JP5800550B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel mounted on an imaging apparatus such as a digital camera.

  Some lens barrels, such as digital cameras, perform a focusing operation by moving an image sensor in the optical axis direction with respect to a lens unit. As such a lens barrel, for example, a lens barrel that supports a holding frame that holds an image sensor so as to be movable in the optical axis direction by two guide shafts has been proposed (Patent Document 1).

Japanese Patent Laid-Open No. 7-159622

  However, in Patent Document 1, since the holding frame that holds the image sensor along the two guide axes moves in the optical axis direction, a long space is required in the optical axis direction, and the lens barrel is thin when retracted. It becomes the cause which prevents the conversion.

  Accordingly, an object of the present invention is to provide a mechanism that can reduce the length of the lens barrel in the optical axis direction when retracted to reduce the thickness of the lens barrel.

In order to achieve the above object, a lens barrel according to the present invention includes a lens unit, a cam barrel in which a cam groove for moving the lens unit in the optical axis direction is formed in an inner peripheral portion, and the lens of the cam barrel. An image sensor that photoelectrically converts a subject image that has passed through the lens unit is disposed in the inner periphery of the image plane side of the unit so as to be movable in the optical axis direction as long as it does not protrude from the end surface of the cam cylinder on the image plane side. A holding frame that is disposed between the lens unit and the holding frame, and is provided so as to be rotatable in a state in which the subject side in the optical axis direction is in contact with the cam cylinder, and the driving ring. Drive means for driving, and provided between the drive ring and the holding frame, and converting the rotational movement of the drive ring into movement in the optical axis direction of the holding frame, thereby moving the imaging device in the optical axis direction. Move Conversion means for performing a focusing operation, a biasing member for biasing the cam barrel and the holding frame in a direction of sandwiching the drive ring to each other, when the lens unit is retracted to the retracted position, the holding frame The drive ring is pushed together with the holding frame into the image plane side within the range where the holding frame does not protrude from the end surface on the image plane side of the cam cylinder against the urging force of the urging member in a state where the lens is extended toward the subject side. A holding member, and the holding frame moves in the optical axis direction while holding the imaging element whose inclination adjustment with respect to the optical axis is completed .

  According to the present invention, since the length of the lens barrel in the optical axis direction when retracted can be shortened, the lens barrel can be thinned.

It is sectional drawing in the retracted position of the single focus type lens barrel which is an example of embodiment of this invention. It is sectional drawing in the wide position of the lens-barrel shown in FIG. FIG. 2 is an exploded perspective view of the lens barrel shown in FIG. 1. It is an expanded view of the inner peripheral side of a fixed cam cylinder. It is a disassembled perspective view of an image sensor unit. It is a disassembled perspective view of an image sensor unit, a fixed cam cylinder, and a drive ring. It is the figure which looked at the optical element direction from the image pick-up element unit side to the assembly of an image pick-up element unit, a fixed cam cylinder, and a drive ring. (A) is the perspective view of a drive ring, (b) is the perspective view which looked at the drive ring shown to (a) from the back side. It is a perspective view of a holding frame. It is principal part sectional drawing of the state in which the drive ring is urged | biased by the tension spring to the fixed cam cylinder side. It is a principal part sectional view showing a state where the convex spherical part of the holding frame is in contact with the end face of the face cam part of the drive ring on the imaging element side. It is principal part sectional drawing which shows the state in which the rectilinear guide plate contact | abutted to the convex part of the drive ring in the middle of the retraction operation | movement of a lens barrel. It is principal part sectional drawing which shows the state which the holding frame reached | attained to the end surface of a fixed cam cylinder, and the retraction operation | movement of the lens barrel was completed. (A) is principal part sectional drawing which shows the state which the convex spherical part of a holding frame contact | abuts the surface at the side of an image pick-up element of the face cam part of a drive ring in the imaging | photography state of a lens-barrel. FIG. 6B is a cross-sectional view of the main part showing a state in which the convex spherical portion of the holding frame is in contact with the object side surface of the face cam portion of the drive ring in the retracted state of the lens barrel.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of a single focus lens barrel as an example of an embodiment of the present invention at a retracted position, FIG. 2 is a cross-sectional view of the lens barrel shown in FIG. 1 at a wide position, and FIG. 4 is an exploded perspective view of the lens barrel shown in FIG. 4, and FIG. 4 is a development view of the inner peripheral side of the fixed cam barrel.

  As shown in FIGS. 1 to 3, the lens barrel in this embodiment includes a fixed cam barrel 206, a movable cam barrel 204, a first group barrel 201, a second group barrel 203, an aperture / shutter unit 202, and an imaging device. A unit 100 is provided. The first group barrel 201 holds the lens unit 101, and the second group barrel 203 holds the lens units 102 and 103.

  As shown in FIG. 4, three cam grooves 206a and rectilinear guide grooves 206b are provided on the inner peripheral portion of the fixed cam cylinder 206 at substantially equal intervals in the circumferential direction. A moving cam cylinder 204 is disposed on the inner peripheral side of the fixed cam cylinder 206.

  A follower pin 204 a that is cam-engaged with the cam groove 206 a of the fixed cam cylinder 206 is provided on the outer peripheral portion of the movable cam cylinder 204. In addition, a gear portion (not shown) is provided on the outer peripheral portion of the moving cam cylinder 204, and a driving force is transmitted from a motor (not shown) to the gear section via a gear train, so that the moving cam cylinder 204 has a follower pin. It moves in the optical axis direction while rotating by the cam action of 204a and cam groove 206a.

  Three types of cam grooves (not shown) for moving the first lens barrel 201, the second lens barrel 203, and the aperture / shutter unit 202 in the optical axis direction are provided in the inner peripheral portion of the movable cam barrel 204 in the circumferential direction. Are formed at approximately equal intervals. Further, a rectilinear guide plate 205 is bayonet-coupled to the inner peripheral portion of the movable cam barrel 204 so as to be slidable in the rotational direction with respect to the movable cam barrel 204.

  Three straight guide keys (not shown) are formed on the outer peripheral portion of the straight guide plate 205 at substantially equal intervals in the circumferential direction.

  When the rectilinear guide key is engaged with the rectilinear guide groove 206b of the fixed cam cylinder 206, the rectilinear guide plate 205 is restricted from rotating when moved in the optical axis direction. As a result, when the movable cam barrel 204 rotates and moves in the optical axis direction, the rectilinear guide plate 205 moves linearly in the optical axis direction together with the movable cam barrel 204 in a state where the rotation is restricted.

  Further, the linear guide plate 205 includes two linear guide keys 205a for restricting rotation when the first group barrel 201, the second group barrel 203, and the aperture / shutter unit 202 move in the optical axis direction. Protruding in the direction.

  Here, a follower pin (not shown) provided in each of the first group barrel 201, the second group barrel 203, and the aperture / shutter unit 202 is engaged with a cam groove (not shown) of the movable cam barrel 204. Notch portions (not shown) provided in the first group barrel 201, the second group barrel 203, and the aperture / shutter unit 202 engage with the rectilinear guide key 205 a of the rectilinear guide plate 205.

  When the movable cam barrel 204 rotates and moves in the optical axis direction, each of the first group barrel 201, the second group barrel 203, and the aperture / shutter unit 202 follows the cam groove of the movable cam barrel 204. Move straight in the direction of the optical axis.

  Next, the image sensor unit 100 will be described with reference to FIGS.

  FIG. 5 is an exploded perspective view of the image sensor unit 100, and FIG. 6 is an exploded perspective view of the image sensor unit 100, the fixed cam cylinder 206, and the drive ring 207. FIG. 7 is a view of the assembly of the image sensor unit 100, the fixed cam cylinder 206, and the drive ring 207 as viewed in the optical axis direction from the image sensor unit 100 side. In FIG. 5, in addition to the image sensor unit 100, a fixed cam cylinder 206 and a drive ring 207 are also illustrated.

  As shown in FIGS. 5 and 6, the image sensor unit 100 includes a low-pass filter 302, a holding frame 301 that holds the image sensor 104 and the like.

  The image sensor 104 is constituted by a CCD sensor, a CMOS sensor, or the like, and is integrally fixed to the element plate 304 by adhesion or the like, and photoelectrically converts a subject image that has passed through the lens units 101 to 103.

  The low-pass filter 302 is pressed against the holding frame 301 via an elastic member 303 such as a silicon material, and the hole portion of the element plate 304 is fitted to the shaft portion of the holding frame 301 so as to press the elastic member 303 in this state. The image sensor 104 is positioned.

  Next, in this state, tilt adjustments respectively inserted into the three holes of the element plate 304 against the urging force of the plurality of compression springs 308 disposed between the element plate 304 and the holding frame 301. The adjustment screw 305 is tightened on the holding frame 301.

  As a result, the element plate 304 is fastened to the holding frame 301 to complete the assembly of the image pickup element unit 100, and the drive ring 207 and the image pickup element unit 100 are assembled to the fixed cam cylinder 206 to obtain the state shown in FIG.

  Then, by appropriately adjusting the screwing amounts of the three adjusting screws 305 with respect to the holding frame 301, the inclination of the image sensor 104 with respect to the optical axis can be adjusted.

  Next, a driving mechanism that performs a focusing operation by moving the image sensor unit 100 in the optical axis direction with respect to the lens units 101 to 103 at the time of photographing a subject will be described.

  The focusing operation is performed by the image sensor unit 100, the fixed cam cylinder 206, and the drive ring 207.

  8A is a perspective view of the drive ring 207, FIG. 8B is a perspective view of the drive ring 207 shown in FIG. 8A viewed from the back side, and FIG. 9 is a perspective view of the holding frame 301.

  As shown in FIG. 8, the outer periphery of the drive ring 207 is provided with six convex portions 207a projecting radially outward at substantially equal intervals in the circumferential direction. Is fitted to the inner peripheral surface so as to be slidable in the rotational direction. A gear 207 d is formed on the outer periphery of the drive ring 207.

  On the surface of the drive ring 207 facing the fixed cam tube 206 side, a sliding portion 207b that slides in the rotational direction with respect to the contact surface 206f disposed on the subject side from the end surface of the fixed cam tube 206 is substantially in the circumferential direction. Six places are provided at equal intervals.

  Further, on the radially inner side of the sliding portion 207b of the drive ring 207, six convex portions 206c projecting toward the subject side are provided at substantially equal intervals in the circumferential direction in the same phase as the sliding portion 207b.

  On the other hand, three face cam portions 207e are formed at substantially equal intervals in the circumferential direction on the surface of the drive ring 207 facing the image sensor unit 100 side.

  The face cam portion 207e has an arc shape extending along the circumferential direction of the drive ring 207, and the surface 207e2 on the other end side approaches the image sensor unit 100 side with respect to the surface 207e1 on the one end side in the circumferential direction of the arc shape. Are arranged.

  The surface 207e1 and the surface 207e2 are connected by a slope (see FIG. 14). Here, the surface 207e1 corresponds to an example of the first surface of the present invention, and the surface 207e2 corresponds to an example of the second surface of the present invention.

  As shown in FIG. 9, three hook portions 301a projecting radially outward are provided at substantially equal intervals in the outer circumferential portion of the holding frame 301. Further, flanges 301e and 301f projecting radially outward are provided on the outer peripheral portion of the holding frame 301 so as to be separated from each other by approximately 180 ° in the circumferential direction.

  The flange 301e is formed with a circular hole 301b, and the flange 301f is formed with a long hole 301c that is long in the radial direction of the holding frame 301.

  Furthermore, as shown in FIG. 6, the fixed cam cylinder 206 is provided with a notch 206g, and a photo reflector 309 is fixed to the notch 206g by adhesion or the like.

  The drive ring 207 is also provided with a notch 207f (see FIG. 8), and the mirror plate 310 is fixed to the notch 207f by adhesion or the like.

  In addition, three hook portions 206d protruding outward in the radial direction are provided on the outer peripheral portion of the fixed cam barrel 206 at substantially equal intervals in the circumferential direction.

  A tension spring 307 is hooked on the hook portion 301a of the holding frame 301 and the hook portion 206d of the fixed cam barrel 206, so that the holding frame 301 and the fixed cam barrel 206 are attached to each other in the direction of sandwiching the drive ring 207. Be forced. Here, the tension spring 307 corresponds to an example of the biasing member of the present invention.

  At this time, as shown in FIG. 6, the hole 301b of the flange portion 301e of the holding frame 301 and the long hole portion 301c of the flange portion 301f are respectively inserted into the two shaft portions 206e of the fixed cam cylinder. Accordingly, the holding frame 301 can move in the optical axis direction with respect to the fixed cam barrel 206 in a state where movement and rotation in a direction orthogonal to the optical axis are restricted.

  As shown in FIG. 5, a stepping motor 401 in which a gear 402 is press-fitted into an output shaft is incorporated in the fixed cam cylinder 206. An idle gear 403 that meshes with the gear 402 and the gear 207 d of the drive ring 207 is incorporated in the fixed cam cylinder 206.

  The idle gear 403 is covered with a gear cover 404, and the gear cover 404 is fixed to the flange portion of the stepping motor 401 with screws or the like so as to sandwich the fixed cam cylinder 206.

  When the stepping motor 401 is driven, the rotation of the output shaft of the motor 401 is transmitted from the gear 402 to the gear 207 d via the idle gear 403.

  As a result, the driving ring 207 is urged toward the subject in the optical axis direction (fixed cam cylinder 206 side) by the tension spring 307, so that the six sliding portions 207b are brought into contact with the contact surface 206f of the fixed cam cylinder 206. It rotates while sliding against it.

  FIG. 10 is a cross-sectional view of the main part in a state where the drive ring 207 is biased toward the fixed cam cylinder 206 by the tension spring 307.

  As shown in FIG. 10, the holding frame 301 is formed with three convex spherical portions 301d corresponding to the face cam portion 207e of the drive ring 207 at substantially equal intervals in the circumferential direction. In FIG. 10, the convex spherical portion 301d is in contact with the end face 207e1 of the face cam portion 207e. Here, the convex spherical portion 301d corresponds to an example of the engaging convex portion of the present invention.

  Then, when the drive ring 207 rotates, the holding frame 301 has the convex spherical portion 301d facing the end surface 207e2 side of the face cam portion 207e in a state where the rotation of the holding frame 301 is restricted with respect to the fixed cam barrel 206 as described above. By sliding, the optical axis direction moves to the image sensor 104 side. A focusing operation is performed by the movement of the holding frame 301 in the optical axis direction.

  In this embodiment, as shown in FIG. 11, the holding frame 301 is in a state in which the convex spherical portion 301 d of the holding frame 301 is in contact with the end face 207 e 2 on the imaging element 104 side of the face cam portion 207 e of the drive ring 207. Does not protrude from the end face of the fixed cam cylinder 206.

  Next, the lens barrel extension / retraction operation and the focusing operation will be described.

  When a motor (not shown) is driven in the retracted state of the lens barrel shown in FIG. 1, a driving force is transmitted to the gear portion of the movable cam barrel 204 via the gear train.

  As a result, the movable cam barrel 204 moves in the direction of extending in the optical axis direction while rotating by the cam action of the follower pin 204a and the cam groove 206a of the fixed cam barrel 206. Further, the rectilinear guide plate 205 moves in the optical axis direction together with the movable cam cylinder 204 in a state where the rotation is restricted by the fixed cam cylinder 206.

  When the movable cam barrel 204 is extended in the optical axis direction, the first group barrel 201, the second group barrel 203, and the aperture / shutter unit 202 whose rotation is restricted by the linear guide key 205a are arranged such that the follower pins of the first and second barrels 201, 203 and 202 are movable cam barrels. It moves in the optical axis direction following the cam groove 204. As a result, the lens barrel reaches the wide position (shooting position) as shown in FIG.

  When the lens barrel reaches the wide position, shooting is started and a focusing operation is performed according to the distance of the subject.

  In the initial photographing state, the convex spherical portion 301d of the holding frame 301 is in contact with the surface 207e1 located closest to the subject of the face cam portion 207e of the drive ring 207, as shown in FIG.

  When the stepping motor 401 is driven in this state, as described above, the drive ring 207 is urged toward the subject side in the optical axis direction by the tension spring 307, and the sliding portion 207b is brought into contact with the fixed cam cylinder 206. It rotates clockwise while sliding against the surface 206f.

  Thus, the holding frame 301 moves the optical axis direction toward the image sensor 104 by sliding the slope of the convex spherical portion 301d toward the end surface 207e2 side of the face cam portion 207e until the subject is focused.

  When the focusing operation is completed, the driving of the stepping motor 401 is stopped, and the subject is photographed.

  When shooting is completed and the power is turned off, the holding frame 301 moves in the direction of the optical axis toward the fixed cam cylinder 206 by an operation opposite to the focusing operation described above, and the convex spherical portion 301d of the holding frame 301 is obtained. Contacts the end face 207e1 of the face cam portion 207e of the drive ring 207 (FIG. 10).

  When the holding frame 301 reaches the position shown in FIG. 10, the lens barrel retracting operation is started by an operation reverse to the above-described extending operation.

  Here, during the retraction operation of the lens barrel, the rectilinear guide plate 205 abuts on the convex portion 207c of the drive ring 207 as shown in FIG.

  When the lens barrel is further retracted, the rectilinear guide plate 205 pushes the drive ring 207 together with the holding frame 301 in the direction away from the imaging element 104 side, that is, the fixed cam barrel 206 against the urging force of the tension spring 307. Go.

  When the holding frame 301 reaches the end surface of the fixed cam barrel 206, the retraction operation of the lens barrel is completed, and the retracted state shown in FIG.

  When the drive ring 207 and the holding frame 301 are pushed into the image sensor 104 side, the drive ring 207 and the holding frame 301 are guided in the optical axis direction by the end outer peripheral wall of the fixed cam cylinder 206. Here, the outer peripheral wall of the end portion of the fixed cam cylinder 206 corresponds to an example of the guide portion of the present invention, and the rectilinear guide plate 205 corresponds to an example of the pushing member of the present invention.

  Next, the relationship among the holding frame 301, the drive ring 207, and the fixed cam cylinder 206 during the focusing operation will be described with reference to FIG.

  FIG. 14A shows a main part showing a state in which the convex spherical portion 301d of the holding frame 301 is in contact with the surface 207e2 of the face cam portion 207e of the drive ring 207 on the imaging element 104 side in the photographing state of the lens barrel. It is sectional drawing.

  Here, the amount of movement of the holding ring 301 from the surface 207e1 to the surface 207e2 of the face cam portion 207e of the drive ring 207, that is, the movable range of the holding frame 301 in the optical axis direction during the focusing operation is z.

  FIG. 14B is a cross-sectional view of the main part showing a state in which the convex spherical portion 301d of the holding frame 301 is in contact with the subject-side surface 207e1 of the face cam portion 207e of the drive ring 207 in the retracted state of the lens barrel. It is.

  In the state of FIG. 14B, as described above, the drive ring 207 moves the holding frame 301 until the holding frame 301 reaches the end surface of the fixed cam cylinder 206 against the urging force of the tension spring 307 by the linear guide plate 205. 301 is pushed into the image sensor 104 side.

  The pushing amount at this time is also z. Therefore, the retraction amount of the lens barrel can be increased by z that is the movable range of the holding frame 301 in the optical axis direction during the retracting operation of the lens barrel.

  Next, the focusing operation reset process using the photo reflector 309 on the fixed cam cylinder 206 side and the mirror plate 310 on the drive ring 207 side will be described.

  In the retracted state of the lens barrel, the photo reflector 309 on the fixed cam barrel 206 side and the mirror surface plate 310 on the drive ring 207 are opposed to each other in the radial direction. It is maintained even if it moves in the optical axis direction.

  After the lens barrel feed-out operation is completed, when the drive ring 207 rotates and the mirror plate 310 moves away from the photo reflector 309 in the rotation direction, the photo reflector 309 detects this and enters the reset standby state. A focusing operation is performed.

  When the photographing is completed and the power is turned off, the drive ring 207 rotates in the opposite direction, the mirror plate 310 again faces the photo reflector 309 in the radial direction, and the photo reflector 309 detects this and detects the combination. A reset operation for the focus operation is performed.

  As described above, in the present embodiment, the retracting amount of the lens barrel can be increased by the movable range z of the holding frame 301 in the optical axis direction during the retracting operation of the lens barrel. In addition, since the rotational movement of the drive ring 207 is converted into the movement of the image sensor 104 in the optical axis direction to perform the focusing operation, the image sensor 104 is moved to the optical axis as compared with the case where the image sensor is moved along the screw axis. The space in the optical axis direction of the drive mechanism that moves in the direction can be shortened. Thereby, the length of the lens barrel in the optical axis direction when retracted can be shortened, and the lens barrel can be thinned.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

  For example, in the above embodiment, the case where the present invention is applied to a single focus type lens barrel is illustrated, but the present invention may be applied to a zoom drive type lens barrel.

101-103 Lens unit 104 Image sensor 205 Straight guide plate 206 Fixed cam barrel 207 Drive ring 207e Face cam 301 Holding frame 301d Convex spherical portion 307 Tension spring 401 Stepping motor

Claims (5)

A lens unit;
A cam cylinder having a cam groove formed on an inner peripheral portion for moving the lens unit in the optical axis direction;
The cam cylinder is disposed so as to be movable in the optical axis direction within a range that does not protrude from the end surface of the cam cylinder on the image plane side of the lens unit, and the subject image that has passed through the lens unit is photoelectrically converted. A holding frame for holding an image sensor to be converted;
A drive ring that is disposed between the lens unit and the holding frame and is provided so as to be rotatable in a state in which the subject side in the optical axis direction is in contact with the cam cylinder;
Drive means for driving the drive ring;
Focusing operation is performed between the drive ring and the holding frame, and the rotational movement of the drive ring is converted into movement in the optical axis direction of the holding frame to move the image sensor in the optical axis direction. Conversion means for performing
A biasing member that biases the cam cylinder and the holding frame in a direction to sandwich the drive ring;
When the lens unit is retracted to the retracted position, the drive ring is moved together with the holding frame against the urging force of the urging member while the holding frame is extended toward the subject side. A pushing member that pushes into the image plane side within a range in which the holding frame does not protrude from the end face of
The image sensor is fastened to the holding frame by a plurality of adjustment screws for tilt adjustment via an element plate to which the image sensor is fixed,
The lens barrel according to claim 1, wherein the holding frame moves in the optical axis direction while holding the imaging element whose inclination adjustment with respect to the optical axis is completed by the adjusting screw . The cam barrel, the lens barrel according to claim 1, characterized in that it comprises a guide portion for guiding the drive ring and the holding frame are written to Ri押 by the push member in the optical axis direction.   The conversion means includes a cam portion formed at a plurality of locations at equal intervals in a circumferential direction on a surface of the drive ring facing the holding frame, and formed on the holding frame, respectively. The lens barrel according to claim 1, further comprising an engaging convex portion that engages with a cam.   The cam portion has an arc shape extending along a circumferential direction of the drive ring, and a second surface on the other end side is a side of the holding frame with respect to a first surface on one end side in the circumferential direction of the arc shape. 4. The lens barrel according to claim 3, wherein the lens barrel is disposed close to the first lens body, and the first surface and the second surface are connected by an inclined surface. The holding frame, the when the lens unit is retracted to the retracted position, the most to move to a position out toward the object side, characterized in Rukoto claims 1 to lens barrel according to any one of 4 .

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