KR102169418B1 - Motor for actuating lens - Google Patents

Abstract

An embodiment includes a mover for fixing the lens unit, a stator supporting the mover and including a base, a lower spring disposed under the mover, and a lower spring disposed at the lower spring and disposed on the base, It provides a lens driving motor including a sensor unit that senses the position of the lens unit by a change in capacitance according to movement.

Description

Lens driving motor{MOTOR FOR ACTUATING LENS}

An embodiment of the present invention relates to a lens driving motor having an improved structure for sensing lens displacement.

With the widespread use of various portable terminals and the commercialization of wireless Internet services, demands of consumers related to portable terminals are diversifying. Accordingly, various types of additional devices are installed in the portable terminals.

Among them, a typical camera module is a camera module that can take a photograph or video of a subject, store the image data, and edit and transmit it as necessary.

Recently, the demand for small-sized camera modules is increasing for various multimedia fields such as notebook personal computers, camera phones, PDAs, smart phones, toys, etc., and also for image input devices such as information terminals of surveillance cameras and video tape recorders. .

As the number of pixels increases, these camera modules are equipped with a lens driving motor in an OIS (Optical Image Stabilization) method or AF (Auto Focusing) method. Therefore, there is a need for an improved structure for miniaturization of the camera module.

The embodiment is to consider miniaturization and provide a lens driving motor capable of accurately realizing lens position detection.

An embodiment includes a mover for fixing the lens unit, a stator supporting the mover and including a base, a lower spring disposed under the mover, and a lower spring disposed at the lower spring and disposed on the base, It provides a lens driving motor including a sensor unit that senses the position of the lens unit by a change in capacitance according to movement.

In addition, it may further include a lower spring disposed between the mover and the sensor unit, one end and the other end are respectively fastened to the stator and the mover to be electrically connected to the sensor unit.

In addition, the sensor unit may be disposed to face the lower spring.

In addition, the sensor unit may include a first plate to which a voltage is applied from the outside, and a second plate for sensing capacitance from the lower spring.

In addition, the lower spring may be formed of a leaf spring.

In addition, the lower spring may include an outer portion fastened to the stator, an inner portion fastened to the mover, and a connection portion connecting the outer portion and the inner portion to provide an elastic force.

Further, a substrate disposed under the sensor unit may be further included, and the substrate may be a flexible printed circuits board (FPCB).

In addition, the mover includes a bobbin fixing the lens unit, and an AF coil unit provided on an outer surface of the bobbin, wherein the stator includes a magnet unit disposed to correspond to an outer surface of the AF coil unit, and the magnet unit It may include a housing to be fixed, and a base that supports the housing from the lower side.

In addition, the mover includes a bobbin for fixing the lens unit, and an AF coil unit provided on an outer surface of the bobbin, wherein the stator includes a magnet unit disposed to correspond to an outer surface of the AF coil unit, and the magnet unit It may include an OIS coil unit mounted on the substrate to correspond to a lower side, a housing fixing the magnet unit, and a base supporting the housing from a lower side.

In addition, the OIS coil unit may be a fine pattern (FP) coil.

According to an exemplary embodiment of the present invention, a lens driving motor capable of miniaturization and accuracy of lens position detection is ensured including a sensing unit that senses the position of a lens using capacitance.

1 is a schematic side cross-sectional view of an AF type lens driving motor according to an embodiment of the present invention.
2 is a schematic side cross-sectional view of an OIS type (Optical Image Stabilization type) lens driving motor according to another embodiment of the present invention.
3 is a view as viewed from an upper side of a lower spring, a sensing unit, an FP coil, and an FPCB sequentially stacked according to another embodiment of the present invention.
Figure 4 is an exploded perspective view of Figure 3;

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

Unless otherwise defined, all terms in the present specification are the same as the general meanings of terms understood by those skilled in the art, and if terms used in the present specification conflict with the general meanings of the terms, the definitions used in the present specification are applied.

However, the invention to be described below is only for describing an embodiment of the present invention, not for limiting the scope of the present invention, and reference numerals used identically throughout the specification denote the same elements.

Hereinafter, referring to the drawings, a detailed description of the lens driving motor of the embodiment is as follows.

1 is a schematic side cross-sectional view of an A.F type (Auto Focusing type) lens driving motor according to an embodiment of the present invention, and FIG. 2 is a schematic side cross-sectional view of an OIS type (Optical Image Stabilization type) lens driving motor.

In addition, FIG. 3 is a view viewed from an upper side of sequentially stacking a lower spring, a sensing unit, an FP coil, and an FPCB according to another embodiment of the present invention, and FIG. 4 is an exploded perspective view of FIG. 3.

The lens driving motor according to the embodiment of the present invention may largely include a stator 100, a mover 200, a substrate 300, a lower spring 520 and a sensor unit 400, and the cover can 600 It may further include.

The difference between FIGS. 1 and 2 is a difference in a method in which the lens driving motor according to the embodiment adjusts the focus of an image by moving the bobbin and the lens unit.

Here, adjusting the focus of the image means an AF (Auto Focusing) function that moves the lens unit in the z-axis direction, which is the optical axis direction, for focusing near or far distance of the subject, or perpendicular to the z-axis direction for camera shake correction. It may mean an OIS (Optical Image Stabilization) function for moving the lens unit in the x- and y-axis directions, or a function capable of simultaneously performing the AF function and the OIS function.

That is, the actuator unit according to the embodiment of the present invention may be implemented as a lens driving motor as an AF (Auto Focusing) type as shown in FIG. 1 or as an OIS (Optical Image Stabilization) type as shown in FIG. have.

Referring to FIG. 1, in the case of an auto focusing (AF) type, the mover 200 includes a bobbin 210 fixing the lens unit, and an AF coil unit 220 provided on an outer surface of the bobbin 210 Including, the stator 100 includes a magnet portion (not shown) disposed to correspond to the outer surface of the AF coil portion 220, a housing 110 for fixing the magnet portion, and the housing 110 It may include a base 120 supported from the lower side.

The A.F coil unit 220 may be wound on the outer surface of the bobbin 210, but four individual coils may be disposed on the outer surface of the bobbin 210 at intervals of 90°. Alternatively, a pre-wound A.F coil unit 220 may be disposed on the outer surface of the bobbin. The A.F coil unit 220 may receive power applied from a printed circuit board to be described later to form an electromagnetic field.

Referring to FIG. 2, in the case of an OIS (Optical Image Stabilization) type, the mover 200 includes a bobbin 210 fixing the lens unit, and an AF coil unit 220 provided on an outer surface of the bobbin 210. ), wherein the stator 100 includes a magnet part (not shown) disposed to correspond to an outer surface of the AF coil part 220, a housing 110 fixing the magnet part, and a lower side of the magnet part It may include an OIS coil unit 130 mounted on the substrate 300 to correspond to and a base 120 supporting the housing 110 from a lower side.

The OIS coil unit 130 may be mounted on or formed on the substrate 300 provided above the base 120 to be described later, and to pass the optical signal of the lens unit (not shown) A through hole is formed in the center. On the other hand, when considering miniaturization of the camera module, specifically, lowering the height in the z-axis direction, which is the optical axis direction, the OIS coil unit 130 is a fine pattern (FP) coil 300 that is a patterned coil. Can be formed as

In short, the A.F type lens driving motor of FIG. 1 and the OIS type lens driving motor of FIG. 2 are largely in the presence or absence of the OIS coil unit 130 and the presence or absence of the side spring 530 to be described later.

1 and 2, the cover can 600 accommodates an elastic unit 500, a mover 200, a stator 100, a substrate 300, and a sensor unit 400 to be described later, 120), it is possible to form the exterior of the lens driving motor. Specifically, the cover can 600 may be mounted on the base 120 so that the inner surface thereof is in close contact with the side surface of the base 120 to be described later, and at this time, the internal components are protected from external impacts and external contamination It may have a substance penetration prevention function.

In addition, the cover can 600 may also perform a function of protecting components of the camera module from external radio wave interference generated by a mobile phone or the like, and the cover can 600 may be formed of a metal material.

The cover can 600 may be implemented as a yoke unit to be described later, or may be fixed by molding the yoke unit inside. In an embodiment, an upper side of the cover can 600 has an opening through which a lens unit (not shown) is exposed, and an inner yoke formed bent inside the cover can 600 at a lower end of the upper side of the cover can 600 Can be formed. This inner yoke may be positioned between the bobbin 210 to be described later and the A.F coil unit 220 wound around the bobbin 210.

1 and 2, the lens unit (not shown) may be a lens barrel, but is not limited thereto, and any holder structure capable of supporting a lens may be included. In the embodiment, a case where the lens unit is a lens barrel is described as an example.

The lens unit (not shown) is installed on an upper side of a printed circuit board to be described later, and is disposed at a position corresponding to an image sensor (not shown). One or more lenses are provided in the lens unit.

1 and 2, the bobbin 210 is coupled to the lens unit to fix the lens unit, and the coupling method of the lens unit and the bobbin 210 is a thread as shown in the inner peripheral surface of the bobbin 210 The screw thread coupling method formed respectively on the outer circumferential surface of the lens unit and the lens unit may be used, but may also be joined by a screwless method using an adhesive. Of course, even in the threaded connection method, it is also possible to achieve a more robust mounting with each other by using an adhesive after threading.

1 and 2, the magnet part (not shown) is a housing 110 to be described later so that it may be disposed to correspond to the outer surface of the AF coil part 220 and the upper surface of the OIS coil part 130. ) Is mounted with an adhesive or the like, and is mounted at equal intervals at four corners or four sides inside the housing 110 to promote efficient use of the internal volume. 1 and 2, the magnet part is cut from the opposite side in the structure in which the magnet part is disposed at the four corners of the housing 110, and the magnet part is not shown.

The shape of the one or more magnets constituting the magnet part may be in the shape of each pillar, such as a triangular pillar shape, a square pillar shape, a trapezoidal pillar shape, and so on, and may include some curves in each pillar shape. The magnet part may include a curved surface required for processing at the edge of the magnet part, or if the shape of the coil unit is circular, the magnet part facing the coil unit in order to maximize the size of the magnetic flux between the coil unit and the magnet part. Shaving can be formed into a curved surface.

1 and 2, the housing 110 has a shape corresponding to the inner surface of the cover can 600 forming the exterior of the camera module, and may be spaced apart from the cover can 600 by a predetermined distance. . In an embodiment, the housing 110 is formed in a hexahedral shape corresponding to the shape of the cover can 600, and the upper and lower sides are open.

In addition, the housing 110 may include a magnet part fastening hole or fastening groove formed in a shape corresponding to the magnet part at a side or corner.

In addition, the housing 110 is formed of an insulating material and may be formed as an injection product in consideration of productivity, and the housing 110 is a moving part for driving OIS and is spaced a predetermined distance from the cover can 600 and 100 Can be deployed.

Referring to FIG. 2, the substrate 300 may be disposed under the mover 200 to apply power to the A.F coil unit 220 of the mover 200. Here, power may be applied because the substrate 300 and the coil are electrically connected through a side spring 530 to be described later. Such a substrate 300 may be applied as an FPCB (300, Flexible Printed Circuit Board), and is disposed on the upper side of the base 120 to apply power to the OIS coil unit 130 and the sensor unit 400 to be described later. It may be, and a through hole corresponding to the through hole of the OIS coil unit 130 is formed. In addition, in the case of FIG. 1, power may be applied to the AF coil unit through the lower plate spring.

The elastic unit 500 is disposed above and below the mover 200, and one end and the other end are respectively fastened to the stator 100 and the mover 200 to be electrically connected to the sensor unit. The lower spring 520 may be formed of an elastic unit 500, that is, a leaf spring.

Here, the elastic unit 500 may include an upper spring 510, a lower spring 520, and a side spring 530.

The upper spring 510, the lower spring 520, and the side spring 530 may be formed of separate springs disposed at each side of the housing 110. In the embodiment, the upper spring is divided into two. , The substrate 300 and the side spring 530, the side spring 530 and the upper spring 510 are electrically connected. In addition, since the lower spring 520 is divided into two, the substrate 300 and the lower spring 520 may be electrically connected. .

1 and 2, the inner portions 512 and 522 of the upper spring 510 and the lower spring 520 are formed in a substantially circular shape so as to be fastened to the movable portion, and the outer portions 511 and 521 are the stator ( 100) in the housing 110 and/or the base 120 is formed in an approximately square shape so that it can be fastened. The outer portions 511 and 521 and the inner portions 512 and 522 are connected by connecting portions 513 and 523, and the connecting portions 513 and 523 may be formed by bending one or more times to provide an elastic force.

2, the side spring 530 has one end and the other end fastened to the housing 110 and the base 120, and can be implemented as a substantially rectangular plate spring, and various modifications such as a wire spring or a coil spring Springs are also possible.

The upper spring 510, the lower spring 520, or the side spring 530 may be electrically connected to each other to transmit power applied from a printed circuit board to be described later to the A.F coil unit 220.

1 and 2, the base 120 supports the stator 100 and the housing 110, and can perform a sensor holder function to protect an image sensor (not shown) to be described later, and IR It may be provided to place a filter (not shown).

In this case, the IR filter may be mounted in a through hole formed in the center of the base 120, and an infrared ray filter may be provided. In addition, the IR filter may be formed of, for example, a film material or a glass material, and an infrared blocking coating material may be disposed on a flat optical filter such as a cover glass or cover glass for protecting an imaging surface. In addition, a separate sensor holder may be positioned under the base 120 in addition to the base 120.

In addition, the base 120 may be formed with one or more fixing protrusions 121 protruding from the upper edge and interfacing with the inner surface of the cover can 600 or coupling, and such fixing protrusions 121 It is possible to easily guide the fastening of the can 600 and at the same time enable solid fixation after fastening. In addition, a protrusion is formed along the side of the base under the base to function as a sensor holder. In this case, a separate sensor holder may not be required.

1 to 4, the embodiment includes a sensor unit 400 for detecting a positional movement of the lens unit, such a sensor unit 400 may be disposed under the mover 200, It may be disposed on the base. The base may have a groove portion for disposing the sensor unit 400, and the sensor unit 400 may be disposed in the groove portion. In addition, a separate substrate 300 may be disposed on the base, which may be disposed in a groove formed in the base. The sensor unit 400 may be electrically connected to the substrate 300 and may be disposed on the substrate 300.

The sensor unit disposed on the substrate 300 may be disposed in the groove, or may be disposed to protrude from an upper surface of the groove. In addition, the sensor unit may be electrically connected to the printed circuit board of the camera module, may be directly connected, or may be connected through the substrate 300.

Accordingly, the sensor unit is electrically connected to the printed circuit board and detects the position of the lens unit by a change in capacitance according to the movement of the mover 200.

The sensor unit 400 is disposed to face the lower spring 520. The sensor unit is separated from and insulated from the lower spring 520. Specifically, the sensor unit 400 is electrically connected to the printed circuit board of the camera module, the first plate 410 for transmitting the power applied from the printed circuit board to the lower spring 520, the It is electrically connected to the printed circuit board of the camera module, and may include a second plate 420 for sensing a capacitance between the lower spring 520 and the first plate 410. The first plate 410 may be a capacitive driving plate, and the second plate 420 may be a capacitive sensing plate.

In addition, the sensor unit may include only the first plate 410, and in this case, the lower spring 520 may function as the second plate 420 for sensing capacitance. That is, when the sensor unit is composed of only the first plate 410, the lower spring 520 may be a capacitance sensing plate.

Capacitance (C) refers to an amount representing the degree of the ability of the object to accumulate electric charges (electrical quantities) when applying electric charges (Q) to an insulated object. This capacitance C is proportional to the area A of the object and inversely proportional to the distance d. Using these characteristics, it is possible to calculate the displacement according to the movement of the stator 100.

The embodiment has been described in the form of a separate substrate 300 under the sensor unit, and the substrate 300 may be an FPCB. Each of the first plate 410 and the second plate 420 formed of the conductor is electrically connected to the substrate 300. The voltage applied by the substrate 300 changes the capacitance between the lower spring 520 and the second plate through the first plate 410 electrically connected to the substrate 300, and the lower spring 520 ), the capacitance of the lower spring 520 may be sensed through the second plate 420 that is disposed to face and is spaced apart and insulated from each other. In addition, when the second plate 420 is not separately provided, the first plate 410 spaced apart and insulated from the lower spring 520 and disposed oppositely is electrically connected to the printed circuit board of the camera module. Voltage is applied, and as the lower spring 520 moves up and down, the capacitance between the lower spring 520 and the first plate 410 is sensed through the lower spring 520 and the lower spring ( Since the movement amount of the 520 can be detected, the position of the lower spring 520 and the fixed bobbin 210 can be detected.

Here, in the lower spring 520, since the inner portions 512 and 522 are moved by the movement of the movable member 200, variations in the area and/or distance facing the sensor unit 400 occur, resulting in a power failure. The capacity becomes variable. For example, when the mover 200 is moved upward along the optical axis direction, the sensor unit 400 and the distance d become farther, thereby reducing the capacitance. The second plate 420 detects this, and the substrate 300 or a printed circuit board to be described later can finally calculate the moving position of the mover 200.

On the other hand, the lens driving motor according to the embodiment may be mounted on a camera module, and such a camera module includes a variety of multimedia fields such as mobile phones or notebook personal computers, camera phones, PDAs, smarts, toys, etc. It may be provided in an image input device such as an information terminal of a camera or video tape recorder.

In short, when the lens driving motor according to the embodiment is provided in the camera module, the camera module is not shown, but may further include a printed circuit board, an IR filter, an image sensor, and the like.

The printed circuit board (not shown) has an image sensor (not shown) mounted in the center of the upper side, and various devices (not shown) for driving the camera module may be mounted. In addition, the printed circuit board is to apply power to drive the lens driving motor according to the embodiment, through the terminal portion or the lower spring 520 or the upper spring 510 or the substrate 300 or directly, the AF It may be electrically connected to the coil unit 220

The image sensor (not shown) may be mounted in the center of the upper side of the printed circuit board so that it can be positioned along the optical axis direction with one or more lenses (not shown) accommodated in the lens unit. Such an image sensor converts an optical signal of an object incident through the lens into an electrical signal.

The lens driving motor or camera module according to this implementation includes a sensor unit 400 using capacitance, and the sensor unit 400 includes a first plate 410 and a second plate 420 or a second plate having a thin plate shape. Since it can be implemented only with 1 plate 410, it occupies a small space compared to a lens driving motor using a conventional Hall sensor type or a photo reflect type, and thus a lens driving motor or a camera Miniaturization and slimming of the module can be implemented.

From the above description, those skilled in the art will recognize that various changes and modifications can be made without departing from the technical spirit of the present invention, and the technical scope of the present invention is not limited to the contents described in the embodiments, but claims It should be determined according to the scope and the scope equivalent thereto.

100: stator 110: housing
120: base 200: mover
210: bobbin 220: coil unit
220: AF coil unit 130: OIS coil unit
300: substrate 400: sensor unit
410: first plate 420: second plate
500: elastic unit 510: upper spring
520: lower spring 530: side spring
600: cover can

Claims (10)

A cover including an upper plate and a side plate extending from the upper plate;
A housing disposed within the cover;
A bobbin disposed in the housing;
A base disposed under the housing;
An AF coil unit disposed on an outer surface of the bobbin;
A magnet portion disposed in the housing and facing the AF coil portion;
A lower spring connecting the bobbin and the housing;
A substrate disposed on the base; And
And a sensor part disposed between the lower spring and the substrate to face the lower spring,
The AF coil unit overlaps at least a portion of the sensor unit in the optical axis direction,
The sensor unit detects the movement of the bobbin in the optical axis direction,
The sensor unit is spaced apart from the lower spring,
A lens driving motor whose total capacitance sensed by the sensor unit is varied in proportion to a distance between the sensor unit and the lower spring. The method of claim 1,
The sensor unit includes a protrusion protruding from an outer surface of the sensor unit,
The protrusion portion of the sensor unit includes a first area protruding from the outer surface of the sensor unit in a first direction, and a second area bent from the first area in a second direction different from the first direction,
A lens driving motor in which the second region of the protruding part of the sensor part is in contact with the substrate. The method of claim 1,
The lower spring includes an inner portion coupled to a lower surface of the bobbin, an outer portion disposed outside the inner portion, and a connection portion connecting the inner portion and the outer portion,
When the bobbin moves in the direction of the optical axis, the capacitance sensed by the sensor is variable in inverse proportion to the area of the inner portion of the lower spring that is coupled to the lower surface of the bobbin delete The method of claim 1,
The sensor unit includes a first plate and a second plate spaced apart from the first plate,
The first plate transmits power applied to the substrate to the lower spring,
The second plate is a lens driving motor for sensing a capacitance between the first plate and the lower spring. The method of claim 5,
The first and second plates are a lens driving motor formed of a conductor. The method of claim 1,
And an OIS coil part disposed on the substrate and facing the magnet part,
A lens driving motor wherein the OIS coil unit is formed of a patterned coil. The method of claim 1,
The lower spring is a leaf spring, a lens driving motor. Image sensor;
The lens driving motor of claim 1;
A camera module including a lens coupled to the bobbin of the lens driving motor. A portable terminal comprising the camera module of claim 9.

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