JP4684410B2 - Light amount adjusting device, photographing lens barrel and imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel used in an optical apparatus such as a video camera.
[0002]
[Prior art]
As a zoom lens for a video camera, for example, there is a zoom lens composed of four lens groups of a fixed convex, a movable concave, a fixed convex, and a movable convex in order from the subject side.
[0003]
9A and 9B show a lens barrel structure of a general zoom lens having a four-group lens configuration. In addition, (B) has shown the AA sectional view in (A).
[0004]
The four lens groups 201a to 201d constituting the zoom lens include a fixed front lens 201a, a variator lens group 201b that performs a zooming operation by moving along the optical axis, a fixed afocal lens 201c, And a focusing lens group 201d that moves along the optical axis to maintain and focus on the focal plane during zooming.
[0005]
Guide bars 203, 204a, and 204b are arranged in parallel with the optical axis 205, and guide and prevent rotation of the moving lens group. The DC motor 206 serves as a drive source for moving the variator lens group 201b.
[0006]
The front lens 201 a is held by the front lens barrel 202, and the variator lens group 201 b is held by the V moving ring 211. The afocal lens 201c is held by the intermediate frame 215, and the focusing lens group 201d is held by the RR moving ring 214. Further, the diaphragm unit 218 is held in the intermediate frame 215.
[0007]
The front lens barrel 202 is positioned and fixed to the rear lens barrel 216. The guide bar 203 is positioned and supported by both the lens barrels 202 and 216, and the guide screw shaft 208 is rotatably supported. The guide screw shaft 208 is driven to rotate by transmitting the rotation of the output shaft 206 a of the DC motor 206 through the gear train 207.
[0008]
The V moving ring 211 that holds the variator lens group 201b has a pressing spring 209 and a ball 210 that engages with a screw groove 208a formed in the guide screw shaft 208 by the force of the pressing spring 209, and is a DC motor. When the guide screw shaft 208 is rotationally driven by 206, the guide screw shaft 208 moves forward and backward in the optical axis direction while being guided and restricted by the guide bar 203.
[0009]
Guide bars 204 a and 204 b are fitted and supported on the rear barrel 216 and the intermediate frame 215 positioned on the rear barrel 216. The RR movable ring 214 can advance and retreat in the optical axis direction while being guided and restricted by the guide bars 204a and 204b.
[0010]
The RR moving ring 214 that holds the focusing lens group 201d is formed with a sleeve portion that is slidably fitted to the guide bars 204a and 204b, and the rack 213 is integrated with the RR moving ring 214 in the optical axis direction. It is assembled to become.
[0011]
The stepping motor 212 rotationally drives a lead screw 212a formed integrally with its output shaft. A rack 213 assembled to the RR moving ring 214 is engaged with the lead screw 212a. When the lead screw 212a rotates, the RR moving ring 214 moves in the optical axis direction while being guided by the guide bars 204a and 204b. To do.
[0012]
Note that a stepping motor may be used as a driving source for the variator lens group, similarly to the driving source for the focusing lens group.
[0013]
The front lens barrel 202, the intermediate frame 215, and the rear lens barrel 216 form a lens barrel main body that accommodates a lens or the like in a substantially sealed manner.
[0014]
Further, when moving the lens group holding frame using such a stepping motor, after detecting that the holding frame is positioned at one reference position in the optical axis direction using a photo interrupter or the like, the stepping motor The absolute position of the holding frame is detected by continuously counting the number of applied driving pulses.
[0015]
Next, the configuration of the aperture unit 218 will be described with reference to FIG. The aperture unit 218 is a type of aperture unit in which two aperture blades 23a and 23b are moved substantially in parallel to each other in opposite directions by a single rotary electromagnetic actuator (motor) 23c via a seesaw type drive lever 23d. .
[0016]
23e is the base plate of the diaphragm unit so is there. The diaphragm blade 23a is substantially J-shaped when viewed from the optical axis direction, and a large semicircular opening forming notch 23a1 is formed at the upper edge of the lower curved portion thereof. Further, the lower end portion 23a2 of the opening forming notch 23a1 is formed in an inverted triangular shape.
[0017]
Guide slits 23a3 and 23a4 that are vertically spaced apart from each other and extend in the vertical direction are formed at positions near the left edge of the diaphragm blade 23a, and guide slits 23a5 that extend in the vertical direction are formed at positions near the right edge, respectively. Has been.
[0018]
In addition, a long connecting hole 23a6 extending in the left-right direction is formed above the upper left guide slit 24a3 of the diaphragm blade 23a.
[0019]
The left guide slits 23a3 and 23a4 are engaged with support pins 23e1 and 23e2 formed on the ground plate 23e, respectively, and the right guide slit 23a5 is engaged with a support pin 23e3 also formed on the ground plate 23e. is doing. Thereby, the aperture blade 23a is supported by the main plate 23e so as to be movable only in the vertical direction.
[0020]
The diaphragm blade 23b is substantially h-shaped when viewed from the optical axis direction, and a large semicircular opening forming notch 23b1 is formed at the lower edge of the lower curved portion. The upper end portion 23b2 of the opening forming notch 23b1 is formed in a triangular shape.
[0021]
Guide slits 23b3 and 23b4 that are vertically spaced apart from each other and extend in the vertical direction are formed at positions near the right edge of the diaphragm blade 23b, and guide slits 23b5 that extend in the vertical direction are formed at positions near the left edge, respectively. Has been.
[0022]
Further, a long connecting hole 23b6 extending in the left-right direction is formed above the guide slit 23b3 on the upper right side of the diaphragm blade 23b.
[0023]
Support pins 23e4 and 23e3 formed on the base plate 23e are engaged with the right guide slits 23b3 and 23b4, respectively, and a support pin 23e2 is engaged with the left guide slit 23b5. Thereby, the aperture blade 23b is supported by the main plate 23e so as to be movable only in the vertical direction.
[0024]
23d is a motor In Therefore, the seesaw type lever is driven to swing around the center in the longitudinal direction. Then, pins provided at both ends of the seesaw type lever 23d are engaged with the long connecting holes 23a6 and 23b6 of the diaphragm blades 23a and 23b, respectively. Therefore, when the motor rotates and the drive lever 23d swings, the diaphragm blades 23a and 23b are driven in opposite directions to each other, and the respective opening forming notches 23a1 and 23b1. Formed by The aperture area of the aperture opening changes.
[0025]
Further, in a diaphragm unit of the type as shown in FIG. 10, as shown in FIG. 11, ND filters 27a to 27d are arranged at positions aligned with the diaphragm blades 23a and 23b so as to be able to advance and retreat with respect to the diaphragm opening. (Japanese Unexamined Patent Publication No. 2000-106649 etc.).
[0026]
The ND filters 27a to 27d are held by the filter holding member 26 so as to cover the opening 26d of the filter holding member 26 formed in a substantially U shape when viewed from the optical axis direction. The left and right widths of the opening 26d are notches for forming the openings of the diaphragm blades 23a and 23b. 23 a1, 23 The left and right widths of b1 are substantially the same or slightly larger.
[0027]
Guide slits 26 extending in the vertical direction are located near the left and right edges of the filter holding member 26. a Further, a connecting long hole 26c extending in the left-right direction is formed below the left guide slit 26a. And the guide slit 26 a Although not shown in this figure, the support pins 23e1, 23e2, 23e3, and 23e4 of the main plate 23e shown in FIG. Thereby, the filter holding member 26 is supported so as to be movable only in the vertical direction.
[0028]
The ND filters 27a to 27d have different transmittances. The ND filter 27a located on the uppermost side has the highest transmittance (that is, the density is low), and the ND filter located on the lower side has a lower transmittance. ( Concentration It is dark).
[0029]
Reference numeral 24 denotes a diaphragm actuator (motor), and an arm 25 is attached to the output shaft thereof. A driving pin 25 a is provided at the tip of the arm 25, and the driving pin 25 a is engaged with a connecting long hole 26 c of the filter holding member 26.
[0030]
For this reason, when the diaphragm actuator 24 is actuated to swing the arm 25, the filter holding member 26 moves in the vertical direction, and the ND filters 27a to 27d move forward and backward with respect to the position overlapping the diaphragm opening.
[0031]
Although not shown, the ND filter (filter holding member) 26 On the side opposite to the base plate 23e, a pressing plate for pressing the ND filter toward the base plate side is provided.
[0032]
For example, if the aperture diameter is too small for a bright subject, image quality deterioration due to so-called small aperture diffraction and dust reflection due to an increase in the depth of focus become problems. In particular, when the image sensor becomes smaller and the pixel pitch becomes finer, the influence of diffraction increases.
[0033]
For this reason, it is possible to prevent diffraction and the like by using a diaphragm unit that combines the diaphragm blades and two or more types of ND filters as described above and overlapping the ND filters 27a to 27d on the diaphragm aperture (small diaphragm). It becomes.
[0034]
[Problems to be solved by the invention]
However, as described above, in the type of diaphragm unit in which the two diaphragm blades are moved substantially in parallel to each other via the seesaw type drive lever, the opening shape is irregular (for example, a slit shape) when the diaphragm is extremely small. ), And there is concern about the effect of diffraction.
[0035]
In addition, the irregular shape of the aperture also causes a problem that the amount of light on the periphery of the screen becomes non-uniform.
[0036]
Further, in a diaphragm unit that drives the ND filter separately from the diaphragm blades, if the diaphragm blades and the ND filter are arranged too close to each other, the diaphragm blades may be caught by the ND filter. For this reason, as proposed in Japanese Patent Laid-Open Nos. 2000-250091 and 2000-122109, it is necessary to provide a partition plate for partitioning the working space between the diaphragm blades and the ND filter.
[0037]
In this case, the thickness in the optical axis direction of the aperture unit excluding the actuator is the thickness of the base plate, the operating space of the aperture blade, the thickness of the partition plate, the operating space of the ND filter, and the thickness of the holding plate. There is also a problem that it becomes the sum of and becomes quite thick.
[0038]
Further, in the diaphragm unit that drives the ND filter separately from the diaphragm blades, if the ND filter is driven in the vertical direction within a plane substantially orthogonal to the optical axis direction, there is a problem that the entire diaphragm unit is enlarged in the vertical direction.
[0039]
[Means for Solving the Problems]
In order to solve the above problem, in the first invention of the present application, A plurality of light shielding blades that form a light passage opening by an outer edge having a curvature, and change an opening area of the light passage opening by rotation, a first actuator for driving the plurality of light shielding blades, and the light passage A light amount adjusting device having an ND filter that advances and retreats with respect to a position overlapping the mouth in the optical axis direction, and a second actuator for driving the ND filter forward and backward, and an output shaft of the first actuator includes A first arm extending in the optical axis direction is attached, and the first arm is driven to swing in the plane orthogonal to the optical axis by the first actuator and connected to the plurality of light shielding blades. A second arm extending in the optical axis direction is attached to the output shaft of the second actuator, and the second arm is connected to the second actuator. The plurality of light shielding blades and the ND are driven between the plurality of light shielding blades and the ND filter in the optical axis direction. A support plate that supports the filter is disposed, and in the optical axis direction, the first actuator is disposed on the opposite side of the light shielding blade with the support plate interposed therebetween, and the second actuator is disposed with the support plate interposed therebetween. In the optical axis direction, the first arm and the second arm are arranged so as to overlap with each other. .
[0040]
As a result, the shading blade Rotate In addition to having a blade mechanism in which the light passage opening is not easily deformed even in a small aperture state of the type, the support plate itself such as the base plate can prevent interference between the light shielding blade and the ND filter, and can ensure smooth operation of the light shielding blade and the ND filter. In addition, by arranging the first and second actuators on opposite sides of the support plate, the dimensions in the direction perpendicular to the optical axis are compared with the case where the first and second actuators are arranged on both sides in the direction perpendicular to the optical axis. Can be realized.
[0041]
In the second invention of the present application, A plurality of light shielding blades that form a light passage opening by an outer edge having a curvature, and a blade driving mechanism that rotates the plurality of light shielding blades by a drive ring that rotates around the optical axis to change the opening area of the light passage opening. A first actuator for rotationally driving the drive ring, an ND filter that moves forward and backward with respect to a position overlapping the light passage port in the optical axis direction, and a second actuator for driving the ND filter forward and backward, The first arm extending in the optical axis direction is attached to the output shaft of the first actuator, and the first arm is moved by the first actuator. The second actuator is driven to swing in a plane orthogonal to the optical axis and connected to the drive ring, and the second actuator extends in the optical axis direction to the output shaft of the second actuator. An arm is attached, and the second arm is driven to swing in the plane orthogonal to the optical axis by the second actuator, and is connected to the ND filter. In the optical axis direction, the blade drive A support plate that supports the blade driving mechanism and the ND filter is disposed between the mechanism and the ND filter, and in the optical axis direction, the first actuator is sandwiched between the support plate and the blade driving mechanism. Arranged on the opposite side, the second actuator is arranged on the opposite side of the ND filter across the support plate, and the first arm and the second arm overlap in the optical axis direction. Characterized by being placed in position .
[0042]
As a result, the plurality of light shielding blades are rotated by the rotation of the drive ring. Rotation In addition to having a blade drive mechanism that makes it difficult for the light passage aperture to be deformed even in a small aperture state, the support plate such as the base plate itself prevents interference between the light shielding blade and the ND filter and ensures smooth operation of the light shielding blade and the ND filter. In addition, by disposing the drive ring within the thickness in the optical axis direction of the support plate, the ND filter driven separately from the light shielding blade is provided, but the thickness in the optical axis direction is thin, and further, the first and second actuators are provided. By arranging the support plates on opposite sides of each other, a light amount adjusting device having a smaller dimension in the direction perpendicular to the optical axis than in the case where the first and second actuators are arranged on both sides in the direction perpendicular to the optical axis is realized. Is possible.
[0043]
In the first and second aspects of the invention, the first actuator is disposed on the side opposite to the light shielding blade or the blade driving mechanism (that is, the ND filter side) with the support plate interposed therebetween, so that in the optical axis direction, Since the diaphragm drive lever and the support plate are disposed between the first actuator and the diaphragm blade, conventionally, the diaphragm blade, the diaphragm drive lever, and the first actuator are arranged only on one side in the optical axis direction with respect to the support plate. Has contributed to space saving in the optical axis direction.
[0044]
Further, by disposing the second actuator on the opposite side of the ND filter (that is, on the light shielding blade or blade driving mechanism side) with the support plate in between, the second actuator and the ND filter are arranged in the optical axis direction. Since the ND drive lever and the support plate are disposed between them, conventionally, an ND filter is provided only on one side in the optical axis direction with respect to the support plate. ND In contrast to the layout of the drive lever and the second actuator, this contributes to space saving in the optical axis direction.
[0045]
Further, by using a ND filter having a plurality of transmission regions each having a different density, and arranging a transmission region having a lighter concentration toward the front end side in the direction of entry to the position overlapping the light passage opening in the ND filter, Threaded part in mouth (Part not covered with ND filter) It is possible to prevent the influence of diffraction due to the large difference in transmittance between the portion where the ND filter and the ND filter overlap.
[0046]
Further, in the photographing lens barrel that includes the light amount adjusting device described above and forms an image on the rectangular image pickup device through the light amount adjusting device, by tilting the forward / backward driving direction of the ND filter with respect to the side of the image pickup device, It is possible to reduce the dimension in the direction in which the side of the ND filter driving range extends.
[0047]
In addition, when the arm member is driven to swing by the second actuator and the ND filter is moved forward and backward by this arm member, the swing range of the arm member is set in the direction in which the above-mentioned side of the image sensor in the second actuator is extended. By making it fit on the optical axis side with respect to the end portion, it is possible to further reduce the dimension of the entire apparatus in the direction in which the side extends.
[0048]
By using such a photographic lens barrel, it is possible to reduce the size of the imaging apparatus.
[0049]
Even when the forward / backward drive direction of the ND filter is slanted as described above, the front end edge of the ND filter and the density boundary line in the ND filter are substantially parallel to the upper side of the image sensor, so that the ND filter can be moved forward / backward. It is possible to prevent a sense of incongruity from occurring in the brightness change in the imaging screen.
[0050]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show the configuration of a photographic lens barrel including a light amount adjustment unit (light amount adjustment device) according to an embodiment of the present invention.
[0051]
In these figures, L1 is a fixed first group lens, L2 is a second group lens that performs a zooming operation by moving in the direction of the optical axis, and L3 is moved in a plane perpendicular to the optical axis in accordance with camera shake or the like. Thus, a third lens unit L4 that performs an image blur correction operation, and a fourth lens unit L4 that performs a focusing operation by moving in the optical axis direction.
[0052]
In the lens barrel of the present embodiment, the first group lens L1 has a convex power, the second group lens L2 has a concave power, the third group lens L3 has a convex power, and the fourth group lens L4 has a convex power. The optical system constitutes a four-group variable magnification optical system having convex and concave portions in order from the subject side.
[0053]
Reference numeral 1 denotes a front lens barrel unit that holds the first lens group L1, and reference numeral 2 denotes a variable magnification moving frame that holds the second lens group L2. Reference numeral 3 denotes a shift unit that holds the third group lens L3 movably in a plane perpendicular to the optical axis, and 4 denotes a focusing movement frame that holds the fourth group lens L4.
[0054]
Reference numeral 5 denotes a rear lens barrel that fixes and holds an image pickup device such as a CCD, and the two guide bars 6 and 7 are positioned and fixed by the front lens barrel unit 1 and the rear lens barrel 5. A guide bar 8 is positioned and fixed between the shift unit 3 and the rear barrel 5.
[0055]
The variable magnification moving frame 2 is supported by the guide bars 6 and 7 so as to be movable in the optical axis direction, and the focusing moving frame 4 is supported by the guide bars 6 and 8 so as to be movable in the optical axis direction. The variable magnification moving frame 2 and the focusing moving frame 4 are each fitted to one guide bar by a sleeve portion having a predetermined length in the optical axis direction, thereby preventing the optical axis direction from falling down. Then, by engaging the other guide bar with the U groove, rotation around the one guide bar is prevented.
[0056]
The shift unit 3 is positioned by the front lens barrel unit 1 and is held between the rear lens barrel 5 and the front lens barrel unit 1.
[0057]
Reference numeral 9 denotes a light amount adjustment unit that changes the amount of light incident on the optical system from the first lens unit L1.
[0058]
The light quantity adjusting unit 9 has a so-called iris diaphragm that changes the aperture diameter by opening and closing the six diaphragm blades. Further, the light quantity adjusting unit 9 is configured so that the three-density ND filter can be advanced and retracted to a position where it overlaps the aperture of the aperture by driving separately from the aperture blade.
[0059]
The light quantity adjustment unit 9 is fastened and fixed to the shift unit 3 from the front by three screws. The detailed configuration of the light quantity adjustment unit 9 will be described later.
[0060]
The rear lens barrel 5 is positioned on the front lens barrel unit 1 and, at the same time, is clamped and fixed from behind by three screws with the shift unit 3 interposed therebetween as described above.
[0061]
Reference numeral 10 denotes a lead screw for moving the in-focus moving frame 4 in the optical axis direction, and a rotor magnet 10a having a bearing shape at the front and rear thereof and magnetized in multiple poles at the rear is fixed.
[0062]
Reference numeral 11 denotes a stepping motor stator unit for rotating the rotor magnet 10a, and the lead screw 10 is rotatably supported by bearings provided in the shift unit 3 and the stepping motor stator unit 11.
[0063]
The lead screw 10 is engaged with a rack 4a attached to the focusing movement frame 4. The rotation of the lead screw 10 drives the focusing movement frame 4 together with the rack 4a in the optical axis direction.
[0064]
Note that the torsion coil spring 4b disposed between the focusing moving frame 4 and the rack 4a causes the focusing moving frame 4 to move in the guide bar radial direction with respect to the guide bars 6 and 8, and the rack 4a to the focusing moving frame 4. On the other hand, the rack 4a is biased toward each other in the direction of the optical axis and in the meshing direction with the lead screw 10, thereby eliminating backlash at each part.
[0065]
Reference numeral 12 denotes a lead screw for moving the second group lens L2 in the optical axis direction, and a rotor magnet 12a having a bearing shape at the front and rear thereof and magnetized in multiple poles at the rear is fixed.
[0066]
Reference numeral 13 denotes a stepping motor stator unit for rotating the rotor magnet 12a. The lead screw 12 is rotatably supported by bearings provided in the shift unit 3 and the stepping motor stator unit 13.
[0067]
The lead screw 12 meshes with a rack 2a attached to the variable magnification moving frame 2. The rotation of the lead screw 12 drives the variable magnification moving frame 2 together with the rack 2a in the optical axis direction.
[0068]
Note that the torsion coil spring 2b disposed between the variable magnification moving frame 2 and the rack 2a causes the variable magnification moving frame 2 to move in the guide bar radial direction with respect to the guide bars 6 and 7, and the rack 2a to the variable magnification moving frame 2. On the other hand, the rack 2a is biased toward each other in the direction of the optical axis and in the meshing direction with the lead screw 12, thereby eliminating backlash at each part.
[0069]
Each of the stepping motor stator units 11 and 13 is fixed to the rear barrel 5 with two screws.
[0070]
Reference numeral 14 denotes a focus reset switch composed of a photo interrupter, which detects the switching between light shielding and light transmission due to the movement of the light shielding portion 4c formed in the focusing movement frame 4 in the optical axis direction and outputs an electrical signal. A control circuit to be described later determines whether or not the fourth group lens L4 is located at the reference position based on the electrical signal from the focus reset switch 14. The focus reset switch 14 is fixed to the rear barrel 5 with a single screw.
[0071]
Reference numeral 15 denotes a zoom reset switch composed of a photo interrupter, which detects the switching between light shielding and light transmission due to movement of the light shielding portion 2c formed in the variable magnification moving frame 2 in the optical axis direction and outputs an electrical signal. A control circuit, which will be described later, determines whether or not the second group lens L2 is located at the reference position based on the electrical signal from the zoom reset switch 15. The zoom reset switch 15 is fixed to the front lens barrel unit 1 with a single screw.
[0072]
Next, the configuration of the shift unit 3 will be described. The third lens unit L3 can perform a vertical shift for correcting image blur in the PITCH direction (camera vertical direction) and a horizontal shift for correcting image blur in the YAW direction (camera horizontal direction). It is. Each of the vertical direction and the horizontal direction has a dedicated drive system and a shift position sensor, and is driven and controlled independently of each other.
[0073]
Since the vertical and horizontal drive systems and shift position sensors are basically the same in configuration with only a 90 ° phase shift around the optical axis, only the vertical drive system and shift position are shown here. 2 will be described.
[0074]
In FIG. 2, reference numeral 3 b denotes a shift base that is integrated with the lens barrel and serves as the base of the shift unit 3. Reference numeral 3a denotes a shift barrel that holds the third lens unit L3 and is movable in the direction perpendicular to the optical axis with respect to the shift base 3b. The shift barrel 3a includes a front end portion of a compression coil spring 3d. (End of object side) Is fitted and the rear end of the compression coil spring 3d Section (end on the image plane side) Is in contact with a rear sensor base 3c described later. Thereby, the shift barrel 3a Is It is always biased toward the shift base 3b side (front side). An electromagnetic coil 3i described later is positioned and fixed to the shift barrel 3a.
[0075]
The compression coil spring 3d is formed of a phosphor bronze wire or the like so as not to be attracted to detection and drive magnets (which will be described later) arranged in the vicinity thereof.
[0076]
A ball 31 is sandwiched between the shift base 3b and the shift barrel 3a by the urging force of the compression coil spring 3d. Although only one ball 31 is shown in the figure, in reality, three balls 31 are arranged at substantially the same circumferential interval in the plane orthogonal to the optical axis.
[0077]
Further, the ball 31 is formed of SUS304 (austenitic stainless steel) or the like so as not to be attracted by a driving magnet, which will be described later, disposed in the vicinity thereof.
[0078]
Shift base with which three balls 31 come into contact 3b Side surface and shift barrel 3a Each of the side surfaces is a surface perpendicular to the optical axis of the optical system, and by making the nominal diameters of the three balls 31 the same, the shift barrel 3a (that is, the third group lens L3). Can be held and shifted while maintaining a right angle to the optical axis.
[0079]
The sensor base 3c is positioned with respect to the lens barrel by two positioning pins, and is coupled to the shift base 3b by three screws.
[0080]
It should be noted that the balls 31 are not easily dropped from the contact surfaces between the three balls 31 and the respective contact surfaces even when the balls 31 are not urged and clamped by the shift base 3b and the shift barrel 3a. A lubricating oil having a certain viscosity is applied. Thereby, even if the inertial force exceeding the urging force of the compression coil spring 3d acts on the shift barrel 3a, the position of the ball 31 can be prevented from easily shifting even when the ball 31 is in a non-nipping state.
[0081]
Next, the drive mechanism of the shift barrel 3a will be described. 3j is a driving magnet magnetized in two radial directions from the optical axis, 3k is a yoke for closing the magnetic flux on the front side of the driving magnet 3j in the optical axis direction, and 3i is a coil fixed to the shift barrel 3a by adhesion Reference numeral 3h denotes a yoke for closing the magnetic flux on the rear side in the optical axis direction of the driving magnet 3j.
[0082]
The yoke 3h forms a space in which the coil 3i moves together with the driving magnet 3j, and is fixed to the shift base 3b by the magnetic force of the magnet. These drive magnet 3j and yokes 3k and 3h constitute a magnetic circuit.
[0083]
When a current is passed through the coil 3i, a Lorentz force is generated by repulsion between the lines of magnetic force in a direction substantially perpendicular to the magnetization boundary of the two-pole magnetization of the driving magnet 3j, thereby moving the shift column 3a. That is, the drive mechanism of the shift barrel 3a constitutes a so-called moving coil drive mechanism.
[0084]
In the shift unit 3, since such a driving mechanism is arranged in the vertical direction and the horizontal direction, the shift barrel 3a is shift-driven in two directions (vertical direction and horizontal direction) substantially orthogonal within the optical axis orthogonal plane. be able to.
[0085]
Since the shift barrel 3a is pressed against the shift base 3b by the compression coil spring 3d via the three balls 31, the frictional force acting as a load when the shift barrel 3a is driven is caused by the rolling friction of the balls 31. It becomes only. Since the frictional force is extremely small, the shift barrel 3a can be driven and controlled minutely.
[0086]
Next, the position detection of the shift barrel 3a will be described. Reference numeral 3f is a detection magnet magnetized in two radial directions with respect to the optical axis, 3g is a yoke for closing the magnetic flux in the optical axis direction front side of the detection magnet 3f, and both are fixed to the shift barrel 3a. ing.
[0087]
Reference numeral 3e denotes a Hall element that converts the magnetic flux density into an electric signal, and is positioned and fixed to the sensor base 3c. These components constitute a shift position sensor.
[0088]
When the shift barrel 3a is driven in the vertical or horizontal direction, the magnetic flux density detected by the Hall element 3e changes, and this magnetic flux density of By detecting changes as electrical signals through appropriate signal processing, shift barrels 3a Can be detected.
[0089]
Next, the detailed configuration and operation of the light quantity adjustment unit 9 described above will be described with reference to FIGS. 3 shows an exploded view of the light quantity adjustment unit 9, and FIG. 4 shows a cross section of the main part of the light quantity adjustment unit 9. FIG. 5 shows the ND filter driving mechanism in the light amount adjusting unit 9 as viewed from the image plane side.
[0090]
Reference numeral 9a denotes a base plate (support plate) that serves as a base for supporting each component in the light amount adjusting unit 9, and is configured to have an upper ring-shaped portion and a lower flange-shaped portion.
[0091]
A hole portion 9e1 is formed in the outer portion of the six diaphragm blades 9e, and support pins 9a1 provided at six positions on the front surface on the outer peripheral side of the ring-shaped portion of the base plate 9a can rotate in the hole portion 9e1. Is fitted.
[0092]
In addition, a ring-shaped recess 9a2 that is lowered rearward from the front surface on the outer peripheral side is formed on the front surface on the inner peripheral side of the ring-shaped portion of the base plate 9a. Here, the drive ring 9d rotates around the optical axis. It is embedded in possible. As a result, as shown in FIG. 4, the drive ring 9d is within the thickness of the ring-shaped portion of the ground plane 9a in the optical axis direction (however, only a drive pin 9d1 described later protrudes forward).
[0093]
In addition, hemispherical projections 9a3 are formed at a plurality of locations in the circumferential direction on the rear end surface corresponding to the bottom surface of the recess 9a2, and the drive ring 9d rotates smoothly in the recess 9a2 by contacting the projection 9a3. be able to.
[0094]
Drive pins 9d1 are provided at six locations in the circumferential direction on the front surface of the drive ring 9d, and these drive pins 9d1 are fitted into elongated holes 9e2 formed inside the hole 9e1 in the aperture blade 9e. Yes. For this reason, when the drive ring 9d is rotated about the optical axis, the six diaphragm blades 9e swing open and close around the support pin 9a1 of the base plate 9, and the diaphragm aperture formed by these six diaphragm blades 9e. As the area changes, the amount of light passing through the aperture opening increases or decreases.
[0095]
The shape of the aperture opening at this time is maintained substantially circular from the open state to the small aperture state, and does not have an irregular shape. For this reason, the amount of peripheral light can be made uniform even in the small aperture state.
[0096]
As shown in FIG. 4, a ring-shaped pressing plate 9i for pressing the six diaphragm blades 9e and the drive ring 9d toward the ground plate is disposed in front of the ring-shaped portion of the ground plate 9a. It is fixed to 9a.
[0097]
Further, an arm portion 9d3 extending radially outward is formed at one circumferential direction of the drive ring 9d, and a long hole portion 9d2 is formed at the tip of the arm portion 9d3. A pin portion of a diaphragm drive arm 9c, which will be described later, is fitted in the long hole portion 9d2.
[0098]
On the other hand, a filter holding plate 9h1 is disposed on the rear surface side of the main plate 9. On the lower front side of the U-shaped portion of the filter holding plate 9h1, One concentration ( Transmittance 32% ) ND filter 9h2 is pasted, and the two-density ND filter is formed by dividing two types of transmittance areas of 32% and 10% from the upper side to the lower side of the rear surface of the U-shaped part. 9h3 is pasted. The lower part of the 10% transmittance region of the ND filter 9h3 overlaps with the ND filter 9h2.
[0099]
This As shown in FIG. Transmittance in order from the upper side (tip side in the direction of entry into the aperture) 32 % Area 9h9, 10% transmittance area 9h8, and 32% transmittance area 9h7. Has multiple concentration regions An ND filter unit 9h is configured.
[0100]
Here, as shown in FIG. 5, the filter holding plate 9 h 1 has a shape inclined obliquely with respect to the short side 18 a (and the vertical axis V intersecting the optical axis) extending in the vertical direction in the image sensor 18.
[0101]
Similarly, long hole portions 9h12 and 9h13 that are inclined with respect to the short side 18a are formed on the side end side of the filter holding plate 9h1. Guide pins 9a4 provided on the rear surface of the base plate 9 are fitted in the long hole portions 9h12 and 9h13, respectively.
[0102]
Further, a long hole portion 9h11 extending in a direction substantially orthogonal to the longitudinal direction of the long hole portions 9h12 and 9h13 is formed at the lower end of the filter holding plate 9h1, and this long hole portion 9h11 has an ND drive described later. The pin portion 9g1 of the arm 9g is fitted.
[0103]
As shown in FIG. 4, a ring-shaped pressing plate 9j for pressing the ND filter unit 9h toward the ground plate is disposed behind the ring-shaped portion of the ground plate 9a, and is fixed to the ground plate 9a. .
[0104]
Further, the rear surface of the flange-shaped portion of the main plate 9a (that is, the diaphragm blade sandwiching the main plate 9a) 9e A diaphragm drive motor (first actuator) 9b made up of a stepping motor is laid out on the opposite side to the front surface of the flange-shaped portion of the ground plane 9a (that is, the ND filter unit 9h across the ground plane 9a). On the opposite side), an ND drive motor (second actuator) 9f composed of a stepping motor is laid out.
[0105]
The base end portion of the aperture drive arm 9c is connected to the output shaft of the aperture drive motor 9b, and the pin portion provided at the distal end of the aperture drive arm 9c is the elongated hole portion of the drive ring 9d as described above. 9d2 is fitted.
[0106]
Therefore, when the aperture drive motor 9b rotates and the aperture drive arm 9c swings, the drive ring 9d rotates around the optical axis, and the 6 aperture blades 9e swing open and close.
[0107]
The output shaft of the ND drive motor 9f is connected to the base end portion of the ND drive arm 9g, and the pin portion 9g1 provided at the tip of the ND drive arm 9g is connected to the filter holding plate 9h1 as described above. The long hole 9h11 is fitted.
[0108]
Therefore, when the ND drive motor 9f rotates and the ND drive arm 9g swings, the ND filter unit 9h reciprocates in the direction of the arrow 9h14 in FIG. 5 while the elongated holes 9h12 and 9h13 are guided by the guide pin 9a4. To do. Thereby, each ND area 9h7-9h9 can be advanced / retreated with respect to the aperture opening formed by the aperture blade 9e.
[0109]
At this time, as shown in FIG. 5, the direction of the arrow 9h14 which is the forward / backward direction of the ND filter unit 9h is inclined obliquely with respect to the vertical axis V (short side 18a), and the ND drive motor 9f is When viewed from the optical axis direction, Position close to vertical axis V ND filter unit 9h It is laid out below.
[0110]
For this reason, when the ND filter unit 9h is driven forward and backward, the distal end portion (pin portion 9g1) of the ND drive arm 9g is located at the position indicated by 9g11 in the drawing at the retracting direction end and at the position indicated by 9g13 at the approaching direction end. Will be located. The exact center of the entire swing angle of the ND drive lever 9g is 9g12.
[0111]
When the filter drive mechanism including the ND filter unit 9h has such a layout, the filter drive mechanism can be prevented from being enlarged only in one direction (for example, the vertical direction) in the plane orthogonal to the optical axis.
[0112]
The reason for this is that when the pin portion 9g1 of the ND drive arm 9g is positioned at the distribution center 9g12 of all the swing angles, the horizontal axis H and the ND drive arm 9g The angle 9g2 formed by is a certain angle rather than 0 ° with respect to the horizontal axis H, and the ND in the direction of the vertical axis V even when the pin portion 9g1 of the ND drive arm 9g reaches the position 9g11 farthest from the optical axis. This is because it is located on the upper side (optical axis side) of the horizontal line 9f1 passing through the lowermost end of the drive motor 9f.
[0113]
Further, as in the present embodiment, by arranging the motors 9b and 9f on the opposite sides of the base plate 9a, for example, the motors 9b and 9f are distributed and arranged on one side of the base plate 9a. Compared to the case, the vertical dimension of the entire light quantity adjustment unit can be reduced.
[0114]
Further, since the line representing the distribution center angle 9g2 of the swing angle is substantially orthogonal to the forward / backward drive direction 9h14 of the ND filter unit 9h, the total swing angle of the ND drive arm 9g is set to the full forward / backward stroke of the ND filter unit 9h. It can be used effectively.
[0115]
At this time, the most advanced portion 9h4 and density boundary portions 9h5 and 9h6 of the ND area 9h7 are substantially parallel to the horizontal axis H.
[0116]
This is because, when the most advanced portion 9h4 and density boundary portions 9h5 and 9h6 of the ND area 9h7 have an angle with respect to the horizontal axis, the image picked up by the image pickup device is, for example, a portion on the diagonal upper side of the screen when the ND filter enters This is because the image becomes darker and the high-quality image cannot be obtained.
[0117]
That is, if the forefront portion 9h4 and the density boundary portions 9h5 and 9h6 of the ND area 9h7 are parallel to the horizontal axis, for example, when entering the ND filter, it becomes dark from the upper side of the imaging screen. In many cases, the upper side of the screen is brighter than the lower side of the screen (for example, in landscape photography, the upper side of the screen is empty and bright).
[0118]
In the present embodiment, a ground plate 9a is disposed between the diaphragm blade 9e and the ND filter unit 9h, and the working space of the diaphragm blade 9e and the working space of the ND filter unit 9h are partitioned by the ground plate 9a. Therefore, the aperture blade 9e and the ND filter unit 9h do not interfere with each other. For this reason, each smooth operation of the aperture blade 9e and the ND filter unit 9h can be ensured.
[0119]
Furthermore, the thickness of the light amount adjusting unit 9 of the present embodiment excluding the drive motors 9b and 9f (particularly before and after the ring-shaped portion of the ground plane 9a) in the optical axis direction is such that the drive ring 9d is in the ring shape of the ground plane 9a. Since it falls within the thickness of the portion, the thickness of the ring-shaped portion of the base plate 9a, the thickness of the working space of the diaphragm blade 9e, the thickness of the working space of the ND filter unit 9h, and the thickness of the front and rear pressing plates 9i, 9j For example, the driving ring can be arranged on the outer side in the optical axis direction of the ground plane, and in addition to this, it can be made thinner than the case where a partition plate is provided separately from the ground plane.
[0120]
Further, since the ND filter unit 9h is located on the opposite side of the ND drive motor 9f with the ground plate 9a interposed in the optical axis direction, the ground plate 9a and the ND drive lever are interposed between the ND filter unit 9h and the ND drive motor 9f. 9g can be laid out. Conventionally, in the optical axis direction, the ND filter unit 9h, the ND drive lever 9g, and the ND drive motor 9f are laid out only on one side with respect to the ground plane 9a. Contributes to space saving in the direction.
[0121]
Further, since the diaphragm blade 9e is located on the opposite side of the diaphragm drive motor 9b with the ground plate 9a in the optical axis direction, the ground plate 9a and the diaphragm drive lever 9c are laid out between the diaphragm blade 9e and the diaphragm drive motor 9b. Conventionally, the diaphragm blades 9e, the diaphragm drive lever 9c, and the diaphragm drive motor 9b are laid out only on one side of the base plate 9a in the optical axis direction, but space saving in the optical axis direction is possible. Contributing to
[0122]
FIG. 6 shows an electrical configuration of a video camera (imaging device) provided with the photographing lens barrel. In this figure, the components of the lens barrel described with reference to FIGS. 1 to 5 are given the same reference numerals as those in these drawings and are not described.
[0123]
In FIG. 6, reference numeral 61 denotes a control circuit composed of a CPU. In the stepping motor stator unit 13 and the lead screw 12 as a zoom drive source, the stepping motor stator unit 11 and the lead screw 10 as a focus drive source, and the shift unit 3. Each drive source such as the coil 3i, the aperture drive motor 9b, and the ND drive motor 9f is controlled, and each circuit and the like described later are controlled.
[0124]
Further, the control circuit 61 includes zoom and focus reset switches 15 and 14, a shake sensor 63 that detects camera shake and drives the shift unit 3, shift position sensors 3 e and 3 g, a diaphragm mechanism in the light amount adjustment unit 9, and ND A detection signal from the aperture / ND reset switch 62 for detecting that the filter unit is located at the initial position is input.
[0125]
For the zoom drive source, the focus drive source, the aperture drive motor 9b, and the ND drive motor 9f, the drive pulses supplied to the drive sources are counted from the time when the initial positions are detected by the reset switches 15, 14, and 62. By doing so, position detection is performed or driving to a target position is performed.
[0126]
A camera signal processing circuit 65 performs predetermined amplification, gamma correction, and the like on the output of the image sensor 18. The contrast signal of the video signal subjected to these predetermined processes passes through the AE gate 66 and the AF gate 67. That is, an optimum signal extraction range for determining the target position and shutter speed of the aperture and ND filter unit (exposure determination) and focusing is set in this gate in the entire screen. The size of the gate may be variable or a plurality of gates may be provided.
[0127]
Reference numeral 68 denotes an AF signal processing circuit that processes an AF signal for AF (autofocus), and generates one or a plurality of outputs related to high-frequency components of the video signal.
[0128]
Reference numeral 70 denotes a zoom switch operated by a photographer, and reference numeral 69 denotes a zoom tracking memory. The zoom tracking memory 69 stores information on the focusing lens position to be set according to the subject distance and the variator lens position at the time of zooming. Note that the memory in the CPU 61 may be used as the zoom tracking memory.
[0129]
For example, when the photographer operates the zoom switch 70, the CPU 61 maintains a predetermined positional relationship between the second group lens L2 and the fourth group lens L4 calculated based on information in the zoom tracking memory 69. The zoom drive source and the focus drive source are driven and controlled.
[0130]
In the autofocus operation, the CPU 61 drives and controls the focus drive source so that the output of the AF signal processing circuit 68 shows a peak.
[0131]
Further, in order to obtain an appropriate exposure, the CPU 61 drives and controls the aperture drive motor 9b and the ND drive motor 9f with the average value of the output of the Y signal that has passed through the AE gate 66 as a predetermined value, so that the aperture opening diameter and the ND Control transmission.
[0132]
Here, a light amount adjustment method by the control circuit 61 from the initial state in which the aperture in the present embodiment is open and the ND filter is retracted will be described.
[0133]
The control circuit 61 adjusts the amount of light only by closing the diaphragm from the initial state to the brightness (darkness) of F4.0, for example. This is because image degradation due to diffraction does not occur even when the aperture is closed up to about F4.0.
[0134]
And when darkening to F4.0 or more, the control circuit 61 performs light quantity adjustment by the ND filter.
[0135]
By adopting such a control method, the range through which the light beam of the ND filter unit 9h passes can be reduced to about the aperture diameter of F4.0, and the ND filter unit 9h and thus the light quantity adjustment unit 9 can be downsized. Can do.
[0136]
Note that the boundary between the light amount adjustment by the diaphragm and the light amount adjustment by the ND filter does not have to be F4.0, and this value may be on the smaller diaphragm side as long as the influence of diffraction does not occur.
[0137]
In this embodiment, the ND filter unit has three transmittance areas. (Multiple concentration areas) However, the number thereof may be one or two transmittance areas or four or more transmittance areas.
[0138]
Further, the method of forming the plurality of transmittance areas may not be the method described in the above embodiment, but two single density filters may be combined, or a filter having two or more types of transmittance may be used. You can just paste one.
[0139]
Further, the density of the plurality of transmittance areas described in the present embodiment is merely an example, and the transmittance of each transmittance area is set so that the transmittance increases (the density decreases) toward the front end side of the ND filter in the approach direction. Should be set.
[0140]
(Second Embodiment)
7 and 8 show the configuration of the light amount adjustment unit 9 according to the second embodiment of the present invention. Since the basic configuration of this embodiment is the same as that of the first embodiment, common constituent elements are denoted by the same reference numerals. Since the opening / closing mechanism of the ND filter is exactly the same as that of the first embodiment, only the opening / closing mechanism of the diaphragm blade will be described here with reference to FIGS.
[0141]
FIG. 7 is an exploded perspective view of the light quantity adjusting unit 9 ′, and FIG. 8 is a main sectional view thereof.
[0142]
Here, in each of the two diaphragm blades 9k, in addition to the hole 9k1 that fits the projection 9a2 provided at two places on the diaphragm base 9a, there is a long hole 9k2 that fits the diaphragm drive lever 9c. Is formed.
[0143]
When the diaphragm drive lever 9c connected to the output shaft of the diaphragm drive actuator 9b rotates, each of the two diaphragm blades 9k pivots around the protrusion 9a2 to change the opening diameter formed by the diaphragm blade 9k. Then, the amount of light is adjusted.
[0144]
The aperture blade 9k is located on the opposite side of the aperture drive motor 9b across the base plate 9a in the optical axis direction. By doing in this way, the base plate 9a and the aperture drive lever 9c can be laid out between the aperture blade 9k and the aperture drive motor 9b. Conventionally, the diaphragm blades 9k, the diaphragm drive lever 9c, and the diaphragm drive motor 9b are laid out only on one side of the base plate 9a in the optical axis direction, but space saving in the optical axis direction can be achieved. it can.
[0145]
【The invention's effect】
As described above, according to the first invention of the present application, the light shielding blade is Rotate In addition to having a blade mechanism in which the light passage opening is not easily deformed even in a small aperture state of the type, the support plate itself such as the base plate can prevent interference between the light shielding blade and the ND filter, and can ensure smooth operation of the light shielding blade and the ND filter. In addition, by arranging the first and second actuators on opposite sides of the support plate, the dimensions in the direction perpendicular to the optical axis are compared with the case where the first and second actuators are arranged on both sides in the direction perpendicular to the optical axis. Therefore, it is possible to realize a light amount adjusting device with a small amount.
[0146]
In addition, according to the second invention of the present application, a plurality of light shielding blades are rotated by rotation of the drive ring. Rotation In addition to having a blade drive mechanism that makes it difficult for the light passage aperture to be deformed even in a small aperture state, the support plate such as the base plate itself prevents interference between the light shielding blade and the ND filter and ensures smooth operation of the light shielding blade and the ND filter. In addition, by disposing the drive ring within the thickness in the optical axis direction of the support plate, the ND filter driven separately from the light shielding blade is provided, but the thickness in the optical axis direction is thin, and further, the first and second actuators are provided. By arranging the support plates on opposite sides of each other, a light amount adjusting device having a smaller dimension in the direction perpendicular to the optical axis than in the case where the first and second actuators are arranged on both sides in the direction perpendicular to the optical axis is realized. Can do.
[0147]
In the first and second aspects of the invention, if the first actuator is disposed on the side opposite to the light shielding blade or the blade driving mechanism (that is, the ND filter side) with the support plate interposed therebetween, Since the diaphragm drive lever and the support plate are arranged between the actuator 1 and the diaphragm blade, conventionally, the diaphragm blade, the diaphragm drive lever, and the first actuator are arranged only on one side in the optical axis direction with respect to the support plate. In contrast to the layout, space saving in the optical axis direction can be achieved.
[0148]
Further, by disposing the second actuator on the opposite side of the ND filter (that is, on the light shielding blade or blade driving mechanism side) with the support plate in between, the second actuator and the ND filter are arranged in the optical axis direction. Since the ND drive lever and the support plate are disposed between them, conventionally, an ND filter is provided only on one side in the optical axis direction with respect to the support plate. ND In contrast to the layout of the drive lever and the second actuator, space saving in the optical axis direction can be achieved.
[0149]
In addition, when using an ND filter having a plurality of transmission regions with different densities, if a transmission region with a lower concentration is arranged on the front side in the approach direction to the position overlapping the light passage port in the ND filter, It is possible to prevent the influence of diffraction due to a large difference in transmittance between the through portion at the passage opening and the portion where the ND filter overlaps.
[0150]
Further, in a photographing lens barrel that includes the light amount adjusting device and forms an image on a rectangular image pickup device through the light amount adjusting device, the forward / backward driving direction of the ND filter is inclined with respect to the side of the image pickup device. For example, the size of the ND filter driving range in the direction in which the side extends can be reduced, and the light amount adjusting device can be prevented from being enlarged only in any one direction perpendicular to the optical axis.
[0151]
Further, when the arm member is driven to swing by the second actuator, and the ND filter is moved forward and backward by this arm member, the swing range of the arm member is set in the direction in which the side of the image sensor in the second actuator is extended. If it is within the optical axis side of the end, the dimension of the entire device in the direction in which the side extends can be further reduced.
[0152]
By using such a photographing lens barrel, it is possible to reduce the size of the imaging apparatus.
[0153]
Even when the forward / backward driving direction of the ND filter is oblique as described above, if the leading edge of the ND filter and the density boundary line in the ND filter are made substantially parallel to the upper side of the image sensor, It is possible to prevent a sense of incongruity from occurring in the brightness change in the imaging screen during advance and retreat.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a photographic lens barrel provided with a light amount adjustment unit according to a first embodiment of the present invention.
FIG. 2 is a main cross-sectional view of the entire photographing lens barrel.
FIG. 3 is an exploded perspective view of the light amount adjustment unit.
FIG. 4 is a cross-sectional view of the light quantity adjustment unit.
FIG. 5 is a diagram of an ND drive mechanism of the light quantity adjustment unit as viewed from the image plane side.
FIG. 6 is a configuration diagram of an electric circuit of a video camera provided with the photographing lens barrel.
FIG. 7 is an exploded perspective view of a light amount adjustment unit according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view of the light amount adjustment unit of the second embodiment.
FIG. 9 is a sectional view of a conventional lens barrel for a video camera.
FIG. 10 is a configuration diagram of a conventional diaphragm device.
FIG. 11 is a configuration diagram of a conventional diaphragm device.
[Explanation of symbols]
1 Front lens barrel unit
2 Scaling frame
3 Shift unit
4 Focus movement frame
5 Rear barrel
6, 7, 8 Guide bar
9,9 'Light intensity adjustment unit
9a Ground plate
9b Aperture drive motor
9d drive ring
9e, 9k aperture blade
9f ND drive motor
9h ND filter unit
10 Lead screw
11 Stepping motor stator unit
12 Lead screw
13 Stepping motor stator unit
14, 15, 62 Reset sensor

Claims (7)

A plurality of light shielding blades that form a light passage opening by an outer edge having a curvature, and change an opening area of the light passage opening by rotation, a first actuator for driving the plurality of light shielding blades, and the light passage a light amount adjusting device having a ND filter for forward and backward relative to the position overlapping in the optical axis direction to the mouth, and a second actuator for advancing and retracting driving the ND filter,
A first arm extending in the optical axis direction is attached to the output shaft of the first actuator, and the first arm is driven to swing in the plane orthogonal to the optical axis by the first actuator. Is connected to the plurality of light shielding blades,
A second arm extending in the optical axis direction is attached to the output shaft of the second actuator, and the second arm is driven to swing in the plane orthogonal to the optical axis by the second actuator. And coupled to the ND filter,
In the optical axis direction, a support plate for supporting the plurality of light shielding blades and the ND filter is disposed between the plurality of light shielding blades and the ND filter,
In the optical axis direction, the first actuator is disposed on the opposite side of the light shielding blade with the support plate in between, and the second actuator is disposed on the opposite side of the ND filter with the support plate in between. Has been
The light amount adjusting device , wherein the first arm and the second arm are arranged in a position overlapping in the optical axis direction . A plurality of light shielding blades that form a light passage opening by an outer edge having a curvature, and a blade driving mechanism that rotates the plurality of light shielding blades by a drive ring that rotates around the optical axis to change the opening area of the light passage opening. a first actuator for rotating the drive ring, and the ND filter for forward and backward relative to the position overlapping in the optical axis direction to the optical passage port, a second actuator for advancing and retracting driving the ND filter, A light quantity adjusting device having
A first arm extending in the optical axis direction is attached to the output shaft of the first actuator, and the first arm is driven to swing in the plane orthogonal to the optical axis by the first actuator. Connected to the drive ring,
A second arm extending in the optical axis direction is attached to the output shaft of the second actuator, and the second arm is driven to swing in the plane orthogonal to the optical axis by the second actuator. And coupled to the ND filter,
In the optical axis direction, a support plate for supporting the blade driving mechanism and the ND filter is disposed between the blade driving mechanism and the ND filter,
In the optical axis direction, the first actuator is disposed on the opposite side of the blade drive mechanism with the support plate in between, and the second actuator is disposed on the opposite side of the ND filter with the support plate in between. Has been placed ,
The light amount adjusting device , wherein the first arm and the second arm are arranged in a position overlapping in the optical axis direction . The ND filter has a plurality of transmission regions each having a different density,
Light amount adjustment according to claim 1 or 2, characterized in that the concentration of the thin transmissive region of the plurality of transmission regions as the entering direction leading end side to the position overlapping the light passage opening is disposed in said ND filter apparatus. A photographic lens barrel including the light amount adjusting device according to any one of claims 1 to 3 and forming an image on a rectangular imaging device through the light amount adjusting device,
When viewed from the optical axis direction, forward and backward driving direction of the ND filter, the photographing lens barrel, characterized in that is tilted with respect to the sides of the image sensor. The photographing lens barrel according to claim 4 , wherein the front end edge of the ND filter in the approach direction with respect to the light passage port extends substantially parallel to the upper side of the image sensor. The ND filter has a plurality of density regions, and a leading edge in an approach direction with respect to the light passage port and density boundary lines in the plurality of density regions of the ND filter are substantially parallel to an upper side of the imaging element. The photographic lens barrel according to claim 4 , wherein the photographic lens barrel extends in a vertical direction. An imaging apparatus comprising the photographic lens barrel according to any one of claims 4 to 6 .

Images