KR100884051B1 - Apparatus and method for inspecting soldering by modifying grab sequency - Google Patents

Abstract

A soldering inspection apparatus and method in which a grapple sequence is changed are disclosed. A solder inspecting apparatus according to an embodiment of the present invention is an apparatus for continuously detecting an image of solder by imaging at least one frame unit, and includes a camera, a grabber, at least two lights, a lighting controller, . Wherein each of the one or more frames includes an image photographed with at least two lights. The grabber digitizes an electrical image signal photographed by the camera. At least two illuminations each provide an optical environment in which the camera can capture images for each of the at least two illumination directions. The lighting control unit controls the at least two lights. The processor detects whether or not a soldering error has occurred based on the digitized video signal, and controls the grabber and the lighting controller. In this case, it is preferable that the illumination control unit controls the at least two or more lights so that the illumination direction taken by the camera first in the next frame is the same as the illumination direction taken last in the previous frame. In the solder inspecting apparatus according to the embodiment of the present invention, when the frame is moved, since the last light turned on in the previous frame is used as the first light even after the next light is moved to the next frame, the image is grabbed, There is an advantage that it can be reduced.

Grapple sequence, solder inspection device, grabber,

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a soldering apparatus and a soldering apparatus,

BRIEF DESCRIPTION OF THE DRAWINGS A brief description of each drawing is provided to more fully understand the drawings recited in the description of the invention.

FIG. 1 is a timing chart showing an inspection procedure when using a general illumination method based on three frames.

2 is a block diagram of a solder testing apparatus according to an embodiment of the present invention.

3 is a view showing a sequence in which an image is grabbed by a camera in a solder inspecting apparatus according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering inspection apparatus, and more particularly, to a soldering inspection apparatus and method capable of shortening an inspection time by changing an order in which an image to be picked up at the time of soldering inspection is changed.

When an electronic device is manufactured using an SMT (Surface Mount Technology) process in which a component is placed on an electronic substrate, the component is bonded to the substrate by soldering. In other words, it is very important to check whether the soldering is properly performed in the mass production stage since soldering must be performed properly for the electronic products to operate properly.

Generally, whether soldering is properly performed in the SMT process is inspected using a three-dimensional inspection method, and one or more cameras and one or more laser projectors are used for this purpose. In addition, the lead excitation is mainly inspected using a spot laser (using one camera and one laser projector).

As described above, when inspecting whether soldering is properly performed or inspecting the lead lifting, it is necessary to take a process of photographing a soldering part by using a camera. In this case, machine vision is often used.

Machine vision means to acquire information about a photographed object using a processor based on the photographed image, and is a type of visual recognition system for inspecting a product instead of a person using a camera .

In machine vision, an optical characteristic of an object is generally converted into an electric signal by using a CCD camera, and then converted into a digital signal. Then, the converted digital signal is subjected to a series of processes such as deformation, measurement, To obtain desired information. Current machine vision is used mainly in the fields of product defect recognition, measurement of specific parts, monitoring of process processes, and so on.

In general, machine vision includes a camera, a lighting device, a frame grabber, and a processor. As is generally known, a camera converts optical information of an object into an electrical signal and outputs it, and the lighting device optically characterizes the camera so as to input desired information of the object. The frame grabber receives the electrical signal converted by the camera and digitizes it. On the other hand, the processor applies a series of processes (processing, transformation, simplification, etc.) to digitized image information to produce desired results.

On the other hand, in the machine vision, in order for the camera to obtain optical information of a desired object, the illumination device must adjust the optical characteristics of the object. In order for the illumination device to operate, a processor (computer) controls the illumination controller, Should be turned on.

In the field of soldering inspection equipment, it is important to have the ability to detect whether the solder is solid or not and the tack time required for the inspection. That is, the detection capability of the soldering apparatus should be high and the inspection time should be short.

Factors that can reduce inspection time of soldering inspection equipment include robot movement time, inspection progress time, camera grip time, and conveyor loading and unloading time.

As for the camera grab time, the machine vision generally illuminates alternately in the vertical direction (V) and the horizontal direction (H), so that for each frame, the images are displayed in the V-H-V-H- ... ... Grab in order. Here, the frame is the size of the image that the camera can see at a time.

FIG. 1 is a timing diagram showing an inspection sequence when using a general illumination method based on three frames. FIG.

Basically, the image should be grabbed in two lights V and H per frame. For convenience of explanation, the following description will be made taking into consideration only the grab operation time, the illumination on / off time, and the LED delay time while ignoring the exposure time and the like necessary for grabbing the image.

First, when the robot moves to the first frame (Frame 0), the V-light is turned on and after the LED delay time (for example, 10 ms), the camera grabs the image in the V illumination (V illumination Grab). When the image grab in the V illumination is finished, the image grab in the H illumination is performed (H illumination grab). The image grab operation in the H illumination is performed similar to the grab operation in the V illumination.

When the image grab operation in V and H illumination in the first frame (Frame 0) is finished, the robot moves to the second frame (Frame 1). The image grab operation after the robot moves to the second frame (Frame 1) is performed similar to the image grab operation in the first frame. That is, after the V light is first turned on and the LED delay time has elapsed, the camera grabs the image in the V light (V light grab). When the image grab operation in the V illumination is completed, the image grab operation in the H illumination is performed (H surface grab). For the second and subsequent frames, the image grab operation is performed for the necessary number of frames in the same manner as the above-described manner.

In this manner, when the image grab operation is performed by the number of frames required for the inspection, the image grab operation in the V illumination and the image grab operation in the H illumination are alternately performed, so that the LED delay time is required every time the operation is performed. Therefore, there is a problem that the inspection time is prolonged due to repeated LED delay time. Therefore, there is a need for a method that can reduce the inspection time by decreasing the LED delay time by appropriately adjusting the order of the V illumination and the H illumination.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a solder inspecting apparatus capable of reducing inspection time by adjusting the order of vertical illumination and horizontal illumination.

It is another object of the present invention to provide a soldering inspection method capable of reducing inspection time by adjusting the order of vertical illumination and horizontal illumination.

According to an aspect of the present invention, there is provided a solder inspecting apparatus for detecting an error in soldering by continuously photographing an image in units of one or more frames, the apparatus comprising a camera, a grabber, , A lighting control section, and a processor. Wherein each of the one or more frames includes an image photographed in at least two illumination directions. The grabber digitizes an electrical image signal photographed by the camera. At least two illuminations each provide an optical environment in which the camera can capture images for each of the at least two directions. The lighting control unit controls the at least two lights. The processor detects whether or not a soldering error has occurred based on the digitized video signal, and controls the grabber and the lighting controller. In this case, it is preferable that the illumination control unit controls the at least two or more lights so that the illumination direction of the camera taken first in the next frame is the same as the illumination direction of the last taken in the previous frame.

On the other hand, the illumination control unit turns on illumination for the illumination direction taken by the camera, turns off the illumination for the taken illumination direction after a predetermined time elapses, and turns on the illumination for the taken illumination direction .

Preferably, the illumination is a light emitting diode (LED) illumination and the predetermined time is a delay time of the LED.

Preferably, the at least two illumination directions are a vertical direction and a horizontal direction.

According to another aspect of the present invention, there is provided a method for detecting a soldering error by continuously photographing an image in units of one or more frames, wherein each of the one or more frames includes at least two illumination directions Wherein the step of grabbing an image for each of the at least two frames comprises grabbing an image for each of the one or more frames, And in the subsequent frame, it is preferable that the illumination direction for grabbing the last image in the previous frame and the illumination direction for grabbing the first image in the next frame are equal to each other.

Wherein the step of grabbing an image for each of the directions comprises grabbing an image continuously for each illumination direction, and wherein grabbing an image for a given illumination direction comprises: And taking an image of the predetermined illumination direction after a predetermined time has elapsed.

In this case, the light is an LED (light emitting diode) illumination, and the predetermined time is preferably a delay time of the LED.

While the at least two directions are preferably vertical and horizontal.

If the direction in which the image is finally grabbed is the vertical direction, the direction in which the first image is grabbed is the vertical direction, and if the direction in which the image is finally grabbed is the horizontal direction, It is preferable that the direction of grabbing is also the horizontal direction.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

2 is a block diagram of a solder testing apparatus according to an embodiment of the present invention. The solder inspection apparatus 200 continuously photographs an image in units of one or more frames and checks whether soldering is properly performed on the substrate, i.e., a soldering error.

The soldering inspection apparatus 200 includes a camera 210, a grabber 230, at least two lights 250-1 to 250-n, a lighting controller 270, and a processor 290. Similar to that described in Fig. 1, each of the one or more frames includes an image photographed in at least two directions (e.g., vertical and horizontal directions). Although the following description focuses on the operation of grabbing an image captured by the camera in the vertical direction and the horizontal direction, those skilled in the art will appreciate that the present invention is not limited thereto You will know.

The grabber 230 digitizes an electrical image signal photographed by the camera 210. [ At least two lights 250-1 to 250-n (e.g., vertical illumination (hereinafter referred to as 250-1) and horizontal illumination (hereinafter referred to as 250-2) Vertical direction and horizontal direction), respectively, of the camera. For example, the vertical illumination is turned on when the camera takes images in the vertical direction, and the horizontal lights are turned on when the images are taken in the horizontal direction.

The illumination control unit 270 controls at least two lights 250-1 to 250-n. The operation of the illumination control unit 270 to control the lights 250-1 to 250-n will be described later with reference to Fig. The processor 290 detects whether or not a soldering error has occurred based on the digitized video signal. The processor 290 also controls the grabber 230 and the illumination controller 270.

In general, the time taken for the brightness of the illumination to reach the brightness that the camera can capture after turning on the illumination is called the setting time or the delay time.

As shown in Fig. 1, in the case where the directions in which the images are taken in the respective frames are the same (in other words, when the vertical direction is firstly photographed in each frame and the horizontal direction is photographed later) When you cross over, shooting takes place in different directions. That is, at the end of each frame, the image is taken in the horizontal direction, and the first image is taken in the vertical direction. The lighting must be newly turned on for all the cases where the photographing is performed, so an illumination delay time is required for each photographing.

The present invention proposes a method of reducing solder inspection time by reducing the illumination delay time by adjusting the grab sequence in order to capture an image. Hereinafter, the operation of the solder testing apparatus according to the embodiment of the present invention will be described with reference to FIG. In the meantime, a person skilled in the art will understand solder inspecting apparatuses other than the operation of grabbing an image. Therefore, in the following description, the operation of grabbing an image will be mainly described.

3 is a view showing a sequence in which an image is grabbed by a camera in a solder inspecting apparatus according to an embodiment of the present invention. As shown in FIG. 3, the solder inspecting apparatus according to the embodiment of the present invention has different directions for grabbing images in neighboring frames.

That is, in the first frame (Frame 0), the image is first grabbed in the vertical direction (V), and finally the image is grabbed in the horizontal direction (H). In the second frame (Frame 1), the image is first grabbed in the horizontal direction (H), and finally the image is wrapped in the vertical direction (V). By doing so, the lighting from the previous frame can be used as it is when the previous frame is moved to the next frame, thus reducing the illumination delay time per frame.

This principle of the present invention can be implemented by allowing the lighting controller 270 to control the lights 250-1 to 250-n. That is, the illumination control unit 270 determines whether the illumination direction in which the camera 210 first picks up a predetermined frame (for example, Frame 1 or Frame 2) in the previous frame (for example, Frame 0 or Frame 1) And controls at least two lights 250-1 to 250-n so as to be in the same direction as the lighting direction of the last photographing.

The operation of the illumination control unit 270 to control the illumination is as follows. When the camera captures an image in the vertical direction, the illumination control unit turns on illumination (i.e., vertical illumination) for the direction in which the image is captured. On the other hand, the illumination control unit 270 turns off illumination (i.e., vertical illumination) for the imaging direction after a predetermined time has elapsed, and turns on illumination (e.g., horizontal illumination) for the next imaging direction. At this time, it is preferable that the predetermined time is the time from when the illumination is brighter to an appropriate brightness for the photographing of the camera, and then the photographing of the camera is completed. Also, when the illumination is an LED (light emitting diode) illumination, the predetermined time is preferably the delay time of the LED.

For example, when the image is grabbed in the horizontal direction at the end of the previous frame (Frame 0) (in this case, the illumination in the horizontal direction will be turned on) And controls the lights 250-1 to 250-n so that the image is grabbed in the horizontal direction. Therefore, in this case, the illumination control unit 270 controls the illumination so that the illumination 250-1 in the horizontal direction is maintained as it is.

Similarly, when the image is grabbed in the vertical direction at the end of the previous frame (Frame 1) (in this case, vertical illumination will be turned on) And controls the lights 250-1 to 250-n so that an image is grabbed in the direction of the image. Therefore, in this case, the illumination control unit 270 controls the illumination so that the illumination 250-2 in the vertical direction is maintained.

Hereinafter, a soldering inspection method according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG. Those skilled in the art will be able to understand solder inspecting apparatuses other than the operation of grabbing an image. Therefore, in the following description, an operation of grabbing an image will be mainly described.

The solder inspecting method continuously captures an image in units of one or more frames to detect a soldering error. Wherein each of the one or more frames comprises an image photographed in at least two directions.

The soldering inspection method includes grabbing an image for each of the one or more frames. The step of grabbing the image for each of the frames also includes grabbing the image for each of at least two directions. At this time, in a continuous frame (for example, Frame 0 and Frame 1, or Frame 1 and Frame 2), the direction in which the image is grabbed last in the previous frame (for example, Frame 0 or Frame 1) Direction) and the direction (horizontal direction or vertical direction) in which the first image is grabbed in the next frame (Frame 1 or Frame 2) are preferably equal to each other.

The step of grabbing the image for each of at least two directions includes grabbing the image continuously for each direction. That is, in any one frame, the camera grabs images continuously in at least two directions.

For example, in the first frame (Frame 0), the image is grabbed in the vertical direction, and then the image is grabbed in the horizontal direction in succession. Similarly, in the second frame (Frame 1), the image is grabbed in the horizontal direction, and then the image is grabbed in the vertical direction in succession. It should be noted that the order of grabbing in each frame is not always the same.

The step of grabbing an image in a predetermined direction includes the steps of turning on illumination for a predetermined direction and photographing the image in the predetermined direction after a predetermined time has elapsed.

For example, when an image is grabbed in the vertical direction, illumination for the direction in which it is grabbed (i.e., vertical illumination) is turned on. The illumination (i.e., the vertical illumination) for the direction in which the image is taken after the predetermined time has elapsed is turned off, and the illumination (for example, the horizontal illumination) for the direction to be photographed next is turned on.

At this time, it is preferable that the predetermined time is the time from when the illumination is brighter to an appropriate brightness for the photographing of the camera, and then the photographing of the camera is completed. Also, when the illumination is an LED (light emitting diode) illumination, the predetermined time is preferably the delay time of the LED.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

As described above, in the solder inspecting apparatus according to the embodiment of the present invention, when the frame is moved, since the light that has been turned on in the previous frame is moved to the next frame, the image is grabbed to reduce the one- There is an advantage. Accordingly, the inspection time can be shortened by about 10 msec per frame as compared with the conventional soldering inspection apparatus.

Claims (9)

A method of detecting a soldering error by continuously imaging an image in units of one or more frames, wherein each of the one or more frames includes an image taken in a vertical direction and a horizontal direction, Wherein said solder testing method comprises grabbing an image for each of said one or more frames, Wherein grabbing an image for each of the frames comprises grabbing an image for each of the vertical and horizontal directions, Wherein the illumination direction for grabbing the last image in the previous frame and the illumination direction for grabbing the first image in the next frame are the same in successive frames. The method of claim 1, wherein grabbing an image for each of the vertical and horizontal directions comprises: And continuously grabbing the image for each direction, Wherein the step of grabbing an image for a selected one of the directions comprises: Turning on illumination for the selected one direction; And And taking an image of the selected one direction after a lapse of time. 3. The method of claim 2, The light is an LED (light emitting diode) Wherein the time is a delay time of the LED. delete The method according to claim 1, If the direction in which the image is grabbed last is the vertical direction, the direction in which the first image is grabbed is also the vertical direction, Wherein when the direction of grabbing the image is the horizontal direction, the direction of grabbing the first image is also the horizontal direction. An apparatus for continuously detecting images of soldering errors in at least one frame unit, wherein each of the one or more frames includes an image photographed in a vertical direction and a horizontal direction, camera; A grabber for digitizing an electric image signal photographed by the camera; Two lights each providing an optical environment in which the camera can capture an image for each of the vertical and horizontal directions; A lighting controller for controlling the two lights; And And a processor for detecting whether or not a soldering error has occurred based on the digitized video signal and controlling the grabber and the lighting controller, Wherein the lighting control unit controls the two lights so that the direction in which the camera first photographs in the next frame is the same as the direction in which the camera takes the last photograph in the previous frame. 7. The lighting control apparatus according to claim 6, Wherein the controller turns on illumination for a direction in which the camera is to be photographed, turns off illumination for the photographing direction after a lapse of time, and turns on illumination for a next photographing direction. 8. The method of claim 7, The light is an LED (light emitting diode) Wherein the time is a delay time of the LED. delete

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