LENS DRIVING MECHANISM AND ELECTRONIC DEVICE HAVING THE SAME

Abstract

A lens driving mechanism is provided for moving a lens unit along a light axis, including a frame, a base, a lens holder, and a driving assembly. The frame has plastic material and forms an opening. The base is in contact with and fixed to the frame, wherein a space is formed between the base and the frame. The lens holder is movably disposed in the space for holding the lens unit, wherein an external light enters the space through the opening to the lens unit. The driving assembly is disposed in the space and is connected to the lens holder and the frame, to impel the lens unit to move along the light axis.

Claims

1. A lens driving mechanism for moving a lens unit along a light axis, comprising: a frame, comprising plastic and having an opening; a base, fixed to and in contact with the frame, wherein a space is formed between the base and the frame; a lens holder, movably disposed in the space for holding the lens unit, wherein an external light enters the space through the opening to the lens unit; and a driving assembly, disposed in the space and connected to the lens holder and the frame, to impel the lens unit to move along the light axis.

2. The lens driving mechanism as claimed in claim 1, wherein the frame further has a protrusion, a top surface, and a side surface extended from an edge of the top surface and toward the base, wherein the protrusion protrudes from an inner surface of the frame and is located corresponding to an adjoining area between the top and side surfaces, to enhance the structural strength of the frame.

3. The lens driving mechanism as claimed in claim 2, wherein the top surface has a quadrangular shape.

4. The lens driving mechanism as claimed in claim 1, wherein the frame comprises metal.

5. The lens driving mechanism as claimed in claim 1, further comprising a conductive wire directly formed on or in the frame by Molded Interconnect Device (MID) technology.

6. The lens driving mechanism as claimed in claim 1, wherein the driving assembly includes a first magnetic element and a second magnetic element respectively disposed on the frame and the lens holder, and the lens holder is moved relative to the frame and the base by a magnetic force generated by the first and second magnetic elements.

7. The lens driving mechanism as claimed in claim 6, wherein the frame further has a holding portion protruding from an inner surface of the frame and holding the first magnetic element in a predetermined position on the inner surface.

8. The lens driving mechanism as claimed in claim 7, wherein the holding portion forms a U-shaped structure with the first magnetic element received therein

9. The lens driving mechanism as claimed in claim 6, wherein the first magnetic element comprises a magnet, and the second magnetic element comprises a coil with an electrical current applied thereto.

10. The lens driving mechanism as claimed in claim 9, wherein the first magnetic element comprises a multipolar magnet.

11. The lens driving mechanism as claimed in claim 1, wherein the lens holder has a protruding slider, and the frame further has a restricting structure with the slider received therein to restrict movement of the slider.

12. The lens driving mechanism as claimed in claim 11, wherein the restricting structure has two restricting portions protruding from an inner surface of the frame, and a recess is formed between the two restricting portions and extended along the light axis, wherein the width of the recess exceeds that of the slider.

13. The lens driving mechanism as claimed in claim 11, wherein the lens driving mechanism has a substantially polygonal structure and further comprises two driving assemblies disposed on two opposite sides thereof to move the lens unit along the light axis, wherein the slider and the restricting structure are situated on a side of the lens driving mechanism different from the two opposite sides where the driving assemblies are disposed.

14. The lens driving mechanism as claimed in claim 1, wherein the frame forms a quadrangular shape and further has a plastic main body and a metal plate, the opening is formed on the main body, and the metal plate is disposed on a side of the main body.

15. The lens driving mechanism as claimed in claim 14, wherein the metal plate forms a plurality of holes, and the main body forms a plurality of protruding portions engaged in the holds.

16. An electronic device, comprising: the lens driving mechanism as claimed in claim 1; a housing; and a wireless communicating element, wherein the lens driving mechanism has a substantially polygonal structure, and the lens driving mechanism and the wireless communicating element are disposed in the housing, wherein the driving assembly is adjacent to a first side of the lens driving mechanism, and the wireless communicating element is adjacent to a second side of the lens driving mechanism different from the first side.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a more complete understanding of the embodiments, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings.

[0023] FIG. 1A shows a conventional voice coil motor connected to a transparent plate G and a circuit board P.

[0024] FIG. 1B is a cross-sectional view along line A-A in FIG. 1A.

[0025] FIG. 2 is an exploded diagram of a lens driving mechanism 20 according to an embodiment of the invention.

[0026] FIG. 3A is a perspective diagram of the lens driving mechanism in FIG. 2 with a transparent plate and a circuit board connected thereto.

[0027] FIG. 3B is a cross-sectional view along line B-B in FIG. 3A.

[0028] FIG. 4A is a perspective diagram of the frame in FIG. 3A.

[0029] FIG. 4B is a top view of the frame in FIG. 4A.

[0030] FIG. 5A is perspective diagram of the frame, the lens holder, and the first magnetic element when assembled to each other.

[0031] FIG. 5B is a top view of the frame, the lens holder, and the first magnetic element in FIG. 5A.

[0032] FIG. 6 perspective diagram of a lens driving mechanism according to another embodiment of the invention.

[0033] FIG. 7 perspective diagram of a lens driving mechanism according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0034] While the invention has been described in connection with various aspects, it should be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptation of the invention following, in general, the principles of the invention, including such departures from the present disclosure as come within the known and customary practice within the art to which the invention pertains.

[0035] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, and in which specific embodiments of which the invention may be practiced are shown by way of illustration. In this regard, directional terminology, such as top, bottom, front, back, etc., is used with reference to the orientation of the figures being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for the purposes of illustration and is in no way limiting.

[0036] FIG. 2 is an exploded diagram of a lens driving mechanism 20 according to an embodiment of the invention. As shown in FIG. 2, the lens driving mechanism 20 is provided for holding a lens unit (not shown), wherein a driving assembly having magnets and coils is disposed in the driving mechanism 20 to force the lens unit to move along the light axis L of the lens unit, so as to achieve auto focusing of a camera.

[0037] The lens driving mechanism 20 primarily comprises a frame 21, a lens holder 22, a base 23, an upper spring sheet S1, a lower spring sheet S2, at least a first magnetic element M, and at least a second magnetic element C. The frame 21 has a substantially quadrangular structure and forms an opening 210. Four side surfaces 212 are extended from a top surface 211 of the frame 21 toward the base 23. The base 23 is fixed to and in contact with the frame 21, and the lens holder 22 is movably disposed between the base 23 and the frame 21. The lens holder 22 has a through hole 220 for receiving and holding the lens unit (not shown). It should be noted that external light can enter the lens driving mechanism 20 via the opening 210 of the frame 21, sequentially propagate through the lens unit at the center of the lens holder 22 and the base 23, and finally reach an image sensor (such as CCD) to generate an image.

[0038] As depicted in FIG. 2, the first magnetic elements M are disposed on the inner surfaces of the frame 21, and the second magnetic elements C are disposed on the outer surfaces of the lens holder 22, corresponding to the first magnetic elements M. In this embodiment, the first magnetic elements M may comprise bi-polar or multipolar magnets, and the second magnetic elements C may comprise coils. To move the lens unit along the light axis L, an electrical current can be applied to the second magnetic elements C, and the magnetic fields generated by the second magnetic elements C can interact with those of the first magnetic elements M to generate a magnetic force. Thus, the lens unit can be controlled and moved along the light axis L by the magnetic force to achieve rapid focusing and OIS (Optical Image Stabilization). In some embodiments, the first magnetic elements M can be coils, and the second magnetic elements C can be bi-polar or multipolar magnets corresponding to the coils, so that the lens unit can also be controlled and moved along the light axis L by magnetic force.

[0039] Referring to FIGS. 2, 3A, and 3B, FIG. 3A is a perspective diagram of the lens driving mechanism 20 in FIG. 2 with a transparent plate G and a circuit board P assembled thereto, and FIG. 3B is a cross-sectional view along line B-B in FIG. 3A. As shown in FIG. 3A, a transparent plate G (such as plastic or glass plate) is assembled to the lens driving mechanism 20. Here, the transparent plate G is adhered to a flat top surface 211 of the frame 21, so as to protect the lens unit and other components in the lens driving mechanism 20, and allow light to enter the lens driving mechanism 20 through the transparent plate G. Therefore, an image sensor (such as CCD) can receive and transfer light into electronic signals. The lens driving mechanism 20 may be electrically connected to an external power source via the circuit board P. Moreover, the lens driving mechanism 20 may transmit electronic signals to a processor outside of the driving mechanism 20 via the circuit board P for data processing.

[0040] In FIGS. 2 and 3B, the lens holder 22 and the upper and lower spring sheets S1 and S2 are all disposed in the space 201 which is formed between the frame 21 and the base 23. The upper spring sheet S1 connects the frame 21 to the lens holder 22, and the lower spring sheet S2 connects the base 23 to the lens holder 22. In this embodiment, as the frame 21 comprises plastic (pure plastic or metal-doped plastic material), it can be integrally formed in one piece by injection molding or insert molding. Specifically, at least a protrusion 213 is directly formed on an inner surface of the frame 21 (FIG. 3B), corresponding to an adjoining area (corner) between the top surface 211 and the side surfaces 212. Hence, the top surface 211 of the frame 21 can have a large and flat adhesion area to enhance the connection between the frame 21 and the transparent plate G. Additionally, as the protrusion 213 is located corresponding to the adjoining area between the top surface 211 and the side surfaces 212, the structural strength of the frame 21 can also be improved.

[0041] In some embodiments, as the frame 21 may comprise plastic material which is doped with metal particles, the intensity of the magnetic field within the lens driving mechanism 20 can be increased when compared with pure plastic material, and the structural strength thereof can also be improved when compared with metal plate which is formed by conventional stamping process. Moreover, as the frame 21 comprises plastic material and therefore can be integrally formed in one piece, electrical circuits can be directly formed on or in the frame 21 by Molded Interconnect Device (MID) or Laser Direct Structuring (LDS) technologies. Thus, additional electronic element (such as the circuit board P in FIG. 3A) for electrical connection to the external circuits can be omitted, so as to reduce production cost and the dimensions of the lens driving mechanism 20.

[0042] FIG. 4A is a perspective diagram of the frame 21 in FIG. 3A, and FIG. 4B is a top view of the frame 21 in FIG. 4A. FIG. 5A is a perspective diagram of the frame 21, the lens holder 22, and the first magnetic element M when assembled to each other, and FIG. 5B is a top view of the frame 21, the lens holder 22, and the first magnetic element M in FIG. 5A. As shown in FIGS. 2 and 4A-5B, at least one protruding slider 221 is formed on the outer surface of the lens holder 22, and at least one restricting structure R1 is formed on the inner surface of the frame 21, corresponding to the slider 221. Each restricting structure R1 has two restricting portions R11 protruding from the inner surface of the frame 21, wherein a longitudinal recess R12 extended along the light axis L is formed between the two restricting portions R11, and the width of the recess R12 exceeds that of the slider 221. In this embodiment, as the slider 221 is received in the restricting structure R1, it can be restricted from moving along horizontal directions, so as to prevent from collision with other components in the lens driving mechanism 20.

[0043] Still referring to FIGS. 2, and 4A-5B, at least a holding portion R2 protrudes from an inner surface of the frame 21 and forms a U-shaped structure. The first magnetic element M is received and held in a recess R21 at the center of the holding portion R2, so as to prevent the first magnetic element M being separated from the frame 21, and secure the first magnetic element M in a predetermined position on the inner surface of the frame 21. As the frame 21 in this embodiment comprises plastic material and therefore can be integrally formed in one piece, the restricting structure R1 and the holding portion R2 can be directly formed on the inner surface of the frame 21 for respectively retaining the lens holder 22 and the first magnetic element M, instead of using additional positioning components, thereby efficiently reducing the cost of materials and assembly.

[0044] Furthermore, as shown in FIGS. 2, and 4A-5B, the lens driving mechanism 20 forms a substantially quadrangular structure and includes two set of driving assemblies (each driving assembly has a first magnetic element M and a second magnetic element C). Those driving assemblies are disposed on opposite sides of the lens holder 22 for moving the lens holder 22 and the lens unit along the light axis L. Specifically, the slider 221 and the restricting structure R1 are located on a side of the lens driving mechanism 20 different from the driving assemblies. In this embodiment, the sliders 221 and the restricting structures R1 are disposed on the left and right sides of the lens holder 22 (FIG. 5B), different from the driving assemblies (first magnetic element M) disposed on the upper and lower sides of the lens holder 22.

[0045] FIG. 6 illustrates a lens driving mechanism 20 according to another embodiment of the invention. As shown in FIG. 6, the frame 21 of the lens driving mechanism 20 has a hollow quadrangular main body 21 and a metal plate 24. The main body 21 comprises plastic material, and the metal plate 24 can be integrally formed on a side of the main body 21 by insert molding.

[0046] FIG. 7 illustrates a lens driving mechanism 20 according to another embodiment of the invention. The embodiment of FIG. 7 is different from the embodiment of FIG. 6 in that the metal plate 21 further forms a plurality of holds 240, and the main body 21 further forms a plurality of protruding portions respectively engaged in the holds 240.

[0047] According to the embodiments as described above, the invention further provides an electronic device that includes the lens driving mechanism 20 of any one of the foregoing embodiments, wherein the lens driving mechanism 20 may have a substantially polygonal structure. Specifically, the lens driving mechanism 20 and at least a wireless communicating element (such as antenna or wireless communication chip) are disposed in the housing of the electronic device, wherein the driving assembly is located adjacent to a first side of the lens driving mechanism 20 (such as the upper or lower side of the lens holder 22 in FIG. 5B), and the wireless communicating element is located adjacent to a second side of the lens driving mechanism 20 (such as the left or right side of the frame 21 in FIG. 5B).

[0048] In summary, the invention provides a lens driving mechanism and an electronic device having the same. As the frame of the lens driving mechanism comprises plastic material, it can be integrally formed in one piece, so as to greatly reduce the dimensions of the lens driving mechanism and production cost thereof. Moreover, even though the communication element (such as antenna or wireless communication chip) in the electronic device is close to the lens driving mechanism, the plastic material of the lens driving mechanism can reduce influence to the communication element, so as to facilitate miniaturization of the electronic device and ensure high performance of the communication element.

[0049] While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.