Patent Publication Number: US-9904145-B2

Title: Blade drive device and optical instrument

Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2016-128789 filed on Jun. 29, 2016, the entire content of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a blade drive device and an optical instrument. 
     Background Art 
     An optical instrument such as a digital camera is equipped with a focal plane shutter (hereinafter, referred to as an FP shutter) in order to control exposure to an imaging element. The FP shutter has a substrate which has an opening (picture frame), and a front curtain and a rear curtain which are movable along an opening surface of the opening so as to open and close the opening. 
     For example, JP-A-2014-170022 discloses a so-called electromagnetic drive-type FP shutter which actuates the front curtain and the rear curtain by using an electromagnetic actuator. Compared with a so-called spring drive-type FP shutter (system for actuating the front curtain and the rear curtain by using an attraction force generated by an electromagnet and a restoring force of a spring), the electromagnetic drive-type FP shutter has an advantage in that the FP shutter is miniaturized and simplified. 
     SUMMARY OF THE INVENTION 
     Incidentally, according to the FP shutter used for a mirrorless single lens camera or a digital single lens reflex camera, the front curtain and the rear curtain need to be located at each open position (state where the opening is fully opened) when the power is not supplied such as when the power is turned off. In this case, the above-described electromagnetic drive-type FP shutter holds the open position of the front curtain and the rear curtain by using a detent torque (magnetic attraction force in a state where power is not supplied) of the electromagnetic actuator. 
     However, according to the electromagnetic drive-type FP shutter in the related art, there is a possibility that the front curtain or the rear curtain may be unexpectedly moved in a closing direction due to a drop impact. Consequently, there is still room for improvement in that impact resistance has to be ensured while less power consumption and miniaturization have to be achieved. 
     Therefore, the invention is made in view of the above-described circumstances, and an object thereof is to provide a blade drive device and an optical instrument which can ensure the impact resistance while the less power consumption and the miniaturization can be achieved. 
     In order to solve the above-described problem, a blade drive device according to an aspect of the invention includes a substrate that has an opening, a first curtain and a second curtain that are movable along an opening surface of the opening so as to open and close the opening, a first locking portion that interlocks with opening and closing operations of at least the first curtain, a blade position holding member that is configured to be pivotally movable around a first axis extending in a first direction intersecting the opening surface, that enters an operation trajectory of the first locking portion in response to the opening and closing operations of the first curtain, and that is capable of entry and escape between an entry position for regulating the movement of the first curtain in a closing direction and an escape position escaped from the operation trajectory, an electromagnetic actuator that extends in the first direction, and that is configured to be rotatable around a second axis which is different from the first axis, and a linkage lever that connects the blade position holding member and the electromagnetic actuator to each other, and that causes the blade position holding member to pivot around the first axis in response to the rotation around the second axis of the electromagnetic actuator. The blade position holding member and the linkage lever engage with each other while being provided with play in a pivoting direction around the second axis of the linkage lever. 
     According to this configuration, the blade position holding member and the linkage lever engage with each other while being provided with play in the pivoting direction around the second axis of the linkage lever. Accordingly, when the linkage lever pivots, until the linkage lever and the blade position holding member engage with each other, the linkage lever runs idle with respect to the blade position holding member. Therefore, it is possible to reduce a load torque applied to the electromagnetic actuator. In this manner, miniaturization of the electromagnetic actuator can be achieved, and less power consumption of the blade drive device can be achieved. Since the blade position holding member and the linkage lever engage with each other while being provided with play in the pivoting direction around the second axis of the linkage lever, compared with a case where the blade position holding member is interlocked with a rotation operation of the electromagnetic actuator, it is possible to minimize a pivoting range of the blade position holding member with respect to an actuation angle of the electromagnetic actuator. In this manner, the electromagnetic actuator can be more freely selected, and the blade position holding member is likely to be set in a desired pivoting range with respect to the actuation angle of the electromagnetic actuator. In this regard, the blade drive device can be more freely designed. 
     In the aspect, the blade position holding member can be locked by the first locking portion at the entry position so as to regulate the movement of the first curtain in the closing direction. Accordingly, it is possible to restrain the first curtain from being unexpectedly moved in the closing direction due to a drop impact. In this manner, it is not necessary to increase a detent torque of the electromagnetic actuator in order to hold the first curtain at the open position. Therefore, a miniaturized device, a quickened shutter operation, and impact resistance can be realized. 
     In the aspect, the linkage lever may include a linkage pin which is loosely inserted into a guide hole of the blade position holding member. An inner peripheral surface of the guide hole may have a first engagement portion with which the linkage pin engages in response to one side pivoting movement around the second axis of the linkage lever, and a second engagement portion with which the linkage pin engages in response to the other side pivoting movement around the second axis of the linkage lever. Inside the guide hole in the pivoting direction of the linkage lever around the second axis, clearances between the linkage pin and the first engagement portion and between the linkage pin and the second engagement portion may configure idle running regions in which the linkage pin runs idle with respect to the blade position holding member in response to the pivoting movement around the second axis of the linkage lever. 
     According to this configuration, when the linkage lever pivots to one side around the second axis in a state where the linkage lever engages with the first engagement portion, the linkage lever engages with the second engagement portion after passing through the idle running region. Accordingly, the linkage lever and the blade position holding member pivot integrally with each other. When the linkage lever pivots to the other side around the second axis in a state where the linkage lever engages with the second engagement portion, the linkage lever engages with the first engagement portion after passing through the idle running region. Accordingly, the linkage lever and the blade position holding member pivot integrally with each other. In this manner, the above-described operation effect is more successfully achieved. 
     In the aspect, the inner peripheral surface of the guide hole may have an escape portion which escapes from contact with the linkage lever in a radial direction of the second axis. 
     According to this configuration, the inner peripheral surface of the guide hole has the escape portion which escapes from the contact with the linkage lever in the radial direction of the second axis. Accordingly, it is possible to reliably reduce a load torque applied to the electromagnetic actuator. 
     In the aspect, the blade drive device may further include a biasing member that biases the blade position holding member toward the escape position. 
     According to this configuration, it is possible to restrain rattling of the blade position holding member. Therefore, it is possible to restrain a shutter operation from being hindered by the blade position holding member after the blade position holding member unexpectedly enters the entry position. 
     In the aspect, at the entry position, the blade position holding member may be locked by the first locking portion in an open region in which the first curtain escapes from the opening when viewed in the first direction. 
     According to this configuration, it is possible to reliably restrain the first curtain from entering the inside of the opening. Therefore, for example, it is possible to reliably restrain the first curtain from appearing on a monitor of the optical instrument. 
     In the aspect, the first curtain and the second curtain respectively may have a plurality of blades. In an overlapped state where the plurality of blades are overlapped with each other when viewed in an opening direction of the opening, the plurality of blades escape from the opening so as to bring the first curtain and the second curtain to an open position. In an expanded state where the plurality of blades are expanded when viewed in the opening direction, the plurality of blades close the opening so as to bring the first curtain and the second curtain to a closed position. 
     According to this configuration, the plurality of blades are held at the open position in the overlapped state. Therefore, for example, compared with a case where a single blade opens and closes the opening, the respective blades can be miniaturized. 
     In the aspect, the blade drive device may further include a second locking portion that interlocks with the opening and closing operations of the second curtain. At the entry position, the blade position holding member may enter both an operation trajectory of the first locking portion operated in response to the opening and closing operations of the first curtain and an operation trajectory of the second locking portion operated in response to the opening and closing operations of the second curtain so as to regulate the movement of the first curtain and the second curtain in the closing direction. 
     According to this configuration, the blade position holding member can be locked by both the first curtain locking portion and the second curtain locking portion at the entry position. Accordingly, it is possible to restrain the first curtain and the second curtain from being unexpectedly moved in the closing direction due to a drop impact. In this manner, it is not necessary to increase a detent torque of the electromagnetic actuator in order to hold the first curtain and the second curtain at the open position. Therefore, a miniaturized device, a quickened shutter operation, and impact resistance can be realized. 
     Moreover, the movement of the first curtain and the second curtain in the closing direction can be regulated by the single blade position holding member. Therefore, compared with a case where the blade position holding member is disposed in each of the first curtain and the second curtain, the blade drive device can be miniaturized. 
     An optical instrument according to another aspect of the invention includes the blade drive device according to the aspect described above. 
     According to this configuration, the optical instrument includes the blade drive device according to the aspect described above. Therefore, it is possible to provide the optical instrument which is miniaturized and requires less power consumption while impact resistance is ensured. 
     According to the aspect of the invention, it is possible to provide the blade drive device and the optical instrument which are miniaturized and require less power consumption while impact resistance is ensured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an optical instrument according to an embodiment of the invention. 
         FIG. 2  is a plan view illustrating a state where a blade position holding mechanism is located at an entry position in an FP shutter according to the embodiment. 
         FIG. 3  is a plan view illustrating a state where a front curtain is located at a closed position in the FP shutter according to the embodiment. 
         FIG. 4  is a plan view illustrating a state where a rear curtain is located at the closed position in the FP shutter according to the embodiment. 
         FIG. 5  is an enlarged plan view illustrating a state where the blade position holding mechanism is located at the entry position in the FP shutter according to the embodiment. 
         FIG. 6  is an enlarged plan view illustrating a state where the blade position holding mechanism is located at an escape position in the FP shutter according to the embodiment. 
         FIG. 7  is a plan view illustrating a state where the blade position holding mechanism is located at the escape position in the FP shutter according to the embodiment. 
         FIG. 8  is a plan view illustrating an exposure operation in the FP shutter according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Next, an embodiment according to the invention will be described with reference to the drawings. 
     Optical Instrument 
       FIG. 1  is a block diagram of an optical instrument  1 . 
     As illustrated in  FIG. 1 , for example, the optical instrument  1  is used as a mirrorless single lens camera or a digital single lens reflex camera. The optical instrument  1  includes an FP shutter (blade drive device)  2 , a control unit  3 , and an imaging element  4 . 
     The control unit  3  controls an overall operation of the optical instrument  1 . For example, the control unit  3  includes a CPU, a ROM, and a RAM. 
     For example, the imaging element  4  is a CCD or a CMOS image sensor. The imaging element  4  converts an object image formed by light into an electric signal. 
     The optical instrument  1  includes a lens (not illustrated) for adjusting a focal length. 
     FP Shutter 
       FIG. 2  is a plan view illustrating a state where a blade position holding mechanism  13  is located at an entry position in the FP shutter  2 . 
     As illustrated in  FIG. 2 , the FP shutter  2  mainly has a substrate  10 , a front curtain mechanism  11 , a rear curtain mechanism  12 , and the blade position holding mechanism  13 . 
     The substrate  10  has an opening  15  into which the substrate  10  penetrates in a direction of an optical axis P. In the substrate  10 , a sector region is defined between the substrate  10  and a blade receiving plate (not illustrated) disposed on one side in the direction of the optical axis P from the substrate  10 . The blade receiving plate has an opening (not illustrated) having the same shape as the opening  15  in a plan view when viewed in the direction of the optical axis P. In the substrate  10 , a drive region is defined between the substrate  10  and a drive receiving plate  16  disposed on the other side in the direction of the optical axis P from the substrate  10 . In the drawing, members disposed in the sector region are indicated by a two-dot chain line, and members disposed in the drive region are indicated by a solid line or a broken line. 
     Front Curtain Mechanism 
     The front curtain mechanism  11  opens and closes the opening  15  by causing a so-called parallel link to convert pivoting movement around a front curtain axis O 1  extending along the direction of the optical axis P into slide movement in a direction orthogonal to the optical axis P (X-direction illustrated in  FIG. 2 ). Specifically, the front curtain mechanism  11  has a front curtain electromagnetic actuator  21 , a front curtain drive lever  22 , front curtain arms (first front curtain arm  23  and second front curtain arm  24 ), and a front curtain  25 . In the front curtain mechanism  11 , the front curtain electromagnetic actuator  21  and the front curtain drive lever  22  are disposed in the above-described drive region. On the other hand, the front curtain arms  23  and  24  and the front curtain  25  are disposed in the above-described sector region. 
     The front curtain electromagnetic actuator  21  has a front curtain stator  31  and a front curtain rotor  32 . 
     The front curtain stator  31  is formed in a U-shape in a plan view. The front curtain stator  31  is equipped with a front curtain coil  33  for exciting the front curtain stator  31 . 
     The front curtain rotor  32  is accommodated inside the front curtain stator  31 . The front curtain rotor  32  is configured to be rotatable around the front curtain axis O 1  extending along the direction of the optical axis P. A rotary shaft  32   a  of the front curtain rotor  32  faces the sector region after penetrating the substrate  10 . 
     The front curtain drive lever  22  pivots around the front curtain axis O 1  in response to the rotation of the front curtain rotor  32 . Specifically, the front curtain drive lever  22  extends in a direction orthogonal to the direction of the optical axis P. A base end portion of the front curtain drive lever  22  is coupled to the rotary shaft  32   a  of the front curtain rotor  32 . A front curtain coupling pin  35  extending to one side in the direction of the optical axis P is disposed to protrude in a tip portion of the front curtain drive lever  22 . The front curtain coupling pin  35  faces the sector region through a guide groove  37  formed in the substrate  10 . The guide groove  37  is formed in an arc shape extending along a circumferential direction around the front curtain axis O 1 . That is, in response to the pivoting movement of the front curtain drive lever  22 , the front curtain coupling pin  35  moves inside the guide groove  37 . In this manner, a pivoting range of the front curtain drive lever  22  is regulated. 
     The first front curtain arm  23  extends in the direction orthogonal to the direction of the optical axis P. The base end portion of the first front curtain arm  23  is coupled to the front curtain coupling pin  35  and the rotary shaft  32   a  of the front curtain rotor  32  so as to be pivotally movable. That is, the first front curtain arm  23  is configured to be rotatable around the front curtain axis O 1  in response to the rotation of the front curtain rotor  32 . 
     The second front curtain arm  24  extends to follow the first front curtain arm  23  in the direction orthogonal to the direction of the optical axis P. The base end portion of the second front curtain arm  24  is supported so as to be pivotally movable around a support pin  39  protruding to one side in the direction of the optical axis P from the substrate  10 . 
     The front curtain  25  has a plurality of (for example, four) blades  25   a  to  25   d . The respective blades  25   a  to  25   d  extend in a direction (Y-direction in  FIG. 2 ) orthogonal to an X-direction in a plan view. Each of the base end portions of the blades  25   a  to  25   d  is coupled to both the first front curtain arm  23  and the second front curtain arm  24  so as to be pivotally movable. In response to the drive of the front curtain electromagnetic actuator  21 , the blades  25   a  to  25   d  are switched between an overlapped state where the blades  25   a  to  25   d  are overlapped with each other in a plan view and an expanded state (refer to  FIG. 3 ) where the blades  25   a  to  25   d  are expanded in a plan view. In the overlapped state, the blades  25   a  to  25   d  escape from the opening  15  to one side in the X-direction, thereby bringing the front curtain  25  to an open position. 
       FIG. 3  is a plan view illustrating a state where the front curtain  25  is located at a closed position in the FP shutter  2 . 
     In the expanded state illustrated in  FIG. 3 , the blades  25   a  to  25   d  cover the opening  15  from one side in the direction of the optical axis P, thereby bringing the front curtain  25  to the closed position. The front curtain  25  is held without power supply at the open position and the closed position by a detent torque of the front curtain electromagnetic actuator  21 . According to the present embodiment, when the power of the optical instrument  1  is turned off, the front curtain  25  is held without power supply at the open position by the detent torque. 
     Rear Curtain Mechanism 
     As illustrated in  FIG. 2 , the rear curtain mechanism  12  is disposed on the other side in the X-direction from the front curtain mechanism  11 . Similarly to the front curtain mechanism  11 , the rear curtain mechanism  12  opens and closes the opening  15  by causing the so-called parallel link to convert pivoting movement around a rear curtain axis O 2  extending along the direction of the optical axis P into slide movement in the X-direction. The rear curtain mechanism  12  is formed so as to be plane-symmetrical to the front curtain mechanism  11  on a plane orthogonal to the X-direction. Therefore, hereinafter, a configuration which is the same as that of the front curtain mechanism  11  will be simply described. 
     The rear curtain mechanism  12  has a rear curtain electromagnetic actuator  51 , a rear curtain drive lever  52 , rear curtain arms (first rear curtain arm  53  and second rear curtain arm  54 ), and a rear curtain  55 . 
     The rear curtain electromagnetic actuator  51  has a rear curtain stator  61  and a rear curtain rotor  62 . 
     The rear curtain stator  61  is equipped with a rear curtain coil  63  for exciting the rear curtain stator  61 . 
     The rear curtain rotor  62  is accommodated inside the rear curtain stator  61 . The rear curtain rotor  62  is configured to be rotatable around the rear curtain axis O 2  extending along the direction of the optical axis P. A rotary shaft  62   a  of the rear curtain rotor  62  faces the sector region after penetrating the substrate  10 . 
     The rear curtain drive lever  52  is coupled to the rear curtain rotor  62 , and pivots around the rear curtain axis O 2  in response to the rotation of the rear curtain rotor  62 . A rear curtain coupling pin  65  extending to one side in the direction of the optical axis P is disposed to protrude in the tip portion of the rear curtain drive lever  52 . The rear curtain coupling pin  65  faces the sector region through a guide groove  66  formed in the substrate  10 . 
     In the first rear curtain arm  53 , the base end portion is coupled to the rear curtain coupling pin  65  and the rotary shaft  62   a  of the rear curtain rotor  62 . 
     In the second rear curtain arm  54 , the base end portion is supported so as to be pivotally movable around a support pin  69  protruding to one side in the direction of the optical axis P from the substrate  10 . 
     The rear curtain  55  has a plurality of (for example, four) blades  55   a  to  55   d . Each of the base end portions of the blades  55   a  to  55   d  is coupled to both the first rear curtain arm  53  and the second rear curtain arm  54  so as to be pivotally movable. In response to the drive of the rear curtain electromagnetic actuator  51 , the blades  55   a  to  55   d  are switched between the overlapped state where the blades  55   a  to  55   d  are overlapped with each other in a plan view and the expanded state (refer to  FIG. 4 ) where the blades  55   a  to  55   d  are expanded in a plan view. In the overlapped state, the blades  55   a  to  55   d  escape from the opening  15  to the other side in the X-direction, thereby bringing the rear curtain  55  to the open position. 
       FIG. 4  is a plan view illustrating a state where the rear curtain  55  is located at the closed position in the FP shutter  2 . 
     In the expanded state illustrated in  FIG. 4 , the respective blades  55   a  to  55   d  cover the opening  15  from one side in the direction of the optical axis P, thereby bringing the rear curtain  55  to the closed position. The rear curtain  55  is held without power supply at the open position and the closed position by the detent torque of the rear curtain electromagnetic actuator  51 . According to the present embodiment, when the power of the optical instrument  1  is turned off, the rear curtain  55  is held without power supply at the open position by the detent torque. The number of the blades  25   a  to  25   d  and  55   a  to  55   d  of the front curtain  25  and the rear curtain  55  is not limited to four, and can be appropriately changed. 
     Here, as illustrated in  FIG. 2 , in the base end portion of the front curtain drive lever  22  and the rear curtain drive lever  52 , a front curtain locking portion  67  and a rear curtain locking portion  68  are integrally formed in the front curtain drive lever  22  and the rear curtain drive lever  52 , respectively. 
     The front curtain locking portion  67  protrudes to the other side in the X-direction from the base end portion of the front curtain drive lever  22 . The front curtain locking portion  67  is formed in a triangular shape in a plan view. Specifically, in the front curtain locking portion  67 , in the circumferential direction around the front curtain axis O 1 , a surface (hereinafter, referred to as a “locking surface  67   a ”) facing in the closing direction of the front curtain drive lever  22  is formed to be a flat surface extending along the radial direction of the front curtain axis O 1 . On the other hand, in the front curtain locking portion  67 , in the circumferential direction around the front curtain axis O 1 , a surface facing in the opening direction of the front curtain drive lever  22  is formed to be a tilting surface whose protruding amount in the radial direction of the front curtain axis O 1  gradually decreases in the opening direction. 
     The rear curtain locking portion  68  protrudes to one side in the X-direction from the base end portion of the rear curtain drive lever  52 . The rear curtain locking portion  68  is formed in a triangular shape in a plan view. Specifically, in the rear curtain locking portion  68 , in the circumferential direction around the rear curtain axis O 2 , a surface (hereinafter, referred to as a “locking surface  68   a ”) facing in the closing direction of the rear curtain drive lever  52  is formed to be a flat surface extending along the radial direction of the rear curtain axis O 2 . On the other hand, in the rear curtain locking portion  68 , in the circumferential direction around the rear curtain axis O 2 , a surface facing in the opening direction is formed to be a tilting surface whose protruding amount in the radial direction of the rear curtain axis O 2  gradually decreases in the opening direction. The front curtain locking portion  67  and the rear curtain locking portion  68  may be formed separately from the front curtain drive lever  22  and the rear curtain drive lever  52 , respectively. 
     Blade Position Holding Mechanism 
     The blade position holding mechanism  13  is disposed between the front curtain mechanism  11  and the rear curtain mechanism  12  in the X-direction. For example, when the power of the optical instrument  1  is turned off, the blade position holding mechanism  13  regulates the movement of the front curtain mechanism  11  and the rear curtain mechanism  12  in the closing direction. Specifically, the blade position holding mechanism  13  mainly has a regulation electromagnetic actuator  71 , a linkage lever  72 , and a regulation lever  73 . The blade position holding mechanism  13  is disposed in the above-described drive region. 
       FIG. 5  is an enlarged plan view illustrating a state where the blade position holding mechanism  13  is located at the entry position in the FP shutter  2 . 
     As illustrated in  FIG. 5 , the regulation electromagnetic actuator  71  has a regulation stator  75  and a regulation rotor  76 . 
     The regulation stator  75  is formed in a cylindrical shape extending in the direction of the optical axis P. The regulation stator  75  is equipped with a regulation coil (not illustrated) for exciting the regulation stator  75 . 
     The regulation rotor  76  is accommodated inside the regulation stator  75 . The regulation rotor  76  is configured to be rotatable around a regulation axis O 3  extending along the direction of the optical axis P. An output of the regulation electromagnetic actuator  71  is smaller than each output of the front curtain electromagnetic actuator  21  and the rear curtain electromagnetic actuator  51 . However, each output of the respective actuators  21 ,  51 , and  71  can be appropriately changed. 
     The linkage lever  72  pivots around the regulation axis O 3  in response to the rotation of the regulation rotor  76 . Specifically, the linkage lever  72  extends toward one side in the Y-direction (direction away from the regulation axis O 3  in the radial direction of the regulation axis O 3 ) in the direction orthogonal to the optical axis P. The base end portion of the linkage lever  72  is coupled to a rotary shaft  76   a  of the regulation rotor  76 . A linkage pin  81  extending to one side in the direction of the optical axis P is disposed to protrude in the tip portion of the linkage lever  72 . 
     The regulation lever  73  is disposed on one side in the Y-direction from the regulation electromagnetic actuator  71 . The regulation lever  73  includes a base portion  82 , a front curtain regulation portion  83 , and a rear curtain regulation portion  84 . 
     The base portion  82  is supported by a support pin  85  protruding to the other side in the direction of the optical axis P from the substrate  10  so as to be pivotally movable around a lever axis O 4  extending along the direction of the optical axis P. In the present embodiment, the front curtain mechanism  11  and the rear curtain mechanism  12  are disposed at positions which are line-symmetrical to a symmetry line extending in the Y-direction through the lever axis O 4  in a plan view. Each position of the front curtain mechanism  11  and the rear curtain mechanism  12  can be appropriately changed. For example, both of these may be disposed at positions which are line-symmetrical to a symmetry line extending in the Y-direction through the regulation axis O 3  in a plane view. 
     The front curtain regulation portion  83  protrudes toward one side in the X-direction from the base portion  82 . In response to the pivoting movement of the regulation lever  73 , the front curtain regulation portion  83  moves between the entry position (refer to  FIG. 5 ) where the front curtain regulation portion  83  enters the operation trajectory of the front curtain locking portion  67  and an escape position (refer to  FIG. 6 ) where the front curtain regulation portion  83  escapes from the operation trajectory of the front curtain locking portion  67 . Specifically, at the entry position, the front curtain regulation portion  83  faces the front curtain locking portion  67  in the closing direction of the front curtain drive lever  22 . In the front curtain regulation portion  83 , a surface (hereinafter, referred to as a “regulation surface  83   a ”) facing the entry position in the circumferential direction around the lever axis O 4  is formed to be a flat surface which can come into contact with the locking surface  67   a  of the front curtain locking portion  67 . That is, at the entry position of the regulation lever  73 , the front curtain regulation portion  83  regulates the movement of the front curtain  25  in the closing direction by the front curtain locking portion  67  of the front curtain mechanism  11  (front curtain drive lever  22 ) coming into contact with the front curtain regulation portion  83 . The front curtain regulation portion  83  is configured to come into contact with the front curtain locking portion  67  before the front curtain  25  approaches the opening  15  in a plan view (open region where the front curtain  25  escapes from the opening  15  in a plan view). 
     In the front curtain regulation portion  83 , a surface facing the escape position in the circumferential direction around the lever axis O 4  is formed to be a tilting surface in which the width of the front curtain regulation portion  83  gradually becomes narrower in a direction toward the tip portion of the front curtain regulation portion  83 . 
       FIG. 6  is an enlarged plan view illustrating a state where the blade position holding mechanism  13  is located at the escape position in the FP shutter  2 . 
     As illustrated in  FIG. 6 , at the escape position, the front curtain regulation portion  83  is located on the other side in the X-direction from the operation trajectory of the front curtain locking portion  67 . That is, at the escape position of the regulation lever  73 , the front curtain regulation portion  83  allows the front curtain mechanism  11  (front curtain drive lever  22 ) to move in the closing direction. 
     As illustrated in  FIG. 5 , the rear curtain regulation portion  84  protrudes toward the other side in the X-direction from the base portion  82 . In response to the pivoting movement of the regulation lever  73 , the rear curtain regulation portion  84  moves between the entry position (refer to  FIG. 5 ) where the rear curtain regulation portion  84  enters the operation trajectory of the rear curtain locking portion  68  and the escape position (refer to  FIG. 6 ) where the rear curtain regulation portion  84  escapes from the operation trajectory of the rear curtain locking portion  68 . Specifically, at the entry position, the rear curtain regulation portion  84  faces the rear curtain locking portion  68  in the closing direction of the rear curtain drive lever  52 . In the rear curtain regulation portion  84 , a surface (hereinafter, referred to as a “regulation surface  84   a ”) facing the escape position in the circumferential direction around the lever axis O 4  is formed to be a flat surface which can come into contact with the locking surface  68   a  of the rear curtain locking portion  68 . That is, at the entry position of the regulation lever  73 , the rear curtain regulation portion  84  regulates the movement of the rear curtain  55  in the closing direction by the rear curtain locking portion  68  of the rear curtain mechanism  12  (rear curtain drive lever  52 ) coming into contact with the rear curtain regulation portion  84 . The rear curtain regulation portion  84  is configured to come into contact with the rear curtain locking portion  68  before the rear curtain  55  approaches the opening  15  in a plan view (open region where the rear curtain  55  escapes from the opening  15  in a plan view). 
     In the rear curtain regulation portion  84 , a surface facing the entry position in the circumferential direction around the lever axis O 4  is formed to be a tilting surface in which the width of the rear curtain regulation portion  84  gradually becomes narrower in a direction toward the tip portion of the rear curtain regulation portion  84 . 
     As illustrated in  FIG. 6 , at the escape position, the rear curtain regulation portion  84  is located on one side in the X-direction from the operation trajectory of the rear curtain locking portion  68 . That is, at the escape position of the regulation lever  73 , the rear curtain regulation portion  84  allows the rear curtain mechanism  12  (rear curtain drive lever  52 ) to move in the closing direction. The regulation lever  73  is held without power supply at each of the entry position and the escape position by the detent torque of the regulation electromagnetic actuator  71 . According to the present embodiment, when the power of the optical instrument  1  is turned off, the regulation lever  73  is held without power supply at the entry position by the detent torque. 
     A biasing member  86  for biasing the regulation lever  73  toward the escape position (one side in the circumferential direction around the lever axis O 4 ) is interposed between the substrate  10  and the regulation lever  73 . 
     A first regulation pin  87  and a second regulation pin  88  which specify a pivoting range of the regulation lever  73  are disposed in the substrate  10 . The first regulation pin  87  is configured so that the front curtain regulation portion  83  can come into contact with the first regulation pin  87  from one side in the circumferential direction around the lever axis O 4 . The first regulation pin  87  regulates the movement of the regulation lever  73  pivoting to one side in the circumferential direction around the lever axis O 4 , and aligns the regulation lever  73  with the escape position. 
     The second regulation pin  88  is configured so that the rear curtain regulation portion  84  can come into contact with the second regulation pin  88  from the other side in the circumferential direction around the lever axis O 4 . The second regulation pin  88  regulates the movement of the regulation lever  73  pivoting to the other side in the circumferential direction around the lever axis O 4 , and aligns the regulation lever  73  with the entry position. As long as a configuration for specifying the pivoting range of the regulation lever  73  is adopted, the respective regulation pins  87  and  88  do not necessarily need to come into contact with the front curtain regulation portion  83  or the rear curtain regulation portion  84 . 
     As illustrated in  FIG. 5 , the base portion  82  has a guide hole  91  into which the linkage pin  81  is loosely inserted. The guide hole  91  is an arc-shaped long hole extending along the circumferential direction around the regulation axis O 3 . Specifically, on the inner peripheral surface of the guide hole  91 , a surface located on one side in the Y-direction from the linkage pin  81  configures a guide surface  92  having a V-shape in a plan view. On the guide surface  92 , a central portion in the circumferential direction around the regulation axis O 3  configures an escape portion  93  escaped to one side in the Y-direction from a pivoting trajectory L of the linkage pin  81  in response to the pivoting movement of the linkage lever  72 . On the other hand, on the guide surface  92 , portions connected to both sides of the escape portion  93  in the circumferential direction around the regulation axis O 3  configure a first sliding contact portion  94  and a second sliding contact portion  95  with which the linkage pin  81  comes into sliding contact when the linkage lever  72  pivots. The sliding contact portions  94  and  95  extend to the other side in the Y-direction (direction closer to the regulation axis O 3  in the radial direction of the regulation axis O 3 ) as both of these are separated from the escape portion  93  in the circumferential direction around the regulation axis O 3 . 
     On the inner peripheral surface of the guide hole  91 , a portion connected to the first sliding contact portion  94  on one side in the circumferential direction around the regulation axis O 3  configures a first contact portion  96  facing the linkage pin  81  in the circumferential direction around the regulation axis O 3 . The first contact portion  96  extends to the other side in the Y-direction from the first sliding contact portion  94 . 
     On the inner peripheral surface of the guide hole  91 , a portion connected to the second sliding contact portion  95  on the other side in the circumferential direction around the regulation axis O 3  configures a second contact portion  97  facing the linkage pin  81  in the circumferential direction around the regulation axis O 3 . The second contact portion  97  extends to the other side in the Y-direction from the second sliding contact portion  95 . In this way, the linkage pin  81  is disposed inside the guide hole  91  while being provided with play in the circumferential direction (pivoting direction of the linkage lever  72 ) around the regulation axis O 3 . Therefore, inside the guide hole  91  according to the present embodiment, clearances between the linkage pin  81  and the sliding contact portions  94  and  95 , and the contact portions  96  and  97  in the circumferential direction around the regulation axis O 3  configure idle running regions where the linkage pin  81  runs idle with respect to the regulation lever  73  in response to the pivoting movement around the regulation axis O 3  of the linkage lever  72 . On the inner peripheral surface of the guide hole  91 , a surface located on the other side in the Y-direction from the linkage pin  81  configures an escape portion  99  separated to the other side in the Y-direction from the linkage pin  81 . 
     Operation 
     Next, an operation according to the present embodiment will be described. Hereinafter, an actuating operation, a stopping operation, and a shutter operation of the optical instrument  1 , and an operation when an impact is input to the optical instrument  1  will be described. In the following description, a state where power is turned off as illustrated in  FIG. 2  is referred to as an initial state. That is, when the power is turned off, both the front curtain  25  and the rear curtain  55  are held without power supply at the open position by the detent torque of the respective electromagnetic actuators  21  and  51 . When the power is turned off, the regulation lever  73  is held without power supply at the entry position by the detent torque. 
     Actuating Operation and Stopping Operation 
     As illustrated in  FIGS. 2 and 5 , during the actuating operation, in a state where the power of the optical instrument  1  is turned off, a user presses a power supply button (not illustrated) of the optical instrument  1 . Then, the power is supplied to a regulation coil (not illustrated) of the regulation electromagnetic actuator  71 , thereby causing the regulation rotor  76  to rotate to one side around the regulation axis O 3  (counterclockwise). When the linkage lever  72  pivots to one side around the regulation axis O 3  in response to the rotation of the regulation rotor  76 , the linkage pin  81  moves to one side around the regulation axis O 3  inside the guide hole  91 . Then, the linkage pin  81  is separated from the second sliding contact portion  95  and the second contact portion  97 , and the linkage pin  81  runs idle inside the guide hole  91  toward the first sliding contact portion  94  and the first contact portion  96 . 
       FIG. 7  is a plan view illustrating a state where the blade position holding mechanism  13  is located at the escape position in the FP shutter  2 . 
     As illustrated in  FIGS. 6 and 7 , when the linkage pin  81  is separated from the second sliding contact portion  95  and the second contact portion  97 , the regulation lever  73  pivots toward the escape position and toward one side around the lever axis O 4  due to a biasing force of the biasing member  86 . Thereafter, the regulation lever  73  (front curtain regulation portion  83 ) comes into contact with the first regulation pin  87  from one side in the circumferential direction around the lever axis O 4 , thereby stopping the pivoting movement of the regulation lever  73 . 
     In this manner, the regulation lever  73  is brought to the escape position illustrated in  FIG. 7 . At the escape position, the front curtain mechanism  11  and the rear curtain mechanism  12  are allowed to move in the closing direction (shutter operation). 
     While the regulation lever  73  moves to the escape position, the linkage pin  81  passes through the escape portion  93 . Thereafter, the linkage pin  81  pivots together with the regulation lever  73  while coming into sliding contact with the first sliding contact portion  94 . Then, when the regulation lever  73  is located at the escape position, the biasing force of the biasing member  86  brings the linkage pin  81  into contact with the first sliding contact portion  94  of the guide hole  91  and the first contact portion  96 , thereby regulating the movement of the regulation lever  73  to the entry position. 
     In the stopping operation, in a state where the power of the optical instrument  1  is turned on, the user presses the power supply button of the optical instrument  1 . Then, the regulation rotor  76  is rotated to the other side around the regulation axis O 3  (clockwise), thereby causing the linkage lever  72  to pivot to the other side around the regulation axis O 3 . At this time, the linkage pin  81  moves to the other side around the regulation axis O 3  inside the guide hole  91 . In this manner, the linkage pin  81  is separated from the first sliding contact portion  94  and the first contact portion  96 , and the linkage pin  81  runs idle inside the guide hole  91  toward the second sliding contact portion  95  and the second contact portion  97 . 
     Thereafter, the linkage pin  81  comes into sliding contact with the second sliding contact portion  95  after passing through the escape portion  93  of the guide hole  91 , thereby causing the regulation lever  73  to pivot together with the linkage lever  72 . At this time, against the biasing force of the biasing member  86 , the regulation lever  73  pivots around the lever axis O 4  toward the entry position. Thereafter, the regulation lever  73  (rear curtain regulation portion  84 ) comes into contact with the second regulation pin  88  from the other side in the circumferential direction around the lever axis O 4 , thereby stopping the pivoting movement of the regulation lever  73 . Then, when the regulation lever  73  stops at the entry position, the linkage pin  81  comes into contact with the second sliding contact portion  95  of the guide hole  91  and the second contact portion  97 , thereby regulating the movement of the regulation lever  73  to the escape position. 
     Shutter Operation 
     When an image is captured, in a state where the power of the optical instrument  1  is turned on, if the user presses a release button (not illustrated), the front curtain  25  moves toward the closed position. Specifically, the power is supplied to the front curtain coil  33  of the front curtain electromagnetic actuator  21 , thereby causing the front curtain rotor  32  to rotate to one side around the front curtain axis O 1  (counterclockwise). In this manner, as illustrated in  FIG. 3 , the front curtain  25  slides and moves in the closing direction (the other side in the X-direction), thereby bringing the respective blades  25   a  to  25   d  into a deployed state. As a result, the front curtain  25  is brought to the closed position, and the opening  15  is closed by the front curtain  25 . 
       FIG. 8  is a plan view illustrating an exposure operation in the FP shutter  2 . 
     Subsequently, the exposure operation illustrated in  FIG. 8  is performed. Specifically, a power supply direction of the front curtain coil  33  is switched, thereby causing the front curtain rotor  32  to rotate to the other side around the front curtain axis O 1  (clockwise). Then, the front curtain  25  slides and moves in the opening direction (one side in the X-direction). After a predetermined time elapses after the front curtain  25  starts to move, the rear curtain  55  is moved toward the closed position. Specifically, similarly to the operation method of the front curtain  25 , the power is supplied to the rear curtain coil  63  of the rear curtain electromagnetic actuator  51 , thereby causing the rear curtain rotor  62  to rotate to one side around the rear curtain axis O 2  (clockwise). In this manner, in a state where a clearance is generated between the front curtain  25  and the rear curtain  55 , the rear curtain  55  slides and moves in the closing direction (one side in the X-direction). At this time, light passes through the clearance between the front curtain  25  and the rear curtain  55 , thereby exposing the imaging element  4 . Then, the front curtain  25  is brought to the open position, and the rear curtain  55  is brought to the closed position, thereby completing the exposure operation. 
     After the exposure operation is completed, the power supply direction of the rear curtain coil  63  is switched, thereby causing the rear curtain rotor  62  to rotate to the other side around the rear curtain axis O 2  (counterclockwise). Then, the rear curtain  55  slides and moves in the other side in the X-direction, thereby causing the rear curtain  55  to return to the open position. 
     According to above-described configuration, the shutter operation is completed. 
     When Impact is Input 
     Subsequently, description will be made on an operation of the FP shutter  2  in a case where an impact load is input to the optical instrument  1  due to dropping in a state where the power of the optical instrument  1  is turned off. Hereinafter, as an example, a case will be described where the optical instrument  1  drops in a state where the front curtain  25  faces downward. 
     First, as illustrated in  FIG. 2 , in a state where the power of the optical instrument  1  is turned off, both the front curtain  25  and the rear curtain  55  are located at the open position, and the regulation lever  73  of the blade position holding mechanism  13  is located at the entry position. In this state, if the impact load is input to the optical instrument  1 , the front curtain  25  tends to be unexpectedly slid and moved in the closing direction (the other side in the X-direction). Then, in response to the slide movement of the front curtain  25 , the front curtain rotor  32  and the front curtain drive lever  22  tend to pivot toward one side around the front curtain axis O 1 . 
     Then, as illustrated in  FIG. 5 , the front curtain locking portion  67  (locking surface  67   a ) of the front curtain drive lever  22  comes into contact with the front curtain regulation portion  83  (regulation surface  83   a ) from the other side around the front curtain axis O 1 . In this manner, the pivoting movement of the front curtain drive lever  22  to one side around the front curtain axis O 1  is regulated, thereby regulating the slide movement of the front curtain  25  in the closing direction. 
     If the impact load is input to the optical instrument  1 , due to the inertia, the rear curtain  55  tends to be unexpectedly slid and moved in the closing direction (one side in the X-direction). Then, in response to the slide movement of the rear curtain  55 , the rear curtain rotor  62  and the rear curtain drive lever  52  tend to pivot toward one side around the rear curtain axis O 2 . Then, the rear curtain locking portion  68  (locking surface  68   a ) of the rear curtain drive lever  52  comes into contact with the rear curtain regulation portion  84  (regulation surface  84   a ) from the other side around the rear curtain axis O 2 . In this manner, the pivoting movement of the rear curtain drive lever  52  to one side around the rear curtain axis O 2  is regulated, thereby regulating the slide movement of the rear curtain  55  in the closing direction. As a result, it is possible to restrain the front curtain  25  and the rear curtain  55  from entering the opening  15  in a plan view. After the slide movement of the front curtain  25  and the rear curtain  55  in the X-direction is regulated by the blade position holding mechanism  13 , the front curtain  25  and the rear curtain  55  are caused to return to the initial state by the detent torque of the respective electromagnetic actuators  21  and  51 . 
     Here, since the electromagnetic actuators  21  and  51  rotate in mutually opposite directions, the front curtain  25  and the rear curtain  55  respectively slide and move in the closing direction. In this case, when the above-described impact load is input, the front curtain  25  (front curtain locking portion  67 ) comes into contact with the front curtain regulation portion  83  from the other side in the circumferential direction around the lever axis O 4 . Accordingly, the regulation lever  73  tends to pivot to one side around the lever axis O 4 . The rear curtain  55  (rear curtain locking portion  68 ) comes into contact with the rear curtain regulation portion  84  from one side in the circumferential direction around the lever axis O 4 . Accordingly, the regulation lever  73  tends to pivot to the other side around the lever axis O 4 . Therefore, the pivoting operation of the regulation lever  73  toward the escape position, which is performed by the front curtain locking portion  67  coming into contact with the front curtain regulation portion  83 , is cancelled by the pivoting operation of the regulation lever  73  toward the entry position, which is performed by the rear curtain locking portion  68  coming into contact with the rear curtain regulation portion  84 . Therefore, the regulation lever  73  can maintain the entry position easily. 
     For example, in a case where the impact load input to the optical instrument  1  is small, only the front curtain  25  tends to move in the closing direction in some cases. In this case, it is difficult to think that the impact load is input to such an extent as to move the regulation lever  73  to the escape position. Therefore, even if the regulation lever  73  tends to pivot toward the escape position, the regulation lever  73  stays at the entry position due to the detent torque of the regulation electromagnetic actuator  71 . 
     In this way, the present embodiment adopts a configuration in which the linkage pin  81  of the linkage lever  72  is loosely inserted into the guide hole  91  of the regulation lever  73  (engagement with play). 
     According to this configuration, when the linkage lever  72  pivots, the linkage pin  81  runs idle inside the guide hole  91  until the linkage pin  81  comes into contact with the sliding contact portions  94  and  95 , and the contact portions  96  and  97 . Therefore, it is possible to reduce a load torque applied to the regulation electromagnetic actuator  71 . In this manner, miniaturization of the regulation electromagnetic actuator  71  can be achieved, and less power consumption of the FP shutter  2  can be achieved. According to the present embodiment, the linkage pin  81  is inserted loosely into the guide hole  91 . Accordingly, compared with a case where the linkage lever  72  is interlocked with the rotation operation of the regulation electromagnetic actuator  71 , it is possible to minimize the pivoting range of the regulation lever  73  with respect to an actuation angle of the regulation electromagnetic actuator  71 . In this manner, the regulation electromagnetic actuator  71  can be more freely selected, and the regulation lever  73  can easily be set in a desired pivoting range with respect to the actuation angle of the regulation electromagnetic actuator  71 . In this regard, the FP shutter  2  can be more freely designed. 
     The present embodiment adopts a configuration in which at the entry position, the regulation lever  73  can be locked by both the front curtain locking portion  67  and the rear curtain locking portion  68  so as to regulate the movement of the front curtain  25  and the rear curtain  55  in the closing direction. 
     According to this configuration, it is possible to restrain the front curtain  25  and the rear curtain  55  from being unexpectedly moved in the closing direction due to a drop impact. In this manner, it is not necessary to increase the detent torque of the electromagnetic actuators  21  and  51  in order to hold the front curtain  25  and the rear curtain  55  at the open position. Therefore, a miniaturized device, a quickened shutter operation, and impact resistance can be realized. 
     According to the present embodiment, the guide hole  91  has the escape portion  93  which escapes from the contact with the linkage pin  81  in the Y-direction. Accordingly, it is possible to reliably reduce the load torque applied to the regulation electromagnetic actuator  71 . 
     According to the present embodiment, the FP shutter  2  has the biasing member  86  that biases the regulation lever  73  toward the escape position. Accordingly, it is possible to restrain rattling of the regulation lever  73 . Therefore, it is possible to restrain the shutter operation from being hindered by the regulation lever  73  after the regulation lever  73  unexpectedly enters the entry position. 
     According to the present embodiment, it is possible to reliably restrain the front curtain  25  and the rear curtain  55  from entering the inside of the opening  15  in a plan view. Therefore, for example, it is possible to reliably restrain the front curtain  25  or the rear curtain  55  from appearing on a monitor (not illustrated) of the optical instrument  1 . In addition, it is possible to minimize a movement amount of the front curtain  25  and the rear curtain  55 . Therefore, even in a case where the front curtain  25  and the rear curtain  55  are moved in the closing direction due to an impact load, the front curtain  25  and the rear curtain  55  are made to easily return to the initial state by the detent torque. 
     According to the present embodiment, the movement of the front curtain  25  and the rear curtain  55  in the closing direction can be regulated by the single blade position holding mechanism  13 . Therefore, compared with a case where the blade position holding mechanism is disposed in each of the front curtain  25  and the rear curtain  55 , the FP shutter  2  can be miniaturized. 
     The present embodiment adopts a configuration in which the front curtain  25  and the rear curtain  55  respectively have the plurality of blades  25   a  to  25   d  and  55   a  to  55   d.    
     According to this configuration, the plurality of blades  25   a  to  25   d  and  55   a  to  55   d  are held at the open position in the overlapped state. Therefore, for example, compared with a case where a single blade opens and closes the opening  15 , the respective blades can be miniaturized. 
     The optical instrument  1  according to the present embodiment includes the above-described FP shutter  2 . Therefore, it is possible to provide the optical instrument  1  which is miniaturized and requires less power consumption while impact resistance is ensured. 
     The technical scope of the invention is not limited to the above-described embodiment, and various modifications can be added thereto within the scope not departing from the gist of the invention. 
     For example, in the above-described embodiment, a case has been described where the locking portions  67  and  68  are disposed in the drive levers  22  and  52 , but the invention is not limited to only this configuration. For example, the locking portions  67  and  68  may be disposed in members interlocking with the front curtain  25  and the rear curtain  55 , such as the arms  23 ,  24 ,  53 , and  54 , or the blades  25   a  to  25   d  and  55   a  to  55   d.    
     In the above-described embodiment, a configuration has been described in which the locking portions  67  and  68 , and the regulation portions  83  and  84  come into contact with each other before the front curtain  25  and the rear curtain  55  approach the opening  15 . However, the invention is not limited to only this configuration. 
     In the above-described embodiment, a configuration has been described in which the regulation lever  73  is switched from the entry position to the escape position in a case where a power-off state is switched to a power-on state. However, without being limited to only this configuration, the operation method of the regulation lever  73  can be appropriately changed. For example, a configuration may be adopted in which at timing of pressing the release button, the regulation lever  73  is switched from the entry position to the escape position. 
     In the above-described embodiment, a configuration has been described in which in response to the pivoting operation of the regulation lever  73 , the regulation lever  73  is switched between the entry position and the escape position. However, the invention is not limited to only this configuration. For example, a configuration may be adopted in which in response to the slide movement of the regulation lever  73 , the regulation lever  73  is switched from the entry position to the escape position. 
     In the above-described embodiment, a configuration has been described in which the regulation lever  73  is biased toward the escape position by the biasing member  86 . However, the invention is not limited to only this configuration. That is, a configuration may be adopted in which only power of the regulation electromagnetic actuator  71  causes the regulation lever  73  to pivot toward the escape position. 
     In the above-described embodiment, a configuration has been described in which the front curtain  25  and the rear curtain  55  are actuated using the electromagnetic actuators  21  and  51 . However, without being limited to only this configuration, any actuator other than the electromagnetic actuators  21  and  51  may be used. 
     In the above-described embodiment, a configuration has been described in which the movement of both the front curtain  25  and the rear curtain  55  in the closing direction is regulated using the single regulation lever  73 . However, the invention is not limited to only this configuration. For example, a configuration may be adopted in which the movement of at least any one of the front curtain  25  and the rear curtain  55  in the closing direction is regulated by the regulation lever (blade position holding member). In addition, the regulation lever (blade position holding member) may be disposed so as to correspond to each of the front curtain  25  and the rear curtain  55 . 
     In the above-described embodiment, a configuration has been described in which the linkage pin  81  of the linkage lever  72  is loosely inserted into the guide hole  91  of the regulation lever  73 . However, without being limited to only this configuration, any configuration may be adopted as long as the linkage lever  72  and the regulation lever  73  engage with each other while being provided with play in the pivoting direction of the linkage lever  72  pivoting around the regulation axis O 3 . In this case, for example, a configuration may be adopted in which a pin formed in the regulation lever  73  is loosely inserted into a guide hole formed in the linkage lever  72 . In addition, an engagement method between the linkage lever  72  and the regulation lever  73  is not limited to the hole and the pin. 
     Alternatively, within the scope not departing from the gist of the invention, the configuration elements in the above-described embodiment can be appropriately replaced with known configuration elements. In addition, the above-described respective modification examples may be appropriately combined with each other.