JP5380873B2 - Drive mechanism, lens barrel and camera including the same - Google Patents

Description

  The present invention relates to a driving mechanism and a lens barrel and a camera including the driving mechanism.

2. Description of the Related Art Conventionally, there has been a technique in which a relative positional relationship between cylinder members that move relative to each other is detected using a brush and a code plate when zooming or focusing a lens barrel of a camera (see, for example, Patent Document 1) ).
Japanese Patent Laid-Open No. 9-230111

  However, when a brush or a code plate is used, it is necessary to attach the code plate to the cylinder or to provide a brush, which increases the number of parts and makes it difficult to reduce the size of the apparatus. An object of the present invention is to detect with a simple structure that two members that move relative to each other such as a cylindrical member in a lens barrel are in a predetermined positional relationship.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

The invention according to claim 1 is a drive mechanism of the zoom lens, and has a cam groove for changing a focal length of the zoom lens by driving a lens constituting the zoom lens in an optical axis direction. A cam cylinder in which metal plating is formed as a conductive portion on the inner peripheral surface so as to intersect the cam groove at the wide position and the tele position of the cam groove, and a conductive follower pin that engages with the cam groove. , and a movable cylinder that moves relative to the cam barrel while moving along the follower pin into the cam groove, wherein when the follower pin has the conducting portion by moving the cam groove comes at the intersection to, by said conductive portion and said follower pin is conductive, the position of the movable cylinder relative to the cam barrel is detectable be in the wide position or telephoto position, the in the cam groove Portion passing portion intersect is driven Organization which is a flat portion extending in a direction perpendicular to the axis of the cam barrel.
The invention according to claim 2 is the drive mechanism according to claim 1 , wherein the conducting portion includes a first conducting portion that intersects the cam groove at a wide position of the cam groove, and the cam groove. A second conducting portion that intersects the cam groove at the tele position, and is connected to different circuits, and when the follower pin moves through the cam groove and reaches the position where the conducting portions intersect , in each circuit, the by detecting conduction between the conductive portion and the follower pin, is driven Organization that said cam cylinder and the movable cylinder is characterized in that the possible decision that a predetermined positional relationship .
The invention of claim 3 is a drive Organization of claim 1 or claim 2, the two-color molded with the plating easily wood charge and plated hard wood charge, the plating tends timber fees in a drive Organization, characterized in that the surface of the molded part is formed by applying metal plating.
The invention of claim 4 is a lens barrel, characterized in that it comprises a driving Organization according to any one of claims 1 to 3.
The invention of claim 5 is a camera, characterized in that it comprises a driving Organization according to any one of claims 1 to 3.

  According to the present invention, it is possible to detect with a simple structure that two members that move relative to each other, such as a cylindrical member in a lens barrel, are in a predetermined positional relationship.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure shown below is provided with an XYZ orthogonal coordinate system for ease of explanation and understanding. In this coordinate system, the direction toward the left side as viewed from the photographer at the position of the camera when the photographer shoots a horizontally long image with the optical axis horizontal (hereinafter referred to as a normal photographing position) is the X plus direction. In addition, a direction toward the upper side at a normal photographing position is a Y plus direction. Furthermore, the direction toward the subject at the normal shooting position is the Z plus direction.

  The drive mechanism 1 of this embodiment is a drive mechanism of a retractable lens barrel 2 used in, for example, an optical three-group type non-interchangeable digital camera 100. 1 to 3 are cross-sectional views including the optical axis of a lens barrel 2 provided with a drive mechanism 1. FIG. 1 shows a retracted state in the lens barrel 2, FIG. 2 shows a wide state, and FIG. 3 shows a tele state. Show.

  The lens barrel 2 includes a first lens group L1, a second lens group L2, a third lens group L3, a CCD 10, a CCD base 12, a fixed cylinder 20, a cam cylinder 30, a first lens group cylinder 40, a rectilinear cylinder 50, and A second lens group tube 60 is provided.

  The first lens group L1, the second lens group L2, and the third lens group L3 constitute a zoom lens having a three-group structure, and are sequentially arranged from the subject side (Z plus side) along the optical axis direction. ing.

  The CCD 10 is a solid-state imaging device that converts the subject image formed by the zoom lens described above into an electrical signal, and is disposed on the exit side of the third lens group L3. The CCD table 12 is provided at the end on the Z minus side of the lens barrel 2 and is disposed substantially orthogonal to the optical axis. A CCD 10 is fixed at a substantially central portion of the CCD table 12.

  The fixed cylinder 20 is fixed to the CCD table 12 with screws 21. The fixed cylinder 20 has a cam groove 22 that engages with a cam follower pin 31 (shown in FIGS. 2 and 3) of the cam cylinder 30 and a rectilinear guide groove that guides the protrusion 51 of the rectilinear cylinder 50. 23 is formed. Further, a part of the outer periphery of the fixed cylinder 20 slightly on the Z plus side from the center protrudes outward, and the main board 3 is attached to the protruding part.

  The cam cylinder 30 is a cylinder inserted on the inner diameter side of the fixed cylinder 20, and has a cam groove 32 for driving the first lens group cylinder 40 and a cam groove for driving the second lens group cylinder 60 on the inner peripheral surface. 33 is formed. A cam follower pin 31 to be inserted into the cam groove 22 of the fixed cylinder 20 is press-fitted on the outer peripheral surface (see FIG. 2). On the inner peripheral surface in the Z minus direction, there is provided a groove 34 that engages with a protrusion 52 of a straight cylinder 50 described later. Further, the cam barrel 30 is provided with a gear 35 on the outer surface on the Z minus side, and the optical axis is driven by a driving device (not shown) when the lens barrel 2 is driven to move between the retracted state, the wide state and the tele state. It is driven to rotate around. By this rotation, the cam cylinder 30 is rotated with respect to the fixed cylinder 20 by the cam groove 22 and is movable in the optical axis direction. Further, the rectilinear cylinder 50, the first lens group cylinder 40, and the second lens group cylinder 60 are moved along the optical axis. Drive in the direction.

  The first lens group tube 40 is disposed on the inner diameter side of the cam tube 30. Further, a first lens group chamber 41 to which the first lens group L1 is fixed is fixed to the inner diameter side of the first lens group cylinder 40 on the Z plus side. Further, the groove 42 on the inner periphery of the first lens group tube 40 and a protrusion 52 (described later) of the rectilinear tube 50 are engaged, and are linearly guided in the optical axis direction. Therefore, the first lens group cylinder 40 advances and retracts in the optical axis direction while being guided by the rectilinear cylinder 50 along the activation of the cam cylinder 30. Further, a metal cam follower pin 43 inserted into the cam groove 22 of the cam cylinder 30 is press-fitted into the outer peripheral surface of the first lens group cylinder 40.

  The rectilinear cylinder 50 is a cylinder that is inserted on the inner diameter side of the first lens group cylinder 40, and includes a protrusion 51 that is formed radially outward at the end on the Z minus side. Further, a protrusion 51 that engages with the straight guide groove 23 is provided on the outer peripheral side of the flange portion 42 to restrict rotation. Further, a protrusion 52 is also provided on the outer periphery of the rectilinear cylinder 50 and engages with the groove 34 provided on the inner periphery of the cam cylinder 30 as described above, and the rectilinear cylinder 50 is integrated with the cam cylinder 30, It advances and retreats in the optical axis direction while being guided by the groove 23 of the fixed cylinder 20. Further, a contact piece 54 is held by heat caulking on the Z minus side end surface of the protruding portion 51 of the rectilinear cylinder 50 and is in contact with the groove of the fixed cylinder 20.

  The second lens group cylinder 60 is a cylinder that is inserted on the inner diameter side of the rectilinear cylinder 50 and is a moving cylinder that is driven by the cam cylinder 30 in the optical axis direction. The second lens group cylinder 60 is press-fitted with a cam follower pin 61 inserted into the cam groove 33 of the cam cylinder 30 through the rectilinear guide groove 53 formed in the rectilinear cylinder 50 described above on the outer peripheral surface thereof. The lens group tube 60 advances and retreats in the optical axis direction while being guided by the rectilinear tube 50 along the start of the cam tube 30.

  The third lens group L3 is supported by the third lens group chamber 70. The third lens group chamber 70 is guided in a straight line by a guide shaft 71 and controlled in the optical axis direction by a stepping motor 72. A resin shaft 13 provided on the CCD table 12 restricts the rotation of the third lens group chamber 70.

  In this lens barrel 1, the fixed barrel 20, the cam barrel 30, and the rectilinear barrel 50 are manufactured by two-color molding of a first material A that is easily metal-plated and a second material B that is less likely to be metal-plated. As these materials, for example, ABS resin for plating is used as the first material A, and polycarbonate is used as the second material B.

  For example, in the two-color molding, the second material B is injected into a mold to mold the fixed cylinder 20, the cam cylinder 30, and the portion of the straight cylinder 50 as a base, and then the mold A part is exchanged or moved, and the first material A is injected into a space formed by the exchange or movement. When a chemical plating process is performed on a member manufactured by this two-color molding, only the surface of the first material A that is easily gold-plated is plated, and the surface of the second material B that is difficult to be gold-plated is not plated. As the chemical plating process, first, a chemical plating process for plating copper on the surface of the first material A as a base is performed, and then a chemical plating process for plating gold on the copper is performed. Thereby, the gold conduction | electrical_connection part C is formed.

  FIG. 4 is a development view of the inner surface of the fixed cylinder 20. The first material A that is easily plated in the fixed cylinder 20 is provided at three locations. The first portion 24 is a portion extending from the bottom of the straight guide groove 23. As shown in FIGS. 1 to 3, the portion extending from the bottom portion also forms a screw mounting portion 25 that protrudes to the outer peripheral side of the fixed cylinder 20 at the Z minus side end. And the conduction | electrical_connection part C formed by plating the surface is extended with the bottom part of the rectilinear guide groove 23, the Z minus side end surface of the screw attachment part 25, and the inside of the screw hole for screw attachment. Therefore, by screwing the screw 21 into the screw hole with the FPC 28 interposed therebetween, the bottom 24 of the linear guide groove 23 and the FPC 28 are electrically connected. The FPC 28 is connected to the main board 3.

  The second portion 26 is a portion of the cam groove 22 where the cam follower pin 31 is at the wide end. As shown in a cross section in FIG. 2, the second portion 26 is provided so as to pass through the outer surface from the inner surface of the fixed cylinder 20 and continue to the main substrate 3, and the second portion 26 has a bottom portion of the cam groove 22. Is provided with a through hole 26a. The conduction portion C extends from the inner surface of the cam cylinder 30 to the outer surface side through the inner surface of the through hole 26 a and continues to the main substrate 3 by the FPC 29.

  The third portion 27 is a portion of the cam groove 22 where the cam follower pin 31 is at the tele end. Similarly to the second portion 26, the third portion 27 is provided so as to pass through the outer surface from the inner surface of the fixed cylinder 20 and continue to the main substrate 3, and the through hole 27 a is formed at the bottom of the cam groove 22. The conductive portion C by plating extends from the inner surface of the cam cylinder 30 to the outer surface through the inner surface of the through hole, and continues to the main substrate 3 by FPC.

  FIG. 5 is a development view of the inner surface of the cam cylinder 30. As shown in FIGS. 1-4, the 1st material A which is easy to plate in the cam cylinder 30 is provided in two places. The first portion 36 includes a portion 36 a where the cam follower pin 31 is press-fitted on the outer surface of the cam cylinder 30, a portion 43 a that passes when the cam follower pin 43 is in the wide position in the cam groove 32, and a cam follower pin in the cam groove 33. It is formed to extend to the Z minus end of the cam cylinder 30 through the portion 61a that passes when 61 is in the wide position.

  Here, the portion 43a through which the cam follower pin 43 in the cam groove 32 passes when the cam follower pin 43 is in the wide position and the portion 61a through which the cam follower pin 61 in the cam groove 33 passes through the wide position are the axis (Z axis) of the cam cylinder 30. ) In the direction perpendicular to This is because the cam follower pin 43 and the cam follower pin 61 are easily stopped at the wide position.

  Further, in the first portion 36, as shown in FIGS. 2 and 3, the cam grooves 32 and 33 are provided deeper than the thickness of the first material A that is easy to be plated, up to the portion of the second material B that is difficult to be plated. 5, the first portion 36 shown in FIG. 5 is cut only when the conductive portion C is cut at a portion intersecting the cam grooves 32 and 33, and the conductive cam follower pins 43 and 61 are located at this portion. The first portion 36 conducts from the portion 36a into which the cam follower pin 31 is press-fitted to the Z minus end.

  The second portion 37 includes a portion 37 a where the cam follower pin 31 is press-fitted on the outer surface of the cam cylinder 30, a portion 43 b through which the cam follower pin 43 is in the tele position in the cam groove 32, and a cam follower pin in the cam groove 33. It is formed to extend to the Z minus end of the cam cylinder 30 through the portion 61b that passes when 61 is in the tele position.

  Here, the portion 43b through which the cam follower pin 43 in the cam groove 32 passes when in the tele position and the portion 61b through which the cam follower pin 61 in the cam groove 33 passes when in the tele position are also the axis (Z-axis) of the cam cylinder 30. ) In the direction perpendicular to This is also because the cam follower pin 43 and the cam follower pin 61 are easily stopped at the tele position as in the wide position.

  Also in the second portion 37, as in the first portion, the cam grooves 32 and 33 are provided deeper than the thickness of the first material A that is easy to plate and reach the portion of the second material B that is difficult to plate. The second portion 37 shown in FIG. 5 is provided only when the conductive portion C is cut at a portion intersecting the cam grooves 32 and 33 and the conductive cam follower pins 43 and 61 are located at this portion. The second portion 37 conducts from the portion 36a into which the cam follower pin 31 is press-fitted to the Z minus end.

  In the rectilinear cylinder 50, the first material A forms a protruding portion 51 that extends outward in the Z minus direction, and a conductive portion C is formed over the outer periphery of the protruding portion 51, and this conductive portion C is fixed by a contact piece 54. 20 conductive portions C are in contact.

  Further, the third lens group chamber 70 and the CCD base 12 which are focus groups, and the resin shaft 13 which guides the third lens group chamber 70 linearly with respect to the CCD base 12 are also manufactured by two-color molding. As shown in FIGS. 1 to 3, the CCD base 12 has a conductive portion C in a portion where a screw hole for fixing the resin shaft 13 is provided, and a conductive screw 12 a is connected to the FPC 28 in the screw hole. The resin shaft 13 is fixed by being screwed. Further, the resin shaft 13 has a conduction portion C in a portion close to the CCD base 12. The third lens group chamber 70 has a conducting portion C on the Z side surface. On the other hand, a screw hole is also provided on the Y minus side of the CCD base 12, and a conductive guide shaft 71 for guiding the Y minus side of the third lens group chamber 70 is inserted into the hole with the FPC 28 interposed therebetween. It passes through the conducting part C of the three lens group chamber 70 and is fixed to the fixed cylinder 20.

  Next, the operation will be described. First, in the retracted state of FIG. 1, the cam follower pin 31 is not in the second portion 26 or the third portion 27, which is the conduction portion C of the cam groove 22, and therefore the conduction path that continues from the main board 3 to the cam follower pin 31. Is disconnected.

  2, the cam follower pin 31 reaches the second portion 26 shown in FIG. 5, which is the conduction portion C of the cam groove 22, and is guided from the main board 3 to the cam follower pin 31 via the FPC 29. The passage is connected. As shown in FIG. 4, in the cam cylinder 30, the first part 36 extending from the portion 36 a in which the cam follower pin 31 is press-fitted to the Z minus end of the cam cylinder 30 has the cam follower pin 43 in the cam groove 32. Since the cam follower pin 61 is located in the portion 61a in the cam groove 33, the cam follower pin 61 is located in the portion 43a.

  Returning to FIG. 2, the conducting part C at the Z minus end of the cam cylinder 30 contacts the conducting part C of the straight cylinder 50, and the conducting part C continues to the conducting part C of the fixed cylinder 20 by the contact piece 54. The conducting portion C of the fixed cylinder 20 is conducted to the main substrate 3 by the FPC 28 via the screw 21. In the main substrate 3, it is detected that a circuit that is conductive when each cylindrical body in the lens barrel 2 is in the wide state position, and it is determined that the circuit is in the wide end, and the motor is stopped. Therefore, each cylindrical member can be stopped at the designed position.

  3, the cam follower pin 31 reaches the third portion 27 shown in FIG. 5, which is the conduction portion C of the cam groove 22, and continues from the main board 3 to the cam follower pin 31 via the FPC 29. The passage is connected. As shown in FIG. 5, in the cam cylinder 30, the second part 37 extending from the portion 37 a into which the cam follower pin 31 is press-fitted to the Z minus end of the cam cylinder 30 has the cam follower pin 43 in the cam groove 32. Since the cam follower pin 61 is located in the portion 61b in the cam groove 33, the cam follower pin 61 is located in the portion 43b, and is thus conducted to the Z minus end of the cam cylinder 30.

  Returning to FIG. 3, the conducting portion C at the Z minus end of the cam cylinder 30 contacts the conducting portion C of the straight cylinder 50, and the conducting portion C continues to the conducting portion C of the fixed cylinder 20 by the contact piece 54. The conducting portion C of the fixed cylinder 20 is conducted to the main substrate 3 by the FPC 28 via the screw 21. In the main board 3, it is detected that a circuit that conducts when each cylindrical body in the lens barrel 2 is in the tele state position, and it is determined that the circuit is at the tele end, and the motor is stopped. Therefore, each cylindrical member can be stopped at the designed position.

  Further, when the third lens group chamber 70 is moved to a position where the conductive portion of the resin shaft 13 is provided, the FPC 28, the conductive portion C of the CCD base 12, the conductive portion C of the resin shaft 13, and the third lens group chamber 70. The conductive portion C, the conductive guide shaft 71, and the FPC 28 are electrically connected, and the main substrate 3 detects that the third lens group chamber 70 is in a predetermined position.

As described above, this embodiment has the following effects.
(1) In the conventional lens barrel 2, for example, in order to confirm the zoom position, it is necessary to measure the stop position and collate it with the focal length of the design value. However, according to the present embodiment, when the designed wide position or tele position is reached, it can be detected that the circuit that conducts when the wide position or tele position is in the main board 3 is conducted. Therefore, the lens can be easily stopped at the design position.
(2) Conventionally, when the motor is stopped by a pulse of the motor, the stop position may vary due to backlash or backlash, but even in such a case, the cam groove is set so that the focal length does not change. Some flat portions were provided at the 32 wide ends and the tele end. For this reason, an extra space in the circumferential direction of the cam groove 32 is required, and in order to fit in the space, it is necessary to make the inclination of the cam steep, thereby increasing the size of the lens barrel and increasing the driving load. There was a problem of being invited. Also in this embodiment, a flat portion is provided in order to make it easy for the cam follower pin 43 and the cam follower pin 61 to stop at the wide position or the tele position. Therefore, it is not necessary to make the cam tilt steep, the size of the lens barrel can be reduced, and the driving load can be reduced.
(3) Further, the conventional zoom control always stops from a certain direction in consideration of the backlash at the time of direction reversal (for example, when the zoom operation is performed in the retraction direction, the backlash removal operation is performed and the retraction direction is Was stopped). For this reason, the appearance of the operation is poor (returns after going too far), and the zoom time is lost as much as the backlash removal operation. However, according to the present embodiment, since the position of each cylinder can be directly observed, it is not necessary to remove backlash, and the zoom time can be shortened and the appearance of the zoom operation can be improved.
(4) Further, when the third lens group chamber 70 is moved to a position where the conducting portion of the resin shaft 13 is provided, the FPC 28, the conducting portion C of the CCD base 12, the conducting portion C of the resin shaft 13, and the third lens. The conducting portion C of the group chamber 70, the conductive guide shaft 14, and the FPC 28 are conducted, and the main substrate 3 detects that the third lens group chamber 70 is in a predetermined position. Therefore, by setting the position as the reset position, the operating position of the third lens group chamber 70 that is the focus group can be controlled. As a result, the photo interrupter that has been used in the conventional reset position can be eliminated.

(Deformation)
The present invention is not limited to the above-described embodiment, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.
(1) Although the lens barrel has been described in the present embodiment, the present invention is not limited to this, and can be applied to other devices as long as a drive mechanism having two members that move relative to each other is provided.
(2) Although the conductive portion is provided in the flat portion of the cam groove, the present invention is not limited to this. For example, the conductive portion is provided before and after the flat portion, and the cam follower passes through the conductive portion. It is also possible to send a stop signal, start deceleration, and make it easy to stop the cam follower at the flat part. In this case, the flat portion can be further shortened.
(3) In this embodiment, the width of the conductive portion is narrower than the flat portion of the cam groove, but the present invention is not limited to this, and the width of the conductive portion is wider than the flat portion of the cam groove so that the cam follower is conductive. It is also possible to send a stop signal to the motor when it passes through the section, start deceleration, and make it easy to stop the cam follower in the flat section. Also in this case, the flat portion can be further shortened.

  In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited to the embodiment described above.

It is sectional drawing which shows the retracted state in a lens barrel provided with the drive mechanism of 1st Embodiment of this invention. It is sectional drawing which shows the wide state in a lens barrel provided with the drive mechanism of 1st Embodiment of this invention. It is sectional drawing which shows the tele state in a lens barrel provided with the drive mechanism of 1st Embodiment of this invention. It is an expanded view of the inner surface of a fixed cylinder. It is an expanded view of the inner surface of a cam cylinder.

Explanation of symbols

  1: driving mechanism, 20: fixed cylinder, 22: cam groove, 30: cam cylinder, 31: cam follower pin, 32: cam groove, 33: cam groove, 40: first lens group cylinder, 43: cam follower pin, 60: Second lens group chamber, 61: cam follower pin, A: material that is easy to plate, B: material that is difficult to plate, C: conduction part

Claims (5)

A zoom lens drive mechanism,
A cam groove for changing a focal length of the zoom lens by driving a lens constituting the zoom lens in an optical axis direction so as to intersect the cam groove at a wide position and a tele position of the cam groove; A cam cylinder in which metal plating is formed as a conductive portion on the inner peripheral surface;
The electrically conductive follower pins that engage the cam groove, and a moving cylinder moves relative to the cam barrel while moving along the follower pin into the cam groove,
When the follower pin moves in the cam groove and reaches the position where the conductive portion intersects , the conductive portion and the follower pin are electrically connected, so that the position of the movable tube is wide with respect to the cam tube . Or it can be detected that it is in the tele position ,
The drive mechanism characterized in that a portion of the cam groove where the conducting portion intersects is a flat portion extending in a direction perpendicular to the axis of the cam cylinder . The drive mechanism according to claim 1 ,
The conducting portion includes a first conducting portion that intersects the cam groove at a wide position of the cam groove, and a second conducting portion that intersects the cam groove at a tele position of the cam groove, each having a different circuit. When the follower pin moves through the cam groove and reaches the position where the conductive portions intersect, the circuits detect the continuity between the conductive portions and the follower pin , It is possible to determine that the cam cylinder and the movable cylinder are in a predetermined positional relationship. The drive mechanism according to claim 1 or 2 ,
A driving mechanism formed by two-color molding of a material that is easy to plate and a material that is difficult to plate, and by performing metal plating on the surface of the portion that is molded with the material that is easy to plate. A lens barrel comprising the drive mechanism according to any one of claims 1 to 3 . A camera comprising the drive mechanism according to any one of claims 1 to 3 .

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