KR101605125B1 - Driving assembly for image stabilization of digital camera - Google Patents

Abstract

The present invention relates to an image stabilization device. The camera shake correcting device is an image shake correcting device for correcting shake of a camera. The camera shake correcting device includes: a correcting lens driven on a two-dimensional plane composed of first and second axes independent from each other; First hall sensors for detecting a lens position in a first axial direction, and a second hall sensor disposed in at least one of the correction lens and for detecting a lens position in a second axial direction.

According to the present invention, a camera-shake correction apparatus is provided in which errors in position detection caused by rotation of a correction lens are eliminated and control accuracy of a correction operation is improved.

Description

[0001] The present invention relates to an image stabilization device,

The present invention relates to an image stabilization device, and more particularly, to an image stabilization device that corrects a shake of an image due to a shaking of a photographer.

In general, a camera captures an image of an object to form an image data, and records the image in a proper file format. If the camera shake or vibration due to peripheral vibration is reflected in the captured image as it is, the image quality deteriorates .

In recent years, various image stabilization techniques have been developed to automatically correct camera shake. For example, a method of fixing the imaging position on the image sensor by driving and controlling the optical lens by an appropriate amount of movement corresponding to the camera shake can be considered. For example, the correction operation can be realized by calculating the target position of the optical lens from the camera shake and performing the feed-back control using the difference signal with the current position of the optical lens. At this time, a hole sensor is used for detecting the position of the optical lens. The detection error of the hall sensor directly affects the control performance of the correction operation, leading to deterioration of the control performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image stabilization device that eliminates errors in position detection caused by rotation of a correction lens and improves control accuracy of a correction operation.

In order to achieve the above object and other objects,

An apparatus for correcting camera shake, comprising:

A correction lens driven on a two-dimensional plane consisting of a first axis and a second axis independent of each other;

First hall sensors arranged in pairs on both sides of the correction lens and for detecting a lens position in a first axial direction; And

And a second hall sensor disposed on at least one of the correction lenses and for detecting a lens position in a second axial direction.

The camera-shake correction device includes:

A pair of first magnets arranged to face the pair of first Hall sensors and for providing a driving force in a first axial direction;

A second magnet disposed opposite the second Hall sensor and for providing a driving force in a second axial direction; And

And a driving coil disposed to face the first and second magnets and performing electromagnetic interaction with the first and second magnets.

Preferably, the pair of first magnets produces a rotational moment in a direction that is offset relative to the lens center.

Preferably, the second magnet is disposed on a second axis passing through the lens center.

The camera-shake correction device includes:

A lens support plate mounted on the correction lens and movable on a two-dimensional plane consisting of a first axis and a second axis;

A base for movably supporting the lens supporting plate; And

And a cover mounted on the base through the lens support plate and including a pair of the first hall sensors and a second hall sensor mounted thereon.

For example, a pair of first magnets for providing a driving force in a first axial direction is disposed on a lens supporting plate facing the pair of first hall sensors,

And a second magnet for providing a driving force in a second axial direction is disposed on a lens supporting plate facing the second hall sensor.

For example, the different position signals output from the first hall sensors may be calculated as converted values through predetermined arithmetic processing, and the converted values may be referred to as positional information of the lenses.

For example, the different position signals output from the first hall sensors are calculated as conversion values through predetermined arithmetic processing, and both the position signal before conversion and the conversion value after conversion can be referred to as position information of the lens .

According to the camera-shake correction apparatus of the present invention, by arranging the hall sensors on both sides of the correction lens, the error of the position detection caused by the rotation of the correction lens can be substantially eliminated. That is, when a rotational displacement occurs in the correction lens, the hall sensor does not reflect the actual position of the correction lens, and detects an erroneous position. According to the proposed correction apparatus, since the correction operation is controlled based on the output of the hall sensor disposed on both sides of the lens, the control accuracy of the correction operation can be improved.

Hereinafter, an image stabilization device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is an exploded perspective view of an image stabilization device according to an embodiment of the present invention, and Fig. 2 is a vertical sectional view of the correction device shown in Fig. The camera shake correction apparatus 100 includes a correction lens 120, a lens support plate 130 on which the correction lens 120 is mounted, and a base 150 on which the lens support plate 130 is supported.

The magnets 131a, 131b, 132a and 132b are assembled on both sides of the lens supporting plate 130 and the driving coil 155 is vertically mounted on the base 150 so as to face the magnets 131a, 131b, 132a and 132b. And the yoke 160 are assembled. For example, the driving coil 155 and the yoke 160 may be assembled to the upper surface and the lower surface of the base 150 so as to face the magnets 131a, 131b, 132a, and 132b, respectively.

The magnets 131a, 131b, 132a and 132b and the drive coil 155 are assembled at positions facing each other and perform electromagnetic interaction to constitute a VCM (Voice Coil Motor) actuator, for example. Both ends of the driving coil 155 can be connected to a circuit board (not shown) for applying a controlled signal. The lens support plate 130 is driven on first and second axis planes (XY planes) perpendicular to the optical axis (Z axis) in accordance with electromagnetic interaction between the magnets 131a, 131b, 132a and 132b and the drive coil 155 And the correction operation is performed.

The magnets 131a, 131b, 132a, and 132b and the yoke 160 are assembled to face each other and exert magnetic attracting force with respect to each other. The lens support plate 130 and the base 150 are brought into close contact with each other by using the attraction force between the magnets 131a, 131b, 132a and 132b and the yoke 160. When the driving power is shut off, the magnets 131a and 131b , 132a and 132b are aligned with the center of the yoke 160, thereby returning the lens support plate 130 to a predetermined position. Meanwhile, the lens support plate 130 and the base 150 are disposed to face each other with the ball bearing 140 (FIG. 2) interposed therebetween. The base 150 supports the first and second axial planes (X-Y planes) of the lens support plate 130 through the ball bearings 140.

The cover 110 may be disposed at the upper end of the correction device 100. The cover 110 is assembled on the base 150 with the lens support plate 130 interposed therebetween. Hall sensors 111a, 111a and 112 for detecting the position of the correction lens 120 are assembled to the cover 110. [ The Hall sensors 111a, 111b and 112 are assembled at positions facing the magnets 131a, 131b, 132a and 132b, and detect the magnetic fields of the magnets 131a, 131b, 132a and 132b, , 132a, and 132b of the correction lens 120, which are integrally moving.

The correction lens 120 tracks movement of the imaging position of the subject while moving on the first and second axis planes (XY planes) to correct shaking of the image caused by camera shake, fixes the imaging position of the subject The correction is performed. For example, assuming that the target position of the correction lens 120 for canceling the shaking motion and the current position of the correction lens 120 detected by the hall sensors 111a, 111b, and 112 are input, the magnets 131a, 131b, and 132a And 132b and the VCM actuator knitted by the driving coil 155, thereby bringing the correcting lens 120 close to the target position.

3 is a view for explaining the arrangement structure of the magnets 131a, 131b, 132a and 132b. Referring to FIG. 1, a correction lens 120 is fitted in a central position of a lens support plate 130, and pairs of first magnets 131a and 131b and second magnets 132a, 132b. The first magnets 131a and 131b provide the first axial driving force FYa and FYb and are aligned such that the N-S polarity is reversed along the first axis (Y axis) direction. The second magnets 132a and 132b provide driving forces FXa and FXb in the second axial direction and are aligned such that the N-S polarity is inverted along the second axis (X axis) direction. The first and second magnets 131a, 131b, 132a and 132b together with the drive coils 155 disposed opposite to each other are provided with first and second axial driving forces FYa, FYb, FXa and FXb . Here, the independent control means that the position of the correction lens 120 on the two-dimensional plane (XY plane) of the first and second axes is controlled so that the driving forces FYa and FYb in the first axis direction are parallel to the first axis Only the displacement of the second axis (X axis) is generated without affecting the position of the second axis (X axis), and conversely the driving forces FXa and FXb in the second axis direction are generated only in the direction of the second axis , But does not affect the position in the first axis (Y axis) direction. The first axis (Y axis) and the second axis (X axis) are preferably composed of two different axes of the vertical coordinate system.

The driving forces FYa and FYb in the first axial direction generated by the first magnets 131a and 131b act in directions parallel to each other and have points of action opposite to each other with respect to the correcting lens 120. [ Therefore, the driving forces FYa and FYb in the first axial direction appear in the form of a resultant force that cooperates with each other in the translational direction, and in the direction of canceling the rotational moment of the counterpart in the rotational direction. For example, one driving force FYa generates a rotation moment in one rotation direction with respect to the lens center C by using La as a rotary arm, and the driving force FYb of the other component generates Lb C in the opposite direction of rotation. At this time, by disposing the first magnets 131a and 131b at symmetrical positions with respect to the lens center C (La = Lb), the rotational moments caused by the driving forces FYa and FYb in the first axial direction are canceled out And the net rotation component acting on the correction lens 120 can be removed. On the other hand, the second magnets 132a and 132b are disposed on a second axis (X axis) passing through the lens center C. Therefore, the driving forces FXa and FXb in the second axial direction generated by the second magnets 132a and 132b do not have a rotary arm with respect to the lens center C, and do not generate a rotation moment.

Fig. 4 is a view for explaining an arrangement structure of the hall sensors 111a, 111b and 112. Fig. Hall sensors 111a, 111b, and 112 for detecting the position of the correction lens 120 are disposed at positions facing the magnets 131a, 131b, and 132b. The hall sensors 111a, 111b and 112 detect the position of the correcting lens 120 in the short axis direction and include first hall sensors 111a and 111b for detecting a position in the first axis direction (Y axis) And a second hall sensor 112 for detecting a position in the second axis (X axis) direction. The first Hall sensors 111a and 111b are arranged to face the first magnets 131a and 131b whose NS polarity is inverted in the first axis direction (X axis), and the magnetic fields of the first magnets 131a and 131b And detects the displacement in the first axis (Y axis) direction by detecting the change. The second hall sensor 112 is disposed to face the second magnet 132b whose NS polarity is inverted in the second axis direction (X axis), and detects a magnetic field change of the second magnet 132b, (X-axis) direction.

The first hall sensors 111a and 111b are arranged in pairs so as to face the first magnets 131a and 131b on both sides of the correction lens 120 and the second hall sensor 112 is disposed on the other side of the correction lens 120 And is disposed so as to face the disposed second magnet 132b. The structure in which the first hall sensors 111a and 111b are arranged in a pair has a structure in which the correction lens 120 is moved to the correct target position despite the rotational displacement of the correction lens 120 due to the driving forces FYa and FYb in the first axis direction Close. Hereinafter, this will be described in detail.

When it is desired to send the correction lens 120 from the current position (Y = Y0) to the target position (Y = Y1) according to the result of calculating the target position of the correction lens 120 for canceling the camera shake, If the movement of the correcting lens 120 has only the translation component in the direction of the first axis (Y axis) and does not have the rotational component as shown in Figs. 5A and 5B, the position of the magnets 131a and 131b The positions of the lens 120 are aligned with each other and the correction lens 120 can be controlled based on the outputs of the first hall sensors 111a and 111b sensing the magnets 131a and 131b. That is, based on the output signals of the first hall sensors 111a and 111b, the driving forces FYa and FYb in the first axial direction are maintained until the correction lens 120 reaches the target position (Y = Y1) The lens 120 can be brought close to the target position (Y = Y1).

However, the driving forces FYa and FYb in the first axial direction can cause a rotation moment in the correction lens 120, and if the movement of the correction lens 120 has a rotational component as shown in Fig. 6A , The positions (Y = Y1, Y = -Y1) of the magnets 131a and 131b and the position (Y = Y0) of the correction lens 120 do not coincide with each other. At this time, one of the pair of first hall sensors 111a and 111b detects that the correction lens 120 has reached the target position (Y = Y1), and the other hall sensor 111a detect that the correction lens 120 is still below the target position (Y = Y1). In response to this, as shown in FIG. 6B, for one piece of the correction lens 120 that has reached the target position (Y = Y1), the driving force is cut off, while for the other piece that is below the target position (Y = Y1) By maintaining the driving force, the correcting lens 120 can be brought close to the correct target position. 7A and 7B, even when the movement of the correcting lens 120 has a rotational component in the opposite direction, the first Hall sensors 111a and 111b arranged on both sides of the correcting lens 120, The correction lens 120 can be brought close to the correct target position by interrupting the driving force for one of the parts that have reached the target position (Y = Y1) in the target position (Y = Y1) have. The first hall sensors 111a and 111b are disposed on both sides of the correction lens 120 and the first Hall sensors 111a and 111b are disposed on both sides of the correction lens 120. Therefore, The correcting lens 120 can be approached to the correct target position based on each output signal of the correction lens 120. [

As shown in FIGS. 8 and 9, if the first Hall sensors 111a 'and 111b' are independently disposed on either side of the correction lens 120, the first Hall sensors 111a 'and 111b' The correction lens 120 will be controlled depending on the erroneous position detection. That is, according to the rotation state of the correction lens 120, the driving to the correction lens 120 is stopped before the target position (Y = Y1) is reached, or the correction lens 120 is moved to the target position (Y = Y1 ), The driving position is shifted to the target position. For example, as shown in FIGS. 8 and 9, although the correction lens 120 is still below the target position (Y = Y1), the error output of the first Hall sensors 111a 'and 111b' It can be determined that the target position (Y = Y1) has been reached and the driving forces FYa and FYb in the first axial direction can be blocked.

FIG. 10 is a diagram for explaining parallel signal processing applied to the output signals of the first hall sensors 111a and 111b. In the parallel signal processing, appropriate calculation processing (summing, differential, and average) is applied to the position signals Y1 and Y2 output from the first hall sensors 111a and 111b, and a new calculation value (Y3). Then, the main processor grasps the current position of the correction lens 120 from the stored calculation value Y3, and generates a proper driving signal for bringing the correction lens 120 close to the target position.

11 is a diagram for explaining serial signal processing applied to the output signals of the first hall sensors 111a and 111b. In the serial signal processing, the position signals Y1 and Y2 output from the first hall sensors 111a and 111b are stored, and the new signals Y1 and Y2 calculated by applying appropriate arithmetic processing to the position signals Y1 and Y2 And stores the calculated value (Y3) together. The main processor then grasps the current positional state of the correction lens 120 from the stored position signals Y1 and Y2 and the calculated value Y3 and outputs an appropriate drive signal for approximating the correction lens 120 to the target position Respectively. In the serial signal processing, since the position signals (Y1, Y2) output from the first hall sensors (111a, 111b) and the calculated value (Y3) converted into the calculation result are stored together, more detailed position information can be obtained It is possible to generate a drive signal with high reliability.

The camera shake correcting apparatus 100 according to the present invention can be disposed in a barrel structure of a camera and includes a barrel type barrel structure in which the barrel assembly is drawn in and out of the barrel assembly in accordance with the on / It is of course possible to apply the present invention to a bending-type barrel structure having an optical system arranged vertically to the bending-type barrel structure. Particularly, the proposed camera shake correction apparatus 100 has a problem that it is difficult to configure the correction apparatus 100 for spatial constraint, more specifically, for slimming down the thickness direction, It can be suitably applied to a bending-type barrel structure in which it is difficult to provide a rotation restricting element.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is an exploded perspective view of an image stabilization device according to a preferred embodiment of the present invention.

2 is a vertical sectional view of the shaking motion correcting apparatus shown in Fig.

FIG. 3 is a view showing a magnet arrangement structure applied to the shake correction apparatus of FIG. 1. FIG.

4 is a view showing an arrangement structure of a hall sensor applied to the shake correction apparatus of FIG.

5A and 5B are diagrams showing a correcting operation of a correcting lens approaching a target position based on a position signal of a hall sensor when motion of the correcting lens has a translational component.

6A and 6B are diagrams showing a correcting operation of a correcting lens approaching a target position based on a position signal of a hall sensor when the motion of the correcting lens has a rotational component in one direction.

FIGS. 7A and 7B are diagrams showing a correcting operation of a correcting lens approaching a target position based on a position signal of a hall sensor when the motion of the correcting lens has a rotational component in the opposite direction. FIG.

Figs. 8 and 9 are views showing an example in which an erroneous correcting operation occurs when the movement of the correcting lens has a rotational component in a different direction in a structure in which the hole sensor is disposed only on one side of the lens. Fig.

FIG. 10 is a diagram for explaining parallel signal processing applied to the output signals of the first Hall sensors. FIG.

11 is a diagram for explaining serial signal processing applied to the output signals of the first hall sensors.

Description of the Related Art

100: Anti-shake device 110: Cover

111a, 111b: first hall sensor 112: second hall sensor

115: Hall sensor 120; Correction lens

130: lens supporting plate 131a, 131b: first magnet

132a, 132b: second magnet 140: ball bearing

150: base 155: drive coil

160: yoke C: lens center

La: Rotating arm (distance) from the center of the lens to the first magnet

Lb: rotating arm (distance) from the center of the lens to the second magnet

FYa, FYb: driving force in the first axial direction

FX, FXa, FXb: driving force in the second axial direction

Claims (8)

An apparatus for correcting camera shake, comprising: A correction lens driven on a two-dimensional plane consisting of a first axis and a second axis independent of each other; First hall sensors arranged in pairs on both sides of the correction lens and for detecting a lens position in a first axial direction; A second hall sensor disposed on at least one of said correction lenses and for detecting a lens position in a second axial direction; A pair of first magnets arranged to face the pair of first Hall sensors and for providing a driving force in a first axial direction; A second magnet disposed opposite the second Hall sensor and for providing a driving force in a second axial direction; And And a drive coil disposed to face the first and second magnets to perform electromagnetic interaction, Wherein the pair of first magnets generate a rotational moment in a direction canceling each other with respect to the center of the lens and the second magnet is disposed on a second axis passing through the center of the lens. delete delete delete The method according to claim 1, A lens support plate mounted on the correction lens and movable on a two-dimensional plane consisting of a first axis and a second axis; A base for movably supporting the lens supporting plate; And And a cover mounted on the base through the lens support plate, the cover including a pair of the first hall sensors and a second hall sensor. 6. The method of claim 5, A pair of first magnets for providing a driving force in a first axial direction is disposed on a lens supporting plate facing the pair of first hall sensors, And a second magnet for providing a driving force in a second axial direction is disposed on a lens supporting plate facing the second hall sensor. The method according to claim 1, Wherein the different position signals output from the first hall sensors are subjected to predetermined arithmetic processing to be calculated as converted values, and the converted values are referred to as position information of the lens. The method according to claim 1, Wherein the position signals before the conversion and the converted values after the conversion are both referred to as the position information of the lens, Device.

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