Patent Description:
This application is also related to an application filed concurrently with the parent application of this application, identified by attorney docket number P31375EP1/RAB (EP application number <NUM>), entitled "Camera Module, and Position Detector and Position Detection Method Used in the Camera Module", and claiming the benefit of <CIT>.

One or more embodiments relate to a camera module, and more particularly, to a camera module capable of performing Auto Focus (AF) and optical image stabilization (OIS).

A digital camera is a device capable of storing an image of a subject as a digital file including a picture or a video image. Examples of the digital camera include a digital still camera (DSC), a digital video camera (DVC), and a digital camera module mounted in a mobile phone.

Consumers' demand for high-quality still images and/or videos has considerably increased along with the use of digital photographing apparatuses such as DSCs and/or DVCs. In particular, the demand for a camera module having an Auto Focus (AF) function for automatically adjusting a focus and an optical image stabilization (OIS) function for preventing a decrease in image sharpness due to user' handshaking has increased.

Such a camera module may include a single-axis driving unit that moves a lens barrel along an optical axis to perform an Auto Focus function and a two-axis driving unit that moves the lens barrel in a direction perpendicular to the optical axis. In other words, the camera module may include driving units for moving the lens barrel along three axes. For this purpose, a printed circuit board is used to supply current from the outside to the driving units.

When at least one of the driving units connected to the printed circuit board is moved together with the lens barrel, the printed circuit board connected to the moving driving unit is folded or unfolded. In this process, a predetermined tension variation may be generated in the printed circuit board. In particular, as the size of the camera module has become compact, the variation in tension may obstruct movement of the driving unit connected to the printed circuit board, deteriorating quality of the camera module.

<CIT> (A1) discloses a lens drive device equipped with a first supporting body that holds the lens and is movable in the direction of the optical axis, a second supporting body that holds the first supporting body, a fixed body that holds the second supporting body in a manner enabling movement in directions that are roughly orthogonal to the optical axis direction, a first drive mechanism for driving the first supporting body, a second drive mechanism for driving the second supporting body in a first direction, and a third drive mechanism for driving the second supporting body in a second direction. The first supporting body is supported by the second supporting body by means of first supporting members, which are formed from an elastic material; and the second supporting body is supported by the fixed body by means of second supporting members, which are formed from an elastic material.

<CIT> (A1) discloses an anti-shake structure for an auto-focus module includes: auto-focus module for driving a lens to move forward and rearward in a light entering path, i.e. in z-axis direction, so that the lens focuses light on an image sensor; a frame for holding the auto-focus module therein; a lens suspender with a compensation lens arranged thereon being connected to a plurality of suspension wires while the latter are connected at respective another end to the top cover plate of the frame, so that the compensation lens is correspondingly suspended in the frame in the light entering path and located behind the lens; and a shake compensation driving unit for driving the lens suspender to move horizontally in x-axis or y-axis direction, so as to compensate image shift caused by hand shaking.

<CIT> (A1) discloses an optical image stabilizer, in which a magnet and a coil are arranged such that they oppose each other. The Hall sensor is arranged such that one face thereof is opposed to one face of the magnet. The Hall sensor can easily detect the location of a group of lenses by generating a corresponding signal in response to a variation in magnetic force following a variation in the gap between magnets depending on the direction in which a group of lenses is driven, and simultaneously, in response to a variation in magnetic force that occurs when the group of lenses is displaced in the direction that intersects the direction of the gap.

According to the present invention there is provided an apparatus as set forth in the appended independent claim.

One or more embodiments disclosed herein include a camera module capable of performing an Auto Focus (AF) function and an Optical Image Stabilization (OIS) function, whereby a lens may be precisely moved, and capable of reducing or preventing a variation in a tension of a printed circuit board.

According to one or more embodiments, a camera module includes: a lens barrel including at least one lens group (which may include only a single lens); a moving frame that mounts the lens barrel and moves in an optical axis direction, and in a first direction and a second direction that are perpendicular to the optical axis direction; a fixed frame that movably supports the moving frame and provides the moving frame with a driving force in the optical axis direction, a driving force in the first direction, and a driving force in the second direction; and a base that fixes the fixed frame and includes an image sensor that is spaced apart from the at least one lens group in the optical axis direction.

The fixed frame includes a first driving coil for moving the moving frame in the optical axis direction, a second driving coil for moving the moving frame in the first direction, and third driving coils for moving the moving frame in the second direction, wherein the moving frame includes first, second, and third magnets respectively corresponding to the first, second, and third driving coils.

The camera module further includes a printed circuit board that is electrically connected to the fixed frame.

The printed circuit board supplies a current to the first, second, and third driving coils to move the moving frame.

Tension of the printed circuit board (or, more generally, a compressing and/or extending force acting on the printed circuit board as a result of movement of the moving frame) may remain constant while the moving frame moves.

The first, second, and third driving coils may be respectively spaced apart from the first, second, and third magnets in a direction perpendicular to the optical axis direction.

The first, second, and third driving coils may be disposed in sidewalls of the fixed frame.

The fixed frame may include a hole into which at least one of the first, second, and third driving coils is inserted.

The moving frame may include a groove portion into which at least one of the first, second, and third magnets is inserted.

The moving frame includes: a first moving frame that is movably supported by the fixed frame in the optical axis direction; and a second moving frame that is movably supported by the first moving frame in the first and second directions.

One or more, or a plurality of ball bearings may be disposed between the fixed frame and the first moving frame, wherein a guide groove that guides the one or more, or the plurality of ball bearings in the optical axis direction is formed in at least one of the fixed frame and the first moving frame.

One or more, or a plurality of ball bearings may be disposed between the first moving frame and the second moving frame, wherein a guide groove that guides the one or more, or the plurality of, ball bearings in the first direction or the second direction is formed in at least one of the first moving frame and the second moving frame.

The second moving frame may include: a first sub-moving frame that is moved in the first direction, wherein the second magnet is disposed at a side of the first sub-moving frame; and a second sub-moving frame that is moved in the second direction, wherein the third magnets are disposed at two sides of the second sub-moving frame.

The second sub-moving frame may be movably supported by the first sub-moving frame in the second direction, and the first sub-moving frame may be movably supported by the first moving frame in the first direction.

One or more, or a plurality, of ball bearings may be disposed between the first sub-moving frame and the second sub-moving frame, wherein a guide groove that guides the one or more, or the plurality of ball bearings in the second axis direction is formed in at least one of the first sub-moving frame and the second sub-moving frame.

One or more, or a plurality, of ball bearings may be disposed between the first sub-moving frame and the first moving frame, wherein a guide groove that guides the one or more, or plurality, of ball bearings in the first direction is formed in at least one of the first sub-moving frame and the first moving frame.

The first sub-moving frame may include a detour portion to make a detour with respect to the third magnets. The detour portion and the third magnets may be spaced apart from each other.

The first moving frame may include a yoke that is disposed to correspond to the third magnets in order to prevent the second moving frame from detaching therefrom.

The fixed frame may include first, second, and third sensors that correspond to the first, second, and third magnets, respectively.

The first, second, and third sensors may be magnetic sensors.

The first sensor may detect a position of the first magnet in the optical axis direction.

The second sensor may detect a position of the second magnet in the first direction.

The third sensors may detect a position of the third magnets in the second direction.

The third magnets may be disposed at two sides in the first direction of the second moving frame, wherein the third sensors are disposed at two sides in the first direction of the fixed frame.

A position of the moving frame in the second direction may be detected based on a first detection signal detected by one of the third sensors and a second detection signal detected by other of the third sensors.

A position of the moving frame in the second direction may be detected based on a third detection signal which is a sum of the first detection signal and the second detection signal, or more generally a position of the moving frame in the second direction may be detected based on a sum of the first detection signal and the second detection signal.

A sum of a distance between one of the third sensors and one of the third magnets in the first direction and a distance between the other of the third sensors and the other of the third magnets may be constant.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:.

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

It will be understood that, although the terms "first", "second", "third" etc. may be used herein to describe various elements, these elements should not be limited by these terms.

<FIG> is an assembly view of a camera module according to an embodiment.

Referring to <FIG>, the camera module may include a lens barrel <NUM> including at least one lens group <NUM> (which may include only a single lens), a moving frame <NUM> that mounts (or includes) the lens barrel <NUM> to move the lens barrel <NUM> in an optical axis direction (z-axis direction) and in first and second directions (x-axis and y-axis directions) that are perpendicular to the optical axis direction (z-axis), a fixed frame <NUM> that movably supports the moving frame <NUM>, and a (e.g. flexible) printed circuit board <NUM> that supplies a current to move the moving frame <NUM>. The second direction (y-axis direction) may be orthogonal to the first direction (x-axis direction), but is not limited thereto.

The moving frame <NUM> may be driven along the optical axis direction (z-axis direction), the first direction (x-axis direction), and the second direction (y-axis direction). Accordingly, an Auto Focus (AF) function of automatically adjusting a focus on an image sensor <NUM> (see <FIG>) and an optical image stabilizer (OIS) function of preventing a decrease in an image quality due to vibration such as hand shaking may be performed. The moving frame <NUM> performs the Auto Focus function by moving the lens barrel <NUM> along the optical axis direction (z-axis direction), and also performs the OIS function by moving the lens barrel <NUM> two-dimensionally along directions (x-axis direction and y-axis direction) that are perpendicular to the optical axis direction (z-axis).

The printed circuit board <NUM> provides the fixed frame <NUM> with a current for three-axis driving of the moving frame <NUM>. The printed circuit board <NUM> may drive the moving frame <NUM> along three axes by providing a current to the fixed frame <NUM>. The printed circuit board <NUM> may be a flexible printed circuit board.

If the printed circuit board <NUM> provides a current to the moving frame <NUM> and not to the fixed frame <NUM>, the printed circuit board <NUM> may be folded or unfolded while the moving frame <NUM> is moved. Accordingly, the printed circuit board <NUM> may be damaged or a tension applied to the printed circuit board <NUM> may vary. The tension variation may hinder an accurate movement of the moving frame <NUM>.

However, according to the current embodiment, the printed circuit board <NUM> provides a current not to the moving frame <NUM> but to the fixed frame <NUM>, thereby preventing folding or unfolding of the printed circuit board <NUM> due to movement of the moving frame <NUM>. As there is no tension variation in the printed circuit board <NUM>, the moving frame <NUM> may be accurately moved. More generally, then a compressing and/or extending force acting on the printed circuit board <NUM> remains constant as a result of movement of the moving frame <NUM>. Hereinafter, a structure in which an electrical connection is provided not to the moving frame <NUM> but to the fixed frame <NUM> via the printed circuit board <NUM> of the camera module will be described in detail.

<FIG> is an exploded perspective view illustrating the camera module of <FIG>. <FIG> is an exploded perspective view of the moving frame <NUM> of <FIG>, according to an embodiment. <FIG> is an exploded perspective view of the fixed frame <NUM> of <FIG>, according to an embodiment.

Referring to <FIG>, the camera module includes a base <NUM>, the fixed frame <NUM> fixed to the base <NUM>, a first moving frame <NUM> that is movably supported by the fixed frame <NUM> in an optical axis direction (z-axis direction), a second moving frame <NUM> that is movably supported by the first moving frame <NUM> in a direction perpendicular to the optical axis direction, a cover <NUM> covering an upper portion of the second moving frame <NUM>, and a printed circuit board <NUM> that is disposed at a side portion of the fixed frame <NUM>.

The base <NUM> is disposed under the fixed frame <NUM>, and an image sensor <NUM> may be included in a central portion of the base <NUM>. The lens barrel <NUM> may be spaced apart from the image sensor <NUM> in the optical axis direction (z-axis direction).

The fixed frame <NUM> is fixed to the base <NUM>. As the fixed frame <NUM> is fixed to the base <NUM>, relative positions of the fixed frame <NUM> and the base <NUM> do not vary with respect to each other. Also, the fixed frame <NUM> may be directly fixed to the base <NUM> as illustrated in <FIG>, or the fixed frame <NUM> may be indirectly fixed to the base <NUM> via another member.

The fixed frame <NUM> movably supports the moving frame <NUM>, and provides or at least facilitates the provision of a driving force to the moving frame <NUM> in the optical axis direction (z-axis direction) and in a first direction (x-axis direction) and a second direction (y-axis direction).

The fixed frame <NUM> may include first through fourth sidewalls <NUM>, <NUM>, <NUM>, and <NUM> that surround side portions of the moving frame <NUM>. The four sidewalls <NUM>, <NUM>, <NUM>, and <NUM> of the fixed frame <NUM> respectively include first and second driving coils <NUM> and <NUM> and third driving coils 130a and 130b For example, the first driving coil <NUM> for moving the first moving frame <NUM> in the optical axis direction (z-axis direction) is included in a hole 101a of the first sidewall <NUM>, the second driving coil <NUM> for moving the second moving frame <NUM> in the first direction (x-axis direction) is included in a hole 103a of the third sidewall <NUM>, and the third driving coils 130a and 130b for moving the second moving frame <NUM> in the second direction (y-axis direction) are included in holes 102a and 104a of the second and fourth sidewalls <NUM> and <NUM>. By including the third driving coils 130a and 130b in the second and fourth sidewalls <NUM> and <NUM>, the second moving frame <NUM> may be stably moved in the second direction (y-axis direction). The first and second driving coils <NUM> and <NUM> and the third driving coils 130a and 130b receive a current from the printed circuit board <NUM> to move the first and second moving frame <NUM> and <NUM>. The first and second moving frames <NUM> and <NUM> are disposed inside the fixed frame <NUM>.

The first moving frame <NUM> is moved in the fixed frame <NUM> in the optical axis direction (z-axis direction). A first magnet <NUM> may be disposed in the first moving frame <NUM> to correspond to the first driving coil <NUM>. The first magnet <NUM> includes an N-pole and an S-pole arranged along the optical axis direction (z-axis direction). The first magnet <NUM> may be a permanent magnet that generates a magnetic force without use of an additional power supply.

The first moving frame <NUM> may be movably supported by the fixed frame <NUM> in the optical axis direction (z-axis direction). One or more ball bearings B1 may be arranged between the first moving frame <NUM> and the fixed frame <NUM>. A guide groove <NUM> that guides the ball bearings B1 to be moved along the optical axis direction (z-axis direction) may be formed in at least one of the first moving frame <NUM> and the fixed frame <NUM>. The guide groove <NUM> is extended in the optical axis direction (z-axis direction), and may be used to remove or prevent a force being applied to the ball bearings B1 in another direction different from the optical axis direction (z-axis direction). Accordingly, the first moving frame <NUM> may be moved accurately in the optical axis direction (z-axis direction).

The first moving frame <NUM> may have an L-shaped cross-section. The first moving frame <NUM> includes a first region 210a that is parallel to the optical axis direction (z-axis direction) and a second region 210b that is perpendicular to the optical axis direction (z-axis direction). The first magnet <NUM> and a groove portion <NUM> into which the first magnet <NUM> is to be inserted may be formed in the first region 210a. A second region 210b movably supports the second moving frame <NUM> in a direction perpendicular to an optical axis. In the second region 210b, a yoke or other engagement element or guide <NUM> for preventing detachment of the second moving frame <NUM> therefrom may be included.

The second moving frame <NUM> is moved in a direction perpendicular to the optical axis in the fixed frame <NUM>. For example, the second moving frame <NUM> may be movably supported in the first moving frame <NUM> in a direction perpendicular to the optical axis. The second moving frame <NUM> may include a mounting portion I in which the lens barrel <NUM> may be mounted and second magnets <NUM> and third magnets 241a and 241b disposed around a circumference of the mounting portion I to respectively correspond to the second driving coils <NUM> and the third driving coils 130a, and 130b. The second magnet <NUM> includes an N-pole and an S-pole arranged in the first direction (x-axis direction) perpendicular to the optical axis. The third magnets 241a and 241b each include an N-pole and an S-pole arranged in the second direction (y-axis direction) perpendicular to the optical axis. The arrangement directions of the N-pole and the S-pole of the second magnets <NUM> and the third magnets 241a and 241b may be perpendicular to the arrangement direction of the N-pole and the S-pole of the first magnet <NUM>. According to this arrangement, the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b may be disposed at a side portion of the moving frame <NUM>, and may move the first and second moving frames <NUM> and <NUM> along three axes. The second magnet <NUM> and the third magnets 241a and 241b may each be a permanent magnet that generates a magnetic force without use of an additional power supply.

The second moving frame <NUM> may include a first sub-moving frame <NUM> and a second sub-moving frame <NUM>. The first sub-moving frame <NUM> may be movably supported by the first moving frame <NUM> in the first direction (x-axis direction). One or more ball bearings B2 may be disposed between the first sub-moving frame <NUM> and the first moving frame <NUM>. A guide groove <NUM> that guides the ball bearings B2 to move in the first direction (x-direction) may be formed in at least one of the first sub-moving frame <NUM> and the first moving frame <NUM>. The guide groove <NUM> is extended in the first direction (x-axis direction), and may remove or prevent a force being applied to the ball bearings B1 in another direction different from the first direction (x-direction). Accordingly, the first sub-moving frame <NUM> may be accurately moved along the first direction (x-direction). A groove portion <NUM> into which the second magnet <NUM> is inserted is formed in the first sub-moving frame <NUM>, and a detour portion 230a that prevents interference of the first sub-moving frame <NUM> with the third magnets 241a and 241b may also be formed in the first sub-moving frame <NUM>. When the third magnets 241a and 241b are moved in the second direction (Y-axis direction), the detour portion 230a may be spaced apart from the third magnets 241a and 241b to not obstruct movement of the third magnets 241a and 241b. For example, if the third magnets 241a and 241b are set to move about <NUM> in the second direction (y-axis direction), a distance between the detour portion 230a and the third magnets 241a and 241b may be about <NUM>.

'Detour' means that the portion 230a detours (that is extends around or about, and not across or in contact with) with respect to the magnets 241a, 241b, or a projection of the location of those magnets. That is, the detour prevents or limits physical or magnetic interference with the magnets.

The second sub-moving frame <NUM> may be movably supported by the first sub-moving frame <NUM> in the second direction (y-axis direction). One or more ball bearings B3 may be disposed between the second sub-moving frame <NUM> and the first sub-moving frame <NUM>. A guide groove <NUM> that guides the ball bearings B3 to move in the second direction (y-axis direction) may be formed in at least one of the second sub-moving frame <NUM> and the first sub-moving frame <NUM>. The guide groove <NUM> is extended in the second direction (y-axis direction), and may remove or prevent a force being applied to the ball bearings B1 in another direction different from the second direction (y-axis direction). Accordingly, the second sub-moving frame <NUM> may be accurately moved in the second direction (y-axis direction). A groove portion <NUM> into which the third magnets 241a and 241b are to be inserted may be formed in the second sub-moving frame <NUM>.

The fixed frame <NUM> is electrically connected to the printed circuit board <NUM>. Accordingly, the first, second, and third driving coils <NUM>, <NUM>, 130a, and 130b included in the fixed frame <NUM> receive a current to move the first and second moving frames <NUM> and <NUM>.

When a current is supplied to the first and second coils <NUM> and <NUM> and the third driving coils 130a, 130b, the first and second magnets <NUM> and <NUM> and third magnets 241a and 241b corresponding thereto move in a predetermined direction according to the Fleming left hand rule. When a current is supplied to the first driving coil <NUM>, the first magnet <NUM> is moved in the optical axis direction (z-axis direction). The first magnet <NUM> may be moved in a positive direction or a negative direction of the optical axis direction (z-axis direction) according to a direction that the current is supplied to the first driving coil <NUM>. When a current is supplied to the second driving coil <NUM>, the second magnet <NUM> is moved in a positive direction or a negative direction of the first direction (x-axis direction) that is perpendicular to the optical axis. When a current is supplied to the third driving coils 130a and 130b, the third magnets 241a and 241b are also moved in a positive direction or a negative direction of the second direction (y-axis direction) that is perpendicular to the optical axis.

The printed circuit board <NUM> is electrically connected to the fixed frame <NUM>. For example, a first printed circuit board <NUM> is connected to the first driving coil <NUM>, and a second printed circuit board <NUM> is connected to second driving coil <NUM> and the third driving coils 130a and 130b. First and second plates P1 and P2 for connecting the printed circuit board <NUM> to the first and second driving coils <NUM> and <NUM> and the third driving coils 130a and 130b may be disposed outside the printed circuit board <NUM>. The first plate P1 may be disposed on the outside of the first printed circuit board <NUM>, and the second plate P2 may be disposed on the outside of the second printed circuit board <NUM>. The first and second plates P1 and P2 may be formed of various materials such as stainless steel.

As described above, by disposing the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b which are not needed to be electrically connected, to the moving frame <NUM> that is moved along three axes and disposing the first and second driving coils <NUM> and <NUM> and the third driving 130a and 130b which are needed to be electrically connected, to the fixed frame <NUM> fixed to the base <NUM>, the printed circuit board <NUM> that is electrically connected to the fixed frame <NUM> does not interfere with a movement of the moving frame <NUM>. Accordingly, the moving frame <NUM> may be moved accurately. In other words, elements requiring power and/or driving elements (e.g. coils), are connected to the fixed frame <NUM>, or fed with power via the fixed frame <NUM>.

First and second sensors <NUM> and <NUM> and third sensors <NUM> and <NUM> that sense a movement of the moving frame <NUM> may be included in the first through fourth sidewalls <NUM>, <NUM>, <NUM>, and <NUM> of the fixed frame <NUM>. For example, the first sensor <NUM> is included in the first sidewall <NUM> to sense a movement of the first magnet <NUM> in the optical direction (z-axis direction) and the second sensor <NUM> is included in the third sidewall <NUM> to sense a movement of the second magnet <NUM> in the first direction (x-axis direction), and the third sensors <NUM> and <NUM> may be included in the second and fourth sidewalls <NUM> and <NUM> to sense a movement of the third magnets 241a and 241b in the second direction (y-axis direction).

The first and second sensors <NUM> and <NUM> and the third sensors <NUM> and <NUM> may be magnetic sensors that may output an electrical signal in proportion to a magnetic field of a magnet by using a Hall effect, thereby sensing a movement of the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b and the moving frame <NUM> in which the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b are installed.

The first and second sensors <NUM> and <NUM> and the third sensors <NUM> and <NUM> may detect positions of the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b used in moving the moving frame <NUM>. Accordingly, there is no need to install an additional magnet for position detection, and thus, a structure of the camera module may be simplified.

The first sensor <NUM> may determine position movement of the first magnet <NUM> in the optical axis direction (z-axis direction). <FIG> is a conceptual block diagram illustrating a first magnet and a first sensor, according to an embodiment. The principle of detecting a position of the first magnet <NUM> via the first sensor <NUM> will be briefly described with reference to <FIG>.

The first magnet <NUM> may be moved in the optical axis direction (z-axis direction). As the first magnet <NUM> is moved in the optical axis direction (z-axis direction), a distance c between a center of the first magnet <NUM> and a center of the first sensor <NUM> in the optical axis direction (z-axis direction) may vary. The first magnet <NUM> has an N-pole and an S pole arranged in the optical axis direction (z-axis direction), and thus, the first magnet <NUM> may have a predetermined magnetic flux density in the optical axis direction (z-axis direction) as shown in <FIG>. As the first magnet <NUM> is moved in the optical axis direction (z-axis direction) with respect to the first sensor <NUM>, a detection signal detected by the first sensor <NUM>, for example, a magnetic flux density, varies.

<FIG> is a graph showing a magnetic flux density detected by the first sensor <NUM> while the first magnet <NUM> that is spaced apart from the first sensor <NUM> by a predetermined distance a, for example, <NUM>, in the second direction (y-axis direction), and is moved in the optical axis direction (z-axis direction). Referring to <FIG>, a first magnetic flux density detected by using the first magnetic sensor <NUM> has a predetermined value according to the distance c between the center of the first magnet <NUM> and the center of the first sensor <NUM> in the optical axis direction (z-axis direction). For example, if the distance c between the center of the first magnet <NUM> and the center of the first sensor <NUM> along the optical axis direction (z-axis direction) is <NUM>, a first magnetic density detected by the first sensor <NUM> is <NUM> T(tesla), and if the distance c between the center of the first magnet <NUM> and the center of the first sensor <NUM> along the optical axis direction (z-axis direction) is <NUM>, a first magnetic density detected by the first sensor <NUM> may be <NUM> T. On the other hand, if the distance c between the center of the first magnet <NUM> and the center of the first sensor <NUM> along the optical axis direction (z-axis direction) is -<NUM>, the first magnetic density detected by the first sensor <NUM> may be -<NUM> T. That is, the first magnetic flux density detected by the first sensor <NUM> may be determined according to a position of the first magnet <NUM> along the optical axis direction (z-axis direction). Thus, a position of the first magnet <NUM> along the optical axis direction (z-axis direction) may be determined based on the first magnetic flux density detected by the first sensor <NUM>.

In the above description about the determination of a position of the first magnet <NUM> along the optical axis direction (z-axis direction), it is assumed that the distance a between the first magnet <NUM> and the first sensor <NUM> along the second direction (y-axis direction) is constant. Referring to <FIG> again, the first moving frame <NUM> in which the first magnet <NUM> is included is moved only in the optical axis direction (z-axis direction) with respect to the fixed frame <NUM>, in which the first sensor <NUM> is included, via the guide groove <NUM>, and thus, the distance a between the first magnet <NUM> and the first sensor <NUM> in the second direction (y-axis direction) is constant. A position movement of the first magnet <NUM> in the optical axis direction (z-axis direction) may be determined based on a magnetic flux density detected by the first sensor <NUM> which is spaced apart from the first magnet <NUM> in the second direction (y-axis direction) by a constant distance. Accordingly, the first sensor <NUM> may determine a position movement of the first moving frame <NUM>, in which the first magnet <NUM> is included, in the optical axis direction (z-axis direction).

The second sensor <NUM> may determine a position movement of the second magnet <NUM> in the first direction (x-axis direction). The first sub-moving frame <NUM> in which the second magnet <NUM> is included is moved in the first direction (x-axis direction) with respect to the first moving frame <NUM> via the guide groove <NUM>. The first sub-moving frame <NUM> is not capable of moving in the second direction (y-axis direction) with respect to the first moving frame <NUM>, and thus, a distance between the second sensor <NUM> installed in the fixed frame <NUM> and the second magnet <NUM> included in the first sub-moving frame <NUM> in the second direction (y-axis direction) is constant. The same as above, a position movement of the second magnet <NUM> in the first direction (x-axis direction) may be determined based on a magnetic flux density detected by the second sensor <NUM> which is spaced apart from the second magnet <NUM> by a constant distance in the second direction (y-axis direction). Accordingly, the second sensor <NUM> may determine a position of the first sub-moving frame <NUM> in which the second magnet <NUM> is included.

The third sensors <NUM> and <NUM> may determine a position movement of the pair of third magnets 241a and 241b in the second direction (y-axis direction). The second sub-moving frame <NUM> in which the third magnets 241a and 241b are included is moved in the second direction (y-axis direction) with respect to the first sub-moving frame <NUM> via the guide groove <NUM>. The second sub-moving frame <NUM> is not capable of moving in the first direction (x-axis direction) with respect to the first sub-moving frame <NUM>, but the first sub-moving frame <NUM> which movably supports the second sub-moving frame <NUM> may be moved in the first direction (x-axis direction) as described above. Accordingly, when the first sub-moving frame <NUM> is moved in the first direction (x-axis direction), the second sub-moving frame <NUM> is moved in the first direction, and consequently, the third magnets 241a and 241b are moved in the first direction (x-axis direction). Accordingly, the distance between the third magnet 241a the third sensor <NUM> and the distance between the third magnet 241b and the third sensor <NUM> varies.

<FIG> is a graph showing a magnetic flux density detected by the third magnetic sensor <NUM> as the third magnet 241a is moved in the second direction (y-axis direction), when the distance a between the third magnet 241a and the third sensor <NUM> varies in the first direction (x-axis direction). Referring to <FIG>, the magnetic flux density detected by the third sensor <NUM> as the third magnet 241a is moved along the second direction (y-axis direction) varies according to the distance between the third magnet 241a and the third sensor <NUM> along the first direction (x-axis direction). For example, when the distance between the third magnet 241a and the third sensor <NUM> in the first direction (x-axis direction) was <NUM>, <NUM>, <NUM>, and <NUM>, and the third magnet <NUM> has moved from the third sensor <NUM> by <NUM> in the second direction (y-axis direction), a magnetic density detected by using the third sensor <NUM> was about <NUM> T, about <NUM> T, about <NUM> T, and about <NUM> T, respectively. That is, even though the third magnet 241a is disposed at the same position along the second direction (y-axis direction), if the distance between the third magnet 241a and the third sensor <NUM> along the first direction (x-axis direction) varies, the magnetic flux density detected by the third sensor <NUM> is not constant. Accordingly, if a position of the third magnet 241a along the second direction (y-axis direction) is determined only by the magnetic flux density detected by the third sensor <NUM>, a significant error may occur.

In view of this, according to the current embodiment, the third sensors <NUM> and <NUM> that are spaced apart from each other by a predetermined distance are disposed on two sides of the pair of third magnets 241a and 241b in the first direction (x-axis direction), and a position of the third magnets 241a and 241b in the second direction (y-axis direction) may be determined based on a magnetic flux density detected by the third sensors <NUM> and <NUM>.

<FIG> is a plan view of the camera module of <FIG> illustrating the second sub-moving frame <NUM>, according to an embodiment. <FIG> are plan views that illustrate the second sub-moving frame <NUM> of <FIG> moved in the first direction (x-axis direction), according to embodiments.

Referring to <FIG>, the second sub-moving frame <NUM> mounts the lens barrel <NUM> and is moved in the first direction and the second direction. The second sub-moving frame <NUM> includes third magnets 241a and 241b disposed at two sides in the first direction (x-axis direction). The fixed frame <NUM> includes third sensors <NUM> and <NUM> spaced apart from each other in the first direction (x-axis direction) to respectively correspond to the third magnets 241a and 241b. The third sensors <NUM> and <NUM> are spaced apart from each other by a predetermined distance. When a distance between the third magnet 241a and the third sensor <NUM> in the first direction (x-axis direction) is a1, and a distance between the other third magnet 241b and the other third sensor <NUM> in the first direction (x-axis direction) is b1, the distances a1 and b1 vary according to movement of the second sub-moving frame <NUM> in the first direction (x-axis direction). However, a sum of a1 + b1 remains constant.

Referring to <FIG>, the second sub-moving frame <NUM> is moved in the first direction (x-axis direction) such that the third magnet 241a may be spaced apart from the third sensor <NUM> in the first direction (x-axis direction) by <NUM>, and the third magnet 241b may be spaced apart from the third sensor <NUM> in the first direction (x-axis direction) by <NUM>. Referring to <FIG>, the second sub-moving frame <NUM> is moved in the first direction (x-axis direction) such that the third magnet 241a may be spaced apart from the third sensor <NUM> in the first direction (x-axis direction) by <NUM>, and the third magnet 241b may be spaced apart from the third sensor <NUM> in the first direction (x-axis direction) by <NUM>.

<FIG> is a graph showing a magnetic flux density detected by the third sensors <NUM> and <NUM> of <FIG> according to positions of the third magnets 241a and 241b in the second direction (y-axis direction), and <FIG> is a graph showing a magnetic flux density detected by the third sensors <NUM> and <NUM> of <FIG> according to position of the third magnets 241a and 241b in the second direction (y-axis direction). <FIG> is a graph showing a third magnetic flux density which is a sum of first and second magnetic flux densities detected by the third sensors <NUM> and <NUM> illustrated in <FIG>, according to a position of the second sub-moving frame <NUM> in the second direction (y-axis direction), according to an embodiment.

Referring to <FIG>, according to the position of the second sub-moving frame <NUM> in the second direction (y-axis direction), patterns of the first and second magnetic flux densities detected by the third <NUM> and <NUM> vary according to distances between the third sensors <NUM> and <NUM> and the third magnets 241a and 241b in the first direction (x-axis direction). For example, a pattern of the first magnetic flux density detected by the third sensor <NUM> when the distance between the third sensor <NUM> and the third magnet 241a along the first direction (x-axis direction) is <NUM> is different from a pattern of the second magnetic flux density detected by the third sensor <NUM> when the distance between the third sensor <NUM> and the third magnet 241b in the first direction (x-axis direction) is <NUM>. Also, a pattern of the first magnetic flux density detected by the third sensor <NUM> when the distance between the third sensor <NUM> and the third magnet 241a along the first direction (x-axis direction) is <NUM> is different from a pattern of the second magnetic flux density detected by the third sensor <NUM> when the distance between the third sensor <NUM> and the third magnet 241b along the first direction (x-axis direction) is <NUM>.

However, referring to <FIG>, the third magnetic density (sum1, sum2) which is a sum of the magnetic flux densities detected by the third sensors <NUM> and <NUM> exhibit substantially the same patterns, regardless of the position of the second sub-moving frame <NUM> along the first direction (x-axis direction). The third magnetic flux density (sum1) is a sum of the first magnetic flux density detected by the third sensor <NUM> and the second magnetic flux density detected by using the third sensor <NUM> of <FIG>, and the third magnetic flux density (sum2) is a sum of the first magnetic flux density detected by the third sensor <NUM> and the second magnetic flux density detected by the third sensor <NUM> of <FIG>. The third magnetic flux density (sum1, sum2) which is a sum of the first magnetic flux density and the second magnetic flux density has a substantially constant (or, at least, substantially more constant) value regardless of a movement of the first magnet <NUM> in the first direction (x-axis direction). The third magnetic flux density (sum1, sum2) having a constant value according to a position of the third magnets 241a and 241b in the second direction (y-axis direction) means that even when the third magnets 241a and 241b are moved in the first direction (x-axis direction), an error of the third magnetic flux density detected at the same position in the second direction (y-axis direction) is less than up to <NUM>% in this embodiment.

Thus, even when the third magnets 241a and 241b are located at different positions in the first direction (x-axis direction) as illustrated in FIGS. 8A and 8B, a third magnetic flux density which is a sum of magnetic flux densities detected by the third sensor <NUM> and the third sensor <NUM> is constant according to a position of the third magnets 241a and 241b in the second direction (y-axis direction).

Accordingly, a position information generating unit (not shown) may compare the third magnetic flux density which is the sum of the first magnetic flux density detected by the third sensor <NUM> and the second magnetic flux density detected by the third sensor <NUM> with a predetermined reference value, thereby generating position information of the third magnets 241a and 241b in the second direction (y-axis direction). For example, the position information generating unit may compare the third magnetic flux density which is the sum of the first magnetic flux density detected by the third sensor <NUM> and the second magnetic flux density detected by using the third sensors <NUM> with a predetermined reference value according to the position of the third magnets 241a and 241b in the second direction (y-axis direction), thereby generating or determining position information of the third magnets 241a and 241b in the second direction (y-axis direction). As the third magnets 241a and 241b are fixed to the second sub-moving frame <NUM>, position information of the second sub-moving frame <NUM> may be generated or determined based on position information of the third magnets 241a and 241b in the second direction (y-axis direction). The reference value may be a preset value based on the third magnetic flux density in the second direction illustrated in <FIG>.

The position information generating unit may include a memory unit that stores a preset reference value according to movement of the third magnets 241a and 241b in the second direction (y-axis direction) and a position determining unit that determines position information of the third magnets 241a and 241b along the second direction (y-axis direction) by comparing the third magnetic flux density with the reference value.

A magnetic flux density is used as an example of a detection signal detected by a magnetic sensor in the current embodiment. However, an electrical signal or the like may also/alternatively be used.

Table <NUM> below shows results of a position movement of the moving frame <NUM> of the camera module of <FIG> in a positive direction or a negative direction of the second direction (y-axis direction). A current was supplied to the third driving coils 130a and 130b to move the third magnets 241a and 241b in a positive direction of the second direction (y-axis direction) nine times and in a negative direction of the second direction (y-axis direction) nine times when the moving frame <NUM> was at a reference position (Offset = <NUM>), when the moving frame <NUM> was spaced apart from the reference position a distance of +<NUM> in the first direction (x-axis direction) (Offset = +<NUM>), and when the moving frame <NUM> was spaced apart from the reference position a distance of -<NUM> in the first direction (x-axis direction) (Offset = -<NUM>), respectively. When moving the third magnets 241a and 241b in the second direction (y-axis direction), position information of the third magnets 241a and 241b in the second direction (y-axis direction) generated based on the sum of detection signals detected by the third sensors <NUM> and <NUM> was used.

Referring to Table <NUM>, even when a position of the moving frame <NUM> varies in the first direction (x-axis direction), when a predetermined current was applied to the third driving coils 130a and 130b, the moving frame <NUM> was moved uniformly within a range of about <NUM> to <NUM> which is a predetermined range in the second direction (y-axis direction). An average distance was about <NUM> to about <NUM>.

Regarding the uniform position movement of the moving frame <NUM> in the second direction (y-axis direction) as shown in Table <NUM>, it is assumed that an accurate position detection of the moving frame <NUM> takes place in the second direction (y-axis direction). Accordingly, based on the uniform position movement of the moving frame <NUM> in the second direction (y-axis direction) in a predetermined range, it may be indirectly confirmed that positions of the third magnets 241a and 241b may be accurately detected based on the sum of detection signals detected by the third sensors <NUM> and <NUM>.

<FIG> is a cross-sectional perspective view of the camera module of <FIG> cut along a line XIII-XIII'; and <FIG> is a cross-sectional perspective view of the camera module of <FIG> cut along a line XIV-XIV'.

Referring to <FIG>, the first driving coil <NUM> and the first sensor <NUM> are included in the first sidewall <NUM> of the fixed frame <NUM>, and the first magnet <NUM> is disposed in the moving frame <NUM> to correspond to the first driving coil <NUM> and the first sensor <NUM>. The first driving coil <NUM> and the first magnet <NUM> are spaced apart from each other in the second direction (y-axis direction) perpendicular to an optical axis. Also, the second driving coil <NUM> and the second sensor <NUM> are included in the third sidewall <NUM> of the fixed frame <NUM>, and the second magnet <NUM> is disposed in the moving frame <NUM> to correspond to the second driving coil <NUM> and the second sensor <NUM>. The second driving coil <NUM> and the second sensor <NUM> are also spaced apart from each other in the second direction (y-axis direction) perpendicular to the optical axis. The first driving coil <NUM> and the first sensor <NUM> are electrically connected to the first printed circuit board <NUM>, and the second driving coil <NUM> and the second sensor <NUM> are electrically connected to the second printed circuit board <NUM>.

Referring to <FIG>, the third driving coils 130a and 130b and the third sensors <NUM> and <NUM> are included the second sidewall <NUM> and the fourth sidewall <NUM> of the fixed frame <NUM>, respectively, and the third magnets 241a and 241b are disposed in the moving frame <NUM> to correspond to the third driving coils 130a and 130b and the third sensors <NUM> and <NUM>. The third driving coils 130a and 130b and the third magnets 241a and 241b are spaced apart from each other in the first direction (x-axis direction) that is perpendicular to the optical axis. The pair of the driving coils 130a and 130b and the pair of the third sensors <NUM> and <NUM> are electrically connected to the second printed circuit board <NUM>.

When a current is supplied to one of the first and second driving coils <NUM> and <NUM> and the third driving coils 130a and 130b via the first and second printed circuit boards, the first and second magnets <NUM> and <NUM> and third magnets 241a and 241b that are spaced apart from the first and second <NUM> and <NUM> and the third driving coils 130a and 130b in a direction perpendicular to the optical axis are moved in a predetermined direction. When a current is supplied to the first driving coil <NUM>, the first magnet <NUM> is moved in the optical axis direction (z-axis direction). Also, when a current is supplied to the second driving coil <NUM>, the second magnet <NUM> is moved in the first direction (x-axis direction), and when a current is supplied to the third driving coils 130a and 130b, the third magnets 241a and 241b are moved in the second direction (y-axis direction). The current may be individually or simultaneously supplied to the first and second driving coils <NUM> and <NUM> and the third driving coils 130a and 130b.

While the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b are moved, the fixed frame <NUM> to which the first and second printed circuit boards <NUM> and <NUM> are electrically connected is fixed to the base <NUM> and is not moved, and thus, tension variation of the first and second printed circuit boards <NUM> and <NUM> is not caused while the moving frame <NUM> to which the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b are mounted is moved. Accordingly, the moving frame <NUM> may be accurately moved without being affected by the tension variation applied to the first and second printed circuit boards <NUM> and <NUM>.

In addition, by spacing the first and second <NUM> and <NUM> and the third driving coils 130a and 130b apart from the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b in a direction perpendicular to the optical axis, a thickness of the camera module in the optical axis direction may be reduced. In detail, even when the first and second magnets <NUM> and <NUM> and the third magnets 241a and 241b have larger thicknesses, the thickness of the camera module in the optical axis direction may not increase.

In the above-described embodiment, the first sub-moving frame <NUM> is moved in the first direction (x-axis direction), and the second sub-moving frame <NUM> is moved in the second direction (y-axis direction), but the embodiments are not limited thereto. For example, in contrast to the above-described embodiment, the first sub-moving frame <NUM> may be moved in the second direction (y-axis direction), and the second sub-moving frame <NUM> may be moved in the first direction (x-axis direction). Also, while a voice coil motor (VCM) method in which an electromagnetic force generated between a coil and a magnet is used to drive the moving frame <NUM> is used in the above-described embodiment, other methods for driving the moving frame <NUM>, for example, an ultrasonic wave motor method using a piezoelectric element or a method of driving the moving frame <NUM> by applying a current to a shape memory alloy may also be used.

A general principle of some embodiments is thus using the sum of detected/generated signals from different sensors to generate more accurate position information. A general principle of some embodiments is thus providing a moving frame relative to a fixed frame, the fixed frame providing a driving force to the moving frame, such that movement is more accurate. In other words, drivers are not on the moving frame.

According to the camera module of the above-described embodiments, a printed circuit board is connected to a fixed frame for three-axis driving, thereby providing an Auto Focus (AF) function and an Optical Image Stabilization (OIS) function whereby a lens may be precisely moved and a tension variation in the printed circuit board may be prevented or minimized.

For the purposes of promoting an understanding of the principles of the invention, reference has been made to the preferred embodiments illustrated in the drawings, and specific language has been used to describe these embodiments.

The words "mechanism" and "element" are used broadly and are not limited to mechanical or physical embodiments, but can include software routines in conjunction with processors, etc..

The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional electronics, control systems, software development and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as "essential" or "critical".

The use of the terms "a" and "an" and "the" in the context of the present disclosure are to be construed to cover both the singular and the plural. Finally, the steps of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. Numerous modifications and adaptations will be readily apparent to those skilled in this art without departing from the scope of the present invention, as defined in the appended claims.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

All of the features disclosed in this description and drawings and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Claim 1:
An apparatus comprising:
a lens barrel (<NUM>) including at least one lens group (<NUM>);
a moving frame that mounts the lens barrel (<NUM>) and is arranged to move in an optical axis direction,
and in a first direction and a second direction that are perpendicular to the optical axis direction;
a fixed frame (<NUM>) that movably supports the moving frame and provides the moving frame with a driving force in the optical axis direction, a driving force in the first direction, and a driving force in the second direction,
wherein the moving frame includes a first moving frame (<NUM>) that is movably supported by the fixed frame (<NUM>) in the optical axis direction; and a second moving frame (<NUM>) that is movably supported by the first moving frame (<NUM>) in the first and second directions;
a base (<NUM>) that fixes the fixed frame (<NUM>), the base (<NUM>) including an image sensor (<NUM>) spaced apart from the at least one lens group (<NUM>) in the optical axis direction;
a printed circuit board (<NUM>) that is electrically connected to the fixed frame (<NUM>);
wherein the fixed frame (<NUM>) includes a first driving coil for moving the moving frame in the optical axis direction, a second driving coil for moving the moving frame in the first direction, and a third driving coil for moving the moving frame in the second direction, and
wherein the moving frame includes a first magnet, a second magnet, and a third magnet, respectively corresponding to the first, second, and third driving coils and the printed circuit board (<NUM>) is arranged to supply current to the first, second, and third driving coils for moving the moving frame.