Patent Publication Number: US-2023152669-A1

Title: Optical element driving mechanism with different control modes

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of pending U.S. patent application Ser. No. 16/938,264, filed Jul. 24, 2020 and entitled “OPTICAL ELEMENT DRIVING MECHANISM WITH DIFFERENT CONTROL MODES ”, which claims the benefit of U.S. Provisional Application No. 62/879,190, filed on Jul. 26, 2019, the entirety of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to an optical element driving mechanism with different control modes. 
     Description of the Related Art 
     As technology has developed, it has become more common to include image-capturing and video-recording functions into many types of modern electronic devices, such as smartphones and digital cameras. These electronic devices are used more and more often, and new models have been developed that are convenient, thin, and lightweight, offering more choice to consumers. 
     Electronic devices that have image-capturing or video-recording functions normally include a driving mechanism to drive an optical element (such as a lens) to move along its optical axis, thereby achieving auto focus (AF) or optical image stabilization (OIS). Light may pass through the optical element and may form an image on an optical sensor. However, the trend in modern mobile devices is to have a smaller size and more durability. As a result, how to effectively reduce the size of the driving mechanism and how to increase its durability have become important issues. 
     BRIEF SUMMARY OF DISCLOSURE 
     A driving mechanism is provided. The driving mechanism includes a fixed portion, a movable portion, and a driving assembly. The movable portion is movably connected to the fixed portion. The driving assembly is used for driving the movable portion to move relative to the fixed portion. The driving assembly is driven by a control signal provided by a control assembly. The driving assembly includes a shape memory alloy. 
     In some embodiments, the movable portion is used for connecting to an optical assembly having a main axis, and the movable portion is positioned in the accommodation space of the fixed portion. The driving mechanism further includes a position sensing assembly for detecting the movement of the movable portion relative to the fixed portion, and the control assembly receives a position signal provided by the position sensing assembly. The position signal includes a first position signal and a second position signal. The position sensing assembly includes a first position sensor, a second position sensor, a first reference element, and a second reference element. The first position sensor is used for detecting the movement of the movable portion relative to the fixed portion in a first dimension, and used for providing the first position signal. The second position sensor is used for detecting the movement of the movable portion relative to the fixed portion in a second dimension, and used for providing the second position signal. The first reference element corresponds to the first position sensor, and the first reference element includes a first magnetic unit. The second reference element corresponds to the second position sensor, the second reference element includes a second magnetic unit, and the position sensing assembly is at least partially positioned in the accommodation space. 
     In some embodiments, the driving assembly includes a first driving element and a second driving element. The first driving element is used for driving the movable portion to move relative to the fixed portion, and the first driving element includes a first driving unit and a second driving unit. The first driving unit is used for driving the movable portion to move relative to the fixed portion, the material of the first driving unit includes shape memory alloy, and the first driving unit is strip-shaped and extends in a first direction. The second driving unit is used for driving the movable portion to move relative to the fixed portion, the material of the second driving unit includes shape memory alloy, and the second driving unit is strip-shaped and extends in a second direction. The second driving unit is used for driving the movable portion to move relative to the fixed portion, and the second driving element includes a third driving unit and a fourth driving unit. The third driving unit is used for driving the movable portion to move relative to the fixed portion, the material of the third driving unit includes shape memory alloy, and the third driving unit is strip-shaped and extends in a third direction. The fourth driving unit is used for driving the movable portion to move relative to the fixed portion, the material of the fourth driving unit includes shape memory alloy, and the fourth driving unit is strip-shaped and extends in a fourth direction. The first direction is different than the third direction, the second direction is different than the third direction, the first direction is substantially parallel to the second direction, and the third direction is substantially parallel to the fourth direction. The movable portion vibrates relative to the fixed portion at a frequency that is lower than the maximum frequency, and the control signal includes a first driving signal provided to the first driving unit, a second driving signal provided to the second driving unit, a third driving signal provided to the third driving unit, and a fourth driving signal provided to the fourth driving unit. The first driving signal, the second driving signal, the third driving signal, and the fourth driving signal do not include a periodic signal with a frequency higher than 10000 Hz. After the control assembly receives an environmental signal provided by an environmental sensing assembly, the control signal is provided to the driving assembly by the control assembly, and the control assembly removes the high-frequency signal from the environmental signal after the control assembly receives the environmental signal. The environmental sensing assembly is used for detecting the influence of the environment on the driving mechanism, and the environmental sensing assembly includes an inertia sensing element. 
     In some embodiments, the first driving element is used for driving the movable portion to move relative to the fixed portion along the first dimension, the second driving element is used for driving the movable portion to move relative to the fixed portion along the second dimension. The first driving signal, the second driving signal, the third driving signal, and the fourth driving signal do not include periodic signal having a frequency higher than the maximum frequency. The control assembly removes a portion of the environmental signal that has a frequency higher than 10000 Hz after the control assembly receives the environmental signal. The control assembly controls the driving assembly according to a preparation mode, a first control mode, a second control mode, a third control mode, or a fourth control mode. During the preparation mode, the control assembly drives the driving assembly according to the position signal to position the movable portion at a predetermined position relative to the fixed portion. During the preparation mode, the first driving signal does not include a periodic signal with a frequency higher than 10000 Hz. During the preparation mode, the control signal does not include a periodic signal with a frequency higher than 10000 Hz. During the preparation mode, the first driving signal has a voltage or a current higher than 0 at any time. During the preparation mode, the second driving signal has a voltage or a current higher than 0 at any time. During the first control mode, the control assembly controls the driving assembly to drive the movable portion to move relative to the fixed portion in a first target direction. During the first control mode, the control assembly controls the driving assembly according to the first position signal. During the first control mode, the first driving signal has a voltage or a current higher than 0 at any time. During the first control mode, the second driving signal has a voltage or a current higher than 0 at any time. During the first control mode, the first driving signal does not include a periodic signal with a frequency higher than 10000 Hz. During the first control mode, the control signal does not include a periodic signal with a frequency higher than 10000 Hz. During the first control mode, the voltage or the current of the first driving signal is higher than the voltage or the current of the second driving signal. During the first control mode, the control assembly increases the voltage or the current of the first driving signal. During the first control mode, the control assembly decreases the voltage or the current of the second driving signal. During the first control mode, the control assembly increases the voltage or the current of the third driving signal. During the first control mode, the control assembly increases the voltage or the current of the fourth driving signal. During the second control mode, the control assembly controls the driving assembly to drive the movable portion to move relative to the fixed portion in a second target direction. During the second control mode, the control assembly controls the driving assembly according to the first position signal. During the second control mode, the first driving signal has a voltage or a current higher than 0 at any time. During the second control mode, the second driving signal has a voltage or a current higher than 0 at any time. During the second control mode, the first driving signal does not include a periodic signal with a frequency higher than 10000 Hz. During the second control mode, the control signal does not include a periodic signal with a frequency higher than 10000 Hz. During the second control mode, the control assembly increases the voltage or the current of the first driving signal. During the second control mode, the control assembly increases the voltage or the current of the second driving signal. During the second control mode, the control assembly decreases the voltage or the current of the third driving signal. During the second control mode, the control assembly decreases the voltage or the current of the fourth driving signal. During the third control mode, the control assembly controls the driving assembly according to the environmental signal. During the third control mode, the first driving signal has a voltage or a current higher than 0 at any time. During the third control mode, the second driving signal has a voltage or a current higher than 0 at any time. During the third control mode, the first driving signal does not include a periodic signal with a frequency higher than 10000 Hz. During the third control mode, the control signal does not include a periodic signal with a frequency higher than 10000 Hz. During the third control mode, the voltage or the current of the first driving signal is higher than the voltage or the current of the second driving signal. During the third control mode, the control assembly increases the voltage or the current of the first driving signal. During the third control mode, the control assembly decreases the voltage or the current of the second driving signal. During the third control mode, the control assembly decreases the voltage or the current of the third driving signal. During the third control mode, the control assembly decreases the voltage or the current of the fourth driving signal. During the fourth control mode, the control assembly controls the driving assembly according to the environmental signal. During the fourth control mode, the first driving signal has a voltage or a current higher than 0 at any time. During the fourth control mode, the second driving signal has a voltage or a current higher than 0 at any time. During the fourth control mode, the first driving signal does not include a periodic signal with a frequency higher than 10000 Hz. During the fourth control mode, the control signal does not include a periodic signal with a frequency higher than 10000 Hz. During the fourth control mode, the control assembly increases the voltage or the current of the first driving signal. During the fourth control mode, the control assembly increases the voltage or the current of the second driving signal. During the fourth control mode, the control assembly decreases the voltage or the current of the third driving signal. During the fourth control mode, the control assembly decreases the voltage or the current of the fourth driving signal. 
     In some embodiments, after the control assembly receives the environmental signal, the portion of the environmental signal that has a frequency higher than the maximum frequency is removed. The inertia sensing element includes an accelerometer or a gyroscope. During the preparation mode, the control assembly drives the first driving element according to the first position signal to position the movable portion at the predetermined position relative to the fixed portion. During the preparation mode, the control assembly drives the second driving element according to the second position signal to position the movable portion at the predetermined position relative to the fixed portion. During the preparation mode, the control signal does not include a periodic signal with a frequency higher than the maximum frequency. During the preparation mode, the first driving signal does not include a periodic signal with a frequency higher than the maximum frequency. During the first control mode, the control signal does not include a periodic signal with a frequency higher than the maximum frequency. During the first control mode, the first driving signal does not include a periodic signal with a frequency higher than the maximum frequency. During the first control mode, the absolute value of the voltage or the current of the first driving signal increased by the control assembly is different than the absolute value of the voltage or the current of the third driving signal increased by the control assembly. During the second control mode, the control signal does not include a periodic signal with a frequency higher than the maximum frequency. During the second control mode, the first driving signal does not include a periodic signal with a frequency higher than the maximum frequency. During the third control mode, the control assembly further controls the driving assembly according to the position signal. During the third control mode, the control signal does not include a periodic signal with a frequency higher than the maximum frequency. During the third control mode, the first driving signal does not include a periodic signal with a frequency higher than the maximum frequency. During the fourth control mode, the control assembly further controls the driving assembly according to the position signal. During the fourth control mode, the control signal does not include a periodic signal with a frequency higher than the maximum frequency. During the fourth control mode, the first driving signal does not include a periodic signal with a frequency higher than the maximum frequency. 
     In some embodiments, during the preparation mode, the control signal only includes DC voltage or DC current. During the preparation mode, the first driving signal only includes DC voltage or DC current. During the first control mode, the control signal only includes DC voltage or DC current. During the first control mode, the first driving signal only includes DC voltage or DC current. During the first control mode, the absolute value of the voltage or the current of the first driving signal increased by the control assembly is higher than the absolute value of the voltage or the current of the third driving signal increased by the control assembly. During the first control mode, the absolute value of the voltage or the current of the first driving signal increased by the control assembly is higher than the absolute value of the voltage or the current of the fourth driving signal increased by the control assembly. During the second control mode, the control signal only includes DC voltage or DC current. During the second control mode, the first driving signal only includes DC voltage or DC current. During the third control mode, the first driving signal only includes DC voltage or DC current. During the third control mode, the control signal only includes a periodic signal with a frequency that is identical to the frequency of the environmental signal. During the fourth control mode, the first driving signal only includes DC voltage or DC current. During the fourth control mode, the control signal only includes a periodic signal with a frequency that is identical to the frequency of the environmental signal. 
     In some embodiments, during the third control mode, the control signal only includes DC voltage or DC current. During the fourth control mode, the control signal only includes DC voltage or DC current. The optical assembly further includes: an inner fixed portion having a polygonal structure when viewed along the main axis, an inner movable portion used for connecting the optical element, and an inner driving assembly used for driving the inner movable portion to move relative to the inner fixed portion. 
     In some embodiments, the inner driving assembly is positioned at a first corner of the inner fixed portion. The first position sensor is positioned at a first side of the inner fixed portion or the first corner of the inner fixed portion, when the first position sensor is positioned at the first corner, and the inner driving assembly at least partially overlaps the first position sensor when viewed along the main axis. The control assembly is positioned outside the accommodation space, and the position sensing assembly is at least partially positioned outside the accommodation space. 
     In some embodiments, the inner driving assembly is positioned at a first side of the inner fixed portion. The first position sensor is positioned at a first corner of the inner fixed portion or the first side of the inner fixed portion, when the first position sensor is positioned at the first side, the inner driving assembly at least partially overlaps the first position sensor when viewed along the main axis. The control assembly and the first position sensor are formed as one piece. 
     In some embodiments, the inner driving assembly is positioned at a first side of the inner fixed portion or a first corner of the inner fixed portion. The first position sensor is positioned at a second side of the inner fixed portion or a second corner of the inner fixed portion, and the inner driving assembly does not overlap the first position sensor when viewed along the main axis. The entire position sensing assembly is positioned in the accommodation space. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It should be noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    is a schematic view of a driving mechanism in some embodiments of the present disclosure. 
         FIG.  2    is a top view of the base, the movable portion, and the driving assembly. 
         FIG.  3    is a top view of some elements of the optical assembly. 
         FIG.  4    is a block diagram showing the connection of some elements of the driving mechanism. 
         FIG.  5    is a schematic view of the control signal of the control assembly under a preparation mode. 
         FIG.  6 A  is a schematic view of the control signal of the control assembly under a first control mode. 
         FIG.  6 B  is a schematic view showing the tension differences of the first driving unit, the second driving unit, the third driving unit, and the fourth driving unit between the first control mode and the preparation mode in  FIG.  5     
         FIG.  7 A  is a schematic view of the control signal of the control assembly under a second control mode. 
         FIG.  7 B  is a schematic view showing the tension differences of the first driving unit, the second driving unit, the third driving unit, and the fourth driving unit between the second control mode and the preparation mode in  FIG.  5     
         FIG.  8 A  is a schematic view of the control signal of the control assembly under a third control mode. 
         FIG.  8 B  is a schematic view showing the tension differences of the first driving unit, the second driving unit, the third driving unit, and the fourth driving unit between the third control mode and the preparation mode in  FIG.  5   . 
         FIG.  9 A  is a schematic view of the optical assembly in some embodiments of the present disclosure. 
         FIG.  9 B  is a top view of some elements of the optical assembly. 
         FIG.  10 A  is a schematic view of the optical assembly in some embodiments of the present disclosure. 
         FIG.  10 B  is a top view of some elements of the optical assembly. 
         FIG.  11 A  is a schematic view of the optical assembly in some embodiments of the present disclosure. 
         FIG.  11 B  is a top view of some elements of the optical assembly. 
         FIG.  12    is a top view of some elements of the optical assembly in some embodiments of the present disclosure. 
         FIG.  13    is a top view of some elements of the optical assembly in some embodiments of the present disclosure. 
         FIG.  14    is a top view of some elements of the optical assembly in some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSURE 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are in direct contact, and may also include embodiments in which additional features may be disposed between the first and second features, such that the first and second features may not be in direct contact. 
     In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a feature on, connected to, and/or coupled to another feature in the present disclosure that follows may include embodiments in which the features are in direct contact, and may also include embodiments in which additional features may be disposed interposing the features, such that the features may not be in direct contact. In addition, spatially relative terms, for example, “vertical,” “above,” “over,” “below,”, “bottom,” etc. as well as derivatives thereof (e.g., “downwardly,” “upwardly,” etc.) are used in the present disclosure for ease of description of one feature&#39;s relationship to another feature. The spatially relative terms are intended to cover different orientations of the device, including the features. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It should be appreciated that each term, which is defined in a commonly used dictionary, should be interpreted as having a meaning conforming to the relative skills and the background or the context of the present disclosure, and should not be interpreted in an idealized or overly formal manner unless defined otherwise. 
     Use of ordinal terms such as “first”, “second”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements. 
     In addition, in some embodiments of the present disclosure, terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. 
       FIG.  1    is a schematic view of a driving mechanism  1  in some embodiments of the present disclosure. The driving mechanism  1  may mainly include a case  10 , a base  20 , a movable portion  30 , a driving assembly  40 , a position sensing assembly  50 , a holder  60 , a substrate  70 , an optical sensor  80 , and a control assembly  82 . 
     The driving mechanism  1  may be used for driving an optical assembly  100 , and the optical assembly  100  has a main axis O. In particular, the case  10  and the base  20  may be called as a fixed portion F, and an accommodation space S is formed in the case  10  and the base  20 . The movable portion  30  and the optical assembly  100  are disposed in the accommodation space S. The movable portion  30  is movably connected to the fixed portion, and the optical assembly  100  is disposed on the movable portion  30 . For example, the movable portion  30  may be connected to the optical assembly  100  through a connecting portion  34 . Therefore, when the movable portion  30  is moving relative to the fixed portion F, the optical assembly  100  may be moved by the movable portion  30  to move relative to the fixed portion F. However, the present disclosure is not limited thereto. The driving mechanism also may be used for driving other mechanisms, such as vibration-typed motors, depending on design requirement. 
       FIG.  2    is a top view of the base  20 , the movable portion  30 , and the driving assembly  40 . In some embodiments, as shown in  FIG.  2   , the movable portion  30  has an opening  36 , and the optical assembly  100  may be disposed in the opening  36 . The driving assembly  40  may include a first driving element  42  and a second driving element  44 , the first driving element  42  includes a first driving unit  42 A and a second driving unit  42 B, and the second driving element  44  includes a third driving unit  44 A and a fourth driving unit  44 B. The first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B are used for driving the movable portion  30  to move relative to the fixed portion F. 
     In some embodiments, the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B are made of a shape memory alloy (SMA) and are strip-shaped. The length of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B changes as the crystal structure of SMA changes with temperature. From the center of the transition temperature, the length of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B increases as the temperature decreases, and the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B contracts as the temperature increases. In some embodiments, when a signal (e.g. voltage or current) is provided to the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B, the temperature may be increased by the thermal effect of a current, so that the length of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B may be decreased. Conversely, if a signal having a lower intensity is provided which makes the heating rate lower than the heat dissipation rate of the environment, the temperature of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, or the fourth driving unit  44 B may be decreased, and the length may be increased. 
     As shown in  FIG.  1    and  FIG.  2   , in some embodiments, the base  20  of the fixed portion F has an extension portion  22 , the movable portion  30  has a protruding portion  32 , an end of the driving assembly  40  may be disposed on the extension portion  22 , and another end of the driving assembly  40  may be disposed on the protruding portion  32 . As shown in 
       FIG.  2   , in some embodiments, the first driving unit  42 A extends from the extension portion  22  to the protruding portion  32  in a first direction D 1  (X direction), the second driving unit  42 B extends from the extension portion  22  to the protruding portion  32  in a second direction D 2  (−X direction), the third driving unit  44 A extends from the extension portion  22  to the protruding portion  32  in a third direction D 3  (−Y direction), the fourth driving unit  44 B extends from the extension portion  22  to the protruding portion  32  in a fourth direction D 4  (Y direction). The first direction D 1  is different than the third direction D 3 , the second direction D 2  is different than the third direction D 3 , the first direction D 1  is substantially parallel to the second direction D 2 , and the third direction is substantially parallel to the fourth direction D 4 . 
     As a result, the movable portion  30  may be moved relative to the fixed portion F in different directions by controlling the lengths of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B. For example, the first driving element  42  may drive the movable portion  30  to move relative of the fixed portion F in a first dimension (X direction or −X direction), and the second driving element  44  may drive the movable portion  30  to move relative of the fixed portion F in a second dimension (Y direction or −Y direction). In other words, the driving assembly  40  may connect the fixed portion F and the movable portion  30  to drive the movable portion  30  moving relative to the fixed portion F. 
     The position sensing assembly  50  may include a first position sensor  52 , a second position sensor  54 , a first reference element  56 , and a second reference element  58 . The first position sensor  52  and the second position sensor  54  may be disposed on the fixed portion F (e.g. the base  20 ), and the first reference element  56  and the second reference element  58  may be disposed on the optical assembly  100 . The first position sensor  52  corresponds to the first reference element  56  (e.g. align in Z direction), and the second position sensor  54  corresponds to the second reference element  58  (e.g. align in Z direction). 
     In some embodiments, the first position sensor  52  and the second position sensor  54  may be, for example, a Hall sensor, a magnetoresistance effect sensor (MR sensor), a giant magnetoresistance effect sensor (GMR Sensor), a tunneling a magnetoresistance effect sensor (TMR Sensor), or a fluxgate sensor. 
     In some embodiments, the first reference element  56  and the second reference element  58  may be sensing magnets, such as having a first magnetic unit and a second magnetic unit, respectively. When the movable portion  30  moves relative to the fixed portion F, the first position sensor  52  and the second position sensor  54  may detect the intensity difference of the magnetic field generated by the first reference element  56  and the second reference element  58 , so the position of the movable portion  30  relative to the fixed portion F may be achieved. 
     In some embodiments, the position sensing assembly  50  is at least partially disposed in the accommodation space S, such as the whole position sensing assembly  50  is disposed in the accommodation space S, or there may be a portion of the position sensing assembly  50  disposed outside the accommodation space S, but the present disclosure is not limited thereto. As a result, the distance between the position sensing assembly  50  and the movable portion  30  may be decreased, so more accurate position information of the movable portion  30  may be achieved. 
     A holder  60  and a substrate  70  may be provided on another side of the base  20 . The holder  60  may be disposed on the substrate  70 , and the base  20  may be disposed on the holder  60 . An optical sensor  80  may be disposed in the holder  60  to detect the light passing through the optical assembly  100 . Furthermore, a control assembly  82  may be disposed on the substrate  70  to control the driving mechanism  1 . Although the control assembly  82  is illustrated as disposed on the substrate  70 , the present disclosure is not limited thereto. For example, the control assembly  82  may be separated from the driving mechanism  1 . For example, when the driving mechanism  1  is disposed in an electronic apparatus (e.g. cell phone or tablets), the control assembly  82  may be the central processing unit (CPU) of the electronic apparatus, depending on design requirement. 
       FIG.  3    is a top view of some elements of the optical assembly  100 . Refer to  FIG.  1    and  FIG.  3   , the optical assembly  100  includes a cover  110 , a bottom  12 , an inner movable portion  130 , a first inner driving element  140 , a second inner driving element  160 , a first resilient element  170 , and a second resilient element  172 . Moreover, an optical element (not shown) may be disposed in the optical assembly  100 , such as disposed on the inner movable portion  130 . The optical element may include a lens, a mirror, a prism, a splitter, or an aperture. The optical assembly  100  may move the optical element to achieve auto focus (AF) or optical image stabilization (OIS). 
     The cover  110  and the bottom  120  may be called as an inner fixed portion IF. The cover  110  and the bottom  120  may be combined to form as the outer case of the optical assembly  100 . For example, the bottom  120  may be fixed on the cover  110 . It should be realized that an opening may be formed on the cover  110 , and another opening may be formed on the bottom  120 . The center of the opening of the cover  110  corresponds to the main axis O of the optical assembly  100 , and the opening of the bottom  120  corresponds to the optical sensor  80  disposed outside the optical assembly  100 . Therefore, the optical element disposed in the optical assembly  100  may perform focus to the optical sensor  80  along the main axis O. 
     A through hole may be formed on the inner movable portion  130 , the optical element may be fixed in the through hole, and the first inner driving element  140  may be disposed on the outer surface of the inner movable portion  130 . The second inner driving element  160  may be affixed on the cover  110 . It should be noted that in this embodiment, the second inner driving element  160  and the first reference element  56  or the second reference element  58  are the same magnetic element. In other words, the second inner driving element  160  may be used for driving the inner movable portion  130 , and may act as the first reference element  56  and the second reference element  58  as well, so that the position of the optical assembly  100  may be detected by the first position sensor  52  and the second position sensor  54 . Therefore, the number of the elements in the driving mechanism  1  may be reduced to achieve miniaturization. 
     The first inner driving element  140  and the second inner driving element  160  may be called as the inner driving assembly ID to drive the inner movable portion  130  to move relative to the inner fixed portion IF. It should be realized that the interaction between the second inner driving element  160  and the first inner driving element  140  may generate a magnetic force to move the inner movable portion  130  relative to the inner fixed portion IF along the main axis O, so fast focus may be achieved. 
     In this embodiment, the inner movable portion  130  and the optical element disposed therein are movably disposed in the inner fixed portion IF. More specifically, the inner movable portion  130  may be connected to the inner fixed portion IF and suspended in the inner fixed portion IF ( FIG.  3   ) through the first resilient element  170  and the second resilient element  172  including metal material. When current is passed through the first inner driving element  140 , the first inner driving element  140  may interact with the magnetic field of the second inner driving element  160  to generate an electromagnetic force. As a result, the inner movable portion  130  and the optical element may be moved relative to the inner fixed portion IF along the main axis O to achieve auto focus. 
     In some embodiments, additional circuit may be provided on the bottom  120  to electrically connect to other electronic elements disposed in or outside the optical assembly  100  for auto focus or optical image stabilization. The circuit on the bottom  120  may transmit electric signal to the first inner driving element  140  through the first resilient element  170  or the second resilient element  172 , so the movement of the inner movable portion  130  in X, Y, or Z direction may be controlled. 
     When the optical assembly  100  is assembled, the second resilient element  172  and the bottom  120  may be combined by soldering or laser welding to allow the first inner driving element  140  being electrically connected to external circuit. 
     Moreover, in some embodiments, a plurality of additional driving coils (not shown) may be embedded in the bottom  120  to interact with the second inner driving element  160 , so the inner movable portion  130  may be moved. When the first inner driving element  140  and the additional driving coils in the bottom  120  interact with the second inner driving element  160 , driving forces having different directions may be generated to achieve auto focus and optical image stabilization. 
       FIG.  4    is a block diagram showing the connection of some elements of the driving mechanism  1 . In some embodiments, as shown in  FIG.  4   , the control assembly  82  may provide a control signal C to the driving assembly  40 , so that the driving assembly  40  may be driven by the control signal C from the control assembly  82 . The position sensing assembly  50  may provide a position signal P (e.g. including a first position signal P 1  and a second position signal P 2 ) to the control assembly  82 . For example, the first position sensor  52  may provide the first position signal P 1  to the control assembly  82 , and the second position sensor  54  may provide the second position signal P 2  to the control assembly  82 . The first position signal P 1  and the second position signal P 2  may include the position information of the movable portion  30  relative to the fixed portion F in different dimensions. Therefore, the control assembly  82  may provide a control signal C to the driving assembly  40  corresponding to the position signal P provided by the position sensing assembly  50 , so the position of the movable portion  30  relative to the fixed portion F may be controlled by the driving assembly  40 . 
     In some embodiments, the control signal C may include a first driving signal C 1  provided to the first driving unit  42 A, a second driving signal C 2  provided to the second driving unit  42 B, a third driving signal C 3  provided to the third driving unit  44 A, and a fourth driving signal C 4  provided to the fourth driving unit  44 B to separately drive the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B. In some embodiments, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  may include periodic signal having a lower frequency than the maximum frequency. In other words, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  does not include the periodic signal having a frequency higher than the maximum frequency, so that the movable portion  30  may vibrate relative to the fixed portion F by a frequency less than the maximum frequency. In some embodiments, the maximum frequency may be, for example, about 10000 Hz, and the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  does not include the periodic signal having a frequency higher than 10000 Hz, but the present disclosure is not limited thereto. As a result, other elements in the driving mechanism  1  may be prevented from being interfered by the signal with a frequency that is too high. In some embodiments, the frequency of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  may be less than the maximum response frequency of the driving mechanism to effectively drive the driving mechanism  1 . 
     In some embodiments, the driving mechanism  1  may also include an environment sensing assembly  84  (shown in  FIG.  4   ), which may be disposed on the substrate  70  to detect the influence of the environment on the driving mechanism  1 , and then provide an environmental signal E to the control assembly  82 . The control assembly  82  may provide the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  based on the environmental signal E. In some embodiments, the environment sensing assembly  84  may include an inertia sensing element, such as a gyroscope, an accelerometer, an angular velocity meter, or a gravity direction sensor, etc., to detect the inertia of the driving mechanism  1 . 
     In some embodiments, after receiving the environmental signal E, the control assembly  82  filters and removes the high-frequency signals in the environmental signal E to prevent the environmental signal E being interfered by high-frequency noise. For example, signals in the environmental signal E with a frequency higher than 10000 Hz may be removed, or signals with a frequency higher than the maximum frequency may be removed. 
     Next, how the control assembly  82  controls the driving assembly  40  is described.  FIG.  5    is a schematic view of the control signal C when the control assembly  82  is in a preparation mode. At this time, the control assembly  82  drives the driving assembly  40  according to the position signal P, so that the movable portion  30  is positioned at a predetermined position relative to the fixed portion F (as shown in  FIG.  2   ). For example, at this time, the control assembly  82  may drive the first driving element  42 A according to the first position signal P 1 , and may drive the second driving element  42 B according to the second position signal P 2 , so that the movable portion  30  is at the predetermined position relative to the fixed portion F. Also, as an applied driving method, the first driving signal C 1  and the second driving signal C 2  may be calculated based on the first position signal P 1  to control the first driving element  42 , that is, the first driving unit  42 A and the second driving unit  42 B. The third driving signal C 3  and the fourth driving signal C 4  may be calculated based on the second position signal P 2  to control the second driving element  44 , that is, the third driving unit  44 A and the fourth driving unit  44 B. It should be noted that at this time, the control signal C (for example, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , or the fourth driving signal C 4 ) does not include a periodic signal with a frequency higher than the maximum frequency (e.g. higher than 10000 Hz). For example, the control signal C may only include a DC signal (e.g. DC current or DC voltage). 
     As shown in  FIG.  5   , at this time, the signal intensities of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , or the fourth driving signal C 4  are respectively shown as overlapped to a first original intensity C 01 , a second original intensity C 02 , a third original intensity C 03 , and a fourth original intensity C 04 , respectively. However, it should be noted that at this time, the first original intensity C 01 , the second original intensity C 02 , and the third original intensity C 03 , and the fourth original intensity C 04  of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are voltages or currents higher than zero. In other words, in the preparation mode, the intensities (such as voltage or current) of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are higher than zero, so that a voltage or current that is not equal to zero passes through the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B. In this way, the probability of occurrence of surges may be reduced. Since the surge includes high-frequency signals, if the probability of occurrence of surge is reduced, high-frequency noise may be reduced, thereby reducing the probability of noise generated when the driving mechanism  1  operating. It should be noted that under this condition, the heating rate of the control signal C to the driving assembly  40  is less than the heat dissipation rate of the environment to the driving assembly  40 , so the temperature of the driving assembly  40  will not keep increase, but will be maintained at a basic temperature. 
       FIG.  6 A  is a schematic view of the control signal C when the control assembly  82  is in the first control mode, and  FIG.  6 B  is a schematic view showing the tension differences of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  42 C, and the fourth driving unit  42 D between the first control mode and the preparation mode in  FIG.  5   . In the first control mode, the control assembly  82  controls the driving assembly  40  to drive the movable portion  30  to move in a first target direction relative to the fixed portion F. This embodiment uses the −X direction as an example, but it is not limited thereto. In the first control mode, the control assembly  82  may control the driving assembly  40  according to the first position signal P 1  and the second position signal P 2 . 
     As shown in  FIG.  6 A , during the first control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  have intensities (such as voltage or current) higher than zero. At this time, the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , the intensity of the second driving signal C 2  is less than the second original intensity C 02 , the intensity of the third driving signal C 3  is higher than the third original intensity C 03 , and the intensity of the fourth driving signal C 4  is higher than the fourth original intensity C 04 . In other words, when compared to the preparation mode, the control assembly  82  increases the voltage or current of the first driving signal C 1 , decreases the voltage or current of the second driving signal C 2 , increases the voltage or current of the third driving signal C 3 , and increases the voltage or current of the fourth driving signal C 4  in the first control mode. As a result, as shown in  FIG.  6 B , when compared to the preparation mode, the tension of the first driving unit  42 A increases, the tension of the second driving unit  42 B decreases, the tension of the third driving unit  44 A increases, and the tension of the fourth driving unit  44 B increases in the first control mode, so that the movable portion  30  may be driven to move in the −X direction. 
     In some embodiments, in the first control mode, the voltage or current of the first driving signal C 1  is higher than the voltage or current of the second driving signal C 2 . For example, as shown in  FIG.  6 A , the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , and the intensity of the second driving signal C 2  is less than the second original intensity C 02 . In some embodiments, the first original intensity C 01  may be substantially equal to the second original intensity C 02 , so the voltage or current of the first driving signal C 1  may be higher than the voltage or current of the second driving signal C 2 . In other words, the tension of the first driving unit  42 A increases, and the tension of the second driving unit  42 B decreases, whereby a force in the −X direction may be applied to the movable portion  30  to move the movable portion  30  in the −X direction. 
     In the first control mode, the control signal C (including the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4 ) does not include a periodic signal with a frequency higher than the maximum frequency (for example, 10000 Hz). In this way, the elements of the driving mechanism  1  may be prevented from being interfered by signals with high frequencies. In some embodiments, as shown in  FIG.  6 A , in the first control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  only have a DC voltage or DC current rather than AC voltage or AC current. In other words, in the first control mode, the intensities of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are substantially constants. In this way, the element of the driving mechanism  1  may be protected from interference by signals with excessive frequencies. 
     In some embodiments, in the first control mode, the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  (i.e. the absolute value of the intensity difference between the first driving signal C 1  and the first original intensity C 01 ) is different than the absolute value of the voltage or current of the third driving signal C 3  increased by the control assembly  82  (i.e. the absolute value of the intensity difference between the third driving signal C 3  and the third original intensity C 03 ). For example, as shown in  FIG.  6 A , the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  may be higher than the absolute value of the voltage or current of the third driving signal C 3  increased by the control assembly  82 , that is, the intensity difference between the first driving signal C 1  and the first original intensity C 01  may be higher than the intensity difference between the third driving signal C 3  and the third original intensity C 03 . Thereby, the first driving unit  42 A receiving the first driving signal C 1  may generate a higher driving force than the third driving unit  44 A receiving the third driving signal C 3  to control the moving direction of the movable portion  30 . In some embodiments, in the first control mode, the absolute value of the intensity difference between the first driving signal C 1  and the first original intensity C 01  is about 2 times of the absolute value of the intensity difference between the third driving signal C 3  and the third original intensity C 03 , but the present disclosure is not limited thereto. 
     In addition, in some embodiments, the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  (i.e. the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01 ) is different than the absolute value of the voltage or current of the fourth driving signal C 4  increased by the control assembly  82  (i.e. the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04 ) in the first control mode. For example, as shown in  FIG.  6 A , the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  may be higher than the absolute value of the voltage or current of the fourth driving signal C 4  increased by the control assembly  82 . In other words, the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01  may be higher than the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04 . Thereby, when compared with the fourth driving unit  44 B which receives the fourth driving signal C 4 , the first driving unit  42 A which receives the first driving signal C 1  may generate a higher driving force to control the moving direction of the movable portion  30 . In some embodiments, the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01  is about 2 times of the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04  in the first control mode, but the present disclosure is not limited thereto. 
     In some embodiments, the intensity difference between the third driving signal C 3  and the third original intensity C 03  may be substantially equal to the intensity difference between the fourth driving signal C 4  and the fourth original intensity C 04  in the first control mode. In other words, the net force received by the movable portion  30  in the Y direction is about 0 at this time, and the force applied on the movable portion  30  by the third driving unit  44 A and the fourth driving unit  44 B may be balanced to stabilize the movable portion  30  in the Y direction. 
     Therefore, the first driving element  42  may be used to drive the movable portion  30  to move in the −X direction, and the second driving element  44  may be used to prevent the movable portion  30  from rotating during translation to stabilize the movable portion  30 . 
     In addition, the control assembly  82  further includes a second control mode for controlling the driving assembly  40 .  FIG.  7 A  is a schematic view of the control signal C of the control assembly  82  in the second control mode, and  FIG.  7 B  is a schematic view showing the tension differences of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B between the second control mode and the preparation mode in  FIG.  5   . In the second control mode, the control assembly  82  controls the driving assembly  40  to move the movable portion  30  relative to the fixed portion F in a second target direction. Counterclockwise rotation is used as an example in this embodiment, but it is not limited thereto. In the second control mode, the control assembly  82  may control the driving assembly  40  according to the first position signal P 1  and the second position signal P 2 . 
     As shown in  FIG.  7 A , during the second control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  have intensities (such as voltage or current) higher than zero. At this time, the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , the intensity of the second driving signal C 2  is higher than the second original intensity C 02 , the intensity of the third driving signal C 3  is less than the third original intensity C 03 , and the intensity of the fourth driving signal C 4  is less than the fourth original intensity C 04 . In other words, when compared to the preparation mode, the control assembly  82  increases the voltage or current of the first driving signal C 1 , increases the voltage or current of the second driving signal C 2 , decreases the voltage or current of the third driving signal C 3 , and decreases the voltage or current of the fourth driving signal C 4  in the second control mode. As a result, as shown in  FIG.  7 B , when compared to the preparation mode, the tension of the first driving unit  42 A increases, the tension of the second driving unit  42 B increases, the tension of the third driving unit  44 A decreases, and the tension of the fourth driving unit  44 B decreases in the second control mode, so that the movable portion  30  may be driven to rotate in the counterclockwise direction. 
     In the second control mode, the control signal C (including the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4 ) does not include a periodic signal with a frequency higher than the maximum frequency (for example, 10000 Hz). In this way, the elements of the driving mechanism  1  may be prevented from being interfered by signals with high frequencies. In some embodiments, as shown in  FIG.  7 A , in the second control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  only have a DC voltage or DC current rather than AC voltage or AC current. In other words, in the second control mode, the intensities of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are substantially constants. In this way, the element of the driving mechanism  1  may be protected from interference by signals with excessive frequencies. 
     In addition, the control assembly  82  further includes a third control mode for controlling the driving assembly  40 .  FIG.  8 A  is a schematic view of the control signal C of the control assembly  82  in the third control mode, and  FIG.  8 B  is a schematic view showing the tension differences of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B between the third control mode and the preparation mode in  FIG.  5   . In the third control mode, the control assembly  82  controls the driving assembly  40  to move the movable portion  30  relative to the fixed portion F in a first target direction. −X direction is used as an example in this embodiment, but it is not limited thereto. In the third control mode, unlike the first control mode, the control assembly  82  not only controls the driving assembly  40  according to the position signal P (for example, including the first position signal P 1  and the second position signal P 2 ), but also controls the driving assembly  40  according to the environmental signal E. Thereby, the influence of the environment on the driving mechanism  1  may be reduced, and optical image stabilization may be achieved by translational movement. 
     As shown in  FIG.  8 A , during the third control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  have intensities (such as voltage or current) higher than zero. At this time, the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , the intensity of the second driving signal C 2  is less than the second original intensity C 02 , the intensity of the third driving signal C 3  is less than the third original intensity C 03 , and the intensity of the fourth driving signal C 4  is less than the fourth original intensity C 04 . In other words, when compared to the preparation mode, the control assembly  82  increases the voltage or current of the first driving signal C 1 , decreases the voltage or current of the second driving signal C 2 , decreases the voltage or current of the third driving signal C 3 , and decreases the voltage or current of the fourth driving signal C 4  in the third control mode. As a result, as shown in  FIG.  7 B , when compared to the preparation mode, the tension of the first driving unit  42 A increases, the tension of the second driving unit  42 B decreases, the tension of the third driving unit  44 A decreases, and the tension of the fourth driving unit  44 B decreases in the third control mode, so that the movable portion  30  may be driven to rotate in the −X direction. Moreover, the required energy of the driving mechanism  1  may be decreased by decreasing the tensions of the third driving unit  44 A and the fourth driving unit  44 B to save energy. 
     In some embodiments, in the third control mode, the voltage or current of the first driving signal C 1  is higher than the voltage or current of the second driving signal C 2 . For example, as shown in  FIG.  8 A , the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , and the intensity of the second driving signal C 2  is less than the second original intensity C 02 . In some embodiments, the first original intensity C 01  may be substantially equal to the second original intensity C 02 , so the voltage or current of the first driving signal C 1  may be higher than the voltage or current of the second driving signal C 2 . In other words, the tension of the first driving unit  42 A increases, and the tension of the second driving unit  42 B decreases, whereby a force in the −X direction may be applied to the movable portion  30  to move the movable portion  30  in the −X direction. 
     In the second control mode, the control signal C (including the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4 ) does not include a periodic signal with a frequency higher than the maximum frequency (for example, 10000 Hz). Alternatively, in some embodiments, the control signal C only has a periodic signal with identical frequency to the environmental signal E in the third control mode. In this way, the elements of the driving mechanism  1  may be prevented from being interfered by signals with high frequencies. In some embodiments, as shown in  FIG.  8 A , in the third control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  only have a DC voltage or DC current rather than AC voltage or AC current. In other words, in the first control mode, the intensities of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are substantially constants. In this way, the element of the driving mechanism  1  may be protected from interference by signals with excessive frequencies. 
     In some embodiments, in the third control mode, the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  (i.e. the absolute value of the intensity difference between the first driving signal C 1  and the first original intensity C 01 ) is different than the absolute value of the voltage or current of the third driving signal C 3  increased by the control assembly  82  (i.e. the absolute value of the intensity difference between the third driving signal C 3  and the third original intensity C 03 ). For example, as shown in  FIG.  8 A , the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  may be higher than the absolute value of the voltage or current of the third driving signal C 3  increased by the control assembly  82 , that is, the intensity difference between the first driving signal C 1  and the first original intensity C 01  may be higher than the intensity difference between the third driving signal C 3  and the third original intensity C 03 . 
     Thereby, the first driving unit  42 A receiving the first driving signal C 1  may generate a higher driving force than the third driving unit  44 A receiving the third driving signal C 3  to control the moving direction of the movable portion  30 . In some embodiments, in the third control mode, the absolute value of the intensity difference between the first driving signal C 1  and the first original intensity C 01  is about 2 times of the absolute value of the intensity difference between the third driving signal C 3  and the third original intensity C 03 , but the present disclosure is not limited thereto. 
     In addition, in some embodiments, the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  (i.e. the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01 ) is different than the absolute value of the voltage or current of the fourth driving signal C 4  increased by the control assembly  82  (i.e. the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04 ) in the third control mode. For example, as shown in  FIG.  8 A , the absolute value of the voltage or current of the first driving signal C 1  increased by the control assembly  82  may be higher than the absolute value of the voltage or current of the fourth driving signal C 4  increased by the control assembly  82 . In other words, the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01  may be higher than the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04 . Thereby, when compared with the fourth driving unit  44 B which receives the fourth driving signal C 4 , the first driving unit  42 A which receives the first driving signal C 1  may generate a higher driving force to control the moving direction of the movable portion  30 . In some embodiments, the absolute value of the difference between the first driving signal C 1  and the first original intensity C 01  is about 2 times of the absolute value of the difference between the fourth driving signal C 4  and the fourth original intensity C 04  in the third control mode, but the present disclosure is not limited thereto. 
     Therefore, the first driving element  42  may drive the movable portion  30  to move in the −X direction. Since the intensity of the driving signal of the second driving element  44  is reduced, the energy required in the third control mode may be reduced to save energy. 
     In addition, the control assembly  82  further includes a fourth control mode for controlling the driving assembly  40 . The fourth control mode is substantially similar to the second control mode, so please referring back to  FIG.  7 A  and  FIG.  7 B .  FIG.  7 A  is a schematic view of the control signal C of the control assembly  82  in the fourth control mode, and  FIG.  7 B  is a schematic view showing the tension differences of the first driving unit  42 A, the second driving unit  42 B, the third driving unit  44 A, and the fourth driving unit  44 B between the fourth control mode and the preparation mode in  FIG.  5   . In the fourth control mode, the control assembly  82  controls the driving assembly  40  to move the movable portion  30  relative to the fixed portion F in a second target direction. Counterclockwise rotation is used as an example in this embodiment, but it is not limited thereto. In the second control mode, the control assembly  82  may control the driving assembly  40  according to the first position signal P 1  and the second position signal P 2 . In the fourth control mode, unlike the second control mode, the control assembly  82  not only controls the driving assembly  40  according to the position signal P (for example, including the first position signal P 1  and the second position signal P 2 ), but also controls the driving assembly  40  according to the environmental signal E. Thereby, the influence of the environment on the driving mechanism  1  may be reduced, and optical image stabilization may be achieved by rotational movement. 
     As shown in  FIG.  7 A , during the fourth control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  have intensities (such as voltage or current) higher than zero. At this time, the intensity of the first driving signal C 1  is higher than the first original intensity C 01 , the intensity of the second driving signal C 2  is higher than the second original intensity C 02 , the intensity of the third driving signal C 3  is less than the third original intensity C 03 , and the intensity of the fourth driving signal C 4  is less than the fourth original intensity C 04 . In other words, when compared to the preparation mode, the control assembly  82  increases the voltage or current of the first driving signal C 1 , increases the voltage or current of the second driving signal C 2 , decreases the voltage or current of the third driving signal C 3 , and decreases the voltage or current of the fourth driving signal C 4  in the fourth control mode. As a result, as shown in  FIG.  7 B , when compared to the preparation mode, the tension of the first driving unit  42 A increases, the tension of the second driving unit  42 B increases, the tension of the third driving unit  44 A decreases, and the tension of the fourth driving unit  44 B decreases in the fourth control mode, so that the movable portion  30  may be driven to rotate in the counterclockwise direction. 
     In the fourth control mode, the control signal C (including the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4 ) does not include a periodic signal with a frequency higher than the maximum frequency (for example, 10000 Hz). In this way, the elements of the driving mechanism  1  may be prevented from being interfered by signals with high frequencies. In some embodiments, as shown in  FIG.  7 A , in the fourth control mode, the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  only have a DC voltage or DC current rather than AC voltage or AC current. In other words, in the fourth control mode, the intensities of the first driving signal C 1 , the second driving signal C 2 , the third driving signal C 3 , and the fourth driving signal C 4  are substantially constants. In this way, the element of the driving mechanism  1  may be protected from interference by signals with excessive frequencies. 
       FIG.  9 A  is a schematic view of an optical assembly  100 A according to some embodiments of the present disclosure, and  FIG.  9 B  is a top view of some elements of the optical assembly  100 A. The portions of the optical assembly  100 A that are similar to the aforementioned optical assembly  100  will not be repeated here. It should be noted that the first reference element  56 , the second reference element  58  and the second inner driving element  160  of the optical assembly  100 A are different elements. For example, the first reference element  56  and the second reference element  58  of the optical assembly  100 A may be disposed on the base  120  and separated from the inner driving element  160 . In this way, the distance between the first reference element  56  and the first position sensing element  52  and the distances between the second reference element  58  and the second position sensing element  54  may be reduced to improve the performance of the sensors. 
     In some embodiments, as shown in  FIG.  9 B , when viewed along the main axis O, the inner fixed portion IF (e.g. the base  120 ) has a polygonal structure, and the inner driving assembly ID (e.g. the second inner driving element  160 ) is positioned at a first side (e.g. the lower side) of the inner fixed portion IF, and the first position sensing element  52  is also positioned at the first side. In addition, when viewed along the main axis O, the inner driving assembly ID at least partially overlaps the first position sensing element  52  to reduce the size of the driving mechanism  1  in other directions, thereby achieving miniaturization. 
       FIG.  10 A  is a schematic view of an optical assembly  100 B according to some embodiments of the present disclosure, and  FIG.  10 B  is a top view of some elements of the optical assembly  100 B. The portions of the optical assembly  100 B that are similar to the aforementioned optical assembly  100  will not be repeated here. It should be noted that when viewed along the main axis O, the inner fixed portion IF (base  120 ) has a polygonal structure, and the optical assembly  100 B has a second inner driving element  162  disposed at the corner. The first position sensing element  52  and the first reference element  56  are positioned at the first side of the base  120  (e.g. the lower side), and the second position sensing element  54  and the second reference element  58  are positioned at the second side of the base  120  (e.g. left side). Thereby, the first position sensing element  52  and the second position sensing element  54  may respectively sense the movement of the optical assembly  100 B in different directions. In addition, magnetic interference may be avoided to enhance the accuracy of sensing by positioning the second inner driving element  162  at the corner and the position sensing element  50  at the side. 
       FIG.  11 A  is a schematic view of an optical assembly  100 C according to some embodiments of the present disclosure, and  FIG.  11 B  is a top view of some elements of the optical assembly  100 C. The portions of the optical assembly  100 C that are similar to the aforementioned optical assembly  100  will not be repeated here. It should be noted that when viewed along the main axis O, the inner fixed portion IF has a polygonal structure, and the inner driving assembly ID 2  (including the first inner driving element  142  and the second inner driving element  160 ) is positioned at the first side of the inner fixed portion IF (e.g. the left side), the first position sensing element  52  is positioned at the second side (e.g. the lower side), and the second position sensing element  54  is positioned at the first side. The second reference element  58  and the second inner driving element  160  are the same element, and the first reference element  56  and the second inner driving element  160  are disposed separately. 
     In addition, as shown in  FIG.  11 A , the second inner driving element  164  may include a multipolar magnet, and may have different magnetic pole directions. In the Z direction, the magnetic pole directions of the upper and lower sides of the second inner driving element  160  may be opposite. In the X direction, the magnetic pole direction of the left and right sides of the second inner driving element  160  may be opposite. At this time, the first inner driving element  142  may have a ring shape. Therefore, the driving force of the inner driving component ID 2  may be increased. 
       FIG.  12    is a top view of some elements of the optical assembly  100 D according to some embodiments of the present disclosure. When viewed along the main axis O, the inner fixing part IF has a polygonal structure, the inner driving element ID 3  (e.g. the second inner driving element  160 ) is positioned at the first side of the inner fixing part IF, the first position sensing element  52  and the first reference element  56  are positioned at a first corner of the inner fixed portion IF, and the second position sensing element  54  and the second reference element  58  are positioned at a second corner of the inner fixed portion IF. Because the first position sensing element  52  and the second position sensing element  54  are positioned at different corners, the movement of the optical assembly  100 D in different directions may be detected. In addition, the first position sensing element  52 , the second position sensing element  54 , and the second inner driving element  160  are positioned at different positions (for example, not overlap each other in the Z direction), so the chance of magnetic interference between the elements may be decreased to increase the accuracy of sensing. 
       FIG.  13    is a top view of some elements of the optical assembly  100 E according to some embodiments of the present disclosure. As shown in  FIG.  13   , when viewed along the main axis O, the inner fixed portion IF has a polygonal structure, and the inner driving assembly (for example, the second inner driving elements  162 ) is positioned at the first corner and the second corner of the inner fixed portion IF. The first position sensing element  52  is positioned at a first corner, and the second position sensing element  54  is positioned at a second corner. In other words, when viewed along the main axis O, the inner driving assembly ID (including the first inner driving element  140  and the second inner driving element  162 ) at least partially overlaps the first position sensing element  52 . In this way, no additional first reference elements  56  and second reference elements  58  is required, and the second inner driving elements  162  at the first corner and the second corner are respectively used as the first reference element  56  and the second reference element  58  to reduce the number of required elements, and miniaturization is achieved. 
       FIG.  14    is a top view of some elements of the optical assembly  100 F according to some embodiments of the present disclosure. As shown in  FIG.  14   , when viewed along the main axis O, the inner fixed portion IF has a polygonal structure, and the inner driving assembly ID (e.g. the second inner driving element  162 ) is positioned at a first corner of the inner fixed portion IF. The position sensing element  52  and the first reference element  56  are positioned at a second corner, and the second position sensing element  54  and the second reference element  58  are positioned at a third corner. The first position sensing element  52 , the second position sensing element  54 , and the second inner driving element  162  are positioned at different corners of the inner fixed portion IF, so the magnetic interference between the elements may be reduced. 
     In summary, a driving mechanism is provided. The driving mechanism includes a fixed portion, a movable portion, and a driving assembly. The movable portion is movably connected to the fixed portion. The driving assembly is used for driving the movable portion to move relative to the fixed portion. The driving assembly is driven by a control signal provided by a control assembly. The driving assembly includes shape memory alloy. Therefore, the control accuracy of the driving mechanism may be increased, and miniaturization may be achieved. 
     Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, and composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope of such processes, machines, manufacture, and compositions of matter, means, methods, or steps. In addition, each claim constitutes a separate embodiment, and the combination of various claims and embodiments are within the scope of the disclosure.