Optical unit with shake correction function and bending method of flexible printed circuit board

Abstract

An optical unit (1) with a shake correction function performs shake correction by swinging a movable body (5). A flexible printed substrate (9) has a fixed portion (93) fixed to a fixed body (8) and a bending portion (97A, 97B) arranged between the fixed portion (93) and the movable body (5). The bending portion (97A, 97B) is a shape extending in a direction inclined relative to the Z-axis direction and the X-axis direction and folded back in the Z-axis direction, and is a shape folded back in the Y-axis direction when viewed from the Z-axis direction. Therefore, since the spring constant of the flexible printed substrate (9) is small when the movable body (5) swings around three axes, the swing load is small. In addition, since the bending portion (97A, 97B) folds the flexible printed substrate (9) in one direction, the bending work can be reduced compared to the case of bending in multiple directions, and the shape accuracy is also high.

Description

Technical Field

[0001] The present invention relates to an optical unit with a shake correction function for correcting shake by swinging an optical module, and a method for bending a flexible printed circuit board connected to the optical module. Background Art

[0002] An optical unit mounted on a portable terminal or mobile object includes a mechanism for correcting image shake by swinging or rotating the movable body on which the optical module is mounted, in order to suppress image distortion when the portable terminal or mobile object is moving. Patent Document 1 discloses such an optical unit with a shake correction function.

[0003] The optical unit with a shake correction function disclosed in Patent Document 1 comprises a movable body equipped with an optical module, a fixed body, and a swing support mechanism that supports the movable body so that it can rotate relative to the fixed body about rotation axes (X and Y axes) that intersect the optical axis. This optical unit with a shake correction function swings the movable body in the pitch and yaw directions. A flexible printed circuit board (flexible wiring board) connected to the optical module is extended from the movable body.

[0004] In an optical unit with a shake correction function, the movable body oscillates while bending the flexible printed circuit board. The elasticity of the flexible printed circuit board hinders the movement of the movable body, increasing the load required to swing the movable body. In Patent Document 1, the flexible printed circuit board is folded back so that it overlaps when viewed along the optical axis to facilitate bending.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-86367 Summary of the Invention

[0008] Technical problem to be solved by the invention

[0009] To swing a movable body not only in pitch and yaw but also in roll, flexible printed circuit boards (FPCs) have traditionally been folded in multiple directions to create a shape with a low spring constant, making them easier to flex. However, the complex folding required reduces the ease of assembly of the FPCs. Furthermore, folding in multiple directions or multiple times makes it difficult to maintain shape accuracy.

[0010] In view of the above problems, the present invention aims to suppress a decrease in assemblability and a decrease in shape accuracy of a flexible printed circuit board connected to a movable body.

[0011] Technical solutions used to solve technical problems

[0012] In order to solve the above technical problems, the optical unit with a shake correction function of the present invention is characterized in that it comprises: a movable body, which has an optical module; a fixed body; a swing support mechanism, which supports the movable body relative to the fixed body so that it can swing around the X axis and supports the movable body so that it can swing around the Y axis when three axes orthogonal to each other are set as the X axis, the Y axis, and the Z axis and the direction along the optical axis of the optical module is set as the Z axis; a rolling support mechanism, which supports the movable body relative to the fixed body so that it can swing around the Z axis; a swing drive mechanism, which swings the movable body around the X axis and the Y axis; a rolling drive mechanism, which swings the movable body around the Z axis; and a flexible printed circuit board, which is led out from the movable body. The flexible printed circuit board includes: a lead-out portion, which is led out from the movable body in the X-axis direction; a fixed portion, which is fixed to the fixed body at a position away from the movable body in the X-axis direction; and one or more bent portions, which are arranged between the lead-out portion and the fixed portion, the bent portion including: a first inclined portion, which extends in a direction toward one side of the Z-axis direction along with the side toward the X-axis direction; and a second inclined portion, which is connected to the first inclined portion via a first folding portion and extends in a direction toward the other side of the Z-axis direction along with the side toward the X-axis direction, and when viewed from the Z-axis direction, the first inclined portion and the second inclined portion are in a shape that is folded back in the Y-axis direction via the first folding portion.

[0013] According to the present invention, a flexible printed circuit board extending from a movable body in a direction (X-axis direction) intersecting the optical axis (Z-axis direction) includes a bent portion disposed between a fixed portion fixed to the fixed body and the movable body. The bent portion extends in a direction oblique to the Z-axis and X-axis directions and then bends back in the Y-axis direction when viewed from the Z-axis direction. This bent shape facilitates the flexible printed circuit board's deflection when the movable body swings about three axes, thereby suppressing an increase in the swing load on the movable body. In particular, since the first and second inclined portions constituting the bent portion extend in directions oblique to each of the X-axis, Y-axis, and Z-axis directions, the bent shape can be reduced, and the lengths of the first and second inclined portions can be increased. Consequently, the spring constant can be reduced, thereby reducing the swing load on the movable body. Furthermore, since the flexible printed circuit board only needs to be folded in one direction, the bending effort can be reduced compared to bending in multiple directions, thus suppressing a decrease in assembly efficiency. Furthermore, a decrease in the shape accuracy of the flexible printed circuit board can be suppressed.

[0014] In the present invention, it is preferred to provide a plurality of the bent portions arranged in the X-axis direction, and the height of the bent portion closest to the movable body in the Z-axis direction is smaller than that of the other bent portions. In this way, by reducing the height in the Z-axis direction of the portion close to the movable body, the moving distance of the flexible printed substrate in the optical axis direction (Z-axis direction) when the movable body is tilted can be reduced. Therefore, the possibility of interference between the flexible printed substrate and the housing that accommodates the movable body is small, and the height in the optical axis direction (Z-axis direction) of the optical unit with a shake correction function can be reduced. In addition, by increasing the height in the Z-axis direction of the portion away from the movable body, the spring constant of the flexible printed substrate can be reduced, making it easier to bend. Therefore, the increase in the swing load of the movable body can be suppressed.

[0015] In the present invention, a second folded portion is preferably provided connecting adjacent bent portions in the X-axis direction, with the second folded portion being positioned differently from the first folded portion in the Y-axis direction. By staggering the folded portions, the flexible portion exhibits a serpentine shape not only in side view but also in plan view when viewed from the Z-axis. This facilitates deflection of the flexible printed circuit board even when oscillating in any of the three axes. Furthermore, by staggering the folded portions, the lengths of the first and second inclined portions are increased. This reduces the spring constant, thereby suppressing an increase in the oscillation load on the movable body 5.

[0016] In the present invention, it is preferable to include bending assisting members attached to the first and second folded portions. This facilitates maintaining the shape of the folded portions. Therefore, when the movable body is returned to its origin, the flexible printed circuit board easily returns to its original shape, thereby maintaining a readily bendable state.

[0017] In the present invention, the flexible printed circuit board preferably includes a first surface and a second surface facing the back of the first surface, and all of the bending assisting components are mounted on one of the first surface and the second surface. This facilitates mounting the bending assisting components on the flexible printed circuit board.

[0018] In the present invention, the flexible printed circuit board preferably includes a first surface and a second surface facing away from the first surface. At the first folded portion, the flexible printed circuit board is folded so that the first surface forms a mountain fold, and the bending assisting component is attached to the first surface. At the second folded portion, the flexible printed circuit board is folded so that the second surface forms a mountain fold, and the bending assisting component is attached to the second surface. In this manner, the bending assisting component can be used to maintain the folded portion from the outer periphery at both the first and second folded portions. Furthermore, when the bending assisting component is folded together with the flexible printed circuit board, it can be pressed from the bending assisting component side to deform it. Consequently, the likelihood of wiring within the flexible printed circuit board being disconnected is minimized.

[0019] In the present invention, the bending assist component preferably includes: a first fixing portion fixed to the first inclined portion; a second fixing portion fixed to the second inclined portion; and a curved portion connecting the first and second fixing portions, wherein the first and second fixing portions extend in the width direction of the flexible printed circuit board, and the curved portion connects a portion of the first and second fixing portions in the width direction. Alternatively, the curved portion may include: a first curved portion connecting one end of the first and second fixing portions in the width direction; and a second curved portion connecting the other end of the first and second fixing portions in the width direction. This reduces the area of stress applied to the flexible printed circuit board when the bending assist component is bent together with the flexible printed circuit board. Consequently, the possibility of wiring within the flexible printed circuit board being disconnected during bending of the curved portion can be reduced.

[0020] In the present invention, the fixed portion is preferably connected to one of the first inclined portion and the second inclined portion, and the fixed portion extends in the same direction as one of the first inclined portion and the second inclined portion. This allows the fixed portion to be connected to the first inclined portion or the second inclined portion in a straight line. Therefore, since the flexible printed circuit board does not need to be bent between the fixed portion and the flexible portion, the number of times the flexible printed circuit board needs to be bent can be reduced. Consequently, a decrease in the shape accuracy of the flexible printed circuit board can be suppressed.

[0021] In the present invention, it is preferred to provide two flexible printed substrates arranged in the Y-axis direction, and the two flexible printed substrates are symmetrically constructed with respect to an imaginary plane passing through the swing center of the movable body and parallel to the XZ plane. If the flexible printed substrate is divided into two, it can be made thinner, so the height and width of the bent portion can be reduced. Therefore, the outer shape of the flexure can be reduced, and the height of the optical axis direction (Z-axis direction) of the optical unit with a shake correction function can be reduced. In addition, compared with the case of using a thick flexible printed substrate, the spring constant is small and it is easy to bend, so the load when the movable body is swung can be reduced. Moreover, by forming a shape that is symmetrical with respect to an imaginary plane passing through the swing center of the movable body, it can be deformed with good balance when the movable body is swung.

[0022] Next, the present invention is a method for bending a flexible printed substrate included in the above-mentioned optical unit with a shake correction function, characterized in that the flexible printed substrate having a shape folded back in a plane is placed on a die having a receiving surface having a shape consistent with the bent shape of the bent portion, and the flexible printed substrate is pushed against the receiving surface using a punch having a pressing surface having a reverse shape of the receiving surface, thereby bending the flexible printed substrate into the shape of the bent portion.

[0023] The bending method of the present invention simply requires placing the flexible printed circuit board on a die and pressing the punch against the die. This makes bending easier and with higher shape accuracy than manual bending. This reduces the amount of time required for the bending operation and minimizes degradation in assembly efficiency. Furthermore, it minimizes degradation in the shape accuracy of the flexible printed circuit board.

[0024] Effects of the Invention

[0025] According to the present invention, a flexible printed circuit board extending from a movable body in a direction (X-axis direction) intersecting the optical axis (Z-axis direction) includes a bent portion disposed between a fixed portion fixed to the fixed body and the movable body. The bent portion extends in a direction oblique to the Z-axis and X-axis directions and then bends back in the Y-axis direction when viewed from the Z-axis direction. This bent shape facilitates the flexible printed circuit board's deflection when the movable body swings about three axes, thereby suppressing an increase in the swing load on the movable body. In particular, since the first and second inclined portions constituting the bent portion extend in directions oblique to each of the X-axis, Y-axis, and Z-axis directions, the bent shape can be reduced, and the lengths of the first and second inclined portions can be increased. Consequently, the spring constant can be reduced, thereby reducing the swing load on the movable body. Furthermore, since the flexible printed circuit board only needs to be folded in one direction, the bending effort can be reduced compared to bending in multiple directions, thus suppressing a decrease in assembly efficiency. Furthermore, a decrease in the shape accuracy of the flexible printed circuit board can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a top view of an optical unit with a shake correction function to which the present invention is applied.

[0027] Figure 2 This is a side view of an optical unit with a shake correction function to which the present invention is applied.

[0028] Figure 3 This is an exploded perspective view of the flexible printed circuit board and bending assist components.

[0029] Figure 4 This is an expanded view of a flexible printed circuit board.

[0030] Figure 5 This is a perspective view of a processing tool used in bending a flexible printed circuit board and a flexible printed circuit board.

[0031] Figure 6 This diagram explains how to bend a flexible printed circuit board.

[0032] Figure 7 It is a diagram showing the simulation results of the shape of the flexible printed circuit board when the shake correction in the pitch direction is performed.

[0033] Figure 8 It is a diagram showing the simulation results of the shape of the flexible printed circuit board when the shake correction in the yaw direction is performed.

[0034] Figure 9 It is a diagram showing the simulation results of the shape of the flexible printed circuit board when shake correction in the rolling direction is performed.

[0035] Figure 10 It is a side view showing another example of the mounting position of the bending assisting member.

[0036] Figure 11 It is an explanatory diagram of a bending assisting member according to a modified example. DETAILED DESCRIPTION

[0037] Hereinafter, an embodiment of an optical unit with a shake correction function to which the present invention is applied will be described with reference to the accompanying drawings.

[0038] (Overall structure)

[0039] Figure 1 1 is a top view of an optical unit 1 with a shake correction function to which the present invention is applied. Figure 2 1 is a side view of an optical unit 1 with a shake correction function to which the present invention is applied. Figure 1 、 Figure 2 In FIG. 1 , a part of the structure of the optical unit with a shake correction function 1 is schematically shown or omitted from the illustration.

[0040] An optical unit 1 with a shake correction function includes an optical module 4 equipped with a lens 2 and an imaging element 3. This unit is used in optical devices such as mobile phones with cameras, drive recorders, and action cameras or wearable cameras mounted on mobile devices such as helmets, bicycles, and radio-controlled helicopters. In such optical devices, if the optical device shakes during shooting, the captured image will be distorted. To prevent tilt in the captured image, the optical unit 1 with a shake correction function corrects the tilt of the optical module 4 based on acceleration, angular velocity, and the amount of shake detected by a detection unit such as a gyroscope.

[0041] In the following description, three mutually orthogonal axes are referred to as the X-axis, Y-axis, and Z-axis. The Z-axis coincides with the optical axis L of the optical module 4. The optical unit 1 with a shake correction function performs shake correction in the pitch and yaw directions by swinging the optical module 4 about the X-axis and Y-axis. Furthermore, the optical unit 1 with a shake correction function performs shake correction in the roll direction by rotating the optical module 4 about the Z-axis.

[0042] In the following description, directions along the X-axis, Y-axis, and Z-axis are referred to as the X-axis direction, Y-axis direction, and Z-axis direction. One side of the X-axis direction is referred to as the -X direction, and the other side is referred to as the +X direction. One side of the Y-axis direction is referred to as the -Y direction, and the other side is referred to as the +Y direction. One side of the Z-axis direction is referred to as the -Z direction, and the other side is referred to as the +Z direction. The Z-axis direction is the optical axis direction along the optical axis L. The -Z direction is the image side of the optical module 4, and the +Z direction is the subject side of the optical module 4.

[0043] like Figure 1 、 Figure 2 As shown, the optical unit 1 with a shake correction function includes: a movable body 5 including an optical module 4; a gimbal mechanism (not shown) and a rolling support mechanism (not shown); a fixed body 8 supporting the movable body 5 via the gimbal mechanism and the rolling mechanism; a swing drive mechanism 6; a rolling drive mechanism 7; and a flexible printed circuit board 9. The flexible printed circuit board 9 is connected to the movable body 5.

[0044] The movable body 5 includes an optical module 4 and a holder 5a surrounding the optical module 4. The optical module 4 includes a lens barrel 4a protruding from the center of the holder 5a in the +Z direction, and the lens barrel 4a holds the lens 2. A flexible printed circuit board 9 extends from the -Z end of the movable body 5 in the +Z direction.

[0045] The fixed body 8 includes a first housing 21 that houses the movable body 5 and the flexible printed circuit board 9, and a second housing 20 fixed to the -Z end of the first housing 21. Alternatively, the first housing 21 may be composed of multiple components. For example, the first housing 21 may include a housing that houses the movable body 5, a wiring housing that houses the flexible printed circuit board 9, and a cover that covers the housing and wiring housing. The flexible printed circuit board 9 is fixed to a substrate fixing portion 22 that protrudes from the +X end of the first housing 21 in the -Z direction.

[0046] The gimbal mechanism is a swing support mechanism that supports the movable body 5 so that it can swing around the first axis R1 and the second axis R2. The movable body 5 can swing around the intersection point of the optical axis L, the first axis R1 and the second axis R2, that is, the swing center P. By combining the rotation around the first axis R1 and the rotation around the second axis R2, the movable body 5 can rotate around the X axis and the Y axis. Therefore, the gimbal mechanism supports the movable body so that it can swing around the X axis, and supports the movable body so that it can swing around the Y axis. Figure 1 As shown, the first axis R1 and the second axis R2 are, for example, orthogonal to the optical axis L and inclined at 45 degrees with respect to the X axis and the Y axis.

[0047] The rolling support mechanism supports the movable body 5 so that it can swing about the optical axis L (about the Z axis). The gimbal mechanism and rolling support mechanism are well known, so detailed description and illustration are omitted. For example, the movable body 5 can be connected to the rolling support mechanism, and a gimbal mechanism can be formed between the rolling support mechanism and the fixed body 8.

[0048] The swing drive mechanism 6 includes a first swing drive mechanism 6X that generates a driving force about the X-axis for the movable body 5, and a second swing drive mechanism 6Y that generates a driving force about the Y-axis for the movable body 5. In this embodiment, the first swing drive mechanism 6X, the second swing drive mechanism 6Y, and the rolling drive mechanism 7 are all magnetic drive mechanisms in which a magnet 61 disposed on the movable body 5 and a coil 62 disposed on the fixed body 8 are radially opposed. Alternatively, the arrangement of the magnet 61 and coil 62 may be reversed.

[0049] like Figure 1 As shown, in this embodiment, the first swing drive mechanism 6X is arranged in the -Y direction of the movable body 5. The second swing drive mechanism 6Y is arranged in the -X direction of the movable body 5. Furthermore, the rolling drive mechanism 7 is arranged in the +Y direction of the movable body 5. The magnets 61 of the first and second swing drive mechanisms 6X and 6Y are polarized in the Z-axis direction. Meanwhile, the magnets 61 of the rolling drive mechanism 7 are polarized in the circumferential direction around the Z-axis.

[0050] (Flexible Printed Circuit Board)

[0051] like Figure 1 As shown, the flexible printed circuit board 9 includes two flexible printed circuit boards 9A and 9B extending in the X-axis direction. The flexible printed circuit boards 9A and 9B are symmetrically arranged about an imaginary plane V that passes through the swing center P of the movable body 5 and is parallel to the XZ plane. Each flexible printed circuit board 9A and 9B includes a lead portion 91 extending from the movable body 5 in the +X direction; a flexible portion 92 extending from the lead portion 91 in the +X direction; and a fixed portion 93 connected to the flexible portion 92. In this embodiment, the fixed portions 93 of the flexible printed circuit boards 9A and 9B are connected.

[0052] As described above, the fixed body 8 includes the substrate fixing portion 22 separated from the movable body 5 in the +X direction, and the fixed portion 93 is fixed to the fixing surface 23 provided at the front end of the substrate fixing portion 22 by an adhesive (see FIG. Figure 2 The fixing surface 23 is inclined toward the +Z direction as it moves toward the +X direction. The fixed portion 93 extends in the same direction as the +X direction end of the flexible portion 92 and is fixed to the fixing surface 23. In addition, the flexible printed circuit board 9 includes an extension portion 94 extending from the fixed portion 93 in the +X direction and a wiring substrate 95 provided at the front end of the extension portion 94. The extension portion 94 and the wiring substrate 95 are led out of the fixed body 8. The wiring substrate 95 is provided with terminals for connecting to an optical device equipped with the optical unit 1 with a shake correction function.

[0053] The flexible printed circuit board 9 comprises a base film made of a polyimide resin or the like, a conductor layer forming a wiring pattern, and a cover film. The flexible printed circuit board 9 can be a double-sided board with wiring patterns formed on both sides, or a single-sided board. Alternatively, it can be a multi-layered board with wiring patterns formed in multiple layers. A bending assisting member 10 is fixed to the flexure 92 to maintain the flexible printed circuit board 9 in its bent shape. A reinforcing plate 96 is fixed to the fixed portion 93.

[0054] like Figure 2 As shown, the flexure 92 includes multiple bent portions that are bent back into a shape that protrudes in the +Z direction. In this embodiment, the flexure 92 includes two bent portions 97A and 97B arranged in the X-axis direction. The two bent portions 97A and 97B have different heights in the Z-axis direction. In this embodiment, the Z-axis height H1 of the bent portion 97A closest to the movable body 5 is smaller than the Z-axis height H2 of the other bent portions 97B.

[0055] like Figure 2 As shown, the bending portions 97A and 97B respectively include a first inclined portion 971 and a second inclined portion 972 connected to the first inclined portion 971 via a first folding portion 973. The first inclined portion 971 extends in the direction toward the +Z direction (one side of the Z-axis direction) as it moves toward the +X direction (one side of the X-axis direction). In addition, the second inclined portion 972 extends in the direction toward the -Z direction (the other side of the Z-axis direction) as it moves toward the +X direction (one side of the X-axis direction). In this embodiment, the first inclined portion 971 and the second inclined portion 972 are inclined at 45° relative to the Z-axis direction. Therefore, the bending angle of the bending portions 97A and 97B is 90°. In this embodiment, the height of the flexure 92 in the Z-axis direction is reduced by tilting the first inclined portion 971 and the second inclined portion 972 relative to the Z-axis direction.

[0056] The bends 97A and 97B are connected via a second bend 974. The second bend 974 connects the second inclined portion 972 of the bend 97A and the first inclined portion 971 of the bend 97B. Figure 2 As shown, the flexure 92 is bent back at the first folding portion 973 to protrude in the +Z direction, and is bent back at the second folding portion 974 to protrude in the -Z direction. The flexure 92 is bent back in opposite directions at the first folding portion 973 and the second folding portion 974, extending in the X-axis direction while meandering.

[0057] The flexure 92 includes first folded portions 973 and second folded portions 974 at two locations, and folds back four times along the Z-axis. The second inclined portion 972 of the bent portion 97B is connected to the first inclined portion 971 at the +X-direction end of the flexure 92 via the second folded portion 974. The fixed portion 93 is connected to the first inclined portion 971 at the +X-direction end of the flexure 97 and is inclined in the same direction as the first inclined portion 971.

[0058] like Figure 1 As shown, the first folding portion 973 and the second folding portion 974 of the flexure 92 are positioned differently in the Y-axis direction. By staggering the positions of the first folding portion 973 and the second folding portion 974 in the Y-axis direction, each bending portion 97A, 97B has a shape that folds back in the Y-axis direction when viewed from the Z-axis direction. In this embodiment, the first inclined portion 971, the first folding portion 973, and the second inclined portion 972 are connected to form a shape that is curved in a semicircular shape when viewed from the Z-axis direction. In addition, the second inclined portion 972, the second folding portion 974, and the first inclined portion 971 are connected to form a shape that is curved in a semicircular shape when viewed from the Z-axis direction. In addition, in this embodiment, the first inclined portion 971 and the second inclined portion 972 are curved, but they can also be straight.

[0059] When viewed from the Z-axis direction, the flexible printed circuit boards 9A and 9B are folded back into symmetrical shapes with respect to the imaginary plane V. In the flexible printed circuit board 9A, the flexure 92 is folded back at the first folded portion 973 to project in the -Y direction, and at the second folded portion 974 to project in the +Y direction. Furthermore, in the flexible printed circuit board 9A, the first inclined portion 971 is inclined toward the -Y direction as it moves toward the +X direction. Furthermore, the second inclined portion 972 is inclined toward the +Y direction as it moves toward the +X direction.

[0060] On the other hand, in the flexible printed circuit board 9B, the flexure 92 is bent back at the first folded portion 973 to project in the +Y direction, and is bent back at the second folded portion 974 to project in the -Y direction. Furthermore, in the flexible printed circuit board 9B, the first inclined portion 971 is inclined toward the +Y direction as it moves toward the +X direction. Furthermore, the second inclined portion 972 is inclined toward the -Y direction as it moves toward the +X direction.

[0061] Figure 3 It is an exploded perspective view of the flexible printed circuit board 9 and the bending assisting member 10 . Figure 4 FIG is an expanded view of the flexible printed circuit board 9, showing a state before the bending process. Figure 2As shown, the bending assisting member 10 includes a first fixing portion 11 fixed to the first inclined portion 971 , a second fixing portion 12 fixed to the second inclined portion 972 , and a bending portion 13 connecting the first fixing portion 11 and the second fixing portion 12 .

[0062] like Figure 1 As shown in FIG. 1 , the bending auxiliary member 10 is a rectangular metal plate member extending in the width direction (Y direction) of the flexible printed circuit board 9. Figure 2 As shown, the flexible printed circuit board 9 includes a first surface 901 facing the +Z direction and a second surface 902 facing the back side (-Z direction) of the first surface 901. In this embodiment, the bending assisting member 10 is entirely fixed to the first surface 901. The first folded portion 973 bends the first surface 901 into a mountain fold shape, and the bending assisting member 10 is fixed to the outer peripheral surface of the first folded portion 973. Meanwhile, the first surface 901 is bent into a valley fold shape in the second folded portion 974, and the bending assisting member 10 is fixed to the inner peripheral surface of the second folded portion 974.

[0063] In this embodiment, the bending auxiliary member 10 is fixed to the flexible printed substrate 9 before the bending process, and the bending auxiliary member 10 is bent simultaneously when the flexible printed substrate 9 is bent. Figure 4 As shown, the bending assisting members 10 are fixed to the flexible printed circuit board 9 before the bending process using an adhesive or double-sided tape, with the bending portion 13 not bent. For example, the first fixing portion 11 and the second fixing portion 12 of each bending assisting member 10 are fixed to the flexible printed circuit board 9.

[0064] (Flexible Printed Circuit Board Bending Method)

[0065] Figure 5 1 is a perspective view of a processing tool for bending a flexible printed substrate 9 and a flexible printed substrate 9 before processing. Figure 5 As shown, the processing tool is composed of a die 110 and punches 120, 130, 140. The die 110 includes receiving surfaces 111, 112, 113, 114, 115 arranged to have the same shape as the curved shape of the flexure 92, and includes a recess 116 for arranging the movable body 5.

[0066] Punch 120 includes pressing surfaces 121 and 122 having the same shape as the curved shape of bent portion 97A. Punch 130 includes pressing surfaces 131 and 132 having the same shape as the curved shape of bent portion 97B. Punch 140 includes pressing surface 141 having the same inclination angle as first inclined portion 971 disposed at the +X end of flexure 92.

[0067] Figure 61 is an explanatory diagram of a bending method for a flexible printed substrate 9. The bending method of this embodiment is a method of bending a flexible printed substrate 9 by punching it with a die 110 and punches 120, 130, 140. In the first step, Figure 6 As shown in (a) of FIG. 1 , the movable body 5 is disposed in a recess 116 provided in the die 110 , and the flexible printed circuit board 9 is provided in a state extending on the receiving surfaces 111 to 115 .

[0068] Then, in the second step, Figure 6 As shown in (b), punch 120 is pressed against receiving surfaces 111 and 112 to form bent portion 97A. At this time, punch 120 is pressed while tension is applied to the flexible printed circuit board 9 by stretching the flexible printed circuit board 9 in a direction along receiving surface 112 using an elastic member or the like. In the second step, the flexible printed circuit board 9 is bent so that the surface (first surface 901) on the side where the bending assisting member 10 is attached forms a mountain fold, forming first folded portion 973. Furthermore, the first bending assisting member 10 is bent around the outer periphery of first folded portion 973 to form bent portion 13.

[0069] Then, in the third step, Figure 6 As shown in (c), the punch 130 is pressed against the receiving surfaces 113 and 114, forming the bent portion 97B in the same manner as in the second step. At this point, as in the second step, the flexible printed circuit board 9 is stretched along the receiving surface 114 using an elastic member or the like, pressing the punch 130 while applying tension to the flexible printed circuit board 9. In the third step, the first first folded portion 973 is bent in the +X direction so that the first surface 901 forms a valley fold, forming the first second folded portion 974. Furthermore, the second bending assisting member 10 is bent on the inner periphery of the second folded portion 974, forming the bent portion 13. Simultaneously, the flexible printed circuit board 9 is bent in the +X direction so that the first surface 901 forms a mountain fold, forming the second first folded portion 973. Furthermore, the third bending assisting member 10 is bent on the outer periphery of the second first folded portion 973, forming the bent portion 13.

[0070] Then, in the fourth step, Figure 6As shown in (d), the punch 140 is pressed against the receiving surface 115, and the flexible printed circuit board 9 and the bending assisting member 10 are bent in the same manner as in the second and third steps. This forms a first inclined portion 971 at the end of the flexure 92. In the fourth step, the first surface 901 is bent in the +X direction of the second first folded portion 973 so that it forms a valley fold, forming a second second folded portion 974. Furthermore, the fourth bending assisting member 10 is bent on the inner circumference of the second folded portion 974, forming the bent portion 13. Then, the punches 120, 130, and 140 are retracted from the die 110, and the flexible printed circuit board 9 and the movable body 5 are removed from the die 110.

[0071] (Main effects of this embodiment)

[0072] As described above, the optical unit with a shake correction function of the present embodiment includes: a movable body 5, which has an optical module 4; a fixed body 8; a swing support mechanism, which supports the movable body 5 relative to the fixed body 8 so that it can swing around the X axis and supports the movable body 5 so that it can swing around the Y axis when three axes orthogonal to each other are set as the X axis, the Y axis, and the Z axis and the direction along the optical axis of the optical module 4 is set as the Z axis; a rolling support mechanism, which supports the movable body 5 relative to the fixed body 8 so that it can swing around the Z axis; a swing drive mechanism 6, which swings the movable body 5 around the X axis and around the Y axis; a rolling drive mechanism 7, which swings the movable body 5 around the Z axis; and a flexible printed substrate 9, which is extended from the movable body 5. The flexible printed circuit board 9 includes a lead portion 91 extending from the movable body 5 in the X-axis direction; a fixed portion 93 fixed to the fixed body 8 at a position spaced apart from the movable body 5 in the X-axis direction; and one or more bent portions 97A and 97B disposed between the lead portion 91 and the fixed portion 93. Each bent portion 97A and 97B includes a first inclined portion 971 extending toward one side in the Z-axis direction as it extends toward one side in the X-axis direction; and a second inclined portion 972 connected to the first inclined portion 971 via a first folded portion 973 and extending toward the other side in the Z-axis direction as it extends toward one side in the X-axis direction. When viewed from the Z-axis direction, the first inclined portion 971 and the second inclined portion 972 are connected via the first folded portion 973 to form a shape folded back in the Y-axis direction.

[0073] According to this embodiment, the flexible printed circuit board 9, which extends from the movable body 5 in a direction (X-axis direction) intersecting the optical axis (Z-axis direction), is bent one or more times between the fixed portion 93 fixed to the fixed body 8 and the movable body 5. The bent portions 97A and 97B extend and bend in directions oblique to the Z-axis and X-axis directions, and also bend in the Y-axis direction when viewed from the Z-axis direction. This bent shape facilitates the flexible printed circuit board 9 to flex when the movable body 5 swings in any of the three axes, thereby reducing the swing load on the movable body 5. In particular, since the first and second inclined portions 971 and 972 extend in directions oblique to each of the X-axis, Y-axis, and Z-axis directions, the lengths of the first and second inclined portions 971 and 972 can be increased while reducing the Z-axis height of the flexible portion 92. This allows for a lower-profile optical unit 1 with a shake correction function, and reduces the spring constant of the flexure 92, thereby reducing the swing load on the movable body 5. Furthermore, since the flexible printed circuit board 9 only needs to be folded in one direction, the bending effort required can be reduced compared to folding in multiple directions, thereby minimizing degradation in assemblability. Furthermore, degradation in the shape accuracy of the flexible printed circuit board 9 can be minimized.

[0074] Figure 7 、 Figure 8 、 Figure 9 It is a diagram showing the simulation results of the deflection shape of the flexible printed circuit board 9 when shake correction is performed. Figure 7 This is a diagram showing the pitch direction shake correction. Figure 8 This is a diagram showing the situation when the jitter correction in the deflection direction is performed. Figure 9 This is a diagram for correcting shake in the rolling direction. Figure 7 、 Figure 8 、 Figure 9 As shown, the flexible printed circuit board 9 will not be greatly deformed to the extent of contacting the fixed body 8 regardless of the direction in which it is swung.

[0075] In this embodiment, the flexible printed circuit board 9's flexure 92 includes multiple bends 97A and 97B arranged in the X-axis direction. The bends 97A and 97B closest to the movable body 5 have a smaller Z-axis height than the other bends 97A and 97B. By reducing the Z-axis height of the portion closest to the movable body 5, the distance the flexible printed circuit board 9 moves in the optical axis (Z-axis) direction when the movable body 5 tilts can be reduced. Consequently, the flexible printed circuit board 9 is less likely to interfere with the housing housing the movable body 5. Furthermore, by increasing the Z-axis height of the portion farther from the movable body 5, the spring constant of the flexible printed circuit board 9 can be reduced, making it easier to bend. Consequently, an increase in the swing load on the movable body 5 can be suppressed.

[0076] In this embodiment, a second folded portion 974 is provided, connecting the adjacent bent portions 97A and 97B in the X-axis direction. The second folded portion 974 and the first folded portion 973 are positioned differently in the Y-axis direction. By staggering the upper and lower folded portions, the planar shape viewed from the Z-axis becomes serpentine, making it easier for the flexible printed circuit board 9 to flex even when swung in any of the three axes. Furthermore, by staggering the folded portions, the lengths of the first inclined portion 971 and the second inclined portion 972 are increased. This reduces the spring constant, thereby suppressing an increase in the swing load on the movable body 5.

[0077] In this embodiment, the bending assisting member 10 attached to the first folded portion 973 and the second folded portion 974 facilitates maintaining the bending angle of each folded portion. Therefore, when the movable body 5 is returned to its origin, the flexible printed circuit board 9 easily returns to its original shape, allowing the flexible printed circuit board 9 to be maintained in a readily bendable state.

[0078] In this embodiment, the flexible printed circuit board 9 includes a first surface 901 and a second surface 902 facing the back side of the first surface 901, but all the bending assisting components 10 are mounted on the first surface 901. Therefore, there is no need to confirm each time on which surface each bending assisting component 10 is mounted, making it easy to mount the bending assisting components 10 on the flexible printed circuit board 9.

[0079] In this embodiment, the fixed portion 93 is connected to the first inclined portion 971 provided at the +X-direction end of the flexible portion 92, and the fixed portion 93 extends in the same direction as the first inclined portion 971. As a result, the first inclined portion 971 provided at the +X-direction end of the flexible portion 92 and the fixed portion 93 are aligned, eliminating the need to bend the flexible printed circuit board 9 between the fixed portion 93 and the flexible portion 92. This reduces the number of bends required for the flexible printed circuit board 9, improving assembly efficiency and preventing degradation in the shape accuracy of the flexible printed circuit board 9.

[0080] In this embodiment, two flexible printed circuit boards 9A and 9B are arranged in the Y-axis direction. These two flexible printed circuit boards 9A and 9B are symmetrically arranged with respect to an imaginary plane V passing through the swing center of the movable body 5 and parallel to the XZ plane. Splitting the flexible printed circuit board 9 into two pieces allows it to be thinner, thereby reducing the height and width of the bent portions 97A and 97B. This reduces the outer shape of the flexure 92 and the height of the optical unit 1 with a shake correction function in the optical axis direction (Z-axis direction). Furthermore, compared to using a single thick flexible printed circuit board, the spring constant is smaller, making it easier to bend, thereby reducing the load on the movable body during swing. Furthermore, by forming the flexible printed circuit board symmetrically with respect to the imaginary plane V passing through the swing center of the movable body 5, the movable body 5 can deform in a well-balanced manner during swing.

[0081] In this embodiment, the flexible printed circuit board 9's flexure 92 is bent using the following bending method. Specifically, the flexible printed circuit board 9 is bent into the shape of the bent portion by performing a first step and second to fourth steps. The first step places the flexible printed circuit board 9, which has been folded back in the Y-axis direction within the XY plane, on a die 110 having receiving surfaces 111 to 115 that correspond to the bent shape of the bent portions 97A and 97B. The second to fourth steps press the flexible printed circuit board 9 against the receiving surfaces 111 to 115 using punches 120, 130, and 140 having pressing surfaces 121, 122, 131, 132, and 141 that are inverses of the receiving surfaces 111 to 115. This method requires only placing the flexible printed circuit board 9 on the die 110 and pressing the punches 120, 130, and 140. Therefore, compared to manual bending, the flexible printed circuit board 9 can be bent more easily and with higher shape accuracy. Therefore, the time and effort required for the bending work can be reduced, and a decrease in assemblability can be suppressed. In addition, a decrease in the shape accuracy of the flexible printed circuit board 9 can be suppressed.

[0082] (Variation)

[0083] (1) In the above embodiment, the flexure 92 is provided with two bent portions 97A and 97B and a shape of half the bent portion (first inclined portion 971), but it is sufficient to have at least one bent portion, and it may be three or more. In addition, it is also possible not to include the shape of half the bent portion (first inclined portion 971). In the case where the shape of half the bent portion is not included, the fixed portion 93 is connected to the second inclined portion 972. Therefore, in this case, it is sufficient to adopt a structure in which the fixed portion 93 is inclined in the same direction as the second inclined portion 972 and extends in the same direction as the second inclined portion 972.

[0084] (2) In the above embodiment, the bending assisting member 10 is a metal plate member that bends together with the flexible printed circuit board 9 when it is bent. However, a member having a pre-curved shape may be prefabricated and attached to the first folded portion 973 and the second folded portion 974 after the flexible printed circuit board 9 is bent. In this case, the bending assisting member 10 may be made of a material other than metal. For example, it may be made of resin.

[0085] (3) In the above embodiment, the bending assisting member 10 is plate-shaped and fixed to the flexible printed circuit board 9 with an adhesive or double-sided tape. However, the bending assisting member 10 may also be shaped so as to include a clamping portion for clamping the flexible printed circuit board 9. For example, a structure in which the ends of a metal plate member are bent to clamp the flexible printed circuit board 9 may be employed.

[0086] (4) In the above embodiment, all the bending assisting members 10 are mounted on the first surface 901 of the flexible printed circuit board 9. However, the bending assisting members 10 may be mounted on the surface of the mountain-folded side of each folded portion. Figure 10 1 is a side view showing another example of the mounting position of the bending auxiliary component 10. In the second folding portion 974, the flexible printed circuit board 9 is folded so that the second surface 902 becomes a mountain fold shape. Figure 10 In the example shown, the bending assisting member 10 is mounted on the second surface 902 of the second folded portion 974 .

[0087] exist Figure 10 In the illustrated example, the bending assisting member 10 is attached to the mountain-folded surface of both the first folded portion 973 and the second folded portion 974. Therefore, the bending assisting member 10 can be used to maintain the folded portion from the outer periphery of both the first folded portion 973 and the second folded portion 974. Furthermore, with this configuration, when the flexible printed circuit board 9 and the bending assisting member 10 are bent using the die 110 and punches 120-140, as in the aforementioned embodiment, the flexible printed circuit board 9 and the bending assisting member 10 can be deformed by pressing against the bending assisting member 10, not from the flexible printed circuit board 9. This reduces the possibility of wiring breakage within the flexible printed circuit board 9.

[0088] (5) In the above embodiment, the bending assisting member 10 is a rectangular plate-shaped member, but may be in another shape. Figure 11 (a) Figure 11 (b) is an explanatory diagram of a bending assist component of a modified example. Figure 11The bending auxiliary component 10A shown in (a) includes: a first fixing portion 11 fixed to the first inclined portion 971; a second fixing portion 12 fixed to the second inclined portion 972; and a bending portion 13A connecting the first fixing portion 11 and the second fixing portion 12. The first fixing portion 11 and the second fixing portion 12 extend substantially parallel to the width direction of the flexible printed circuit board 9, as in the above-mentioned embodiment. The bending portion 13A connects a portion of the first fixing portion 11 and the second fixing portion 12 in the width direction. Figure 11 In the example shown in (a), the bent portion 13A connects the ends of the first fixing portion 11 and the second fixing portion 12 on one side in the Y direction.

[0089] Figure 11 The bending assisting component 10B shown in (b) includes a first fixing portion 11 fixed to the first inclined portion 971; a second fixing portion 12 fixed to the second inclined portion 972; and a curved portion 13B connecting the first fixing portion 11 and the second fixing portion 12. As in the above-described embodiment, the first fixing portion 11 and the second fixing portion 12 extend substantially parallel to the width direction of the flexible printed circuit board 9. The curved portion 13B includes a first curved portion 14 connecting one end portion in the Y direction (one end in the width direction) of the first fixing portion 11 and the second fixing portion 12; and a second curved portion 15 connecting the other end portion in the Y direction (the other end in the width direction) of the first fixing portion 11 and the second fixing portion 12.

[0090] By using Figure 11 (a) Figure 11 The bending assist components 10A and 10B shown in (b) can achieve lightweighting of the bending assist component 10A. Furthermore, the curved portions 13A and 13B have a smaller width in the Y direction than the curved portion 13 in the above-described embodiment, making them easier to bend. Furthermore, even if the Y-direction width of the curved portions 13A and 13B is smaller, the receiving surfaces 111, 112, 113, 114, and 115 provided on the die 110 and the pressing surfaces 121, 122, 131, 132, and 141 provided on the punches 120, 130, and 140 can be made the same width as the curved portions 13A and 13B. This allows for miniaturization of the die 110 and the punches 120, 130, and 140. Furthermore, the flexible printed circuit board 9 applies pressing force only within the range overlapping the curved portions 13A and 13B. This reduces the likelihood of wiring breakage within the flexible printed circuit board 9.

[0091] Explanation of symbols

[0092] 1…Optical unit with shake correction function; 2…Lens; 3…Image sensor; 4…Optical module; 4a…Lens barrel; 5…Movable body; 5a…Holding frame; 6…Oscillating drive mechanism; 6X…First oscillating drive mechanism; 6Y…Second oscillating drive mechanism; 7…Rolling drive mechanism; 8…Fixed body; 9…Flexible printed circuit board; 9A, 9B…Flexible printed circuit board; 10, 10A, 10B…Bending auxiliary member; 11…First fixing portion; 12…Second fixing portion; 13, 13A, 13B…Bending portion; 14…First bending portion; 15…Second bending portion; 20…First housing; 21…Second housing; 22…Substrate fixing portion; 23…Fixed surface; 61…Magnet; 62…Wire Loop; 91…lead-out portion; 92…flexure portion; 93…fixed portion; 94…extension portion; 95…wiring substrate; 96…reinforcement plate; 97A, 97B…bending portion; 110…die; 111, 112, 113, 114, 115…bearing surface; 116…recess; 120…punch; 121, 122…pressing surface; 130…punch; 131, 132…pressing surface; 140…punch; 141…pressing surface; 901…first surface; 902…second surface; 971…first inclined portion; 972…second inclined portion; 973…first folding portion; 974…second folding portion; L…optical axis; P…swing center; R1…first axis; R2…second axis; V…imaginary surface.

Claims

1. An optical unit with a shake correction function, characterized in that: have: a movable body including an optical module; fixed body; a swing support mechanism that supports the movable body relative to the fixed body so that it can swing about the X-axis and supports the movable body so that it can swing about the Y-axis, when three mutually orthogonal axes are defined as an X-axis, a Y-axis, and a Z-axis and a direction along the optical axis of the optical module is defined as the Z-axis; a rolling support mechanism that supports the movable body relative to the fixed body so as to be able to swing about the Z axis; a swing drive mechanism for swinging the movable body about the X-axis and the Y-axis; a rolling drive mechanism that causes the movable body to swing about the Z axis; and a flexible printed substrate extending from the movable body; The flexible printed circuit board comprises: a lead portion extending from the movable body in the X-axis direction; a fixed portion fixed to the fixed body at a position away from the movable body in the X-axis direction; and one or more bent portions arranged between the lead portion and the fixed portion. The bending portion comprises: a first inclined portion extending in a direction toward one side in the Z-axis direction as it moves toward one side in the X-axis direction; as well as a second inclined portion connected to the first inclined portion via a first folded portion and extending in a direction toward one side in the X-axis direction and toward the other side in the Z-axis direction; When viewed from the Z-axis direction, the first inclined portion and the second inclined portion have a shape that is folded back in the Y-axis direction via the first folded portion.

2. The optical unit with a shake correction function according to claim 1, wherein: It has a plurality of the bent portions arranged along the X-axis direction, The height of the bent portion closest to the movable body in the Z-axis direction is smaller than that of the other bent portions.

3. The optical unit with a shake correction function according to claim 1 or 2, characterized in that: comprising a second folded portion connecting the adjacent folded portions in the X-axis direction, The second folded portion and the first folded portion are located at different positions in the Y-axis direction.

4. The optical unit with a shake correction function according to claim 3, wherein: A bending assisting member is provided which is attached to the first folded portion and the second folded portion.

5. The optical unit with a shake correction function according to claim 4, wherein: The flexible printed circuit board includes a first surface and a second surface facing the back side of the first surface. All of the bending assisting members are mounted on one of the first surface and the second surface.

6. The optical unit with a shake correction function according to claim 4, wherein: The flexible printed circuit board includes a first surface and a second surface facing the back side of the first surface. At the first folded portion, the flexible printed circuit board is bent so that the first surface has a mountain fold shape, and the bending auxiliary member is attached to the first surface. At the second folded portion, the flexible printed circuit board is folded so that the second surface has a mountain fold shape, and the bending assisting member is attached to the second surface.

7. The optical unit with a shake correction function according to any one of claims 4 to 6, characterized in that: The bending assisting member includes: a first fixing portion fixed to the first inclined portion; a second fixing portion fixed to the second inclined portion; and a bending portion connecting the first fixing portion and the second fixing portion. The first fixing portion and the second fixing portion extend in a width direction of the flexible printed circuit board, and the bent portion connects a portion of the first fixing portion and the second fixing portion in the width direction.

8. The optical unit with a shake correction function according to claim 7, wherein: The bent portion comprises: a first bent portion connecting one end of the first fixing portion and the second fixing portion in the width direction; and A second bent portion connects the other ends in the width direction of the first fixing portion and the second fixing portion.

9. The optical unit with a shake correction function according to any one of claims 1 to 8, characterized in that: The fixed portion is connected to one of the first inclined portion and the second inclined portion. The fixed portion extends in the same direction as one of the first inclined portion and the second inclined portion.

10. The optical unit with a shake correction function according to any one of claims 1 to 9, characterized in that: comprising two flexible printed circuit boards arranged in the Y-axis direction, The two flexible printed circuit boards are configured symmetrically with respect to an imaginary plane that passes through the swing center of the movable body and is parallel to the XZ plane.

11. A method for bending a flexible printed substrate, wherein the flexible printed substrate is a flexible printed substrate provided in the optical unit with a shake correction function according to any one of claims 1 to 10, characterized in that: The flexible printed circuit board having a shape folded back in a plane is set in a die having a receiving surface having a shape consistent with the bent shape of the bent portion. The flexible printed circuit board is pressed against the receiving surface by a punch having a pressing surface that is an inverse shape of the receiving surface, thereby bending the flexible printed circuit board into the shape of the bent portion.

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