JP2007155774A - Focal plane shutter for digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focal plane shutter for a digital camera constituted so that an aperture part for a photographing optical path is covered with both of a front blade and a rear blade in a stage where imaging information is transferred from a solid-state imaging element to a storage device, and capable of surely obtaining a high-quality image. <P>SOLUTION: When finishing exposure operation, setting operation is started immediately, and a driving member for a front blade 2 and a second driving member for a rear blade 5 are rotated by a setting member 8. Therefore, the front blade performs the setting operation immediately but the rear blade does not start the operation immediately, because a first driving member for a rear blade 4 is restrained by a restraining member 7. As soon as the imaging information is transferred from the solid-state imaging element to the storage device in the stage where the aperture part 1a is covered with four blades 11 to 14 of the front blade and four blades 17 to 20 of the rear blade thereafter, the restraint of the first driving member for the rear blade 4 is released, and the rear blade is actuated. Then, the setting operation is finished. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a digital camera in which a leading blade and a trailing blade are sequentially operated in the same direction at the time of photographing, and an imaging surface is exposed by a slit formed between the two.

  As described in Patent Document 1 below, among the focal plane shutters employed in digital cameras, there are two front blades and rear blades, similar to the focal plane shutters employed in silver halide cameras. Some are provided with one shutter blade and others are provided with only one shutter blade. In general, the shutter blade is composed of two arms each having one end pivotally attached to the main plate and a plurality of blades pivotally supported in turn toward the other end. In addition, both those equipped with two shutter blades and those equipped with only one are said to operate the shutter blades with an operation method called normally open method and normally closed method. There are cases where it is operated in an operating manner. The present invention relates to a focal plane shutter for a digital camera that includes two of the shutter blades and operates them in a normally closed manner.

  In the case of such a focal plane shutter, the two shutter blades are operated as follows. In the photographing standby state, the plurality of blades of the leading blade cover the opening for the photographing optical path, and the plurality of blades of the trailing blade are stored outside the opening. When shooting, when the release button of the camera is pressed, usually, the charge accumulated in the solid-state image sensor is released first. This is because there is a possibility of light leakage from between the blades and the like due to leaving for a long time even though the leading blade has previously covered the opening for the photographing optical path. Then, the leading blade and the trailing blade are exposed and traveled sequentially in the same direction, and the solid-state imaging device is exposed by the slit formed by both. After that, when the plurality of blades of the front blade are stored outside the opening for the photographing optical path and the plurality of blades of the rear blade cover and stop the opening, the imaging information is transferred from the solid-state imaging device to the storage device. Is done. When the transfer ends, the leading blade and the trailing blade are returned to the photographing standby state. Therefore, in the case of a camera equipped with this type of focal plane shutter, it is necessary to provide an optical viewfinder.

JP 2004-61865 A

  In general, digital cameras with built-in focal plane shutters are relatively high-end models. Among them, those with built-in focal plane shutters that have two shutter blades are high-grade, multifunctional, and high-performance. It is characterized in that a high-quality image can be obtained. By the way, in the focal plane shutter having two shutter blades, as described above, the exposure traveling of the leading blade and the trailing blade is finished, and the opening for the photographing optical path is covered with a plurality of blades of the trailing blade. In this state, the imaging information is transferred from the solid-state imaging device to the storage device. At the time of the transfer, it is known that when light strikes the solid-state image sensor, a smear phenomenon occurs and a high-quality image cannot be obtained. However, as is well known, although the opening for the photographing optical path is covered by a plurality of blades of the rear blade, even under extremely small light, even between the blades, etc. It is extremely difficult to prevent leakage. For this reason, in high-grade models, there is also a sense of safety, and at the stage of transfer to the storage device, the opening for the imaging optical path is not only covered by the multiple blades of the rear blade, but also It is expected that some measures will be taken.

  The present invention has been made to solve such problems, and the object of the present invention is to provide a focal plane shutter having two shutter blades, a front blade and a rear blade, after the exposure operation, At the stage where the imaging information is transferred from the solid-state imaging device to the storage device, the opening for the photographing optical path is double-covered by both the front blades and the rear blades. Another object of the present invention is to provide a focal plane shutter for a digital camera that can reliably obtain a high-quality image.

  In order to achieve the above object, the focal plane shutter for a digital still camera according to the present invention has a pushing portion and is connected to the leading blade, and is operated by the biasing force of the leading blade driving spring during exposure operation. A leading blade driving member that causes the leading blade to open, a trailing blade first driving member having a restrained portion and connected to the trailing blade, and a trailing blade driving spring during exposure operation. A second driving member for the rear blade that operates with the first driving member for the rear blade by the urging force and causes the rear blade to close, and an attachment for operating the first driving member for the rear blade to the exposure operation start position. The set spring having power, and the leading blade driving member and the trailing blade second driving member are operated against the biasing force of each of the driving springs by operating from the initial position during the setting operation. Exposure operation during release It has a set member that returns to the initial position in advance, a restraining portion and a driven portion, and when the set member is set, the restraining portion engages with the restrained portion from the initial stage. The first driving member is prevented from being moved to the exposure operation start position by the urging force of the set spring, and the driven portion is pushed by the pushing portion at the final stage of the setting operation, thereby causing the rear blade first And a deterring member that unblocks the driving member.

  The present invention provides a focal plane shutter for a digital camera having two shutter blades, a front blade and a rear blade. After exposure running, only the front blade is immediately set and operated, The imaging information is transferred from the solid-state imaging device to the storage device at the stage where the imaging light path opening is covered almost double with the plurality of blades of the rear blade, immediately before the end of the setting operation of the leading blade immediately after that, Since the trailing blade is set by the leading blade driving member, the imaging information can be suitably transferred from the solid-state imaging device to the storage device, and a high-quality image can be reliably obtained. Is.

  Embodiments of the present invention will be described with reference to the illustrated examples. 1 to 4 are diagrams for explaining the embodiment. FIG. 1 is a plan view showing a set state (photographing standby state), and FIG. 2 shows an end state of the exposure operation. FIG. 3 is a plan view showing a state immediately before the end of the set operation performed immediately after the state of FIG. FIG. 4 is a timing chart for explaining the operation of the embodiment.

  First, the configuration of the present embodiment will be described mainly with reference to FIG. In FIG. 1, the shutter base plate 1 is formed with an opening 1 a having a rectangular shape that is horizontally long. Although not shown because it is well known, an intermediate plate and an auxiliary ground plate are sequentially attached to the back side of the shutter base plate 1 with a predetermined interval between the shutter base plate 1 and the intermediate plate. A vane chamber for a leading blade described later is formed, and a blade chamber for a trailing blade described later is formed between the intermediate plate and the auxiliary ground plate. In the intermediate plate and the auxiliary ground plate, an opening similar to the opening 1a is formed, but in this embodiment, the opening 1a regulates the opening for the photographing optical path. Further, two arc-shaped long holes 1b, 1c and a small rectangular hole 1d are formed on the right side of the opening 1a, and the planar shape is substantially C-shaped at the lower end of the long holes 1b, 1c. Although a well-known buffer member is attached, the illustration thereof is omitted for easy understanding of the drawing.

  Shafts 1e, 1f, and 1g are erected on the front surface side of the shutter base plate 1, and shafts 1h, 1i, 1j, and 1k are erected on the back side. Of these, shafts 1e and 1h , And the shaft 1f and the shaft 1i are arranged concentrically. Further, a support plate and a printed wiring board (not shown) are attached to the front ends of the shafts 1e, 1f, and 1g that are erected on the surface side, and are arranged on the shutter base plate 1 side of them. A front blade electromagnet and a rear blade electromagnet are attached to the support plate, but the mounting structure thereof conforms to a well-known structure described in Japanese Patent Application Laid-Open No. 2001-21194, etc., and is not shown. It is.

  A synthetic resin front blade drive member 2 is rotatably attached to the shaft 1e provided upright on the surface of the shutter base plate 1, and is counterclockwise by a front blade drive spring (not shown). It is biased to rotate in the direction. The leading blade driving member 2 includes a roller 2a, a driving pin 2b, a mounting portion 2c, and a pushing portion 2d. Among them, the drive pin 2b is provided on the back side, and its root portion comes into contact with the above-described buffer member (not shown) attached to the long hole 1b at the end of the exposure operation. The tip portion passes through the long hole 1b. Further, as described in the above-mentioned Japanese Patent Application Laid-Open No. 2001-211942, a well-known iron piece member 3 is attached to the inside of the attachment portion 2c with a spring (not shown) interposed therebetween. When a leading blade electromagnet (not shown) is energized, it can be attracted to the iron core.

  The above-mentioned shaft 1f erected on the surface side of the shutter base plate 1 allows the rear blade first drive member 4 and the rear blade second drive member 5 to rotate individually from the shutter base plate 1 side. The rear blade second drive member 5 is attached and urged to rotate counterclockwise by a well-known rear blade drive spring (not shown). The first rear blade drive member 4 is made of synthetic resin and includes a restrained portion 4a, a drive pin 4b, and a pushed portion 4c. The drive pin 4b is provided on the back side, and its root portion comes into contact with the above-described buffer member (not shown) attached to the long hole 1c at the end of the exposure operation. The part penetrates the long hole 1 c and protrudes to the back side of the shutter base plate 1.

  On the other hand, the second driving member 5 for the rear blades is also made of synthetic resin, and each of the driven portions 5a, the pressing portion 5b, and the mounting portion are formed thick on the first driving member 4 side for the rear blades. 5c. Among them, the pushing portion 5b is formed to extend longer toward the shutter base plate 1 than the pushed portion 5a, and the end face of the above-described pushed portion 4c formed on the first driving member 4 for the rear blade. Can come in contact with. Further, the attachment portion 5c is formed so as to protrude greatly toward the subject side, and the iron piece member 6 is attached to the inside thereof with a spring (not shown) interposed in the same manner as the iron piece member 3 described above. When the above-mentioned electromagnet for the rear blade (not shown) is energized, it can be attracted to the iron core. Further, in the present embodiment, a set spring having a biasing force weaker than that of the rear blade drive spring is hung between the first drive member 4 for the rear blade and the second drive member 5 for the rear blade. The first blade driving member 4 is urged to rotate clockwise and the rear blade second driving member 5 is urged to rotate counterclockwise. The set spring is described later. As can be understood from the operation description, it is originally intended to rotate the rear blade first drive member 4 in the clockwise direction, so that it is hung between the rear blade first drive member 4 and the shutter base plate 1. However, there is no problem.

  From the shutter base plate 1 side, the restraining member 7 and the set member 8 are individually attached to the shaft 1g standing on the surface side of the shutter base plate 1 so as to be rotatable. Among them, the restraining member 7 has two bent portions bent to the set member 8 side and one bent portion bent to the shutter base plate 1 side. Among them, the two bent portions bent toward the set member 8 are the restraining portion 7a and the driven portion 7b, but the bent portion bent toward the shutter base plate 1 is the stopper portion 7c, which is described above. The shutter base plate 1 is inserted into a square hole 1d. In the present embodiment, a spring is hung between the restraining member 7 and the set member 8, and the restraining member 7 is urged to rotate counterclockwise so that the set member 8 is rotated clockwise. It is energized to rotate.

  On the other hand, the set member 8 is made of a synthetic resin and has pushing portions 8a and 8b and a pushed portion 8c. As described above, the set member 8 is urged to rotate clockwise by a spring (not shown) that is hung between the set member 8 and the restraining member 7, but in FIG. Is prevented by a member on the camera body (not shown) suppressing the pushed portion 8c. When the deterrence is released, it is rotated clockwise and stopped by a stopper (not shown) provided on the shutter base plate 1, but the stop position is the initial position for the set member 8. It is. In this embodiment, the restraining member 7 is urged to rotate counterclockwise and the set member 8 is urged to rotate clockwise by a single spring (not shown). The restraining member 7 and the set member 8 may be urged as such by separate springs.

  Finally, the configuration of the leading and trailing blades disposed on the back side of the shutter base plate 1 will be described. First, the leading blade is provided with two arms 9 and 10 that are rotatably attached to the shaft 1h and the shaft 1j, and four blades 11 that are pivotally supported by both of them toward the tip thereof. , 12, 13, 14 and the blade 14 pivotally supported at the forefront is a slit forming blade. As is well known, the drive pin 2 b of the leading blade drive member 2 is fitted in a hole formed in the arm 9. On the other hand, the rear blade has two arms 15 and 16 rotatably attached to the shaft 1i and the shaft 1k, and four blades 17, 18, 19, The blade 20 that is composed of 20 and is pivotally supported at the forefront is a slit forming blade. And the drive pin 4b of the 1st drive member 4 for rear blades is fitted by the hole formed in the arm 15. FIG.

  Next, the operation of the present embodiment will be described with reference to FIGS. 1 to 4. The image frame described in FIG. 4 means the distance between the upper side and the lower side of the opening 1a in FIG. In the present embodiment, among the parallel lines regulating the image frame, the lower line indicates the upper side position of the opening 1a, and the upper line indicates the lower side position. FIG. 1 shows a shutter set state, that is, a camera standby state. At this time, the set member 8 is prevented from being pushed by the camera body side member (not shown), so that the set member 8 rotates clockwise by a biasing force of a spring (not shown) to return to the initial position. This set position is maintained.

  The leading blade driving member 2 and the trailing blade second driving member 5 are configured to rotate counterclockwise by the biasing force of each driving spring (not shown). 5a is restrained by the pushing portions 8a and 8b of the set member 8, and this state is maintained. For this reason, the restraining member 7 is pushed slightly by the pushed portion 7b by the pushing portion 2d of the leading blade drive member 2 and slightly rotated clockwise against the biasing force of a spring (not shown). The stopper portion 7 c is separated from the edge of the hole 1 d of the shutter base plate 1. Further, the first driving member 4 for the rear blade is rotated in the clockwise direction by a biasing force of a set spring (not shown), and the pushed portion 4c is pushed by the second driving member 5 for the rear blade. 5b is contacted.

  The leading blade arm 9 and trailing blade arm 15 are rotated clockwise by the driving pin 2b of the leading blade driving member 2 and the driving pin 4b of the trailing blade first driving member 4. The four blades 11 to 14 of the leading blade are in an unfolded state and cover the opening 1a, and the four blades 17 to 20 of the trailing blade are in a superimposed state and are positioned above the opening 1a. Is stored. Therefore, in the case of the camera having the focal plane shutter according to the present embodiment, the photographer observes the subject image before photographing using the optical viewfinder.

  When the release button of the camera is pressed during shooting, first, the leading blade electromagnet and the trailing blade electromagnet (not shown) are energized and attached to the leading blade driving member 2 and the trailing blade second driving member 5. Each iron piece member 3 and 6 is adsorbed and held. Next, the camera body side member (not shown) releases the restraint of the set member 8 against the driven portion 8c, so that the set member 8 is rotated clockwise by the urging force of the spring (not shown). Return to position. Further, as the set member 8 is rotated in the clockwise direction, the pushing portions 8a and 8b of the set member 8 are separated from the roller 2a and the pushed portion 5a, so that each of the driving members 2 and 4 is well known. , 5 are rotated counterclockwise, albeit very slightly. However, since the iron pieces 3 and 6 are attracted and held by the respective electromagnets, they are not substantially rotated, and the four blades 11 to 14 of the leading blade remain covering the opening 1a. The rear blades 17 to 20 maintain the retracted state. In this state, the charge accumulated in the solid-state image sensor is released.

  Thereafter, the current supply to the leading blade electromagnet is first cut off, and the power supply to the trailing blade electromagnet is cut off after a predetermined time. Therefore, first, when the attraction force of the leading blade electromagnet is lost, the leading blade driving member 2 is rapidly rotated counterclockwise by the biasing force of the leading blade driving spring (not shown). Then, the rotation of the restraining member 7 is released by the pushing portion 2d against the pushed portion 7b, and therefore, the restraining member 7 is rotated counterclockwise by the biasing force of a spring (not shown). It stops by contacting the edge of the hole 1d of the shutter base plate 1. On the other hand, when the leading blade drive member 2 rotates counterclockwise, the drive pin 2b rotates the arm 9 counterclockwise. Therefore, the four blades 11 to 14 of the leading blade travel downward while increasing the mutual overlap, and the opening 1 a is opened by the upper edge of the slit forming blade 14.

  On the other hand, the energization to the electromagnet for the trailing blade is cut off after a predetermined time since the energization to the electromagnet for the leading blade is cut off as described above, so that the attraction force to the iron piece member 6 is lost, and the second driving member for the trailing blade 5 is rapidly rotated counterclockwise by the urging force of a trailing blade drive spring (not shown). At that time, since the pushing portion 5b of the second driving member 5 for the rear blade pushes the driven portion 4c of the first driving member 4 for the rear blade, the first driving member 4 for the rear blade is also rotated counterclockwise. It is done. As a result, the drive pin 4b of the first drive member 4 for the rear blades rotates the arm 15 in the counterclockwise direction, so that the four blades 17 to 20 of the rear blade travel downward while reducing mutual overlap. The opening 1 a is covered with the lower edge of the slit forming blade 20.

  In this way, the leading blade and the trailing blade continuously expose the imaging surface of the imaging device by the slits formed by the slit forming blades 14 and 20, but the final stage of the exposure operation Then, first, the driving pin 2b of the leading blade driving member 2 comes into contact with a buffer member (not shown) attached to the lower end edge of the long hole 1b of the shutter base plate 1 to stop the exposure traveling of the leading blade. It is done. Thereafter, the restrained portion 4a of the first driving member 4 for the rear blade pushes the restraining portion 7a of the restraining member 7 and temporarily rotates the restraining member 7 clockwise against the biasing force of a spring (not shown). Immediately thereafter, the drive pin 4b of the first drive member 4 for the rear blade comes into contact with a buffer member (not shown) attached to the lower end edge of the long hole 1c of the shutter base plate 1, thereby Exposure running is stopped.

  FIG. 2 shows the state in which the exposure operation is completed in this way. At this time, the set member 8 is in the initial position, and the four blades 11 to 14 of the leading blade are superimposed. The four blades 17 to 20 of the rear blade are deployed to cover the opening 1a. Further, the restraining member 7 has its stoppered portion 7 c in contact with the edge of the hole 1 d of the shutter base plate 1. Normally, when this state is reached, the imaging information is immediately transferred from the solid-state imaging device to the storage device. However, in this embodiment, the setting operation is started immediately without being transferred at this stage.

  In the setting operation of this embodiment, a member on the camera main body (not shown) pushes the driven portion 8c of the setting member 8, and the setting member 8 is counterclockwise against a biasing force of a spring (not shown). This is done by rotating. By the rotation, the set member 8 is first pushed while rotating the roller 2a by the pressing portion 8a, and the leading blade driving member 2 is rotated clockwise against the biasing force of the leading blade driving spring (not shown). Rotate to Therefore, the driving member 2 for the leading blade operates the four blades 11 to 14 of the leading blade upward while reducing the mutual overlap by rotating the arm 9 clockwise by the driving pin 2b. I will let you.

  Immediately after starting to rotate the leading blade driving member 2 in the clockwise direction, the pushing portion 8b of the setting member 8 pushes the pushed portion 5a of the second driving member 5 for the trailing blade, thereby The blade second drive member 5 starts to rotate clockwise against the urging force of a rear blade drive spring (not shown). Therefore, the rear blade first drive member 4 also tries to rotate in the clockwise direction following the rotation of the rear blade second drive member 5 by the biasing force of a set spring (not shown). The inhibited portion 4a is immediately stopped by being inhibited by the inhibiting portion 7a of the inhibiting member 7. Therefore, although the rear blade is operated slightly, only the second drive member 5 for the rear blade is rotated clockwise while the four blades 17 to 20 cover the opening 1a.

  In this way, only the four blades 11 to 14 of the leading blade cover the opening 1a by reducing mutual overlap, so that the opening 1a extends from the bottom to the top of the leading blade 4. The two blades 11 to 14 and the four blades 17 to 20 of the rear blades are covered twice. In the case of the present embodiment, as shown in FIG. 3, when the four blades 11 to 14 of the leading blade completely cover the opening 1a, the imaging information is transferred from the solid-state imaging device to the storage device. Is done. Therefore, at this time, since the opening 1a is completely double-covered by the four blades 11-14 of the leading blade and the four blades 17-20 of the trailing blade, the four blades of the leading blade As compared with the case where only 11 to 14 is covered, it is possible to almost completely eliminate the occurrence of the smear phenomenon.

  Immediately after the rotation of the set member 8, the iron piece members 3 and 6 attached to the leading blade driving member 2 and the trailing blade second driving member 5 are not shown, and the leading blade electromagnet and the trailing blade are not shown. While being in contact with the iron core of the electromagnet, the pushing portion 2d of the leading blade drive member 2 pushes the pushed portion 7b of the restraining member 7 to rotate the restraining member 7 counterclockwise, and the restraining portion 7a is restrained. Stop when the deterrence of part 4a is solved. The stop position is the set position of the set member 8 shown in FIG. Further, as described above, when the inhibition of the restrained portion 4a is released, the rear blade first drive member 4 is rotated clockwise by the biasing force of a set spring (not shown), and the driven portion 4c is stopped by contacting the pushing portion 5b of the second driving member 5 for the rear blade. Then, the drive pin 4b rotates the arm 15 clockwise by the clockwise rotation of the first blade driving member 4 thereafter, so that the four blades 17 to 20 of the rear blade increase the mutual overlap. It is actuated upward and stored in a position above the opening 1a. As a result, all the structural members have returned to the photographing standby state shown in FIG.

  In the above description, it is assumed that the imaging information is transferred from the solid-state imaging device to the storage device when the four blades 11 to 14 of the leading blade completely cover the opening 1a during the setting operation. However, the present invention is not limited to such a case, and the imaging information is transferred from the solid-state imaging device to the storage device immediately before the four blades 11 to 14 of the leading blade completely cover the opening 1a. However, substantially the same effect can be achieved.

  As is well known, in the focal plane shutter, in the state immediately before the start of the exposure operation, each drive member having the iron piece member is directly held by the attractive force of the respective electromagnets, and at the start of the exposure operation, By what is called a direct type configured only to release its magnetic holding force, and by means of a member that is mechanically held by each locking member and actuated by an electromagnet. A lock type configured to release the holding of the lock member is known. Although the above embodiments have been described with respect to the direct type shutter among them, the present invention can also be applied to a locking type. In the above embodiment, each of the leading blade and the trailing blade has four blades. However, the present invention is not limited to such a number. It does not matter if the number of sheets is different.

It is the top view of the Example which showed the set state (shooting standby state). It is a top view of the Example which showed the exposure operation completion state. FIG. 3 is a plan view showing a state immediately before the end of the set operation performed immediately after the state of FIG. 2. It is a timing chart for demonstrating the action | operation of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a Opening part 1b, 1c Long hole 1d Hole 1e, 1f, 1g, 1h, 1i, 1j, 1k Axis 2 Lead blade drive member 2a Roller 2b, 4b Drive pin 2c, 5c Mounting part 2d, 5b, 8a , 8b Pushing part 3, 6 Iron piece member 4 Rear blade first drive member 4a Suppressed part 4c, 5a, 7b, 8c Pushed part 5 Rear blade second drive member 7 Suppression member 7a Suppressing part 7c Stopper Part 8 Set member 9, 10, 15, 16 Arm 11, 12, 13, 14, 17, 18, 19, 20 Blade

Claims (1)

  It has a pushing part and is connected to the leading blade, and it has a leading blade driving member that is actuated by the biasing force of the leading blade driving spring during the exposure operation and opens the leading blade, and a restrained portion. And the first driving member for the rear blade connected to the rear blade and the biasing force of the driving spring for the rear blade at the time of the exposure operation, the first driving member for the rear blade is operated to close the rear blade. A second driving member for the rear blade to be performed, a set spring having an urging force for operating the first driving member for the rear blade to the exposure operation start position, and a leading blade that operates from the initial position during the setting operation. A set member that operates the drive member for the rear blade and the second drive member for the rear blade against the urging force of each of the drive springs to return to the initial position prior to the exposure operation when the camera is released; And having the pushing part When the material is set, the restraining portion engages with the restrained portion from the initial stage, and the biasing force of the set spring restrains the first drive member from moving to the exposure operation start position. And a depressing member for releasing deterrence of the first driving member for the rear blades by pushing the pushed portion by the pushing portion in the final stage of the focal plane shutter for a digital camera.

Images