JP2015169744A - Light quantity adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a light quantity adjusting device by enabling optimal driving with a single driving source at times of moving image photographing and still image photographing.SOLUTION: A light quantity adjusting device includes: a first rotary member and a second rotary member in which an opening is formed and which rotate centering around a light axis; a single driving member capable of rotary driving the first or second rotary member; a light blocking member for changing an opening diameter of the opening by moving in tune with rotation of the first or second rotary member; a base member for supporting the driving member; a first restriction member for restricting the base member to movement in a direction orthogonal to the light axis of the first rotary member; and a second restriction member for restricting the first rotary member to movement in a direction orthogonal to the light axis of the second rotary member.

Description

  The present invention relates to a light amount adjusting device.

  In recent years, digital cameras that can shoot moving images as well as still images have been put on the market. Therefore, the aperture device mounted on the interchangeable lens of a digital camera is required to be driven at a high speed in order to improve the continuous shooting speed in still image shooting, and at the same time a very smooth low-speed drive is required in moving image shooting. The Smooth low-speed driving means that low-speed driving is performed with high resolution (in moving image shooting, when the aperture operation is low-resolution, an unnatural light amount change is acquired as a moving image and the quality is impaired). Further, at the time of still image shooting, it is desirable to be in a shooting standby state immediately after the power is turned on so as not to miss a photo opportunity.

  Conventionally, a diaphragm device has a diaphragm blade driven by a cam plate (cam plate) having one motor, one rotating ring (rotary plate) and one cam locus, and is driven at a high speed within the range of the characteristics of the motor. And low speed drive. Patent Document 1 discloses an electromagnetically driven aperture device that includes a stepping motor as a drive unit. Because it is an aperture device driven by a stepping motor, high-speed driving performance for continuous shooting in still image shooting is ensured by 1-2 phase driving, and smooth low-speed driving in movie shooting is achieved by microstep driving. It can be carried out.

JP-A-62-240942

  However, in Patent Document 1, high-speed and low-speed driving is performed with a single rotary plate directly connected to a motor. For this reason, the high-speed driving performance and the low-speed driving performance are uniquely determined from the driving characteristics of the motor alone, the reduction ratio by screwing the motor pinion and the rotary plate, and the setting of the cam locus of the cam plate. For example, if the surface magnetic flux density of the rotor magnet is increased to improve the driving force so as to satisfy the required high-speed driving performance, the smoothness of driving required for low-speed driving is impaired due to the increase of cogging torque. End up. Conversely, to satisfy the required low-speed drive performance, the rotor magnet's magnetizing pitch (the angle between the adjacent N pole and S pole) is reduced to increase the number of steps that can be stopped per rotation. Although it can drive smoothly, it cannot follow a high-speed drive command and cannot drive at high speed. As a countermeasure, a method of achieving driving accuracy and high speed using a motor with excellent stopping accuracy and large output torque can be considered. However, since a large motor is required, the entire apparatus becomes large.

  Further, a method of determining the aperture diameter based on the relative rotational position of both by rotating not only the rotary plate but also the cam plate is also conceivable. Specifically, in order to increase the speed of the diaphragm, the rotary plate and the cam plate may be rotated in opposite directions to increase the opening / closing speed of the diaphragm blades. On the other hand, when the aperture is slowed down, either the rotary plate or the cam plate is stopped, or the rotary plate and the cam plate are driven at different speeds in the same direction to decrease the aperture blade opening / closing speed. .

  However, in the above configuration, the fitting backlash with the first cover member that pivotally supports the rotation of the rotary plate, the fitting backlash with the second cover member that pivotally supports the rotation of the cam plate, and the first and first The attachment position shift of 2 cover members will arise. For this reason, the positional deviation in the direction perpendicular to the optical axis of the diaphragm blades increases, resulting in poor aperture accuracy. In addition, a drive source for driving the rotary plate and the cam plate separately and a separate base member for supporting the rotary plate and the cam plate are required, which increases the size of the apparatus.

  In view of such a problem, an object of the present invention is to downsize a light amount adjusting device by enabling optimal driving at the time of moving image shooting and still image shooting with a single drive source.

  A light amount adjusting device according to one aspect of the present invention includes a first rotating member and a second rotating member that are formed with an opening and that rotate about an optical axis, and the first or second rotating member is rotated. A single driving member that is possible, a light shielding member that changes the opening diameter of the opening by moving with the rotation of the first or second rotating member, and a base member that supports the driving member; A first restricting member that restricts movement of the first rotating member relative to the base member in a direction perpendicular to the optical axis, and an orthogonal to the optical axis of the second rotating member relative to the first rotating member. And a second restriction member that restricts movement in the direction in which the first rotation is performed, wherein the light quantity adjustment device performs the first rotation in a state where the drive member does not engage with the second rotation member. The first rotation by engaging a member A first state of rotating the material, a second state of rotating the second rotating member by engaging with the second rotating member in a state of not engaging with the first rotating member, By engaging with the first and second rotating members, a third state is achieved in which the first and second rotating members are engaged.

  According to another aspect of the present invention, there is provided a light amount adjusting device including a first rotating member and a second rotating member, each having an opening and rotating about an optical axis, and the first or second rotating member. A single drive member that can be driven to rotate, a light-shielding member that changes with the rotation of the first or second rotary member to change the opening diameter of the opening, and the first of the drive member Restriction for restricting rotation of the first rotating member accompanying rotation in the direction and rotation of the second rotating member accompanying rotation in the second direction opposite to the first direction of the driving member. And the light amount adjusting device rotates the first rotating member by engaging the first rotating member in a state where the driving member does not engage the second rotating member. The first rotation and the second rotation without engaging with the first rotating member A second state in which the second rotating member is rotated by engaging with the material, and the first and second rotating members are engaged by engaging with the first and second rotating members. It is characterized by being in the third state.

  According to the present invention, it is possible to downsize the light amount adjusting device by enabling optimal driving at the time of moving image shooting and still image shooting with a single drive source.

It is a block diagram of the camera system carrying the light quantity adjustment apparatus which concerns on embodiment of this invention. It is a disassembled perspective view of a light quantity adjustment apparatus. It is a perspective view of a rotary plate. It is a perspective view of a light quantity adjusting device. It is principal part sectional drawing of a light quantity adjustment apparatus. It is a conceptual diagram which shows the operation | movement order at the time of the still image photography of a light quantity adjustment apparatus. It is a conceptual diagram which shows the operation | movement order at the time of the video recording of a light quantity adjustment apparatus. It is a conceptual diagram which shows the operation | movement order of the adsorption | suction mechanism of a light quantity adjustment apparatus. It is a figure which shows the cam hole formed in the cam plate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  First, a camera system equipped with the light amount adjusting device of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of a camera system equipped with a light amount adjusting device of the present invention. This camera system includes a camera body 20 having an image sensor 22 and an interchangeable lens 10 attached to the camera body 20. The lens CPU 1 in the interchangeable lens 10 and the camera CPU 21 in the camera body 20 can communicate with each other via the lens communication contact 12 and the camera communication contact 27.

  In the interchangeable lens 10, the photographing optical system L is configured by the lens units L 1 to L 4 and the light amount adjusting device 100. The lens units L1 and L4 are fixed lens units, the lens unit L2 is a lens unit for zooming, and the lens unit L3 is a focus lens unit.

  The lens unit L2 is movable in the optical axis X direction by receiving an output from the zoom drive circuit 11 that has received a control signal from the lens CPU1. Thereby, the focal length of the photographing optical system L can be changed. The focal length detection circuit 9 detects the focal length of the photographing optical system L by detecting the position of the lens unit L2. The focal length detection circuit 9 detects the position of the lens unit L2 using a gray code pattern divided into 32 parts.

  The lens unit L3 is movable in the direction of the optical axis X by receiving the output of the focus driving circuit 3 that has received the control signal from the lens CPU1. Thereby, it is possible to adjust the focus of the photographing optical system L. A pulse generating unit is provided on the rotating member that is rotated by the drive of the focus driving motor. The pulse generation unit outputs a pulse signal corresponding to the rotation of the rotating member to the focus driving circuit 3. The lens CPU 1 detects the position of the lens unit L3 by detecting the pulse signal output from the pulse generation unit.

  The light quantity adjusting device 100 changes the aperture through which light passes by moving a plurality of diaphragm blades in a plane substantially orthogonal to the optical axis X. The diaphragm drive circuit 8 that has received the control signal from the lens CPU 1 drives the light amount adjusting device 100.

  The operation switch 2 performs zooming, focusing and aperture value setting by manual operation, switching between auto focus and manual focus, and the like.

  In the memory in the lens CPU 1, the ID of the interchangeable lens 10, focal length information, the amount of focus movement on the image sensor surface with respect to the amount of movement of the lens unit L 3 (hereinafter referred to as “focus sensitivity”), etc. Stored in

  The image of the subject 50 passes through the photographing optical system L in the interchangeable lens 10 and forms an image on the imaging surface (light receiving surface) of the imaging element 22 in the camera body 20. The imaging element 22 is configured by a photoelectric conversion element such as a CCD or a CMOS, and converts an optical image into an electrical signal by photoelectric conversion. The signal read from the image sensor 22 is subjected to amplification processing and A / D conversion processing, and then output to the camera CPU 21 as a digital video signal. In the camera system of this embodiment, a moving image or a still image is formed using a digital video signal.

  The digital video signal is output not only to the camera CPU 21 but also to an autofocus (hereinafter referred to as AF) processing circuit 29. When a digital video signal is input to the AF processing circuit 29, a high-frequency component in image data for one screen is extracted through a high-pass filter (HPF) or the like, and arithmetic processing such as cumulative addition is performed on the high-frequency component. Done. Thus, an AF evaluation value corresponding to the contour component amount on the high frequency side is calculated. Then, by moving the lens unit L3 to a position where the AF evaluation value shows a peak, focus detection by a so-called contrast detection method can be performed. The AF evaluation value calculated by the AF processing circuit 29 is output to the camera CPU 21. The focus adjustment operation in the camera system of the present embodiment is performed by moving the lens unit L3 in the optical axis direction based on the contrast detection method and the focus sensitivity information stored in the lens CPU1.

  The recording circuit 23 records the video signal on a recording medium that is detachable from the camera body 20. In the present embodiment, various buffer memories and the like are included in the camera CPU 21. The release switch 24 is composed of a two-stage switch of a switch (SW1) for starting photographing preparation operations such as photometry, focus detection and focusing operation, and a switch (SW2) for starting exposure to the image sensor 22. ing. The output signal of the release switch 24 is input to the camera CPU 21, and the camera CPU 21 performs an operation according to the input signal. On the display unit 25, for example, a moving image or a still image captured using the image sensor 22 is displayed.

  The camera CPU 21 performs various operations such as drive control of the display unit 25, control operation corresponding to an input from a setting switch 26 operated to perform a shooting mode, various settings, etc., checking of remaining capacity in the power supply 28, sharing of power, and the like. Control is in progress.

  Next, the light quantity adjusting device 100 of the present invention will be described with reference to FIGS. FIG. 2 is an exploded perspective view of the light amount adjusting device 100. FIG. 3 is a perspective view of the rotary plate. 1 is a cross-sectional view conceptually showing the configuration of a light amount adjusting device 100. FIG. FIG. 4 is a perspective view of the light amount adjusting device 100. FIG. 5 is a cross-sectional view of a main part of the light amount adjusting device 100.

  First, the component configuration of the light amount adjusting device 100 will be described.

  The light quantity adjusting device 100 includes a motor 101, a diaphragm blade 102, a rotary plate 103, a cam plate 104, a base plate 105, and an electromagnet 106. The rotary plate 103, the cam plate 104, and the base plate 105 are each formed with a hole centered on the optical axis, and serve as an opening through which subject light passes.

  A motor (driving member) 101 is supported by a base plate 105, and a pinion 101-1 is attached to a rotating shaft.

  The aperture blade (light-shielding member) 102 is composed of blade members 102a to 102f. Fitting shaft portions 102a-1 to 102f-1 and fitting shaft portions 102a-2 to 102f-2 are formed on both surfaces of the blade members 102a to 102f, respectively.

  The rotary plate (first rotating member) 103 includes a gear portion 103-1, engagement piece portions 103-2a to 103-2c, and protruding piece portions 103-3a to 103-3c. Moreover, the hole parts 103-4 and 103-5a-103-5f are formed, and it has the projection part 103-6a-103-6c and the fitting axial part 103-7. Moreover, it has the protrusion piece part 103-8 formed in the outer periphery part, and the adsorption | suction piece part 103-9 provided integrally with it and formed with the magnetic material. Further, grooves 103-10a to 103-10c (103-10c are shown in FIG. 3) are formed, and suction protrusions 103-11 (shown in FIG. 4) that adsorb to the suction protrusions 104-6 of the cam plate 104 are formed. Have.

  The cam plate (second rotating member) 104 includes a gear portion 104-1, cam hole portions 104-2a to 104-2f, and protruding piece portions 104-3a to 104-3c (104-3a) protruding in the optical axis direction. Only projecting long). Further, the suction piece 104-4, the protrusions 104-5a to 104-5c, which are integrally provided on the side surface of the protruding piece 104-3a and formed of a magnetic material, and the suction protrusion 103- of the rotary plate 103 are provided. 11 is formed on the suction projection 104-6. Engagement sections 104-3a-1 to 104-3c-1 projecting in the center direction of the optical axis are formed on the projecting piece sections 104a-3a to 104-3c.

  The base plate (base member) 105 is formed with a hole 105-1, a fitting hole 105-2 that fits with the rotary plate 103, and insertion grooves 105a to 105c when the rotary plate 103 is assembled. Moreover, it has a fixing part (not shown) for fixing the motor 101 and the electromagnet 106.

  The electromagnet 106 includes a coil 106a and a soft magnetic member 106b such as an electromagnetic steel plate. The soft magnetic member 106b is formed with face portions 106b-1 and 106b-2 on which the attracting piece portions 103-9 and 104-4 are attracted, respectively. The electromagnet 106 functions as a regulating member of the present invention together with the attracting piece portions 103-9 and 104-4. A control circuit (control unit) (not shown) can control the energization of the coil 106a.

  Although not shown, the diaphragm driving circuit 8, the motor 101, and the coil 106a are connected to each other so as to transmit signals.

  Next, assembly of components of the light amount adjusting device 100 will be described.

  The motor 101 and the electromagnet 106 are fixed to the base plate 105 with a fastening member such as a screw. The aperture blade 102 is disposed between the rotary plate 103 and the cam plate 104.

  When attaching the cam plate 104 to the rotary plate 103, first, the protruding pieces 104-3 a to 104-3 c of the cam plate 104 are inserted into the grooves 103-10 a to 103-10 c of the rotary plate 103. Then, the cam plate 104 is rotated around the optical axis with respect to the rotary plate 103, and the engaging portions 104-3a-1 to 104-3c-1 are engaged with the engaging piece portions 103-2a to 103-2c. By doing so, the rotary plate 103 and the cam plate 104 do not come off in the optical axis direction (bayonet structure). Moreover, the movement to the direction orthogonal to an optical axis is restrict | limited by the fitting of the outer peripheral surface part of engagement piece part 103-2a-103-2c and the inner peripheral surface part of protrusion piece part 104-3a-104-3c. . Moreover, the space | interval of the aperture blade 102 is ensured because the projection part 104-5a-104-5c contact | abuts on the surface of the rotary plate 103. FIG. The fitting shaft portions 102 a-1 to 102 f-1 of the diaphragm blade 102 are fitted in the holes 103-5 a to 103-5 f of the rotary plate 103, and the fitting shaft portions 102 a-2 to 102 f-2 are fitted to the cam plate 104. The cam holes 104-2a to 104-2f are fitted. Through the above assembly, the aperture blade 102, the rotary plate 103, and the cam plate 104 are unitized as an aperture blade unit.

  When attaching the diaphragm blade unit to the base plate 105, first, the protruding pieces 103-3 a to 103-3 c of the rotary plate 103 are inserted into the grooves 105 a to 105 c of the base plate 105. Then, the diaphragm blade unit is rotated around the optical axis with respect to the base plate 105 so that the base plate 105 and the diaphragm blade unit do not come off in the optical axis direction (bayonet structure). Further, the fitting shaft portion 103-7 is fitted into the fitting hole portion 105-2, thereby restricting the movement of the aperture blade unit in the direction orthogonal to the optical axis. Further, the protrusions 103-6a to 103-6c abut against the surface of the base plate 105, so that the position of the diaphragm blade unit in the optical axis direction with respect to the base plate 105 is maintained at a constant distance. The protruding piece portion 103-8, the suction piece portion 103-9, the protruding piece portion 104-3a, and the suction piece portion 104-4 are inserted into the hole portion 105-1 of the base plate 105, and the pinion 101-1 and the gear portion 103- are inserted. 1,104-1 is meshing.

  By assembling as described above, the light amount adjusting device 100 shown in FIG. 4 is obtained. In the present embodiment, the outer peripheral surface portions of the engaging piece portions 103-2a to 103-2c and the protruding piece portions 104-3a to 104-3c restrict the movement of the rotary plate 103 in the direction perpendicular to the optical axis with respect to the cam plate 104. Functions as a limiting member. Further, the fitting shaft portion 103-7 and the fitting hole portion 105-2 function as a limiting member that restricts movement of the rotary plate 103 in the direction perpendicular to the optical axis with respect to the base plate 105. Therefore, the displacement in the direction perpendicular to the optical axis of the aperture blade 102 that greatly affects the aperture aperture accuracy is mainly only the engagement backlash between the rotary plate 103 and the cam plate 104 and the backlash between the rotary plate 103 and the base plate 105. It becomes. That is, the aperture accuracy is improved by at least the positional deviation caused by the attachment of another member (corresponding to 201 in FIG. 5) and the base plate 105, which are conventionally provided for pivotally supporting the cam plate 104.

  In this embodiment, an engaging portion with the base plate 105 is provided on the rotary plate 103 side close to the base plate 105. Thereby, the rotation fitting part (part where the fitting shaft part 103-7 and the fitting hole part 105-2 are fitted) and the optical axis direction restricting part (the protruding piece part 103-3a and the base plate) of the diaphragm blade unit. The portion with which 105 abuts can be disposed in the vicinity of the opening diameter of the diaphragm. Therefore, the friction load on the motor 101 can be reduced. If the engaging portion with the base plate 105 is provided on the cam plate 104 side away from the base plate 105, the engaging portion cannot be arranged with a diameter smaller than the opening of the aperture blade 102. Therefore, the engaging portion is inevitably arranged with a diameter larger than the outer periphery of the diaphragm blade. As a result, the frictional load generated in the aperture blade unit is increased and the motor 101 is burdened, which increases the power consumption. Therefore, it is desirable to provide the engaging portion of the aperture blade unit on the rotating member side close to the base plate 105.

  In the present embodiment, as shown in FIG. 5, the cam plate 104 is pivotally supported by the rotary plate 103 (unitized including the diaphragm blades 102). Therefore, the protruding piece 104a of the cam plate 104 that has been necessary in the past (part having the same function as the protruding piece 103-3a) and another member that fits and supports the protruding piece 104a (indicated by dotted lines). The other base plate 201) shown is not necessary. As a result, it is possible to reduce the size of the device as compared with the conventional case.

  With the above configuration, when the motor 101 is energized, the rotary plate 103 and the cam plate 104 can rotate around the optical axis. The aperture blade 102 is driven by the relative rotation angle between the rotary plate 103 and the cam plate 104, and the aperture diameter can be changed. As will be described later, when the electromagnet 106 is energized, the soft magnetic member 106b attracts and selectively fixes one of the attracting piece portions 103-9 and 104-4. As will be described in detail below, depending on the rotational position of the rotary plate 103 and the cam plate 104, the pinion 101-1 is configured to be disengaged. It is designed not to rotate.

  Next, the driving sequence of the light amount adjusting device of the present invention will be described in detail with reference to FIGS. FIG. 6 is a conceptual diagram showing an operation sequence during still image shooting, and FIG. 7 is a conceptual diagram showing an operation sequence during moving image shooting. 6 and 7 schematically show the positional relationship between the rotary plate 103, the cam plate 104, and the pinion 101-1. 6 and 7, the dotted line P indicates the position of the pinion 101-1. Further, the gear portion 103-1 of the rotary plate 103 and the gear portion 104-1 of the cam plate 104 are hatched portions in FIGS. The stopper portions 105d and 105e restrict the rotation of the rotary plate 103 and the cam plate 104, respectively.

  First, the driving of the rotary plate 103 and the cam plate 104 during still image shooting will be described with reference to FIG.

  FIG. 6A shows an initial state when the power is turned off. Since the rotary plate 103 is in contact with the surface portion 106b-1, movement in the left direction in the figure is restricted. The gear part 103-1 is not engaged with the pinion 101-1, and only the gear part 104-1 is engaged with the pinion 101-1. Further, the suction protrusion 103-11 and the suction protrusion 104-6 are sucked.

  FIG. 6B shows a shooting standby state. The rotary plate 103 is in contact with the surface portion 106b-1, and the suction piece portion 103-9 is sucked and stopped by energization of the coil 106a. On the other hand, since the cam plate 104 is rotated leftward in the drawing by the motor 101, the suction projection 104-6 is separated from the suction projection 103-11. In this state, the aperture blade 107 is open.

  FIG. 6C shows a state where the cam plate 104 is further moved leftward in the drawing from the state of FIG. At this time, the cam plate 104 is not in contact with the stopper portion 105e, and the aperture blade 102 is in a small aperture state. That is, in the still image shooting, the light amount adjustment operation is performed between the states shown in FIGS.

  When the photographing is finished and the power is turned off, the cam plate 104 moves to the right in the figure and enters the state shown in FIG. FIG. 6 (d) shows the same state as FIG. 6 (a).

  In addition, since the relationship between the magnetic attractive force and the separation distance is not linear, there is a concern about the influence of the light quantity change due to the vibration of each rotary plate at the time of attracting the attracting protrusions 104-6 and 103-11 or immediately after being released from the attracting. The In the present embodiment, since the aperture blade 102 is in an open state in FIGS. 6A, 6B, and 6D, the above-mentioned concern does not become a problem.

  Further, since the rotary plate 103 can be operated from shooting standby to opening and closing of the aperture blade 102 without being driven at all, the aperture driving can be started immediately after the power is turned on, and imaging can be performed immediately. This is important in order not to miss a photo opportunity when taking a still image.

  Next, driving of the rotary plate 103 and the cam plate 104 during moving image shooting will be described with reference to FIG. During moving image shooting, the motor 101 is driven in the opposite direction to that during still image shooting.

  FIG. 7A shows an initial state when the power is turned off. Since the rotary plate 103 is in contact with the surface portion 106b-1, movement in the left direction in the figure is restricted. The gear part 103-1 is not engaged with the pinion 101-1, and only the gear part 104-1 is engaged with the pinion 101-1. Further, the suction protrusion 103-3 and the suction protrusion 104-6 are sucked.

  FIG. 7B shows a state immediately after the power is turned on. When the cam plate 104 is driven in the right direction in the figure from the state of FIG. 7A, the cam plate 104 integrally moves in the right direction in the figure while adsorbing to the rotary plate 103. Thereafter, as shown in FIG. 7B, the gear portion 103-1 meshes with the pinion 101-1. That is, the gear parts 103-1 and 104-1 are both meshed with the pinion 101-1.

  FIG. 7C shows a state where the rotary plate 103 and the cam plate 104 are further moved rightward in the drawing from the state of FIG. At this time, the gear part 104-1 is not meshed with the pinion 101-1, and only the gear part 103-1 is meshed with the pinion 101-1.

  FIG. 7D shows a state where the rotary plate 103 and the cam plate 104 are further moved rightward in the drawing from the state of FIG. In the state of FIG. 7 (c), the gear portion 104-1 and the pinion 101-1 are disengaged, but since the suction projection portion 103-11 and the suction projection portion 104-6 are attracted, the rotary plate 103 The cam plate 104 moves with driving. Then, the cam plate 104 abuts on the surface portion 106b-2, and movement in the right direction in the figure is restricted.

  FIG. 7E shows a shooting standby state. The cam plate 104 is stopped because it is in contact with the surface portion 106b-2, but the rotary plate 103 can be driven to rotate rightward in the figure by the motor 101. At this time, the suction protrusion 103-11 is separated from the suction protrusion 104-6. In this state, the aperture blade 102 is in an open state.

  FIG. 7F shows a state where the rotary plate 103 is further moved to the right in the drawing from the state of FIG. At this time, the rotary plate 103 is not in contact with the stopper portion 105d, and the aperture blade 102 is in a small aperture state. That is, in moving image shooting, the light amount adjustment operation is performed between FIGS.

  When the photographing is finished and the power is turned off, the energization to the coil 106a is cut off, and the rotary plate 103 moves to the left in the figure to be in the state of FIG. 7 (g). FIG. 7 (g) shows the same state as FIG. 7 (a).

  In addition, since the relationship between the magnetic attractive force and the separation distance is not linear, there is a concern about the influence of the light quantity change due to the vibration of each rotary plate at the time of attracting the attracting protrusions 103-11 and 104-6 or immediately after being released from the attracting. The In this embodiment, since the aperture blade 102 is in the open state in FIGS. 7A to 7E and 7G, the above-mentioned concern does not become a problem.

  Of the above operation sequence, the principle of attraction between the electromagnet 106 and the attraction pieces 103-9 and 104-4 will be described in more detail with reference to FIG. FIG. 8 is a schematic diagram showing how the electromagnet 106 and the suction piece portions 103-9 and 104-4 are attracted.

  FIG. 8A shows a state in which the attracting piece portion 103-9 is attracted to the surface portion 106b-1 of the soft magnetic member 106b of the electromagnet 106. The attracting piece 103-9 is composed of a permanent magnet, and as shown in FIG. 8A, the contact surface with the face 106b-1 is an S pole. In this state, the coil 106a is not energized and is attracted by the magnetic attraction force of the attracting piece 103-9. This state corresponds to the states of FIGS. 6A to 6C and FIG.

  FIG. 8B shows a state where the suction piece 103-9 is separated from the face 106b-1 by energization of the coil 106a. Since the vicinity of the surface portion 106b-1 is excited to the S pole by energization of the coil 106a, the surface of the attracting piece portion 103-9 is repelled by the same polarity as the contact surface (S pole) with the surface portion 106b-1. Power is generated. Therefore, the suction piece 103-9 is separated from the face 106b-1. This state is a state immediately after the rotary plate 103 is released from the suction state when the state shown in FIG. 6A is shifted to the state shown in FIG. Note that the energization of the coil 106a is interrupted after the rotary plate 103 is separated for power saving.

  FIG. 8C shows a state where the attracting piece portion 104-4 is attracted to the surface portion 106 b-2 of the soft magnetic member 106 b of the electromagnet 106. The attracting piece 104-4 is composed of a permanent magnet, and as shown in FIG. 8C, the contact surface with the face 106b-2 is an S pole. In this state, the coil 106a is not energized and is attracted by the magnetic attractive force of the attracting piece 104-4. This state corresponds to the state shown in FIGS.

  FIG. 8D shows a state where the suction piece 104-4 is separated from the face 106b-2 by energization of the coil 106a. Since the vicinity of the surface portion 106b-2 is excited to the south pole by energization of the coil 106a, the surface of the attracting piece 104-4 is in contact with the surface portion 106b-2 (the south pole) and has the same polarity as each other. Power is generated. Therefore, the suction piece 104-4 is separated from the surface 106b-2. This state is a state immediately after the cam plate 104 is released from the suction state when the state shown in FIG. 7F is shifted to the state shown in FIG. Note that the energization of the coil 106a is interrupted after the cam plate 104 is separated for power saving.

  According to the above attracting method, it is not necessary to attract the rotary plate 103 and the cam plate 104 by separate electromagnets, and since it is performed by one electromagnet, the number of parts can be reduced and the apparatus can be miniaturized. The poles of the electromagnet 106 that are excited and the poles of the attracting pieces 103-9 and 104-4 may be in a relationship of N poles. In addition, it has been described that the energization of the coil 106a is cut off for power saving. However, the coil 106a may be in an energized state in order to securely hold the device even if vibration or impact is applied to the apparatus. The attracting piece portions 103-9 and 104-4 may be metal pieces such as electromagnetic steel plates. In this case, the coil 106a may be energized and excited at all times when attracted.

  By the way, when one of the cam holes 104-2a to 104-2f formed in the cam plate 104 is enlarged, a shape as shown in FIG. 9 is obtained. As for the cam part 104-2-a, when the rotary plate 103 rotates during moving image shooting, the fitting shaft parts 102a-2 to 102f-2 of the blade members 102a to 102f slide. On the other hand, in the cam portion 104-2-b, the fitting shaft portions 102a-2 to 102f-2 slide when the cam plate 104 rotates during still image shooting. Compared with the cam portion 104-2-a, the cam portion 104-2-b has a larger cam track inclination angle with respect to the rotation direction of the cam plate 104 (R direction in the figure) (α> β in the figure). Is related). Accordingly, the diaphragm blade 107 can be driven at a high speed during still image shooting, and can be driven at a lower speed than during still image shooting during moving image shooting. That is, the opening / closing operation speed of the opening can be increased at the time of still image shooting compared to the time of moving image shooting. This is necessary at the time of still image shooting that requires high speed shooting such as continuous shooting. The cam portion 104-2-c has a cam locus that is substantially in the same direction as the rotation direction of the cam plate 104 (R direction in the figure). 6 (a), (b), (d) and FIGS. 7 (a) to (e), (g), the fitting shaft portions 102a-2 to 102f-2 are connected to the cam portions 104-2-c. The aperture blade 102 is kept open by sliding.

  According to the above configuration, the apparatus can be miniaturized by enabling optimum driving during moving image shooting and still image shooting with a single drive source.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

101 Motor (drive member)
102 Aperture blade (shading member)
103 Rotary plate (first rotating member)
103-2a to 103-2c engaging piece (second limiting member)
103-7 Fitting shaft (first limiting member)
104 Cam plate (second rotating member)
104-3a to 104-3c projecting piece (second limiting member)
105 Base plate (base member)
105-2 Fitting hole (first limiting member)

Claims (5)

A first rotating member and a second rotating member each having an opening formed therein and rotating about the optical axis;
A single driving member capable of rotationally driving the first or second rotating member;
A light shielding member that changes the opening diameter of the opening by moving with the rotation of the first or second rotating member;
A base member that supports the drive member;
A first restricting member for restricting movement of the first rotating member relative to the base member in a direction perpendicular to the optical axis;
A second light limiting device that restricts movement of the second rotating member in a direction perpendicular to the optical axis with respect to the first rotating member,
The light quantity adjusting device includes a first state in which the first rotating member is rotated by engaging the first rotating member in a state where the driving member is not engaged with the second rotating member, A second state in which the second rotating member is rotated by engaging with the second rotating member without being engaged with the first rotating member, and an engagement with the first and second rotating members. By doing so, the light quantity adjusting device is in a third state in which the first and second rotating members are engaged.   2. The light amount adjusting device according to claim 1, wherein the first rotating member is disposed closer to the base member than the second rotating member in the optical axis direction. A first rotating member and a second rotating member each having an opening formed therein and rotating about the optical axis;
A single driving member capable of rotationally driving the first or second rotating member;
A light shielding member that changes the opening diameter of the opening by moving with the rotation of the first or second rotating member;
The rotation of the first rotating member accompanying the rotation of the driving member in the first direction, and the second rotation accompanying the rotation of the driving member in the second direction opposite to the first direction. A regulating member that regulates rotation of the member,
The light quantity adjusting device includes a first state in which the first rotating member is rotated by engaging the first rotating member in a state where the driving member is not engaged with the second rotating member, A second state in which the second rotating member is rotated by engaging with the second rotating member without being engaged with the first rotating member, and an engagement with the first and second rotating members. By doing so, the light quantity adjusting device is in a third state in which the first and second rotating members are engaged. The regulating member has a first suction part formed on the first rotating member, a second suction part formed on the second rotating member, and a third suction part,
The rotation of the first rotating member accompanying the rotation of the driving member in the first direction is regulated by the adsorption of the first adsorption part and the third adsorption part,
The rotation of the second rotating member accompanying the rotation of the driving member in the second direction is regulated by the adsorption of the second adsorption part and the third adsorption part. Item 4. The light amount adjusting device according to Item 3. The first and second attracting portions are magnetic members,
The light amount adjusting device according to claim 4, wherein the third attracting unit includes an electromagnet and a control unit capable of controlling energization of the electromagnet.