KR20130039108A - Auto focusing apparatus for three dimensional camera module - Google Patents

Abstract

PURPOSE: An automatic focusing device of a 3D subminiature camera module is provided to reduce power consumption of a battery as a continuous current supply to a coil is not necessary, thereby increasing use time for a portable device. CONSTITUTION: An automatic focusing device of a 3D subminiature camera module comprises a base(10), an actuator(30), a pair of lens carriers(50,60), a pair of pre-compressed springs(81,83), and a front cover(70). The base includes a pair of light penetration holes. The actuator is rotatably installed in the base. The pair of lens carriers is installed in the base spaced from both sides of the actuator. The actuator is installed in the base to be rotatable. The pair of lens carriers is installed in the base by being spaced respectively from both sides of the actuator.

Description

AUTO FOCUSING APPARATUS FOR THREE DIMENSIONAL CAMERA MODULE}

The present invention relates to an automatic focusing apparatus, and more particularly, to an automatic focusing apparatus applied to a small camera module capable of three-dimensional photographing provided in a small portable electronic device.

In general, portable electronic devices, for example, a mobile phone such as a smart phone is equipped with a camera module for taking pictures and moving pictures. Such a camera module tends to be manufactured in a very small size so that the size of the mobile phone does not increase in order to improve portability due to the characteristics of the mobile phone.

In addition, ultra-compact camera modules with dual charge-coupled device (CCD) cameras have been introduced to acquire three-dimensional images. This 3D micro camera module is also equipped with a dual automatic control device. Accordingly, the volume is increased compared to the camera module for two-dimensional imaging, which causes the overall volume (or size) of the small camera module as well as the small device.

In addition, the automatic focusing apparatus applied to the conventional three-dimensional miniature camera module avoids the use of a mechanical actuator and applies a voice coil actuator. For this reason, mechanical actuators were unable to avoid static-dynamic errors due to friction, mechanical deformation, and backlash associated with the operation of motors and gears, making it impossible to precisely control the focus precisely. The voice coil actuator is an actuator that uses the Lorentz force generated by the induced magnetic force of the coil in a linear motion in a static magnetic field formed by a permanent magnet, and is suitable for precisely linearly moving a relatively short distance.

However, the micro camera module applying the voice coil actuator is continuously moved to the coil in order to stop at the set position of the lens carrier corresponding to a suitable shooting distance with the subject after moving or retracting the lens carrier (the barrel) during the automatic focus adjustment. Current must be applied. This causes a lot of power consumption of the disposable battery or the rechargeable battery mounted on the portable electronic device, if the frequent shooting through the camera module has a problem that the use time of the portable electronic device is reduced.

An object of the present invention for solving the above problems is to solve the above problems The present invention is to automatically drive a pair of lens carriers through a single actuator to minimize the volume of the camera module 3D ultra compact camera module To provide a focusing device.

Another object of the present invention is to allow the lens carrier to be stopped at a predetermined position through a preload structure in a state in which the current applied to the coil is blocked during automatic focusing, thereby significantly reducing the power consumed for the automatic focusing operation. The purpose of the present invention is to provide an automatic focusing apparatus for a three-dimensional micro camera module.

In order to achieve the above object, the present invention provides an automatic focusing apparatus installed in a microscopic three-dimensional camera module for photographing a three-dimensional image, the base having a pair of light transmission holes; An actuator rotatably installed on the base; A pair of lens carriers disposed on the base at intervals on both sides of the actuator; A pair of preload springs respectively disposed in front of the pair of lens carriers to press each of the pair of lens carriers; And a front cover having an inner side supporting the pair of preload springs and detachably coupled to the front of the base, wherein the pair of lens carriers and the actuator are connected by a cam structure, and by the cam structure. According to the driving of the actuator provides an automatic focus control device characterized in that the forward or backward in the same direction at the same time.

The cam structure includes a pair of cam protrusions formed on both sides of the actuator; And a pair of cam guide holes respectively formed in the pair of lens carriers and in which the pair of cam protrusions are slidably formed.

The actuator may be a disk-shaped magnet; An arm lever fixed to one side of the magnet and having a pair of cam protrusions formed at both ends thereof; A pair of bobbins surrounding part of the arm lever and the magnet in front and rear; And it may include a coil wound on the pair of bobbins.

The pair of cam guide holes may be moved forward or backward when the pair of cam protrusions move vertically in the horizontal direction as the arm lever rotates clockwise or counterclockwise with the magnet. It is preferable that the actuator is formed to be inclined in opposite directions with respect to the actuator.

Preferably, the pair of cam protrusions are formed to be curved in contact with the pair of cam guide holes to minimize the area of contact with the pair of cam guide holes.

The actuator may further comprise a cylindrical yoke surrounding the pair of bobbins coupled. Further, the rotation angle of the magnet according to another variation changes may further include a Hall sensor disposed at a distance on one side of the yoke to detect a magnetic intensity of the magnet.

Each of the pair of preload springs, the fixing portion detachably coupled to the front end of the pair of lens carriers; A support part supported on the inner side of the front cover; And a connecting part positioned between the fixing part and the connecting part to connect the fixing part and the connecting part. In this case, it is preferable that the fixing part, the connecting part and the supporting part are sequentially arranged concentrically.

As described above, in the present invention, since a single actuator is disposed between a pair of lens carriers, and the connection structure between them is a cam structure, the pair of lens carriers can be driven simultaneously when the arm lever of the single actuator is driven to rotate. By reducing the volume of the auto focusing device, there is an advantage in that the overall volume of the compact camera module as well as the small portable device having the same can be kept compact.

In addition, the present invention, when the auto-focus control, when the current applied to the coil to block the pair of lens carriers to stop at a predetermined position, a pair of preload springs with a preload applied to the pair of lens carriers, a pair of The friction force generated between the cam protrusion and the pair of cam guide holes and the friction force generated between the plurality of guide pins and the plurality of pin guide holes of the pair of lens carriers can be stopped while maintaining the predetermined position. Accordingly, the present invention does not need to continuously supply current to the coil as in the prior art to stop the pair of lens carriers during autofocusing, which can greatly reduce the power consumption of the battery, thereby increasing the usage time of the portable device relatively. have.

1 and 2 are assembled perspective views of the automatic focusing apparatus of the 3D micro camera module according to an embodiment of the present invention viewed from the front and rear, respectively;
3 is an exploded perspective view showing the actuator shown in FIG. 1,
4 is an exploded perspective view of a state excluding the yoke of the actuator illustrated in FIG. 3;
5 is a perspective view illustrating the first lens carrier shown in FIG. 1;
6 is a front view illustrating a state in which the first and second lens carriers are advanced as the arm lever of the automatic focusing apparatus of the 3D micro camera module turns clockwise according to an embodiment of the present invention;
7 is a cross-sectional view taken along the line VII-VII shown in FIG. 6,
8 is a side cross-sectional view illustrating a first lens carrier elastically supported by a first preload spring when the first lens carrier is moved forward as shown in FIG. 6;
9 is a front view illustrating a state in which the first and second lens carriers are reversed as the arm lever of the automatic focusing device of the 3D micro camera module turns counterclockwise according to an embodiment of the present invention.
10 is a cross-sectional view taken along the line VII-VII shown in FIG. 9,
FIG. 11 is a side cross-sectional view of the first lens carrier elastically supported by the first preload spring when the first lens carrier is retracted as shown in FIG. 9.

Hereinafter, with reference to the accompanying drawings will be described the configuration of the automatic focus control apparatus of the three-dimensional compact camera module according to an embodiment of the present invention.

1 and 2, the automatic focusing apparatus of the three-dimensional compact camera module according to an embodiment of the present invention is the base 10, the actuator 30, the first and second lens carriers (50, 60) , Front cover 70, first and second preload springs 81, 83.

The base 10 has a rectangular box shape, and an accommodation groove 10a in which an actuator 30 is disposed in the center and first and second lens carriers 50 and 60 are disposed on both sides of the actuator 30, respectively, is provided. Is formed. In addition, the base 10 has first and second light passing holes 11a and 11b formed at positions corresponding to the barrel portions of the first and second lens carriers 50 and 60. In this case, the automatic focus control device of the present invention installs infrared blocking filters 13a and 13b in the first and second light passing holes 11a and 11b, respectively, to allow night photographing through the camera module. Furthermore, the base 10 has a pair of first guide pins 15a and 15b and a pair of second guides for guiding the first and second lens carriers 50 and 60 in the straight direction when they are moved forward and backward, respectively. Fins 16a and 16b protrude from the receiving groove 10a.

In addition, the base 10 is provided with a terminal 17 for electrical connection with a flexible printed circuit board (FPCB).

Referring to FIGS. 3 and 4, the actuator 30 includes a magnet 31, an arm lever 33, first and second bobbins 34 and 35, a coil 37 and a yoke 39. It includes.

The magnet 31 has a substantially cylindrical shape, as shown in FIG. 4, the S pole is magnetized on the upper side and the N pole is magnetized on the lower side.

The arm lever 33 has a coupling shaft 33a which is fixedly penetrated through the center of the magnet 31 at the center thereof, and the first and second shaft protrusions 33b, respectively, at the front and rear ends of the coupling shaft 33a, respectively. 33c) is extended. The first shaft projection 33b is rotatably supported by the coupling hole 34a of the first bobbin 34, and the second shaft projection 33c (see FIG. 7) is rotatably supported by the second bobbin 35. do. Accordingly, the magnet 31 and the arm lever 33 can operate in a clockwise and counterclockwise direction. In addition, the arm lever 33 has a cam structure in which the first and second lens carriers 50 and 60 are connected to each other, and the cam structure has a first structure according to the clockwise and counterclockwise rotation of the arm lever 33. And the second lens carriers 50 and 60 so as to be moved forward and backward at the same time. Such a cam structure will be described in detail below.

Referring to FIG. 4, the first and second bobbins 34 and 35 are coupled to surround the magnet 31 and the arm lever 33, which are previously coupled, in front and rear directions, respectively. In this case, the first and second bobbins 34 and 35 are detachably coupled to each other through the coupling protrusion 36 and the coupling groove 36a. In FIG. 4, the coupling protrusion 36 and the coupling groove 36a are shown only in the second bobbin 35, but the first bobbin 34 also corresponds to the coupling protrusion 36 and the coupling groove 36a of the second bobbin. The coupling protrusion and the coupling groove is formed.

In addition, the pair of coil winding grooves 34b and 35b to which the coils 37 are wound are formed in the first and second bobbins 34 and 35, respectively.

Referring again to FIG. 3, the yoke 39 has a substantially cylindrical shape and is made of silicon steel or pure iron. The yoke 39 has first and second bobbins 34 and 35 coupled to each other inside thereof. In this case, the yoke 39 forms through grooves 39a and 39b at both sides thereof so as not to interfere when the arm lever 33 rotates.

In this case, a hall sensor H (see FIG. 6) is disposed at one side of the yoke 39 at intervals from an outer circumferential surface of the yoke 39. The Hall sensor (H) has a different change depending on the rotational angle of the magnet 31 is changed to detect a magnetic intensity of the magnet 31. The detection signal of the hall sensor H is transmitted to a control unit (not shown) of the portable device, and the control unit advances the first and second lens carriers 50 and 60 through the detection signal of the hall sensor H. And detecting the reverse distance and controlling the driving of the first and second lens carriers 50 and 60 based on the detected value.

The first and second lens carriers 50 and 60 are formed with barrels 51 and 61 to which lenses (not shown) are coupled. In addition, the first lens carrier 50 forms a pair of parallel first pin guide holes 55a and 55b to which the pair of first guide pins 15a and 15b formed in the base 10 are slidably coupled. The second lens carrier 60 includes a pair of parallel second pin guide holes 65a and 65b in which a pair of second guide pins 16a and 16b formed in the base 10 are slidably coupled thereto. Form. In this case, the first and second lens carriers 50 and 60 are linearly disposed between the base 10 and the front cover 70 by the first and second guide pins 15a, 15b; 16a and 16b. It is arranged to be forward and backward.

In addition, the first and second lens carriers 50 and 60 have a plurality of fixing protrusions 53 and 63 for fixing the first and second preload springs 81 and 83 to the front ends of the barrel parts 51 and 61, respectively. Are each formed.

The first and second preload springs 81 and 83 are disposed between the front ends of the barrel portions 51 and 61 of the first and second lens carriers 50 and 60 and the inside of the front cover 70, respectively. 70 and the first and second lens carriers 50 and 60 serve as leaf springs for pressing the first and second lens carriers 50 and 60 in the reverse direction, respectively. The first and second preload springs 81 and 83 include fixing parts 81a and 83a, support parts 81b and 83b, and connecting parts 81c and 83c. The fixing parts 81a and 83a are detachably coupled to the plurality of fixing protrusions 53 and 63, and the supporting parts 81b and 83b are formed in a substantially circular shape and are supported on the inner side of the front cover 70. At this time, it is preferable that the support portions 81b and 83b have a size (diameter) that does not cover the through holes 71 and 73 of the front cover 70. The connecting portions 81c and 83c are formed of a metal material having the same elastic force as that of the fixing portions 81a and 83a and the supporting portions 81b and 83b and interconnect the fixing portions 81a and 83a and the supporting portions 81b and 83b. The fixing portions 81a and 83a, the connecting portions 81c and 83c, and the supporting portions 81b and 83b are arranged concentrically while gradually increasing in diameter.

When the first and the second preload spring 60 is interrupted when the current flowing in the coil 37 during the automatic focusing operation (is not limited to the interruption of the current, the first and second preload spring 60 is first The first and second lens carriers 50 and 60 are pressed in the backward direction of the first and second lens carriers 50 and 60, and the first and second lens carriers 50 and 60 are pressed into the first and second lenses. Pressing in the reverse direction of the lens carriers 50 and 60, the movement (forward or backward) of the first and second lens carriers 50 and 60 is naturally stopped by the operations described below.

That is, the first and second lens carriers 50 and 60 are caused by frictional forces generated between a portion of the inner circumferential surfaces of the first and second cam guide holes 93a and 93b and the first and second cam protrusions 91a and 91b. Can naturally stop and maintain its position. In this case, although the friction force generated by the cam structure is smaller than the friction force, that is, the first and the second guide pins 15a, 15b; 16a, 16b and each of the guide pins 15a, 15b; 16a, 16b are inserted. The frictional force generated between the plurality of pin guide holes 55a, 55b; 65a, 65b of the lens carriers 50, 60 may also be used as a force to stop the first and second lens carriers 50, 60 in the corresponding position. Can be.

Accordingly, since the current does not need to be continuously supplied to the electromagnets (or actuators) in order to stop the first and second lens carriers 50 and 60, the battery power consumption can be greatly reduced during autofocusing. Extend the operational time of the device.

The cam structure of the present invention includes the first and second cam protrusions 91a and 91b and the first and second cam guide holes 93a and 93b, and the actuator 30 (specifically, the arm lever 33). ) And the first and second lens carriers 50 and 60.

The first and second cam protrusions 91a and 91b extend at both ends of the arm lever 33, respectively, and the first and second cam protrusions 91a and 91b are slidably moved along the first and second cam guide holes 93a and 93b. Inserted into the second cam guide holes 93a and 93b, respectively. In this case, the first and second cam protrusions 91a and 91b are formed to have a curved portion so as to be able to slide smoothly along the first and second cam guide holes 93a and 93b, and preferably have a substantially cylindrical shape. Can be.

The first and second cam guide holes 93a and 93b are formed in a long hole shape formed through the first and second lens carriers 50 and 60 to be inclined at a predetermined angle, respectively (see FIG. 5). The widths of the first and second cam guide holes 93a and 93b are defined by the first and second cam protrusions 91a and 91b so that the first and second cam protrusions 91a and 91b can be slidably inserted. It is set to correspond to the diameter (or thickness).

Further, the first and second cam guide holes 93a and 93b have the same inclined angles, but their inclined directions are opposite to each other. This is to allow the first and second lens carriers 50 and 60 to move forward or backward at the same time according to the clockwise or counterclockwise rotation of the arm lever 33. That is, since the moving directions of the first and second cam protrusions 91a and 91b are opposite to each other when the arm lever 33 rotates (refer to FIG. 6, when the first cam protrusion 91a is raised, the second cam is raised). Since the projection 91b is lowered), in view of this point, the inclination directions of the first and second cam guide holes 93a and 93b are opposite to each other. In this case, the moving direction (forward or backward) of the first and second lens carriers 50 and 60 is the same as the moving direction of the arm lever 33 (or the moving direction of the first and second cam protrusions 91a and 91b). Approximately right angles.

The front cover 70 is detachably coupled to the front of the base 10 (a separate coupling structure may use a conventional snap coupling protrusion and groove), and a plurality of assembled in the receiving groove 10a of the base 10. The components (actuator 30, first and second lens carriers 50, 60) are prevented from being separated or separated from the receiving groove 10a.

The front cover 70 has first and second through holes 71 and 72 corresponding to the barrel portions 51 and 61 of the first and second lens carriers 50 and 60, respectively. In addition, the front cover 70, referring to Figure 2, the fixing projections (75a, 75b) for fixing the outside of the actuator 30 in the center of the inner side is formed, respectively to both sides of the fixing projections (75a, 75b) A plurality of fixing grooves 77a, 77b; 78a, 78b for fixing the ends of the plurality of guide pins 15a, 15b; 16a, 16b are formed, respectively.

The operation of the automatic focus control device according to an embodiment of the present invention configured as described above will be described with reference to FIGS. 6 to 11.

First, a case in which the lens is advanced during the focusing operation performed through the auto focusing device will be described with reference to FIGS. 6 to 8.

When a current is applied to the coil 37 of the actuator 30 in one direction, a force is generated between the magnet 31 and the coil 37 and the magnet 31 rotates clockwise. At this time, the arm lever 33 is rotated in the same direction as the direction in which the magnet 31 rotates. When the first and second cam protrusions 91a and 91b slide along the first and second cam guide holes 93a and 93b as the arm lever 33 rotates, the first and second lens carriers 50 60 are advanced by the same distance at the same time (see FIG. 8).

At this time, the Hall sensor (H) detects the magnetic strength of the magnet 31 that changes when the magnet 31 rotates and transmits the detection signal to a controller (not shown) of the portable device for controlling the camera module (not shown). do. Accordingly, the controller controls the operation of the actuator 30 by supplying or blocking the current to the coil 37 through the detection signal of the hall sensor H, so that the distance between the first and second lens carriers 50 and 60 is advanced. Can be controlled. For example, when the forward movement distances of the first and second lens carriers 50 and 60 are set, current is cut off in the coil 37. In this case, the first and second lens carriers 50 and 60 may be connected to the first and second cam protrusions 91a and 91b in a state where preloads of the first and second preload springs 81 and 83 are applied to the distal ends. A friction force generated between the first and second cam guide holes 93a and 93b and between the plurality of guide pins 15a, 15b; 16a and 16b and the plurality of pin guide holes 55a, 55b; 65a and 65b. The friction force causes the vehicle to stop in place and does not move forward or backward.

Meanwhile, referring to FIGS. 9 to 11, when the lens is reversed during the focusing operation performed through the automatic focusing device, the current applied to the coil 37 is applied in the opposite direction to the direction applied when the lens is advanced. Accordingly, a force in the opposite direction during the micro operation is generated between the coil 37 and the magnet 31 so that the arm lever 33 rotates in the counterclockwise direction as opposed to the lens forward, thereby the first and second lens carriers. 50 and 60 are reversed as shown in FIG. Similarly, even when the first and second lens carriers 50 and 60 are reversed, when current is cut off from the coil 37, the first and second lens carriers 50 and 60 are in place due to the above-described preload force and respective frictional forces. You can stop at.

As described above, in the present invention, the first and second preloads are cut off when the current applied to the coil 37 is cut off to stop the first and second lens carriers 50 and 60 at a predetermined position during the auto focus adjustment. The first and second cam protrusions 91a and 91b and the first and second cam guide holes 93a and the preload applied to the first and second lens carriers 50 and 60 by the springs 81 and 83. 93b) and the frictional force generated between the plurality of guide pins 15a, 15b; 16a, 16b and the plurality of pin guide holes 55a, 55b; 65a, 65b to stop a predetermined position. can do.

Accordingly, the present invention does not need to continuously supply current to the coil 37 to stop the first and second lens carriers 50 and 60 during autofocusing, thereby greatly reducing the power consumption of the battery. Relatively longer use time for portable devices.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. Various changes and modifications may be made by those skilled in the art.

10: base 15a, 15b, 16a, 16b: guide pin
30: Actuator 31: Magnet
33: Amever 34: First bobbin
35: second bobbin 37: coil
39: yoke 50: first lens carrier
55a, 55b, 65a, 65b: pin guide hole
70: front cover 81: first preload spring
83: second preload spring 91a: first cam projection
91b: second cam projection 93a: first cam guide hole
93b: second cam guide hole

Claims (9)

In the automatic focus control device installed in the ultra small three-dimensional camera module for taking a three-dimensional image,
A base having a pair of light transmitting holes;
An actuator rotatably installed on the base;
A pair of lens carriers disposed on the base at intervals on both sides of the actuator;
A pair of preload springs respectively disposed in front of the pair of lens carriers to press each of the pair of lens carriers; And
An inner side supporting the pair of preload springs and including a front cover detachably coupled to the front of the base,
And the pair of lens carriers and the actuator are connected in a cam structure, and the cam structure moves forward or backward simultaneously in the same direction according to the driving of the actuator. The method of claim 1, wherein the cam structure,
A pair of cam protrusions formed on both sides of the actuator; And
And a pair of cam guide holes respectively formed in the pair of lens carriers, the pair of cam protrusions being slidably formed. The method of claim 2,
The actuator may be a disk-shaped magnet;
An arm lever fixed to one side of the magnet and having a pair of cam protrusions formed at both ends thereof;
A pair of bobbins surrounding part of the arm lever and the magnet in front and rear; And
Automatic focusing apparatus comprising a coil wound on the pair of bobbins. The method of claim 3,
The pair of cam guide holes may be moved forward or backward when the pair of cam protrusions move up and down in a horizontal direction as the arm lever rotates clockwise or counterclockwise with the magnet. Automatic focusing apparatus characterized in that the inclined in the opposite direction with respect to the actuator to each other. 5. The method according to any one of claims 2 to 4,
And the pair of cam protrusions are curved in contact with the pair of cam guide holes to minimize the area of contact with the pair of cam guide holes. The method of claim 3,
The actuator further comprises a yoke of cylindrical shape surrounding a pair of bobbins coupled. The method according to claim 6,
And a Hall sensor disposed at intervals on one side of the yoke so as to detect a change in magnetic force of the magnet in response to a change in the rotation angle of the magnet. The method of claim 1,
Each of the pair of preload springs,
A fixing part detachably coupled to a front end of the pair of lens carriers;
A support part supported on the inner side of the front cover; And
Auto focusing apparatus comprising a; connecting portion for connecting the fixing portion and the connecting portion located between the fixing portion and the connecting portion. The apparatus of claim 8, wherein the fixing part, the connecting part, and the supporting part are sequentially arranged concentrically.

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