JP2007212645A - Light control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a shutter blade and an aperture blade into and out of an exposure opening by a single driving means.
SOLUTION: By driving a stepping motor to three positions, a shutter blade is driven to three positions by a driving lever fixed to the stepping motor, and an aperture blade is provided with an allowance by a long hole for interlocking with the driving lever. And is driven to 2 positions. With this combination, it is possible to selectively drive the shutter blades in and out of the exposure opening and the diaphragm blades in and out of the exposure opening.
[Selection] Figure 1

Description

  The present invention relates to a light quantity control device having a shutter mechanism and a light quantity adjustment mechanism.

  Conventionally, as a light amount control device having a shutter mechanism and a light amount adjustment mechanism, there is a motor control shutter device described in Patent Document 1. This includes a motor that is controlled by a control circuit to perform forward and reverse rotation, a sector that opens and closes the shutter opening, and a diaphragm opening that is smaller in diameter than the shutter opening. A small diaphragm plate that moves between a second position for retreating from the rotor and a rotor actuating member that is actuated by a motor to actuate the sector or the small diaphragm plate. The rotor actuating member is a sector in the first operating region. And the sector and the small diaphragm plate are selectively operated according to the operation region so that the small diaphragm plate is moved in the second operation region different from the first operation region. .

  Further, there is an imaging device described in Patent Document 2. This operates between an imaging optical system, imaging means, a ground plane having an exposure opening, a first position having an opening smaller than the exposure opening and retracting from the exposure opening and a second position entering the exposure opening. Possible diaphragm blade member, shutter blade member operable between a first position retracted from the exposure opening and a second position entering the exposure opening, diaphragm blade driving means for driving the diaphragm blade member, and shutter blade Shutter blade driving means for driving the member, first holding means for holding the diaphragm blade member at the first position and the second position when no power is supplied, and the first position and the second position of the shutter blade member. It is comprised with the 2nd holding | maintenance means hold | maintained at each position at the time of no electricity supply.

  There is also a shutter device with a diaphragm mechanism described in Patent Document 3. This comprises a shutter blade that opens and closes the opening, and a diaphragm aperture plate that restricts the opening to a predetermined diameter. The shutter blade is driven by a single drive source, and the drive force of this single drive source is varied. By transmitting to the diaphragm aperture plate by the moving lever and setting the timing for moving the diaphragm aperture plate to the retracted position and the retracted position by the relationship between the connecting hole formed in the swing lever and the drive pin of the drive source and the holding spring. The aperture operation and the exposure operation are performed with a single drive source.

There is also a shutter for a digital camera described in Patent Document 4. This includes a shutter blade that opens and closes an exposure opening, a diaphragm member having an opening having a smaller diameter than the exposure opening, a motor in which the rotation direction of the rotor can be changed by the energization direction and the applied voltage can be switched, and a motor Driving means that can be reciprocated from the initial position by means of the above, and when a low voltage is applied to the motor, the forward movement from the initial position of the driving means is stopped halfway to maintain the closed state of the exposure opening by the shutter blades. And a control member that is actuated against the biasing force of the spring by a forward movement from the initial position of the driving means when a high voltage is applied to the motor, and the control member operates against the biasing force of the spring. In this case, the aperture member is actuated from the initial position, the opening is inserted into the exposure opening, and the state is held by the holding means. It is intended to release the. That is, the shutter blade drive and the diaphragm member drive can be selectively performed by switching the voltage applied to the motor.
Japanese Patent No. 3208536 Japanese Patent No. 3205714 JP 2002-139767 A JP 2002-202544 A

  However, the one proposed in Patent Document 1 can selectively drive the sector or the small diaphragm plate according to the operating region of the rotor operating member operated by the motor, but the small diaphragm plate is the shutter. Since holding means such as an electromagnet or a ratchet mechanism for holding the first position in the opening is required, the configuration is complicated, the cost is high, and miniaturization is difficult.

  In addition, what is proposed in Patent Document 2 is provided with dedicated drive means for each of the diaphragm blade member and the shutter blade member, so that the cost is high and the drive means requires a lot of space. .

  In addition, what is proposed in Patent Document 3 is to drive the shutter blade and the diaphragm aperture plate with a single drive source, but the swing for moving the diaphragm aperture plate in and out at a predetermined timing. Since a lever and a holding spring are required, the configuration is complicated, the cost is high, and downsizing is difficult. Further, in order to drive the swing lever, a force sufficient to resist the holding spring is required, and the drive source becomes large.

  In addition, what is proposed in Patent Document 4 is to selectively drive the shutter blades and the diaphragm member by switching the voltage applied to the motor. However, a control member and holding means are required for this purpose. Therefore, the configuration becomes complicated, the cost is high, it is difficult to reduce the size, and the motor also requires high torque. In order to increase the shutter closing speed, it is effective to increase the applied voltage, but there is a drawback that the aperture member is automatically inserted when the applied voltage is increased.

(Object of invention)
An object of the present invention is to provide a light amount control device having a shutter mechanism and a light amount adjustment mechanism which are small and have a simple configuration.

  In order to achieve the above object, the present invention according to claim 1 is capable of rotating between a light amount regulating member having an exposure opening, and a position where the light amount regulating member is inserted into the exposure opening and a retracted position. A first blade, a second blade that can be rotated between an insertion position of the light amount regulating member into the exposure opening and a retracted position, a first position, a second position, and a third position. Driving means for driving the first blade and the second blade by switching between the first blade and the second blade at the first position of the driving means. Driven to the retracted position, at the third position of the driving means, the first blade is driven to the retracted position, the second blade is driven to the insertion position, and the driving means is moved from the first position to the second position. When moved, the first blade is driven to the insertion position, and the second blade is driven to the retracted position. Stage 3 of the first blade when moved to the second position from the position the insertion position, the second blade is to the light quantity control device, characterized in that it is driven in the insertion position.

  According to the first aspect of the present invention, the first blade and the second blade are selectively driven by the single driving means to the insertion position into the exposure opening and the retracted position from the exposure opening, respectively. It becomes possible.

  According to a second aspect of the present invention, there is provided a light amount regulating member having an exposure opening, and an interval between an insertion position for shielding the exposure opening of the light quantity regulating member and a retreat position for retreating from the exposure opening. A movable shutter blade, and a light amount adjusting blade rotatable between an insertion position for adjusting a light amount passing through the exposure opening of the light amount regulating member to a predetermined amount and a retracted position for retracting from the exposure opening. Driving means for driving the shutter blade and the light amount adjusting blade by switching to a first position, a second position, and a third position, and the shutter blade at the first position of the driving means. Is driven to the retracted position, and the light quantity adjusting blade is driven to the retracted position. At the third position of the driving means, the shutter blade is driven to the retracted position, the light quantity adjusting blade is driven to the inserted position, and the driving means is moved to the first position. Move to second position from The shutter blade is driven to the insertion position and the light amount adjustment blade is driven to the retracted position. When the driving means is moved from the third position to the second position, the shutter blade is inserted and the light amount adjustment blade is inserted. The light quantity control device is driven to a position.

  According to a third aspect of the present invention, there is provided a light quantity control device having two retracted positions of the shutter blades.

  According to a fourth aspect of the present invention, the light quantity adjusting blade is a light quantity control device that interlocks with the driving means with a predetermined allowance.

  According to a fifth aspect of the present invention, the drive means is a light quantity control device including a stepping motor and a drive lever.

  According to the second to fifth aspects of the present invention, the shutter blade and the light amount adjusting blade are inserted into the exposure opening and the exposure opening from the exposure opening by a single driving means including a stepping motor and a drive lever, respectively. It is possible to selectively drive to the retracted position.

  Further, since the shutter blade and the light amount adjusting blade can be positioned without using an urging member such as a spring, the necessary torque of the stepping motor as the driving means may be a torque for moving the shutter blade and the light amount adjusting blade. For this reason, the stepping motor can be significantly reduced in size.

  Further, compared with those proposed in Patent Documents 1 to 4, the structure is simple and the number of components is small, and the cost can be reduced.

  Further, since the light amount adjusting blade does not move during the shutter blade closing operation, only the shutter blade is loaded on the stepping motor, and the shutter closing time can be increased.

  As described above, according to the present invention, it is possible to provide a light amount control apparatus having a shutter mechanism and a light amount adjusting mechanism that are small and have a simple configuration.

  Hereinafter, the present invention will be described in detail based on illustrated embodiments.

  FIG. 1 is an exploded perspective view of a light quantity control device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a stepping motor that is a component of the light quantity control device of FIG.

  In these drawings, 1 is a stepping motor, 2 is a drive lever fixed to an output shaft portion 13a (described later) of the stepping motor 1, and the drive lever 2 is provided with an output pin 2a.

  Reference numeral 3 denotes a ground plate provided with an opening 3a in the center. A stepping motor 1 is attached to the base plate 3, and an output pin 2a of the drive lever 2 protrudes to the opposite side through the elongated hole 3c. The main plate 3 is integrally provided with a shaft dowel 3b, a stopper 3b, a stopper 3e, and a stopper 3f.

  Reference numeral 4 denotes a shutter blade having a light shielding portion 4 a having a diameter larger than that of the opening 3 a of the base plate 3. The shutter blade 4 is fitted on the shaft dowel 3 b of the base plate 3 so that the shaft hole 4 b is rotatable, Be placed. The shutter blade 4 has a hole 4c, and the output pin 2a of the drive lever 2 is rotated by fitting into the hole 4c. Further, the shutter blade 4 is provided with a protrusion 4d, and is rotatable about the shaft dowel 3b from a state where the protrusion 4d is in contact with the stopper 3d of the base plate 3 to a state where it is in contact with the stopper 3f.

  Reference numeral 5 denotes an intermediate sheet, and the intermediate sheet 5 is provided with an opening 5a having a slightly smaller diameter than the opening 3a of the base plate 3 at the center. The intermediate sheet 5 is fixed to the base plate 3 with the shutter blades interposed therebetween.

  6 is a diaphragm blade provided with an opening 6a having a diameter smaller than that of the opening 5a of the intermediate sheet 5, and the diaphragm blade 6 has a shaft hole 6b rotatably fitted to a shaft dowel 3b of the base plate 3, Arranged on the intermediate sheet 5. The aperture blade 6 has a long hole 6c, and the output pin 2a of the drive lever 2 is rotated by coming into contact with the end of the long hole 6c. Further, the diaphragm blade 6 is provided with a projection 6d, and is rotatable about the shaft dowel 3b from a state in which the projection 6d is in contact with the stopper 3d of the base plate 3 to a state in which it is in contact with the stopper 3e.

  Reference numeral 7 denotes a blade presser that prevents the shutter blade 4, the intermediate sheet 5, and the aperture blade 6 from coming off from the base plate 3. The blade retainer 7 is provided with an opening 7 a having a larger diameter than the opening 5 a of the intermediate sheet 5 at the center.

  The center of the opening 3a of the base plate 3, the opening 5a of the intermediate sheet 5, and the opening 7a of the blade retainer 7 are arranged substantially coincident with each other.

  8 to 15 are components of the stepping motor 1, and 8 is a stator made of a soft magnetic material. The first outer magnetic pole portion 8a, the second outer magnetic pole portion 8b, the first outer magnetic pole portion 8a, and A flat plate portion 8c that connects one end of each of the second outer magnetic pole portions 8b and a bearing mounting portion 8d for mounting a bearing 14 described later are provided. The first outer magnetic pole portion 8a and the second outer magnetic pole portion 8b are formed in a comb-like shape extending in a direction parallel to the rotor shaft 13 described later.

  9 is a first coil, 10 is a second coil, 11 is a bobbin around which the first coil 9 and the second coil 10 are wound, and the first coil 9 is fixed to the bobbin 11 with a first on its inner periphery. The outer magnetic pole portion 8a is fixed so as to be disposed, and the second coil 10 is fixed so that the second outer magnetic pole portion 8b is disposed on the inner periphery thereof while being fixed to the bobbin 11. The first outer magnetic pole portion 8a is excited by energizing the first coil 9, and the second outer magnetic pole portion 8b is excited by energizing the second coil 10. Since the first coil 9 and the second coil 10 are disposed adjacent to each other on the plane of the flat plate portion 8c of the stator 8, the length in the axial direction of the motor can be shortened.

  Reference numeral 12 denotes a cylindrical magnet made of a permanent magnet, and the magnet 12 is divided into multiple parts in the circumferential direction, that is, the number of magnetic poles is N (in this embodiment, six parts are divided, that is, N = 6). ) S pole and N pole are alternately magnetized. The inner peripheral surface of the magnet 12 has a weak magnetization distribution as compared with the outer peripheral surface, or is not magnetized at all, or a pole opposite to the outer peripheral surface, that is, the outer peripheral surface is an S pole. The inner peripheral surface is any one that is magnetized to the N pole.

  Reference numeral 13 denotes a rotor shaft made of a soft magnetic material, and a part of the outer peripheral surface of the rotor shaft 13 and the inner peripheral surface of the magnet 12 are firmly fixed by adhesion, press fitting, or the like. The rotor shaft 13 is formed with an output shaft portion 13a and a holding shaft portion 13b. The rotor shaft 13 is rotatably supported by a bearing 14 attached to a bearing attaching portion 8d of the stator 8 and a shaft holding portion 15a provided integrally with a cover 15 described later. Is done.

  The first outer magnetic pole portion 8a and the second outer magnetic pole portion 8b are arranged to face the outer peripheral surface of the magnet 12 with a predetermined gap. A first inner magnetic pole portion is formed at a portion facing the first outer magnetic pole portion 1 a and the first coil 9 of the rotor shaft 13. Similarly, a second inner magnetic pole portion is formed at a portion facing the second outer magnetic pole portion 8 b and the second coil 10 of the rotor shaft 13.

  When the first coil 9 is energized, the first outer magnetic pole portion 8a and the first inner magnetic pole portion are excited, and a magnetic flux crossing the magnet 12 is generated between the magnetic poles. Works. At that time, the first outer magnetic pole portion 8a and the first inner magnetic pole portion are excited to opposite poles. Similarly, when the second coil 10 is energized, the second outer magnetic pole portion 8b and the second inner magnetic pole portion are excited, and a magnetic flux crossing the magnet 12 is generated between the magnetic poles. Act on. At that time, the second outer magnetic pole portion 8b and the second inner magnetic pole portion are excited to opposite poles.

  A cover 15 is fixed to the stator 8. Reference numeral 15a denotes a shaft holding portion, and the output shaft portion 13a of the rotor shaft 13 is fitted and the rotor shaft 13 is rotatably supported.

  3 to 5 are top views showing the phase relationship among the magnet 12, the stator 8, and the drive lever 2 of the stepping motor 1. FIG. As can be seen from these figures, the magnet 12 has a magnetized portion in which the outer peripheral surface is uniformly divided into multiple pieces in the circumferential direction (in this embodiment, divided into six) and the S pole and the N pole are alternately magnetized. Is formed. Further, the phase difference between the first outer magnetic pole portion 8a and the second outer magnetic pole portion 8b facing the magnet 12 is 180 / N degrees (30 degrees in this embodiment), where N is the number of magnetized magnetic poles of the magnet 12. It is shifted and opposed.

  Next, the phase relationship between the magnet 12 and the first outer magnetic pole portion 8a and the second outer magnetic pole portion 8b of the stator 8 will be described with reference to FIGS.

  When the first outer magnetic pole portion 8 a is excited to the S pole by positively energizing the first coil 9 as shown in FIG. 3, the magnet 12 has a center of the first outer magnetic pole portion 8 a and a magnetized portion of the magnet 12. A counterclockwise rotational force is generated so that the centers of the electrodes (the centers of the N poles) coincide with each other. At the same time, the second coil 10 is positively energized to excite the second outer magnetic pole portion 8b to the S pole. Then, a rotational force in the clockwise direction in the figure is generated in the magnet 12 so that the center of the second outer magnetic pole portion 8b coincides with the center of the magnetized portion of the magnet 12 (the center of the N pole). During energization, it stops in a state where the rotational force is balanced. When this state is the state of FIG. 3 and the energization amounts to both coils are equal, the phase difference between the center of the first outer magnetic pole portion 8a and the center of the magnetized portion of the magnet 12 (the center of the N pole) and The phase difference between the center of the second outer magnetic pole portion 8b and the center of the magnetized portion of the magnet 12 (the center of the N pole) is about 15 degrees. Further, this state coincides with the non-energized cogging stop position of the stepping motor 1, and here, even if the first coil 9 and the second coil 10 are de-energized, this state is maintained by the cogging force.

  When the first coil 9 is switched to reverse energization from the state of FIG. 3, the first outer magnetic pole portion 8 a is excited to the N pole, and the magnet 12 is attached to the center of the first outer magnetic pole portion 8 a and the magnet 1. A clockwise rotational force in the figure is generated so that the centers of the magnetic parts (the centers of the S poles) coincide with each other. Here, the second coil 10 is kept positively energized, so that the center of the second outer magnetic pole portion 8b and the center of the magnetized portion of the magnet 12 (the center of the N pole) coincide with the magnet 12. Similarly, a clockwise rotational force is generated, and the clockwise rotation is started from the state shown in FIG.

  When rotating about 15 degrees in the clockwise direction from the state of FIG. 3, the center of the second outer magnetic pole portion 8b and the center of the magnetized portion of the magnet 12 (the center of the N pole) coincide with each other. The center of the outer magnetic pole portion 8a coincides with the boundary between the magnetized portions of the magnet 12 (the boundary between the S pole and the N pole), and a force for rotating counterclockwise is generated. Then, when it further rotates about 15 degrees clockwise from that state (rotates about 30 degrees clockwise from the state of FIG. 3), the rotational force of both coils is balanced, and it stops at that position. This state is the state of FIG. That is, when the magnet 12 rotates from the state of FIG. 3 to the state of FIG. 4, the drive lever 2 rotates 30 degrees. Further, this state coincides with the non-energized cogging stop position of the stepping motor 1, and here, even if the first coil 9 and the second coil 10 are de-energized, this state is maintained by the cogging force.

  When the second coil 10 is switched to reverse energization from the state of FIG. 4, the second outer magnetic pole portion 8 b is excited to the N pole, and the magnet 12 is attached to the center of the second outer magnetic pole portion 8 b and the magnet 12. A clockwise rotational force in the figure is generated so that the centers of the magnetic parts (the centers of the S poles) coincide with each other. Here, the first coil 9 is kept reversely energized so that the center of the first outer magnetic pole portion 8a and the center of the magnetized portion of the magnet 12 (the center of the S pole) coincide with the magnet 12. Similarly, a clockwise rotational force is generated, and the clockwise rotation starts from the state shown in FIG.

  When rotating about 15 degrees clockwise from the state of FIG. 4, the center of the first outer magnetic pole portion 8a and the center of the magnetized portion of the magnet 12 (the center of the S pole) coincide with each other. The center of the outer magnetic pole portion 8b coincides with the boundary between the magnetized portions of the magnet 12 (the boundary between the S pole and the N pole), and a force for rotating in the clockwise direction is generated. Then, when it further rotates about 15 degrees clockwise from that state (rotates about 30 degrees clockwise from the state of FIG. 4), the rotational force of both coils becomes balanced, and it stops at that position. This state is the state of FIG. That is, when the magnet 12 rotates from the state of FIG. 4 to the state of FIG. 5, the drive lever 2 rotates 30 degrees. Further, this state coincides with the non-energized cogging stop position of the stepping motor 1, and here, even if the first coil 9 and the second coil 10 are de-energized, this state is maintained by the cogging force.

  The case of rotating clockwise from the state of FIG. 3 to the state of FIG. 4 to the state of FIG. 5 has been described above, but the same applies to the case of rotating counterclockwise in the reverse order. As described above, by controlling the energization states of the first coil 9 and the second coil 10, the state of FIG. 3, the state of FIG. 4, and the state of FIG. 5 can be arbitrarily selected.

  6 to 9 are top views showing the states of the shutter blades and the diaphragm blades, and FIG. 10 is a table showing the relationship between the motor energization and the shutter blades and the diaphragm blades. The manner of driving the shutter blades and diaphragm blades by the drive lever will be described. 6 to 9 omit the intermediate sheet 5 for easy understanding.

  FIG. 6 shows the state of the shutter blades and the diaphragm blades when the stepping motor 1 is in the state shown in FIG. By positively energizing the first coil 9 and the second coil 10, the drive lever 2 stops in the state shown in FIG. At this time, the shutter blade 4 is positioned in a state in which the hole 4c is engaged with the output pin 2a of the drive lever 2 and the protrusion 4d is in contact with the stopper 3d of the base plate 3. The diaphragm blade 6 is positioned in a state in which the left end portion of the elongated hole 6c and the output pin 2a of the drive lever 2 are in contact with each other, and the protruding portion 6d is in contact with the stopper 3d of the base plate 3. In this state, the shutter blade 4 and the diaphragm blade 6 are retracted from the opening 3 a of the base plate 3. That is, it is also in a state of being retracted from the opening 5a of the intermediate sheet 5 (not shown) that is slightly smaller in diameter than the opening 3a of the base plate 3. At this time, the opening for exposure is determined by the opening 5 a of the intermediate sheet 5. Even when the power to the stepping motor 1 is turned off, this state is maintained.

  FIG. 7 shows the state of the shutter blade and the aperture blade when the stepping motor 1 is switched from the state of FIG. 3 to the state of FIG. By reversely energizing the first coil 9 and positively energizing the second coil 10, the drive lever 2 rotates from the state of FIG. 3 to the state of FIG. 4 and stops. At this time, the hole 4c of the shutter blade 4 is engaged with the output pin 2a of the drive lever 2 and is positioned at the phase position of the drive lever 2. Further, the diaphragm blade 6 is in a state where the right end portion of the elongated hole 6c and the output pin 2a of the drive lever 2 are substantially in contact with each other, but even if the drive lever 2 rotates from the state of FIG. 3 to the state of FIG. The output pin 2a of the drive lever 2 simply rotates in the elongated hole 6c, does not act on the aperture blade 6, and is positioned while the projection 6d is in contact with the stopper 3d of the base plate 3. Here, when the shutter blade 4 rotates, the diaphragm blade 6 may also move due to friction. However, by installing an intermediate sheet 5 (not shown) between the shutter blade 4 and the diaphragm blade 6, the shutter blade 4. This prevents the diaphragm blades from being affected by friction when rotating. In this state, the shutter blade 4 completely covers the opening 3 a of the base plate 3, and the aperture blade 6 is retracted from the opening 3 a of the base plate 3. That is, the opening 5a of the intermediate sheet 5 (not shown) having a slightly smaller diameter than the opening 3a of the base plate 3 is also completely shielded from light. Further, the diaphragm blade 6 may rotate in the clockwise direction in the drawing due to vibration or impact, but the shutter blade 4 is positioned in a state where the opening 5a of the intermediate sheet 5 (not shown) is completely shielded from light. There is no adverse effect. Even when the power to the stepping motor 1 is turned off, this state is maintained.

  FIG. 8 shows the state of the shutter blades and diaphragm blades when the stepping motor 1 is in the state of FIG. By reversely energizing the first coil 9 and the second coil 10, the drive lever 2 stops in the state shown in FIG. At this time, the shutter blade 4 is positioned in a state in which the hole 4c is engaged with the output pin 2a of the drive lever 2 and the protrusion 4d is in contact with the stopper 3f of the base plate 3. The diaphragm blade 6 is positioned in a state in which the right end portion of the elongated hole 6c and the output pin 2a of the drive lever 2 are in contact with each other, and the projection 6d is in contact with the stopper 3e of the base plate 3. In this state, the shutter blade 4 is retracted from the opening 3 a of the base plate 3, and the aperture blade 6 is inserted into the opening 3 a of the base plate 3. That is, the opening 5 a of the intermediate sheet 5 (not shown) having a slightly smaller diameter than the opening 3 a of the base plate 3 is covered with the aperture blade 6. At this time, the opening for exposure is determined by the opening 6 a of the diaphragm blade 6 having a smaller diameter than the opening 5 a of the intermediate sheet 5. Even when the power to the stepping motor 1 is turned off, this state is maintained.

  FIG. 9 shows the state of the shutter blade and the aperture blade when the stepping motor 1 is switched from the state of FIG. 5 to the state of FIG. By reversely energizing the first coil 9 and positively energizing the second coil 10, the drive lever 2 rotates from the state of FIG. 5 to the state of FIG. 4 and stops. At this time, the hole 4c of the shutter blade 4 is engaged with the output pin 2a of the drive lever 2 and is positioned at the phase position of the drive lever 2. Further, the diaphragm blade 6 is in a state where the left end portion of the elongated hole 6c and the output pin 2a of the drive lever 2 are substantially in contact with each other, but even if the drive lever 2 rotates from the state of FIG. 5 to the state of FIG. The output pin 2a of the drive lever 2 only rotates in the elongated hole 6c, does not act on the aperture blade 6, and is positioned while the projection 6d is in contact with the stopper 3e of the base plate 3. Here, when the shutter blade 4 rotates, the diaphragm blade 6 may also move due to friction. However, by installing an intermediate sheet 5 (not shown) between the shutter blade 4 and the diaphragm blade 6, the shutter blade 4. This prevents the diaphragm blades from being affected by friction when rotating. In this state, the shutter blade 4 completely covers the opening 3 a of the base plate 3, and the diaphragm blade 6 remains inserted into the opening 3 a of the base plate 3. That is, the opening 5a of the intermediate sheet 5 (not shown) having a slightly smaller diameter than the opening 3a of the base plate 3 is also completely shielded from light. Further, the diaphragm blade 6 may rotate counterclockwise in the figure due to vibration or impact, but the shutter blade 4 is positioned in a state where the opening 5a of the intermediate sheet 5 (not shown) is completely shielded from light. Therefore, there is no adverse effect. Even when the power to the stepping motor 1 is turned off, this state is maintained.

  FIG. 11 is a block diagram of the light quantity control device of this embodiment, FIG. 12 is a flowchart showing the operation of the light quantity control device, FIG. 13 is a time chart showing the operation timing of the light quantity control device, and FIG. a) shows the case where the subject luminance is smaller than a predetermined value, and (b) shows the case where the subject luminance is larger than the predetermined value. Next, the operation of the light quantity control device of this embodiment will be described in detail using these drawings.

  In FIG. 11, 16 is a photographing lens, 17 is an image sensor such as a CCD or CMOS, 18 is an image signal processing circuit for processing an image signal output from the image sensor 17, 19 is a power switch, 20 is a shutter release switch, 21 Is an electronic shutter control circuit that controls charge accumulation and charge discharge of the image sensor 17, 22 is a motor drive circuit that supplies a drive signal to the stepping motor 1 to drive the shutter blade 4 and the diaphragm blade 6, and 23 is an image signal processor. The control circuit controls the circuit 18, the electronic shutter control circuit 21, and the motor drive circuit 22.

  First, in the initial state, the drive lever 2, the shutter blade 4 and the diaphragm blade 6 are in the state shown in FIG. That is, the opening 5 a of the intermediate sheet 5 that is the opening for exposure is completely shielded by the shutter blades 4.

  When the power switch 19 is turned on, the program starts (step S1), the control circuit 23 controls the electronic shutter control circuit 21 to start the operation of the image sensor 17 (step S2), and controls the motor drive circuit 22. The first coil 9 of the stepping motor 1 is positively energized, and the second coil 10 is also positively energized (step S3). As a result, the magnet 12 and the drive lever 2 are rotated to the position shown in FIG. 3, and the shutter blade 4 and the aperture blade 6 are in the state shown in FIG. 6 retracted from the opening 5a of the intermediate sheet 5 serving as an opening for exposure. Even if the first coil 9 and the second coil 10 are de-energized in this state, this state position is maintained by the cogging torque of the stepping motor 1.

  Since the opening 5a, which is an opening for exposure, is in an open state, the image sensor 17 is exposed to subject light, and the output of the image sensor 17 is sent to the control circuit 23. The control circuit 23 measures the subject brightness based on the output of the image sensor 17 (step S4), calculates an appropriate shutter time (Tv value) and aperture value (Av value) (step S5), and the shutter release switch 20 is turned on. It is waited for (step S7).

  When the release switch 20 is turned on, it is determined whether or not the subject brightness measured in step S4 is greater than a predetermined value α (step S8). When the subject luminance is larger than the predetermined value α, the control circuit 23 controls the motor drive circuit 22 to reversely energize the first coil 9 of the stepping motor 1 and to positively energize the second coil 10, and then continue to the first. The coil 9 is reversely energized, and the second coil 10 is reversely energized (step S9). That is, the stepping motor 1 is driven by two pulses. Thereby, the magnet 12 and the drive lever 2 rotate from the position of FIG. 3 to the position of FIG. 5 through the position of FIG. 4, and the shutter blade 4 is retracted from the opening 5a of the intermediate sheet 5 which is an opening for exposure. The diaphragm blade 6 is in the state shown in FIG. 8 inserted on the opening 5a. Even if the first coil 9 and the second coil 10 are de-energized in this state, this state position is maintained by the cogging torque of the stepping motor 1. In this state, the opening for exposure is determined by the opening 6 a of the diaphragm blade 6. That is, the amount of light exposed to the image sensor 17 is reduced to a predetermined amount.

  If the subject brightness is smaller than the predetermined value α, the stepping motor 1 is not driven, and the process immediately proceeds to step S10. That is, the opening for exposure is determined by the opening 5 a of the intermediate sheet 5.

  Next, the control circuit 23 controls the electronic shutter control circuit 21 to release the accumulated charge of the image sensor 17 (step S10). Then, charge accumulation is started again from the time when the discharge operation of the image sensor 17 is completed. Therefore, this timing is the start timing for the effective exposure time. Since the appropriate shutter time is calculated in step S5, the control circuit 23 waits until the shutter time calculated in step S5 elapses after discharging the charge of the image sensor 17 in step S10 (step S11). ). When an appropriate shutter time has elapsed, the control circuit 23 controls the motor drive circuit 22 to reversely energize the first coil 9 of the stepping motor 1 and to positively energize the second coil 10 (step S12). Thereby, the magnet 12 and the drive lever 2 rotate to the position of FIG. Here, when the subject brightness is lower than the predetermined value α, the state shown in FIG. 6 is changed to the state shown in FIG. 7, and when the subject brightness is higher than the predetermined value α, the state shown in FIG. The blade 4 is inserted on the opening 5a of the intermediate sheet 5 or the opening 6a of the diaphragm blade 6 which is the opening for exposure, and completely shields the opening for exposure. Even if the first coil 9 and the second coil 10 are de-energized in this state, this state position is maintained by the cogging torque of the stepping motor 1. The exposure time is from the point in time when the image pickup device 17 completes the discharge of charge and starts re-accumulation until the shutter blade 4 completely blocks the exposure opening.

  When the shutter blade 4 completely blocks the exposure opening in this way, the control circuit 23 controls the image signal processing circuit 18 to capture the output of the image sensor 17 (step S13), and the image signal processing circuit 18 receives the image signal. Writing to a storage device such as a memory card completes one shooting operation.

  As described above, when one photographing operation is completed, the process returns to step S3 again, the shutter blade 4 and the aperture blade are set in the state shown in FIG. 6, and the steps after step S4 are repeated.

  In step S4, it is detected whether the power switch 19 is turned off while waiting for the shutter release switch 20 to be turned on (step S6). If the power switch 19 is turned off, the control circuit 23 drives the motor. The circuit 22 is controlled to reversely energize the first coil 9 and to positively energize the second coil 10 of the stepping motor 1 (step S14). Thereby, the magnet 12 and the drive lever 2 rotate to the position of FIG. Accordingly, the shutter blade 4 and the diaphragm blade 6 are in the state shown in FIG. 7, and the shutter blade 4 is inserted over the opening 5a of the intermediate sheet 5 that is the exposure opening, and completely shields the exposure opening. Even if the first coil 9 and the second coil 10 are de-energized in this state, this state position is maintained by the cogging torque of the stepping motor 1. Thus, all the operations are finished (step S15).

  As described above, in the embodiment of the present invention, the stepping motor 1 which is a single drive source, the shutter blade 4 and the diaphragm blade 6 are respectively inserted into the exposure aperture and retracted from the exposure aperture. Can be selectively driven.

  Further, since the shutter blade 4 and the diaphragm blade 6 can be positioned without using a biasing member such as a spring, the necessary torque of the stepping motor 1 may be a torque that only moves the shutter blade 4 and the diaphragm blade 6. For this reason, the stepping motor 1 can be significantly downsized.

  In addition to the shutter blade 4 and the diaphragm blade 6, the driving member is only the stepping motor 1 and the driving lever 2 fixed to the stepping motor 1, which is compared with those proposed in Patent Documents 1 to 4 above. In addition, the simple structure requires fewer components and the cost can be reduced.

  Further, since the diaphragm blade 6 does not move during the closing operation of the shutter blade 4, only the load of the shutter blade 4 is applied to the stepping motor 1, and the shutter closing time can be increased.

  In addition, even if the shutter blade 4 and the diaphragm blade 6 are de-energized to the stepping motor 1 at the respective positions, the positions thereof are held by the cogging force of the stepping motor 1, so that it is possible to reduce power consumption. .

  Next, the correspondence between the present invention and the embodiment will be described.

  In the above embodiment, the intermediate sheet 5 in FIGS. 1 and 11 corresponds to the light quantity regulating member of the present invention, and the shutter blade 4 in FIGS. 1, 6 to 11 and 13 is the first blade or the present invention. The diaphragm blades 6 in FIGS. 1, 6 to 11 and 13 correspond to the second blades or the light quantity adjusting blades of the present invention, and correspond to the shutter blades in FIGS. The stepping motor 1 and the drive lever 2 shown in FIGS. 1 and 3 to 10 correspond to the drive means of the present invention. 3 corresponds to the first position of the driving means, FIG. 4 corresponds to the second position of the driving means, and FIG. 5 corresponds to the third position of the driving means.

  The above is the correspondence between each configuration of the embodiment and each configuration of the present invention. However, the present invention is not limited to these embodiments, and the functions shown in the claims or the functions of the embodiments It goes without saying that any configuration can be used as long as it can be achieved.

  The aperture blade 6 is provided with an opening 6a having a diameter smaller than that of the opening 5a of the intermediate sheet 5 that determines the opening for exposure. An ND that transmits a predetermined amount of light passing through the opening 6a. A filter may be attached. In this case, the amount of light that reaches the image sensor 17 is a reduced amount of light that is a combination of the dimming due to the ratio of the diameter with the opening 6a and the transmittance of the ND filter, as compared with the case of the opening 5a. Therefore, it is possible to prevent image deterioration due to small aperture diffraction that occurs when the diameter of the opening 6a is too small.

It is a disassembled perspective view of the light quantity control apparatus which concerns on one Embodiment of this invention. It is a disassembled perspective view of the motor which is a component of the light quantity control apparatus of FIG. It is a top view which shows the phase relationship of the magnet of the motor of FIG. 2, a stator, and a drive lever. FIG. 4 is a top view showing a state where the coil energization is switched from the state of FIG. 3 and the magnet is rotated 30 degrees clockwise. FIG. 5 is a top view showing a state where the coil energization is switched from the state of FIG. 4 and the magnet is rotated 30 degrees clockwise. It is a top view which shows the state of a shutter blade | wing and an aperture blade when a motor is in the state of FIG. FIG. 5 is a top view showing a state of shutter blades and aperture blades when the motor is switched from the state of FIG. 3 to the state of FIG. 4. FIG. 6 is a top view showing a state of shutter blades and diaphragm blades when the motor is in the state of FIG. 5. FIG. 6 is a top view showing a state of shutter blades and aperture blades when the motor is switched from the state of FIG. 5 to the state of FIG. 4. It is a table | surface which shows the relationship between motor energization, a shutter blade | wing, and an aperture blade. It is a block diagram of the light quantity control apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the light quantity control apparatus which concerns on one Embodiment of this invention. 4 is a time chart showing the operation timing of the light amount control apparatus according to the embodiment of the present invention, where (a) shows a case where the subject luminance is smaller than a predetermined value, and (b) shows a case where the subject luminance is larger than the predetermined value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 2 Drive lever 3 Ground plate 4 Shutter blade 5 Intermediate sheet 6 Diaphragm blade 7 Blade presser

Claims (5)

A light amount regulating member having an exposure opening;
A first blade capable of rotating between an insertion position of the light quantity regulating member into the exposure opening and a retracted position;
A second blade capable of rotating between an insertion position of the light amount regulating member into the exposure opening and a retracted position;
Driving means for driving the first blade and the second blade by switching to a first position, a second position, and a third position;
At the first position of the driving means, the first blade is driven to the retracted position and the second blade is driven to the retracted position, and at the third position of the driving means, the first blade is retracted to the retracted position, The second blade is driven to the insertion position, and when the driving means moves from the first position to the second position, the first blade is driven to the insertion position, and the second blade is driven to the retracted position, and the drive The light quantity control device according to claim 1, wherein when the means is moved from the third position to the second position, the first blade is driven to the insertion position and the second blade is driven to the insertion position. A light amount regulating member having an exposure opening;
A shutter blade rotatable between an insertion position for shielding the exposure opening of the light amount regulating member and a retreat position for retreating from the exposure opening;
A light amount adjusting blade capable of rotating between an insertion position for adjusting the light amount passing through the exposure opening of the light amount regulating member to a predetermined amount and a retreat position for retracting from the exposure opening;
Drive means for driving the shutter blade and the light amount adjustment blade by switching to a first position, a second position, and a third position;
In the first position of the driving means, the shutter blade is driven to the retracted position and the light amount adjusting blade is driven to the retracted position. In the third position of the driving means, the shutter blade is retracted, and the light amount adjusting blade is the insertion position. When the driving means moves from the first position to the second position, the shutter blade is driven to the insertion position, the light amount adjustment blade is driven to the retracted position, and the driving means is moved from the third position to the second position. The light quantity control device according to claim 1, wherein the shutter blade is driven to the insertion position and the light quantity adjustment blade is driven to the insertion position.   The light quantity control device according to claim 2, wherein there are two retracted positions of the shutter blades.   The light quantity control device according to claim 2, wherein the light quantity adjusting blade is interlocked with the driving unit with a predetermined allowance.   The light amount control device according to claim 2, wherein the driving unit includes a stepping motor and a driving lever.

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