KR20090065854A - Auto focusing apparatus of camera module and auto focusing method thereof - Google Patents

Abstract

A device and a method for processing auto-focusing of a camera module are provided to process auto-focusing quickly, precisely, and conveniently in assembly of the camera module. A camera module is mounted to a focus control jig of a substrate section(S110). A lens barrel of the camera module is transferred by driving a driving part of focus control jig. A spot size, which corresponds to a distance between a lens of the lens barrel and a light source, of the light source is measured and calculated(S130). The focus of the camera module is adjusted by controlling the driving part through the spot size of the light source(S140).

Description

Auto focusing apparatus of camera module and auto focusing method

The present invention relates to an automatic focusing apparatus and an automatic focusing method of a camera module, and more particularly, to make the focusing of the camera module more quickly, accurately, and conveniently during assembly production of the camera module, thereby increasing productivity and reliability of the camera module. It relates to an automatic focusing device and an automatic focusing method of the camera module to improve the.

Nowadays, portable terminals such as mobile phones and PDAs are being used as a multi-convergence with music, movies, TV, and games as well as simple telephone functions with the development of the technology. The camera module is the most representative. The camera module is changing from the existing 300,000 pixels (VGA level) to the high pixel center of 7 million pixels and is being changed to implement various additional functions such as auto focusing (AF) and optical zoom.

In general, the camera module (CCM: COMPACT CAMERA MOUDULE) is compact and is applied to various IT devices such as a camera phone, a PDA, a smartphone, and a portable mobile communication device such as a toy camera (TOY CAMERA). Increasingly, devices equipped with small camera modules are gradually being released to meet various consumer tastes.

Such a camera module is manufactured using an image sensor such as a CCD or a CMOS as a main component, and collects an image of an object through the image sensor and stores it as data in a memory in the device, and the stored data is stored in the LCD or PC in the device. The image is displayed through a display medium such as a monitor.

A typical camera module is typically produced by a method such as COB (CHIP ON BOARD), COF (CHIP ON FLEXIBLE), a brief look at the typical structure of the COB method with reference to the drawings shown below as follows. .

1 is an exploded perspective view of a COB type camera module, Figure 2 is a schematic cross-sectional view showing a COB type camera module, the conventional camera module 10 is a CCD or CMOS image sensor 12 is mounted by a wire bonding method The printed circuit board 11 is coupled to the lower portion of the plastic housing 13, and the lens barrel 16, which extends the cylindrical body 15 downward, is coupled to the barrel 14 extending above the housing 13. Is produced by

The camera module 10 has a housing 13 and a lens barrel 16 formed by screwing a female screw portion 14a formed on the inner circumferential surface of the barrel 14 and a male screw portion 15a formed on the outer circumferential surface of the cylindrical body 15. Combined.

In this case, an IR filter 18 is disposed between the upper surface of the printed board 11, that is, the lens L mounted on the lower end of the lens barrel 16 and the image sensor 12 attached to the lower surface of the printed board 11. By being combined, the infrared rays of excessive long wavelength flowing into the image sensor 12 are blocked.

In the camera module assembled as described above, light flowing from a specific object passes through the lens L and the image is inverted to focus on the surface of the image sensor 12. While rotating the lens barrel 16, an adhesive is injected between the housing 13 and the lens barrel 16 at the point where the optimal focus is achieved, and the housing 13 and the lens barrel 16 are adhesively fixed to the final camera. Modular products are produced.

The camera module 10 having the structure as described above rotates the lens barrel 16 in which the lens L corresponding to the image sensor 12 mounted on the bottom surface of the housing 13 is mounted left and right. In order to determine the correct focus of the lens L in the light receiving area of the sensor 12, the operator visually checks the image captured by the image sensor 12 and the image sensor (until the captured image is clear). 12) and a distance between the lens L and the housing 13 and the lens barrel so that the position of the lens L is fixed when the image captured by the image sensor 12 is maximally clear. 16) adhesive fixation is made.

In addition, a resolution chart (not shown) is placed on the lens barrel 16 coupled to the upper portion of the housing 13, and the image of the resolution chart is captured by the image sensor 12. Is extracted so that the focus adjustment is performed by comparing the extracted contrast values.

However, when relying on the visual inspection of the operator to focus the camera module during such assembly, the measurement criteria vary depending on the operator's proficiency, fatigue level, or resolution chart used as a reference table. Not only cause the defect but also have to rely on the manual labor of the worker one by one, there is a problem that the work speed is significantly slowed productivity is lowered.

Accordingly, the present invention was devised to solve the above-mentioned disadvantages and problems in the manufacturing process of the conventional camera module, and an object of the present invention is to more quickly and accurately adjust the focus of the camera module during assembly production of the camera module. It is to provide an automatic focusing device and an automatic focusing control method of the camera module that can be made to be convenient to improve the productivity and reliability of the camera module.

According to one embodiment of the present invention for achieving the above object, a light source; A camera module including a lens barrel having a lens into which light emitted from the light source is incident; A substrate portion having the camera module mounted thereon and having a focusing jig provided with a driving portion for transferring the lens barrel of the camera module in the optical axis direction; A numerical calculation unit for measuring and calculating an image spot size of the light source implemented through the camera module when the lens barrel is transferred; And a driving control unit for controlling the focus of the camera module by controlling the driving unit through the spot size of the light source calculated by the numerical calculation unit.

The automatic focusing device may further include a collimating lens unit installed on an optical axis path between the light source and the camera module to compensate for a measurement distance between the light source and the camera module.

In addition, the automatic focusing apparatus may further include a position adjusting unit for adjusting the position of the light source.

The light source is made of an infrared LED, the camera module is preferably made of a camera module capable of infrared recognition.

On the other hand, according to another aspect of the present invention for achieving the above object, an installation step of mounting the camera module to the focusing jig of the substrate portion; A scanning step of driving the driving unit of the focusing jig to transfer the lens barrel of the camera module and measuring and calculating the spot size of the light source according to the distance between the lens mounted on the lens barrel and the light source; And a focus adjusting step of adjusting the focus of the camera module by controlling the driving unit through the spot size of the light source.

The automatic focus adjustment method may further include a correction step performed after the installation step and adjusting a collimating lens unit to compensate a focus measurement distance between the light source and the camera module.

In the scanning step, the lens barrel of the camera module is preferably transferred in a direction away from the light source.

Here, the scanning step may be completed when the lens barrel of the camera module is transferred to the maximum.

In addition, the scanning step may be calculated by measuring the spot size in a set step, but may be completed if the current measured spot size of the light source is larger than the size of the previously measured spot size corresponding to the set number of times.

The focus adjusting step may be a step of adjusting the focus of the camera module by transferring the lens barrel to a position where the spot size of the light source measured in the scanning step has a minimum value.

As described above, according to the automatic focusing device and the automatic focusing method of the camera module according to the present invention, there is an effect that the focusing of the camera module can be made more quickly, accurately and conveniently during assembly production of the camera module. .

In addition, through the above advantages there is an effect that can improve the productivity and reliability of the camera module.

Hereinafter, preferred embodiments of an automatic focusing apparatus and an automatic focusing method of a camera module according to the present invention will be described in more detail with reference to the accompanying drawings.

Camera Focus Auto Focusing Device

First, with reference to the accompanying Figure 3 will be described with respect to the automatic focus adjustment apparatus of the camera module according to an embodiment of the present invention.

Figure 3 is a schematic cross-sectional view of the inner portion of the automatic focusing apparatus of the camera module according to the present invention.

As shown in Figure 3, the automatic focusing device of the camera module according to an embodiment of the present invention, the rectangular box-shaped light box 100, and the light source installed inside the light box (100) A camera module 140 including a lens barrel (not shown) having a built-in 110 and a lens (not shown) into which light emitted from the light source 110 is incident, and the camera module 140 is mounted. The substrate unit 160 having a focusing jig 150 installed with a driving unit (not shown) for transferring the lens barrel of the camera module 140 in the optical axis direction, and the camera module 140 when the lens barrel is transferred. The numerical operator (not shown) for measuring and calculating the spot size of the light source 110 implemented through the control unit, and the driving unit is controlled by the spot size of the light source 110 calculated by the numerical operator Focus of camera module 140 It is configured to include a drive control unit (not shown) for adjustment.

Here, a position adjusting unit 120 connected to the light source 110 may be installed at an upper side of the light box 100 to adjust the position of the light source 110.

In addition, the light source 110 is made of an infrared LED, and thus the camera module 140 is preferably made of a camera module capable of infrared recognition.

On the other hand, on the optical axis path between the light source 110 and the camera module 140 inside the light box 100, collimating to compensate the measurement distance between the light source 110 and the camera module 140 The lens unit 130 may be installed.

That is, the focusing operation of the camera module 140 is performed in the inner space of the light box 100, and the inner space of the light box 100 which is the focusing work space of the camera module 140 is limited. Therefore, the collimating lens unit 130 is installed to increase the required distance for the focusing operation as compared with the actual distance between the light source 110 and the camera module 140.

As a result, the collimating lens unit may be adjusted in a limited internal space of the light box 100 to secure a focusing working distance between the light source 110 and the camera module 140.

On the other hand, the numerical operation unit and the driving control unit may be configured as a chip mounted on the substrate unit 160, or may be configured as a device such as a separate PC terminal connected to the substrate unit 160.

Auto Focusing Method of Camera Module

Next, with reference to the accompanying Figures 4 and 5 will be described the automatic focus adjustment method of the camera module according to an embodiment of the present invention.

4 is a block diagram illustrating an automatic focus adjusting method of a camera module according to an exemplary embodiment of the present invention, and FIG. 5 is a graph showing a spot size of a light source according to a distance between a light source and a lens.

As shown in Figure 4, the automatic focus adjustment method of the camera module according to an embodiment of the present invention, the installation step (S110), correction step (S120), scanning step (S130), and focus adjustment step ( S140) is configured.

The automatic focusing method will be described in more detail. First, the camera module 140 (see FIG. 3) to be focused on the focusing jig 150 (see FIG. 3) of the substrate unit 160 (see FIG. 3). (S110)

After mounting the camera module 140 as described above, in order to correct the distance between the light source 110 and the lens required for the focusing operation of the camera module 140, the collimating lens unit 130 (see Fig. 3). (S120)

Then, when the automatic focusing of the camera module 140 is performed, the driving unit installed in the focusing jig 150 is driven to transfer the lens barrel of the camera module 140 in a direction away from the light source 110.

In this case, when the lens barrel of the camera module 140 is coupled to the housing in a screw manner, the lens barrel may be rotated by driving the driving unit to transfer the lens barrel.

At the same time, as shown in FIG. 5, the numerical operation unit determines a variable spot size of the light source 110 according to a variable distance between the light source 110 and the lens mounted on the lens barrel according to the movement of the lens barrel. Measure and calculate. (S130)

When the lens barrel of the camera module 140 is transferred to the maximum, the feeding of the lens barrel is stopped and thus the scanning step is completed.

Next, when the scanning step is completed, the driving control unit transfers the lens barrel to a position having the minimum value Min among the spot sizes of the light source 110 measured and measured in the scanning step of the camera module 140. Adjust the focus.

Meanwhile, instead of measuring and calculating the spot size of the light source 110 according to the distance between the light source 110 and the lens until the lens barrel of the camera module 140 is transferred to the maximum in the scanning step, the The focus of the camera module 140 may be adjusted by minimizing the transfer process of the lens barrel.

That is, referring to FIG. 5, the spot size of the light source 110 measured and measured in the scanning step in which the lens barrel of the camera module 140 is transferred to the maximum tends to gradually decrease and increase again from the point having the minimum value. .

Therefore, the spot size of the light source 110 is measured and calculated while transferring the lens barrel of the camera module 140 to the set step, and the current measured spot size of the light source 110 is determined by the spot size measured before. If the size is larger than the set number (for example, two or three times), the minimum value Min of the spot size of the light source 110 is determined.

Accordingly, it is determined that the minimum value of the spot size of the light source 110 is identified as described above, and the lens barrel is transferred to a position having the minimum value Min among the spot sizes of the light source 110 measured and measured up to this point. The focus of the camera module 140 is adjusted.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be possible, but such substitutions, changes and the like should be regarded as belonging to the following claims.

1 is an exploded perspective view of a COB type camera module.

2 is a cross-sectional view schematically showing a COB type camera module.

Figure 3 is a schematic cross-sectional view showing an automatic focusing apparatus of the camera module in an embodiment of the present invention.

Figure 4 is a block diagram showing an automatic focus adjustment method of the camera module according to an embodiment of the present invention.

5 is a graph showing the spot size of the light source according to the distance between the light source and the lens.

Explanation of symbols on the main parts of the drawings

100: light box 110: light source

120: position adjustment unit 130: collimating lens unit

140: camera module 150: jig for adjusting the focus

160: substrate portion

Claims (10)

Light source; A camera module including a lens barrel having a lens into which light emitted from the light source is incident; A substrate portion having the camera module mounted thereon and having a focusing jig provided with a driving portion for transferring the lens barrel of the camera module in the optical axis direction; A numerical calculation unit for measuring and calculating an image spot size of the light source implemented through the camera module when the lens barrel is transferred; And A driving control unit controlling the focus of the camera module by controlling the driving unit through the spot size of the light source calculated by the numerical calculation unit; Automatic focusing device of the camera module comprising a. The method of claim 1, And a collimating lens unit disposed on an optical axis path between the light source and the camera module to compensate for a measurement distance between the light source and the camera module. The method of claim 1, Auto focusing apparatus of the camera module further comprises a position adjusting unit for adjusting the position of the light source. The method according to claim 1 or 3, The light source is made of an infrared LED, the camera module is auto focusing apparatus of the camera module, characterized in that made of a camera module capable of infrared recognition. An installation step of attaching the camera module to the focusing jig of the substrate unit; A scanning step of driving the driving unit of the focusing jig to transfer the lens barrel of the camera module and measuring and calculating the spot size of the light source according to the distance between the lens mounted on the lens barrel and the light source; And A focus adjusting step of adjusting the focus of the camera module by controlling the driving unit through the spot size of the light source; Auto focusing method of the camera module comprising a. The method of claim 5, And a correction step performed after the installation step and adjusting a collimating lens unit to compensate for a focus measurement distance between the light source and the camera module. The method of claim 5, In the scanning step, the lens barrel of the camera module is moved in a direction away from the light source Auto focus adjustment method of the camera module. The method of claim 5, And the scanning step is completed when the lens barrel of the camera module is transferred to the maximum. The method of claim 5, The scanning step is calculated by measuring the spot size in a set step, and is completed when the current measured spot size of the light source is larger than the size of the previously measured spot size corresponding to the set number of times. How to auto focus the module. The method of claim 5, The focus adjusting step is a step of adjusting the focus of the camera module by moving the lens barrel to a position where the spot size of the light source measured in the scanning step has a minimum value. .

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