Controller integrated circuit and actuator and camera module including the same

Abstract

The present disclosure provides a controller integrated circuit and an actuator and a camera module including the same, the actuator of the camera module including: a comparison unit sequentially calculating each error value by comparing a current position of a lens barrel with a target position; a controller integrated circuit (IC) generating a control signal by applying a control gain based on a proportional-integral-derivative (PID) control method to each error value sequentially input from the comparison unit to the controller integrated circuit; and a driving circuit unit generating a driving signal in response to the control signal to move the lens barrel to the target position, wherein the controller integrated circuit changes the control gain in response to the error values sequentially input including both overshoot and undershoot.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2019-0176426, filed on December 27, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety for all purposes. TECHNICAL FIELD

[0002] The disclosure relates to a controller integrated circuit (IC) and an actuator and a camera module including the same. BACKGROUND

[0003] Recently, portable communication terminals such as cellular phones, personal digital assistants (PDAs), portable personal computers (PCs), and the like have generally implemented to be capable of performing transmission of video data as well as transmission of text or audio data. According to such a trend, a camera module has become a standard in recent portable communication terminals to implement transmission of video data, video chatting, and the like.

[0004] In general, a camera module can include a lens barrel in which a lens is disposed, a housing accommodating the lens barrel, and an image sensor converting an image of a subject into an electrical signal. The camera module can be implemented as a single focus type camera module that captures an image of a subject by a fixed focus point, but recently, with the development of technology, the camera module can be implemented as a camera module including an actuator having an auto focus (AF) function. In addition, the camera module can include an actuator having an optical image stabilization (OIS) function to suppress a resolution reduction phenomenon due to hand jitter.

[0005] In order to precisely control the auto focus function and the shake correction function used in the camera module, it is necessary to displace the lens barrel to its target position. However, due to interference, the displacement of the lens barrel can not converge to the target position and oscillate.

[0006] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above information could be applicable as prior art with regard to the present disclosure. SUMMARY

[0007] The following presents a summary to provide a basic understanding of some aspects of the application. This summary is not intended to identify key / critical features of the claimed subject matter or delineate the scope of the claimed subject matter, but serves as an example of selected concepts discussed in the detailed description below.

[0008] In one general aspect, an actuator of a camera module includes a comparison unit sequentially calculating each error value by comparing a current position of a lens barrel with a target position; a controller integrated circuit (IC) generating a control signal by applying a control gain based on a proportional-integral-derivative (PID) control method to each error value sequentially input from the comparison unit to the controller IC; and a driving circuit unit generating a driving signal in response to the control signal to move the lens barrel to the target position, wherein the controller IC changes the control gain in response to the error values sequentially input including both an overshoot and an undershoot.

[0009] The controller IC can determine that a first oscillation occurs in response to the error values sequentially input including both an overshoot and an undershoot after an established time elapses.

[0010] The controller IC can change an initial control gain of the control signal to a first compensation control gain in response to the first oscillation.

[0011] The first compensation control gain can include a higher integral control gain and a lower derivative control gain than the initial control gain.

[0012] The controller IC can determine that a second oscillation occurs in response to the error values sequentially input including one of an overshoot and an undershoot after the first oscillation.

[0013] The controller IC can change the first compensation control gain of the control signal to a second compensation control gain in response to the second oscillation.

[0014] The second compensation control gain can include a higher integral control gain and a lower derivative control gain than the first compensation control gain.

[0015] The controller IC can set the second compensation control gain as an initial control gain of a next control section in response to the second oscillation.

[0016] The controller IC can determine that a second oscillation does not occur in response to the error values sequentially input not including an overshoot and not including an undershoot after the first oscillation, and maintain the first compensation control gain as a control gain of a current control section and reset an initial control gain of a next control section to a default value.

[0017] A camera module can include the actuator; a housing accommodating the lens barrel that captures an image of a subject; and an image sensor that converts the image of the subject into an electrical signal.

[0018] In another general aspect, a controller integrated circuit (IC) includes an oscillation determination unit that determines an oscillation at least twice for each error value input sequentially in one control section, a control gain change unit that changes a control gain applied to the error value based on a result of the oscillation determination by the oscillation determination unit, and a control signal generation unit that generates a control signal by applying the control gain changed by the control gain change unit to the error value, wherein the oscillation determination unit determines that a first oscillation has occurred when, among the error values input sequentially, an error value at one time point is greater than a first reference value and an error value at another time point is less than a second reference value.

[0019] The first reference value can be greater than the second reference value.

[0020] The oscillation determination unit can determine whether the first oscillation has occurred after a setup time of the error value.

[0021] In a case where the first oscillation has occurred, the control gain change unit can change an initial control gain of the control signal to a first compensation control gain, and the first compensation control gain has a higher integral control gain and a lower differential control gain than the initial control gain.

[0022] The oscillation determination unit can determine that a second oscillation has occurred when, among the error values input sequentially, an error value at one time point is greater than the first reference value or less than the second reference value after the first oscillation has occurred.

[0023] In a case where the second oscillation has occurred, the control gain change unit can change the first compensation control gain of the control signal to a second compensation control gain, and the second compensation control gain can have a higher integral control gain and a lower differential control gain than the first compensation control gain.

[0024] The control section can correspond to a frame unit of an image signal output from an image sensor.

[0025] In another general aspect, a camera module includes an actuator configured to move a lens barrel in one or more of an optical axis direction, a first direction perpendicular to the optical axis, and a second direction perpendicular to the optical axis, a housing accommodating the lens barrel, and an image sensor configured to convert an image of a subject captured by the lens barrel into an electrical signal, wherein the actuator includes a comparison unit configured to sequentially compare a current position of the lens barrel with a target position to determine sequential error values, a controller integrated circuit (IC) configured to sequentially receive each of the sequential error values and apply a control gain based on a proportional-integral-derivative (PID) control method to each error value to generate a control signal, and a driving circuit unit configured to generate a driving signal to move the lens barrel to the target position in response to the control signal, wherein the controller IC is configured to change the control gain in response to an overshoot and an undershoot of the sequential error values.

[0026] The controller IC can further include an oscillation determination unit configured to determine the overshoot from the sequential error values in response to an error value at one time point being greater than a first reference value, and determine the undershoot in response to an error value at another time point being less than a second reference value.

[0027] Other features and aspects will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is an exploded perspective view illustrating a camera module according to one or more examples of the present disclosure;

[0029] Figure 2 is a block diagram illustrating main components of an actuator used in a camera module according to one or more examples of the present disclosure;

[0030] Figure 3 is a block diagram illustrating a driving device used in an actuator according to one or more examples of the present disclosure;

[0031] Figure 4 is a block diagram illustrating a controller integrated circuit (IC) according to one or more examples of the present disclosure;

[0032] Figure 5 illustrates a graph of error values when a first overshoot occurs in a first overshoot determination part and a second overshoot occurs in a second overshoot determination part.

[0033] Figure 6A graph of an error value when the first oscillation occurs in the first oscillation determination section and the second oscillation does not occur in the second oscillation determination section is shown.

[0034] Throughout the drawings and detailed description, identical reference numbers indicate identical elements. The drawings can not be to scale and the relative dimensions of the depicted exemplary embodiments can be exaggerated, for the purpose of explanation and understanding. DETAILED DESCRIPTION

[0035] Hereinafter, while examples of the present disclosure are described in detail with reference to the accompanying drawings, it is noted that the examples are not limited thereto.

[0036] The following detailed description is provided to help the reader obtain a thorough understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents thereof will become readily apparent to those skilled in the art after having the benefit of this disclosure. For example, the order in which operations are described is not necessarily the order in which the operations are performed. Moreover, for the purpose of simplicity and clarity, detailed descriptions of well-known features can be omitted or can be provided only in block diagram form. Furthermore, descripti on of features can be replaced with similar description of other features serving the same or similar purpose.

[0037] The features described herein can be implemented in different forms and are not to be construed as limited to the examples described herein. Rather, the examples described herein have been provided for illustrative purposes so as to enable those with ordinary skill in the art to implement the methods, devices, and / or systems described herein in a variety of ways.

[0038] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, "connected to" another element, or "coupled to" another element, it can be directly on, connected, or coupled to the other element, or one or more other elements can be interposed therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no other elements interposed therebetween. As used herein, a "part" of an element can include the entire element or less than the entire element.

[0039] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items; likewise, "at least one of' includes any and all combinations of any one or more of the associated listed items.

[0040] Although terms such as "first", "second", and "third" can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, terms of a first element, a first component, a first region, a first layer, or a first section described in the examples described herein could also be termed a second element, a second component, a second region, a second layer, or a second section, without departing from the teachings of the examples.

[0041] For ease of description, spatially relative terms such as "upper", "up", "lower", "down", and equivalents thereof, can be used herein for describing an element's relationship to another element as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being "above" or "up" relative to other elements would then be oriented "below" or "down" relative to the other elements. Accordingly, the term "above" encompasses both an "above" and "below" orientation. The device can be oriented in other ways (rotated 90 degrees or at other orientations) and the spatially relative terms used herein interpreted accordingly.

[0042] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has", "having" and the like are inclusive and open-ended and specify the presence of stated features, integers, operations, components, elements, and / or groups but do not preclude the presence or addition of one or more other features, integers, operations, components, elements, and / or groups thereof.

[0043] The features of the examples described herein can be combined in various ways as will be apparent after evaluation of the disclosure. Additionally, although various configurations of examples are described herein, other configurations are possible in light of this disclosure.

[0044] Here, note that use of the term "may" with regard to an example (such as, for example, an example can include or implement something) means that at least one example includes or implements that feature, and that not all examples necessarily include or implement that feature.

[0045] An aspect of the disclosure can provide a controller integrated circuit (IC) and an actuator of a camera module including the same, which are capable of determining whether an error value is in an oscillation state by comparing each error value sequentially input with a reference value thereof, and moving a lens barrel to a target position thereof by changing a control gain when determining that the error value is in the oscillation state.

[0046] Figure 1 is an exploded perspective view illustrating a camera module according to one or more examples of the disclosure.

[0047] Referring to Figure 1 The camera module 100 according to one or more examples can include a housing unit 110, an actuator 120, and a lens module 130, and further include a ball support unit 140.

[0048] The camera module 100 can have at least one of an auto focus function and an optical image stabilization function. For example, in order for the camera module 100 to perform the auto focus function and the optical image stabilization function, the lens module 130 can be moved in each of a direction of an optical axis and a direction perpendicular to the optical axis in the housing unit 110.

[0049] The housing unit 110 can include a housing 111 and a shield case 112. The housing 111 can be formed with a material that is easy to mold. For example, the housing 111 can be formed with plastic. At least one actuator 120 can be installed in the housing 111. For example, some components of a first actuator 121 can be installed on a first side surface of the housing 111, and some components of a second actuator 122 can be installed on a second side surface, a third side surface, and a fourth side surface of the housing 111. The housing 111 can be configured to accommodate the lens module 130. For example, the housing 111 can have a space that fully or partially accommodates the lens module 130.

[0050] Six surfaces of the housing 111 can be open. For example, a hole for an image sensor can be formed on a bottom surface of the housing 111, and a rectangular hole for installing the lens module 130 can be formed on a top surface of the housing 111. In addition, the first side surface of the housing 111 can be open so that a first driving coil 121a of the first actuator 121 can be inserted thereinto, and the second side surface to the fourth side surface of the housing 111 can be open so that a second driving coil 122a of the second actuator 122 can be inserted thereinto.

[0051] The shield case 112 can be configured to cover a portion of the housing 111. For example, the shield case 112 can be configured to cover the top surface and the four side surfaces of the housing 111. Alternatively, the shield case 112 can be configured to cover only the four side surfaces of the housing 111, or can be configured to partially cover the top surface and the four side surfaces of the housing 111. The shield case 112 can block electromagnetic waves that occur during driving of the camera module. Electromagnetic waves can occur when the camera module is driven, and in the case where the electromagnetic waves are emitted outward from the camera module, the electromagnetic waves can affect other electronic components to cause communication errors or malfunctions between the electronic components. To prevent such problems, the shield case 112 can be formed of metal and grounded to a ground pad of a substrate mounted on the bottom surface of the housing 111 to block the electromagnetic waves.

[0052] The number of the actuators 120 can be plural. For example, the actuators 120 can include a first actuator 121 configured to move the lens module 130 in the Z-axis direction and a second actuator 122 configured to move the lens module 130 in the X-axis and Y-axis directions.

[0053] The first actuator 121 can be mounted on the housing 111 and the first frame 131 of the lens module 130. For example, some components of the first actuator 121 can be mounted on the first side surface of the housing 111, and other components of the first actuator 121 can be mounted on the first side surface of the first frame 131. The first actuator 121 can move the lens module 130 in the optical axis direction (Z-axis direction). For example, the first actuator 121 can include a first driving coil 121a, a first magnet 121b, a first substrate 121c, and a first position detector 121d. The first driving coil 121a and the first position detector 121d can be formed on the first substrate 121c. The first substrate 121c can be mounted on the first side surface of the housing 111, and the first magnet 121b can be mounted on the first side surface 131c of the first frame 131 facing the first substrate 121c.

[0054] A first driving device (not shown) that supplies a driving signal to the first driving coil 121a can be disposed on the first substrate 121c. The first driving device can apply a driving signal to the first driving coil 121a to supply a driving force to the first magnet 121b. The first driving device can include a driver integrated circuit (IC) that supplies a driving signal to the first driving coil 121a. For example, when a driving signal is applied from the first driving device to the first driving coil 121a, a magnetic flux can be generated in the first driving coil 121a. Here, the magnetic flux generated in the first driving coil 121a can interact with the magnetic field of the first magnet 121b to generate a driving force that enables the first frame 131 and the lens barrel 134 to relatively move with respect to the housing 111 according to the Fleming's left-hand rule. The first driving device can include an H-bridge circuit that is bidirectionally driven, and thus can apply a driving signal to the first driving coil 121a.

[0055] The lens barrel 134 can move in the same direction as the movement direction of the first frame 131 by the movement of the first frame 131. The first actuator 121 can sense the magnitude of the magnetic field generated by the first magnet 121b using the first position detector 121d, and thus detect the position of the first frame 131 and the position of the lens barrel 134. For example, the first position detector 121d can include a Hall sensor.

[0056] The second actuator 122 can be mounted on the housing 111 and the third frame 133 of the lens module 130. For example, some components of the second actuator 122 can be mounted on the second side surface to the fourth side surface of the housing 111, and other components of the second actuator 122 can be mounted on the second side surface to the fourth side surface of the third frame 133. The second actuator 122 can be mounted on some of the second side surface to the fourth side surface of the housing 111 and the second side surface to the fourth side surface of the third frame 133, or can be mounted on the second corner to the fourth corner included at the second side surface to the fourth side surface in contact with each other.

[0057] The second actuator 122 can include components for moving the lens module 130 in a direction perpendicular to the optical axis. For example, the second actuator 122 can include a plurality of second driving coils 122a, a plurality of second magnets 122b, a second substrate 122c, and a plurality of second position detectors 122d.

[0058] The plurality of second driving coils 122a and the plurality of second position detectors 122d can be formed on the second substrate 122c. The second substrate 122c can have a substantially rectangular shape with one side open, and be mounted to surround the second side surface to the fourth side surface of the housing 111. The plurality of second magnets 122b can be mounted on the second side surface to the fourth side surface of the third frame 133, respectively, to face the second substrate 122c.

[0059] A second driving device (not shown) that supplies a driving signal to the second driving coil 122a can be disposed on the second substrate 122c. The second driving device can apply a driving signal to the second driving coil 122a to supply a driving force to the second magnets 122b. The second driving device can include a driver integrated circuit (IC) that supplies a driving signal to the second driving coil 122a. For example, when a driving signal is supplied from the second driving device to the second driving coil 122a, a magnetic flux can be generated from the second driving coil 122a. Here, the magnetic flux generated from the second driving coil 122a can interact with the magnetic field of the second magnets 122b. The second driving device can change the magnitude and direction of the magnetic force generated between the plurality of second driving coils 122a and the plurality of second magnets 122b to enable relative movement of the second frame 132 or the third frame 133 with respect to the first frame 131. The second driving device can include an H-bridge circuit that is bidirectionally driven to apply a driving signal to the second driving coil 122a.

[0060] The lens barrel 134 can move in the same direction as the movement direction of the second frame 132 or the third frame 133 by the movement of the second frame 132 or the third frame 133. The second actuator 122 can sense the magnitude of the magnetic field generated by the second magnets 122b using the second position detector 122d to detect the position of the lens barrel 134 as well as the position of the second frame 132 and the position of the third frame 133. For example, the second position detector 122d can include a Hall sensor. The second position detector 122d can include at least two Hall sensors to detect the position of the lens barrel 134 as well as the second frame 132 and the third frame 133 in two directions perpendicular to the optical axis.

[0061] The lens module 130 can be mounted in the housing unit 110. For example, the lens module 130 can be accommodated in an accommodation space formed by the housing 111 and the shield case 112 to be movable in at least three axial directions. The lens module 130 can include a plurality of frames. For example, the lens module 130 can include a first frame 131, a second frame 132, and a third frame 133.

[0062] The first frame 131 can be configured to be movable with respect to the housing 111. For example, the first frame 131 can be movable in the optical axis direction (Z-axis direction) of the housing 111 by the first actuator 121. A plurality of guide grooves 131a and 131b can be formed in the first frame 131. For example, a first guide groove 131a extending in an elongated shape in the optical axis direction (Z-axis direction) can be formed in a first side surface of the first frame 131, and second guide grooves 131b extending in an elongated shape in a first direction (Y-axis direction) perpendicular to the optical axis can be formed in four corner portions of an inner bottom surface of the first frame 131, respectively. The first frame 131 can be manufactured such that at least three side surfaces of the first frame 131 are open. For example, second to fourth side surfaces of the first frame 131 can be open such that the second magnet 122b mounted on the third frame 133 and the second driving coil 122a mounted on the housing 111 can face each other.

[0063] The second frame 132 can be mounted in the first frame 131. For example, the second frame 132 can be mounted in an inner space of the first frame 131. The second frame 132 can be configured to be movable with respect to the first frame 131 in the first direction (Y-axis direction) perpendicular to the optical axis. For example, the second frame 132 can be movable in the first direction (Y-axis direction) perpendicular to the optical axis along the second guide grooves 131b of the first frame 131. A plurality of guide grooves 132a can be formed in the second frame 132. For example, four third guide grooves 132a extending in an elongated shape in a second direction (X-axis direction) perpendicular to the optical axis can be formed in corner portions of the second frame 132, respectively.

[0064] The third frame 133 can be mounted on the second frame 132. For example, the third frame 133 can be mounted on a top surface of the second frame 132. The third frame 133 can be configured to be movable with respect to the second frame 132 in the second direction (X-axis direction) perpendicular to the optical axis. For example, the third frame 133 can be movable in the second direction (X-axis direction) perpendicular to the optical axis along the third guide grooves 132a of the second frame 132. A plurality of second magnets 122b can be mounted on the third frame 133. For example, at least two second magnets 122b can be mounted on second to fourth side surfaces of the third frame 133, respectively. Alternatively, for example, three second magnets 122b can be mounted on second to fourth side surfaces of the third frame 133, respectively. The lens module 130 can include a lens barrel 134. For example, the lens module 130 can include the lens barrel 134 including one or more lenses. The lens barrel 134 can have a hollow cylindrical shape to accommodate at least one lens that captures an image of a subject, and the lens can be disposed in the lens barrel 134 along the optical axis. At least one lens can be stacked according to a design of the lens barrel 134, and the at least one lens can have optical properties such as the same refractive index or different refractive indices, etc.

[0065] The lens barrel 134 can be mounted in the third frame 133. For example, the lens barrel 134 can be fitted into the third frame 133, thereby moving integrally with the third frame 133. The lens barrel 134 can be configured to move in the optical axis direction (Z-axis direction) and in a direction perpendicular to the optical axis (X-axis direction and Y-axis direction). For example, the lens barrel 134 can move in the optical axis direction (Z-axis direction) by the first actuator 121 and in a direction perpendicular to the optical axis (X-axis direction and Y-axis direction) by the second actuator 122.

[0066] The ball support unit 140 can guide the movement of the lens module 130. For example, the ball support unit 140 can be configured such that the lens module 130 moves smoothly in the optical axis direction and in a direction perpendicular to the optical axis. The ball support unit 140 can include a first ball support 141, a second ball support 142, and a third ball support 143. For example, the first ball support 141 can be disposed in the first guide groove 131a of the first frame 131 such that the first frame 131 moves smoothly in the optical axis direction. For another example, the second ball support 142 can be disposed in the second guide groove 131b of the first frame 131 such that the second frame 132 moves smoothly in a first direction perpendicular to the optical axis. For another example, the third ball support 143 can be disposed in the third guide groove 132a of the second frame 132 such that the third frame 133 moves smoothly in a second direction perpendicular to the optical axis.

[0067] Each of the first ball support 141 and the second ball support 142 can include at least three balls, and the at least three balls of the first ball support 141 and the at least three balls of the second ball support 142 can be disposed in the first guide groove 131a and the second guide groove 131b, respectively.

[0068] A lubricating material for reducing friction and noise can be filled in all parts in which the ball support unit 140 is disposed. For example, a viscous fluid can be injected into the respective guide grooves 131a, 131b, and 132a. Grease having excellent viscosity and lubricating properties can be used as the viscous fluid.

[0069] Figure 2 is a block diagram illustrating main components of an actuator used in a camera module according to one or more examples of the disclosure.

[0070] The actuator 200 according to one or more examples can include a driving device 210, a driving coil 220, a target unit to be detected 230, and a position detection unit 240. Figure 2 The actuator 200 according to the present example in Figure 1 the first actuator 121 or the second actuator 122 in

[0071] When Figure 2 the actuator 200 in Figure 1 corresponds to the first actuator 121 in Figure 2 , the actuator 200 can move the lens barrel in the optical axis direction to perform an auto focus (AF) function of the camera module. Accordingly, when the actuator 200 in performs the auto focus function, the driving device 210 can apply a driving signal to the driving coil 220 to provide a driving force in the optical axis direction to the magnet.

[0072] Further, when the actuator 200 in Figure 2 corresponds to the second actuator 122 in Figure 1 , the actuator 200 can move the lens barrel in a direction perpendicular to the optical axis to perform an optical image stabilization (OIS) function of the camera module. Accordingly, when the actuator 200 in Figure 2 performs the OIS function, the driving device 210 can apply a driving signal to the driving coil 220 to provide a driving force in a direction perpendicular to the optical axis to the magnet.

[0073] The driving device 210 can generate a driving signal Sdr based on an input signal Sin input from an external source and a feedback signal Sf generated from the position detection unit 240, and can provide the generated driving signal Sdr to the driving coil 220. The target position of the lens barrel can be determined through the input signal Sin.

[0074] When the driving signal Sdr is applied from the driving device 210 to the driving coil 220, the lens barrel can be moved by electromagnetic interaction between the driving coil 220 and the magnet.

[0075] The to-be-detected target unit 230 can be disposed at one side of the lens barrel to move in the same direction as the movement direction of the lens barrel. According to another example, in addition to the lens barrel, the to-be-detected target unit 230 can be disposed on one or more of a carrier coupled to the lens barrel and a plurality of frames.

[0076] The to-be-detected target unit 230 can be formed with one of a magnetic material and a conductor. For example, the to-be-detected target unit 230 can correspond to the first magnet 121b or the second magnet 122b in Figure 1 . According to another example, a separate element can be disposed to implement the to-be-detected target unit 230.

[0077] The position detection unit 240 can detect the position of the to-be-detected target unit 230 to generate a feedback signal Sf, and provide the feedback signal Sf to the driving device 210, wherein the to-be-detected target unit 230 is moved by electromagnetic interaction between the magnet and the driving coil 220.

[0078] The position detection unit 240 can include a position detector and an analog-to-digital converter. The position detector of the position detection unit 240 can correspond to the first position detector 121d or the second position detector 122d in FIG. 1. Figure 1 The position detector can detect the position of the lens barrel by detecting the size of the magnetic field of the target unit 230 to be detected. The analog-to-digital converter can convert an analog signal output from the position detector into a digital signal.

[0079] When the feedback signal Sf is provided to the driving device 210, the driving device 210 can compare the input signal Sin with the feedback signal Sf to generate the driving signal Sdr again. That is, the driving device 210 can be driven in a closed-loop type in which the input signal Sin and the feedback signal Sf are compared with each other. The driving device 210 of the closed-loop type can be driven to reduce an error between the target position of the lens barrel included in the input signal Sin and the current position of the lens barrel determined based on the feedback signal Sf. The driving of the closed-loop type can have improved linearity, accuracy, and repeatability compared to the open-loop system type.

[0080] The driving device 210 can include an H-bridge circuit bidirectionally driven to apply the driving signal to the driving coil 220 (for example, the second driving coil 122a).

[0081] Figure 3 is a block diagram illustrating a driving device used in an actuator according to one or more examples of the present disclosure.

[0082] The driving device 210 can include a comparison unit 212, a controller integrated circuit (IC) 214, and a driving circuit unit 216.

[0083] The comparison unit 212 can compare the input signal Sin with the feedback signal Sf. The comparison unit 212 can calculate an error value by comparing the target position of the lens barrel included in the input signal Sin with the current position of the lens barrel included in the feedback signal Sf. For example, the comparison unit 212 can sequentially calculate each error value by comparing the input signal Sin with the feedback signal Sf. The movement distance and the movement direction of the lens barrel can be determined by the error value calculated in the comparison unit 212.

[0084] The controller IC 214 can generate a control signal by applying a control gain to the error value provided from the comparison unit 212. For example, the controller IC 214 can include a proportional-integral-derivative (PID) controller to perform PID-type control. The controller IC 214 can generate a control signal by applying a control gain based on a PID control method.

[0085] The controller IC 214 can perform control proportional to the size of the error value in the current state based on proportional control, perform control for reducing a steady-state error based on integral control, and perform control for preventing rapid change to reduce overshoot based on derivative control.

[0086] The PID-type control can be represented by Equation 1. P The proportional control gain Kp can represent a gain for proportional control. I The integral control gain Ki can represent a gain for integral control. D The derivative control gain Kd can represent a gain for derivative control, and e(t) can represent a function indicating a change in the error value.

[0087] Equation 1

[0088]

[0089] When the PID-type control is performed, the controller IC 214 can generate a control signal by applying each of the proportional control gain Kp P , the integral control gain Ki I , and the derivative control gain Kd D to an error value corresponding to a difference between a target position of the lens barrel and a current position of the lens barrel.

[0090] The driving circuit unit 216 can generate a driving signal based on the control signal provided from the controller IC 214. The lens barrel can be moved to the target position by the driving signal generated in the driving circuit unit 216. The driving circuit unit 216 can include an H-bridge circuit bidirectionally driven to apply the driving signal to the driving coil 220 in a voice coil motor method. When the driving circuit unit 216 is driven in the voice coil motor method, the control signal provided from the controller IC 214 can be applied to a control terminal of a switching element included in the H-bridge circuit.

[0091] However, even when the control signal is generated by applying the control gain to the error value, the displacement position of the lens barrel can not converge to the target position and oscillate. The oscillation of the lens barrel can be caused by the oscillation of the error value. Here, the "oscillation" can refer to a state in which the error value cannot enter a normal state due to disturbance and overshoot or undershoot continues to occur even after a settling time elapses.

[0092] According to one or more examples, the controller IC 214 can determine whether the error value is in an oscillation state by comparing each error value sequentially input thereto with a reference value thereof, and when it is determined that the error value is in the oscillation state, can move the lens barrel to the target position by changing the control gain.

[0093] Figure 4is a block diagram illustrating a controller integrated circuit (IC) according to one or more examples of the present disclosure.

[0094] Referring to Figure 4 According to one or more examples, the controller IC 214 can include an oscillation determination unit 214a, a control gain change unit 214b, and a control signal generation unit 214c.

[0095] The oscillation determination unit 214a can determine whether an oscillation has occurred by comparing each error value sequentially input from the comparison unit 212 in the lens barrel control device 200 with a first reference value and a second reference value. For example, the first reference value can be greater than a value of a target position of the lens barrel, and the second reference value can be less than the value of the target position of the lens barrel. Figure 3

[0096] When it is determined that an oscillation has occurred based on a result of the oscillation determination of the oscillation determination unit 214a, the control gain change unit 214b can change a control gain currently applied to the error value.

[0097] The control signal generation unit 214c can generate a control signal based on an initial control gain in an initial state thereof. For example, the initial control gain can be set to a default value. When an oscillation occurs, the control signal generation unit 214c can generate a control signal based on a control gain changed by the control gain change unit 214b.

[0098] The oscillation determination unit 214a can determine whether an oscillation has occurred for each of a plurality of control sections. The oscillation determination unit 214a can determine whether an oscillation has occurred based on an error value after an established time among sequentially input error values. Here, the established time can refer to a time required for an error value to enter a stable state when an oscillation does not occur, which can be determined in advance. For example, each of the plurality of control sections can correspond to a frame unit of an image signal output from an image sensor.

[0099] According to one or more examples, it can be determined in real time whether an oscillation has occurred by determining whether an oscillation has occurred for each frame unit of an image signal.

[0100] ​The oscillation determination unit 214a can make at least two determinations as to whether an oscillation has occurred in one control section. Hereinafter, it is assumed that the oscillation determination unit 214a makes two determinations as to whether an oscillation has occurred in one control section for the sake of convenience of explanation. Here, in the sections in which the determinations as to whether an oscillation has occurred are made twice, the section in which the determination as to whether an oscillation has occurred is made first can be referred to as a first oscillation determination section, and the section in which the determination as to whether an oscillation has occurred is made second can be referred to as a second oscillation determination section. Here, the first oscillation determination section and the second oscillation determination section can each correspond to a section of the error values that are sequentially input after the establishment time. For example, the first oscillation determination section can correspond to a first time period of the error values after the establishment time elapses, and the second oscillation determination section can correspond to a second time period of the error values after the establishment time elapses.

[0101] The oscillation determination unit 214a can determine that the first oscillation has occurred in a case where, in the first oscillation determination section, the error value at one time point among the error values that are sequentially input is greater than the first reference value and the error value at another time point is less than the second reference value. That is, the oscillation determination unit 214a can determine that the first oscillation has occurred in a case where both an overshoot and an undershoot have occurred in the first oscillation determination section.

[0102] Alternatively, the oscillation determination unit 214a can determine that the first oscillation has not occurred in a case where, in the first oscillation determination section, all of the error values that are sequentially input are less than the first reference value or all of the error values that are sequentially input are greater than the second reference value.

[0103] According to one or more examples, the first oscillation can be determined to have occurred in a case where, in the first oscillation determination section, both an error value greater than the first reference value and an error value less than the second reference value are detected. Thus, the reliability of the oscillation determination can be improved.

[0104] When it is determined that the first oscillation has occurred in the first oscillation determination section, the oscillation determination unit 214a can subsequently determine whether the second oscillation has occurred in the second oscillation determination section.

[0105] The oscillation determination unit 214a can determine that the second oscillation has occurred in a case where, in the second oscillation determination section, the error value at one time point among the error values that are sequentially input is greater than the first reference value or less than the second reference value. That is, the oscillation determination unit 214a can determine that the second oscillation has occurred in a case where either an overshoot or an undershoot has occurred in the second oscillation determination section.

[0106] Alternatively, the oscillation determination unit 214a can determine that the second oscillation does not occur in a case where all of the error values input sequentially in the second oscillation determination section are smaller than the first reference value and larger than the second reference value. That is, the oscillation determination unit 214a can determine that the second oscillation does not occur in a case where neither overshoot nor undershoot occurs in the second oscillation determination section.

[0107] Unlike the first oscillation determination section, the oscillation determination unit 214a can determine that the second oscillation occurs in a case where either overshoot or undershoot occurs in the second oscillation determination section. Thus, the oscillation determination unit 214a can quickly modify the occurring oscillation.

[0108] When it is determined that the first oscillation occurs in the first oscillation determination section, the control gain changing unit 214b can change the initial control gain to a first compensation control gain. For example, the first compensation control gain can have a higher integral control gain K I , than the initial control gain. For another example, the first compensation control gain can have a lower derivative control gain K D , than the initial control gain. For yet another example, the first compensation control gain can have a higher integral control gain K I and a lower derivative control gain K D , than the initial control gain.

[0109] Further, when it is determined that the second oscillation occurs in the second oscillation determination section, the control gain changing unit 214b can change the first compensation control gain to a second compensation control gain. For example, the second compensation control gain can have a higher integral control gain K I , than the first compensation control gain. For another example, the second compensation control gain can have a lower derivative control gain K D , than the first compensation control gain. Further, the second compensation control gain can have a higher integral control gain K I and a lower derivative control gain K D , than the first compensation control gain.

[0110] It can be assumed that the first oscillation occurs in the first oscillation determination section, and the second oscillation does not occur in the second oscillation determination section. In this case, the control gain changing unit 214b can maintain the first compensation control gain until the end of the current control section, and reset the initial control gain of the next control section to a default value.

[0111] However, it can be assumed that the first oscillation occurs in the first oscillation determination section, and the second oscillation occurs in the second oscillation determination section. In this case, in order to quickly end the oscillation state, the control gain changing unit 214b can set the second compensation control gain applied at the end of the current control section as the initial control gain of the next control section.

[0112] Figure 5 A graph of error values when the first oscillation occurs in the first oscillation determination section and the second oscillation occurs in the second oscillation determination section is shown. Figure 5 The error values shown in (a) can correspond to error values after the establishment time in the graph.

[0113] Referring to Figure 5 It can be confirmed that, in the graph of error values, the error values do not converge to the target position and remain in an oscillation state by overshoot and undershoot. In Figure 5 The first oscillation determination section can correspond to a first time period of error values, and the second oscillation determination section can correspond to a second time period of error values in (a).

[0114] Referring to Figure 5 After the time point T1 of the first oscillation determination section D1, the error value is greater than the first reference value, and after the time point T2 of the first oscillation determination section D1, the error value is less than the second reference value. Therefore, the oscillation determination unit 214a can determine that the first oscillation occurs at the time point T2.

[0115] When it is determined that the first oscillation occurs in the first oscillation determination section D1, the control gain change unit 214b can change the initial control gain currently applied to the control signal generation unit 214c to the first compensation control gain.

[0116] When the initial control gain is changed to the first compensation control gain by the control gain change unit 214b, the control signal generation unit 214c can generate a control signal based on the first compensation control gain.

[0117] Referring again to Figure 5 After the time point T3 of the second oscillation determination section D2, the error value is greater than the first reference value. Therefore, the oscillation determination unit 214a can determine that the second oscillation occurs at the time point T3.

[0118] When it is determined that the second oscillation occurs in the second oscillation determination section D2, the control gain change unit 214b can change the first compensation control gain currently applied to the control signal generation unit 214c to the second compensation control gain. Also, the first oscillation occurs in the first oscillation determination section, and the second oscillation occurs in the second oscillation determination section; therefore, the control gain change unit 214b can also set the second compensation control gain as the initial control gain of the next control section.

[0119] When the first compensation control gain is changed to the second compensation control gain by the control gain change unit 214b, the control signal generation unit 214c can generate a control signal based on the second compensation control gain.

[0120] Figure 6 A graph of the error value when the first oscillation occurs in the first oscillation determination section and the second oscillation does not occur in the second oscillation determination section is shown. Figure 6 The graph is similar to Figure 5 the graph. Therefore, further description can omit repeated explanation and focus on the difference.

[0121] Referring to Figure 6 , the error value is greater than the first reference value after the time point T1 of the first oscillation determination section D1, and the error value is smaller than the second reference value after the time point T2 of the first oscillation determination section D1. Therefore, the oscillation determination unit 214a can determine that the first oscillation occurs at the time point T2.

[0122] When it is determined that the first oscillation occurs in the first oscillation determination section D1, the control gain changing unit 214b can change the initial control gain currently applied to the control signal generating unit 214c to the first compensation control gain.

[0123] When the initial control gain is changed to the first compensation control gain by the control gain changing unit 214b, the control signal generating unit 214c can generate the control signal based on the first compensation control gain.

[0124] Referring again to Figure 6 , in the second oscillation determination section D2, the error value is smaller than the first reference value and greater than the second reference value. Therefore, the oscillation determination unit 214a can determine that the second oscillation does not occur.

[0125] In this case, the control gain changing unit 214b can maintain the first compensation control gain until the current frame ends, and reset the initial control gain of the next control section to the default value.

[0126] As set forth above, according to the examples described herein, it is possible to determine in real time whether an oscillation occurs by determining whether an oscillation occurs for each frame unit of an image signal.

[0127] According to the examples described herein, it is possible to determine that an oscillation occurs in a case where both overshoot and undershoot occur in the first oscillation determination section. Therefore, it is possible to improve the reliability of oscillation determination.

[0128] Unlike in the first oscillation determination section, it is possible to determine that the second oscillation occurs in a case where either overshoot or undershoot occurs in the second oscillation determination section. Therefore, it is possible to quickly modify an oscillation that occurs.

[0129] While specific examples have been shown and described, it will be apparent to those of ordinary skill in the art having the benefit of this disclosure that changes in form and detail can be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the described systems, architectures, devices, or circuits are combined in a different manner, and / or if the described components are replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is not defined by the specific embodiments discussed, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.

Claims

1. An actuator of a camera module, comprising: a comparison unit sequentially calculating each error value by comparing a current position of a lens barrel with a target position; a controller integrated circuit generating a control signal by applying a control gain based on a proportional-integral-derivative control method to each error value sequentially input from the comparison unit to the controller integrated circuit; and a driving circuit unit generating a driving signal in response to the control signal to move the lens barrel to the target position, wherein the controller integrated circuit changes the control gain in response to the error values sequentially input including both overshoot and undershoot, wherein the controller integrated circuit determines that a first oscillation occurs in response to the error values sequentially input including both overshoot and undershoot after an established time elapses, wherein the controller integrated circuit determines that a second oscillation occurs in response to the error values sequentially input including one of overshoot and undershoot after the first oscillation, wherein the controller integrated circuit changes an initial control gain of the control signal to a first compensation control gain in response to the first oscillation, and the controller integrated circuit changes the first compensation control gain of the control signal to a second compensation control gain in response to the second oscillation.

2. The actuator of claim 1, wherein, The first compensation control gain includes a higher integral control gain and a lower derivative control gain than the initial control gain.

3. The actuator of claim 1, wherein, The second compensation control gain includes a higher integral control gain and a lower derivative control gain than the first compensation control gain.

4. The actuator of claim 3, wherein, The controller integrated circuit sets the second compensation control gain as an initial control gain of a next control section in response to the second oscillation.

5. The actuator of claim 1, wherein, The controller integrated circuit determines that a second oscillation does not occur in response to the error values sequentially input not including overshoot and not including undershoot after the first oscillation, and maintains the first compensation control gain as a control gain of a current control section and resets an initial control gain of a next control section to a default value. 6.A camera module, comprising: the actuator according to any one of claims 1-5; a housing accommodating the lens barrel that captures an image of a subject; and an image sensor that converts the image of the subject into an electrical signal. 7.A controller integrated circuit, comprising: an oscillation determination unit making at least two determinations of an oscillation of each error value sequentially input in one control section; a control gain change unit changing a control gain applied to the error value based on a result of the oscillation determination of the oscillation determination unit; and a control signal generation unit generating a control signal by applying the control gain changed by the control gain change unit to the error value, wherein the oscillation determination unit determines that a first oscillation occurs in a case where, among the error values sequentially input, an error value at one time point is greater than a first reference value and an error value at another time point is less than a second reference value, wherein the oscillation determination unit determines that the second oscillation has occurred when, among the sequentially input error values, an error value at a time point after the first oscillation has occurred is greater than the first reference value or less than the second reference value, wherein the control gain changing unit changes an initial control gain of the control signal to a first compensation control gain in a case where the first oscillation has occurred, and wherein the control gain changing unit changes the first compensation control gain of the control signal to a second compensation control gain in a case where the second oscillation has occurred.

8. The controller integrated circuit of claim 7, wherein, the first reference value is greater than the second reference value.

9. The controller integrated circuit of claim 7, wherein, the oscillation determination unit determines whether the first oscillation has occurred after a set time of the error value.

10. The controller integrated circuit according to claim 9, the first compensation control gain has a higher integral control gain and a lower differential control gain than the initial control gain.

11. The controller integrated circuit according to claim 10, the second compensation control gain has a higher integral control gain and a lower differential control gain than the first compensation control gain.

12. The controller integrated circuit of claim 7, wherein, the control section corresponds to a frame unit of an image signal output from an image sensor.

13. A camera module comprising: an actuator configured to move a lens barrel in one or more of an optical axis direction, a first direction perpendicular to the optical axis, and a second direction perpendicular to the optical axis; a housing that houses the lens barrel; and an image sensor configured to convert an image of a subject captured by the lens barrel into an electrical signal, wherein the actuator includes: a comparison unit configured to sequentially compare a current position of the lens barrel with a target position to determine sequential error values; a controller integrated circuit configured to sequentially receive each of the sequential error values and apply a control gain based on a proportional-integral-differential control method to each error value to generate a control signal; and a drive circuit unit configured to generate a drive signal in response to the control signal to move the lens barrel to the target position, wherein the controller integrated circuit is configured to change the control gain in response to overshoot and undershoot of the sequential error values, the controller integrated circuit determines that a first oscillation has occurred in response to the sequential error values including both overshoot and undershoot after a set time, the controller integrated circuit determines that a second oscillation has occurred in response to the sequential error values including one of overshoot and undershoot after the first oscillation, wherein the controller integrated circuit changes an initial control gain of the control signal to a first compensation control gain in response to the first oscillation, and the controller integrated circuit changes the first compensation control gain of the control signal to a second compensation control gain in response to the second oscillation. ​ 14. The camera module of claim 13, wherein, The controller integrated circuit includes an overshoot determination unit configured to determine the overshoot from the sequential error values in response to an error value at one point in time being greater than a first reference value and to determine the undershoot in response to an error value at another point in time being less than a second reference value.

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