KR100723252B1 - Apparatus for actuating a lens module - Google Patents

Abstract

An improved lens module driving apparatus for driving back and forth a lens module embedded in a camera module is provided.

The present invention, the lens barrel comprising at least one lens; An actuator having an output member at one end of the body to generate a driving force upon output of power and to output the driving force; A reciprocating member reciprocating in the optical axis direction by a driving force of the actuator, having a first connection portion connected to the output member of the actuator and a second connection portion connected to the lens barrel; And a plurality of guide pins assembled with the lens barrel to guide linear movement of the lens barrel, wherein the second connection portion has a distance from the plurality of guide pins to a main guide pin than a distance to an auxiliary guide pin. Provided is a short formed lens module driving device.

According to the present invention, it is possible to minimize the tilt phenomenon and the movement resistance caused by friction with the guide pin during the movement of the lens barrel, thereby greatly improving the durability of the parts, and obtaining the clear image quality through the camera module.

Lens Barrel, Actuator, Guide Pin, Camera Module, Lens Module Drive, Tilt

Description

Lens module drive unit {APPARATUS FOR ACTUATING A LENS MODULE}

1 is a perspective view showing a lens module driving apparatus using a stepping motor according to the prior art.

2 is an operation explanatory diagram showing a position detection unit employed in the lens module driving apparatus according to the prior art.

3 is a detailed view of a lens module driving apparatus according to the related art,

      a) is a perspective view of the appearance, b) a plan view.

4 is a graph showing the lens barrel position according to the number of applied signals (time) in the lens module driving apparatus according to the related art.

5 is an external perspective view of the lens module driving apparatus according to the present invention;

6 is a plan view showing a lens module driving apparatus according to the present invention.

7 is a view showing in detail the connection portion of the main guide pin and the lens barrel in the lens module driving apparatus according to the present invention,

      a) when the connecting length is 20mm,

      b) If the connection length is 40 mm.

8 is a graph showing the amount of tilt for the length of the various connecting portion of the main guide pin and the lens barrel in the lens module driving apparatus according to the present invention, respectively.

9 is a plan view showing a tolerance that the main guide pin and the auxiliary guide pin is coupled to the lens barrel in the lens module driving apparatus according to the present invention, respectively.

10 is a graph showing a tilt amount and cumulative frictional force with respect to a distance traveled by a lens barrel using various size tolerances in which a main guide pin and an auxiliary guide pin are coupled to a lens barrel in the lens module driving apparatus according to the present invention. ,

      a) degree of tilt over distance, b) cumulative friction over distance.

11 is a graph showing the lens barrel position according to the number of applied signals (time) in the lens module driving apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

1 .... lens module driving apparatus according to the present invention 10 .... lens barrel

20 .... Actuator 25 .... Output member

30 .... Reciprocating members 32a, 32b .... First and second connections

40a, 40b .... multiple guide pins 42 .... opening

200 .... Conventional Lens Module Drive 210 .... Lens Group for Zoom

220 .... Focus lens group 215,225 .... Stepping motor

213,223 .... Light sensor 305 ... Drive motor

307 .... Lead Screw 310 .... Screw Lever

315 .... Zoom lens barrel 317a, 317b .... Guide pin

322 .... Opening District d1, d2 ... Street

k1, k2 .... Tolerance l .... Length

The present invention relates to a device for driving the lens module built in the camera module back and forth, and more particularly, to minimize the tilt of the lens barrel and the moving friction force to achieve a smooth movement on the guide pin to prevent damage to the device In addition, the present invention relates to an improved lens module driving apparatus for improving image quality of a camera module.

Generally, a camera phone is installed in a mobile phone, and a camera phone in which a camera function of taking a moving picture and a still picture of an object with a mobile phone and storing it and transmitting the same to a counterpart is merged.

These camera phones are not just a function of taking an object, but additional functions such as a focus function for adjusting the focus of an object to be photographed and a zoom function for making a far object closer or closer to a far object are added. It is true.

The zoom function is roughly divided into digital zoom and optical zoom. The digital zoom is a method of enlarging an image by the image sensor itself independently of the lens, and is implemented on the same principle as enlarging an image in a graphic program. Although there is an advantage that the object can be seen or enlarged closer, there is a disadvantage that the resolution is lower than the original image because the lens does not move.

 Accordingly, the camera phone has an optical zoom, which has a merit of photographing a distant object without deterioration of image quality in such a way as to enlarge a subject by reducing or increasing a focal length while moving multiple lenses directly as in a digital camera. It is also generally employed in the camera phone area.

On the other hand, the lens transport structure for transporting the lens in the optical zoom method is usually divided in several ways.

1) Lens transfer structure using stepping motor

The optical zoom used in the digital camera is applied to the camera phone as it is, and it has the advantage of strong power and high reliability by driving the gear by engaging the stepping motor, but it has the disadvantage of being bulky and expensive. have.

2) Lens conveyance structure using liquid hydraulic pressure

It has the advantage of precisely controlling the transfer by putting liquid material between the lens to be transferred and then expanding and contracting by applying pressure to the liquid material so that the lens moves, but it consumes a lot of power when pressurizing the liquid. There is this.

3) Transfer structure of lens using piezoelectric ultrasonic motor

The lens is transported by using a motor made of piezoelectric ceramic, which has the advantage of miniaturization of the product which is smaller in volume than the conventional stepping motor method, but the gear wears out quickly and shortens the service life. It is known to have disadvantages.

4) Structure to transfer lens by solenoid method using electromagnet

A magnet and a coil are placed around the barrel of the camera module, and a magnet is also placed around the lens in the barrel, and then the lens moves directly through a current. This is known to be excellent in volume and cost, but finely conveys the lens. It is known that there is a disadvantage in that adjustment is difficult.

1 is a perspective view showing a lens module driving apparatus using a conventional stepping motor, and FIG. 2 is a plan view showing a position detecting unit employed in a lens module driving apparatus using a conventional stepping motor. The driving device 200 uses stepping motors 215 and 225 as means for providing a driving force for transferring the zoom lens group 210 and the focusing lens group 220, respectively, and the stepping motor 215 When driving 225, the rotational driving force transmitted through the male screw parts 215a and 225a is converted into a linear reciprocating motion to transfer the zoom lens group 210 and the focus lens group 220 in the optical axis direction.

In addition, the position detection unit for detecting the transfer position of the zoom lens group 210 and the focus lens group 220 is each of the detection plate (212, 222) and integrally provided in the lens group (210, 220) and And optical sensors 213 and 223 for detecting the movement of the detection plates 212 and 222.

Accordingly, the detection plates 212 and 222 are disposed in the detection plate passage grooves 213a and 223b of the photosensors 213 and 223 which are fixed in position, and are provided in the photosensors 213 and 223. Since the light emitting part 202a and the light receiving part 202b are provided, respectively, when the detection plate 212 and 222 passes through the detection plate passage grooves 213a and 223a, The detection light emitted toward the light-receiving unit 202b is blocked by the detection plates 212 and 222 to detect the movement of the detection plates 212 and 222 to detect the movement of the lens groups 210 and 220. Position detection is performed, and zoom and focusing can be performed based on this.

However, the stepping motor 215, 225 has the advantage of high reliability and excellent position accuracy because it moves only a given step according to the control signal when the power is applied, but if the torque is not enough, the optical sensor ( 213 and 223 may cause an error that may not accurately detect the position of the lens group 210 and 220, and since the error information cannot be fed back, it is difficult to correct the detection error. have.

In addition, when implementing the structure to transfer the lens using the stepping motor 210, 220 as described above, the power consumption of the motor is larger than 500mW, which shortens the use time of the battery of the camera phone, the battery There was a problem in that the heat generated by the heat generated from the additional generation.

In order to solve such a conventional problem, a different method is described in FIGS. 3A and 3B, and a method of providing a driving force for transferring a zoom lens group and a focus lens group to a plurality of motors, respectively, has been proposed. . This prior art is as shown in Figure 3, the drive motor 305 is used, a screw lever 310 is connected to the lead screw 307 of the motor 305, respectively, to the screw lever 310 The lens barrel 315 including the zoom lens barrel or the focus lens barrel is connected and transported.

However, this conventional structure has a defect which is effective but not solved by using the plurality of motors 305.

That is, the lens barrel 315 is a portion connected to the screw lever 310 is close to the auxiliary guide pin 317b portion of the portion connected to the plurality of guide pins 317a and 317b, the main guide pin ( 317a). In addition, a portion connected to the auxiliary guide pin 317a has a structure in which an opening 322 is formed at the zoom lens barrel 315 side, and a portion connected to the main guide pin 317a is the zoom lens barrel 315. The cylindrical structure is formed on the side), and each guides it in the process of moving the zoom lens barrel 315. However, due to the conventional coupling structure, the zoom lens barrel 315 is tilted to one side during its movement. Or a large friction force with the guide pins 317a and 317b, resulting in an uneven movement problem such as irregular movement of the zoom lens barrel 315.

In addition, this problem is also related to the clearance tolerance (tolerence) that the auxiliary guide pin (317b) and the main guide pin (317a) is coupled to the zoom lens barrel 315, do not adequately secure the clearance tolerance of the appropriate size As a result, the zoom lens barrel 315 does not move to the correct position at the correct time, thereby degrading the performance of the camera and causing the durability.

4 shows a series of experimental results showing the transfer result of the zoom lens module 315 related thereto.

That is, as shown in FIG. 4, the number of applied signals required to reach the lens position indicated by the vertical axis in the graph is very large, and thus takes a long time.

The present invention is to solve the above conventional problems, the object is to achieve a smooth movement by minimizing the tilt (Tilt) phenomenon and movement resistance caused by friction with the guide pin during the movement of the lens barrel in the camera module The present invention provides an improved lens module driving apparatus to prevent damage to the device by greatly improving the durability of the lens barrel parts.

Another object of the present invention is to provide an improved lens module driving apparatus for improving an image quality obtained through a camera module by accurately positioning a lens barrel at a predetermined position at a predetermined time.

The present invention to achieve the above object,

A lens barrel including at least one lens;

An actuator having an output member at one end of the body to generate a driving force upon output of power and to output the driving force;

A reciprocating member reciprocating in the optical axis direction by a driving force of the actuator, having a first connection portion connected to the output member of the actuator and a second connection portion connected to the lens barrel; And

And a plurality of guide pins assembled with the lens barrel to guide the linear movement of the lens barrel.

The second connector provides a lens module driving apparatus, wherein a distance from the plurality of guide pins to a main guide pin is shorter than a distance to the auxiliary guide pin.

In addition, the present invention preferably provides a lens module driving apparatus characterized in that the length of the main guide pin is coupled to the lens barrel is at least 4.0mm.

In addition, the present invention preferably provides a lens module driving apparatus, characterized in that the tolerance that the main guide pin is coupled to the lens barrel is 5㎛, the tolerance that the auxiliary guide pin is coupled to the lens barrel is 20㎛.

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

The lens module driving apparatus 1 according to the present invention includes a lens barrel 10 including at least one lens, as shown in FIG. 5. The lens barrel 10 may be a conventional zoom lens barrel. In addition, the present invention includes an actuator 20 having an output member 25 at one end of the body portion to generate a driving force upon outputting power and output the driving force.

The actuator 20 is preferably a piezoelectric ultrasonic motor and the output member 25 is a lead screw with a thread.

In addition, the present invention includes a first connecting portion 32a connected to the output member 25 of the actuator 20 and a second connecting portion 32b connected to the lens barrel 10 of the actuator 20. Having a reciprocating member 30 reciprocated in the optical axis direction by the driving force, the reciprocating member 30 is composed of a screw lever for transmitting the driving force of the actuator 20 to the lens barrel 10, The first and second connecting portions 32a and 32b are connected to the output member 25 and the lens barrel 10 of the actuator 20, respectively.

Thus, the screw lever, which is the reciprocating member 30, is screwed to the lead screw, which is the output member 25 of the actuator 20.

In addition, the present invention includes a plurality of guide pins 40a and 40b assembled with the lens barrel 10 to guide the linear movement of the lens barrel 10, wherein the plurality of guide pins 40a and 40b ) Includes a main guide pin (40a) for coupling in a cylindrical structure, and an auxiliary guide pin (40b) for coupling to form an opening sphere (42) on one side.

In the present invention, the position of the second connecting portion 32b is closer to the main guide pin 40a among the plurality of guide pins 40a and 40b, and is located far from the auxiliary guide pin 40b. to be.

As shown in FIG. 6, the distance d1 between the second connecting portion 32b of the screw lever constituting the reciprocating member 30 and the main guide pin 40a is equal to the second connecting portion 32b and the auxiliary guide. It is formed closer to, or shorter than, the distance d2 between the fins 40b.

Therefore, the traction drive force of the actuator 20 transmitted from the first and second connecting portions 32a and 32b is primarily transmitted through the main guide pin 40a, and then to the auxiliary guide pin 40b, so that the lens The barrel 10 is moved.

Through this structure, the present invention allows the lens barrel 10 to be moved more stably on the plurality of guide pins 40a and 40b than in the related art.

In the present invention, the length l of the main guide pin 40a coupled to the lens barrel 10 is greater than at least 4.0 mm.

As shown in a) and b) of FIG. 7, when the length l between the main guide pin 40a and the lens barrel 10 is smaller than 4.0 mm, the plurality of guide pins 40a ( 40b) is inclined to one side during the movement of the lens barrel 10, causing a tilt phenomenon to form a large tilt and frictional resistance of the lens barrel 10.

Since the lens barrel 10 is connected to slide while surrounding the main guide pin 40a in a cylindrical shape, the length l in which the lens barrel 10 is coupled to the main guide pin 40a is thus the lens barrel 10. Influence on the tilting phenomenon to be inclined to one side during the movement of).

As described above, a series of experiments are performed to find the optimal length l that the main guide pin 40a and the lens barrel 10 are coupled to, and this is about the tilt amount with respect to the moving distance of the lens barrel 10. Was measured and plotted in FIG. 8.

In each experiment, the length l of the coupling between the main guide pin 40a and the lens barrel 10 was increased from 2.0 mm shown in Fig. 7A to 2.5 mm, 3.0 mm, 3.5 mm, and shown in Fig. 7B). 4.0 mm as described above, and then, these were measured and measured by the amount of tilt according to the moving distance.

As a result of this experiment, it was determined that the amount of tilt greatly decreased as it progressed from 2.0 mm to 4.0 mm as shown in FIG. 8. In other words, when the length l of the lens barrel 10 is coupled to the main guide pin 40a is at least 4.0 mm or more, it is possible to obtain an advantageously small amount of tilt.

In addition, in the present invention, the tolerance k1 at which the main guide pin 40a is coupled to the lens barrel 10 is 5 μm, and the tolerance k2 at which the auxiliary guide pin 40b is coupled to the lens barrel 10 is It consists of 20 micrometers.

That is, the lens barrel 10 is in contact with the guide pins 40a and 40b as shown in FIG. 9 in the process of being coupled to the main guide pin 40a and the auxiliary guide pin 40b. Tolerances k1 and k2 of cylindrical holes or openings affect the amount of tilt and frictional force of the lens barrel 10.

The influence of the tilt amount and the frictional force is determined by considering the tolerance k1 of the main guide pin 40a and the tolerance k2 of the auxiliary guide pin 40b at the same time.

To this end, a series of experiments are conducted to obtain the optimum tolerance k1 (k2) between the main guide pin 40a and the auxiliary guide pin 40b, and this is the amount of tilt for the moving distance of the lens barrel 10. And cumulative frictional force was measured and shown in the diagrams in Figs.

In each experiment, the tolerance k1 of the main guide pin 40a and the tolerance k2 of the auxiliary guide pin 40b were selected as shown in Table 1 below, and the results were shown by experiments.

TABLE 1

division Main guide pin Auxiliary guide pin Judgment Run 1 5 μm 5 μm Good tilting, moderate friction Run 2 10 μm 10 μm Bad tilting, bad friction Run 3 5 μm 20 ㎛ Good tilting, good friction Run 4 10 μm 20 ㎛ Bad tilting, bad friction Run 5 7.5㎛ 15 μm Bad tilting, bad friction

Therefore, according to the present invention, the tolerance k1 for coupling the main guide pin 40a to the lens barrel 10 is 5 μm, and the tolerance k2 for coupling the auxiliary guide pin 40b to the lens barrel 10. When the thickness was 20 µm, it was determined that it was the best in terms of the amount of tilt and the strength of the cumulative frictional force.

And the present invention, as shown in Fig. 11, a series of experiments were conducted to see if the lens barrel 10 can reach the desired position in a timely manner.

This was done in the same way as was done with the conventional structure with respect to FIG. 4, and the result was very good as shown in FIG.

That is, the number of applied signals (time) in which the lens barrel 10 reaches a desired position has been shortened by more than twice as compared with the prior art, which is a tilt phenomenon of the lens barrel 10 generated when the lens barrel 10 is moved compared with the conventional art. The frictional resistance is greatly reduced, which means that the lens barrel 10 is smoothly moved in accordance with a desired position and a desired time.

Accordingly, the present invention solves the conventional problem related to the movement of the lens barrel 10 in this manner.

As described above, according to the present invention, the movement of the lens barrel in the camera module minimizes the tilt phenomenon and movement resistance caused by friction with the guide pin, thereby minimizing parts wear related to the lens barrel movement. An effect which can greatly improve durability is obtained.

In another aspect, the present invention provides an effect of obtaining a clear image quality through a camera module by being able to quickly position to a predetermined position within a predetermined time with respect to the movement of the lens barrel.

In addition, the reliability of the operating characteristics can be secured in relation to the conveyance of the lens barrel, and accordingly, the effect of mass-producing a high-quality camera module is also obtained.

Claims (5)

A lens barrel including at least one lens; An actuator having an output member at one end of the body to generate a driving force upon output of power and to output the driving force; A reciprocating member reciprocating in the optical axis direction by a driving force of the actuator, having a first connection portion connected to the output member of the actuator and a second connection portion connected to the lens barrel; And And a plurality of guide pins assembled with the lens barrel to guide the linear movement of the lens barrel. The second connector is a lens module driving apparatus, characterized in that the distance from the plurality of guide pins to the main guide pin is formed shorter than the distance to the auxiliary guide pin. The lens module of claim 1, wherein the actuator is a piezoelectric ultrasonic motor, the output member is a lead screw with a thread, and the reciprocating member is screwed to the output member of the actuator. Drive system. The lens module driving apparatus of claim 1, wherein the lens barrel is coupled to the main guide pin in a cylindrical structure, and forms an open hole to couple to the auxiliary guide pin. The lens module driving apparatus of claim 1, wherein a length of the main guide pin coupled to the lens barrel is at least 4.0 mm. The lens module driving apparatus of claim 1, wherein a tolerance of coupling the main guide pin to the lens barrel is 5 μm, and a tolerance of the auxiliary guide pin to the lens barrel is 20 μm.

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