Camera module inspection system and method for operating the same

A camera module inspection system and a method for operating the inspection system. More specifically, the inspection system can quickly check and correct the alignment of the camera module.

RELATED APPLICATION DATA

This application claims the benefit of Korean Patent Application No. KR 10-2022-0074262, filed Jun. 17, 2022, the content of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure relates to a camera module inspection system and a method for operating the inspection system. More specifically, the inspection system can quickly check and correct the alignment of the camera module.

2. Description of Related Art

With the development of smart devices, the use of small camera modules is rapidly increasing. Recently, camera modules have been installed not only in portable terminals such as smart phones, tablet PCs and laptops, but also in automobiles and smart TVs.

A typical camera module includes a housing, a lens barrel in which a plurality of lenses are stacked, a CCD or CMOS image sensor, and a connector electrically connecting a board on which they are mounted and the outside.

In the process of assembling the camera module, parts of the camera module must be transferred to a plurality of assembly devices. In addition, the camera module must be transferred to a plurality of inspection devices that perform specific inspections to inspect whether the assembly is properly performed or whether the AF (Auto Focus) or OIS (Optical Image Stabilization) of the camera module operates correctly. A plurality of assembly devices may perform assembly by receiving the parts of the camera module having a predetermined orientation for assembly.

However, the alignment of the camera modules may be disturbed in the process of being transported, and when the alignment of the camera modules with respect to the inspection device or the assembly device is disturbed, inspection or assembly may not be performed properly. In addition, when inspection or assembly is attempted while the alignment is disturbed, a strain is applied to the camera module, and the camera module may be damaged.

Conventionally, in order to align the camera module and the inspection device or assembly device, a method of aligning the camera module by inserting it into a mechanical frame at a predetermined position has been used in some cases. However, since the inspection device or the assembly device includes many parts, the mechanical coupling becomes loose over time, resulting in a high defect rate.

SUMMARY OF THE INVENTION

The camera module inspection system according to one embodiment of the present disclosure comprises a control unit, an alignment camera, an alignment stage, and a support socket, and the method for operating the inspection system includes obtaining an image of the camera module by photographing a predetermined region of the camera module above the support socket by the alignment camera, comparing the image of the camera module with the first pattern image to obtain a position of a first point included in the image of the camera module, comparing the image of the camera module with a second pattern image to obtain a position of a second point included in the image of the camera module, and obtaining a central position of the position of the first point and the position of the second point, obtaining an alignment line connecting the position of the first point and the position of the second point, obtaining a difference vector between the center position and a predetermined reference position, obtaining a rotation angle between the alignment line and a predetermined reference line, and driving the alignment stage based on at least one of the difference vector and the rotation angle so that the center position is located at the reference position and the alignment line coincides with a predetermined reference line.

The inspection system according to one embodiment of the present disclosure includes a base unit constituting a framework of the inspection system, an alignment stage coupled to the upper side of the base unit and for determining the direction of the support socket, a support socket coupled to the upper side of the alignment stage and for supporting the camera module, an alignment camera spaced apart from the upper side of the support socket by a predetermined distance and fixed at a predetermined position in order to photograph an alignment state of the camera module placed on the support socket, an inspection board driving unit coupled to an upper side of the base unit, positioned in a first direction of the alignment stage, and configured to move an inspection board in the first direction or in a direction opposite to the first direction, and an inspection board coupled to the upper side of the inspection board driving unit and for inspecting the camera module on the support socket, and wherein the first direction is a direction parallel to the ground.

The inspection system according to one embodiment of the present disclosure discloses that the alignment stage may include a first stage coupled to an upper side of the base unit to move the support socket in a second direction or in a direction opposite to the second direction, a second stage coupled to an upper side of the first stage to move the support socket in the first direction or in a direction opposite to the first direction and a third stage coupled to the upper side of the second stage to rotate the support socket about an axis perpendicular to the ground and wherein the first direction and the second direction are perpendicular to each other.

The method of operating an inspection system according to one embodiment of the present disclosure discloses that the first pattern image and the second pattern image include a positioning point at a predetermined position, and wherein obtaining the position of the first point comprises determining a first region most similar to a first pattern image in the image of the camera module and obtaining a position in the first region corresponding to the position of the positioning point of the first pattern image as the position of the first point, wherein obtaining the position of the second point comprises determining a second region most similar to a second pattern image in the image of the camera module and obtaining a position in the second region corresponding to the position of the positioning point of the second pattern image as the position of the second point, and wherein the second pattern image is a mirror image or an image rotated by 180 degrees of the first pattern image.

The method of operating an inspection system according to one embodiment of the present disclosure discloses that obtaining a position within the first region as the position of the first point comprises outputting a signal indicating that there is an abnormality in the camera module when the similarity between the first region and the first pattern image is less than a predetermined threshold similarity; and obtaining a position in the first region corresponding to the position of the positioning point of the first pattern image as the position of the first point contains steps, when the similarity between the first region and the first pattern image is greater than or equal to the threshold similarity, and wherein obtaining a position in the second region as the position of the second point comprises outputting a signal indicating that there is an abnormality in the camera module when the similarity between the second region and the second pattern image is less than the threshold similarity and obtaining a position in the second region corresponding to the position of the positioning point of the second pattern image as the position of the second point, when the similarity between the second region and the second pattern image is greater than or equal to the threshold similarity.

The method of operating an inspection system according to one embodiment of the present disclosure comprises determining a difference distance between the position of the first point and the position of the second point after the step of obtaining the position of the second point, determining an absolute value of a difference between the difference distance and a predetermined basic distance, outputting a signal indicating that there is an abnormality in the camera module when the absolute value is greater than or equal to a predetermined tolerance, and obtaining the center position or the alignment line when the absolute value is less than a predetermined tolerance.

The method of operating an inspection system according to one embodiment of the present disclosure discloses that a first inspection board alignment point and a second inspection board alignment point are displayed on the upper side of the inspection board, and the method of operating an inspection system comprises moving the inspection board in a direction opposite to the first direction by using the inspection board driving unit, obtaining an image of the inspection board using the alignment camera, determining the position of the first inspection board alignment point and the second inspection board alignment point in the image of the inspection board, determining the center of the position of the first inspection board alignment point and the position of the second inspection board alignment point as the reference position, determining a line connecting the position of the first inspection board alignment point and the position of the second inspection board alignment point as the reference line, moving the inspection board in the first direction by using the inspection board driving unit, and obtaining an image of the camera module by the alignment camera photographing a predetermined region of the camera module on the support socket.

The method of operating an inspection system according to one embodiment of the present disclosure comprises moving the inspection board in a direction opposite to the first direction by using the inspection board driving unit after the step of driving the alignment stage, moving the inspection board downward to couple the camera module and the inspection board on the support socket, obtaining a test result by testing the camera module using the inspection board, separating the camera module and the inspection board by moving the inspection board upward, and moving the inspection board in the first direction by using the inspection board driving unit.

In addition, a program for implementing the above-described operating method of the inspection system may be recorded on a computer-readable recording medium.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Advantages and features of the disclosed embodiments, and methods of achieving them, will become clear with reference to the following embodiments in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various forms, only the present embodiments make the present disclosure complete, and those of ordinary skill in the art to which the present disclosure belongs It is provided only to fully inform the person of the scope of the invention.

Terms used in this specification will be briefly described, and the disclosed embodiments will be described in detail.

The terms used in this specification have been selected from general terms that are currently widely used as much as possible while considering the functions in the present disclosure, but they may vary according to the intention of a person skilled in the related field, a precedent, or the emergence of new technologies. In addition, in a specific case, there is also a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the invention. Therefore, terms used in the present disclosure should be defined based on the meaning of the term and the overall content of the present disclosure, not simply the name of the term.

Expressions in the singular number in this specification include plural expressions unless the context clearly dictates that they are singular. Also, plural expressions include singular expressions unless the context clearly specifies that they are plural.

When it is said that a certain part “includes” a certain component throughout the specification, it means that it may further include other components, not excluding other components unless otherwise stated.

Also, the term “unit” used in the specification means a software or hardware component, and “unit” performs certain roles. However, “unit” is not meant to be limited to software or hardware. A “unit” may be configured to reside in an addressable storage medium and may be configured to reproduce on one or more processors. Thus, as an example, “unit” can refer to components such as software components, object-oriented software components, class components and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. Functionality provided within components and “parts” may be combined into fewer components and “parts” or further separated into additional components and “parts”.

According to an embodiment of the present disclosure, “unit” may be implemented as a processor and a memory. The term “processor” should be broadly interpreted to include general-purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), controllers, microcontrollers, state machines, and the like. In some circumstances, “processor” may refer to an application specific integrated circuit (ASIC), programmable logic device (PLD), field programmable gate array (FPGA), or the like. The term “processor” may also refer to a combination of processing devices, such as, for example, a combination of a DSP and a microprocessor, a combination of a plurality of microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The term “memory” should be broadly interpreted to include any electronic component capable of storing electronic information. The term memory includes random access memory (RAN), read-only memory (ROM), non-volatile random access memory (NVRAM)), programmable read-only memory (PROM), erasable-programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic or optical data storage, various types of processor-readable media, such as registers, and the like. A memory is said to be in electronic communication with the processor if the processor can read information from and/or write information to the memory. Memory integrated with the processor is in electronic communication with the processor.

Hereinafter, with reference to the accompanying drawings, embodiments will be described in detail so that those skilled in the art can easily carry out the embodiments. And in order to clearly describe the present disclosure in the drawings, parts irrelevant to the description are omitted.

FIG.1discloses a hardware configuration of a control unit according to an embodiment of the present disclosure.

The inspection system for inspecting the camera module200may include a control unit100for controlling the operation of the inspection system. The control unit100may include a processor110and a memory120. The processor110executes instructions stored in the memory120. The control unit100may control movement of components included in the inspection system based on commands stored in the memory120. The control unit100may be implemented in hardware or software. The control unit100may be implemented only with hardware for performing a corresponding function. However, it is not limited thereto, and the control unit100may be implemented as a general-purpose processor110, and the general-purpose processor110of the control unit100may be implemented to execute a program stored in the memory120. Hereinafter, components included in the inspection system will be described, and a process for the control unit100to control various components included in the inspection system will be described.

FIG.2is a drawing showing hardware of an inspection system according to an embodiment of the present disclosure.FIG.3is a drawing showing hardware of an inspection system according to an embodiment of the present disclosure.

Since the control unit100has already been described, the remaining hardware constituting the inspection system200will be described in more detail below.

Referring toFIGS.2and3, the inspection system200may include a base unit250forming a skeleton of the inspection system200. The base unit250may be implemented with a metal material. In addition, the base unit250may include an inspection board accommodating unit311for accommodating the inspection board240and a stage accommodating unit312for accommodating the alignment stage220. An upper surface of the inspection board accommodating unit311may be located higher than an upper surface of the stage accommodating unit312. Since the stage accommodating unit312is positioned lower, a space for positioning a camera for aligning the position of the camera module or an inspection board for inspecting the camera module above the camera module may be secured. In addition, since all the devices for alignment and inspection are located above the camera module, the moving distance of the devices is shortened and the inspection time is shortened, thereby increasing inspection efficiency.

A space may be formed between the lower surface and the upper surface of the inspection board accommodating unit311. The control unit100may be disposed in the space formed in the inspection board accommodating unit311. The control unit100may receive data from the server or transmit data to the server. The control unit100may control the operation of at least one of the alignment camera210and the alignment stage220. The space formed between the lower surface and the upper surface of the inspection board accommodating unit311may not have a side surface. That is, the control unit may be disposed inside an open space rather than inside a closed space. Therefore, heat emitted from the control unit100and heat generated from the inspection system200can be quickly released. In the inspection system200, the cooling efficiency may be increased by arranging a heat dissipation fan in a space formed between the lower surface and the upper surface of the inspection board accommodating unit311. Since the inspection system200of the present disclosure uses a lot of image processing, the processing capability of the control unit100is greatly required, and the temperature of the control unit100increases, so that the control unit100may slow down due to throttling. However, it is possible not to worry about throttling of the control unit100by the above structure. Since the heat generated from the control unit100is not dissipated toward the camera module, it is possible not to affect the accuracy and speed of inspection.

The inspection system200may include an alignment stage220. The alignment stage220may be coupled to the upper side of the base unit250. More specifically, the alignment stage220may be coupled to the upper side of the stage accommodating part312. The alignment stage220may be configured to determine the direction of the support socket230.FIG.4is briefly referred for r a description of the alignment stage220.

FIG.4is a drawing showing an alignment stage according to an embodiment of the present disclosure.

The alignment stage220may include a first stage410, a second stage420, and a third stage430.

The first stage410may be coupled to the upper side of the base unit250. The first stage410may be configured to move the support socket230in a second direction or in a direction opposite to the second direction. Hereinafter, the first stage410will be mainly described as being configured to move the support socket230in a second direction or in a direction opposite to the second direction. However, it is not limited thereto, and the first stage410may be configured to move the support socket230in a first direction or in a direction opposite to the first direction. The first direction and the second direction may be directions parallel to the ground, and the first direction and the second direction may be perpendicular to each other.

The first stage410may include a base stage coupled to the base unit250. A second direction guide rail may be formed above the base stage. The second direction guide rail may extend in the second direction. The first stage410may include a second direction movement stage on the base stage. A lower side of the second direction movement stage may include a slider. The slider of the second direction movement stage is coupled to the second direction guide rail of the base stage to slide in a second direction or in a direction opposite to the second direction. A first direction guide rail may be formed above the second direction movement stage. The first direction guide rail may extend in the first direction. The first direction guide rail may be configured to move the second stage420in a first direction or in a direction opposite to the first direction.

The second stage420may be coupled to an upper side of the first stage to move the support socket in a first direction or in a direction opposite to the first direction. A slide may be included on the lower side of the second stage420. The slider of the second stage420is coupled to the first direction guide rail of the second direction movement stage and can slide in a first direction or in a direction opposite to the first direction. As already described, the second direction movement stage may be included in the first stage410.

In the present disclosure, the second stage420is described as configured to move the support socket in a first direction or in a direction opposite to the first direction but is not limited thereto. The second stage420may be configured to move the support socket230in a second direction or in a direction opposite to the second direction.

The third stage430may be coupled to the upper side of the second stage to rotate the support socket about an axis perpendicular to the ground. As such, since the inspection system of the present disclosure includes the first stage410, the second stage420, and the third stage430, the camera module to be inspected can be accurately positioned. Accordingly, damage to the connector of the camera module can be minimized. In addition, only the camera module needs to be aligned in an accurate position, and the other components move to a predetermined position to perform the inspection, so the inspection speed can be increased.

The movement of the first stage410, the second stage420, and the third stage430may be controlled by the control unit100. Also, each of the first stage410, the second stage420, and the third stage430may include a driving unit. The driving unit may include at least one of a fluid cylinder and an electric motor. The first stage410, the second stage420, and the third stage430can be independently driven by the control unit100. Each of the first stage410, the second stage420, and the third stage430may include an encoder. The control unit100may measure the position of the camera module in the first direction and the position of the camera module in the second direction, the rotation position of the camera module about an axis perpendicular to the ground based on the encoders included in the first stage410, the second stage420, and the third stage430, respectively. In addition, the control unit100may measure positions after movement by the driving unit by means of encoders included in the first stage410, the second stage420, and the third stage430, respectively.

The size (width, depth, height) of the first stage410and the second stage420may be approximately 70×70×25 mm. The maximum force of the driving units of the first stage410and the second stage420may be about 36N. Also, the resolution may be approximately 0.1 um (micrometer), and the maximum speed may be approximately 270 mm/s.

The size of the third stage430may be approximately 70×82×25 mm. The maximum torque of the third stage430may be about 0.6 Nm. Also, the resolution may be approximately 5847 pulse/degree, and the maximum speed may be approximately 720 degree/s.

Referring toFIG.3, the upper surface of the third stage430and the upper surface320of the inspection board accommodating unit311may have substantially the same height.

Referring toFIGS.2and3, the inspection system200may include a support socket230. The support socket230is coupled to the upper side of the alignment stage220and may be configured to support the camera module. More specifically, the support socket230may be fixed to an upper end of the third stage430. The support socket230may move in a first direction, in a direction opposite to the first direction, in a second direction, or in a direction opposite to the second direction by the first stage410to the third stage430or may rotate clockwise or counterclockwise about an axis perpendicular to the ground.

The inspection system200may include an alignment camera210. The alignment camera210may be spaced apart from the upper side of the support socket230by a predetermined distance. Since no other equipment is provided on the upper side of the support socket230and the alignment camera210can be separated by a sufficient distance from the support socket230, a relatively inexpensive camera can be used. Conventionally, since the positions of the inspection equipment as well as the camera module had to be measured, there was a case where the alignment camera210was located below the support socket230, and there was a case where a close-up camera was needed because there was not enough space at the bottom, in this case, a relatively expensive camera was used.

Alignment camera210may be configured to photograph the alignment state of the camera module placed on the support socket, and may be secured at a predetermined position. When the manager initially determines the location of the alignment camera210, the location of the alignment camera210may not be changed unless there are special circumstances. A special circumstance may be a case where a long time has passed since the alignment camera210was initially fixed, or a position of the alignment camera210has been changed by an external force. Since the position of the alignment camera210is fixed in this way, the manager's effort for the inspection system200can be reduced, and since the position of the camera module is measured at the fixed position, the alignment state of the camera module can be accurately determined. Also, the object in the image taken by the alignment camera210may be always shown in the same size.

The inspection system200may include an inspection board driving unit260. The inspection board driving unit260may be coupled to the upper side of the base unit250, be located in a first direction of the alignment stage220, and be configured for moving the inspection board240in a first direction or in a direction opposite to the first direction. The test board driving unit26may be coupled to the upper surface of the test board accommodating unit311.

The inspection board driving unit260may include a driving unit base, a first direction guide shaft261, a guide block262, and an inspection board coupling unit263. The inspection board driving unit260may include a driving unit base to be coupled with the base unit250. A first direction guide shaft261may be formed on the upper side of the driving unit base. The first direction guide shaft261may extend in the first direction. The inspection board driving unit260may include a guide block262moving along the first direction guide shaft261. For example, the guide block262may have a nut engaged with the first direction guide shaft261, and the guide block262may move in the first direction or in a direction opposite to the first direction according to the direction of rotation of the first direction guide shaft261. The guide block262may be coupled to the inspection board coupling unit263. The inspection board coupling unit263may be configured to couple the inspection board240and the guide block262. The inspection board240may move in a first direction or in a direction opposite to the first direction together with the inspection board coupling unit263.

A lower side of the second direction movement stage may include a slider. The slider of the second direction movement stage is coupled to the second direction guide rail of the base stage to slide in the second direction or in a direction opposite to the second direction.

The inspection system200may include an inspection board240. The inspection board240may be coupled to an upper side of the inspection board driving unit260. In addition, the inspection board240may be configured to inspect the camera module on the support socket230. The inspection board240may be coupled with the camera module to perform inspection.

The inspection board240may include an inspection sub-board241. The inspection sub-board241may move up and down with respect to the inspection board240. After the inspection board240moves in the opposite direction to the first direction and is located above the camera module, the inspection sub-board241descends so that the connector of the camera module and the connector of the inspection sub-board241can be connected. Accordingly, the inspection board240may perform an inspection of the camera module. However, it is not limited thereto, and the inspection board240may be coupled with the camera module while moving up and down.

Hereinafter, the operation of the inspection system200by the control unit100will be described in detail.

FIG.5explains why the inspection system according to an embodiment of the present disclosure needs to check the alignment state of the camera module.

Referring toFIG.5(a), an accommodation groove501for accommodating the camera module500may be formed on the upper surface of the support socket230. The camera module500may be accommodated in the accommodation groove501of the support socket230for inspection. The accommodation groove501formed in the support socket230may be slightly larger than the camera module500in order to easily accommodate the camera module500. Accordingly, the camera module500may be moved minutely within the support socket230. Also, there may be cases where a connector coupled to the camera module is coupled to the camera module at an angle due to an error in the assembly process.

Referring toFIG.5(b), the camera module510may be perfectly aligned. For example, an extension cable512from the camera module510to the connector513may be parallel to the alignment line511.

The camera module520and the camera module530may be in a non-aligned state. Extension directions521and531of the extension cables522and532from the camera modules520and530to the connectors523and533may form a predetermined angle with the alignment line511. When trying to combine the connectors523and533of the camera modules520and530with the connector formed on the inspection board240, the connector of the inspection board240or the connector523533of the camera modules520and530may be damaged. Therefore, alignment of the camera module may need to be necessarily performed prior to inspection. Therefore, the following process is performed.

FIG.6is a flowchart illustrating an operation of an inspection system according to an embodiment of the present disclosure.FIG.7is a drawing for explaining the operation of an inspection system according to an embodiment of the present disclosure.FIG.8is a drawing for explaining the operation of an inspection system according to an embodiment of the present disclosure.FIG.9is a drawing for explaining an operation of an inspection system according to an embodiment of the present disclosure.

Referring toFIGS.6and7, the inspection system200may inspect the camera module710. The inspection system200may perform the following process to inspect the camera module. More specifically, the control unit100may control components included in the inspection system200to perform the following operations.

The alignment camera210may perform step610of obtaining an image810of the camera module by photographing a predetermined area of the camera module710on the support socket230. The predetermined area may be an area of a connector coupled to the camera module710. For example,FIG.8may show an image810of a camera module capturing a predetermined area.

The control unit100may compare the image810of the camera module with the first pattern image850to perform step620of obtaining the position821of the first point included in the image of the camera module. The first pattern image may be a pre-stored template image. The first pattern image may be an image stored in the control unit100before obtaining the image810of the camera module. The first pattern image may be an image of one side of the connector of the camera module.

The first pattern image850may include a positioning point851at a predetermined location. InFIG.8, the positioning point851is displayed on the first pattern image850for convenience of explanation, but the positioning point851may not be displayed on the first pattern image. The control unit100may determine a specific position of the first pattern image850as a positioning point851. The position of the positioning point851may be previously determined. The control unit100may store the coordinates of the positioning point851for the first pattern image. The positioning point851may be at least one of the center, upper left, upper right, lower left, or lower right points of the first pattern image850, but it is not limited to this.

A step620of obtaining the location of the first point620may further include the following process. The control unit100may perform a step of determining a first region820most similar to the first pattern image850in the image810of the camera module. The size of the first region820may be the same as that of the first pattern image850. To determine the first region820, the control unit100may use a predetermined pattern matching algorithm. The control unit100may perform a step of obtaining a position within the first region820corresponding to the position of the positioning point851of the first pattern image850as the position821of the first point.

A step of obtaining the location within the first region as the location821of the first point may include the following process. When the similarity between the first region820and the first pattern image850is less than a predetermined threshold similarity, the control unit100may perform a step of outputting a signal indicating that there is an error in the camera module710. Both ends of the connector coupled to the camera module710may perform inspection or be crushed during assembly process. The control unit100may obtain a similarity between the first pattern image850and the first region820of the image810of the camera module. The control unit100determines the first region820most similar to the first pattern image850in the image810of the camera module, but when the obtained similarity is less than a predetermined threshold similarity, the image810of the camera module or the connector of the camera module710may be determined to have a problem. For example, the control unit100may determine that the connector of the camera module710is crushed. The control unit100may perform a step of outputting a signal indicating that the camera module710has a problem. Also, the control unit100may not perform steps620to680. A user may take necessary actions based on the signal output from the inspection system200.

When the similarity between the first region820and the first pattern image850is greater than or equal to the threshold similarity, the control unit100may perform a step of obtaining a position within the first region820corresponding to the position of the positioning point of the first pattern image850as the position821of the first point. That is, when the similarity between the first region and the first pattern image is greater than or equal to the threshold similarity, the control unit100may perform steps620to680.

The control unit100compares the image810of the camera module with the second pattern image860, and perform a step630of obtaining the position831of the second point included in the image810of the camera module. The second pattern image860may be a pre-stored template image. The second pattern image860may be an image stored in the control unit100before obtaining the image810of the camera module. The second pattern image860may be an image of the other side of the connector of the camera module. The other side of the connector shown in the second pattern image860may be the opposite side of the one side of the connector shown in the first pattern image860.

The second pattern image860may include a positioning point861at a predetermined location. InFIG.8, the positioning point861is displayed on the second pattern image860for convenience of description, but the positioning point861may not be displayed on the second pattern image860. The control unit100can determine a specific position of the second pattern image860as a positioning point861. The position of the positioning point861may be previously determined. The control unit100may store the coordinates of the positioning point861for the second pattern image860. The positioning point861may be at least one of the center, upper left, upper right, lower left, or lower right points of the second pattern image860, but it is not limited to this.

The second pattern image860may be a mirror image or an image rotated by 180 degrees of the first pattern image850. The size of the second pattern image860may be the same as that of the first pattern image850. The second pattern image860may be a mirror image of the first pattern image850on a horizontal axis. The control unit100may determine a mirror image or 180 degree rotation image of the first pattern image850as the second pattern image860. That is, the control unit100may determine the first pattern image850and the second pattern image860using one pattern image.

A step630of obtaining the location of the second point may further include the following process. The control unit100may perform a step of determining a second region830most similar to the second pattern image860in the image810of the camera module. The size of the second region830may be the same as that of the second pattern image860. To determine the second region830, the control unit100may use a predetermined pattern matching algorithm. The control unit100may perform a step of obtaining a position within the second region830corresponding to the position of the positioning point861of the second pattern image860as the position831of the second point.

Obtaining the second region viewing position as the second point position may include the following process. When the similarity between the second region830and the second pattern image860is less than a threshold similarity, the control unit100may perform a step of outputting a signal indicating that there is an error in the camera module710. Both ends of the connector coupled to the camera module710may perform inspection or be crushed during assembly process. The control unit100may obtain a similarity between the second pattern image860and the second region830of the image810of the camera module. The control unit100determines the second region830most similar to the second pattern image860in the image810of the camera module, but when the obtained similarity is less than a predetermined threshold similarity, the image810of the camera module or the connector of the camera module710may be determined to have a problem. For example, the control unit100may determine that the connector of the camera module710is crushed. The control unit100may perform a step of outputting a signal indicating that the camera module710has a problem. Also, the control unit100may not perform steps620to680. A user may take necessary actions based on the signal output from the inspection system200.

When the similarity between the second region830and the second pattern image860is greater than or equal to the threshold similarity, a step of obtaining a position in the second region corresponding to the position of the positioning point of the second pattern image860as the position831of the second point may be performed. That is, when the similarity between the second region830and the second pattern image860is greater than or equal to the threshold similarity, the control unit100may perform steps620to680.

After obtaining the position of the second point630, the control unit100may perform the following process. After step630, the control unit100may perform a step of determining a difference distance between the position of the first point and the position of the second point. The control unit100may obtain a difference distance by subtracting the coordinate value of the position831of the second point from the coordinate value of the position821of the first point. Alternatively, the control unit100may obtain the difference distance by subtracting the coordinate value of the position821of the first point from the coordinate value of the position831of the second point. A unit of the difference distance may be the number of pixels.

The control unit100may perform a step of determining an absolute value of a difference between the difference distance and the predetermined basic distance. The basic distance is a predetermined value, which may be stored by the control unit100. A unit of the basic distance may be the number of pixels. The basic distance may be a length that a connector coupled to the camera module710must satisfy. The basic distance may be input in advance by a system designer and may be changed by a user's input.

The control unit100may obtain an absolute value after subtracting the difference distance and the basic distance. The control unit100may perform a step of outputting a signal indicating that there is an error in the camera module when the absolute value is greater than or equal to a predetermined tolerance. That is, when the difference between the difference distance and the basic distance is too large, the control unit100may determine that there is a problem with the connector of the camera module710or a problem with the image of the camera module710. The control unit100may output a signal indicating that there is a problem with the connector of the camera module710or that there is a problem with the image of the camera module710. Also, the control unit100may not perform steps620to680. A user may take necessary actions based on the signal output from the inspection system200.

When the absolute value is less than a predetermined tolerance, the control unit100may perform a step of obtaining the center position or alignment line. That is, the control unit100may perform steps620to680.

The control unit100may perform step640of obtaining the central position840of the position821of the first point and the position831of the second point. In addition, the control unit100may perform step650of obtaining an alignment line connecting the position821of the first point and the position831of the second point.

The control unit100may perform step660of obtaining a difference vector between the center position840and a predetermined reference position. The control unit100may obtain a difference vector by subtracting the coordinate value of the reference position from the coordinate value of the center position840. However, the present invention is not limited thereto, and the control unit100may obtain a difference vector by subtracting the coordinate value of the center position840from the coordinate value of the reference position. As for the coordinate values, the x-axis value may increase toward the right, and the y-axis value may increase toward the bottom, starting with the upper-left pixel of the image810of the camera module as the origin. A difference vector can have a magnitude and a direction. A process of obtaining the reference position will be described later.

The control unit100may perform step670of obtaining a rotation angle between an alignment line and a predetermined reference line. The rotation angle may be a value having a rotation magnitude and a rotation direction. The control unit100may determine whether the alignment line is displaced clockwise or counterclockwise from the reference line in order to determine the rotation direction. Also, the control unit100may determine an angle formed between the reference line and the alignment line as the size of rotation. A method of obtaining the reference line will be described later.

The control unit100may perform step680of driving the alignment stage based on at least one of a difference vector and a rotation angle so that the center position840is located at the reference position and the alignment line coincides with the predetermined reference line. More specifically, the control unit100may drive the first stage410or the second stage420based on the difference vector. The value of the x-axis of the difference vector may be related to the first-stage stage410, and the value of the y-axis of the difference vector may be related to the second-stage stage420. However, it is not limited thereto, and the value of the x-axis of the difference vector may be related to the second-stage stage420and the value of the y-axis of the difference vector may be related to the first-stage stage410. Also, the control unit100may drive the third stage430based on the rotation angle.FIG.9illustrates a state in which the control unit100drives the first stage410or the second stage420based on the difference vector according to an embodiment of the present disclosure.

The control unit100may previously store information on how much the first-stage stage410or the second stage420should be moved in which direction according to the direction (+/−) or magnitude of the difference vector in the x-axis direction. In addition, the control unit100may previously store information on how much the second stage420or the first stage410should be moved in which direction according to the direction (+/−) and magnitude of the difference vector in the y-axis direction. The control unit100may determine the size and direction of the motion of the first stage410and the second stage420by applying the difference vector to previously stored information. Also, the control unit100may control the first stage410and the second stage420to be moved based on the determined size and direction of the movement.

The control unit100may previously store information on how much the third stage430should be moved according to the size of the rotation angle. Also, the control unit100may previously store information on in which direction the third stage430should be moved according to the direction of the rotation angle. The control unit100may determine the size and direction of the movement of the third stage430by applying the rotation angle to previously stored information. In addition, the control unit100may control the third stage430to move based on the determined magnitude and direction of the movement.

The control unit100may repeat steps610to680so that the center position840is located at the reference position and the alignment line coincides with the predetermined reference line.

Hereinafter, a method for automatically determining a reference position and reference line will be described.

FIG.10is a flowchart illustrating an operation of an inspection system according to an embodiment of the present disclosure. Also,FIG.11is a drawing for explaining the operation of the inspection system according to an embodiment of the present disclosure.

First, referring toFIG.11, a first inspection board alignment point1111and a second inspection board alignment point1112may be displayed on the upper side of the inspection board240. The first inspection board alignment point1111and the second inspection board alignment point1112may be formed along the second direction.

Based on the first inspection board alignment point1111and the second inspection board alignment point1112formed on the upper side of the inspection board240, the control unit100may create a reference position and a reference line. The steps ofFIG.10may be performed before the steps ofFIG.6are performed. Also, the steps ofFIG.10may not be performed every time the camera module is inspected. When the steps ofFIG.10are performed, since the reference position and reference line are determined, there may be no problem in inspecting a plurality of camera modules thereafter. However, the steps ofFIG.10may be performed at a predetermined cycle, initial setting is required or may be performed before inspecting the camera module according to the user's needs.

The inspection system200may perform the following process. The control unit100may perform step1010of moving the inspection board240in a direction opposite to the first direction by using the inspection board driving unit.FIG.11(a)may indicate a state in which step1010has been completed. Referring toFIG.11(a), the inspection board may be positioned above the support socket230by step1010. In step1010, the inspection board240may be positioned between the alignment camera210and the support socket230. Accordingly, the alignment camera210may photograph the inspection board240. Moving the inspection board240in a direction opposite to the first direction may be moving the inspection board240to an inspection position. However, the camera module may not be mounted on the support socket230, and in the step ofFIG.10, the inspection board240does not inspect the camera module, but may be used to create a reference position and reference line.

The control unit100may perform step1020of obtaining an image of the inspection board240using the alignment camera210. The position of the alignment camera210may be the same in step610and step1020. However, since the support socket230is covered by the inspection board240, the alignment camera210may obtain an image1110of the inspection board240. An image1110of the inspection board240may be the same asFIG.11(b).

The control unit100may perform step1030of determining the position of the first inspection board alignment point and the second inspection board alignment point in the image of the inspection board240. As already described, the first inspection board alignment point1111and the second inspection board alignment point1112may be displayed on the upper surface of the inspection board240. In addition, the first inspection board alignment point1111and the second inspection board alignment point1112may correspond to the position of the connector1120formed on the lower side of the inspection board240. That is, one side of the connector1120is located at a position corresponding to the first inspection board alignment point1111on the lower surface of the inspection board240, and the other side of the connector1120is located at a position corresponding to the second inspection board alignment point1112on the lower surface of the inspection board240. The control unit100obtains the position of the first inspection board alignment point1111and the second inspection board alignment point1112in the image of the inspection board240, thereby recognizing the position of the connector on the lower side of the inspection board240.

The control unit100may perform step1040of determining the center of the first inspection board alignment point1111and the second inspection board alignment point1112as a reference position. The reference position may be the center of a connector located on the inspection board. Also, the center position840described above may be the center of a connector coupled to the camera module710. By matching the reference position and the center position840in a later step680, the positions of the connector of the inspection board and the connector of the camera module710can be aligned.

In addition, the control unit100may perform step1050of determining a line connecting the position of the first inspection board alignment point1111and the position of the second inspection board alignment point1112as a reference line. The reference line may indicate a longitudinal direction of the connector located on the inspection board. In addition, the alignment line described above may indicate a longitudinal direction of a connector coupled to the camera module710. By matching the reference line and the alignment line in a later step680, the positions of the connector of the inspection board240and the connector of the camera module710can be aligned.

The control unit100may perform step1060of moving the inspection board in the first direction by using the inspection board driving unit. In step1060, the camera module710may be placed on the support socket230. Since the reference position and reference line are obtained by performing steps1010to1050, the control unit100may perform a step for aligning the camera modules as shown inFIG.6. For example, the inspection system200may place the camera module710on the support socket230. That is, inspection system200may be in a state as shown inFIG.7. In addition, the alignment camera210may perform step610of obtaining an image of the camera module710by photographing a predetermined region of the camera module710on the support socket.

FIG.12is a flowchart illustrating an operation of an inspection system according to an embodiment of the present disclosure. In addition,FIG.13is a drawing for explaining an operation of an inspection system according to an embodiment of the present disclosure.

The steps ofFIG.12may be performed after the camera modules are aligned by the steps included inFIG.6.

After driving the alignment stage, the control unit100may perform step1210of moving the inspection board in a direction opposite to the first direction by using the inspection board driver. Moving the inspection board240in a direction opposite to the first direction may mean that the inspection board240is positioned above the camera module710. In addition, the connector of the inspection board240may be in a state capable of being coupled with the connector of the camera module710. Because the steps ofFIG.12are operations performed after the steps ofFIG.10and the steps ofFIG.6, the connector of the inspection board240is aligned with the connector of the camera module710by the steps ofFIG.6.

The control unit100may perform step1220of coupling the inspection board and the camera module on the support socket by moving the inspection board240downward. The inspection board240is lowered so that the connector of the inspection board240and the connector of the camera module710can come into contact. However, it is not limited thereto, and the inspection sub-board241included in the inspection board240descends so that the connector of the inspection board240and the connector of the camera module710may come into contact. By step1210, the inspection system200may be in a state as shown inFIG.13. UnlikeFIGS.7and9, it can be seen inFIG.13that the inspection board240is close to the support socket230.

The control unit100may perform step1230of obtaining a test result by testing the camera module using the inspection board. After the connector of the inspection board240and the connector of the camera module710come into contact, the inspection board240may perform inspection while exchanging signals with the camera module710. In addition, the inspection board240may obtain a test result based on the movement of the camera module and the signal received from the camera module.

The control unit100may perform step1240of separating the camera module and the inspection board by moving the inspection board upward. That is, after obtaining the test result, the connector of the inspection board240and the connector of the camera module710may be separated. In addition, the control unit100may perform step1250of moving the inspection board in the first direction by using the inspection board driving unit. As such, the inspection system200can quickly align the camera module using the hardware structure ofFIG.2and the steps ofFIG.6and accurately obtain test results by performing the steps ofFIG.12.

So far, we have looked at various embodiments. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent scope will be construed as being included in the present invention.

On the other hand, the above-described embodiments of the present invention can be written as a program that can be executed on a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium. The computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM, floppy disk, hard disk, etc.) and optical reading media (e.g., CD-ROM, DVD, etc.).