JP2008145597A - Auto-focusing actuator of camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve reductions in size and weight as well as power consumption by simultaneously moving a lens section and a driving section during the operation of a camera module and by driving a non-contact system and a cam system together. <P>SOLUTION: The auto-focusing actuator of the camera module 10 includes: a lens section 20 for capturing the video information of a subject; a driving section 30 connected to the lens section and serving to move the lens section upward or downward; and a lens barrel 40 in which the lens section and the driving section are installed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, the camera module for a mobile phone is mechanically coupled with a lens unit and a drive unit, and is driven by using both a non-contact method and a cam method, thereby greatly reducing power consumption and downsizing. The present invention relates to a new autofocus actuator that can realize weight reduction.

In general, the camera module in a broad sense includes CCM (Compact Camera Module) components used in various electronic devices such as PDAs, PC cameras, small surveillance cameras, and robot vision. The camera module includes an imaging optical system, an image sensor that converts the focused light into an electrical signal, an ISP (Image Signal Processor) that converts the electrical signal into an image signal, and a PCB that transfers the image signal to the back-end chip. And FPCB (Flexible Print Circuit Board). The optical system is subdivided into a lens, a lens barrel, and an infrared blocking filter, and in the case of a high pixel module, includes an optical zoom, auto focus, and a shutter. The ISP is usually built in the PCB together with the image sensor, but it is separated from the image sensor at high pixels. CMOS image sensors (CIS) and CCDs are used as camera image sensors. For example, CCDs dominate high-image camera modules for mobile phones. The CCD auto-focusing mechanism employs a mechanism for focusing by moving a lens using a stepping motor, a piezoelectric motor, a VCM (Voice Coil Motor), or the like. There are two types of auto-focusing: an active method that detects the distance by applying light or ultrasonic waves to a subject, and a passive method that moves the lens so that the best image can be obtained by analyzing the frequency component of the image output signal. In general, a passive camera module is used for a mobile phone, and the lens is moved in response to a direction signal and a focus drive signal. The amount of movement at that time is generally about 0.3 mm.

The optical zoom has a function of changing the magnification of an image by combining a plurality of lenses and adjusting the focus distance and angle of view (field width) of the lens group without changing the focus. It consists of a lens and a drive mechanism. The optical zoom is fixed independently to the lens barrel and operates while changing the distance between the lenses. The first group lens Variator determines the size of the subject imaged on the image sensor, and the second group lens compensator corrects the optical order in conjunction with the Variator. The focus, which is the last lens group, plays a role of focusing on the sensor surface according to the distance from the subject.

  The method using a stepping motor in the auto-focusing mechanism is a mechanical drive system that rotates by a predetermined step unit by giving a pulse signal. Although this method consumes less power when the motor is stopped, there are problems that vibration and noise occur during operation, and that the price increases as the size is reduced. The method using a piezoelectric motor is a method of driving by converting simple vibrations of a piezoelectric ceramic into linear motion. This method consumes less power during operation, but has a large error and a high price. (See, for example, Patent Document 1)

VCM is a system that directly moves the lens barrel by passing current through the coil between the electrodes. It has excellent characteristics in terms of price, small size, and power consumption, and is widely used, but it also has the disadvantage of large errors. . In recent years, portable terminal devices have been rapidly spread, and the more expensive ones are equipped with various functions such as MP3 music, wireless Internet, camera, video, and TV reception. In order to achieve battery operation for a long time, there is an increasing need for lower power consumption, lighter weight, and smaller size of system components. (For example, see Patent Document 2 etc.)
JP 2004-004253 A JP 2006-154511 A

  In the present invention, since the structural review of the drive system was attempted in order to solve the problem of accuracy of the conventional product, the present invention mechanically arranges the lens unit and the drive unit for the camera module for mobile phones. Provided is a new autofocus actuator that can be combined and driven in combination with a non-contact method and a cam method to significantly reduce power consumption and to achieve a reduction in size and weight.

In order to achieve this object beforehand, the present invention has the following configuration.

An autofocus actuator of a camera module according to the present invention includes a lens unit that acquires video information of a subject; a drive unit that is coupled to the lens unit and moves the lens unit up and down; and the lens unit and the drive unit are installed. It is characterized by including a lens barrel.

The lens barrel further includes a PCB (Printed Circuit Board), and the driving unit is configured such that the coil that inherits the electrical signal rotates horizontally by a pair of magnets, and the horizontal motion moves vertically. It is configured to include a cam that converts to

On the other hand, the drive unit includes a pair of magnets orthogonal to the lens barrel and a coil between the magnets, and the drive unit includes cam protrusions arranged at equal intervals around the circumference, The cam protrusion includes a guide recess provided at an opposing position. The cam further includes a horizontal arm, and at least one of the pair of magnets is provided with a guide recess.

The cam is configured to surround a coating layer that surrounds an outer peripheral surface thereof. The cam is interlocked with the cam, the lens unit further includes an elastic elastic body, and the coil and magnet of the drive unit are non-contact type. (VCM-VoiceCoil Motor).

The coil is preferably wound around the horizontal arm (Fixing Rolling Type) so that the coil can be rotated horizontally within 180 degrees from the magnet.

In the present invention, when the camera module is operated, the lens unit and the drive unit are interlocked with each other, and the non-contact method and the cam method are combined to drive. is there.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1 or FIG. 2, the camera module (10) includes a lens unit (20), a drive unit (30), and a lens barrel (40).

The lens unit (20) acquires video information of a subject, performs data processing by the same image sensor as a CCD or CMOS included therein, and transfers the information through the PCB. The lens unit (20) uses a conventional general technique, and a detailed description thereof will be omitted here.

  The drive unit (30) includes a pair of magnets (31a, 31b), a coil (32), a cam (34), a lens housing (35), and an elastic body (36).

The magnets (31a, 31b) have a predetermined polarity (N polarity or S polarity), the upper magnet (31a) is coupled to the housing, and the lower magnet (31b) is a mirror. Connected to the tube (40).

The coil (32) is wound around the horizontal arm (343) in the driving unit (30) with a certain pattern (Fixing Rolling Type), and is not in contact between the magnets (31a, 31b). In the outside, it is linked with the magnet by an electrical signal. At this time, when the magnets (31a, 31b) are fixed on the lens barrel, by setting the angle of the curved surface to 180 degrees, the coil can be prevented from being detached, and the range of motion of the cam protrusion (341) can be reduced. Will be able to decide.

  The cam (34) surrounds a cam shaft (341), a cam projection (342) and a horizontal arm (343), and the cam shaft (341) is coupled to the lens barrel (40) in a donut shape. Is done. The cam protrusions (342) are provided in the form of four protruding at the same interval on the upper surface of the cam shaft (341). The horizontal arm (343) is positioned on the side surface of the cam shaft (341), and is positioned between the magnets (31a, 31b) in a state where the coil (32) is wound. The lens barrel (40) is equivalent to the base of the camera module (10), and subject information acquired from the lens unit (20) through the lens barrel (40) is transferred to the PCB (40) positioned on the lens barrel (40). Printed Circuit Board) is used to transfer to the outside.

  Here, as mentioned in the prior art, the drive unit (30) adopts a non-contact type VCM (VoiceCoil Motor) that consumes less power than a contact method (stepping motor, piezoelectric motor). Thus, the horizontal rotational motion by the magnet and the coil is transmitted to the cam (34), and the lens portion (20) can be moved vertically from the cam (34).

  Or the said drive part (30) can minimize the frictional force which can be generate | occur | produced with a cam (34), and can prevent wear by making the outer periphery of a cam (34) into a coating layer.

  In this way, through the same concept as described above, the amount of power consumed by the drive unit (30) can be reduced, and at the same time, the weight and size can be reduced.

The coupling relationship of the present invention will be described with reference to the accompanying drawings. The cam (34) is seated on the upper part of the lens barrel (40) while the lens barrel (40) is positioned at the lower part. Here, the cam (34) is in a state where the coil (32) is wound around the horizontal arm (343). The coil (32) is coupled to the lens barrel (40) and fixed in a position isolated on the magnet (31b), and the magnet (31a) is isolated on the coil (32). Fix the position in the touched state. In addition, in order to fix the lens housing (35) on the cam (34), a guide recess (351) formed in the lens housing (35) is combined with the cam projection (342) and positioned. Then, the elastic body (36) is inserted into the lens housing (35), the lens portion (20) is inserted into the lens housing (35), the position is fixed to the lens barrel, and then the housing is used. The elastic body (36) may be pressed with blotting paper.

  Hereinafter, the operation state of the autofocus actuator of the camera module of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 3a to 3c, the coil (32) is actuated by a magnetic force between the magnets (31a, 31b) that has received an electrical signal from the outside. ) Moves through the lens unit (20) with reference to the acquired subject information. If the coil (32) moves horizontally on the magnet according to the acquired subject information, the cam (34) receives the horizontal rotation of the coil and rotates the cam shaft (341). Thus, the cam projection (342) formed on the cam shaft (341) moves according to the guide recess of the lens housing (35). At this time, the guide recess (351) has an inclined surface, and as the cam protrusion (342) moves, the lens housing (35) is vertically moved upward or downward to move the lens housing (35). The combined lens part (20) is interlocked. Then, by using the elastic body (36), the lens housing (35) moved up and down is pressed, and the lens housing lifted up is pushed down to reduce the consumed electric power during the up-and-down operation. You can make it. As described above, it is unnecessary to move the drive unit through the information of the subject obtained by the lens unit (20) and cause the lens unit (20) to check with this, and the lens unit (20) focuses on the subject. Space can be minimized, further reducing weight and size.

    FIG. 4 or FIG. 5 is another embodiment according to the present invention. Referring to FIG. 4 or FIG. 5, a curve centering on the cam shaft (341 ′) having the circumference of the magnet (31a ′, 31b ′) is shown. And provided perpendicularly from the upper surface of the lens barrel (40 ′). At this time, the magnets (31a ′, 31b ′) are divided into an inner magnet (31b ′) and an outer magnet (31a), and the magnets (31a ′, 31b ′) are arranged between the magnets (31a ′, 31b ′). The coil (32) having the same shape as the curved surface is provided, and the space between the outer magnet (31a ') and the inner magnet (31b') can be guided. At this time, the VCM method which is a non-contact method is adopted as described above. Then, a guide recess (37) cut through the inner surface of the inner magnet (31b ') is formed, and the horizontal arm (343') moves according to the guide recess, and at the same time, an operating range by the guide recess is proposed. can do. In this way, the same effect as described above can be obtained.

As described above, the present invention is not limited to the above-described embodiments, and various modifications and changes may be made by those skilled in the art, which are defined in the appended claims. It is included in the spirit and scope of the invention.

For camera modules used in various electronic devices such as PDAs, PC cameras, small surveillance cameras, and robot visions, the lens unit and the drive unit are mechanically coupled and driven using both the non-contact method and the cam method. As a result, power consumption can be greatly reduced, and miniaturization and weight reduction can be realized.

It is the perspective view which showed the autofocus actuator of the camera module. It is a disassembled perspective view which shows the auto-focus actuator of a camera module. a is a side view showing an operating state of an autofocus actuator of a camera module. b is a side view showing the operating state of the autofocus actuator of the camera module. c is a cross-sectional plan view showing the operating state of the autofocus actuator of the camera module. It is the perspective view which showed the other Example by the auto-focus actuator of a camera module. FIG. 5 is a cross-sectional plan view illustrating an autofocus actuator of the camera module illustrated in FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Camera module 20 Lens part 30 Drive part 31a, 31b Magnet 32 Coil 34 Cam 35 Lens housing 36 Elastic body 37 Concave part 40 Lens barrel 341 Cam shaft 342 Cam protrusion 343 Horizontal arm 351 Guide concave part

Claims (12)

A lens unit that acquires video information of an object; a driving unit that is coupled to the lens unit and moves the lens unit up and down; and a lens barrel that includes the lens unit and the driving unit. An autofocus actuator for the camera module. The autofocus actuator of a camera module according to claim 1, wherein the lens barrel further includes a PCB (Printed Circuit Board). 2. The drive unit according to claim 1, wherein a coil whose electrical signal has been confirmed includes a cam that horizontally rotates by a pair of magnets and a cam that changes the horizontal motion to a vertical motion. An autofocus actuator for the camera module described in 1. The camera module autofocus actuator according to claim 3, wherein the cam further includes a horizontal arm. 4. The drive unit according to claim 3, wherein the drive unit includes cam protrusions arranged at equal intervals around a circumference, and guide recesses provided at positions facing the cam protrusions. Auto focus actuator for camera module. The camera module autofocus actuator according to claim 1, wherein the driving unit includes a pair of magnets orthogonal to the lens barrel and a coil positioned between the magnets. The autofocus actuator for a camera module according to claim 6, wherein at least one of the pair of magnets further includes a guide recess. The autofocus actuator of a camera module according to claim 6, wherein the cam further includes a coating layer surrounding an outer peripheral surface thereof. 8. The camera module autofocus actuator according to claim 7, further comprising an elastic body that is interlocked with the cam and supports the elasticity of the lens portion. 4. The camera module autofocus actuator according to claim 3, wherein the coil is wound around the horizontal arm. 11. The autofocus actuator of a camera module according to claim 1, wherein the coil and magnet of the driving unit are configured in a non-contact manner (VCM-Voice Coil Motor). 11. . The magnet is configured so that the coil rotates horizontally within 180 degrees.
The autofocus actuator of the camera module according to claim 1.

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