JP7627715B2 - Lens drive device, camera device and electronic device - Google Patents

Description

The present invention relates to a lens driving device, a camera device, and an electronic device.

Electronic devices such as mobile phones and smartphones are equipped with small cameras. This type of small camera has a lens driving device, and as shown in Patent Document 1, for example, a lens driving device with an autofocus function is known. The autofocus function is achieved by moving a moving body having a lens support that supports the lens relative to a fixed base. The lens driving device is provided with a driving mechanism for driving the moving body relative to the base.

China Utility Model No. 210742590

In the above conventional example, the drive mechanism has support columns molded from resin integrally with the base at the four corners of the base so that they rise in the direction of the optical axis, and a substrate is attached to the support columns. Components that make up the drive mechanism, such as a coil, are fixed to the substrate. A magnet is provided on the fixed body side facing the coil.

However, because the components that make up this drive mechanism are supported via a resin support that stands upright as one with the base, shrinkage during molding of the base can cause the support to deform or collapse, causing the relative positions of the drive mechanism components to change from the original design, making it impossible to obtain stable drive characteristics.

The present invention aims to provide a lens drive device, camera device, and electronic device that can solve the above problems and obtain stable drive characteristics.

One aspect of the present invention is a lens driving device, which has a fixed body with a base, a movable body with a lens support that supports a lens, and a driving mechanism that drives the movable body relative to the fixed body, and the base has a base main body and a metal support plate provided on the base main body, and the support plate is formed with a support part that rises in the optical axis direction of the lens, and at least one part that constitutes the driving mechanism is supported via the support part.

Preferably, at least one component constituting the drive mechanism is fixed to a flexible printed circuit board, and the flexible printed circuit board is fixed to the support section. Also, preferably, at least one component constituting the drive mechanism is a coil or a position detection element. Also, preferably, the base is formed in a quadrangle shape when viewed from the optical axis direction of the lens, the support sections are provided at the four corners of the base, and the flexible printed circuit board is bent at the support sections. Also, preferably, at least one component constituting the drive mechanism is a coil, a magnet, or a position detection element. Also, preferably, the support section is formed by bending the support plate. Also, preferably, the lens support has a guide shaft that guides the movement of the lens support in the optical axis direction, and the guide shaft is fixed to the support plate. Even more preferably, the support plate is embedded in the base body.

Another aspect of the present invention is a camera device, which has the lens drive device and a lens supported by the lens support.

Yet another aspect of the present invention is an electronic device that includes the camera device.

According to the present invention, at least one component of the drive mechanism is supported via a metal support portion provided on the base, thereby improving the positional accuracy of the components that make up the drive mechanism, and providing a lens drive device, camera device, and electronic device that can obtain stable drive characteristics.

1 is a perspective view of a lens driving device according to an embodiment of the present invention, as viewed obliquely from the front. 1 is a perspective view of a lens device according to an embodiment of the present invention, as viewed obliquely from behind; 1 is an exploded perspective view of a lens driving device according to an embodiment of the present invention, with a fixed body and a movable body disassembled, as viewed obliquely from the front. 1 is an exploded perspective view of a lens driving device according to an embodiment of the present invention, with all components disassembled, as viewed obliquely from the front. 1 is an exploded perspective view of a lens driving device according to an embodiment of the present invention, with all components disassembled, as viewed obliquely from the rear. 1 is an exploded perspective view of a fixed body used in a lens driving device according to an embodiment of the present invention, disassembled into a base and a flexible printed circuit board, as viewed obliquely from the front. FIG. 1 is an exploded perspective view of a fixed body used in a lens driving device according to an embodiment of the present invention, as viewed obliquely from the front. 1 is an exploded perspective view of a base used in a lens driving device according to an embodiment of the present invention, disassembled into a base body and a support plate, and viewed obliquely from the front. FIG. 1 is a plan view showing a part of a lens driving device according to an embodiment of the present invention. 10 is a cross-sectional view taken along line AA of FIG. 9. 10 is a cross-sectional view taken along line BB of FIG. 9. FIG. 4 is an enlarged perspective view showing a guide wall used in the lens driving device according to the embodiment of the present invention.

An embodiment of the present invention will be described with reference to the drawings.

Figures 1 to 5 show a lens driving device 10 according to an embodiment of the present invention. The lens driving device 10 is used together with a lens in a camera device mounted on an electronic device such as a smartphone.

The lens driving device 10 has a fixed body 12 and a movable body 14 supported so as to be freely movable relative to the fixed body 12. As shown in Figures 4 and 5, the movable body 14 has a lens support 16 that supports a lens (not shown), and a first frame 18 that surrounds the lens support 16. The lens support 16 and the first frame 18 have a substantially rectangular external shape when viewed from the front.
In this specification, for convenience, the optical axis direction of the lens is referred to as the Z direction, the direction perpendicular to the optical axis direction is referred to as the X direction, and the direction perpendicular to the Z direction and the X direction is referred to as the Y direction. In addition, the subject side of the optical axis is referred to as the front side, and the opposite side where an image sensor (not shown) is disposed is referred to as the rear side.

A circular lens mounting hole 20 is formed on the inside of the lens support 16 when viewed from the Z direction, and the lens is mounted in this lens mounting hole 20.

The first frame 18 is composed of a first moving body plate 22, a second moving body plate 24, and a first cover 26. The lens support 16, the first moving body plate 22, and the second moving body plate 24 are made of engineering plastics such as liquid crystal polymer (LCP), polyacetal, polyamide, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, etc. The first cover 26 is made of metal, for example. The first moving body plate 22, the second moving body plate 24, and the first cover 26 are each formed with through holes 28, 30, and 32 for passing light. The through holes 28, 30, and 32 are each formed in an approximately circular shape.

The first frame 18 supports the lens support 16 so that it can move freely in the Y and X directions. That is, the first frame 18 has an orthogonal support mechanism 34, and the lens support 16 can be moved freely in the X and Y directions via this orthogonal support mechanism 34.

The orthogonal support mechanism 34 is composed of a first support mechanism 36 and a second support mechanism 38 separated in the Z direction. The first support mechanism 36 is provided rearward in the Z direction and is composed of a first support portion 40 formed as a protrusion protruding in the -Z direction on the rear surface of the first moving body plate 22, and a first guide portion 42 formed as a groove recessed in the -Z direction on the front surface of the second moving body plate 24. The first support portion 40 fits into the first guide portion 42. The first support portion 40 and the first guide portion 42 extend in the X direction and are formed near the four corners of the first moving body plate 22 and the second moving body plate 24. The first support portion 40 and the first guide portion 42 extending in the X direction are fitted together so as to restrict movement in the Y direction, so that the first moving body plate 22 is free to move only in the X direction relative to the second moving body plate 24.

The second support mechanism 38 is provided forward in the Z direction and is composed of a second support part 44 formed as a protrusion protruding in the +Z direction on the front surface of the first movable body plate 22, and a second guide part 46 formed as a groove recessed in the +Z direction on the rear surface of the lens support 16. The second support part 44 fits into the second guide part 46. The second support part 44 and the second guide part 46 extend in the Y direction and are formed near the four corners of the lens support 16 and the first movable body plate 22. The second support part 44 and the second guide part 46 extending in the Y direction fit together to restrict movement in the X direction, so that the lens support 16 is free to move only in the Y direction relative to the first movable body plate 22.

Attachment parts 48 are provided at the four corners of the first cover 26 so as to extend rearward in the Z direction. These attachment parts 48 have rectangular attachment holes 50 formed therein. Additionally, attachment receiving parts 52 are formed at the four corners of the second movable body plate 24 so as to protrude laterally. The attachment receiving parts 52 fit into the attachment holes 50, and the first cover 26 is fixed to the second movable body plate 24.

A first magnet 54 and a first yoke 56 are fixed to the +X side and -Y side surfaces of the outer surface of the lens support 16. The first magnet 54 on the +X side surface has an S pole and an N pole formed in the X direction. The first magnet 54 on the -Y side surface has an S pole and an N pole formed in the Y direction.

A second magnet 58 and a second yoke 60 are fixed to the +Y side surface of the second movable body plate 24. This second magnet 58 is divided into two in the Z direction, with an S pole and an N pole formed in the Y direction, and the polarity is reversed at the front and rear. A magnetic member 86 is fixed to the bottom surface of the second movable body plate 24 in correspondence with the rear of the first magnet 54. This causes the lens support 16 to be attracted to the second movable body plate 24 together with the first movable body plate 22, and the movable body 14 is assembled into a single member.

Next, the relationship between the fixed body 12 and the moving body 14 will be described. The fixed body 12 has a second frame 62. This second frame 62 surrounds the periphery of the first frame 18 of the moving body 14. This second frame 62 has a base 64 and a second cover 66 attached to this base 64. The base 64 and the second cover 66 are rectangular when viewed from the front, and the second frame 62 is formed by fitting the second cover 66 to the outside of the base 64. In addition, through holes 72, 74 are formed in the bottom surface portion 68 of the base 64 and the front surface portion 70 of the second cover 66 to pass light or to insert a lens.

At the four corners of the base 64, a support section 76 is formed that splits into two parts with the corners in between, rising forward from the bottom surface section 68. A flexible printed circuit board 78 is disposed on the outside of the base 64 so as to surround this support section 76. The flexible printed circuit board 78 is bent into a quadrangle so as to surround three sides of the exterior shape of the base 64 and fixed to the support section 76, and a terminal section 80 is formed at the rear of the flexible printed circuit board 78. The supply of electricity to a first coil 82 and a second coil 84, which will be described later, is controlled via this terminal section 80, but is not limited to this.

A first coil 82 is fixed to the +X direction portion and the -Y direction portion on the inside of the flexible printed circuit board 78. A second coil 84 is fixed to the +Y direction portion on the inside of the flexible printed circuit board 78. The first coil 82 faces the first magnet 54. The second coil 84 faces the second magnet 58. A position detection element 124 that detects the position of the moving body 14 is provided within the first coil 82.
In this embodiment, the coil and position detection element are provided on the fixed body 12 side and the magnet is provided on the movable body 14 side, but it is also possible to provide the magnet on the fixed body 12 side and the coil and position detection element on the movable body 14 side.

A magnetic member 86 made of a magnetic material is provided on the outside of the +Y direction portion of the flexible printed circuit board 78. This magnetic member 86 faces the second magnet 58 with the flexible printed circuit board 78 and the second coil 84 sandwiched between them. Since magnetic flux from the second magnet 58 flows through the magnetic member 86, an attractive force is generated between the second magnet 58 and the magnetic member 86. As a result, an attractive force acts on the moving body 14 in the +Y direction toward the fixed body 12.

The movable body 14 is supported by an optical axis direction support mechanism 88 so that it can move freely in the Z direction relative to the fixed body 12. The optical axis direction support mechanism 88 is composed of a main guide shaft 90 and a sub-guide shaft 92 provided on the base 64, and a guide hole 114 and a guide wall 116 provided on the movable body 14.

The main guide shaft 90 and the sub guide shaft 92 are made of metal, and in this embodiment, are configured as cylinders extending in the Z direction.
Although the main guide shaft 90 and the sub guide shaft 92 are circular in cross section in the XY direction, they may be part of a circle, or may be elliptical or polygonal in shape other than a circle.

The main guide shaft 90 and the sub guide shaft 92 are fixed at the rear end of the main guide shaft 90 near the -X+Y direction end of the bottom surface 68 of the base 64, and at the rear end of the sub guide shaft 92 near both ends of the bottom surface 68 of the base 64 in the +X+Y directions. They rise up toward the front in parallel with the Z direction.

As shown in Figures 6 to 8, the base 64 is composed of a base body 98 made of resin, and a metal support plate 100 that is located on the bottom surface 68 of the base 64 and embedded in the base body 98. The base 64 is insert molded so that the entire periphery of the support plate 100 is embedded in the base body 98. The support plate 100 is integrally formed with the aforementioned support column 76 by bending a part of the support plate 100 forward, and this support column 76 protrudes forward from the base body 98.

The flexible printed circuit board 78 is bent to fit the three sides of the base 64. The flexible printed circuit board 78 is connected to the support column 76 at the four corners of the base 64. Positioning holes 126 are formed near the corners of the flexible printed circuit board 78, and a positioning protrusion 128 protruding outward is formed on the support column 76. The positioning protrusion 128 fits into the positioning hole 126 to position the flexible printed circuit board 78. Cutouts 130 cut in the -Z direction are formed behind the three corners of the flexible printed circuit board 78. Steps 132 protruding in the +Z direction are formed at the four corners of the base body 98. The step portions 132 fit into the cutouts 130. The flexible printed circuit board 78 is fixed to the support column 76 via adhesive or the like after being positioned relative to the base 64.

As shown in Figures 9 to 12, the main guide shaft 90 and the sub-guide shaft 92 each have a guide shaft body 102, a flange 104, and an insertion portion 106 that are integrally formed from the front to the rear. The insertion portion 106 is formed at the rear end of the main guide shaft 90 and the sub-guide shaft 92, and the flange 104 is formed just before the insertion portion 106. This insertion portion 106 is formed thicker than the guide shaft body 102 so that the posture is more stable when assembled, and the flange 104 is further formed thicker than the guide shaft body 102 and the insertion portion 106.

On the other hand, the base 64 has a first insertion hole 108 formed in the support plate 100, and a second insertion hole 110 formed in the base body 98 so as to surround the periphery of the first insertion hole 108.

The insertion portions 106 of the main guide shaft 90 and the sub guide shaft 92 are inserted into the first insertion hole 108 of the support plate 100 and protrude into the second insertion hole 110 of the base body 98. In addition, the flange portions 104 of the main guide shaft 90 and the sub guide shaft 92 are inserted into the second insertion hole 110 of the base body 98 and abut against the support plate 100 around the first insertion hole 108 of the support plate 100.

The rear ends of the insertion portions 106 of the main guide shaft 90 and the sub guide shaft 92 are crimped to the support plate 100 to form crimped portions 112, and the periphery of the first insertion hole 108 of the support plate 100 is sandwiched between this crimped portion 112 and the flange portion 104, and the main guide shaft 90 and the sub guide shaft 92 are fixed to the support plate 100. The crimped portion 112 may be formed by normal press processing, but may also be formed by a method called high spin or spin crimping to reduce the effect of pressure on other parts. High spin or spin crimping is a processing method in which the tip to be processed is crushed with a rotating tool.

The main guide shaft 90 is inserted into a guide hole 114 formed in the second movable body plate 24. This guide hole 114 is divided into a front side portion and a rear side portion, and the main guide shaft 90 contacts the front side portion and the rear side portion of the guide hole 114. In addition, this guide hole 114 is formed in a V shape that widens in the +Y direction when viewed from the Z direction. As described above, the movable body 14 is attracted in the +Y direction by the magnetic member 86 and the second magnet 58, so that the main guide shaft 90 contacts the V-shaped end face of the guide hole 114 to secure the sliding position.

The sub-guide shaft 92 is sandwiched between two guide walls 116 formed on the second movable body plate 24. The two guide walls 116 are each composed of a surface parallel to the X direction. The guide walls 116 protrude from each other in a flat or curved shape so that the center of the guide wall 116 in the Z direction contacts the sub-guide shaft 92 from the +Y side and the -Y side. Therefore, the sub-guide shaft 92 guides the movable body 14 while contacting the protruding parts of the guide walls 116.

The sub-guide shaft 92 is shorter in the Z direction than the main guide shaft 90. As shown in FIG. 12, the two guide walls 116 are connected at the front via a front connection part 118. In this embodiment, the front connection part 118 is formed so as to close the entire front open part of the guide wall 116. In addition, at the rear of the guide wall 116, the periphery of the guide wall 116 except for the part where the sub-guide shaft 92 is inserted is connected by a rear connection part 120, and the guide wall 116 is box-shaped by the front connection part 118 and the rear connection part 120. Since the guide wall 116 is formed in a box shape in this way, the strength of the guide wall 116 is improved.

As shown in Figures 10 and 11, the height at which the guide wall 116 abuts against the sub-guide shaft 92 is between the heights of the two guide holes 114. Therefore, the front end of the guide wall 116 abutting against the sub-guide shaft 92 is always lower than the front end of the front guide hole 114, and the sub-guide shaft 92 can be made shorter than the main guide shaft 90 by that amount. This allows the front connection part 118 to be provided so as to cover the front side of the sub-guide shaft 92.

In the above configuration, when electricity is applied to the first coil 82 facing the first magnet 54 on the +X side surface, a Lorentz force acts on the first coil 82 in the X direction. Since the first coil 82 is fixed to the base 64, the reaction acting on the first magnet 54 becomes a driving force for the lens support 16 and the first movable body plate 22, and the lens support 16 and the first movable body plate 22 move in the X direction while being supported by the first support mechanism 36.

When current is applied to the first coil 82 facing the first magnet 54 on the -Y side surface, a Lorentz force acts on the first coil 82 in the Y direction. Because the first coil 82 is fixed to the base 64, the reaction acting on the first magnet 54 becomes a driving force for the lens support 16, and the lens support 16 moves in the Y direction while being supported by the second support mechanism 38.

After the lens support 16 has moved in at least one of the X and Y directions, the power supply to the first coil 82 is stopped. Then, due to the attractive force between the first magnet 54 and the magnetic member 86 and the friction between the first support part 40 and the first guide part 42, and between the second support part 44 and the second guide part 46, the lens support 16 stops at the position where the power supply was stopped.

Next, when electricity is applied to the second coil 84 disposed between the second magnet 58 and the magnetic member 86, a Lorentz force acts on the second coil 84 in the Z direction. Since the second coil 84 is fixed to the base 64, the reaction force acting on the second magnet 58 becomes the driving force for the moving body 14, and the moving body 14 moves in the Z direction while being supported by the optical axis direction support mechanism 88.

When the current supply to the second coil 84 is stopped after the movable body 14 has moved in the Z direction, the movable body 14 stops at the position where the current supply was stopped due to the attractive force between the second magnet 58 and the magnetic member 86 and the friction between the main guide shaft 90 and the guide hole 114, and between the sub-guide shaft 92 and the guide wall 116.
The position of the moving body 14 in the X and Y directions is detected by a position detection element 124 .

The first coil 82, the second coil 84, and the position detection element 124 are fixed to a flexible printed circuit board 78, which is fixed to a support portion 76 formed integrally with a metal support plate 100. This reduces the inclination and positional deviation of the first coil 82, the second coil 84, and the position detection element 124 relative to the first magnet 54 and the second magnet 58. This makes it possible to control the position of the moving body 14 with high precision.

The moving body 14 is supported and guided on one side in the Y direction by the main guide shaft 90 and the sub guide shaft 92. The main guide shaft 90 and the sub guide shaft 92 are firmly fixed to the metal support plate 100 by crimping the crimping portion 112, so that the tilt can be suppressed even if the front end is not fixed.

In addition, the guide walls 116, 116 that guide the secondary guide shaft 92 are connected by a front connection portion 118 and a rear connection portion 120, which improves the strength of the guide walls 116, 116, and reduces the displacement and change in inclination during the movement of the moving body 14, even if it receives an impact due to being dropped, etc.

In this embodiment, the lens driving device has a focus adjustment function and an image stabilization function, but it may have only a focus adjustment function, and can also be applied to devices that further have a zoom function. Also, although this specification describes a lens driving device used in a camera device, the present invention can be applied to other devices.

REFERENCE SIGNS LIST 10 Lens drive device 12 Fixed body 14 Movable body 16 Lens support 18 First frame 20 Lens mounting hole 22 First movable body plate 24 Second movable body plate 26 First cover 28, 30, 32 Through hole 34 Orthogonal direction support mechanism 36 First support mechanism 38 Second support mechanism 40 First support portion 42 First guide portion 44 Second support portion 46 Second guide portion 48 Mounting portion 50 Mounting hole 52 Mounted portion 54 First magnet 56 First yoke 58 Second magnet 60 Second yoke 62 Second frame 64 Base 66 Second cover 68 Bottom portion 70 Front portion 72, 74 Through hole 76 Support portion 78 Flexible printed circuit board 80 Terminal portion 82 First coil 84 Second coil 86 Magnetic member 88 Optical axis direction support mechanism 90 Main guide shaft 92 Sub guide shaft 98 Base body 100 Support plate 102 Guide shaft body portion 104 Flange portion 106 Insertion portion 108 First insertion hole 110 Second insertion hole 112 Crimp portion 114 Guide hole 116 Guide wall 118 Front connection portion 120 Rear connection portion 124 Position detection element 126 Positioning hole 128 Positioning protrusion 130 Cutout portion 132 Step portion

Claims (8)

A stationary body having a base;
a movable body having a lens support for supporting a lens;
a drive mechanism that drives the movable body relative to the fixed body,
The base includes a base body and a metal support plate provided on the base body.
The support plate is integrally formed with a support column portion that rises in the optical axis direction of the lens,
At least one component constituting the drive mechanism is fixed to a flexible printed circuit board, and the flexible printed circuit board is fixed to the support portion,
A lens driving device in which the base is formed in a rectangular shape when viewed from the optical axis direction of the lens, the support portions are provided at two sides sandwiching each of the four corners of the base, spaced apart from each other, and the flexible printed circuit board is bent at the support portions. 2. The lens driving device according to claim 1 , wherein at least one component constituting the driving mechanism is a coil or a position detection element. 2. The lens driving device according to claim 1 , wherein the support plate has a rectangular ring shape that conforms to the rectangular shape of the base, and the support pillars extend from two sides that sandwich each of four corners of the support plate. The lens driving device according to claim 1 , wherein the support portion is formed by bending a part of the support plate. The lens drive device according to claim 1, further comprising a guide shaft that guides the movement of the lens support in the direction of the optical axis of the lens, the guide shaft being fixed to the support plate. 2. The lens driving device according to claim 1 , wherein the support plate is embedded in the base body. 2. A camera device comprising: the lens drive device according to claim 1 ; and a lens supported by the lens support. An electronic device comprising the camera device according to claim 7 .