JP2008180561A - Position detection circuit and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detection circuit and an imaging device using the same capable of position detection with high precision by correcting the temperature performance of magnetic field change detection element. <P>SOLUTION: The position detection circuit for detecting the relative positional relation between the plurality of Hall elements and the magnetic field generation means based on the subtraction amplifying results is constituted of: a plurality of Hall elements 101a, 101b arranged with a prescribed interval; a magnetic field generation means 106 for generating the magnetic field corresponding to the input current; a subtraction amplifying means 102 for subtracting each output from the plurality of Hall elements; an additional amplifying means 103 for adding each of output of the plurality of Hall elements; a control value generation means 104 for restricting the difference between the reference voltage 104b and additional results of the additional amplifying means; and a V-I converting means 105 for converting the control value of the control value generation means into current and outputs as the input current of the magnetic field generation means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a position detection circuit that detects a relative position between objects, and an imaging apparatus using the position detection circuit.

  Conventionally, as a method for detecting the relative position between objects, a position detection method using a permanent magnet and a Hall element (magnetic field change detection element) is often used from the viewpoint of relatively low cost. Particularly recently, in an imaging device such as a camera, the correction lens and the imaging device are perpendicular to the optical axis of the incident light so as to cancel out the shake according to the amount and direction of camera shake caused by the photographer during shooting. It is used in a correction lens for a shake correction device that translates and corrects a shake and a position detection device for an image sensor.

Conventionally, Japanese Patent Laid-Open No. 2005-242327 (Patent Document 1) discloses a position for detecting the position of an image sensor in a shake correction apparatus that performs the shake correction by translationally driving the correction lens and the image sensor as described above. A configuration in which a coil is used for the detection magnetic field generation unit and a Hall element is used for the magnetic field change detection element is disclosed. In this disclosure, only when position detection is performed, the coil is energized, and the coil is magnetized to reduce the resistance when the image sensor is translated.
JP 2005-242327 A JP 2005-331399 A

  However, since the Hall element usually has temperature characteristics, when the environmental temperature changes, there is a problem that the sensitivity of the Hall element changes and the position detection accuracy decreases. Is not considered from the viewpoint of corresponding to the temperature characteristics of the Hall element. On the other hand, Japanese Patent Laying-Open No. 2005-331399 (Patent Document 2) discloses that temperature compensation is performed by changing the input voltage applied to the Hall element in accordance with the temperature change. However, it is necessary to adjust the applied input current for each Hall element, and control is not easy.

  Therefore, in order to perform position detection with higher accuracy, a correction method and a position detection method that can easily correct the temperature characteristics of the Hall element are desirable. An object of the present invention is to provide a position detection circuit capable of performing position detection with high accuracy by correcting the temperature characteristics of the magnetic field change detection element in position detection using the magnetic field change detection element, and a shake correction function using the position detection circuit. It is providing the imaging device provided with.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a plurality of magnetic field change detecting elements arranged at a predetermined interval, a magnetic field generating means for generating a magnetic field according to an input current, and the plurality of magnetic fields. A position detecting circuit that subtracts each output from the change detecting element and detects a relative positional relationship between the plurality of magnetic field change detecting elements and the magnetic field generating means based on a subtraction result of the subtracting means. An addition unit that adds outputs from the plurality of magnetic field change detection elements, a control value generation unit that generates a control value that suppresses a difference between a reference value and an addition result of the addition unit, and the control value Conversion means for converting the control value of the generating means into a current and outputting it as an input current of the magnetic field generating means.

  In the position detection circuit configured as described above, an addition signal and a subtraction signal are generated from outputs of a plurality of magnetic field change detection elements, and a control value that suppresses a difference between the addition signal and a reference value is converted into a current to generate a magnetic field. By feeding back to the means, the magnetic field of the magnetic field generating means is controlled so that the addition signal becomes constant, and the subtraction signal is output as a position signal.

  According to a second aspect of the present invention, in the position detection circuit according to the first aspect, the magnetic field generating means is a coil.

  An embodiment corresponding to the second aspect of the present invention is the first embodiment. In the position detection circuit configured as described above, the coil is magnetized by the control value converted into the current to generate a magnetic force at the time of position detection.

  According to a third aspect of the present invention, in the position detection circuit according to the first aspect, the magnetic field generating means includes a coil and a permanent magnet.

  An embodiment corresponding to the third aspect of the present invention is the second embodiment. In the position detection circuit configured as described above, the coil is magnetized by the control value converted into current based on the magnetic field of the permanent magnet, and the total magnetic field generated from the permanent magnet and the magnetic field generated from the coil is used for position detection. Let it be a magnetic field.

  According to a fourth aspect of the present invention, in the position detection circuit according to the third aspect, the coil and the permanent magnet have a rectangular shape, and the arrangement relationship thereof is that the coil is provided on the outer periphery of the permanent magnet, On the surface of the permanent magnet facing the magnetic field change detecting element, the point where the two diagonal lines of the coil intersect with the point where the two diagonal lines of the permanent magnet intersect with each other.

  An embodiment corresponding to the invention according to claim 4 is the second embodiment. In the position detection circuit configured as described above, the coil and the permanent magnet are arranged so that their centers coincide with each other on the surface facing the magnetic field change detection element.

  The invention according to claim 5 is a movable holding for holding either a photographing lens or an image sensor that converts an object image incident through the photographing lens into an electric signal so as to be movable with respect to a housing of the imaging device. A magnetic field generating means for generating a magnetic field, and the movable holding part or the housing facing the magnetic field generating means. A position detection circuit according to any one of claims 1 to 4 disposed on any one side surface of a member fixed to the body, and a shake amount measuring means for measuring a shake amount of the housing, The image pickup apparatus is configured to include movement control means for moving the movable holding unit so as to cancel out the shake amount based on an output from the position detection circuit.

  According to the first and second aspects of the invention, it is possible to easily suppress the influence of the position detection error due to the temperature characteristics of the magnetic field change detection element and to realize a position detection circuit with improved position detection accuracy. Further, according to the inventions according to claims 3 and 4, the position detection circuit can reduce power consumption at the time of position detection while ensuring the same position detection accuracy as the position detection circuit according to claims 1 and 2. Current can be achieved. In addition, according to the fifth aspect of the present invention, it is possible to easily suppress the influence of the position detection error due to the temperature characteristic of the magnetic field change detection element and perform the position detection of the image pickup element with high accuracy. Thus, it is possible to realize an image pickup apparatus having a shake correction function capable of performing shake correction.

  Next, the best mode for carrying out the present invention will be described.

  First, a first embodiment of the position detection circuit according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a position detection circuit according to the first embodiment. FIGS. 2 and 3 are a perspective view and a top view of a physical arrangement of components used for position detection according to the first embodiment. . Next, the configuration of the first embodiment will be described. Here, it is assumed that Hall elements 101a and 101b are used as the magnetic field change detecting elements, and a rectangular coil 107 having 4 turns is used as the magnetic field generating means 106.

  The position detection circuit according to this embodiment includes Hall elements 101a and 101b, a Hall element signal processing circuit 100, and magnetic field generation means 106, and one of the input terminals of the Hall elements 101a and 101b is connected to the power supply voltage Vcc, The other input terminal is connected to GND. The Hall element signal processing circuit 100 includes a subtracting amplification unit 102, an addition amplification unit 103, a control value generation unit 104, and a VI conversion unit 105. The control value generation unit 104 includes an integration unit 104a and a reference unit. The voltage 104b is used.

  Here, as shown in FIGS. 2 and 3, the Hall elements 101a and 101b are a set of Hall element pairs that are discretely arranged with a predetermined interval in the x-axis direction. The coil 107 has one terminal connected to the VI conversion means 105 and the other connected to the GND, and is attached to face the pair of Hall elements 101a and 101b. The coil 107 is used as a magnetic field generating means 106 for detecting the position, and a magnetic field corresponding to the current value of the supplied current and the flowing direction is generated only while the current is supplied to the coil 107. In this embodiment, as shown in FIGS. 2 and 3, the current supply direction is the direction in which the current flows from the VI converter circuit 105 through the coil 107 to the GND according to the direction of the arrow. The surface facing 101a and 101b is magnetized as an N pole and the opposite surface is magnetized as an S pole.

  The output signals Vha and Vhb of the pair of Hall elements 101a and 101b change according to the change of the magnetic field due to the movement of the coil 107. The subtracting amplifier 102 amplifies the difference between the output signals Vha and Vhb of the pair of Hall elements 101a and 101b by a gain α times that of the subtracting amplifier 102 and outputs the amplified signal as a position signal ΔV. The summing amplifier 103 amplifies the sum of the output signals Vha and Vhb of the pair of Hall elements 101a and 101b by a gain β times of the summing amplifier 103 and outputs the amplified signal. The integration means 104a receives the output signal of the addition amplification means 103 and a constant reference voltage 104b set to a predetermined value, and the integration means 104a outputs the output signal of the addition amplification means 103 based on the reference voltage 104b. Integrate. The integration result of the integration means 104a is input to the VI conversion means 105, the voltage value of the integration result is converted into a current value by the VI conversion means 105, and current is supplied to the coil 107.

  Next, the operation of the first embodiment configured as described above will be described. The output signals Vha and Vhb from the pair of Hall elements 101a and 101b are input to the subtraction amplification means 102 and the addition amplification means 103. The subtracting amplifier 102 amplifies the difference between the output signals Vha and Vhb of the pair of Hall elements 101a and 101b by a gain α times that of the subtracting amplifier 102 and outputs ΔV = α (Vha−Vhb) as a position signal. Further, the summing amplifier 103 amplifies the sum of the output signals Vha and Vhb of the pair of Hall elements 101a and 101b by a gain β times that of the summing amplifier 103, and outputs β (Vha + Vhb) to the integrator 104a. The integration means 104a receives the output signal β (Vha + Vhb) of the addition increase means 103 and a constant reference voltage 104b. The integration means 104a integrates the output signal of the addition amplification means 103 based on the reference voltage 104b, The integrated signal is output to the VI conversion means 105. The VI conversion means 105 converts the integration signal from voltage to current, feeds back the current to the coil 107, and adjusts the magnetic field applied to the pair of Hall elements 101a and 101b.

  More specifically, the magnetic field generated in the coil 107, that is, the current flowing through the coil 107, compares the reference voltage 104b with the output signal of the summing amplifier 103, and if the reference voltage 104b is larger, the current flowing through the coil 107 If the output signal of the summing amplifier 103 is larger than the reference voltage 104b, the feedback control is performed in the direction of decreasing the current flowing through the coil 107.

  Thus, the current flowing through the coil 107 is subtracted by feedback control so that the output signal of the adding and amplifying means 103 (the sum of Vha and Vhb multiplied by the gain) becomes constant by the output signal of the integrating means 104a. Adjustment can be performed so that the output signal ΔV of the amplifying means 102 is standardized, and the output signals of the pair of Hall elements 101a and 101b can be output as position signals with good linearity.

Next, feedback control is performed so that the output signal of the summing amplifier 103 becomes constant in this way, and the output signal of the subtracting amplification means 102 is output as a position signal, whereby the position due to the temperature characteristics of the pair of Hall elements 101a and 101b The fact that the influence of detection errors can be easily suppressed will be described. The output signals Vha and Vhb of the pair of Hall elements 101a and 101b when the environmental temperature is T and the coil 107 is at the predetermined position X can be expressed as the following equations (1) and (2).
Vha (T) = μ _H (T) × B _Ca (T) × Vcc (1)
Vhb (T) = μ _H (T) × B _Cb (T) × Vcc (2)

Here, μ _H (T) is the carrier mobility, B _Ca (T) and B _Cb (T) are the magnetic flux densities applied to the pair of Hall elements 101a and 101b, and Vcc is the pair of Hall elements 101a and 101b. Indicates the power supply voltage. Further, the magnetic flux density B _C (T) generated by the current flowing through the coil 107 can be expressed by the following equation (3).
B _C (T) = μ × n × I (T) / L [T] (3)

Here, μ is the permeability in the air, n is the number of turns of the coil, I (T) is the current flowing through the coil, and L is the length of the coil. Although the outputs of the pair of Hall elements 101a and 101b also change depending on the position X, they are omitted here to focus only on the influence of the temperature characteristics of the Hall elements due to the change of the environmental temperature. At this time, since the output signal of the addition amplification means 103 is controlled to be constant, the relationship of the addition signal under the ambient temperature T1 is expressed by the following equation (4).
Vha (T1) + Vhb (T1) = μ _H (T1) × Vcc × {B _Ca (T1) + B _Cb (T1)} = Vref1
μ _H (T1) × Vcc = Vref1 / {B _Ca (T1) + B _Cb (T1)} (4)

Here, Vref1 represents a reference voltage used as a predetermined value in the adding means. Further, the output signal (position signal) ΔV (T1) of the subtracting means 102 under the environmental temperature T1 is expressed by the following equation (5) using the equation (4).
ΔV (T1) = Vha (T1) −Vhb (T1)
= Vcc × μ _H (T1) × {B _Ca (T1) −B _Cb (T1)}
= {B _Ca (T1) -B _Cb (T1)} / {B _Ca (T1) + B _Cb (T1)} × Vref1
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ （5）
ΔV (T1) is a value obtained by normalizing {B _Ca (T1) −B _Cb (T1)} by {B _Ca (T1) + B _Cb (T1)}.

Similarly, when the output signal ΔV (T2) of the subtracting means 102 under different environmental temperatures T2 is obtained, ΔV (T2) is expressed as {B _Ca (T2) −B _Cb ( T2)} is normalized by {B _Ca (T2) + B _Cb (T2)}.
ΔV (T2) = {B _Ca (T2) −B _Cb (T2)} / {B _Ca (T2) + B _Cb (T2)} × Vref1
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ （6）
Therefore, ΔV (T1) and ΔV (T2) are values obtained by normalizing (B _Ca −B _Cb ) by (B _Ca + B _Cb ), and ΔV (T1) and ΔV (T2) are equal.

  From the above, according to the present embodiment, the position signal ΔV (T1) under the ambient temperature T1 is controlled by controlling the value of the current flowing through the coil 107 so that the output signal of the summing amplifier 103 is constant. The position signals ΔV (T2) under the environmental temperature T2 are equal, and it is possible to easily suppress position detection errors due to the temperature characteristics of the Hall elements. Therefore, the correction process can be easily performed without performing the operation for obtaining the parameter for correcting the error due to the temperature of the Hall element or the operation for correcting according to each device, and the position detection is performed with high accuracy. be able to.

  Next, a second embodiment of the present invention will be described. FIG. 4 is a block diagram illustrating a configuration of a position detection circuit according to the present embodiment, and FIGS. 5, 6, and 7 are front views of physical arrangements of components used for position detection according to the second embodiment. It is a perspective view and a top view. The elements constituting the Hall element and the Hall element signal processing circuit used in the second embodiment shown in FIG. 4 are the same as those in the first embodiment shown in FIG. Is omitted. Next, each configuration and operation of the present embodiment will be described with a focus on differences from the first embodiment. The difference between the second embodiment and the first embodiment is the magnetic field generating means 201. The magnetic field generating means 201 in the second embodiment includes a rectangular coil 107 and a permanent magnet 202, and the coil 107 is disposed on the outer periphery of the permanent magnet 202. The arrangement of the coil 107 and the permanent magnet 202 is such that the intersection of the diagonal line D1 and the diagonal line D2 on the surface of the coil 107 facing the Hall element and the intersection of the diagonal line D3 and the diagonal line D4 on the surface of the permanent magnet 202 facing the Hall element. They are arranged so as to coincide at C1 (the intersections of the diagonal lines of the coil 107 and the permanent magnet 202 coincide). Further, the terminal connected to the GND of the coil 107 in the first embodiment is connected to the reference voltage Vref2 in the second embodiment.

  In the first embodiment, the magnetic field for detecting the position is generated only by the current supplied to the coil 107, but the magnetic force generating means 201 is provided with the coil 107 and the permanent magnet 202 as in the second embodiment. In the configuration, the magnetic field for position detection is mainly generated by the permanent magnet 202, and the current supplied to the coil 107 generates a magnetic field for correcting the temperature characteristics of the pair of Hall elements 101a and 101b. Only a minute current is required. That is, according to the configuration of the magnetic field generating means 201 of the second embodiment, it is possible to reduce the current consumption related to position detection in the position detection circuit as compared with the first embodiment.

  Also, since the intersections of the diagonal lines of the coil 107 and the permanent magnet 202 coincide with each other, the magnetic field generated when only the coil 107 is used or the magnetic field when only the permanent magnet 202 is used is used. In addition, since the magnetic field is formed concentrically from the center of the coil 107 or the permanent magnet 202, the position can be detected with high accuracy as in the first embodiment. Further, since the characteristics of the permanent magnet 202 vary from individual to individual, it is conceivable that the position detection accuracy decreases due to the variation from individual to individual. However, in the position detection circuit according to the second embodiment, it is possible to correct the variation in the characteristics of the individual permanent magnets in the same manner as the correction of the temperature characteristics of the pair of Hall elements 101a and 101b.

Next, feedback control is performed so that the output signal of the summing amplifier 103 becomes constant in this way, and the output signal of the subtracting amplifier 103 is output as a position signal, so that it depends on the temperature characteristics of the pair of Hall elements 101a and 101b. The fact that the influence of the position detection error can be easily suppressed will be described. The output signals Vha and Vhb of the pair of Hall elements 101a and 101b when the ambient temperature is T and the magnet is at the predetermined position X can be expressed as the following equations (7) and (8).
Vha (T) = μ _H (T) × {B _Ma + B _Ca (T)} × Vcc (7)
Vhb (T) = μ _H (T) × {B _Mb + B _Cb (T)} × Vcc (8)

Here, B _Ma and B _Mb are magnetic flux densities of the permanent magnet 201 applied to the pair of Hall elements 101a and 101b. When Expressions (7) and (8) are developed in the same manner as in the first embodiment, the following is obtained.
ΔV (T) = {B _Ma + B _Ca (T) −B _Mb −B _Cb (T)}
/ {B _Ma + B _Ca (T) + B _Mb + B _Cb (T)} × Vref1 (9)

At this time, in the second embodiment, as described above, the intersection of the diagonal line D1 and the diagonal line D2 on the surface of the coil 107 facing the pair of Hall elements, and the diagonal line D3 and the diagonal line on the surface of the permanent magnet 202 facing the pair of Hall elements. Since the intersections of D4 are arranged so as to coincide with each other at C1, ΔV (T) is changed to {B _Ma + B _Ca (T) −B _Mb −B _Cb (T)}, {B _Ma + B _Ca (T) + B _Mb + B _Cb (T)}, and according to the second embodiment, as in the first embodiment, the coil is set so that the output signal of the summing amplifier 103 is constant. By controlling the value of the current flowing through 107, it is possible to easily suppress the position detection error due to the temperature characteristics of the pair of Hall elements.

  From the above, according to the second embodiment, the direction and magnitude of the current flowing in the coil 107 based on the magnetic field strength of the permanent magnet 202 is determined by the output signal (Vha) of the adding and amplifying means 103 by the output signal of the integrating means 104a. , Vhb multiplied by a gain) is constant so that the parameter for correcting the error due to the ambient temperature of the Hall element is obtained as in the first embodiment, and each device Therefore, the correction process can be easily performed without performing the correction operation according to the position, and the position can be detected with high accuracy. Furthermore, since the current supplied to the coil 107 only needs to generate a magnetic field that corrects the temperature characteristics of the Hall elements and the individual variations of the magnets, the current consumption of the position detection circuit can be reduced compared to the first embodiment.

  Next, Embodiment 3 of the present invention will be described. In the third embodiment, a case where the position detection circuit of the present invention is used for two-dimensional position detection will be described using a digital still camera having a shake correction function as an example of a specific usage form. FIG. 8 is a digital still camera using the position detection circuit of the present invention, and FIGS. 9 and 10 are a top view and a side view showing a shake correction apparatus in the digital still camera using the position detection circuit of the present invention. . First, the structure in Example 3 shown in each figure is demonstrated. A digital still camera according to the third embodiment shown in FIG. 8 includes a digital camera body 300, a power button 301, a shutter button 302, a photographing lens 303, an AF unit (not shown), an AE unit (not shown), a micro A computer 313a and a shake correction device 304 are provided. Supply and stop of power supply to the digital camera main body 300 are performed by turning on and off the power button 301, respectively. When the shutter button 302 is half-pressed, the AF unit and the AE unit are driven, and the AF unit and the AE unit perform the distance measuring operation and the photometric operation of the subject by using the incident light transmitted through the photographing lens 303. In the microcomputer 313a, shooting conditions such as a shutter speed and an aperture value at the time of shooting are calculated based on signals from the AF unit and the AE unit.

  9 and 10 show a top view and a side view of a shake correction device 304 that includes four Hall elements, in other words, a first pair of Hall elements 101a and 101b and a second pair of Hall elements 101c and 101d. A pair of Hall elements, two magnetic field generating means 308a and 308b, an imaging element 305, a movable part 306, a fixed part 307, a flexible substrate 309, a first Hall element signal processing circuit 100a, The second hall element signal processing circuit 100b, a gyro sensor 312 as a shake amount measuring means, and a movement control unit 313 are configured.

  The movable portion 306 is movably attached to the housing 300a of the main body 300, and includes an image sensor 305 and first and second magnetic field generating means 308a and 308b. The image sensor 305 is attached on the incident light side of the movable part so that the optical axis L of the incident light transmitted through the photographing lens 303 forms an image at the center of the imaging surface of the image sensor 305. Here, the center of the imaging surface is a point where two diagonal lines on the imaging surface intersect. The first and second magnetic field generating means 308a and 309b have the same configuration as that shown in the first or second embodiment in order to generate a magnetic field when performing position detection, and have a movable part. In 306, the first and second magnetic field generating means 308a and 309b are attached to the back surface of the surface on which the image pickup device 305 is attached so as to be located on the diagonal line of the movable part. . The movable unit 306 can be translated in the x-axis direction and the y-axis direction by driving a driving unit 313b such as a motor constituting the movement control unit 313.

  The fixing unit 307 is fixed to the casing 300a, and includes a pair of Hall elements (a first pair of Hall elements 101a and 101b and a second pair of Hall elements 101c and 101d), a first pair, and a second pair of Hall elements. Hall element signal processing circuits 100a and 100b and a gyro sensor 312 are provided. In the two pairs of Hall elements, the first pair of Hall elements 101a and 101b are discretely arranged in the x-axis direction, and the second pair of Hall elements 101c and 101d are discretely arranged in the y-axis direction. ing. Further, the first pair of Hall elements 101a and 101b and the first magnetic field generating means 308a are attached so as to face each other, and the second pair of Hall elements 101c and 101d and the second magnetic field generating means 308b are opposed to each other. Is attached.

  The first pair of Hall elements 101a and 101b obtains position information of the movable portion 306 in the x-axis direction. The first Hall element signal processing circuit 100a is attached in the vicinity of the flexible substrate 309 on the back side of the surface to which the two pairs of Hall elements are attached, and the first pair of Hall elements in the fixing portion 307. 101a, 101b and the first Hall element signal processing circuit 100a are connected to form an X-axis position detection circuit 310. The second pair of Hall elements 101c and 101d obtains position information of the movable portion 306 in the y-axis direction. The second Hall element signal processing circuit 100b is attached in the vicinity of the flexible substrate 309 and the Hall element signal processing circuit 100a on the back side of the surface on which the two pairs of Hall elements are attached. The second pair of Hall elements 101c and 101d and the second Hall element signal processing circuit 100b are connected to form a Y-axis position detection circuit 311.

  The gyro sensor 312 is mounted on the same surface as the first and second hall element signal processing circuits 100a and 100b, and the output signals of the gyro sensor 312 and the hall element signal processing circuits 100a and 100b constitute a movement control unit 313. Connected to the microcomputer 313a. The movable unit 306 and the fixed unit 307 are connected by a flexible substrate 309, and the image sensor 305 can transmit and receive signals to and from a circuit (not shown) that processes the output signal of the image sensor 305 disposed on the fixed unit 307. Yes. The first Hall element signal processing circuit 100a and the first magnetic field generating means 308a, and the second Hall element signal processing circuit 100b and the second magnetic field generating means 308b are connected by the flexible substrate 309, respectively, so that the first hall Current can be supplied from the element signal processing circuit 100a to the first magnetic field generation means 308a and from the second Hall element signal processing circuit 100b to the second magnetic field generation means 308b.

  Next, the operation of the shake correction apparatus configured as described above will be described. When vibration is generated (blurred) in the digital camera body 300, the shake correction device 304 in the digital camera body 300 also vibrates in the same manner. Then, the angular velocity around the x-axis and y-axis of the vibration generated by the gyro sensor 312 in the shake correction device 304 is detected and an angular velocity signal is output to the microcomputer 313a. At this time, the X-axis position detection circuit 310 and the Y-axis position detection circuit 311 obtain the x-axis position information and the y-axis position information of the movable portion 306 (imaging element 305) and output them to the microcomputer 313a.

  The microcomputer 313a calculates the moving amount (blur amount) and moving speed (blur velocity) of the image on the image sensor 305 due to the blur of the digital camera body 300 from the angular velocity signal of the gyro sensor 312. Then, using the calculated shake amount and the current position information of the movable portion 306 (imaging device 305), the movable portion 306 (imaging device) is moved at a speed that follows the shake speed in the direction in which the generated shake amount is suppressed. 305) is moved (corrected), the voltage to be applied to the driving means 313b such as a motor is determined. That is, the microcomputer 313a detects the current position information of the movable unit 306 (imaging device 305) input from the X-axis position detection circuit 310 and the Y-axis position detection circuit 311 and the movable unit 306 ( The position where the image pickup device 305) is to be corrected is compared, and feedback control is performed so that the movable portion 306 (image pickup device 305) moves to the position to be corrected.

  For example, when a shake correction operation is performed and the position of the image sensor 305 is detected by the X-axis position detection circuit 310 and the Y-axis position detection circuit 311, the position of the image sensor 305 is excessive with respect to the position to be corrected. Based on the output signals of the X-axis position detection circuit 310 and the Y-axis position detection circuit 311, the moving amount of the image sensor 305 is adjusted to return to the position to be corrected, and the image sensor 305 is moved to the position to be corrected. Similarly, when the position of the image pickup device 305 is detected by the X-axis position detection circuit 310 and the Y-axis position detection circuit 311, the movement of the image pickup device 305 is too small relative to the position to be corrected. Based on the outputs of the detection circuit 310 and the Y-axis position detection circuit 311, the movement amount of the image sensor 305 is adjusted in a direction approaching the position to be corrected, and the image sensor 305 is moved to the position to be corrected.

  Therefore, the shake correction apparatus having such a configuration is similar to the first and second embodiments described above in accordance with an operation for obtaining a parameter for correcting a position detection error due to the temperature characteristic of the Hall element, or according to each apparatus. The position of the movable part (imaging device) can be detected with high accuracy without performing the correction operation, and shake correction can be easily performed with high accuracy. In this embodiment, the image pickup device 305 is moved together with the movable unit 306 to perform blur correction. However, the image pickup device 305 is fixed and a part of the lens group constituting the photographing lens 303 is fixed. The motion compensation operation may be performed by moving the lens in the x-axis direction and the y-axis direction.

  In this embodiment, a digital still camera that captures a still image has been described as an example. However, the same effect can be obtained when the present invention is applied to an imaging device (video camera or digital video camera) that captures a moving image. . In the present embodiment, two pairs of Hall elements are arranged in the fixed portion 307, and the first and second magnetic field generating means 308a and 308b are arranged in the movable portion 306. The pair of Hall elements and the first and second magnetic field generating means 308a and 308b may be interchanged. That is, the same effect can be obtained by arranging the two pairs of Hall elements in the movable portion 306 and the first and second magnetic field generating means 308a and 308b in the fixed portion 307.

  In each embodiment, the configuration using a rectangular coil as the magnetic field generating means is shown. However, the magnetic field generating means used in the present invention is not limited to the rectangular coil, and the same effect can be obtained as a circular coil. . Moreover, although the thing using the Hall element was shown as a magnetic field change detection element, the magnetic field change detection element used for this invention is not restricted to a Hall element. Specifically, the same effect can be obtained by using an element capable of obtaining positional information such as a movable substrate by detecting a change in a magnetic field, such as an MI sensor, a magnetic resonance type magnetic field detection element, or an MR element. It is done.

It is a block diagram which shows the structure of Example 1 of the position detection circuit based on this invention. It is a perspective view which shows the physical arrangement | positioning of the component used for the position detection in Example 1 shown in FIG. It is a top view which shows the physical arrangement | positioning of the component similarly used for a position detection. 6 is a block diagram illustrating a configuration of Example 2. FIG. It is a front view which shows the physical arrangement | positioning of the component used for the position detection in Example 2 shown in FIG. It is a perspective view which shows the physical arrangement | positioning of the component similarly used for a position detection. It is a top view which shows the physical arrangement | positioning of the component similarly used for a position detection. It is a perspective view which shows the digital still camera which concerns on Example 3 using the position detection circuit which concerns on this invention. It is a top view which shows the structure of the blurring correction apparatus in the digital still camera shown in FIG. It is a side view which similarly shows the structure of a shake correction apparatus.

Explanation of symbols

100 Hall element signal processing circuit
101a, 101b Hall element (magnetic field change detection element)
102 Subtraction amplification means
103 Addition amplification means
104 Control value generation means
104a Integration means
104b Reference voltage
105 VI conversion means
106 Magnetic field generation means
107 rectangular coil
201 Magnetic field generation means
202 Permanent magnet
300 Digital camera body
300a enclosure
301 Power button
302 Shutter button
303 Photo lens
304 Image stabilizer
305 Image sensor
306 Moving parts
307 Fixed part
308a First magnetic field generating means
308b Second magnetic field generating means
309 Flexible substrate
310 X-axis position detection circuit
311 Y-axis position detection circuit
312 Gyro sensor
313 Movement control unit
313a microcomputer
313b Driving means

Claims (5)

A plurality of magnetic field change detecting elements arranged at a predetermined interval;
Magnetic field generating means for generating a magnetic field according to the input current;
Subtracting means for subtracting each output from the plurality of magnetic field change detection elements,
A position detection circuit for detecting a relative positional relationship between the plurality of magnetic field change detection elements and the magnetic field generation means based on a subtraction result of the subtraction means;
Adding means for adding outputs from the plurality of magnetic field change detecting elements;
Control value generating means for generating a control value for suppressing a difference between a reference value and the addition result of the adding means;
A position detecting circuit comprising: a converting means for converting the control value of the control value generating means into a current and outputting the current as an input current of the magnetic field generating means.   The position detection circuit according to claim 1, wherein the magnetic field generation means is a coil.   The position detection circuit according to claim 1, wherein the magnetic field generation unit includes a coil and a permanent magnet.   The coil and the permanent magnet have a rectangular shape, and the arrangement relationship thereof is that the coil is disposed on the outer periphery of the permanent magnet, and the coil and the permanent magnet are arranged on the surface facing the magnetic field change detection element. The position detection circuit according to claim 3, wherein a point where two diagonal lines of the two intersect and a point where two diagonal lines of the permanent magnet intersect with each other. A movable holding unit that holds the photographic lens or an image sensor that converts an image of a subject incident through the photographic lens into an electrical signal, movably with respect to the housing of the imaging device;
A magnetic field generating means attached to either the movable holding part or the member fixed to the casing and generating a magnetic field;
The position detection circuit according to any one of claims 1 to 4, which is disposed on the other side surface of the movable holding portion or a member fixed to the housing, facing the magnetic field generation means, A shake amount measuring means for measuring a shake amount of the housing;
An imaging apparatus comprising: a movement control unit that moves the movable holding unit so as to cancel out the amount of blur based on an output from the position detection circuit.

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