TWI424255B - Lens driving apparatus - Google Patents

Description

Lens drive

The invention belongs to the technical field of camera, and particularly relates to a lens driving device.

Video cameras such as digital cameras, digital video cameras, mobile phones with camera functions, and notebook computers with cameras are usually equipped with lenses. One lens driving method commonly used in the prior art is to generate electromagnetic force by a coil and a magnet to drive the lens. Movement on the optical axis.

As shown in FIG. 1, a lens driving device of the prior art includes an iron casing 11, a magnet 12, a coil 13 and a lens frame 14, the magnet 12 and the iron shell 11 are fixed as a fixed portion, and the coil 13 is fixed to the lens frame 14. As a moving part, the moving part can move relative to the fixed part. The iron shell 11 includes an outer ring 111, an inner ring 112 and a yoke 113. The outer ring 111 and the inner ring 112 are connected by a yoke 113. The magnet 12 is fixed inside the outer ring 111, and the coil 13 is located at the inner ring 112 and the outer ring 111. There is an air gap between the coil 13 and the magnet 12, and an air gap exists between the coil 13 and the inner ring 112 of the iron shell.

The magnetic flux direction of the magnet 12 is as shown by the direction of the arrow in FIG. 1. Since the lens frame 14 is a moving portion, the inner ring 112 of the iron shell is shorter than the length of the outer ring 111 and the magnet 12, and the magnetic flux emitted by the magnet 12 is relatively small. Many parts cannot enter the inner ring 112, and the magnetic flux that this part fails to enter the inner ring encounters a large magnetic resistance, so the magnetic field of the corresponding coil part is weak, and the magnetic field utilization rate is low.

In order to solve the above technical problem, the present invention provides a lens driving device including a fixed portion, a moving portion, and a driving portion for driving a moving portion relative to a fixed portion, the fixed portion including an iron case, and the moving portion includes a lens holder for housing a lens, the driving portion comprising a plurality of magnetic groups disposed along a circumferential direction of the lens, the magnetic group being fixed to one of the iron shell and the lens frame, each magnetic group comprising at least two along the lens An axially stacked magnet, each magnet is radially polarized along the lens, and two adjacent magnets in the same group have opposite polarities, and the driving portion further includes at least one coil fixed to the other of the iron shell and the lens frame. And facing the magnetic group, the coil is wound around a winding center, the winding center is perpendicular to the lens axis, and the coil includes a plurality of portions respectively corresponding to the at least two magnets Two adjacent magnets in the same magnetic group form a magnetic circuit with two adjacent portions of the plurality of portions of the coil.

The embodiments of the present invention have the beneficial effects that since the adjacent magnets in the same group form a magnetic circuit and pass through the coil, each magnetic circuit is short and the magnetic resistance is small, so the magnetic field strength at the coil is greatly enhanced. Magnetic flux leakage is reduced, EMI (ELECTROMAGNETIC INTERFERENCE) is improved, and magnetic field utilization is increased.

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

A lens driving device provided by an embodiment of the present invention includes a fixed portion, a moving portion, and a driving portion for driving the moving portion relative to the fixed portion. The driving portion includes a plurality of magnets fixed to one of the fixed portion and the moving portion, and at least two coils are fixed to the other of the fixed portion and the moving portion and facing the magnet. For convenience of description, in the following embodiment, the magnet is fixed to the fixed portion, and the coil is fixed to the moving portion. It should be understood that the positional relationship between the magnet and the coil in the present invention is not limited thereto.

Referring to FIG. 2, the fixing portion includes a base 20, an upper cover 22, and an iron shell 24 fixed between the base 20 and the upper cover 22. The driving portion includes a plurality of magnets 26 fixed to the inner side of the iron shell. Referring to FIG. 3 and FIG. 4 together, the iron shell 24 is square, and the plurality of magnets 26 are divided into two layers along the axial direction of the lens, and are divided into four groups along the circumferential direction of the lens, and each set of magnets is respectively disposed on the iron. The four corners of the shell 24. It can be understood that the structure and positional relationship between the magnet 26 and the iron shell 24 in the present invention are not limited thereto. For example, the iron shell 24 may also be circular or other shapes, and the plurality of magnets 26 may be divided into two groups along the lens circumferential direction or Other quantities. Each magnet is radially polarized along the lens, and the magnets in the same layer have the same polarity, and the magnets in the two adjacent layers in the same group have opposite polarities.

The moving portion includes a lens frame 40 for receiving a lens (not shown), and the driving portion further includes a coil 44 fixed to both sides of the lens frame 40 along the lens axial direction, and a winding center of the coil 44 The lens is axially vertical. The coil 44 includes an upper half 44a corresponding to the upper magnet 26a and a lower half 44b corresponding to the lower magnet 26b. The coil 44 is wound into a square shape around a winding center by a winding, and is bent into a substantially cylindrical shape (see FIG. 5), and then placed outside the lens frame 40.

The magnetic flux direction of the above magnet is as shown by the direction of the arrow in Fig. 4. In each set of magnets, the magnetic flux generated by the upper magnet 26a is emitted from the N pole, and sequentially passes through the upper half 44a and the lower half 44b of the coil 44. Passing through the air gap, reaching the S pole of the same group of magnets 26b in the lower layer, and returning to the S pole of the magnet 26a through the iron shell 24. Thus, in each set of magnets, that is, in a plane parallel to the axial direction of the lens, the opposite polarity is set. Adjacent magnets together form a magnetic circuit. According to the left-hand rule, the direction of the force in the magnetic circuit formed by the upper and lower portions 44a, 44b of the coil 44 in a plane parallel to the axial direction of the lens is uniform.

In the above embodiment, two adjacent magnets in the same group together constitute a magnetic circuit and pass through the upper and lower portions of the coil. Since each magnetic circuit is short and the magnetic resistance is small, the magnetic field strength at the coil is greatly enhanced. The magnetic flux leakage is reduced, EMI (ELECTROMAGNETIC INTERFERENCE) is improved, and the magnetic field utilization rate is increased.

Referring to FIG. 6 , as another embodiment of the present invention, the moving portion may also include two semi-cylindrical coils respectively fixed to both sides of the lens frame 40 by pasting or the like, and each semi-cylindrical coil corresponds to Two sets of magnets.

Referring to FIG. 7, as another embodiment of the present invention, the moving portion may also include four arc coils, each coil corresponding to a group of magnets, and the current flowing through the four coils is in the same direction, that is, from the same direction. Look at either clockwise or counterclockwise.

In the above embodiments, the lens driving device may be approximately square, cylindrical or other shapes. Accordingly, the iron shell 24 may be approximately square, circular or other shape, and the lens frame 40 may be square, cylindrical or other shape. The plurality of magnets 26 can be divided into groups according to the shape of the iron shell and other design requirements along the circumferential direction of the lens, and the number of the coils 44 can also be adjusted. For example, the magnets can also be divided into two groups, and the coils can be one corresponding to the two. The set of magnets may also be two corresponding to the two sets of magnets.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, and improvements made within the spirit and scope of the present invention should be included in the protection of the present invention. Within the scope.

11‧‧‧ iron shell

111‧‧‧ outer ring of iron shell

112‧‧‧ inner ring of iron shell

113‧‧‧ yoke of iron shell

12‧‧‧ magnet

13‧‧‧ coil

14‧‧‧Lens frame

20‧‧‧ Pedestal

22‧‧‧Upper cover

24‧‧‧ iron shell

26, 26a, 26b‧‧‧ magnet

40‧‧‧Lens frame

44, 44a, 44b‧‧‧ coil

1 is a schematic cross-sectional view of a lens driving device provided by the prior art; FIG. 2 is a schematic exploded view of a lens driving device according to an embodiment of the present invention; FIG. 4 is a cross-sectional view of the lens driving device according to the embodiment of the present invention taken along the line AA of FIG. 3; FIG. 5 is a schematic structural view of the coil in the lens driving device according to the embodiment of the present invention; A schematic diagram of a coil structure of a lens driving device according to another embodiment of the present invention; and FIG. 7 is a schematic diagram of a coil structure of a lens driving device according to another embodiment of the present invention.

20‧‧‧ Pedestal

22‧‧‧Upper cover

24‧‧‧ iron shell

26‧‧‧ magnet

40‧‧‧Lens frame

44‧‧‧ coil

Claims (12)

A lens driving device comprising: a fixed portion including an iron shell; a moving portion including a lens frame for receiving the lens; and a driving portion for driving the moving portion to move relative to the fixed portion, the driving portion The magnetic group includes a plurality of magnetic groups disposed along a circumferential direction of the lens, the magnetic group being fixed to one of the iron shell and the lens frame, wherein the driving portion further comprises at least one coil fixed to the other of the iron shell and the lens frame, and facing The magnetic group; wherein each magnetic group includes at least two magnets axially stacked along the lens, each magnet is radially polarized along the lens, and the polarity of two adjacent magnets in the same group is opposite, the coil The winding center is perpendicular to the lens axis, and the coil includes a plurality of portions respectively corresponding to the at least two magnets, two adjacent magnets in the same magnetic group and a plurality of portions of the coil Two adjacent portions form a magnetic circuit. The lens driving device of claim 1, wherein the moving portion is located inside the fixed portion, the plurality of magnetic groups are fixed in the iron case, and the coil is fixed to the lens frame. The lens driving device of claim 1 or 2, wherein the plurality of magnetic groups comprise at least two magnetic groups, and the at least one coil is a coil corresponding to the at least two magnetic groups. The lens driving device of claim 1 or 2, wherein the at least one coil has two coils respectively fixed to both sides of the lens frame. The lens driving device of claim 4, wherein the plurality of magnetic groups are two magnetic groups respectively corresponding to the two coils. The lens driving device of claim 4, wherein the plurality of magnetic groups are four magnetic groups, and each of the coils corresponds to two magnetic groups. The lens driving device of claim 1 or 2, wherein the plurality of magnetic groups comprise four magnetic groups, the at least one coil comprising four coils distributed along the circumference of the lens, each coil corresponding to one magnetic group. The lens driving device of claim 7, wherein the iron shell is square, and the four magnetic groups are respectively fixed to the four corners of the iron shell. The lens driving device of claim 1, wherein the coil is curved in an arc shape before being fixed to the lens frame. The lens driving device of claim 9, wherein the coil is fixed to the outer periphery of the lens frame by a bonding method. A lens driving device comprising: a fixed portion including an iron shell; a moving portion including a lens frame for receiving the lens; and a driving portion for driving the moving portion to move relative to the fixed portion, the driving portion The magnetic group is disposed in the circumferential direction of the lens, the magnetic group is fixed to the iron shell, and the driving portion further includes a coil fixing sleeve disposed outside the lens frame, wherein the coil corresponds to the plurality of magnetic groups; Each magnetic group includes at least two magnets axially stacked along the lens, each magnet being radially polarized along the lens, the opposite polarity of two adjacent magnets in the same group, the winding center of the coil and the lens axial direction Vertically, the coil includes a plurality of portions respectively corresponding to the at least two magnets, and two adjacent magnets in the same magnetic group form a magnetic circuit with two adjacent portions of the plurality of portions of the coil . A lens driving device comprising: a fixed portion including an iron shell; a moving portion including a lens frame for receiving the lens; and a driving portion for driving the moving portion to move relative to the fixed portion, the driving portion The sub-group includes a plurality of magnetic groups disposed along a circumferential direction of the lens, the magnetic group is fixed to the iron shell, and the driving portion further includes a plurality of coils corresponding to the magnetic group, the coils being distributed along the circumferential direction of the lens and fixed to the The outer side of the lens frame; wherein each magnetic group includes at least two magnets axially stacked along the lens, each magnet is radially polarized along the lens, and the polarity of the two adjacent magnets in the same group is opposite, and the coil is wound The center of the line is perpendicular to the axial direction of the lens, and the coil includes a plurality of portions respectively corresponding to the at least two magnets, two adjacent magnets in the same magnetic group and two of the majority of the coil Adjacent portions form a magnetic circuit.