG. 6 is a front view showing a change in the aperture opening of the second embodiment. The front view which shows the change of the aperture opening of Embodiment 2 (without a cover). The disassembled perspective view of the blade | wing drive device which concerns on Embodiment 3 of this invention. FIG. 9 is a front view showing a change in the aperture opening of the third embodiment. The front view which shows the change of the aperture opening of Embodiment 3 (without a cover). The disassembled perspective view of the blade drive device which concerns on Embodiment 4 of this invention. FIG. 10 is a front view showing a change in the aperture opening of the fourth embodiment. The front view which shows the change of the aperture opening of Embodiment 4 (without a cover). Schematic of the optical apparatus carrying the blade drive device of Embodiments 1-4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 shows an exploded perspective view of a diaphragm device as a blade driving device which is an example of the blade driving device according to the first embodiment of the present invention. FIG. 2 shows a state where the cover 106 shown in FIG. 1 is removed. Furthermore, FIG. 2 shows the process of changing from full aperture to closed close in the order of (A) ⇒ (B) ⇒ (C) ⇒ (D) ⇒ (E). In these drawings, the longitudinal direction along the opening surface of the diaphragm device, and the vertical direction when the diaphragm device is incorporated in an optical device, corresponds to the “direction perpendicular to the light passing direction”. In the following description, it is referred to as an optical axis orthogonal direction. Moreover, the left-right direction (short direction along the opening surface) of the diaphragm device in these drawings is referred to as the width direction.

  In these drawings, the base plate 102 as an opening forming member is formed with a fixed opening 102a through which light passes. The ground plane 102 is manufactured by press working or resin molding. A diaphragm driving unit 101 is attached to a position away from the fixed opening 102a on the outer surface (surface on one side in the optical axis direction) of the base plate 102. The aperture drive unit 101 includes, for example, a rotor magnet (not shown), a drive lever 103 (power transmission member) that rotates integrally with the rotor magnet, and a coil (not shown) that generates a magnetic force that is energized to rotate the rotor magnet. This is an electromagnetic drive motor configured. Further, a stepping motor may be used.

  The drive lever 103 has blade drive pins 103i and 103j. The drive lever 103 rotates within a predetermined angular range around an axis (rotation center 103a) positioned downward from the fixed opening 102a. The drive lever 103 is formed by resin molding or the like.

  The drive lever 103 has blade drive pins 103i and 103j as transmission parts for driving the diaphragm blades 104 to 105 at the front ends on both sides in the width direction of the base plate 102 across the position of the rotation center 103a. The blade driving pin 103 i is engaged with the diaphragm blade 104. The blade driving pin 103j is engaged with the diaphragm blade 105. By rotating the drive lever 103, the diaphragm blade 104 and the diaphragm blade 105 enter and exit into the fixed opening 102a of the main plate 102 to form the diaphragm opening and change its size (diameter).

  The diaphragm blades 104 to 105 are formed by press molding or resin molding.

  The diaphragm blade 104 and the diaphragm blade 105 move in a direction orthogonal to the light passage opening so as to sandwich the fixed opening 102b. Details of each diaphragm blade will be described below. The aperture blade 104 is engaged with the blade drive pin 103i of the drive lever 103 at a drive hole 104i that is an engagement portion. In addition, guide long holes 104b and 104c as engaging portions formed so as to extend in the direction perpendicular to the optical axis of the diaphragm blade 104 have guide pins 102b as guide portions (guide shaft portions) formed in the base plate 102. , 102c are slidably engaged. When the drive lever 103 is rotated within the predetermined angle range described above, the diaphragm blade 104 receives a driving force from the blade drive pin 103i at the drive hole portion 104i, and the guide long hole portions 104b and 104c are driven by the guide pins 102b and 102c. It is driven in the direction orthogonal to the optical axis while being guided.

The aperture blade 104 is formed with a long hole portion 104d for avoiding interference with the guide pin 102d. By making the guide pin 102d penetrate the elongated hole portion 104d, that is, by extending the diaphragm blade 104 in the width direction of the main plate 102 beyond the guide pin 102d, the shape of the diaphragm blade 104 is increased in strength. The shape can be secured, and the guide pins 102d can be efficiently disposed on the main plate 102. Further, by forming the elongated hole portion 104d in the diaphragm blade 104, the diaphragm blade 104 can be reduced in weight, which is effective for the shutter operation.

  The aperture blade 105 is engaged with the blade drive pin 103j of the drive lever 103 at a drive hole 105j which is an engagement portion. Further, guide long holes 105d and 105e as engaging portions formed so as to extend in the direction perpendicular to the optical axis in the diaphragm blade 105 have guide pins 102d as guide portions (guide shaft portions) formed in the base plate 102. , 102e are slidably engaged. When the driving lever 103 is rotated within the above-mentioned predetermined angle range, the diaphragm blade 105 receives driving force from the blade driving pin 103j at the driving hole portion 105j, and the guide long hole portions 105d and 105e are driven by the guide pins 102d and 102e. It is driven in the direction orthogonal to the optical axis while being guided.

The aperture blade 105 is formed with a long hole portion 105b for avoiding interference with the guide pin 102b. By making the guide pin 102b penetrate the elongated hole portion 105b, that is, by extending the diaphragm blade 105 in the width direction of the main plate 102 beyond the guide pin 102b, the shape of the diaphragm blade 105 is increased in strength. The shape can be secured, and the guide pins 102b can be efficiently arranged on the main plate 102. Further, by forming the long hole portion 105b in the diaphragm blade 105, the diaphragm blade 105 can be reduced in weight, which is effective for the shutter operation.

  In the first embodiment, the diaphragm blades are engaged with the blade driving pins 103i and 103j of the drive lever 103 one by one, but a plurality of the blades may be engaged simultaneously. Further, in the first embodiment, the example in which the diaphragm blades move straight is described. However, the movement of the diaphragm blades may be configured to go in and out of the fixed opening 102a by movements such as straight movement, rocking, and rotation. The guide for the diaphragm blades is not limited to the method described above. For example, the guide long hole portions 104b and 104c of the diaphragm blade 104 may be formed by bending so that the diaphragm blade 104 moves back and forth with respect to the fixed opening 102a while swinging. , 102c, etc., may be moved back and forth to the fixed opening 102a. Alternatively, the number of blade drive pins provided on the drive lever may be increased, and different types of diaphragm blades may be engaged with the respective drive pins to form a diaphragm opening.

  The cover 106 is a cover attached to the base plate 102 so as to form a space in which the diaphragm blades 104 and 105 are accommodated and moved between the cover 106 and the base plate 102. The cover 106 has an opening 106 a corresponding to the fixed opening 102 a formed in the main plate 102. Moreover, it has the opening or recessed part corresponding to the guide pins 102b-e. The cover 106 is formed by pressing, resin molding, or the like. A rail (not shown) is formed on the inner surface of the cover 106 (the surface on the ground plane side) in order to reduce sliding resistance with the diaphragm blades 104 and 105. In the present embodiment, as shown in FIG. 1, the outer surface of the cover 106 is flat. However, the rail 106 may be formed by bending the cover 106 formed of a flat plate so as to protrude toward the base plate 102 side.

  In the present embodiment, the drive lever 103 has different arm lengths on the left and right. The length of the arm means the length of the blade driving pin 103j from the rotation center 103a and the length of the blade driving pin 103i from the rotation center 103a. Since the length of each arm of the drive lever 103 is different, when the drive lever 103a is rotated to drive the diaphragm blade, the speed and distance at which each diaphragm blade enters the fixed opening 102a is different. Since the arm on the blade driving pin 103j side is longer, the moving speed of the diaphragm blade 105 is faster.

  Next, changes in the aperture of the present embodiment will be described with reference to FIG. In FIG. 2A, the aperture blade 104 and the aperture blade 105 are in a position retracted from the fixed opening 102 a of the main plate 102.

  FIG. 2B shows a state where only the diaphragm blade 105 has entered the fixed opening 102 a of the main plate 102. Since the length of each arm of the drive lever 103 is different, the diaphragm blade 105 enters the fixed opening 102a first. Here, FIG. 3 and FIG. 4 are cross-sectional views of the photographing lens when the blade driving device is in the state of FIG. As described above, in the diaphragm blade according to the present embodiment, only the diaphragm blade 105 enters the fixed opening 102a to form the diaphragm opening. In this case, the center of the diaphragm opening formed by the diaphragm blade 105 is formed. P deviates upward from the center of the fixed opening 102a. The smaller the aperture opening by the aperture blade 105, the more the center P of the aperture opening is displaced from the center of the fixed aperture 102a.

  FIG. 3 shows light that causes a ghost in the first lens group 1. For example, the sunlight L is reflected from the inner surface of the lens barrel and travels toward the image sensor 107 along the locus shown in the figure. Although such reflection on the inner surface of the lens barrel has caused ghosting, in the blade driving device of this embodiment, only the lower side of the optical path where the reflected light from the sunlight L concentrates can be blocked by the diaphragm blade 105. Therefore, it is possible to prevent a ghost while ensuring the area of the aperture opening.

FIG. 4 shows light that causes ghost in the first lens group 1. For example, part of the sunlight L is totally reflected by the lens surface and travels toward the image sensor 107 along the locus shown. Such multiple reflections have caused ghosting, but in the blade drive device of this embodiment, it is possible to block only the lower side of the optical path where the light due to total reflection of the sunlight rays L is concentrated by the diaphragm blades 105. Therefore, it is possible to prevent ghost while securing the area of the aperture opening.

  At this time, since it is not necessary to shield the upper side of the optical path, it is possible to prevent the occurrence of a ghost with the minimum necessary light shielding. Furthermore, in this embodiment, since the structure can be controlled to the state shown in FIG. 2B in a shooting environment with strong light, in the normal shooting environment, the effective area of the lens when the aperture is open. There is no impact on That is, when adjusting the light amount in the normal aperture operation, a part of the aperture opening is made to enter the fixed aperture 102a in advance, so that it is possible to obtain a predetermined light amount when it is desired to obtain a predetermined aperture value. It is possible to easily form a structure that prevents light that causes ghosts from entering the image sensor surface simply by performing a diaphragm operation toward the aperture.

  Returning to FIG. 2, changes in the aperture opening will be described. 2C and 2D show the state of the intermediate diaphragm. In FIG. 2C, the center P of the aperture opening formed by the aperture blades 104 and 105 is shifted from the center O of the fixed aperture 102a of the main plate 102 in the direction of the edge of the fixed aperture 102a. 2D, the aperture opening formed by the aperture blade 104 and the aperture blade 105 is formed at a position between the center O of the fixed aperture 102a of the base plate 102 and the edge of the fixed aperture 102a. The center of the aperture opening P in (C) is displaced in the direction of the edge of the fixed opening 102a. 2C and FIG. 2D, the position is shifted upward from the fixed opening 102a. In other words, the aperture of the photographing lens is formed at a position away from the lens center O.

  2B, similarly to FIGS. 2C and 2D, the center P of the aperture opening formed by the aperture blade 104 and the aperture blade 105 is from the center O of the fixed aperture 102a of the main plate 102. The position is shifted. That is, it is closer to the center O of the fixed opening 102a than in FIG. 2C, and the center P of the stop opening gradually shifts toward the edge of the fixed opening 102a as the stop opening is reduced.

  FIG. 5 is a cross-sectional view of the photographing lens when the blade driving device is in the state of FIG. The light illustrated in FIG. 5 indicates light reflected from the surface of the image sensor 107. Unlike the lens, it is difficult to apply an anti-reflection coating on the imaging element surface. Reflection of light on the image pickup element surface is a factor of multiple reflection in the photographing lens, and is a factor of generating ghost.

In the blade driving device of this embodiment, the aperture opening is formed only in one direction with respect to the center O of the lens. The light incident on the aperture opening is reflected by the image sensor surface, and the reflected light returns to the opposite side with respect to the lens center O. At this time, since the reflected light reaches the light shielding portion formed by the diaphragm blade 105 of the blade driving device, the reflected light is blocked.

  Accordingly, an antireflection film is formed on the surface of the diaphragm blade 105 on the image pickup element side. For example, a black paint is used. However, the present invention is not limited thereto, and when the diaphragm blade 105 is formed of resin, the resin itself is reflected. It may be the structure which can prevent. In the blade driving device in which the center of the lens and the center P of the aperture opening are on the same axis, the reflected light cannot be blocked by the aperture blade. In the blade driving device of this embodiment, multiple reflections (particularly, reflection of light reaching the imaging element surface) in the lens can be prevented, and ghosting can be prevented. The optical apparatus using the blade driving device of the present embodiment can prevent a ghost that occurs in a strong light environment, and thus exerts a great effect in fields such as a surveillance camera and an in-vehicle camera used outdoors.

  FIG. 2E is a view when the aperture opening is completely closed. The diaphragm device of this embodiment can change the diaphragm aperture diameter by rotating the drive lever 103 as described above, and can completely close (close) the diaphragm aperture. For this reason, the aperture device of the present embodiment can also perform a shutter operation. That is, the aperture device of this embodiment can also be used as an aperture shutter device. In addition, completely closing the aperture opening can prevent the image sensor from being exposed to light when the image pickup apparatus is not used, which is also useful for protecting the image sensor.

  In the first embodiment, an optical filter (for example, an ND filter or an IR cut filter) may be attached to the diaphragm blade 104 or the diaphragm blade 105 to adjust the light amount. It is also possible to provide a drive unit different from the aperture drive unit 101 and drive the optical filter to adjust the light quantity.

  For example, when an IR cut filter is used, an IR cut filter is used in combination in an environment where there is a large amount of predetermined light such as infrared light or visible light during the daytime, and an environment where there is little predetermined light such as visible light at night or indoors. In this case, the IR cut filter may be used so as to retract from the optical axis. The IR cut filter may be driven by a drive unit different from the aperture drive unit 101. However, the IR cut filter may be driven in conjunction with a part of the aperture blades 104, for example, in an environment with a large amount of light. You may make it enter into an optical axis only when a diaphragm opening is smaller than a predetermined opening diameter. As an example, when the aperture opening is the maximum aperture, the filter does not enter the fixed aperture 102a, but the filter enters the fixed aperture 102a in conjunction with the aperture opening being formed by the aperture blade. You may comprise.

  The forward / backward movement of the filter may be switched based on the amount of ambient light. Other methods include IR cut filter and ND filter only when it is determined, for example, during the day based on the time acquired from the clock built in the imaging device or from an external device. You may switch back and forth. Further, advance / retreat may be controlled according to the diameter of the aperture. Further, the user may manually switch the advance / retreat of the filter. Note that, depending on the usage environment, if the amount of light incident on predetermined light such as infrared light or visible light is large due to the influence of a light source other than sunlight even at night, the filter may be used only at that timing.

  The blade driving device of the present embodiment can prevent the occurrence of ghosts in various imaging lenses, but is particularly effective for a single focus lens. In the blade driving device of the first embodiment, the number of lenses arranged between the image sensor and the diaphragm blades is such that the light reflected by the image sensor earlier can be blocked by the diaphragm blades. Compared to the zoom lens, the single focus lens can obtain a greater effect because the number of lenses disposed between the blade driving device and the image sensor is small.

  In the blade driving device according to the present embodiment, in the process of changing from the full aperture to the small aperture, the ghost is preferentially shielded from the lower side of the optical path where harmful light that causes the ghost is concentrated, thereby preventing the ghost. it can. In addition, since it is not necessary to arrange a light blocking member that blocks the optical path, there is no effect on the effective area of the lens when the aperture is opened. In addition, since the aperture diameter is not reduced from the entire circumference, but is shielded from the lower side of the optical path where harmful light is collected, it is possible to prevent the occurrence of ghosts with the minimum necessary light shielding.

  In addition, in an imaging lens configured by overlapping lenses, sunlight or the like is reflected multiple times and becomes a ghost. However, in the present invention, since the aperture is located between the center of the lens and the edge of the aperture, Etc. can be blocked by the diaphragm blades. Therefore, it is possible to prevent ghosts due to multiple reflections.

<Embodiment 2>
In FIG. 6, the disassembled perspective view of the aperture_diaphragm | restriction apparatus as a blade drive device which is an example of the blade drive device which is Embodiment 2 of this invention is shown. 7 and 8 show the process of changing from the full aperture to the small aperture in the order of (A) → (B) → (C).

  In FIG. 6, the base member 202 has a light passage opening 202a at the center. The base member 202 has shafts 202b to 202h that engage with cam grooves (or long grooves) 204b2 to 204h2 of a diaphragm blade 204 described later. The base member 202 is formed by resin molding or the like. The drive unit 201 is attached to the base member 202. The driving unit 201 uses, for example, a stepping motor, a galvano motor, or the like. A pinion 203 is attached to the rotation shaft 201 a of the drive unit 201.

  The drive ring 205 has a through hole that constitutes at least a part of the light passage path, and is formed from an annular sheet-like member (endless ring-like member) that surrounds a path through which light passes (light passage path). It rotates around the light passage path. A diaphragm blade 204 described later is engaged with the drive ring 205. That is, since the drive ring 205 is configured to be interlocked so that the diaphragm blade 204 enters and exits the light passage path as the drive ring 205 rotates, a member for driving the diaphragm blade 204 ( Power transmission member). The drive ring 205 includes a light passage opening 205a, shafts (engagement portions) 205b to 205h that engage with holes (engaged portions) 204b1 to 204h1 of the diaphragm blade 204, and a driven portion 205i.

  The drive ring 205 is formed by resin molding or the like. For example, it forms by pressing a resin film (PET sheet material etc.). When press working is possible, since the shape accuracy can be formed higher than the shape accuracy of resin molding, it is possible to increase the drawing accuracy.

  As the thickness of the resin film, a material having a thickness of 0.03 mm to 0.30 mm can be used. By reducing the thickness as much as possible, the inertia during rotation can be reduced, and the diaphragm device can be operated at high speed. The drive ring 205 is supported by the base member 202 and the cover member 206 so as to be optimally movable in both the thrust direction and the radial direction, thereby minimizing deformation of the drive ring 205 even when the thickness is reduced.

  When the drive ring is made of a resin film, the shafts 205b to 205h are integrally formed by bonding, welding, outsert molding, or the like, made by resin molding. Or what was formed with the metal pin may be integrated by adhesion, welding, caulking, or the like.

  The drive ring 205 is preferably made of a material that has been surface-treated on one or both sides. Examples of the surface treatment include sliding coating, antistatic treatment, and antireflection treatment. By sliding coating, friction with the base member 202, which is a component that slides with the drive ring, diaphragm blades 204 and a cover member 206, which will be described later, can be reduced, and power-saving operation is possible. In addition, by performing antireflection treatment, it is possible to suppress the reflection of light entering the light amount adjusting device and prevent the occurrence of ghost, flare, etc. when the light amount adjusting device is incorporated in the lens barrel. it can.

  Further, the drive ring 205 has a gear portion which is a driven portion 205i. The driven portion 205 i is engaged with the pinion 203. The rotational force generated in the drive unit 201 is transmitted from the pinion 203 to the driven unit 205i, and the drive ring 205 rotates. In the meshing of the gear portion 205i of the drive ring 205 and the gear of the pinion 203, the gear portion 205i is thin and the meshing area of the gear is small, so that the meshing sound between the gears is small. Further, since the mass difference between the pinion 203 and the drive ring 205 is large, even if there is a backlash between the pinion 203 and the gear portion 205i, the gear meshing sound, the reversing sound, etc. are reduced.

  Moreover, it has the light-shielding part 205m, and plays the role of a sensor by going in and out of the slit of the photo interrupter 208. Used for initialization of the light quantity control device.

  As shown in FIG. 6, the diaphragm blade 204 has a hole 204b1 (to h1) and a cam groove (or long groove) 204b2 (to h2). The diaphragm blades 204 are created by pressing a resin film (PET sheet material or the like).

  The cover member 206 has a light passage opening 206a. The cover member 206 is connected to the base member 202 mainly by hooking or screwing (not shown). The drive ring 205 and the diaphragm blade 204 are driven in the space formed by the base member 202 and the cover member 206.

  Here, the movement of the diaphragm blades 204 of the second embodiment will be described. The cam groove (or long groove) 204b2 of the diaphragm blade 204 engages with the shaft 202b of the base member. The hole 204b1 of the diaphragm blade 204 engages with the shaft 205b of the drive ring 205. When the pinion 203 rotates, a force is applied to the driven part 205i of the drive ring 205, and the drive ring 205 rotates. When the drive ring 205 rotates, the diaphragm blade 204 rotates together with the drive ring 205 because the shaft 205b of the drive ring 205 and the hole 204b1 of the diaphragm blade 204 are engaged. At this time, since the cam groove (or long groove) 204b2 of the diaphragm blade 204 is engaged with the shaft 202b of the base member, the diaphragm blade 204 rotates around the shaft 202b while being guided by the cam groove (or long groove) 204b2. . By rotating the plurality of aperture blades 204 as described above, the aperture blades 204 can enter and exit the light passage opening 202a of the base member 202, and the aperture shape can be adjusted.

  Furthermore, in the second embodiment, the cam grooves (or long grooves) 204b2 to 204h2 of the diaphragm blades 204 have different shapes as appropriate. By changing the shape of the cam groove, the speed at which each diaphragm blade 204 enters the light passage opening 202a can be changed.

  FIG. 7 shows the aperture shape viewed from the cover member 206 side. In the process of changing to (A) full aperture, (B) intermediate aperture, and (C) minimum aperture, the aperture blade 204 has a cam groove 204b2 (~ 204h2) along the axis (regulator) 202b (~ 204h) of the base member. Move. Although not shown, also in the second embodiment, similarly to the first embodiment, only the lower side of the light passage opening 202a can be temporarily shielded by the diaphragm blades 204 (the same state as in FIG. 2B). . The light passage opening as the device may be the fixed opening 202a of the base member 202 or the light passage opening 206a of the cover member 206. In the present embodiment, the fixed opening 202a and the light passage opening 206a are the same. It is a size. The light passage opening 206a of the cover member 206 may be a light passage opening as the entire blade driving device.

  8 is a view in which the cover member 206 is removed from FIG. The axes 205b to 205h of the drive ring 205 of Embodiment 2 are arranged at different angles with respect to the center of the light passage opening 202a. This is because, when the aperture shape of the minimum aperture is formed in FIG. 8C, all the arc lengths per aperture blade are arranged to be the same length. Thereby, even at the minimum aperture, the aperture shape becomes a shape close to a regular polygon as many as the number of blades, and natural image quality can be obtained even with respect to blur where the aperture shape appears remarkably.

  The angle between the shafts of the drive ring is a shaft provided on the power transmission member engaged with the aperture of the aperture blade that moves the blade tip toward the lower side of the optical path of the fixed aperture in the process of changing from the aperture opening to the minimum aperture. If the angle between them is smaller than the angle between the shafts provided on the power transmission member with which the aperture of the aperture blade that moves toward the upper optical path of the fixed aperture engages, the minimum aperture Since the aperture shape at that time approaches a regular polygon as many as the number of blades, it is also advantageous for blurring where the aperture shape appears remarkably.

  Specifically, in FIG. 8, in the process of narrowing the aperture opening from FIG. 8A to FIG. 8C, the position of the aperture opening (center of the aperture opening) moves upward. The leading end side of the diaphragm blade 204 is disposed so as to face the counterclockwise direction. At this time, with respect to the angle of the shaft 205e and the shaft 205f located on the left side that is the upper side in which the aperture opening moves and the front end of the aperture blade faces, the shaft 205b and the shaft 205f The angle between the shaft 205f and the shaft 205g and the angle between the shaft 205g and the shaft 205h are gradually changed so that the angle between the shafts 205h increases.

  In the present embodiment, the angle between the shaft 205e and the shaft 205f and the angle between the shaft 205e and the shaft 205d are substantially equal. However, the angle is appropriately changed depending on the number and shape of the diaphragm blades 204. The In any case, when viewed as the whole of the shafts 205b to h of the diaphragm blade 204 or the drive ring 205, it is on the upper side that is the direction in which the diaphragm opening moves and on the left side that is the direction in which the tip of the diaphragm blade faces. By making the angle between the shafts smaller, the aperture shape at the time of small aperture can be made closer to a regular polygon as many as the number of blades.

  In the present embodiment, the rotation angle of the diaphragm blades 204 engaged with the shafts having a small angle between the shafts, that is, the diaphragm blades 204 engaged with the shafts 205e and 205f is large. The diaphragm blade 204 is formed so as to be larger than the rotation angle of the diaphragm blade 204 engaged with the shaft, that is, the diaphragm blade 204 engaged with the shaft 205b and the shaft 205h. That is, in each state of FIGS. 8A to 8C, the diaphragm blades 204 engaged with the shafts 202 b to 202 h have different rotation angles in a predetermined amount of rotation operation of the drive ring 205. The cam grooves 204b2 to 204h2 are formed so that the abutting positions where the shafts 202b to 202h actually abut against the cam grooves 204b2 to 204h2 abut against the center of the fixed opening 202a at different angles. It has become.

  In the blade driving device of the second embodiment, as in the first embodiment, the center of the aperture opening gradually moves away from the center of the fixed aperture 202a in the process of changing from open to minimum aperture. That is, even when the blade driving device of the second embodiment is used, harmful light can be shielded to the minimum necessary as described with reference to FIGS. 3, 4, and 5, and ghosting can be prevented. It is.

  In the present embodiment, the shafts 205b to 205h of the drive ring 205 are arranged at different angles around the light passage opening 202a in consideration of the diaphragm shape at the time of the minimum diaphragm, but the same with respect to the light passage opening 202a. Even when the shafts 205b to 205h are arranged at angles, the center of the aperture opening gradually moves away from the center of the fixed aperture 202a in the process of changing from open to small aperture, which is effective for preventing ghosts.

  In the present embodiment, the shape of the diaphragm blades 204 is small at the upper and left diaphragm blades of the fixed opening 202a, that is, the diaphragm blades engaged with the shaft 205e and the shaft 205f, whereas the diaphragm blades at the lower and right sides of the fixed opening 202a. The aperture blade 204b that engages with the shaft 205b is formed to be large.

<Embodiment 3>
In FIG. 9, the disassembled perspective view of the aperture_diaphragm | restriction apparatus as a blade drive device which is an example of the blade drive device which is Embodiment 3 of this invention is shown. 10 and 11 show the process of changing from full aperture to small aperture in the order of (A) ⇒ (B) ⇒ (C).

  The base member 302 has a light passage opening 302a at the center. The base member 302 is formed by resin molding or the like. The drive unit 301 is attached to the base member 302. The drive unit 301 uses, for example, a stepping motor, a galvano motor, or the like. A pinion 303 is attached to the rotation shaft 301 a of the drive unit 301.

  The drive ring 305 has a through hole that constitutes at least a part of the light passage path, and is formed from an annular sheet-like member (endless ring-like member) that surrounds a path through which light passes (light passage path). It rotates around the light passage path. A diaphragm blade 304 described later is engaged with the drive ring 305. That is, the drive ring 305 is configured such that the diaphragm blade 304 enters and exits the light passage path in conjunction with the rotation of the drive ring 305, and thus a member (power transmission member) for driving the diaphragm blade 304 ) This drive ring 305 has holes 305b to 305h that engage with light passing openings 305a that are through holes, shafts 304b1 to 304h1 of the diaphragm blade 304, and a driven portion 305i.

  The drive ring 305 is created by resin molding or the like. Further, for example, it may be created by pressing a resin film (PET sheet material or the like). When press working can be performed, the shape accuracy can be formed with higher accuracy than the shape accuracy of resin molding, so that the drawing accuracy can be high.

  As the thickness of the resin film, a material having a thickness of 0.03 mm to 0.30 mm can be used. By reducing the thickness as much as possible, the inertia during rotation can be reduced, and the diaphragm device can be operated at high speed. The drive ring 305 is supported by the base member 302 and the cover member 306 so as to be optimally movable in both the thrust direction and the radial direction, so that deformation of the drive ring 305 is minimized even if the thickness is reduced.

  The drive ring 305 may be made of a material that is surface-treated on one side or both sides. Examples of the surface treatment include sliding coating, antistatic treatment, and antireflection treatment. By sliding coating, friction with the base member 302, which is a part that slides with the drive ring, a diaphragm blade 304 and a cover member 306, which will be described later, can be reduced, and operation with low power consumption becomes possible. In addition, by performing antireflection treatment, it is possible to suppress the reflection of light entering the light amount adjusting device and prevent the occurrence of ghost, flare, etc. when the light amount adjusting device is incorporated in the lens barrel. it can.

  Further, the drive ring 305 has a gear portion which is a driven portion 305i. The driven portion 305 i meshes with the pinion 303. The rotational force generated in the drive unit 301 is transmitted from the pinion 303 to the driven unit 305i, and the drive ring 305 rotates. In the meshing of the gear portion 305i of the drive ring 305 and the gear of the pinion 303, the gear portion 305i is thin and the meshing area of the gear is small, so that the meshing sound between the gears is small. Further, since the mass difference between the pinion 303 and the drive ring 305 is large, even if there is a backlash between the pinion 303 and the gear portion 305i, the gear meshing sound, the reverse sound, etc. are reduced.

  Moreover, it has the light-shielding part 305m and plays the role of a sensor by entering and exiting the slit of the photo interrupter 308. Used for initialization of the light quantity control device.

  The diaphragm blade 304 has a shaft 304b1 (to h1) and a shaft 304b2 (to h2). The diaphragm blades 304 are formed by pressing a resin film (PET sheet material or the like). The shafts 304b1 (up to 304h1) and the shafts 304b2 (up to 304h2) are integrated by bonding, welding, outsert molding, or the like, formed by resin molding. Or what was formed with the metal pin may be integrated by adhesion, welding, caulking, or the like.

  The cover member 306 has a cam groove (or long groove) 306b (to h) that engages with the shaft 304b2 (to 304h2) of the diaphragm blade 304. The cover member 306 has a light passage opening 306a. The cover member 306 is connected to the base member 302 mainly by hook shape or screw tightening (not shown). The drive ring 305 and the diaphragm blade 304 are driven in the space formed by the base member 302 and the cover member 306.

  Here, the movement of the aperture blade 304 of the third embodiment will be described. The shaft 304b1 of the diaphragm blade 304 is engaged with the hole 305b of the drive ring 305. When the pinion 303 rotates, a force is applied to the driven portion 305i of the drive ring 305, and the drive ring 305 rotates. When the drive ring 305 rotates, the aperture blade 304 rotates together with the drive ring 305 because the hole 305b of the drive ring 305 and the shaft 304b1 of the aperture blade 304 are engaged. At this time, since the shaft 304b2 of the diaphragm blade 304 is engaged with the cam groove (or long groove) 306b of the cover member, the diaphragm blade 304 rotates while being guided by the cam groove (or long groove) 306b. By rotating the plurality of aperture blades 304 as described above, the aperture blades 304 can enter and exit the light passage opening 302a of the base member 302, and the aperture shape can be adjusted.

  Further, in the third embodiment, the cam grooves (or long grooves) 306b to 306b of the cover member 306 have different shapes as appropriate. By changing the shape of the cam groove, the speed of entering the light passage opening 302a of each diaphragm blade 304 can be changed.

  FIG. 10 shows the aperture shape seen from the cover member 306 side. In the process of changing to (A) full aperture, (B) intermediate aperture, and (C) small aperture, the shaft 304b2 (up to 304h2) of the aperture blade 304 moves along the cam grooves 306b through 306h of the cover member 306. Although not shown, also in the third embodiment, similarly to the first embodiment, only the lower side of the light passage opening 302a can be temporarily shielded by the diaphragm blades 304 (the same state as in FIG. 2B). .

  FIG. 11 is a view in which the cover member 306 is removed from FIG. The holes 305b to 305h of the drive ring 305 of Embodiment 3 are arranged at different angles with the light passage opening 302a as the center. This is because (C) the minimum diaphragm aperture shape is arranged such that the arc length per aperture blade is the same. Thereby, even at the minimum aperture, the aperture shape becomes a shape close to a regular polygon as many as the number of blades, and natural image quality can be obtained even with respect to blur where the aperture shape appears remarkably.

  The angle between the holes of the drive ring 305 is provided in the power transmission member that engages with the aperture of the aperture blade that moves the blade tip toward the lower side of the optical path of the fixed aperture in the process of changing from the aperture opening to the minimum aperture. If the angle between the holes is smaller than the angle between the holes provided in the power transmission member with which the aperture blade blade moves so that the blade tip moves toward the upper side of the optical path of the fixed aperture, the minimum Since the aperture shape at the time of aperture is close to a regular polygon as many as the number of blades, it is advantageous for blurring where the aperture shape appears remarkably.

  In the blade driving device of the third embodiment, as in the first embodiment, the center of the aperture opening gradually moves away from the center of the fixed aperture 302a in the process of changing from open to minimum aperture. That is, even if the blade driving device of the third embodiment is used, harmful light can be shielded to the minimum necessary as described with reference to FIGS. 3, 4, and 5, and ghosting can be prevented. It is.

  In the present embodiment, the shafts 305b to 305h of the drive ring 305 are arranged at different angles around the light passage opening 302a in consideration of the diaphragm shape at the time of the minimum diaphragm, but the same with respect to the light passage opening 302a. Even when arranged at an angle, the center of the aperture opening gradually moves away from the center of the fixed aperture 302a in the process of changing from the full aperture to the minimum aperture, which is effective for ghost prevention.

<Embodiment 4>
In FIG. 12, the disassembled perspective view of the aperture_diaphragm | restriction apparatus as a blade drive device which is an example of the blade drive device which is Embodiment 4 of this invention is shown. FIGS. 13 and 14 show the process of changing from full aperture to minimum aperture in the order of (A) → (B) → (C).
In Embodiment 4, the aperture blade hole and the drive ring shaft in Embodiment 2 are engaged, and the portion of the aperture blade cam groove (or long groove) and the base member shaft engaged is the aperture blade. And the shaft of the base member are engaged, and the cam groove (or long groove) of the blade and the shaft of the drive ring are engaged.

  In FIG. 12, the base member 402 has a light passage opening 402a formed at the center. The base member 402 has shafts 402b to 402h that engage with holes 404b1 to 404h1 of the diaphragm blade 404, which will be described later. The base member 402 is formed by resin molding or the like. A drive unit 401 is attached to the base member 402. The driving unit 401 uses, for example, a stepping motor, a galvano motor, or the like. A pinion 403 is attached to the rotation shaft 401 a of the drive unit 401.

  The drive ring 405 has a through hole that constitutes at least a part of the light passage path, and is formed from an annular sheet-like member (endless ring-like member) that surrounds a path (light passage path) through which light passes, It rotates around the light passage path. The driving ring 405 engages with a diaphragm blade described later. That is, the drive ring 405 is configured so that the diaphragm blade 404 enters and exits the light passage path in conjunction with the rotation of the drive ring 405, and therefore a member (power transmission member) for driving the diaphragm blade 404 ) The drive ring 405 includes shafts 405b to 405h and driven parts 405i that engage with the light passage openings 405a and cam grooves (or long grooves) 404b2 to 404h2 of the diaphragm blade 404.

  The drive ring 405 is created by resin molding or the like. For example, it may be created by pressing a resin film (PET sheet material or the like). When press working can be performed, the shape accuracy can be formed with higher accuracy than the shape accuracy of resin molding, so that the drawing accuracy can be high.

  As the thickness of the resin film, a material having a thickness of 0.03 mm to 0.30 mm can be used. By reducing the thickness as much as possible, the inertia during rotation can be reduced, and the diaphragm device can be operated at high speed. The drive ring 405 is supported by the base member 402 and the cover member 406 so as to be optimally movable in both the thrust direction and the radial direction, so that the deformation of the drive ring 405 is minimized even if the thickness is reduced.

  When the drive ring 405 is made of a resin film, the shafts 405b to 405h are integrated by bonding, welding, outsert molding, or the like, made by resin molding. Or what was formed with the metal pin may be integrated by adhesion, welding, caulking, or the like.

  The drive ring 405 may be made of a material that is surface-treated on one side or both sides. Examples of the surface treatment include sliding coating, antistatic treatment, and antireflection treatment. By sliding coating, friction with the base member 402, which is a part that slides with the drive ring, diaphragm blades 404, and a cover member 406, which will be described later, can be reduced, and power-saving operation is possible. In addition, by performing antireflection treatment, it is possible to suppress the reflection of light entering the light amount adjusting device and prevent the occurrence of ghost, flare, etc. when the light amount adjusting device is incorporated in the lens barrel. it can.

  Further, the drive ring 405 has a gear portion which is a driven portion 405i. The driven portion 405 i meshes with the pinion 403. The rotational force generated in the drive unit 401 is transmitted from the pinion 403 to the driven unit 405i, and the drive ring 405 rotates. In the meshing of the gear portion 405i of the drive ring 405 and the gear of the pinion 403, the gear portion 405i is thin and the meshing area of the gear is small, so that the meshing sound between the gears is small. Further, since the mass difference between the pinion 403 and the drive ring 405 is large, even if there is a backlash between the pinion 403 and the gear portion 405i, the gear meshing sound, the reverse sound, etc. are reduced.

  Further, the light shielding portion 405m functions as a sensor by entering and exiting the slit of the photo interrupter 408. Used for initialization of the light quantity control device.

  In FIG. 12, the aperture blade 404 has a hole 404b1 (to 404h1) and a cam groove (or long groove) 404b2 (to 404h2). The diaphragm blade 404 is created by pressing a resin film (PET sheet material or the like).

  The cover member 406 has a light passage opening 406a. The cover member 406 is connected to the base member 402 mainly by hook shape or screw fastening (not shown). The drive ring 405 and the diaphragm blade 404 are driven in the space formed by the base member 402 and the cover member 406.

  Here, the movement of the diaphragm blade 404 according to the fourth embodiment will be described. The hole 404b1 of the diaphragm blade 404 engages with the shaft 402b of the base member. The cam groove (or long groove) 404 b 2 of the diaphragm blade 404 engages with the shaft 405 b of the drive ring 405. When the pinion 403 rotates, a force is applied to the driven portion 405i of the drive ring 405, and the drive ring 405 rotates. When the drive ring 405 rotates, the shaft 405b of the drive ring 405 and the cam groove (or long groove) 404b2 of the diaphragm blade 404 engage with each other, so that the diaphragm blade 404 rotates while being guided by the cam groove (or long groove) 404b2. . At this time, the hole 404b1 of the diaphragm blade 404 is engaged with the shaft 402b of the base member. By rotating the plurality of aperture blades 404 as described above, the aperture blades 404 can enter and exit the light passage opening 402a of the base member 402, and the aperture shape can be adjusted.

Furthermore, in the fourth embodiment, the cam grooves (or long grooves) 404b2 to 404h2 of the aperture blade 404 are formed in different shapes as appropriate. By changing the shape of the cam groove, the speed at which each diaphragm blade 404 enters the light passage opening 402a can be changed.

  FIG. 13 shows the aperture shape viewed from the cover member 406 side. In the process of changing to (A) full aperture, (B) intermediate aperture, and (C) minimum aperture, the aperture blade 404 moves the cam groove 404b2 (~ h2) along the shaft 405b (~ h) of the drive ring 405. . Although not shown, also in the fourth embodiment, similarly to the first embodiment, only the lower side of the light passage opening 402a can be temporarily shielded by the diaphragm blades 404 (the same state as in FIG. 2B). .

  FIG. 14 is a view in which the cover member 406 is removed from FIG. The axes 405b to 405h of the drive ring 405 of the fourth embodiment are arranged at different angles with the light passage opening 402a as the center. This is because (C) the small diaphragm aperture shapes are arranged so that the arc length per aperture blade is the same. As a result, even when the aperture is small, the aperture shape is close to a regular polygon as many as the number of blades, and a natural image quality can be obtained even with respect to blur where the aperture shape appears remarkably.

  The angle between the shafts of the drive ring gives a driving force to the diaphragm blades, where the blade tip engages with the aperture of the diaphragm blades moving toward the lower side of the optical path of the fixed aperture in the process of changing from the full aperture to the minimum diaphragm. The angle between the shafts installed on the power transmission member is set on the power transmission member that gives a driving force to the diaphragm blades, where the blade tip engages with the hole of the diaphragm blades that move toward the upper optical path of the fixed opening. If it is arranged so that the angle is smaller than the angle between the axes, the aperture shape at the time of the minimum aperture is close to the regular polygon for the number of blades, which is also advantageous for blurring where the aperture shape appears remarkably Become.

14A to 14C, the diaphragm blades 404 engaged with the shafts 402b to 402h each have a different rotation angle in a predetermined amount of rotation of the drive ring 405. The cam grooves 404b2 to 404h2 are formed as described above, and the contact positions at which the shafts 405b to 405h actually contact the cam grooves 404b2 to 404h2 are in contact with the center of the fixed opening 402a at different angles. It has become.

  In the blade driving device of the fourth embodiment, as in the first embodiment, the center of the aperture opening gradually moves away from the center of the fixed aperture 402a in the process of changing from open to small aperture. That is, even if the blade driving device of the fourth embodiment is used, harmful light can be shielded to the minimum necessary and the occurrence of ghost can be prevented as described in FIGS. It is.

  In this embodiment, the shafts 405b to 405h of the drive ring 405 are arranged at different angles around the light passage opening 402a in consideration of the shape of the diaphragm at the time of a small stop, but the same with the light passage opening 402a as the center. Even when arranged at an angle, the center of the aperture opening gradually moves away from the center of the fixed aperture 402a in the process of changing from open to small aperture, which is effective for ghost prevention.

<Embodiment 5>
FIG. 15 shows a schematic configuration of a video camera (imaging device) as an optical apparatus equipped with the diaphragm device described in the first to fourth embodiments.
In the lens barrel portion 21 of the video camera, a photographic optical system including the variable magnification lens 32, the diaphragm device 20 of Examples 1 and 2 and the focus lens 29 is accommodated.

  The imaging element 25 is configured by a photoelectric conversion element such as a CCD sensor or a CMOS sensor, and photoelectrically converts a subject image formed by the photographing optical system and outputs an electrical signal. The brightness of the subject image formed on the image sensor 25 (that is, the amount of light reaching the image sensor 25) is appropriately set by changing the aperture of the aperture device 20 or moving the ND filter back and forth. Can do.

  The electrical signal output from the image sensor 25 is subjected to various image processing by the image processing circuit 26. Thereby, a video signal (video output) is generated.

  The controller 22 controls the zoom motor 31 in response to a zoom switch (not shown) being operated by the user, and moves the zoom lens 32 to perform zooming. The controller 22 detects the contrast of the video signal, controls the focus motor 28 according to the contrast, and moves the focus lens 29 to perform autofocus.

  Further, the controller 22 controls the diaphragm driving unit 1 (and the ND driving unit) of the diaphragm device 20 based on the luminance information in the video signal, and adjusts the light amount. Thereby, blur and ghost at the time of shooting can be made into a natural shape, and high-quality video can be recorded. In addition, since the aperture device 20 incorporated in the lens barrel portion is small, the lens barrel portion and the entire video camera can be miniaturized.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

101 Diaphragm drive unit 102 Base member (base plate)
103 Driving lever 104 Diaphragm blade 105 Diaphragm blade 106 Cover 107 Image sensor 202 Base member 204 Diaphragm blade 205 Drive ring 205b-h Axis (engaging portion)

Claims (8)

An opening forming member that forms a fixed opening through which light passes;
A plurality of aperture blades that move forward and backward with respect to the fixed aperture to form an aperture aperture;
A power transmission member that transmits a driving force to the plurality of diaphragm blades by a rotation operation;
A plurality of engaging portions disposed on the power transmission member and engaged with engaged portions of the plurality of diaphragm blades;
The plurality of engaging portions are arranged based on respective positions in the fixed opening of the diaphragm blades that form the diaphragm opening formed so that the center of the opening is different from the fixed opening. A blade drive device. The power transmission member is provided in an annular shape so as to surround the fixed opening,
The engaging portion is arranged on the same circumference of the power transmission member on the direction side where the center of the aperture opening is located with respect to the center of the fixed opening. The blade driving device according to claim 1, wherein the blade driving device is disposed more densely than the engaging portion on the opposite side across the gap. In the process of changing from full aperture to minimum,
3. The blade driving device according to claim 1, wherein the diaphragm blade entering the fixed opening temporarily enters only the lower side of the optical path of the fixed opening. 4. A restricting portion that is provided on the opening forming member and restricts the rotational movement of the diaphragm blade by engaging with the diaphragm blade;
The said restriction | limiting part is provided so that a predetermined angle may be made with respect to the center of the said fixed opening between the said engaging parts engaged with the said same aperture blade. The blade drive device according to any one of claims. The diaphragm blades rotate by the power transmission member,
Among the diaphragm blades, the diaphragm blade that engages with the engaging portion on the opposite side with the rotation angle of the diaphragm blade engaging with the densely arranged engaging portion sandwiching the center of the fixed opening. The blade driving device according to claim 2, wherein the blade driving device is larger than the rotation angle. An opening forming member that forms a fixed opening through which light passes;
A plurality of aperture blades that move forward and backward with respect to the fixed aperture to form an aperture aperture;
A power transmission member that transmits a driving force to the plurality of diaphragm blades by a rotation operation;
A plurality of engaging portions disposed on the power transmission member and engaged with engaged portions of the plurality of diaphragm blades;
The plurality of engaging portions are arranged to be offset with respect to the rotation center of the power transmission member, so that the center of the aperture opening is formed at a position different from the center of the fixed opening. apparatus. An opening forming member that forms a fixed opening through which light passes;
A plurality of aperture blades that move forward and backward with respect to the fixed aperture to form an aperture aperture;
A power transmission member that transmits a driving force to the plurality of diaphragm blades by a rotation operation;
A plurality of engaging portions disposed on the power transmission member and engaged with engaged portions of the plurality of diaphragm blades;
A regulating portion provided on the opening forming member and regulating the rotational movement of the diaphragm blade by engaging with the diaphragm blade;
The blade drive, wherein each diaphragm blade is engaged so that the engagement position with the engaging portion or the restricting portion is at an angle different from that of the other diaphragm blades with respect to the center of the fixed opening. apparatus.   An optical apparatus comprising the blade driving device according to claim 1.

Images