JP2010002918A - Lens shutter for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens shutter for a camera suitable for miniaturization, which is configured so that an area facing a photographic lens is made thinner. <P>SOLUTION: A shutter blade 7, a shutter blade 8, a diaphragm member 11 and a light shielding member 12 are arranged in order from a subject side. An aperture part 11b having a smaller diameter than an exposure aperture is formed on the diaphragm member 11. The light shielding member 12 is configured to cover a gap formed between the diaphragm member 11 and the edge of an aperture part 2a. Since the shutter blade 8 and the diaphragm member 11 are composed such that they are always partially superposed and the superposed area continuously changes, they are prevented from engaging each other during operation. Consequently, it is not necessary to partition both of them by a plate member as in the conventional manner, thereby a unit is made thinner and also external size of bottom plates 1 and 2 is made small. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera lens shutter provided with a light amount control means capable of limiting the amount of subject light reaching a film, a CCD, or the like by regulating the aperture of an exposure opening.

  As is well known, camera shutters include a lens shutter disposed in the vicinity of a photographing lens and a focal plane shutter disposed immediately before a film or a CCD. Among them, the lens shutter is configured to open and close a circular exposure opening. Usually, a plurality of shutter blades are opened from the center of the exposure opening and closed toward the center. However, only one shutter blade is provided, and the shutter blade is opened from a predetermined peripheral edge of the exposure opening, and is closed toward the peripheral edge after being fully opened.

  On the other hand, a camera is usually provided with a light amount control mechanism in the vicinity of the taking lens. And what is generally adopted as such a light quantity control mechanism is a so-called diaphragm mechanism, and there are mainly two types of mechanisms. That is, one of them is that a plurality of diaphragm blades are simultaneously rotated in the same direction or simultaneously operated in the opposite direction (including rotation operation), and these blades cooperate with each other about the optical axis. The aperture diameter can be continuously changed. The other is to prepare an aperture member having at least one circular aperture having a diameter smaller than the exposure aperture, or to prepare a plurality of aperture members having only one aperture. The opening can be selectively inserted into the photographing optical path.

  Further, as a light amount control mechanism, there is a mechanism using an ND filter in addition to the above-described diaphragm mechanism. In that case, one ND filter having a predetermined density is made to advance and retreat to the exposure aperture, and a plurality of ND filters having different densities are prepared, and these are selectively advanced to the exposure aperture. There are things that let you do. Further, among those using the ND filter, some of the above-mentioned two types of diaphragm mechanisms are combined with the latter type of diaphragm mechanism. As an example, a circular opening having a smaller diameter than the exposure opening is covered with an ND filter, and the opening covered with the ND filter is advanced and retracted to the exposure opening. Such a light quantity control mechanism is suitable for the case where it is desired not to be affected by diffraction because the light quantity of the subject can be greatly reduced without making the opening portion too small.

  As can be understood from the above description, the lens shutter mechanism and the light amount control mechanism are not disposed at the position immediately before the film or the CCD, but are disposed at a position near the photographing lens. Therefore, in a camera provided with these two mechanisms, it has been usual to manufacture them as one unit. An example of such a configuration is described in Patent Document 1. The present invention thus relates to a camera lens shutter unitized with a light quantity control mechanism.

JP 2001-117135 A

  As is well known, when only the lens shutter mechanism is unitized, the shutter blades are configured to operate in the blade chamber formed between the two plate members. Even when only the light quantity control mechanism is unitized, the diaphragm blades and the like are configured to operate in the blade chamber formed between the two plate members. Therefore, when these two mechanisms are simply unitized, the two chambers are formed by four plate members. However, such a configuration is not preferable for reducing the cost and thickness of the unit (reducing the dimension in the direction along the optical axis). Therefore, as described in the above publication, conventionally, it has been usual to form two chambers by three plate members.

  By the way, this type of unit is used in compact cameras, and most of them are being motorized, but recently, with the rapid growth of digital cameras, the cost of such units has been reduced. And the demand for downsizing is getting bigger. In particular, since this type of unit is disposed in the vicinity of the photographing lens, there is a strong demand for a thin circular area centering on the optical axis adjacent to the photographing lens.

  The present invention has been made to solve such problems, and the object of the present invention is to provide a unit that includes a shutter mechanism and a light amount control mechanism operated by each motor. It is an object of the present invention to provide a camera lens shutter suitable for miniaturization so that at least a region facing a photographing lens is thinned.

  In order to achieve the above object, a camera lens shutter according to the present invention comprises two ground planes that form a blade chamber between them and overlap the openings to form a circular exposure opening. At least one shutter blade disposed in the blade chamber for opening and closing the exposure opening, and attached to one of the base plates outside the blade chamber, and an output portion into the blade chamber A first motor that extends and opens and closes the shutter blades, and a first member that is disposed in the blade chamber and has an opening having a smaller diameter than the exposure opening, serves as a light shield. The shutter blade, which is constituted by the second member and is adjacent to the shutter blade in any operating state, moves forward and backward with respect to the exposure opening so that a part thereof overlaps, and the opening of the first member is exposed to the exposure. The state of entering the opening The light amount control means for covering the gap formed between the first member and the edge of the exposure opening by the second member, and is attached to one of the ground plates outside the blade chamber And an output portion extending into the blade chamber and having a second motor for causing the light amount control means to perform the advance / retreat operation.

  In that case, if the opening of the first member is covered with the sheet of the ND filter, the subject light can be further reduced.

  As described above, according to the present invention, when the shutter mechanism and the light amount control mechanism operated by each motor are unitized, it is possible to eliminate the need for the plate member that separates the two blade chambers as in the prior art. Therefore, it is possible to make the area facing the photographing lens thinner and to arrange them close to each other, which is extremely effective for making the camera compact. In addition, the planar shape of the unit can be reduced in size.

FIG. 3 is a plan view of the initial state of Example 1 as viewed from the subject side. FIG. 2 is a plan view of the blade chamber of the first embodiment when viewed from the subject side, and shows the same initial state as FIG. 1. FIG. 3 is a plan view of the first embodiment viewed in the same manner as in FIG. 2, showing a state in which the aperture of the aperture member is inserted into the exposure aperture from the state of FIG. 2. FIG. 4 is a plan view of the first embodiment viewed in the same manner as in FIGS. 2 and 3 and shows a state in which the shutter blades are closed from the state of FIG. 3. FIG. 5 is a plan view of the first embodiment viewed in the same manner as in FIGS. 2 to 4, and shows a state in which the shutter blades are closed from the state of FIG. 2. It is the top view which showed the initial state of Example 2 similarly to FIG. 2 of 1st Example. FIG. 7 is a plan view of Example 2 viewed in the same manner as in FIG. 6, showing a state in which the aperture of the aperture member is inserted into the exposure aperture from the state of FIG. 6. FIG. 8 is a plan view of the second embodiment viewed in the same manner as in FIGS. 6 and 7 and shows a state where the shutter blades are closed from the state of FIG. 7.

  The embodiment of the present invention will be described with reference to two illustrated examples. In addition, these embodiments have a configuration that can be used for both a camera using a film and a digital camera. However, for convenience of explanation, a case where the present invention is applied to a digital camera will be described. 1 to 5 show the first embodiment, and FIGS. 6 to 8 show the second embodiment, both of which are plan views as viewed from the subject side. In the description, the subject side is referred to as the front side, and the imaging element side is referred to as the back side.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of the present embodiment as viewed from the subject side, and FIGS. 2 to 5 are plan views showing the blade chamber in each operating state. First, the configuration of this embodiment will be described with reference to FIGS. 1 and 2. In this embodiment, a blade chamber is formed between a main ground plate 1 disposed on the subject side and an auxiliary ground plate 2 disposed on the image sensor side. The two ground planes 1 and 2 are both made of synthetic resin and have almost the same outer shape, and the exposure opening (maximum aperture) is formed by the circular openings 1a and 2a formed in the substantially central part thereof. It is regulated. In addition, in FIG. 2, although the main external shape of the main ground plane 1 is shown with the dashed-two dotted line, this is the same also in the case of FIGS.

  Then, next, the structure of the surface side of the main ground plane 1 is demonstrated mainly using FIG. First, three attachment portions 1b, 1c, and 1d used for attachment to the camera are provided so as to surround the opening 1a. Two motors 3 and 4 are attached by hooks 1 e and 1 f formed integrally with the main base plate 1 and screws 5 and 6. These motors 3 and 4 are motors called moving magnet type motors described in JP 2000-60088 A and the like, and since the configuration thereof is well known, a specific description thereof is omitted. The permanent magnet rotor rotates only within a predetermined angle range, and the drive pins 3a and 4a provided at the portions projecting in the radial direction from the rotors extend from the long holes 1g and 1h formed in the main base plate 1. It is inserted into the blade chamber.

  Next, the configuration of the back side of the main ground plate 1 will be described. First, the parts that are shown in FIG. 1 but not shown in FIG. 2 will be described. The main ground plate 1 and the auxiliary ground plate 2 are attached to each other by hooking a hook portion 1i provided on the main ground plate 1 to the edge of the auxiliary ground plate 2 and inserting a screw (not shown) from the back side of the auxiliary ground plate 2. 2 is inserted into the hole 2b (see FIG. 2) and screwed into the mounting portion 1j of the main base plate 1. The mounting portion 1j also serves as a spacer between the main base plate 1 and the auxiliary base plate 2. In addition, the main base plate 1 is provided with dedicated spacers 1k, 1m, 1n, and 1p. Yes.

  Moreover, in FIG. 2, the site | part provided in the back side of the main base plate 1 is shown with the cross section with the above-mentioned drive pins 3a and 4a. Therefore, first, the main ground plate 1 is provided with stoppers 1q, 1r, 1s, and 1t for the respective operation members described later. Further, shafts 1 u, 1 v, 1 w are provided on the back side of the main ground plate 1. Among them, the shutter blade 7 is rotatably attached to the shaft 1u, and the shutter blade 8 is rotatably attached to the shaft 1v. The shutter blades 7 and 8 are arranged so that the shutter blade 7 is on the subject side, and the drive pins 3a are provided in the long holes 7a and 8a formed in the shutter blades 7 and 8 as is well known. It is mated.

  A diaphragm member 9 disposed on the auxiliary base plate 2 side of the shutter blade 8 is rotatably attached to the other shaft 1w. The diaphragm member 9 has a long hole 9a and a circular opening 9b having a diameter smaller than that of the exposure opening (openings 1a and 2a), and the drive pin 4a is fitted in the long hole 9a. is doing. Further, a sheet-like ND filter 10 is attached to the rear side of the diaphragm member 9 and covers the opening 9b. The ND filter 10 operates in a recess 2c formed in the auxiliary base plate 2 so as not to slide on the auxiliary base plate 2 during operation of the throttle member 9.

  Next, the operation of the present embodiment will be described with reference to FIGS. 2 to 5. However, as already described, the operation will be described in the case where it is adopted in a digital camera. FIG. 2 shows an initial state of this embodiment. That is, this digital camera is a normally open type, and when the power is on, the diaphragm member 9 is retracted from the exposure opening, and the shutter blades 7 and 8 are fully open. Therefore, the image sensor is exposed to subject light, and the subject image can be observed on the monitor. At this time, the motors 3 and 4 are not energized. However, with a well-known motor configuration, the rotor of the motor 3 is given a counterclockwise rotating force, and the rotor of the motor 4 rotates clockwise. The power to do is given. Therefore, the shutter blades 7 and 8 are brought into contact with the stoppers 1q and 1t, and the diaphragm member 9 is brought into contact with the stopper 1s.

  When the shutter button is pressed in this state, whether to shoot with or without reducing the light amount of the subject is determined based on the measurement result of the subject light. If it is decided to shoot with the light amount of the subject reduced, the rotor of the motor 4 is rotated counterclockwise and the diaphragm member 9 is rotated clockwise. Then, the diaphragm member 9 slides with respect to the shutter blade 8, and the tip of the diaphragm member 9 comes into contact with the stopper 1r and stops. That is, the diaphragm member 9 always maintains a sliding contact relationship with the shutter blade 8 from the start to the stop thereof. The state stopped in this way is shown in FIG. At this time, the energization of the motor 4 may not be interrupted, but even if it is interrupted, this state is maintained by a known motor configuration. Depending on the specifications of the camera, this state may not be obtained by the release of the camera, but may be automatically obtained according to the subject light.

  In this way, when the state of FIG. 3 is obtained, a shooting start signal is then given to the imaging device. When a predetermined photographing time has elapsed, the motor 3 is energized from the control circuit, and the rotor is rotated clockwise. For this reason, the shutter blades 7 and 8 rotate in opposite directions. At this time, the shutter blade 8 slides with respect to the aperture member 9. And after closing the opening part 9b, it contacts and stops to the stoppers 1t and 1q. In other words, the shutter blade 8 always maintains a sliding contact relationship with the aperture member 9 from the start of operation until it stops. The stop state is shown in FIG.

  Thereafter, when the imaging information is transferred to the storage device in this closed state, the motors 3 and 4 are energized before and after. However, at this time, unlike the above case, since the current is supplied in the reverse direction, both the shutter blades 7 and 8 and the aperture member 9 are rotated in the opposite direction. The sliding contact relationship between the blade 8 and the diaphragm member 9 is maintained from the beginning to the end. The shutter blades 7 and 8 are brought into contact with the stoppers 1q and 1t, and the diaphragm member 9 is brought into contact with the stopper 1s and stopped. Immediately thereafter, the motors 3 and 4 are de-energized to return to the initial state shown in FIG. Return.

  Further, when the subject light is not relatively bright and the image is taken without using the opening 9b as described above, in the state shown in FIG. When a predetermined photographing time has elapsed, the motor 3 is energized from the control circuit, and the rotor is rotated clockwise. Therefore, the shutter blades 7 and 8 rotate in opposite directions. At this time, the shutter blade 8 slides with respect to the aperture member 9. Finally, the shutter blades 7 and 8 are stopped in the state shown in FIG. 5 as already described, but during that time, the sliding contact relationship between the shutter blades 8 and the diaphragm member 9 is maintained throughout. Yes. Accordingly, the shutter blades 7 and 8 are thereafter returned to the state shown in FIG. 2 without needing to be described, but the sliding contact relationship between the shutter blades 8 and the diaphragm member 9 is maintained even at that time. .

  As described above, according to the present embodiment, in any operating state, a part of the shutter blade 8 and a part of the diaphragm member 9 are always kept in contact with each other, and their contact areas are continuously changed. Thus, the shutter blade 8 and the aperture member 9 are not engaged with each other, and the shutter blade 8 is disposed on the subject side, and the shutter blade 8 and a part of the shutter blade 8 are always in contact with each other. There is no case where the blade 7 and the diaphragm member 9 are engaged with each other. Therefore, as described in the above publication, there is no need to partition the two blade chambers by a plate member (intermediate plate), so the area near the exposure opening is at least as thin as the plate member (intermediate plate). In addition, since such a plate member (intermediate plate) becomes unnecessary, the cost can be reduced.

  In this embodiment, the aperture member 9 is formed with an aperture 9b having a smaller diameter than the exposure aperture and covered with the ND filter 10. However, depending on the specifications of the camera, the ND filter 10 may be You may use only the thing which formed the opening part 9b, without using. In this case, a plurality of openings having different apertures that are smaller than the exposure aperture may be formed in the aperture member 9 and rotated by a stepping motor so that a desired aperture can be selected. In addition, it is also possible to cover some of the openings with an ND filter, and in that case, when there are a plurality of openings to be covered with the ND filter, the openings having the same size may be covered with the concentration. It may be covered with a different ND filter.

  Further, as in this embodiment, the aperture member 9 may not be provided with the opening 9b, and the aperture member 9 may be manufactured only from the sheet material of the ND filter. However, in such a configuration, although it is a light quantity control member, it is no longer a diaphragm member. In addition, there is a known diaphragm mechanism whose aperture is controlled by a plurality of diaphragm blades. Even in this case, the diaphragm blade closest to the shutter blade is in any operating state. The object of the present invention can be achieved if the sliding contact relationship between the adjacent shutter blades is always maintained. In this embodiment, the two shutter blades 7 and 8 are employed. However, the present invention can be applied even when the number of the shutter blades is one.

  Next, Embodiment 2 of the present invention will be described with reference to FIGS. The present embodiment differs greatly from the first embodiment in that a diaphragm member 11 and a light shielding member 12 are provided instead of the diaphragm member 9 in the first embodiment. Accordingly, there are some differences in the shapes of the other constituent members. However, substantially the same members and portions are denoted by the same reference numerals, detailed description thereof will be omitted, and only different points will be described.

  First, a configuration unique to the present embodiment will be described with reference to FIG. The diaphragm member 11 has a long hole 11a and an opening 11b having a smaller diameter than the exposure opening, and is attached to the shaft 1w to be rotatable. However, since the opening 11b is not covered with the ND filter 10 unlike the opening 9b of the first embodiment, the auxiliary base plate 2 is not formed with the recess 2c as in the first embodiment. Further, the diaphragm member 11 of the present embodiment is different from the diaphragm member 9 of the first embodiment in its outer shape, but the difference is difficult to understand simply by looking at FIG. To.

  The main base plate 1 of this embodiment is provided with a shaft 1x on the blade chamber side. Further, a light shielding member 12 disposed on the auxiliary base plate 2 side with respect to the diaphragm member 11 is rotatably attached to the shaft 1x. The drive pin 4 a of the motor 4 is fitted in both the long hole 11 a of the aperture member 11 and the long hole 12 a of the light shielding member 12. Therefore, the diaphragm member 11 and the light shielding member 12 are simultaneously rotated by the motor 4, but both have different rotation angles because the distances from the long holes 11a and 12a to the shafts 1w and 1x are different. ing.

  Next, the operation will be described. In the case of the present embodiment, it will be described in the case where it is adopted in a normally open type digital camera. FIG. 6 shows the initial state of this embodiment. That is, at least when the power is on, the diaphragm member 11 and the light shielding member 12 are withdrawn from the exposure opening, and the shutter blades 7 and 8 are fully open. Therefore, the image sensor is exposed to subject light, and the subject image can be observed on the monitor. When the shutter button is pressed in this state, whether to shoot with or without reducing the light amount of the subject is determined based on the measurement result of the subject light. When shooting without reducing the amount of light of the subject, only the shutter blades 7 and 8 are operated, which is exactly the same as in the first embodiment. Therefore, the description in that case will be omitted.

  Therefore, when it is decided to shoot with the subject light amount reduced, the rotor of the motor 4 is rotated counterclockwise, and the diaphragm member 11 and the light shielding member 12 are simultaneously rotated clockwise. Then, the diaphragm member 11 slides with respect to the shutter blade 8, and the tip of the diaphragm member 11 comes into contact with the stopper 1r and stops. FIG. 7 shows the state stopped in this manner. At this time, since the light shielding member 12 has a smaller operating angle than the diaphragm member 11, only a part thereof faces the exposure opening. ing. As can be seen from this, the diaphragm member 11 of this embodiment has the opening 11b facing the exposure opening, but the other areas of the exposure opening are completely covered like the diaphragm member 9 of the first embodiment. The light shielding member 12 covers the lower left region of FIG.

  This means that the throttle member 11 of the present embodiment is smaller than the throttle member 9 of the first embodiment, thereby reducing the diameter of the main base plate 1 and making the entire unit compact. It has become. Therefore, as can be seen from a detailed comparison, the shapes of the shutter blades 7 and 8 are slightly changed. However, the motors 3 and 4 are not changed in the configuration and the mounting position with respect to the center of the optical axis. As for the arrangement relationship with the lens, the same conditions as in the case of Example 1 can be obtained. However, if the arrangement position of the motors 3 and 4 can be slightly moved in relation to the photographing lens, the size can be further reduced. In addition, it may seem that this kind of downsizing is not a big deal, but in the world where the actual unit diameter is 30 to 35 mm, downsizing of 0.5 to 1 mm is extremely valuable. .

  In this way, when the state of FIG. 7 is obtained, a shooting start signal is then given to the imaging apparatus, and after a predetermined shooting time has elapsed, the motor 3 is energized and the rotor is rotated clockwise. . Therefore, the shutter blades 7 and 8 rotate in opposite directions, close the opening 11b, and then come into contact with the stoppers 1t and 1q and stop. The stop state is shown in FIG. Thereafter, when imaging information is transferred to the storage device in this closed state, a current in the reverse direction is supplied to the motors 3 and 4, and the shutter blades 7 and 8, the diaphragm member 11, and the light shielding member 12 are Both are rotated in the opposite direction. The shutter blades 7 and 8 are stopped by abutting against the stoppers 1q and 1t, and the aperture member 11 and the light shielding member 12 are stopped when the aperture member 11 abuts on the stopper 1s. Immediately thereafter, the motors 3 and 4 are de-energized to return to the initial state of FIG.

  As described above, according to the present embodiment, in any operating state, a part of the shutter blade 8 and a part of the diaphragm member 11 are always kept in contact with each other, and their contact areas are continuously changed. Since it is comprised so that it may go, the board member (intermediate board) for dividing into two blade chambers as described in said gazette becomes unnecessary. Therefore, according to the present embodiment, at least the area near the exposure opening can be made thinner by that amount, and such a plate member (intermediate plate) becomes unnecessary, which is costly. In addition to the advantage, the planar area of the unit can be made smaller than in the first embodiment. In the present embodiment, the opening 11b of the diaphragm member 11 is not covered by the ND filter, but may be configured to cover the same as in the first embodiment. Further, the shutter blade is not limited to the configuration of the present embodiment.

  In each of the embodiments described above, the state in which the aperture members 9 and 11 are retracted from the exposure opening is the initial state, but the state in which they are inserted into the exposure opening may be the initial state. The shutter blades 7 and 8 may be closed when the camera is not used, and may be fully opened when the power is turned on. In this case, the performance of the image sensor can be prevented from being deteriorated. It becomes possible. Furthermore, when applied to a film camera, the shutter blades 7 and 8 are closed regardless of whether the power is on or off when shooting is not being performed. Then, the shutter blades 7 and 8 may be opened and closed.

DESCRIPTION OF SYMBOLS 1 Main ground plate 1a, 2a, 9b, 11b Opening part 1b, 1c, 1d, 1j Attachment part 1e, 1f, 1i Hook part 1g, 1h, 7a, 8a, 9a, 11a, 12a Long hole 1k, 1m, 1n, 1p Spacer 1q, 1r, 1s, 1t Stopper 1u, 1v, 1w, 1x Shaft 2 Auxiliary base plate 2b Hole 2c Recess 3, 4 Motor 3a, 4a Drive pin 5, 6 Screw 7, 8 Shutter blade 9, 11 Aperture member 10 ND filter 12 Shading member

Claims (2)

Two ground planes forming a circular exposure opening by forming one blade chamber between them and overlapping the openings of both,
At least one shutter blade disposed in the blade chamber for opening and closing the exposure opening;
A first motor attached to one of the base plates outside the blade chamber and having an output portion extending into the blade chamber to open and close the shutter blade;
What is the adjacent shutter blade, which is composed of a first member disposed in the blade chamber and having an opening having a smaller aperture than the exposure opening and a second member having a light shielding function. Even in the operating state, the first member and the edge of the exposure opening are moved in a state in which a part of the exposure opening is advanced and retracted so that a part thereof overlaps and the opening of the first member enters the exposure opening. A light amount control means for covering the gap formed between the second member,
A second motor attached to one of the base plates outside the blade chamber and having an output portion extending into the blade chamber and causing the light amount control means to perform the advance / retreat operation;
A lens shutter for a camera.   The camera lens shutter according to claim 1, wherein the opening of the first member is covered with an ND filter sheet.

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