JP2006330314A - Light quantity adjusting device, imaging optical unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that other magnetic circuit may be affected by the inflow of leakage flux in a light quantity adjusting device formed by using yokes constituting a plurality of magnetic circuits in common as a base member. <P>SOLUTION: The light quantity adjusting device is equipped with: a plurality of light shielding members 3 and 4 controlling light quantity; a plurality of driving means 5 and 5' respectively driving the plurality of light shielding members 3 and 4 by obtaining electromagnetic driving force in the magnetic circuit; and the base member 1 to which the plurality of light shielding members 3 and 4 and the plurality of driving means 5 and 5' are attached. The base member 1 serves as the yokes Y and Y' constituting the magnetic circuit of the plurality of driving means 5 and 5', and the yokes used for the plurality of driving means 5 and 5' use the common yoke. The base member 1 is provided with a prevention means 1K preventing the inflow of the leakage flux at the middle part of the plurality of driving means 5 and 5'. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light amount adjusting device used for a digital camera or the like, for example, a light amount adjusting device including an aperture blade that performs an aperture operation and a shutter blade that performs an exposure operation, an imaging optical unit including the light amount adjusting device, and the imaging optical The present invention relates to an imaging apparatus including a unit.

  2. Description of the Related Art In recent years, with regard to camera shutter devices and diaphragm devices used in digital cameras and camera-equipped mobile phones, there has been an increasing demand for miniaturization and thinning as digital cameras and camera-equipped mobile phones become smaller and thinner. Yes.

  Among them, as a conventional example intended for downsizing, an aperture / shutter having a shutter blade that opens and closes an opening for exposure and a diaphragm blade that stops an aperture is separately provided on a base plate having an exposure opening. The diaphragm blades are movably supported by a predetermined distance, and the aperture opening formed by the two diaphragm blades is opened and closed by a single shutter. It has been proposed that a drive source for driving and a drive source for driving the shutter are separately provided, and these drive sources are constituted by so-called moving magnet motors. (Patent Document 1).

  In addition, the driving source is different from the above-described example, and two opening shutters are supported to be movable relative to each other by a predetermined distance with respect to the ground plate having the exposure opening. Two closing shutters are supported so as to be able to move relative to each other at a position facing each other through the exposure opening, and a driving source for driving the closing shutter and the opening shutter is separately provided. A configuration is proposed. (Patent Document 2).

These drive sources are magnetized with different magnetic poles (N pole and S pole) so as to bisect the outer peripheral surface, and face the rotor rotating in a predetermined angle range, the exciting coil, and the outer peripheral surface of the rotor. It is comprised from the plate-shaped yoke formed in the forked shape which has two magnetic poles arrange | positioned in this way and can generate | occur | produce different magnetic poles.
JP 2002-139768 A JP 2003-186079 A

  In the conventional light quantity adjusting device described above, the magnetism of one electromagnetic actuator acts on the other electromagnetic actuator due to variations in the position accuracy of the yoke member. For example, as described above, the shutter driving actuator and the diaphragm blade driving actuator At the operation start position and the operation end position rotated by a predetermined distance, a magnetic attraction force acting between the yoke and the rotor acts so as to maintain the position even when the coil is de-energized. In some cases, the operation start position and the operation end position cannot be maintained, and the individual yoke positions may be adjusted by post-processing.

  Further, in the light amount adjusting device disclosed in the above prior art, the former light amount adjusting device uses a so-called moving magnet type motor as a drive source, and the height is inevitably high due to the structure of the rotor and the coil. Inevitably, it is not suitable for thinning the device.

  Furthermore, the drive source of the latter light quantity adjusting device is shorter than a moving magnet type motor because of the use of a flat yoke, but the ground plate on which the drive source is placed Is formed by a mold, and a predetermined thickness is required to maintain the strength. As a result, there is a limit to thinning the apparatus.

  In view of such a background, the present applicant has proposed a light quantity adjusting device that combines a base member and a yoke, constitutes a magnetic circuit using the yoke, and constitutes a driving means for driving a plurality of light shielding members. According to this light quantity adjusting device, by using the base member and the yoke in common, parts can be omitted, and in particular, the device can be thinned.

  However, since a plurality of magnetic circuits are configured in a single yoke that also serves as a base member, there may be a problem that the magnetic flux of one magnetic actuator passes through the yoke and affects the other magnetic actuator.

  The invention according to the present application has been made in view of such conventional problems, and can provide a more inexpensive light amount adjusting device that can reduce magnetic interference and reduce the overall size of the device, in particular, the thickness of the device. Objective.

  Furthermore, by reducing the thickness of the light amount adjusting device, an imaging optical unit that reduces the thickness of the lens unit including them, and an imaging device that reduces the size and thickness of an imaging device such as a digital camera or a camera-equipped mobile phone are provided. The purpose is to.

  The configuration of the light amount adjusting device that realizes the object of the present invention includes a plurality of light shielding members for controlling the light amount, and an electromagnetic driving force obtained by a magnetic circuit to obtain the plurality of light shielding members. A plurality of driving means for driving each of the plurality of driving means; and a base member to which the plurality of light shielding members and the plurality of driving means are attached. The base member also serves as a yoke constituting the magnetic circuit of the plurality of driving means. In the light amount adjusting device using a common yoke as the drive means, the base member is provided with a blocking means for blocking the inflow of leakage magnetic flux at the intermediate portion of the plurality of drive means. .

  The configuration of the imaging optical unit that realizes the object of the present invention is to unitize the above light amount adjusting device and an imaging optical system in which at least a lens is arranged in front of or behind the light amount adjusting device, and at least a part of the yoke is The optical axis center side enters from the outer periphery of the lens of the imaging optical system closest to the yoke.

  The configuration of an imaging apparatus that realizes the object of the present invention includes the light amount adjusting device having the above-described configuration and an imaging optical system in which at least a lens is disposed in front of or behind the light amount adjusting device.

  According to the light quantity adjusting device of the present invention, the base member and the yoke constituting the magnetic drive circuit are used together, and the blocking means for blocking the inflow of leakage magnetic flux (blocking magnetic interference) is provided at the intermediate portion of the plurality of magnetic actuators. This makes it possible to prevent the problem of magnetically affecting the other magnetic actuator of one magnetic actuator, which is caused by configuring a plurality of magnetic circuits in a single yoke that also serves as a base member. Therefore, it is possible to reduce the thickness of the image pickup optical unit and the image pickup apparatus using the light amount adjusting device.

First Embodiment FIGS. 1 to 5 show a first embodiment of the present invention.

  FIG. 1 is a plan view of a state in which a cover 10 to be described later is removed. The shutter blade 3 is in a closed state, and the aperture blade 4 for limiting the amount of light is in an open state. 2 shows a state in which the shutter blade 3, the diaphragm blade 4 and the bearing member 7 are removed from FIG. 3, FIG. 3 shows a state in which both the shutter blade 3 and the diaphragm blade 4 are open, and FIG. Fig. 5a is a plan view showing a state where the cover 10 is attached to the base member 1, and Fig. 5b is a cross-sectional view taken along the line AA of Fig. 5a.

  In this embodiment, as shown in FIGS. 1 to 5, an opening 2 that transmits imaging light is provided in a base member 1 that also serves as a yoke. The base member 1 is formed into a predetermined shape by pressing a plate material made of a yoke material made of a ferromagnetic material such as pure iron, electromagnetic stainless steel, permalloy, or silicon steel plate.

  1 and 2, the base member 1 is formed substantially symmetrical with respect to the left and right in FIG. 1 and FIG. To distinguish.

  The base member 1 has a yoke Y formed such that the magnetic pole portions 1a and 1b are magnetically substantially U-shaped, and similarly, the magnetic pole portions 1a 'and 1b' are substantially U-shaped. The yoke Y ′ is formed. At the center between the opposing magnetic pole parts 1a and 1b and between the magnetic pole parts 1a 'and 1b', the rotor 5 and 5 'for driving the shutter blade 3 and the diaphragm blade 4 to rotate at a predetermined angle rotate through a predetermined gap. Each is supported as possible. The left rotor 5 is rotatably supported by a shaft 7a formed on a bearing member 7 shown in FIG. 5b, which is attached to the base member 1 by an appropriate method.

  Further, the left and right magnetic pole portions 1b, 1b 'are cut and bent into an arc shape to increase the area facing the rotors 5, 5', and have a width that is approximately the same as the height of the outer peripheral surface of the rotors 5, 5 '. Standing up at. The opposing magnetic pole portions 1a and 1a ′ are respectively inserted with bobbins 6 and 6 ′ around which exciting coils 8 and 8 ′ are wound, and the bobbins 6 and 6 ′ have terminals 9 and 9 as output terminals, respectively. 'Is provided.

  As shown in FIG. 5b, the magnetic pole portions 1a and 1a ′ have the same height as the outer peripheral surface of the rotors 5 and 5 ′ in order to increase the area facing the rotors 5 and 5 ′. Further, a flat plate 1j having the same shape as the magnetic pole portions 1a and 1a 'and having a predetermined thickness is fixed by an appropriate means such as caulking or bonding.

  A concave groove 1K having a predetermined depth and a predetermined length is provided at an intermediate portion between the yokes Y and Y ′ of the base member 1 by an appropriate means such as cutting or pressing.

Rotation support structure of shutter blade 3 and diaphragm blade 4 The rotation support structure of shutter blade 3 and diaphragm blade 4 is as follows. The shutter blade 3 is fitted with a shaft 7b formed so as to protrude from a bearing member 7 fixed to the lower portion of the base member 1, and a hole 3a of the shutter blade 3 is fitted to form a rotation center. 7b passes through a hole 1e formed on the base member 1 and fits into the hole 3a of the shutter blade 3 on the base member 1. As a result, the shutter blade 3 is supported to be rotatable by a predetermined angle. .

  On the base 1, stoppers 1d and 1c for defining an opening position and a closing position corresponding to the rotation of the shutter blade 3 are integrally formed by a method such as cutting and bending.

  Similarly, the aperture blade 4 is fitted to a shaft 7b 'formed so as to protrude from a bearing member (not shown) fixed to the lower portion of the base member 1, and the aperture blade 4 is fitted with a hole 4a to form a rotation center. At the same time, the shaft 7b 'passes through a hole 1e' formed on the base member 1 and is fitted to the hole 4a 'of the diaphragm blade 4 on the base member 1. As a result, the diaphragm blade 4 The angle is supported to be rotatable. On the base 1, stoppers 1d 'and 1c' for defining an opening position and a closing position corresponding to the rotation of the diaphragm blade 4 are integrally formed by a method such as cutting and bending.

  As described above, the shutter blade 3 is supported so that the hole 3a is rotatable on the shaft 7b. On the other hand, a driving pin 5a formed integrally with the rotor 5 is formed on the shutter blade 3. It is loosely fitted in the long groove-shaped long hole 3b. The tip of the shutter blade 3 has an area enough to cover the opening 2. The shutter blade 3 and the diaphragm blade 4 have light shielding properties and lubricity, and are formed by pressing a thermoplastic sheet having a thickness of 0.03 to 0.15 mm.

  As described above, the aperture blade 4 is supported so that the hole 4a can rotate on the shaft 7b '. On the other hand, a drive pin 5a' formed integrally with the rotor 5 'is provided on the aperture blade 4. It is loosely fitted in the formed long groove shaped long hole 4b '. The aperture blade 4 has a small aperture 4c smaller than the aperture 2 at the tip.

  The base 1 is provided with holes 1g, 1g 'and 1f. The holes 1g and 1g 'are for attaching the light amount adjusting device to a camera body (not shown), and the holes 1f are for attaching and fixing the cover member 10.

  The cover 10 covers the movable area of the shutter blade 3 and the diaphragm blade 4 and prevents the shutter blade 3 and the diaphragm blade 4 from floating up. The cover 10 is made of a metal or plastic thin plate, and is fixed to the positioning hole 1f on the base 1 by an appropriate method. The lower side is fitted and fixed to the base 1 by the flexibility of the cover 10 as shown in FIG. 5a. The

  Next, the operation of the light amount adjusting device of this embodiment will be described.

  First, before a shutter release button of a camera (not shown) is pressed, the shutter blades 3 and the diaphragm blades 4 overlap each other and are retracted from the opening 2 as shown in FIG.

  In this state, as shown in FIG. 3, the left shutter blade rotor 5 constituting the shutter blade driving device is acted on by a force to rotate clockwise by the magnetic attractive force, and the shutter blade 3 is a stopper. Locked by 1d, the open state is maintained. On the other hand, as shown in FIG. 3, the right diaphragm blade rotor 5 'constituting the diaphragm blade driving device is acted on by a magnetic attraction force to rotate counterclockwise, and the diaphragm blade 4 is a stopper. It is locked by 1d ', and the open state is maintained.

  Next, when the release button is pressed, the image sensor (not shown) releases the accumulated charge, accumulates a predetermined exposure amount, and then closes the shutter blade group to end the exposure, and then accumulates the accumulated charge. Transfer.

  At that time, when the coil 8 is energized by a drive circuit (not shown), the magnetic pole portions 1a and 1b become N pole and S pole, respectively, and the rotor 5 starts to rotate counterclockwise. As the rotor 5 rotates counterclockwise, the drive pin 5a provided integrally with the rotor 5 also starts to rotate counterclockwise. As the drive pin 5a rotates, the inner wall portion on the right side in FIG. 4 of the long groove 3a formed in the shutter blade 3 is pressed counterclockwise. The shutter blade 3 rotates clockwise about the shaft 7b. It rotates to close the opening 2 and reach the state shown in FIG.

  In the closed state of the shutter blade 3, even if the coil 8 is de-energized, the rotor 5 is forced to rotate counterclockwise by the magnetic attractive force, and the shutter blade 3 is also rotated clockwise by the force. Although it is going to be stopped, it is latched by the stopper 1c and a closed state is maintained.

  At this time, the shutter blade 3 and the aperture blade 4 are always partially overlapped at any position from the fully open state to the fully closed state, and the blades do not interfere with each other.

  Next, when the charge transfer of the image sensor is completed, the shutter blade 3 is opened again. At this time, the driving means for the shutter blades drives the drive pin 5a in the opposite direction to that during the shutter closing operation. The operation is performed in the reverse direction from the fully open to fully closed operation, which has been described so far.

  Next, the operation of the aperture blade 4 will be described.

  When the exposure amount is determined by an exposure control mechanism (not shown), when the coil 8 'is energized by a drive circuit (not shown), the magnetic pole portions 1a' and 1b 'become the S pole and the N pole, respectively, and the rotor 5' Begins rotating in the direction. Along with the rotation of the rotor 5 ′, the drive pin 5a ′ provided integrally with the rotor 5 ′ also starts to rotate clockwise. As the drive pin 5a ′ rotates, the inner wall portion on the left side in FIG. 4 of the long groove 4b ′ formed in the diaphragm blade 4 is pressed in the clockwise direction. Rotating clockwise, the opening 2 is limited to a small aperture diameter 4c as shown in FIG.

In the closed state, even if the coil 8 'is de-energized, the rotor 5' exerts a force to rotate clockwise by the magnetic attractive force, and the diaphragm blade 4 tries to rotate counterclockwise by the force. However, the closed state is maintained by being locked by the stopper 1c '.
At this time, the shutter blade 3 and the aperture blade 4 are always partially overlapped at any position from the fully open state to the fully closed state, and the blades do not interfere with each other.

  When the shutter blade 3 described above is driven, the excited magnetic flux flows in a closed loop from the N pole of the magnetic pole part 1a of the substantially U-shaped yoke Y to the S pole of the magnetic pole part 1b. However, since the yoke Y and the yoke Y ′ use a common yoke member, most of the magnetic flux flows as described above, but a part leaks to the adjacent yoke Y ′. When this leakage magnetic flux flows through the yoke Y ′ and the leakage magnetic flux amount is large, a rotational driving force acts on the diaphragm driving mechanism. As described above, when no driving current flows through the diaphragm driving mechanism, a magnetic attractive force is exerted on the rotor 5 ′. This causes a force to rotate in the clockwise direction, and the diaphragm blade 4 also attempts to rotate in the counterclockwise direction due to the force, but the initial position state is maintained by being locked by the stopper 1c ′. When a leakage magnetic flux that causes a driving force exceeding the attractive force flows, the diaphragm blade 4 may move, and the diaphragm blade 4 may be in a closed state. Even if this state does not occur, if the leakage magnetic flux flows into the yoke Y ′ and the rotational driving force acts on the diaphragm driving mechanism, the clockwise driving force acts on the diaphragm blade 4 and the initial position becomes unstable. When this force is applied, the aperture blade 4 may move and become closed.

  According to this embodiment, since the concave groove portion 1K having a predetermined depth and a predetermined length is provided at the intermediate portion between the yokes Y and Y ′ of the base member 1, the magnetic path cross-sectional area of the yokes Y and Y ′ is provided. Compared to the above, the magnetic path cross-sectional area of the concave groove 1K is small. For this reason, even if leakage magnetic flux tries to flow into the yoke Y ′, the amount of magnetic flux flowing is proportional to the cross-sectional area of the magnetic path, so that the magnetic flux is saturated at the concave groove 1K and a slight amount is present in the yoke Y ′. Only flows.

In the above description, the leakage magnetic flux inflow prevention method at the time of driving the shutter blade 3 has been described, but the same can be said when the diaphragm blade 4 is driven. In this case, when the diaphragm blade 4 is driven to reduce the light amount to the predetermined opening, if the shutter blade 3 is driven, the opening 2 is fully closed, and the light amount cannot be reduced. It is possible to say. However, since the inflow of leakage magnetic flux is blocked by the action of the concave groove 1K described above, the shutter blade 3 is not driven by the influence of the leakage magnetic flux when the diaphragm blade 4 is driven.
Second Embodiment FIG. 6 shows a second embodiment of the present invention.

  The second embodiment shows a configuration in which the above-described leakage flux inflow amount is made smaller than that of the first embodiment.

In this embodiment, instead of the concave groove portion 1K in the first embodiment shown in FIG. 1, a gap portion 1L which is an air gap having a predetermined width and a predetermined length is provided at the same place. By forming the air gap 1L, which is an air gap, between the yokes Y and Y ′, the magnetic resistance is further increased, the magnetic flux becomes stronger against leakage magnetic flux inflow, and the influence of the leakage magnetic flux on the other side is minimized. can do.
Third Embodiment FIG. 7 shows a third embodiment of the present invention.

  FIG. 7 shows a modification of the second embodiment shown in FIG. In the second embodiment shown in FIG. 6, the gap 1L is provided in the base member 1 as the leakage flux inflow prevention portion. However, since only this portion is cut, the mechanical strength as the light quantity adjusting device is increased. It may be reduced.

Therefore, in the third embodiment, the gap 1L is filled into the gap 1L by means such as press-fitting and bonding a nonmagnetic member 1M such as brass. As a result, there is no fear that the mechanical strength as the light amount adjusting device is lowered, and the magnetic resistance is large and the magnetic flux becomes strong against leakage flux inflow.
Fourth Embodiment FIG. 8 shows a fourth embodiment of the present invention.

This embodiment shows a lens unit LU in which the light amount adjusting device E shown in the first, second or third embodiment and the lenses 11 and 12 are integrally assembled through a holding member 13 to form a unit. Yes.
Fifth Embodiment FIGS. 9 and 10 show a fifth embodiment of the present invention.

  FIG. 9 shows a light amount adjusting device E shown in the first, second or third embodiment, or the fourth embodiment in an image pickup optical system of a digital camera 15 having an image pickup device 14 such as a CCD or CMOS sensor as an image pickup means. The lens unit LU shown in FIG. 2 is disposed, and the camera can be thinned by reducing the thickness of the imaging optical system of the camera due to the above-described effects.

  FIG. 10 shows a mobile terminal device in which the light amount adjusting device E and the lens 17 shown in the first, second or third embodiment are arranged. Since the arrangement position of the lens 17 with respect to the light amount adjusting device E is not limited as compared with the yoke as in the conventional case, the above-described effects can further reduce the size of the camera-equipped mobile phone that is a thin and narrow mobile terminal. Can contribute.

It is a top view of the light quantity adjustment apparatus in 1st Example of this invention, A shutter blade | wing shows a closed state and an aperture blade shows an open state. The figure which shows the arrangement | positioning state of the base member of FIG. 1, a rotor, and a coil bobbin. It is a top view of the light quantity adjustment apparatus in 1st Example of this invention, and a shutter blade | wing and an aperture blade show an open state. It is a top view of the light quantity adjustment apparatus in 1st Example of this invention, A shutter blade | wing shows an open state and an aperture blade shows a closed state. The top view which attached the cover member to the light quantity adjustment apparatus of FIG. FIG. 5B is a cross-sectional view taken along line AA in FIG. The top view of the base member in the light quantity adjustment apparatus which shows the 2nd Example of this invention. The top view of the base member in the light quantity adjustment apparatus which shows the 3rd Example of this invention. Sectional drawing of the lens unit which shows the 4th Example of this invention. Schematic of the camera which shows the 5th Example of this invention. Schematic of the camera-equipped mobile phone as the mobile terminal showing the fifth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base member 1K Concave groove part 1L Cavity part 1M Nonmagnetic member 2 Opening 3 Shutter blade 4 Diaphragm blade 5 Rotor 6 Bobbin 7 Bearing member 8 Excitation coil 9 Terminal Y, Y 'Yoke

Claims (10)

A plurality of light shielding members for controlling the amount of light, a plurality of driving means for respectively driving the plurality of light shielding members by obtaining an electromagnetic driving force in a magnetic circuit, and a base for mounting the plurality of light shielding members and the plurality of driving means A light amount adjusting device using a common yoke as a yoke for constituting the magnetic circuit of the plurality of drive means, and the yoke used for the plurality of drive means is a base member; A light quantity adjusting device characterized in that blocking means for blocking inflow of leakage magnetic flux is provided at an intermediate portion of the plurality of driving means. The light amount adjusting device according to claim 1, wherein the blocking unit is configured by a thin portion or a notch portion. The light amount adjusting device according to claim 2, wherein a rigid body made of a material different from a material of the base member is provided in the notch portion as the blocking means. The light quantity adjusting device according to claim 3, wherein the material of the rigid body is a non-magnetic material.   The light amount adjusting device according to claim 1, wherein the base member is formed with a circular opening that transmits imaging light.   The driving means includes at least a magnet magnetized in two poles in the circumferential direction, the yoke disposed in the circumferential direction of the magnet, and a bobbin fitted around a part of the yoke and wound with a coil The light quantity adjusting device according to any one of claims 1 to 5, wherein   The light quantity adjusting device according to claim 1, wherein the plurality of light shielding members are a combination of shutter members, a combination of diaphragm members, or a combination of a shutter member and a diaphragm member.   8. The light quantity adjusting device according to claim 1 and an imaging optical system in which at least a lens is arranged in front of or behind the light quantity adjusting device are unitized, and at least a part of the yoke is the most to the yoke. An imaging optical unit characterized in that it enters the optical axis center side from the outer periphery of the lens of the imaging optical system that is in close proximity.   8. An image pickup apparatus comprising: the light amount adjusting device according to claim 1; and an image pickup optical system in which at least a lens is disposed in front of or behind the light amount adjuster. An imaging apparatus comprising the imaging optical unit according to claim 8.

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