KR20190123651A - Camera module - Google Patents

Abstract

A camera module according to an embodiment of the present invention may include a lens barrel, a driving coil disposed to be opposite to a to-be-detected part provided at one side of the lens barrel, a driving device for providing a driving signal to the driving coil, and a position calculation part which includes a first capacitor for providing ground for an alternating current signal to the driving coil, a second capacitor coupled to the driving coil and constituting the driving coil and an oscillation circuit, and a position calculation circuit for calculating the position of the lens barrel from the frequency of the oscillating circuit. The position of a magnet can be detected precisely.

Description

Camera Module {CAMERA MODULE}

The present invention relates to a camera module.

BACKGROUND ART In general, portable communication terminals such as mobile phones, PDAs, portable PCs, and the like, have recently generalized to transmit image data as well as text or voice data. In order to respond to this trend, in order to enable video data transmission, video chat, and the like, camera modules are basically installed in portable communication terminals in recent years.

In general, the camera module includes a lens barrel having a lens therein and a housing accommodating the lens barrel therein and includes an image sensor for converting an image of a subject into an electrical signal. The camera module may employ a short-focus camera module that photographs an object by a fixed focus, but recently, a camera module including an actuator capable of autofocus (AF) adjustment has been adopted according to technology development. In addition, the camera module employs an actuator for an optical image stabilization (OIS) to reduce the resolution degradation caused by the camera shake.

Republic of Korea Patent Publication No. 2013-0077216

An object of the present invention is to provide a camera module that can accurately detect the position of a magnet without employing a hall sensor.

According to an embodiment of the present invention, a camera module includes a lens barrel, a driving coil disposed to face the detection unit provided at one side of the lens barrel, a driving device providing a driving signal to the driving coil, and an alternating current to the driving coil. A first capacitor providing ground for a signal, a second capacitor connected to the drive coil to form an oscillation circuit, and a position calculation circuit calculating a position of the lens barrel from a frequency of the oscillation circuit; It may include a position calculation unit.

Since the actuator of the camera module according to an embodiment of the present invention does not employ a separate hall sensor, the manufacturing cost of the actuator of the camera module can be reduced and space efficiency can be improved.

1 is a perspective view of a camera module according to an embodiment of the present invention.
2 is a schematic exploded perspective view of a camera module according to an embodiment of the present invention.
3 is a block diagram of an actuator employed in a camera module according to an embodiment of the present invention.
4 is a view showing in detail the main part of the actuator of FIG.
5 is a view illustrating in detail a driving circuit part of the driving apparatus of FIG. 4.
6 is a circuit diagram of a driving circuit unit and a position calculator according to an embodiment of the present invention.
7 shows an equivalent circuit of the circuit of FIG. 6 for a direct current signal.
8-11 show an equivalent circuit of the circuit of FIG. 6 for an alternating signal.
12 is a block diagram of a frequency sensing unit according to an embodiment of the present invention.

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

However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be embodied in other embodiments without departing from the spirit and scope of the invention in connection with one embodiment.

In addition, "including" a certain component means that it may further include other components, without excluding other components, unless specifically stated otherwise.

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

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

The lens barrel 210 may have a hollow cylindrical shape so that a plurality of lenses for photographing a subject may be accommodated therein, and the plurality of lenses are mounted on the lens barrel 210 along the optical axis. The plurality of lenses are arranged as many as necessary according to the design of the lens barrel 210, each lens has the same or different optical properties, such as refractive index.

The actuator may move the lens barrel 210. For example, the actuator can adjust the focus by moving the lens barrel 210 in the optical axis (Z axis) direction, and corrects the shake during shooting by moving the lens barrel 210 in the direction perpendicular to the optical axis (Z axis). can do. The actuator includes a focus adjuster 400 for adjusting focus and a shake corrector 500 for correcting shake.

The image sensor module 700 may convert light incident through the lens barrel 210 into an electrical signal. For example, the image sensor module 700 may include an image sensor 710 and a printed circuit board 720 connected to the image sensor 710, and may further include an infrared filter. The infrared filter blocks light in the infrared region among the light incident through the lens barrel 210. The image sensor 710 converts light incident through the lens barrel 210 into an electrical signal. For example, the image sensor 710 may include a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS). The electrical signal converted by the image sensor 710 is output as an image through the display unit of the portable electronic device. The image sensor 710 is fixed to the printed circuit board 720 and is 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 housing 120 has a shape in which the top and the bottom thereof are open, and the lens barrel 210 and the actuator are accommodated in the inner space of the housing 120. The image sensor module 700 is disposed under the housing 120.

The case 110 is coupled to the housing 120 to surround the outer surface of the housing 120, and may protect the internal components of the camera module 100. In addition, the case 110 may shield electromagnetic waves. For example, the case 110 may shield the electromagnetic waves so that the electromagnetic waves generated from the camera module do not affect other electronic components in the portable electronic device.

As described above, the actuator includes a focus adjuster 400 for adjusting focus and a shake corrector 500 for correcting shake.

The focus adjusting unit 400 may include a magnet 410 and a driving coil 430 which generate a driving force to move the lens barrel 210 and the carrier 300 accommodating the lens barrel 210 in an optical axis (Z-axis) direction. Include.

The magnet 410 is mounted to the carrier 300. For example, the magnet 410 may be mounted on one surface of the carrier 300. The driving coil 430 may be mounted on the housing 120 and disposed to face the magnet 410. For example, the driving coil 430 may be disposed on one surface of the substrate 600, and the substrate 600 may be mounted on 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 changed. When a driving signal is applied to the driving coil 430, the carrier 300 may be moved in the optical axis (Z-axis) direction by the electromagnetic influence between the magnet 410 and the driving coil 430.

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

When the carrier 300 is moved, the rolling member B1 is disposed between the carrier 300 and the housing 120 to reduce friction between the carrier 300 and the housing 120. The rolling member B1 may have a ball shape. The rolling member B1 is disposed on both sides of the magnet 410.

The yoke 450 is disposed in the housing 120. For example, the yoke 450 is mounted to the substrate 600 and disposed in the housing 120. The yoke 450 is provided 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. The attractive force acts between the yoke 450 and the magnet 410 in a direction perpendicular to the optical axis (Z axis). Therefore, the rolling member B1 may be in contact with the carrier 300 and the housing 120 by the attraction force between the yoke 450 and the magnet 410. In addition, the yoke 450 may focus the magnetic force of the magnet 410 to prevent the leakage magnetic flux from occurring. For example, the yoke 450 and the magnet 410 form a magnetic circuit.

The present invention uses a closed loop control scheme that detects and feeds back the position of the lens barrel 210 during the focus adjustment process. Thus, a position calculator is provided for the closed loop control. The position calculator may detect the position of the lens barrel 210.

The shake correction unit 500 is used to correct the blurring of the image or the shaking of the video due to factors such as the shaking of the user during image shooting or video shooting. For example, the shake correction unit 500 compensates the shake by applying a relative displacement corresponding to the shake to the lens barrel 210 when a shake occurs during image capturing by a user's hand shake or the like. As an example, the shake correction unit 500 corrects the shake by moving the lens barrel 210 in a direction perpendicular to the optical axis (Z axis).

The shake correction unit 500 includes a plurality of magnets 510a and 520a and a plurality of driving coils 510b and 520b for generating a driving force to move the guide member in a direction perpendicular to the optical axis (Z axis). The frame 310 and the lens holder 320 may be inserted into the carrier 300 and disposed in the optical axis (Z-axis) direction to guide the movement of the lens barrel 210. The frame 310 and the lens holder 320 have a space in which the lens barrel 210 can be inserted. The lens barrel 210 is inserted into and fixed to the lens holder 320.

The frame 310 and the lens holder 320 are directions perpendicular to the optical axis (Z axis) with respect to the carrier 300 by the driving force generated by the plurality of magnets 510a and 520a and the plurality of driving coils 510b and 520b. Is moved to. Among the plurality of magnets 510a and 520a and the plurality of driving coils 510b and 520b, some of the magnets 510a and some of the driving coils 510b may have a first axis (X axis) perpendicular to the optical axis (Z axis). Direction, and the remaining magnets 520a and the remaining drive coils 520b generate the driving force in the direction of the second axis (Y axis) perpendicular to the first axis (X axis). Here, the second axis (Y axis) means an axis perpendicular to both the optical axis (Z axis) and the first axis (X axis). The plurality of magnets 510a and 520a are arranged to be perpendicular to each other in a plane perpendicular to the optical axis (Z axis).

The plurality of magnets 510a and 520a may be mounted on the lens holder 320, and the plurality of driving coils 510b and 520b facing the plurality of magnets 510a and 520a may be disposed on the substrate 600 to provide a housing 120. ) Is mounted.

The plurality of magnets 510a and 520a may move together with the lens holder 320 in a direction perpendicular to the optical axis (Z axis), and the plurality of driving coils 510b and 520b may be fixed to the housing 120. However, according to an exemplary embodiment, positions of the plurality of magnets 510a and 520a and the plurality of driving coils 510b and 520b may be changed.

The present invention uses a closed loop control scheme that detects and feeds back the position of the lens barrel 210 in the shake correction process. Thus, a position calculator for closed loop control is provided. The position calculator may detect the position of the lens barrel 210.

On the other hand, the camera module 100 includes a plurality of ball members for supporting the shake correction unit 500. The plurality of ball members serve to guide the movement of the frame 310, the lens holder 320, and the lens barrel 210 in the shake correction process. In addition, it also functions to maintain a gap between the carrier 300, the frame 310 and the lens holder 320.

The plurality of ball members include 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 (X-axis) direction, and the second ball member B3 is the lens holder. The movement of the 320 and the lens barrel 210 in the second axis (Y-axis) direction is guided.

For example, when the driving force in the first axis (X-axis) direction occurs, the first ball member B2 rolls in the first axis (X-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 (X-axis) direction. In addition, when the driving force in the second axis (Y axis) direction occurs, the second ball member B3 rolls in the second axis (Y 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 (Y-axis) direction.

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

First guide grooves 301 for receiving the first ball member B2 are formed on surfaces where the carrier 300 and the frame 310 face each other in the optical axis (Z-axis) direction. The first guide groove 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 fitted between the carrier 300 and the frame 310. In the state where the first ball member B2 is accommodated in the first guide groove 301, movement in the optical axis (Z axis) and the second axis (Y axis) directions is limited, and the first ball member B2 is in the first axis (X axis) direction. Only can be moved. For example, the first ball member B2 may be rolled only in the direction of the first axis (X axis). To this end, the planar shape of each of the plurality of guide grooves of the first guide groove 301 may be a rectangle having a length in the first axis (X-axis) direction.

Second guide grooves 311 accommodating the second ball member B3 are formed on surfaces where the frame 310 and the lens holder 320 face each other in the optical axis (Z-axis) direction. The second guide groove 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 fitted 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 311, movement in the optical axis (Z axis) and the first axis (X axis) direction is limited, and in the second axis (Y axis) direction. Only can be moved. For example, the second ball member B3 may be rolled only in the direction of the second axis (Y axis). To this end, 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 (Y-axis) direction.

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

As an example, when the driving force in the first axis (X-axis) direction occurs, the third ball member B4 rolls in the first axis (X-axis) direction. Accordingly, the third ball member B4 guides the movement of the lens holder 320 in the first axis (X axis) direction. In addition, the third ball member B4 rolls in the second axis (Y-axis) direction when a driving force in the second axis (Y-axis) direction occurs. Accordingly, the third ball member B4 guides the movement of the lens holder 320 in the second axis (Y axis) direction. On the other hand, the second ball member B3 and the third ball member B4 support and support the lens holder 320.

Third guide grooves 302 for receiving the third ball member B4 are formed on surfaces of the carrier 300 and the lens holder 320 facing each other in the optical axis (Z-axis) direction. The third ball member B4 is accommodated in the third guide groove 302 and fitted 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 302, movement in the optical axis (Z axis) direction is limited, and in the first axis (X axis) and the second axis (Y axis) directions. Can cloud movement. To this end, the planar shape of the third guide groove 302 may be circular. Accordingly, the third guide groove 302, the first guide groove 301, and the second guide groove 311 may have different planar shapes.

The first ball member B2 is capable of rolling movement in the first axis (X axis) direction, the second ball member B3 is capable of rolling movement in the second axis (Y axis) direction, and the third ball member B4. ) Is capable of rolling movement in the directions of the first axis (X axis) and the second axis (Y axis). Therefore, the plurality of ball members supporting the shake correction unit 500 of the present invention are different in degrees of freedom. Here, the degrees of freedom may refer to the number of independent variables required to represent the motion state of an object in a 3D coordinate system. In general, the degree of freedom of an object in a three-dimensional coordinate system is six. The motion of the object may be represented by a rectangular coordinate system in three directions and a rotational coordinate system in three directions. For example, in a three-dimensional coordinate system, the object may translate in translation along each axis (X, Y, Z), and may rotate in relation to each axis (X, Y, Z).

In the present specification, the degree of freedom means that the first ball member when the shake correction unit 500 is moved by the driving force generated in a direction perpendicular to the optical axis (Z axis) by applying power to the shake correction unit 500. The number of independent variables required to represent the movement of (B2), the second ball member B3, and the third ball member B4. For example, the third ball member B4 is rolling along two axes (first axis (X axis) and second axis (Y axis)) by a driving force generated in a direction perpendicular to the optical axis (Z axis). The first ball member B2 and the second ball member B3 are capable of rolling movement along one axis (first axis (X axis) or second axis (Y axis)). Therefore, the freedom degree of the 3rd ball member B4 is larger than the freedom degree of the 1st ball member B2 and the 2nd ball member B3.

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

In addition, when a driving force is generated in the second axis (Y axis) direction, the lens holder 320 and the lens barrel 210 move in the second axis (Y axis) direction. Here, the 2nd ball member B3 and the 3rd ball member B4 make rolling motion along a 2nd axis (Y-axis). At this time, the movement of the first ball member B2 is limited.

On the other hand, the present invention is provided with a plurality of yokes (510c, 520c) to maintain the contact state between the shake correction unit 500 and the first to third ball members (B2, B3, B4). The plurality of yokes 510c and 520c are fixed to the carrier 300 and disposed to face the plurality of magnets 510a and 520a in the optical axis (Z-axis) direction. Therefore, an attraction force is generated between the plurality of yokes 510c and 520c and the plurality of magnets 510a and 520a in the optical axis (Z-axis) direction. Since the shake correction unit 500 is pressed toward the plurality of yokes 510c and 520c by the attraction force between the plurality of yokes 510c and 520c and the plurality of magnets 510a and 520a, the shake correction unit 500 The frame 310 and the lens holder 320 may maintain contact with the third to third ball members B2, B3, and B4. The plurality of yokes 510c and 520c are materials capable of generating an attraction force with the plurality of magnets 510a and 520a. For example, the plurality of yokes 510c and 520c may be provided as magnetic materials.

According to the present invention, the frame 310 and the lens holder 320 provide a plurality of yokes 510c and 520c so that the frame 310 and the lens holder 320 can be in contact with the first to third ball members B2, B3 and B4. The stopper 330 is provided to prevent the first to third ball members B2, B3, and B4, the frame 310, and the lens holder 320 from being separated out of the carrier 300. The stopper 330 is coupled to the carrier 300 to cover at least a portion of the upper surface of the lens holder 320.

3 is a block diagram 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 one of the focus adjuster 400 and the shake correction unit 500 of FIG. 2.

When the actuator 1000 of FIG. 3 corresponds to the focus adjusting unit 400 of FIG. 2, the lens barrel may be moved in the optical axis direction to perform an auto focusing function of the camera module. Therefore, when the actuator 1000 of FIG. 3 performs the autofocus function, the driving device 1100 may apply a driving signal to the driving coil 1200 to provide a driving force to the lens barrel in the optical axis direction.

When the actuator 1000 of FIG. 3 corresponds to the shake correction unit 500 of FIG. 2, the lens barrel is moved in a direction perpendicular to the optical axis to perform an optical image stabilization (OIS) function of the camera module. You can. Therefore, when the actuator 1000 of FIG. 3 performs the optical shake correction function, the driving device 1100 may apply a driving signal to the driving coil 1200 to provide driving force to the lens barrel in a direction perpendicular to the optical axis. Can be.

The actuator 1000 according to the exemplary embodiment of the present invention may include a driving device 1100, a driving coil 1200, a detected unit 1300, and a position calculator 1400.

The driving device 1100 generates the driving signal Sdr according to the input signal Sin applied from the outside and the feedback signal Sf generated from the position calculator 1400, and drives the generated driving signal Sdr. The coil 1200 may be provided.

When the driving signal Sdr provided from the driving device 1100 is applied to the driving coil 1200, the lens barrel is in an optical axis direction or a direction perpendicular to the optical axis due to electromagnetic interaction between the driving coil 1200 and the magnet. Can move in the vertical direction. For example, the driving signal Sdr may be provided to the driving coil 1200 in the form of at least one of a current and a voltage.

The position calculator 1400 may calculate the position of the detected unit 1300 according to the frequency of the oscillation signal Sosc obtained from the driving coil. The position calculator 1400 may calculate the displacement of the lens barrel through the position calculation of the detected unit 1300.

The frequency of the oscillation signal Sosc obtained from the driving coil 1200 may vary according to the position of the detected unit 1300.

The to-be-detected part 1300 is composed of one of a magnetic material and a conductor, and is located within a magnetic field range of the driving coil 1200. For example, the detected part 1300 may be disposed to face the driving coil 1200. The detected part 1300 may be provided at one side of the lens barrel to move in the same direction as the moving direction of the lens barrel. According to an embodiment, the detection unit 1400 may be provided in at least one of a plurality of frames and a carrier coupled to the lens barrel, in addition to the lens barrel.

In the present embodiment, the to-be-detected unit 1300 may correspond to the magnets 410, 510a and 520a of FIG. 2 disposed to face the driving coil 1200, and according to an embodiment, to implement the to-be-detected unit 1300. A separate device may be provided.

When the to-be-detected part 1300 composed of a magnetic body and one of the conductors moves together with the lens barrel, the inductance of the driving coil 1200 is changed. That is, the frequency of the oscillation signal Sosc may be changed according to the movement of the detected unit 1300.

The position calculator 1400 may calculate a position of the detected unit 1300, generate a feedback signal Sf, and provide the feedback signal Sf to the driving device 1100.

When the feedback signal Sf is provided to the driving device 1100, the driving device 1100 may generate the driving signal Sdr by comparing the input signal Sin with the feedback signal Sf. That is, the driving device 1100 may be driven in a close loop type comparing the input signal Sin with the feedback signal Sf. The driving device 1100 of the closed loop type is driven in a direction of reducing an error between a target position of the detected unit 1300 included in the input signal Sin and a current position of the magnet 1300 included in the feedback signal Sf. Can be. Compared to the open loop method, driving of the closed loop method has an advantage of improving linearity, accuracy, and repeatability.

4 is a view showing in detail the main part of the actuator of FIG.

Referring to FIG. 4, the driving device 1100 according to an embodiment of the present invention may include a control unit 1110 and a driving circuit unit 1120. The driving device of FIG. 4 may be implemented by a driver IC (driver integrated circuit).

The controller 1110 may generate a control signal S_gate from the input signal Sin and the feedback signal Sf provided from the position calculator 1400. In detail, the controller 1110 may generate the control signal S_gate by comparing the input signal Sin indicating the target position of the lens barrel with the feedback signal Sf indicating the current position of the lens barrel.

The driving circuit unit 1120 may generate the driving signal Sdr according to the control signal S_gate and provide the driving signal Sdr to the driving coil 1200. The driving signal Sdr may be provided at both ends of the driving coil 1200 in the form of at least one of a current and a voltage. The lens barrel may be moved to a target position by the driving signal Sdr generated by the driving circuit unit 1120 and provided to the driving coil 1200.

The driving circuit unit 1120 may include an H bridge circuit driving in both directions by the control signal S_gate to apply the driving signal Sdr to the driving coil 1200. The H bridge circuit may include a plurality of transistors connected to both ends of the driving coil 1200 in the form of an H bridge. When the driving circuit unit 1120 is driven by a voice coil motor method, the control signal S_gate provided from the controller 1120 may be applied to the gate of the transistor provided in the H bridge circuit.

5 is a view illustrating in detail a driving circuit part of the driving apparatus of FIG. 4.

Referring to FIG. 5, the driving circuit unit 1120 may include a plurality of transistors T1, T2, T3, and T4 connected to the driving coil 1200 in the form of an H bridge. In detail, the driving circuit unit 1120 may include a first path transistor unit 1121 and a second path transistor unit 1122. The first path current Idc (−) flows through the first path transistor unit 1121, and the second path current Idc (+) flows through the second path transistor unit 1122.

The first path transistor unit 1121 may include a first transistor T1 and a second transistor T2. The first transistor T1 may be disposed between the driving power supply Vcc and one end of the driving coil 1200, and the second transistor T2 may be disposed between the other end of the driving coil 1200 and the ground.

The first path transistor unit 1121 may form a first path of the driving signal Sdr applied to the driving coil 1200 according to the control signal S_gate provided from the controller 1110. For example, the control signal S_gate may be provided to the gates of the first transistor T1 and the second transistor T2. For example, when the control signal S_gate is at a high level, the first transistor T1 and the second transistor T2 are turned on and when the control signal S_gate is at a low level, the first transistor T1 is turned on. And the second transistor T2 may be turned off. Meanwhile, according to the embodiment, different control signals are provided to the first transistor T1 and the second transistor T2 so that both the first transistor T1 and the second transistor T2 are turned on. One of the first transistor T1 and the second transistor T2 may be controlled to adjust the amount of current flowing in the first path.

The second path transistor unit 1122 may include a third transistor T3 and a fourth transistor T4. The third transistor T3 may be disposed between the driving power supply Vcc and the other end of the driving coil 1200, and the fourth transistor T4 may be disposed between one end of the driving coil 1200 and the ground.

The second path transistor unit 1122 may form a second path of the driving signal Sdr applied to the driving coil 1200 according to the control signal S_gate provided from the controller 1110. For example, the control signal S_gate may be provided to the gates of the third transistor T3 and the fourth transistor T4. For example, when the control signal S_gate is at a high level, the third transistor T3 and the fourth transistor T4 are turned on, and when the control signal S_gate is at a low level, the third transistor T3 is turned on. And the fourth transistor T4 may be turned off. According to an exemplary embodiment, different control signals are provided to the third transistor T3 and the fourth transistor T4 so that both the third transistor T3 and the fourth transistor T4 are turned on, One of the third transistor T3 and the fourth transistor T4 may be controlled to adjust the amount of current flowing in the second path.

The first path transistor unit 1121 and the second path transistor unit 1122 may form different paths of the driving signal Sdr applied to the driving coil 1200. For example, the operation period of the first path transistor unit 1121 is the same as the non-operation period of the second path transistor unit 1122, and the non-operation period of the first path transistor unit 1121 is the second path transistor unit ( 1122 may be the same as the operation section.

Here, the operation section is a section in which the transistors of the first path transistor section 1121 and the second path transistor section 1122 turn on, and the non-operation section is a first path transistor section 1121 and a second path transistor section. It may be understood that the transistors of 1122 are turned off.

That is, the first path transistor unit 1121 and the second path transistor unit 1122 may be selectively operated by the control signal S_gate provided from the controller 1110. In an operation period of the first path transistor unit 1121, the first transistor T1 and the second transistor T2 of the first path transistor unit 1121 are turned on, and the second path transistor unit 1122 is turned on. In the non-operation period, the third transistor T3 and the fourth transistor T4 of the second path transistor unit 1122 may be turned off. In the non-operation period of the first path transistor unit 1121, the first transistor T1 and the second transistor T2 of the first path transistor unit 1121 are turned off, and the second path transistor unit ( In an operation period of 1122, the third transistor T3 and the fourth transistor T4 of the second path transistor unit 1122 may be turned on.

6 is a circuit diagram of a driving circuit unit and a position calculator according to an embodiment of the present invention. In FIG. 6, the driving coil 1200 is illustrated as an equivalent circuit by a first inductor L1, a second inductor L2, a first resistor R1, and a second resistor R2 connected in series. Here, the first resistor R1 and the second resistor R2 may correspond to the equivalent resistance component of the driving coil 1200 or the parasitic resistance component of the branch where the driving coil 1200 is disposed.

Referring to FIG. 6, the position calculator 1400 may include a first capacitor Cgnd disposed in parallel with the driving coil 1200, and a tap terminal of the driving coil 1200. A second capacitor Ct disposed between grounds and a position calculating circuit 1410 connected to a node between the tab terminal of the driving coil 1200 and the second capacitor Ct may be included. Here, the tap terminal of the driving coil 1200 may mean a point of the winding constituting the driving coil 1200.

7 shows an equivalent circuit of the circuit of FIG. 6 for a direct current signal. Here, the equivalent circuit of the circuit of FIG. 6 with respect to the DC signal is a gate control signal for driving the transistors of the driving circuit unit, and may be understood as the equivalent circuit of FIG. 6 when a DC signal is provided.

The high level direct current signal is provided to the first transistor T1 and the second transistor T2 as the gate control signal, and the low level direct current signal is used as the gate control signal and the third transistor T3 and the fourth transistor ( When the first path current Idc (−) flows, the first transistor T1 is turned on and the first path current according to the voltage provided to the gate of the second transistor T2. The current amount of (Idc (−)) can be determined. In addition, a low level direct current signal is provided to the first transistor T1 and the second transistor T2 as a gate control signal, and a high level direct current signal is used as the gate control signal and the third transistor T3 and the fourth transistor. When the second path current Idc (+) flows in the transistor T4, the third transistor T3 is turned on, and according to the voltage provided to the gate of the fourth transistor T4, the second transistor T2 is turned on. The current amount of the path current Idc (+) may be determined.

On the other hand, with respect to the DC signal, the first capacitor Cgnd and the second capacitor Ct of the position calculator are equivalent to an open circuit, so that the components of the position calculator affect the operation of the driving circuit unit 1120. It may not be crazy.

8-11 show an equivalent circuit of the circuit of FIG. 6 for an alternating signal. Here, the AC signal may be understood as an oscillation signal output from an oscillation circuit to be described later. Therefore, the equivalent circuit of the circuit of FIG. 6 for the AC signal can be understood as the equivalent circuit of FIG. 6 for the oscillation signal.

In order to explain an equivalent circuit of the circuit of FIG. 6 with respect to an AC signal, assuming that the first transistor T1 and the second transistor T2 are turned off, the circuit of FIG. 6 may be equivalent to that of FIG. 8. have. In FIG. 8, the third transistor T3 is turned on, and the amount of current of the second path current Idc (+) is determined according to the voltage provided to the gate of the fourth transistor T4 to determine the second path current. (Idc (+)) may flow in the driving coil 1200.

At this time, in the turn-on operation of the third transistor T3, since the equivalent resistance of the third transistor T3 is very small, the third transistor T3 is equivalent to a short circuit, and thus the third transistor T3. Both terminals of ND are grounded for AC signal. That is, both terminals of the third transistor T3 may function as a ground AC GND for the AC signal.

On the other hand, the fourth transistor T4 is equivalent to an open circuit when the second path current Idc (+) is close to zero. On the other hand, when the second path current Idc (+) is close to the maximum value, it is equivalent to a short circuit, and both terminals of the fourth transistor T4 maintain the ground state with respect to the AC signal.

The first capacitor Cgnd connected in parallel to both ends of the driving coil 1200 is equivalent to a short circuit with respect to an AC signal. Therefore, the first capacitor Cgnd may provide the ground AC GND for the AC signal to both ends of the driving coil 1200 by the AC signal. Therefore, the circuit of FIG. 8 may be equivalent, like the circuit of FIG. 9, regardless of the amount of current of the second path current Idc (+). In FIG. 8, although the first capacitor Cgnd is connected to both ends of the driving coil 1200 in parallel, two first capacitors Cgnd are provided and two first capacitors Cgnd are provided. One may be configured to be connected between one end of the drive coil 1200 and the ground, the other is connected between the other end and the ground of the drive coil 1200.

Meanwhile, the first inductor L1 and the second inductor L2 of the driving coil 1200 connected in parallel with respect to the tap terminal of the driving coil 1200 may be the inductor L (= (L1 * L2) / (L1). Equivalent to + L2)).

The capacitor Ct may be expressed according to Equation 1 below. Referring to Equation 1, the capacitor Ct may be expressed as a capacitor C1 seen from the first inductor L1 side, a capacitor C2 seen from the second inductor L2 side, and a parasitic capacitor CP. Can be.

In addition, based on the tap terminal of the driving coil 1200, the first resistor R1 and the second resistor R2 connected in parallel may be equivalent to the resistor Rp according to Equation 2 below.

Thus, the circuit of FIG. 9 may be equivalent to the circuit of FIG. 10. At this time, the oscillation frequency of the oscillation circuit composed of the capacitor Ct, the resistor Rp, and the inductor L is expressed by Equation 3 below. Hereinafter, for convenience of description, the capacitor Ct, the resistor Rp, and the inductor L connected in parallel will be referred to as an oscillation circuit.

11 is a block diagram illustrating in detail a position calculating circuit according to an exemplary embodiment of the present invention.

The position calculation circuit 1410 may include an oscillation maintaining unit 1410a, a frequency sensing unit 1410b, and a determination unit 1410c.

The oscillation holding unit 1410a may include an amplifier Amp, a capacitor Cf, and a capacitor Cc. One end of the capacitor Cc is connected to the output terminal of the amplifier Amp, and the capacitor Cf is connected between the other end of the capacitor Cc and the output terminal of the amplifier Amp.

The oscillation holding unit 1410a compensates for oscillation energy loss due to the resistor Rp in order to maintain oscillation by the inductor L and the capacitor Ct of the oscillation circuit, specifically, LC oscillation. At this time, the transconductance gain gm of the amplifier Amp for maintaining oscillation satisfies Equation 4 below.

In the state where oscillation is maintained, when the distance between the detection unit 1300 and the inductor L changes as the lens barrel moves, the inductance of the inductor L is changed to change the frequency of the oscillation signal output from the oscillation circuit. do. At this time, oscillation of the oscillation circuit may occur at the tap terminal of the driving coil 1200 even when a current flows in either direction of the first path current Idc (−) and the second path current Idc (+). have.

Accordingly, the position calculator 1400 may calculate the position of the lens barrel according to the frequency change of the oscillation signal according to the change in inductance of the driving coil in any section where a control signal is applied to the plurality of transistors of the driving circuit 1120. Can be.

The oscillation signal output from the oscillation circuit is input to the amplifier Amp through the capacitor Cf, and the amplifier Amp amplifies the input oscillation signal and outputs it through the capacitor Cc to maintain oscillation of the oscillation circuit. have. The amplified oscillation signal may be input to the frequency sensing unit 1410b, and the frequency sensing unit 1410b may acquire frequency information of the oscillation signal.

12 is a block diagram of a frequency sensing unit according to an embodiment of the present invention.

Referring to FIG. 12, the frequency sensing unit 1410b according to the present exemplary embodiment may include a comparator 1410b_1, an end gate 1410b_2, and a latch 1410b_3.

The comparator 1410b_1 converts the oscillation signal into a pulse signal and provides it to the AND gate 1410b_2. As an example, the comparator 1410b_1 may be implemented as a Schmitter circuit. The AND gate 1410b_2 logically multiplies the pulse signal input from the comparator 1410b_1 and the reference period signal Sref to provide a logical product signal to the latch 1410b_3. For example, the reference period signal Sref may have a period of 1 [S]. The latch 1410b_3 may obtain frequency information by counting a logical product signal input from the AND gate 1410b_2.

Meanwhile, in another embodiment, the frequency sensing unit 1410b may calculate the frequency of the oscillation signal by counting the oscillation signal using the reference clock CLK. The reference clock CLK is a clock signal having an extremely high frequency, and for example, when the oscillation signal Sosc of one cycle is counted as the reference clock CLK during the reference period, the reference corresponds to the oscillation signal of one cycle. The count value of the clock CLK may be calculated. The frequency sensing unit 1410b may calculate the frequency of the oscillation signal by using the count value of the reference clock CLK and the frequency of the reference clock CLK.

Referring back to FIG. 11, the determination unit 1410c may receive the frequency of the oscillation signal from the frequency sensing unit 1410b and determine the position of the detected unit 1300 according to the frequency of the oscillation signal. The determination unit may include a memory, and the location information of the detected part corresponding to the frequency of the oscillation signal may be stored in the memory. The memory may be implemented as a nonvolatile memory including one of a flash memory, an electrically erasable programmable read-only memory (EEPROM), and a ferroelectric RAM (FeRAM). Therefore, when the frequency of the oscillation signal is transmitted, the determination unit may determine the position of the detected unit 1300 by referring to the position information of the detected unit 1300 previously stored in the memory.

The actuator of the camera module according to an embodiment of the present invention can accurately detect the position of the magnet from the change in inductance of the driving coil. Furthermore, since a separate hall sensor is not employed, manufacturing cost of the actuator of the camera module can be reduced and space efficiency can be improved.

Although the present invention has been described by specific embodiments such as specific components and the like, but the embodiments and the drawings are provided to assist in a more general understanding of the present invention, the present invention is not limited to the above embodiments. For those skilled in the art, various modifications and variations can be made from these descriptions.

Accordingly, the spirit of the present invention should not be limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the appended claims, fall within the scope of the spirit of the present invention. I will say.

110: case
120: housing
210: lens barrel
300: carrier
310: frame
320: lens holder
600: substrate
700: image sensor module
1000: Actuator
1100: drive unit
1110: control unit
1120: driving circuit section
1200: drive coil
1300: detected part
1400: position calculation unit
1410: position output circuit
1410a: Oscillation Keeper
1410b: frequency sensing unit
1410c: Judgment

Claims (16)

Lens barrels;
A drive coil disposed to be opposite to the to-be-detected part provided at one side of the lens barrel;
A driving device for providing a driving signal to the driving coil; And
Calculating a position of the lens barrel from a first capacitor providing a ground for an AC signal to the driving coil, a second capacitor connected to the driving coil to form an oscillating circuit, and a frequency of the oscillating circuit A position calculator including a position calculator; Camera module comprising a.
The method of claim 1,
And the first capacitor is connected in parallel with the driving coil.
The method of claim 1,
Two first capacitors are provided, one of the two first capacitors is connected between one end of the driving coil and ground, and the other is connected between the other end of the driving coil and ground.
The method of claim 1,
And the second capacitor is disposed between the tab terminal of the driving coil and the ground.
The circuit of claim 1, wherein the position calculating circuit comprises:
A camera module including an oscillation holding unit for maintaining the oscillation of the oscillation circuit.
The method of claim 5,
The oscillation circuit is a camera module is connected to the resistance component, inductor component, and capacitor component in parallel.
The method of claim 6,
And a resistance component of the oscillation circuit corresponds to at least one of an equivalent resistance component of the drive coil and a parasitic resistance component of a branch in which the drive coil is disposed.
The method of claim 7, wherein the oscillation holding unit,
And an amplifier for amplifying the oscillation signal of the oscillation circuit.
The method of claim 8,
The transconductance gain of the amplifier satisfies the following equation.
[Equation]

(gm: transconductance gain, Rp: resistance component of the oscillator circuit)
Lens barrels;
A drive coil disposed to be opposite to the to-be-detected part provided at one side of the lens barrel;
A driving device including a driving circuit unit including a plurality of transistors connected to the driving coil, and a control unit providing a control signal to a gate of each of the plurality of transistors; And
A first capacitor connected in parallel with the driving coil, and a second capacitor disposed between a tap terminal of the driving coil and a ground, wherein the lens is changed according to a change in inductance of the driving coil according to the movement of the detected part. A position calculator for calculating a position of the barrel; Camera module comprising a.
The method of claim 10,
And the first capacitor provides a ground for an alternating current signal to the drive coil.
The method of claim 10,
And the second capacitor forms the driving coil and the oscillation circuit.
The method of claim 12, wherein the position calculation unit,
And a camera module for detecting a change in inductance of the driving coil according to the frequency of the oscillation circuit.
The method of claim 12, wherein the position calculation unit,
And amplifying the oscillation signal of the oscillation circuit to maintain oscillation of the oscillation circuit.
The method of claim 10,
And the plurality of transistors are connected to both ends of the driving coil in the form of an H bridge circuit.
The method of claim 10, wherein the position calculation unit,
And a camera module configured to calculate a position of the lens barrel according to a change in inductance of the driving coil in a section where the control signal is applied to the gate of each of the plurality of transistors.

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