Actuator driver, camera module, and electronic apparatus

Abstract

The invention provides an actuator driver capable of suppressing degradation of image quality. The first actuator (142 - 1) and the second actuator (142 - 2) position the lens (132) in the Z-axis direction. The feedback controller (330) includes a correction circuit (350), and generates a first control code (CTRLZ1) and a second control code (CTRLZ2) such that the optical axis of the lens (132) remains parallel to the Z-axis direction regardless of the value of a target code (ZREF) indicating the target position of the lens (132) in the Z-axis direction, and outputs the first control code (CTRLZ1) and the second control code (CTRLZ2) to the correction circuit (350). The correction circuit (350) holds a parameter determined on the basis of a mismatch between the distance per 1LSB (Least Significant Bit) of a first position detection code (ZDET1) indicating the amount of displacement of the first actuator (142 - 1) and the distance per 1LSB of a second position detection code (ZDET2) indicating the amount of displacement of the second actuator (142 - 2).

Description

Technical Field

[0001] The present disclosure relates to an actuator driver. Background Art

[0002] In recent years, camera modules have been installed in various electronic devices such as smartphones. The performance of camera modules is important in improving the added value of electronic devices.

[0003] It is difficult to incorporate a telephoto lens in a thin housing of a smartphone or the like. Therefore, in order to obtain a longer optical path length, a periscope-type camera module using a prism has been proposed.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] Patent Document 1: U.S. Patent Application Publication No. 2023 / 0038826 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] The present inventors have studied optical hand shake correction in a periscope-type camera module and have found the following problems.

[0009] In a periscope camera module, the position of an image formed on an image sensor can be shifted by rotating a prism, and hand shake can be corrected. Hand shake correction is generally performed in two-axis directions. The present inventors have studied the following case: among the hand shake corrections in the two axes, corrections in one axis are performed by a prism, and corrections in the other axis are performed by an AF (auto focus) lens.

[0010] In this case, the actuator system of the AF lens is positioned in the optical axis direction (called the Z axis direction) for autofocus, and further in the 1-axis direction perpendicular to the optical axis (called the X axis direction) for hand shake correction. In this case, when the AF lens is displaced in the Z axis direction, if the AF lens rotates around the Y axis, the optical axis of the AF lens will not be parallel to the Z axis, and the image formed on the image sensor will be distorted, and the image quality will deteriorate.

[0011] The present disclosure has been made in view of the above-mentioned problems, and one of its exemplary purposes is to provide an actuator driver that can suppress degradation of image quality.

[0012] [Technical solutions for solving technical problems]

[0013] One scheme of the present disclosure relates to an actuator driver that drives a first actuator and a second actuator that are separately arranged along the X-axis direction and respectively position a lens in the Z-axis direction perpendicular to an image sensor. The actuator driver includes: a first position detection circuit that generates a first position detection code indicating the displacement of the first actuator; a second position detection circuit that generates a second position detection code indicating the displacement of the second actuator; a first drive circuit that drives the first actuator according to a first control code; a second drive circuit that drives the second actuator according to a second control code; and a feedback controller that generates a first control code and a second control code through feedback control based on a target code indicating a target position of the lens in the Z-axis direction, the first position detection code, and the second position detection code. The feedback controller includes a correction circuit and generates a first control code and a second control code in a manner that is independent of the value of the target code and that maintains the optical axis of the lens parallel to the Z-axis direction. The correction circuit maintains parameters determined based on a mismatch between the distance per 1LSB (Least Significant Bit) of the first position detection code and the distance per 1LSB of the second position detection code.

[0014] In addition, any combination of the above constituent elements, and the result of replacing constituent elements or expressions between methods, devices, systems, etc., are also valid as the present invention or the scheme disclosed herein. Furthermore, the record of this item (means for solving the problem) does not describe all the indispensable features of the present invention, and therefore, a sub-combination of these recorded features can also constitute the present invention.

[0015] Effects of the Invention

[0016] According to the present disclosure, image quality can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The diagram shows an electronic device with a camera function.

[0018] Figure 2 It is a diagram showing a camera module.

[0019] Figure 3 yes Figure 2 A block diagram of an actuator driver and an actuator for a lens.

[0020] Figure 4 This is a diagram for explaining the positioning of the lens in the Z-axis direction by the lens actuator in an ideal state.

[0021] Figure 5 It is a diagram for explaining the positioning of the lens in the Z-axis direction by the lens actuator in a real state.

[0022] Figure 6 Yes means Figure 5 A diagram showing the relationship between the target code and the rotation angle of the lens in the state.

[0023] Figure 7 is a block diagram of the feedback controller of Example 1.

[0024] Figure 8 This is a diagram showing the relationship between the target code measured in the calibration process and the rotation angle of the lens.

[0025] Fig. 9 FIG. 1 is a diagram showing a position detection code before correction and a position detection code after correction.

[0026] Fig.10 It is a block diagram of the feedback controller of Example 2.

[0027] Fig.11 It is a block diagram of the feedback controller of Example 3.

[0028] Fig.12 This is an exploded perspective view of a lens actuator of a comparative technology.

[0029] Fig.13 This is an exploded perspective view of a lens actuator suitable for an actuator driver. DETAILED DESCRIPTION

[0030] (Overview of Embodiments)

[0031] Below, an overview of several exemplary embodiments of the present disclosure is described. This overview is a prelude to the detailed description described later, and is intended to simplify and explain several concepts in one or more embodiments for the purpose of basic understanding of the embodiments, and does not limit the breadth of the invention or disclosure. This overview is not a comprehensive overview of all conceivable embodiments, nor is it intended to determine the important elements of all embodiments or to divide the scope of a part or all of the schemes. For convenience, "one embodiment" is sometimes used to refer to one embodiment (embodiment or variation) or multiple embodiments (embodiment or variation) disclosed in this specification.

[0032] An actuator driver in one embodiment is an actuator driver that is separately configured along the X-axis direction and drives a first actuator and a second actuator that respectively position a lens in a Z-axis direction perpendicular to an image sensor, and includes: a first position detection circuit that generates a first position detection code representing the displacement amount of the first actuator; a second position detection circuit that generates a second position detection code representing the displacement amount of the second actuator; a first drive circuit that drives the first actuator according to a first control code; a second drive circuit that drives the second actuator according to a second control code; and a feedback controller that generates a first control code and a second control code through feedback control based on a target code representing a target position of the lens in the Z-axis direction, the first position detection code, and the second position detection code. The feedback controller includes a correction circuit and generates a first control code and a second control code in a manner that is independent of the value of the target code and that maintains the optical axis of the lens parallel to the Z-axis direction. The correction circuit maintains parameters determined based on the mismatch between the distance per 1LSB (Least Significant Bit) of the first position detection code and the distance per 1LSB of the second position detection code.

[0033] In the conventional feedback control, when the relationship between the actual displacement of the first actuator and the first position detection code and the relationship between the actual displacement of the second actuator and the second position detection code are different, that is, when the displacement corresponding to 1LSB of the code is different in the first position detection circuit and the second position detection circuit, when the target code is changed, the lens will perform translational motion along the Z axis while rotating around the Y axis, and the image quality will deteriorate. According to the configuration of one embodiment, the rotation of the lens caused by the error between the first position detection circuit and the second position detection circuit can be suppressed by pre-programming a parameter (correction characteristic) into the feedback controller, thereby improving the image quality. The parameter is determined in a manner that the optical axis of the lens is maintained parallel to the Z axis direction regardless of the value of the target code.

[0034] Alternatively, in one embodiment, the correction circuit is configured to correct the first position detection code and the second position detection code based on a parameter. Alternatively, the feedback controller generates the first control code in a manner that the corrected first position detection code approaches the first target code based on the target code representing the target position in the Z-axis direction of the lens, and generates the second control code in a manner that the corrected second position detection code approaches the second target code based on the target code. In this configuration, the correction circuit can be used to make the displacement ΔZ of the first actuator equivalent to 1LSB of the corrected first position detection code 1 ' and the displacement ΔZ of the second actuator corresponding to 1LSB of the corrected second position detection code 2'consistent and able to suppress the rotation of the lens.

[0035] Alternatively, in one embodiment, the parameters include a first gain, a second gain, a first bias, and a second bias. Alternatively, the correction circuit uses a value obtained by adding the first bias to a value obtained by multiplying the first position detection code by the first gain as the first position detection code after correction, and uses a value obtained by adding the second bias to a value obtained by multiplying the second position detection code by the second gain as the second position detection code after correction. In this case, by optimizing the first gain and the second gain, the rotation can be suppressed, and by optimizing the first bias and the second bias, the inclination angle of the lens can be set to 0°.

[0036] Alternatively, in one embodiment, the correction circuit corrects the target code representing the target position of the lens in the Z-axis direction based on the parameter to generate the first target code, and corrects the target code based on the parameter to generate the second target code. Alternatively, the feedback controller generates the first control code in a manner that the first position detection code is close to the first target code, and generates the second control code in a manner that the second position detection code is close to the second target code. REF The first target code Z for each 1LSB REF1 The change in REF1 , the second target code Z REF2 The change in REF2 to meet

[0037] ΔZ REF2 / ΔZ REF1 =ΔZ 1 / ΔZ 2 The parameters are determined in a manner such that the rotation of the lens can be suppressed.

[0038] Alternatively, in one embodiment, the parameters include a first gain, a second gain, a first bias, and a second bias. Alternatively, the correction circuit uses a value obtained by adding the first bias to a value obtained by multiplying the target code by the first gain as the first target code, and uses a value obtained by adding the second bias to a value obtained by multiplying the target code by the second gain as the second target code. In this case, by optimizing the first gain and the second gain, rotation can be suppressed, and by optimizing the first bias and the second bias, the inclination of the lens can be set to 0°.

[0039] Alternatively, in one embodiment, the correction circuit generates a rotation angle correction code corresponding to the target code based on the parameter. Alternatively, the feedback controller includes: a coordinate conversion circuit that generates a translation position detection code and a rotation angle detection code, the translation position detection code indicating the translation position of the lens in the Z-axis direction based on the first position detection code and the second position detection code, and the rotation angle detection code indicating the rotation angle of the lens around the Y-axis perpendicular to the X-axis direction and the Z-axis direction; and an operation circuit that generates the first control code and the second control code in such a way that the error between the target code and the translation position detection code approaches zero, and in such a way that the error between the rotation angle correction code and the rotation angle detection code approaches zero. According to this configuration, the rotational motion of the lens can be suppressed by converting into two coordinate systems, namely the translational motion and the rotational motion, and appropriately determining the rotation angle correction code as the command value of the rotational motion.

[0040] In one embodiment, the parameter may be determined in the calibration step based on the relationship between the target code and the rotation angle of the lens when the target code is changed.

[0041] Alternatively, in one embodiment, the rotation angle of the lens is determined by an autocollimator.

[0042] Alternatively, in one embodiment, the rotation angle of the lens is calculated by passing an object through the lens and based on an image captured by an image sensor.

[0043] Alternatively, a camera module in one embodiment includes: a lens supported so as to be movably supported in an XZ plane; a first actuator and a second actuator configured to separately clamp the lens along the X-axis direction and respectively position the lens in the Z-axis direction corresponding to the optical axis direction; an actuator driver that drives the first actuator and the second actuator based on a target code; and an image sensor that captures an image passing through the lens.

[0044] The camera module according to one embodiment may further include a third actuator for positioning the lens in the X-axis direction. The actuator driver may be capable of controlling the third actuator.

[0045] The camera module according to one embodiment may further include a prism that bends the image of the subject toward the lens, and may be of a periscope type.

[0046] An electronic device according to an embodiment may include a camera module.

[0047] (Implementation Method)

[0048] The following describes a preferred embodiment with reference to the accompanying drawings. The same or equivalent components, members, and processes shown in the drawings are marked with the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the embodiments do not limit the disclosure and invention, but are only examples. Not all features and combinations described in the embodiments are the substantive contents of the disclosure and invention.

[0049] In this specification, the so-called "the state in which component A and component B are connected" includes not only the case in which component A and component B are directly physically connected, but also the case in which component A and component B are indirectly connected via other components that do not substantially affect their electrical connection state or do not impair the function or effect of their combination.

[0050] Similarly, the so-called "state in which component C is arranged between component A and component B" includes, in addition to the situation in which component A and component C, or component B and component C are directly connected, also includes the situation in which they are indirectly connected via other components that do not have a substantial impact on their electrical connection state or do not damage the function or effect achieved by their combination.

[0051] Figure 1 2 is a diagram showing an electronic device 200 with a camera function. The electronic device 200 includes a periscope-type camera module 100 and an image processor 210. The electronic device 200 is not particularly limited, but examples thereof include a smartphone, a tablet terminal, and a laptop computer.

[0052] The camera module 100 includes an image sensor 110 , a prism 120 , and an imaging optical system 130 .

[0053] The prism 120 bends the light L1 from the subject toward the image sensor 110. The imaging optical system 130 forms an image of the light L2 bent by the prism 120 on the imaging surface of the image sensor 110. Some lenses of the imaging optical system 130 may be disposed on the path of the light L1.

[0054] The image IMG1 captured by the image sensor 110 is supplied to the image processor 210. The image processor 210 processes the image IMG1 and displays it on a display (not shown) or stores it in a memory (not shown).

[0055] The Z-axis direction is perpendicular to the imaging surface of the image sensor 110 , and the X-axis direction and the Y-axis direction are perpendicular to the Z-axis direction. The Y-axis direction is parallel to the light L1 emitted from the subject to the prism 120 .

[0056] The camera module 100 has an autofocus function. The imaging optical system 130 includes a lens 132 for autofocus, and focusing is performed by displacing the lens 132 in the Z-axis direction.

[0057] In addition, the camera module 100 has a hand shake correction function. The hand shake to be corrected is the rotation (pitch) around the Z axis and the rotation (yaw) around the X axis. The lens 132 for autofocus also serves as a lens for hand shake correction. The camera module 100 positions the lens 132 in the X direction to eliminate the rotational motion (pitch) of the electronic device 200 around the Z axis.

[0058] In the present disclosure, the correction method of the rotation (yaw) around the X-axis is not particularly limited, but for example, hand shake can be corrected by rotating the prism 120 around the X-axis.

[0059] Figure 2 1 is a diagram showing a camera module 100 . The camera module 100 has an auto focus function and an optical hand shake correction function. The camera module 100 includes an image sensor 110 , a prism 120 , a lens 132 , a lens actuator 140 , a prism actuator 150 , and a gyro sensor 160 .

[0060] The angular velocity ω of the rotation around the Z axis by the gyro sensor 160 P , and the angular velocity ω of the rotation around the X axis Y Conduct testing.

[0061] The position of the lens 132 in the Y-axis direction is restricted, and the lens 132 is supported to be freely movable in the X-axis direction and the Z-axis direction. For pitch hand shake correction, the lens actuator 140 is configured to position the lens 132 in the X-axis direction. In addition, for autofocus, the lens actuator 140 is configured to position the lens 132 in the Z-axis direction.

[0062] The prism 120 is supported so as to be rotatable around the X-axis. The prism actuator 150 is configured to rotate the prism 120 in the X-axis direction for yaw camera shake correction.

[0063] The actuator driver 300 generates an angular velocity ω based on the angular velocity ω from the gyro sensor 160. P , controls the lens actuator 140, and controls the position of the lens 132 in the X-axis direction. In addition, the actuator driver 300 receives a control signal SAF for autofocus from a processor not shown, and controls the lens actuator 140 based on the control signal SAF, and controls the position of the lens 132 in the Z-axis direction.

[0064] Furthermore, the actuator driver 300 generates an angular velocity ω based on the angular velocity ω from the gyro sensor 160. Y, controls the prism actuator 150 and controls the rotation angle of the prism 120 around the X-axis.

[0065] Figure 3 yes Figure 2 The actuator driver 300 and the lens actuator 140 are block diagrams. The actuator driver 300 is an IC integrated into a semiconductor substrate (chip), and is also called an actuator driver IC. Figure 2 In FIG. 1 , only the portion related to the lens actuator 140 is shown, and the portion related to the prism actuator 150 is omitted.

[0066] Regarding the positioning of the Z axis, the lens actuator 140 includes a first actuator 142_1, a second actuator 142_2, a first position detection element 144_1, and a second position detection element 144_2. The first actuator 142_1 and the second actuator 142_2 are configured to be separated along the X axis direction. The first actuator 142_1 positions the lens 132 in the Z axis direction on the first side in the X axis direction, and the second actuator 142_2 positions the lens 132 in the Z axis direction on the second side in the X axis direction. Specifically, the movable portion of the first actuator 142_1 is connected to the first position of the lens 132, and the movable portion of the second actuator 142_2 is connected to the second position, which is separated from the first position of the lens 132 in the X axis direction.

[0067] The first position detection element 144_1 is paired with the first actuator 142_1 to generate a first position detection signal Z1, which indicates the position of the movable element of the first actuator 142_1 in the Z-axis direction. Similarly, the second position detection element 144_2 is paired with the second actuator 142_2 to generate a second position detection signal Z2, which indicates the position of the movable element of the second actuator 142_2 in the Z-axis direction. Hall sensors or the like can be used as the position detection elements 144_1 and 144_2. The position detection signals Z1 and Z2 are input to the position detection pins DETZ1 and DETZ2 of the actuator driver 300.

[0068] Regarding the positioning in the X-axis direction, the lens actuator 140 includes an actuator 146 and a position detection element 148. The actuator 146 positions the lens 132 in the X-axis direction.

[0069] The position detection element 148 is paired with the actuator 146 to generate a position detection signal X indicating the position of the movable element of the actuator 146 in the X-axis direction. A Hall sensor or the like can be used as the position detection element 148. The position detection signal X is input to a position detection pin DETX of the actuator driver 300.

[0070] The actuator driver 300 includes a calculation processing unit 310 , a Z-axis control system 320 , and an X-axis control system 360 .

[0071] The calculation processing unit 310 calculates the pitch angular velocity ω based on the pitch angular velocity ω. P , generate target code X REF , the target code X REF represents the target position of the lens 312 in the X direction. For example, the processing unit 310 calculates the angular velocity ω P Integrate and convert it into angle information θ P , and based on the angle information θ P To generate the target code X REF The control system 360 approaches the target code X with the position detection signal X REF The drive signal (drive current) I is generated by feedback DRVX , and supplies it to the actuator 146. The configuration of the control system 360 is not particularly limited, and a known technique can be used.

[0072] For example, the control system 360 includes a position detection circuit 362, a drive circuit 364, and a feedback controller 366. The position detection circuit 362 generates a position detection code XDET, which indicates the position of the movable element of the actuator 146. For example, the position detection circuit 362 may include an A / D converter, which converts the output of the position detection element 148 into a digital code.

[0073] The feedback controller 366 generates the control code CTRLX in such a way that the position detection code XDET approaches the target code XREF, that is, in such a way that the error between them approaches zero. The feedback controller 366 can include a PID (proportional, integral, derivative) compensator that takes the error as an input.

[0074] The driving circuit 364 generates a driving signal (driving current) I corresponding to the control code CTRLX. DRVX .

[0075] Next, the Z-axis control system 320 will be described. The position of the lens 132 in the Z direction is controlled by the lens actuators 142_1 and 142_2.

[0076] The calculation processing unit 310 receives a position instruction of the lens 132 from a processor (not shown) that is responsible for autofocus control, and generates a target code Z based on the position instruction. REF , the target code Z REF Indicates the target position of the lens 132 in the Z-axis direction.

[0077] The Z-axis control system 320 includes a first position detection circuit 322_1 , a second position detection circuit 322_2 , a first drive circuit 324_1 , a second drive circuit 324_2 , and a feedback controller 330 .

[0078] The first position detection circuit 322_1 generates a first position detection code Z DET1 , the first position detection code Z DET1 The second position detection circuit 322_2 generates a second position detection code Z DET2 , the second position detection code Z DET2 Indicates the displacement of the movable element of the second actuator 142_2 in the Z direction. The first position detection circuit 322_1 and the second position detection circuit 322_2 may each include an A / D converter that converts the output of the first position detection element 144_1 and the second position detection element 144_2 into a digital signal.

[0079] The first driving circuit 324_1 generates a first control code CTRLZ according to the feedback controller 330. 1 To generate the drive current I DRVZ1 , and supplies it to the first actuator 142_1. Similarly, the second drive circuit 324_2 generates a second control code CTRLZ according to the feedback controller 330. 2 To generate the drive current I DRVZ2 and supplies it to the second actuator 142_2.

[0080] The feedback controller 330 generates a signal based on a target code Z indicating a target position of the lens 132 in the Z-axis direction. REF , 1st position detection code Z DET1 , 2nd position detection code Z DET2 , through feedback control, generate the first control code CTRLZ 1 And the second control code CTRLZ 2 .

[0081] The feedback controller 330 has a REF The feedback controller 330 generates a first control code CTRLZ based on the correction characteristic. 1 And the second control code CTRLZ 2 .

[0082] Explain why correction is needed. Figure 4 1 is a diagram for explaining the positioning of the lens 132 in the Z-axis direction by the lens actuator 140 in an ideal state. Figure 4 The first position detection code Z is shown in DET1 The value of and the positional relationship between the movable element M1 and the second position detection code Z DET2 Here, for easy understanding, the first position detection code Z DET1 and the second position detection code Z DET2 Take -4 to +4.

[0083] In an ideal situation, the two position detection codes Z DET1 , Z DET2 The distance ΔZ relative to 1LSB 1 , ΔZ 2 The same, in all values, shows the same Z-axis position. REF1 =Z REF2 =Z REF , with Z DET1 =Z REF1 Feedback control is applied in the form of Z DET2 =Z REF2 By applying feedback control in a manner, the optical axis of the lens 132 can be maintained parallel to the Z-axis direction. In other words, the surface of the lens 132 is ensured to be parallel to the imaging surface of the image sensor for positioning.

[0084] Figure 5 1 is a diagram for explaining the positioning of the lens 132 in the Z-axis direction by the lens actuator 140 in the actual state. DET1 The distance ΔZ equivalent to 1LSB 1 With the second position detection code Z DET2 The distance ΔZ equivalent to 1LSB 2 Different (ΔZ 1 >ΔZ 2 ).exist Figure 5 In the figure, Z REF =The position and posture of the lens 132 in the three states of -3, 1, and 4.

[0085] Figure 6 Yes means Figure 5 The target code Z in the state REF The rotation angle of the lens 132 Rotation angle When the lens 132 is parallel to the X-axis, 0 degrees is taken, and the clockwise direction is taken as positive.

[0086] In ΔZ 1 ≠ΔZ 2 In the case of REFWhen the lens 132 changes, the lens 132 performs translational movement in the Z-axis direction while performing rotational movement around the Y-axis. The rotation of the lens 132 around the Y-axis may cause degradation of the image captured by the image sensor 110.

[0087] The above is the reason why calibration is required when positioning is performed using the two actuators 142_1 and 142_2 in the Z-axis direction.

[0088] Back to Figure 3 The feedback controller 330 includes a correction circuit 350. The correction circuit 350 maintains the first position detection code Z DET1 The distance ΔZ per 1LSB 1 With the second position detection code Z DET2 The distance ΔZ per 1LSB 2 The feedback controller 330 uses this parameter to generate the first control code CTRLZ 1 And the second control code CTRLZ 2 , which can be combined with the target code Z REF Regardless of the value of , the lens 132 is positioned in the Z-axis direction while maintaining the optical axis of the lens 132 parallel to the Z-axis direction.

[0089] The parameters are determined in the calibration process. The process of the calibration process can be determined according to the configuration of the feedback controller 330. In addition, the calibration can be performed for each individual camera module 100 or for each manufacturing batch of the camera module 100. In addition, it is also possible to retain multiple parameter sets in one actuator driver 300 in advance, and to enable the parameter set to be dynamically selected according to the operating environment (temperature or power supply voltage, etc.).

[0090] ΔZ 1 With ΔZ 2 The size relationship will give Figure 6 The slope of the graph. ΔZ 1 =ΔZ 2 When ΔZ is the ideal state, the slope of the graph is 0. 1 >ΔZ 2 When Figure 6 In that case, it increases to the right, and the slope of the graph is positive. 1 <ΔZ 2 When , the graph decreases to the right and the slope of the graph is negative.

[0091] The above is the configuration of the actuator driver 300. According to the actuator driver 300, the optical axis of the lens 132 can be positioned in the Z-axis direction while being kept parallel to the Z-axis direction.

[0092] The technology disclosed in this disclosure can be understood as Figure 3The block diagram or circuit diagram of the present invention or various devices and methods derived from the above description are not limited to a specific configuration. The following is not intended to narrow the scope of the present disclosure, but to facilitate the understanding of the essence or operation of the present disclosure or the present invention and to clarify them. More specific configuration examples and embodiments are described.

[0093] (Example 1)

[0094] Figure 7 FIG. 1 is a block diagram of a feedback controller 330A according to Embodiment 1. In Embodiment 1, a correction circuit 350A corrects the first position detection code Z based on the parameters. DET1 and the second position detection code Z DET2 The feedback controller 330A generates the first control code CTRLZ in the following manner: 1 : Corrected first position detection code Z DET1 'Close to the target code Z REF The first target code Z REF1 , the target code Z REF represents the target position of the lens 132 in the Z-axis direction. Similarly, the feedback controller 330A generates the second control code CTRLZ as follows: 2 : Corrected second position detection code Z DET2 Close to target code Z REF The second target code Z REF2 In this embodiment, Z REF1 =Z REF2 .

[0095] The parameters include the first gain G 1 , the second gain G 2 , 1st bias OFS 1 , 2nd bias OFS 2 The correction circuit 350A is used to detect the first position code Z DET1 Multiply by the first gain G 1 Add the first offset OFS to the obtained value 1 The value Z DET1 ×G 1 +OFS 1 As the first position detection code Z after correction DET1 '.

[0096] Z DET1 '=Z DET1 ×G 1 +OFS 1

[0097] Similarly, the correction circuit 350A is to set the second position detection code Z DET2 Multiply by the second gain G2 Add the second offset OFS to the obtained value 2 The value Z DET2 ×G 2 +OFS 2 As the corrected second position detection code Z DET2 '.

[0098] Z DET2 '=Z DET2 ×G 2 +OFS 2

[0099] In addition to the correction circuit 350A, the feedback controller 330A includes error detectors 332_1 and 332_2 and PID compensators 334_1 and 334_2.

[0100] The error detector 332_i is a subtractor (adder) that generates Z REFi With Z DETi 'The error err i .

[0101] err i =Z REFi -Z DETi

[0102] PID compensator 334_i receives error err i , generate control code CTRLZ i .

[0103] CTRLZ i =K P ·err i +K I ∫err i dt+K D ·derr i / dt

[0104] The correction circuit 350A includes multipliers 351_1, 351_2 and adders 352_1, 352_2. The multiplier 351_i (i=1, 2) converts the position detection code Z DETi Multiply by the gain G i The adder 352_i adds the offset OFS to the output of the multiplier 351_i. i .

[0105] Alternatively, the feedback controller 330A may also be Figure 7 Alternatively, the feedback controller 330A may be implemented as a combination of a processor and a software program.

[0106] Next, the calibration process in Example 1 is described.

[0107] In the calibration process, the target code Z in the actuator driver 300 is adjusted without reflecting the correction characteristics based on the parameters. REF Scan. For the target code Z at this time REF The rotation angle of the lens 312 relationship is determined.

[0108] Figure 8 is the target code Z measured in the calibration process REF The rotation angle of the lens 312 If we plot the target code Z REF With rotation angle The relationship between the rotation angle and the rotation angle is shown in Figure A. Alternatively, in the calibration process, the reference image may be captured by the camera module 100, and the rotation angle may be calculated based on the relationship between the image captured by the image sensor 110 and the reference image.

[0109] The slope of graph A is based on the position detection code Z DET1 , Z DET2 The distance ΔZ per 1LSB 1 , ΔZ 2 To determine. ΔZ 1 =ΔZ 2 When , the slope of graph A is 0, and ΔZ 1 ≠ΔZ 2 , graph A will have a slope. Specifically, ΔZ 1 >ΔZ 2 When , the slope of Figure A is positive (rising to the right), and the magnitude of the inclination is related to ΔZ 1 and ΔZ 2 The ratio ΔZ 1 / ΔZ 2 There is a positive correlation. That is, ΔZ 1 / ΔZ 2 The larger the value, the steeper the inclination. 1 <ΔZ 2 When , the slope of Figure A is negative (declining to the right), and the magnitude of the slope is related to ΔZ 1 and ΔZ 2 The ratio ΔZ 2 / ΔZ 1 There is a positive correlation.

[0110] The corrected Z DET1 'The distance from 1LSB is denoted as ΔZ 1 ', the corrected Z DET2'The distance from 1LSB is denoted as ΔZ 2 '. Based on the slope of Figure A, we can use ΔZ 1 '=ΔZ 2 ' method to determine the gains G1 and G2. Figure 8 Graph B shows the target code Z when the gains G1 and G2 are reflected. REF With rotation angle In this state, the lens 132 is oriented at an offset angle of 1 to 10 with respect to the Z-axis direction. Perform translational movement while tilting.

[0111] The offset angle Can be biased by OFS 1 OFS 2 By adjusting to zero, Figure C can be obtained.

[0112] Fig. 9 It indicates the position detection code Z before correction DET1 , Z DET2 , and the corrected position detection code Z DET1 ', Z DET2 By multiplying the gains G1 and G2, the distance ΔZ per 1LSB 1 ' and ΔZ 2 ' will be equal. This state is equivalent to Figure 8 Figure B. Furthermore, when the OFS is biased 1 OFS 2 When optimizing, the target code Z REF = 0, thereby the offset angle Set to 0 degrees, we get Figure 8 Figure C.

[0113] (Example 2)

[0114] Fig.10 FIG. 1 is a block diagram of a feedback controller 330B according to Embodiment 2. In Embodiment 1, the position detection code Z DET1 , Z DET2 Correction has been made, but even by correcting the first target code Z REF1 、Second target code Z REF2 The feedback controller 330B includes a correction circuit 350B. The correction circuit 350B performs correction on the target code Z. REF Correction is performed to generate the first target code Z REF1 And the second target code Z REF2 .

[0115] As in Example 1, the parameters include the first gain G 1, the second gain G 2 , 1st bias OFS 1 , 2nd bias OFS 2 The correction circuit 350B is used to convert the target code Z REF Multiply by the first gain G 1 Add the first offset OFS to the obtained value 1 The value Z REF ×G 1 +OFS 1 As the first object code Z REF1 .

[0116] Z REF1 =Z REF ×G 1 +OFS 1

[0117] Similarly, the correction circuit 350B can be used to convert the target code Z REF Multiply by the second gain G 2 Add the second offset OFS to the obtained value 2 The value Z REF ×G 2 +OFS 2 As the second object code Z REF2 .

[0118] Z REF2 =Z REF ×G 2 +OFS 2

[0119] The target code Z REF The first target code Z for each 1LSB REF1 The change in REF1 , the second target code Z REF1 The change in REF2 According to the correction circuit 350B, the parameters (gains G1 and G2) are determined so as to satisfy the following relationship, thereby making it possible to suppress the rotation of the lens.

[0120] ΔZ REF2 / ΔZ REF1 =ΔZ 1 / ΔZ 2

[0121] In addition, it should be noted that in the first and second embodiments, the gain G1, G2, and the offset OFS as parameters are 1 OFS 2 Take different values.

[0122] The correction circuit 350B has the same configuration as the correction circuit 350A, and includes multipliers 353_1, 353_2 and adders 354_1, 354_2. The multiplier 353_i (i=1, 2) converts the target code Z REF Multiply by the gain G i Adder 354_i adds offset OFS to the output of multiplier 353_i. i .

[0123] (Example 3)

[0124] Fig.11 It is a block diagram of the feedback controller 330C of the third embodiment.

[0125] The correction circuit 350C generates a code corresponding to the target code Z based on the parameters obtained in the calibration process. REF Corresponding rotation angle correction code Rotation angle correction code Based on the rotation angle measured during the calibration process is determined by the opposite characteristics of.

[0126] The feedback controller 330C includes a coordinate converter 345. The coordinate converter 345 generates a coordinate signal based on the first position detection code Z DET1 and the second position detection code Z DET2 , generate translation position detection code Z DET and rotation angle detection code The translation position detection code Z DET represents the translation position of the lens 132 in the Z-axis direction, and the rotation angle detection code represents the rotation angle of the lens 132 around the Y axis

[0127] exist In a relatively small case, the coordinate system Z 1 , Z 2 With coordinate system Z, It can also be simply expressed using the following relationship.

[0128] Z=Z 1 +Z 2

[0129]

[0130] The feedback controller 330C uses the target code Z REF With translation position detection code Z DET The error is close to zero and the code is corrected by the rotation angle With the rotation angle detection code The error is close to zero, and the first control code CTRLZ is generated.1 And the second control code CTRLZ 2 .

[0131] The feedback controller 330C further includes error detectors 332_1, 332_2, PID compensators 334_1, 334_2, and a coordinate inverse converter 346. The error detector 332_1 generates a target code Z REF With translation position detection code Z DET The error err Z PID compensator 334_1 receives error err Z , generate control code CTRL Z .

[0132] CTRL Z =K P ·err Z +K I ∫err Z dt+K D ·derr Z / dt

[0133] Error detector 332_2 generates rotation angle correction code With the rotation angle detection code Error PID compensator 334_1 receives error Generate control code

[0134]

[0135] The coordinate inverse converter 346 performs the conversion opposite to that of the coordinate converter 345 and converts the two control codes CTRL Z and Reverse conversion to control code CTRLZ 1 and CTRLZ 2 .

[0136]

[0137]

[0138] That is, CTRL Z Signal enables control code CTRLZ 1 , CTRLZ 2 The values ​​of these two increase and decrease equally and act as a translation control. Signal enables control code CTRLZ 1 , CTRLZ 2 The value of increases and decreases in opposite polarity and functions as a rotation control.

[0139] According to Embodiment 3, the position detection code Z can be eliminated. DET1 , Z DET2 The mismatch causes the rotation of lens 312 By targeting each target code Z REF Generate rotation angle correction code The rotation of the lens 312 is thereby suppressed.

[0140] Next, further advantages brought about by using the actuator driver 300 will be described.

[0141] As described above, according to the actuator driver 300 of the embodiment, it is possible to suppress the rotational movement of the lens 312. Thus, it is possible to simplify the structure of the lens actuator 140 that positions the lens 312.

[0142] Fig.12 It is an exploded perspective view of a lens actuator 500 of the comparative technology. The actuator 500 includes a fixed portion 510; a first movable portion 520, which can only move along the first direction (for example, the X-axis direction); and a second movable portion 530, which can only move along the second direction (for example, the Z-axis direction). The fixed portion 510 is provided with: a groove 511, which is formed along the first direction; and a plurality of balls 512, which are embedded in the groove 511. A "V"-shaped groove 522 extending along the first direction is formed on the bottom surface of the first movable portion 520. In the unassembled state, the ball 512 is embedded in the groove 522, and the first movable portion 520 moves only in the first direction relative to the fixed portion 510.

[0143] The upper surface of the first movable part 520 is provided with a groove 521 formed along the second direction and a plurality of balls 524 embedded in the groove 521. A groove 532 extending along the second direction is formed on the bottom surface of the second movable part 530. In the assembled state, the balls 524 are fitted into the groove 532, and the first movable part 520 and the second movable part 530 move only in the second direction relative to each other.

[0144] Fig.12 The structure of the actuator 500 is more complicated and the thickness is also thicker.

[0145] Fig.13 6 is an exploded perspective view of a lens actuator 600 suitable for the actuator driver 300. The actuator 600 includes a fixed portion 610 and a movable portion 620. The fixed portion 610 is provided with a plurality of balls 612. The bottom surface of the movable portion 620 is flat and does not have a groove as a guide. Therefore, the movable portion 620 can move freely above the fixed portion 610. This structure is similar to Fig.12 In comparison, the structure is simplified and the thickness can be reduced.

[0146] Fig.13 In the actuator 600, the movable part 620 can freely rotate above the fixed part 610, so a countermeasure is required in the actuator driver. Fig.13 In the actuator 600, the rotation of the movable part 620 is suppressed and it is positioned in the Z-axis direction and the X-axis direction.

[0147] (Note)

[0148] The technology disclosed in this specification can be understood as follows in one aspect.

[0149] (Item 1)

[0150] An actuator driver that drives a first actuator and a second actuator that are separately arranged in the X-axis direction and respectively position a lens in a Z-axis direction perpendicular to an image sensor;

[0151] The actuator driver comprises:

[0152] a first position detection circuit that generates a first position detection code indicating a displacement amount of the first actuator,

[0153] a second position detection circuit that generates a second position detection code indicating a displacement amount of the second actuator,

[0154] a first driving circuit that drives the first actuator according to a first control code,

[0155] a second driving circuit that drives the second actuator according to a second control code, and

[0156] a feedback controller that generates the first control code and the second control code through feedback control based on a target code indicating a target position of the lens in the Z-axis direction, the first position detection code, and the second position detection code;

[0157] The feedback controller includes a correction circuit, and generates the first control code and the second control code in a manner that is independent of the value of the target code and that maintains the optical axis of the lens parallel to the Z-axis direction. The correction circuit maintains parameters determined based on a mismatch between a distance of each 1LSB (Least Significant Bit) of the first position detection code and a distance of each 1LSB of the second position detection code.

[0158] (Item 2)

[0159] An actuator driver as described in item 1, wherein:

[0160] The correction circuit is configured to correct the first position detection code and the second position detection code based on the parameter;

[0161] The feedback controller generates the first control code in a manner that the corrected first position detection code approaches the first target code based on the target code representing the target position in the Z-axis direction of the lens, and generates the second control code in a manner that the corrected second position detection code approaches the second target code based on the target code.

[0162] (Item 3)

[0163] An actuator driver as described in item 2, wherein:

[0164] The parameters include a first gain, a second gain, a first bias, and a second bias;

[0165] The correction circuit is

[0166] The value obtained by multiplying the first position detection code by the first gain and adding the first offset is used as the corrected first position detection code.

[0167] A value obtained by multiplying the second position detection code by the second gain and adding the second offset is used as the corrected second position detection code.

[0168] (Item 4)

[0169] An actuator driver as described in item 1, wherein:

[0170] The correction circuit corrects the target code representing the target position in the Z-axis direction of the lens based on the parameter to generate a first target code, and corrects the target code based on the parameter to generate a second target code;

[0171] The feedback controller generates the first control code in such a way that the first position detection code approaches the first target code, and generates the second control code in such a way that the second position detection code approaches the second target code.

[0172] (Item 5)

[0173] An actuator driver as described in item 4, wherein:

[0174] The parameters include a first gain, a second gain, a first bias, and a second bias;

[0175] The correction circuit is

[0176] The value obtained by multiplying the target code by the first gain and adding the first offset is used as the first target code,

[0177] A value obtained by multiplying the target code by the second gain and adding the second offset is used as the second target code.

[0178] (Item 6)

[0179] An actuator driver as described in item 1, wherein:

[0180] The correction circuit generates a rotation angle correction code corresponding to the target code based on the parameter;

[0181] The feedback controller comprises:

[0182] a coordinate conversion circuit that generates a translation position detection code and a rotation angle detection code based on the first position detection code and the second position detection code, wherein the translation position detection code indicates the translation position of the lens in the Z-axis direction and the rotation angle detection code indicates the rotation angle of the lens around the Y-axis perpendicular to the X-axis direction and the Z-axis direction; and

[0183] The arithmetic circuit generates the first control code and the second control code in such a manner that an error between the target code and the translation position detection code approaches zero and an error between the rotation angle correction code and the rotation angle detection code approaches zero.

[0184] (Item 7)

[0185] The actuator driver according to any one of items 2 to 6, wherein:

[0186] The parameter is determined in the calibration step based on the relationship between the target code and the rotation angle of the lens when the target code is changed.

[0187] (Item 8)

[0188] An actuator driver as described in item 7, wherein:

[0189] The rotation angle of the lens is determined by an autocollimator.

[0190] (Item 9)

[0191] An actuator driver as described in item 7, wherein:

[0192] The rotation angle of the lens is calculated based on an image of an object captured by an image sensor through the lens.

[0193] (Item 10)

[0194] A camera module comprises: a lens supported so as to be movable in an XZ plane,

[0195] The first actuator and the second actuator are configured to sandwich the lens in a separated manner along the X-axis direction and respectively position the lens in the Z-axis direction corresponding to the optical axis direction.

[0196] The actuator driver according to any one of items 1 to 9 drives the first actuator and the second actuator based on the object code, and

[0197] An image sensor captures the image passed through the lens.

[0198] (Item 11)

[0199] The camera module of item 10, wherein:

[0200] Also includes a third actuator, which positions the lens in the X-axis direction;

[0201] The actuator driver is capable of controlling the third actuator.

[0202] (Item 12)

[0203] A camera module as described in item 10 or 11, wherein

[0204] It also includes a prism that bends the image of the subject toward the lens, and is a periscope type.

[0205] (Item 13)

[0206] An electronic device comprises the camera module according to any one of items 10 to 12.

[0207] [Explanation of Reference Numerals]

[0208] 100 Camera Module,

[0209] 110 Image sensor,

[0210] 120 prism,

[0211] 130 Imaging Optical System,

[0212] 132 lenses,

[0213] 140 lens actuator,

[0214] 142_1 Actuator No. 1,

[0215] 142_2 Second actuator,

[0216] 144_1 The first position detection element,

[0217] 144_2 The second position detection element,

[0218] 146 actuator,

[0219] 148 position detection element,

[0220] 150 Actuator for prism,

[0221] 160 gyro sensor,

[0222] 200 electronic equipment,

[0223] 210 Image Processor,

[0224] 300 Actuator Driver,

[0225] 310: arithmetic processing unit,

[0226] 320 Z-axis control system,

[0227] 322_1 1st position detection circuit,

[0228] 322_2 Second position detection circuit,

[0229] 324_1 The first driving circuit,

[0230] 324_2 The second driving circuit,

[0231] 330 Feedback Controller,

[0232] 350 correction circuit,

[0233] 360 X-axis control system,

[0234] 362 position detection circuit,

[0235] 364 drive circuit,

[0236] 366Feedback controller.

Claims

1. An actuator driver that drives a first actuator and a second actuator that are separately arranged in the X-axis direction and each position a lens in the Z-axis direction perpendicular to an image sensor; The actuator driver comprises: a first position detection circuit that generates a first position detection code indicating a displacement amount of the first actuator, a second position detection circuit that generates a second position detection code indicating a displacement amount of the second actuator, a first driving circuit that drives the first actuator according to a first control code, a second driving circuit that drives the second actuator according to a second control code, and a feedback controller that generates the first control code and the second control code through feedback control based on a target code indicating a target position of the lens in the Z-axis direction, the first position detection code, and the second position detection code; The feedback controller includes a correction circuit, and generates the first control code and the second control code in a manner that is independent of the value of the target code and that maintains the optical axis of the lens parallel to the Z-axis direction. The correction circuit maintains parameters determined based on a mismatch between a distance of each 1LSB (Least Significant Bit) of the first position detection code and a distance of each 1LSB of the second position detection code.

2. The actuator driver according to claim 1, in, The correction circuit is configured to correct the first position detection code and the second position detection code based on the parameter; The feedback controller generates the first control code in a manner that the corrected first position detection code approaches the first target code based on the target code representing the target position in the Z-axis direction of the lens, and generates the second control code in a manner that the corrected second position detection code approaches the second target code based on the target code.

3. The actuator driver according to claim 2, in, The parameters include a first gain, a second gain, a first bias, and a second bias; The correction circuit is The value obtained by multiplying the first position detection code by the first gain and adding the first offset is used as the corrected first position detection code. A value obtained by multiplying the second position detection code by the second gain and adding the second offset is used as the corrected second position detection code.

4. The actuator driver according to claim 1, in, The correction circuit corrects the target code representing the target position in the Z-axis direction of the lens based on the parameter to generate a first target code, and corrects the target code based on the parameter to generate a second target code; The feedback controller generates the first control code in such a way that the first position detection code approaches the first target code, and generates the second control code in such a way that the second position detection code approaches the second target code.

5. The actuator driver according to claim 4, in, The parameters include a first gain, a second gain, a first bias, and a second bias; The correction circuit is The value obtained by multiplying the target code by the first gain and adding the first offset is used as the first target code, A value obtained by multiplying the target code by the second gain and adding the second offset is used as the second target code.

6. The actuator driver according to claim 1, in, The correction circuit generates a rotation angle correction code corresponding to the target code based on the parameter; The feedback controller comprises: a coordinate conversion circuit that generates a translation position detection code and a rotation angle detection code based on the first position detection code and the second position detection code, wherein the translation position detection code indicates the translation position of the lens in the Z-axis direction and the rotation angle detection code indicates the rotation angle of the lens around the Y-axis perpendicular to the X-axis direction and the Z-axis direction; and The arithmetic circuit generates the first control code and the second control code in such a manner that an error between the target code and the translation position detection code approaches zero and an error between the rotation angle correction code and the rotation angle detection code approaches zero.

7. The actuator driver according to any one of claims 2 to 6, in, The parameter is determined in the calibration step based on the relationship between the target code and the rotation angle of the lens when the target code is changed.

8. The actuator driver according to claim 7, in, The rotation angle of the lens is determined by an autocollimator.

9. The actuator driver according to claim 7, in, The rotation angle of the lens is calculated based on an image of an object captured by an image sensor through the lens.

10. A camera module, include: a lens supported so as to be movable in an XZ plane, The first actuator and the second actuator are configured to sandwich the lens in a separated manner along the X-axis direction and respectively position the lens in the Z-axis direction corresponding to the optical axis direction. The actuator driver according to any one of claims 1 to 6, which drives the first actuator and the second actuator based on the object code, and An image sensor captures the image passed through the lens.

11. The camera module according to claim 10, in, Also includes a third actuator, which positions the lens in the X-axis direction; The actuator driver is capable of controlling the third actuator.

12. The camera module according to claim 10, in, It also includes a prism that bends the image of the subject toward the lens, and is a periscope type.

13. An electronic device comprising the camera module according to claim 10.

Images