KR20240037916A - Lens moving unit and camera module having the same - Google Patents

Abstract

The lens driving device according to this embodiment includes a bobbin on which at least one lens is installed and a coil unit is disposed on the outer peripheral surface; a housing member in which a magnet is installed at a position corresponding to the coil unit; upper and lower elastic members whose ends are respectively coupled to the upper and lower surfaces of the bobbin to elastically support movement in a direction parallel to the optical axis of the bobbin; and a sensing unit that detects movement in a direction parallel to the optical axis of the bobbin, wherein the sensing unit includes: a sensing magnet installed on the outer peripheral surface of the bobbin; and a circuit board installed on a side wall of the housing member and having a position detection sensor disposed on an inner surface facing the sensing magnet.

Description

Lens moving unit and camera module having the same {Lens moving unit and camera module having the same}

This embodiment relates to a lens driving device and a camera module equipped therewith.

The camera module includes a printed circuit board on which an image sensor that transmits electrical signals is mounted, an infrared cut-off filter that blocks light in the infrared region to the image sensor, and at least one lens that transmits an image to the image sensor. It may include an optical system consisting of. At this time, a lens driving device capable of performing an auto-focusing function and an image stabilization function may be installed in the optical system.

Lens driving devices can be configured in various ways, and voice coil unit motors are commonly used. The voice coil unit motor operates by electromagnetic interaction between a magnet fixed to a housing and a coil unit wound on the outer peripheral surface of a bobbin combined with a lens barrel to perform an auto-focusing function. This voice coil motor type actuator module can reciprocate in a direction parallel to the optical axis while the bobbin moving up and down is elastically supported by lower and upper elastic members.

Recently, in order to shorten the auto-focusing time of the camera module, there is a need to develop a lens driving device that quickly identifies the optimal focusing position by receiving feedback on the position information of the bobbin where the lens is installed. However, the instability of electromagnetic force and the lens due to magnetic force The performance of the lens driving device, such as barrel eccentricity, may deteriorate.

(Patent Document 1) KR 10-2012-0025811 A

This embodiment provides a lens driving device that can receive feedback on bobbin position information and a camera module equipped with the same.

The lens driving device according to this embodiment includes a bobbin on which at least one lens is installed and a coil unit is disposed on the outer peripheral surface; a housing member in which a magnet is installed at a position corresponding to the coil unit; upper and lower elastic members whose ends are respectively coupled to the upper and lower surfaces of the bobbin to elastically support movement in a direction parallel to the optical axis of the bobbin; and a sensing unit that detects movement in a direction parallel to the optical axis of the bobbin, wherein the sensing unit includes: a sensing magnet installed on the outer peripheral surface of the bobbin; and a circuit board installed on a side wall of the housing member and having a position detection sensor disposed on an inner surface facing the sensing magnet.

The lens driving device according to this embodiment further includes a cover member surrounding the housing member, and the cover member may include a window on a surface corresponding to the sensing magnet.

The cover member may be made of a metal material.

The bobbin may have a magnet mounting portion on which the sensing magnet is mounted to protrude from the outer circumferential surface.

The magnet mounting portion may be placed in a location that does not interfere with the coil unit.

The magnet mounting portion may be disposed above the coil unit.

The magnets may be arranged parallel to each other on two opposing sides of the housing member.

The sensing magnet and the magnet may be placed on different sides so as not to face each other.

The position sensor is a Hall sensor and may be installed on the circuit board so that a plurality of terminals are exposed to the outside.

The camera module according to this embodiment includes an image sensor; A printed circuit board on which the image sensor is mounted; and a lens driving device configured as described above.

By installing a sensing magnet on the outer surface of the bobbin, the position of the sensing magnet can be detected with a position sensor such as a hall sensor, allowing the position of the bobbin during auto focusing to be accurately determined.

Additionally, since the sensing magnet is installed on the outer surface of the bobbin, the assembly process is simple.

In addition, since an even number of magnets are arranged to face each other to control the movement of the bobbin in the optical axis direction, the electromagnetic force acting on the coil unit can be well balanced.

In addition, by forming a window in the cover member in the portion corresponding to the sensing magnet, it is possible to prevent the forward movement characteristics of the bobbin from being deteriorated due to the attractive force between the sensing magnet and the cover member.

1 is a schematic perspective view of a camera module according to this embodiment,
Figure 2 is an exploded perspective view of Figure 1;
Figure 3 is an enlarged perspective view of the bobbin of Figure 2;
Figure 4 is a front view of Figure 1;
Figure 5 is a cross-sectional view II of Figure 4, and
Figure 6 is a front view of the lens driving device with the circuit board removed according to this embodiment.

Hereinafter, the embodiment of this embodiment will be described with reference to the attached drawings.

FIG. 1 is a schematic perspective view of a camera module according to this embodiment, FIG. 2 is an exploded perspective view of FIG. 1, FIG. 3 is an enlarged perspective view of the bobbin of FIG. 2, FIG. 4 is a front view of FIG. 1, and FIG. The II-I cross-sectional view of FIG. 4 and FIG. 6 are front views of the lens driving device with the circuit board removed according to this embodiment.

As shown in FIGS. 1 and 2, the lens driving device according to this embodiment may include a base 20, a bobbin 30, and a cover member 60. The cover member 60 may form the exterior of the camera module, and as shown, a housing member 40 supporting a magnet 41, which will be described later, may be further disposed inside the cover member 60. . Hereinafter, the cover member 60 may be referred to as a 'cover'.

The base 20 may be combined with the cover member 60.

The bobbin 30 may be installed in the inner space of the cover member 60 to be movable back and forth in a direction parallel to the optical axis. The bobbin 30 may have a coil unit 31 installed on its outer peripheral surface.

The bobbin 30 may include a lens barrel 32 in which at least one lens 32a is installed, and the lens barrel 32 is located inside the bobbin 30 as shown in FIG. 2. It may also be formed to be screwable to. However, this is not limited, and although not shown, the lens barrel 32 may be directly fixed to the inside of the bobbin 30 by a method other than screwing, or the one or more lenses 32a may be installed without the lens barrel 32. It is also possible to be formed integrally with the bobbin. The lens 32a may be composed of one piece, or two or more lenses may be configured to form an optical system.

The bobbin 30 may have the above-mentioned upper and lower elastic members 51 and 52 installed at its upper and lower parts, respectively. One end of the upper elastic member 51 is connected to the bobbin 30, and the other end may be coupled to the cover member 60 or the housing member 40. When coupled to the housing member 40, the upper part of the housing member 51 is connected to the bobbin 30. It can be bonded to the surface or the bottom surface. One end of the lower elastic member 52 may be connected to the bobbin 30, and the other end may be connected to the upper surface of the base 20. In addition, a protrusion for coupling the lower elastic member 52 may be formed on the lower side of the base 20, and a hole or recess may be formed at a corresponding position of the lower elastic member 52. Through the combination, the lower elastic member 52 can be fixed and rotation can be prevented. Additionally, adhesive, etc. may be added for firm fixation.

Meanwhile, the upper elastic member 51 is composed of one body as shown in FIG. 2, and the lower elastic member 52 has a two-part structure and is provided with two springs, so that power of different polarities can be applied. That is, power applied through a terminal (not shown) is transmitted to the two springs of the lower elastic member 52, and this power can be applied to the coil unit 31 wound on the bobbin 30. To this end, the lower elastic member 52 and the coil unit 31 may be electrically connected by soldering or the like. That is, the two springs and both ends of the coil unit 31 can be electrically connected by soldering or the like. However, this is not limited, and conversely, it is possible for the upper elastic member 51 to be formed in a bipartite structure and the lower elastic member 52 to be formed as one piece.

The bobbin 30 can be supported for movement in both directions with respect to the optical axis direction by the upper and lower elastic members 51 and 52. That is, the bobbin 30 is spaced a certain distance from the base 20 and can be controlled to move upward and downward around the initial position of the bobbin 30. In addition, since the initial position of the bobbin 30 is the upper surface of the base 20, the movement of the bobbin 30 can be controlled only upward with the initial position as the center.

Meanwhile, the coil unit 31 may be provided as a ring-shaped coil block coupled to the outer peripheral surface of the bobbin 30. However, this is not limited, and the coil may be wound directly on the outer peripheral surface of the bobbin 30. As shown in FIG. 3, the coil unit 31 may be installed in a position close to the lower surface of the bobbin 30, and may include a straight surface and a curved surface depending on the shape of the bobbin 30. .

Alternatively, the coil unit 31 formed of a coil block may have a square shape or an octagonal shape. In other words, they can all be formed as straight surfaces without curved surfaces. This is in consideration of the electromagnetic action with the magnets 41 arranged oppositely. If the corresponding surface of the magnet 41 is flat, the electromagnetic force can be maximized if the face of the facing coil unit 31 is also flat. However, it is not limited to this, and depending on the design specifications, the surface of the magnet 41 and the surface of the coil unit 31 may both be curved, both flat, or one may be curved and the other may be flat.

In addition, the bobbin 30 has a first surface formed flat on a surface corresponding to the straight surface and a second surface formed rounded on a surface corresponding to the curved surface so that the coil unit 31 can be coupled to the outer peripheral surface. It may include a surface, but the second surface may also be a flat surface. At this time, a groove 33 corresponding to the inner yoke 61, which will be described later, may be formed on the upper side of the second surface, and the coil unit 31 may be placed below the groove 33, but the coil unit 31 ) may be arranged up to the vicinity of the groove (33). However, this is not limited, and a separate yoke may be provided and installed instead of the inner yoke 61.

The housing member 40 may be composed of a frame that has a substantially hexahedral shape. A coupling structure may be provided on the upper and lower surfaces of the housing member 40 to couple the upper and lower elastic members 51 and 52, respectively, and a magnet 41 may be installed on each surface. At this time, a mounting hole 42a where the magnet 41 is installed may be formed as shown in FIG. 2, but this is not limited, and the magnet 41 is directly installed on the inner peripheral surface of the housing member 40 without the mounting hole 42a. It may also be glued in place. When the magnet 41 is directly fixed to the housing member 40 in this way, the magnet 41 may be directly bonded and fixed to the side or corner of the housing member 40.

In addition, the housing member 40 may be provided with an additional through hole 42b in addition to the mounting hole 42a. A pair of through holes 42b may be formed to face each other as shown, but this is not limited. . That is, a through hole 42b larger than the size of the sensing magnet 100 may be formed on the wall of the housing member 40 facing the sensing magnet 100, which will be described later. At this time, the through hole 42b may be square, or may be provided in a circular or polygonal shape. Alternatively, the existing housing member 40 with four mounting holes 42a can be used as is, and the magnets 41 can be installed in two mounting holes 42a, and the remaining two can be used as through holes 42b. .

Additionally, unlike the embodiment, there may be only a cover member 60 without a separate housing member 40. The cover member 60 may be made of a ferromagnetic metal material such as iron. Additionally, the cover member 60 may be provided in a rectangular shape when viewed from above so as to completely cover the bobbin 30. At this time, the cover member 60 may have a square shape as shown in FIG. 1, or may be provided in an octagonal shape, although not shown. In addition, when the cover member 60 is octagonal when viewed from the top, and the shape of the magnet 41 disposed at the edge of the housing member 40 is trapezoidal when viewed from the top, the magnetic field emitted from the edge of the housing member is It can be minimized.

The cover member 60 may be integrally formed with an inner yoke 61 at a position corresponding to the receiving groove. According to this embodiment, the inner yoke 61 has one side of the coil unit 31. and may be arranged to be spaced a certain distance apart from the bobbin 30 on the other side. Additionally, the inner yoke 61 may be formed at the four corners of the housing member 40. The inner yoke 61 may be bent inward from the upper surface of the housing member 40 in a direction parallel to the optical axis. Although not shown, an escape groove may be formed in the inner yoke 61 at a position close to the bent portion. These escape grooves may be formed in pairs or symmetrically, and the bent portion where the escape grooves are formed forms a bottleneck section. Due to this escape groove formation section, when the bobbin 30 moves up and down, the inner yoke 61 and the bobbin 30 ) interference can be minimized. In other words, it is possible to prevent partial damage to the bobbin 30 due to interference with the edge of the inner yoke when the bobbin 30 moves upward. The end of the inner yoke 61 needs to be spaced apart from the bottom surface of the groove 33 at a certain distance from the reference position, which means that the inner yoke 61 is at the highest position when the bobbin 30 reciprocates. This is to prevent the end from contacting and interfering with the bottom surface of the groove 33. Additionally, the end of the inner yoke 61 may function as a stopper to regulate movement of the bobbin 30 to a section other than the design specification. Additionally, if there is no separate housing member 40, the magnet 41 may be directly bonded to the side or corner of the cover member 60. That is, the magnet 41 may be fixed to the side wall of the cover member 60 with an adhesive. Additionally, the magnetization direction of the magnet 41 may be the side facing the bobbin 30 and the side facing the cover member 60. However, this is not limited, and the magnetization direction can be changed depending on the design.

Meanwhile, the lens driving device according to this embodiment may be provided with a sensing unit to detect the movement of the bobbin 30.

The sensing unit may include a sensing magnet 100 and a position sensing sensor 210. Here, the position sensor 210 may be installed on the circuit board 200. Hereinafter, the position sensor 210 may be referred to as a 'position sensor'. Hereinafter, one of the “magnet 41” and the “sensing magnet 100” may be referred to as the “first magnet” and the other may be referred to as the “second magnet.”

The sensing magnet 100 may be smaller and thinner than the magnet 41, and may be provided in a square shape as shown. However, this is not limited, and can be configured in various shapes such as rectangular, triangular, polygonal, and circular shapes.

The sensing magnet 100 may be installed on the outer peripheral surface of the bobbin 30. According to this embodiment, it may be fixed to the magnet mounting portion 110 provided on the bobbin 30 with adhesive or the like. At this time, the magnet mounting unit 110 may include a rib-shaped guide protruding from the outer peripheral surface of the bobbin 30, but is not limited to this, and a groove in which the sensing magnet 100 can be placed may be formed. there is. The rib-shaped guide may have an opening on the lower side, as shown in FIG. 3, and may be provided to surround at least three surfaces of the sensing magnet 100. At this time, the protruding height of the guide of the magnet mounting unit 110 may correspond to the thickness of the sensing magnet 100 or may be formed to be low or high. Therefore, when the sensing magnet 100 is fixed to the magnet mounting unit 110 with adhesive or the like, the sensing magnet 100 may or may not protrude outside the guide.

Meanwhile, the sensing magnet 100 may be placed in a location that does not interfere with the coil unit 31. That is, when the coil unit 31 is installed on the lower side of the bobbin 30 as shown in FIG. 3, the sensing magnet 100 can be placed on the upper side of the coil unit 31. This is to ensure that the coil unit 31 does not affect the lifting operation of the bobbin 30 in the optical axis direction.

Additionally, as shown in FIG. 2, the sensing magnet 100 may be arranged not to face the magnet 41. That is, two magnets 41 are provided as a pair and are arranged to face each other and be parallel to each other. At this time, when the housing member 40 is provided in a square shape, the sensing magnet 100 is not installed at a position facing the two surfaces where the magnet 41 is installed. The reason for arranging the sensing magnet 100 so as not to face the magnet 41 is to prevent changes in the magnetic force of the sensing magnet 100 from interfering with the magnetic force of the magnet 41, thereby preventing the position detection sensor 210 from interfering with the magnetic force of the magnet 41. This is to ensure that the movement of the bobbin 30 can be accurately fed back.

As shown in FIG. 2 , the circuit board 200 may be disposed to correspond to each side wall of the bobbin 30, the housing member 40, and/or the cover member 60. In the case of this embodiment, a cover member 60 that functions as a shield can may be provided, and the circuit board 200 may be placed in close contact with the side wall of the cover member 60. Additionally, the circuit board 200 may be contacted and fixed to the outer or inner surface of the cover member 60, and may be formed larger than the window 300 of the cover member 60. In addition, the circuit board 200 includes a terminal 201 at one end so that it can be electrically connected to the printed circuit board 10 on which the image sensor 11, which will be described later, is mounted. In addition, in order to apply current to the coil unit 31 through the circuit board 200, the coil unit 31 is directly electrically connected to the circuit board 200, or the coil unit 31 is divided into two. After being connected to the lower spring, the two lower springs may be electrically connected to the circuit board 200 to be electrically connected to the printed circuit board 100. There are various ways to electrically connect, such as soldering, conductive epoxy, and Ag epoxy. That is, the two lower springs can be soldered directly to the circuit board 200.

At this time, since the position sensor 210, such as a hall sensor, is disposed on the inner surface of the circuit board 200, the position sensor 210 is not exposed to the outside. In addition, a window 300 is provided on the side wall of the cover member 60 corresponding to the position sensor 210, and a through hole 42b is also formed in the housing member 40, so that the position sensor 210 Can pass through the window 300 and be placed at a certain distance from the sensing magnet 100. At this time, the through hole 42b formed in the housing member 40 may be provided in a shape corresponding to the mounting portion 42a for installing the magnet 41, and may have a larger width and height than the sensing magnet 100. It may be prepared as follows. Hereinafter, “window 300” may be referred to as “opening.”

Additionally, a plurality of terminals 201 may be provided on the circuit board 200. This terminal 201 is used to apply current to the coil unit 31 while outputting a detection signal from the position sensor 210.

According to the present embodiment as described above, since the movement of the bobbin 30 in the optical axis direction can be fed back using the sensing magnet 100, the time required for the auto focusing operation can be shortened.

In addition, the device operates with the coil unit 31 wound around the bobbin 30, attaches a thin and light sensing magnet 100 to the outer wall of the bobbin 30, and detects the magnetic force of the sensing magnet 100. Since the position sensor 210 is placed in close contact with one wall of the camera module, it is possible to perform the auto-focusing function more precisely and quickly without fear of deterioration in response characteristics.

In addition, the center of the position sensor 210 and the center of the sensing magnet 100 may coincide, and the vertical length (two magnetized parts) of the sensing magnet 100 is longer than the sensing part of the position sensor 210. It can be formed long. Additionally, the sensing magnet 100 may be magnetized into two parts on a surface facing the position sensor 210, thereby enabling position detection.

In addition, the vertical length of the through hole 42b and/or the window 300 may be larger than the space of the sensing magnet 100 and/or the size of the position detection sensor 210, which moves in the vertical direction of the bobbin 30. You can.

The position detection sensor 210 can be any sensor that can detect position, such as a gyro sensor, angular velocity sensor, acceleration sensor, or photo reflector.

The camera module may include a lens driving device configured as described above, a lens barrel 32 coupled to the bobbin 30, an image sensor 11, and a printed circuit board 10. At this time, the image sensor 11 is mounted on the printed circuit board 10 and can form the bottom of the camera module.

The base 20 may additionally have an infrared cut-off filter installed at a position corresponding to the image sensor 11 and may be coupled to the housing member 40 . Additionally, the lower side of the housing member 40 can be supported. A separate terminal member may be installed on the base 20 to conduct electricity with the printed circuit board 10, and it is also possible to form the terminal integrally using surface electrodes, etc. Meanwhile, the base 20 may function as a sensor holder that protects the image sensor 11. In this case, a protrusion may be formed in the downward direction along the side of the base 20. However, this is not an essential configuration, and although not shown, a separate sensor holder may be placed at the bottom of the base 20 to perform its role.

Although embodiments according to the present embodiment have been described above, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent scope of embodiments are possible therefrom. Therefore, the true technical protection scope of this embodiment should be determined by the following patent claims.

10; printed circuit board 11; image sensor
20; base 30; bobbin
31; Coil unit 32; lens barrel
40; housing members 51, 52; Upper and lower elastic members
60; cover member 100; Sensing magnet
110; Magnet mounting part 200; circuit board
210; Position detection sensor 300; window

Claims (13)

cover;
a bobbin disposed within the cover;
A coil and a first magnet that move the bobbin; and
Includes a position sensor that detects movement of the bobbin,
The cover includes first and second side walls disposed on opposite sides of each other, and third and fourth side walls disposed on opposite sides of each other,
The position sensor is disposed closest to the first side wall among the first to fourth side walls of the cover,
A lens driving device wherein at least a portion of the position sensor does not overlap the first side wall of the cover in a direction perpendicular to the first side wall of the cover. According to paragraph 1,
The first side wall of the cover includes an opening formed at a position corresponding to the position sensor,
The lens driving device wherein the at least part of the position sensor overlaps the opening in the direction perpendicular to the first side wall of the cover. According to paragraph 1,
The first magnet is a lens driving device disposed between the bobbin and the third side wall of the cover and between the bobbin and the fourth side wall of the cover. According to paragraph 1,
Includes a circuit board disposed on the first side wall of the cover,
The position sensor is a lens driving device disposed on the inner surface of the circuit board. According to paragraph 4,
Includes a base coupled to the cover,
The circuit board includes a plurality of terminals,
A lens driving device wherein the plurality of terminals of the circuit board are exposed to a side of the base. According to paragraph 4,
Includes an elastic member coupled to the bobbin,
A lens driving device in which the elastic member is coupled to the circuit board with solder. According to paragraph 1,
A lens driving device wherein the first magnet is coupled to the cover with an adhesive. According to paragraph 1,
A lens driving device including a second magnet disposed on the bobbin. According to clause 8,
A lens driving device in which the position sensor and the second magnet are arranged to face each other. According to clause 8,
The coil is disposed on the bobbin,
The second magnet overlaps the coil in the optical axis direction,
The second magnet does not overlap the first side wall of the cover in the direction perpendicular to the first side wall of the cover. cover;
a bobbin disposed within the cover;
A coil and a first magnet that move the bobbin; and
Includes a position sensor that detects movement of the bobbin,
The cover includes first and second side walls disposed on opposite sides of each other, and third and fourth side walls disposed on opposite sides of each other,
The position sensor is disposed closest to the first side wall among the first to fourth side walls of the cover,
The first side wall of the cover includes an opening,
A lens driving device wherein at least a portion of the position sensor overlaps the opening in a direction perpendicular to the first side wall of the cover. image sensor;
A printed circuit board on which an image sensor is mounted; and
A camera module including the lens driving device of any one of claims 1 to 11. cover;
a bobbin disposed within the cover;
A coil and a first magnet that move the bobbin; and
A lens driving device including a position sensor that detects movement of the bobbin.