Camera module and control method thereof

Abstract

In an embodiment, disclosed is a camera module comprising: a first camera actuator for reflecting incident light; a second camera actuator through which the light reflected by the first camera actuator passes; and an image sensor for receiving the light having passed through the second camera actuator, wherein the first camera actuator includes: a mover; a first prism disposed on the mover; a driving unit for driving the first prism; and a control unit for controlling the driving unit, wherein the control unit sets a target rotation angle of the first prism and controls the driving unit, and the control unit controls the driving unit to drive the first prism to the target rotation angle over a plurality of steps having different rotation angles.

Description

Camera module and control method thereof

[0001] An exemplary embodiment relates to a camera module and a method for controlling the same.

[0002] A camera is a device that captures subjects in photos or videos, and it is mounted on portable devices, drones, vehicles, etc. To improve image quality, camera modules may feature Image Stabilization (IS) to correct or prevent image shake caused by user movement, Auto Focusing (AF) to automatically adjust the distance between the image sensor and the lens to align the lens focal length, and Zooming to increase or decrease the magnification of distant subjects using a zoom lens.

[0003] Meanwhile, as image sensors increase in pixel count, the resolution rises and the size of the pixels decreases; consequently, as pixels become smaller, the amount of light received over the same period of time decreases. Therefore, in high-pixel cameras, image blur caused by hand shake resulting from slow shutter speeds in dark environments can appear more severe. A representative example of image stabilization (IS) technology is optical image stabilization (OIS), which corrects motion by changing the path of light.

[0004] The camera module consists of multiple lens groups and prisms, and by controlling the position of the prisms, it can maintain the center point when screen shifts occur due to external forces, thereby ensuring suppression performance. In the case of a continuous zoom module, the structure allows for precise control of the prisms using a driver IC. To maintain the center point when instantaneous screen shifts occur in the module, movement must be maintained within a specific frequency and period without an error range. When the prism is rotated to maintain the center, the control force acts in proportion to the size of the target. Consequently, the target code generates a large overshoot and undergoes a stabilization process. Such overshoot requires stabilization time, causes delays in control time, and presents disadvantages in terms of stability.

[0005] An embodiment provides a camera module with improved optical performance and a method for controlling the same.

[0006] In addition, a camera module with increased driving accuracy and driving efficiency and a control method thereof are provided.

[0007] In addition, a camera module and a control method thereof are provided that can prevent overshoot phenomena and improve driving stability.

[0008] The problem to be solved in the embodiments is not limited thereto, and may also include the purpose or effect that can be identified from the means of solving the problem or the form of implementation described below.

[0009] A camera module according to an embodiment includes a first camera actuator that reflects incident light; a second camera actuator that passes light reflected by the first camera actuator; and an image sensor that receives light that has passed through the second camera actuator, wherein the first camera actuator includes a mover, a first prism disposed on the mover, a driving unit that drives the first prism, and a control unit that controls the driving unit, wherein the control unit controls the driving unit by setting a target rotation angle of the first prism, and the control unit can control the driving unit to drive the first prism to the target rotation angle over a plurality of steps of different rotation angles.

[0010] The above control unit controls the driving unit according to a plurality of control cycles, and the target rotation angle of the first prism corresponding to each of the plurality of control cycles may be different.

[0011] The sizes of the plurality of control cycles may be the same or different from each other, and the plurality of control cycles may include a first control cycle to a tenth control cycle.

[0012] The above target rotation angle may include a first target rotation angle to a tenth target rotation angle corresponding to each of the first to tenth control cycles.

[0013] The above driving unit can rotate the mover to the first target rotation angle and then, after a certain time interval, rotate it to the second target rotation angle which is greater than the first target rotation angle.

[0014] The sum of the control amounts of the control unit corresponding to each of the plurality of control cycles above may be the same as the target control amount of the control unit.

[0015] The sizes of the plurality of control cycles are equal to each other, and in each control cycle, the driving unit can rotate the first prism by a first unit angle.

[0016] The above control unit can adjust the size of the first unit angle.

[0017] The above control unit can adjust the size of the control cycle.

[0018] A camera module control method according to an embodiment may include: a step in which a control unit sets a target control amount and a unit control amount obtained by dividing the target control amount; a step in which the control unit sets a control cycle corresponding to the unit control amount; a step in which the control unit controls a driving unit according to the unit control amount and the control cycle; and a step in which the driving unit rotates a mover and a first prism according to the control of the control unit.

[0019] A camera module control method according to an embodiment may include the step of the control unit adjusting the size of the control cycle; and the step of the control unit adjusting the size of the unit control amount.

[0020] According to an embodiment, a camera module with improved optical performance and a method for controlling the same can be provided.

[0021] In addition, a camera module with increased driving accuracy and driving efficiency and a method for controlling the same can be provided.

[0022] In addition, a camera module and a control method thereof can be provided to prevent overshoot and improve driving stability.

[0023] The various and beneficial advantages and effects of the present invention are not limited to those described above and may be more easily understood in the process of explaining specific embodiments of the present invention.

[0024] FIG. 1 is a perspective view of a camera module according to an embodiment, and

[0025] FIG. 2 is an exploded perspective view of a camera module according to an embodiment, and

[0026] FIG. 3 is a cross-sectional view of a camera module cut along AA' in FIG. 1, and

[0027] FIG. 4 is a perspective view of a first camera actuator according to an embodiment, and

[0028] FIG. 5 is a cross-sectional view of the first camera actuator cut at BB' in FIG. 4, and

[0029] FIG. 6 is a cross-sectional view of the first camera actuator cut along CC' in FIG. 4, and

[0030] FIG. 7 is a graph showing the overshoot phenomenon according to the control method of a conventional camera module, and

[0031] FIG. 8 is a graph for explaining a control method of a camera module according to an embodiment, and

[0032] FIG. 9 is a graph showing the effect of the control method of a camera module according to an embodiment, and

[0033] FIG. 10 is a flowchart of a control method for a camera module according to an embodiment, and

[0034] FIG. 11 is a perspective view of a mobile terminal having a camera module applied according to an embodiment, and

[0035] FIG. 12 is a perspective view of a vehicle with a camera module applied according to an embodiment.

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0037] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0038] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0039] Furthermore, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0040] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0041] In addition, terms such as first, second, A, B, (a), (b), etc. may be used when describing the components of the embodiments of the present invention.

[0042] These terms are intended merely to distinguish a component from other components and are not limited by the essence, order, sequence, etc. of the component.

[0043] And, where it is stated that a component is 'connected', 'combined', or 'joined' to another component, this may include not only cases where the component is directly connected, combined, or joined to the other component, but also cases where it is 'connected', 'combined', or 'joined' due to another component located between the component and the other component.

[0044] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0045] FIG. 1 is a perspective view of a camera module according to an embodiment, FIG. 2 is an exploded perspective view of a camera module according to an embodiment, and FIG. 3 is a cross-sectional view of a camera module cut at AA' in FIG. 1.

[0046] Referring to FIGS. 1 and 2, a camera module (1000) according to an embodiment may consist of a cover (CV), a first camera actuator (1100), a second camera actuator (1200), and a circuit board (1300). Here, the first camera actuator (1100) may be used as the first actuator, and the second camera actuator (1200) may be used as the second actuator.

[0047] The cover (CV) can cover the first camera actuator (1100) and the second camera actuator (1200). The coupling force between the first camera actuator (1100) and the second camera actuator (1200) can be improved by the cover (CV).

[0048] Furthermore, the cover (CV) may be made of a material that performs electromagnetic shielding. Accordingly, the first camera actuator (1100) and the second camera actuator (1200) inside the cover (CV) can be easily protected.

[0049] And the first camera actuator (1100) may be an OIS (Optical Image Stabilizer) actuator. For example, the first camera actuator (1100) may move an optical member in a direction perpendicular to the optical axis.

[0050] The first camera actuator (1100) may include a fixed focal length lens disposed in a predetermined barrel (not shown). The fixed focal length lens may also be referred to as a “single focal length lens” or a “single lens.”

[0051] The first camera actuator (1100) can change the path of light. In an embodiment, the first camera actuator (1100) can change the path of light vertically through an internal optical element (e.g., a prism or a mirror). With this configuration, even if the thickness of the mobile terminal is reduced, a lens configuration larger than the thickness of the mobile terminal can be placed within the mobile terminal through the change of the path of light so that magnification, autofocus (AF), and OIS functions can be performed.

[0052] However, it is not limited to this, and the first camera actuator (1100) can change the light path multiple times vertically or at a predetermined angle.

[0053] The second camera actuator (1200) may be positioned at the rear end of the first camera actuator (1100). The second camera actuator (1200) may be coupled with the first camera actuator (1100). And the coupling between them may be achieved in various ways.

[0054] Additionally, the second camera actuator (1200) may be a zoom actuator or an AF (Auto Focus) actuator. For example, the second camera actuator (1200) may support one or more lenses and move the lenses according to a control signal from a predetermined control unit to perform an auto-focusing function or a zoom function. Also, one or more lenses may move independently or individually along the optical axis direction to perform AF.

[0055] A circuit board (1300) may be positioned at the rear end of a second camera actuator (1200). The circuit board (1300) may be electrically connected to the second camera actuator (1200) and the first camera actuator (1100). Additionally, there may be multiple circuit boards (1300). The circuit board (1300) may include an image sensor (IS) and may be fixed inside a camera module (1000). Additionally, the circuit board (1300) may be electrically connected to another sensor module within the terminal or to a processor of the terminal. Through this, the aforementioned camera actuator and the camera module including it can transmit and receive various signals within the terminal. The circuit board (1300) may include a circuit board having a wiring pattern that can be electrically connected, such as a rigid printed circuit board (Rigid PCB), a flexible printed circuit board (Flexible PCB), or a rigid-flexible printed circuit board (Rigid Flexible PCB). However, it is not limited to these types.

[0056] The camera module according to the embodiment may consist of a single or multiple camera modules. For example, the multiple camera modules may include a first camera module and a second camera module.

[0057] And the first camera module may include a single or multiple actuators. For example, the first camera module may include a first camera actuator (1100) and a second camera actuator (1200).

[0058] The second camera module may be disposed in a predetermined housing (not shown) and may include an actuator (not shown) capable of driving a lens portion. The actuator may be a voice coil motor, a micro actuator, a silicon actuator, etc., and may be applied in various ways such as electrostatic, thermal, bimorphic, and electrostatic force methods, but is not limited thereto. In addition, in this specification, the camera actuator may be referred to as an actuator, etc. Furthermore, a camera module composed of a plurality of camera modules may be mounted in various electronic devices such as mobile terminals.

[0059] Referring to FIG. 3, the camera module according to the embodiment may include a first camera actuator (1100) that performs an OIS function and a second camera actuator (1200) that performs a zooming function and an AF function.

[0060] Light can be incident into a camera module or the first camera actuator through an opening region located on the upper surface of the first camera actuator (1100). That is, light is incident into the interior of the first camera actuator (1100) along the optical axis direction (e.g., Z-axis direction), and the optical path can be changed in a vertical direction (e.g., Y-axis direction) through an optical member. Then, light passes through the second camera actuator (1200) and can be incident on an image sensor (IS) located at one end of the second camera actuator (1200) (PATH).

[0061] In this specification, the bottom surface refers to one side in the first direction. The first direction is the Z-axis direction in the drawing and may be used interchangeably with the first axis direction, etc. The second direction is the X-axis direction in the drawing and may be used interchangeably with the second axis direction, etc. The second direction is a direction perpendicular to the first direction. Additionally, the third direction is the Y-axis direction in the drawing and may be used interchangeably with the third axis direction, etc. The third direction is a direction perpendicular to both the first direction and the second direction. Here, the first direction (Z-axis direction) corresponds to the optical axis direction, and the second direction (X-axis direction) and the third direction (Y-axis direction) are directions perpendicular to the optical axis and may be tilted by the first camera actuator. The first direction is a direction perpendicular to the surface of the prism where light is incident, and the second direction may be a direction parallel to the surface of the prism where light is emitted. The third direction may be a direction perpendicular to the surface of the prism where light is emitted. In addition, in the description of the first camera actuator (1100) below, the optical axis direction is the first direction (Z-axis direction), and the description below is based on this.

[0062] Additionally, in this specification, the inner side may be the direction toward the first camera actuator from the cover (CV), and the outer side may be the opposite direction of the inner side. That is, the first camera actuator and the second camera actuator may be located on the inner side of the cover (CV), and the cover (CV) may be located on the outer side of the first camera actuator or the second camera actuator. Additionally, in this specification, the inner side may be the direction toward the first or second camera actuator from the bracket or shield can to be described later, and the outer side may be the opposite direction of the inner side.

[0063] And by this configuration, the camera module according to the embodiment can improve the spatial limitations of the first camera actuator and the second camera actuator by changing the light path. That is, the camera module according to the embodiment can expand the light path while minimizing the thickness of the camera module in response to the change in the light path. Furthermore, it should be understood that the second camera actuator can provide a high range of magnification by controlling focus, etc., in the expanded light path.

[0064] In addition, the camera module according to the embodiment can implement OIS by controlling the optical path through the first camera actuator, thereby minimizing the occurrence of decent or tilt phenomena and producing optimal optical characteristics.

[0065] Furthermore, the second camera actuator (1200) may include an optical system and a lens driving unit. For example, at least one of a first lens assembly, a second lens assembly, a third lens assembly, and a guide pin may be disposed in the second camera actuator (1200). Additionally, the second camera actuator (1200) may be equipped with a coil and a magnet to perform a high-magnification zooming function.

[0066] For example, the first lens assembly and the second lens assembly may be moving lenses that move via coils, magnets, and guide pins, and the third lens assembly may be a fixed lens, but is not limited thereto. For example, the third lens assembly may perform the function of a focuser that forms an image of light at a specific location, and the first lens assembly may perform the function of a variationator that re-forms the image formed by the third lens assembly (focuser) at a different location. Meanwhile, the first lens assembly may be in a state where the magnification changes significantly due to a large change in the distance to the subject or the image distance, and the first lens assembly (variator) may play an important role in the change of focal length or magnification of the optical system. On the other hand, the image formed by the first lens assembly (variator) may differ slightly depending on the location. Accordingly, the second lens assembly may perform a position compensation function for the image formed by the variationator. For example, the second lens assembly can perform the function of a compensator that accurately forms the image formed by the first lens assembly (which acts as a transducer) at the actual image sensor location. For example, the first lens assembly and the second lens assembly can be driven by electromagnetic force resulting from the interaction between a coil and a magnet. The above description may be applied to the lens assembly described below. Furthermore, the first to third lens assemblies can move along the optical axis direction, that is, the third direction. Additionally, the first to third lens assemblies can move in the third direction independently or dependently of each other.

[0067] Meanwhile, according to an embodiment of the present invention, when an actuator for OIS and an actuator for AF or Zoom are arranged, magnetic field interference with the magnet for AF or Zoom can be prevented during OIS operation. Since the first driving magnet of the first camera actuator (1100) is arranged separately from the second camera actuator (1200), magnetic field interference between the first camera actuator (1100) and the second camera actuator (1200) can be prevented. In this specification, OIS may be used interchangeably with terms such as hand shake correction, optical image stabilization, optical image correction, and shake correction.

[0068] FIG. 4 is a perspective view of a first camera actuator according to an embodiment, FIG. 5 is a cross-sectional view of the first camera actuator cut along BB' in FIG. 4, and FIG. 6 is a cross-sectional view of the first camera actuator cut along CC' in FIG. 4.

[0069] Referring to FIGS. 4 to 6, the first camera actuator (1100) may include a first housing (1110), a sub-housing (1120), a first lens module (1130), a mover (1140), a substrate part (1150), and a magnet part (1160).

[0070] The first housing (1110) may form the outer wall of the first camera actuator (1100). A sub-housing (1120), a mover (1140), and a magnet part (1160) may be disposed inside the first housing (1110). A substrate part (1150) may be disposed outside the first housing (1110). The first housing (1110) may include a shape in which the outer side is partially open to allow light to be incident or emitted.

[0071] A sub-housing (1120) may be disposed on a first housing (1110). The sub-housing (1120) may be coupled with the first housing (1110). The sub-housing (1120) may be disposed on one side of the first housing (1110). The sub-housing (1120) may come into contact with a mover (1140). A fourth magnet (1164) for securing the mover (1140) may be disposed on the sub-housing (1120). The sub-housing (1120) may include a ball seating portion (1121) on which a projection (1141) of the mover (1140) is disposed. The ball seating portion (1121) may include at least one inclined surface. The inclined surface of the ball seating portion (1121) may come into contact with the projection (1141).

[0072] The first lens module (1130) may be placed on the outside of the first housing (1110). The first lens module (1130) may be placed on the mover (1140). Light may enter the interior of the camera actuator (1100) through the first lens module (1130). The first lens module (1130) may include at least one lens. The optical axis direction of the lens of the first lens module (1130) may be formed in the first direction. Light may pass through the first lens module (1130) and enter the first prism (1142). The optical axis of at least one lens of the first lens module (1130) may pass through the center (1141a) of the hemisphere of the projection (1141). That is, the optical axis of at least one lens of the first lens module (1130) may overlap with the first axis (11).

[0073] A first prism (1142) may be placed in the mover (1140). The mover (1140) may rotate around a first axis (l1), a second axis (l2), or a third axis (l3) by contacting the sub-housing (1120). The mover (1140) may perform tilting of the first prism (1142) by rotating around the first axis (l1), the second axis (l2), or the third axis (l3). The mover (1140) may be placed inside the first housing (1110). The mover (1140) may be coupled with the first lens module (1130). The mover (1140) may include a receiving space in which the first prism (1142) is placed. The first to third magnets (1161, 1162, 1163) may be placed in the mover (1140).

[0074] The mover (1140) may include a projection (1141). The projection (1141) may be placed on the ball seating portion (1121) of the sub-housing (1120). The projection (1141) may form the center of the rotation axis of the mover (1140). The center of the hemisphere (1141a) of the projection (1141) may overlap with the intersection of the first axis (l1), the second axis (l2), and the third axis (l3). That is, the first axis (l1), the second axis (l2), and the third axis (l3) may all pass through the center of the hemisphere (1141a) of the projection (1141). The center of the hemisphere (1141a) of the projection (1141) may become the center of rotation of the mover (1140). Additionally, the center (1141a) of the hemisphere of the projection (1141) may overlap with the center of the reflective surface (1142b) of the prism (1142).

[0075] The mover (1140) may include a first member (1140a). The first member (1140a) may be coupled to the mover (1140). A fifth magnet (1165) may be disposed on the first member (1140a). The mover (1140) may be fixed to the sub-housing (1120) through the fifth magnet (1165) disposed on the first member (1140a) and the fourth magnet (1164) disposed on the sub-housing (1120).

[0076] The mover (1140) may include a first prism (1142). The first prism (1142) may reflect light. The first prism (1142) may reflect light incident from the outside and emit it. The first prism (1142) may include an incident surface (1142a) where light is incident, a reflective surface (1142b) that reflects light, and an exit surface (1142c) where light is emitted. The incident surface (1142a) of the first prism (1142) may be positioned perpendicular to the first direction. The exit surface (1142c) of the first prism (1142) may be positioned perpendicular to the third direction. The center of the reflective surface (1142b) of the first prism (1142) may overlap with the optical axis of the first prism (1142) and the optical axis of the reflected light of the first prism (1142). Additionally, the center of the reflective surface (1142b) of the first prism (1142) may overlap with the intersection of the first axis (l1), the second axis (l2), and the third axis (l3).

[0077] The substrate portion (1150) can supply power required for driving the first camera actuator (1100). The substrate portion (1150) may be placed on the outside of the first housing (1110). The substrate portion (1150) may include a coil portion (C1, C2, C3), a Hall sensor, and a driver IC. The coil portion may include a first coil (C1), a second coil (C2), and a third coil (C3). The first to third coils (C1, C2, C3) can each apply electromagnetic force to the first to third magnets (1161, 1162, 1163) to perform OIS driving.

[0078] The magnet part (1160) can tilt the mover (1140) through interaction with the first to third coils (C1, C2, C3). Additionally, the magnet part (1160) can fix the mover (1140). The magnet part (1160) may include at least one magnet and at least one magnet yoke. The magnet part (1160) may include a driving magnet and a fixed magnet. The magnet part (1160) may include first to fifth magnets (1161, 1162, 1163, 1164, 1165). The first to third magnets (1161, 1162, 1163) may be driving magnets. The first to third magnets (1161, 1162, 1163) may be placed on the mover (1140). The fourth magnet (1164) and the fifth magnet (1165) may be fixed magnets. The fourth magnet (1164) and the fifth magnet (1165) may fix the mover (1140) through interaction with each other. The fourth magnet (1164) may be placed in the sub-housing (1120), and the fifth magnet (1165) may be placed in the first member (1140a).

[0079] The coil portion (C1, C2, C3), Hall sensor, and magnet portion (1160) of the substrate portion (1150) may correspond to a driving portion that drives the mover (1140) of the first camera actuator (1100). Additionally, the driver IC of the substrate portion (1150) may correspond to a control portion that controls the driving portion. The driver IC may include a memory for storing data. For example, the memory of the driver IC may store rotation angle data of the first prism (1142) measured by the Hall sensor.

[0080] The first camera actuator (1100) of the camera module can perform OIS driving through a control unit and a sensor.

[0081] The camera module may include a gyro sensor and a Hall sensor.

[0082] First, the gyro sensor can measure the angular velocity of the camera module in real time, which is caused by external factors such as user hand tremors or vehicle vibrations. The gyro sensor may be placed on the inside or outside of the first camera actuator. For example, the gyro sensor may be placed on the circuit board of the camera module or on a separate board other than the circuit board. Additionally, the gyro sensor may be placed at a different location within the terminal other than the camera module. The measured angular velocity information is transmitted to the control unit and used as basic data for correcting image shake. The control unit analyzes the hand tremors input from the gyro sensor to calculate the angle at which the first prism (1142) should be tilted, and transmits the corresponding correction command to the driving unit of the first camera actuator. The gyro sensor may be placed on the outside of the first camera actuator. In this way, the gyro sensor acts as a pre-input that quickly detects external movements, enabling the OIS system to perform correction operations without delay. Specifically, the gyroscope sensor can measure the angular velocity per second of the camera module. The gyroscope sensor can calculate the actual rotation angle through the angular velocity per second of the camera module.

[0083] A Hall sensor is provided inside the first camera actuator to detect the tilt position of the first prism (1142). The Hall sensor may be placed on the substrate portion (1150) of the first camera actuator. The Hall sensor is placed inside the first camera actuator together with a magnet portion (1160), and the position of the magnet portion (1160) changes as the first prism (1142) tilts. By detecting this change in magnetic flux and converting it into an electrical signal, the Hall sensor can precisely calculate the current tilt angle of the first prism (1142). Through this, the control unit checks in real time whether the prism has accurately reached the target position, and if a difference occurs between the target value and the actual value, it corrects the driving signal to reduce the error. In other words, the Hall sensor is a key feedback sensor that enables closed-loop control of the actuator and provides high-resolution position detection capabilities capable of detecting even minute changes in angle.

[0084] The control unit may include an interface unit, a computation unit, a conversion unit, and a drive control unit. The interface unit can receive angular velocity data of the camera module from the gyroscope sensor. That is, the interface unit can receive control commands necessary for the operation of the control unit. The computation unit can perform a correction operation using the angular velocity information provided by the gyroscope sensor and the actual rotation angle information of the first prism (1142) detected by the Hall sensor. The computation unit can calculate the error between the target rotation angle and the actual rotation angle and apply a control algorithm to minimize this error. In particular, a correction algorithm to correct non-linear characteristics occurring in the prism tilting method can be performed, thereby allowing pixel movement on the image sensor (IS) to appear linearly. The conversion unit processes the output signal of the Hall sensor to enable the computation unit to use it stably. The Hall sensor detects the actual tilt of the first prism (1142), and the conversion unit can convert this analog signal into digital data and perform noise removal and temperature correction if necessary. Through this, the conversion unit secures accurate position information in real time, enabling precise closed-loop control.

[0085] The control unit can adjust the optical axis by tilting the mover (1140) and the first prism (1142) with respect to the rotation axis. For example, if hand shaking occurs in the hand holding the camera module, the gyro sensor can detect such shaking, and the calculation unit of the control unit can calculate the control amount of the mover (1140) and the first prism (1142) according to the degree of shaking detected and correct it in the opposite direction of the shaking. The control unit can control the drive unit based on the rotation angle of the first prism (1142) detected through the Hall sensor.

[0086] The control unit can change the angle of the optical axis of the mover (1140) and the first prism (1142) placed on the mover (1140) by rotating the mover (1140). The control unit can rotate the first prism (1142) by a certain angle. The control unit can rotate the first prism (1142) by a certain angle around a first direction, a second direction, or a third direction. For example, the control unit can rotate the first prism (1142) by a first angle around the second direction. If the Hall sensor senses that the first prism (1142) is misaligned by a first angle around the second direction, the control unit can correct hand tremor by controlling the first prism (1142) to rotate by a first angle in the opposite direction.

[0087] The control unit can control the actuator according to a unit code. The control unit can calculate the unit code using angular velocity information input from a gyroscope sensor. The unit code may refer to the minimum unit of a control signal generated by the control unit to control the actuator's actuator. The unit code can produce a minimum increment corresponding to actuator driving, such as, for example, the unit of a digital control command or the reference voltage unit of an analog control signal. The control unit can convert a hand shake correction command input from an external processor into a unit code unit according to internal control logic and apply a current or voltage corresponding to the unit code to the actuator.

[0088] Figure 7 is a graph showing the overshoot phenomenon according to the control method of a conventional camera module.

[0089] Referring to FIG. 7, an overshoot phenomenon may occur according to the control method of a conventional camera module. FIG. 7 is a graph showing the rotation angle (°) of the first prism according to time (t). The control unit of the camera actuator can set a target rotation angle. The control unit sets a control amount according to the magnitude of the target rotation angle, and the prism can rotate according to the control amount. As the target rotation angle increases, the control amount may increase. As the control amount of the control unit increases, the control force applied by the driving unit to the mover increases. Accordingly, an overshoot phenomenon may occur in which the mover and the prism rotate to an angle greater than the target rotation angle and then return to the target rotation angle. When the overshoot phenomenon occurs, a stabilization time is required to reach the target rotation angle (Area A), which may be disadvantageous in terms of control time. That is, the time required to reach the settling time (Area B) may increase. In addition, if the overshoot phenomenon occurs beyond a certain level, it may reach the mechanical limit (Mecha), which can be disadvantageous in terms of stability.

[0090] FIG. 8 is a graph for explaining a control method of a camera module according to an embodiment.

[0091] Referring to FIG. 8, the control unit of the camera module according to the embodiment can control the driving unit according to a plurality of control cycles. FIG. 8 is a graph showing the rotation angle of the first prism over time. The control unit of the first camera actuator can control the driving unit according to a constant control cycle. That is, the control unit can rotate the first prism by controlling the driving unit at time intervals corresponding to the control cycle.

[0092] The control unit can set a target rotation angle (D) based on the detection result of the gyro sensor. The target rotation angle (D) may represent the angle at which the camera actuator ultimately rotates the first prism to correct hand shake. The control unit can calculate the target rotation angle (D) by analyzing hand shake information input from the gyro sensor and calculating the angle at which the first prism (1142) should be tilted. The calculation of the target rotation angle (D) can be performed in the operation unit of the control unit. The gyro sensor can detect the rotation of the first prism when hand shake occurs, and the control unit can calculate the target rotation angle (D) of the first prism to correct hand shake through the detection result of the gyro sensor.

[0093] The control unit can set a target control amount corresponding to a target rotation angle (D). The control unit can set a target control amount to control the drive unit in order to rotate the first prism to the target rotation angle (D). Ultimately, the target control amount can be proportional to the target rotation angle (D). The control amount of the control unit may refer to a code value that controls the drive unit. The calculation unit of the control unit can calculate the target control amount corresponding to the target rotation angle (D) and transmit a drive command to the drive unit according to the target control amount. Additionally, the control unit can control the drive unit for a total control time (T) to reach the target rotation angle (D).

[0094] The control unit can control the drive unit to drive the first prism to a target rotation angle (D) over a plurality of stages. The control unit can control the drive unit according to a plurality of control cycles during a total control time (T). The control unit can perform control of the drive unit for each of the plurality of control cycles. The sum of the plurality of control cycles may correspond to the total control time (T). The target rotation angle of the first prism corresponding to each of the plurality of control cycles may be different. For example, as the plurality of control cycles progress, the target rotation angle of the first prism may increase. Each of the plurality of control cycles may be a stage for rotating the first prism to the target rotation angle (D). The sum of the control amount of the control unit corresponding to each of the plurality of control cycles may be equal to the target control amount of the control unit. The control unit can adjust the size (t) of the control cycle. The control unit can increase or decrease the size of the control cycle. If the control unit increases the size of the control cycle, the time interval of each control cycle may increase, and if the control unit decreases the size of the control cycle, the time interval of each control cycle may decrease. The sizes (t) of multiple control cycles may be the same or different from each other. However, the total control time (T) may be constant in both cases where the sizes (t) of multiple control cycles are the same and where they are different. When the sizes (t) of multiple control cycles are different from each other, the size of the control quantity corresponding to each control cycle may be different. Also, when the sizes (t) of multiple control cycles are the same from each other, the size of the control quantity corresponding to each control cycle may be the same. For example, when the sizes (t) of multiple control cycles are the same from each other, if the control unit sets the target control quantity to 1000 codes and sets the size of the control quantity corresponding to each control cycle to 10 codes, the control of the driving unit may be performed over a total of 10 control cycles.

[0095] In each control cycle, the driving unit can rotate the mover and the first prism by a first unit angle (d). That is, the control unit can rotate the first prism by a certain angle in each control cycle. The sum of the first unit angles (d) in multiple control cycles may correspond to a target rotation angle (D). The control unit can adjust the size of the first unit angle (d). The control unit can increase or decrease the size of the first unit angle (d). If the size of the first unit angle (d) increases, the range of the rotation angle of the first prism in each control cycle may increase. If the size of the first unit angle (d) decreases, the range of the rotation angle of the first prism in each control cycle may decrease. The control unit can adjust the control cycle or the size of the first unit angle independently or simultaneously.

[0096] Multiple control cycles may include a first control cycle to a tenth control cycle (t1 to t10). The first control cycle to the tenth control cycle (t1 to t10) may proceed sequentially until the first prism reaches a target rotation angle (D). That is, the control unit may sequentially control the drive unit from the first control cycle (t1) to the tenth control cycle (t10). Each of the first control cycle to the tenth control cycle (t1 to t10) may proceed for a certain period of time. After the tenth control cycle (t10) has proceeded, the first prism may be rotated to the target rotation angle (D). The first control cycle (t1) may proceed after the control of the control unit has started, and the state in which the first control cycle (t1) has proceeded may correspond to the first step (Step 1). In addition, the state in which the second control cycle (t2) proceeds in the first step (Step 1) may correspond to the second step (Step 2). The control unit can control the driving unit over a total of 10 steps, from the first step to the tenth step. That is, the control unit can perform control of the driving unit over a plurality of steps. Although the case in which the plurality of control cycles according to the embodiment include 10 control cycles has been described, it is not limited thereto.

[0097] The target rotation angle (D) may include a first target rotation angle to a tenth target rotation angle (d1 to d10) corresponding to each of the first to tenth control cycles (t1 to t10). The first to tenth target rotation angles (d1 to d10) may each be a target rotation angle in the first to tenth control cycles (t1 to t10). That is, for example, the first target rotation angle (d1) may correspond to the rotation angle of the mover and the first prism in the first step (Step 1) after the first control cycle (t1) has ended. The tenth target rotation angle (d10) may correspond to the rotation angle of the mover and the first prism after the tenth control cycle (t10) has ended. Accordingly, the tenth target rotation angle (d10) may be the same as the target rotation angle (D).

[0098] The drive unit can rotate the mover to a first target rotation angle (d1) and then, after a certain time interval, rotate it to a second target rotation angle (d2) which is greater than the first target rotation angle (d1). The second target rotation angle (d2) in the second control cycle (t2) may be greater than the first target rotation angle (d1) in the first control cycle (t1). Therefore, as multiple control cycles progress, the target rotation angle of the camera actuator can gradually increase. Accordingly, the overshoot phenomenon during OIS driving of the camera actuator can be prevented, and the stabilization time can be reached quickly.

[0099] FIG. 9 is a graph showing the effect of the control method of a camera module according to an embodiment.

[0100] Referring to FIG. 9, the control method of the camera module according to the embodiment can prevent an overshoot phenomenon during the OIS control process. FIG. 9 is a graph showing the rotation angle (°) of the prism according to time (t). According to the control method of the camera module according to the embodiment, the rotation angle of the first prism can gradually increase from the time the control unit begins to perform control until it reaches the target rotation angle (Target) (Stage A). Even if the rotation angle of the first prism reaches the target rotation angle (Target), it can maintain the target rotation angle (Target) without exceeding it. Accordingly, the time required to reach the stabilization time (Stage B) can be reduced. Therefore, according to the camera module and control method according to the embodiment, the overshoot phenomenon during OIS driving can be prevented, and collisions with mechanical components caused by mechanical limits can be prevented. In addition, the stability and speed of OIS driving can be improved, and it can also be effective in terms of the suppression ratio of OIS driving.

[0101] FIG. 10 is a flowchart of a camera module control method according to an embodiment.

[0102] Referring to FIG. 10, a camera module control method (S1000) according to an embodiment may include a step of setting a control amount (S1100), a step of setting a control cycle (S1200), a step of controlling a driving unit (S1300), and a step of rotating a prism (S1400).

[0103] In the step of setting the control amount (S1100), the control unit may set a target control amount and a unit control amount obtained by dividing the target control amount. The target control amount of the control unit may refer to the control amount required for the control unit to control the driving unit to rotate the first prism by a target rotation angle during OIS driving. The unit control amount of the control unit may refer to the control amount of each stage divided to control the target control amount according to a plurality of stages. Additionally, the camera module control method may include a step in which the control unit adjusts the size of the unit control amount.

[0104] In the step of setting the control cycle (S1200), the control unit may set a control cycle corresponding to a unit control amount. The control cycle of the control unit may refer to the time required to control the driving unit by the unit control amount at each step. The sum of the control cycles of each step may correspond to the total control time. Additionally, the camera module control method may include a step in which the control unit adjusts the size of the control cycle.

[0105] In the step (S1300) of controlling the drive unit, the control unit can control the drive unit according to the unit control amount and the control cycle. The control unit can control the drive unit according to the set unit control amount and the control cycle. At this time, the control unit can control the drive unit multiple times in stages for each unit control amount and control cycle.

[0106] In the step of rotating the prism (S1400), the driving unit can rotate the mover and the first prism according to the control of the control unit. The driving unit can rotate the mover and the first prism according to the control of the control unit in each control cycle. After the driving unit rotates the mover and the first prism, the Hall sensor can sense the rotation of the mover and the first prism.

[0107] FIG. 11 is a perspective view of a mobile terminal with a camera module applied according to an embodiment.

[0108] Referring to FIG. 11, the mobile terminal of the embodiment may include a camera module (1000), a flash module (1510), and an autofocus device (1530) provided on the rear.

[0109] The camera module (1000) may include an image capturing function and an autofocus function. For example, the camera module (1000) may include an autofocus function using an image.

[0110] The camera module (1000) processes still image or video frame obtained by the image sensor in shooting mode or video call mode.

[0111] The processed image frame may be displayed on a designated display unit and stored in memory. A camera (not shown) may also be placed on the front of the mobile terminal body.

[0112] For example, the camera module (1000) may include a first camera module and a second camera module, and the first camera module may enable the implementation of AF or zoom functions along with OIS. Additionally, AF, zoom, and OIS functions may be performed by the second camera module. In this case, since the first camera module includes both the OIS actuator and the camera actuator described above, the camera module can be easily miniaturized by changing the light path.

[0113] The flash module (1510) may include a light-emitting element that emits light inside. The flash module (1510) may be operated by the operation of the camera of the mobile terminal or by the control of the user.

[0114] The autofocus device (1530) may include one of the packages of surface light-emitting laser elements as a light-emitting part.

[0115] The autofocus device (1530) may include an autofocus function using a laser. The autofocus device (1530) may be mainly used in conditions where the autofocus function using the image of the camera module (1000) is degraded, such as in a close distance of 10m or less or in a dark environment.

[0116] The autofocus device (1530) may include a light-emitting part comprising a vertical cavity surface-emitting laser (VCSEL) semiconductor device and a light-receiving part that converts light energy into electrical energy, such as a photodiode.

[0117] FIG. 12 is a perspective view of a vehicle with a camera module applied according to an embodiment.

[0118] For example, FIG. 12 is an exterior view of a vehicle equipped with a vehicle driving assistance device having a camera module according to an embodiment.

[0119] Referring to FIG. 12, the vehicle (700) of the embodiment may be equipped with wheels (13FL, 13FR) that rotate by a power source and a predetermined sensor. The sensor may be a camera sensor (3000), but is not limited thereto.

[0120] The camera sensor (3000) may be a camera sensor to which a camera module according to the embodiment is applied. The vehicle (700) of the embodiment can acquire image information through the camera sensor (3000) that captures a front image or a surrounding image, and can determine a situation where a lane is not identified using the image information and generate a virtual lane when it is not identified.

[0121] For example, a camera sensor (3000) captures the front of a vehicle (700) to obtain a front image, and a processor (not shown) can obtain image information by analyzing objects included in the front image.

[0122] For example, if objects such as a median strip, curb, or roadside tree corresponding to a lane, adjacent vehicle, driving obstruction, and indirect road marking are captured in an image captured by the camera sensor (3000), the processor can detect these objects and include them in the image information. At this time, the processor can obtain distance information with respect to the objects detected through the camera sensor (3000) to further supplement the image information.

[0123] The image information may be information about an object captured in the image. Such a camera sensor (3000) may include an image sensor and an image processing module.

[0124] The camera sensor (3000) can process still images or videos obtained by an image sensor (e.g., CMOS or CCD).

[0125] The image processing module can process still images or videos acquired through an image sensor to extract necessary information and transmit the extracted information to a processor.

[0126] At this time, the camera sensor (3000) may include a stereo camera to improve the measurement accuracy of the object and to obtain more information such as the distance between the vehicle (700) and the object, but is not limited thereto.

[0127] Although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. A first camera actuator that reflects incident light; A second camera actuator that passes light reflected from the first camera actuator; and It includes an image sensor that receives light passing through the second camera actuator, and The first camera actuator comprises a mover, a first prism disposed on the mover, a driving unit for driving the first prism, and a control unit for controlling the driving unit. The above control unit controls the driving unit by setting the target rotation angle of the first prism, and The above control unit is a camera module that controls the driving unit to drive the first prism to the target rotation angle over a plurality of steps of different rotation angles.

2. In Paragraph 1, The above control unit controls the driving unit according to a plurality of control cycles, and A camera module in which the target rotation angle of the first prism corresponding to each of the plurality of control cycles is different.

3. In Paragraph 2, The sizes of the above plurality of control cycles are the same or different from each other, and The above plurality of control cycles is a camera module including a first control cycle to a tenth control cycle.

4. In Paragraph 3, A camera module comprising a first target rotation angle to a tenth target rotation angle corresponding to each of the first to tenth control cycles.

5. In Paragraph 4, The above driving unit is a camera module that rotates the mover to the first target rotation angle and then, after a certain time interval, rotates it to the second target rotation angle which is greater than the first target rotation angle.

6. In Paragraph 1, A camera module in which the sum of the control amounts of the control unit corresponding to each of the plurality of control cycles is equal to the target control amount of the control unit.

7. In Paragraph 3, The sizes of the above plurality of control cycles are identical to each other, and In each control cycle, the driving unit is a camera module that rotates the first prism by a first unit angle.

8. In Paragraph 7, The above control unit is a camera module that adjusts the size of the first unit angle.

9. In Paragraph 8, The above control unit is a camera module that adjusts the size of the control cycle.

10. A step in which the control unit sets a target control amount and a unit control amount obtained by dividing the target control amount; A step in which the control unit sets a control cycle corresponding to the unit control amount; The step of the control unit controlling the driving unit according to the unit control amount and the control cycle; and A camera module control method comprising the step of the above driving unit rotating a mover and a first prism according to the control of the above control unit.

Images