KR20070054303A - Control apparatus for focus of the camera and its manufacture method - Google Patents

Abstract

 BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a focus control apparatus capable of varying the focus of a camera lens, and a method of manufacturing the same, in particular for a camera.

In the method of manufacturing a focus adjusting apparatus for a camera according to the present invention, a lower thin film is formed on a substrate, the lower portion of the substrate is etched to form a reinforcement frame, a coil is formed on the lower thin film, and the reinforcement frame is etched. It characterized in that it comprises the step of floating the lower film.

Camera, variable focus, coil, magnet

Description

Control apparatus for focus of the camera and its manufacture method

1 is a conceptual diagram of an optical zoom camera module of a two-group lens system.

2 is a perspective view showing an operating state of the variable focus mirror according to the present invention;

3 is a view showing a manufacturing process of a variable focus mirror according to the present invention;

4 is a front process diagram of a variable focus mirror according to the present invention.

5 is a rear view of the variable focus mirror according to the present invention;

6 is a cross-sectional view of a variable focus mirror and a drive unit according to the present invention.

7 is an exploded perspective view of a variable focus mirror and a drive unit according to the present invention;

8 is a block diagram of a camera module using a variable focus mirror according to the present invention.

<Description of Symbols for Main Parts of Drawings>

30,63,65 ... Variable Focus Mirror 31 ... Board

32 ... reinforced frame 33 ...

34 Lower electrode 35 Insulation film

36.coil 37 ... through

38 ... reflective 62,64,66 ... optical system

67 ... image sensor

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a focusing apparatus capable of varying the focus of a camera lens, and a method of manufacturing the same.

Recently, with the development of communication technology and digital information processing technology, portable terminal technology in which various functions such as information processing and arithmetic, communication, image information input and output are integrated is emerging. Examples include PDAs (personal digital assistants) equipped with digital cameras and communication functions, digital cameras, and cellular phones equipped with PDA functions. Due to the development of digital camera technology and information storage capabilities, The mounting of digital camera modules is becoming more and more common.

In addition, as a mega pixel image sensor is used in a digital camera module mounted in a portable terminal, additional functions such as auto focus and optical zoom are becoming more important. . In order to realize autofocus and optical zoom in such a small digital camera module, a driver that can occupy a relatively small volume and satisfy performance such as high starting speed, low power consumption, and large displacement is required. In particular, there is a need for a driver that can cope with an increase in the required displacement due to the improvement of the optical zoom function. When moving, there are disadvantages such as complicated mechanism and friction of the gear part and noise. In addition, in the case of a driver using a stepping motor, it is difficult to manufacture a low-cost driver due to a complicated structure, and there is a limitation in size in miniaturization.

A first object of the present invention is to provide a variable focus mirror.

A second object of the present invention is to provide a variable focus mirror applied to a compact camera module.

It is a third object of the present invention to provide a method of manufacturing a variable focus mirror capable of adjusting the radius of curvature of a reflective surface.

A fourth object of the present invention is to provide a camera module for implementing an autofocus function using a variable focus head.

A fifth object of the present invention is to provide a camera module that provides an optical zoom function using a variable focus mirror.

A sixth object of the present invention is to provide a focus adjusting apparatus and a method of manufacturing the focus control apparatus capable of controlling the focus of the variable focus mirror by an electromagnetic force method.

Focusing apparatus of the camera according to the present invention for achieving the above object,

Board;

A lower thin film including a reflective surface at a lower portion thereof and stacked on the substrate;

It characterized in that it comprises a coil formed on the lower thin film.

Preferably, it comprises a lower electrode stacked on the lower thin film, and an insulating film stacked between the lower electrode and the coil.

Preferably, the lower portion of the substrate is characterized in that the through-hole for the optical path is formed in the area corresponding to the lower thin film.

Preferably, the lower portion of the substrate further comprises a driving unit for forming a magnetic field for the current flowing through the coil to change the refractive index of the lower thin film.

Preferably, the drive unit is characterized in that it comprises one or more permanent magnets facing the coil.

And, the focus control device of the camera according to the invention,

A variable focus mirror having a reflection surface and a coil stacked on the substrate, the variable focus mirror including a magnet facing the reflection surface below the substrate; And a variable focus control unit for adjusting a radius of curvature of the reflective surface by a magnetic field formed by a current applied to the coil.

Advantageously, said variable focus mirror comprises one or more on an optical path.

Preferably, the variable focus control unit is characterized in that to control the current intensity of the coil to adjust the focal length of the incident light.

On the other hand, the manufacturing method of the focus adjustment apparatus of the camera according to the present invention,

Forming a lower thin film on the substrate;

Etching a lower portion of the substrate to form a reinforcing mold;

Forming a coil on the lower thin film;

Etching the reinforcement frame is characterized in that it comprises a step of floating the lower film.

Referring to the accompanying drawings, a transfer control apparatus for a camera lens for a mobile terminal according to an exemplary embodiment of the present invention configured as described above is as follows.

1 is an exploded perspective view of an optical zoom camera module of a two-group lens system.

As shown in FIG. 1, the first lens group assembly 11 on which the first lens group 11a is mounted, the second lens group assembly 12 on which the second lens group 12a is mounted, and the lens The sensor unit 13 includes an image sensor 13a in which incident signals passing through the groups 11a and 12a are detected as electrical signals.

The camera module adjusts the distance between the first lens group 11a and the second lens group 12a according to the distance between the first lens group assembly 11 and the second lens group assembly 12. Therefore, the optical zoom and autofocus functions are implemented, and a signal incident through the second lens group 12a is detected as an electrical signal by the image sensor 13a of the sensor unit 13. The image of the image sensor 13a in this manner is determined.

In such a two-group lens type optical zoom camera module, the optical zoom lens group requires a relatively large displacement, and the auto focus lens group requires a quick start. With the enhancement of the zoom function and the image quality, the requirements for the movable part for operating the lens group assembly are complicated. In order to solve this problem, a variable focus mirror is provided, and the curvature adjustment of the reflective surface replaces the movement of the lens group by using the variable focus mirror.

2 (a) (b) (c) are perspective views of the variable focus mirror according to the present invention.

FIG. 2A is a configuration in which a reflective surface 21 is formed on a thin film 22 having a predetermined shape (for example, a circle, a square, etc.), and a central portion of the thin film 22 is supported by the reflective surface 21. Moved in the direction 24 or the lower direction 23, a change in curvature of the reflection surface 21 inside from the thin film 22 occurs. This change in curvature changes the focal length of the reflected light. (A) of FIG. 2 is a reflective surface in the initial state, and (b) and (c) of FIG. 2 are half of the variable focus mirror when the central portion of the reflective surface 21 causes a displacement of d1 or d2 downward. The slope curvature changes as r1 or r2, and thus the focal length of the reflected light changes.

The manufacturing method of such a variable focus mirror is as follows. 3A to 3F are views illustrating a method of manufacturing a variable focus mirror according to an exemplary embodiment of the present invention.

As shown in (a) and (b) of FIG. 3, the reinforcement frame 32 is manufactured on the rear surface of the substrate 31. The substrate 31 is, for example, a silicon substrate polished on both sides, and the reinforcement mold 32 formed on the rear surface (back side) of the substrate is formed by etching, for example, silicon deep reactive ion Silicon reinforced mold 32 is formed using Etch technology. The reinforcement frame 32 is preferably formed in a concave-convex shape, and the interval between adjacent concave-convex shapes or the shape of the entire concave-convex shape can be changed by the thickness of the mirror. The overall shape of the reinforcement mold may be made of one of concentric, radial, lattice, or a combination thereof.

As shown in FIG. 3C, the lower thin film 33 is stacked on the entire surface of the substrate 31. The lower electrode 34 and the insulating layer 35 are sequentially stacked on the lower thin film 33. Coil connecting grooves 35a and 35b are formed in the insulating layer 35 to provide a path for current with the lower electrode 34. The lower thin film 33 acts as a diaphragm. The lower thin film may be laminated before or after the reinforcement mold is manufactured.

As the material of the lower thin film 33 or the insulating film 35, a semiconductor such as a silicon nitride film or a silicon oxide film, a dielectric, a ceramic, a polymer, or the like may be used. have.

In other words, as the material of the lower thin film 33, various materials such as semiconductors such as silicon, silicon nitride, and silicon oxide, dielectrics, ceramics, polymers, and metals may be used. When the metal is used as the reflective film, the lower thin film 33 and the lower electrode 34 may be removed, and the lower thin film may be used as a current path. In addition, a material such as silicon nitride, silicon oxide, ceramic, or polymer may be used as the insulating layer 35. In addition, a metal layer may be used as the lower thin film 33, and an additional insulating film may be formed between the lower thin film 33 and the lower electrode 34.

As shown in FIG. 3E, a coil 36 is formed on the insulating film 35, and the coil 36 is formed on the insulating film 35 to form a current path with the lower electrode 34. The coil connection grooves 35a and 35b are formed to be connected to the lower electrode 34. Here, the coil connection grooves 35a and 35b are formed at the central portion 35a and the other end at the substrate end 35b so as to electrically connect both ends of the coil 36.

As the material of the coil 36 and the lower electrode 34 formed on the insulating layer 35, aluminum which may be formed using a process such as electroplating, sputtering, vacuum evaporation, or the like. All kinds of metals such as (Al), nickel (Ni), copper (Cu), chromium (Cr), gold (Au) and silver (Ag) can be used, and nonmetals such as indium tin oxide (ITO) or conductive polymers Conductors can also be used.

After completion of the coil formation process on the front surface of the substrate, the silicon reinforcement frame 32 on the rear surface of the substrate is removed as shown in FIG. 3 (e) (f) to float the diaphragm 33 on which the coil 36 is formed. That is, the substrate 31 in contact with the lower portion of the reinforcement frame 32 and the lower thin film 33 is removed, so that the lower portion of the lower thin film 33 is exposed by the through hole 37. Here, the etching process of the silicon reinforcing mold 32 uses an etching by XeF2 equipment which is a dry isotropic etching process. This process completes the variable focus mirror.

In the manufacture of such a variable focus mirror, a process of floating the lower thin film structure by dry etching having a high selectivity in the last step may be employed to obtain a high yield without damaging the surface of the lower thin film.

The reflective surface of the variable focus mirror is formed under the lower thin film 33 on the opposite side where the coil is formed. When the material of the lower thin film 33 is transparent, the lower electrode may be used as the reflective surface. In addition, a reflective film may be formed. As the reflective film material, a combination of a metal, a dielectric, and a laminate of a metal and a dielectric may be used.

4A, 4B, and 4C are cross-sectional views of a partial front surface of the variable focus mirror and cross-sectional views A-A ', B-B', and CC 'of the lower thin film 33 and the lower part of the substrate 31; When the electrode 34 is formed, the insulating film 35 is stacked on the lower electrode 34. The coil connecting grooves 35a and 35b communicating with the lower electrode 34 are formed at the center and one at the end of the insulating layer 35. Thereafter, the coil 36 is formed on the insulating layer 35 and the coil connection grooves 35a and 35b through a process such as electroplating. 39 is a driving pad for supplying power to the coil 36.

5A and 5B are rear view drawings of the variable focus mirror according to the present invention. In FIG. 5A, the silicon reinforcing mold 32 formed through the silicon anisotropic dry ion etch on the rear surface of the substrate 31 is separated into individual chips after completion of the coil formation process on the front surface, and isotropic silicon isotropic dry process. Etching equipment As an example, xenon fluoride (e.g. XeF2) or mixtures thereof will be removed with the associated etching equipment (Fig. 5b).

In this case, since the lower portion of the lower thin film 33 is exposed through the through hole 37 formed in the substrate 31, the process may be completed through an additional reflective film forming process on the bottom surface of the lower thin film 33 or may be formed on the diaphragm. The lower electrode can be used as the reflective film. The reflective surface or the reflective film may be formed in a circle, oval or polygon.

6 is a cross-sectional view illustrating the variable focus mirror 30 and the driving unit 50 capable of driving an electromagnetic force according to the present invention, and FIG. 7 is a perspective view of FIG. 6. 6 and 7, as shown in FIG. 6, the permanent magnet 51 for supplying the magnetic field is disposed on the opposite side of the through-hole 37 side of the lower thin film 33, which becomes the reflective surface 38, which is a permanent magnet. The lower thin film 33 is driven by a radial (radial or r direction) magnetic field by supplying the current 51 and the coil 36 to the current (+,-). Therefore, although one permanent magnet 51 may be used, the strength of the magnetic field may be significantly increased by using two magnets 51 and 52 and the support table 54 as shown. As shown in FIG. 7, the inner cylindrical magnet 51 is magnetized in the z direction M1, and the hollow cylindrical magnet 52 disposed at a predetermined distance 53 is disposed in the opposite direction of the z direction M2. When the support 54 is made of magnetized material and made of a material with high permeability in the lower part of the entire magnet region, the magnetic field in the radial direction r is significantly increased than using a single magnet. . In FIG. 7A, when a magnetic field is formed in the r direction and a current flows in the q direction in the coil 36, a Lorentz force in the z direction is applied to the lower thin film 33 on which the coil 36 is formed. .

When the lower thin film 33 is made of a material having a high light transmittance, the lower electrode 34 may be used as a reflecting surface, and as shown in FIG. 7, the reflecting surface is separately on the side of the through hole 37 of the lower thin film 33. (38) may be formed. As the material of the reflecting surface 39, a metal such as Al, Au, Ag, one or more dielectrics, or a combination thereof may be used. In the manufacturing process, the initial state of the reflective surface 38 can be controlled by adjusting the stresses of the lower thin film 33, the reflective surface 38, and the lower electrode 34. Initial deflection Without this, the reflective surface may be manufactured in a flat state or may be manufactured such that a predetermined initial deflection exists at the center of the reflective surface.

In the variable focus mirror according to the present invention, the lower thin film and the layers formed thereon control the radius of curvature in the optical path direction (that is, the optical axis) by the direction or intensity of the current applied to the coil by the variable focus controller. Focus adjustment and auto focus can be performed.

One or more such variable focusing devices may be installed on the light path.

8 is a block diagram of a camera module using a variable focus mirror according to an exemplary embodiment of the present invention. The incident light 61 is focused on the image sensor 67 via one or more lenses having optical properties. In this case, the optical path is refracted twice toward the vertically mounted image sensor 67, and the two variable focus mirrors 63 and 65 positioned in the refraction portion respectively perform focus adjustment and optical zoom functions. The optical system 64 located between the two varifocal mirrors 63 and 65 may use a lens, a reflecting surface, a filter, a mechanical shutter, an aperture, etc., and the front end of the varifocal mirror 1 63 and the varifocal mirror 2 (65). ) And an optical system 62, 66 suitable for the image sensor 67 may optionally be provided. Focus adjustment and optical zoom using the variable focus mirrors 63 and 65 according to the present invention can be selectively applied to a camera module using a conventional lens group shifting method, and the module can be configured with various optical paths. Do.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. It can be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

According to the apparatus for controlling a focus of a camera and a method of manufacturing the same according to the present invention, an optical zoom or focus adjustment function is performed by a driver using various actuators, such as a conventional step motor, without a separate actuator or driving mechanism, unlike a camera module. By implementing the focus variable mirror in the, there is an effect suitable for compact, lightweight.

In addition, the manufacturing process of the variable focus mirror adopts a process of floating the diaphragm structure by dry etching with a high selectivity in the last step, so that a high yield can be obtained without damaging the diaphragm surface.

In addition, it can meet the required performance while occupying the minimum space, and is expected to be suitable for various portable devices such as PDA, mobile phone and portable terminal.

Claims (24)

Board; A lower thin film including a reflective surface at a lower portion thereof and stacked on the substrate; Focusing device of the camera, characterized in that it comprises a coil formed on the lower thin film. The method of claim 1, And a lower electrode stacked on the lower thin film, and an insulating layer stacked between the lower electrode and the coil. The method of claim 1, Focusing apparatus of the camera, characterized in that the through hole for the optical path is formed in the area corresponding to the lower thin film on the bottom surface of the substrate. The method of claim 1, And a driver configured to form a magnetic field with respect to an electric current flowing through the coil in a lower portion of the substrate to vary the refractive index of the lower thin film. The method of claim 4, wherein And the driving unit includes at least one permanent magnet facing the coil. A variable focus mirror having a reflection surface and a coil stacked on the substrate, the variable focus mirror including a magnet facing the reflection surface below the substrate; And a variable focus control unit for adjusting a radius of curvature of the reflective surface by a magnetic field formed by a current applied to the coil. The method of claim 6, And the variable focus mirror comprises one or more on the optical path. The method of claim 6, The variable focus controller controls the current intensity of the coil to adjust the focal length of the incident light. Forming a lower thin film on the substrate; Etching a lower portion of the substrate to form a reinforcing mold; Forming a coil on the lower thin film; Etching the reinforcement frame to float the bottom thin film manufacturing method of the camera comprising the step of floating. The method of claim 9, Method for manufacturing a focus of the camera, characterized in that the reflecting surface is formed on the bottom surface of the lower thin film. The method of claim 9, And the lower thin film is at least one of a dielectric, a polymer, a ceramic, or a metal. The method of claim 9, The reinforcement frame is a method of manufacturing a focusing apparatus of a camera, characterized in that the etching of one of concentric circles, radial, grating, combinations thereof. The method of claim 9, The focus of the camera, characterized in that the coil is formed of one or a combination of metals of aluminum (Al), nickel (Ni), copper (Cu), chromium (Cr), gold (Au), silver (Ag). How to make control device. The method of claim 9, The coil is made of a non-metal or a combination thereof, such as indium tin oxide (ITO), a conductive polymer, or a combination thereof. The method of claim 9, The step of floating the lower thin film by etching the reinforcement frame, a method of manufacturing a focus control apparatus for a camera, characterized in that using an isotropic dry etching process. The method of claim 9, The reflecting surface is a method of manufacturing a focus adjusting apparatus of the camera, characterized in that any one of a circle, oval, or polygon. The method of claim 9, And the reflective surface is formed of a metal, a dielectric, or a laminated structure of a metal and a dielectric. The method of claim 9, Forming a lower electrode between the lower thin film and the coil, and forming an insulating layer stacked to be partially connected between the lower electrode and the coil. The method of claim 18, The lower thin film and the insulating film are each made of any one of a dielectric such as silicon nitride (silicon nitride), silicon oxide (silicon oxide), ceramic (ceramic), a polymer (polymer), characterized in that the manufacturing method of the focusing apparatus of the camera. The method of claim 9, And a curvature radius of the lower thin film is changed by a magnetic field generated between the coil and the permanent magnet facing the coil by a current applied to the coil. Forming a diaphragm on the substrate; Stacking a coil on the diaphragm; And forming a reflecting surface on a bottom surface of the diaphragm under the substrate. The method of claim 21, Before or after forming the diaphragm on the substrate to form a reinforcement mold by etching the lower part of the substrate, and removing the formed reinforcement mold after coil lamination, respectively. . The method of claim 21, Forming a lower electrode between the diaphragm and the coil, and forming an insulating film laminated to be partially connected between the lower electrode and the coil. The method of claim 21, And disposing one or more permanent magnets generating electromagnetic force between the diaphragm and the coil on one side of the substrate, wherein the diaphragm and the coil are stacked.

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