IC CHIP, CAMERA MODULE, AND POSITION CONTROL SYSTEM

Provided is an IC chip comprising: a plurality of magnetic sensors which detect magnetic fields according to positions of the movable body in the first direction and the second direction; a first position information setting unit which calculates a first relative position of the movable body with respect to a first drive range in the first direction in accordance with the magnetic fields detected by the plurality of magnetic sensors; a second position information setting unit which calculates a second relative position of the movable body with respect to a second drive range in the second direction in accordance with the magnetic fields detected by the plurality of magnetic sensors, a first target position adjustment unit which calculates a first target position in the first drive range; and a second target position adjustment unit which calculates a second target position in the second drive range.

The contents of the following patent application(s) are incorporated herein by reference:NO. 2022-191147 filed in JP on Nov. 30, 2022

BACKGROUND

1. Technical Field

The present invention relates to an IC chip, a camera module, and a position control system.

2. Related Art

An actuator, a lens drive apparatus, a lens control apparatus, a camera module, and a position detection apparatus are known which detect positions of a movable body on a plurality of axes (see Patent Documents 1, 2, and 3).

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: International Publication No. 2021/065679Patent Document 2: Japanese Patent Application Publication No. 2019-120747Patent Document 3: Japanese Patent No. 6695898Patent Document 4: Japanese Patent Application Publication No. 2021-051277Patent Document 5: Japanese Patent Application Publication No. 2012-103497Patent Document 6: Japanese Patent Application Publication No. 2007-114121

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to claims. In addition, not all combinations of features described in the embodiments are essential to solutions of the invention. In addition, description of the same components may be omitted by assigning them the same reference numerals.

In the present specification, one side in a direction parallel to an optical axis of a lens may be referred to as “upper” and the other side is referred to as “lower”. “Upper” and “lower” directions are not limited to a direction parallel to the gravitational direction.

In the present specification, a case where a size or an amount is described as “same” or “equal” may include a case where there is an error due to a variation in manufacturing or the like. The error is, for example, within 5%. In addition, a case where an angle is described as “parallel”, “perpendicular”, or “orthogonal” may include a case where there is an error due to a variation in manufacturing or the like. The error is, for example, within 5 degrees.

FIG.1Ais a perspective view showing an example of a camera module100according to a first embodiment of the present invention. The camera module100is provided in a camera or a portable apparatus with a camera function. The camera module100includes a movable body10including an optical element20. The optical element20is a lens or an image capturing unit such as a CMOS image sensor. The movable body10adjusts a relative position between the lens and the image capturing unit by moving one of the lens and the image capturing unit with respect to the other. In each embodiment, an example will be described in which the movable body10includes a lens and moves the lens, but the movable body10may include an image capturing unit and move the image capturing unit. In a case where the movable body10moves the image capturing unit, the camera module100has a function and a configuration similar to those for the case where the movable body10moves the lens. In the present specification, an axis parallel to an optical axis of the optical element20(the lens in the present example) is referred to as a Z axis, and two axes orthogonal to the Z axis are referred to as an X axis and a Y axis. The X axis and the Y axis are orthogonal to each other. In the present specification, the optical axis of the optical element20may be simply referred to as the optical axis. The image capturing unit such as the CMOS image sensor which receives light having passed through the lens is provided below the lens (on a negative direction side on the Z axis), but illustration thereof is omitted inFIG.1A. The optical axis of the lens is an axis which connects a focal position and a central point on an XY plane of the lens. A normal to an upper surface of the lens at the central point on the XY plane of the lens may be defined as the optical axis. In addition, also in a case where the image capturing unit is provided as the optical element20, the optical axis of the lens may be treated as the optical axis of the optical element20. In another example, a normal to an image capturing surface of the image capturing unit at a center of the image capturing surface may be defined as the optical axis of the optical element20.

The movable body10has a plurality of surfaces12. As an example, a surface12is a surface parallel to the optical axis of the optical element20, but the surface12may have an angle with respect to the optical axis. In the example shown inFIG.1A, the movable body10is a cuboid or a cube, and has four surfaces12including a first surface12-1to a fourth surface12-4which are side surfaces parallel to the optical axis. In another example, the movable body10may have three surfaces12, or may have five or more surfaces12. Each surface12in the example shown inFIG.1Ais perpendicular to either the Y axis or the X axis. In the example shown inFIG.1A, the first surface12-1and a second surface12-2are parallel to a YZ plane, and a third surface12-3and the fourth surface12-4are parallel to a XZ plane. Each surface12is planar, but may include a curved portion or a concavo-convex portion.

The movable body10is provided to be able to move in at least two directions. The movable body10may be able to move in the direction parallel to the optical axis. Moving the movable body10in the direction parallel to the optical axis can, for example, control the focal position of the optical element20. In addition, the movable body10may be able to move in a direction intersecting the optical axis. Intersecting refers to not being parallel. The movable body10may be able to move in one or more directions orthogonal to the optical axis. Moving the movable body10in a direction different from that of the optical axis can offset a vibration of an apparatus provided with the camera module100, to capture an image with less blur. The movable body10in the present example is able to move in directions of at least two of the X axis, the Y axis, or the Z axis. The movable body10may be provided with one of the lens and the image capturing unit, and may not be provided with the other. As a result, movement of the movable body10relatively moves one of the lens and the image capturing unit with respect to the other.

The camera module100includes one or more IC chips70which will be described later. Each IC chip70controls any one of or a plurality of drive units30. A drive unit30generates a drive force for moving the movable body10. The drive unit30may move the movable body10by a magnetic force, may move the movable body10by using a piezoelectric element, may move the movable body10through expansion and contraction using a shape memory alloy (SMA), or may move the movable body10by another method. In the present example, at least one drive unit30moves the movable body10by the magnetic force. All the drive units30may move the movable body10by the magnetic force.

The camera module100in the present example includes an IC chip70-1and an IC chip70-2. The IC chip70-1in the present example controls the drive unit30to move the movable body10along two axes. The IC chip70-1in the present example controls a first drive unit30-1and a second drive unit30-2to move the movable body10along the Z axis and the X axis.

The IC chip70-2in the present example controls the drive unit30to move the movable body10along one axis. The IC chip70-2in the present example controls a third drive unit30-3to move the movable body10along the Y axis.

The first drive unit30-1has a portion arranged on the first surface12-1of the movable body10, and generates a first drive force for driving the movable body10in a first direction. The first drive force may be the magnetic force. The second drive unit30-2has a portion arranged on the second surface12-2of the movable body10different from the first surface12-1, and generates a second drive force for driving the movable body10in a second direction intersecting the first direction. The third drive unit30-3has a portion arranged on the third surface12-3of the movable body10, and generates a third drive force for moving the movable body10in a third direction. The first direction may be a direction perpendicular to the first surface12-1, may be the direction parallel to the optical axis, or may be another direction. The second direction may be a direction perpendicular to the second surface12-2, may be the direction parallel to the optical axis, or may be another direction. The third direction may be a direction perpendicular to the third surface12-3, may be the direction parallel to the optical axis, or may be another direction. In the example shown inFIG.1A, the first drive unit30-1moves the movable body10in the first direction parallel to the optical axis. In addition, the second drive unit30-2moves the movable body10in the second direction perpendicular to the second surface12-2. In addition, the third drive unit30-3moves the movable body10in the third direction perpendicular to the third surface12-3. The first direction, the second direction, and the third direction intersect one another. The first direction, the second direction, and the third direction may be any one of an X axis direction, a Y axis direction, and a Z axis direction. In the example shown inFIG.1A, the first direction is the Z axis direction, the second direction is the X axis direction, and the third direction is the Y axis direction.

The first drive unit30-1in the present example has a first magnet32-1and a first magnetic field generation unit34-1. One of the first magnet32-1and the first magnetic field generation unit34-1is provided on the first surface12-1of the movable body10, and the other of the first magnet32-1and the first magnetic field generation unit34-1is provided at a position facing the first surface12-1. The camera module100has a fixed portion including a surface facing one or more surfaces12of the movable body10, but illustration thereof is omitted inFIG.1A. The movable body10may have the first magnet32-1. In the example shown inFIG.1A, the movable body10is provided with the first magnet32-1, and the fixed portion is provided with the first magnetic field generation unit34-1. In another example, the fixed portion may be provided with the first magnet32-1, and the movable body10may be provided with the first magnetic field generation unit34-1. The same arrangement of the magnetic field generation unit34and the magnet32applies to the other drive units30.

Each magnetic field generation unit34has, for example, a coil. Each coil winds in a surface parallel to the surface12. That is, the magnetic field generation unit34generates a magnetic field perpendicular to the magnet32. Inverting a direction of a current flowing through the coil can invert a direction of the magnetic field generated by the magnetic field generation unit34.

The magnet32has a portion with a first polarity or a second polarity on a surface facing the magnetic field generation unit34. The first polarity is one of a south pole and a north pole, and the second polarity is the other of the south pole and the north pole. In each drawing, the portion with the second polarity in the magnet32is hatched, and the portion with the first polarity is not hatched.

When the magnetic field generation unit34generates the magnetic field, an attraction force or a repulsive force is generated between the magnetic field generation unit34and a portion with a predetermined polarity in the magnet32in accordance with the direction of the magnetic field generated by the magnetic field generation unit34. Since the magnet32is fixed to the movable body10, the movable body10moves in either direction in accordance with the attraction force or the repulsive force generated in the magnet32.

The first magnet32-1has a first portion41with the first polarity and a second portion42with the second polarity. The first magnet32-1has the first portion41and the second portion42on a surface facing the first magnetic field generation unit34-1. The first portion41and the second portion42may be arranged side by side in the first direction or the second direction. The first portion41and the second portion42in the present example are arranged side by side in the Z axis direction. The first portion41has the first polarity, and the second portion42has the second polarity. The first magnet32-1may have the portion with the second polarity behind the first portion41, and have the portion with the first polarity behind the second portion42. The expression “behind the portion in the magnet32” refers to a surface, among surfaces of each portion, on a side opposite to the surface facing the magnetic field generation unit34.

The first magnetic field generation unit34-1in the present example is a first coil arranged facing the first portion41and the second portion42so as to straddle both the first portion41and the second portion42. The first coil may have a central axis of a winding wire arranged so as to overlap a boundary line between the first portion41and the second portion42, or may have the central axis arranged so as to deviate from the boundary line. The first magnetic field generation unit34-1generates a magnetic field in a direction perpendicular to the first magnet32-1. The movable body10moves in the first direction in accordance with the direction of the magnetic field generated by the first magnetic field generation unit34-1. In the example shown inFIG.1A, the first direction is a direction parallel to the Z axis. For example, if the magnetic field generated by the first magnetic field generation unit34-1is directed to attract the first portion41, the movable body10moves in a direction (a negative direction of the Z axis in the example shown inFIG.1A) in which a center of the first portion41of the first magnet32-1in the Z axis direction approaches a center of the first magnetic field generation unit34-1in the Z axis direction. If the magnetic field generated by the first magnetic field generation unit34-1is directed to attract the second portion42, the movable body10moves in a direction (a positive direction of the Z axis in the example shown inFIG.1A) in which a center of the second portion42of the first magnet32-1in the Z axis direction approaches the center of the first magnetic field generation unit34-1in the Z axis direction. A distance by which the movable body10is moved can be controlled by a strength of the magnetic field generated by the magnetic field generation unit34(an amount of the current flowing through the coil in the present example).

Part of the second drive unit30-2is provided on the second surface12-2of the movable body10. The second surface12-2in the present example is a surface facing the first surface12-1. The second surface12-2may be parallel to the first surface12-1. The movable body10may have a second magnet32-2. The second drive unit30-2in the present example has the second magnet32-2provided on the second surface12-2of the movable body10and a second magnetic field generation unit34-2.

The second magnet32-2has a first portion on a surface facing the second magnetic field generation unit34-2. The second magnet32-2may have a second portion behind the first portion. In this case, the first portion has the first polarity or the second polarity, and the second portion has a polarity opposite to that of the first portion.

The second magnetic field generation unit34-2is arranged facing the first portion of the second magnet32-2. The second magnetic field generation unit34-2generates a magnetic field perpendicular to the second magnet32-2. In accordance with a direction of the magnetic field generated by the second magnetic field generation unit34-2, an attraction force or a repulsive force is generated between the second magnet32-2and the second magnetic field generation unit34-2, and the movable body10moves in the second direction. In the example shown inFIG.1A, the second direction is a direction parallel to the X axis.

Part of the third drive unit30-3is provided on the third surface12-3of the movable body10. The third surface12-3in the present example is a surface intersecting the second surface12-2. The third surface12-3may be orthogonal to the second surface12-2. The third drive unit30-3in the present example has a third magnet32-3provided on the third surface12-3of the movable body10and a third magnetic field generation unit34-3.

The third magnet32-3has a first portion61on a surface facing the third magnetic field generation unit34-3. The third magnet32-3may have a second portion behind the first portion61. In this case, the first portion61has the first polarity or the second polarity, and the second portion has a polarity opposite to that of the first portion61.

The third magnetic field generation unit34-3is arranged facing the first portion61of the third magnet32-3. The third magnetic field generation unit34-3generates a magnetic field perpendicular to the third magnet32-3. In accordance with a direction of the magnetic field generated by the third magnetic field generation unit34-3, an attraction force or a repulsive force is generated between the third magnet32-3and the third magnetic field generation unit34-3, and the movable body10moves in the third direction. In the example shown inFIG.1A, the third direction is a direction parallel to the Y axis.

The IC chip70-1is provided at a position facing the first magnet32-1. If the first magnet32-1is provided in the movable body10, the IC chip70-1is provided in the fixed portion. If the first magnet32-1is provided in the fixed portion, the IC chip70-1is provided in the movable body10.

The IC chip70-1detects a position in the first direction and a position in the second direction of the movable body10. The IC chip70-1may have a plurality of magnetic sensors72. The magnetic sensor72may be any magnetic sensor as long as it can detect a direction and a strength of a magnetic field. The plurality of magnetic sensors72of the IC chip70-1detect magnetic fields according to positions of the movable body10in the first direction and the second direction. The first direction and the second direction may be two directions among a direction parallel to, a direction perpendicular to, or a rotational direction around, an optical axis of light entering the optical element20. The IC chip70-1may have at least one of a processing circuit which processes a result of detection by the magnetic sensor72or a driver for driving the drive unit30. The IC chip70-1may be formed on a silicon substrate, or may be formed on a semiconductor substrate made of another material. The magnetic sensor72may be a TMR element using a tunnel magnetoresistive effect, may be a GMR element using a giant magnetoresistive effect, may be a Hall element using a Hall effect, or may be another type of sensor. The magnetic sensor72may be formed of a compound semiconductor, or may be formed of another material. The IC chip70-1in the present example detects magnetic fields from the first magnet32-1, and detects a position of the movable body10based on the detected magnetic fields.

The IC chip70-2is provided at a position facing the third magnet32-3. If the third magnet32-3is provided in the movable body10, the IC chip70-2is provided in the fixed portion. If the third magnet32-3is provided in the fixed portion, the IC chip70-2is provided in the movable body10.

The IC chip70-2detects a position of the movable body10in the third direction. The IC chip70-2may have one or more magnetic sensors72. The IC chip70-2may have a configuration similar to that of the IC chip70-1.

FIG.1Bis a top view showing an example of the camera module100according to the first embodiment of the present invention.FIG.1Billustrates a fixed portion14, the illustration of which is omitted inFIG.1A. The fixed portion14has a surface16facing the movable body10in a direction intersecting the optical axis of the optical element20. The fixed portion14in the present example has a first surface16-1facing the first surface12-1of the movable body10, a second surface16-2facing the second surface12-2of the movable body10, a third surface16-3facing the third surface12-3of the movable body10, a fourth surface16-4facing the fourth surface12-4of the movable body10. In the present example, the first magnetic field generation unit34-1and the IC chip70-1are provided on the first surface16-1, the second magnetic field generation unit34-2is provided on the second surface16-2, and the third magnetic field generation unit34-3and the IC chip70-2are provided on the third surface16-3. The camera module100may have a position detection unit71which is arranged at the surface16of the fixed portion14facing the first surface12-1of the movable body10or at the first surface12-1of the movable body10and which detects the position in the first direction and the position in the second direction of the movable body10. The position detection unit71may refer to the IC chip70-1, or may include the IC chip70-1. The position detection unit71has a function of compensating for an error in the position of the movable body10in the first direction associated with a motion in the second direction of the movable body10which will be described later.

FIG.2shows an exemplary arrangement of the first magnet32-1, the IC chip70-1, and the magnetic sensor72in a YZ plane. The IC chip70-1in the present example has a first magnetic sensor72-1and a second magnetic sensor72-2. The first magnet32-1in the present example has the first portion41and the second portion42arranged side by side in the Z axis direction (a first direction) on a surface facing the IC chip70-1. In the present specification, the surface facing the IC chip70-1in the first magnet32-1may be referred to as an arrangement surface. The first portion41and the second portion42may have the same position and length in the Y axis direction. The first portion41and the second portion42may have the same length in the Z axis direction.

The plurality of magnetic sensors72include the first magnetic sensor72-1arranged facing the first portion41and the second magnetic sensor72-2arranged facing the second portion42. At least two of the plurality of magnetic sensors72may be arranged along a direction other than the first direction and a second direction. The first magnetic sensor72-1and the second magnetic sensor72-2may be arranged side by side in the first direction (the Z axis direction). The first magnetic sensor72-1and the second magnetic sensor72-2may have the same position and length in the Y axis direction. The first magnetic sensor72-1and the second magnetic sensor72-2may have the same length in the Z axis direction. The first magnetic sensor72-1and the second magnetic sensor72-2may be arranged at positions symmetrical to each other with respect to a boundary line between the first portion41and the second portion42. Magnetic field strengths detected by the first magnetic sensor72-1and the second magnetic sensor72-2change depending on a position of the movable body10in the first direction (the Z axis direction), and also change depending on a position of the movable body10in the second direction (the X axis direction).

The first magnet32-1may be used for driving in an optical axis direction. As a result, the first magnet32-1has a longer drive range than the second magnet32-2used for driving in a direction perpendicular to the optical axis direction, it may have a larger planar size than the second magnet32-2. In addition, since movement in the optical axis direction is easily affected by the gravitational direction, the first magnet32-1may have a larger thickness than the second magnet32-2in order to improve the drive force.

If a position of each member is defined in the present specification, unless otherwise described, the position of each member is defined with the movable body10present at a predetermined origin position. An origin position in the Z axis direction is a center of a movable range of the movable body10in the Z axis direction. Origin positions in the X axis direction and the Y axis direction are positions of the movable body10for the time when a center (or an optical axis) of the optical element20overlaps a center of a light receiving surface in an image capturing unit below the optical element20.

The magnetic sensor72of the IC chip70-2and the third magnet32-3may have configurations similar to or different from those of the magnetic sensor72of the IC chip70-1and the first magnet32-1. The third magnet32-3in the present example may have a surface with a single polarity on a surface facing the IC chip70-2. The IC chip70-2may have one or more magnetic sensors72facing the third magnet32-3.

FIG.3shows relationships between a position of a movable body10in the Z axis direction and strengths of magnetic fields detected by the first magnetic sensor72-1and the second magnetic sensor72-2. In each diagram, the origin position of the movable body10described above is referred to as an origin0. The first magnetic sensor72-1detects a first magnetic field strength, and the second magnetic sensor72-2detects a second magnetic field strength. The first magnetic field strength of the magnetic field detected by the first magnetic sensor72-1is referred to as B1, and the second magnetic field strength of the magnetic field detected by the second magnetic sensor72-2is referred to as B2. In an initial state shown inFIG.2, the first magnetic sensor72-1detects a large amount of magnetic field from the first portion41, and detects the magnetic field strength B1which is positive. The second magnetic sensor72-2detects a large amount of magnetic field from the second portion42, and detects the magnetic field strength B2which is negative.

The movable body10moving in the Z axis direction changes a ratio of the magnetic field from the first portion41and the magnetic field from the second portion42which are detected by each magnetic sensor72. For example, if the movable body10moves to a positive side of the Z axis from the state shown inFIG.2, a distance between the first magnetic sensor72-1and the second portion42decreases, so that a magnetic field component from the first portion41included in the magnetic field detected by the first magnetic sensor72-1decreases, and a magnetic field component from the second portion42increases. Therefore, as shown inFIG.3, when the movable body10moves in a positive direction of the Z axis, the first magnetic field strength B1detected by the first magnetic sensor72-1linearly decreases. Similarly, when the movable body10moves in the positive direction of the Z axis, the second magnetic field strength B2detected by the second magnetic sensor72-2linearly decreases. In addition, if the movable body10moves to a negative side of the Z axis, the distance between the first magnetic sensor72-1and the second portion42increases, so that the magnetic field component from the first portion41included in the magnetic field detected by the first magnetic sensor72-1increases, and the magnetic field component from the second portion42decreases. Therefore, as shown inFIG.3, when the movable body10moves in a negative direction of the Z axis, the first magnetic field strength B1detected by the first magnetic sensor72-1linearly increases. Similarly, when the movable body10moves in the negative direction of the Z axis, the second magnetic field strength B2detected by the second magnetic sensor72-2linearly increases.

FIG.4shows relationships between a position of the movable body10in the X axis direction and strengths of magnetic fields detected by the first magnetic sensor72-1and the second magnetic sensor72-2. In the initial state shown inFIG.2, the first magnetic sensor72-1detects the first magnetic field strength B1which is positive. The second magnetic sensor72-2detects the second magnetic field strength B2which is negative.

When the movable body10moves in the X axis direction, a distance between each magnetic sensor72and the first magnet32-1changes. InFIG.4, a direction in which the distance between the magnetic sensor72and the first magnet32-1decreases is referred to as a positive direction of the X axis, and a direction in which the distance increases is referred to as a negative direction of the X axis. An absolute value of the magnetic field strength detected by each magnetic sensor72attenuates in proportion to the square to the cube of the distance from the first magnet32-1. A magnetosensitive axis of each magnetic sensor72is set to exhibit characteristics shown inFIG.3andFIG.4.

The IC chip70-1detects a position of the movable body10in a first direction and a position of the movable body10in a second direction based on the first magnetic field strength B1detected by the first magnetic sensor72-1and the second magnetic field strength B2detected by the second magnetic sensor72-2. The IC chip70-1may calculate the position of the movable body10in the second direction based on at least one of the first magnetic field strength B1or the second magnetic field strength B2. The IC chip70-1may calculate the position of the movable body10in the first direction based on one of a sum of the first magnetic field strength B1and the second magnetic field strength B2and a difference between the first magnetic field strength B1and the second magnetic field strength B2, and calculate the position of the movable body10in the second direction based on the other of the sum and the difference.

As shown inFIG.3, B2+B1decreases as the movable body10moves in a positive direction of the Z axis, and B2+B1increases as the movable body10moves in a negative direction of the Z axis. The IC chip70-1may calculate a position of the movable body10in the Z axis direction based on the sum of the first magnetic field strength B1and the second magnetic field strength B2. The IC chip70-1may calculate the position of the movable body10in the Z axis direction based on a value (B2+B1)/(B2−B1) obtained by dividing the sum of the first magnetic field strength B1and the second magnetic field strength B2by the difference between the first magnetic field strength B1and the second magnetic field strength B2.

As shown inFIG.4, an absolute value of B2−B1increases as the movable body10moves in the positive direction of the X axis, the absolute value of B2−B1decreases as the movable body10moves in the negative direction of the X axis. The IC chip70-1may calculate the position of the movable body10in the X axis direction based on the difference between the first magnetic field strength B1and the second magnetic field strength B2.

According to the present example, it is possible for one IC chip70-1to detect positions of the movable body10in two directions. Therefore, it is possible to reduce the number of parts of the camera module100or to reduce a size of the camera module100, as compared to a case where the IC chip70is provided in each direction. In addition, the first magnet32-1included in the first drive unit30-1is also used as a magnet for position detection. Therefore, there is no need to separately provide the magnet for position detection, and it is possible to reduce the number of parts of the camera module100or to reduce the size of the camera module100.

The magnetic sensor72of the IC chip70-2detects a magnetic field strength similar to B1or B2inFIG.4. In this case, a magnet position represented by the horizontal axis inFIG.4refers to a position of the movable body10in the Y axis direction. The IC chip70-2may calculate the position of the movable body10in the Y axis direction based on a result of detection by the magnetic sensor72. In another example, the camera module100may have only the magnetic sensor72without having the IC chip70-2on the third surface16-3. The IC chip70-1may calculate the position of the movable body10in the Y axis direction based on the result of detection by the magnetic sensor72on the third surface16-3.

FIG.5illustrates an influence of a position of the movable body10in the X axis direction on a result of calculating a position of the movable body10in the Z axis direction. The horizontal axis inFIG.5represents the position in the Z axis direction, and the vertical axis represents a value of a magnetic field after the arithmetic operation shown inFIG.3orFIG.4is performed in an arithmetic operation unit. InFIG.5, the position of the movable body10in the Z axis direction is calculated based on a value (B2+B1)/(B2−B1) obtained by dividing the sum of the first magnetic field strength B1and the second magnetic field strength B2inFIG.3by the difference between the first magnetic field strength B1and the second magnetic field strength B2. A drive range in the figure represents a range in which the IC chip70moves the movable body10. In the present specification, a range in which the movable body10is able to mechanically move may be referred to as a movable range. Even if a strength of a magnetic field generated by the magnetic field generation unit34is increased, the movable body10cannot move beyond a certain range due to a mechanical interference or the like. The certain range is referred to as the movable range. On the other hand, the drive range is a movement range of the movable body10previously set in the IC chip70or the like. The IC chip70controls the magnetic field generated by the magnetic field generation unit34such that the movable body10moves within the drive range. The IC chip70may detect the position of the movable body10or control the position of the movable body10by using a position code assigned to each position within the drive range. For example, a minimum value of the position code is assigned to one end portion position of the drive range, and a maximum value of the position code is assigned to the other end portion position of the drive range. The drive range may be a range narrower than the movable range. Calculating the position of the movable body10in the Z axis direction may mean collating previously obtained data shown inFIG.5with an arithmetically operated magnetic field calculated by the IC chip70-1and calculating a relative position of the movable body10with respect to the drive range. A solid line in the figure indicates a case where the position of the movable body10in the X axis direction is at an origin, and a dotted line in the figure indicates a case where the position of the movable body10in the X axis direction is at +300 μm.

FIG.6illustrates an influence of a position of the movable body10in the Z axis direction on a result of calculating a position of the movable body10in the X axis direction. The horizontal axis inFIG.6represents the position in the X axis direction, and the vertical axis represents a value of a magnetic field after the arithmetic operation shown inFIG.3orFIG.4is performed in an arithmetic operation unit. InFIG.6, the position of the movable body10in the X axis direction is calculated based on the difference between the first magnetic field strength B1and the second magnetic field strength B2inFIG.4. A solid line in the figure indicates a case where the position of the movable body10in the Z axis direction is at an origin, and a dotted line in the figure indicates a case where the position of the movable body10in the Z axis direction is at +300 μm.

As shown inFIG.5andFIG.6, when the IC chip70-1calculates the position of the movable body10in the X axis or Z axis direction, the calculation result is affected by the position of the movable body10on another axis.FIG.5shows an example in which an actual position of the movable body10in the X axis direction affects a detection position of the movable body10in the Z axis direction. Similarly, an actual position of the movable body10in the Y axis direction may affect the detection position of the movable body10in the Z axis direction. In addition,FIG.6shows an example in which an actual position of the movable body10in the Z axis direction affects a detection position of the movable body10in the X axis direction. Similarly, the actual position of the movable body10in the Y axis direction may affect the detection position of the movable body10in the X axis direction. In addition, the actual position of the movable body10in the X axis direction or the Z axis direction may affect a detection position of the movable body10in the Y axis direction. In this manner, the detection position of the movable body10on another axis varies depending on the actual position of the movable body10on each axis. Therefore, an error is generated in a result of detecting the position of the movable body10. In addition, it may be erroneously detected that the movable body10has moved to an end of a drive range even though it has not actually moved to the end of the drive range, which may restrict further movement of the movable body10. In this case, the movable body10no longer moves to the end of the drive range, and an actual drive range of the movable body10becomes narrow. In addition, it may be erroneously detected that the movable body10is still located within the drive range even though the movable body10has actually moved to the end of the movable range, which may result in an attempt to move the movable body10further. In this case, even if the attempt is made to move the movable body10, the movable body10no longer moves. Therefore, it is desirable that the IC chip70-1corrects a relative position based on the position of the movable body10on another axis.

FIG.7shows an exemplary configuration of the IC chip70-1. The IC chip70-1in the present example has the magnetic sensor72, an AMP22, an A/D unit24, a temperature sensor26, a first arithmetic operation unit36-1, a second arithmetic operation unit36-2, a first position information setting unit38-1, a second position information setting unit38-2, a target position reception unit44, a first target position obtainment unit46-1, a second target position obtainment unit46-2, a first target position adjustment unit48-1, a second target position adjustment unit48-2, a first control unit54-1, a second control unit54-2, a first D/A unit56-1, a second D/A unit56-2, a first driver58-1, and a second driver58-2. The magnetic sensor72outputs a signal according to a detected magnetic field strength to the AMP22. The AMP22amplifies the signal from the magnetic sensor72, to output it to the A/D unit24. The A/D unit24converts the signal amplified by the AMP22into a digital signal, and outputs it to the first arithmetic operation unit36-1and the second arithmetic operation unit36-2. A value of the digital signal indicates the detected magnetic field strength. The temperature sensor26detects temperature inside the IC chip70-1. In addition, the IC chip70-1may compensate for a temperature characteristic of an internal circuit by using an output of the temperature sensor26. The first arithmetic operation unit36-1and the second arithmetic operation unit36-2calculate a sum signal of or a difference signal between the first magnetic field strength B1and the second magnetic field strength B2, described inFIGS.3to6. The first arithmetic operation unit36-1may calculate a position of the movable body10in a first direction based on at least one of a sum of, a difference between, or the sum of/the difference between, the first magnetic field strength and the second magnetic field strength, and the second arithmetic operation unit36-2may calculate a position of the movable body10in a second direction based on at least one of the sum of or the difference between the first magnetic field strength and the second magnetic field strength. For example, the first arithmetic operation unit36-1calculates the sum signal of the first magnetic field strength B1and the second magnetic field strength B2, and the second arithmetic operation unit36-2calculates the difference signal between the first magnetic field strength B1and the second magnetic field strength B2.

The first position information setting unit38-1calculates a first relative position of the movable body10with respect to a first drive range in the first direction in accordance with magnetic fields detected by the plurality of magnetic sensors72. Similarly, the second position information setting unit38-2calculates a second relative position of the movable body10with respect to a second drive range in the second direction in accordance with the magnetic fields detected by the plurality of magnetic sensors72. The first position information setting unit38-1may previously set information on an end point of the first drive range in the first direction. Setting of end point information may be indicated by the position code described above. The first position information setting unit38-1may convert a result in the first arithmetic operation unit36-1into the position code, and calculate the first relative position of the movable body10with respect to the first drive range based on the end point information. The second position information setting unit38-2may previously set information at an end point of the second drive range in the second direction. Setting of end point information may be indicated by a position code in an IC. The second position information setting unit38-2may convert a result in the second arithmetic operation unit36-2into the position code in the IC, and calculate the second relative position of the movable body10with respect to the second drive range based on the end point information.

The first position information setting unit38-1and the second position information setting unit38-2may update the first drive range and the second drive range. The second position information setting unit38-2may update the end point information of the second drive range in the second direction in accordance with the result in the first arithmetic operation unit36-1. The first position information setting unit38-1may update the end point information of the first drive range in the first direction based on the second relative position calculated by using the end point information updated in the second position information setting unit38-2. The first position information setting unit38-1may sequentially calculate the first relative position based on the second relative position of the movable body10in the second direction. Sequentially calculating the first relative position may mean calculating the first relative position each time the second relative position is updated. The first position information setting unit38-1and the second position information setting unit38-2may correct an output result from the arithmetic operation unit36by setting and updating the end point information without directly correcting the output result from the arithmetic operation unit36. In the present specification, reference to correction may include calculation and updating. A specific method of correction will be described later.

The IC chip70-1has the target position reception unit44. The target position reception unit44receives a first target position in the first direction and a second target position in the second direction of the movable body10from an outside. Each target position may be set based on an operation by a user of the camera module100, or may be set based on an arithmetic operation result for realizing an auto-focusing function, an image stabilization function, or the like. The first target position obtainment unit46-1obtains the first target position from the target position reception unit44. The second target position obtainment unit46-2obtains the second target position from the target position reception unit44. The first target position adjustment unit48-1calculates the first target position in the first drive range. The second target position adjustment unit48-2calculates the second target position in the second drive range. The first position information setting unit38-1and the first target position adjustment unit48-1may correct at least one of the first relative position or the first target position based on at least one of the second relative position or the second target position. The first target position adjustment unit48-1may correct the first target position in the first drive range in accordance with the second target position corrected in the second target position adjustment unit48-2. The second position information setting unit38-2and the second target position adjustment unit48-2may correct at least one of the second relative position or the second target position based on at least one of the first relative position or the first target position, as described later inFIG.12. The second target position adjustment unit48-2may correct the second target position in the second drive range in accordance with the first target position corrected in the first target position adjustment unit48-1. Specific methods of calculation and correction will be described later.

The first control unit54-1obtains the first relative position and the first target position in the first drive range from the first position information setting unit38-1and the first target position adjustment unit48-1. The first control unit54-1outputs a signal for controlling the first magnetic field generation unit34-1based on the first relative position and the first target position. The first control unit54-1may output a signal based on a difference between the first relative position and the first target position. For example, the first control unit54-1outputs a signal for moving the movable body10by a distance according to the difference in a direction in which the difference decreases. The signal is converted into an analog signal in the first D/A unit56-1, and is outputted to the first driver58-1. The first driver58-1drives the movable body10in the first direction based on the signal inputted from the first D/A unit56-1in accordance with the first relative position of the movable body10in the first direction

The first driver58-1drives the movable body10by changing a magnetic field generated for the first magnet32-1in the first magnetic field generation unit34-1based on the signal.

Similarly, the second control unit54-2obtains the second relative position and the second target position in the second drive range from the second position information setting unit38-2and the second target position adjustment unit48-2. The second control unit54-2outputs a signal for controlling the second magnetic field generation unit34-2based on the second relative position and the second target position. The second control unit54-2may output a signal based on a difference between the second relative position and the second target position. The signal is converted into an analog signal in the second D/A unit56-2, and is outputted to the second driver58-2. The second driver58-2drives the movable body10in the second direction based on the second relative position of the movable body10in the second direction. The second driver58-2changes a magnetic field generated for the second magnet32-2in the second magnetic field generation unit34-2based on the signal. The IC chip70-1in the present example calculates and corrects positions of the movable body10in the Z axis direction as the first direction and in the X axis direction as the second direction, but the first direction and the second direction are not limited to this.

FIG.8shows exemplary configurations of the first arithmetic operation unit36-1and the second arithmetic operation unit36-2. The first arithmetic operation unit36-1has an adding circuit37-1and a dividing circuit37-3. The second arithmetic operation unit36-2has a subtracting circuit37-2. In the present example, the first arithmetic operation unit36-1calculates a position of the movable body10in a first direction based on a sum of/a difference between, the first magnetic field strength and the second magnetic field strength. In the present example, the second arithmetic operation unit36-2calculates a position of the movable body10in a second direction based on the difference between the first magnetic field strength and the second magnetic field strength. In the present example, the IC chip70-1has the first magnetic sensor72-1and the second magnetic sensor72-2. It should be noted that illustration of the AMP22, the A/D unit24, and the temperature sensor26is omitted inFIG.8.

The first magnetic sensor72-1outputs a signal according to the first magnetic field strength to the adding circuit37-1and the subtracting circuit37-2. Similarly, the second magnetic sensor72-2outputs a signal according to the second magnetic field strength to the adding circuit37-1and the subtracting circuit37-2. The adding circuit37-1takes the sum of the first magnetic field strength and the second magnetic field strength, and outputs a sum signal to the dividing circuit37-3. The subtracting circuit37-2takes the difference between the first magnetic field strength and the second magnetic field strength, and outputs a difference signal to the dividing circuit37-3and the second position information setting unit38-2. The difference signal branches at a branch point VHE_2, and is outputted to the first position information setting unit38-1as well. The dividing circuit37-3divides the sum signal by the difference signal, and outputs the divided signal to the first position information setting unit38-1. The divided signal branches at a branch point VHE_1, and is outputted to the second position information setting unit38-2as well.

FIG.9shows other exemplary configurations of the first arithmetic operation unit36-1and the second arithmetic operation unit36-2. The first arithmetic operation unit36-1in the present example has two adding circuits37-1and the dividing circuit37-3. The second arithmetic operation unit36-2in the present example has the adding circuit37-1and the subtracting circuit37-2. In the present example, the IC chip70-1has the first magnetic sensor72-1, the second magnetic sensor72-2, a third magnetic sensor72-3, and a fourth magnetic sensor72-4. It should be noted that the illustration of the AMP22, the A/D unit24, and the temperature sensor26is omitted inFIG.9as well.

The first magnetic sensor72-1outputs a signal according to a first magnetic field strength to a first adding circuit37-1of the first arithmetic operation unit36-1. Similarly, the second magnetic sensor72-2outputs a signal according to a second magnetic field strength to the first adding circuit37-1of the first arithmetic operation unit36-1. The third magnetic sensor72-3outputs a signal according to a third magnetic field strength detected by the third magnetic sensor72-3to the adding circuit37-1of the second arithmetic operation unit36-2. The fourth magnetic sensor72-4outputs a signal according to a fourth magnetic field strength detected by the fourth magnetic sensor72-4to the adding circuit37-1of the second arithmetic operation unit36-2.

The first adding circuit37-1of the first arithmetic operation unit36-1takes a sum of the first magnetic field strength and the second magnetic field strength, and outputs a sum signal to a second adding circuit37-1of the first arithmetic operation unit36-1and the subtracting circuit37-2of the second arithmetic operation unit36-2. The adding circuit37-1of the second arithmetic operation unit36-2takes a sum of the third magnetic field strength and the fourth magnetic field strength, and outputs a sum signal to the second adding circuit37-1of the first arithmetic operation unit36-1and the subtracting circuit37-2of the second arithmetic operation unit36-2.

The second adding circuit37-1of the first arithmetic operation unit36-1takes a sum of the sum signal outputted from the first adding circuit37-1of the first arithmetic operation unit36-1and the sum signal outputted from the adding circuit37-1of the second arithmetic operation unit36-2, and outputs a sum signal to the dividing circuit37-3of the first arithmetic operation unit36-1. The subtracting circuit37-2of the second arithmetic operation unit36-2takes a difference between the sum signal outputted from the first adding circuit37-1of the first arithmetic operation unit36-1and the sum signal outputted from the adding circuit37-1of the second arithmetic operation unit36-2, and outputs a difference signal to the dividing circuit37-3of the first arithmetic operation unit36-1and the second position information setting unit38-2. The difference signal branches at the branch point VHE_2, and is outputted to the first position information setting unit38-1as well.

The dividing circuit37-3of the first arithmetic operation unit36-1divides the sum signal from the second adding circuit37-1of the first arithmetic operation unit36-1by the difference signal from the subtracting circuit37-2of the second arithmetic operation unit36-2, and outputs the divided signal to the first position information setting unit38-1. The divided signal branches at the branch point VHE_1, and is outputted to the second position information setting unit38-2as well.

Similar processing may be performed even if there are four or more magnetic sensors72. The number of magnetic sensors72may be an odd number. For example, if there are three magnetic sensors72, the second arithmetic operation unit36-2does not need to have the adding circuit37-1.

FIG.10illustrates correction for an influence of a position on another axis.FIG.10corrects the influence of the position of the movable body10in the Z axis direction on the position in the X axis direction for a case ofFIG.6. Description duplicated with the description inFIG.6will be omitted. In addition, for illustrative purpose, the influence of the position on another axis is illustrated in an exaggerated manner. InFIG.10, an arithmetic operation result of a magnetic field in the arithmetic operation unit36is referred to as M1. If M1is collated with data for a case where the position in the Z axis direction is at an origin (a solid line in the figure), the position of the movable body10in the X axis direction is calculated as Z1. If the position of the movable body10in the Z axis direction is at the origin, there is no problem because a correct position has been calculated. However, for example, if the position in the Z axis direction is at +300 μm, data representing a relationship between the position of the movable body10in the X axis direction and an arithmetically operated magnetic field is as indicated by a dotted line in the figure, and is deviated from data for a case where the position of the movable body10in the X axis direction is at the origin. In this manner, if the position of the movable body10in the X axis direction is calculated by using the data for a case where the position in the Z axis direction is at the origin (the solid line inFIG.10) when the position in the Z axis direction is not at the origin, the position in the X axis direction, which is actually Z2, is calculated as Z1, for example.

In order to correct an error due to this position on another axis, the first position information setting unit38-1and the second position information setting unit38-2may hold the data representing the relationship between the position in the X axis direction and the arithmetically operated magnetic field for each position on another axis, and select the data to be referenced in accordance with an actual position of the movable body10on another axis.

As another example, the first position information setting unit38-1and the second position information setting unit38-2perform correction by adjusting a position of an end point of a drive range. The first position information setting unit38-1and the second position information setting unit38-2may set the drive range, and calculate a position of the movable body10as a relative position with respect to the drive range. The relative position with respect to the drive range refers to a position within the drive range. The relative position with respect to the drive range may mean, for example, a distance between at least one of a lower limit position or an upper limit position of the drive range and the position of the movable body10, or may mean a ratio of the distance to a length of the drive range. At this time, the position of the movable body10may be indicated by using a position code assigned to each position within the drive range.

InFIG.10, coordinate axes for a case where the position of the movable body10in the Z axis direction is at an origin are referred to as a “position code”, and coordinate axes for a case where the position of the movable body10in the Z axis direction is at +300 μm are referred to as a “position code′”. In the present example, a lower limit of the drive range in the “position code” is defined as a value corresponding to an arithmetically operated magnetic field MN at a lower limit of a movable range for a case where the position of the movable body10in the Z axis direction is at the origin, and an upper limit of the drive range in the “position code” is defined as a value corresponding to an arithmetically operated magnetic field MP at un upper limit of the movable range for a case where the position of the movable body10in the Z axis direction is at the origin. Similarly, the lower limit of the drive range in the “position code′” is defined as a value corresponding to an arithmetically operated magnetic field MN′ at the lower limit of the movable range for a case where the position of the movable body10in the Z axis direction is +300 μm, and the upper limit of the drive range in the “position code′” is defined as a value corresponding to an arithmetically operated magnetic field MP′ at the upper limit of the movable range for a case where the position of the movable body10in the Z axis direction is at +300 μm. A position D1in the “position code” in the figure corresponds to an arithmetically operated magnetic field M1for a case where the position of the movable body10in the Z axis direction is at the origin, and a position D1′ in the “position code′” corresponds the arithmetically operated magnetic field M1for a case where the position of the movable body10in the Z axis direction is at +300 μm. In the present correction method, the influence of the position on another axis is corrected by adjusting end point information of the drive range and calculating a relative position of the arithmetically operated magnetic field in the drive range without directly correcting a value of the arithmetically operated magnetic field.

Similarly, calculation and correction of a target position may be performed by updating the end point of the drive range. First, the target position may be calculated by converting the received target position into the target position in the drive range by using the position code assigned to each position within the drive range in the figure. Next, the correction may be performed by updating the end point of the drive range in accordance with the position of the movable body10on another axis if the target position in the drive range is calculated from the received target position.

FIG.11illustrates an example of calculation and correction of a target position for an influence of a position on another axis. The horizontal axis inFIG.11represents a position code, and the vertical axis represents a position of the movable body10in the X axis direction. A solid line in the figure indicates a case where a position of the movable body10in the Z axis direction is at an origin, and a dotted line indicates a case where the position of the movable body10in the Z axis direction is at +300 μm.FIG.11shows a case where the IC chip70-1controls the position of the movable body10. Description of terms or symbols similar to those inFIG.10will be omitted. Similarly toFIG.10, a curve for a case where the position in the Z axis direction is at +300 μm is shifted as compared to a curve for a case where the position in the Z axis direction is at the origin, and when the position code becomes equal to or greater than a certain value (a point F in the figure), the position of the movable body10becomes saturated, and then shows a constant value. Therefore, unless end point information of a drive range is updated for each position on another axis, a problem arises that the movable body10is not driven to an end at a position code0. In addition, a problem arises that the movable body10is not driven any further in a range where the position code is great (equal to or greater than the point F in the figure).

In order to correct the influence of this position on another axis, the first position information setting unit38-1and the second position information setting unit38-2may adjust an end point of the drive range. An adjustment method may be similar to the method described inFIG.10. InFIG.11, the dotted line is extended to a negative region on the horizontal axis “position code”, a point where the dotted line intersects the horizontal axis is referred to as E, and the point E is set as a lower limit of the end point of the drive range for a case where the position of the movable body10in the Z axis direction is at +300 μm. In addition, a point F where the dotted line starts to show the constant value is set as an upper limit of the end point of the drive range for a case where the position of the movable body10in the Z axis direction is at +300 μm. The first position information setting unit38-1and the second position information setting unit38-2calculate and correct the target position by converting the received target position into a relative position in the drive range according to the position on another axis described above.

FIG.14shows another exemplary configuration of the IC chip70-1. The IC chip70-1inFIG.14has a third arithmetic operation unit36-3, a third position information setting unit38-3, a third target position obtainment unit46-3, a third target position adjustment unit48-3, a third control unit54-3, a third D/A unit56-3, and a third driver58-3in addition to any one of the configurations shown inFIGS.7,12, and13. In addition, the camera module100has a third magnetic field generation unit and the third magnet32-3.

The IC chip70-1in the present example is configured to detect a position of the movable body in a third direction in addition to a first direction and a second direction. The third direction may be the Y axis direction. The first magnet32-1may have a third portion adjacent to the first portion41or to the second portion42in the third direction. The IC chip70-1may have a third magnetic sensor. The third magnetic sensor may be arranged side by side with a first magnetic sensor or a second magnetic sensor in the third direction. As in the first direction, the IC chip70-1may detect a position of the movable body10in the third direction based on a sum of or the sum of/a difference between, a first magnetic field strength or a second magnetic field strength and a third magnetic field strength which is detected by the third magnetic sensor.

The second position information selection unit64-2obtains a result in the second arithmetic operation unit36-2and a second target position from the second target position obtainment unit46-2. The second position information selection unit64-2decides which of the result in the second arithmetic operation unit36-2and the second target position which have been obtained is to be used as second position information.

The first position information storage unit66-1stores the first position information decided in the first position information selection unit64-1. The first position information storage unit66-1may have a register memory. The second position information storage unit66-2stores the second position information decided in the second position information selection unit64-2. The second position information storage unit66-2may have a register memory. The first position information setting unit38-1and the first target position adjustment unit48-1may obtain the second position information stored in the second position information storage unit66-2. The second position information setting unit38-2and the second target position adjustment unit48-2may obtain the first position information stored in the first position information storage unit66-1. The first position information setting unit38-1may update end point information of a first drive range in a first direction in accordance with the second position information. The second position information setting unit38-2may update end point information of a second drive range in a second direction in accordance with the first position information.

When performing correction in a direction perpendicular to an optical axis of light entering the optical element20, the first position information setting unit38-1may correct a first relative position based on a second relative position. When performing correction in a direction parallel to the optical axis of the light entering the optical element20, the first target position adjustment unit48-1may correct the first target position based on the second target position. Position information (a result in the arithmetic operation unit36) is characterized in that it is updated at shorter intervals than target position information. For example, in a case where it is necessary to quickly follow up a change in a position such as image stabilization, the first position information selection unit64-1and the second position information selection unit64-2may select the result in the arithmetic operation unit36as the position information. On the other hand, in a case where a follow-up interval is relatively long such as when a focal position is controlled, the target position information updated less frequently may be selected as the position information.

FIG.17shows an exemplary configuration of the first position information setting unit38-1. First position information Vip_1indicating a detection position of the movable body10in a first direction and second position information Vip_2indicating a detection position of the movable body10in a second direction are inputted to the first position information setting unit38-1. The first position information setting unit38-1has a first another-axis motion monitor unit74, a first upper limit end point information arithmetic operation unit78-1, a register memory unit80-1, a basic upper limit end point information unit82-1, a first upper limit end point information unit76-1, a first lower limit end point information arithmetic operation unit78-2, a register memory unit80-2, a basic lower limit end point information unit82-2, a first lower limit end point information unit76-2, a subtractor84-1, a subtractor84-2, a divider86, and an integrator88. The first another-axis motion monitor unit74may monitor a motion on another axis. An another-axis motion monitor unit determines whether the movable body10is in motion or at rest in a direction other than the first direction. The first another-axis motion monitor unit74in the present example monitors a motion of the movable body10in the second direction based on the second position information. The second position information may be a second relative position outputted by the second position information setting unit38-2. After determining whether the movable body10is in motion or at rest in the second direction, the first another-axis motion monitor unit74transmits the second position information to the first upper limit end point information arithmetic operation unit78-1and the first lower limit end point information arithmetic operation unit78-2. The first position information setting unit38-1decides whether a first relative position or a first target position is to be corrected based on determination of the another-axis motion monitor unit. The first position information setting unit38-1may update end point information by considering information on the motion on another axis. If the information on the motion on another axis indicates that the movable body10is in motion, the first position information setting unit38-1may suspend updating the end point information until the movable body10is at rest. Even if the information on the motion on another axis indicates that the movable body10is in motion, the first position information setting unit38-1may update the end point information.

The register memory unit80-1previously obtains and stores a parameter for calculating the first relative position. The register memory unit80-1may store end point information according to the position on another axis. The end point information may be stored for each position on another axis. The end point information may be obtained by approximating finite end point information at different positions on another axis by using an approximate expression, or may be a parameter of the approximate expression. The end point information may be listed. The parameter may be generated and updated after the IC chip70-1is mounted. The basic upper limit end point information unit82-1stores the end point information for a case where a position of the movable body10on another axis is at an origin. The first upper limit end point information arithmetic operation unit78-1arithmetically operates an upper limit of a first drive range by using the second relative position and the information which is stored in the register memory unit80-1, and outputs a result to the first upper limit end point information unit76-1. The first upper limit end point information arithmetic operation unit78-1may arithmetically operate an upper limit PCAL of the first drive range by using the information in the basic upper limit end point information unit82-1as well. The first upper limit end point information unit76-1decides the upper limit PCAL of the first drive range.

The register memory unit80-2previously obtains and stores a parameter for calculating the first relative position. The register memory unit80-2and the basic lower limit end point information unit82-2stores the same information as the information in the register memory unit80-1and the basic upper limit end point information unit82-1. The first lower limit end point information arithmetic operation unit78-2arithmetically operates a lower limit of the first drive range by using the second relative position and the information which is stored in the register memory unit80-1, and outputs a result to the first lower limit end point information unit76-2. The first lower limit end point information arithmetic operation unit78-2may arithmetically operate a lower limit NCAL of the first drive range by using the information in the basic lower limit end point information unit82-2as well. The first lower limit end point information unit76-2decides the lower limit NCAL of the first drive range.

The subtractor84-2calculates a first difference PCAL−NCAL between the upper limit PCAL and the lower limit NCAL of the first drive range. The first difference corresponds to a size of the first drive range. The subtractor84-1calculates a second difference Vip_1−NCAL between the first position information Vip_1and the lower limit NCAL of the first drive range. The second difference corresponds to a distance between a position of the lower limit NCAL of the first drive range and a position of the movable body10in the first direction. The divider86calculates a value obtained by dividing the second difference Vip_1−NCAL by the first difference PCAL−NCAL. The value corresponds to a relative position of the movable body10in the first drive range.

The integrator88receives an output signal from the divider86, and outputs VPROC_1=(Vip_1−NCAL)/(PCAL−NCAL)×511. 511 is a numerical value indicating 29−1. This “511” may be arbitrarily changed depending on the upper limit PCAL and the lower limit NCAL of the first drive range.

The second position information setting unit38-2may have the same configuration as that of the first position information setting unit38-1. Similarly to the first position information setting unit38-1, the second position information setting unit38-2may decide whether to correct the second relative position based on determination of the another-axis motion monitor unit. Similarly to the first position information setting unit38-1, the second position information setting unit38-2may arithmetically operate an upper limit and a lower limit of a second drive range.

FIG.18shows exemplary configurations of the first target position adjustment unit48-1and the second target position adjustment unit48-2. The first target position adjustment unit48-1includes a first linear arithmetic operation unit92-1, a register memory unit94-1, a basic linear correction unit96-1, and a first linear correction unit90-1. The second target position adjustment unit48-2includes a second linear arithmetic operation unit92-2, a register memory unit94-2, a basic linear correction unit96-2, and a second linear correction unit90-2.

The IC chip70-1may further include the first linear correction unit90-1and the second linear correction unit90-2. The first linear correction unit90-1in the present example is arranged inside the first target position adjustment unit48-1, and the second linear correction unit90-2is arranged inside the second target position adjustment unit48-2. The first linear correction unit90-1may be arranged inside the first position information setting unit38-1, and the second linear correction unit90-2may be arranged inside the second position information setting unit38-2. The first linear correction unit90-1may correct variations in magnetic fields detected by the plurality of magnetic sensors72in a first drive range, and a first relative position or a first target position of the movable body10. The second linear correction unit90-2may correct variations in magnetic fields detected by the plurality of magnetic sensors72in a second drive range, and a second relative position or a second target position of the movable body10.

The first linear arithmetic operation unit92-1obtains the second target position from the second target position obtainment unit46-2. In addition, information obtained by the first linear arithmetic operation unit92-1may be the second relative position. The first linear arithmetic operation unit92-1derives a new linear correction value from the parameters stored in the register memory unit94-1and the basic linear correction unit96-1based on the obtained second target position, and outputs it to the first linear correction unit90-1.

The first linear correction unit90-1performs correction based on the second target position. In the present example, the first linear correction unit90-1performs correction based on the new linear correction value derived based on the second target position.

Similar processing is performed in the second target position adjustment unit48-2. The second linear arithmetic operation unit92-2derives a new linear correction value based on the first target position, and outputs it to the second linear correction unit90-2. The second linear correction unit90-2performs correction based on at least one of the first relative position or the first target position. In the present example, the second linear correction unit90-2performs correction based on the new linear correction value derived based on the first target position.

FIG.19shows other exemplary configurations of the first target position adjustment unit48-1and the second target position adjustment unit48-2. The IC chip70-1in the present example has a first another-axis motion monitor unit74-1and a second another-axis motion monitor unit74-2in addition to the configuration described inFIG.18. The first another-axis motion monitor unit74-1and the second another-axis motion monitor unit74-2may be provided inside the first target position adjustment unit48-1and the second target position adjustment unit48-2. In the present example, the first another-axis motion monitor unit74-1and the second another-axis motion monitor unit74-2are provided short of the first target position obtainment unit46-1and the second target position46-2.

The first another-axis motion monitor unit74-1and the second another-axis motion monitor unit74-2may select whether a target position on an own axis is to be updated based on information on a position on another axis including a relative position. The first another-axis motion monitor unit74-1in the present example selects whether a first target position is to be updated based on a second relative position. The second another-axis motion monitor unit74-2in the present example selects whether a second target position is to be updated based on a first relative position.

FIG.20shows other exemplary configurations of the first target position adjustment unit48-1and the second target position adjustment unit48-2. The first target position adjustment unit48-1may include a first drive range adjustment unit98-1, a first drive range arithmetic operation unit102-1, a register memory unit104-1, and a basic drive range correction unit106-1in addition to the configuration inFIG.18orFIG.19. The second target position adjustment unit48-2may include a second drive range adjustment unit98-2, a second drive range arithmetic operation unit102-2, a register memory unit104-2, and a basic drive range correction unit106-2in addition to the configuration inFIG.18orFIG.19.

The register memory unit104-1may store end point information according to the position on another axis. The end point information may be stored for each position on another axis. The end point information may be obtained by approximating finite end point information at different positions on another axis by using an approximate expression, or may be a parameter of the approximate expression. The end point information may be listed. The parameter may be generated and updated after the IC chip70-1is mounted. The basic drive range correction unit106-1stores the end point information for a case where a position of the movable body10on another axis is at an origin.

The first drive range arithmetic operation unit102-1obtains a second target position. The first linear arithmetic operation unit92-1derives new end point information from the end point information or the parameters stored in the register memory unit104-1and the basic linear correction unit96-1based on the obtained second target position, and outputs it to the first drive range adjustment unit98-1.

The first drive range adjustment unit98-1adjusts a first drive range. The first drive range adjustment unit98-1may adjust the first drive range based on at least one of a second relative position or a second target position. The first drive range adjustment unit98-1in the present example adjusts the first drive range based on the second target position. The first drive range adjustment unit98-1may shift the first drive range set by the first position information setting unit38-1. Instead of the first position information setting unit38-1updating the first drive range, the first drive range adjustment unit98-1may adjust the first drive range.

Similar processing is performed in the second target position adjustment unit48-2. The second drive range arithmetic operation unit102-2derives the new end point information based on a first target position. The second drive range adjustment unit98-2adjusts a second drive range. The second drive range adjustment unit98-2may adjust the second drive range based on at least one of a first relative position or the first target position. The second drive range adjustment unit98-2in the present example adjusts the second drive range based on the first target position. The second drive range adjustment unit98-2may adjust, as the second drive range, a range narrower than the second drive range set by the second position information setting unit38-2. Instead of the second position information setting unit38-2updating the second drive range, the second drive range adjustment unit98-2may adjust the second drive range.

FIG.21shows other exemplary configurations of the first target position adjustment unit48-1and the second target position adjustment unit48-2. The first target position adjustment unit48-1in the present example includes a first temperature characteristic correction unit108-1, a first temperature characteristic correction arithmetic operation unit110-1, a register memory unit112-1, and a temperature sensor114-1in addition to the configuration inFIG.20. The second target position adjustment unit48-2in the present example includes a second temperature characteristic correction unit108-2, a second temperature characteristic correction arithmetic operation unit110-2, a register memory unit112-2, and a temperature sensor114-2in addition to the configuration inFIG.20.

A rise in temperature inside the movable body10changes a temperature characteristic of a lens and a temperature characteristic of a magnet which are included in the movable body10, so it is desirable to correct that influence. The register memory unit112-1may store temperature characteristic information according to a position on another axis. The information may be stored for each position on another axis. The information may be obtained by approximating finite information at different positions on another axis by using an approximate expression, or may be a parameter of the approximate expression. The information may be listed. The parameter may be generated and updated after the IC chip70-1is mounted. The temperature sensor114-1measures temperature of the IC chip70-1during operation. Without the temperature sensor114-1being included in the first target position adjustment unit48-1, information from a temperature sensor located outside the IC chip70-1may be written into the register memory unit112-1.

The first temperature characteristic correction arithmetic operation unit110-1obtains a second target position. In addition, information obtained by the first temperature characteristic correction arithmetic operation unit110-1may be a second relative position. The first temperature characteristic correction arithmetic operation unit110-1derives new end point information from temperature information and a temperature characteristic which is stored in the register memory unit112-1based on the obtained second target position, and outputs it to the first temperature characteristic correction unit108-1.

The first temperature characteristic correction unit108-1adjusts a first drive range based on the second target position. The first temperature characteristic correction unit108-1may adjust the first drive range based on the new end point information obtained from the first temperature characteristic correction arithmetic operation unit110-1. The first temperature characteristic correction unit108-1in the present example adjusts the first drive range based on the second target position. Similarly, the second temperature characteristic correction unit108-2adjusts a second drive range based on at least one of a first relative position or a first target position. The second temperature characteristic correction unit108-2in the present example adjusts the second drive range based on the first target position. The second temperature characteristic correction unit108-2may adjust the second drive range based on the new end point information obtained from the second temperature characteristic correction arithmetic operation unit110-2. This allows correction of changes in the temperature characteristic of the lens and the temperature characteristic of the magnet due to a change in the temperature inside the movable body10.

FIG.22illustrates a terminal arrangement of the IC chip70-1. Any one of the IC chips70-1inFIGS.1to21may have the terminal arrangement shown inFIG.22. The IC chip70-1has terminals116-1to116-6. The terminal arrangement of the IC chip70-1in the present example is a staggered arrangement. In the IC chip70-1in the present example, a position of one terminal is arranged at a position different from a position of another terminal in a shorter direction of the IC chip70-1.

Arranging the terminals in a staggered manner can increase a distance between the adjacent terminals116-1and116-2(A in the figure) as compared to a case where the terminals are arranged in a normal lattice pattern, which can increase a degree of freedom in rewiring. In addition, since there are no terminals116-1to116-6in the shorter direction as well, there is an advantage that wiring lines can be easily run. While it is difficult, especially in a latticed arrangement, to run the wiring lines from the terminals along a longer direction, it is easy, in the staggered arrangement, to lay the wiring lines in the longer direction because distances between the terminals116-1to116-6are wider than in the latticed arrangement, which can increase a degree of freedom in design.

FIG.23is a perspective view showing an example of a position control system200according to another embodiment of the present invention. The position control system200may include at least some of configurations other than the optical element20, among the configurations of the camera module100described inFIG.1toFIG.22. The position control system200in the present example includes all of the configurations other than the optical element20, among the configurations of the camera module100. Functions or the like of the configurations included in the position control system200are similar to those of the camera module100described inFIG.1toFIG.22. The position control system200may also be used for applications other than a camera.

While the present invention has been described by using the embodiments, the technical scope of the present invention is not limited to the scope described in the above-described embodiments. It is apparent to persons skilled in the art that various alterations or improvements can be added to the above-described embodiments. It is also apparent from the description of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

It should be noted that the operations, procedures, steps, stages, and the like of each processing performed by an apparatus, system, program, and method shown in the claims, specification, or drawings can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous processing is not used in a later processing. Even if the operation flow is described using phrases such as “first” or “next” for the sake of convenience in the claims, specification, or drawings, it does not necessarily mean that the process must be performed in this order.

EXPLANATION OF REFERENCES

10: movable body,12: surface,12-1: first surface,12-2: second surface,12-3: third surface,12-4: fourth surface,14: fixed portion,16: surface,16-1: first surface,16-2: second surface,16-3: third surface,16-4: fourth surface,20: optical element,22: AMP,24: A/D unit,26: temperature sensor,30: drive unit,30-1: first drive unit,30-2: second drive unit,30-3: third drive unit,32: magnet,32-1: first magnet,32-2: second magnet,32-3: third magnet,34: magnetic field generation unit,34-1: first magnetic field generation unit,34-2: second magnetic field generation unit,34-3: third magnetic field generation unit,36: arithmetic operation unit,36-1: first arithmetic operation unit,36-2: second arithmetic operation unit,36-3: third arithmetic operation unit,37-1: adding circuit,37-2: subtracting circuit,37-3: dividing circuit,38-1: first position information setting unit,38-2: second position information setting unit,38-3: third position information setting unit,41: first portion,42: second portion,44: target position reception unit,46-1: first target position obtainment unit,46-2: second target position obtainment unit,46-3: third target position obtainment unit,48-1: first target position adjustment unit,48-2: second target position adjustment unit,48-3: third target position adjustment unit,54-1: first control unit,54-2: second control unit,54-3: third control unit,56-1: first D/A unit,56-2: second D/A unit,56-3: third D/A unit,58-1: first driver,58-2: second driver,58-3: third driver,61: first portion,64-1: first position information selection unit,64-2: second position information selection unit,66-1: first position information storage unit,66-2: second position information storage unit,70: IC chip,70-1: IC chip,70-2: IC chip,71: position detection unit,72: magnetic sensor,72-1: first magnetic sensor,72-2: second magnetic sensor,74: first another-axis motion monitor unit,74-1: first another-axis motion monitor unit,74-2: second another-axis motion monitor unit,76-1: first upper limit end point information unit,76-2: first lower limit end point information unit,78-1: first upper limit end point information arithmetic operation unit,78-2: first lower limit end point information arithmetic operation unit,80-1: register memory unit,80-2: register memory unit,82-1: basic upper limit end point information unit,82-2: basic lower limit end point information unit,84-1: subtractor,84-2: subtractor,86: divider,88: integrator,90-1: first linear correction unit,90-2: second linear correction unit,92-1: first linear arithmetic operation unit,92-2: second linear arithmetic operation unit,94-1: register memory unit,94-2: register memory unit,96-1: basic linear correction unit,96-2: basic linear correction unit,98-1: first drive range adjustment unit,98-2: second drive range adjustment unit,100: camera module,102-1: first drive range arithmetic operation unit,102-2: second drive range arithmetic operation unit,104-1: register memory unit,104-2: register memory unit,106-1: basic drive range correction unit,106-2: basic drive range correction unit,108-1: first temperature characteristic correction unit,108-2: second temperature characteristic correction unit,110-1: first temperature characteristic correction arithmetic operation unit,110-2: second temperature characteristic correction arithmetic operation unit,112-1: register memory unit,112-2: register memory unit,114-1: temperature sensor,114-2: temperature sensor,116-1: terminal,116-2: terminal,116-3: terminal,116-4: terminal,116-5: terminal,116-6: terminal.