OPTICAL ELEMENT DRIVING MECHANISM

An optical element driving mechanism including a fixed part, a movable part, a first driving assembly, a second driving assembly, and a magnetic-permeable element is provided. The fixed part includes a bottom. The movable part holding an optical element with an optical axis is movable relative to the fixed part. The first driving assembly includes a first magnetic element and a first coil arranged along a first direction. The second driving assembly includes a second magnetic element and a second coil arranged along the first direction. The first driving assembly and the second driving assembly drive the movable part to move relative to the fixed part along a second direction and a third direction, respectively. The first direction, the second direction, and the third direction are different. When viewed in the optical axis, the first driving assembly at least partially overlaps the second driving assembly.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to a driving mechanism, and more particularly to an optical element driving mechanism.

Description of the Related Art

As technology has developed, nowadays many electronic devices (such as tablet computers and smartphones) are equipped with the functionality of shooting images and recording video. A user may operate an electronic device to capture various images and video thanks to an optical element and an optical element driving mechanism disposed on the electronic device.

When the user uses the electronic device equipped with the optical element driving mechanism, shock or vibration may occur, which may cause the image or video to come out blurry. As the demand for higher quality in images or videos is increasing, an optical element driving mechanism that is able to achieve displacement correction and shake compensation has been developed.

BRIEF SUMMARY OF THE INVENTION

An optical element driving mechanism including a fixed part, a movable part, a first driving assembly, a second driving assembly, and a magnetic-permeable element is provided. The fixed part includes a bottom. The movable part holding an optical element with an optical axis is movable relative to the fixed part. The first driving assembly includes a first magnetic element and a first coil. The first magnetic element and the first coil are arranged along a first direction. The second driving assembly includes a second magnetic element and a second coil. The second magnetic element and the second coil are arranged along the first direction. The first driving assembly and the second driving assembly drive the movable part to move relative to the fixed part along a second direction and a third direction, respectively. The first direction, the second direction, and the third direction are different. The magnetic-permeable element includes a first portion in contact with the first magnetic element and a second portion in contact with the second coil, and the first portion and the second portion are integrally formed. The first magnetic element and the second coil are located on the same horizontal plane. When viewed in the optical axis, the first driving assembly at least partially overlaps the second driving assembly. When viewed in the third direction, neither the first driving assembly nor the second driving assembly overlaps the bottom.

DETAILED DESCRIPTION OF THE INVENTION

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 this disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature “on” or “above” a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, so that the first and second features may not be in direct contact. Ordinal terms such as “first”, “second”, etc., used in the description and in claims do not by themselves connote any priority, precedence, or order of one element over another, but are used merely as labels to distinguish one element from another element having the same name. In addition, in different examples of this disclosure, symbols or alphabets may be used repeatedly.

The embodiments of this disclosure are described with the drawings.

FIG.1is a perspective view of an optical element driving mechanism801and an optical element802in accordance with some embodiments of this disclosure. The optical element802has an optical axis O. The optical axis O is an imaginary axis passing through the center of the optical element802. The optical element driving mechanism801is a telephoto lens. Specifically, the telephoto lens means a reflecting element (not shown) is used to change the direction of a light L. When the light L outside the optical element driving mechanism801enters the optical element driving mechanism801from a first direction (Y-axis), the light L is not parallel to the optical axis O and the light L may be substantially perpendicular to the optical axis O as shown inFIG.1. The reflecting element (not shown) may change the direction of the light L so that the light L is substantially parallel to the optical axis O. After the light L passes through the optical element driving mechanism801, an image may be imaged on a light-detection element (not shown) (e.g. a charge-coupled detector, CCD).

The optical element driving mechanism801may drive the optical element802to move such as moving, rotating, and the like. The optical element driving mechanism801may drive the optical element802to move along a direction that is parallel to the optical axis O to achieve auto focus (AF) to focus on the scene. Additionally, the optical element driving mechanism801may also drive the optical element802to move along a direction that is not parallel to the optical axis O to achieve optical image stabilization (OIS) to compensate the deviation of the imaged image caused by shake or being impacted and solve the problem of blurry images or video. The quality of the image may be enhanced by AF and OIS.

FIG.2is an exploded view of the optical element driving mechanism801inFIG.1. The optical element driving mechanism801includes a fixed part811, a movable part812, a first driving assembly880, and a second driving assembly890. The movable part812moves relative to the fixed part811and holds the optical element802. The fixed part811includes a case820, a frame830, and a bottom920. The movable part812includes four first elastic elements840, four second elastic elements850, a holder860, two magnetic-permeable elements870, a circuit assembly900, and two sensing elements910. The elements may be added or omitted.

The case820and the frame830are located above the bottom920. The case820are connected to the bottom920and the space formed therein may accommodate the frame830, the movable part812, the first driving assembly880, and the second driving assembly890, and the like.

The case820is made of magnetic-permeable material and thus may have good magnetic retentivity, concentrate the lines of magnetic field, and the like. Magnetic materials are materials that may be magnetized when a magnetic field is applied, such as ferromagnetic material, steel (e.g. steel plate cold common, SPCC), iron/Ferrum (Fe), Nickel (Ni), Cobalt (Co), an alloy thereof. Preferably, the case820is made of material with high magnetic permeability.

The frame830may be made of non-conductive material or magnetic-permeable material such as plastic or metal alloy. When the frame830is made of magnetic-permeable material, the frame830may also have good magnetic retentivity, concentrate the lines of magnetic field, and have higher structural strength compared with non-conductive material.

The case820includes a sidewall821perpendicular to the optical axis O and another sidewall822opposite to the sidewall821. An opening823and an opening824are formed on the sidewall821and the sidewall822, respectively. The positions of the opening823and the opening824correspond to the optical element802. The optical element802is disposed between the sidewall821and the sidewall822. After the light L passes through the reflecting element (not shown), the light L enters the optical element driving mechanism801via the opening823and leaves the optical element driving mechanism801via the opening824.

The first elastic elements840are located over the holder860. The first elastic elements840include elastic material and may be made of metal. The four second elastic elements850are elongated. The four second elastic elements850connect the four elastic elements840of the movable part812and the bottom920of the fixed part811, respectively. Generally, a current may be supplied to the second elastic elements850to make the first driving assembly880or the second driving assembly890generates an electromagnetic force. However, the circumstances that no current is supplied to the second elastic elements850of this disclosure are acceptable. The second elastic elements850may mainly function as support.

The holder860is disposed between the frame830and the bottom920. The holder860has a through hole861for holding the optical element802. In some embodiments, a screw and its corresponding threaded structure may be configured between the through hole861and the optical element802, so that the optical element802may be affixed in the through hole861. The holder860is spaced apart from the case820and the bottom920of the fixed part811, i.e. the holder860does not directly contact the case820and the bottom920.

The magnetic-permeable element870is made of magnetic-permeable material. Preferably, the magnetic-permeable element870is made of material with high magnetic permeability. The functionality of the magnetic-permeable element870will be described with regard toFIG.5.

The first driving assembly880includes four first magnetic elements881and four first coils882corresponding to the first magnetic elements881. Two of the first coils881and the other two first coils882are disposed on the opposite sides of the holder860. When viewed in the first direction (Y-axis), two of the first magnetic elements881and the other two first magnetic elements881are disposed on different sides of the optical axis O, and two of the first coils882and the other two first coils882are disposed on different sides of the optical axis O. The first magnetic element881and the first coil882are arranged along the first direction (Y-axis). The first driving assembly880may drive the holder860of the movable part812to move along a second direction (Z-axis) relative to the bottom920of the fixed part811to achieve AF.

The second driving assembly890includes two second magnetic elements891and two second coils892corresponding to the second magnetic elements891. One of the second coils892and the other one of the second coils892are disposed on the opposite sides of the holder860. When viewed in the first direction (Y-axis), one of the second magnetic elements891and the other one of the second magnetic elements891are disposed on different sides of the optical axis O, and one of the second coils892and the other one of the second coils892are disposed on different sides of the optical axis O. Therefore, when viewed in the first direction (Y-axis), the first driving assembly880and the second driving assembly890are disposed on different sides of the optical axis O. The second magnetic elements891and the second coils892are arranged along the first direction (Y-axis) as well. The second driving assembly890drives the holder860of the movable part812to move along a third direction (X-axis) relative to the bottom920of the fixed part811to achieve OIS. The first direction (Y-axis), the second direction (Z-axis), and the third direction (X-axis) are different. In this embodiment, the first direction (Y-axis), the second direction (Z-axis), and the third direction (X-axis) are substantially perpendicular to each other.

The lower surface of each of the first magnetic elements881faces the first coils882and the lower surface of each of the second magnetic elements891faces the second coils892. The lower surface of each of the first magnetic elements881is parallel to the lower surface of each of the second magnetic elements891.

Each of the first coils882includes a perforation883and a winding axis884. The winding axis884is an imaginary axis passing through the center of the perforation883. Each of the second coils892includes a perforation893and a winding axis894. The winding axis894is an imaginary axis passing through the center of the perforation893. The winding axis884of the first coil882is parallel to the winding axis894of the second coil892. When viewed in the second direction (Z-axis), the first coil882partially overlaps the second coil892.

As shown inFIG.2, each of the second magnetic elements891is disposed between two first magnetic elements881, and each of the second coils892is disposed between two first coils882. If one of the first magnetic elements881and one of the first coils882corresponding to each other are referred to as one first driving assembly880, then there is more than one first driving assembly880, and the second driving assembly890is disposed between the first driving assemblies880. The first driving assemblies880and the second driving assembly890are arranged along the second direction (Z-axis). The second direction (Z-axis) is substantially parallel to the optical axis O, so the optical axis O is also substantially parallel to the arrangement direction of the first driving assemblies880and the second driving assembly890.

When viewed in a direction that is parallel to the optical axis O, the first driving assembly880at least partially overlaps the second driving assembly890. Compared to the configuration that the first driving assembly880does not overlap the second driving assembly890, such a configuration may reduce the size of the optical element driving mechanism801in the first direction (Y-axis). For example, if the size of the first driving assembly880in the first direction (Y-axis) is a and the size of the second driving assembly890in the first direction (Y-axis) is b, the sum of the size of the first driving assembly880and the second driving assembly890is at least a+b when the first driving assembly880does not overlap the second driving assembly890. To the contrary, if the first driving assembly880does overlap the second driving assembly890when viewed in a direction that is parallel to the optical axis O as in this disclosure, then the sum of the size of the first driving assembly880and the second driving assembly890is less than a+b.

The circuit assembly900is disposed on the bottom920. The circuit assembly900may be a circuit board such as a flexible printed circuit (FPC), flexible-hard composite board, and the like. The circuit assembly900may include an electronic element (not shown) such as a capacitance, a resistor, an inductance, and the like. The first coils882and the second coils892are disposed on the circuit assembly900.

The sensing element910may be a Hall sensor, a magnetoresistance effect (MR) sensor, a giant magnetoresistance effect (GMR) sensor, a tunneling magnetoresistance effect (TMR) sensor, and the like. The sensing element910may sense the movement condition of the holder860of the movable part812relative to the bottom920of the fixed part811.

The two sensing elements910are disposed in the perforation883of one of the first coils882and the perforation893of one of the second coils892, respectively. The sensing elements910are also disposed on the circuit assembly900because the first coils882and the second coils892are disposed on the circuit assembly900. In this embodiment, the two sensing elements910may sense the movement condition of the holder860relative to the bottom920in different directions. For example, the sensing element910disposed in the perforation883of the first coil882may sense the movement condition of the holder860in the second direction (Z-axis) while the sensing element910disposed in the perforation893of the second coil892may sense the movement condition of the holder860in the third direction (X-axis).

Since the positions of the first coil882, the second coil892, and the sensing element910is pretty close to each other, the first coil882, the second coil892, and the sensing element900may be electrically connected to the circuit assembly900at the same time, so that the circuit is put together and thus the circuit route is simplified. That is the reason why no current flows through the second elastic element850of this disclosure is acceptable as described above.

Next, please refer toFIG.3andFIG.4together.FIG.3is a perspective view of the optical element driving mechanism801with some elements omitted.FIG.4is a side view of the optical element driving mechanism801with some elements omitted. As shown inFIG.3andFIG.4, when viewed in the third direction (X-axis), the first driving assembly880at least partially overlaps the optical element802, and the second driving assembly890at least partially overlaps the optical element802as well. Compared with configurations in which the first driving assembly880or the second driving assembly890does not overlap the optical element802, such a configuration may reduce the size of the optical element driving mechanism801in the first direction (Y-axis) and achieve miniaturization of the optical element driving mechanism801.

FIG.5is a schematic view of the magnetic-permeable element870, the first driving assembly880, and the second driving assembly890. The first magnetic elements881and the second magnetic elements891illustrated herein include multiple magnetic poles divided with dotted lines. The arrangement directions of the magnetic poles of the first magnetic elements881and the second magnetic elements891may be misunderstood. One may have the misperception that the magnetic poles of the first magnetic elements881and the second magnetic elements891are arranged in different, multiple directions. To avoid such misunderstandings, it should be noted that the word “the magnetic poles” used herein refer to a N-pole and S-pole pair that together generate closed lines of magnetic field.

Please refer toFIG.6andFIG.7to understand the arrangement directions of the magnetic poles of the first magnetic elements881.FIG.6andFIG.7are schematic views of any of the first magnetic elements881when viewed from the third direction (X-axis). The N-poles and the S-poles illustrated inFIG.6andFIG.7are exchangeable. The first magnetic element881may be a single multi-poles magnet (as shown inFIG.6) or a magnet formed by gluing multiple magnets (as shown inFIG.7). These two kinds of the first magnetic element881have different advantages. A single multi-poles magnet as shown inFIG.6is easy to be assembled, but a depletion region is formed in the middle of the multi-poles magnet during production. Magnetic force cannot be generated by the depletion region. If the first magnetic element881includes the depletion region, the weight of the optical element driving mechanism801may be increased. The magnet formed by gluing multiple magnets as shown inFIG.7does not have a deletion region, but additional gluing is required. It is noted that any of the second magnetic elements891may also be a single multi-poles magnet or a magnet formed by gluing multiple magnets. It means that when viewed from the second direction (Z-axis), the magnetic poles of the second magnetic elements891may have similar configurations asFIG.6orFIG.7.

Please refer toFIG.5again. The first coil882includes a first segment886and a second segment887parallel to the third direction (X-axis) and facing to each other. The second coil892includes a third segment896and a fourth segment897parallel to the second direction (Z-axis) and facing to each other. The first segment886, the second segment887, the third segment896, and the fourth segment897are “main current regions”. Main current regions are regions that the current passing through may generate electromagnetic driving force. Therefore, the electromagnetic driving force generated by the current passing through the first segment886, the second segment887, the third segment896, and the fourth segment897together with the first magnetic elements881and the second magnetic elements891may drive the holder860to move. The electromagnetic force generated by the regions that do not belong to “main current regions” (not labeled in inclined lines) is weaker, and thus it is more difficult for such electromagnetic force to drive the holder860to move.

The direction of the current flowing through the first segment886is opposite to that of the current flowing through the second segment887. To make the whole first coil882move toward the same direction, the direction of the magnetic field corresponding the first segment886and the direction of the magnetic field corresponding to the second segment887have to be opposite as well, which may be derived from the right-hand rule (the rule describing the relationship of the current, the magnetic field, and the electromagnetic force). Therefore, the pole of the first magnetic element881corresponding to the first segment886is different than the pole of the first magnetic element881corresponding to the second segment887. Similarly, the direction of the current flowing through the third segment896is opposite to the direction of the current flowing through the fourth segment897, so the pole of the second magnetic element891corresponding to the third segment896is different than the pole of the second magnetic element891corresponding to the fourth segment897.

The main current regions need to correspond to as much area of the poles as possible for generating as strong electromagnetic driving force as possible. Therefore, the arrangement direction of the magnetic poles of the first magnetic element881is the same as the arrangement direction of the first segment886and the second segment887. Additionally, the arrangement direction of the magnetic poles of the second magnetic element891is the same as the arrangement direction of the third segment896and the fourth segment897. Therefore, the magnetic poles of the first magnetic element881are arranged along the second direction (Z-axis), and the magnetic poles of the second magnetic element891are arranged along the third direction (X-axis).

In addition, for clarity of illustration, an arrow is used to indicate the direction of the electromagnetic driving force. The flow direction of the current may be clockwise or counterclockwise. When the current flows through the first coil882, the direction of the generated electromagnetic driving force between the main current regions (the first segment886and the second segment887) and the first magnetic element881is in the second direction (including +Z-axis and —Z-axis, only +Z-axis is shown inFIG.5), so the holder860may be driven to move along the second direction (Z-axis).

When the current flows through the second coil892, the direction of the generated electromagnetic driving force between the main current regions (the third segment896and the fourth segment897) and the second magnetic element891is in the third direction (including +X-axis and —X-axis, only +X-axis is shown inFIG.5), so the holder860may be driven to move along the third direction (X-axis).

The shape profile of the magnetic-permeable element870is designed to correspond to the shape profile of the first magnetic element881and the second magnetic element891. The magnetic-permeable element870may be integrally formed to simplify the gluing process. One magnetic-permeable element870is connected to two first magnetic elements881and one second magnetic element891at the same time. For example, for gluing one magnetic-permeable element870that is integrally formed to two first magnetic elements881and one second magnetic element891, the gluing process only has to be done once. If the magnetic-permeable element870is not integrally formed, then the gluing process of connecting the magnetic-permeable element870to two first magnetic elements881and one second magnetic element891has to be done several times. Thus, the magnetic-permeable element870that is integrally formed may simply the production process.

Furthermore, the volume of the first magnetic element881and the second magnetic element891may be small. If two first magnetic elements881and one second magnetic element891that are small are glued to one magnetic-permeable870, then a group of elements with larger volume is formed, which is advantageous for the consequent assembling.

When viewed in the first direction (Y-axis), the magnetic-permeable element870, the first driving assembly880, and the second driving assembly890partially overlap. Since the magnetic-permeable element870is placed close to the first magnetic element881and the second magnetic element891, the magnetic-permeable element870may attract and concentrate the lines of magnetic field of the first magnetic element881and the second magnetic element891to enhance the generated magnetic force.

FIG.8is a perspective view of the holder860illustrated from a different perspective thanFIG.1. The side of the holder860that is close to the bottom920includes a plurality of protrusions862and a plurality of recesses863. The holder860may be made of plastic, but plastic material deforms easily during the formation because of reasons such as thermal expansion and contraction. To avoid the magnetic-permeable element870cannot be received in the holder860because of the deformation of the holder860, the protrusions862of the holder860may be engaged with the magnetic-permeable element870. The protrusions862of the holder860are flakes. The recesses863of the holder860receive the magnetic-permeable element870.

FIG.9is a configuration of the first driving assembly880and the second driving assembly890in accordance with some other embodiments of this disclosure.FIG.10is a top view of the first driving assembly880and the second driving assembly890inFIG.9. In the following text, the same elements are denoted by the same symbols, similar elements are denoted by similar symbols, and the same contents are not repeated again.

In this embodiment, the positions of the second magnetic elements891of the second driving assembly890are exchanged with the positions of the second coils892of the second driving assembly890, so that the second coils892are located over the second magnetic elements891. The bottom surface of each of the first magnetic elements881faces the first coils882, and the top surface of each of the second magnetic elements891faces the second coils892. Additionally, the bottom surface of each of the first magnetic elements881and the top surface of each of the second magnetic elements891face different directions.

To avoid magnetic interference generated between the first magnetic elements881and the second coils892or between the second magnetic elements891and the first coils882, four additional magnetic-permeable elements970are provided. The four magnetic-permeable elements970are disposed between the first driving assembly880and the second driving assembly890. Therefore, when viewed in the second direction (Z-axis), the first driving assembly880, the second driving assembly890, and the magnetic-permeable elements970partially overlap.

As described above, an optical element driving mechanism is provided. Base on this disclosure, miniaturization of the optical element driving mechanism may be achieved by the arrangement and the configuration of the first driving assembly and the second driving assembly. Additionally, the displacement correction and the displacement compensation may be achieved by the first driving assembly and the second driving assembly.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of this disclosure. Those skilled in the art should appreciate that they may readily use this disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of this disclosure. In addition, the scope of this disclosure is not limited to the specific embodiments described in the specification, and each claim constitutes a separate embodiment, and the combination of various claims and embodiments are within the scope of the disclosure.