JP2015001707A - Lens drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens drive device that enables miniaturization in a linear direction connecting an optical axis of a moving lens to a lead screw.SOLUTION: The lens drive device comprises: lens frames 36 and 48 that are rectilinearly movable along one direction and have lens support holes 39 and 51; retreating recess parts 43 and 55 that are recessedly provided on surfaces of the lens frames; screw rods 70 and 73 that are rotatable around axial lines of the screw rods; nuts 75 and 81 that are threadably engaged with the screw rods, and have a relative movement in an optical axis direction to the lens frames regulated; an engagement part 77 that is formed in the nut, and regulates a rotation around the axial line of the nut; and a loose fitting end part 78 that is formed in the nut, and is loosely fitted into the retreating recess part. An end face of the loose fitting end part on the lens support hole side is constituted by a nut side plane 79 perpendicular to a linear line connecting an optical axis to the axial line, and on a lens support hole side face of an inner face of the retreating recess part, recess part side plane faces 44 and 56 are formed that face the nut side plane face and the linear line direction.

Description

  The present invention relates to a lens driving device for driving a lens that moves straight along an optical axis.

  In recent years, portable electronic devices mainly for photographing such as digital still cameras and digital video cameras, and portable electronic devices having an incidental photographing function such as camera-equipped mobile phones and portable information terminals have been widely used. In this type of portable electronic device, it is widely performed to incorporate an imaging unit having a configuration in which an imaging element and an imaging optical system for guiding imaging light to the imaging element are housed in a hollow housing.

As a conventional technique of the imaging unit, for example, there is one disclosed in Patent Document 1.
The imaging unit includes a hollow case, an imaging optical system having optical elements such as lenses and prisms provided in the case, an imaging element for imaging (receiving) imaging light emitted from the imaging optical system, and imaging A lens driving device that moves the moving lens of the optical system along the optical axis of the moving lens.

The lens driving device includes a guide rod fixed to the inner surface of the case, a lens frame that supports the moving lens and is slidably supported by the guide rod, and a screw rod that is parallel to the guide rod and rotatable about its own axis. A motor having an output rotation shaft) and a nut screwed to the screw rod. The nut is supported on the lens frame in a state where the rotation around the axis of the screw rod and the relative movement in the optical axis direction with respect to the lens frame are restricted.
In this imaging unit, when the screw rod is rotated by the driving force of the motor, the nut whose rotation is restricted moves forward and backward along the screw rod and the guide rod together with the lens frame, and the moving lens moves forward and backward to perform a zooming operation. .

JP 2012-93729 A

In recent years, since the image pickup unit has been downsized, there is an increasing demand for downsizing the lens driving device, and in particular, there is a strong demand for downsizing in the linear direction connecting the optical axis of the moving lens and the lead screw.
However, it is difficult for the lens driving device of Patent Document 1 to meet this requirement.

  An object of this invention is to provide the lens drive device which can be reduced in size in the linear direction which connects the optical axis of a moving lens, and a lead screw.

  The lens driving device according to the present invention includes a lens frame that is linearly movable along one direction and has a lens support hole, and is recessed on a surface of a portion of the lens frame that is positioned on the outer peripheral side of the lens support hole. A relief recess that is recessed toward the lens support hole and at least one end of the one direction is closed; a movable lens that is fixed to the lens support hole and has its optical axis parallel to the one direction; A screw rod that is rotatable about its own axis parallel to the optical axis of the moving lens; a nut that is screwed with the screw rod and that is restricted from relative movement in the optical axis direction with respect to the lens frame; An engagement part that regulates rotation of the nut around the axis by contacting the lens frame outside the relief recess formed on the nut, and the screw formed on the nut. A loose fitting end portion that is positioned closer to the moving lens than the rod and loosely fits in the relief recess, and the end surface of the loose fitting end portion on the lens support hole side is defined by the optical axis and the axis. A recess side plane that is opposed to the nut side plane in the linear direction on the side surface of the lens support hole on the inner surface of the escape recess. Yes.

When viewed in a direction perpendicular to the optical axis and the straight line in a state where the loose fitting end is loosely fitted in the relief recess on the outer surface of the nut, the screw rod side is more than the nut side plane. A corner portion that is formed between the end surface in the optical axis direction of the inner surface of the escape recess and the recess-side flat surface is opposed to the corner-opposing portion. You may comprise by a structural surface.
In this case, a nut receiving recess into which the nut is inserted is formed on the surface of the lens frame on the outer peripheral side of the lens support hole, and both end surfaces of the nut in the optical axis direction are the optical axis. A pair of lens frame contact surfaces that are orthogonal to the inner surface of the nut receiving recess, and the entire nut side plane is on the other lens frame contact surface side of the one lens frame contact surface. And the optical axis direction dimension of the nut side plane is shorter than the optical axis direction interval between the pair of lens frame contact surfaces, and the corner facing portion is the one lens frame contact The nut-side plane when viewed in a direction perpendicular to the optical axis and the straight line in a state where the surface and the nut-side plane are connected and the loose-fit end portion is loosely fitted in the relief recess In a plane inclined toward the screw rod side It may be.

  A rotation-preventing recess is formed on the surface of a portion of the lens frame that is located on the outer peripheral side of the lens support hole, the position being different from the escape recess, and the engagement portion of the nut is connected to the rotation-stopping It is good also as a convex part for rotation prevention fitted to the concave part for operation.

In the lens driving device of the present invention, the loose fitting end portion formed in the nut is loosely fitted in the relief recess formed in the lens frame. Furthermore, the end surface of the loose fitting end portion on the lens support hole side is constituted by a nut side plane orthogonal to the straight line connecting the optical axis of the moving lens and the axis of the screw rod, and the side surface of the lens support hole on the inner surface of the escape recess In addition, a recess side plane is formed opposite to the nut side plane in the linear direction.
Therefore, since the screw rod can be moved closer to the optical axis side of the moving lens as compared with the conventional lens driving device, the lens driving device of the present invention has the moving lens compared with the conventional lens driving device. It is possible to reduce the size in the linear direction connecting the optical axis of the lead and the lead screw.
In addition, the lens frame has a relief recess that is shorter in one direction (the moving direction of the lens frame) than the entire lens frame (at least one end in one direction is closed). Thickness of the part between the lens support hole surface and the part of the lens frame located on the outer peripheral side compared to the case where the relief recess is formed over the entire dimension (both ends are open). Can be thickened. Therefore, it is possible to increase the mechanical strength of the periphery of the lens frame escape recess.

It is the perspective view seen from the front diagonal upper part of the imaging unit of one embodiment of the present invention. It is the disassembled perspective view seen from the front diagonal upper direction of the imaging unit. It is the perspective view seen from the front diagonal upper direction of the image pick-up unit which omits the 1st lens group holder, the image sensor, and the main part case. It is a front view of a bending optical system. It is the perspective view seen from the diagonally lower left of the second group lens frame, the second group side nut, the third group lens frame, and the third group side nut. It is the perspective view seen from the diagonally right rear of the 2nd group side nut. It is a left view of the 2nd group side nut. It is a rear view of a 2nd group side nut. It is sectional drawing which follows the IX-IX arrow line of FIG. It is sectional drawing which follows the XX arrow line of FIG. It is sectional drawing which follows the XI-XI arrow line of FIG.9 and FIG.10. It is an enlarged view of the XII part of FIG. It is an enlarged view of the XIII part of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, front and rear, left and right, and up and down directions are based on arrow directions described in the drawings.
The imaging unit 10 of the present embodiment includes a first lens group block 15, a main body case 20, an imaging element 26, and a lens driving device 30 as large components.

  The first lens group block 15 includes a first lens group holder 16 made of synthetic resin. A lens support hole 17 is formed in the upper part of the first lens group holder 16, and a prism holding hole (not shown) communicating with the lens support hole 17 is formed in the lower part of the first lens group holder 16. The lens support hole 17 has a planar shape (cross-sectional shape, substantially D-shape) obtained by cutting a circle along a string connecting two points of the circle. A lens L1 having the same planar shape (cross-sectional shape) as the lens support hole 17 and having an optical axis extending in the vertical direction is fitted and fixed in the lens support hole 17. On the other hand, the prism holding hole has an incident surface P1-a composed of a plane orthogonal to the vertical direction (the optical axis of the lens L1) and an exit surface P1-b composed of a plane orthogonal to the horizontal direction. The first prism P1 provided is fitted and fixed.

The main body case 20 made of synthetic resin is a hollow member having an open bottom surface. A mounting recess 21 is formed in the upper portion of the left side portion of the main body case 20, and a prism escape hole 22 communicating with the mounting recess 21 is formed in the lower portion of the left side portion of the main body case 20. Further, the main body case 20 is provided with a lens support hole 23 located on the right side of the mounting recess 21 and communicating with the internal space of the main body case 20, and the lens L2 and the lens L3 are supported in the lens support hole 23. .
A first lens group block 15 (first lens group holder 16) is fitted and fixed to the mounting recess 21 of the main body case 20. When the first lens group block 15 (first lens group holder 16) is fixed to the mounting recess 21, the lower portion of the first prism P1 is positioned in the prism escape hole 22. Further, the lenses L2 and L3 are located on the right side of the emission surface P1-b of the first prism P1, and the emission surface P1-b is orthogonal to the optical axis extending in the left-right direction of the lenses L2 and L3.
The lens L1 and the first prism P1, and the lens L2 and the lens L3 of the first lens group block 15 are components of the first lens group LG1.

On the upper surface of the right side portion of the main body case 20, a prism mounting recess 24 that communicates with the internal space of the main body case 20 is recessed downward. A second prism P2 is fitted and fixed in the prism mounting recess 24. The second prism P2 includes an incident surface P2-a that is a plane orthogonal to the left-right direction and an output surface P2-b that is a plane orthogonal to the vertical direction.
Furthermore, the main body case 20 is provided with a lens support hole (not shown) located on the left side of the prism mounting recess 24 and communicating with the internal space of the main body case 20, and a lens L6 is supported in the lens support hole. . The optical axis extending in the left-right direction of the lens L6 coincides with the optical axes of the lenses L2 and L3, and is orthogonal to the incident surface P2-a of the second prism P2.
An imaging device 26 having an imaging surface on the lower surface is fixed to the upper surface of the right side portion of the main body case 20. Further, a cover glass (not shown) is integrally fixed to the lower surface (imaging surface) of the image sensor 26. The imaging surface (and the cover glass) of the imaging element 26 face each other in the vertical direction while being parallel to the emission surface P2-b of the second prism P2.

Next, the detailed structure of the lens driving device 30 will be described.
A first guide rod 32 and a second guide rod 34 having a circular cross section that extend linearly in the left-right direction are disposed in the internal space of the main body case 20. A right end support portion (not shown) is formed in a portion located on the right side of the central portion in the longitudinal direction of the main body case 20, and a left end support portion (in the portion located on the left side of the central portion in the longitudinal direction of the main body case 20). (Not shown) is formed. The right end portions of the first guide rod 32 and the second guide rod 34 are supported by the right end support portion in a fixed state, and the left end portions of the first guide rod 32 and the second guide rod 34 are fixed to the left end support portion. It is supported by.

The second guide rod 34 is slidably fitted with an insertion hole 37 penetrating the front portion of the second group lens frame 36 (lens frame) made of synthetic resin in the left-right direction. An insertion hole 38 that penetrates the rear portion of the second group lens frame 36 in the left-right direction is slidably fitted. Therefore, the second group lens frame 36 is not rotatable relative to the first guide rod 32 and the second guide rod 34 and is slidable in the left-right direction (optical axis direction) along the first guide rod 32 and the second guide rod 34. It is. A lens L4 (second lens group LG2) (moving lens) is fitted and fixed in a lens support hole 39 that penetrates the center of the second group lens frame 36 in the left-right direction. The side surface shape of the lens support hole 39 and the lens L4 is a shape in which a part (lower part) of a circle centering on the optical axis extending in the left-right direction of the lens L4 is cut along a string connecting the two points. (Substantially D-shaped). The optical axis of the lens L4 coincides with the optical axes of the lenses L2, L3 and L6.
A nut receiving recess 41 that is recessed upward is provided in a portion of the lower surface of the front end portion of the second group lens frame 36 excluding the left and right side portions. As illustrated, the side shape of the upper portion of the nut receiving recess 41 is substantially semicircular, and the left and right ends and the front end of the nut receiving recess 41 are open. Further, a rotation-preventing recess 42 is provided upward on the upper end surface of the inner surface of the nut receiving recess 41 (see FIGS. 5 and 9). The left and right widths of the rotation stopper recess 42 are the same as the left and right widths of the nut receiving recess 41, and the left and right sides of the rotation stopper recess 42 are closed by walls (a part of the second group lens frame 36). Further, an escape recess 43 is provided on the rear surface of the inner surface of the nut receiving recess 41, which is independent from the recess 42 for rotation stop (different in position). As shown in FIG. 9, the rear part of the inner surface of the escape recess 43 is a recess-side plane composed of a plane inclined with respect to the vertical direction (when viewed in the optical axis direction of the lenses L2, L3, L4, and L6). 44. Further, as shown in FIG. 12, corners between the left and right end portions of the inner surface of the escape recess 43 and the recess-side plane 44 are located along the plane where the recess-side plane 44 is located from above (strictly speaking, the lens L2 , L3, L4, and L6 and a straight line (part of the arrow in FIG. 9) connecting the axis of the first screw rod 70 described later and a direction perpendicular to the optical axis. The corner portion constituting surface 45 is formed of a curved surface that is inclined forward (positioned forward) with respect to the concave portion side plane 44. The left and right widths of the escape recesses 43 are shorter than the left and right widths of the second group lens frame 36, and the left and right sides of the escape recesses 43 are blocked by walls (a part of the second group lens frame 36).

The first guide rod 32 is slidably fitted with an insertion hole 49 penetrating the rear portion of the third group lens frame 48 (lens frame) made of synthetic resin in the left-right direction. A rotation stop groove 50 formed in the front portion of the group lens frame 48 is slidably engaged. The anti-rotation groove 50 is formed by a recess having a substantially U-shaped cross section and an opening at the front end. Since the rotation stop groove 50 engages with the second guide rod 34 in this way, the rotation of the third group lens frame 48 around the first guide rod 32 is restricted, and therefore the third group lens frame 48 is not connected to the first guide rod 32. 32 and the second guide rod 34 are slidable in the left-right direction (optical axis direction). A lens L5 (third lens group LG3) (moving lens) is fitted and fixed in a lens support hole 51 that penetrates the center of the third group lens frame 48 in the left-right direction. The side surface shape of the lens support hole 51 and the lens L5 is a shape obtained by cutting a part (lower part) of a circle centering on the optical axis extending in the left-right direction of the lens L5 along a string connecting the two points. (Substantially D-shaped). The optical axis of the lens L5 coincides with the optical axes of the lenses L2, L3, L4, and L6.
A nut receiving recess 53 that is recessed upward is formed in a portion of the lower surface of the rear end portion of the third group lens frame 48 except for the left and right side portions. As illustrated, the side shape of the upper portion of the nut receiving recess 53 is substantially semicircular, and the left and right ends and the rear end of the nut receiving recess 53 are open. Further, the upper end surface of the inner surface of the nut receiving recess 53 is provided with an anti-rotation recess 54 (the same shape as the anti-rotation recess 42 of the second group lens frame 36) upward (see FIGS. 5 and 10). The left and right widths of the rotation stopper recess 54 are the same as the left and right widths of the nut receiving recess 53, and the left and right sides of the rotation stopper recess 54 are closed by walls (a part of the third group lens frame 48). Further, an escape recess 55 that is independent of the rotation stopper recess 54 (different in position) is provided in front of the inner surface of the nut receiving recess 53. As shown in FIG. 10, the front portion of the inner surface of the escape recess 55 is a flat surface that is inclined with respect to the vertical direction when viewed from the side (when viewed in the optical axis direction of the lenses L2, L3, L4, L5, and L6). The recess side plane 56 is used. Further, as shown in FIG. 13, the corner between the right end portion of the inner surface of the escape recess 55 and the recess side plane 56 is from above (strictly speaking, the lens L2, When looking at a straight line (a part of the arrow in FIG. 10) connecting the optical axes of L3, L4, L5, and L6 and the axis of the second screw rod 73 described later (a direction perpendicular to the optical axis). It is comprised by the corner | angular part structure surface 57 which consists of a curved surface which inclines to the back side with respect to the recessed part side plane 56 (located behind). The left and right widths of the escape recess 55 are shorter than the left and right widths of the third group lens frame 48, and the right side of the escape recess 55 is blocked by a wall (a part of the third group lens frame 48).

The lens driving device 30 further includes a motor unit 60.
The motor unit 60 includes a bottom plate 62, a first motor 68, a second motor 71, a second group side nut 75 (nut), and a third group side nut 81 (nut). A pair of front and rear motor brackets 63 and 64 are integrally projected at the right end of the bottom plate 62 having a planar shape substantially the same as that of the main body case 20, and a pair of front and rear screw rods are supported on the left side of the bottom plate 62. Brackets 65, 66 are integrally projected.
The motor main body 69 of the first motor 68 is supported in a fixed state on the motor bracket 63. The first motor 68 extends linearly from the motor body 69 toward the left side (parallel to the optical axes of the lenses L4 and L5) and has a metal first screw rod 70 (screw rod) having an external thread groove on the outer peripheral surface. It has. The tip of the first screw rod 70 is rotatably supported by a screw rod support bracket 65. The first screw rod 70 rotates in the forward direction around its own axis when the rotation drive unit provided in the motor body 69 rotates in the forward direction, and the first screw rod 70 reverses when the rotation drive unit rotates in the reverse direction. Rotate in the direction.
A motor main body 72 of the second motor 71 is supported in a fixed state on the motor bracket 64. The second motor 71 extends linearly from the motor body 72 toward the left side (parallel to the optical axes of the lenses L4 and L5) and has a metal second screw rod 73 (screw rod) having an external thread groove on the outer peripheral surface. It has. The tip of the second screw rod 73 is rotatably supported by a screw rod support bracket 66. When the rotation drive unit provided in the motor main body 72 rotates in the forward direction, the second screw rod 73 rotates in the forward direction around its own axis, and when the rotation drive unit rotates in the reverse direction, the second screw rod 73 is reversed. Rotate in the direction.

The first screw rod 70 is screwed with a female screw hole 76 penetrating in the left-right direction through the central portion of the second group side nut 75 that is a left-right symmetric (not necessarily left-right symmetric) member made of synthetic resin. . The second group side nut 75 includes a nut body 75a having a substantially circular shape when viewed from the side, and a rotation-preventing convex portion 77 (engagement portion) projects upward from the upper portion of the nut body 75a. Further, a loose fitting end 78 is formed at the rear end of the nut body 75a. The rear end surface of the loose fitting end portion 78 is formed by a nut-side plane 79 that is a plane inclined with respect to the vertical direction when viewed from the side (when viewed in the optical axis direction of the lenses L2, L3, L4, L5, and L6). It is configured. On both left and right end surfaces of the nut main body 75a, lens frame contact surfaces 75b made of a plane positioned in front of the loose fitting end portion 78 and orthogonal to the optical axes of the lenses L2, L3, L4, L5, and L6 are provided. It is formed. As is apparent from FIGS. 8 and 12, the optical axis direction dimension (left-right dimension) of the nut side plane 79 is shorter than the optical axis direction interval (left-right distance) between the pair of lens frame contact surfaces 75b. The entire nut side plane 79 is located on the right side of the left lens frame contact surface 75b and on the left side of the right lens frame contact surface 75b. Further, as shown in FIG. 12, the left and right end portions of the loose fitting end portion 78 connect the nut side plane 79 and the left and right lens frame contact surfaces 75b, and the lenses L2, L3, L4, L5, and L6. A straight line connecting the optical axis and the axis of the first screw rod 70 (a part of the arrow in FIG. 9) and the front side with respect to the nut side plane 79 when viewed in a direction perpendicular to the optical axis ( Each of them is constituted by a corner facing portion 80 composed of a plane located in front.
The second screw rod 73 is attached with a third group side nut 81 which is a symmetrical member made of synthetic resin. The third group side nut 81 is a member that is symmetrical with the second group side nut 75 in the front-rear direction. The nut main body 75a, the lens frame contact surface 75b, the female screw hole 76, the rotation preventing convex portion 77, the loose fitting end portion 78, and the nut side plane. 79 and the corner | angular part opposing part 80 are comprised. The third group side nut 81 is attached to the second screw rod 73 by screwing the female screw hole 76 into the second screw rod 73.

The lens driving device 30 includes a second group side nut of the motor unit 60 with respect to the second group lens frame 36 and the third group lens frame 48 supported by the main body case 20 via the first guide rod 32 and the second guide rod 34. 75 and the third group side nut 81 are assembled to each other. Specifically, the left and right positions of the second group side nut 75 and the third group side nut 81 with the rotation stopper convex portion 77 facing upward are shifted from each other, and the second group lens frame 36 (nut receiving recess 41) and the third group are arranged. The left and right intervals of the lens frame 48 (nut receiving recess 53) are made to coincide with the left and right intervals of the rotation-preventing convex portion 77 of the second group side nut 75 and the right and left interval of the rotation stopping convex portion 77 of the third group side nut 81. 60, the main body case 20 is covered from above, and the main body case 20 and the bottom plate 62 are fixed to each other by screws or the like.
Then, the second group side nut 75 enters the nut receiving recess 41 of the second group lens frame 36 from below. More specifically, the rotation preventing convex portion 77 of the second group side nut 75 is fitted to the rotation stopping concave portion 42 of the second group lens frame 36, and the loose fitting end portion 78 of the second group side nut 75 is 2. The loose fitting 43 of the group lens frame 36 is loosely fitted, and the nut main body 75a of the second group side nut 75 is relatively movable with respect to the nut receiving recess 41 in a plane perpendicular to the left-right direction by a small amount. Loose fit. Similarly, the third group side nut 81 enters the nut receiving recess 53 of the third group lens frame 48 from below. That is, the rotation preventing convex portion 77 of the third group side nut 81 is fitted into the rotation stopping concave portion 54 of the third group lens frame 48, and the loose fitting end portion 78 of the third group side nut 81 is fitted to the third group lens frame 48. The nut main body 75a of the third group side nut 81 is loosely fitted to the nut receiving recess 53 so as to be relatively movable in a plane perpendicular to the left-right direction.
When the second group side nut 75 is connected to the nut receiving recess 41 of the second group lens frame 36 in this way, both front and rear surfaces of the rotation stopper recess 42 and both front and rear surfaces of the rotation stopper projection 77 are shown in FIG. Therefore, the relative rotation around the first screw rod 70 with respect to the rotation stopper recess 42 of the rotation stopper protrusion 77 is substantially restricted. Also, as shown in FIG. 12, the left and right lens frame contact surfaces 75b of the nut body 75a of the second group side nut 75 are in contact with the left side surface and the right side surface of the front end (inner surface) of the nut receiving recess 41, respectively. The relative movement of the second group lens frame 36 and the second group side nut 75 in the left-right direction (optical axis direction) is restricted. Further, as shown in FIG. 9, when viewed from the side (when viewed in the optical axis direction of the lenses L 2, L 3, L 4, L 5, and L 6), the recess side plane 44 of the escape recess 43 and the nut of the second group side nut 75. The side planes 79 face each other while being parallel (or substantially parallel) (the recess side plane 44 and the nut side plane 79 are not in contact), and the recess side plane 44 and the nut side plane 79 are lenses L2, L3, L4, L5. And perpendicular to a straight line (a part of the arrow line in FIG. 9) connecting the optical axis of L6 and the axis of the first screw rod 70. Further, as shown in FIG. 12, the left corner portion constituting surface 45 of the recess side plane 44 and the left corner facing portion 80 of the loose fitting end portion 78 face each other (the corner constituting surface 45 and the corner facing portion 80). Is not contacted), and the right corner forming surface 45 of the recess side plane 44 and the right corner facing portion 80 of the loose fitting end 78 are opposed to each other (the corner forming surface 45 and the corner facing portion 80 are non-contact). contact).
Similarly, as shown in FIG. 10, since the clearance between the front and rear surfaces of the rotation stopper recess 54 and the front and rear surfaces of the rotation stopper projection 77 of the third group side nut 81 is substantially zero (because of contact), the rotation The relative rotation around the second screw rod 73 with respect to the rotation stopper recess 54 of the stopper projection 77 is substantially restricted. Further, as shown in FIG. 13, the left and right lens frame contact surfaces 75b of the nut body 75a of the third group side nut 81 are in contact with the left side surface and the right side surface of the rear end portion (the inner surface) of the nut receiving recess 53, respectively. The relative movement in the left-right direction of the third group lens frame 48 and the third group side nut 81 is restricted. Further, as shown in FIG. 10, when viewed from the side (when viewed in the optical axis direction of the lenses L 2, L 3, L 4, L 5, and L 6), the recess side plane 56 of the escape recess 55 and the nut of the third group side nut 81. The side planes 79 face each other while being parallel (or substantially parallel) (the recess side plane 56 and the nut side plane 79 are not in contact), and the recess side plane 56 and the nut side plane 79 are lenses L2, L3, L4, L5. And perpendicular to a straight line (a part of the arrow line in FIG. 10) connecting the optical axis of L6 and the axis of the second screw rod 73. Further, as shown in FIG. 13, the corner forming surface 57 on the right side of the recess side plane 56 and the corner facing portion 80 on the right side of the loose fitting end portion 78 face each other (the corner forming surface 57 and the corner facing portion 80). Is non-contact).

When the imaging unit 10 is assembled by combining the main body case 20 and the lens driving device 30, the first lens group LG1 (the lens L1, the first prism P1, the lens L2, and the lens L3), the second lens group LG2 (the lens L4). ), The third lens group LG3 (lens L5) and the second prism P2 constitute an imaging optical system (bending optical system) (see FIG. 4).
Further, when the first screw rod 70 is rotated forward and backward about its axis by operating the first motor 68, the first screw rod 70 is screwed and the rotation of the second group lens frame 36 is restricted. Since the second group side nut 75 moves back and forth in the left-right direction along the first screw rod 70, the second group lens frame 36 (lens L4), in which the relative movement in the left and right direction with respect to the second group side nut 75 is restricted, is at the tele end position ( It moves linearly in the left-right direction along the first guide rod 32, the second guide rod 34, and the first screw rod 70 between a wide end position (not shown) and a wide end position (not shown). Similarly, when the second screw rod 73 is rotated forward and backward around its axis by operating the second motor 71, the second screw rod 73 is screwed together and the rotation is restricted with respect to the third group lens frame 48. Since the third group side nut 81 moves back and forth in the left and right direction along the second screw rod 73, the third group lens frame 48 (lens L5), in which the relative movement in the left and right direction with respect to the third group side nut 81 is restricted, is at the tele end position. It moves linearly in the left-right direction along the first guide rod 32, the second guide rod 34, and the second screw rod 73 between a wide end position (not shown) and a wide end position (not shown).

When the imaging unit 10 is directed to a subject positioned above, reflected light (photographing light) of the subject traveling downward passes through the lens L1 and then enters the first prism P1 from the incident surface P1-a. The light is reflected toward the right side while the traveling direction is converted by 90 ° toward the emission surface P1-b by the inner surface (first reflection surface) of one prism P1. Further, the reflected light that has exited the exit surface P1-b passes through the lenses L2 to L6, and then enters the inside of the second prism P2 from the entrance surface P2-a, and then enters the inner surface (second reflection surface) of the second prism P2. ) Is reflected upward while the traveling direction is converted by 90 ° to the exit surface P2-b side, and (taken through the cover glass) is imaged (received) by the imaging surface of the imaging element 26.
Further, the second lens group LG2 (lens L4) and the third lens group LG3 (lens L5) are advanced and retracted along the first guide rod 32 and the second guide rod 34 using the first motor 68 and the second motor 71. Thus, if the image pickup optical system is zoomed and focused, the subject image can be picked up in a zoomed and focused state.

In the lens driving device 30 (imaging unit 10) of the present embodiment, the loose fitting end portion 78 formed on the second group side nut 75 is loosely fitted in the escape recess 43 formed on the second group lens frame 36. Further, the end surface of the loose fitting end 78 on the lens support hole 39 side is constituted by a nut side plane 79 orthogonal to a straight line connecting the optical axis of the second lens group LG2 (lens L4) and the axis of the first screw rod 70. A portion of the inner surface of the escape recess 43 facing the nut side plane 79 in the linear direction is constituted by a recess side plane 44 parallel to the nut side plane 79. Therefore, the first screw rod 70 can be moved closer to the optical axis side of the lens L4 (LG2) (compared with the conventional lens driving device). Similarly, a loose fitting end portion 78 formed in the third group side nut 81 is loosely fitted in the escape recess 55 formed in the third group lens frame 48. Further, the end surface of the loose fitting end portion 78 on the lens support hole 51 side is constituted by a nut side plane 79 orthogonal to a straight line connecting the optical axis of the third lens group LG3 (lens L5) and the axis line of the second screw rod 73. A portion of the inner surface of the escape recess 55 facing the nut side plane 79 in the linear direction is constituted by a recess side plane 56 parallel to the nut side plane 79. Therefore, the second screw rod 73 can be moved closer to the optical axis side of the lens L5 (LG3) (compared to the conventional lens driving device).
Therefore, the lens driving device 30 (imaging unit 10) of the present embodiment can be downsized in the front-rear direction compared to the conventional lens driving device.

In the present embodiment, the corner facing portions 80 are formed at the left and right end portions of the loose fitting end portion 78 of the second group side nut 75. Therefore, the corners on the rear side (lens L4 side) of the left and right ends of the escape recess 43 of the second group lens frame 36 are connected to the straight line connecting the optical axis and the axis of the first screw rod 70 and the optical axis. The first screw rod 70 side rather than the recess side plane 44 when viewed from a direction orthogonal to the straight line and the optical axis, rather than forming a right angle when viewed from a direction orthogonal to the straight line. It is possible to make it the corner | angular part formation surface 45 located in. Therefore, compared with the case where the corner portion of the escape recess 43 has a right angle, the thickness of the portion located between the lens support hole 39 of the second group lens frame 36 and the corner portion can be increased. In addition, the second lens group frame 36 is formed with a relief recess 43 having a lateral dimension shorter than the entire left and right width of the second lens group frame 36 (both left and right ends are blocked by walls). Compared with the case where the relief recess is formed over the entire left and right width (both left and right ends are open), the thickness of the portion between the lens support hole 39 and the nut receiving recess 41 of the second group lens frame 36 is thicker. ing. Accordingly, it is possible to increase the mechanical strength of the periphery of the escape recess 43 of the second group lens frame 36.
Similarly, by forming the corner facing portion 80 at the right end portion of the loose fitting end portion 78 of the third group side nut 81, the front corner portion of the right end of the escape recess 55 of the third group lens frame 48 is Rather than forming a right angle when viewed from the direction orthogonal to the straight line and the optical axis connecting the optical axis and the axis of the second screw rod 73, the straight line and the optical axis are not formed. When viewed from the orthogonal direction, the corner portion constituting surface 57 can be located on the second screw rod 73 side with respect to the recessed portion side plane 56. Therefore, compared with the case where the corner is a right angle, the thickness of the portion located between the lens support hole 51 of the third group lens frame 48 and the corner can be increased. In addition, the third lens group frame 48 is provided with a relief recess 55 in the third lens group frame 48 that has a lateral dimension shorter than the entire left and right width of the entire third lens group frame 48 (the right end is closed by a wall). Compared with the case where a relief recess is formed over the entire left and right width of 48 (both left and right ends are open), the thickness of the portion of the third group lens frame 48 between the lens support hole 51 and the nut receiving recess 53 is thicker. It has become. Accordingly, it is possible to increase the mechanical strength of the periphery of the escape recess 55 of the third group lens frame 48.
Furthermore, a pair of left and right corner facing portions 80 that face the left and right corner configuration surfaces 45 in a non-contact state are formed on the loose fitting end portion 78 of the second group side nut 75, and the third group side nut 81 is loosely fitted. A corner-facing portion 80 is formed on the end portion 78 so as to face the right-side corner configuration surface 57 in a non-contact state. Therefore, although the corner portion forming surface 45 is formed in the recess 43 for escape and the corner portion forming surface 57 is formed in the third group lens frame 48, the first screw rod 70 is compared with the conventional lens driving device. It is possible to bring the lens L4 (LG2) closer to the optical axis and move the second screw rod 73 closer to the optical axis of the lens L5 (LG3).

Although the present invention has been described using the present embodiment, the present invention can be implemented with various modifications.
For example, the first prism P1 and the second prism P2 of the imaging unit 10 may be replaced with mirrors.
Further, the prism included in the imaging optical system (bending optical system) of the imaging unit 10 may be only the first prism P1, or the first prism P1, the second prism P2, and the mirror may be omitted from the imaging optical system ( It can be changed to an imaging optical system that is not a bending optical system).

The lens driving device 30 may be applied to an optical device other than the imaging unit (including a guide rod and a screw rod) different from the imaging unit 10 or an imaging unit including the guide rod and the screw rod.
Further, one of the second group lens frame 36 (lens L4) and the third group lens frame 48 (lens L5) is omitted, or different from the second group lens frame 36 (lens L4) and the third group lens frame 48 (lens L5). A moving lens frame (moving lens) may be provided, and the present invention may be applied between the moving lens frame and the screw rod.
Moreover, you may comprise the corner | angular part structure surface 45 and the corner | angular part structure surface 57 by a plane instead of a curved surface.
Further, one lens frame contact surface 75b of the second group side nut 75 or the third group side nut 81 and the nut side plane 79 may be directly connected in an orthogonal state (even if one corner facing portion 80 is omitted). Good).

DESCRIPTION OF SYMBOLS 10 Image pickup unit 15 1st lens group block 16 1st lens group holder 17 Lens support hole 20 Main body case 21 Mounting recessed part 22 Prism escape hole 23 Lens support hole 24 Prism mounting recessed part 26 Imaging element 30 Lens drive device 32 1st Guide rod 34 Second guide rod 36 2 group lens frame (lens frame)
37 38 Insertion hole 39 Lens support hole 41 Nut receiving recess 42 Rotation stop recess 43 Relief recess 44 Recess side plane 45 Corner forming surface 48 Third lens group frame (lens frame)
49 Insertion hole 50 Anti-rotation groove 51 Lens support hole 53 Nut receiving recess 54 Anti-rotation recess 55 Relief recess 56 Recess side flat surface 57 Corner surface 60 Motor unit 62 Bottom plate 63 64 Motor bracket 65 66 Screw rod support bracket 68 First motor 69 Motor body 70 First screw rod (screw rod)
71 Second motor 72 Motor body 73 Second screw rod (screw rod)
75 Second group side nut (nut)
75a Nut body 75b Lens frame abutting surface 76 Female screw hole 77 Anti-rotation convex part (engagement part)
78 Free fitting end portion 79 Nut side plane 80 Corner portion facing portion 81 Third group side nut (nut)
L1 Lens L2 Lens L3 Lens L4 Lens (moving lens)
L5 lens (moving lens)
L6 lens LG1 first lens group LG2 second lens group LG3 third lens group P1 first prism P1-a entrance surface P1-b exit surface P2 second prism P2-a entrance surface P2-b exit surface

Claims (4)

A lens frame that can move straight along one direction and has a lens support hole;
A relief recess recessed on the surface of the lens frame at a position located on the outer peripheral side of the lens frame, recessed toward the lens support hole and closed at least one end in the one direction;
A moving lens fixed in the lens support hole and having its own optical axis parallel to the one direction;
A screw rod that is rotatable about its own axis parallel to the optical axis of the moving lens;
A nut screwed with the screw rod and restricted in relative movement in the optical axis direction with respect to the lens frame;
An engaging portion that regulates rotation of the nut around the axis by contacting the lens frame outside the relief recess formed on the nut;
A loose fitting end portion that is formed on the nut and is located closer to the moving lens than the screw rod and loosely fits in the relief recess;
With
An end surface on the lens support hole side of the loose fitting end portion is constituted by a nut side plane orthogonal to a straight line connecting the optical axis and the axis,
A lens driving device, wherein a concave-side plane opposed to the nut-side plane and the linear direction is formed on a side surface of the lens support hole on an inner surface of the escape recess. The lens driving device according to claim 1,
When viewed in a direction perpendicular to the optical axis and the straight line in a state where the loose fitting end is loosely fitted in the relief recess on the outer surface of the nut, the screw rod side is more than the nut side plane. Forming a corner facing portion located at
A lens driving device in which a corner formed between the end surface in the optical axis direction of the inner surface of the escape recess and the recess-side flat surface is formed by a corner configuration surface facing the corner facing portion. The lens driving device according to claim 2, wherein
On the surface of the part located on the outer peripheral side of the lens support hole of the lens frame, a nut receiving recess for inserting the nut is provided,
The both end surfaces of the nut in the optical axis direction constitute a pair of lens frame contact surfaces that are orthogonal to the optical axis and contact the inner surface of the nut receiving recess,
The entire nut side plane is located closer to the other lens frame contact surface than the one lens frame contact surface, and the optical axis dimension of the nut side plane is between the pair of lens frame contact surfaces. Shorter than the optical axis direction interval of
The optical axis and the straight line in a state where the corner facing portion connects the one lens frame contact surface and the nut-side plane, and the loose fitting end is loosely fitted in the relief recess. A lens driving device that is a flat surface inclined toward the screw rod side with respect to the nut-side flat surface when viewed in a direction perpendicular to the nut side. In the lens drive device according to any one of claims 1 to 3,
On the surface of the part located on the outer peripheral side of the lens support hole of the lens frame, a recess for rotation prevention is formed by changing the position from the recess for escape.
A lens driving device in which the engaging portion of the nut is a rotation-preventing convex portion that fits into the rotation-preventing concave portion.

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