CN108761710B

CN108761710B - Actuator of camera module and camera module

Info

Publication number: CN108761710B
Application number: CN201810289063.1A
Authority: CN
Inventors: 吴皙泳; 房帝贤; 许勋; 李重锡; 沈益赞; 李泓周; 尹永复
Original assignee: Samsung Electro Mechanics Co Ltd
Current assignee: Samsung Electro Mechanics Co Ltd
Priority date: 2017-04-03
Filing date: 2018-04-03
Publication date: 2021-07-06
Anticipated expiration: 2038-04-03
Also published as: KR20180112689A; KR102115520B1; CN208172347U; KR20180112658A; CN108761710A; KR102104451B1

Abstract

The invention discloses an actuator of a camera module and the camera module. An actuator of a camera module according to an embodiment of the present invention may include: a detected part; and a position detection portion that is arranged opposite to the detected portion and includes at least two sensing coils that respectively form at least two oscillation circuits, wherein the position detection portion can detect the position of the detected portion from at least two oscillation signals having mutually different frequency ranges generated in the at least two oscillation circuits.

Description

Actuator of camera module and camera module

Technical Field

The invention relates to an actuator of a camera module and the camera module.

Background

In general, portable communication terminals such as mobile phones, PDAs, and portable PCs have recently become widespread to perform functions of transmitting not only text or voice data but also image data. In response to such a trend, a camera module is basically provided on a portable communication terminal in recent years in order to be able to perform transmission of image data, video chat, or the like.

In general, a camera module includes a lens barrel in which a lens is arranged and a housing in which the lens barrel is accommodated, and includes an image sensor for converting an image of a subject into an electric signal. The camera module may employ a single focus mode camera module that photographs an object with a fixed focus, however, with recent technological development, a camera module including an actuator capable of performing Auto Focus (AF) adjustment is employed. Meanwhile, in order to reduce the phenomenon of resolution reduction caused by hand trembling, the camera module employs an actuator that performs a hand trembling correction function (OIS).

[ Prior art documents ]

[ patent document ]

Korean laid-open patent publication No. 2013-

Disclosure of Invention

The invention provides an actuator of a camera module and a camera module, which can precisely detect the position of a magnet without adopting a Hall sensor.

An actuator of a camera module according to an embodiment of the present invention may include: a detected part; and a position detection portion that is arranged opposite to the detected portion and includes at least two sensing coils that respectively form at least two oscillation circuits, wherein the position detection portion detects a position of the detected portion from at least two oscillation signals that are generated in the at least two oscillation circuits and have mutually different frequency ranges.

A camera module according to an embodiment of the present invention may include: a lens barrel; a focus adjustment section that provides a driving force of the lens barrel in an optical axis direction; and a shake correction unit that provides driving forces in two directions perpendicular to the optical axis, wherein the focus adjustment unit and the shake correction unit generate oscillation signals whose frequencies change in accordance with movement of the lens barrel, respectively, and further detect displacement of the lens barrel, and a frequency range of the oscillation signal generated by the focus adjustment unit is different from a frequency range of the oscillation signal generated by the shake correction unit.

The actuator of the camera module according to an embodiment of the present invention can precisely detect the position of the lens barrel from the change in the inductance of the sensing coil. Further, since a separate hall sensor is not employed, the manufacturing cost of the actuator of the camera module can be saved, and the space efficiency can be improved.

Drawings

Fig. 1 is a perspective view of a camera module according to an embodiment of the present invention.

Fig. 2a is a schematic exploded perspective view of a camera module according to an embodiment of the present invention.

Fig. 2b is an expanded view of the sense and drive coils disposed on the substrate according to one embodiment of the invention.

Fig. 3 is a block diagram of a main part of an actuator employed in a camera module according to an embodiment of the present invention.

Fig. 4 is a block diagram illustrating a position detection part according to an embodiment of the present invention.

Fig. 5a and 5b show frequencies of a plurality of oscillation signals that change with movement of a detected part in the Z-axis direction according to an embodiment of the present invention.

Fig. 6a and 6b show the frequencies of a plurality of oscillation signals that change with the movement of the detected part in the X-axis direction according to an embodiment of the present invention.

Fig. 7 shows the frequencies of a plurality of oscillation signals that change with the movement of the detected part in the Y-axis direction according to an embodiment of the present invention.

Description of the symbols

110: the outer shell 120: shell body

210: the lens barrel 300: carrier

310: the frame 320 is: lens holder

400: the focus adjustment unit 500: jitter correction unit

600: substrate 700: image sensor module

1000: actuator 1100: driving part

1200: the drive coil 1300: detected part

1400: position detection unit 1410: oscillating part

1410 a: first oscillation circuit 1410 b: second oscillating circuit

1430: the calculation unit 1450: determination unit

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

However, the embodiment of the present invention may be modified into various other embodiments, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more fully explain the present invention to those having ordinary skill in the art to which the present invention pertains. The various embodiments of the invention, although different from each other, should not necessarily be understood exclusively from each other. As an example, particular shapes, structures and characteristics disclosed herein may be implemented as one embodiment without departing from the spirit and scope of the invention.

In addition, unless otherwise specifically stated to the contrary, the term "including" a certain component does not exclude other components, but means that other components may be included.

Fig. 1 is a perspective view of a camera module according to an embodiment of the present invention, fig. 2a is a schematic exploded perspective view of the camera module according to an embodiment of the present invention, and fig. 2b is an expanded view of a sensing coil and a driving coil disposed on a substrate according to an embodiment of the present invention.

Referring to fig. 1, 2a and 2b, a camera module 100 according to an embodiment of the present invention includes a lens barrel 210, an actuator moving the lens barrel 210, a housing 110 and a case 120 housing the lens barrel 210 and the actuator, and additionally, an image sensor module 700 converting light incident through the lens barrel 210 into an electrical signal.

The lens barrel 210 may be a hollow cylindrical shape such that a plurality of lenses for imaging a subject can be housed inside, and the plurality of lenses are attached to the lens barrel 210 along an optical axis. The plurality of lenses are arranged in a desired number according to the design of the lens barrel 210, and each lens has optical characteristics such as the same or different refractive index.

The actuator may move the lens barrel 210. As an example, the actuator can adjust the focus by moving the lens barrel 210 in the optical axis (Z-axis) direction, and can correct shake at the time of shooting by moving the lens barrel 210 in the direction perpendicular to the optical axis (Z-axis). The actuator includes a focus adjustment section 400 for adjusting a focus and a shake correction section 500 for correcting shake.

The image sensor module 700 may convert light incident through the lens barrel 210 into an electrical signal. As an example, the image sensor module 700 may include an image sensor 710, a printed circuit board 720 connected to the image sensor 710, and an infrared filter. The infrared filter blocks light in an infrared region from light incident through the lens barrel 210. The image sensor 710 converts light incident through the lens barrel 210 into an electrical signal. The image sensor 710 may include a Charge Coupled Device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS), as an example. The electrical signal converted by the image sensor 710 is output as an image through a display unit of the portable electronic device. The image sensor 710 is fixed to the printed circuit board 720 and electrically connected to the printed circuit board 720 by wire bonding.

The lens barrel 210 and the actuator are accommodated in the housing 120. For example, the upper and lower portions of the housing 120 are open, and the lens barrel 210 and the actuator are accommodated in the internal space of the housing 120. An image sensor module 700 is disposed at a lower portion of the housing 120.

The case 110 is combined with the case 120 in a form of surrounding the outer surface of the case 120, and can protect the internal constituent components of the camera module 100. Also, the case 110 may shield electromagnetic waves. For example, the housing 110 may shield electromagnetic waves so that the electromagnetic waves generated in the camera module do not affect other electronic components in the portable electronic device. In addition, since various electronic components are mounted on the portable electronic device in addition to the camera module, the housing 110 can shield electromagnetic waves so that the electromagnetic waves generated from the electronic components do not affect the camera module. The housing 110 may be made of a metal material and grounded to a ground pad provided on the printed circuit board 720, thereby shielding electromagnetic waves.

An actuator according to an embodiment of the present invention moves the lens barrel 210 to focus a focus on an object. As an example, the actuator includes a focus adjustment unit 400 that moves the lens barrel 210 in the optical axis (Z axis) direction.

The focus adjustment unit 400 includes a magnet 410 and a driving coil 430, and the magnet 410 and the driving coil 430 generate a driving force to move the lens barrel 210 and the carrier 300 accommodating the lens barrel 210 in the optical axis (Z axis) direction.

The magnet 410 is mounted to the carrier 300. As an example, the magnet 410 may be mounted on a surface of the carrier 300. The driving coil 430 may be mounted to the housing 120 so as to be disposed opposite to the magnet 410. For example, the driving coil 430 may be disposed on one surface of the substrate 600, and the substrate 600 is mounted to the housing 120.

The magnet 410 may be mounted on the carrier 300 to move in the optical axis (Z axis) direction together with the carrier 300, and the driving coil 430 may be fixed to the housing 120. However, according to an embodiment, the positions of the magnet 410 and the driving coil 430 may be interchanged with each other.

If a driving signal is applied to the driving coil 430, the carrier 300 may move in the optical axis (Z-axis) direction according to the electromagnetic interaction between the magnet 410 and the driving coil 430.

The lens barrel 210 is accommodated in the carrier 300, so that the lens barrel 210 is also moved in the optical axis (Z-axis) direction by the movement of the carrier 300. Further, the frame 310 and the lens holder 320 are also accommodated in the carrier 300, and the frame 310, the lens holder 320, and the lens barrel 210 are also moved in the optical axis (Z-axis) direction by the movement of the carrier 300.

In order to reduce the friction between the carrier 300 and the housing 120 when the carrier 300 moves, a rolling member B1 is disposed between the carrier 300 and the housing 120. The rolling member B1 may be in the form of a ball. The rolling members B1 may be disposed at both sides of the magnet 410.

A yoke (yoke)450 is disposed in the housing 120. For example, the yoke 450 is attached to the substrate 600 and is disposed on the case 120. The yoke 450 is disposed on the other surface of the substrate 600. Therefore, the yoke 450 is disposed to face the magnet 410 with the driving coil 430 interposed therebetween. An attractive force is generated between the yoke 450 and the magnet 410 in a direction perpendicular to the optical axis (Z-axis). Accordingly, the rolling member B1 can maintain a contact state with the carrier 300 and the case 120 by the attractive force between the yoke 450 and the magnet 410. The yoke 450 also concentrates the magnetic force of the magnet 410, thereby preventing leakage flux from occurring. For example, the yoke 450 and the magnet 410 form a Magnetic circuit (Magnetic circuit).

The present invention uses a closed-loop control method of sensing the position of the lens barrel 210 for feedback in adjusting the focus. Therefore, for closed-loop control, the focus adjustment section 400 may include a position detection section. The position detection part may include Autofocus (AF)

sensing coils

470a, 470b, and the

AF sensing coils

470a, 470b may be arranged along the optical axis (Z-axis). The inductance (inductance) of

AF sensing coils

470a, 470b varies according to the movement of magnet 410 facing

AF sensing coils

470a, 470 b. The position detecting portion may detect the position of the lens barrel 210 from a change in inductance of the

AF sensing coils

470a, 470b that occurs according to movement of the magnet 410 in the optical axis (Z-axis) direction. According to an embodiment, focus adjustment section 400 may further include a first sensing yoke 460 disposed to face

AF sensing coils

470a, 470b at one side of magnet 410. The first sensing yoke 460 may be mounted to the carrier 300 to move in the optical axis (Z-axis) direction together with the carrier 300. The first sensing yoke 460 may be formed using at least one of a conductor or a magnetic body. In the case where the first sensing yoke 460 is provided, the position detecting part may detect the position of the lens barrel 210 from a change in inductance of the

AF sensing coils

470a, 470b occurring according to movement of the first sensing yoke 460 in the optical axis (Z-axis) direction. That is, the inductance of the

AF sensing coils

470a, 470b may change according to the displacement of the magnet 410 or the first sensing yoke 460. In the case where the magnet 410 or the first sensing yoke moves in the optical axis (Z-axis) direction, the area of the magnet 410 or the first sensing yoke overlapped with the

AF sensing coils

470a, 470b is changed, and thus the inductance of the

AF sensing coils

470a, 470b may be changed.

The position detecting part of the focus adjusting part 400 may be additionally provided with at least one capacitor in order to judge the displacement of the lens barrel 210 from the change in the inductance of at least one

AF sensing coil

470a, 470 b. The at least one capacitor and

AF sensing coils

470a, 470b may form a predetermined oscillating circuit. For example, at least one capacitor is provided corresponding to the number of

AF sensing coils

470a and 470b, and one capacitor and one sensing coil may be configured in the same manner as a predetermined LC oscillator or in the same manner as a known colpitts oscillator.

The position detection section of the focus adjustment section 400 may determine the displacement of the lens barrel 210 from a change in the frequency of the oscillation signal generated in the oscillation circuit. Specifically, since the frequency of the oscillation signal generated in the oscillation circuit varies when the inductance of the

AF sensing coils

470a, 470b forming the oscillation circuit varies, the displacement of the lens barrel 210 can be detected based on the variation in the frequency of the oscillation signal.

The shake correction unit 500 is used to correct image blur or video shake caused by hand shake of a user when an image or a video is captured. For example, when a shake occurs during image capturing due to a hand shake of a user or the like, the shake correction unit 500 compensates the shake by giving a relative displacement corresponding to the shake to the lens barrel 210. For example, the shake correction unit 500 moves the lens barrel 210 in a direction perpendicular to the optical axis (Z axis) to correct shake.

The shake correction unit 500 includes a plurality of

magnets

510a and 520a and a plurality of driving

coils

510b and 520b that generate a driving force for moving the lens barrel 210 in a direction perpendicular to the optical axis (Z axis). The frame 310 and the lens holder 320 are inserted into the carrier 300 to be arranged in the optical axis (Z-axis) direction, and can guide the movement of the lens barrel 210. The frame 310 and the lens holder 320 are provided with a space into which the lens barrel 210 can be inserted. The lens barrel 210 is inserted and fixed to the lens holder 320.

The frame 310 and the lens holder 320 move in a direction perpendicular to the optical axis (Z-axis) with respect to the carrier 300 by virtue of a driving force generated by electromagnetic interaction between the plurality of

magnets

510a, 520a and the plurality of driving

coils

510b, 520 b. Of the plurality of

magnets

510a, 520a and the plurality of driving

coils

510b, 520b, the first magnet 510a and the first driving coil 510b generate a driving force in a first axis (Y axis) direction perpendicular to the optical axis (Z axis), and the second magnet 520a and the second driving coil 520b generate a driving force in a second axis (X axis) perpendicular to the first axis (Y axis). Here, the second axis (X axis) represents an axis perpendicular to the optical axis (Z axis) and the first axis (Y axis). The plurality of

magnets

510a, 520a are arranged orthogonally to each other on a plane perpendicular to the optical axis (Z-axis).

A plurality of

magnets

510a, 520a are mounted to the lens holder 320, and a plurality of driving

coils

510b, 520b facing the plurality of

magnets

510a, 520a are disposed on the substrate 600 and are further mounted to the housing 120.

The plurality of

magnets

510a, 520a may move in a direction perpendicular to the optical axis (Z-axis) together with the lens holder 320, and the plurality of driving

coils

510b, 520b may be fixed to the housing 120. However, according to an embodiment, the positions of the plurality of

magnets

510a, 520a and the plurality of driving

coils

510b, 520b may be replaced with each other.

The present invention uses a closed-loop control manner of sensing the position of the lens barrel 210 for feedback in the process of correcting the shake. Accordingly, the shake correction portion 500 may include a position detection portion for closed-loop control, and may include a second sensing yoke 530a that becomes a detected object of the shake correction portion 500. The position detection portion may include Optical Image Stabilization (OIS) sensing

coils

530b, 530c arranged along the X-axis. The second sensing yoke 530a is attached to the lens holder 320, and the OIS sensing coils 530b, 530c are disposed on the substrate 600 and are mounted to the case 120. The second sensing yoke 530a and the OIS sensing coils 530b, 530c may face in a direction perpendicular to the optical axis (Z-axis).

The inductance of the OIS sensing coils 530b, 530c varies according to the movement of the second sensing yoke 530a facing the OIS sensing coils 530b, 530 c. The position detecting part may detect the position of the lens barrel 210 from changes in inductance of the OIS sensing coils 530b, 530c occurring according to movement of the second sensing yoke 530a in two directions (X-axis direction, Y-axis direction) perpendicular to the optical axis.

In case that the second sensing yoke 530a is moved in the X-axis direction, the area of the second sensing yoke 530a overlapping the OIS sensing coils 530b, 530c is changed, so that the inductance of the OIS sensing coils 530b, 530c may be changed. In case that the second sensing yoke 530a is moved in the Y-axis direction, the distance between the OIS sensing coils 530b, 530c and the second sensing yoke 530a is changed, so that the inductance of the OIS sensing coils 530b, 530c may be changed.

The position detecting unit of the shake correcting unit 500 may be additionally provided with at least one capacitor in order to determine the displacement of the lens barrel 210 from the change in inductance of the OIS sensor coils 530b and 530 c. The at least one capacitor and the

OIS sensing coil

530b, 530c may form a predetermined oscillating circuit. For example, the at least one capacitor is provided corresponding to the number of OIS sensor coils 530b and 530c, and thus one capacitor and one sensor coil may be configured in the same manner as a predetermined LC oscillator or in the same manner as a known colpitts oscillator.

The position detection unit of the shake correction unit 500 may determine the displacement of the lens barrel 210 from the frequency change of the oscillation signal generated in the oscillation circuit. Specifically, since the frequency of the oscillation signal generated in the oscillation circuit may vary when the inductance of the OIS sensing coils 530b, 530c forming the oscillation circuit varies, the displacement of the lens barrel 210 can be detected based on the variation in the frequency of the oscillation signal.

The position detector of the shake correction unit 500 may further include a reference coil (reference coil)530d provided on one side of the OIS sensor coils 530b and 530 c. The position detection part of the shake correction part 500 may generate an oscillation signal corresponding to the inductance of the reference coil 530d, and calculate a common noise component flowing into the camera module from the frequency of the generated oscillation signal. The position detecting part of the shake correcting part 500 may remove a common noise component from the frequency of the oscillation signal calculated by the OIS sensing coils 530b, 530c, thereby improving the reliability of the displacement detection of the lens barrel 210.

In addition, the camera module 100 includes a plurality of ball members supporting the shake correction portion 500. The plurality of ball members perform a function of guiding the movement of the frame 310, the lens holder 320, and the lens barrel 210 in the process of correcting the shake. And also performs a function of maintaining the interval between the carrier 300, the frame 310, and the lens holder 320.

The plurality of ball members includes a first ball member B2 and a second ball member B3. The first ball member B2 guides the movement of the frame 310, the lens holder 320, and the lens barrel 210 in the first axis (Y-axis) direction, and the second ball member B3 guides the movement of the lens holder 320 and the lens barrel 210 in the second axis (X-axis) direction.

For example, when the first ball member B2 generates a driving force in the first axis (Y axis) direction, it performs a rolling motion in the first axis (Y axis) direction. Accordingly, the first ball member B2 guides the movement of the frame 310, the lens holder 320, and the lens barrel 210 in the first axis (Y axis) direction. When the driving force in the second axis (X axis) direction is generated, the second ball member B3 performs a rolling motion in the second axis (X axis) direction. Accordingly, the second ball member B3 guides the movement of the lens holder 320 and the lens barrel 210 in the second axis (X axis) direction.

The first ball component B2 includes a plurality of ball components disposed between the carrier 300 and the frame 310. The second ball member B3 includes a plurality of ball members arranged between the frame 310 and the lens holder 320.

The carrier 300 and the frame 310 are formed with first guide groove portions 301 for accommodating the first ball members B2 on surfaces facing each other in the optical axis (Z-axis) direction. The first guide groove portion 301 includes a plurality of guide grooves corresponding to the plurality of ball members of the first ball member B2. The first ball member B2 is accommodated in the first guide groove 301, and is interposed between the carrier 300 and the frame 310. In a state where the first ball member B2 is accommodated in the first guide groove portion 301, the movement of the first ball member B2 in the optical axis (Z axis) and second axis (X axis) directions is restricted, and the movement is only possible in the first axis (Y axis) direction. For example, the first ball member B2 may roll only in the first axis (Y axis) direction. For this reason, the planar shape of each of the plurality of guide grooves of the first guide groove portion 301 may be a rectangle having a length in the first axis (Y axis) direction.

The frame 310 and the lens holder 320 are formed with second guide groove portions 311 that accommodate the second ball members B3 on surfaces that face each other in the optical axis (Z axis) direction. The second guide groove portion 311 includes a plurality of guide grooves corresponding to the plurality of ball members of the second ball member B3.

The second ball member B3 is accommodated in the second guide groove 311, and is interposed between the frame 310 and the lens holder 320. In the state where the second ball member B3 is accommodated in the second guide groove portion 311, the movement in the optical axis (Z axis) and first axis (Y axis) directions is restricted, and the second ball member B3 can move only in the second axis (X axis) direction. For example, the second ball member B3 may roll only in the second axis (X axis) direction. For this reason, the planar shape of each of the plurality of guide grooves of the second guide groove portion 311 may be a rectangle having a length in the second axis (X-axis) direction.

In addition, in the present invention, a third ball member B4 for supporting the movement of the lens holder 320 is provided between the carrier 300 and the lens holder 320. The third ball member B4 guides the movement of the lens holder 320 in the first axis (Y-axis) direction and the movement in the second axis (X-axis) direction.

For example, when the driving force in the first axis (Y axis) direction is generated, the third ball member B4 performs the rolling motion in the first axis (Y axis) direction. Accordingly, the third ball member B4 guides the movement of the lens holder 320 in the first axis (Y axis) direction.

When the driving force in the second axis (X axis) direction is generated, the third ball member B4 performs a rolling motion in the second axis (X axis) direction. Accordingly, the third ball member B4 guides the movement of the lens holder 320 in the second axis (X axis) direction. In addition, the second ball member B3 and the third ball member B4 support the lens holder 320 in contact.

The carrier 300 and the lens holder 320 are formed with third guide groove portions 302 that accommodate the third ball members B4 on surfaces that face each other in the optical axis (Z axis) direction. The third ball member B4 is accommodated in the third guide groove 302, and is interposed between the carrier 300 and the lens holder 320. In the state where the third ball member B4 is accommodated in the third guide groove portion 302, the movement in the optical axis (Z axis) direction is restricted, and the movement can be made to roll in the first axis (Y axis) and second axis (X axis) directions. For this reason, the planar shape of the third guide groove portion 302 may be circular. Therefore, the third guide groove portion 302, the first guide groove portion 301, and the second guide groove portion 311 may have different planar shapes from each other.

The first ball member B2 can roll along the first axis (Y-axis), the second ball member B3 can roll along the second axis (X-axis), and the third ball member B4 can roll along the first axis (Y-axis) and the second axis (X-axis). Therefore, the plurality of ball members supporting the shake correction unit 500 of the present invention have different degrees of freedom. Here, the degree of freedom may mean the number of independent variables required to represent the motion state of the object in the three-dimensional coordinate system. Typically, the degree of freedom of an object in a three-dimensional coordinate system is six. The motion of the object can be represented by an orthogonal coordinate system of three directions and a rotational coordinate system of three directions. For example, in the three-dimensional coordinate system, the object can be moved in parallel along each axis (X axis, Y axis, Z axis) and can be rotated by rotational movement with reference to each axis (X axis, Y axis, Z axis).

In the present specification, the term "degree of freedom" may mean the number of independent variables required to indicate the movement of the first ball member B2, the second ball member B3, and the third ball member B4 when the power is applied to the shake correction unit 500 and the shake correction unit 500 moves by the driving force generated in the direction perpendicular to the optical axis (Z axis). For example, the third ball element B4 can perform a rolling motion along two axes (the first axis (Y-axis) and the second axis (X-axis)) by a driving force generated in a direction perpendicular to the optical axis (Z-axis), and the first ball element B2 and the second ball element B3 can perform a rolling motion along one axis (the first axis (Y-axis) or the second axis (X-axis)). Therefore, the degree of freedom of the third ball member B4 is greater than the degrees of freedom of the first ball member B2 and the second ball member B3.

When a driving force is generated in the first axis (Y-axis) direction, the frame 310, the lens holder 320, and the lens barrel 210 move together in the first axis (Y-axis) direction. Here, the first ball member B2 and the third ball member B4 perform rolling motion in the first axis (Y axis) direction. At this time, the movement of the second ball member B3 is restricted.

When a driving force is generated in the second axis (X axis) direction, the lens holder 320 and the lens barrel 210 move together in the second axis (X axis) direction. Here, the second ball member B3 and the third ball member B4 perform rolling motion in the second axis (X axis) direction. At this time, the movement of the first ball member B2 is restricted.

In addition, in the present invention, a plurality of

yokes

510c and 520c are provided to maintain the state in which the shake correction portion 500 is in contact with the first ball B2, the second ball B3, and the third ball B4. The plurality of

yokes

510c, 520c are fixed to the carrier 300, and are arranged to face the plurality of

magnets

510a, 520a in the optical axis (Z-axis) direction. Accordingly, an attractive force is generated between the plurality of

yokes

510c, 520c and the plurality of

magnets

510a, 520a in the optical axis (Z-axis) direction. Since the shake correction portion 500 receives a pressure in a direction toward the plurality of

yokes

510c and 520c by the attractive force between the plurality of

yokes

510c and 520c and the plurality of

magnets

510a and 520a, the frame 310 and the lens holder 320 of the shake correction portion 500 can maintain a state of being in contact with the first, second, and third ball members B2, B3, and B4. The plurality of

yokes

510c and 520c are made of a material that can generate attractive force with the plurality of

magnets

510a and 520 a. For example, the plurality of

yokes

510c and 520c may be provided by magnetic bodies.

The present invention provides a plurality of

yokes

510c and 520c to maintain the frame 310 and the lens holder 320 in a state of contacting the first, second, and third ball members B2, B3, and B4, and also provides a stopper (stopper)330 to prevent the first, second, and third ball members B2, B3, B4, the frame 310, and the lens holder 320 from being separated to the outside of the carrier 300 due to external impact, etc. The stopper 330 is coupled to the carrier 300 in such a manner as to cover at least a portion of the upper surface of the lens holder 320.

Fig. 3 is a block diagram of a main part of an actuator employed in a camera module according to an embodiment of the present invention. The actuator 1000 according to the embodiment of fig. 3 may correspond to the focus adjustment section 400 and the shake correction section 500 of fig. 2 a.

In the case where the actuator 1000 of fig. 3 corresponds to the focus adjustment section 400 of fig. 2a, the lens barrel may be moved in the optical axis direction in order to perform an Auto Focus (AF) function of the camera module. Accordingly, in the case where the actuator 1000 of fig. 3 performs the auto-focus function, the driving part 1100 may apply a driving signal to the driving coil 1200, thereby providing a driving force in the optical axis direction to the lens barrel.

In the case where the actuator 1000 of fig. 3 corresponds to the shake correction part 500 of fig. 2a, the lens barrel may be moved in a direction perpendicular to the Optical axis in order to perform an Optical hand shake correction (OIS) function of the camera module. Therefore, in the case where the actuator 1000 of fig. 3 performs the optical shake correction function, the driving section 1100 may apply a driving signal to the driving coil 1200, thereby providing the detected section 1300 with a driving force in a direction perpendicular to the optical axis.

The actuator 1000 according to an embodiment of the present invention may include a driving section 1100, a driving coil 1200, a detected section 1300, and a position detecting section 1400.

The driving section 1100 may generate a driving signal Sdr from an input signal Sin applied from the outside and the feedback signal Sf generated from the position detecting section 1400 and supply the generated driving signal Sdr to the driving coil 1200.

In the case where the driving signal Sdr provided by the driving section 1100 is applied to the driving coil 1200, the lens barrel may be moved in a direction perpendicular to the optical axis by means of electromagnetic interaction between the driving coil 1200 and the magnet.

The position detection section 1400 detects the position of the lens barrel moving by the electromagnetic interaction between the driving coil 1200 and the magnet through the detected section 1300, generates the feedback signal Sf, and supplies the feedback signal Sf to the driving section 1100.

The detected part 1300 may be disposed at one side of the lens barrel to move in the same direction as the moving direction of the lens barrel. The detected part 1300 provided at one side of the lens barrel may face the sensing coil of the position detecting part 1400. According to the embodiment, the detected part 1300 may be provided to a plurality of frames combined with the lens barrel in addition to the lens barrel. The detection target section 1300 may be formed of one of a magnetic material and a conductor. For example, the detected part 1300 may correspond to the magnet 410, the first sensing yoke 460 and the second sensing yoke 530a of fig. 2 a.

The position detecting part 1400 may include at least one sensing coil, and convert the inductance of the sensing coil, which varies according to the movement of the detected part 1300, into a frequency, thereby detecting the position of the detected part 1300. In this case, at least one sensor coil provided in the position detector 1400 may correspond to at least one sensor coil included in the focus adjuster 400 and the shake corrector 500 of fig. 2 a.

Fig. 4 is a block diagram illustrating a position detection part according to an embodiment of the present invention. Hereinafter, an operation of detecting the position of the detection target portion 1300 by the position detection portion 1400 will be described with reference to fig. 2a, 2b, 3, and 4.

The position detection unit 1400 according to an embodiment of the present invention may include an oscillation unit 1410, a calculation unit 1430, and a determination unit 1450.

The oscillation section 1410 may be provided with a plurality of oscillation circuits, thereby generating a plurality of oscillation signals Sosc. The plurality of oscillation circuits may include a first oscillation circuit 1410a and a second oscillation circuit 1410b, and the first oscillation circuit 1410a and the second oscillation circuit 1410b include a sensing coil and a capacitor, respectively, to constitute a predetermined LC oscillator. Specifically, first oscillation circuit 1410a may include first sensing coil L1 and first capacitor C1, and second oscillation circuit 1410b may include second sensing coil L2 and second capacitor C2. Here, the first sensing coil L1 and the second sensing coil L2 provided in the first oscillation circuit 1410a and the second oscillation circuit 1410b may correspond to the

AF sensing coils

470a and 470b included in the focus adjustment unit 400 of fig. 2a or the OIS sensing coils 530b and 530c included in the shake correction unit 500 of fig. 2 a.

The first and second sensing coils L1 and L2 can detect the displacement of the detected part 1300 facing the first and second sensing coils L1 and L2. The first and second sensing coils L1 and L2 can detect displacement of the detected part 1300 in a direction perpendicular to the plane in which the first and second sensing coils L1 and L2 are arranged. Since first sensing coil L1 and second sensing coil L2 are arranged on the same plane, the inductances of first sensing coil L1 and second sensing coil L2 can vary in the same direction according to the movement of detected portion 1300 in the direction perpendicular to the plane on which first sensing coil L1 and second sensing coil L2 are arranged. Referring to fig. 2a, in the case where the first sensing coil L1 and the second sensing coil L2 correspond to at least one

OIS sensing coil

530b, 530c included in the shake correction unit 500 of fig. 2a, the OIS sensing coils 530b, 530c can detect a displacement in the Y-axis direction of the second sensing yoke 530a disposed to face the OIS sensing coils 530b, 530 c.

Also, first and second sensing coils L1 and L2 can detect displacement of detected part 1300 in the direction in which first and second sensing coils L1 and L2 are arranged. In the case where detected part 1300 moves in the direction in which first and second sensing coils L1 and L2 are arranged, the inductances of first and second sensing coils L1 and L2 may vary in mutually different directions. Referring to fig. 2a, in the case where the first sensing coil L1 and the second sensing coil L2 correspond to at least one

OIS sensing coil

530b, 530c included in the shake correction unit 500 of fig. 2a, the OIS sensing coils 530b, 530c can detect a displacement in the X-axis direction of the second sensing yoke 530a arranged to face the OIS sensing coils 530b, 530 c. Also, in the case where the first and second sensing coils L1 and L2 correspond to the

AF sensing coils

470a and 470b included in the focus adjustment part 400 of fig. 2a, the

AF sensing coils

470a and 470b may detect displacement in the Z-axis direction of the first sensing yoke arranged to face the

AF sensing coils

470a and 470 b.

Fig. 4 schematically illustrates a first oscillation circuit 1410a and a second oscillation circuit 1410b, and the first oscillation circuit 1410a and the second oscillation circuit 1410b may be configured as oscillators of various known configurations.

The frequencies of the oscillation signals Sosc of the first and

second oscillation circuits

1410a and 1410b can be determined by the inductance of the first sensing coil L1, the inductance of the second sensing coil L2, the capacitance of the first capacitor C1, and the capacitance of the second capacitor C2. In the case where the oscillation circuit is implemented as an LC oscillation circuit composed of a sensing coil and a capacitor, the frequency f of the oscillation signal Sosc can be represented by mathematical formula 1. In equation 1, L represents the inductance of the first sensing coil L1 and the second sensing coil L2, and C represents the capacitance of the first capacitor C1 and the second capacitor C2.

[ mathematical formula 1 ]

When the detected part 1300 moves together with the lens barrel, the inductance of the first sensing coil L1 and the second sensing coil L2 can be changed because the magnetic field strength of the detected part 1300, which affects the inductance of the first sensing coil L1 and the second sensing coil L2 of the oscillation part 1410, changes. Therefore, the frequencies of the first oscillation signal Sosc1 and the second oscillation signal Sosc2 output from the first oscillation circuit 1410a and the second oscillation circuit 1410b may vary according to the movement of the detection section 1300. According to an embodiment of the present invention, in order to increase the rate of change of the inductance of the first and second sensing coils L1 and L2 based on the position movement of the detected part 1300, a magnetic substance having a high magnetic permeability may be disposed between the detected part 1300 and the oscillation part 1410.

According to an embodiment of the invention, the frequency ranges of the first oscillating signal Sosc1 and the second oscillating signal Sosc2 generated by the first oscillating circuit 1410a and the second oscillating circuit 1410b may be different from each other. For example, the frequency range of the first oscillation signal Sosc1 may correspond to a low frequency domain, and the frequency range of the second oscillation signal Sosc2 may correspond to a high frequency domain.

According to the embodiments of the present invention, two oscillation circuits arranged adjacently generate oscillation signals having different frequency ranges from each other, so that interference between the plurality of oscillation signals can be eliminated.

In order to generate oscillation signals with mutually different frequency ranges, the inductance of the first sensing coil L1 and the capacitance of the first capacitor C1 of the first oscillation circuit 1410a may be different from the inductance of the second sensing coil L2 and the capacitance of the second capacitor C2 of the second oscillation circuit 1410 b. For example, the first oscillation circuit 1410a and the second oscillation circuit 1410b may have the same inductance and different capacitance, the same capacitance and different inductance, or both the capacitance and the inductance may be different.

In addition, according to the embodiment, unlike the above, two oscillation circuits can generate oscillation signals of the same frequency band. Therefore, the inductance and capacitance of the first oscillation circuit 1410a and the second oscillation circuit 1410b can be the same.

The arithmetic unit 1430 may calculate the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc2 output from the first oscillation circuit 1410a and the second oscillation circuit 1410 b. For example, the arithmetic unit 1430 may calculate the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc2 using the reference clock CLK. Specifically, the arithmetic unit 1430 may count the first and second oscillation signals Sosc1 and Sosc2 using the reference clock CLK. The reference clock CLK is a clock signal having a very high frequency, and when the reference clock CLK is used to count the first and second oscillation signals Sosc1 and Sosc2 for one cycle in the reference interval, for example, the count value of the reference clock CLK corresponding to the first and second oscillation signals Sosc1 and Sosc2 for one cycle can be calculated. The arithmetic unit 1430 may calculate the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc2 using the count value of the reference clock CLK and the frequency of the reference clock CLK.

The determining unit 1450 may receive the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc2 from the calculating unit 1430, and determine the position of the detected unit 1300 based on the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc 2. The determination section 1450 may be equipped with a memory, and the position information of the detected section 1300 corresponding to the frequency f _ Sosc of the oscillation signal Sosc may be stored in the memory. The Memory may be implemented as a nonvolatile Memory including one of a Flash Memory (Flash Memory), an Electrically Erasable Programmable Read-Only Memory (EEPROM), and a Ferroelectric random access Memory (FeRAM).

The determination unit 1450 may determine the position of the detected section 1300 based on the position information of the detected section 1300 stored in the memory when the frequency f _ Sosc1 of the first oscillation signal Sosc1 and the frequency f _ Sosc2 of the second oscillation signal Sosc2 are transmitted from the operation unit 1430.

In the present embodiment, it is assumed that first sensing coil L1 and second sensing coil L2 correspond to

AF sensing coils

470a, 470b included in focus adjustment unit 400 of fig. 2 a. When the detected part 1300 moves in the Z-axis direction, the inductances of the first and second sensor coils L1 and L2 increase or decrease in different directions from each other. Therefore, when the detected part 1300 moves in the Z-axis direction, the directions of change in the frequencies of the first oscillation signal Sosc1 and the second oscillation signal Sosc2 generated by the first sensing coil L1 and the second sensing coil L2 may be different from each other.

Referring to fig. 5a, the frequency ranges of the first and second oscillating signals Sosc1 and Sosc2 may be different from each other. For example, the highest frequency of the second oscillation signal Sosc2 in the low frequency domain may be lower than the lowest frequency of the first oscillation signal Sosc1 in the high frequency domain.

According to an embodiment of the present invention, two oscillation circuits arranged adjacently generate oscillation signals having different frequency ranges from each other, thereby making it possible to eliminate interference between the plurality of oscillation signals. Referring to fig. 5b, unlike fig. 5a, the frequency ranges of the first and second oscillation signals Sosc1 and Sosc2 may be the same, and the frequencies of the first and second oscillation signals Sosc1 and Sosc2 may cross each other at one point.

In the present embodiment, it is assumed that the first sensing coil L1 and the second sensing coil L2 correspond to the OIS sensing coils 530b, 530c included in the shake correction section 500 of fig. 2 a. When the detected part 1300 moves in the X-axis direction, the inductances of the first sensor coil L1 and the second sensor coil L2 increase or decrease in different directions from each other. Therefore, when the detected part 1300 moves in the X-axis direction, the directions of change in the frequencies of the first and second oscillation signals Sosc1 and Sosc2 generated by the first and second sensing coils L1 and L2 may be different from each other.

Referring to fig. 6a, the frequency ranges of the first and second oscillating signals Sosc1 and Sosc2 may be different from each other. For example, the highest frequency of the second oscillation signal Sosc2 in the low frequency domain may be lower than the lowest frequency of the first oscillation signal Sosc1 in the high frequency domain.

According to an embodiment of the present invention, two oscillation circuits arranged adjacently generate oscillation signals having different frequency ranges from each other, thereby making it possible to eliminate interference between the plurality of oscillation signals. Referring to fig. 6b, unlike fig. 6a, the frequency ranges of the first and second oscillation signals Sosc1 and Sosc2 may be the same, and the frequencies of the first and second oscillation signals Sosc1 and Sosc2 may cross each other at one point.

In the present embodiment, it is assumed that the first sensing coil L1 and the second sensing coil L2 correspond to the OIS sensing coils 530b, 530c included in the shake correction section 500 of fig. 2 a. When the detected part 1300 moves in the Y-axis direction, the inductances of the first and second sensor coils L1 and L2 increase or decrease in the same direction. Therefore, when the detected part 1300 moves in the Y-axis direction, the directions of change in the frequencies of the first and second oscillation signals Sosc1 and Sosc2 generated by the first and second sensing coils L1 and L2 may be the same as each other.

Referring to fig. 7, the frequency ranges of the first and second oscillation signals Sosc1 and Sosc2 may be different from each other. In addition, the highest frequency of the second oscillation signal Sosc2 in the low frequency domain may be higher than the lowest high frequency of the first oscillation signal Sosc1 in the high frequency domain. That is, the frequencies of the first oscillation signal Sosc1 and the second oscillation signal Sosc2 may overlap in a partial frequency range.

However, the frequencies of the first and second oscillation signals Sosc1 and Sosc2 overlap in a partial frequency range, and the frequencies of the first and second oscillation signals Sosc1 and Sosc2 change in the same direction, so that interference between the plurality of oscillation signals can be eliminated.

In addition, in the above-described embodiment, although the case where the frequency ranges of the at least two oscillation signals generated by the actuator of the focus adjustment section are different from each other or the frequency ranges of the at least two oscillation signals generated by the actuator of the shake correction section are different from each other is disclosed, according to the embodiment, the frequency ranges of the at least two oscillation signals generated by the actuator of the focus adjustment section may be different from the frequency ranges of the at least two oscillation signals generated by the actuator of the shake correction section.

That is, the oscillation signals having different frequency ranges are generated in the focus adjustment section and the shake correction section, so that frequency interference between the position detection operations of the lens barrel or the detected section performed in the focus adjustment section and the shake correction section, respectively, can be eliminated, and therefore, the reliability of the position detection operation can be ensured.

In the above-described embodiment, the case where the sensing coils are provided in two is assumed, and the operation of determining the position of the magnet is described, however, the sensing coils may be provided in at least two, and the above-described manner may be applied to the sensing coils provided in at least two.

Although the present invention has been described above with reference to specific matters such as specific components and limited embodiments and drawings, these are provided only to facilitate a more complete understanding of the present invention, and the present invention is not limited to the above embodiments, and various modifications and variations can be made by those having ordinary knowledge in the art to which the present invention pertains from these descriptions.

Therefore, the idea of the present invention should not be determined by being limited to the described embodiments, and all embodiments equivalent or equivalent to the claims except the claims can be regarded as falling within the scope of the idea of the present invention.

Claims

1. An actuator of a camera module, comprising:

a detected part; and

a position detection section arranged opposite to the detected section and including at least two sensing coils forming at least two oscillation circuits, respectively,

wherein the position detecting section detects the position of the detected section based on at least two oscillation signals generated in the at least two oscillation circuits and having different frequency ranges from each other,

the frequencies of the at least two oscillation signals change according to the movement of the detected part, and the position detecting part detects the position of the detected part according to the frequencies of the at least two oscillation signals.

2. The actuator of the camera module of claim 1,

the position detection portion detects a displacement of the detected portion in a direction perpendicular to a face on which the at least two sensing coils are arranged.

3. The actuator of the camera module of claim 2,

the frequencies of the at least two oscillation signals increase and decrease in the same direction according to the movement of the detected portion.

4. The actuator of the camera module of claim 1,

the position detection portion detects a displacement of the detected portion in an arrangement direction of the at least two sensing coils.

5. The actuator of the camera module of claim 4,

the frequencies of the at least two oscillation signals increase and decrease in different directions from each other according to the movement of the detected part.

6. The actuator of the camera module of claim 1,

one of the at least two oscillation circuits generates the oscillation signal of a low frequency domain, and the other generates the oscillation signal of a high frequency domain.

7. The actuator of the camera module of claim 6,

the highest frequency of the oscillation signal in the low frequency domain is lower than the lowest frequency of the oscillation signal in the high frequency domain.

8. The actuator of the camera module of claim 1,

the at least two oscillation circuits each further include: capacitors implementing predetermined oscillators with the at least two sensing coils, respectively.

9. The actuator of the camera module of claim 8,

the frequency ranges of the at least two oscillation signals are determined according to the inductance of the sensing coils and the capacitance of the capacitors respectively provided in the at least two oscillation circuits.

10. The actuator of the camera module of claim 9,

an inductance of a sensing coil provided to one of the at least two oscillation circuits is different from an inductance of a sensing coil provided to the other oscillation circuit.

11. The actuator of the camera module of claim 9,

the capacitance of a capacitor provided in one of the at least two oscillation circuits is different from the capacitance of a capacitor provided in the other oscillation circuit.

12. A camera module, comprising:

a lens barrel;

a focus adjustment section that provides a driving force of the lens barrel in an optical axis direction; and

a shake correction section that provides driving forces in two directions perpendicular to the optical axis,

wherein the focus adjustment section and the shake correction section respectively generate at least two oscillation signals whose frequencies change in accordance with the movement of the lens barrel, and further detect the displacement of the lens barrel in accordance with the frequencies of the at least two oscillation signals,

the frequency ranges of the at least two oscillation signals generated by the focus adjustment unit are different from the frequency ranges of the at least two oscillation signals generated by the jitter correction unit.

13. The camera module of claim 12,

the frequency ranges of the at least two oscillation signals generated by the focus adjustment section are different.

14. The camera module of claim 12,

the frequency ranges of the at least two oscillation signals generated by the shake correction section are different.

15. The camera module of claim 12,

the focus adjustment unit and the shake correction unit each include an oscillation circuit that generates the oscillation signal.