CN102455478B - Automatic focusing mechanism - Google Patents

Abstract

A kind of automatic focusing mechanism, it realizes focusing for driving camera lens module to move, and described camera lens module has optical axis, and described automatic focusing mechanism comprises: a fixed mount, and it has the receiving space of central shaft and optical axis coincidence, and described fixed mount has breach; One movable piece, it is arranged in receiving space and also can moves in receiving space, and described movable piece has the through hole of central shaft parallel optical axis, and the position described movable piece having through hole corresponding is provided with tangent plane; One supporting body, it matches with fixed mount for accommodating movable piece; One guide rod, it is located in through hole, and two ends are separately fixed on fixed mount and supporting body; One piezo-electric motor, it to be fixed in breach and to abut tangent plane, and the deformation quantity that described piezo-electric motor has parallel optical axis moves under the guiding of guide rod for driving movable piece.

Description

autofocus device

technical field

The invention relates to an automatic focusing device.

Background technique

A digital camera or a mobile phone with a shooting function is equipped with at least one lens module, and the function of the lens module is to drive the optical lens or the optical lens group to move along the optical axis to achieve auto-focus and/or zoom functions.

One of the moving methods of the optical lens group is a voice coil motor, which generates an electromagnetic field by flowing current through the coil, and the electromagnetic field and the permanent magnet generate a driving force to move the optical lens group along the optical axis. Because this method can reduce the size of the lens module, it has been widely used in compact cameras, mobile phone cameras or network cameras in recent years.

Although the volume of the lens module can be reduced by using the voice coil motor to drive the focusing or zooming, the quality of the lens module is relatively high due to the use of permanent magnets.

Contents of the invention

In view of this, it is necessary to provide an automatic focusing device with simple structure and low mass.

An automatic focusing device, which is used to drive a lens module to move to achieve focusing. The lens module has an optical axis. The automatic focusing device includes: a fixed frame, which has a storage space where the central axis and the optical axis coincide. There is a notch on the fixed frame; a movable part, which is arranged in the receiving space and can move in the direction parallel to the optical axis in the receiving space, the movable part has a central axis parallel to the The through hole of the optical axis has a cut surface at the position corresponding to the through hole on the movable part; a carrier, which cooperates with the fixed frame to accommodate the movable part; a guide rod , which is installed in the through hole, and the two ends are respectively fixed on the fixing frame and the carrier; a piezoelectric motor, which is fixed in the gap and abuts against the cut surface, the piezoelectric motor A deformation amount parallel to the optical axis is used to drive the movable member to move under the guidance of the guide rod.

Compared with the prior art, the movable part of the embodiment of the present invention moves along the guide rod driven by the deformation of the piezoelectric motor. Since the autofocus device does not use a magnet with a large mass, the magnet used in conjunction with the magnet is also omitted. Coil, so that the mass of the autofocus device is small.

Description of drawings

FIG. 1 is a schematic diagram of an autofocus device according to an embodiment of the present invention.

Fig. 2 is an exploded view of the autofocus device according to the embodiment of the present invention.

Description of main component symbols

Autofocus device 10

Fixture 11

First containment space 110

Notch 111

first through hole 112

Movable parts 12

Second containment space 120

Facets 121

Through hole 122

first groove 123

Carrier 13

Clear hole 130

Blind hole 131

Positioning column 132

guide rod 14

Piezo motor 15

Holder 16

Attraction rod 17

circuit board 18

detailed description

The embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to Fig. 1 and Fig. 2, the autofocus device 10 provided by the embodiment of the present invention is used to drive the movement of the lens module (not shown) to realize the focusing operation. , a carrier 13 , a guide rod 14 , a piezoelectric motor 15 , a holder 16 , an attraction rod 17 and a circuit board 18 .

The circuit board 18 is used to provide electrical energy to the piezoelectric motor 15 to make it work. When the circuit board 18 supplies current to the piezoelectric motor 15, the piezoelectric motor 15 has mechanical deformation, and the current in different directions has different mechanical deformation.

The fixing frame 11 has a square structure with a first receiving space 110 for receiving the movable element 12 , and the central axis of the first receiving space 110 coincides with the optical axis of the lens module. One corner of the fixing frame 11 has a first through hole 112 whose central axis is parallel to the optical axis of the lens module, and the other corner with the first through hole 112 located on the diagonal line has a gap 111 for accommodating the holder 16, the holder 16 is used to fix the piezoelectric motor 15 in the notch 111 .

Of course, the first through hole 112 and the notch 111 may not be arranged on a diagonal line, but may be arranged on a straight line passing through the central axis of the first receiving space 110 .

The movable part 12 is movably arranged in the first storage space 110. The movable part 12 is a square structure with a second storage space 120 whose central axis coincides with the optical axis of the lens module. The second storage space 120 is used to accommodate The lens module, so that the lens module moves up and down along the optical axis driven by the movable member 12 to realize the focusing operation.

Corresponding to the first through hole 112 on the fixed frame 11 , a second through hole 122 parallel to the optical axis of the lens module is formed on one corner of the movable member 12 . There is a tangent surface 121 on the corner opposite to the second through hole 122 of the movable member 12, the tangent surface 121 has a first groove 123 whose length direction is parallel to the optical axis of the lens module, and the attracting rod 17 is fixed in the first groove 123 Inside and protruding from the first groove 123 .

The holder 16 fixes the piezoelectric motor 15 in the notch 111 of the fixing frame 11 and makes the piezoelectric motor 15 abut against the attracting rod 17 .

Of course, the attraction rod 17 may also be omitted, and the piezoelectric motor 15 may directly abut against the cut surface 121 .

The carrier 13 is also a square structure, and its geometric center has a light hole 130 for allowing the light passing through the lens module to enter the image sensor on the carrier 13 for imaging. The four corners of the supporting body 13 respectively have a positioning post 132 , which cooperates with the positioning holes (not shown) on the fixing bracket to fix the supporting body 13 on the fixing bracket 11 .

There is a blind hole 131 on one corner of the carrier body 13, the guide rod 14 is penetrated in the second through hole 122, and the opposite ends of the guide rod 14 are respectively located in the first through hole 112 and the blind hole 131, and are located in the first through hole 131. Parts in the through hole 112 and the blind hole 131 can be fixed on the fixing frame 11 and the carrier 13 by dispensing glue, so that the movable part 12 moves up and down in the first receiving space 110 under the guidance of the guide rod 14 .

When the circuit board 18 provides current to the piezoelectric motor 15, the piezoelectric motor 15 can convert the input electric energy into its own deformation, which has a component parallel to the optical axis of the lens module, and the deformation component makes the piezoelectric motor 15 and the attraction There is a relative displacement between the rods 17. Since the piezoelectric motor 15 is fixed on the fixed frame 11 and cannot move, the movable member 12 can move along the guide rod 14 in the first accommodation space 110 of the fixed frame 11 under the drive of the deformation component. The inside moves up and down, so that the lens module realizes the focusing operation under the drive of the movable member 12 .

In addition, the auto-focus device 10 does not use a magnet with a large mass, thereby also omitting the coil used in conjunction with the magnet, so that the auto-focus device has a small mass and a simple structure.

It can be understood that those skilled in the art can also make other changes within the spirit of the present invention for the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims (5)

1. An autofocus device, which is used to drive the camera lens module to move to focus, the lens module has an optical axis, and the autofocus device includes: A fixed frame, the fixed frame is a square structure, it has a receiving space where the central axis coincides with the optical axis, there is a gap and a first through hole on the fixed frame, and the first through hole is located on the fixed frame A corner of , the position where the notch is located is diagonal to the position where the through hole is located; A movable part, which is arranged in the receiving space and can move in the receiving space along a direction parallel to the optical axis, the movable part has a second through hole whose central axis is parallel to the optical axis, The position of the second through hole corresponds to the position of the first through hole, and a cut surface is provided on the movable member at a position diagonal to the second through hole, and the cut surface has a longitudinal direction parallel to the optical axis of the lens module the first groove of a carrier, which cooperates with the fixed frame to accommodate the movable part; a guide rod, which passes through the second through hole, and its two ends are respectively fixed on the fixing frame and the carrier; a suction rod fixed in the first groove and protruding from the first groove; and A piezoelectric motor, which is fixed in the notch and abuts against the attraction rod, the piezoelectric motor has a deformation parallel to the optical axis and is used to drive the movable member under the guidance of the guide rod sports. 2 . The autofocus device according to claim 1 , wherein the carrier has a blind hole and the other end of the guide rod is fixed in the blind hole. 3 . 3. The auto-focus device according to any one of claims 1-2, characterized in that the auto-focus device further comprises a holder, and the holder is used to fix the piezoelectric motor in the notch. 4. The auto-focus device according to claim 3, further comprising a circuit board, the circuit board is fixed on the holding unit and electrically connected to the piezoelectric motor. 5. The autofocus device according to claim 3, wherein the opposite end faces of the fixing frame and the carrier have positioning holes and positioning posts respectively, and the positioning holes and the positioning posts cooperate to make the carrying body The body is fixed on the fixed frame.