JP3740445B2 - Light amount adjusting device, optical device, and imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light amount adjusting device arranged in a lens barrel used in an imaging device such as a camera, a video camera, or a digital still camera.
[0002]
[Prior art]
Cameras such as video cameras and digital cameras with a built-in solid-state image sensor, and ordinary cameras that use photographic film adjust the focal depth of the lens and adjust the amount of light in the field formed on the film or solid-state image sensor. In order to adjust, a diaphragm device (light amount adjusting device) for controlling the size of the exposure aperture is provided.
[0003]
Currently, the diaphragm devices that are generally used in many cases use a plurality of diaphragm blades as a light shielding member, and the type in which the aperture diameter is continuously changed around the optical axis like an iris, and two diaphragm blades There is known a type in which the aperture diameter is changed by substantially parallel-shifting in the opposite directions.
[0004]
The former type has the advantage that an arbitrary opening diameter can be obtained because the opening diameter can be continuously changed. However, in order to obtain an opening having a shape close to a circle, the number of aperture blades must be reduced. Since there is a need to increase it, there is a disadvantage that the cost becomes high.
[0005]
On the other hand, the latter type is advantageous in terms of cost because the number of diaphragm blades is small, but has a drawback that the shape of the opening differs depending on the opening area, and a shape close to a uniform circle cannot be obtained.
[0006]
Further, a technique is known in which an optical filter called an ND filter (attenuating filter) is combined with the above-described aperture device so that the amount of light in the object field can be controlled in multiple steps as compared with the case of only aperture blades.
[0007]
Further, as a camera exposure control mechanism, there is a shutter device in addition to the aperture device. The shutter device is roughly divided into a focal plane shutter and a lens shutter. However, when the diaphragm device is provided in a camera with a lens shutter, the diaphragm device is disposed adjacent to the lens shutter. The challenge is how to make these devices compact and how they can be manufactured at low cost.
[0008]
In particular, recently, since the shutter blades are opened and closed by an actuator, such a requirement is extremely high.
[0009]
[Problems to be solved by the invention]
However, in the conventional diaphragm device, the diaphragm blade actuator and the neutral density filter actuator are generally provided separately. Furthermore, when the shutter blades are driven by actuators, a total of three actuators are required, and the structural part related to light amount adjustment becomes large, and the camera and lens barrel on which the shutters are mounted become large and the cost increases. End up.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a light amount adjusting device that can reduce the size and cost of an apparatus by combining an actuator that drives a light shielding member such as a diaphragm blade or a shutter blade that also serves as an aperture and an actuator that drives an optical filter. It is said.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, in a light amount adjusting device having an actuator and a light shielding member that is driven to open and close by the actuator, an optical that can be inserted into and retracted from the optical path independently of the light shielding member. Filters, A filter holding member for holding an optical filter; A drive mechanism for moving the optical filter by at least one of the operation in the further opening direction of the actuator that has driven the light shielding member to the open position and the operation in the further fully closed direction of the actuator that has driven the light shielding member to the fully closed position; Have The drive mechanism includes a rotating member that is driven to rotate about the optical axis by the actuator, and the rotating member is in contact with the light holding member driving unit that opens and closes the light shielding member, and the filter holding member to insert the optical filter. A filter driving unit for retreating and a filter movement preventing unit for preventing movement of the optical filter in the insertion direction and the retraction direction by contact with the filter holding member while driving the light shielding member to open and close A light quantity adjusting device characterized by that.
[0012]
Specifically, for example, the light-reducing filter is inserted into or retracted from the optical path by an operation in the further opening direction of the actuator that drives the light-shielding member (aperture blade or diaphragm shutter blade) to the open position, or the light-shielding member. The optical filter is retracted or inserted into the optical path by further movement of the actuator that has been driven to the fully closed position in the fully closed direction.
[0013]
As a result, the light shielding member and the optical filter can be driven by a single actuator, and the light amount adjusting device including the optical filter can be reduced in size and cost.
[0014]
Here, particularly when the shutter function is combined with the aperture function, the actuator that has driven the light shielding member to the open position is further driven by a predetermined amount in the open direction to start insertion or retraction movement of the optical filter with respect to the optical path. A mechanism may be configured. Further, the drive mechanism may be configured so that the actuator that drives the light shielding member to the fully closed position further moves a predetermined amount in the fully closed direction to start retraction or insertion movement of the optical filter with respect to the optical path.
[0015]
Since the light-shielding member used as the shutter blade is driven at a high speed, the open position or the fully closed position may be exceeded by the so-called overshoot when it is opened or fully closed. By providing a predetermined amount of margin as described above, it is possible to prevent the optical filter from moving due to the overshoot.
[0016]
Furthermore, in order to reliably prevent unnecessary movement to the optical filter due to such overshoot, the driving speed of the actuator when moving the optical filter is driven between the open position and the fully closed position. It is preferable to provide a control means for controlling the actuator so as to be slower than the driving speed of the actuator at the time.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
15 and FIGS. 1 to 5 show the configuration and operation of the light amount adjusting apparatus 100 according to the first embodiment of the present invention. FIG. 15 is an exploded perspective view of the light amount adjusting device, FIG. 1 is a view showing a state where an aperture / shutter blade (hereinafter simply referred to as an aperture blade) is in the open position, and the ND filter is retracted from the optical path, FIG. It is a figure which shows the cross section of the perpendicular direction of the light quantity adjustment apparatus shown in FIG. 3 is a view showing a state in which the windmill member is rotated from the state shown in FIG. 1 and the diaphragm blades are squeezed to the fully closed position, and FIG. 4 is a state in which the windmill member is further rotated from the state shown in FIG. FIG. 5 is a diagram showing a rotated state, and FIG. 5 is a diagram showing a state in which the wind turbine member is rotated from the state shown in FIG. 1 and an ND filter is inserted into the optical path.
[0018]
In these drawings, reference numeral 101 denotes a ground plate serving as a main body of the light amount adjusting device 100, and a fixed opening 101b is formed at the center of the ground plate 101. Reference numeral 102 denotes a partition plate attached to the main plate 101, and reference numeral 103 denotes a windmill member (rotating member) disposed so as to be sandwiched between the main plate 101 and the partition plate 102. The windmill member 103 has a cylindrical portion at the center thereof. The outer periphery of 103 g is fitted to the inner periphery of a fixed opening 102 b formed at the center of the partition plate 102 and is held rotatably about the optical axis L.
[0019]
Reference numeral 104 denotes a diaphragm blade (light-shielding member) disposed in a space between the base plate 101 and the windmill member 103. In the present embodiment, six diaphragm blades 104 having the same shape are used. Note that the number of aperture blades is not limited to six and may be any other number. Hole portions 104a are formed at the base end portions of the respective aperture blades 104, and fixed pin portions 101g provided on the base plate 101 are fitted into the hole portions 104a, and each aperture blade 104 has the fixed pin portion 101g. It is rotatably supported at the center.
[0020]
Reference numeral 106 denotes a cam pin that is crimped to the diaphragm blade 104 and engages with a cam groove portion (light shielding member driving portion) 103 a formed in the wind turbine member 103. As a result, when the windmill member 103 rotates, the cam pin 106 moves along the cam groove portion 103a, whereby the aperture blade 104 rotates between the open position and the closed (fully closed) position around the fixed pin portion 101g. . When all the six diaphragm blades 104 are rotated in the same manner, the diameter of the diaphragm aperture formed by these six diaphragm blades 104 changes.
[0021]
Reference numeral 107 denotes a pressing plate fixed to the base plate 101 with the partition plate 102 interposed therebetween, and 108 denotes a filter holding frame arranged so as to be sandwiched between the partition plate 102 and the pressing plate 107. A filter rotation shaft 110 is caulked at the base end portion of the filter holding frame 108, and the filter rotation shaft 110 is fitted in a hole 102 a formed in the partition plate 102. The filter holding frame 108 can rotate around the rotation shaft 110.
[0022]
Reference numeral 109 denotes an ND filter attached to the front end side of the filter holding frame 108, which attenuates the amount of light transmitted through the filter by having a predetermined transmittance (density).
[0023]
Reference numeral 111 denotes a one-sided spring comprising a torsion coil spring, and the coil portion is attached to a spring holding shaft 101 a provided on the base plate 101.
Reference numeral 112 denotes a shift pin that is crimped to the filter holding frame 108. When the filter holding frame 108 (ND filter 109) is in a position where the filter holding frame 108 (ND filter 109) is inserted into the optical path (hereinafter, referred to as an insertion position), the biasing pin 112 is a base plate of the two arms of the biasing spring 111. Abutting on the distal end side of the bent portion of one arm portion (an arm portion bent at an obtuse angle in the middle) that abuts on a spring bearing shaft 101d provided on 101, the filter holding frame 108 is in a state of being shifted to this insertion position Hold with.
[0024]
Further, when the filter holding frame 108 (ND filter 109) is at a position (hereinafter referred to as a retracted position) where the filter holding frame 108 (ND filter 109) is retracted from the optical path, it is closer to the proximal end than the bent portion of the one arm portion. In contact with each other, the filter holding frame 108 is held in the retracted position in a shifted state.
[0025]
Note that the other arm portion of the one-sided spring 111 is in contact with a spring receiving shaft 101 c provided on the main plate 101.
[0026]
113 is a stepping motor (actuator). Reference numeral 114 denotes an output pinion of the stepping motor 113, which meshes with a windmill gear portion 103 b formed on a part of the outer periphery of the windmill member 103.
[0027]
Reference numeral 115 denotes a rotation pin attached to the filter holding frame 108. The filter holding frame 108 is driven to rotate about the filter rotation shaft 110 by the rotation pin 115 being pushed by the insertion protrusion 103 c and the retracting protrusion 103 d (filter driving portion) formed on the windmill member 103. Further, the rotating pin 115 abuts (slidably contacts) the outer periphery of an arcuate protrusion (filter movement preventing part) 103e formed between the insertion protrusion 103c and the retracting protrusion 103d in the windmill member 103, and the filter It also has a role of preventing the rotation of the filter holding frame 108 except during insertion and retraction.
[0028]
1-5, the circle drawn on the center line of the cam groove 103a of the windmill member 103 moves within the cam groove 103a every time the windmill member 103 is driven by one step by the stepping motor 113. The position of the cam pin 106 of the aperture blade 104 is shown. The state shown in FIG. 1 where the cam pin 106 is located at the position D in the cam groove 103a is the open state, and the state shown in FIG. 3 where the cam pin 106 is located at the position E is the closed state.
[0029]
When the windmill member 103 rotates from the open state shown in FIG. 1 in the direction opposite to the A direction (that is, in the open direction) in the drawing, and the cam pin 106 moves in the section C to B of the cam groove 103a. The filter holding frame 108 rotates in the counterclockwise direction in the drawing around the filter rotation shaft 110 when the rotation pin 115 is pushed by the insertion protrusion 103 c of the windmill member 103. Thereby, as shown in FIG. 5, the ND filter 109 is inserted into the optical path.
[0030]
In the section C and B, there is no lift change in the wind turbine member radial direction of the cam groove portion 103a, so that the aperture blade 104 is held in the open position (the same position as the cam pin 106 is in the D position).
[0031]
As shown in FIG. 3, when the cam pin 106 moves within the interval between D and E of the cam groove 103a, the aperture blade 104 opens and closes to change the aperture diameter, thereby adjusting the amount of light passing through the aperture. it can.
[0032]
For example, the position where the stepping motor 113 has rotated four steps from the position D is the position “F4”, which is a position narrowed by one step from the open position. The position further rotated by two steps is a position further narrowed by “F5.6”. When further rotated by two steps, “F8”, “F11”, and “F16” are reduced step by step. The position where the stepping motor 113 rotates four steps from the position “F16” is the closed position where the diaphragm blades 104 are completely closed.
[0033]
As described above, the aperture changes step by step in two steps of the stepping motor 113 between “F4” and “F16”, and there is a 4-step interval between the open and “F4”. This is because the cam groove 103a has a gentle curve so that the aperture blade 104 does not spread outward (ie, the aperture blade 104 is maintained in the open position) in the open direction (C, B) further from “open”. If the cam groove 103a is formed with a sharp curve between the open position and "F4", the movement of the aperture blade 104 in the region before and after the open position (D) becomes worse. Therefore, an interval of 4 steps is provided between the opening and “F4” so that a large curvature can be obtained in the region before and after the opening of the cam groove 103a.
[0034]
In addition, even between “F16” and the closed position, if this is set to two steps, the curvature of the cam groove portion 103a is reduced, and the movement of the diaphragm blade 104 is deteriorated. Therefore, an interval of four steps is taken. The curvature is increased.
[0035]
In the section between D and C, when the windmill member 103 is rotated from the closed side toward the open position D at high speed, the windmill member 103 and the cam pin 106 overshoot beyond the open position D. This is also a rotation margin region (a predetermined amount of region referred to in the claims) for preventing the filter holding frame 108 (the rotation pin 115) from being pushed by the insertion protrusion 103c and moving in the insertion direction.
[0036]
Further, when the windmill member 103 rotates in the direction A (closed direction) from the open mechanical end position shown in FIG. 5 and the cam pin 106 moves in the section from F to G of the cam groove portion 103a, the filter holding frame The rotation pin 115 is pushed by the retracting projection 103 d of the windmill member 103 and rotates about the filter rotation shaft 110 in the clockwise direction in FIG. Thereby, as shown in FIG. 4, the ND filter 109 retracts out of the optical path.
[0037]
In the section between F and G, there is no lift change in the wind turbine member radial direction of the cam groove portion 103a, so that the aperture blade 104 is held in the closed position (the same position as the cam pin 106 is in the E position). The
[0038]
In the section between E and F, when the windmill member 103 is rotated from the open side to the close position E at high speed, the windmill member 103 and the cam pin 106 overshoot beyond the close position E. This is also a rotation allowance region (a predetermined amount of region referred to in the claims) for preventing the filter holding frame 108 (the rotation pin 115) from being pushed by the retracting projection 103d and moving in the retracting direction.
[0039]
Further, when the filter holding frame 108 (the rotation pin 115) is pushed and rotated by the insertion protrusion 103c and the retracting protrusion 103d, the rotation pin 115 is slightly displaced in the radial direction of the windmill member 103. Concave portions 103f for escaping from the displacement of the rotating pin 115 are formed at both ends in the circumferential direction of 103e.
[0040]
The light quantity adjustment device 100 configured as described above is mounted in, for example, the photographing optical system of the digital still camera 160 shown in FIG. In FIG. 16, reference numeral 150 denotes a photographing lens that constitutes a photographing optical system together with the light amount adjusting device 100. Reference numeral 140 denotes an image sensor such as a CCD or CMOS that photoelectrically converts a subject image formed by the photographing optical system. An image signal obtained by photoelectric conversion of the image sensor 140 is subjected to predetermined processing by a signal processing circuit (not shown) and then recorded in a recording medium (semiconductor memory or the like) (not shown). Note that the light amount adjusting device of the present embodiment can be mounted not only on such a digital still camera but also on a video camera, a film camera, and an interchangeable lens device (optical device) of these cameras.
[0041]
Next, the control operation (from initial setting to photographing operation) of the light quantity adjusting device will be described with reference to FIG. This control operation is performed when the stepping motor 113 is controlled by the control circuit 120 (or a diaphragm adjustment control circuit) mounted on the camera. First, when power is supplied to the camera and control circuit 120, the windmill member 103 (aperture blade 104) and the filter holding frame 108 are in the positions where they were stopped last time.
[0042]
(Step 1)
As an initial operation, the control circuit 120 rotates the stepping motor 113 to rotate the windmill member 103 beyond the maximum rotation angle in the direction of arrow A shown in FIGS. 1 to 5 (for example, by rotating the stepping motor 113 by 44 steps). ), The stepping motor 113 is stopped by the energization status where the cam pin 106 comes to the position G of the cam groove 103a. As a result, as shown in FIG. 4, the diaphragm blade 104 is in the closed position, and the retracting projection 103d pushes the rotation pin 115, so that the filter holding frame 108 is in the retracted position.
[0043]
(Step 2)
Next, the control circuit 120 rotates the stepping motor 113 at a high speed so that the cam pin 106 reaches the position D, and rotates the windmill member 103 at a high speed in the direction opposite to the arrow A direction. When the windmill member 103 is rotated at a high speed so that the cam pin 106 is located at the position D in this way, the windmill member 103 overshoots to a position where the cam pin 106 passes the position D, but the windmill member is placed on the rotation pin 115 of the filter holding frame 108. Since there is a margin of 4 steps until the insertion protrusion 103c provided on 103 hits (until the cam pin 106 reaches the position C), the insertion protrusion 103c does not hit the rotation pin 115. For this reason, the filter holding frame 108 is not inserted into the optical path.
[0044]
Then, as shown in FIG. 1, the diaphragm blade 104 reaches the open position, and the filter holding frame 108 is biased to the retracted position by the bias spring 111. Thereby, the initial position setting is completed.
[0045]
(Step 3)
The control circuit 120 determines whether or not to insert the ND filter 109 into the optical path based on information such as subject luminance measured by the camera, and if so, proceeds to step 4 to perform a filter insertion operation. When the ND filter 109 is not inserted into the optical path, the process proceeds to step 6 to set the aperture diameter.
[0046]
(Step 4)
Here, the ND filter 109 is inserted. The control circuit 120 rotates the stepping motor 113 to rotate the windmill 103 by 13 steps in the direction opposite to the arrow A so that the cam pin 106 reaches the position B as shown in FIG. As a result, the rotation pin 115 is pushed by the retracting projection 103c of the windmill member 103, the filter holding frame 108 rotates, and the ND filter 109 is inserted into the optical path.
[0047]
(Step 5)
The control circuit 120 rotates the stepping motor 113 and rotates the windmill member 103 in the direction of arrow A by 13 steps. As a result, the aperture blade 104 is positioned at the open position (the cam pin 106 is at the D position), and the ND filter 109 is shifted to the insertion position by the biasing spring 111. Thus, the filter insertion operation is completed.
[0048]
(Step 6)
Next, the aperture opening formed by the aperture blade 104 is set to an optimum aperture diameter based on the photometric result or the like. That is, the control circuit 120 drives the stepping motor 113 to rotate the windmill member 103 so that the cam pin 106 moves within the range of the position “F16” from the D position, and sets the aperture opening to the optimum opening diameter. To do. (Step 7)
Next, a shutter operation is performed. The stepping motor 113 is rotated at a high speed so that the cam pin 106 comes to the position E (closed position) from the state in which the aperture blade 104 forms the optimum opening diameter. Thereby, the shutter operation from the open state to the closed state is performed.
[0049]
At this time, even if the windmill member 103 (cam pin 106) overshoots beyond the E position, the retraction projection 103d provided on the windmill member 103 hits the rotation pin 115 of the filter holding frame 108 (the cam pin 106 is F). Since there is a margin of 4 steps until it reaches the position), the retracting projection 103d does not hit the rotating pin 115. For this reason, the filter holding frame 108 does not retract out of the optical path. This completes a series of initial settings to shooting operations.
[0050]
In this embodiment, when the rotation pin 115 is pushed by the insertion protrusion 103c and the retracting protrusion 103d, the filter holding frame 108 rotates, and the ND filter 109 is inserted into or retracted from the optical path. In the range to be changed, the insertion and retraction movement of the ND filter 109 are prevented by the rotation pin 115 coming into contact with the arc projection 103e. As a result, even if the biasing force of the biasing spring 111 is weakened, the ND filter 109 is not inadvertently moved due to vibration or the like within the range in which the aperture diameter of the diaphragm is changed, and the ND filter 109 is inserted and retracted. When it should be, the biasing force of the biasing spring 111 is weak and can be easily moved.
[0051]
Further, since the region from B to D and the region from F to G on the cam groove 103a for moving the ND filter 109 are displaced from each other in the radial direction of the windmill member 103, the cam grooves 103a adjacent in the circumferential direction are mutually connected. The rotation angle of the windmill member 103 can be widened without causing interference.
[0052]
Thereby, since the rotation angle of the windmill member 103 for inserting and retracting the ND filter 109 can be widened, the rotation pin 115 can be disposed at a position away from the filter rotation shaft 110 that is the rotation center of the filter holding frame 108. Therefore, the filter holding frame 108 can be inserted and retracted with a small force. This is effective for reducing the size of the stepping motor 113.
[0053]
In this embodiment, the ND filter 109 is inserted into the optical path by further rotating the stepping motor 113 in the opening direction from the open position, and the ND filter 109 is further rotated in the closing direction from the closed position. In the above description, the ND filter is retracted to the outside of the optical path by rotating the stepping motor further in the opening direction from the open position, and the stepping motor is further rotated in the closing direction from the closed position. Thus, the ND filter may be inserted into the optical path.
[0054]
(Second Embodiment)
7 to 10 show a configuration of a light amount adjusting device 200 according to the second embodiment of the present invention.
[0055]
FIG. 7 is a diagram showing a state in which a diaphragm / shutter blade (hereinafter simply referred to as a diaphragm blade) is in an open position, and the ND filter is retracted from the optical path. FIG. FIG. 9 is a diagram showing a state where the wind turbine member is further rotated from the state shown in FIG. 8 to the mechanical end, and FIG. 10 is a diagram showing the state where the wind turbine member is moved from the state shown in FIG. It is a figure which shows the state which rotated and inserted the ND filter in the optical path.
[0056]
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted. This embodiment is different from the first embodiment in that the arc projection 201e of the windmill member 201 is in contact with a pin 204 provided separately from the rotation pin 203 of the filter holding frame 202 on the inner peripheral side thereof. Is different.
[0057]
7-10, the windmill member 201 which has the cam groove part 201a and the gear part 201b similar to 1st Embodiment has the insertion projection part 201c, the retracting projection part 201d, and the circular arc projection part 201e. The roles of the insertion protrusion 201c, the retracting protrusion 201d, and the arc protrusion 201e are the same as in the first embodiment.
[0058]
Reference numeral 202 denotes a filter holding frame having a filter rotation shaft 110, a rotation pin 203, a pin 204, and a shift pin 112.
[0059]
The filter holding frame 202 (ND filter 109) rotates around the filter rotation shaft 110 when the windmill member 201 further rotates in the opening direction from the open position, and the insertion protrusion 201c pushes the rotation pin 203. Move to insert inside.
[0060]
Further, the filter holding frame 202 rotates around the filter rotation shaft 110 when the windmill member 201 further rotates in the closing direction from the closed position, and the retracting projection 201d pushes the rotation pin 203, and retracts out of the optical path. To do.
[0061]
Similarly to the first embodiment, when the aperture blade 104 is rotated to change the aperture opening diameter, the filter holding frame 202 does not rotate because the pin 204 comes into contact with the arc projection 201e. Thereby, unnecessary movement of the ND filter 109 in the light amount adjustment range by the diaphragm blades 104 is prevented.
[0062]
(Third embodiment)
FIGS. 11 to 14 show the configuration of a light amount adjusting device 300 according to the third embodiment of the present invention.
[0063]
FIG. 11 is a diagram showing a state in which a diaphragm / shutter blade (hereinafter simply referred to as a diaphragm blade) is in an open position, and the ND filter is retracted from the optical path, and FIG. 12 is a diagram showing that the windmill member rotates from the state shown in FIG. FIG. 13 is a view showing a state in which the windmill member is further rotated to the mechanical end from the state shown in FIG. 12, and FIG. 14 is a view showing the state in which the windmill member is moved from the state shown in FIG. It is a figure which shows the state which rotated and inserted the ND filter in the optical path.
[0064]
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted. This embodiment is different from the first embodiment in that a filter cam 301c is formed on the wind turbine member 301, and the filter cam 301c is used for insertion / retraction driving with respect to the optical path of the filter holding frame 302 and insertion / retraction other than during insertion / retraction driving. The difference is that the movement in the direction is blocked.
[0065]
11 to 14, reference numeral 301 denotes a windmill member having a cam groove portion 301a and a gear portion 301b similar to those in the first embodiment and having a filter cam 301c formed therein.
[0066]
As shown in FIGS. 11 to 14, the filter cam 301 c has a substantially rectangular shape, and is a cam formed by ribs provided on the inner side and the outer side.
[0067]
The filter holding frame 302 is provided with a filter rotation shaft 110, a rotation pin 303, and a biasing pin 112. The rotation pin 303 is engaged with a filter cam (filter drive unit and filter movement prevention unit) 301c. When the windmill member 301 further rotates in the opening direction from the open position, the rotation pin 303 is pushed by the filter cam 301c, whereby the filter holding frame 302 rotates around the filter rotation shaft 110 and the ND filter 109 is inserted and moved into the optical path. To do.
[0068]
When the windmill member 301 further rotates in the closing direction from the closed position, the rotation pin 303 is pushed by the filter cam 301c, whereby the filter holding frame 302 rotates around the filter rotation shaft 110, and the ND filter 109 moves out of the optical path. Move away.
[0069]
Similarly to the first embodiment, when the aperture blade 104 is rotated to change the aperture opening diameter, the rotation pin 303 is in contact with the arc-shaped portion of the filter cam 301c, so the filter holding frame 302 does not rotate. Thereby, unnecessary movement of the ND filter 109 in the light amount adjustment range by the diaphragm blades 104 is prevented.
[0070]
In each of the above-described embodiments, the case where the ND filter is inserted / retracted with respect to the optical path has been described. However, the present invention can be applied even when an optical filter other than the ND filter is used.
[0071]
Further, as the actuator, a motor other than the stepping motor can be used.
[0072]
【The invention's effect】
As described above, according to the present invention, the light shielding member and the optical filter can be driven by a single actuator, and the light amount adjusting device including the optical filter can be reduced in size and cost. .
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a state in which an ND filter is retracted in an opened state of a light amount adjusting device according to a first embodiment of the present invention.
2 is a view showing a surface showing a vertical cross section of the light amount adjusting device shown in FIG. 1; FIG.
FIG. 3 is a view showing a state where a wind turbine member is rotated from the state of FIG.
4 is a view showing a state in which a windmill member is rotated from the state of FIG. 3 to a mechanical end. FIG.
5 is a view showing a state where an ND filter is inserted by rotating a windmill member from the state of FIG. 1; FIG.
6 is a diagram showing an operation of the light amount adjusting device shown in FIG. 1. FIG.
FIG. 7 is a diagram illustrating a state in which an ND filter is retracted in an opened state of a light amount adjusting device according to a second embodiment of the present invention.
8 is a view showing a state in which the wind turbine member is rotated from the state of FIG.
9 is a view showing a state where a windmill member is rotated from the state shown in FIG. 8 to a mechanical end. FIG.
10 is a view showing a state where an ND filter is inserted by rotating a windmill member from the state of FIG. 7;
FIG. 11 is a diagram illustrating a state in which the ND filter is retracted in the opened state of the light amount adjusting device according to the third embodiment of the present invention.
12 is a view showing a state where the wind turbine member is rotated from the state shown in FIG. 11 and the diaphragm blades are narrowed down. FIG.
13 is a view showing a state where the windmill member is rotated from the state of FIG. 12 to the mechanical end. FIG.
14 is a view showing a state where an ND filter is inserted by rotating a windmill member from the state of FIG.
FIG. 15 is an exploded perspective view of the light amount adjusting device of the first embodiment.
FIG. 16 is a cross-sectional view of a digital still camera equipped with the light amount adjusting device of each of the embodiments.
[Explanation of symbols]
101 Ground plane
102 partition plate
103, 201, 301 Windmill member
103a, 201a, 301a Cam groove
103c, 201c Insertion protrusion
103d, 201d retracting protrusion
103e, 201e Arc projection
104 Aperture blade
107 holding plate
108, 202, 302 Filter holding frame
109 ND filter
110 Filter rotation axis
111 One-side spring
112 Alignment pin
113 Stepping motor
114 output pinion
115,203,303 Rotating pin
301c Filter cam

Claims (10)

A light amount adjusting device having an actuator and a light shielding member that is opened and closed by the actuator,
An optical filter that can be inserted into and retracted from the optical path independently of the light shielding member;
A filter holding member for holding the optical filter;
The optical filter is operated by at least one of the operation in the further opening direction of the actuator that has driven the light shielding member to the open position and the operation in the further fully closed direction of the actuator that has driven the light shielding member to the fully closed position. possess a driving mechanism for moving the,
The drive mechanism includes a rotating member that is rotated around the optical axis by the actuator,
The rotating member includes: a light shielding member driving unit that opens and closes the light shielding member; a filter driving unit that contacts the filter holding member to insert and retract the optical filter; and A light amount adjusting device comprising: a filter movement blocking unit that blocks movement of the optical filter in an insertion direction and a retracting direction by contact with a filter holding member .   2. The light quantity according to claim 1, wherein the drive mechanism inserts or retracts the optical filter with respect to the optical path by an operation in a further opening direction of the actuator that drives the light shielding member to an open position. Adjusting device.   2. The drive mechanism according to claim 1, wherein the optical filter retracts or inserts the optical filter with respect to the optical path by an operation in a further fully closed direction of the actuator that drives the light shielding member to a fully closed position. Light quantity adjustment device.   The drive mechanism starts the insertion or retraction movement of the optical filter with respect to the optical path by further operating the actuator that has driven the light shielding member to the open position by a predetermined amount in the open direction. 2. The light quantity adjusting device according to 2.   The drive mechanism is characterized in that the actuator that has driven the light shielding member to the fully closed position further moves a predetermined amount in the fully closed direction to start the retraction or insertion movement of the optical filter with respect to the optical path. The light quantity adjusting device according to claim 3.   6. The light amount adjusting device according to claim 4, wherein the driving mechanism is configured so that the light shielding member is not driven while the actuator operates in the predetermined amount of region.   Control means for controlling the driving speed of the actuator when moving the optical filter to be slower than the driving speed of the actuator when driving the light shielding member between the open position and the fully closed position. The light quantity adjusting device according to claim 1.   The light amount adjusting device according to claim 1, wherein the actuator is a stepping motor. An optical apparatus characterized by having an imaging optical system including a light amount adjustment device according to any one of claims 1 to 8. A photographing optical system including a light amount adjustment device according to any one of claims 1 to 8, the image pickup apparatus characterized by having an imaging means for imaging the subject image formed by the photographing optical system.

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