TWI405022B - Voice coil driving auto-focus lens module - Google Patents

Abstract

A voice coil driving auto-focus lens module combines the spring force and electromagnetic force to cooperatively control the movement of the optical lens group to carry out focus, including: a bottom cover, two conductive sheets, an insulating sheet, four permanent magnets, a sleeve barrel, an optical lens group, a coil, a spring group and an upper cover, wherein the sleeve barrel, optical lens group and the coil together form a linked lens group, and the four permanent magnets located outside the coil. The spring group contains a coil spring and a blade/leaf spring to form combined spring force. The combined spring force formed by extending and compressing the coil spring and blade/leaf spring is used to incorporate with the effect of electromagnetic force between the permanent magnets and the coil supplied with electricity so as to allow the lens group to carry out steady focus movement, thereby achieving effects of fast moving, stable focus and reducing tilt.

Description

Voice coil driving auto-focus lens module

The invention relates to an autofocus lens module driven by a voice coil motor, in particular to a focus by a balance spring force and an electromagnetic force of a spring group to control the front/rear movement of the optical lens group.

A digital camera or a camera with a shooting function has a lens module, and the function of the lens module is to drive the optical lens group to move along the optical axis to achieve autofocus and/or zoom functions. . One of the moving methods of the optical lens group is a voice coil motor (VCM), which generates an electromagnetic field by a current flowing through a coil, and the electromagnetic field and the permanent magnet generate a driving force to make the optical lens group along the optical axis. mobile. Since this method can reduce the size of the lens module, it has been widely used in small cameras, camera-equipped cellular phones or web-cameras in recent years.

A conventional voice coil motor VCM type of autofocus module is shown in FIG. 1 , such as US Patent No. 2008/0013196, US Pat. No. 6,594,450, US Pat. No. 7,145,738, Taiwan Patent No. TWM317027, and Japanese Patent No. JP 3123292, JP 3132575, which are mainly composed of a bottom cover 110 and two. Conductive sheet 122, an insulating sheet 130, four permanent magnets 140, and a lens sleeve The cylinder 150, the optical lens set 160, a coiled spring 171, a coil 180 and an upper cover 190 are formed. The lens sleeve 150, the optical lens group 160, and the coil 180 constitute a lens group that can move along the optical axis. Wherein, when the coil spring 171 is used, the coil spring 171 can generate a direct effective elastic force, so that the lens sleeve 150 can move quickly, but the use of the coil spring 171 may cause the lens group to tilt during the movement (tilt ), it is difficult to achieve extremely high precision requirements. Another conventional voice coil motor VCM type autofocus module is shown in FIG. 2, which uses the elastic force of a leaf spring 172 (blade spring, leaf spring) to move the lens sleeve 150, such as US Patent US2008/0186601, US2006. /0181632, Taiwan patent TWM331687, TWM318736, Japanese patent JP63247924 and the like. However, when the leaf spring 172 is used, the elastic force and the extension length of the leaf spring 172 are insufficient, so that the lens group moves slowly and it is difficult to meet the requirements of fast focusing; even the conventional technique uses two leaf springs 172 to compensate for the insufficient length of the movement. Disadvantages, but there is still a problem with slow movement.

For high-precision, fast-focusing requirements, the lens group can be moved at nearly constant speed during the focusing process by minimizing the range of changes in existing designs or AF modules. High precision, fast focus, and reduced tilting requirements.

The main purpose of the present invention is to provide a voice coil driving auto-focus lens module, which mainly comprises a bottom cover, two conductive sheets, an insulating sheet, four permanent magnets, and a lens cover. a cylinder, an optical lens set, a spring set, a coil and an upper cover, and the lens sleeve, the optical lens set and the coil system form a synchronously linked lens group, and the four permanent magnets are equidistant and symmetrically arranged At the periphery of the coil and at the inner corner of the bottom cover; wherein the spring assembly comprises a coil spring and a leaf spring, the coil spring is sleeved on the inner circumference or the periphery of the coil and elastically supported on the lens sleeve Between the annular outer flange and the upper cover, the inner ring of the leaf spring is fixed on one end surface of the lens sleeve, and the outer ring is kept stationary; thereby, the ring spring and the leaf spring can be different. The extension or compression of the spring of the type forms a combined spring force to match the coil after energization The electromagnetic force generated between the magnets for a long time enables the lens group composed of the lens sleeve, the optical lens group and the coil to perform stable focusing movement, thereby achieving fast moving, stable focusing and reducing tilting effect.

In order to make the present invention more clear and detailed, the following detailed description of the embodiments is as follows:

<First Embodiment>

Referring to FIGS. 3 and 4, the voice coil driving auto-focus lens module 1 of the present invention mainly comprises a base 10 and a copper plate 20 . An insulating spacer 30, a permanent magnet 40, a lens holder 50, an optical lens 60, a spring set 80, a coil 70 and a top cover 90; wherein the spring set 80 includes at least one coil spring 81 and at least one blade spring 82; and the lens sleeve 50, the optical lens set 60 and The coil 70 is composed of a lens group that can be moved synchronously, and the cymbal can be moved up/down (front/rear) between the bottom cover 10 and the upper cover 90 to achieve focusing effect.

Please refer to FIG. 5-12 again, which is a schematic diagram of the continuous combination relationship between the components of the embodiment; and FIG. 4 and FIG. 14 respectively describe the following:

Referring to Figures 4, 5 and 14, the bottom cover 10 is a rectangular frame body, and four brackets for fastening are provided at four corners for integration with the upper cover 90. A central hole 12 is formed in the center for forming an optical lens group. The optical path of 60 is provided with a plurality of positioning protrusions 13 and a spacer protrusion 14 respectively; and an IR cut-off filter 100 is disposed under the central hole 12 as shown in FIG. .

Referring to FIG. 4, FIG. 6, and FIG. 14 again, the two conductive sheets 20 are respectively fixed on the bottom cover 10 by the positioning holes 21 and are respectively disposed on the bottom cover 10, and are electrically isolated. Different electrodes are connected; and a central hole 23 is formed between the two conductive sheets 20 to correspond to the central hole 12 of the bottom cover 10.

Referring to FIGS. 4 and 7 again, the insulating sheet 30 is attached to the two conductive sheets 20 by the positioning holes 31 and the positioning holes 13 and has a central hole 32 corresponding to the central hole. 12, 23.

Referring again to FIGS. 4, 9, and 14, the four permanent magnets 40 are symmetrical and slightly arcuate, and are respectively vertically fixed to the inner side of the four brackets 11 of the rectangular bottom cover 10 to be fixed on the upper cover 90 and the bottom. Between the covers 10, in the embodiment, the four permanent magnets 40 are respectively pressed and fixed on the outer ring 822 of the leaf spring 82.

Referring again to FIGS. 4, 10, and 14, the lens sleeve 50 is disposed in the central holes 12, 23, and the inner ring 821 of the leaf spring 82 is clamped and fixed to the outer edge of the bottom end of the lens sleeve 50. The lens sleeve 50 of the embodiment is a toroidal body, and is provided with a central hole 51 and an annular outer flange 52. The optical lens assembly 60 is locked in the central hole 51 of the lens sleeve 50, and is locked. It is not limited and can be screwed or adhered.

Referring again to FIGS. 4, 11, and 14, the spring set 80 includes at least one coil spring 81 and at least one blade spring 82, wherein the coil spring 81 is sleeved with the lens sleeve 50. The outer peripheral surface is elastically supported between the annular outer flange 52 of the lens barrel 50 and the upper cover 90. As shown in FIGS. 4, 8, and 14, the leaf spring 82 of the spring set 80 is provided with an inner ring 821 and a phase connecting outer ring 822, wherein the inner ring 821 is fixed on the lens sleeve 50. The outer ring 822 is attached to the insulating sheet 30; as shown in FIG. 13, in the embodiment, the inner ring 821 can be fixedly fixed to the outer edge of the bottom end of the lens sleeve 50, and the outer ring 822 It is fixed on the insulating sheet 30 and remains stationary; and according to the structural characteristics of the leaf spring 82, the inner ring 821 and the outer ring 822 are fixed, and the inner ring 821 and the outer ring 822 are stretched (relatively displaced). The action produces an elastic force.

The lens group includes a lens sleeve 50, an optical lens group 60, and a coil 70, which are the electromagnetic force generated between the coil and the permanent magnet after being energized by the coil, the elastic force of the coil spring 81, and the elastic force of the spring force of the leaf spring 82 ( The net force produces a moving focus action. Since the coil spring 81 and the leaf spring 82 are in series as a series spring, the action is the sum of the elastic coefficients of the two, in addition to weakening the individual influence of any elastic force, the role thereof The direction can have an integral effect on the contact surface of the lens sleeve 50, which can further improve the effect of a single point generated by a single spring, and reduce the phenomenon that the lens group is tilted during the movement. Moreover, the elastic force of the coil spring 81 and the elastic force of the leaf spring 82 form a resultant force of the elastic force, which can further improve the conventional technique using only the blade. The spring 82 has the disadvantage of insufficient displacement or insufficient elastic force to move slowly.

Referring again to FIGS. 4, 12, and 14, the coil 70 is sleeved on the periphery of the coil spring 81 and fixed to the annular outer flange 52 of the lens sleeve 50 to be combined with the lens sleeve 50 to form a linkage. In this embodiment, a top ring cover 90a is further disposed below (inside) the upper cover 90, so that four permanent magnets 40 can be respectively fixed at the inner edges of the four corners of the upper ring cover 90a, and then the upper cover 90 is locked. The four brackets 11 of the bottom cover 10 are disposed such that the upper ring cover 90a is interposed between the upper cover 90 and the bottom cover 10 to assemble a lens module 1 and the four permanent magnets 40 are clamped to the inner edge of the upper ring cover 90a. There is no displacement between the face and the insulating sheet 30.

Referring to FIG. 4 and FIG. 8-14, the order of assembly between the lens sleeve 50, the optical lens assembly 60, the coil spring 81, the leaf spring 82, and the coil 70 is not limited, that is, FIG. 8-12 It is not intended to limit the assembly sequence between the components. For example, the optical lens set 60 and the coil 70 may be integrally assembled with the lens sleeve 50 (the optical lens group 60 is not shown in FIGS. 8 and 9), and the leaf spring 82 may also be First, on one end surface of the lens barrel 50, as shown in FIG. 13, the lens sleeve 50 in which the optical lens group 60, the coil 70, and the leaf spring 82 are assembled is assembled on the insulating sheet 30.

Further, the coil spring 81 of the spring group 80 can adopt a compression coil spring. When the upper cover 90 and the bottom cover 10 are integrated, the coil spring 81 can be in a proper compression state and pressed against the lens sleeve 50 downward. The spring force of the combination of the spring sets 80 stops the lens group in the lower (post) dead center position of the telescopic movement to form a telephoto position; and the head and the tail end of the coil 70 can change different electrodes and currents. In order to cooperate with the N and S poles of the permanent magnet 40 to generate an upward/downward (forward/backward) electromagnetic force, thereby driving the lens group (including the lens sleeve 50, the optical lens group 60 and the coil 70) and the leaf spring 82 The inner ring 821 moves up/down (front/rear) to perform a focusing operation; in the embodiment, the electromagnetic force between the coil 70 and the permanent magnet 40 can be generated in such a manner that only an upward (forward) electromagnetic force is generated, so that In the far focus position, the coil 70 can not pass current, so that the lens group is not affected by the electromagnetic force and stays at the lower (back) dead point position (the far focus position); when the focus operation is to be performed, an appropriate amount of current is controlled to pass through the coil 70. Generate an appropriate amount of electromagnetic force to drive the lens group up (front) Moving, is formed near focus state, when the electromagnetic force and the elastic force of the spring suffered group lens group 80 of the balance, mirror The head group stays in the adjusted position. Therefore, the lens group must be electromagnetically moved from the far focus upward (front) to the near focus position, and the spring group can be borrowed from the near focus position (downward) to the far focus position. The recovery power of 80, in order to achieve the near-focus adjustment effect.

The lens module 1 of the present invention is compared with the conventional lens module. Since the spring group 80 includes a coil spring 81 and a leaf spring 82, in addition to the series spring force, the leaf spring 82 can be utilized. Correcting the tilt phenomenon that may occur when the coil spring 81 moves, the coil spring 81 may be used to compensate the unstable spring force of the leaf spring 82; and the combined spring force and the electromagnetic force interact to enable the lens group to move quickly and stably. Reduce the phenomenon of tilting.

<Second embodiment>

Referring to FIG. 15, the lens module 1a of the present embodiment includes a bottom cover 10, two conductive sheets 20, an insulating sheet 30, four permanent magnets 40, a lens sleeve 50, an optical lens group 60, and a spring group 80. a coil 70 and an upper cover 90, wherein the spring set 80 includes a coil spring 81 and a leaf spring 82; the lens sleeve 50, the optical lens assembly 60, the coil 80 and the leaf spring 82 form a synchronously movable lens The group can be moved forward/backward (up/down) between the bottom cover 10 and the upper cover 90 to achieve focusing effect. The lens module 1a of the present embodiment is substantially the same as the lens module 1 of the first embodiment. The maximum difference between the two is that the coil spring 81 of the present embodiment is sleeved on the outer periphery of the coil 70. The coil spring 81 of the lens module 1 of the first embodiment is sleeved around the inner circumference of the coil 70.

As described above, in comparison with the conventional lens module, the lens module 1 and the 1a of the present invention can quickly and stably move the lens group and reduce the tilt phenomenon by the above-mentioned structure and the combined spring force and electromagnetic force.

The above are only the preferred embodiments of the present invention, and are merely illustrative and not restrictive. It will be apparent to those skilled in the art that many changes, modifications, and equivalents may be made without departing from the spirit and scope of the invention.

1, 1a‧‧‧ lens module

10‧‧‧ bottom cover

11‧‧‧ bracket

12‧‧‧Central hole

13‧‧‧ Positioning slightly

14‧‧‧ bump

20‧‧‧Conductor

21‧‧‧Positioning holes

22‧‧‧Trap

23‧‧‧Central hole

30‧‧‧Insulation sheet

31‧‧‧Positioning holes

32‧‧‧Central hole

40‧‧‧ permanent magnet

50‧‧‧ lens sleeve

51‧‧‧Central hole

52‧‧‧Outer flange

60‧‧‧Optical lens group

70‧‧‧ coil

80‧‧‧spring group

81‧‧‧Circle spring

82‧‧‧ leaf spring

821‧‧‧ inner circle

822‧‧‧ outer ring

90‧‧‧Upper cover

90a‧‧‧Upper ring cover

100‧‧‧Infrared filter

Figure 1 is a conventional voice coil motor VCM (using a coil spring) of the auto focus module schematic diagram.

2 is a schematic view of another autofocus module of a voice coil motor VCM (using a leaf spring).

Fig. 3 is a perspective view showing the stereoscopic combination of the first embodiment of the present invention.

Figure 4 is a perspective exploded view of the first embodiment of the present invention.

Fig. 5-12 is a schematic view showing the continuous combination relationship between members of the first embodiment of the present invention.

Figure 13 is a schematic (bottom view) view showing the assembly of the leaf spring and the lens sleeve in the first embodiment of the present invention.

Figure 14 is a side cross-sectional view showing a first embodiment of the present invention.

Figure 15 is a perspective exploded view of a second embodiment of the present invention.

1‧‧‧ lens module

10‧‧‧ bottom cover

11‧‧‧ bracket

12‧‧‧Central hole

13‧‧‧ Positioning slightly

14‧‧‧ bump

20‧‧‧Conductor

21‧‧‧Positioning holes

22‧‧‧Trap

23‧‧‧Central hole

30‧‧‧Insulation sheet

31‧‧‧Positioning holes

32‧‧‧Central hole

40‧‧‧ permanent magnet

50‧‧‧ lens sleeve

51‧‧‧Central hole

52‧‧‧Outer flange

60‧‧‧Optical lens group

70‧‧‧ coil

80‧‧‧spring group

81‧‧‧Circle spring

82‧‧‧ leaf spring

821‧‧‧ inner circle

822‧‧‧ outer ring

90‧‧‧Upper cover

90a‧‧‧Upper ring cover

100‧‧‧Infrared filter

Claims (6)

A voice coil motor-driven autofocus lens module includes a bottom cover, two conductive sheets, an insulating sheet, four permanent magnets, a lens sleeve, an optical lens group, a spring group, a coil and an upper cover, wherein The bottom cover has four brackets for fastening and is integrated with the upper cover buckle at the four corners, and a central hole is provided at the center for forming an optical path of the optical lens group, and a plurality of positioning holes are arranged at the facing corners thereof; The positioning holes are slightly matched with the positioning of the bottom cover to be fixed on the bottom cover and form an electrical isolation state, and a central hole is formed between the two conductive sheets to correspond to the central hole of the bottom cover; the insulating sheet The upper position hole is arranged to be correspondingly positioned on the bottom cover to be attached to the two conductive sheets, and a central hole is disposed thereon; the permanent magnet is a permanent magnet with a symmetrical shape and a slightly circular arc shape, respectively The inner side of the four brackets of the bottom cover; the lens sleeve is a ring body, and has a central hole and an annular outer flange; the optical lens group is fixed in the central hole of the lens sleeve; the spring group includes At least one coil spring and one leaf a spring; a coil is fixed on the annular outer flange of the lens sleeve, and the head and the tail end wires are respectively connected to different electrodes of the two conductive sheets; the upper cover is sleeved on the bottom cover and buckled and integrated; The lens sleeve, the optical lens group and the coil system form a synchronously movable lens group; wherein the coil spring is sleeved on the annular outer flange of the lens sleeve and elastically supported on the annular convex Between the edge and the inner edge of the upper cover; the leaf spring has an inner ring and a phase outer ring, wherein the inner ring is fixed on the lens sleeve and can move with the lens sleeve, and the outer ring The spring force combined with the coil spring and the leaf spring is used to match the electromagnetic force generated between the energized coil and the permanent magnet, so that the lens group can be moved in focus, thereby achieving rapid movement, Stabilizes focus and reduces tilting. The voice coil motor driven autofocus lens module as described in claim 1 The group, wherein the coil spring is sleeved inside the coil. The autofocus lens module of claim 1, wherein the coil spring is sleeved on a periphery of the coil. The voice coil motor-driven autofocus lens module according to claim 1, wherein the coil spring adopts an extended coil spring. The voice coil motor-driven autofocus lens module of claim 1, wherein the coil spring is a compression coil spring. The voice coil motor-driven autofocus lens module according to claim 1, further comprising an upper ring cover disposed below (inside) the upper cover, so that four permanent magnets can be respectively fixed on the upper ring cover. At the inner edge of the four corners, the upper cover is locked on the four brackets of the bottom cover so that the upper ring cover is sandwiched between the upper cover and the bottom cover, and the four permanent magnets are clamped on the inner edge surface of the upper ring cover and the insulating sheet. between.