KR20090048683A - Linear motor of lens focus and its control method - Google Patents

Abstract

The present invention relates to a linear motor for controlling the focal length of a lens, in which the dead zone of magnetic flux density is greatly reduced by changing the structure of the permanent magnet in the lens focal length controlling linear motor so that the total number of components and dimensions are reduced. The core and the stopper installed in the coil allow the moving object to be fixed in position even though no current is supplied to the coil, thereby greatly reducing the power consumption of the camera.

AF (Auto Focus), Pulse Width Modullation (PWM), Pulse Density Modullation (PDM), Pulse Amplitude Modullation (PAM), Full bridge circuit, magnetic flux density, lens, permanent magnet, coil, linear motor

Description

Linear motor for lens focal length control and control method {Linear Motor of lens focus and its control method}

The present invention is applied to a camera module (lens module, actuator, image sense or image sense process, driving circuit applied to an optical device (camera, camcorder, camera mobile phone, etc.) that requires auto focus and zoom (Zoom) , Which consists of F-PCB, PCB, or connector), and mounts the lens and moves the lens according to the control signal from the control source of the optical device. It relates to a linear motor for controlling the focal length of the lens to improve the effect, quality and performance.

Camera modules (lens modules, actuators, image sense or image sense processes, drive circuits, F-PCBs or PCBs, connectors, etc.) applied to optical devices (cameras, camcorders, mobile phones, etc.) that require auto focus and zoom. The linear motor (actuator) that moves the lens to one component of the lens is configured to move the lens mounted on the moving object by a control signal from a control source so that an appropriate image can be formed on the sensor or film according to the distance of the subject. To move or stop.

Looking at the actuator operation of the linear motor for controlling the focal length of the camera lens which is conventionally used as a conventional technology of such a linear motor, the correlation between the restoring force according to the elastic modulus of the leaf spring and the magnetic coupling force between the stationary magnet and the induction magnet (coil) (two If there is a difference in force, the lens installed in the moving body including the guide magnet (coil) moves between two vertices on the optical axis of the fixture including the stator magnets, and if the two forces are balanced, Keep stationary in position.

Looking at the operation of the driving circuit for driving a linear motor using such a leaf spring, the PWM signal supplied from the control source is integrated through an integrator or applied to the input of the operational amplifier using a digital-to-analog convert (DAC). The output signal through the amplifier is controlled by the control signal of the BJT or FET to change the switching resistance value of the BJT and FET according to the control signal. It is a circuit.

However, such a conventional focal length control linear motor must always apply a current to the coil in order to focus, so that an optical device using a battery (camera, camcode, camera phone, surveillance and reconnaissance camera, robot, notebook, PMP) , PDA, etc.), the conventional linear motor actuator is applied to reduce the battery use time.

As a prior art for solving the current consumption problem, which is a problem of the prior art, the present applicant installs a cylindrical body by spaced apart at regular intervals to the outer circumference of the movable body in which the lens is installed in Korea Patent No. 10-0719799, and the movable body is Alternatively, a technique has been proposed for a drive circuit using an actuator of a solenoid linear motor having a permanent magnet, a coil, and a stopper selectively mounted on a fixed body and a variable voltage source for driving the actuator of the linear motor.

This conventional technology solves the problem of power consumption because it does not need to apply current to the coil when stopped by the mutual operation of the coil, the stopper and the permanent magnet, but the number of components constituting the actuator, the structure is complicated, precision processing and assembly This necessitates an increase in the production cost of the actuator, which causes a decrease in reliability of the component and a poor quality. In addition, since all the components constituting the permanent magnet and the coil, the moving body and the fixed body must be newly manufactured when changing the component parts such as the lens, the design change is not easy, and there is a problem in that a large cost and time are consumed when the design is changed.

In addition, the thick thickness caused problems for application in thinner systems (especially cell phones).

In addition, since a variable voltage source is used, the control method by the control source has a complicated problem.

An object of the present invention for solving the above problems is to modularize the key components into a component and to place the component or component in one space of the linear motor for controlling the focal length of the lens to reduce the production cost and improve the quality, design changes It is easy and convenient to develop new products, and the structure of the permanent magnet is changed to solve the magnetic flux distributed to other spaces other than the space where the non-linearity or non-uniformity of magnetic flux density distribution and the magnetic coupling force will be concentrated. By reducing the dead zone of magnetic flux density, the moving distance of the linearly controllable moving object is increased, and the current flowing through the coil is concentrated by focusing on the ferromagnetic bracket attached to the back of the permanent magnet and the core and stopper, which are attached to the coil. Reduces the power consumption of the optical system By applying a constant voltage source that can be turned on and off, a simpler control algorithm can be applied at the control source to find the focal length of the lens required for a proper image on the sense or film according to the distance of the subject. The purpose is to.

Features of the present invention for achieving the above object is a coil structure comprising a coil constituting a moving body or a stationary body and a permanent magnet structure comprising a permanent magnet, receiving an operation control signal from the control source to the coil operating operation signal In the linear motor for controlling the focal length of the lens, which includes an output drive circuit, and an injection molded product in which the coil structure and the permanent magnet structure are installed, the coil structure includes a magnetic core in the center of the coil and is configured as a stop. The permanent magnet structure is characterized in that formed by installing a bracket made of a ferromagnetic material on the opposite side of the coil of the permanent magnet.

In the above configuration, the permanent magnet is formed as a quadrangle having a small thickness to symmetrically magnetize the N pole and the S pole symmetrically to the diagonal line connecting two vertices, and the permanent magnet magnetized on the diagonal line is a diagonal line. The dichotomous shape is formed along the dichotomy, and the dichotomous permanent magnets are changed so that the positions of both ends are different while the diagonals are engaged, or the diagonal parts are spaced apart from each other, and the separation space is formed as the shape of the permanent magnet by inserting an empty space or a nonmagnetic material. By combining with the bracket, two permanent magnets, the bracket, a permanent magnet structure composed of a non-magnetic material of the space-space shape.

In addition, a stopper made of a ferromagnetic material is further provided to the outside of the coil. In addition, by outputting a control signal using a constant voltage source capable of turning on / off the output voltage to the coil of the actuator including the permanent magnet structure and the coil structure, the control source can control the distance of the subject by a simpler control method. To focus the lens accordingly.

In addition, the present invention provides a method for automatically adjusting the focal length of a lens in a short time by applying various control algorithms to be described in the detailed description of the present invention.

According to the present invention, the linear motor for lens focal length control of a linear motor for lens focal length control is formed by densely arranging a space for mounting the core parts and components in one side of the fixed and moving object injections in the lens focal length control linear motor constituting the camera. The number of components can be reduced, the structure can be simplified, the quality can be improved, and the production cost can be reduced, and the specification can be easily changed, the new product can be developed, and the use of one mobile body with more than one mobile body can be easily changed.

In addition, by changing the structure of the permanent magnet to reduce the dead zone of the magnetic flux density to increase the moving distance of the linearly controllable moving object, the separation of the permanent magnets based on the same moving distance conditions the lens focus compared to the conventional configuration There is an effect of reducing the thickness of the linear motor for distance control.

In addition, the magnetic coupling force is counted due to the strength of the magnetic flux directed toward the coil boundary by the bracket, which is a ferromagnetic material attached to the rear of the permanent magnet, and the stopper, which is attached to the back of the coil, based on the coil boundary. As a result, the current flowing through the coil can be reduced as compared with the prior art, thereby reducing the power consumption of the portable optical device, thereby increasing the battery usage time.

Furthermore, by applying a constant voltage source that can be turned on and off and applying a control algorithm to the driving circuit, a simpler control method can be automatically focused in a shorter time, and the faster the focus, the more the power consumption of the optical device is increased. It has the effect of reducing it.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a schematic configuration of a linear motor for controlling a lens focal length according to the present invention.

The linear motor for controlling the focal length of a lens according to the present invention includes a coil 3 wound in an elliptical shape on one side, a core 2 made of a magnetic body fitted in the center of the coil 3, and the coil 3. And a stopper (1) installed on the outer circumferential surface of the core (2) to determine the position of the coil (3) and linearizing the magnetic flux density, and a permanent magnet (4) for moving the moving body by working with the coil (3). Bracket 21 which is installed on the opposite side of coil 3 of permanent magnet 4 to reduce dead zone of magnetic flux density and further strengthens the intensity of magnetic flux with coil 3, and control signal from control source 31. It is composed of a drive circuit that is applied to output the operation drive signal to the coil (3).

In the above configuration, the stopper 1 allows the insertion hole 118 into which the core 2 is inserted at the center thereof, as shown in FIGS. 2A and 2B, or to both sides as shown in (b). The fixing wall 120 fixing the both sides in the long axis direction of the coil 3 is bent to protrude, or the insertion hole in which the core 2 is fixed as shown in (c) is not perforated, but the two sides in the long axis direction of the coil 3 are not drilled. While fixing, the bent surface 121 bent in double to fix the coil boundary surface 25 side is formed, or another bending to be bent toward the injection molding mounting space in which the coil structure is to be mounted as shown in (d) to fix the stopper 1. Forming the surface 127 or supporting the vertical direction to the coil boundary surface 25 to form a bent surface 126 to prevent the separation of the coil 3, thereby preventing the separation of the coil.

Meanwhile, in the structure of the stopper 1, the fixed wall 120 and the bent surface 121 are formed by reinforcing the metal magnetic coupling force, which is a design variable, and the metal magnetic coupling force and the coil magnetic flux density distribution are removed if appropriate. Alternatively, the basic structure may be square.

The stopper 1 shown in (e) is formed by separating the two bodies 122 and 123 having a space 124 at the center, and if the permanent magnet is applied to the moving body, the soldered portion of the coil is substituted for the F-PCB. It can be used for contacting the electrical output terminals of the and full bridge circuits, and the structure without F-PCB is also applicable.

And the stopper 1 comprised in this way is attached to the injection molding space shown in FIG. 3, The stopper 1 of FIG. 2 (a) (b) is a simple square injection molding mounting as shown to (a) of FIG. The stopper 1 of (c) is inserted into the space 140, and the stopper 1 of (c) is inserted into the injection molding mounting space 141 in which the guide protrusion 144 on which the bent surface 121 is engaged is formed (d). As shown in (c), the stopper 1 is fitted into the injection molding mounting space 147 in which the engaging groove 147 is formed, and (e) is the injection molding mounting space (d) of (d). 142).

In addition, in the injection molding mounting spaces 142 and 143 represented by (c) and (d), a locking step 146 to which the core 2 fitted to the coil 3 is fixed is further formed. Unexplained reference numeral 145 in the figure is a guide for supporting the gap 124 generated by dividing.

On the other hand, the core 2 is a ferromagnetic material and is inserted in the center of the coil 3, and as shown in FIG. 4, when a constant current flows through the coil 3, the magnetic flux for each length based on the long axis of the coil 3 is shown. When only the coil 3 is used in the density distribution chart, the magnetic flux density distribution curve represented by A is flattened in the longitudinal direction of the long axis of the coil 3 as shown in B, and serves as a stopper. The stopper 1 is a ferromagnetic material and is flattened more than when only the core 2 was used in the long axis direction of the coil as indicated by the magnetic flux density distribution curve C. FIG. The core 2 acting as described above may be formed in a quadrangle as shown in FIG. 5 (a), or as shown in (b), protrusions 112 may be formed at both ends of the body 111 to form a coil boundary surface 25. ), Consider the relationship between the magnetic flux density distribution of the coil and the magnetic coupling force of the metal.

In the above-described configuration, the coil 3 is made of an elliptical shape having one long axis when viewed from the coil boundary surface 25, which is a surface in contact with the permanent magnet 4 as an enamel wire, and is output from the control source 31. According to (11) and (13), it is a key component to determine the moving direction, position, and speed.

The magnetic flux density distribution curve generated in the coil 3 when a constant current is applied to the coil 3 is preferably such that the magnetic flux density is flat as a whole (hereinafter, having a constant characteristic). If the magnetic pole of the coil and the magnetic pole of the permanent magnet are different magnetic poles, the attraction force is generated, and if the same is the same, repulsive force is generated. Since it is composed of the force to move toward higher density by the density difference (hereinafter, magnetic flux density moving force), if it is not flat, the above-mentioned attraction force is strong only at the central portion of the coil 3 within the moving section, and the magnetic flux density moving force is weak. Since the coil has a nonlinear characteristic in the moving section, there is a problem in that the moving length of the linear control can be shortened. In this way, the core 2 and the stopper 1 serve to make the distribution of the coil magnetic flux density constant, and also to the permanent magnet 4 and the magnetic material even if the current flow applied to the coil 3 is blocked. The shaped core 2 and the stopper 1 make it possible to fix the position of the moving body in a position blocked by the metal magnetic coupling force.

On the other hand, as described above, the coil 3, the core 2, the stopper 1 constitutes the coil structure, and the moving body having a moving force, a moving distance, a linear control section and the weight by the magnetic flux density distribution curve are moved. If the relationship between the physical force (inertia, gravity, friction and combined forces) basically possessed in the stop motion is properly used in the design of the actuator, one component of the core (2) or the stopper (1) is removed and the configuration of the coil structure is removed. It is possible. In addition, when the coil assembly is pre-assembled and composed of an insert injection molding, it becomes a single part, thereby improving productivity in manufacturing an actuator.

The permanent magnets 4 are formed in a rectangular shape (rectangular or square) with a thickness as shown in Figs. 1, 6A to 6C, and as shown in Figs. 1 and 6A, the two vertices of one quadrangle are divided diagonally. By symmetrically magnetizing the N and S poles on the boundary, the magnetic flux density distribution of each magnetic pole is increased or decreased linearly (first function) like the diagonal slope.

The moving distance of the moving object depends on the length of the permanent magnet, and the strength of the magnetic flux density moving force varies according to the diagonal slope.

The bracket 21 is shaped as a ferromagnetic material (iron or silicon steel), and is formed in a rectangular shape as shown in FIG. 1 or as shown in FIG. 7A so as to be attached to both sides of the permanent magnet. 1) 21-2 is divided into two parts, or as shown in FIG. 7B, the protrusions 45 and 46 are formed at the ends of the bracket 21 so as to be bent, so that the one protrusion 45 is the other protrusion toward the permanent magnet. 46 is bent toward the hole of the injection molding to be mounted on the permanent magnet structure to prevent the release of the bracket from the injection by the projections 46 during assembly, and in the state that the bracket is fixed by the projections 45 of the permanent magnet There should be no departure.

The first role of the bracket thus formed prevents the magnetic flux of the permanent magnet from facing the opposite side of the bracket 21, and the second role is a linear (primary primary) magnetic flux density distribution curve of the permanent magnet as shown in FIG. And the third role increases the intensity of the magnetic flux by using the bracket 21 rather than before using the bracket 21 at the interface with the coil, and the increased intensity of the magnetic flux By increasing the magnetic coupling force to increase the magnetic flux density, if the magnetic flux density is the same, the current flowing through the coil can be lowered.

On the other hand, as described above, the magnetic flux density distribution curve of the permanent magnet as shown in FIG. 8A is ideally the form in which the magnetic flux density distribution curve increases and decreases linearly (first function) within the entire section. Even when magnetizing the N pole and the S pole symmetrically with respect to the diagonal connecting the two vertices of the rectangle like the magnet 4, the actual magnetic flux density distribution is shown at the both ends of the permanent magnet 4 as shown in FIG. 8B. S poles are present at the same time, the magnetic flux density is reduced to generate a non-linear section (hereinafter referred to as a dead zone, 27), a method for bringing the width of the dead zone 27 closer to Figure 8a will be described in more detail below. .

First, as shown in (a) of FIG. 6a, a permanent magnet having a rectangular pillar shape having a thickness is separated into two permanent magnets having a triangular prism shape having a thickness, and spaced apart by a predetermined distance or as shown in (b). Position the permanent magnet in the form of a triangular prism so that the center position is shifted from the diagonal, and change the position so that both end positions are located in a position other than the same line. When spaced in this way, if spaced apart, the magnetic flux density distribution curve is moved to the spaced position as indicated by the dotted line of FIG. 8B, so that the moving distance becomes longer and the linear section 26 is extended so that the two dead. It is possible to solve the problem of reducing the linear section 26 caused by the zone, but when the separation distance becomes longer than the dead zone, the linear section The overlapping distance becomes shorter, and the moving distance becomes shorter.

Meanwhile, an empty space or a nonmagnetic material is inserted between the two permanent magnets, and the permanent magnet structure is formed by mounting two permanent magnets, a bracket, and a nonmagnetic material in the form of a nonmagnetic material by combining with a bracket or an empty space. The two permanent magnets are moved by the distance of the triangle against each other and combined with the bracket to form the permanent magnet construct.

Second, it can be extended to change the shape of the magnet by changing the slope as shown in Fig. 6b, and third, as shown in Fig. 6c, the N, S poles are separated by parallel lines instead of diagonal lines, and the N, S poles are moved in the thickness direction of the permanent magnet 4. You can magnetize diagonally.

Third, the linear section can be extended by using the bracket 21.

The easiest and most practical method of the above methods is to apply the first and third methods.

The bracket 21 and the permanent magnet (4) constitutes a permanent magnet structure.

In the figure, reference numeral 14 denotes a terminal for connecting electrical wires to the coil.

Depending on the design variables (mechanical design range, such as the inductive flux density distribution and the magnetic coupling force between the core and the permanent magnet), a coreless design is possible.

9 shows the shape of the injection molding mounting space (hereinafter referred to as permanent magnet mounting space, 130,131) to be mounted on the permanent magnet structure.

The permanent magnet mounting space 130 shown in (a) is a hole to be applied when the contact area of the permanent magnet and the bracket is the same, and is the basic type of the permanent magnet mounting space, and the permanent magnet mounting space 131 shown in (b) is the cross-sectional area of the bracket. As a modification of the basic type to be applied when larger than this permanent magnet, 132 is a groove into which the bracket is inserted, and 133 is a fixing groove for fixing the protrusion 46 formed in the bracket.

One of the permanent magnet structure and the coil structure configured as described above is mounted as the core structure of the moving body and the other as the core structure of the fixed body to configure the actuator, and the weight of the moving body and the use of the F-PCB in the actuator design In consideration of comprehensive matters such as whether to install a coil or permanent magnet as a core component of the moving body.

On the other hand, when there are two or more moving bodies instead of one, the permanent magnet structure is coupled to the fixture injection molding, and the coil components are only possible to be coupled to each moving body injection molding. This is because it is difficult to control the moving bodies independently because of the magnetic coupling force between the permanent magnets, which are always active, if the permanent magnets are mounted on the moving bodies.

In the following embodiments of the present invention, as described above, it is assumed that the coil structure is the core structure of the movable body and the permanent magnet structure is the core structure of the fixed body.

One side of the permanent magnet and one side of the coil are disposed to face each other, and the surface facing the permanent magnet and the coil is hereinafter referred to as the coil interface 25. One side length of the permanent magnet (hereinafter referred to as the moving section, 24) is the theoretical maximum length that the moving body can move. The long axis and the moving section of the coil are perpendicular to each other.

As shown in FIG. 1, the driving circuit receives an operation control signal from the control source 31 and outputs an operation driving signal to the coil. The constant voltage source 6, the full bridge circuit 5 and the inverter circuit ( 7) including.

In the above configuration, the control source 31 is an image sense, micro process. It is composed of a focus sense, an input / output signal processor, a memory, etc., and may be composed of a single chip or a separate chip, and outputs control signals 13 and 11 related to the movement of the actuator, which is represented by 13 of the control signals. The control signal controls the moving or stopping of the moving object, the position fixing and the moving speed, and the control signal 11 controls the moving direction of the moving object, that is, the forward / reverse direction.

The constant voltage source (regulator) 6 receives an input voltage 8 from a battery or other voltage supply source, and supplies or cuts the output voltage 12 of constant magnitude to the full bridge circuit 5, and Supply and interruption are determined by the control signal 13 input from the control source 31. Although it depends on the circuit design method, it is assumed for the purpose of the present invention that the output voltage is ON when the control signal 13 is high and the output voltage is OFF when the control signal 13 is High.

The inverter circuit 7 changes the polarity of the control signal 11 input from the control source 31 and outputs the output signal 10. Output signal 10 (b, c) inverted in polarity with control signal 11 (a, d) is a pair of switch pairs s / w1 and s / w4 of the full bridge circuit 5, and s / w2 and s / w3 are A pair of full bridge circuit switches can be toggled to open / close by the control signal 11. This is to use the same type when embedding the full bridge circuit 5 in one IC.

If you design a separate circuit and apply each pair in different type (BJT if NPN and PNP, FET if N channel and P channel), you can control the full bridge circuit from the control source without using the inverter circuit.

The full bridge circuit 5 changes the direction of the current supplied to the coil 3 by the control signal 11 and serves to directly control the moving direction of the moving body in the present invention. The full bridge circuit 5 receives the signal 10 output from the inverter circuit 7 or the control signal 11 output from the control source 31 as described above, and the open / close BJT is electrically controlled. The switch may be configured by FETs, and diodes may be added to each switch of the full bridge circuit 5 so as to quickly remove the charging energy remaining in the coil.

The circuit design method is different depending on the type of the switch. However, for the purpose of explanation, the direction of the current flowing through the coil is 15 when the control signal 11 output from the control source 31 is high. It is assumed that the direction is 16, and it depends on the direction of winding the coil.However, for the purpose of the present invention, if the direction of the current applied to the coil is 15, the N pole magnetic pole is formed at the coil interface facing the coil and the permanent magnet. It is assumed that an induction pole of the S pole is formed at the rear coil interface.

So far, the role of assumptions and key components for the description of the linear motor according to the present invention, the role of circuit blocks and control signals, and the basic arrangement between the permanent magnet structure and the coil structure have been described. Based on the above description, the actual operations of the actuator, which is the actuator of FIG. 1 and the permanent magnet structure, that is, movement, stop, direction change, movement distance, and position fixing will be described.

When the control source 31 outputs the control signal 13 high, the output voltage 12 of the constant voltage source 6 is turned on, so that a current is supplied to the coil so that the coil interface 25 is polarized. In this state, when the control signal 11 is outputted high from the control source 31, an N pole is formed at the coil interface 25, and a force is generated to couple with the S pole of the permanent magnet 4, and the permanent magnet 4 Since the magnetic flux density of the S pole varies by distance, the force to be combined is moved to the place where the magnetic flux density of the S pole is highest (hereinafter, referred to as the forward direction 22 or the forward direction), and the coil structure is a permanent magnet (4). When the control source 31 outputs the control signal 13 high and the control signal 11 low when it is located at the highest distribution point or any point of the S pole magnetic flux density of the S pole, an S pole is formed at the coil interface 25. The coil structure is moved to the place where the N pole magnetic flux density of the permanent magnet 4 is the highest (hereinafter, the reverse direction 23).

In the stop operation, when the output of the control signal 13 is lowered from the control source 31, the flow of current is stopped in the coil, and the stop is stopped. ), To stop by the magnetic coupling force of the stopper (1). The state of maintaining the stop at any position in the moving section is called position fixing operation.

The control signals 11 and 13 outputted from the control source 31 are as shown in FIG. 10, and the change in the unit moving distance is represented by the high time of the control signal 13, that is, the pulse width as shown in FIG. It is possible by changing as described above. In addition, the high section of the pulse is a unit movement command for the moving object, and the low section is the processing section of the control source at the position after the moving body moves. Through the processing section, the controller receives the intensity of the focus value at that point, compares or calculates the setting value, stores various data related to the focus, and outputs the next unit movement control signal.

11 to 15c illustrate the shapes and arrangements of the component mounting spaces at the interface between the fixed body and the moving object, the mounting space of the component and the component, which are the core components and combinations of parts, in relation to the manufacture of the actual actuator according to the embodiment of the present invention.

Fig. 11 shows the arrangement of the constructs and the shape of the construct mounting space in accordance with the invention.

(A) to (d) of FIG. 11 are airs in which the permanent magnet structure mounting spaces 130 and 131 and the coil structure mounting spaces 140, 141, 142 and 143, and the fixed body including the permanent magnet body and the moving body including the coil body are spatially separated. A gap (Air Gap) 190 is illustrated, and the guide protrusion 159 and the guide groove 159a corresponding thereto are formed in the fixed body and the movable body, respectively, as shown in FIG. The guide groove 159a acts as a moving reference line of the movable body that moves the inside of the fixed body in parallel with the optical axis, thereby reducing the frictional force by reducing the contact area between the movable body and the fixed body, and preventing the twisting of the movable body between the fixed bodies. It is responsible for providing the coordinates of the award.

In addition, the air gap width between the guide protrusion 159 and the guide groove 159a is smaller than or equal to the width of the air gap 190 in another section.

In the structure where the coil structure is mounted on the moving body, it is possible to extend the solder terminal of the coil which is not wound on the coil to solder directly with the extension terminal of the full bridge output, and to apply the spring effect by the extension line of the coil. Flexible printed circuit board (F-PCB) is used as a stable structure. The F-PCB is electrically connected (soldered) to the coil terminal 14 and the shape of the F-PCB is shaped like a leaf spring to continuously supply current to the coil when the moving body moves. The F-PCB extension line mounting hole 158, which is a hole for shaping the F-PCB and supplying the F-PCB length extension line (to secure the space of the coil terminal soldering portion and providing a stable attachment surface to the moving body), is formed in the movable body. In the drawings, reference numerals 180, 181, and 182 denote partition walls between respective mounting holes.

In FIG. 11, the mounting holes shown in (a) to (c) are an example in which the coil member is mounted on the movable body and the F-PCB is applied. The mounting hole shown in (d) is on the contrary, the permanent magnet assembly is mounted on the movable body. The stationary body has a structure in which the coil structure is mounted and the coil is fixed in position so that the F-PCB is not required.

The reference line 184 is located at the position where the weight of the 191 direction and the weight of the 192 direction are balanced.

FIG. 13 is an exploded perspective view of a linear motor for controlling a focal length of a lens to which only one movable body on which a coil structure is mounted according to an exemplary embodiment of the present invention is applied.

The linear motor according to an embodiment of the present invention has a basic configuration of an upper case 330 for fixing the upper part of the fixture injection molding 337 and a lower case 340 for fixing the lower part of the fixture injection molding 337 and a movable body and a fixture. do. The movable body is basically composed of a movable body injection body 335 including a coil body, a lens body and a mounting space of the coil body, and the fixed body is basically composed of a stationary body injection body 337 including a mounting space of the permanent magnet body and the permanent magnet body. .

The upper case 330 is formed of a stainless or plastic injection molding, and the fixing hole 341 of the upper case 330 is connected to the fixing protrusion 359 of the fixture injection molding 337 so that the upper case 330 is fixed to the fixture. To be fixed. The light source hole 342 directed to the lens may have the same optical axis and different diameters as the lens 349.

The lens assembly 334 has a lens 349 embedded therein and a male thread line 343 is machined on the outer side thereof and is coupled to a female screw 351 formed in the body of the moving object injection molding 335 to fix the lens structure 343 to the moving object injection molding. do.

The movable body injection molding 335 is configured to mount or assemble the lens assembly 334 and the coil assembly, respectively, and the lens assembly 334 and the movable body injection molding 335 may be integrated by insert injection.

The F-PCB 336 selects an F-PCB having a very small modulus of elasticity. The F-PCB 336 has a connection end 345 which can be electrically connected to an extension line of the full bridge circuit output end, and a separation line 348 allowing the leaf spring operation. Moving part 392 to give a leaf spring effect to the hole 347 to prevent tearing by a number of repetitive movements, and a soldering end mounted in the F-PCB mounting hole and solderable for electrical connection with the coil end ( 346 and a length extension portion 331 which is treated with a double-sided adhesive or bond so as to be fixed to the movable body.

The stationary injection molded product 337 has a shape that is symmetrical with the shape of the mobile injection molded product 335 and has an air gap in dimensions, so that the moving object injection space having a shape larger than the shape of the mobile injection molded product 335 by air gap ( 356 and the upper case 330 and the lower case 340, the fixing protrusion (359) and the permanent magnet structure mounting hole 131 and the permanent magnet structure and the moving object injection (335) to separate the role of the coil interface The partition wall 180 is formed, and the outer shape may be a rectangular pillar shape or any shape may be applied.

The lower case 340 is made of a plastic injection molding, and the central axis is the same as the optical axis so that the image of the subject through the lens 360 and the hole 360 coupled to the protrusion (not shown) formed in the fixed injection molding 337 touch the sense or film. And the hole 361 which can be shaped into an arbitrary shape is shaped.

On the other hand, if a certain shape material (for example, F-PCB) is placed between the fixture injection molding 337 and the lower case 340, the lower side of the fixture injection molding is engraved according to the shape.

FIG. 14 is an exploded perspective view of a linear motor for controlling a focal length of a lens without an F-PCB applying only one movable body on which a permanent magnet structure is mounted according to an embodiment of the present invention. Permanent magnet assemblies 4 and 21 are mounted to form the mounting space 132 in which the component mounting holes 131 and the brackets 21 are installed, and the coil components 374, 375, 3, and 2 are mounted on the stationary injection molded product 373. And the space 142 in which the coil structure is mounted is different from that in FIG. 13, and the stoppers 373 and 375 constituting the coil structure are separately formed and bent parts 389 formed in the stoppers 373 and 375. Is formed to solder the electrical connection terminal of the output extension line of the full bridge circuit and the terminal of the coil. On the other hand, if the upper case is stainless steel, since each stopper is electrically polarized, it is necessary to insulate to prevent electrical shorts caused by the stainless steel.

15A to 15C are provided with two or more moving bodies equipped with a coil structure according to an embodiment of the present invention, and are applied to an optical apparatus for focusing by moving two or more lenses, and each lens to be moved is applied to each moving object. In order to electrically connect the coil to the moving body, the F-PCB 407 has an electric line connected to the coil, so that the moving body is configured in three steps in FIG. 1A, so that the first stage is six, the second stage is four, and the third stage is Two are formed because the coils mounted on the respective moving bodies have two soldering terminals, so that if the stage of each moving body is moved one step, the two are reduced. In the F-PCB, the moving part 392 and the length extension part 346 having the leaf spring effect are formed to have the same number of moving objects.

The F-PCB 407 thus formed arranges one F-PCB in a zigzag form as shown in Fig. 15B.

As an example of the modification of the F-PCB, FIG. 15C is a first stage 409 because the first stage does not move when the moving stage first stage moves so that a part irrelevant to the component for controlling the focal length is not moved, and thus a plate spring effect is not necessary. Does not form a moving part.

Meanwhile, a plurality of permanent magnet structures may be installed in the permanent magnet mounting space formed on the fixed body, and each permanent magnet member may be disposed in one-to-one with one of the plurality of movable bodies, or one permanent magnet member may be provided with a plurality of movable bodies. It can also be deployed one-to-many.

On the other hand, control signals 11 and 13 from the control source are required as many as the number of moving bodies, and drive circuits are also required as many as the number of moving bodies. The reason is that the operation driving signals must be applied to the coils mounted on the moving bodies so as to enable independent movement of each moving object from the control source.

On the other hand, in the above configuration, the upper case, the lower case, the moving body injection molding, the plastic resin of the body which is a fixed injection molding, it is preferable to use a resin having good lubricity, heat resistance, wear resistance, insulation, corrosion resistance, as an embodiment of the present invention Apply resin of POM series.

The upper case, the protrusions of the lower case and the hole and the coupling method other than the fixing, it is also possible to fasten using a screw having a screw thread and can also be attached by adhesive. In addition, as a method for fixing each component, for example, permanent magnets, coils, permanent magnet components, and coil components, the first insert injection or the bracket and stopper serving as the second case can be bent. Or fix it with a third adhesive (double sided tape or bonds).

It is also possible to fabricate the core and coil integrally in the coil arrangement, and the stopper may be deleted when the core is sufficient to serve as a stopper. Omission of the stopper results in a change in shape or dimensions of the space in which the coil arrangement is mounted.

On the other hand, in the above-mentioned linear motor, the upper case and the lower case are composed of parts or components in addition to the moving object injection molding, the IR filter, and the separate injection molding, etc., in addition to the moving injection molding in the moving injection molding mounting space shaped to the fixed injection molding. Alternatively, it can be mounted in combination with a fixture.

The forces associated with the movement of the moving body are basically related to the physical individual forces (inertia, gravity, friction, etc.) and the usage environment (moving the moving object vertically, moving the moving object vertically and downward, and moving the moving object in parallel with the ground). Based on the combined force of individual forces, the strength of the magnetic coupling force of the metal is optimally shaped by the structure of the magnetic flux strength of the permanent magnet and the structure of the stopper, core, bracket, and separation distance between the permanent magnet structure and the coil structure. In addition, the magnetic flux density movement force must be found for the movement of the moving object larger than the combined force of individual or combined force and metal magnetic coupling force. (For reference, the maximum magnetic flux density difference movement force is necessary when moving the moving object vertically in the moving environment.) Do.)

In addition, designing the actuator mechanically by minimizing the weight of the moving body, which is a key factor of the physical individual force of the moving object, which is the basis of the fundamental force in the design related to the moving of the moving object, is the first priority of the design. In addition, a design that minimizes the friction coefficient between the stationary body and the moving body is necessary.

First, the mechanical design is completed, and then the auto focus (AF) is adjusted by the electrical control method. The first step is the component of the electrical control signal 13 (the frequency and duty ratio of the PWM signal) that can be moved in any environment. Find one or more.

After finding the components of the electrical control signal 13, the focal length is automatically adjusted by applying a control algorithm for AF as follows. There are three major control algorithms. The first is the scan method, the second is the set value comparison method, and the third is the compromise between the set value comparison method and the scan method.

In the scanning method which performs AF from the electrical control signal 13 of one component, the moving object is moved to the initial position state through the direction control signal 11 of the moving object and the signal 13 for controlling the unit moving distance. The number of pulses of the control signal 13 for moving to the initial position state is the number of pulses for the movement from the initial position to the final position and the gamma. The reason is that the position of the moving object is not located in the moving section, and the additional reason is that the current must be applied to the coil to move to the initial position state. It also has the advantage of reducing the state. After the movement to the initial position, the state of the control signal 11 (the opposite direction) is changed and the control signal 13 is scanned and moved to the end point of the movement section, and the maximum value of the focal length sense unit and the number of pulses of the control signal 13 at that position are stored. After scanning the whole moving section, it moves closer to the position where the highest intensity sense value is stored, and focuses at an arbitrary point where the largest value is output from the focal length sensor.

The set value comparison method compares an output value of a focus sense based on an arbitrary initial focus value stored in a memory. The operation first moves a moving object to the initial position state and then moves a unit according to one pulse of the control signal 13. The output value from the focus sense is compared with any initial focus value stored in the memory to focus at that point when the output value is greater than or equal to the initial focus value. When the output value is smaller than the initial set focus value, the unit movement and the comparison between the two values are repeated, and the maximum output value of the focus sense and the number of pulses of the control signal 13 of the value are stored in another area of the memory and proceed to the limit point of the movement section. . If the output value of the focus sense was smaller than the initial set focus value in the whole moving section, the largest output value from the focus sense among all the moving sections is set as the reset focus value (hereinafter referred to as the reset value ((largest output value> = reset value)) and controlled. Change the direction of movement with the signal 11, move the unit with the control signal 11, and focus again by repeating the reset value and the output value of the focus sense as above.

The scanning method of performing AF with two components of electric control signals (signals having the same frequency and having a different duty ratio) 13 is first a control signal 13 having a large duty value and a control signal 11 for determining the initial direction of the lens. Move the moving object to the initial position. The number of pulses of the control signal 13 for moving to the initial position state is the number of large pulses for moving from the initial position to the final position and alpha. The reason is that the position of the moving object is not located in the moving section, and in order to move to the initial position state, since the current must be applied to the coil, the magnetization of the stopper and the core can be reduced by the heat generated in the coil due to the permanent magnet. There are also advantages. After moving the moving object to the initial position, change the state of the control signal 11 (move in the opposite direction), and move the scan signal to the end point of the moving section with the control signal 13 having a large pulse width. Remember the number of pulses. After scanning the entire moving section, move to the control signal 11 and control signal 13 with a large pulse width to the position closest to the position where the maximum output value of the focus sense of the highest intensity is stored, and then the control signal 13 with small pulse width. The micro-movement is performed with the direction control signal 11 to focus at an arbitrary point where the largest value is output from the focal length sensor.

In the scanning method of AF with three components of electric control signals (signals having the same frequency and having different duty ratios), first, the control signal 13 having the largest duty value and the control signal for determining the initial direction of the lens The moving object is moved to the initial position with 11. The number of pulses for moving to the initial position state is the number of largest pulses + gamma (slack) for moving from the initial position to the final position. The reason is as mentioned in the two electrical control signals. After moving the moving object to the initial position, change the state of the control signal 11 (move in the opposite direction), scan the control signal 13 with the second largest pulse width to the end point of the moving section, and set the maximum value of the focal length sensor and its The number of pulses of the control signal 13 at the position is stored. After scanning the entire moving section, move to the control signal 13 and control signal 11 with the second largest pulse width to the point closest to the point where the highest sensed value is stored, and then control with the smallest pulse width. A small shift is made to the signal 13 and the direction control signal 11 to focus at an arbitrary point where the largest value is output from the focal length sensor.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic configuration of a linear motor for lens focal length control according to the present invention.

2 is a view showing the structure of a stopper according to the present invention.

3 is a view showing the injection molding space is installed permanent magnet structure.

4 is a diagram showing a magnetic flux density distribution according to the configuration of a coil structure.

5 shows the shape of a core;

6a to 6c is a view showing the shape and configuration of the permanent magnet.

7A to 7B are views showing the shape and configuration of the bracket.

8A and 8B are graphs showing a magnetic flux density distribution curve according to a permanent magnet.

9 is a view showing an injection mounting space in which the permanent magnet construct is to be mounted.

10 is a diagram showing a moving object direction control signal and a moving control signal (for example, a PWM control signal of two components) outputted from a control source;

11 is a view showing the density of one side arrangement structure of the assembly mounting space and the structure mounting space in accordance with the present invention.

12 is a diagram showing a reference line of moving body movement.

FIG. 13 is an exploded perspective view of a linear motor for controlling a focal length of a lens to which only one movable body on which a coil structure is mounted according to an embodiment of the present invention is applied; FIG.

FIG. 14 is an exploded perspective view of a linear motor for controlling a focal length of a lens without an F-PCB to which only one movable body equipped with a permanent magnet structure according to an exemplary embodiment of the present invention is applied; FIG.

15A to 15C are views showing two or more moving bodies equipped with a coil structure according to an exemplary embodiment of the present invention.

Claims (23)

A control source 31 for outputting control signals 13 and 11 related to the movement of the moving body, a driving circuit for receiving the operation control signal from the control source and outputting an operation driving signal, and a coil constituting the moving body or the fixed body (3); A permanent magnet structure including a coil structure and a permanent magnet (4), and a moving object and a stationary injection body to which the coil structure and the permanent magnet structure are combined. In a linear motor for lens focal length control, in which a movable vehicle mounting space is constituted, The coil structure is composed of a coil (3) and a core (2) and a stopper (1) made of ferromagnetic material inserted into the center of the coil, and the permanent magnet structure is a bracket made of the permanent magnet (4) and ferromagnetic material (21) implements the modularization of the core component components, shape the permanent magnet structure mounting space and the coil structure mounting space in one space of the moving object injection and the fixed body injection molding, and mount the coil structure and the permanent magnet structure in the mounting space In the mounting direction, the coil and the permanent magnet are mounted to face each other based on the coil interface 25 so that when the movable body is installed in the movable body mounting space, which is shaped on the stationary injection molding, one side space density arrangement structure of the core parts is formed. Linear motor for lens focal length control, characterized in that. The method of claim 1, wherein the permanent magnet (4) is formed as a rectangle having a small thickness by dividing the two vertices on one side of the rectangle diagonally magnetized the N pole and the S pole symmetrically on the diagonal border of each pole distance A linear motor for controlling the focal length of a lens, wherein the magnetic flux density distribution is manufactured to increase or decrease linearly (first function) such as a diagonal slope. The method of claim 2, wherein two permanent magnets are manufactured in a triangular shape having a small thickness such that a permanent magnet magnetized based on a diagonal of a quadrangle is formed along a diagonal and spaced apart from each other by a predetermined distance, or centered on a diagonal line. Linear motor for controlling the focal length of the lens, characterized in that the position of both ends are differently installed by positioning the center position. 4. The lens focus of claim 3, wherein a nonmagnetic material is interposed between two permanent magnets having a triangular shape to form a permanent magnet structure with two permanent magnets, a bracket, and a non-magnetic material having a space shape. Linear motor for distance control. The linear motor for controlling the focal length of a lens according to claim 1, wherein the coil member is inserted and ejected to form a single component. The method of claim 1, wherein in the stationary injection molding or moving object injection, the coil component mounting space and the permanent magnet component mounting space are disposed to face each other with respect to the coil interface, and the permanent magnets coupled to the mounting space are parallel to each other in comparison with the optical axis. (170 to 190 angles) and the coil is a linear motor for controlling the focal length of the lens, characterized in that the coil's long axis close to each other (80 to 100 angles) compared to the optical axis. The linear motor for lens focal length control according to claim 1, wherein an air gap is formed between the movable body and the fixed body. The method of claim 1, wherein two moving reference lines 159 are formed on the moving object injection molding, and a position to be shaped on the moving object is made by placing two points in one space where the above-described core component components are concentrated. When connected by the line 184, the weight of the moving object is positioned between the equilibrium position and the coil boundary surface, and the moving reference line shape is based on the shape provided in the drawing, and can be changed according to the design specification. A linear motor for focal length control, characterized in that a shape corresponding to a position corresponding to the movement reference line of the movable body is formed in the movable body mounting space and separated by an air gap. The linear motor for controlling the focal length of the lens of claim 1, wherein the moving body injection molding and the fixed injection molding constitute a coil assembly mounting space and a permanent magnet assembly mounting space, and an outer periphery of the component mounting space of each injection molding forms a partition wall. . The inverter (7) according to claim 1, which receives two control signals output from the control source, changes the direction of the current flowing through the coil, and a constant voltage source (6) for interrupting or supplying the current flowing through the coil. A linear motor for controlling a focal length of a lens comprising a semiconductor chip comprising a driving circuit composed of a full bridge circuit (5). 2. The lens focal length control linear motor according to claim 1, wherein a circuit consisting of an inverter (7) and a full bridge circuit (5) for changing the direction of the current flowing through the coil is composed of one semiconductor chip. The linear motor for lens focal length control according to claim 1, wherein the control source (31), the inverter (7), the full bridge circuit (5), and the constant voltage source (6) are composed of one semiconductor chip. The linear motor of claim 1, wherein the stationary body is coupled to the permanent magnet assembly and the movable body is coupled to the coil assembly and installed in the movable body mounting space of the stationary injection molding. The method according to claim 13, wherein when the coil structure is coupled to the moving body, a flexible printed circuit board (hereinafter referred to as F-PCB) is provided to continuously supply current to the coil even when the moving body moves. The plate spring-shaped part cut into grooves, the terminal of the coil, the soldering part for soldering, the F-PCB length extension part for fixing to the F-PCB mounting space shaped on the movable body, and the electric extension terminal of the full bridge circuit, Linear motor for controlling the focal length of the lens, characterized in that the terminal portion for the electrical connection. The linear motor of claim 1, wherein the fixed body is coupled to the coil component and the movable body is coupled to the permanent magnet component and installed in the movable body mounting space of the fixed body injection product. 16. The stationary body of claim 15, wherein the fixture is coupled to the coil assembly so that the two stoppers of the coil assembly are separated into two, and the two stoppers separated from the two coil terminals are soldered one-to-one and one-to-one connected to the two full bridge circuit output extension terminals. Linear motor for controlling the focal length of the lens, characterized in that. The linear motor for controlling a focal length of a lens according to claim 1, wherein at least one movable body in which one permanent magnet structure is coupled to the fixture injection molding and two or more moving bodies in which the coil assembly is coupled is installed in the moving object mounting space of the fixture injection molding. The lens focal point of claim 1, wherein two or more permanent magnet structures are coupled to one permanent magnet component mounting space of the fixture injection unit, and two or more movable bodies to which the coil assembly is coupled are installed in the moving object mounting space of the fixture injection body. Linear motor for distance control. 19. The method of claim 17 and 18, wherein when the moving body having the coil structure is installed in the moving body mounting space of two or more stationary injection molding, the moving body injection molding is provided with a mounting space so that the F-PCB can be arranged zigzag on each moving body. And forming two F-PCBs such that the F-PCB has an F-PCB length extending portion, a coil soldering portion, and a leaf spring shape portion as many as the number of moving bodies. The method according to claim 1, wherein a camera-related fixed part or component is applied to the movable body-mounted product mounting space shaped to the fixed body-shaped injection molding, and coupled to an upper case, a lower case, or a fixed body to be configured in the movable body-mounted mounting space. Linear motor for lens focal length control. It consists of an image sense, a micro process, a focus sense, an input / output signal processor, a memory, and the like, and receives an operation control signal from a control source 31 that outputs control signals 13 and 11 related to the movement of the moving object. A constant voltage source that outputs an operation drive signal and outputs an output voltage 12 of constant magnitude by receiving an input voltage 8 from a battery or other voltage supply source according to the control signal 13 input from the control source 31 A ferromagnetic core in the center of the coil 3 and a drive circuit composed of an inverter 7 and a full bridge circuit 5 for changing the direction of the current supplied to the coil 3 by the control signal 11 and 6 described above. (2) the permanent magnet structure formed by inserting a coil structure composed of a stopper (3) which is a ferromagnetic body, and a bracket (21) made of ferromagnetic material on the opposite side of the coil (3) of the permanent magnet (4); With one coil construct In the lens focal length control linear motor comprising a movable body and fixed body Extrusions Extrusions the old magnet structure body is installed,  In order to control the auto focus distance AF by outputting the control signal 13 having the same frequency and having three duty ratios, respectively, to control the auto focus distance AF, first, the moving object is returned to an initial position for focal length control. In order to move, the control signal 11 for controlling the moving direction of the moving object is set in the direction toward the initial position state, and the number and the margin for moving the control signal 13 having the largest duty ratio value from the initial position to the final position. Apply the number to move the moving object completely to the initial position, move the moving object to the initial position, change the state of the control signal 11 and move the scan to the end point of the moving section with the control signal 13 having the second largest duty ratio value. Find the point where the output value of the focus sense part, which is a part of the control source, is the largest, and store the number of control signals 13 at that point. After scanning the whole moving section, change the state of control signal 11 and move to the point closest to the point where the largest output value stored as control signal 13 with the second largest duty ratio value occurs, and then the smallest duty ratio. A focal length control method comprising moving to a small distance with a control signal 13 having a value and focusing at an arbitrary point where the largest output value is generated from the focus sensing unit. It consists of an image sense, a micro process, a focus sense, an input / output signal processor, a memory, and the like, and receives an operation control signal from a control source 31 that outputs control signals 13 and 11 related to the movement of the moving object. A constant voltage source that outputs an operation drive signal and outputs an output voltage 12 of constant magnitude by receiving an input voltage 8 from a battery or other voltage supply source according to the control signal 13 input from the control source 31 A ferromagnetic core in the center of the coil 3 and a drive circuit composed of an inverter 7 and a full bridge circuit 5 for changing the direction of the current supplied to the coil 3 by the control signal 11 and 6 described above. (2) the permanent magnet structure formed by inserting a coil structure composed of a stopper (3) which is a ferromagnetic body, and a bracket (21) made of ferromagnetic material on the opposite side of the coil (3) of the permanent magnet (4); One coil construct and zero In the linear motor for controlling the focal length of the lens comprising a moving body injection molding and a fixed body injection molding on which a spherical magnet structure is installed, In order to control the auto focus distance AF with the electrical control signal of two components (the frequency is the same and the duty ratio is different) 13, the moving object is first moved to the initial position state for the focal length control. Set the state of the control signal 11 to control the direction of movement to the initial position state, and apply the control signal 13 having a large duty ratio value as the number and the number of spares for moving from the initial position to the final position Can be placed in the initial position completely, move the moving object to the initial position, change the state of control signal 11 and scan move to the end point of the moving section with control signal 13 having a large duty ratio value. Find the point with the largest output value in the sense unit, remember the number of control signals 13 at that point, and control after scanning the whole moving section. After changing the state of the signal 11 and moving to the point closest to the point where the largest output value stored as the control signal 13 having a large duty ratio value occurs, a small distance is moved to the control signal 13 having a small duty ratio value. A focus distance control method characterized by focusing at an arbitrary point where the largest output value from negative occurs. It consists of an image sense, a micro process, a focus sense, an input / output signal processor, a memory, and the like, and receives an operation control signal from a control source 31 that outputs control signals 13 and 11 related to the movement of the moving object. A constant voltage source that outputs an operation drive signal and outputs an output voltage 12 of constant magnitude by receiving an input voltage 8 from a battery or other voltage supply source according to the control signal 13 input from the control source 31 A ferromagnetic core in the center of the coil 3 and a drive circuit composed of an inverter 7 and a full bridge circuit 5 for changing the direction of the current supplied to the coil 3 by the control signal 11 and 6 described above. (2) the permanent magnet structure formed by inserting a coil structure composed of a stopper (3) which is a ferromagnetic body, and a bracket (21) made of ferromagnetic material on the opposite side of the coil (3) of the permanent magnet (4); One coil construct and zero In a linear motor for controlling the focal length of a lens including a moving object injection molded body and a fixed object injection body provided with a spherical magnet structure, a method of controlling the auto focus distance AF by an electrical control signal 13 of one component, focusing the moving object first To move to the initial position state for distance control, set the state of the control signal 11 that controls the moving direction of the moving body toward the initial position state, and the number and margin for moving the control signal 13 from the initial position to the final position. By applying the number of times, the moving object can be completely positioned at the initial position, and after moving the moving object to the initial position, the state of the control signal 11 is changed, and the control signal 13 scans and moves to the end point of the moving section. Find the point where the negative output value is the largest and set the output value in the Set the value equal to or less than the maximum output value.) After scanning the whole moving section, change the state of the control signal 11 and move the unit by the control signal 13, and move the stored setting value and each unit. A focal length control method characterized in that when the output value is smaller than the set value compared to the focus sense output value of the point, the unit moves to the next position and focuses at that point when it is equal to or larger.

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